| 1 | /* GNU/Linux native-dependent code common to multiple platforms. |
| 2 | |
| 3 | Copyright (C) 2001-2019 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | #include "inferior.h" |
| 22 | #include "infrun.h" |
| 23 | #include "target.h" |
| 24 | #include "nat/linux-nat.h" |
| 25 | #include "nat/linux-waitpid.h" |
| 26 | #include "common/gdb_wait.h" |
| 27 | #include <unistd.h> |
| 28 | #include <sys/syscall.h> |
| 29 | #include "nat/gdb_ptrace.h" |
| 30 | #include "linux-nat.h" |
| 31 | #include "nat/linux-ptrace.h" |
| 32 | #include "nat/linux-procfs.h" |
| 33 | #include "nat/linux-personality.h" |
| 34 | #include "linux-fork.h" |
| 35 | #include "gdbthread.h" |
| 36 | #include "gdbcmd.h" |
| 37 | #include "regcache.h" |
| 38 | #include "regset.h" |
| 39 | #include "inf-child.h" |
| 40 | #include "inf-ptrace.h" |
| 41 | #include "auxv.h" |
| 42 | #include <sys/procfs.h> /* for elf_gregset etc. */ |
| 43 | #include "elf-bfd.h" /* for elfcore_write_* */ |
| 44 | #include "gregset.h" /* for gregset */ |
| 45 | #include "gdbcore.h" /* for get_exec_file */ |
| 46 | #include <ctype.h> /* for isdigit */ |
| 47 | #include <sys/stat.h> /* for struct stat */ |
| 48 | #include <fcntl.h> /* for O_RDONLY */ |
| 49 | #include "inf-loop.h" |
| 50 | #include "event-loop.h" |
| 51 | #include "event-top.h" |
| 52 | #include <pwd.h> |
| 53 | #include <sys/types.h> |
| 54 | #include <dirent.h> |
| 55 | #include "xml-support.h" |
| 56 | #include <sys/vfs.h> |
| 57 | #include "solib.h" |
| 58 | #include "nat/linux-osdata.h" |
| 59 | #include "linux-tdep.h" |
| 60 | #include "symfile.h" |
| 61 | #include "common/agent.h" |
| 62 | #include "tracepoint.h" |
| 63 | #include "common/buffer.h" |
| 64 | #include "target-descriptions.h" |
| 65 | #include "common/filestuff.h" |
| 66 | #include "objfiles.h" |
| 67 | #include "nat/linux-namespaces.h" |
| 68 | #include "common/fileio.h" |
| 69 | #include "common/scope-exit.h" |
| 70 | |
| 71 | #ifndef SPUFS_MAGIC |
| 72 | #define SPUFS_MAGIC 0x23c9b64e |
| 73 | #endif |
| 74 | |
| 75 | /* This comment documents high-level logic of this file. |
| 76 | |
| 77 | Waiting for events in sync mode |
| 78 | =============================== |
| 79 | |
| 80 | When waiting for an event in a specific thread, we just use waitpid, |
| 81 | passing the specific pid, and not passing WNOHANG. |
| 82 | |
| 83 | When waiting for an event in all threads, waitpid is not quite good: |
| 84 | |
| 85 | - If the thread group leader exits while other threads in the thread |
| 86 | group still exist, waitpid(TGID, ...) hangs. That waitpid won't |
| 87 | return an exit status until the other threads in the group are |
| 88 | reaped. |
| 89 | |
| 90 | - When a non-leader thread execs, that thread just vanishes without |
| 91 | reporting an exit (so we'd hang if we waited for it explicitly in |
| 92 | that case). The exec event is instead reported to the TGID pid. |
| 93 | |
| 94 | The solution is to always use -1 and WNOHANG, together with |
| 95 | sigsuspend. |
| 96 | |
| 97 | First, we use non-blocking waitpid to check for events. If nothing is |
| 98 | found, we use sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, |
| 99 | it means something happened to a child process. As soon as we know |
| 100 | there's an event, we get back to calling nonblocking waitpid. |
| 101 | |
| 102 | Note that SIGCHLD should be blocked between waitpid and sigsuspend |
| 103 | calls, so that we don't miss a signal. If SIGCHLD arrives in between, |
| 104 | when it's blocked, the signal becomes pending and sigsuspend |
| 105 | immediately notices it and returns. |
| 106 | |
| 107 | Waiting for events in async mode (TARGET_WNOHANG) |
| 108 | ================================================= |
| 109 | |
| 110 | In async mode, GDB should always be ready to handle both user input |
| 111 | and target events, so neither blocking waitpid nor sigsuspend are |
| 112 | viable options. Instead, we should asynchronously notify the GDB main |
| 113 | event loop whenever there's an unprocessed event from the target. We |
| 114 | detect asynchronous target events by handling SIGCHLD signals. To |
| 115 | notify the event loop about target events, the self-pipe trick is used |
| 116 | --- a pipe is registered as waitable event source in the event loop, |
| 117 | the event loop select/poll's on the read end of this pipe (as well on |
| 118 | other event sources, e.g., stdin), and the SIGCHLD handler writes a |
| 119 | byte to this pipe. This is more portable than relying on |
| 120 | pselect/ppoll, since on kernels that lack those syscalls, libc |
| 121 | emulates them with select/poll+sigprocmask, and that is racy |
| 122 | (a.k.a. plain broken). |
| 123 | |
| 124 | Obviously, if we fail to notify the event loop if there's a target |
| 125 | event, it's bad. OTOH, if we notify the event loop when there's no |
| 126 | event from the target, linux_nat_wait will detect that there's no real |
| 127 | event to report, and return event of type TARGET_WAITKIND_IGNORE. |
| 128 | This is mostly harmless, but it will waste time and is better avoided. |
| 129 | |
| 130 | The main design point is that every time GDB is outside linux-nat.c, |
| 131 | we have a SIGCHLD handler installed that is called when something |
| 132 | happens to the target and notifies the GDB event loop. Whenever GDB |
| 133 | core decides to handle the event, and calls into linux-nat.c, we |
| 134 | process things as in sync mode, except that the we never block in |
| 135 | sigsuspend. |
| 136 | |
| 137 | While processing an event, we may end up momentarily blocked in |
| 138 | waitpid calls. Those waitpid calls, while blocking, are guarantied to |
| 139 | return quickly. E.g., in all-stop mode, before reporting to the core |
| 140 | that an LWP hit a breakpoint, all LWPs are stopped by sending them |
| 141 | SIGSTOP, and synchronously waiting for the SIGSTOP to be reported. |
| 142 | Note that this is different from blocking indefinitely waiting for the |
| 143 | next event --- here, we're already handling an event. |
| 144 | |
| 145 | Use of signals |
| 146 | ============== |
| 147 | |
| 148 | We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another |
| 149 | signal is not entirely significant; we just need for a signal to be delivered, |
| 150 | so that we can intercept it. SIGSTOP's advantage is that it can not be |
| 151 | blocked. A disadvantage is that it is not a real-time signal, so it can only |
| 152 | be queued once; we do not keep track of other sources of SIGSTOP. |
| 153 | |
| 154 | Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't |
| 155 | use them, because they have special behavior when the signal is generated - |
| 156 | not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL |
| 157 | kills the entire thread group. |
| 158 | |
| 159 | A delivered SIGSTOP would stop the entire thread group, not just the thread we |
| 160 | tkill'd. But we never let the SIGSTOP be delivered; we always intercept and |
| 161 | cancel it (by PTRACE_CONT without passing SIGSTOP). |
| 162 | |
| 163 | We could use a real-time signal instead. This would solve those problems; we |
| 164 | could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB. |
| 165 | But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH |
| 166 | generates it, and there are races with trying to find a signal that is not |
| 167 | blocked. |
| 168 | |
| 169 | Exec events |
| 170 | =========== |
| 171 | |
| 172 | The case of a thread group (process) with 3 or more threads, and a |
| 173 | thread other than the leader execs is worth detailing: |
| 174 | |
| 175 | On an exec, the Linux kernel destroys all threads except the execing |
| 176 | one in the thread group, and resets the execing thread's tid to the |
| 177 | tgid. No exit notification is sent for the execing thread -- from the |
| 178 | ptracer's perspective, it appears as though the execing thread just |
| 179 | vanishes. Until we reap all other threads except the leader and the |
| 180 | execing thread, the leader will be zombie, and the execing thread will |
| 181 | be in `D (disc sleep)' state. As soon as all other threads are |
| 182 | reaped, the execing thread changes its tid to the tgid, and the |
| 183 | previous (zombie) leader vanishes, giving place to the "new" |
| 184 | leader. */ |
| 185 | |
| 186 | #ifndef O_LARGEFILE |
| 187 | #define O_LARGEFILE 0 |
| 188 | #endif |
| 189 | |
| 190 | struct linux_nat_target *linux_target; |
| 191 | |
| 192 | /* Does the current host support PTRACE_GETREGSET? */ |
| 193 | enum tribool have_ptrace_getregset = TRIBOOL_UNKNOWN; |
| 194 | |
| 195 | static unsigned int debug_linux_nat; |
| 196 | static void |
| 197 | show_debug_linux_nat (struct ui_file *file, int from_tty, |
| 198 | struct cmd_list_element *c, const char *value) |
| 199 | { |
| 200 | fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"), |
| 201 | value); |
| 202 | } |
| 203 | |
| 204 | struct simple_pid_list |
| 205 | { |
| 206 | int pid; |
| 207 | int status; |
| 208 | struct simple_pid_list *next; |
| 209 | }; |
| 210 | struct simple_pid_list *stopped_pids; |
| 211 | |
| 212 | /* Whether target_thread_events is in effect. */ |
| 213 | static int report_thread_events; |
| 214 | |
| 215 | /* Async mode support. */ |
| 216 | |
| 217 | /* The read/write ends of the pipe registered as waitable file in the |
| 218 | event loop. */ |
| 219 | static int linux_nat_event_pipe[2] = { -1, -1 }; |
| 220 | |
| 221 | /* True if we're currently in async mode. */ |
| 222 | #define linux_is_async_p() (linux_nat_event_pipe[0] != -1) |
| 223 | |
| 224 | /* Flush the event pipe. */ |
| 225 | |
| 226 | static void |
| 227 | async_file_flush (void) |
| 228 | { |
| 229 | int ret; |
| 230 | char buf; |
| 231 | |
| 232 | do |
| 233 | { |
| 234 | ret = read (linux_nat_event_pipe[0], &buf, 1); |
| 235 | } |
| 236 | while (ret >= 0 || (ret == -1 && errno == EINTR)); |
| 237 | } |
| 238 | |
| 239 | /* Put something (anything, doesn't matter what, or how much) in event |
| 240 | pipe, so that the select/poll in the event-loop realizes we have |
| 241 | something to process. */ |
| 242 | |
| 243 | static void |
| 244 | async_file_mark (void) |
| 245 | { |
| 246 | int ret; |
| 247 | |
| 248 | /* It doesn't really matter what the pipe contains, as long we end |
| 249 | up with something in it. Might as well flush the previous |
| 250 | left-overs. */ |
| 251 | async_file_flush (); |
| 252 | |
| 253 | do |
| 254 | { |
| 255 | ret = write (linux_nat_event_pipe[1], "+", 1); |
| 256 | } |
| 257 | while (ret == -1 && errno == EINTR); |
| 258 | |
| 259 | /* Ignore EAGAIN. If the pipe is full, the event loop will already |
| 260 | be awakened anyway. */ |
| 261 | } |
| 262 | |
| 263 | static int kill_lwp (int lwpid, int signo); |
| 264 | |
| 265 | static int stop_callback (struct lwp_info *lp); |
| 266 | |
| 267 | static void block_child_signals (sigset_t *prev_mask); |
| 268 | static void restore_child_signals_mask (sigset_t *prev_mask); |
| 269 | |
| 270 | struct lwp_info; |
| 271 | static struct lwp_info *add_lwp (ptid_t ptid); |
| 272 | static void purge_lwp_list (int pid); |
| 273 | static void delete_lwp (ptid_t ptid); |
| 274 | static struct lwp_info *find_lwp_pid (ptid_t ptid); |
| 275 | |
| 276 | static int lwp_status_pending_p (struct lwp_info *lp); |
| 277 | |
| 278 | static void save_stop_reason (struct lwp_info *lp); |
| 279 | |
| 280 | \f |
| 281 | /* LWP accessors. */ |
| 282 | |
| 283 | /* See nat/linux-nat.h. */ |
| 284 | |
| 285 | ptid_t |
| 286 | ptid_of_lwp (struct lwp_info *lwp) |
| 287 | { |
| 288 | return lwp->ptid; |
| 289 | } |
| 290 | |
| 291 | /* See nat/linux-nat.h. */ |
| 292 | |
| 293 | void |
| 294 | lwp_set_arch_private_info (struct lwp_info *lwp, |
| 295 | struct arch_lwp_info *info) |
| 296 | { |
| 297 | lwp->arch_private = info; |
| 298 | } |
| 299 | |
| 300 | /* See nat/linux-nat.h. */ |
| 301 | |
| 302 | struct arch_lwp_info * |
| 303 | lwp_arch_private_info (struct lwp_info *lwp) |
| 304 | { |
| 305 | return lwp->arch_private; |
| 306 | } |
| 307 | |
| 308 | /* See nat/linux-nat.h. */ |
| 309 | |
| 310 | int |
| 311 | lwp_is_stopped (struct lwp_info *lwp) |
| 312 | { |
| 313 | return lwp->stopped; |
| 314 | } |
| 315 | |
| 316 | /* See nat/linux-nat.h. */ |
| 317 | |
| 318 | enum target_stop_reason |
| 319 | lwp_stop_reason (struct lwp_info *lwp) |
| 320 | { |
| 321 | return lwp->stop_reason; |
| 322 | } |
| 323 | |
| 324 | /* See nat/linux-nat.h. */ |
| 325 | |
| 326 | int |
| 327 | lwp_is_stepping (struct lwp_info *lwp) |
| 328 | { |
| 329 | return lwp->step; |
| 330 | } |
| 331 | |
| 332 | \f |
| 333 | /* Trivial list manipulation functions to keep track of a list of |
| 334 | new stopped processes. */ |
| 335 | static void |
| 336 | add_to_pid_list (struct simple_pid_list **listp, int pid, int status) |
| 337 | { |
| 338 | struct simple_pid_list *new_pid = XNEW (struct simple_pid_list); |
| 339 | |
| 340 | new_pid->pid = pid; |
| 341 | new_pid->status = status; |
| 342 | new_pid->next = *listp; |
| 343 | *listp = new_pid; |
| 344 | } |
| 345 | |
| 346 | static int |
| 347 | pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp) |
| 348 | { |
| 349 | struct simple_pid_list **p; |
| 350 | |
| 351 | for (p = listp; *p != NULL; p = &(*p)->next) |
| 352 | if ((*p)->pid == pid) |
| 353 | { |
| 354 | struct simple_pid_list *next = (*p)->next; |
| 355 | |
| 356 | *statusp = (*p)->status; |
| 357 | xfree (*p); |
| 358 | *p = next; |
| 359 | return 1; |
| 360 | } |
| 361 | return 0; |
| 362 | } |
| 363 | |
| 364 | /* Return the ptrace options that we want to try to enable. */ |
| 365 | |
| 366 | static int |
| 367 | linux_nat_ptrace_options (int attached) |
| 368 | { |
| 369 | int options = 0; |
| 370 | |
| 371 | if (!attached) |
| 372 | options |= PTRACE_O_EXITKILL; |
| 373 | |
| 374 | options |= (PTRACE_O_TRACESYSGOOD |
| 375 | | PTRACE_O_TRACEVFORKDONE |
| 376 | | PTRACE_O_TRACEVFORK |
| 377 | | PTRACE_O_TRACEFORK |
| 378 | | PTRACE_O_TRACEEXEC); |
| 379 | |
| 380 | return options; |
| 381 | } |
| 382 | |
| 383 | /* Initialize ptrace and procfs warnings and check for supported |
| 384 | ptrace features given PID. |
| 385 | |
| 386 | ATTACHED should be nonzero iff we attached to the inferior. */ |
| 387 | |
| 388 | static void |
| 389 | linux_init_ptrace_procfs (pid_t pid, int attached) |
| 390 | { |
| 391 | int options = linux_nat_ptrace_options (attached); |
| 392 | |
| 393 | linux_enable_event_reporting (pid, options); |
| 394 | linux_ptrace_init_warnings (); |
| 395 | linux_proc_init_warnings (); |
| 396 | } |
| 397 | |
| 398 | linux_nat_target::~linux_nat_target () |
| 399 | {} |
| 400 | |
| 401 | void |
| 402 | linux_nat_target::post_attach (int pid) |
| 403 | { |
| 404 | linux_init_ptrace_procfs (pid, 1); |
| 405 | } |
| 406 | |
| 407 | void |
| 408 | linux_nat_target::post_startup_inferior (ptid_t ptid) |
| 409 | { |
| 410 | linux_init_ptrace_procfs (ptid.pid (), 0); |
| 411 | } |
| 412 | |
| 413 | /* Return the number of known LWPs in the tgid given by PID. */ |
| 414 | |
| 415 | static int |
| 416 | num_lwps (int pid) |
| 417 | { |
| 418 | int count = 0; |
| 419 | struct lwp_info *lp; |
| 420 | |
| 421 | for (lp = lwp_list; lp; lp = lp->next) |
| 422 | if (lp->ptid.pid () == pid) |
| 423 | count++; |
| 424 | |
| 425 | return count; |
| 426 | } |
| 427 | |
| 428 | /* Deleter for lwp_info unique_ptr specialisation. */ |
| 429 | |
| 430 | struct lwp_deleter |
| 431 | { |
| 432 | void operator() (struct lwp_info *lwp) const |
| 433 | { |
| 434 | delete_lwp (lwp->ptid); |
| 435 | } |
| 436 | }; |
| 437 | |
| 438 | /* A unique_ptr specialisation for lwp_info. */ |
| 439 | |
| 440 | typedef std::unique_ptr<struct lwp_info, lwp_deleter> lwp_info_up; |
| 441 | |
| 442 | /* Target hook for follow_fork. On entry inferior_ptid must be the |
| 443 | ptid of the followed inferior. At return, inferior_ptid will be |
| 444 | unchanged. */ |
| 445 | |
| 446 | int |
| 447 | linux_nat_target::follow_fork (int follow_child, int detach_fork) |
| 448 | { |
| 449 | if (!follow_child) |
| 450 | { |
| 451 | struct lwp_info *child_lp = NULL; |
| 452 | int has_vforked; |
| 453 | ptid_t parent_ptid, child_ptid; |
| 454 | int parent_pid, child_pid; |
| 455 | |
| 456 | has_vforked = (inferior_thread ()->pending_follow.kind |
| 457 | == TARGET_WAITKIND_VFORKED); |
| 458 | parent_ptid = inferior_ptid; |
| 459 | child_ptid = inferior_thread ()->pending_follow.value.related_pid; |
| 460 | parent_pid = parent_ptid.lwp (); |
| 461 | child_pid = child_ptid.lwp (); |
| 462 | |
| 463 | /* We're already attached to the parent, by default. */ |
| 464 | child_lp = add_lwp (child_ptid); |
| 465 | child_lp->stopped = 1; |
| 466 | child_lp->last_resume_kind = resume_stop; |
| 467 | |
| 468 | /* Detach new forked process? */ |
| 469 | if (detach_fork) |
| 470 | { |
| 471 | int child_stop_signal = 0; |
| 472 | bool detach_child = true; |
| 473 | |
| 474 | /* Move CHILD_LP into a unique_ptr and clear the source pointer |
| 475 | to prevent us doing anything stupid with it. */ |
| 476 | lwp_info_up child_lp_ptr (child_lp); |
| 477 | child_lp = nullptr; |
| 478 | |
| 479 | linux_target->low_prepare_to_resume (child_lp_ptr.get ()); |
| 480 | |
| 481 | /* When debugging an inferior in an architecture that supports |
| 482 | hardware single stepping on a kernel without commit |
| 483 | 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child |
| 484 | process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits |
| 485 | set if the parent process had them set. |
| 486 | To work around this, single step the child process |
| 487 | once before detaching to clear the flags. */ |
| 488 | |
| 489 | /* Note that we consult the parent's architecture instead of |
| 490 | the child's because there's no inferior for the child at |
| 491 | this point. */ |
| 492 | if (!gdbarch_software_single_step_p (target_thread_architecture |
| 493 | (parent_ptid))) |
| 494 | { |
| 495 | int status; |
| 496 | |
| 497 | linux_disable_event_reporting (child_pid); |
| 498 | if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0) |
| 499 | perror_with_name (_("Couldn't do single step")); |
| 500 | if (my_waitpid (child_pid, &status, 0) < 0) |
| 501 | perror_with_name (_("Couldn't wait vfork process")); |
| 502 | else |
| 503 | { |
| 504 | detach_child = WIFSTOPPED (status); |
| 505 | child_stop_signal = WSTOPSIG (status); |
| 506 | } |
| 507 | } |
| 508 | |
| 509 | if (detach_child) |
| 510 | { |
| 511 | int signo = child_stop_signal; |
| 512 | |
| 513 | if (signo != 0 |
| 514 | && !signal_pass_state (gdb_signal_from_host (signo))) |
| 515 | signo = 0; |
| 516 | ptrace (PTRACE_DETACH, child_pid, 0, signo); |
| 517 | } |
| 518 | } |
| 519 | else |
| 520 | { |
| 521 | scoped_restore save_inferior_ptid |
| 522 | = make_scoped_restore (&inferior_ptid); |
| 523 | inferior_ptid = child_ptid; |
| 524 | |
| 525 | /* Let the thread_db layer learn about this new process. */ |
| 526 | check_for_thread_db (); |
| 527 | } |
| 528 | |
| 529 | if (has_vforked) |
| 530 | { |
| 531 | struct lwp_info *parent_lp; |
| 532 | |
| 533 | parent_lp = find_lwp_pid (parent_ptid); |
| 534 | gdb_assert (linux_supports_tracefork () >= 0); |
| 535 | |
| 536 | if (linux_supports_tracevforkdone ()) |
| 537 | { |
| 538 | if (debug_linux_nat) |
| 539 | fprintf_unfiltered (gdb_stdlog, |
| 540 | "LCFF: waiting for VFORK_DONE on %d\n", |
| 541 | parent_pid); |
| 542 | parent_lp->stopped = 1; |
| 543 | |
| 544 | /* We'll handle the VFORK_DONE event like any other |
| 545 | event, in target_wait. */ |
| 546 | } |
| 547 | else |
| 548 | { |
| 549 | /* We can't insert breakpoints until the child has |
| 550 | finished with the shared memory region. We need to |
| 551 | wait until that happens. Ideal would be to just |
| 552 | call: |
| 553 | - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0); |
| 554 | - waitpid (parent_pid, &status, __WALL); |
| 555 | However, most architectures can't handle a syscall |
| 556 | being traced on the way out if it wasn't traced on |
| 557 | the way in. |
| 558 | |
| 559 | We might also think to loop, continuing the child |
| 560 | until it exits or gets a SIGTRAP. One problem is |
| 561 | that the child might call ptrace with PTRACE_TRACEME. |
| 562 | |
| 563 | There's no simple and reliable way to figure out when |
| 564 | the vforked child will be done with its copy of the |
| 565 | shared memory. We could step it out of the syscall, |
| 566 | two instructions, let it go, and then single-step the |
| 567 | parent once. When we have hardware single-step, this |
| 568 | would work; with software single-step it could still |
| 569 | be made to work but we'd have to be able to insert |
| 570 | single-step breakpoints in the child, and we'd have |
| 571 | to insert -just- the single-step breakpoint in the |
| 572 | parent. Very awkward. |
| 573 | |
| 574 | In the end, the best we can do is to make sure it |
| 575 | runs for a little while. Hopefully it will be out of |
| 576 | range of any breakpoints we reinsert. Usually this |
| 577 | is only the single-step breakpoint at vfork's return |
| 578 | point. */ |
| 579 | |
| 580 | if (debug_linux_nat) |
| 581 | fprintf_unfiltered (gdb_stdlog, |
| 582 | "LCFF: no VFORK_DONE " |
| 583 | "support, sleeping a bit\n"); |
| 584 | |
| 585 | usleep (10000); |
| 586 | |
| 587 | /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event, |
| 588 | and leave it pending. The next linux_nat_resume call |
| 589 | will notice a pending event, and bypasses actually |
| 590 | resuming the inferior. */ |
| 591 | parent_lp->status = 0; |
| 592 | parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE; |
| 593 | parent_lp->stopped = 1; |
| 594 | |
| 595 | /* If we're in async mode, need to tell the event loop |
| 596 | there's something here to process. */ |
| 597 | if (target_is_async_p ()) |
| 598 | async_file_mark (); |
| 599 | } |
| 600 | } |
| 601 | } |
| 602 | else |
| 603 | { |
| 604 | struct lwp_info *child_lp; |
| 605 | |
| 606 | child_lp = add_lwp (inferior_ptid); |
| 607 | child_lp->stopped = 1; |
| 608 | child_lp->last_resume_kind = resume_stop; |
| 609 | |
| 610 | /* Let the thread_db layer learn about this new process. */ |
| 611 | check_for_thread_db (); |
| 612 | } |
| 613 | |
| 614 | return 0; |
| 615 | } |
| 616 | |
| 617 | \f |
| 618 | int |
| 619 | linux_nat_target::insert_fork_catchpoint (int pid) |
| 620 | { |
| 621 | return !linux_supports_tracefork (); |
| 622 | } |
| 623 | |
| 624 | int |
| 625 | linux_nat_target::remove_fork_catchpoint (int pid) |
| 626 | { |
| 627 | return 0; |
| 628 | } |
| 629 | |
| 630 | int |
| 631 | linux_nat_target::insert_vfork_catchpoint (int pid) |
| 632 | { |
| 633 | return !linux_supports_tracefork (); |
| 634 | } |
| 635 | |
| 636 | int |
| 637 | linux_nat_target::remove_vfork_catchpoint (int pid) |
| 638 | { |
| 639 | return 0; |
| 640 | } |
| 641 | |
| 642 | int |
| 643 | linux_nat_target::insert_exec_catchpoint (int pid) |
| 644 | { |
| 645 | return !linux_supports_tracefork (); |
| 646 | } |
| 647 | |
| 648 | int |
| 649 | linux_nat_target::remove_exec_catchpoint (int pid) |
| 650 | { |
| 651 | return 0; |
| 652 | } |
| 653 | |
| 654 | int |
| 655 | linux_nat_target::set_syscall_catchpoint (int pid, bool needed, int any_count, |
| 656 | gdb::array_view<const int> syscall_counts) |
| 657 | { |
| 658 | if (!linux_supports_tracesysgood ()) |
| 659 | return 1; |
| 660 | |
| 661 | /* On GNU/Linux, we ignore the arguments. It means that we only |
| 662 | enable the syscall catchpoints, but do not disable them. |
| 663 | |
| 664 | Also, we do not use the `syscall_counts' information because we do not |
| 665 | filter system calls here. We let GDB do the logic for us. */ |
| 666 | return 0; |
| 667 | } |
| 668 | |
| 669 | /* List of known LWPs, keyed by LWP PID. This speeds up the common |
| 670 | case of mapping a PID returned from the kernel to our corresponding |
| 671 | lwp_info data structure. */ |
| 672 | static htab_t lwp_lwpid_htab; |
| 673 | |
| 674 | /* Calculate a hash from a lwp_info's LWP PID. */ |
| 675 | |
| 676 | static hashval_t |
| 677 | lwp_info_hash (const void *ap) |
| 678 | { |
| 679 | const struct lwp_info *lp = (struct lwp_info *) ap; |
| 680 | pid_t pid = lp->ptid.lwp (); |
| 681 | |
| 682 | return iterative_hash_object (pid, 0); |
| 683 | } |
| 684 | |
| 685 | /* Equality function for the lwp_info hash table. Compares the LWP's |
| 686 | PID. */ |
| 687 | |
| 688 | static int |
| 689 | lwp_lwpid_htab_eq (const void *a, const void *b) |
| 690 | { |
| 691 | const struct lwp_info *entry = (const struct lwp_info *) a; |
| 692 | const struct lwp_info *element = (const struct lwp_info *) b; |
| 693 | |
| 694 | return entry->ptid.lwp () == element->ptid.lwp (); |
| 695 | } |
| 696 | |
| 697 | /* Create the lwp_lwpid_htab hash table. */ |
| 698 | |
| 699 | static void |
| 700 | lwp_lwpid_htab_create (void) |
| 701 | { |
| 702 | lwp_lwpid_htab = htab_create (100, lwp_info_hash, lwp_lwpid_htab_eq, NULL); |
| 703 | } |
| 704 | |
| 705 | /* Add LP to the hash table. */ |
| 706 | |
| 707 | static void |
| 708 | lwp_lwpid_htab_add_lwp (struct lwp_info *lp) |
| 709 | { |
| 710 | void **slot; |
| 711 | |
| 712 | slot = htab_find_slot (lwp_lwpid_htab, lp, INSERT); |
| 713 | gdb_assert (slot != NULL && *slot == NULL); |
| 714 | *slot = lp; |
| 715 | } |
| 716 | |
| 717 | /* Head of doubly-linked list of known LWPs. Sorted by reverse |
| 718 | creation order. This order is assumed in some cases. E.g., |
| 719 | reaping status after killing alls lwps of a process: the leader LWP |
| 720 | must be reaped last. */ |
| 721 | struct lwp_info *lwp_list; |
| 722 | |
| 723 | /* Add LP to sorted-by-reverse-creation-order doubly-linked list. */ |
| 724 | |
| 725 | static void |
| 726 | lwp_list_add (struct lwp_info *lp) |
| 727 | { |
| 728 | lp->next = lwp_list; |
| 729 | if (lwp_list != NULL) |
| 730 | lwp_list->prev = lp; |
| 731 | lwp_list = lp; |
| 732 | } |
| 733 | |
| 734 | /* Remove LP from sorted-by-reverse-creation-order doubly-linked |
| 735 | list. */ |
| 736 | |
| 737 | static void |
| 738 | lwp_list_remove (struct lwp_info *lp) |
| 739 | { |
| 740 | /* Remove from sorted-by-creation-order list. */ |
| 741 | if (lp->next != NULL) |
| 742 | lp->next->prev = lp->prev; |
| 743 | if (lp->prev != NULL) |
| 744 | lp->prev->next = lp->next; |
| 745 | if (lp == lwp_list) |
| 746 | lwp_list = lp->next; |
| 747 | } |
| 748 | |
| 749 | \f |
| 750 | |
| 751 | /* Original signal mask. */ |
| 752 | static sigset_t normal_mask; |
| 753 | |
| 754 | /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in |
| 755 | _initialize_linux_nat. */ |
| 756 | static sigset_t suspend_mask; |
| 757 | |
| 758 | /* Signals to block to make that sigsuspend work. */ |
| 759 | static sigset_t blocked_mask; |
| 760 | |
| 761 | /* SIGCHLD action. */ |
| 762 | struct sigaction sigchld_action; |
| 763 | |
| 764 | /* Block child signals (SIGCHLD and linux threads signals), and store |
| 765 | the previous mask in PREV_MASK. */ |
| 766 | |
| 767 | static void |
| 768 | block_child_signals (sigset_t *prev_mask) |
| 769 | { |
| 770 | /* Make sure SIGCHLD is blocked. */ |
| 771 | if (!sigismember (&blocked_mask, SIGCHLD)) |
| 772 | sigaddset (&blocked_mask, SIGCHLD); |
| 773 | |
| 774 | sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask); |
| 775 | } |
| 776 | |
| 777 | /* Restore child signals mask, previously returned by |
| 778 | block_child_signals. */ |
| 779 | |
| 780 | static void |
| 781 | restore_child_signals_mask (sigset_t *prev_mask) |
| 782 | { |
| 783 | sigprocmask (SIG_SETMASK, prev_mask, NULL); |
| 784 | } |
| 785 | |
| 786 | /* Mask of signals to pass directly to the inferior. */ |
| 787 | static sigset_t pass_mask; |
| 788 | |
| 789 | /* Update signals to pass to the inferior. */ |
| 790 | void |
| 791 | linux_nat_target::pass_signals |
| 792 | (gdb::array_view<const unsigned char> pass_signals) |
| 793 | { |
| 794 | int signo; |
| 795 | |
| 796 | sigemptyset (&pass_mask); |
| 797 | |
| 798 | for (signo = 1; signo < NSIG; signo++) |
| 799 | { |
| 800 | int target_signo = gdb_signal_from_host (signo); |
| 801 | if (target_signo < pass_signals.size () && pass_signals[target_signo]) |
| 802 | sigaddset (&pass_mask, signo); |
| 803 | } |
| 804 | } |
| 805 | |
| 806 | \f |
| 807 | |
| 808 | /* Prototypes for local functions. */ |
| 809 | static int stop_wait_callback (struct lwp_info *lp); |
| 810 | static int resume_stopped_resumed_lwps (struct lwp_info *lp, const ptid_t wait_ptid); |
| 811 | static int check_ptrace_stopped_lwp_gone (struct lwp_info *lp); |
| 812 | |
| 813 | \f |
| 814 | |
| 815 | /* Destroy and free LP. */ |
| 816 | |
| 817 | static void |
| 818 | lwp_free (struct lwp_info *lp) |
| 819 | { |
| 820 | /* Let the arch specific bits release arch_lwp_info. */ |
| 821 | linux_target->low_delete_thread (lp->arch_private); |
| 822 | |
| 823 | xfree (lp); |
| 824 | } |
| 825 | |
| 826 | /* Traversal function for purge_lwp_list. */ |
| 827 | |
| 828 | static int |
| 829 | lwp_lwpid_htab_remove_pid (void **slot, void *info) |
| 830 | { |
| 831 | struct lwp_info *lp = (struct lwp_info *) *slot; |
| 832 | int pid = *(int *) info; |
| 833 | |
| 834 | if (lp->ptid.pid () == pid) |
| 835 | { |
| 836 | htab_clear_slot (lwp_lwpid_htab, slot); |
| 837 | lwp_list_remove (lp); |
| 838 | lwp_free (lp); |
| 839 | } |
| 840 | |
| 841 | return 1; |
| 842 | } |
| 843 | |
| 844 | /* Remove all LWPs belong to PID from the lwp list. */ |
| 845 | |
| 846 | static void |
| 847 | purge_lwp_list (int pid) |
| 848 | { |
| 849 | htab_traverse_noresize (lwp_lwpid_htab, lwp_lwpid_htab_remove_pid, &pid); |
| 850 | } |
| 851 | |
| 852 | /* Add the LWP specified by PTID to the list. PTID is the first LWP |
| 853 | in the process. Return a pointer to the structure describing the |
| 854 | new LWP. |
| 855 | |
| 856 | This differs from add_lwp in that we don't let the arch specific |
| 857 | bits know about this new thread. Current clients of this callback |
| 858 | take the opportunity to install watchpoints in the new thread, and |
| 859 | we shouldn't do that for the first thread. If we're spawning a |
| 860 | child ("run"), the thread executes the shell wrapper first, and we |
| 861 | shouldn't touch it until it execs the program we want to debug. |
| 862 | For "attach", it'd be okay to call the callback, but it's not |
| 863 | necessary, because watchpoints can't yet have been inserted into |
| 864 | the inferior. */ |
| 865 | |
| 866 | static struct lwp_info * |
| 867 | add_initial_lwp (ptid_t ptid) |
| 868 | { |
| 869 | struct lwp_info *lp; |
| 870 | |
| 871 | gdb_assert (ptid.lwp_p ()); |
| 872 | |
| 873 | lp = XNEW (struct lwp_info); |
| 874 | |
| 875 | memset (lp, 0, sizeof (struct lwp_info)); |
| 876 | |
| 877 | lp->last_resume_kind = resume_continue; |
| 878 | lp->waitstatus.kind = TARGET_WAITKIND_IGNORE; |
| 879 | |
| 880 | lp->ptid = ptid; |
| 881 | lp->core = -1; |
| 882 | |
| 883 | /* Add to sorted-by-reverse-creation-order list. */ |
| 884 | lwp_list_add (lp); |
| 885 | |
| 886 | /* Add to keyed-by-pid htab. */ |
| 887 | lwp_lwpid_htab_add_lwp (lp); |
| 888 | |
| 889 | return lp; |
| 890 | } |
| 891 | |
| 892 | /* Add the LWP specified by PID to the list. Return a pointer to the |
| 893 | structure describing the new LWP. The LWP should already be |
| 894 | stopped. */ |
| 895 | |
| 896 | static struct lwp_info * |
| 897 | add_lwp (ptid_t ptid) |
| 898 | { |
| 899 | struct lwp_info *lp; |
| 900 | |
| 901 | lp = add_initial_lwp (ptid); |
| 902 | |
| 903 | /* Let the arch specific bits know about this new thread. Current |
| 904 | clients of this callback take the opportunity to install |
| 905 | watchpoints in the new thread. We don't do this for the first |
| 906 | thread though. See add_initial_lwp. */ |
| 907 | linux_target->low_new_thread (lp); |
| 908 | |
| 909 | return lp; |
| 910 | } |
| 911 | |
| 912 | /* Remove the LWP specified by PID from the list. */ |
| 913 | |
| 914 | static void |
| 915 | delete_lwp (ptid_t ptid) |
| 916 | { |
| 917 | struct lwp_info *lp; |
| 918 | void **slot; |
| 919 | struct lwp_info dummy; |
| 920 | |
| 921 | dummy.ptid = ptid; |
| 922 | slot = htab_find_slot (lwp_lwpid_htab, &dummy, NO_INSERT); |
| 923 | if (slot == NULL) |
| 924 | return; |
| 925 | |
| 926 | lp = *(struct lwp_info **) slot; |
| 927 | gdb_assert (lp != NULL); |
| 928 | |
| 929 | htab_clear_slot (lwp_lwpid_htab, slot); |
| 930 | |
| 931 | /* Remove from sorted-by-creation-order list. */ |
| 932 | lwp_list_remove (lp); |
| 933 | |
| 934 | /* Release. */ |
| 935 | lwp_free (lp); |
| 936 | } |
| 937 | |
| 938 | /* Return a pointer to the structure describing the LWP corresponding |
| 939 | to PID. If no corresponding LWP could be found, return NULL. */ |
| 940 | |
| 941 | static struct lwp_info * |
| 942 | find_lwp_pid (ptid_t ptid) |
| 943 | { |
| 944 | struct lwp_info *lp; |
| 945 | int lwp; |
| 946 | struct lwp_info dummy; |
| 947 | |
| 948 | if (ptid.lwp_p ()) |
| 949 | lwp = ptid.lwp (); |
| 950 | else |
| 951 | lwp = ptid.pid (); |
| 952 | |
| 953 | dummy.ptid = ptid_t (0, lwp, 0); |
| 954 | lp = (struct lwp_info *) htab_find (lwp_lwpid_htab, &dummy); |
| 955 | return lp; |
| 956 | } |
| 957 | |
| 958 | /* See nat/linux-nat.h. */ |
| 959 | |
| 960 | struct lwp_info * |
| 961 | iterate_over_lwps (ptid_t filter, |
| 962 | gdb::function_view<iterate_over_lwps_ftype> callback) |
| 963 | { |
| 964 | struct lwp_info *lp, *lpnext; |
| 965 | |
| 966 | for (lp = lwp_list; lp; lp = lpnext) |
| 967 | { |
| 968 | lpnext = lp->next; |
| 969 | |
| 970 | if (lp->ptid.matches (filter)) |
| 971 | { |
| 972 | if (callback (lp) != 0) |
| 973 | return lp; |
| 974 | } |
| 975 | } |
| 976 | |
| 977 | return NULL; |
| 978 | } |
| 979 | |
| 980 | /* Update our internal state when changing from one checkpoint to |
| 981 | another indicated by NEW_PTID. We can only switch single-threaded |
| 982 | applications, so we only create one new LWP, and the previous list |
| 983 | is discarded. */ |
| 984 | |
| 985 | void |
| 986 | linux_nat_switch_fork (ptid_t new_ptid) |
| 987 | { |
| 988 | struct lwp_info *lp; |
| 989 | |
| 990 | purge_lwp_list (inferior_ptid.pid ()); |
| 991 | |
| 992 | lp = add_lwp (new_ptid); |
| 993 | lp->stopped = 1; |
| 994 | |
| 995 | /* This changes the thread's ptid while preserving the gdb thread |
| 996 | num. Also changes the inferior pid, while preserving the |
| 997 | inferior num. */ |
| 998 | thread_change_ptid (inferior_ptid, new_ptid); |
| 999 | |
| 1000 | /* We've just told GDB core that the thread changed target id, but, |
| 1001 | in fact, it really is a different thread, with different register |
| 1002 | contents. */ |
| 1003 | registers_changed (); |
| 1004 | } |
| 1005 | |
| 1006 | /* Handle the exit of a single thread LP. */ |
| 1007 | |
| 1008 | static void |
| 1009 | exit_lwp (struct lwp_info *lp) |
| 1010 | { |
| 1011 | struct thread_info *th = find_thread_ptid (lp->ptid); |
| 1012 | |
| 1013 | if (th) |
| 1014 | { |
| 1015 | if (print_thread_events) |
| 1016 | printf_unfiltered (_("[%s exited]\n"), |
| 1017 | target_pid_to_str (lp->ptid).c_str ()); |
| 1018 | |
| 1019 | delete_thread (th); |
| 1020 | } |
| 1021 | |
| 1022 | delete_lwp (lp->ptid); |
| 1023 | } |
| 1024 | |
| 1025 | /* Wait for the LWP specified by LP, which we have just attached to. |
| 1026 | Returns a wait status for that LWP, to cache. */ |
| 1027 | |
| 1028 | static int |
| 1029 | linux_nat_post_attach_wait (ptid_t ptid, int *signalled) |
| 1030 | { |
| 1031 | pid_t new_pid, pid = ptid.lwp (); |
| 1032 | int status; |
| 1033 | |
| 1034 | if (linux_proc_pid_is_stopped (pid)) |
| 1035 | { |
| 1036 | if (debug_linux_nat) |
| 1037 | fprintf_unfiltered (gdb_stdlog, |
| 1038 | "LNPAW: Attaching to a stopped process\n"); |
| 1039 | |
| 1040 | /* The process is definitely stopped. It is in a job control |
| 1041 | stop, unless the kernel predates the TASK_STOPPED / |
| 1042 | TASK_TRACED distinction, in which case it might be in a |
| 1043 | ptrace stop. Make sure it is in a ptrace stop; from there we |
| 1044 | can kill it, signal it, et cetera. |
| 1045 | |
| 1046 | First make sure there is a pending SIGSTOP. Since we are |
| 1047 | already attached, the process can not transition from stopped |
| 1048 | to running without a PTRACE_CONT; so we know this signal will |
| 1049 | go into the queue. The SIGSTOP generated by PTRACE_ATTACH is |
| 1050 | probably already in the queue (unless this kernel is old |
| 1051 | enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP |
| 1052 | is not an RT signal, it can only be queued once. */ |
| 1053 | kill_lwp (pid, SIGSTOP); |
| 1054 | |
| 1055 | /* Finally, resume the stopped process. This will deliver the SIGSTOP |
| 1056 | (or a higher priority signal, just like normal PTRACE_ATTACH). */ |
| 1057 | ptrace (PTRACE_CONT, pid, 0, 0); |
| 1058 | } |
| 1059 | |
| 1060 | /* Make sure the initial process is stopped. The user-level threads |
| 1061 | layer might want to poke around in the inferior, and that won't |
| 1062 | work if things haven't stabilized yet. */ |
| 1063 | new_pid = my_waitpid (pid, &status, __WALL); |
| 1064 | gdb_assert (pid == new_pid); |
| 1065 | |
| 1066 | if (!WIFSTOPPED (status)) |
| 1067 | { |
| 1068 | /* The pid we tried to attach has apparently just exited. */ |
| 1069 | if (debug_linux_nat) |
| 1070 | fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s", |
| 1071 | pid, status_to_str (status)); |
| 1072 | return status; |
| 1073 | } |
| 1074 | |
| 1075 | if (WSTOPSIG (status) != SIGSTOP) |
| 1076 | { |
| 1077 | *signalled = 1; |
| 1078 | if (debug_linux_nat) |
| 1079 | fprintf_unfiltered (gdb_stdlog, |
| 1080 | "LNPAW: Received %s after attaching\n", |
| 1081 | status_to_str (status)); |
| 1082 | } |
| 1083 | |
| 1084 | return status; |
| 1085 | } |
| 1086 | |
| 1087 | void |
| 1088 | linux_nat_target::create_inferior (const char *exec_file, |
| 1089 | const std::string &allargs, |
| 1090 | char **env, int from_tty) |
| 1091 | { |
| 1092 | maybe_disable_address_space_randomization restore_personality |
| 1093 | (disable_randomization); |
| 1094 | |
| 1095 | /* The fork_child mechanism is synchronous and calls target_wait, so |
| 1096 | we have to mask the async mode. */ |
| 1097 | |
| 1098 | /* Make sure we report all signals during startup. */ |
| 1099 | pass_signals ({}); |
| 1100 | |
| 1101 | inf_ptrace_target::create_inferior (exec_file, allargs, env, from_tty); |
| 1102 | } |
| 1103 | |
| 1104 | /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not |
| 1105 | already attached. Returns true if a new LWP is found, false |
| 1106 | otherwise. */ |
| 1107 | |
| 1108 | static int |
| 1109 | attach_proc_task_lwp_callback (ptid_t ptid) |
| 1110 | { |
| 1111 | struct lwp_info *lp; |
| 1112 | |
| 1113 | /* Ignore LWPs we're already attached to. */ |
| 1114 | lp = find_lwp_pid (ptid); |
| 1115 | if (lp == NULL) |
| 1116 | { |
| 1117 | int lwpid = ptid.lwp (); |
| 1118 | |
| 1119 | if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0) |
| 1120 | { |
| 1121 | int err = errno; |
| 1122 | |
| 1123 | /* Be quiet if we simply raced with the thread exiting. |
| 1124 | EPERM is returned if the thread's task still exists, and |
| 1125 | is marked as exited or zombie, as well as other |
| 1126 | conditions, so in that case, confirm the status in |
| 1127 | /proc/PID/status. */ |
| 1128 | if (err == ESRCH |
| 1129 | || (err == EPERM && linux_proc_pid_is_gone (lwpid))) |
| 1130 | { |
| 1131 | if (debug_linux_nat) |
| 1132 | { |
| 1133 | fprintf_unfiltered (gdb_stdlog, |
| 1134 | "Cannot attach to lwp %d: " |
| 1135 | "thread is gone (%d: %s)\n", |
| 1136 | lwpid, err, safe_strerror (err)); |
| 1137 | } |
| 1138 | } |
| 1139 | else |
| 1140 | { |
| 1141 | std::string reason |
| 1142 | = linux_ptrace_attach_fail_reason_string (ptid, err); |
| 1143 | |
| 1144 | warning (_("Cannot attach to lwp %d: %s"), |
| 1145 | lwpid, reason.c_str ()); |
| 1146 | } |
| 1147 | } |
| 1148 | else |
| 1149 | { |
| 1150 | if (debug_linux_nat) |
| 1151 | fprintf_unfiltered (gdb_stdlog, |
| 1152 | "PTRACE_ATTACH %s, 0, 0 (OK)\n", |
| 1153 | target_pid_to_str (ptid).c_str ()); |
| 1154 | |
| 1155 | lp = add_lwp (ptid); |
| 1156 | |
| 1157 | /* The next time we wait for this LWP we'll see a SIGSTOP as |
| 1158 | PTRACE_ATTACH brings it to a halt. */ |
| 1159 | lp->signalled = 1; |
| 1160 | |
| 1161 | /* We need to wait for a stop before being able to make the |
| 1162 | next ptrace call on this LWP. */ |
| 1163 | lp->must_set_ptrace_flags = 1; |
| 1164 | |
| 1165 | /* So that wait collects the SIGSTOP. */ |
| 1166 | lp->resumed = 1; |
| 1167 | |
| 1168 | /* Also add the LWP to gdb's thread list, in case a |
| 1169 | matching libthread_db is not found (or the process uses |
| 1170 | raw clone). */ |
| 1171 | add_thread (lp->ptid); |
| 1172 | set_running (lp->ptid, 1); |
| 1173 | set_executing (lp->ptid, 1); |
| 1174 | } |
| 1175 | |
| 1176 | return 1; |
| 1177 | } |
| 1178 | return 0; |
| 1179 | } |
| 1180 | |
| 1181 | void |
| 1182 | linux_nat_target::attach (const char *args, int from_tty) |
| 1183 | { |
| 1184 | struct lwp_info *lp; |
| 1185 | int status; |
| 1186 | ptid_t ptid; |
| 1187 | |
| 1188 | /* Make sure we report all signals during attach. */ |
| 1189 | pass_signals ({}); |
| 1190 | |
| 1191 | try |
| 1192 | { |
| 1193 | inf_ptrace_target::attach (args, from_tty); |
| 1194 | } |
| 1195 | catch (const gdb_exception_error &ex) |
| 1196 | { |
| 1197 | pid_t pid = parse_pid_to_attach (args); |
| 1198 | std::string reason = linux_ptrace_attach_fail_reason (pid); |
| 1199 | |
| 1200 | if (!reason.empty ()) |
| 1201 | throw_error (ex.error, "warning: %s\n%s", reason.c_str (), |
| 1202 | ex.what ()); |
| 1203 | else |
| 1204 | throw_error (ex.error, "%s", ex.what ()); |
| 1205 | } |
| 1206 | |
| 1207 | /* The ptrace base target adds the main thread with (pid,0,0) |
| 1208 | format. Decorate it with lwp info. */ |
| 1209 | ptid = ptid_t (inferior_ptid.pid (), |
| 1210 | inferior_ptid.pid (), |
| 1211 | 0); |
| 1212 | thread_change_ptid (inferior_ptid, ptid); |
| 1213 | |
| 1214 | /* Add the initial process as the first LWP to the list. */ |
| 1215 | lp = add_initial_lwp (ptid); |
| 1216 | |
| 1217 | status = linux_nat_post_attach_wait (lp->ptid, &lp->signalled); |
| 1218 | if (!WIFSTOPPED (status)) |
| 1219 | { |
| 1220 | if (WIFEXITED (status)) |
| 1221 | { |
| 1222 | int exit_code = WEXITSTATUS (status); |
| 1223 | |
| 1224 | target_terminal::ours (); |
| 1225 | target_mourn_inferior (inferior_ptid); |
| 1226 | if (exit_code == 0) |
| 1227 | error (_("Unable to attach: program exited normally.")); |
| 1228 | else |
| 1229 | error (_("Unable to attach: program exited with code %d."), |
| 1230 | exit_code); |
| 1231 | } |
| 1232 | else if (WIFSIGNALED (status)) |
| 1233 | { |
| 1234 | enum gdb_signal signo; |
| 1235 | |
| 1236 | target_terminal::ours (); |
| 1237 | target_mourn_inferior (inferior_ptid); |
| 1238 | |
| 1239 | signo = gdb_signal_from_host (WTERMSIG (status)); |
| 1240 | error (_("Unable to attach: program terminated with signal " |
| 1241 | "%s, %s."), |
| 1242 | gdb_signal_to_name (signo), |
| 1243 | gdb_signal_to_string (signo)); |
| 1244 | } |
| 1245 | |
| 1246 | internal_error (__FILE__, __LINE__, |
| 1247 | _("unexpected status %d for PID %ld"), |
| 1248 | status, (long) ptid.lwp ()); |
| 1249 | } |
| 1250 | |
| 1251 | lp->stopped = 1; |
| 1252 | |
| 1253 | /* Save the wait status to report later. */ |
| 1254 | lp->resumed = 1; |
| 1255 | if (debug_linux_nat) |
| 1256 | fprintf_unfiltered (gdb_stdlog, |
| 1257 | "LNA: waitpid %ld, saving status %s\n", |
| 1258 | (long) lp->ptid.pid (), status_to_str (status)); |
| 1259 | |
| 1260 | lp->status = status; |
| 1261 | |
| 1262 | /* We must attach to every LWP. If /proc is mounted, use that to |
| 1263 | find them now. The inferior may be using raw clone instead of |
| 1264 | using pthreads. But even if it is using pthreads, thread_db |
| 1265 | walks structures in the inferior's address space to find the list |
| 1266 | of threads/LWPs, and those structures may well be corrupted. |
| 1267 | Note that once thread_db is loaded, we'll still use it to list |
| 1268 | threads and associate pthread info with each LWP. */ |
| 1269 | linux_proc_attach_tgid_threads (lp->ptid.pid (), |
| 1270 | attach_proc_task_lwp_callback); |
| 1271 | |
| 1272 | if (target_can_async_p ()) |
| 1273 | target_async (1); |
| 1274 | } |
| 1275 | |
| 1276 | /* Get pending signal of THREAD as a host signal number, for detaching |
| 1277 | purposes. This is the signal the thread last stopped for, which we |
| 1278 | need to deliver to the thread when detaching, otherwise, it'd be |
| 1279 | suppressed/lost. */ |
| 1280 | |
| 1281 | static int |
| 1282 | get_detach_signal (struct lwp_info *lp) |
| 1283 | { |
| 1284 | enum gdb_signal signo = GDB_SIGNAL_0; |
| 1285 | |
| 1286 | /* If we paused threads momentarily, we may have stored pending |
| 1287 | events in lp->status or lp->waitstatus (see stop_wait_callback), |
| 1288 | and GDB core hasn't seen any signal for those threads. |
| 1289 | Otherwise, the last signal reported to the core is found in the |
| 1290 | thread object's stop_signal. |
| 1291 | |
| 1292 | There's a corner case that isn't handled here at present. Only |
| 1293 | if the thread stopped with a TARGET_WAITKIND_STOPPED does |
| 1294 | stop_signal make sense as a real signal to pass to the inferior. |
| 1295 | Some catchpoint related events, like |
| 1296 | TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set |
| 1297 | to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But, |
| 1298 | those traps are debug API (ptrace in our case) related and |
| 1299 | induced; the inferior wouldn't see them if it wasn't being |
| 1300 | traced. Hence, we should never pass them to the inferior, even |
| 1301 | when set to pass state. Since this corner case isn't handled by |
| 1302 | infrun.c when proceeding with a signal, for consistency, neither |
| 1303 | do we handle it here (or elsewhere in the file we check for |
| 1304 | signal pass state). Normally SIGTRAP isn't set to pass state, so |
| 1305 | this is really a corner case. */ |
| 1306 | |
| 1307 | if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE) |
| 1308 | signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */ |
| 1309 | else if (lp->status) |
| 1310 | signo = gdb_signal_from_host (WSTOPSIG (lp->status)); |
| 1311 | else |
| 1312 | { |
| 1313 | struct thread_info *tp = find_thread_ptid (lp->ptid); |
| 1314 | |
| 1315 | if (target_is_non_stop_p () && !tp->executing) |
| 1316 | { |
| 1317 | if (tp->suspend.waitstatus_pending_p) |
| 1318 | signo = tp->suspend.waitstatus.value.sig; |
| 1319 | else |
| 1320 | signo = tp->suspend.stop_signal; |
| 1321 | } |
| 1322 | else if (!target_is_non_stop_p ()) |
| 1323 | { |
| 1324 | struct target_waitstatus last; |
| 1325 | ptid_t last_ptid; |
| 1326 | |
| 1327 | get_last_target_status (&last_ptid, &last); |
| 1328 | |
| 1329 | if (lp->ptid.lwp () == last_ptid.lwp ()) |
| 1330 | signo = tp->suspend.stop_signal; |
| 1331 | } |
| 1332 | } |
| 1333 | |
| 1334 | if (signo == GDB_SIGNAL_0) |
| 1335 | { |
| 1336 | if (debug_linux_nat) |
| 1337 | fprintf_unfiltered (gdb_stdlog, |
| 1338 | "GPT: lwp %s has no pending signal\n", |
| 1339 | target_pid_to_str (lp->ptid).c_str ()); |
| 1340 | } |
| 1341 | else if (!signal_pass_state (signo)) |
| 1342 | { |
| 1343 | if (debug_linux_nat) |
| 1344 | fprintf_unfiltered (gdb_stdlog, |
| 1345 | "GPT: lwp %s had signal %s, " |
| 1346 | "but it is in no pass state\n", |
| 1347 | target_pid_to_str (lp->ptid).c_str (), |
| 1348 | gdb_signal_to_string (signo)); |
| 1349 | } |
| 1350 | else |
| 1351 | { |
| 1352 | if (debug_linux_nat) |
| 1353 | fprintf_unfiltered (gdb_stdlog, |
| 1354 | "GPT: lwp %s has pending signal %s\n", |
| 1355 | target_pid_to_str (lp->ptid).c_str (), |
| 1356 | gdb_signal_to_string (signo)); |
| 1357 | |
| 1358 | return gdb_signal_to_host (signo); |
| 1359 | } |
| 1360 | |
| 1361 | return 0; |
| 1362 | } |
| 1363 | |
| 1364 | /* Detach from LP. If SIGNO_P is non-NULL, then it points to the |
| 1365 | signal number that should be passed to the LWP when detaching. |
| 1366 | Otherwise pass any pending signal the LWP may have, if any. */ |
| 1367 | |
| 1368 | static void |
| 1369 | detach_one_lwp (struct lwp_info *lp, int *signo_p) |
| 1370 | { |
| 1371 | int lwpid = lp->ptid.lwp (); |
| 1372 | int signo; |
| 1373 | |
| 1374 | gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status)); |
| 1375 | |
| 1376 | if (debug_linux_nat && lp->status) |
| 1377 | fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n", |
| 1378 | strsignal (WSTOPSIG (lp->status)), |
| 1379 | target_pid_to_str (lp->ptid).c_str ()); |
| 1380 | |
| 1381 | /* If there is a pending SIGSTOP, get rid of it. */ |
| 1382 | if (lp->signalled) |
| 1383 | { |
| 1384 | if (debug_linux_nat) |
| 1385 | fprintf_unfiltered (gdb_stdlog, |
| 1386 | "DC: Sending SIGCONT to %s\n", |
| 1387 | target_pid_to_str (lp->ptid).c_str ()); |
| 1388 | |
| 1389 | kill_lwp (lwpid, SIGCONT); |
| 1390 | lp->signalled = 0; |
| 1391 | } |
| 1392 | |
| 1393 | if (signo_p == NULL) |
| 1394 | { |
| 1395 | /* Pass on any pending signal for this LWP. */ |
| 1396 | signo = get_detach_signal (lp); |
| 1397 | } |
| 1398 | else |
| 1399 | signo = *signo_p; |
| 1400 | |
| 1401 | /* Preparing to resume may try to write registers, and fail if the |
| 1402 | lwp is zombie. If that happens, ignore the error. We'll handle |
| 1403 | it below, when detach fails with ESRCH. */ |
| 1404 | try |
| 1405 | { |
| 1406 | linux_target->low_prepare_to_resume (lp); |
| 1407 | } |
| 1408 | catch (const gdb_exception_error &ex) |
| 1409 | { |
| 1410 | if (!check_ptrace_stopped_lwp_gone (lp)) |
| 1411 | throw; |
| 1412 | } |
| 1413 | |
| 1414 | if (ptrace (PTRACE_DETACH, lwpid, 0, signo) < 0) |
| 1415 | { |
| 1416 | int save_errno = errno; |
| 1417 | |
| 1418 | /* We know the thread exists, so ESRCH must mean the lwp is |
| 1419 | zombie. This can happen if one of the already-detached |
| 1420 | threads exits the whole thread group. In that case we're |
| 1421 | still attached, and must reap the lwp. */ |
| 1422 | if (save_errno == ESRCH) |
| 1423 | { |
| 1424 | int ret, status; |
| 1425 | |
| 1426 | ret = my_waitpid (lwpid, &status, __WALL); |
| 1427 | if (ret == -1) |
| 1428 | { |
| 1429 | warning (_("Couldn't reap LWP %d while detaching: %s"), |
| 1430 | lwpid, strerror (errno)); |
| 1431 | } |
| 1432 | else if (!WIFEXITED (status) && !WIFSIGNALED (status)) |
| 1433 | { |
| 1434 | warning (_("Reaping LWP %d while detaching " |
| 1435 | "returned unexpected status 0x%x"), |
| 1436 | lwpid, status); |
| 1437 | } |
| 1438 | } |
| 1439 | else |
| 1440 | { |
| 1441 | error (_("Can't detach %s: %s"), |
| 1442 | target_pid_to_str (lp->ptid).c_str (), |
| 1443 | safe_strerror (save_errno)); |
| 1444 | } |
| 1445 | } |
| 1446 | else if (debug_linux_nat) |
| 1447 | { |
| 1448 | fprintf_unfiltered (gdb_stdlog, |
| 1449 | "PTRACE_DETACH (%s, %s, 0) (OK)\n", |
| 1450 | target_pid_to_str (lp->ptid).c_str (), |
| 1451 | strsignal (signo)); |
| 1452 | } |
| 1453 | |
| 1454 | delete_lwp (lp->ptid); |
| 1455 | } |
| 1456 | |
| 1457 | static int |
| 1458 | detach_callback (struct lwp_info *lp) |
| 1459 | { |
| 1460 | /* We don't actually detach from the thread group leader just yet. |
| 1461 | If the thread group exits, we must reap the zombie clone lwps |
| 1462 | before we're able to reap the leader. */ |
| 1463 | if (lp->ptid.lwp () != lp->ptid.pid ()) |
| 1464 | detach_one_lwp (lp, NULL); |
| 1465 | return 0; |
| 1466 | } |
| 1467 | |
| 1468 | void |
| 1469 | linux_nat_target::detach (inferior *inf, int from_tty) |
| 1470 | { |
| 1471 | struct lwp_info *main_lwp; |
| 1472 | int pid = inf->pid; |
| 1473 | |
| 1474 | /* Don't unregister from the event loop, as there may be other |
| 1475 | inferiors running. */ |
| 1476 | |
| 1477 | /* Stop all threads before detaching. ptrace requires that the |
| 1478 | thread is stopped to sucessfully detach. */ |
| 1479 | iterate_over_lwps (ptid_t (pid), stop_callback); |
| 1480 | /* ... and wait until all of them have reported back that |
| 1481 | they're no longer running. */ |
| 1482 | iterate_over_lwps (ptid_t (pid), stop_wait_callback); |
| 1483 | |
| 1484 | iterate_over_lwps (ptid_t (pid), detach_callback); |
| 1485 | |
| 1486 | /* Only the initial process should be left right now. */ |
| 1487 | gdb_assert (num_lwps (pid) == 1); |
| 1488 | |
| 1489 | main_lwp = find_lwp_pid (ptid_t (pid)); |
| 1490 | |
| 1491 | if (forks_exist_p ()) |
| 1492 | { |
| 1493 | /* Multi-fork case. The current inferior_ptid is being detached |
| 1494 | from, but there are other viable forks to debug. Detach from |
| 1495 | the current fork, and context-switch to the first |
| 1496 | available. */ |
| 1497 | linux_fork_detach (from_tty); |
| 1498 | } |
| 1499 | else |
| 1500 | { |
| 1501 | target_announce_detach (from_tty); |
| 1502 | |
| 1503 | /* Pass on any pending signal for the last LWP. */ |
| 1504 | int signo = get_detach_signal (main_lwp); |
| 1505 | |
| 1506 | detach_one_lwp (main_lwp, &signo); |
| 1507 | |
| 1508 | detach_success (inf); |
| 1509 | } |
| 1510 | } |
| 1511 | |
| 1512 | /* Resume execution of the inferior process. If STEP is nonzero, |
| 1513 | single-step it. If SIGNAL is nonzero, give it that signal. */ |
| 1514 | |
| 1515 | static void |
| 1516 | linux_resume_one_lwp_throw (struct lwp_info *lp, int step, |
| 1517 | enum gdb_signal signo) |
| 1518 | { |
| 1519 | lp->step = step; |
| 1520 | |
| 1521 | /* stop_pc doubles as the PC the LWP had when it was last resumed. |
| 1522 | We only presently need that if the LWP is stepped though (to |
| 1523 | handle the case of stepping a breakpoint instruction). */ |
| 1524 | if (step) |
| 1525 | { |
| 1526 | struct regcache *regcache = get_thread_regcache (lp->ptid); |
| 1527 | |
| 1528 | lp->stop_pc = regcache_read_pc (regcache); |
| 1529 | } |
| 1530 | else |
| 1531 | lp->stop_pc = 0; |
| 1532 | |
| 1533 | linux_target->low_prepare_to_resume (lp); |
| 1534 | linux_target->low_resume (lp->ptid, step, signo); |
| 1535 | |
| 1536 | /* Successfully resumed. Clear state that no longer makes sense, |
| 1537 | and mark the LWP as running. Must not do this before resuming |
| 1538 | otherwise if that fails other code will be confused. E.g., we'd |
| 1539 | later try to stop the LWP and hang forever waiting for a stop |
| 1540 | status. Note that we must not throw after this is cleared, |
| 1541 | otherwise handle_zombie_lwp_error would get confused. */ |
| 1542 | lp->stopped = 0; |
| 1543 | lp->core = -1; |
| 1544 | lp->stop_reason = TARGET_STOPPED_BY_NO_REASON; |
| 1545 | registers_changed_ptid (lp->ptid); |
| 1546 | } |
| 1547 | |
| 1548 | /* Called when we try to resume a stopped LWP and that errors out. If |
| 1549 | the LWP is no longer in ptrace-stopped state (meaning it's zombie, |
| 1550 | or about to become), discard the error, clear any pending status |
| 1551 | the LWP may have, and return true (we'll collect the exit status |
| 1552 | soon enough). Otherwise, return false. */ |
| 1553 | |
| 1554 | static int |
| 1555 | check_ptrace_stopped_lwp_gone (struct lwp_info *lp) |
| 1556 | { |
| 1557 | /* If we get an error after resuming the LWP successfully, we'd |
| 1558 | confuse !T state for the LWP being gone. */ |
| 1559 | gdb_assert (lp->stopped); |
| 1560 | |
| 1561 | /* We can't just check whether the LWP is in 'Z (Zombie)' state, |
| 1562 | because even if ptrace failed with ESRCH, the tracee may be "not |
| 1563 | yet fully dead", but already refusing ptrace requests. In that |
| 1564 | case the tracee has 'R (Running)' state for a little bit |
| 1565 | (observed in Linux 3.18). See also the note on ESRCH in the |
| 1566 | ptrace(2) man page. Instead, check whether the LWP has any state |
| 1567 | other than ptrace-stopped. */ |
| 1568 | |
| 1569 | /* Don't assume anything if /proc/PID/status can't be read. */ |
| 1570 | if (linux_proc_pid_is_trace_stopped_nowarn (lp->ptid.lwp ()) == 0) |
| 1571 | { |
| 1572 | lp->stop_reason = TARGET_STOPPED_BY_NO_REASON; |
| 1573 | lp->status = 0; |
| 1574 | lp->waitstatus.kind = TARGET_WAITKIND_IGNORE; |
| 1575 | return 1; |
| 1576 | } |
| 1577 | return 0; |
| 1578 | } |
| 1579 | |
| 1580 | /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP |
| 1581 | disappears while we try to resume it. */ |
| 1582 | |
| 1583 | static void |
| 1584 | linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo) |
| 1585 | { |
| 1586 | try |
| 1587 | { |
| 1588 | linux_resume_one_lwp_throw (lp, step, signo); |
| 1589 | } |
| 1590 | catch (const gdb_exception_error &ex) |
| 1591 | { |
| 1592 | if (!check_ptrace_stopped_lwp_gone (lp)) |
| 1593 | throw; |
| 1594 | } |
| 1595 | } |
| 1596 | |
| 1597 | /* Resume LP. */ |
| 1598 | |
| 1599 | static void |
| 1600 | resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo) |
| 1601 | { |
| 1602 | if (lp->stopped) |
| 1603 | { |
| 1604 | struct inferior *inf = find_inferior_ptid (lp->ptid); |
| 1605 | |
| 1606 | if (inf->vfork_child != NULL) |
| 1607 | { |
| 1608 | if (debug_linux_nat) |
| 1609 | fprintf_unfiltered (gdb_stdlog, |
| 1610 | "RC: Not resuming %s (vfork parent)\n", |
| 1611 | target_pid_to_str (lp->ptid).c_str ()); |
| 1612 | } |
| 1613 | else if (!lwp_status_pending_p (lp)) |
| 1614 | { |
| 1615 | if (debug_linux_nat) |
| 1616 | fprintf_unfiltered (gdb_stdlog, |
| 1617 | "RC: Resuming sibling %s, %s, %s\n", |
| 1618 | target_pid_to_str (lp->ptid).c_str (), |
| 1619 | (signo != GDB_SIGNAL_0 |
| 1620 | ? strsignal (gdb_signal_to_host (signo)) |
| 1621 | : "0"), |
| 1622 | step ? "step" : "resume"); |
| 1623 | |
| 1624 | linux_resume_one_lwp (lp, step, signo); |
| 1625 | } |
| 1626 | else |
| 1627 | { |
| 1628 | if (debug_linux_nat) |
| 1629 | fprintf_unfiltered (gdb_stdlog, |
| 1630 | "RC: Not resuming sibling %s (has pending)\n", |
| 1631 | target_pid_to_str (lp->ptid).c_str ()); |
| 1632 | } |
| 1633 | } |
| 1634 | else |
| 1635 | { |
| 1636 | if (debug_linux_nat) |
| 1637 | fprintf_unfiltered (gdb_stdlog, |
| 1638 | "RC: Not resuming sibling %s (not stopped)\n", |
| 1639 | target_pid_to_str (lp->ptid).c_str ()); |
| 1640 | } |
| 1641 | } |
| 1642 | |
| 1643 | /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing. |
| 1644 | Resume LWP with the last stop signal, if it is in pass state. */ |
| 1645 | |
| 1646 | static int |
| 1647 | linux_nat_resume_callback (struct lwp_info *lp, struct lwp_info *except) |
| 1648 | { |
| 1649 | enum gdb_signal signo = GDB_SIGNAL_0; |
| 1650 | |
| 1651 | if (lp == except) |
| 1652 | return 0; |
| 1653 | |
| 1654 | if (lp->stopped) |
| 1655 | { |
| 1656 | struct thread_info *thread; |
| 1657 | |
| 1658 | thread = find_thread_ptid (lp->ptid); |
| 1659 | if (thread != NULL) |
| 1660 | { |
| 1661 | signo = thread->suspend.stop_signal; |
| 1662 | thread->suspend.stop_signal = GDB_SIGNAL_0; |
| 1663 | } |
| 1664 | } |
| 1665 | |
| 1666 | resume_lwp (lp, 0, signo); |
| 1667 | return 0; |
| 1668 | } |
| 1669 | |
| 1670 | static int |
| 1671 | resume_clear_callback (struct lwp_info *lp) |
| 1672 | { |
| 1673 | lp->resumed = 0; |
| 1674 | lp->last_resume_kind = resume_stop; |
| 1675 | return 0; |
| 1676 | } |
| 1677 | |
| 1678 | static int |
| 1679 | resume_set_callback (struct lwp_info *lp) |
| 1680 | { |
| 1681 | lp->resumed = 1; |
| 1682 | lp->last_resume_kind = resume_continue; |
| 1683 | return 0; |
| 1684 | } |
| 1685 | |
| 1686 | void |
| 1687 | linux_nat_target::resume (ptid_t ptid, int step, enum gdb_signal signo) |
| 1688 | { |
| 1689 | struct lwp_info *lp; |
| 1690 | int resume_many; |
| 1691 | |
| 1692 | if (debug_linux_nat) |
| 1693 | fprintf_unfiltered (gdb_stdlog, |
| 1694 | "LLR: Preparing to %s %s, %s, inferior_ptid %s\n", |
| 1695 | step ? "step" : "resume", |
| 1696 | target_pid_to_str (ptid).c_str (), |
| 1697 | (signo != GDB_SIGNAL_0 |
| 1698 | ? strsignal (gdb_signal_to_host (signo)) : "0"), |
| 1699 | target_pid_to_str (inferior_ptid).c_str ()); |
| 1700 | |
| 1701 | /* A specific PTID means `step only this process id'. */ |
| 1702 | resume_many = (minus_one_ptid == ptid |
| 1703 | || ptid.is_pid ()); |
| 1704 | |
| 1705 | /* Mark the lwps we're resuming as resumed. */ |
| 1706 | iterate_over_lwps (ptid, resume_set_callback); |
| 1707 | |
| 1708 | /* See if it's the current inferior that should be handled |
| 1709 | specially. */ |
| 1710 | if (resume_many) |
| 1711 | lp = find_lwp_pid (inferior_ptid); |
| 1712 | else |
| 1713 | lp = find_lwp_pid (ptid); |
| 1714 | gdb_assert (lp != NULL); |
| 1715 | |
| 1716 | /* Remember if we're stepping. */ |
| 1717 | lp->last_resume_kind = step ? resume_step : resume_continue; |
| 1718 | |
| 1719 | /* If we have a pending wait status for this thread, there is no |
| 1720 | point in resuming the process. But first make sure that |
| 1721 | linux_nat_wait won't preemptively handle the event - we |
| 1722 | should never take this short-circuit if we are going to |
| 1723 | leave LP running, since we have skipped resuming all the |
| 1724 | other threads. This bit of code needs to be synchronized |
| 1725 | with linux_nat_wait. */ |
| 1726 | |
| 1727 | if (lp->status && WIFSTOPPED (lp->status)) |
| 1728 | { |
| 1729 | if (!lp->step |
| 1730 | && WSTOPSIG (lp->status) |
| 1731 | && sigismember (&pass_mask, WSTOPSIG (lp->status))) |
| 1732 | { |
| 1733 | if (debug_linux_nat) |
| 1734 | fprintf_unfiltered (gdb_stdlog, |
| 1735 | "LLR: Not short circuiting for ignored " |
| 1736 | "status 0x%x\n", lp->status); |
| 1737 | |
| 1738 | /* FIXME: What should we do if we are supposed to continue |
| 1739 | this thread with a signal? */ |
| 1740 | gdb_assert (signo == GDB_SIGNAL_0); |
| 1741 | signo = gdb_signal_from_host (WSTOPSIG (lp->status)); |
| 1742 | lp->status = 0; |
| 1743 | } |
| 1744 | } |
| 1745 | |
| 1746 | if (lwp_status_pending_p (lp)) |
| 1747 | { |
| 1748 | /* FIXME: What should we do if we are supposed to continue |
| 1749 | this thread with a signal? */ |
| 1750 | gdb_assert (signo == GDB_SIGNAL_0); |
| 1751 | |
| 1752 | if (debug_linux_nat) |
| 1753 | fprintf_unfiltered (gdb_stdlog, |
| 1754 | "LLR: Short circuiting for status 0x%x\n", |
| 1755 | lp->status); |
| 1756 | |
| 1757 | if (target_can_async_p ()) |
| 1758 | { |
| 1759 | target_async (1); |
| 1760 | /* Tell the event loop we have something to process. */ |
| 1761 | async_file_mark (); |
| 1762 | } |
| 1763 | return; |
| 1764 | } |
| 1765 | |
| 1766 | if (resume_many) |
| 1767 | iterate_over_lwps (ptid, [=] (struct lwp_info *info) |
| 1768 | { |
| 1769 | return linux_nat_resume_callback (info, lp); |
| 1770 | }); |
| 1771 | |
| 1772 | if (debug_linux_nat) |
| 1773 | fprintf_unfiltered (gdb_stdlog, |
| 1774 | "LLR: %s %s, %s (resume event thread)\n", |
| 1775 | step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT", |
| 1776 | target_pid_to_str (lp->ptid).c_str (), |
| 1777 | (signo != GDB_SIGNAL_0 |
| 1778 | ? strsignal (gdb_signal_to_host (signo)) : "0")); |
| 1779 | |
| 1780 | linux_resume_one_lwp (lp, step, signo); |
| 1781 | |
| 1782 | if (target_can_async_p ()) |
| 1783 | target_async (1); |
| 1784 | } |
| 1785 | |
| 1786 | /* Send a signal to an LWP. */ |
| 1787 | |
| 1788 | static int |
| 1789 | kill_lwp (int lwpid, int signo) |
| 1790 | { |
| 1791 | int ret; |
| 1792 | |
| 1793 | errno = 0; |
| 1794 | ret = syscall (__NR_tkill, lwpid, signo); |
| 1795 | if (errno == ENOSYS) |
| 1796 | { |
| 1797 | /* If tkill fails, then we are not using nptl threads, a |
| 1798 | configuration we no longer support. */ |
| 1799 | perror_with_name (("tkill")); |
| 1800 | } |
| 1801 | return ret; |
| 1802 | } |
| 1803 | |
| 1804 | /* Handle a GNU/Linux syscall trap wait response. If we see a syscall |
| 1805 | event, check if the core is interested in it: if not, ignore the |
| 1806 | event, and keep waiting; otherwise, we need to toggle the LWP's |
| 1807 | syscall entry/exit status, since the ptrace event itself doesn't |
| 1808 | indicate it, and report the trap to higher layers. */ |
| 1809 | |
| 1810 | static int |
| 1811 | linux_handle_syscall_trap (struct lwp_info *lp, int stopping) |
| 1812 | { |
| 1813 | struct target_waitstatus *ourstatus = &lp->waitstatus; |
| 1814 | struct gdbarch *gdbarch = target_thread_architecture (lp->ptid); |
| 1815 | thread_info *thread = find_thread_ptid (lp->ptid); |
| 1816 | int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, thread); |
| 1817 | |
| 1818 | if (stopping) |
| 1819 | { |
| 1820 | /* If we're stopping threads, there's a SIGSTOP pending, which |
| 1821 | makes it so that the LWP reports an immediate syscall return, |
| 1822 | followed by the SIGSTOP. Skip seeing that "return" using |
| 1823 | PTRACE_CONT directly, and let stop_wait_callback collect the |
| 1824 | SIGSTOP. Later when the thread is resumed, a new syscall |
| 1825 | entry event. If we didn't do this (and returned 0), we'd |
| 1826 | leave a syscall entry pending, and our caller, by using |
| 1827 | PTRACE_CONT to collect the SIGSTOP, skips the syscall return |
| 1828 | itself. Later, when the user re-resumes this LWP, we'd see |
| 1829 | another syscall entry event and we'd mistake it for a return. |
| 1830 | |
| 1831 | If stop_wait_callback didn't force the SIGSTOP out of the LWP |
| 1832 | (leaving immediately with LWP->signalled set, without issuing |
| 1833 | a PTRACE_CONT), it would still be problematic to leave this |
| 1834 | syscall enter pending, as later when the thread is resumed, |
| 1835 | it would then see the same syscall exit mentioned above, |
| 1836 | followed by the delayed SIGSTOP, while the syscall didn't |
| 1837 | actually get to execute. It seems it would be even more |
| 1838 | confusing to the user. */ |
| 1839 | |
| 1840 | if (debug_linux_nat) |
| 1841 | fprintf_unfiltered (gdb_stdlog, |
| 1842 | "LHST: ignoring syscall %d " |
| 1843 | "for LWP %ld (stopping threads), " |
| 1844 | "resuming with PTRACE_CONT for SIGSTOP\n", |
| 1845 | syscall_number, |
| 1846 | lp->ptid.lwp ()); |
| 1847 | |
| 1848 | lp->syscall_state = TARGET_WAITKIND_IGNORE; |
| 1849 | ptrace (PTRACE_CONT, lp->ptid.lwp (), 0, 0); |
| 1850 | lp->stopped = 0; |
| 1851 | return 1; |
| 1852 | } |
| 1853 | |
| 1854 | /* Always update the entry/return state, even if this particular |
| 1855 | syscall isn't interesting to the core now. In async mode, |
| 1856 | the user could install a new catchpoint for this syscall |
| 1857 | between syscall enter/return, and we'll need to know to |
| 1858 | report a syscall return if that happens. */ |
| 1859 | lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY |
| 1860 | ? TARGET_WAITKIND_SYSCALL_RETURN |
| 1861 | : TARGET_WAITKIND_SYSCALL_ENTRY); |
| 1862 | |
| 1863 | if (catch_syscall_enabled ()) |
| 1864 | { |
| 1865 | if (catching_syscall_number (syscall_number)) |
| 1866 | { |
| 1867 | /* Alright, an event to report. */ |
| 1868 | ourstatus->kind = lp->syscall_state; |
| 1869 | ourstatus->value.syscall_number = syscall_number; |
| 1870 | |
| 1871 | if (debug_linux_nat) |
| 1872 | fprintf_unfiltered (gdb_stdlog, |
| 1873 | "LHST: stopping for %s of syscall %d" |
| 1874 | " for LWP %ld\n", |
| 1875 | lp->syscall_state |
| 1876 | == TARGET_WAITKIND_SYSCALL_ENTRY |
| 1877 | ? "entry" : "return", |
| 1878 | syscall_number, |
| 1879 | lp->ptid.lwp ()); |
| 1880 | return 0; |
| 1881 | } |
| 1882 | |
| 1883 | if (debug_linux_nat) |
| 1884 | fprintf_unfiltered (gdb_stdlog, |
| 1885 | "LHST: ignoring %s of syscall %d " |
| 1886 | "for LWP %ld\n", |
| 1887 | lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY |
| 1888 | ? "entry" : "return", |
| 1889 | syscall_number, |
| 1890 | lp->ptid.lwp ()); |
| 1891 | } |
| 1892 | else |
| 1893 | { |
| 1894 | /* If we had been syscall tracing, and hence used PT_SYSCALL |
| 1895 | before on this LWP, it could happen that the user removes all |
| 1896 | syscall catchpoints before we get to process this event. |
| 1897 | There are two noteworthy issues here: |
| 1898 | |
| 1899 | - When stopped at a syscall entry event, resuming with |
| 1900 | PT_STEP still resumes executing the syscall and reports a |
| 1901 | syscall return. |
| 1902 | |
| 1903 | - Only PT_SYSCALL catches syscall enters. If we last |
| 1904 | single-stepped this thread, then this event can't be a |
| 1905 | syscall enter. If we last single-stepped this thread, this |
| 1906 | has to be a syscall exit. |
| 1907 | |
| 1908 | The points above mean that the next resume, be it PT_STEP or |
| 1909 | PT_CONTINUE, can not trigger a syscall trace event. */ |
| 1910 | if (debug_linux_nat) |
| 1911 | fprintf_unfiltered (gdb_stdlog, |
| 1912 | "LHST: caught syscall event " |
| 1913 | "with no syscall catchpoints." |
| 1914 | " %d for LWP %ld, ignoring\n", |
| 1915 | syscall_number, |
| 1916 | lp->ptid.lwp ()); |
| 1917 | lp->syscall_state = TARGET_WAITKIND_IGNORE; |
| 1918 | } |
| 1919 | |
| 1920 | /* The core isn't interested in this event. For efficiency, avoid |
| 1921 | stopping all threads only to have the core resume them all again. |
| 1922 | Since we're not stopping threads, if we're still syscall tracing |
| 1923 | and not stepping, we can't use PTRACE_CONT here, as we'd miss any |
| 1924 | subsequent syscall. Simply resume using the inf-ptrace layer, |
| 1925 | which knows when to use PT_SYSCALL or PT_CONTINUE. */ |
| 1926 | |
| 1927 | linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0); |
| 1928 | return 1; |
| 1929 | } |
| 1930 | |
| 1931 | /* Handle a GNU/Linux extended wait response. If we see a clone |
| 1932 | event, we need to add the new LWP to our list (and not report the |
| 1933 | trap to higher layers). This function returns non-zero if the |
| 1934 | event should be ignored and we should wait again. If STOPPING is |
| 1935 | true, the new LWP remains stopped, otherwise it is continued. */ |
| 1936 | |
| 1937 | static int |
| 1938 | linux_handle_extended_wait (struct lwp_info *lp, int status) |
| 1939 | { |
| 1940 | int pid = lp->ptid.lwp (); |
| 1941 | struct target_waitstatus *ourstatus = &lp->waitstatus; |
| 1942 | int event = linux_ptrace_get_extended_event (status); |
| 1943 | |
| 1944 | /* All extended events we currently use are mid-syscall. Only |
| 1945 | PTRACE_EVENT_STOP is delivered more like a signal-stop, but |
| 1946 | you have to be using PTRACE_SEIZE to get that. */ |
| 1947 | lp->syscall_state = TARGET_WAITKIND_SYSCALL_ENTRY; |
| 1948 | |
| 1949 | if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK |
| 1950 | || event == PTRACE_EVENT_CLONE) |
| 1951 | { |
| 1952 | unsigned long new_pid; |
| 1953 | int ret; |
| 1954 | |
| 1955 | ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid); |
| 1956 | |
| 1957 | /* If we haven't already seen the new PID stop, wait for it now. */ |
| 1958 | if (! pull_pid_from_list (&stopped_pids, new_pid, &status)) |
| 1959 | { |
| 1960 | /* The new child has a pending SIGSTOP. We can't affect it until it |
| 1961 | hits the SIGSTOP, but we're already attached. */ |
| 1962 | ret = my_waitpid (new_pid, &status, __WALL); |
| 1963 | if (ret == -1) |
| 1964 | perror_with_name (_("waiting for new child")); |
| 1965 | else if (ret != new_pid) |
| 1966 | internal_error (__FILE__, __LINE__, |
| 1967 | _("wait returned unexpected PID %d"), ret); |
| 1968 | else if (!WIFSTOPPED (status)) |
| 1969 | internal_error (__FILE__, __LINE__, |
| 1970 | _("wait returned unexpected status 0x%x"), status); |
| 1971 | } |
| 1972 | |
| 1973 | ourstatus->value.related_pid = ptid_t (new_pid, new_pid, 0); |
| 1974 | |
| 1975 | if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK) |
| 1976 | { |
| 1977 | /* The arch-specific native code may need to know about new |
| 1978 | forks even if those end up never mapped to an |
| 1979 | inferior. */ |
| 1980 | linux_target->low_new_fork (lp, new_pid); |
| 1981 | } |
| 1982 | |
| 1983 | if (event == PTRACE_EVENT_FORK |
| 1984 | && linux_fork_checkpointing_p (lp->ptid.pid ())) |
| 1985 | { |
| 1986 | /* Handle checkpointing by linux-fork.c here as a special |
| 1987 | case. We don't want the follow-fork-mode or 'catch fork' |
| 1988 | to interfere with this. */ |
| 1989 | |
| 1990 | /* This won't actually modify the breakpoint list, but will |
| 1991 | physically remove the breakpoints from the child. */ |
| 1992 | detach_breakpoints (ptid_t (new_pid, new_pid, 0)); |
| 1993 | |
| 1994 | /* Retain child fork in ptrace (stopped) state. */ |
| 1995 | if (!find_fork_pid (new_pid)) |
| 1996 | add_fork (new_pid); |
| 1997 | |
| 1998 | /* Report as spurious, so that infrun doesn't want to follow |
| 1999 | this fork. We're actually doing an infcall in |
| 2000 | linux-fork.c. */ |
| 2001 | ourstatus->kind = TARGET_WAITKIND_SPURIOUS; |
| 2002 | |
| 2003 | /* Report the stop to the core. */ |
| 2004 | return 0; |
| 2005 | } |
| 2006 | |
| 2007 | if (event == PTRACE_EVENT_FORK) |
| 2008 | ourstatus->kind = TARGET_WAITKIND_FORKED; |
| 2009 | else if (event == PTRACE_EVENT_VFORK) |
| 2010 | ourstatus->kind = TARGET_WAITKIND_VFORKED; |
| 2011 | else if (event == PTRACE_EVENT_CLONE) |
| 2012 | { |
| 2013 | struct lwp_info *new_lp; |
| 2014 | |
| 2015 | ourstatus->kind = TARGET_WAITKIND_IGNORE; |
| 2016 | |
| 2017 | if (debug_linux_nat) |
| 2018 | fprintf_unfiltered (gdb_stdlog, |
| 2019 | "LHEW: Got clone event " |
| 2020 | "from LWP %d, new child is LWP %ld\n", |
| 2021 | pid, new_pid); |
| 2022 | |
| 2023 | new_lp = add_lwp (ptid_t (lp->ptid.pid (), new_pid, 0)); |
| 2024 | new_lp->stopped = 1; |
| 2025 | new_lp->resumed = 1; |
| 2026 | |
| 2027 | /* If the thread_db layer is active, let it record the user |
| 2028 | level thread id and status, and add the thread to GDB's |
| 2029 | list. */ |
| 2030 | if (!thread_db_notice_clone (lp->ptid, new_lp->ptid)) |
| 2031 | { |
| 2032 | /* The process is not using thread_db. Add the LWP to |
| 2033 | GDB's list. */ |
| 2034 | target_post_attach (new_lp->ptid.lwp ()); |
| 2035 | add_thread (new_lp->ptid); |
| 2036 | } |
| 2037 | |
| 2038 | /* Even if we're stopping the thread for some reason |
| 2039 | internal to this module, from the perspective of infrun |
| 2040 | and the user/frontend, this new thread is running until |
| 2041 | it next reports a stop. */ |
| 2042 | set_running (new_lp->ptid, 1); |
| 2043 | set_executing (new_lp->ptid, 1); |
| 2044 | |
| 2045 | if (WSTOPSIG (status) != SIGSTOP) |
| 2046 | { |
| 2047 | /* This can happen if someone starts sending signals to |
| 2048 | the new thread before it gets a chance to run, which |
| 2049 | have a lower number than SIGSTOP (e.g. SIGUSR1). |
| 2050 | This is an unlikely case, and harder to handle for |
| 2051 | fork / vfork than for clone, so we do not try - but |
| 2052 | we handle it for clone events here. */ |
| 2053 | |
| 2054 | new_lp->signalled = 1; |
| 2055 | |
| 2056 | /* We created NEW_LP so it cannot yet contain STATUS. */ |
| 2057 | gdb_assert (new_lp->status == 0); |
| 2058 | |
| 2059 | /* Save the wait status to report later. */ |
| 2060 | if (debug_linux_nat) |
| 2061 | fprintf_unfiltered (gdb_stdlog, |
| 2062 | "LHEW: waitpid of new LWP %ld, " |
| 2063 | "saving status %s\n", |
| 2064 | (long) new_lp->ptid.lwp (), |
| 2065 | status_to_str (status)); |
| 2066 | new_lp->status = status; |
| 2067 | } |
| 2068 | else if (report_thread_events) |
| 2069 | { |
| 2070 | new_lp->waitstatus.kind = TARGET_WAITKIND_THREAD_CREATED; |
| 2071 | new_lp->status = status; |
| 2072 | } |
| 2073 | |
| 2074 | return 1; |
| 2075 | } |
| 2076 | |
| 2077 | return 0; |
| 2078 | } |
| 2079 | |
| 2080 | if (event == PTRACE_EVENT_EXEC) |
| 2081 | { |
| 2082 | if (debug_linux_nat) |
| 2083 | fprintf_unfiltered (gdb_stdlog, |
| 2084 | "LHEW: Got exec event from LWP %ld\n", |
| 2085 | lp->ptid.lwp ()); |
| 2086 | |
| 2087 | ourstatus->kind = TARGET_WAITKIND_EXECD; |
| 2088 | ourstatus->value.execd_pathname |
| 2089 | = xstrdup (linux_proc_pid_to_exec_file (pid)); |
| 2090 | |
| 2091 | /* The thread that execed must have been resumed, but, when a |
| 2092 | thread execs, it changes its tid to the tgid, and the old |
| 2093 | tgid thread might have not been resumed. */ |
| 2094 | lp->resumed = 1; |
| 2095 | return 0; |
| 2096 | } |
| 2097 | |
| 2098 | if (event == PTRACE_EVENT_VFORK_DONE) |
| 2099 | { |
| 2100 | if (current_inferior ()->waiting_for_vfork_done) |
| 2101 | { |
| 2102 | if (debug_linux_nat) |
| 2103 | fprintf_unfiltered (gdb_stdlog, |
| 2104 | "LHEW: Got expected PTRACE_EVENT_" |
| 2105 | "VFORK_DONE from LWP %ld: stopping\n", |
| 2106 | lp->ptid.lwp ()); |
| 2107 | |
| 2108 | ourstatus->kind = TARGET_WAITKIND_VFORK_DONE; |
| 2109 | return 0; |
| 2110 | } |
| 2111 | |
| 2112 | if (debug_linux_nat) |
| 2113 | fprintf_unfiltered (gdb_stdlog, |
| 2114 | "LHEW: Got PTRACE_EVENT_VFORK_DONE " |
| 2115 | "from LWP %ld: ignoring\n", |
| 2116 | lp->ptid.lwp ()); |
| 2117 | return 1; |
| 2118 | } |
| 2119 | |
| 2120 | internal_error (__FILE__, __LINE__, |
| 2121 | _("unknown ptrace event %d"), event); |
| 2122 | } |
| 2123 | |
| 2124 | /* Suspend waiting for a signal. We're mostly interested in |
| 2125 | SIGCHLD/SIGINT. */ |
| 2126 | |
| 2127 | static void |
| 2128 | wait_for_signal () |
| 2129 | { |
| 2130 | if (debug_linux_nat) |
| 2131 | fprintf_unfiltered (gdb_stdlog, "linux-nat: about to sigsuspend\n"); |
| 2132 | sigsuspend (&suspend_mask); |
| 2133 | |
| 2134 | /* If the quit flag is set, it means that the user pressed Ctrl-C |
| 2135 | and we're debugging a process that is running on a separate |
| 2136 | terminal, so we must forward the Ctrl-C to the inferior. (If the |
| 2137 | inferior is sharing GDB's terminal, then the Ctrl-C reaches the |
| 2138 | inferior directly.) We must do this here because functions that |
| 2139 | need to block waiting for a signal loop forever until there's an |
| 2140 | event to report before returning back to the event loop. */ |
| 2141 | if (!target_terminal::is_ours ()) |
| 2142 | { |
| 2143 | if (check_quit_flag ()) |
| 2144 | target_pass_ctrlc (); |
| 2145 | } |
| 2146 | } |
| 2147 | |
| 2148 | /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has |
| 2149 | exited. */ |
| 2150 | |
| 2151 | static int |
| 2152 | wait_lwp (struct lwp_info *lp) |
| 2153 | { |
| 2154 | pid_t pid; |
| 2155 | int status = 0; |
| 2156 | int thread_dead = 0; |
| 2157 | sigset_t prev_mask; |
| 2158 | |
| 2159 | gdb_assert (!lp->stopped); |
| 2160 | gdb_assert (lp->status == 0); |
| 2161 | |
| 2162 | /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */ |
| 2163 | block_child_signals (&prev_mask); |
| 2164 | |
| 2165 | for (;;) |
| 2166 | { |
| 2167 | pid = my_waitpid (lp->ptid.lwp (), &status, __WALL | WNOHANG); |
| 2168 | if (pid == -1 && errno == ECHILD) |
| 2169 | { |
| 2170 | /* The thread has previously exited. We need to delete it |
| 2171 | now because if this was a non-leader thread execing, we |
| 2172 | won't get an exit event. See comments on exec events at |
| 2173 | the top of the file. */ |
| 2174 | thread_dead = 1; |
| 2175 | if (debug_linux_nat) |
| 2176 | fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n", |
| 2177 | target_pid_to_str (lp->ptid).c_str ()); |
| 2178 | } |
| 2179 | if (pid != 0) |
| 2180 | break; |
| 2181 | |
| 2182 | /* Bugs 10970, 12702. |
| 2183 | Thread group leader may have exited in which case we'll lock up in |
| 2184 | waitpid if there are other threads, even if they are all zombies too. |
| 2185 | Basically, we're not supposed to use waitpid this way. |
| 2186 | tkill(pid,0) cannot be used here as it gets ESRCH for both |
| 2187 | for zombie and running processes. |
| 2188 | |
| 2189 | As a workaround, check if we're waiting for the thread group leader and |
| 2190 | if it's a zombie, and avoid calling waitpid if it is. |
| 2191 | |
| 2192 | This is racy, what if the tgl becomes a zombie right after we check? |
| 2193 | Therefore always use WNOHANG with sigsuspend - it is equivalent to |
| 2194 | waiting waitpid but linux_proc_pid_is_zombie is safe this way. */ |
| 2195 | |
| 2196 | if (lp->ptid.pid () == lp->ptid.lwp () |
| 2197 | && linux_proc_pid_is_zombie (lp->ptid.lwp ())) |
| 2198 | { |
| 2199 | thread_dead = 1; |
| 2200 | if (debug_linux_nat) |
| 2201 | fprintf_unfiltered (gdb_stdlog, |
| 2202 | "WL: Thread group leader %s vanished.\n", |
| 2203 | target_pid_to_str (lp->ptid).c_str ()); |
| 2204 | break; |
| 2205 | } |
| 2206 | |
| 2207 | /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers |
| 2208 | get invoked despite our caller had them intentionally blocked by |
| 2209 | block_child_signals. This is sensitive only to the loop of |
| 2210 | linux_nat_wait_1 and there if we get called my_waitpid gets called |
| 2211 | again before it gets to sigsuspend so we can safely let the handlers |
| 2212 | get executed here. */ |
| 2213 | wait_for_signal (); |
| 2214 | } |
| 2215 | |
| 2216 | restore_child_signals_mask (&prev_mask); |
| 2217 | |
| 2218 | if (!thread_dead) |
| 2219 | { |
| 2220 | gdb_assert (pid == lp->ptid.lwp ()); |
| 2221 | |
| 2222 | if (debug_linux_nat) |
| 2223 | { |
| 2224 | fprintf_unfiltered (gdb_stdlog, |
| 2225 | "WL: waitpid %s received %s\n", |
| 2226 | target_pid_to_str (lp->ptid).c_str (), |
| 2227 | status_to_str (status)); |
| 2228 | } |
| 2229 | |
| 2230 | /* Check if the thread has exited. */ |
| 2231 | if (WIFEXITED (status) || WIFSIGNALED (status)) |
| 2232 | { |
| 2233 | if (report_thread_events |
| 2234 | || lp->ptid.pid () == lp->ptid.lwp ()) |
| 2235 | { |
| 2236 | if (debug_linux_nat) |
| 2237 | fprintf_unfiltered (gdb_stdlog, "WL: LWP %d exited.\n", |
| 2238 | lp->ptid.pid ()); |
| 2239 | |
| 2240 | /* If this is the leader exiting, it means the whole |
| 2241 | process is gone. Store the status to report to the |
| 2242 | core. Store it in lp->waitstatus, because lp->status |
| 2243 | would be ambiguous (W_EXITCODE(0,0) == 0). */ |
| 2244 | store_waitstatus (&lp->waitstatus, status); |
| 2245 | return 0; |
| 2246 | } |
| 2247 | |
| 2248 | thread_dead = 1; |
| 2249 | if (debug_linux_nat) |
| 2250 | fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n", |
| 2251 | target_pid_to_str (lp->ptid).c_str ()); |
| 2252 | } |
| 2253 | } |
| 2254 | |
| 2255 | if (thread_dead) |
| 2256 | { |
| 2257 | exit_lwp (lp); |
| 2258 | return 0; |
| 2259 | } |
| 2260 | |
| 2261 | gdb_assert (WIFSTOPPED (status)); |
| 2262 | lp->stopped = 1; |
| 2263 | |
| 2264 | if (lp->must_set_ptrace_flags) |
| 2265 | { |
| 2266 | struct inferior *inf = find_inferior_pid (lp->ptid.pid ()); |
| 2267 | int options = linux_nat_ptrace_options (inf->attach_flag); |
| 2268 | |
| 2269 | linux_enable_event_reporting (lp->ptid.lwp (), options); |
| 2270 | lp->must_set_ptrace_flags = 0; |
| 2271 | } |
| 2272 | |
| 2273 | /* Handle GNU/Linux's syscall SIGTRAPs. */ |
| 2274 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP) |
| 2275 | { |
| 2276 | /* No longer need the sysgood bit. The ptrace event ends up |
| 2277 | recorded in lp->waitstatus if we care for it. We can carry |
| 2278 | on handling the event like a regular SIGTRAP from here |
| 2279 | on. */ |
| 2280 | status = W_STOPCODE (SIGTRAP); |
| 2281 | if (linux_handle_syscall_trap (lp, 1)) |
| 2282 | return wait_lwp (lp); |
| 2283 | } |
| 2284 | else |
| 2285 | { |
| 2286 | /* Almost all other ptrace-stops are known to be outside of system |
| 2287 | calls, with further exceptions in linux_handle_extended_wait. */ |
| 2288 | lp->syscall_state = TARGET_WAITKIND_IGNORE; |
| 2289 | } |
| 2290 | |
| 2291 | /* Handle GNU/Linux's extended waitstatus for trace events. */ |
| 2292 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP |
| 2293 | && linux_is_extended_waitstatus (status)) |
| 2294 | { |
| 2295 | if (debug_linux_nat) |
| 2296 | fprintf_unfiltered (gdb_stdlog, |
| 2297 | "WL: Handling extended status 0x%06x\n", |
| 2298 | status); |
| 2299 | linux_handle_extended_wait (lp, status); |
| 2300 | return 0; |
| 2301 | } |
| 2302 | |
| 2303 | return status; |
| 2304 | } |
| 2305 | |
| 2306 | /* Send a SIGSTOP to LP. */ |
| 2307 | |
| 2308 | static int |
| 2309 | stop_callback (struct lwp_info *lp) |
| 2310 | { |
| 2311 | if (!lp->stopped && !lp->signalled) |
| 2312 | { |
| 2313 | int ret; |
| 2314 | |
| 2315 | if (debug_linux_nat) |
| 2316 | { |
| 2317 | fprintf_unfiltered (gdb_stdlog, |
| 2318 | "SC: kill %s **<SIGSTOP>**\n", |
| 2319 | target_pid_to_str (lp->ptid).c_str ()); |
| 2320 | } |
| 2321 | errno = 0; |
| 2322 | ret = kill_lwp (lp->ptid.lwp (), SIGSTOP); |
| 2323 | if (debug_linux_nat) |
| 2324 | { |
| 2325 | fprintf_unfiltered (gdb_stdlog, |
| 2326 | "SC: lwp kill %d %s\n", |
| 2327 | ret, |
| 2328 | errno ? safe_strerror (errno) : "ERRNO-OK"); |
| 2329 | } |
| 2330 | |
| 2331 | lp->signalled = 1; |
| 2332 | gdb_assert (lp->status == 0); |
| 2333 | } |
| 2334 | |
| 2335 | return 0; |
| 2336 | } |
| 2337 | |
| 2338 | /* Request a stop on LWP. */ |
| 2339 | |
| 2340 | void |
| 2341 | linux_stop_lwp (struct lwp_info *lwp) |
| 2342 | { |
| 2343 | stop_callback (lwp); |
| 2344 | } |
| 2345 | |
| 2346 | /* See linux-nat.h */ |
| 2347 | |
| 2348 | void |
| 2349 | linux_stop_and_wait_all_lwps (void) |
| 2350 | { |
| 2351 | /* Stop all LWP's ... */ |
| 2352 | iterate_over_lwps (minus_one_ptid, stop_callback); |
| 2353 | |
| 2354 | /* ... and wait until all of them have reported back that |
| 2355 | they're no longer running. */ |
| 2356 | iterate_over_lwps (minus_one_ptid, stop_wait_callback); |
| 2357 | } |
| 2358 | |
| 2359 | /* See linux-nat.h */ |
| 2360 | |
| 2361 | void |
| 2362 | linux_unstop_all_lwps (void) |
| 2363 | { |
| 2364 | iterate_over_lwps (minus_one_ptid, |
| 2365 | [] (struct lwp_info *info) |
| 2366 | { |
| 2367 | return resume_stopped_resumed_lwps (info, minus_one_ptid); |
| 2368 | }); |
| 2369 | } |
| 2370 | |
| 2371 | /* Return non-zero if LWP PID has a pending SIGINT. */ |
| 2372 | |
| 2373 | static int |
| 2374 | linux_nat_has_pending_sigint (int pid) |
| 2375 | { |
| 2376 | sigset_t pending, blocked, ignored; |
| 2377 | |
| 2378 | linux_proc_pending_signals (pid, &pending, &blocked, &ignored); |
| 2379 | |
| 2380 | if (sigismember (&pending, SIGINT) |
| 2381 | && !sigismember (&ignored, SIGINT)) |
| 2382 | return 1; |
| 2383 | |
| 2384 | return 0; |
| 2385 | } |
| 2386 | |
| 2387 | /* Set a flag in LP indicating that we should ignore its next SIGINT. */ |
| 2388 | |
| 2389 | static int |
| 2390 | set_ignore_sigint (struct lwp_info *lp) |
| 2391 | { |
| 2392 | /* If a thread has a pending SIGINT, consume it; otherwise, set a |
| 2393 | flag to consume the next one. */ |
| 2394 | if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status) |
| 2395 | && WSTOPSIG (lp->status) == SIGINT) |
| 2396 | lp->status = 0; |
| 2397 | else |
| 2398 | lp->ignore_sigint = 1; |
| 2399 | |
| 2400 | return 0; |
| 2401 | } |
| 2402 | |
| 2403 | /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag. |
| 2404 | This function is called after we know the LWP has stopped; if the LWP |
| 2405 | stopped before the expected SIGINT was delivered, then it will never have |
| 2406 | arrived. Also, if the signal was delivered to a shared queue and consumed |
| 2407 | by a different thread, it will never be delivered to this LWP. */ |
| 2408 | |
| 2409 | static void |
| 2410 | maybe_clear_ignore_sigint (struct lwp_info *lp) |
| 2411 | { |
| 2412 | if (!lp->ignore_sigint) |
| 2413 | return; |
| 2414 | |
| 2415 | if (!linux_nat_has_pending_sigint (lp->ptid.lwp ())) |
| 2416 | { |
| 2417 | if (debug_linux_nat) |
| 2418 | fprintf_unfiltered (gdb_stdlog, |
| 2419 | "MCIS: Clearing bogus flag for %s\n", |
| 2420 | target_pid_to_str (lp->ptid).c_str ()); |
| 2421 | lp->ignore_sigint = 0; |
| 2422 | } |
| 2423 | } |
| 2424 | |
| 2425 | /* Fetch the possible triggered data watchpoint info and store it in |
| 2426 | LP. |
| 2427 | |
| 2428 | On some archs, like x86, that use debug registers to set |
| 2429 | watchpoints, it's possible that the way to know which watched |
| 2430 | address trapped, is to check the register that is used to select |
| 2431 | which address to watch. Problem is, between setting the watchpoint |
| 2432 | and reading back which data address trapped, the user may change |
| 2433 | the set of watchpoints, and, as a consequence, GDB changes the |
| 2434 | debug registers in the inferior. To avoid reading back a stale |
| 2435 | stopped-data-address when that happens, we cache in LP the fact |
| 2436 | that a watchpoint trapped, and the corresponding data address, as |
| 2437 | soon as we see LP stop with a SIGTRAP. If GDB changes the debug |
| 2438 | registers meanwhile, we have the cached data we can rely on. */ |
| 2439 | |
| 2440 | static int |
| 2441 | check_stopped_by_watchpoint (struct lwp_info *lp) |
| 2442 | { |
| 2443 | scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid); |
| 2444 | inferior_ptid = lp->ptid; |
| 2445 | |
| 2446 | if (linux_target->low_stopped_by_watchpoint ()) |
| 2447 | { |
| 2448 | lp->stop_reason = TARGET_STOPPED_BY_WATCHPOINT; |
| 2449 | lp->stopped_data_address_p |
| 2450 | = linux_target->low_stopped_data_address (&lp->stopped_data_address); |
| 2451 | } |
| 2452 | |
| 2453 | return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT; |
| 2454 | } |
| 2455 | |
| 2456 | /* Returns true if the LWP had stopped for a watchpoint. */ |
| 2457 | |
| 2458 | bool |
| 2459 | linux_nat_target::stopped_by_watchpoint () |
| 2460 | { |
| 2461 | struct lwp_info *lp = find_lwp_pid (inferior_ptid); |
| 2462 | |
| 2463 | gdb_assert (lp != NULL); |
| 2464 | |
| 2465 | return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT; |
| 2466 | } |
| 2467 | |
| 2468 | bool |
| 2469 | linux_nat_target::stopped_data_address (CORE_ADDR *addr_p) |
| 2470 | { |
| 2471 | struct lwp_info *lp = find_lwp_pid (inferior_ptid); |
| 2472 | |
| 2473 | gdb_assert (lp != NULL); |
| 2474 | |
| 2475 | *addr_p = lp->stopped_data_address; |
| 2476 | |
| 2477 | return lp->stopped_data_address_p; |
| 2478 | } |
| 2479 | |
| 2480 | /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */ |
| 2481 | |
| 2482 | bool |
| 2483 | linux_nat_target::low_status_is_event (int status) |
| 2484 | { |
| 2485 | return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP; |
| 2486 | } |
| 2487 | |
| 2488 | /* Wait until LP is stopped. */ |
| 2489 | |
| 2490 | static int |
| 2491 | stop_wait_callback (struct lwp_info *lp) |
| 2492 | { |
| 2493 | struct inferior *inf = find_inferior_ptid (lp->ptid); |
| 2494 | |
| 2495 | /* If this is a vfork parent, bail out, it is not going to report |
| 2496 | any SIGSTOP until the vfork is done with. */ |
| 2497 | if (inf->vfork_child != NULL) |
| 2498 | return 0; |
| 2499 | |
| 2500 | if (!lp->stopped) |
| 2501 | { |
| 2502 | int status; |
| 2503 | |
| 2504 | status = wait_lwp (lp); |
| 2505 | if (status == 0) |
| 2506 | return 0; |
| 2507 | |
| 2508 | if (lp->ignore_sigint && WIFSTOPPED (status) |
| 2509 | && WSTOPSIG (status) == SIGINT) |
| 2510 | { |
| 2511 | lp->ignore_sigint = 0; |
| 2512 | |
| 2513 | errno = 0; |
| 2514 | ptrace (PTRACE_CONT, lp->ptid.lwp (), 0, 0); |
| 2515 | lp->stopped = 0; |
| 2516 | if (debug_linux_nat) |
| 2517 | fprintf_unfiltered (gdb_stdlog, |
| 2518 | "PTRACE_CONT %s, 0, 0 (%s) " |
| 2519 | "(discarding SIGINT)\n", |
| 2520 | target_pid_to_str (lp->ptid).c_str (), |
| 2521 | errno ? safe_strerror (errno) : "OK"); |
| 2522 | |
| 2523 | return stop_wait_callback (lp); |
| 2524 | } |
| 2525 | |
| 2526 | maybe_clear_ignore_sigint (lp); |
| 2527 | |
| 2528 | if (WSTOPSIG (status) != SIGSTOP) |
| 2529 | { |
| 2530 | /* The thread was stopped with a signal other than SIGSTOP. */ |
| 2531 | |
| 2532 | if (debug_linux_nat) |
| 2533 | fprintf_unfiltered (gdb_stdlog, |
| 2534 | "SWC: Pending event %s in %s\n", |
| 2535 | status_to_str ((int) status), |
| 2536 | target_pid_to_str (lp->ptid).c_str ()); |
| 2537 | |
| 2538 | /* Save the sigtrap event. */ |
| 2539 | lp->status = status; |
| 2540 | gdb_assert (lp->signalled); |
| 2541 | save_stop_reason (lp); |
| 2542 | } |
| 2543 | else |
| 2544 | { |
| 2545 | /* We caught the SIGSTOP that we intended to catch. */ |
| 2546 | |
| 2547 | if (debug_linux_nat) |
| 2548 | fprintf_unfiltered (gdb_stdlog, |
| 2549 | "SWC: Expected SIGSTOP caught for %s.\n", |
| 2550 | target_pid_to_str (lp->ptid).c_str ()); |
| 2551 | |
| 2552 | lp->signalled = 0; |
| 2553 | |
| 2554 | /* If we are waiting for this stop so we can report the thread |
| 2555 | stopped then we need to record this status. Otherwise, we can |
| 2556 | now discard this stop event. */ |
| 2557 | if (lp->last_resume_kind == resume_stop) |
| 2558 | { |
| 2559 | lp->status = status; |
| 2560 | save_stop_reason (lp); |
| 2561 | } |
| 2562 | } |
| 2563 | } |
| 2564 | |
| 2565 | return 0; |
| 2566 | } |
| 2567 | |
| 2568 | /* Return non-zero if LP has a wait status pending. Discard the |
| 2569 | pending event and resume the LWP if the event that originally |
| 2570 | caused the stop became uninteresting. */ |
| 2571 | |
| 2572 | static int |
| 2573 | status_callback (struct lwp_info *lp) |
| 2574 | { |
| 2575 | /* Only report a pending wait status if we pretend that this has |
| 2576 | indeed been resumed. */ |
| 2577 | if (!lp->resumed) |
| 2578 | return 0; |
| 2579 | |
| 2580 | if (!lwp_status_pending_p (lp)) |
| 2581 | return 0; |
| 2582 | |
| 2583 | if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT |
| 2584 | || lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT) |
| 2585 | { |
| 2586 | struct regcache *regcache = get_thread_regcache (lp->ptid); |
| 2587 | CORE_ADDR pc; |
| 2588 | int discard = 0; |
| 2589 | |
| 2590 | pc = regcache_read_pc (regcache); |
| 2591 | |
| 2592 | if (pc != lp->stop_pc) |
| 2593 | { |
| 2594 | if (debug_linux_nat) |
| 2595 | fprintf_unfiltered (gdb_stdlog, |
| 2596 | "SC: PC of %s changed. was=%s, now=%s\n", |
| 2597 | target_pid_to_str (lp->ptid).c_str (), |
| 2598 | paddress (target_gdbarch (), lp->stop_pc), |
| 2599 | paddress (target_gdbarch (), pc)); |
| 2600 | discard = 1; |
| 2601 | } |
| 2602 | |
| 2603 | #if !USE_SIGTRAP_SIGINFO |
| 2604 | else if (!breakpoint_inserted_here_p (regcache->aspace (), pc)) |
| 2605 | { |
| 2606 | if (debug_linux_nat) |
| 2607 | fprintf_unfiltered (gdb_stdlog, |
| 2608 | "SC: previous breakpoint of %s, at %s gone\n", |
| 2609 | target_pid_to_str (lp->ptid).c_str (), |
| 2610 | paddress (target_gdbarch (), lp->stop_pc)); |
| 2611 | |
| 2612 | discard = 1; |
| 2613 | } |
| 2614 | #endif |
| 2615 | |
| 2616 | if (discard) |
| 2617 | { |
| 2618 | if (debug_linux_nat) |
| 2619 | fprintf_unfiltered (gdb_stdlog, |
| 2620 | "SC: pending event of %s cancelled.\n", |
| 2621 | target_pid_to_str (lp->ptid).c_str ()); |
| 2622 | |
| 2623 | lp->status = 0; |
| 2624 | linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0); |
| 2625 | return 0; |
| 2626 | } |
| 2627 | } |
| 2628 | |
| 2629 | return 1; |
| 2630 | } |
| 2631 | |
| 2632 | /* Count the LWP's that have had events. */ |
| 2633 | |
| 2634 | static int |
| 2635 | count_events_callback (struct lwp_info *lp, int *count) |
| 2636 | { |
| 2637 | gdb_assert (count != NULL); |
| 2638 | |
| 2639 | /* Select only resumed LWPs that have an event pending. */ |
| 2640 | if (lp->resumed && lwp_status_pending_p (lp)) |
| 2641 | (*count)++; |
| 2642 | |
| 2643 | return 0; |
| 2644 | } |
| 2645 | |
| 2646 | /* Select the LWP (if any) that is currently being single-stepped. */ |
| 2647 | |
| 2648 | static int |
| 2649 | select_singlestep_lwp_callback (struct lwp_info *lp) |
| 2650 | { |
| 2651 | if (lp->last_resume_kind == resume_step |
| 2652 | && lp->status != 0) |
| 2653 | return 1; |
| 2654 | else |
| 2655 | return 0; |
| 2656 | } |
| 2657 | |
| 2658 | /* Returns true if LP has a status pending. */ |
| 2659 | |
| 2660 | static int |
| 2661 | lwp_status_pending_p (struct lwp_info *lp) |
| 2662 | { |
| 2663 | /* We check for lp->waitstatus in addition to lp->status, because we |
| 2664 | can have pending process exits recorded in lp->status and |
| 2665 | W_EXITCODE(0,0) happens to be 0. */ |
| 2666 | return lp->status != 0 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE; |
| 2667 | } |
| 2668 | |
| 2669 | /* Select the Nth LWP that has had an event. */ |
| 2670 | |
| 2671 | static int |
| 2672 | select_event_lwp_callback (struct lwp_info *lp, int *selector) |
| 2673 | { |
| 2674 | gdb_assert (selector != NULL); |
| 2675 | |
| 2676 | /* Select only resumed LWPs that have an event pending. */ |
| 2677 | if (lp->resumed && lwp_status_pending_p (lp)) |
| 2678 | if ((*selector)-- == 0) |
| 2679 | return 1; |
| 2680 | |
| 2681 | return 0; |
| 2682 | } |
| 2683 | |
| 2684 | /* Called when the LWP stopped for a signal/trap. If it stopped for a |
| 2685 | trap check what caused it (breakpoint, watchpoint, trace, etc.), |
| 2686 | and save the result in the LWP's stop_reason field. If it stopped |
| 2687 | for a breakpoint, decrement the PC if necessary on the lwp's |
| 2688 | architecture. */ |
| 2689 | |
| 2690 | static void |
| 2691 | save_stop_reason (struct lwp_info *lp) |
| 2692 | { |
| 2693 | struct regcache *regcache; |
| 2694 | struct gdbarch *gdbarch; |
| 2695 | CORE_ADDR pc; |
| 2696 | CORE_ADDR sw_bp_pc; |
| 2697 | #if USE_SIGTRAP_SIGINFO |
| 2698 | siginfo_t siginfo; |
| 2699 | #endif |
| 2700 | |
| 2701 | gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON); |
| 2702 | gdb_assert (lp->status != 0); |
| 2703 | |
| 2704 | if (!linux_target->low_status_is_event (lp->status)) |
| 2705 | return; |
| 2706 | |
| 2707 | regcache = get_thread_regcache (lp->ptid); |
| 2708 | gdbarch = regcache->arch (); |
| 2709 | |
| 2710 | pc = regcache_read_pc (regcache); |
| 2711 | sw_bp_pc = pc - gdbarch_decr_pc_after_break (gdbarch); |
| 2712 | |
| 2713 | #if USE_SIGTRAP_SIGINFO |
| 2714 | if (linux_nat_get_siginfo (lp->ptid, &siginfo)) |
| 2715 | { |
| 2716 | if (siginfo.si_signo == SIGTRAP) |
| 2717 | { |
| 2718 | if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code) |
| 2719 | && GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code)) |
| 2720 | { |
| 2721 | /* The si_code is ambiguous on this arch -- check debug |
| 2722 | registers. */ |
| 2723 | if (!check_stopped_by_watchpoint (lp)) |
| 2724 | lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT; |
| 2725 | } |
| 2726 | else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code)) |
| 2727 | { |
| 2728 | /* If we determine the LWP stopped for a SW breakpoint, |
| 2729 | trust it. Particularly don't check watchpoint |
| 2730 | registers, because at least on s390, we'd find |
| 2731 | stopped-by-watchpoint as long as there's a watchpoint |
| 2732 | set. */ |
| 2733 | lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT; |
| 2734 | } |
| 2735 | else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code)) |
| 2736 | { |
| 2737 | /* This can indicate either a hardware breakpoint or |
| 2738 | hardware watchpoint. Check debug registers. */ |
| 2739 | if (!check_stopped_by_watchpoint (lp)) |
| 2740 | lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT; |
| 2741 | } |
| 2742 | else if (siginfo.si_code == TRAP_TRACE) |
| 2743 | { |
| 2744 | if (debug_linux_nat) |
| 2745 | fprintf_unfiltered (gdb_stdlog, |
| 2746 | "CSBB: %s stopped by trace\n", |
| 2747 | target_pid_to_str (lp->ptid).c_str ()); |
| 2748 | |
| 2749 | /* We may have single stepped an instruction that |
| 2750 | triggered a watchpoint. In that case, on some |
| 2751 | architectures (such as x86), instead of TRAP_HWBKPT, |
| 2752 | si_code indicates TRAP_TRACE, and we need to check |
| 2753 | the debug registers separately. */ |
| 2754 | check_stopped_by_watchpoint (lp); |
| 2755 | } |
| 2756 | } |
| 2757 | } |
| 2758 | #else |
| 2759 | if ((!lp->step || lp->stop_pc == sw_bp_pc) |
| 2760 | && software_breakpoint_inserted_here_p (regcache->aspace (), |
| 2761 | sw_bp_pc)) |
| 2762 | { |
| 2763 | /* The LWP was either continued, or stepped a software |
| 2764 | breakpoint instruction. */ |
| 2765 | lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT; |
| 2766 | } |
| 2767 | |
| 2768 | if (hardware_breakpoint_inserted_here_p (regcache->aspace (), pc)) |
| 2769 | lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT; |
| 2770 | |
| 2771 | if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON) |
| 2772 | check_stopped_by_watchpoint (lp); |
| 2773 | #endif |
| 2774 | |
| 2775 | if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT) |
| 2776 | { |
| 2777 | if (debug_linux_nat) |
| 2778 | fprintf_unfiltered (gdb_stdlog, |
| 2779 | "CSBB: %s stopped by software breakpoint\n", |
| 2780 | target_pid_to_str (lp->ptid).c_str ()); |
| 2781 | |
| 2782 | /* Back up the PC if necessary. */ |
| 2783 | if (pc != sw_bp_pc) |
| 2784 | regcache_write_pc (regcache, sw_bp_pc); |
| 2785 | |
| 2786 | /* Update this so we record the correct stop PC below. */ |
| 2787 | pc = sw_bp_pc; |
| 2788 | } |
| 2789 | else if (lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT) |
| 2790 | { |
| 2791 | if (debug_linux_nat) |
| 2792 | fprintf_unfiltered (gdb_stdlog, |
| 2793 | "CSBB: %s stopped by hardware breakpoint\n", |
| 2794 | target_pid_to_str (lp->ptid).c_str ()); |
| 2795 | } |
| 2796 | else if (lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT) |
| 2797 | { |
| 2798 | if (debug_linux_nat) |
| 2799 | fprintf_unfiltered (gdb_stdlog, |
| 2800 | "CSBB: %s stopped by hardware watchpoint\n", |
| 2801 | target_pid_to_str (lp->ptid).c_str ()); |
| 2802 | } |
| 2803 | |
| 2804 | lp->stop_pc = pc; |
| 2805 | } |
| 2806 | |
| 2807 | |
| 2808 | /* Returns true if the LWP had stopped for a software breakpoint. */ |
| 2809 | |
| 2810 | bool |
| 2811 | linux_nat_target::stopped_by_sw_breakpoint () |
| 2812 | { |
| 2813 | struct lwp_info *lp = find_lwp_pid (inferior_ptid); |
| 2814 | |
| 2815 | gdb_assert (lp != NULL); |
| 2816 | |
| 2817 | return lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT; |
| 2818 | } |
| 2819 | |
| 2820 | /* Implement the supports_stopped_by_sw_breakpoint method. */ |
| 2821 | |
| 2822 | bool |
| 2823 | linux_nat_target::supports_stopped_by_sw_breakpoint () |
| 2824 | { |
| 2825 | return USE_SIGTRAP_SIGINFO; |
| 2826 | } |
| 2827 | |
| 2828 | /* Returns true if the LWP had stopped for a hardware |
| 2829 | breakpoint/watchpoint. */ |
| 2830 | |
| 2831 | bool |
| 2832 | linux_nat_target::stopped_by_hw_breakpoint () |
| 2833 | { |
| 2834 | struct lwp_info *lp = find_lwp_pid (inferior_ptid); |
| 2835 | |
| 2836 | gdb_assert (lp != NULL); |
| 2837 | |
| 2838 | return lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT; |
| 2839 | } |
| 2840 | |
| 2841 | /* Implement the supports_stopped_by_hw_breakpoint method. */ |
| 2842 | |
| 2843 | bool |
| 2844 | linux_nat_target::supports_stopped_by_hw_breakpoint () |
| 2845 | { |
| 2846 | return USE_SIGTRAP_SIGINFO; |
| 2847 | } |
| 2848 | |
| 2849 | /* Select one LWP out of those that have events pending. */ |
| 2850 | |
| 2851 | static void |
| 2852 | select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status) |
| 2853 | { |
| 2854 | int num_events = 0; |
| 2855 | int random_selector; |
| 2856 | struct lwp_info *event_lp = NULL; |
| 2857 | |
| 2858 | /* Record the wait status for the original LWP. */ |
| 2859 | (*orig_lp)->status = *status; |
| 2860 | |
| 2861 | /* In all-stop, give preference to the LWP that is being |
| 2862 | single-stepped. There will be at most one, and it will be the |
| 2863 | LWP that the core is most interested in. If we didn't do this, |
| 2864 | then we'd have to handle pending step SIGTRAPs somehow in case |
| 2865 | the core later continues the previously-stepped thread, as |
| 2866 | otherwise we'd report the pending SIGTRAP then, and the core, not |
| 2867 | having stepped the thread, wouldn't understand what the trap was |
| 2868 | for, and therefore would report it to the user as a random |
| 2869 | signal. */ |
| 2870 | if (!target_is_non_stop_p ()) |
| 2871 | { |
| 2872 | event_lp = iterate_over_lwps (filter, select_singlestep_lwp_callback); |
| 2873 | if (event_lp != NULL) |
| 2874 | { |
| 2875 | if (debug_linux_nat) |
| 2876 | fprintf_unfiltered (gdb_stdlog, |
| 2877 | "SEL: Select single-step %s\n", |
| 2878 | target_pid_to_str (event_lp->ptid).c_str ()); |
| 2879 | } |
| 2880 | } |
| 2881 | |
| 2882 | if (event_lp == NULL) |
| 2883 | { |
| 2884 | /* Pick one at random, out of those which have had events. */ |
| 2885 | |
| 2886 | /* First see how many events we have. */ |
| 2887 | iterate_over_lwps (filter, |
| 2888 | [&] (struct lwp_info *info) |
| 2889 | { |
| 2890 | return count_events_callback (info, &num_events); |
| 2891 | }); |
| 2892 | gdb_assert (num_events > 0); |
| 2893 | |
| 2894 | /* Now randomly pick a LWP out of those that have had |
| 2895 | events. */ |
| 2896 | random_selector = (int) |
| 2897 | ((num_events * (double) rand ()) / (RAND_MAX + 1.0)); |
| 2898 | |
| 2899 | if (debug_linux_nat && num_events > 1) |
| 2900 | fprintf_unfiltered (gdb_stdlog, |
| 2901 | "SEL: Found %d events, selecting #%d\n", |
| 2902 | num_events, random_selector); |
| 2903 | |
| 2904 | event_lp |
| 2905 | = (iterate_over_lwps |
| 2906 | (filter, |
| 2907 | [&] (struct lwp_info *info) |
| 2908 | { |
| 2909 | return select_event_lwp_callback (info, |
| 2910 | &random_selector); |
| 2911 | })); |
| 2912 | } |
| 2913 | |
| 2914 | if (event_lp != NULL) |
| 2915 | { |
| 2916 | /* Switch the event LWP. */ |
| 2917 | *orig_lp = event_lp; |
| 2918 | *status = event_lp->status; |
| 2919 | } |
| 2920 | |
| 2921 | /* Flush the wait status for the event LWP. */ |
| 2922 | (*orig_lp)->status = 0; |
| 2923 | } |
| 2924 | |
| 2925 | /* Return non-zero if LP has been resumed. */ |
| 2926 | |
| 2927 | static int |
| 2928 | resumed_callback (struct lwp_info *lp) |
| 2929 | { |
| 2930 | return lp->resumed; |
| 2931 | } |
| 2932 | |
| 2933 | /* Check if we should go on and pass this event to common code. |
| 2934 | Return the affected lwp if we are, or NULL otherwise. */ |
| 2935 | |
| 2936 | static struct lwp_info * |
| 2937 | linux_nat_filter_event (int lwpid, int status) |
| 2938 | { |
| 2939 | struct lwp_info *lp; |
| 2940 | int event = linux_ptrace_get_extended_event (status); |
| 2941 | |
| 2942 | lp = find_lwp_pid (ptid_t (lwpid)); |
| 2943 | |
| 2944 | /* Check for stop events reported by a process we didn't already |
| 2945 | know about - anything not already in our LWP list. |
| 2946 | |
| 2947 | If we're expecting to receive stopped processes after |
| 2948 | fork, vfork, and clone events, then we'll just add the |
| 2949 | new one to our list and go back to waiting for the event |
| 2950 | to be reported - the stopped process might be returned |
| 2951 | from waitpid before or after the event is. |
| 2952 | |
| 2953 | But note the case of a non-leader thread exec'ing after the |
| 2954 | leader having exited, and gone from our lists. The non-leader |
| 2955 | thread changes its tid to the tgid. */ |
| 2956 | |
| 2957 | if (WIFSTOPPED (status) && lp == NULL |
| 2958 | && (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC)) |
| 2959 | { |
| 2960 | /* A multi-thread exec after we had seen the leader exiting. */ |
| 2961 | if (debug_linux_nat) |
| 2962 | fprintf_unfiltered (gdb_stdlog, |
| 2963 | "LLW: Re-adding thread group leader LWP %d.\n", |
| 2964 | lwpid); |
| 2965 | |
| 2966 | lp = add_lwp (ptid_t (lwpid, lwpid, 0)); |
| 2967 | lp->stopped = 1; |
| 2968 | lp->resumed = 1; |
| 2969 | add_thread (lp->ptid); |
| 2970 | } |
| 2971 | |
| 2972 | if (WIFSTOPPED (status) && !lp) |
| 2973 | { |
| 2974 | if (debug_linux_nat) |
| 2975 | fprintf_unfiltered (gdb_stdlog, |
| 2976 | "LHEW: saving LWP %ld status %s in stopped_pids list\n", |
| 2977 | (long) lwpid, status_to_str (status)); |
| 2978 | add_to_pid_list (&stopped_pids, lwpid, status); |
| 2979 | return NULL; |
| 2980 | } |
| 2981 | |
| 2982 | /* Make sure we don't report an event for the exit of an LWP not in |
| 2983 | our list, i.e. not part of the current process. This can happen |
| 2984 | if we detach from a program we originally forked and then it |
| 2985 | exits. */ |
| 2986 | if (!WIFSTOPPED (status) && !lp) |
| 2987 | return NULL; |
| 2988 | |
| 2989 | /* This LWP is stopped now. (And if dead, this prevents it from |
| 2990 | ever being continued.) */ |
| 2991 | lp->stopped = 1; |
| 2992 | |
| 2993 | if (WIFSTOPPED (status) && lp->must_set_ptrace_flags) |
| 2994 | { |
| 2995 | struct inferior *inf = find_inferior_pid (lp->ptid.pid ()); |
| 2996 | int options = linux_nat_ptrace_options (inf->attach_flag); |
| 2997 | |
| 2998 | linux_enable_event_reporting (lp->ptid.lwp (), options); |
| 2999 | lp->must_set_ptrace_flags = 0; |
| 3000 | } |
| 3001 | |
| 3002 | /* Handle GNU/Linux's syscall SIGTRAPs. */ |
| 3003 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP) |
| 3004 | { |
| 3005 | /* No longer need the sysgood bit. The ptrace event ends up |
| 3006 | recorded in lp->waitstatus if we care for it. We can carry |
| 3007 | on handling the event like a regular SIGTRAP from here |
| 3008 | on. */ |
| 3009 | status = W_STOPCODE (SIGTRAP); |
| 3010 | if (linux_handle_syscall_trap (lp, 0)) |
| 3011 | return NULL; |
| 3012 | } |
| 3013 | else |
| 3014 | { |
| 3015 | /* Almost all other ptrace-stops are known to be outside of system |
| 3016 | calls, with further exceptions in linux_handle_extended_wait. */ |
| 3017 | lp->syscall_state = TARGET_WAITKIND_IGNORE; |
| 3018 | } |
| 3019 | |
| 3020 | /* Handle GNU/Linux's extended waitstatus for trace events. */ |
| 3021 | if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP |
| 3022 | && linux_is_extended_waitstatus (status)) |
| 3023 | { |
| 3024 | if (debug_linux_nat) |
| 3025 | fprintf_unfiltered (gdb_stdlog, |
| 3026 | "LLW: Handling extended status 0x%06x\n", |
| 3027 | status); |
| 3028 | if (linux_handle_extended_wait (lp, status)) |
| 3029 | return NULL; |
| 3030 | } |
| 3031 | |
| 3032 | /* Check if the thread has exited. */ |
| 3033 | if (WIFEXITED (status) || WIFSIGNALED (status)) |
| 3034 | { |
| 3035 | if (!report_thread_events |
| 3036 | && num_lwps (lp->ptid.pid ()) > 1) |
| 3037 | { |
| 3038 | if (debug_linux_nat) |
| 3039 | fprintf_unfiltered (gdb_stdlog, |
| 3040 | "LLW: %s exited.\n", |
| 3041 | target_pid_to_str (lp->ptid).c_str ()); |
| 3042 | |
| 3043 | /* If there is at least one more LWP, then the exit signal |
| 3044 | was not the end of the debugged application and should be |
| 3045 | ignored. */ |
| 3046 | exit_lwp (lp); |
| 3047 | return NULL; |
| 3048 | } |
| 3049 | |
| 3050 | /* Note that even if the leader was ptrace-stopped, it can still |
| 3051 | exit, if e.g., some other thread brings down the whole |
| 3052 | process (calls `exit'). So don't assert that the lwp is |
| 3053 | resumed. */ |
| 3054 | if (debug_linux_nat) |
| 3055 | fprintf_unfiltered (gdb_stdlog, |
| 3056 | "LWP %ld exited (resumed=%d)\n", |
| 3057 | lp->ptid.lwp (), lp->resumed); |
| 3058 | |
| 3059 | /* Dead LWP's aren't expected to reported a pending sigstop. */ |
| 3060 | lp->signalled = 0; |
| 3061 | |
| 3062 | /* Store the pending event in the waitstatus, because |
| 3063 | W_EXITCODE(0,0) == 0. */ |
| 3064 | store_waitstatus (&lp->waitstatus, status); |
| 3065 | return lp; |
| 3066 | } |
| 3067 | |
| 3068 | /* Make sure we don't report a SIGSTOP that we sent ourselves in |
| 3069 | an attempt to stop an LWP. */ |
| 3070 | if (lp->signalled |
| 3071 | && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP) |
| 3072 | { |
| 3073 | lp->signalled = 0; |
| 3074 | |
| 3075 | if (lp->last_resume_kind == resume_stop) |
| 3076 | { |
| 3077 | if (debug_linux_nat) |
| 3078 | fprintf_unfiltered (gdb_stdlog, |
| 3079 | "LLW: resume_stop SIGSTOP caught for %s.\n", |
| 3080 | target_pid_to_str (lp->ptid).c_str ()); |
| 3081 | } |
| 3082 | else |
| 3083 | { |
| 3084 | /* This is a delayed SIGSTOP. Filter out the event. */ |
| 3085 | |
| 3086 | if (debug_linux_nat) |
| 3087 | fprintf_unfiltered (gdb_stdlog, |
| 3088 | "LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n", |
| 3089 | lp->step ? |
| 3090 | "PTRACE_SINGLESTEP" : "PTRACE_CONT", |
| 3091 | target_pid_to_str (lp->ptid).c_str ()); |
| 3092 | |
| 3093 | linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0); |
| 3094 | gdb_assert (lp->resumed); |
| 3095 | return NULL; |
| 3096 | } |
| 3097 | } |
| 3098 | |
| 3099 | /* Make sure we don't report a SIGINT that we have already displayed |
| 3100 | for another thread. */ |
| 3101 | if (lp->ignore_sigint |
| 3102 | && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT) |
| 3103 | { |
| 3104 | if (debug_linux_nat) |
| 3105 | fprintf_unfiltered (gdb_stdlog, |
| 3106 | "LLW: Delayed SIGINT caught for %s.\n", |
| 3107 | target_pid_to_str (lp->ptid).c_str ()); |
| 3108 | |
| 3109 | /* This is a delayed SIGINT. */ |
| 3110 | lp->ignore_sigint = 0; |
| 3111 | |
| 3112 | linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0); |
| 3113 | if (debug_linux_nat) |
| 3114 | fprintf_unfiltered (gdb_stdlog, |
| 3115 | "LLW: %s %s, 0, 0 (discard SIGINT)\n", |
| 3116 | lp->step ? |
| 3117 | "PTRACE_SINGLESTEP" : "PTRACE_CONT", |
| 3118 | target_pid_to_str (lp->ptid).c_str ()); |
| 3119 | gdb_assert (lp->resumed); |
| 3120 | |
| 3121 | /* Discard the event. */ |
| 3122 | return NULL; |
| 3123 | } |
| 3124 | |
| 3125 | /* Don't report signals that GDB isn't interested in, such as |
| 3126 | signals that are neither printed nor stopped upon. Stopping all |
| 3127 | threads can be a bit time-consuming so if we want decent |
| 3128 | performance with heavily multi-threaded programs, especially when |
| 3129 | they're using a high frequency timer, we'd better avoid it if we |
| 3130 | can. */ |
| 3131 | if (WIFSTOPPED (status)) |
| 3132 | { |
| 3133 | enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status)); |
| 3134 | |
| 3135 | if (!target_is_non_stop_p ()) |
| 3136 | { |
| 3137 | /* Only do the below in all-stop, as we currently use SIGSTOP |
| 3138 | to implement target_stop (see linux_nat_stop) in |
| 3139 | non-stop. */ |
| 3140 | if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0) |
| 3141 | { |
| 3142 | /* If ^C/BREAK is typed at the tty/console, SIGINT gets |
| 3143 | forwarded to the entire process group, that is, all LWPs |
| 3144 | will receive it - unless they're using CLONE_THREAD to |
| 3145 | share signals. Since we only want to report it once, we |
| 3146 | mark it as ignored for all LWPs except this one. */ |
| 3147 | iterate_over_lwps (ptid_t (lp->ptid.pid ()), set_ignore_sigint); |
| 3148 | lp->ignore_sigint = 0; |
| 3149 | } |
| 3150 | else |
| 3151 | maybe_clear_ignore_sigint (lp); |
| 3152 | } |
| 3153 | |
| 3154 | /* When using hardware single-step, we need to report every signal. |
| 3155 | Otherwise, signals in pass_mask may be short-circuited |
| 3156 | except signals that might be caused by a breakpoint. */ |
| 3157 | if (!lp->step |
| 3158 | && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status)) |
| 3159 | && !linux_wstatus_maybe_breakpoint (status)) |
| 3160 | { |
| 3161 | linux_resume_one_lwp (lp, lp->step, signo); |
| 3162 | if (debug_linux_nat) |
| 3163 | fprintf_unfiltered (gdb_stdlog, |
| 3164 | "LLW: %s %s, %s (preempt 'handle')\n", |
| 3165 | lp->step ? |
| 3166 | "PTRACE_SINGLESTEP" : "PTRACE_CONT", |
| 3167 | target_pid_to_str (lp->ptid).c_str (), |
| 3168 | (signo != GDB_SIGNAL_0 |
| 3169 | ? strsignal (gdb_signal_to_host (signo)) |
| 3170 | : "0")); |
| 3171 | return NULL; |
| 3172 | } |
| 3173 | } |
| 3174 | |
| 3175 | /* An interesting event. */ |
| 3176 | gdb_assert (lp); |
| 3177 | lp->status = status; |
| 3178 | save_stop_reason (lp); |
| 3179 | return lp; |
| 3180 | } |
| 3181 | |
| 3182 | /* Detect zombie thread group leaders, and "exit" them. We can't reap |
| 3183 | their exits until all other threads in the group have exited. */ |
| 3184 | |
| 3185 | static void |
| 3186 | check_zombie_leaders (void) |
| 3187 | { |
| 3188 | for (inferior *inf : all_inferiors ()) |
| 3189 | { |
| 3190 | struct lwp_info *leader_lp; |
| 3191 | |
| 3192 | if (inf->pid == 0) |
| 3193 | continue; |
| 3194 | |
| 3195 | leader_lp = find_lwp_pid (ptid_t (inf->pid)); |
| 3196 | if (leader_lp != NULL |
| 3197 | /* Check if there are other threads in the group, as we may |
| 3198 | have raced with the inferior simply exiting. */ |
| 3199 | && num_lwps (inf->pid) > 1 |
| 3200 | && linux_proc_pid_is_zombie (inf->pid)) |
| 3201 | { |
| 3202 | if (debug_linux_nat) |
| 3203 | fprintf_unfiltered (gdb_stdlog, |
| 3204 | "CZL: Thread group leader %d zombie " |
| 3205 | "(it exited, or another thread execd).\n", |
| 3206 | inf->pid); |
| 3207 | |
| 3208 | /* A leader zombie can mean one of two things: |
| 3209 | |
| 3210 | - It exited, and there's an exit status pending |
| 3211 | available, or only the leader exited (not the whole |
| 3212 | program). In the latter case, we can't waitpid the |
| 3213 | leader's exit status until all other threads are gone. |
| 3214 | |
| 3215 | - There are 3 or more threads in the group, and a thread |
| 3216 | other than the leader exec'd. See comments on exec |
| 3217 | events at the top of the file. We could try |
| 3218 | distinguishing the exit and exec cases, by waiting once |
| 3219 | more, and seeing if something comes out, but it doesn't |
| 3220 | sound useful. The previous leader _does_ go away, and |
| 3221 | we'll re-add the new one once we see the exec event |
| 3222 | (which is just the same as what would happen if the |
| 3223 | previous leader did exit voluntarily before some other |
| 3224 | thread execs). */ |
| 3225 | |
| 3226 | if (debug_linux_nat) |
| 3227 | fprintf_unfiltered (gdb_stdlog, |
| 3228 | "CZL: Thread group leader %d vanished.\n", |
| 3229 | inf->pid); |
| 3230 | exit_lwp (leader_lp); |
| 3231 | } |
| 3232 | } |
| 3233 | } |
| 3234 | |
| 3235 | /* Convenience function that is called when the kernel reports an exit |
| 3236 | event. This decides whether to report the event to GDB as a |
| 3237 | process exit event, a thread exit event, or to suppress the |
| 3238 | event. */ |
| 3239 | |
| 3240 | static ptid_t |
| 3241 | filter_exit_event (struct lwp_info *event_child, |
| 3242 | struct target_waitstatus *ourstatus) |
| 3243 | { |
| 3244 | ptid_t ptid = event_child->ptid; |
| 3245 | |
| 3246 | if (num_lwps (ptid.pid ()) > 1) |
| 3247 | { |
| 3248 | if (report_thread_events) |
| 3249 | ourstatus->kind = TARGET_WAITKIND_THREAD_EXITED; |
| 3250 | else |
| 3251 | ourstatus->kind = TARGET_WAITKIND_IGNORE; |
| 3252 | |
| 3253 | exit_lwp (event_child); |
| 3254 | } |
| 3255 | |
| 3256 | return ptid; |
| 3257 | } |
| 3258 | |
| 3259 | static ptid_t |
| 3260 | linux_nat_wait_1 (ptid_t ptid, struct target_waitstatus *ourstatus, |
| 3261 | int target_options) |
| 3262 | { |
| 3263 | sigset_t prev_mask; |
| 3264 | enum resume_kind last_resume_kind; |
| 3265 | struct lwp_info *lp; |
| 3266 | int status; |
| 3267 | |
| 3268 | if (debug_linux_nat) |
| 3269 | fprintf_unfiltered (gdb_stdlog, "LLW: enter\n"); |
| 3270 | |
| 3271 | /* The first time we get here after starting a new inferior, we may |
| 3272 | not have added it to the LWP list yet - this is the earliest |
| 3273 | moment at which we know its PID. */ |
| 3274 | if (inferior_ptid.is_pid ()) |
| 3275 | { |
| 3276 | /* Upgrade the main thread's ptid. */ |
| 3277 | thread_change_ptid (inferior_ptid, |
| 3278 | ptid_t (inferior_ptid.pid (), |
| 3279 | inferior_ptid.pid (), 0)); |
| 3280 | |
| 3281 | lp = add_initial_lwp (inferior_ptid); |
| 3282 | lp->resumed = 1; |
| 3283 | } |
| 3284 | |
| 3285 | /* Make sure SIGCHLD is blocked until the sigsuspend below. */ |
| 3286 | block_child_signals (&prev_mask); |
| 3287 | |
| 3288 | /* First check if there is a LWP with a wait status pending. */ |
| 3289 | lp = iterate_over_lwps (ptid, status_callback); |
| 3290 | if (lp != NULL) |
| 3291 | { |
| 3292 | if (debug_linux_nat) |
| 3293 | fprintf_unfiltered (gdb_stdlog, |
| 3294 | "LLW: Using pending wait status %s for %s.\n", |
| 3295 | status_to_str (lp->status), |
| 3296 | target_pid_to_str (lp->ptid).c_str ()); |
| 3297 | } |
| 3298 | |
| 3299 | /* But if we don't find a pending event, we'll have to wait. Always |
| 3300 | pull all events out of the kernel. We'll randomly select an |
| 3301 | event LWP out of all that have events, to prevent starvation. */ |
| 3302 | |
| 3303 | while (lp == NULL) |
| 3304 | { |
| 3305 | pid_t lwpid; |
| 3306 | |
| 3307 | /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace |
| 3308 | quirks: |
| 3309 | |
| 3310 | - If the thread group leader exits while other threads in the |
| 3311 | thread group still exist, waitpid(TGID, ...) hangs. That |
| 3312 | waitpid won't return an exit status until the other threads |
| 3313 | in the group are reapped. |
| 3314 | |
| 3315 | - When a non-leader thread execs, that thread just vanishes |
| 3316 | without reporting an exit (so we'd hang if we waited for it |
| 3317 | explicitly in that case). The exec event is reported to |
| 3318 | the TGID pid. */ |
| 3319 | |
| 3320 | errno = 0; |
| 3321 | lwpid = my_waitpid (-1, &status, __WALL | WNOHANG); |
| 3322 | |
| 3323 | if (debug_linux_nat) |
| 3324 | fprintf_unfiltered (gdb_stdlog, |
| 3325 | "LNW: waitpid(-1, ...) returned %d, %s\n", |
| 3326 | lwpid, errno ? safe_strerror (errno) : "ERRNO-OK"); |
| 3327 | |
| 3328 | if (lwpid > 0) |
| 3329 | { |
| 3330 | if (debug_linux_nat) |
| 3331 | { |
| 3332 | fprintf_unfiltered (gdb_stdlog, |
| 3333 | "LLW: waitpid %ld received %s\n", |
| 3334 | (long) lwpid, status_to_str (status)); |
| 3335 | } |
| 3336 | |
| 3337 | linux_nat_filter_event (lwpid, status); |
| 3338 | /* Retry until nothing comes out of waitpid. A single |
| 3339 | SIGCHLD can indicate more than one child stopped. */ |
| 3340 | continue; |
| 3341 | } |
| 3342 | |
| 3343 | /* Now that we've pulled all events out of the kernel, resume |
| 3344 | LWPs that don't have an interesting event to report. */ |
| 3345 | iterate_over_lwps (minus_one_ptid, |
| 3346 | [] (struct lwp_info *info) |
| 3347 | { |
| 3348 | return resume_stopped_resumed_lwps (info, minus_one_ptid); |
| 3349 | }); |
| 3350 | |
| 3351 | /* ... and find an LWP with a status to report to the core, if |
| 3352 | any. */ |
| 3353 | lp = iterate_over_lwps (ptid, status_callback); |
| 3354 | if (lp != NULL) |
| 3355 | break; |
| 3356 | |
| 3357 | /* Check for zombie thread group leaders. Those can't be reaped |
| 3358 | until all other threads in the thread group are. */ |
| 3359 | check_zombie_leaders (); |
| 3360 | |
| 3361 | /* If there are no resumed children left, bail. We'd be stuck |
| 3362 | forever in the sigsuspend call below otherwise. */ |
| 3363 | if (iterate_over_lwps (ptid, resumed_callback) == NULL) |
| 3364 | { |
| 3365 | if (debug_linux_nat) |
| 3366 | fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n"); |
| 3367 | |
| 3368 | ourstatus->kind = TARGET_WAITKIND_NO_RESUMED; |
| 3369 | |
| 3370 | restore_child_signals_mask (&prev_mask); |
| 3371 | return minus_one_ptid; |
| 3372 | } |
| 3373 | |
| 3374 | /* No interesting event to report to the core. */ |
| 3375 | |
| 3376 | if (target_options & TARGET_WNOHANG) |
| 3377 | { |
| 3378 | if (debug_linux_nat) |
| 3379 | fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n"); |
| 3380 | |
| 3381 | ourstatus->kind = TARGET_WAITKIND_IGNORE; |
| 3382 | restore_child_signals_mask (&prev_mask); |
| 3383 | return minus_one_ptid; |
| 3384 | } |
| 3385 | |
| 3386 | /* We shouldn't end up here unless we want to try again. */ |
| 3387 | gdb_assert (lp == NULL); |
| 3388 | |
| 3389 | /* Block until we get an event reported with SIGCHLD. */ |
| 3390 | wait_for_signal (); |
| 3391 | } |
| 3392 | |
| 3393 | gdb_assert (lp); |
| 3394 | |
| 3395 | status = lp->status; |
| 3396 | lp->status = 0; |
| 3397 | |
| 3398 | if (!target_is_non_stop_p ()) |
| 3399 | { |
| 3400 | /* Now stop all other LWP's ... */ |
| 3401 | iterate_over_lwps (minus_one_ptid, stop_callback); |
| 3402 | |
| 3403 | /* ... and wait until all of them have reported back that |
| 3404 | they're no longer running. */ |
| 3405 | iterate_over_lwps (minus_one_ptid, stop_wait_callback); |
| 3406 | } |
| 3407 | |
| 3408 | /* If we're not waiting for a specific LWP, choose an event LWP from |
| 3409 | among those that have had events. Giving equal priority to all |
| 3410 | LWPs that have had events helps prevent starvation. */ |
| 3411 | if (ptid == minus_one_ptid || ptid.is_pid ()) |
| 3412 | select_event_lwp (ptid, &lp, &status); |
| 3413 | |
| 3414 | gdb_assert (lp != NULL); |
| 3415 | |
| 3416 | /* Now that we've selected our final event LWP, un-adjust its PC if |
| 3417 | it was a software breakpoint, and we can't reliably support the |
| 3418 | "stopped by software breakpoint" stop reason. */ |
| 3419 | if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT |
| 3420 | && !USE_SIGTRAP_SIGINFO) |
| 3421 | { |
| 3422 | struct regcache *regcache = get_thread_regcache (lp->ptid); |
| 3423 | struct gdbarch *gdbarch = regcache->arch (); |
| 3424 | int decr_pc = gdbarch_decr_pc_after_break (gdbarch); |
| 3425 | |
| 3426 | if (decr_pc != 0) |
| 3427 | { |
| 3428 | CORE_ADDR pc; |
| 3429 | |
| 3430 | pc = regcache_read_pc (regcache); |
| 3431 | regcache_write_pc (regcache, pc + decr_pc); |
| 3432 | } |
| 3433 | } |
| 3434 | |
| 3435 | /* We'll need this to determine whether to report a SIGSTOP as |
| 3436 | GDB_SIGNAL_0. Need to take a copy because resume_clear_callback |
| 3437 | clears it. */ |
| 3438 | last_resume_kind = lp->last_resume_kind; |
| 3439 | |
| 3440 | if (!target_is_non_stop_p ()) |
| 3441 | { |
| 3442 | /* In all-stop, from the core's perspective, all LWPs are now |
| 3443 | stopped until a new resume action is sent over. */ |
| 3444 | iterate_over_lwps (minus_one_ptid, resume_clear_callback); |
| 3445 | } |
| 3446 | else |
| 3447 | { |
| 3448 | resume_clear_callback (lp); |
| 3449 | } |
| 3450 | |
| 3451 | if (linux_target->low_status_is_event (status)) |
| 3452 | { |
| 3453 | if (debug_linux_nat) |
| 3454 | fprintf_unfiltered (gdb_stdlog, |
| 3455 | "LLW: trap ptid is %s.\n", |
| 3456 | target_pid_to_str (lp->ptid).c_str ()); |
| 3457 | } |
| 3458 | |
| 3459 | if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE) |
| 3460 | { |
| 3461 | *ourstatus = lp->waitstatus; |
| 3462 | lp->waitstatus.kind = TARGET_WAITKIND_IGNORE; |
| 3463 | } |
| 3464 | else |
| 3465 | store_waitstatus (ourstatus, status); |
| 3466 | |
| 3467 | if (debug_linux_nat) |
| 3468 | fprintf_unfiltered (gdb_stdlog, "LLW: exit\n"); |
| 3469 | |
| 3470 | restore_child_signals_mask (&prev_mask); |
| 3471 | |
| 3472 | if (last_resume_kind == resume_stop |
| 3473 | && ourstatus->kind == TARGET_WAITKIND_STOPPED |
| 3474 | && WSTOPSIG (status) == SIGSTOP) |
| 3475 | { |
| 3476 | /* A thread that has been requested to stop by GDB with |
| 3477 | target_stop, and it stopped cleanly, so report as SIG0. The |
| 3478 | use of SIGSTOP is an implementation detail. */ |
| 3479 | ourstatus->value.sig = GDB_SIGNAL_0; |
| 3480 | } |
| 3481 | |
| 3482 | if (ourstatus->kind == TARGET_WAITKIND_EXITED |
| 3483 | || ourstatus->kind == TARGET_WAITKIND_SIGNALLED) |
| 3484 | lp->core = -1; |
| 3485 | else |
| 3486 | lp->core = linux_common_core_of_thread (lp->ptid); |
| 3487 | |
| 3488 | if (ourstatus->kind == TARGET_WAITKIND_EXITED) |
| 3489 | return filter_exit_event (lp, ourstatus); |
| 3490 | |
| 3491 | return lp->ptid; |
| 3492 | } |
| 3493 | |
| 3494 | /* Resume LWPs that are currently stopped without any pending status |
| 3495 | to report, but are resumed from the core's perspective. */ |
| 3496 | |
| 3497 | static int |
| 3498 | resume_stopped_resumed_lwps (struct lwp_info *lp, const ptid_t wait_ptid) |
| 3499 | { |
| 3500 | if (!lp->stopped) |
| 3501 | { |
| 3502 | if (debug_linux_nat) |
| 3503 | fprintf_unfiltered (gdb_stdlog, |
| 3504 | "RSRL: NOT resuming LWP %s, not stopped\n", |
| 3505 | target_pid_to_str (lp->ptid).c_str ()); |
| 3506 | } |
| 3507 | else if (!lp->resumed) |
| 3508 | { |
| 3509 | if (debug_linux_nat) |
| 3510 | fprintf_unfiltered (gdb_stdlog, |
| 3511 | "RSRL: NOT resuming LWP %s, not resumed\n", |
| 3512 | target_pid_to_str (lp->ptid).c_str ()); |
| 3513 | } |
| 3514 | else if (lwp_status_pending_p (lp)) |
| 3515 | { |
| 3516 | if (debug_linux_nat) |
| 3517 | fprintf_unfiltered (gdb_stdlog, |
| 3518 | "RSRL: NOT resuming LWP %s, has pending status\n", |
| 3519 | target_pid_to_str (lp->ptid).c_str ()); |
| 3520 | } |
| 3521 | else |
| 3522 | { |
| 3523 | struct regcache *regcache = get_thread_regcache (lp->ptid); |
| 3524 | struct gdbarch *gdbarch = regcache->arch (); |
| 3525 | |
| 3526 | try |
| 3527 | { |
| 3528 | CORE_ADDR pc = regcache_read_pc (regcache); |
| 3529 | int leave_stopped = 0; |
| 3530 | |
| 3531 | /* Don't bother if there's a breakpoint at PC that we'd hit |
| 3532 | immediately, and we're not waiting for this LWP. */ |
| 3533 | if (!lp->ptid.matches (wait_ptid)) |
| 3534 | { |
| 3535 | if (breakpoint_inserted_here_p (regcache->aspace (), pc)) |
| 3536 | leave_stopped = 1; |
| 3537 | } |
| 3538 | |
| 3539 | if (!leave_stopped) |
| 3540 | { |
| 3541 | if (debug_linux_nat) |
| 3542 | fprintf_unfiltered (gdb_stdlog, |
| 3543 | "RSRL: resuming stopped-resumed LWP %s at " |
| 3544 | "%s: step=%d\n", |
| 3545 | target_pid_to_str (lp->ptid).c_str (), |
| 3546 | paddress (gdbarch, pc), |
| 3547 | lp->step); |
| 3548 | |
| 3549 | linux_resume_one_lwp_throw (lp, lp->step, GDB_SIGNAL_0); |
| 3550 | } |
| 3551 | } |
| 3552 | catch (const gdb_exception_error &ex) |
| 3553 | { |
| 3554 | if (!check_ptrace_stopped_lwp_gone (lp)) |
| 3555 | throw; |
| 3556 | } |
| 3557 | } |
| 3558 | |
| 3559 | return 0; |
| 3560 | } |
| 3561 | |
| 3562 | ptid_t |
| 3563 | linux_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus, |
| 3564 | int target_options) |
| 3565 | { |
| 3566 | ptid_t event_ptid; |
| 3567 | |
| 3568 | if (debug_linux_nat) |
| 3569 | { |
| 3570 | std::string options_string = target_options_to_string (target_options); |
| 3571 | fprintf_unfiltered (gdb_stdlog, |
| 3572 | "linux_nat_wait: [%s], [%s]\n", |
| 3573 | target_pid_to_str (ptid).c_str (), |
| 3574 | options_string.c_str ()); |
| 3575 | } |
| 3576 | |
| 3577 | /* Flush the async file first. */ |
| 3578 | if (target_is_async_p ()) |
| 3579 | async_file_flush (); |
| 3580 | |
| 3581 | /* Resume LWPs that are currently stopped without any pending status |
| 3582 | to report, but are resumed from the core's perspective. LWPs get |
| 3583 | in this state if we find them stopping at a time we're not |
| 3584 | interested in reporting the event (target_wait on a |
| 3585 | specific_process, for example, see linux_nat_wait_1), and |
| 3586 | meanwhile the event became uninteresting. Don't bother resuming |
| 3587 | LWPs we're not going to wait for if they'd stop immediately. */ |
| 3588 | if (target_is_non_stop_p ()) |
| 3589 | iterate_over_lwps (minus_one_ptid, |
| 3590 | [=] (struct lwp_info *info) |
| 3591 | { |
| 3592 | return resume_stopped_resumed_lwps (info, ptid); |
| 3593 | }); |
| 3594 | |
| 3595 | event_ptid = linux_nat_wait_1 (ptid, ourstatus, target_options); |
| 3596 | |
| 3597 | /* If we requested any event, and something came out, assume there |
| 3598 | may be more. If we requested a specific lwp or process, also |
| 3599 | assume there may be more. */ |
| 3600 | if (target_is_async_p () |
| 3601 | && ((ourstatus->kind != TARGET_WAITKIND_IGNORE |
| 3602 | && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED) |
| 3603 | || ptid != minus_one_ptid)) |
| 3604 | async_file_mark (); |
| 3605 | |
| 3606 | return event_ptid; |
| 3607 | } |
| 3608 | |
| 3609 | /* Kill one LWP. */ |
| 3610 | |
| 3611 | static void |
| 3612 | kill_one_lwp (pid_t pid) |
| 3613 | { |
| 3614 | /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */ |
| 3615 | |
| 3616 | errno = 0; |
| 3617 | kill_lwp (pid, SIGKILL); |
| 3618 | if (debug_linux_nat) |
| 3619 | { |
| 3620 | int save_errno = errno; |
| 3621 | |
| 3622 | fprintf_unfiltered (gdb_stdlog, |
| 3623 | "KC: kill (SIGKILL) %ld, 0, 0 (%s)\n", (long) pid, |
| 3624 | save_errno ? safe_strerror (save_errno) : "OK"); |
| 3625 | } |
| 3626 | |
| 3627 | /* Some kernels ignore even SIGKILL for processes under ptrace. */ |
| 3628 | |
| 3629 | errno = 0; |
| 3630 | ptrace (PTRACE_KILL, pid, 0, 0); |
| 3631 | if (debug_linux_nat) |
| 3632 | { |
| 3633 | int save_errno = errno; |
| 3634 | |
| 3635 | fprintf_unfiltered (gdb_stdlog, |
| 3636 | "KC: PTRACE_KILL %ld, 0, 0 (%s)\n", (long) pid, |
| 3637 | save_errno ? safe_strerror (save_errno) : "OK"); |
| 3638 | } |
| 3639 | } |
| 3640 | |
| 3641 | /* Wait for an LWP to die. */ |
| 3642 | |
| 3643 | static void |
| 3644 | kill_wait_one_lwp (pid_t pid) |
| 3645 | { |
| 3646 | pid_t res; |
| 3647 | |
| 3648 | /* We must make sure that there are no pending events (delayed |
| 3649 | SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current |
| 3650 | program doesn't interfere with any following debugging session. */ |
| 3651 | |
| 3652 | do |
| 3653 | { |
| 3654 | res = my_waitpid (pid, NULL, __WALL); |
| 3655 | if (res != (pid_t) -1) |
| 3656 | { |
| 3657 | if (debug_linux_nat) |
| 3658 | fprintf_unfiltered (gdb_stdlog, |
| 3659 | "KWC: wait %ld received unknown.\n", |
| 3660 | (long) pid); |
| 3661 | /* The Linux kernel sometimes fails to kill a thread |
| 3662 | completely after PTRACE_KILL; that goes from the stop |
| 3663 | point in do_fork out to the one in get_signal_to_deliver |
| 3664 | and waits again. So kill it again. */ |
| 3665 | kill_one_lwp (pid); |
| 3666 | } |
| 3667 | } |
| 3668 | while (res == pid); |
| 3669 | |
| 3670 | gdb_assert (res == -1 && errno == ECHILD); |
| 3671 | } |
| 3672 | |
| 3673 | /* Callback for iterate_over_lwps. */ |
| 3674 | |
| 3675 | static int |
| 3676 | kill_callback (struct lwp_info *lp) |
| 3677 | { |
| 3678 | kill_one_lwp (lp->ptid.lwp ()); |
| 3679 | return 0; |
| 3680 | } |
| 3681 | |
| 3682 | /* Callback for iterate_over_lwps. */ |
| 3683 | |
| 3684 | static int |
| 3685 | kill_wait_callback (struct lwp_info *lp) |
| 3686 | { |
| 3687 | kill_wait_one_lwp (lp->ptid.lwp ()); |
| 3688 | return 0; |
| 3689 | } |
| 3690 | |
| 3691 | /* Kill the fork children of any threads of inferior INF that are |
| 3692 | stopped at a fork event. */ |
| 3693 | |
| 3694 | static void |
| 3695 | kill_unfollowed_fork_children (struct inferior *inf) |
| 3696 | { |
| 3697 | for (thread_info *thread : inf->non_exited_threads ()) |
| 3698 | { |
| 3699 | struct target_waitstatus *ws = &thread->pending_follow; |
| 3700 | |
| 3701 | if (ws->kind == TARGET_WAITKIND_FORKED |
| 3702 | || ws->kind == TARGET_WAITKIND_VFORKED) |
| 3703 | { |
| 3704 | ptid_t child_ptid = ws->value.related_pid; |
| 3705 | int child_pid = child_ptid.pid (); |
| 3706 | int child_lwp = child_ptid.lwp (); |
| 3707 | |
| 3708 | kill_one_lwp (child_lwp); |
| 3709 | kill_wait_one_lwp (child_lwp); |
| 3710 | |
| 3711 | /* Let the arch-specific native code know this process is |
| 3712 | gone. */ |
| 3713 | linux_target->low_forget_process (child_pid); |
| 3714 | } |
| 3715 | } |
| 3716 | } |
| 3717 | |
| 3718 | void |
| 3719 | linux_nat_target::kill () |
| 3720 | { |
| 3721 | /* If we're stopped while forking and we haven't followed yet, |
| 3722 | kill the other task. We need to do this first because the |
| 3723 | parent will be sleeping if this is a vfork. */ |
| 3724 | kill_unfollowed_fork_children (current_inferior ()); |
| 3725 | |
| 3726 | if (forks_exist_p ()) |
| 3727 | linux_fork_killall (); |
| 3728 | else |
| 3729 | { |
| 3730 | ptid_t ptid = ptid_t (inferior_ptid.pid ()); |
| 3731 | |
| 3732 | /* Stop all threads before killing them, since ptrace requires |
| 3733 | that the thread is stopped to sucessfully PTRACE_KILL. */ |
| 3734 | iterate_over_lwps (ptid, stop_callback); |
| 3735 | /* ... and wait until all of them have reported back that |
| 3736 | they're no longer running. */ |
| 3737 | iterate_over_lwps (ptid, stop_wait_callback); |
| 3738 | |
| 3739 | /* Kill all LWP's ... */ |
| 3740 | iterate_over_lwps (ptid, kill_callback); |
| 3741 | |
| 3742 | /* ... and wait until we've flushed all events. */ |
| 3743 | iterate_over_lwps (ptid, kill_wait_callback); |
| 3744 | } |
| 3745 | |
| 3746 | target_mourn_inferior (inferior_ptid); |
| 3747 | } |
| 3748 | |
| 3749 | void |
| 3750 | linux_nat_target::mourn_inferior () |
| 3751 | { |
| 3752 | int pid = inferior_ptid.pid (); |
| 3753 | |
| 3754 | purge_lwp_list (pid); |
| 3755 | |
| 3756 | if (! forks_exist_p ()) |
| 3757 | /* Normal case, no other forks available. */ |
| 3758 | inf_ptrace_target::mourn_inferior (); |
| 3759 | else |
| 3760 | /* Multi-fork case. The current inferior_ptid has exited, but |
| 3761 | there are other viable forks to debug. Delete the exiting |
| 3762 | one and context-switch to the first available. */ |
| 3763 | linux_fork_mourn_inferior (); |
| 3764 | |
| 3765 | /* Let the arch-specific native code know this process is gone. */ |
| 3766 | linux_target->low_forget_process (pid); |
| 3767 | } |
| 3768 | |
| 3769 | /* Convert a native/host siginfo object, into/from the siginfo in the |
| 3770 | layout of the inferiors' architecture. */ |
| 3771 | |
| 3772 | static void |
| 3773 | siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction) |
| 3774 | { |
| 3775 | /* If the low target didn't do anything, then just do a straight |
| 3776 | memcpy. */ |
| 3777 | if (!linux_target->low_siginfo_fixup (siginfo, inf_siginfo, direction)) |
| 3778 | { |
| 3779 | if (direction == 1) |
| 3780 | memcpy (siginfo, inf_siginfo, sizeof (siginfo_t)); |
| 3781 | else |
| 3782 | memcpy (inf_siginfo, siginfo, sizeof (siginfo_t)); |
| 3783 | } |
| 3784 | } |
| 3785 | |
| 3786 | static enum target_xfer_status |
| 3787 | linux_xfer_siginfo (enum target_object object, |
| 3788 | const char *annex, gdb_byte *readbuf, |
| 3789 | const gdb_byte *writebuf, ULONGEST offset, ULONGEST len, |
| 3790 | ULONGEST *xfered_len) |
| 3791 | { |
| 3792 | int pid; |
| 3793 | siginfo_t siginfo; |
| 3794 | gdb_byte inf_siginfo[sizeof (siginfo_t)]; |
| 3795 | |
| 3796 | gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO); |
| 3797 | gdb_assert (readbuf || writebuf); |
| 3798 | |
| 3799 | pid = inferior_ptid.lwp (); |
| 3800 | if (pid == 0) |
| 3801 | pid = inferior_ptid.pid (); |
| 3802 | |
| 3803 | if (offset > sizeof (siginfo)) |
| 3804 | return TARGET_XFER_E_IO; |
| 3805 | |
| 3806 | errno = 0; |
| 3807 | ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo); |
| 3808 | if (errno != 0) |
| 3809 | return TARGET_XFER_E_IO; |
| 3810 | |
| 3811 | /* When GDB is built as a 64-bit application, ptrace writes into |
| 3812 | SIGINFO an object with 64-bit layout. Since debugging a 32-bit |
| 3813 | inferior with a 64-bit GDB should look the same as debugging it |
| 3814 | with a 32-bit GDB, we need to convert it. GDB core always sees |
| 3815 | the converted layout, so any read/write will have to be done |
| 3816 | post-conversion. */ |
| 3817 | siginfo_fixup (&siginfo, inf_siginfo, 0); |
| 3818 | |
| 3819 | if (offset + len > sizeof (siginfo)) |
| 3820 | len = sizeof (siginfo) - offset; |
| 3821 | |
| 3822 | if (readbuf != NULL) |
| 3823 | memcpy (readbuf, inf_siginfo + offset, len); |
| 3824 | else |
| 3825 | { |
| 3826 | memcpy (inf_siginfo + offset, writebuf, len); |
| 3827 | |
| 3828 | /* Convert back to ptrace layout before flushing it out. */ |
| 3829 | siginfo_fixup (&siginfo, inf_siginfo, 1); |
| 3830 | |
| 3831 | errno = 0; |
| 3832 | ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo); |
| 3833 | if (errno != 0) |
| 3834 | return TARGET_XFER_E_IO; |
| 3835 | } |
| 3836 | |
| 3837 | *xfered_len = len; |
| 3838 | return TARGET_XFER_OK; |
| 3839 | } |
| 3840 | |
| 3841 | static enum target_xfer_status |
| 3842 | linux_nat_xfer_osdata (enum target_object object, |
| 3843 | const char *annex, gdb_byte *readbuf, |
| 3844 | const gdb_byte *writebuf, ULONGEST offset, ULONGEST len, |
| 3845 | ULONGEST *xfered_len); |
| 3846 | |
| 3847 | static enum target_xfer_status |
| 3848 | linux_proc_xfer_spu (enum target_object object, |
| 3849 | const char *annex, gdb_byte *readbuf, |
| 3850 | const gdb_byte *writebuf, |
| 3851 | ULONGEST offset, ULONGEST len, ULONGEST *xfered_len); |
| 3852 | |
| 3853 | static enum target_xfer_status |
| 3854 | linux_proc_xfer_partial (enum target_object object, |
| 3855 | const char *annex, gdb_byte *readbuf, |
| 3856 | const gdb_byte *writebuf, |
| 3857 | ULONGEST offset, LONGEST len, ULONGEST *xfered_len); |
| 3858 | |
| 3859 | enum target_xfer_status |
| 3860 | linux_nat_target::xfer_partial (enum target_object object, |
| 3861 | const char *annex, gdb_byte *readbuf, |
| 3862 | const gdb_byte *writebuf, |
| 3863 | ULONGEST offset, ULONGEST len, ULONGEST *xfered_len) |
| 3864 | { |
| 3865 | enum target_xfer_status xfer; |
| 3866 | |
| 3867 | if (object == TARGET_OBJECT_SIGNAL_INFO) |
| 3868 | return linux_xfer_siginfo (object, annex, readbuf, writebuf, |
| 3869 | offset, len, xfered_len); |
| 3870 | |
| 3871 | /* The target is connected but no live inferior is selected. Pass |
| 3872 | this request down to a lower stratum (e.g., the executable |
| 3873 | file). */ |
| 3874 | if (object == TARGET_OBJECT_MEMORY && inferior_ptid == null_ptid) |
| 3875 | return TARGET_XFER_EOF; |
| 3876 | |
| 3877 | if (object == TARGET_OBJECT_AUXV) |
| 3878 | return memory_xfer_auxv (this, object, annex, readbuf, writebuf, |
| 3879 | offset, len, xfered_len); |
| 3880 | |
| 3881 | if (object == TARGET_OBJECT_OSDATA) |
| 3882 | return linux_nat_xfer_osdata (object, annex, readbuf, writebuf, |
| 3883 | offset, len, xfered_len); |
| 3884 | |
| 3885 | if (object == TARGET_OBJECT_SPU) |
| 3886 | return linux_proc_xfer_spu (object, annex, readbuf, writebuf, |
| 3887 | offset, len, xfered_len); |
| 3888 | |
| 3889 | /* GDB calculates all addresses in the largest possible address |
| 3890 | width. |
| 3891 | The address width must be masked before its final use - either by |
| 3892 | linux_proc_xfer_partial or inf_ptrace_target::xfer_partial. |
| 3893 | |
| 3894 | Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */ |
| 3895 | |
| 3896 | if (object == TARGET_OBJECT_MEMORY) |
| 3897 | { |
| 3898 | int addr_bit = gdbarch_addr_bit (target_gdbarch ()); |
| 3899 | |
| 3900 | if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT)) |
| 3901 | offset &= ((ULONGEST) 1 << addr_bit) - 1; |
| 3902 | } |
| 3903 | |
| 3904 | xfer = linux_proc_xfer_partial (object, annex, readbuf, writebuf, |
| 3905 | offset, len, xfered_len); |
| 3906 | if (xfer != TARGET_XFER_EOF) |
| 3907 | return xfer; |
| 3908 | |
| 3909 | return inf_ptrace_target::xfer_partial (object, annex, readbuf, writebuf, |
| 3910 | offset, len, xfered_len); |
| 3911 | } |
| 3912 | |
| 3913 | bool |
| 3914 | linux_nat_target::thread_alive (ptid_t ptid) |
| 3915 | { |
| 3916 | /* As long as a PTID is in lwp list, consider it alive. */ |
| 3917 | return find_lwp_pid (ptid) != NULL; |
| 3918 | } |
| 3919 | |
| 3920 | /* Implement the to_update_thread_list target method for this |
| 3921 | target. */ |
| 3922 | |
| 3923 | void |
| 3924 | linux_nat_target::update_thread_list () |
| 3925 | { |
| 3926 | struct lwp_info *lwp; |
| 3927 | |
| 3928 | /* We add/delete threads from the list as clone/exit events are |
| 3929 | processed, so just try deleting exited threads still in the |
| 3930 | thread list. */ |
| 3931 | delete_exited_threads (); |
| 3932 | |
| 3933 | /* Update the processor core that each lwp/thread was last seen |
| 3934 | running on. */ |
| 3935 | ALL_LWPS (lwp) |
| 3936 | { |
| 3937 | /* Avoid accessing /proc if the thread hasn't run since we last |
| 3938 | time we fetched the thread's core. Accessing /proc becomes |
| 3939 | noticeably expensive when we have thousands of LWPs. */ |
| 3940 | if (lwp->core == -1) |
| 3941 | lwp->core = linux_common_core_of_thread (lwp->ptid); |
| 3942 | } |
| 3943 | } |
| 3944 | |
| 3945 | std::string |
| 3946 | linux_nat_target::pid_to_str (ptid_t ptid) |
| 3947 | { |
| 3948 | if (ptid.lwp_p () |
| 3949 | && (ptid.pid () != ptid.lwp () |
| 3950 | || num_lwps (ptid.pid ()) > 1)) |
| 3951 | return string_printf ("LWP %ld", ptid.lwp ()); |
| 3952 | |
| 3953 | return normal_pid_to_str (ptid); |
| 3954 | } |
| 3955 | |
| 3956 | const char * |
| 3957 | linux_nat_target::thread_name (struct thread_info *thr) |
| 3958 | { |
| 3959 | return linux_proc_tid_get_name (thr->ptid); |
| 3960 | } |
| 3961 | |
| 3962 | /* Accepts an integer PID; Returns a string representing a file that |
| 3963 | can be opened to get the symbols for the child process. */ |
| 3964 | |
| 3965 | char * |
| 3966 | linux_nat_target::pid_to_exec_file (int pid) |
| 3967 | { |
| 3968 | return linux_proc_pid_to_exec_file (pid); |
| 3969 | } |
| 3970 | |
| 3971 | /* Implement the to_xfer_partial target method using /proc/<pid>/mem. |
| 3972 | Because we can use a single read/write call, this can be much more |
| 3973 | efficient than banging away at PTRACE_PEEKTEXT. */ |
| 3974 | |
| 3975 | static enum target_xfer_status |
| 3976 | linux_proc_xfer_partial (enum target_object object, |
| 3977 | const char *annex, gdb_byte *readbuf, |
| 3978 | const gdb_byte *writebuf, |
| 3979 | ULONGEST offset, LONGEST len, ULONGEST *xfered_len) |
| 3980 | { |
| 3981 | LONGEST ret; |
| 3982 | int fd; |
| 3983 | char filename[64]; |
| 3984 | |
| 3985 | if (object != TARGET_OBJECT_MEMORY) |
| 3986 | return TARGET_XFER_EOF; |
| 3987 | |
| 3988 | /* Don't bother for one word. */ |
| 3989 | if (len < 3 * sizeof (long)) |
| 3990 | return TARGET_XFER_EOF; |
| 3991 | |
| 3992 | /* We could keep this file open and cache it - possibly one per |
| 3993 | thread. That requires some juggling, but is even faster. */ |
| 3994 | xsnprintf (filename, sizeof filename, "/proc/%ld/mem", |
| 3995 | inferior_ptid.lwp ()); |
| 3996 | fd = gdb_open_cloexec (filename, ((readbuf ? O_RDONLY : O_WRONLY) |
| 3997 | | O_LARGEFILE), 0); |
| 3998 | if (fd == -1) |
| 3999 | return TARGET_XFER_EOF; |
| 4000 | |
| 4001 | /* Use pread64/pwrite64 if available, since they save a syscall and can |
| 4002 | handle 64-bit offsets even on 32-bit platforms (for instance, SPARC |
| 4003 | debugging a SPARC64 application). */ |
| 4004 | #ifdef HAVE_PREAD64 |
| 4005 | ret = (readbuf ? pread64 (fd, readbuf, len, offset) |
| 4006 | : pwrite64 (fd, writebuf, len, offset)); |
| 4007 | #else |
| 4008 | ret = lseek (fd, offset, SEEK_SET); |
| 4009 | if (ret != -1) |
| 4010 | ret = (readbuf ? read (fd, readbuf, len) |
| 4011 | : write (fd, writebuf, len)); |
| 4012 | #endif |
| 4013 | |
| 4014 | close (fd); |
| 4015 | |
| 4016 | if (ret == -1 || ret == 0) |
| 4017 | return TARGET_XFER_EOF; |
| 4018 | else |
| 4019 | { |
| 4020 | *xfered_len = ret; |
| 4021 | return TARGET_XFER_OK; |
| 4022 | } |
| 4023 | } |
| 4024 | |
| 4025 | |
| 4026 | /* Enumerate spufs IDs for process PID. */ |
| 4027 | static LONGEST |
| 4028 | spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len) |
| 4029 | { |
| 4030 | enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ()); |
| 4031 | LONGEST pos = 0; |
| 4032 | LONGEST written = 0; |
| 4033 | char path[128]; |
| 4034 | DIR *dir; |
| 4035 | struct dirent *entry; |
| 4036 | |
| 4037 | xsnprintf (path, sizeof path, "/proc/%d/fd", pid); |
| 4038 | dir = opendir (path); |
| 4039 | if (!dir) |
| 4040 | return -1; |
| 4041 | |
| 4042 | rewinddir (dir); |
| 4043 | while ((entry = readdir (dir)) != NULL) |
| 4044 | { |
| 4045 | struct stat st; |
| 4046 | struct statfs stfs; |
| 4047 | int fd; |
| 4048 | |
| 4049 | fd = atoi (entry->d_name); |
| 4050 | if (!fd) |
| 4051 | continue; |
| 4052 | |
| 4053 | xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd); |
| 4054 | if (stat (path, &st) != 0) |
| 4055 | continue; |
| 4056 | if (!S_ISDIR (st.st_mode)) |
| 4057 | continue; |
| 4058 | |
| 4059 | if (statfs (path, &stfs) != 0) |
| 4060 | continue; |
| 4061 | if (stfs.f_type != SPUFS_MAGIC) |
| 4062 | continue; |
| 4063 | |
| 4064 | if (pos >= offset && pos + 4 <= offset + len) |
| 4065 | { |
| 4066 | store_unsigned_integer (buf + pos - offset, 4, byte_order, fd); |
| 4067 | written += 4; |
| 4068 | } |
| 4069 | pos += 4; |
| 4070 | } |
| 4071 | |
| 4072 | closedir (dir); |
| 4073 | return written; |
| 4074 | } |
| 4075 | |
| 4076 | /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU |
| 4077 | object type, using the /proc file system. */ |
| 4078 | |
| 4079 | static enum target_xfer_status |
| 4080 | linux_proc_xfer_spu (enum target_object object, |
| 4081 | const char *annex, gdb_byte *readbuf, |
| 4082 | const gdb_byte *writebuf, |
| 4083 | ULONGEST offset, ULONGEST len, ULONGEST *xfered_len) |
| 4084 | { |
| 4085 | char buf[128]; |
| 4086 | int fd = 0; |
| 4087 | int ret = -1; |
| 4088 | int pid = inferior_ptid.lwp (); |
| 4089 | |
| 4090 | if (!annex) |
| 4091 | { |
| 4092 | if (!readbuf) |
| 4093 | return TARGET_XFER_E_IO; |
| 4094 | else |
| 4095 | { |
| 4096 | LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len); |
| 4097 | |
| 4098 | if (l < 0) |
| 4099 | return TARGET_XFER_E_IO; |
| 4100 | else if (l == 0) |
| 4101 | return TARGET_XFER_EOF; |
| 4102 | else |
| 4103 | { |
| 4104 | *xfered_len = (ULONGEST) l; |
| 4105 | return TARGET_XFER_OK; |
| 4106 | } |
| 4107 | } |
| 4108 | } |
| 4109 | |
| 4110 | xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex); |
| 4111 | fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0); |
| 4112 | if (fd <= 0) |
| 4113 | return TARGET_XFER_E_IO; |
| 4114 | |
| 4115 | if (offset != 0 |
| 4116 | && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset) |
| 4117 | { |
| 4118 | close (fd); |
| 4119 | return TARGET_XFER_EOF; |
| 4120 | } |
| 4121 | |
| 4122 | if (writebuf) |
| 4123 | ret = write (fd, writebuf, (size_t) len); |
| 4124 | else if (readbuf) |
| 4125 | ret = read (fd, readbuf, (size_t) len); |
| 4126 | |
| 4127 | close (fd); |
| 4128 | |
| 4129 | if (ret < 0) |
| 4130 | return TARGET_XFER_E_IO; |
| 4131 | else if (ret == 0) |
| 4132 | return TARGET_XFER_EOF; |
| 4133 | else |
| 4134 | { |
| 4135 | *xfered_len = (ULONGEST) ret; |
| 4136 | return TARGET_XFER_OK; |
| 4137 | } |
| 4138 | } |
| 4139 | |
| 4140 | |
| 4141 | /* Parse LINE as a signal set and add its set bits to SIGS. */ |
| 4142 | |
| 4143 | static void |
| 4144 | add_line_to_sigset (const char *line, sigset_t *sigs) |
| 4145 | { |
| 4146 | int len = strlen (line) - 1; |
| 4147 | const char *p; |
| 4148 | int signum; |
| 4149 | |
| 4150 | if (line[len] != '\n') |
| 4151 | error (_("Could not parse signal set: %s"), line); |
| 4152 | |
| 4153 | p = line; |
| 4154 | signum = len * 4; |
| 4155 | while (len-- > 0) |
| 4156 | { |
| 4157 | int digit; |
| 4158 | |
| 4159 | if (*p >= '0' && *p <= '9') |
| 4160 | digit = *p - '0'; |
| 4161 | else if (*p >= 'a' && *p <= 'f') |
| 4162 | digit = *p - 'a' + 10; |
| 4163 | else |
| 4164 | error (_("Could not parse signal set: %s"), line); |
| 4165 | |
| 4166 | signum -= 4; |
| 4167 | |
| 4168 | if (digit & 1) |
| 4169 | sigaddset (sigs, signum + 1); |
| 4170 | if (digit & 2) |
| 4171 | sigaddset (sigs, signum + 2); |
| 4172 | if (digit & 4) |
| 4173 | sigaddset (sigs, signum + 3); |
| 4174 | if (digit & 8) |
| 4175 | sigaddset (sigs, signum + 4); |
| 4176 | |
| 4177 | p++; |
| 4178 | } |
| 4179 | } |
| 4180 | |
| 4181 | /* Find process PID's pending signals from /proc/pid/status and set |
| 4182 | SIGS to match. */ |
| 4183 | |
| 4184 | void |
| 4185 | linux_proc_pending_signals (int pid, sigset_t *pending, |
| 4186 | sigset_t *blocked, sigset_t *ignored) |
| 4187 | { |
| 4188 | char buffer[PATH_MAX], fname[PATH_MAX]; |
| 4189 | |
| 4190 | sigemptyset (pending); |
| 4191 | sigemptyset (blocked); |
| 4192 | sigemptyset (ignored); |
| 4193 | xsnprintf (fname, sizeof fname, "/proc/%d/status", pid); |
| 4194 | gdb_file_up procfile = gdb_fopen_cloexec (fname, "r"); |
| 4195 | if (procfile == NULL) |
| 4196 | error (_("Could not open %s"), fname); |
| 4197 | |
| 4198 | while (fgets (buffer, PATH_MAX, procfile.get ()) != NULL) |
| 4199 | { |
| 4200 | /* Normal queued signals are on the SigPnd line in the status |
| 4201 | file. However, 2.6 kernels also have a "shared" pending |
| 4202 | queue for delivering signals to a thread group, so check for |
| 4203 | a ShdPnd line also. |
| 4204 | |
| 4205 | Unfortunately some Red Hat kernels include the shared pending |
| 4206 | queue but not the ShdPnd status field. */ |
| 4207 | |
| 4208 | if (startswith (buffer, "SigPnd:\t")) |
| 4209 | add_line_to_sigset (buffer + 8, pending); |
| 4210 | else if (startswith (buffer, "ShdPnd:\t")) |
| 4211 | add_line_to_sigset (buffer + 8, pending); |
| 4212 | else if (startswith (buffer, "SigBlk:\t")) |
| 4213 | add_line_to_sigset (buffer + 8, blocked); |
| 4214 | else if (startswith (buffer, "SigIgn:\t")) |
| 4215 | add_line_to_sigset (buffer + 8, ignored); |
| 4216 | } |
| 4217 | } |
| 4218 | |
| 4219 | static enum target_xfer_status |
| 4220 | linux_nat_xfer_osdata (enum target_object object, |
| 4221 | const char *annex, gdb_byte *readbuf, |
| 4222 | const gdb_byte *writebuf, ULONGEST offset, ULONGEST len, |
| 4223 | ULONGEST *xfered_len) |
| 4224 | { |
| 4225 | gdb_assert (object == TARGET_OBJECT_OSDATA); |
| 4226 | |
| 4227 | *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len); |
| 4228 | if (*xfered_len == 0) |
| 4229 | return TARGET_XFER_EOF; |
| 4230 | else |
| 4231 | return TARGET_XFER_OK; |
| 4232 | } |
| 4233 | |
| 4234 | std::vector<static_tracepoint_marker> |
| 4235 | linux_nat_target::static_tracepoint_markers_by_strid (const char *strid) |
| 4236 | { |
| 4237 | char s[IPA_CMD_BUF_SIZE]; |
| 4238 | int pid = inferior_ptid.pid (); |
| 4239 | std::vector<static_tracepoint_marker> markers; |
| 4240 | const char *p = s; |
| 4241 | ptid_t ptid = ptid_t (pid, 0, 0); |
| 4242 | static_tracepoint_marker marker; |
| 4243 | |
| 4244 | /* Pause all */ |
| 4245 | target_stop (ptid); |
| 4246 | |
| 4247 | memcpy (s, "qTfSTM", sizeof ("qTfSTM")); |
| 4248 | s[sizeof ("qTfSTM")] = 0; |
| 4249 | |
| 4250 | agent_run_command (pid, s, strlen (s) + 1); |
| 4251 | |
| 4252 | /* Unpause all. */ |
| 4253 | SCOPE_EXIT { target_continue_no_signal (ptid); }; |
| 4254 | |
| 4255 | while (*p++ == 'm') |
| 4256 | { |
| 4257 | do |
| 4258 | { |
| 4259 | parse_static_tracepoint_marker_definition (p, &p, &marker); |
| 4260 | |
| 4261 | if (strid == NULL || marker.str_id == strid) |
| 4262 | markers.push_back (std::move (marker)); |
| 4263 | } |
| 4264 | while (*p++ == ','); /* comma-separated list */ |
| 4265 | |
| 4266 | memcpy (s, "qTsSTM", sizeof ("qTsSTM")); |
| 4267 | s[sizeof ("qTsSTM")] = 0; |
| 4268 | agent_run_command (pid, s, strlen (s) + 1); |
| 4269 | p = s; |
| 4270 | } |
| 4271 | |
| 4272 | return markers; |
| 4273 | } |
| 4274 | |
| 4275 | /* target_is_async_p implementation. */ |
| 4276 | |
| 4277 | bool |
| 4278 | linux_nat_target::is_async_p () |
| 4279 | { |
| 4280 | return linux_is_async_p (); |
| 4281 | } |
| 4282 | |
| 4283 | /* target_can_async_p implementation. */ |
| 4284 | |
| 4285 | bool |
| 4286 | linux_nat_target::can_async_p () |
| 4287 | { |
| 4288 | /* We're always async, unless the user explicitly prevented it with the |
| 4289 | "maint set target-async" command. */ |
| 4290 | return target_async_permitted; |
| 4291 | } |
| 4292 | |
| 4293 | bool |
| 4294 | linux_nat_target::supports_non_stop () |
| 4295 | { |
| 4296 | return 1; |
| 4297 | } |
| 4298 | |
| 4299 | /* to_always_non_stop_p implementation. */ |
| 4300 | |
| 4301 | bool |
| 4302 | linux_nat_target::always_non_stop_p () |
| 4303 | { |
| 4304 | return 1; |
| 4305 | } |
| 4306 | |
| 4307 | /* True if we want to support multi-process. To be removed when GDB |
| 4308 | supports multi-exec. */ |
| 4309 | |
| 4310 | int linux_multi_process = 1; |
| 4311 | |
| 4312 | bool |
| 4313 | linux_nat_target::supports_multi_process () |
| 4314 | { |
| 4315 | return linux_multi_process; |
| 4316 | } |
| 4317 | |
| 4318 | bool |
| 4319 | linux_nat_target::supports_disable_randomization () |
| 4320 | { |
| 4321 | #ifdef HAVE_PERSONALITY |
| 4322 | return 1; |
| 4323 | #else |
| 4324 | return 0; |
| 4325 | #endif |
| 4326 | } |
| 4327 | |
| 4328 | /* SIGCHLD handler that serves two purposes: In non-stop/async mode, |
| 4329 | so we notice when any child changes state, and notify the |
| 4330 | event-loop; it allows us to use sigsuspend in linux_nat_wait_1 |
| 4331 | above to wait for the arrival of a SIGCHLD. */ |
| 4332 | |
| 4333 | static void |
| 4334 | sigchld_handler (int signo) |
| 4335 | { |
| 4336 | int old_errno = errno; |
| 4337 | |
| 4338 | if (debug_linux_nat) |
| 4339 | ui_file_write_async_safe (gdb_stdlog, |
| 4340 | "sigchld\n", sizeof ("sigchld\n") - 1); |
| 4341 | |
| 4342 | if (signo == SIGCHLD |
| 4343 | && linux_nat_event_pipe[0] != -1) |
| 4344 | async_file_mark (); /* Let the event loop know that there are |
| 4345 | events to handle. */ |
| 4346 | |
| 4347 | errno = old_errno; |
| 4348 | } |
| 4349 | |
| 4350 | /* Callback registered with the target events file descriptor. */ |
| 4351 | |
| 4352 | static void |
| 4353 | handle_target_event (int error, gdb_client_data client_data) |
| 4354 | { |
| 4355 | inferior_event_handler (INF_REG_EVENT, NULL); |
| 4356 | } |
| 4357 | |
| 4358 | /* Create/destroy the target events pipe. Returns previous state. */ |
| 4359 | |
| 4360 | static int |
| 4361 | linux_async_pipe (int enable) |
| 4362 | { |
| 4363 | int previous = linux_is_async_p (); |
| 4364 | |
| 4365 | if (previous != enable) |
| 4366 | { |
| 4367 | sigset_t prev_mask; |
| 4368 | |
| 4369 | /* Block child signals while we create/destroy the pipe, as |
| 4370 | their handler writes to it. */ |
| 4371 | block_child_signals (&prev_mask); |
| 4372 | |
| 4373 | if (enable) |
| 4374 | { |
| 4375 | if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1) |
| 4376 | internal_error (__FILE__, __LINE__, |
| 4377 | "creating event pipe failed."); |
| 4378 | |
| 4379 | fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK); |
| 4380 | fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK); |
| 4381 | } |
| 4382 | else |
| 4383 | { |
| 4384 | close (linux_nat_event_pipe[0]); |
| 4385 | close (linux_nat_event_pipe[1]); |
| 4386 | linux_nat_event_pipe[0] = -1; |
| 4387 | linux_nat_event_pipe[1] = -1; |
| 4388 | } |
| 4389 | |
| 4390 | restore_child_signals_mask (&prev_mask); |
| 4391 | } |
| 4392 | |
| 4393 | return previous; |
| 4394 | } |
| 4395 | |
| 4396 | /* target_async implementation. */ |
| 4397 | |
| 4398 | void |
| 4399 | linux_nat_target::async (int enable) |
| 4400 | { |
| 4401 | if (enable) |
| 4402 | { |
| 4403 | if (!linux_async_pipe (1)) |
| 4404 | { |
| 4405 | add_file_handler (linux_nat_event_pipe[0], |
| 4406 | handle_target_event, NULL); |
| 4407 | /* There may be pending events to handle. Tell the event loop |
| 4408 | to poll them. */ |
| 4409 | async_file_mark (); |
| 4410 | } |
| 4411 | } |
| 4412 | else |
| 4413 | { |
| 4414 | delete_file_handler (linux_nat_event_pipe[0]); |
| 4415 | linux_async_pipe (0); |
| 4416 | } |
| 4417 | return; |
| 4418 | } |
| 4419 | |
| 4420 | /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other |
| 4421 | event came out. */ |
| 4422 | |
| 4423 | static int |
| 4424 | linux_nat_stop_lwp (struct lwp_info *lwp) |
| 4425 | { |
| 4426 | if (!lwp->stopped) |
| 4427 | { |
| 4428 | if (debug_linux_nat) |
| 4429 | fprintf_unfiltered (gdb_stdlog, |
| 4430 | "LNSL: running -> suspending %s\n", |
| 4431 | target_pid_to_str (lwp->ptid).c_str ()); |
| 4432 | |
| 4433 | |
| 4434 | if (lwp->last_resume_kind == resume_stop) |
| 4435 | { |
| 4436 | if (debug_linux_nat) |
| 4437 | fprintf_unfiltered (gdb_stdlog, |
| 4438 | "linux-nat: already stopping LWP %ld at " |
| 4439 | "GDB's request\n", |
| 4440 | lwp->ptid.lwp ()); |
| 4441 | return 0; |
| 4442 | } |
| 4443 | |
| 4444 | stop_callback (lwp); |
| 4445 | lwp->last_resume_kind = resume_stop; |
| 4446 | } |
| 4447 | else |
| 4448 | { |
| 4449 | /* Already known to be stopped; do nothing. */ |
| 4450 | |
| 4451 | if (debug_linux_nat) |
| 4452 | { |
| 4453 | if (find_thread_ptid (lwp->ptid)->stop_requested) |
| 4454 | fprintf_unfiltered (gdb_stdlog, |
| 4455 | "LNSL: already stopped/stop_requested %s\n", |
| 4456 | target_pid_to_str (lwp->ptid).c_str ()); |
| 4457 | else |
| 4458 | fprintf_unfiltered (gdb_stdlog, |
| 4459 | "LNSL: already stopped/no " |
| 4460 | "stop_requested yet %s\n", |
| 4461 | target_pid_to_str (lwp->ptid).c_str ()); |
| 4462 | } |
| 4463 | } |
| 4464 | return 0; |
| 4465 | } |
| 4466 | |
| 4467 | void |
| 4468 | linux_nat_target::stop (ptid_t ptid) |
| 4469 | { |
| 4470 | iterate_over_lwps (ptid, linux_nat_stop_lwp); |
| 4471 | } |
| 4472 | |
| 4473 | void |
| 4474 | linux_nat_target::close () |
| 4475 | { |
| 4476 | /* Unregister from the event loop. */ |
| 4477 | if (is_async_p ()) |
| 4478 | async (0); |
| 4479 | |
| 4480 | inf_ptrace_target::close (); |
| 4481 | } |
| 4482 | |
| 4483 | /* When requests are passed down from the linux-nat layer to the |
| 4484 | single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are |
| 4485 | used. The address space pointer is stored in the inferior object, |
| 4486 | but the common code that is passed such ptid can't tell whether |
| 4487 | lwpid is a "main" process id or not (it assumes so). We reverse |
| 4488 | look up the "main" process id from the lwp here. */ |
| 4489 | |
| 4490 | struct address_space * |
| 4491 | linux_nat_target::thread_address_space (ptid_t ptid) |
| 4492 | { |
| 4493 | struct lwp_info *lwp; |
| 4494 | struct inferior *inf; |
| 4495 | int pid; |
| 4496 | |
| 4497 | if (ptid.lwp () == 0) |
| 4498 | { |
| 4499 | /* An (lwpid,0,0) ptid. Look up the lwp object to get at the |
| 4500 | tgid. */ |
| 4501 | lwp = find_lwp_pid (ptid); |
| 4502 | pid = lwp->ptid.pid (); |
| 4503 | } |
| 4504 | else |
| 4505 | { |
| 4506 | /* A (pid,lwpid,0) ptid. */ |
| 4507 | pid = ptid.pid (); |
| 4508 | } |
| 4509 | |
| 4510 | inf = find_inferior_pid (pid); |
| 4511 | gdb_assert (inf != NULL); |
| 4512 | return inf->aspace; |
| 4513 | } |
| 4514 | |
| 4515 | /* Return the cached value of the processor core for thread PTID. */ |
| 4516 | |
| 4517 | int |
| 4518 | linux_nat_target::core_of_thread (ptid_t ptid) |
| 4519 | { |
| 4520 | struct lwp_info *info = find_lwp_pid (ptid); |
| 4521 | |
| 4522 | if (info) |
| 4523 | return info->core; |
| 4524 | return -1; |
| 4525 | } |
| 4526 | |
| 4527 | /* Implementation of to_filesystem_is_local. */ |
| 4528 | |
| 4529 | bool |
| 4530 | linux_nat_target::filesystem_is_local () |
| 4531 | { |
| 4532 | struct inferior *inf = current_inferior (); |
| 4533 | |
| 4534 | if (inf->fake_pid_p || inf->pid == 0) |
| 4535 | return true; |
| 4536 | |
| 4537 | return linux_ns_same (inf->pid, LINUX_NS_MNT); |
| 4538 | } |
| 4539 | |
| 4540 | /* Convert the INF argument passed to a to_fileio_* method |
| 4541 | to a process ID suitable for passing to its corresponding |
| 4542 | linux_mntns_* function. If INF is non-NULL then the |
| 4543 | caller is requesting the filesystem seen by INF. If INF |
| 4544 | is NULL then the caller is requesting the filesystem seen |
| 4545 | by the GDB. We fall back to GDB's filesystem in the case |
| 4546 | that INF is non-NULL but its PID is unknown. */ |
| 4547 | |
| 4548 | static pid_t |
| 4549 | linux_nat_fileio_pid_of (struct inferior *inf) |
| 4550 | { |
| 4551 | if (inf == NULL || inf->fake_pid_p || inf->pid == 0) |
| 4552 | return getpid (); |
| 4553 | else |
| 4554 | return inf->pid; |
| 4555 | } |
| 4556 | |
| 4557 | /* Implementation of to_fileio_open. */ |
| 4558 | |
| 4559 | int |
| 4560 | linux_nat_target::fileio_open (struct inferior *inf, const char *filename, |
| 4561 | int flags, int mode, int warn_if_slow, |
| 4562 | int *target_errno) |
| 4563 | { |
| 4564 | int nat_flags; |
| 4565 | mode_t nat_mode; |
| 4566 | int fd; |
| 4567 | |
| 4568 | if (fileio_to_host_openflags (flags, &nat_flags) == -1 |
| 4569 | || fileio_to_host_mode (mode, &nat_mode) == -1) |
| 4570 | { |
| 4571 | *target_errno = FILEIO_EINVAL; |
| 4572 | return -1; |
| 4573 | } |
| 4574 | |
| 4575 | fd = linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf), |
| 4576 | filename, nat_flags, nat_mode); |
| 4577 | if (fd == -1) |
| 4578 | *target_errno = host_to_fileio_error (errno); |
| 4579 | |
| 4580 | return fd; |
| 4581 | } |
| 4582 | |
| 4583 | /* Implementation of to_fileio_readlink. */ |
| 4584 | |
| 4585 | gdb::optional<std::string> |
| 4586 | linux_nat_target::fileio_readlink (struct inferior *inf, const char *filename, |
| 4587 | int *target_errno) |
| 4588 | { |
| 4589 | char buf[PATH_MAX]; |
| 4590 | int len; |
| 4591 | |
| 4592 | len = linux_mntns_readlink (linux_nat_fileio_pid_of (inf), |
| 4593 | filename, buf, sizeof (buf)); |
| 4594 | if (len < 0) |
| 4595 | { |
| 4596 | *target_errno = host_to_fileio_error (errno); |
| 4597 | return {}; |
| 4598 | } |
| 4599 | |
| 4600 | return std::string (buf, len); |
| 4601 | } |
| 4602 | |
| 4603 | /* Implementation of to_fileio_unlink. */ |
| 4604 | |
| 4605 | int |
| 4606 | linux_nat_target::fileio_unlink (struct inferior *inf, const char *filename, |
| 4607 | int *target_errno) |
| 4608 | { |
| 4609 | int ret; |
| 4610 | |
| 4611 | ret = linux_mntns_unlink (linux_nat_fileio_pid_of (inf), |
| 4612 | filename); |
| 4613 | if (ret == -1) |
| 4614 | *target_errno = host_to_fileio_error (errno); |
| 4615 | |
| 4616 | return ret; |
| 4617 | } |
| 4618 | |
| 4619 | /* Implementation of the to_thread_events method. */ |
| 4620 | |
| 4621 | void |
| 4622 | linux_nat_target::thread_events (int enable) |
| 4623 | { |
| 4624 | report_thread_events = enable; |
| 4625 | } |
| 4626 | |
| 4627 | linux_nat_target::linux_nat_target () |
| 4628 | { |
| 4629 | /* We don't change the stratum; this target will sit at |
| 4630 | process_stratum and thread_db will set at thread_stratum. This |
| 4631 | is a little strange, since this is a multi-threaded-capable |
| 4632 | target, but we want to be on the stack below thread_db, and we |
| 4633 | also want to be used for single-threaded processes. */ |
| 4634 | } |
| 4635 | |
| 4636 | /* See linux-nat.h. */ |
| 4637 | |
| 4638 | int |
| 4639 | linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo) |
| 4640 | { |
| 4641 | int pid; |
| 4642 | |
| 4643 | pid = ptid.lwp (); |
| 4644 | if (pid == 0) |
| 4645 | pid = ptid.pid (); |
| 4646 | |
| 4647 | errno = 0; |
| 4648 | ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo); |
| 4649 | if (errno != 0) |
| 4650 | { |
| 4651 | memset (siginfo, 0, sizeof (*siginfo)); |
| 4652 | return 0; |
| 4653 | } |
| 4654 | return 1; |
| 4655 | } |
| 4656 | |
| 4657 | /* See nat/linux-nat.h. */ |
| 4658 | |
| 4659 | ptid_t |
| 4660 | current_lwp_ptid (void) |
| 4661 | { |
| 4662 | gdb_assert (inferior_ptid.lwp_p ()); |
| 4663 | return inferior_ptid; |
| 4664 | } |
| 4665 | |
| 4666 | void |
| 4667 | _initialize_linux_nat (void) |
| 4668 | { |
| 4669 | add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance, |
| 4670 | &debug_linux_nat, _("\ |
| 4671 | Set debugging of GNU/Linux lwp module."), _("\ |
| 4672 | Show debugging of GNU/Linux lwp module."), _("\ |
| 4673 | Enables printf debugging output."), |
| 4674 | NULL, |
| 4675 | show_debug_linux_nat, |
| 4676 | &setdebuglist, &showdebuglist); |
| 4677 | |
| 4678 | add_setshow_boolean_cmd ("linux-namespaces", class_maintenance, |
| 4679 | &debug_linux_namespaces, _("\ |
| 4680 | Set debugging of GNU/Linux namespaces module."), _("\ |
| 4681 | Show debugging of GNU/Linux namespaces module."), _("\ |
| 4682 | Enables printf debugging output."), |
| 4683 | NULL, |
| 4684 | NULL, |
| 4685 | &setdebuglist, &showdebuglist); |
| 4686 | |
| 4687 | /* Save this mask as the default. */ |
| 4688 | sigprocmask (SIG_SETMASK, NULL, &normal_mask); |
| 4689 | |
| 4690 | /* Install a SIGCHLD handler. */ |
| 4691 | sigchld_action.sa_handler = sigchld_handler; |
| 4692 | sigemptyset (&sigchld_action.sa_mask); |
| 4693 | sigchld_action.sa_flags = SA_RESTART; |
| 4694 | |
| 4695 | /* Make it the default. */ |
| 4696 | sigaction (SIGCHLD, &sigchld_action, NULL); |
| 4697 | |
| 4698 | /* Make sure we don't block SIGCHLD during a sigsuspend. */ |
| 4699 | sigprocmask (SIG_SETMASK, NULL, &suspend_mask); |
| 4700 | sigdelset (&suspend_mask, SIGCHLD); |
| 4701 | |
| 4702 | sigemptyset (&blocked_mask); |
| 4703 | |
| 4704 | lwp_lwpid_htab_create (); |
| 4705 | } |
| 4706 | \f |
| 4707 | |
| 4708 | /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to |
| 4709 | the GNU/Linux Threads library and therefore doesn't really belong |
| 4710 | here. */ |
| 4711 | |
| 4712 | /* Return the set of signals used by the threads library in *SET. */ |
| 4713 | |
| 4714 | void |
| 4715 | lin_thread_get_thread_signals (sigset_t *set) |
| 4716 | { |
| 4717 | sigemptyset (set); |
| 4718 | |
| 4719 | /* NPTL reserves the first two RT signals, but does not provide any |
| 4720 | way for the debugger to query the signal numbers - fortunately |
| 4721 | they don't change. */ |
| 4722 | sigaddset (set, __SIGRTMIN); |
| 4723 | sigaddset (set, __SIGRTMIN + 1); |
| 4724 | } |