| 1 | /* libthread_db assisted debugging support, generic parts. |
| 2 | |
| 3 | Copyright (C) 1999-2015 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 <dlfcn.h> |
| 22 | #include "gdb_proc_service.h" |
| 23 | #include "nat/gdb_thread_db.h" |
| 24 | #include "gdb_vecs.h" |
| 25 | #include "bfd.h" |
| 26 | #include "command.h" |
| 27 | #include "gdbcmd.h" |
| 28 | #include "gdbthread.h" |
| 29 | #include "inferior.h" |
| 30 | #include "infrun.h" |
| 31 | #include "symfile.h" |
| 32 | #include "objfiles.h" |
| 33 | #include "target.h" |
| 34 | #include "regcache.h" |
| 35 | #include "solib.h" |
| 36 | #include "solib-svr4.h" |
| 37 | #include "gdbcore.h" |
| 38 | #include "observer.h" |
| 39 | #include "linux-nat.h" |
| 40 | #include "nat/linux-procfs.h" |
| 41 | #include "nat/linux-ptrace.h" |
| 42 | #include "nat/linux-osdata.h" |
| 43 | #include "auto-load.h" |
| 44 | #include "cli/cli-utils.h" |
| 45 | #include <signal.h> |
| 46 | #include <ctype.h> |
| 47 | #include "nat/linux-namespaces.h" |
| 48 | |
| 49 | /* GNU/Linux libthread_db support. |
| 50 | |
| 51 | libthread_db is a library, provided along with libpthread.so, which |
| 52 | exposes the internals of the thread library to a debugger. It |
| 53 | allows GDB to find existing threads, new threads as they are |
| 54 | created, thread IDs (usually, the result of pthread_self), and |
| 55 | thread-local variables. |
| 56 | |
| 57 | The libthread_db interface originates on Solaris, where it is |
| 58 | both more powerful and more complicated. This implementation |
| 59 | only works for LinuxThreads and NPTL, the two glibc threading |
| 60 | libraries. It assumes that each thread is permanently assigned |
| 61 | to a single light-weight process (LWP). |
| 62 | |
| 63 | libthread_db-specific information is stored in the "private" field |
| 64 | of struct thread_info. When the field is NULL we do not yet have |
| 65 | information about the new thread; this could be temporary (created, |
| 66 | but the thread library's data structures do not reflect it yet) |
| 67 | or permanent (created using clone instead of pthread_create). |
| 68 | |
| 69 | Process IDs managed by linux-thread-db.c match those used by |
| 70 | linux-nat.c: a common PID for all processes, an LWP ID for each |
| 71 | thread, and no TID. We save the TID in private. Keeping it out |
| 72 | of the ptid_t prevents thread IDs changing when libpthread is |
| 73 | loaded or unloaded. */ |
| 74 | |
| 75 | static char *libthread_db_search_path; |
| 76 | |
| 77 | /* Set to non-zero if thread_db auto-loading is enabled |
| 78 | by the "set auto-load libthread-db" command. */ |
| 79 | static int auto_load_thread_db = 1; |
| 80 | |
| 81 | /* Returns true if we need to use thread_db thread create/death event |
| 82 | breakpoints to learn about threads. */ |
| 83 | |
| 84 | static int |
| 85 | thread_db_use_events (void) |
| 86 | { |
| 87 | /* Not necessary if the kernel supports clone events. */ |
| 88 | return !linux_supports_traceclone (); |
| 89 | } |
| 90 | |
| 91 | /* "show" command for the auto_load_thread_db configuration variable. */ |
| 92 | |
| 93 | static void |
| 94 | show_auto_load_thread_db (struct ui_file *file, int from_tty, |
| 95 | struct cmd_list_element *c, const char *value) |
| 96 | { |
| 97 | fprintf_filtered (file, _("Auto-loading of inferior specific libthread_db " |
| 98 | "is %s.\n"), |
| 99 | value); |
| 100 | } |
| 101 | |
| 102 | static void |
| 103 | set_libthread_db_search_path (char *ignored, int from_tty, |
| 104 | struct cmd_list_element *c) |
| 105 | { |
| 106 | if (*libthread_db_search_path == '\0') |
| 107 | { |
| 108 | xfree (libthread_db_search_path); |
| 109 | libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH); |
| 110 | } |
| 111 | } |
| 112 | |
| 113 | /* If non-zero, print details of libthread_db processing. */ |
| 114 | |
| 115 | static unsigned int libthread_db_debug; |
| 116 | |
| 117 | static void |
| 118 | show_libthread_db_debug (struct ui_file *file, int from_tty, |
| 119 | struct cmd_list_element *c, const char *value) |
| 120 | { |
| 121 | fprintf_filtered (file, _("libthread-db debugging is %s.\n"), value); |
| 122 | } |
| 123 | |
| 124 | /* If we're running on GNU/Linux, we must explicitly attach to any new |
| 125 | threads. */ |
| 126 | |
| 127 | /* This module's target vector. */ |
| 128 | static struct target_ops thread_db_ops; |
| 129 | |
| 130 | /* Non-zero if we have determined the signals used by the threads |
| 131 | library. */ |
| 132 | static int thread_signals; |
| 133 | static sigset_t thread_stop_set; |
| 134 | static sigset_t thread_print_set; |
| 135 | |
| 136 | struct thread_db_info |
| 137 | { |
| 138 | struct thread_db_info *next; |
| 139 | |
| 140 | /* Process id this object refers to. */ |
| 141 | int pid; |
| 142 | |
| 143 | /* Handle from dlopen for libthread_db.so. */ |
| 144 | void *handle; |
| 145 | |
| 146 | /* Absolute pathname from gdb_realpath to disk file used for dlopen-ing |
| 147 | HANDLE. It may be NULL for system library. */ |
| 148 | char *filename; |
| 149 | |
| 150 | /* Structure that identifies the child process for the |
| 151 | <proc_service.h> interface. */ |
| 152 | struct ps_prochandle proc_handle; |
| 153 | |
| 154 | /* Connection to the libthread_db library. */ |
| 155 | td_thragent_t *thread_agent; |
| 156 | |
| 157 | /* True if we need to apply the workaround for glibc/BZ5983. When |
| 158 | we catch a PTRACE_O_TRACEFORK, and go query the child's thread |
| 159 | list, nptl_db returns the parent's threads in addition to the new |
| 160 | (single) child thread. If this flag is set, we do extra work to |
| 161 | be able to ignore such stale entries. */ |
| 162 | int need_stale_parent_threads_check; |
| 163 | |
| 164 | /* Location of the thread creation event breakpoint. The code at |
| 165 | this location in the child process will be called by the pthread |
| 166 | library whenever a new thread is created. By setting a special |
| 167 | breakpoint at this location, GDB can detect when a new thread is |
| 168 | created. We obtain this location via the td_ta_event_addr |
| 169 | call. */ |
| 170 | CORE_ADDR td_create_bp_addr; |
| 171 | |
| 172 | /* Location of the thread death event breakpoint. */ |
| 173 | CORE_ADDR td_death_bp_addr; |
| 174 | |
| 175 | /* Pointers to the libthread_db functions. */ |
| 176 | |
| 177 | td_init_ftype *td_init_p; |
| 178 | td_ta_new_ftype *td_ta_new_p; |
| 179 | td_ta_map_lwp2thr_ftype *td_ta_map_lwp2thr_p; |
| 180 | td_ta_thr_iter_ftype *td_ta_thr_iter_p; |
| 181 | td_ta_event_addr_ftype *td_ta_event_addr_p; |
| 182 | td_ta_set_event_ftype *td_ta_set_event_p; |
| 183 | td_ta_clear_event_ftype *td_ta_clear_event_p; |
| 184 | td_ta_event_getmsg_ftype * td_ta_event_getmsg_p; |
| 185 | td_thr_validate_ftype *td_thr_validate_p; |
| 186 | td_thr_get_info_ftype *td_thr_get_info_p; |
| 187 | td_thr_event_enable_ftype *td_thr_event_enable_p; |
| 188 | td_thr_tls_get_addr_ftype *td_thr_tls_get_addr_p; |
| 189 | td_thr_tlsbase_ftype *td_thr_tlsbase_p; |
| 190 | }; |
| 191 | |
| 192 | /* List of known processes using thread_db, and the required |
| 193 | bookkeeping. */ |
| 194 | struct thread_db_info *thread_db_list; |
| 195 | |
| 196 | static void thread_db_find_new_threads_1 (ptid_t ptid); |
| 197 | static void thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new); |
| 198 | |
| 199 | static void check_thread_signals (void); |
| 200 | |
| 201 | static void record_thread (struct thread_db_info *info, |
| 202 | struct thread_info *tp, |
| 203 | ptid_t ptid, const td_thrhandle_t *th_p, |
| 204 | const td_thrinfo_t *ti_p); |
| 205 | |
| 206 | /* Add the current inferior to the list of processes using libpthread. |
| 207 | Return a pointer to the newly allocated object that was added to |
| 208 | THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing |
| 209 | LIBTHREAD_DB_SO. */ |
| 210 | |
| 211 | static struct thread_db_info * |
| 212 | add_thread_db_info (void *handle) |
| 213 | { |
| 214 | struct thread_db_info *info = XCNEW (struct thread_db_info); |
| 215 | |
| 216 | info->pid = ptid_get_pid (inferior_ptid); |
| 217 | info->handle = handle; |
| 218 | |
| 219 | /* The workaround works by reading from /proc/pid/status, so it is |
| 220 | disabled for core files. */ |
| 221 | if (target_has_execution) |
| 222 | info->need_stale_parent_threads_check = 1; |
| 223 | |
| 224 | info->next = thread_db_list; |
| 225 | thread_db_list = info; |
| 226 | |
| 227 | return info; |
| 228 | } |
| 229 | |
| 230 | /* Return the thread_db_info object representing the bookkeeping |
| 231 | related to process PID, if any; NULL otherwise. */ |
| 232 | |
| 233 | static struct thread_db_info * |
| 234 | get_thread_db_info (int pid) |
| 235 | { |
| 236 | struct thread_db_info *info; |
| 237 | |
| 238 | for (info = thread_db_list; info; info = info->next) |
| 239 | if (pid == info->pid) |
| 240 | return info; |
| 241 | |
| 242 | return NULL; |
| 243 | } |
| 244 | |
| 245 | /* When PID has exited or has been detached, we no longer want to keep |
| 246 | track of it as using libpthread. Call this function to discard |
| 247 | thread_db related info related to PID. Note that this closes |
| 248 | LIBTHREAD_DB_SO's dlopen'ed handle. */ |
| 249 | |
| 250 | static void |
| 251 | delete_thread_db_info (int pid) |
| 252 | { |
| 253 | struct thread_db_info *info, *info_prev; |
| 254 | |
| 255 | info_prev = NULL; |
| 256 | |
| 257 | for (info = thread_db_list; info; info_prev = info, info = info->next) |
| 258 | if (pid == info->pid) |
| 259 | break; |
| 260 | |
| 261 | if (info == NULL) |
| 262 | return; |
| 263 | |
| 264 | if (info->handle != NULL) |
| 265 | dlclose (info->handle); |
| 266 | |
| 267 | xfree (info->filename); |
| 268 | |
| 269 | if (info_prev) |
| 270 | info_prev->next = info->next; |
| 271 | else |
| 272 | thread_db_list = info->next; |
| 273 | |
| 274 | xfree (info); |
| 275 | } |
| 276 | |
| 277 | /* Prototypes for local functions. */ |
| 278 | static int attach_thread (ptid_t ptid, const td_thrhandle_t *th_p, |
| 279 | const td_thrinfo_t *ti_p); |
| 280 | static void detach_thread (ptid_t ptid); |
| 281 | \f |
| 282 | |
| 283 | /* Use "struct private_thread_info" to cache thread state. This is |
| 284 | a substantial optimization. */ |
| 285 | |
| 286 | struct private_thread_info |
| 287 | { |
| 288 | /* Flag set when we see a TD_DEATH event for this thread. */ |
| 289 | unsigned int dying:1; |
| 290 | |
| 291 | /* Cached thread state. */ |
| 292 | td_thrhandle_t th; |
| 293 | thread_t tid; |
| 294 | }; |
| 295 | \f |
| 296 | |
| 297 | static char * |
| 298 | thread_db_err_str (td_err_e err) |
| 299 | { |
| 300 | static char buf[64]; |
| 301 | |
| 302 | switch (err) |
| 303 | { |
| 304 | case TD_OK: |
| 305 | return "generic 'call succeeded'"; |
| 306 | case TD_ERR: |
| 307 | return "generic error"; |
| 308 | case TD_NOTHR: |
| 309 | return "no thread to satisfy query"; |
| 310 | case TD_NOSV: |
| 311 | return "no sync handle to satisfy query"; |
| 312 | case TD_NOLWP: |
| 313 | return "no LWP to satisfy query"; |
| 314 | case TD_BADPH: |
| 315 | return "invalid process handle"; |
| 316 | case TD_BADTH: |
| 317 | return "invalid thread handle"; |
| 318 | case TD_BADSH: |
| 319 | return "invalid synchronization handle"; |
| 320 | case TD_BADTA: |
| 321 | return "invalid thread agent"; |
| 322 | case TD_BADKEY: |
| 323 | return "invalid key"; |
| 324 | case TD_NOMSG: |
| 325 | return "no event message for getmsg"; |
| 326 | case TD_NOFPREGS: |
| 327 | return "FPU register set not available"; |
| 328 | case TD_NOLIBTHREAD: |
| 329 | return "application not linked with libthread"; |
| 330 | case TD_NOEVENT: |
| 331 | return "requested event is not supported"; |
| 332 | case TD_NOCAPAB: |
| 333 | return "capability not available"; |
| 334 | case TD_DBERR: |
| 335 | return "debugger service failed"; |
| 336 | case TD_NOAPLIC: |
| 337 | return "operation not applicable to"; |
| 338 | case TD_NOTSD: |
| 339 | return "no thread-specific data for this thread"; |
| 340 | case TD_MALLOC: |
| 341 | return "malloc failed"; |
| 342 | case TD_PARTIALREG: |
| 343 | return "only part of register set was written/read"; |
| 344 | case TD_NOXREGS: |
| 345 | return "X register set not available for this thread"; |
| 346 | #ifdef THREAD_DB_HAS_TD_NOTALLOC |
| 347 | case TD_NOTALLOC: |
| 348 | return "thread has not yet allocated TLS for given module"; |
| 349 | #endif |
| 350 | #ifdef THREAD_DB_HAS_TD_VERSION |
| 351 | case TD_VERSION: |
| 352 | return "versions of libpthread and libthread_db do not match"; |
| 353 | #endif |
| 354 | #ifdef THREAD_DB_HAS_TD_NOTLS |
| 355 | case TD_NOTLS: |
| 356 | return "there is no TLS segment in the given module"; |
| 357 | #endif |
| 358 | default: |
| 359 | snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err); |
| 360 | return buf; |
| 361 | } |
| 362 | } |
| 363 | \f |
| 364 | /* Return 1 if any threads have been registered. There may be none if |
| 365 | the threading library is not fully initialized yet. */ |
| 366 | |
| 367 | static int |
| 368 | have_threads_callback (struct thread_info *thread, void *args) |
| 369 | { |
| 370 | int pid = * (int *) args; |
| 371 | |
| 372 | if (ptid_get_pid (thread->ptid) != pid) |
| 373 | return 0; |
| 374 | |
| 375 | return thread->priv != NULL; |
| 376 | } |
| 377 | |
| 378 | static int |
| 379 | have_threads (ptid_t ptid) |
| 380 | { |
| 381 | int pid = ptid_get_pid (ptid); |
| 382 | |
| 383 | return iterate_over_threads (have_threads_callback, &pid) != NULL; |
| 384 | } |
| 385 | |
| 386 | \f |
| 387 | /* Fetch the user-level thread id of PTID. */ |
| 388 | |
| 389 | static void |
| 390 | thread_from_lwp (ptid_t ptid) |
| 391 | { |
| 392 | td_thrhandle_t th; |
| 393 | td_thrinfo_t ti; |
| 394 | td_err_e err; |
| 395 | struct thread_db_info *info; |
| 396 | struct thread_info *tp; |
| 397 | |
| 398 | /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */ |
| 399 | th.th_unique = 0; |
| 400 | |
| 401 | /* This ptid comes from linux-nat.c, which should always fill in the |
| 402 | LWP. */ |
| 403 | gdb_assert (ptid_get_lwp (ptid) != 0); |
| 404 | |
| 405 | info = get_thread_db_info (ptid_get_pid (ptid)); |
| 406 | |
| 407 | /* Access an lwp we know is stopped. */ |
| 408 | info->proc_handle.ptid = ptid; |
| 409 | err = info->td_ta_map_lwp2thr_p (info->thread_agent, ptid_get_lwp (ptid), |
| 410 | &th); |
| 411 | if (err != TD_OK) |
| 412 | error (_("Cannot find user-level thread for LWP %ld: %s"), |
| 413 | ptid_get_lwp (ptid), thread_db_err_str (err)); |
| 414 | |
| 415 | err = info->td_thr_get_info_p (&th, &ti); |
| 416 | if (err != TD_OK) |
| 417 | error (_("thread_get_info_callback: cannot get thread info: %s"), |
| 418 | thread_db_err_str (err)); |
| 419 | |
| 420 | /* Fill the cache. */ |
| 421 | tp = find_thread_ptid (ptid); |
| 422 | record_thread (info, tp, ptid, &th, &ti); |
| 423 | } |
| 424 | \f |
| 425 | |
| 426 | /* See linux-nat.h. */ |
| 427 | |
| 428 | int |
| 429 | thread_db_notice_clone (ptid_t parent, ptid_t child) |
| 430 | { |
| 431 | td_thrhandle_t th; |
| 432 | td_thrinfo_t ti; |
| 433 | td_err_e err; |
| 434 | struct thread_db_info *info; |
| 435 | |
| 436 | info = get_thread_db_info (ptid_get_pid (child)); |
| 437 | |
| 438 | if (info == NULL) |
| 439 | return 0; |
| 440 | |
| 441 | thread_from_lwp (child); |
| 442 | |
| 443 | /* If we do not know about the main thread yet, this would be a good |
| 444 | time to find it. */ |
| 445 | thread_from_lwp (parent); |
| 446 | return 1; |
| 447 | } |
| 448 | |
| 449 | static void * |
| 450 | verbose_dlsym (void *handle, const char *name) |
| 451 | { |
| 452 | void *sym = dlsym (handle, name); |
| 453 | if (sym == NULL) |
| 454 | warning (_("Symbol \"%s\" not found in libthread_db: %s"), |
| 455 | name, dlerror ()); |
| 456 | return sym; |
| 457 | } |
| 458 | |
| 459 | static td_err_e |
| 460 | enable_thread_event (td_event_e event, CORE_ADDR *bp) |
| 461 | { |
| 462 | td_notify_t notify; |
| 463 | td_err_e err; |
| 464 | struct thread_db_info *info; |
| 465 | |
| 466 | info = get_thread_db_info (ptid_get_pid (inferior_ptid)); |
| 467 | |
| 468 | /* Access an lwp we know is stopped. */ |
| 469 | info->proc_handle.ptid = inferior_ptid; |
| 470 | |
| 471 | /* Get the breakpoint address for thread EVENT. */ |
| 472 | err = info->td_ta_event_addr_p (info->thread_agent, event, ¬ify); |
| 473 | if (err != TD_OK) |
| 474 | return err; |
| 475 | |
| 476 | /* Set up the breakpoint. */ |
| 477 | gdb_assert (exec_bfd); |
| 478 | (*bp) = (gdbarch_convert_from_func_ptr_addr |
| 479 | (target_gdbarch (), |
| 480 | /* Do proper sign extension for the target. */ |
| 481 | (bfd_get_sign_extend_vma (exec_bfd) > 0 |
| 482 | ? (CORE_ADDR) (intptr_t) notify.u.bptaddr |
| 483 | : (CORE_ADDR) (uintptr_t) notify.u.bptaddr), |
| 484 | ¤t_target)); |
| 485 | create_thread_event_breakpoint (target_gdbarch (), *bp); |
| 486 | |
| 487 | return TD_OK; |
| 488 | } |
| 489 | |
| 490 | /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and |
| 491 | return 1 if this version is lower (and not equal) to |
| 492 | VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */ |
| 493 | |
| 494 | static int |
| 495 | inferior_has_bug (const char *ver_symbol, int ver_major_min, int ver_minor_min) |
| 496 | { |
| 497 | struct bound_minimal_symbol version_msym; |
| 498 | CORE_ADDR version_addr; |
| 499 | char *version; |
| 500 | int err, got, retval = 0; |
| 501 | |
| 502 | version_msym = lookup_minimal_symbol (ver_symbol, NULL, NULL); |
| 503 | if (version_msym.minsym == NULL) |
| 504 | return 0; |
| 505 | |
| 506 | version_addr = BMSYMBOL_VALUE_ADDRESS (version_msym); |
| 507 | got = target_read_string (version_addr, &version, 32, &err); |
| 508 | if (err == 0 && memchr (version, 0, got) == &version[got -1]) |
| 509 | { |
| 510 | int major, minor; |
| 511 | |
| 512 | retval = (sscanf (version, "%d.%d", &major, &minor) == 2 |
| 513 | && (major < ver_major_min |
| 514 | || (major == ver_major_min && minor < ver_minor_min))); |
| 515 | } |
| 516 | xfree (version); |
| 517 | |
| 518 | return retval; |
| 519 | } |
| 520 | |
| 521 | static void |
| 522 | enable_thread_event_reporting (void) |
| 523 | { |
| 524 | td_thr_events_t events; |
| 525 | td_err_e err; |
| 526 | struct thread_db_info *info; |
| 527 | |
| 528 | info = get_thread_db_info (ptid_get_pid (inferior_ptid)); |
| 529 | |
| 530 | /* We cannot use the thread event reporting facility if these |
| 531 | functions aren't available. */ |
| 532 | if (info->td_ta_event_addr_p == NULL |
| 533 | || info->td_ta_set_event_p == NULL |
| 534 | || info->td_ta_event_getmsg_p == NULL |
| 535 | || info->td_thr_event_enable_p == NULL) |
| 536 | return; |
| 537 | |
| 538 | /* Set the process wide mask saying which events we're interested in. */ |
| 539 | td_event_emptyset (&events); |
| 540 | td_event_addset (&events, TD_CREATE); |
| 541 | |
| 542 | /* There is a bug fixed between linuxthreads 2.1.3 and 2.2 by |
| 543 | commit 2e4581e4fba917f1779cd0a010a45698586c190a |
| 544 | * manager.c (pthread_exited): Correctly report event as TD_REAP |
| 545 | instead of TD_DEATH. Fix comments. |
| 546 | where event reporting facility is broken for TD_DEATH events, |
| 547 | so don't enable it if we have glibc but a lower version. */ |
| 548 | if (!inferior_has_bug ("__linuxthreads_version", 2, 2)) |
| 549 | td_event_addset (&events, TD_DEATH); |
| 550 | |
| 551 | err = info->td_ta_set_event_p (info->thread_agent, &events); |
| 552 | if (err != TD_OK) |
| 553 | { |
| 554 | warning (_("Unable to set global thread event mask: %s"), |
| 555 | thread_db_err_str (err)); |
| 556 | return; |
| 557 | } |
| 558 | |
| 559 | /* Delete previous thread event breakpoints, if any. */ |
| 560 | remove_thread_event_breakpoints (); |
| 561 | info->td_create_bp_addr = 0; |
| 562 | info->td_death_bp_addr = 0; |
| 563 | |
| 564 | /* Set up the thread creation event. */ |
| 565 | err = enable_thread_event (TD_CREATE, &info->td_create_bp_addr); |
| 566 | if (err != TD_OK) |
| 567 | { |
| 568 | warning (_("Unable to get location for thread creation breakpoint: %s"), |
| 569 | thread_db_err_str (err)); |
| 570 | return; |
| 571 | } |
| 572 | |
| 573 | /* Set up the thread death event. */ |
| 574 | err = enable_thread_event (TD_DEATH, &info->td_death_bp_addr); |
| 575 | if (err != TD_OK) |
| 576 | { |
| 577 | warning (_("Unable to get location for thread death breakpoint: %s"), |
| 578 | thread_db_err_str (err)); |
| 579 | return; |
| 580 | } |
| 581 | } |
| 582 | |
| 583 | /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors |
| 584 | if appropriate. |
| 585 | |
| 586 | Return 1 if the caller should abort libthread_db initialization. Return 0 |
| 587 | otherwise. */ |
| 588 | |
| 589 | static int |
| 590 | thread_db_find_new_threads_silently (ptid_t ptid) |
| 591 | { |
| 592 | |
| 593 | TRY |
| 594 | { |
| 595 | thread_db_find_new_threads_2 (ptid, 1); |
| 596 | } |
| 597 | |
| 598 | CATCH (except, RETURN_MASK_ERROR) |
| 599 | { |
| 600 | if (libthread_db_debug) |
| 601 | exception_fprintf (gdb_stdlog, except, |
| 602 | "Warning: thread_db_find_new_threads_silently: "); |
| 603 | |
| 604 | /* There is a bug fixed between nptl 2.6.1 and 2.7 by |
| 605 | commit 7d9d8bd18906fdd17364f372b160d7ab896ce909 |
| 606 | where calls to td_thr_get_info fail with TD_ERR for statically linked |
| 607 | executables if td_thr_get_info is called before glibc has initialized |
| 608 | itself. |
| 609 | |
| 610 | If the nptl bug is NOT present in the inferior and still thread_db |
| 611 | reports an error return 1. It means the inferior has corrupted thread |
| 612 | list and GDB should fall back only to LWPs. |
| 613 | |
| 614 | If the nptl bug is present in the inferior return 0 to silently ignore |
| 615 | such errors, and let gdb enumerate threads again later. In such case |
| 616 | GDB cannot properly display LWPs if the inferior thread list is |
| 617 | corrupted. For core files it does not apply, no 'later enumeration' |
| 618 | is possible. */ |
| 619 | |
| 620 | if (!target_has_execution || !inferior_has_bug ("nptl_version", 2, 7)) |
| 621 | { |
| 622 | exception_fprintf (gdb_stderr, except, |
| 623 | _("Warning: couldn't activate thread debugging " |
| 624 | "using libthread_db: ")); |
| 625 | return 1; |
| 626 | } |
| 627 | } |
| 628 | END_CATCH |
| 629 | |
| 630 | return 0; |
| 631 | } |
| 632 | |
| 633 | /* Lookup a library in which given symbol resides. |
| 634 | Note: this is looking in GDB process, not in the inferior. |
| 635 | Returns library name, or NULL. */ |
| 636 | |
| 637 | static const char * |
| 638 | dladdr_to_soname (const void *addr) |
| 639 | { |
| 640 | Dl_info info; |
| 641 | |
| 642 | if (dladdr (addr, &info) != 0) |
| 643 | return info.dli_fname; |
| 644 | return NULL; |
| 645 | } |
| 646 | |
| 647 | /* Attempt to initialize dlopen()ed libthread_db, described by INFO. |
| 648 | Return 1 on success. |
| 649 | Failure could happen if libthread_db does not have symbols we expect, |
| 650 | or when it refuses to work with the current inferior (e.g. due to |
| 651 | version mismatch between libthread_db and libpthread). */ |
| 652 | |
| 653 | static int |
| 654 | try_thread_db_load_1 (struct thread_db_info *info) |
| 655 | { |
| 656 | td_err_e err; |
| 657 | |
| 658 | /* Initialize pointers to the dynamic library functions we will use. |
| 659 | Essential functions first. */ |
| 660 | |
| 661 | #define TDB_VERBOSE_DLSYM(info, func) \ |
| 662 | info->func ## _p = (func ## _ftype *) verbose_dlsym (info->handle, #func) |
| 663 | |
| 664 | #define TDB_DLSYM(info, func) \ |
| 665 | info->func ## _p = (func ## _ftype *) dlsym (info->handle, #func) |
| 666 | |
| 667 | #define CHK(a) \ |
| 668 | do \ |
| 669 | { \ |
| 670 | if ((a) == NULL) \ |
| 671 | return 0; \ |
| 672 | } while (0) |
| 673 | |
| 674 | CHK (TDB_VERBOSE_DLSYM (info, td_init)); |
| 675 | |
| 676 | err = info->td_init_p (); |
| 677 | if (err != TD_OK) |
| 678 | { |
| 679 | warning (_("Cannot initialize libthread_db: %s"), |
| 680 | thread_db_err_str (err)); |
| 681 | return 0; |
| 682 | } |
| 683 | |
| 684 | CHK (TDB_VERBOSE_DLSYM (info, td_ta_new)); |
| 685 | |
| 686 | /* Initialize the structure that identifies the child process. */ |
| 687 | info->proc_handle.ptid = inferior_ptid; |
| 688 | |
| 689 | /* Now attempt to open a connection to the thread library. */ |
| 690 | err = info->td_ta_new_p (&info->proc_handle, &info->thread_agent); |
| 691 | if (err != TD_OK) |
| 692 | { |
| 693 | if (libthread_db_debug) |
| 694 | fprintf_unfiltered (gdb_stdlog, _("td_ta_new failed: %s\n"), |
| 695 | thread_db_err_str (err)); |
| 696 | else |
| 697 | switch (err) |
| 698 | { |
| 699 | case TD_NOLIBTHREAD: |
| 700 | #ifdef THREAD_DB_HAS_TD_VERSION |
| 701 | case TD_VERSION: |
| 702 | #endif |
| 703 | /* The errors above are not unexpected and silently ignored: |
| 704 | they just mean we haven't found correct version of |
| 705 | libthread_db yet. */ |
| 706 | break; |
| 707 | default: |
| 708 | warning (_("td_ta_new failed: %s"), thread_db_err_str (err)); |
| 709 | } |
| 710 | return 0; |
| 711 | } |
| 712 | |
| 713 | /* These are essential. */ |
| 714 | CHK (TDB_VERBOSE_DLSYM (info, td_ta_map_lwp2thr)); |
| 715 | CHK (TDB_VERBOSE_DLSYM (info, td_ta_thr_iter)); |
| 716 | CHK (TDB_VERBOSE_DLSYM (info, td_thr_validate)); |
| 717 | CHK (TDB_VERBOSE_DLSYM (info, td_thr_get_info)); |
| 718 | |
| 719 | /* These are not essential. */ |
| 720 | TDB_DLSYM (info, td_ta_event_addr); |
| 721 | TDB_DLSYM (info, td_ta_set_event); |
| 722 | TDB_DLSYM (info, td_ta_clear_event); |
| 723 | TDB_DLSYM (info, td_ta_event_getmsg); |
| 724 | TDB_DLSYM (info, td_thr_event_enable); |
| 725 | TDB_DLSYM (info, td_thr_tls_get_addr); |
| 726 | TDB_DLSYM (info, td_thr_tlsbase); |
| 727 | |
| 728 | #undef TDB_VERBOSE_DLSYM |
| 729 | #undef TDB_DLSYM |
| 730 | #undef CHK |
| 731 | |
| 732 | /* It's best to avoid td_ta_thr_iter if possible. That walks data |
| 733 | structures in the inferior's address space that may be corrupted, |
| 734 | or, if the target is running, may change while we walk them. If |
| 735 | there's execution (and /proc is mounted), then we're already |
| 736 | attached to all LWPs. Use thread_from_lwp, which uses |
| 737 | td_ta_map_lwp2thr instead, which does not walk the thread list. |
| 738 | |
| 739 | td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that |
| 740 | currently on core targets, as it uses ptrace directly. */ |
| 741 | if (target_has_execution |
| 742 | && linux_proc_task_list_dir_exists (ptid_get_pid (inferior_ptid))) |
| 743 | { |
| 744 | struct lwp_info *lp; |
| 745 | int pid = ptid_get_pid (inferior_ptid); |
| 746 | |
| 747 | linux_stop_and_wait_all_lwps (); |
| 748 | |
| 749 | ALL_LWPS (lp) |
| 750 | if (ptid_get_pid (lp->ptid) == pid) |
| 751 | thread_from_lwp (lp->ptid); |
| 752 | |
| 753 | linux_unstop_all_lwps (); |
| 754 | } |
| 755 | else if (thread_db_find_new_threads_silently (inferior_ptid) != 0) |
| 756 | { |
| 757 | /* Even if libthread_db initializes, if the thread list is |
| 758 | corrupted, we'd not manage to list any threads. Better reject this |
| 759 | thread_db, and fall back to at least listing LWPs. */ |
| 760 | return 0; |
| 761 | } |
| 762 | |
| 763 | printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n")); |
| 764 | |
| 765 | if (*libthread_db_search_path || libthread_db_debug) |
| 766 | { |
| 767 | struct ui_file *file; |
| 768 | const char *library; |
| 769 | |
| 770 | library = dladdr_to_soname (*info->td_ta_new_p); |
| 771 | if (library == NULL) |
| 772 | library = LIBTHREAD_DB_SO; |
| 773 | |
| 774 | /* If we'd print this to gdb_stdout when debug output is |
| 775 | disabled, still print it to gdb_stdout if debug output is |
| 776 | enabled. User visible output should not depend on debug |
| 777 | settings. */ |
| 778 | file = *libthread_db_search_path != '\0' ? gdb_stdout : gdb_stdlog; |
| 779 | fprintf_unfiltered (file, _("Using host libthread_db library \"%s\".\n"), |
| 780 | library); |
| 781 | } |
| 782 | |
| 783 | /* The thread library was detected. Activate the thread_db target |
| 784 | if this is the first process using it. */ |
| 785 | if (thread_db_list->next == NULL) |
| 786 | push_target (&thread_db_ops); |
| 787 | |
| 788 | /* Enable event reporting, but not when debugging a core file. */ |
| 789 | if (target_has_execution && thread_db_use_events ()) |
| 790 | enable_thread_event_reporting (); |
| 791 | |
| 792 | return 1; |
| 793 | } |
| 794 | |
| 795 | /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute, |
| 796 | relative, or just LIBTHREAD_DB. */ |
| 797 | |
| 798 | static int |
| 799 | try_thread_db_load (const char *library, int check_auto_load_safe) |
| 800 | { |
| 801 | void *handle; |
| 802 | struct thread_db_info *info; |
| 803 | |
| 804 | if (libthread_db_debug) |
| 805 | fprintf_unfiltered (gdb_stdlog, |
| 806 | _("Trying host libthread_db library: %s.\n"), |
| 807 | library); |
| 808 | |
| 809 | if (check_auto_load_safe) |
| 810 | { |
| 811 | if (access (library, R_OK) != 0) |
| 812 | { |
| 813 | /* Do not print warnings by file_is_auto_load_safe if the library does |
| 814 | not exist at this place. */ |
| 815 | if (libthread_db_debug) |
| 816 | fprintf_unfiltered (gdb_stdlog, _("open failed: %s.\n"), |
| 817 | safe_strerror (errno)); |
| 818 | return 0; |
| 819 | } |
| 820 | |
| 821 | if (!file_is_auto_load_safe (library, _("auto-load: Loading libthread-db " |
| 822 | "library \"%s\" from explicit " |
| 823 | "directory.\n"), |
| 824 | library)) |
| 825 | return 0; |
| 826 | } |
| 827 | |
| 828 | handle = dlopen (library, RTLD_NOW); |
| 829 | if (handle == NULL) |
| 830 | { |
| 831 | if (libthread_db_debug) |
| 832 | fprintf_unfiltered (gdb_stdlog, _("dlopen failed: %s.\n"), dlerror ()); |
| 833 | return 0; |
| 834 | } |
| 835 | |
| 836 | if (libthread_db_debug && strchr (library, '/') == NULL) |
| 837 | { |
| 838 | void *td_init; |
| 839 | |
| 840 | td_init = dlsym (handle, "td_init"); |
| 841 | if (td_init != NULL) |
| 842 | { |
| 843 | const char *const libpath = dladdr_to_soname (td_init); |
| 844 | |
| 845 | if (libpath != NULL) |
| 846 | fprintf_unfiltered (gdb_stdlog, _("Host %s resolved to: %s.\n"), |
| 847 | library, libpath); |
| 848 | } |
| 849 | } |
| 850 | |
| 851 | info = add_thread_db_info (handle); |
| 852 | |
| 853 | /* Do not save system library name, that one is always trusted. */ |
| 854 | if (strchr (library, '/') != NULL) |
| 855 | info->filename = gdb_realpath (library); |
| 856 | |
| 857 | if (try_thread_db_load_1 (info)) |
| 858 | return 1; |
| 859 | |
| 860 | /* This library "refused" to work on current inferior. */ |
| 861 | delete_thread_db_info (ptid_get_pid (inferior_ptid)); |
| 862 | return 0; |
| 863 | } |
| 864 | |
| 865 | /* Subroutine of try_thread_db_load_from_pdir to simplify it. |
| 866 | Try loading libthread_db in directory(OBJ)/SUBDIR. |
| 867 | SUBDIR may be NULL. It may also be something like "../lib64". |
| 868 | The result is true for success. */ |
| 869 | |
| 870 | static int |
| 871 | try_thread_db_load_from_pdir_1 (struct objfile *obj, const char *subdir) |
| 872 | { |
| 873 | struct cleanup *cleanup; |
| 874 | char *path, *cp; |
| 875 | int result; |
| 876 | const char *obj_name = objfile_name (obj); |
| 877 | |
| 878 | if (obj_name[0] != '/') |
| 879 | { |
| 880 | warning (_("Expected absolute pathname for libpthread in the" |
| 881 | " inferior, but got %s."), obj_name); |
| 882 | return 0; |
| 883 | } |
| 884 | |
| 885 | path = xmalloc (strlen (obj_name) + (subdir ? strlen (subdir) + 1 : 0) |
| 886 | + 1 + strlen (LIBTHREAD_DB_SO) + 1); |
| 887 | cleanup = make_cleanup (xfree, path); |
| 888 | |
| 889 | strcpy (path, obj_name); |
| 890 | cp = strrchr (path, '/'); |
| 891 | /* This should at minimum hit the first character. */ |
| 892 | gdb_assert (cp != NULL); |
| 893 | cp[1] = '\0'; |
| 894 | if (subdir != NULL) |
| 895 | { |
| 896 | strcat (cp, subdir); |
| 897 | strcat (cp, "/"); |
| 898 | } |
| 899 | strcat (cp, LIBTHREAD_DB_SO); |
| 900 | |
| 901 | result = try_thread_db_load (path, 1); |
| 902 | |
| 903 | do_cleanups (cleanup); |
| 904 | return result; |
| 905 | } |
| 906 | |
| 907 | /* Handle $pdir in libthread-db-search-path. |
| 908 | Look for libthread_db in directory(libpthread)/SUBDIR. |
| 909 | SUBDIR may be NULL. It may also be something like "../lib64". |
| 910 | The result is true for success. */ |
| 911 | |
| 912 | static int |
| 913 | try_thread_db_load_from_pdir (const char *subdir) |
| 914 | { |
| 915 | struct objfile *obj; |
| 916 | |
| 917 | if (!auto_load_thread_db) |
| 918 | return 0; |
| 919 | |
| 920 | ALL_OBJFILES (obj) |
| 921 | if (libpthread_name_p (objfile_name (obj))) |
| 922 | { |
| 923 | if (try_thread_db_load_from_pdir_1 (obj, subdir)) |
| 924 | return 1; |
| 925 | |
| 926 | /* We may have found the separate-debug-info version of |
| 927 | libpthread, and it may live in a directory without a matching |
| 928 | libthread_db. */ |
| 929 | if (obj->separate_debug_objfile_backlink != NULL) |
| 930 | return try_thread_db_load_from_pdir_1 (obj->separate_debug_objfile_backlink, |
| 931 | subdir); |
| 932 | |
| 933 | return 0; |
| 934 | } |
| 935 | |
| 936 | return 0; |
| 937 | } |
| 938 | |
| 939 | /* Handle $sdir in libthread-db-search-path. |
| 940 | Look for libthread_db in the system dirs, or wherever a plain |
| 941 | dlopen(file_without_path) will look. |
| 942 | The result is true for success. */ |
| 943 | |
| 944 | static int |
| 945 | try_thread_db_load_from_sdir (void) |
| 946 | { |
| 947 | return try_thread_db_load (LIBTHREAD_DB_SO, 0); |
| 948 | } |
| 949 | |
| 950 | /* Try to load libthread_db from directory DIR of length DIR_LEN. |
| 951 | The result is true for success. */ |
| 952 | |
| 953 | static int |
| 954 | try_thread_db_load_from_dir (const char *dir, size_t dir_len) |
| 955 | { |
| 956 | struct cleanup *cleanup; |
| 957 | char *path; |
| 958 | int result; |
| 959 | |
| 960 | if (!auto_load_thread_db) |
| 961 | return 0; |
| 962 | |
| 963 | path = xmalloc (dir_len + 1 + strlen (LIBTHREAD_DB_SO) + 1); |
| 964 | cleanup = make_cleanup (xfree, path); |
| 965 | |
| 966 | memcpy (path, dir, dir_len); |
| 967 | path[dir_len] = '/'; |
| 968 | strcpy (path + dir_len + 1, LIBTHREAD_DB_SO); |
| 969 | |
| 970 | result = try_thread_db_load (path, 1); |
| 971 | |
| 972 | do_cleanups (cleanup); |
| 973 | return result; |
| 974 | } |
| 975 | |
| 976 | /* Search libthread_db_search_path for libthread_db which "agrees" |
| 977 | to work on current inferior. |
| 978 | The result is true for success. */ |
| 979 | |
| 980 | static int |
| 981 | thread_db_load_search (void) |
| 982 | { |
| 983 | VEC (char_ptr) *dir_vec; |
| 984 | struct cleanup *cleanups; |
| 985 | char *this_dir; |
| 986 | int i, rc = 0; |
| 987 | |
| 988 | dir_vec = dirnames_to_char_ptr_vec (libthread_db_search_path); |
| 989 | cleanups = make_cleanup_free_char_ptr_vec (dir_vec); |
| 990 | |
| 991 | for (i = 0; VEC_iterate (char_ptr, dir_vec, i, this_dir); ++i) |
| 992 | { |
| 993 | const int pdir_len = sizeof ("$pdir") - 1; |
| 994 | size_t this_dir_len; |
| 995 | |
| 996 | this_dir_len = strlen (this_dir); |
| 997 | |
| 998 | if (strncmp (this_dir, "$pdir", pdir_len) == 0 |
| 999 | && (this_dir[pdir_len] == '\0' |
| 1000 | || this_dir[pdir_len] == '/')) |
| 1001 | { |
| 1002 | char *subdir = NULL; |
| 1003 | struct cleanup *free_subdir_cleanup |
| 1004 | = make_cleanup (null_cleanup, NULL); |
| 1005 | |
| 1006 | if (this_dir[pdir_len] == '/') |
| 1007 | { |
| 1008 | subdir = xmalloc (strlen (this_dir)); |
| 1009 | make_cleanup (xfree, subdir); |
| 1010 | strcpy (subdir, this_dir + pdir_len + 1); |
| 1011 | } |
| 1012 | rc = try_thread_db_load_from_pdir (subdir); |
| 1013 | do_cleanups (free_subdir_cleanup); |
| 1014 | if (rc) |
| 1015 | break; |
| 1016 | } |
| 1017 | else if (strcmp (this_dir, "$sdir") == 0) |
| 1018 | { |
| 1019 | if (try_thread_db_load_from_sdir ()) |
| 1020 | { |
| 1021 | rc = 1; |
| 1022 | break; |
| 1023 | } |
| 1024 | } |
| 1025 | else |
| 1026 | { |
| 1027 | if (try_thread_db_load_from_dir (this_dir, this_dir_len)) |
| 1028 | { |
| 1029 | rc = 1; |
| 1030 | break; |
| 1031 | } |
| 1032 | } |
| 1033 | } |
| 1034 | |
| 1035 | do_cleanups (cleanups); |
| 1036 | if (libthread_db_debug) |
| 1037 | fprintf_unfiltered (gdb_stdlog, |
| 1038 | _("thread_db_load_search returning %d\n"), rc); |
| 1039 | return rc; |
| 1040 | } |
| 1041 | |
| 1042 | /* Return non-zero if the inferior has a libpthread. */ |
| 1043 | |
| 1044 | static int |
| 1045 | has_libpthread (void) |
| 1046 | { |
| 1047 | struct objfile *obj; |
| 1048 | |
| 1049 | ALL_OBJFILES (obj) |
| 1050 | if (libpthread_name_p (objfile_name (obj))) |
| 1051 | return 1; |
| 1052 | |
| 1053 | return 0; |
| 1054 | } |
| 1055 | |
| 1056 | /* Attempt to load and initialize libthread_db. |
| 1057 | Return 1 on success. */ |
| 1058 | |
| 1059 | static int |
| 1060 | thread_db_load (void) |
| 1061 | { |
| 1062 | struct thread_db_info *info; |
| 1063 | |
| 1064 | info = get_thread_db_info (ptid_get_pid (inferior_ptid)); |
| 1065 | |
| 1066 | if (info != NULL) |
| 1067 | return 1; |
| 1068 | |
| 1069 | /* Don't attempt to use thread_db on executables not running |
| 1070 | yet. */ |
| 1071 | if (!target_has_registers) |
| 1072 | return 0; |
| 1073 | |
| 1074 | /* Don't attempt to use thread_db for remote targets. */ |
| 1075 | if (!(target_can_run (¤t_target) || core_bfd)) |
| 1076 | return 0; |
| 1077 | |
| 1078 | if (thread_db_load_search ()) |
| 1079 | return 1; |
| 1080 | |
| 1081 | /* We couldn't find a libthread_db. |
| 1082 | If the inferior has a libpthread warn the user. */ |
| 1083 | if (has_libpthread ()) |
| 1084 | { |
| 1085 | warning (_("Unable to find libthread_db matching inferior's thread" |
| 1086 | " library, thread debugging will not be available.")); |
| 1087 | return 0; |
| 1088 | } |
| 1089 | |
| 1090 | /* Either this executable isn't using libpthread at all, or it is |
| 1091 | statically linked. Since we can't easily distinguish these two cases, |
| 1092 | no warning is issued. */ |
| 1093 | return 0; |
| 1094 | } |
| 1095 | |
| 1096 | static void |
| 1097 | disable_thread_event_reporting (struct thread_db_info *info) |
| 1098 | { |
| 1099 | if (info->td_ta_clear_event_p != NULL) |
| 1100 | { |
| 1101 | td_thr_events_t events; |
| 1102 | |
| 1103 | /* Set the process wide mask saying we aren't interested in any |
| 1104 | events anymore. */ |
| 1105 | td_event_fillset (&events); |
| 1106 | info->td_ta_clear_event_p (info->thread_agent, &events); |
| 1107 | } |
| 1108 | |
| 1109 | info->td_create_bp_addr = 0; |
| 1110 | info->td_death_bp_addr = 0; |
| 1111 | } |
| 1112 | |
| 1113 | static void |
| 1114 | check_thread_signals (void) |
| 1115 | { |
| 1116 | if (!thread_signals) |
| 1117 | { |
| 1118 | sigset_t mask; |
| 1119 | int i; |
| 1120 | |
| 1121 | lin_thread_get_thread_signals (&mask); |
| 1122 | sigemptyset (&thread_stop_set); |
| 1123 | sigemptyset (&thread_print_set); |
| 1124 | |
| 1125 | for (i = 1; i < NSIG; i++) |
| 1126 | { |
| 1127 | if (sigismember (&mask, i)) |
| 1128 | { |
| 1129 | if (signal_stop_update (gdb_signal_from_host (i), 0)) |
| 1130 | sigaddset (&thread_stop_set, i); |
| 1131 | if (signal_print_update (gdb_signal_from_host (i), 0)) |
| 1132 | sigaddset (&thread_print_set, i); |
| 1133 | thread_signals = 1; |
| 1134 | } |
| 1135 | } |
| 1136 | } |
| 1137 | } |
| 1138 | |
| 1139 | /* Check whether thread_db is usable. This function is called when |
| 1140 | an inferior is created (or otherwise acquired, e.g. attached to) |
| 1141 | and when new shared libraries are loaded into a running process. */ |
| 1142 | |
| 1143 | void |
| 1144 | check_for_thread_db (void) |
| 1145 | { |
| 1146 | /* Do nothing if we couldn't load libthread_db.so.1. */ |
| 1147 | if (!thread_db_load ()) |
| 1148 | return; |
| 1149 | } |
| 1150 | |
| 1151 | /* This function is called via the new_objfile observer. */ |
| 1152 | |
| 1153 | static void |
| 1154 | thread_db_new_objfile (struct objfile *objfile) |
| 1155 | { |
| 1156 | /* This observer must always be called with inferior_ptid set |
| 1157 | correctly. */ |
| 1158 | |
| 1159 | if (objfile != NULL |
| 1160 | /* libpthread with separate debug info has its debug info file already |
| 1161 | loaded (and notified without successful thread_db initialization) |
| 1162 | the time observer_notify_new_objfile is called for the library itself. |
| 1163 | Static executables have their separate debug info loaded already |
| 1164 | before the inferior has started. */ |
| 1165 | && objfile->separate_debug_objfile_backlink == NULL |
| 1166 | /* Only check for thread_db if we loaded libpthread, |
| 1167 | or if this is the main symbol file. |
| 1168 | We need to check OBJF_MAINLINE to handle the case of debugging |
| 1169 | a statically linked executable AND the symbol file is specified AFTER |
| 1170 | the exec file is loaded (e.g., gdb -c core ; file foo). |
| 1171 | For dynamically linked executables, libpthread can be near the end |
| 1172 | of the list of shared libraries to load, and in an app of several |
| 1173 | thousand shared libraries, this can otherwise be painful. */ |
| 1174 | && ((objfile->flags & OBJF_MAINLINE) != 0 |
| 1175 | || libpthread_name_p (objfile_name (objfile)))) |
| 1176 | check_for_thread_db (); |
| 1177 | } |
| 1178 | |
| 1179 | static void |
| 1180 | check_pid_namespace_match (void) |
| 1181 | { |
| 1182 | /* Check is only relevant for local targets targets. */ |
| 1183 | if (target_can_run (¤t_target)) |
| 1184 | { |
| 1185 | /* If the child is in a different PID namespace, its idea of its |
| 1186 | PID will differ from our idea of its PID. When we scan the |
| 1187 | child's thread list, we'll mistakenly think it has no threads |
| 1188 | since the thread PID fields won't match the PID we give to |
| 1189 | libthread_db. */ |
| 1190 | if (!linux_ns_same (ptid_get_pid (inferior_ptid), LINUX_NS_PID)) |
| 1191 | { |
| 1192 | warning (_ ("Target and debugger are in different PID " |
| 1193 | "namespaces; thread lists and other data are " |
| 1194 | "likely unreliable")); |
| 1195 | } |
| 1196 | } |
| 1197 | } |
| 1198 | |
| 1199 | /* This function is called via the inferior_created observer. |
| 1200 | This handles the case of debugging statically linked executables. */ |
| 1201 | |
| 1202 | static void |
| 1203 | thread_db_inferior_created (struct target_ops *target, int from_tty) |
| 1204 | { |
| 1205 | check_pid_namespace_match (); |
| 1206 | check_for_thread_db (); |
| 1207 | } |
| 1208 | |
| 1209 | /* Update the thread's state (what's displayed in "info threads"), |
| 1210 | from libthread_db thread state information. */ |
| 1211 | |
| 1212 | static void |
| 1213 | update_thread_state (struct private_thread_info *priv, |
| 1214 | const td_thrinfo_t *ti_p) |
| 1215 | { |
| 1216 | priv->dying = (ti_p->ti_state == TD_THR_UNKNOWN |
| 1217 | || ti_p->ti_state == TD_THR_ZOMBIE); |
| 1218 | } |
| 1219 | |
| 1220 | /* Attach to a new thread. This function is called when we receive a |
| 1221 | TD_CREATE event or when we iterate over all threads and find one |
| 1222 | that wasn't already in our list. Returns true on success. */ |
| 1223 | |
| 1224 | static int |
| 1225 | attach_thread (ptid_t ptid, const td_thrhandle_t *th_p, |
| 1226 | const td_thrinfo_t *ti_p) |
| 1227 | { |
| 1228 | struct thread_info *tp; |
| 1229 | struct thread_db_info *info; |
| 1230 | |
| 1231 | /* If we're being called after a TD_CREATE event, we may already |
| 1232 | know about this thread. There are two ways this can happen. We |
| 1233 | may have iterated over all threads between the thread creation |
| 1234 | and the TD_CREATE event, for instance when the user has issued |
| 1235 | the `info threads' command before the SIGTRAP for hitting the |
| 1236 | thread creation breakpoint was reported. Alternatively, the |
| 1237 | thread may have exited and a new one been created with the same |
| 1238 | thread ID. In the first case we don't need to do anything; in |
| 1239 | the second case we should discard information about the dead |
| 1240 | thread and attach to the new one. */ |
| 1241 | tp = find_thread_ptid (ptid); |
| 1242 | if (tp != NULL) |
| 1243 | { |
| 1244 | /* If tp->priv is NULL, then GDB is already attached to this |
| 1245 | thread, but we do not know anything about it. We can learn |
| 1246 | about it here. This can only happen if we have some other |
| 1247 | way besides libthread_db to notice new threads (i.e. |
| 1248 | PTRACE_EVENT_CLONE); assume the same mechanism notices thread |
| 1249 | exit, so this can not be a stale thread recreated with the |
| 1250 | same ID. */ |
| 1251 | if (tp->priv != NULL) |
| 1252 | { |
| 1253 | if (!tp->priv->dying) |
| 1254 | return 0; |
| 1255 | |
| 1256 | delete_thread (ptid); |
| 1257 | tp = NULL; |
| 1258 | } |
| 1259 | } |
| 1260 | |
| 1261 | /* Under GNU/Linux, we have to attach to each and every thread. */ |
| 1262 | if (target_has_execution |
| 1263 | && tp == NULL) |
| 1264 | { |
| 1265 | int res; |
| 1266 | |
| 1267 | res = lin_lwp_attach_lwp (ptid_build (ptid_get_pid (ptid), |
| 1268 | ti_p->ti_lid, 0)); |
| 1269 | if (res < 0) |
| 1270 | { |
| 1271 | /* Error, stop iterating. */ |
| 1272 | return 0; |
| 1273 | } |
| 1274 | else if (res > 0) |
| 1275 | { |
| 1276 | /* Pretend this thread doesn't exist yet, and keep |
| 1277 | iterating. */ |
| 1278 | return 1; |
| 1279 | } |
| 1280 | |
| 1281 | /* Otherwise, we sucessfully attached to the thread. */ |
| 1282 | } |
| 1283 | |
| 1284 | info = get_thread_db_info (ptid_get_pid (ptid)); |
| 1285 | record_thread (info, tp, ptid, th_p, ti_p); |
| 1286 | return 1; |
| 1287 | } |
| 1288 | |
| 1289 | /* Record a new thread in GDB's thread list. Creates the thread's |
| 1290 | private info. If TP is NULL, creates a new thread. Otherwise, |
| 1291 | uses TP. */ |
| 1292 | |
| 1293 | static void |
| 1294 | record_thread (struct thread_db_info *info, |
| 1295 | struct thread_info *tp, |
| 1296 | ptid_t ptid, const td_thrhandle_t *th_p, |
| 1297 | const td_thrinfo_t *ti_p) |
| 1298 | { |
| 1299 | td_err_e err; |
| 1300 | struct private_thread_info *priv; |
| 1301 | int new_thread = (tp == NULL); |
| 1302 | |
| 1303 | /* A thread ID of zero may mean the thread library has not |
| 1304 | initialized yet. Leave private == NULL until the thread library |
| 1305 | has initialized. */ |
| 1306 | if (ti_p->ti_tid == 0) |
| 1307 | return; |
| 1308 | |
| 1309 | /* Construct the thread's private data. */ |
| 1310 | priv = XCNEW (struct private_thread_info); |
| 1311 | |
| 1312 | priv->th = *th_p; |
| 1313 | priv->tid = ti_p->ti_tid; |
| 1314 | update_thread_state (priv, ti_p); |
| 1315 | |
| 1316 | /* Add the thread to GDB's thread list. If we already know about a |
| 1317 | thread with this PTID, but it's marked exited, then the kernel |
| 1318 | reused the tid of an old thread. */ |
| 1319 | if (tp == NULL || tp->state == THREAD_EXITED) |
| 1320 | tp = add_thread_with_info (ptid, priv); |
| 1321 | else |
| 1322 | tp->priv = priv; |
| 1323 | |
| 1324 | /* Enable thread event reporting for this thread, except when |
| 1325 | debugging a core file. */ |
| 1326 | if (target_has_execution && thread_db_use_events () && new_thread) |
| 1327 | { |
| 1328 | err = info->td_thr_event_enable_p (th_p, 1); |
| 1329 | if (err != TD_OK) |
| 1330 | error (_("Cannot enable thread event reporting for %s: %s"), |
| 1331 | target_pid_to_str (ptid), thread_db_err_str (err)); |
| 1332 | } |
| 1333 | |
| 1334 | if (target_has_execution) |
| 1335 | check_thread_signals (); |
| 1336 | } |
| 1337 | |
| 1338 | static void |
| 1339 | detach_thread (ptid_t ptid) |
| 1340 | { |
| 1341 | struct thread_info *thread_info; |
| 1342 | |
| 1343 | /* Don't delete the thread now, because it still reports as active |
| 1344 | until it has executed a few instructions after the event |
| 1345 | breakpoint - if we deleted it now, "info threads" would cause us |
| 1346 | to re-attach to it. Just mark it as having had a TD_DEATH |
| 1347 | event. This means that we won't delete it from our thread list |
| 1348 | until we notice that it's dead (via prune_threads), or until |
| 1349 | something re-uses its thread ID. We'll report the thread exit |
| 1350 | when the underlying LWP dies. */ |
| 1351 | thread_info = find_thread_ptid (ptid); |
| 1352 | gdb_assert (thread_info != NULL && thread_info->priv != NULL); |
| 1353 | thread_info->priv->dying = 1; |
| 1354 | } |
| 1355 | |
| 1356 | static void |
| 1357 | thread_db_detach (struct target_ops *ops, const char *args, int from_tty) |
| 1358 | { |
| 1359 | struct target_ops *target_beneath = find_target_beneath (ops); |
| 1360 | struct thread_db_info *info; |
| 1361 | |
| 1362 | info = get_thread_db_info (ptid_get_pid (inferior_ptid)); |
| 1363 | |
| 1364 | if (info) |
| 1365 | { |
| 1366 | if (target_has_execution && thread_db_use_events ()) |
| 1367 | { |
| 1368 | disable_thread_event_reporting (info); |
| 1369 | |
| 1370 | /* Delete the old thread event breakpoints. Note that |
| 1371 | unlike when mourning, we can remove them here because |
| 1372 | there's still a live inferior to poke at. In any case, |
| 1373 | GDB will not try to insert anything in the inferior when |
| 1374 | removing a breakpoint. */ |
| 1375 | remove_thread_event_breakpoints (); |
| 1376 | } |
| 1377 | |
| 1378 | delete_thread_db_info (ptid_get_pid (inferior_ptid)); |
| 1379 | } |
| 1380 | |
| 1381 | target_beneath->to_detach (target_beneath, args, from_tty); |
| 1382 | |
| 1383 | /* NOTE: From this point on, inferior_ptid is null_ptid. */ |
| 1384 | |
| 1385 | /* If there are no more processes using libpthread, detach the |
| 1386 | thread_db target ops. */ |
| 1387 | if (!thread_db_list) |
| 1388 | unpush_target (&thread_db_ops); |
| 1389 | } |
| 1390 | |
| 1391 | /* Check if PID is currently stopped at the location of a thread event |
| 1392 | breakpoint location. If it is, read the event message and act upon |
| 1393 | the event. */ |
| 1394 | |
| 1395 | static void |
| 1396 | check_event (ptid_t ptid) |
| 1397 | { |
| 1398 | struct regcache *regcache = get_thread_regcache (ptid); |
| 1399 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 1400 | td_event_msg_t msg; |
| 1401 | td_thrinfo_t ti; |
| 1402 | td_err_e err; |
| 1403 | CORE_ADDR stop_pc; |
| 1404 | int loop = 0; |
| 1405 | struct thread_db_info *info; |
| 1406 | |
| 1407 | info = get_thread_db_info (ptid_get_pid (ptid)); |
| 1408 | |
| 1409 | /* Bail out early if we're not at a thread event breakpoint. */ |
| 1410 | stop_pc = regcache_read_pc (regcache); |
| 1411 | if (!target_supports_stopped_by_sw_breakpoint ()) |
| 1412 | stop_pc -= gdbarch_decr_pc_after_break (gdbarch); |
| 1413 | |
| 1414 | if (stop_pc != info->td_create_bp_addr |
| 1415 | && stop_pc != info->td_death_bp_addr) |
| 1416 | return; |
| 1417 | |
| 1418 | /* Access an lwp we know is stopped. */ |
| 1419 | info->proc_handle.ptid = ptid; |
| 1420 | |
| 1421 | /* If we have only looked at the first thread before libpthread was |
| 1422 | initialized, we may not know its thread ID yet. Make sure we do |
| 1423 | before we add another thread to the list. */ |
| 1424 | if (!have_threads (ptid)) |
| 1425 | thread_db_find_new_threads_1 (ptid); |
| 1426 | |
| 1427 | /* If we are at a create breakpoint, we do not know what new lwp |
| 1428 | was created and cannot specifically locate the event message for it. |
| 1429 | We have to call td_ta_event_getmsg() to get |
| 1430 | the latest message. Since we have no way of correlating whether |
| 1431 | the event message we get back corresponds to our breakpoint, we must |
| 1432 | loop and read all event messages, processing them appropriately. |
| 1433 | This guarantees we will process the correct message before continuing |
| 1434 | from the breakpoint. |
| 1435 | |
| 1436 | Currently, death events are not enabled. If they are enabled, |
| 1437 | the death event can use the td_thr_event_getmsg() interface to |
| 1438 | get the message specifically for that lwp and avoid looping |
| 1439 | below. */ |
| 1440 | |
| 1441 | loop = 1; |
| 1442 | |
| 1443 | do |
| 1444 | { |
| 1445 | err = info->td_ta_event_getmsg_p (info->thread_agent, &msg); |
| 1446 | if (err != TD_OK) |
| 1447 | { |
| 1448 | if (err == TD_NOMSG) |
| 1449 | return; |
| 1450 | |
| 1451 | error (_("Cannot get thread event message: %s"), |
| 1452 | thread_db_err_str (err)); |
| 1453 | } |
| 1454 | |
| 1455 | err = info->td_thr_get_info_p (msg.th_p, &ti); |
| 1456 | if (err != TD_OK) |
| 1457 | error (_("Cannot get thread info: %s"), thread_db_err_str (err)); |
| 1458 | |
| 1459 | ptid = ptid_build (ptid_get_pid (ptid), ti.ti_lid, 0); |
| 1460 | |
| 1461 | switch (msg.event) |
| 1462 | { |
| 1463 | case TD_CREATE: |
| 1464 | /* Call attach_thread whether or not we already know about a |
| 1465 | thread with this thread ID. */ |
| 1466 | attach_thread (ptid, msg.th_p, &ti); |
| 1467 | |
| 1468 | break; |
| 1469 | |
| 1470 | case TD_DEATH: |
| 1471 | |
| 1472 | if (!in_thread_list (ptid)) |
| 1473 | error (_("Spurious thread death event.")); |
| 1474 | |
| 1475 | detach_thread (ptid); |
| 1476 | |
| 1477 | break; |
| 1478 | |
| 1479 | default: |
| 1480 | error (_("Spurious thread event.")); |
| 1481 | } |
| 1482 | } |
| 1483 | while (loop); |
| 1484 | } |
| 1485 | |
| 1486 | static ptid_t |
| 1487 | thread_db_wait (struct target_ops *ops, |
| 1488 | ptid_t ptid, struct target_waitstatus *ourstatus, |
| 1489 | int options) |
| 1490 | { |
| 1491 | struct thread_db_info *info; |
| 1492 | struct target_ops *beneath = find_target_beneath (ops); |
| 1493 | |
| 1494 | ptid = beneath->to_wait (beneath, ptid, ourstatus, options); |
| 1495 | |
| 1496 | if (ourstatus->kind == TARGET_WAITKIND_IGNORE) |
| 1497 | return ptid; |
| 1498 | |
| 1499 | if (ourstatus->kind == TARGET_WAITKIND_EXITED |
| 1500 | || ourstatus->kind == TARGET_WAITKIND_SIGNALLED) |
| 1501 | return ptid; |
| 1502 | |
| 1503 | info = get_thread_db_info (ptid_get_pid (ptid)); |
| 1504 | |
| 1505 | /* If this process isn't using thread_db, we're done. */ |
| 1506 | if (info == NULL) |
| 1507 | return ptid; |
| 1508 | |
| 1509 | if (ourstatus->kind == TARGET_WAITKIND_EXECD) |
| 1510 | { |
| 1511 | /* New image, it may or may not end up using thread_db. Assume |
| 1512 | not unless we find otherwise. */ |
| 1513 | delete_thread_db_info (ptid_get_pid (ptid)); |
| 1514 | if (!thread_db_list) |
| 1515 | unpush_target (&thread_db_ops); |
| 1516 | |
| 1517 | /* Thread event breakpoints are deleted by |
| 1518 | update_breakpoints_after_exec. */ |
| 1519 | |
| 1520 | return ptid; |
| 1521 | } |
| 1522 | |
| 1523 | if (ourstatus->kind == TARGET_WAITKIND_STOPPED |
| 1524 | && ourstatus->value.sig == GDB_SIGNAL_TRAP) |
| 1525 | /* Check for a thread event. */ |
| 1526 | check_event (ptid); |
| 1527 | |
| 1528 | /* Fill in the thread's user-level thread id and status. */ |
| 1529 | thread_from_lwp (ptid); |
| 1530 | |
| 1531 | return ptid; |
| 1532 | } |
| 1533 | |
| 1534 | static void |
| 1535 | thread_db_mourn_inferior (struct target_ops *ops) |
| 1536 | { |
| 1537 | struct target_ops *target_beneath = find_target_beneath (ops); |
| 1538 | |
| 1539 | delete_thread_db_info (ptid_get_pid (inferior_ptid)); |
| 1540 | |
| 1541 | target_beneath->to_mourn_inferior (target_beneath); |
| 1542 | |
| 1543 | /* Delete the old thread event breakpoints. Do this after mourning |
| 1544 | the inferior, so that we don't try to uninsert them. */ |
| 1545 | remove_thread_event_breakpoints (); |
| 1546 | |
| 1547 | /* Detach thread_db target ops. */ |
| 1548 | if (!thread_db_list) |
| 1549 | unpush_target (ops); |
| 1550 | } |
| 1551 | |
| 1552 | struct callback_data |
| 1553 | { |
| 1554 | struct thread_db_info *info; |
| 1555 | int new_threads; |
| 1556 | }; |
| 1557 | |
| 1558 | static int |
| 1559 | find_new_threads_callback (const td_thrhandle_t *th_p, void *data) |
| 1560 | { |
| 1561 | td_thrinfo_t ti; |
| 1562 | td_err_e err; |
| 1563 | ptid_t ptid; |
| 1564 | struct thread_info *tp; |
| 1565 | struct callback_data *cb_data = data; |
| 1566 | struct thread_db_info *info = cb_data->info; |
| 1567 | |
| 1568 | err = info->td_thr_get_info_p (th_p, &ti); |
| 1569 | if (err != TD_OK) |
| 1570 | error (_("find_new_threads_callback: cannot get thread info: %s"), |
| 1571 | thread_db_err_str (err)); |
| 1572 | |
| 1573 | if (ti.ti_lid == -1) |
| 1574 | { |
| 1575 | /* A thread with kernel thread ID -1 is either a thread that |
| 1576 | exited and was joined, or a thread that is being created but |
| 1577 | hasn't started yet, and that is reusing the tcb/stack of a |
| 1578 | thread that previously exited and was joined. (glibc marks |
| 1579 | terminated and joined threads with kernel thread ID -1. See |
| 1580 | glibc PR17707. */ |
| 1581 | if (libthread_db_debug) |
| 1582 | fprintf_unfiltered (gdb_stdlog, |
| 1583 | "thread_db: skipping exited and " |
| 1584 | "joined thread (0x%lx)\n", ti.ti_tid); |
| 1585 | return 0; |
| 1586 | } |
| 1587 | |
| 1588 | if (ti.ti_tid == 0) |
| 1589 | { |
| 1590 | /* A thread ID of zero means that this is the main thread, but |
| 1591 | glibc has not yet initialized thread-local storage and the |
| 1592 | pthread library. We do not know what the thread's TID will |
| 1593 | be yet. Just enable event reporting and otherwise ignore |
| 1594 | it. */ |
| 1595 | |
| 1596 | /* In that case, we're not stopped in a fork syscall and don't |
| 1597 | need this glibc bug workaround. */ |
| 1598 | info->need_stale_parent_threads_check = 0; |
| 1599 | |
| 1600 | if (target_has_execution && thread_db_use_events ()) |
| 1601 | { |
| 1602 | err = info->td_thr_event_enable_p (th_p, 1); |
| 1603 | if (err != TD_OK) |
| 1604 | error (_("Cannot enable thread event reporting for LWP %d: %s"), |
| 1605 | (int) ti.ti_lid, thread_db_err_str (err)); |
| 1606 | } |
| 1607 | |
| 1608 | return 0; |
| 1609 | } |
| 1610 | |
| 1611 | /* Ignore stale parent threads, caused by glibc/BZ5983. This is a |
| 1612 | bit expensive, as it needs to open /proc/pid/status, so try to |
| 1613 | avoid doing the work if we know we don't have to. */ |
| 1614 | if (info->need_stale_parent_threads_check) |
| 1615 | { |
| 1616 | int tgid = linux_proc_get_tgid (ti.ti_lid); |
| 1617 | |
| 1618 | if (tgid != -1 && tgid != info->pid) |
| 1619 | return 0; |
| 1620 | } |
| 1621 | |
| 1622 | ptid = ptid_build (info->pid, ti.ti_lid, 0); |
| 1623 | tp = find_thread_ptid (ptid); |
| 1624 | if (tp == NULL || tp->priv == NULL) |
| 1625 | { |
| 1626 | if (attach_thread (ptid, th_p, &ti)) |
| 1627 | cb_data->new_threads += 1; |
| 1628 | else |
| 1629 | /* Problem attaching this thread; perhaps it exited before we |
| 1630 | could attach it? |
| 1631 | This could mean that the thread list inside glibc itself is in |
| 1632 | inconsistent state, and libthread_db could go on looping forever |
| 1633 | (observed with glibc-2.3.6). To prevent that, terminate |
| 1634 | iteration: thread_db_find_new_threads_2 will retry. */ |
| 1635 | return 1; |
| 1636 | } |
| 1637 | else if (target_has_execution && !thread_db_use_events ()) |
| 1638 | { |
| 1639 | /* Need to update this if not using the libthread_db events |
| 1640 | (particularly, the TD_DEATH event). */ |
| 1641 | update_thread_state (tp->priv, &ti); |
| 1642 | } |
| 1643 | |
| 1644 | return 0; |
| 1645 | } |
| 1646 | |
| 1647 | /* Helper for thread_db_find_new_threads_2. |
| 1648 | Returns number of new threads found. */ |
| 1649 | |
| 1650 | static int |
| 1651 | find_new_threads_once (struct thread_db_info *info, int iteration, |
| 1652 | td_err_e *errp) |
| 1653 | { |
| 1654 | struct callback_data data; |
| 1655 | td_err_e err = TD_ERR; |
| 1656 | |
| 1657 | data.info = info; |
| 1658 | data.new_threads = 0; |
| 1659 | |
| 1660 | /* See comment in thread_db_update_thread_list. */ |
| 1661 | gdb_assert (!target_has_execution || thread_db_use_events ()); |
| 1662 | |
| 1663 | TRY |
| 1664 | { |
| 1665 | /* Iterate over all user-space threads to discover new threads. */ |
| 1666 | err = info->td_ta_thr_iter_p (info->thread_agent, |
| 1667 | find_new_threads_callback, |
| 1668 | &data, |
| 1669 | TD_THR_ANY_STATE, |
| 1670 | TD_THR_LOWEST_PRIORITY, |
| 1671 | TD_SIGNO_MASK, |
| 1672 | TD_THR_ANY_USER_FLAGS); |
| 1673 | } |
| 1674 | CATCH (except, RETURN_MASK_ERROR) |
| 1675 | { |
| 1676 | if (libthread_db_debug) |
| 1677 | { |
| 1678 | exception_fprintf (gdb_stdlog, except, |
| 1679 | "Warning: find_new_threads_once: "); |
| 1680 | } |
| 1681 | } |
| 1682 | END_CATCH |
| 1683 | |
| 1684 | if (libthread_db_debug) |
| 1685 | { |
| 1686 | fprintf_unfiltered (gdb_stdlog, |
| 1687 | _("Found %d new threads in iteration %d.\n"), |
| 1688 | data.new_threads, iteration); |
| 1689 | } |
| 1690 | |
| 1691 | if (errp != NULL) |
| 1692 | *errp = err; |
| 1693 | |
| 1694 | return data.new_threads; |
| 1695 | } |
| 1696 | |
| 1697 | /* Search for new threads, accessing memory through stopped thread |
| 1698 | PTID. If UNTIL_NO_NEW is true, repeat searching until several |
| 1699 | searches in a row do not discover any new threads. */ |
| 1700 | |
| 1701 | static void |
| 1702 | thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new) |
| 1703 | { |
| 1704 | td_err_e err = TD_OK; |
| 1705 | struct thread_db_info *info; |
| 1706 | int i, loop; |
| 1707 | |
| 1708 | info = get_thread_db_info (ptid_get_pid (ptid)); |
| 1709 | |
| 1710 | /* Access an lwp we know is stopped. */ |
| 1711 | info->proc_handle.ptid = ptid; |
| 1712 | |
| 1713 | if (until_no_new) |
| 1714 | { |
| 1715 | /* Require 4 successive iterations which do not find any new threads. |
| 1716 | The 4 is a heuristic: there is an inherent race here, and I have |
| 1717 | seen that 2 iterations in a row are not always sufficient to |
| 1718 | "capture" all threads. */ |
| 1719 | for (i = 0, loop = 0; loop < 4 && err == TD_OK; ++i, ++loop) |
| 1720 | if (find_new_threads_once (info, i, &err) != 0) |
| 1721 | { |
| 1722 | /* Found some new threads. Restart the loop from beginning. */ |
| 1723 | loop = -1; |
| 1724 | } |
| 1725 | } |
| 1726 | else |
| 1727 | find_new_threads_once (info, 0, &err); |
| 1728 | |
| 1729 | if (err != TD_OK) |
| 1730 | error (_("Cannot find new threads: %s"), thread_db_err_str (err)); |
| 1731 | } |
| 1732 | |
| 1733 | static void |
| 1734 | thread_db_find_new_threads_1 (ptid_t ptid) |
| 1735 | { |
| 1736 | thread_db_find_new_threads_2 (ptid, 0); |
| 1737 | } |
| 1738 | |
| 1739 | static int |
| 1740 | update_thread_core (struct lwp_info *info, void *closure) |
| 1741 | { |
| 1742 | info->core = linux_common_core_of_thread (info->ptid); |
| 1743 | return 0; |
| 1744 | } |
| 1745 | |
| 1746 | /* Update the thread list using td_ta_thr_iter. */ |
| 1747 | |
| 1748 | static void |
| 1749 | thread_db_update_thread_list_td_ta_thr_iter (struct target_ops *ops) |
| 1750 | { |
| 1751 | struct thread_db_info *info; |
| 1752 | struct inferior *inf; |
| 1753 | |
| 1754 | prune_threads (); |
| 1755 | |
| 1756 | ALL_INFERIORS (inf) |
| 1757 | { |
| 1758 | struct thread_info *thread; |
| 1759 | |
| 1760 | if (inf->pid == 0) |
| 1761 | continue; |
| 1762 | |
| 1763 | info = get_thread_db_info (inf->pid); |
| 1764 | if (info == NULL) |
| 1765 | continue; |
| 1766 | |
| 1767 | thread = any_live_thread_of_process (inf->pid); |
| 1768 | if (thread == NULL || thread->executing) |
| 1769 | continue; |
| 1770 | |
| 1771 | thread_db_find_new_threads_1 (thread->ptid); |
| 1772 | } |
| 1773 | } |
| 1774 | |
| 1775 | /* Implement the to_update_thread_list target method for this |
| 1776 | target. */ |
| 1777 | |
| 1778 | static void |
| 1779 | thread_db_update_thread_list (struct target_ops *ops) |
| 1780 | { |
| 1781 | /* It's best to avoid td_ta_thr_iter if possible. That walks data |
| 1782 | structures in the inferior's address space that may be corrupted, |
| 1783 | or, if the target is running, the list may change while we walk |
| 1784 | it. In the latter case, it's possible that a thread exits just |
| 1785 | at the exact time that causes GDB to get stuck in an infinite |
| 1786 | loop. To avoid pausing all threads whenever the core wants to |
| 1787 | refresh the thread list, if the kernel supports clone events |
| 1788 | (meaning we're always already attached to all LWPs), we use |
| 1789 | thread_from_lwp immediately when we see an LWP stop. That uses |
| 1790 | thread_db entry points that do not walk libpthread's thread list, |
| 1791 | so should be safe, as well as more efficient. */ |
| 1792 | if (target_has_execution && !thread_db_use_events ()) |
| 1793 | ops->beneath->to_update_thread_list (ops->beneath); |
| 1794 | else |
| 1795 | thread_db_update_thread_list_td_ta_thr_iter (ops); |
| 1796 | |
| 1797 | if (target_has_execution) |
| 1798 | iterate_over_lwps (minus_one_ptid /* iterate over all */, |
| 1799 | update_thread_core, NULL); |
| 1800 | } |
| 1801 | |
| 1802 | static char * |
| 1803 | thread_db_pid_to_str (struct target_ops *ops, ptid_t ptid) |
| 1804 | { |
| 1805 | struct thread_info *thread_info = find_thread_ptid (ptid); |
| 1806 | struct target_ops *beneath; |
| 1807 | |
| 1808 | if (thread_info != NULL && thread_info->priv != NULL) |
| 1809 | { |
| 1810 | static char buf[64]; |
| 1811 | thread_t tid; |
| 1812 | |
| 1813 | tid = thread_info->priv->tid; |
| 1814 | snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)", |
| 1815 | tid, ptid_get_lwp (ptid)); |
| 1816 | |
| 1817 | return buf; |
| 1818 | } |
| 1819 | |
| 1820 | beneath = find_target_beneath (ops); |
| 1821 | return beneath->to_pid_to_str (beneath, ptid); |
| 1822 | } |
| 1823 | |
| 1824 | /* Return a string describing the state of the thread specified by |
| 1825 | INFO. */ |
| 1826 | |
| 1827 | static char * |
| 1828 | thread_db_extra_thread_info (struct target_ops *self, |
| 1829 | struct thread_info *info) |
| 1830 | { |
| 1831 | if (info->priv == NULL) |
| 1832 | return NULL; |
| 1833 | |
| 1834 | if (info->priv->dying) |
| 1835 | return "Exiting"; |
| 1836 | |
| 1837 | return NULL; |
| 1838 | } |
| 1839 | |
| 1840 | /* Get the address of the thread local variable in load module LM which |
| 1841 | is stored at OFFSET within the thread local storage for thread PTID. */ |
| 1842 | |
| 1843 | static CORE_ADDR |
| 1844 | thread_db_get_thread_local_address (struct target_ops *ops, |
| 1845 | ptid_t ptid, |
| 1846 | CORE_ADDR lm, |
| 1847 | CORE_ADDR offset) |
| 1848 | { |
| 1849 | struct thread_info *thread_info; |
| 1850 | struct target_ops *beneath; |
| 1851 | |
| 1852 | /* Find the matching thread. */ |
| 1853 | thread_info = find_thread_ptid (ptid); |
| 1854 | |
| 1855 | /* We may not have discovered the thread yet. */ |
| 1856 | if (thread_info != NULL && thread_info->priv == NULL) |
| 1857 | { |
| 1858 | thread_from_lwp (ptid); |
| 1859 | thread_info = find_thread_ptid (ptid); |
| 1860 | } |
| 1861 | |
| 1862 | if (thread_info != NULL && thread_info->priv != NULL) |
| 1863 | { |
| 1864 | td_err_e err; |
| 1865 | psaddr_t address; |
| 1866 | struct thread_db_info *info; |
| 1867 | |
| 1868 | info = get_thread_db_info (ptid_get_pid (ptid)); |
| 1869 | |
| 1870 | /* Finally, get the address of the variable. */ |
| 1871 | if (lm != 0) |
| 1872 | { |
| 1873 | /* glibc doesn't provide the needed interface. */ |
| 1874 | if (!info->td_thr_tls_get_addr_p) |
| 1875 | throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR, |
| 1876 | _("No TLS library support")); |
| 1877 | |
| 1878 | /* Note the cast through uintptr_t: this interface only works if |
| 1879 | a target address fits in a psaddr_t, which is a host pointer. |
| 1880 | So a 32-bit debugger can not access 64-bit TLS through this. */ |
| 1881 | err = info->td_thr_tls_get_addr_p (&thread_info->priv->th, |
| 1882 | (psaddr_t)(uintptr_t) lm, |
| 1883 | offset, &address); |
| 1884 | } |
| 1885 | else |
| 1886 | { |
| 1887 | /* If glibc doesn't provide the needed interface throw an error |
| 1888 | that LM is zero - normally cases it should not be. */ |
| 1889 | if (!info->td_thr_tlsbase_p) |
| 1890 | throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR, |
| 1891 | _("TLS load module not found")); |
| 1892 | |
| 1893 | /* This code path handles the case of -static -pthread executables: |
| 1894 | https://sourceware.org/ml/libc-help/2014-03/msg00024.html |
| 1895 | For older GNU libc r_debug.r_map is NULL. For GNU libc after |
| 1896 | PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL. |
| 1897 | The constant number 1 depends on GNU __libc_setup_tls |
| 1898 | initialization of l_tls_modid to 1. */ |
| 1899 | err = info->td_thr_tlsbase_p (&thread_info->priv->th, |
| 1900 | 1, &address); |
| 1901 | address = (char *) address + offset; |
| 1902 | } |
| 1903 | |
| 1904 | #ifdef THREAD_DB_HAS_TD_NOTALLOC |
| 1905 | /* The memory hasn't been allocated, yet. */ |
| 1906 | if (err == TD_NOTALLOC) |
| 1907 | /* Now, if libthread_db provided the initialization image's |
| 1908 | address, we *could* try to build a non-lvalue value from |
| 1909 | the initialization image. */ |
| 1910 | throw_error (TLS_NOT_ALLOCATED_YET_ERROR, |
| 1911 | _("TLS not allocated yet")); |
| 1912 | #endif |
| 1913 | |
| 1914 | /* Something else went wrong. */ |
| 1915 | if (err != TD_OK) |
| 1916 | throw_error (TLS_GENERIC_ERROR, |
| 1917 | (("%s")), thread_db_err_str (err)); |
| 1918 | |
| 1919 | /* Cast assuming host == target. Joy. */ |
| 1920 | /* Do proper sign extension for the target. */ |
| 1921 | gdb_assert (exec_bfd); |
| 1922 | return (bfd_get_sign_extend_vma (exec_bfd) > 0 |
| 1923 | ? (CORE_ADDR) (intptr_t) address |
| 1924 | : (CORE_ADDR) (uintptr_t) address); |
| 1925 | } |
| 1926 | |
| 1927 | beneath = find_target_beneath (ops); |
| 1928 | return beneath->to_get_thread_local_address (beneath, ptid, lm, offset); |
| 1929 | } |
| 1930 | |
| 1931 | /* Implement the to_get_ada_task_ptid target method for this target. */ |
| 1932 | |
| 1933 | static ptid_t |
| 1934 | thread_db_get_ada_task_ptid (struct target_ops *self, long lwp, long thread) |
| 1935 | { |
| 1936 | /* NPTL uses a 1:1 model, so the LWP id suffices. */ |
| 1937 | return ptid_build (ptid_get_pid (inferior_ptid), lwp, 0); |
| 1938 | } |
| 1939 | |
| 1940 | static void |
| 1941 | thread_db_resume (struct target_ops *ops, |
| 1942 | ptid_t ptid, int step, enum gdb_signal signo) |
| 1943 | { |
| 1944 | struct target_ops *beneath = find_target_beneath (ops); |
| 1945 | struct thread_db_info *info; |
| 1946 | |
| 1947 | if (ptid_equal (ptid, minus_one_ptid)) |
| 1948 | info = get_thread_db_info (ptid_get_pid (inferior_ptid)); |
| 1949 | else |
| 1950 | info = get_thread_db_info (ptid_get_pid (ptid)); |
| 1951 | |
| 1952 | /* This workaround is only needed for child fork lwps stopped in a |
| 1953 | PTRACE_O_TRACEFORK event. When the inferior is resumed, the |
| 1954 | workaround can be disabled. */ |
| 1955 | if (info) |
| 1956 | info->need_stale_parent_threads_check = 0; |
| 1957 | |
| 1958 | beneath->to_resume (beneath, ptid, step, signo); |
| 1959 | } |
| 1960 | |
| 1961 | /* qsort helper function for info_auto_load_libthread_db, sort the |
| 1962 | thread_db_info pointers primarily by their FILENAME and secondarily by their |
| 1963 | PID, both in ascending order. */ |
| 1964 | |
| 1965 | static int |
| 1966 | info_auto_load_libthread_db_compare (const void *ap, const void *bp) |
| 1967 | { |
| 1968 | struct thread_db_info *a = *(struct thread_db_info **) ap; |
| 1969 | struct thread_db_info *b = *(struct thread_db_info **) bp; |
| 1970 | int retval; |
| 1971 | |
| 1972 | retval = strcmp (a->filename, b->filename); |
| 1973 | if (retval) |
| 1974 | return retval; |
| 1975 | |
| 1976 | return (a->pid > b->pid) - (a->pid - b->pid); |
| 1977 | } |
| 1978 | |
| 1979 | /* Implement 'info auto-load libthread-db'. */ |
| 1980 | |
| 1981 | static void |
| 1982 | info_auto_load_libthread_db (char *args, int from_tty) |
| 1983 | { |
| 1984 | struct ui_out *uiout = current_uiout; |
| 1985 | const char *cs = args ? args : ""; |
| 1986 | struct thread_db_info *info, **array; |
| 1987 | unsigned info_count, unique_filenames; |
| 1988 | size_t max_filename_len, max_pids_len, pids_len; |
| 1989 | struct cleanup *back_to; |
| 1990 | char *pids; |
| 1991 | int i; |
| 1992 | |
| 1993 | cs = skip_spaces_const (cs); |
| 1994 | if (*cs) |
| 1995 | error (_("'info auto-load libthread-db' does not accept any parameters")); |
| 1996 | |
| 1997 | info_count = 0; |
| 1998 | for (info = thread_db_list; info; info = info->next) |
| 1999 | if (info->filename != NULL) |
| 2000 | info_count++; |
| 2001 | |
| 2002 | array = XNEWVEC (struct thread_db_info *, info_count); |
| 2003 | back_to = make_cleanup (xfree, array); |
| 2004 | |
| 2005 | info_count = 0; |
| 2006 | for (info = thread_db_list; info; info = info->next) |
| 2007 | if (info->filename != NULL) |
| 2008 | array[info_count++] = info; |
| 2009 | |
| 2010 | /* Sort ARRAY by filenames and PIDs. */ |
| 2011 | |
| 2012 | qsort (array, info_count, sizeof (*array), |
| 2013 | info_auto_load_libthread_db_compare); |
| 2014 | |
| 2015 | /* Calculate the number of unique filenames (rows) and the maximum string |
| 2016 | length of PIDs list for the unique filenames (columns). */ |
| 2017 | |
| 2018 | unique_filenames = 0; |
| 2019 | max_filename_len = 0; |
| 2020 | max_pids_len = 0; |
| 2021 | pids_len = 0; |
| 2022 | for (i = 0; i < info_count; i++) |
| 2023 | { |
| 2024 | int pid = array[i]->pid; |
| 2025 | size_t this_pid_len; |
| 2026 | |
| 2027 | for (this_pid_len = 0; pid != 0; pid /= 10) |
| 2028 | this_pid_len++; |
| 2029 | |
| 2030 | if (i == 0 || strcmp (array[i - 1]->filename, array[i]->filename) != 0) |
| 2031 | { |
| 2032 | unique_filenames++; |
| 2033 | max_filename_len = max (max_filename_len, |
| 2034 | strlen (array[i]->filename)); |
| 2035 | |
| 2036 | if (i > 0) |
| 2037 | { |
| 2038 | pids_len -= strlen (", "); |
| 2039 | max_pids_len = max (max_pids_len, pids_len); |
| 2040 | } |
| 2041 | pids_len = 0; |
| 2042 | } |
| 2043 | pids_len += this_pid_len + strlen (", "); |
| 2044 | } |
| 2045 | if (i) |
| 2046 | { |
| 2047 | pids_len -= strlen (", "); |
| 2048 | max_pids_len = max (max_pids_len, pids_len); |
| 2049 | } |
| 2050 | |
| 2051 | /* Table header shifted right by preceding "libthread-db: " would not match |
| 2052 | its columns. */ |
| 2053 | if (info_count > 0 && args == auto_load_info_scripts_pattern_nl) |
| 2054 | ui_out_text (uiout, "\n"); |
| 2055 | |
| 2056 | make_cleanup_ui_out_table_begin_end (uiout, 2, unique_filenames, |
| 2057 | "LinuxThreadDbTable"); |
| 2058 | |
| 2059 | ui_out_table_header (uiout, max_filename_len, ui_left, "filename", |
| 2060 | "Filename"); |
| 2061 | ui_out_table_header (uiout, pids_len, ui_left, "PIDs", "Pids"); |
| 2062 | ui_out_table_body (uiout); |
| 2063 | |
| 2064 | pids = xmalloc (max_pids_len + 1); |
| 2065 | make_cleanup (xfree, pids); |
| 2066 | |
| 2067 | /* Note I is incremented inside the cycle, not at its end. */ |
| 2068 | for (i = 0; i < info_count;) |
| 2069 | { |
| 2070 | struct cleanup *chain = make_cleanup_ui_out_tuple_begin_end (uiout, NULL); |
| 2071 | char *pids_end; |
| 2072 | |
| 2073 | info = array[i]; |
| 2074 | ui_out_field_string (uiout, "filename", info->filename); |
| 2075 | pids_end = pids; |
| 2076 | |
| 2077 | while (i < info_count && strcmp (info->filename, array[i]->filename) == 0) |
| 2078 | { |
| 2079 | if (pids_end != pids) |
| 2080 | { |
| 2081 | *pids_end++ = ','; |
| 2082 | *pids_end++ = ' '; |
| 2083 | } |
| 2084 | pids_end += xsnprintf (pids_end, &pids[max_pids_len + 1] - pids_end, |
| 2085 | "%u", array[i]->pid); |
| 2086 | gdb_assert (pids_end < &pids[max_pids_len + 1]); |
| 2087 | |
| 2088 | i++; |
| 2089 | } |
| 2090 | *pids_end = '\0'; |
| 2091 | |
| 2092 | ui_out_field_string (uiout, "pids", pids); |
| 2093 | |
| 2094 | ui_out_text (uiout, "\n"); |
| 2095 | do_cleanups (chain); |
| 2096 | } |
| 2097 | |
| 2098 | do_cleanups (back_to); |
| 2099 | |
| 2100 | if (info_count == 0) |
| 2101 | ui_out_message (uiout, 0, _("No auto-loaded libthread-db.\n")); |
| 2102 | } |
| 2103 | |
| 2104 | static void |
| 2105 | init_thread_db_ops (void) |
| 2106 | { |
| 2107 | thread_db_ops.to_shortname = "multi-thread"; |
| 2108 | thread_db_ops.to_longname = "multi-threaded child process."; |
| 2109 | thread_db_ops.to_doc = "Threads and pthreads support."; |
| 2110 | thread_db_ops.to_detach = thread_db_detach; |
| 2111 | thread_db_ops.to_wait = thread_db_wait; |
| 2112 | thread_db_ops.to_resume = thread_db_resume; |
| 2113 | thread_db_ops.to_mourn_inferior = thread_db_mourn_inferior; |
| 2114 | thread_db_ops.to_update_thread_list = thread_db_update_thread_list; |
| 2115 | thread_db_ops.to_pid_to_str = thread_db_pid_to_str; |
| 2116 | thread_db_ops.to_stratum = thread_stratum; |
| 2117 | thread_db_ops.to_has_thread_control = tc_schedlock; |
| 2118 | thread_db_ops.to_get_thread_local_address |
| 2119 | = thread_db_get_thread_local_address; |
| 2120 | thread_db_ops.to_extra_thread_info = thread_db_extra_thread_info; |
| 2121 | thread_db_ops.to_get_ada_task_ptid = thread_db_get_ada_task_ptid; |
| 2122 | thread_db_ops.to_magic = OPS_MAGIC; |
| 2123 | |
| 2124 | complete_target_initialization (&thread_db_ops); |
| 2125 | } |
| 2126 | |
| 2127 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 2128 | extern initialize_file_ftype _initialize_thread_db; |
| 2129 | |
| 2130 | void |
| 2131 | _initialize_thread_db (void) |
| 2132 | { |
| 2133 | init_thread_db_ops (); |
| 2134 | |
| 2135 | /* Defer loading of libthread_db.so until inferior is running. |
| 2136 | This allows gdb to load correct libthread_db for a given |
| 2137 | executable -- there could be mutiple versions of glibc, |
| 2138 | compiled with LinuxThreads or NPTL, and until there is |
| 2139 | a running inferior, we can't tell which libthread_db is |
| 2140 | the correct one to load. */ |
| 2141 | |
| 2142 | libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH); |
| 2143 | |
| 2144 | add_setshow_optional_filename_cmd ("libthread-db-search-path", |
| 2145 | class_support, |
| 2146 | &libthread_db_search_path, _("\ |
| 2147 | Set search path for libthread_db."), _("\ |
| 2148 | Show the current search path or libthread_db."), _("\ |
| 2149 | This path is used to search for libthread_db to be loaded into \ |
| 2150 | gdb itself.\n\ |
| 2151 | Its value is a colon (':') separate list of directories to search.\n\ |
| 2152 | Setting the search path to an empty list resets it to its default value."), |
| 2153 | set_libthread_db_search_path, |
| 2154 | NULL, |
| 2155 | &setlist, &showlist); |
| 2156 | |
| 2157 | add_setshow_zuinteger_cmd ("libthread-db", class_maintenance, |
| 2158 | &libthread_db_debug, _("\ |
| 2159 | Set libthread-db debugging."), _("\ |
| 2160 | Show libthread-db debugging."), _("\ |
| 2161 | When non-zero, libthread-db debugging is enabled."), |
| 2162 | NULL, |
| 2163 | show_libthread_db_debug, |
| 2164 | &setdebuglist, &showdebuglist); |
| 2165 | |
| 2166 | add_setshow_boolean_cmd ("libthread-db", class_support, |
| 2167 | &auto_load_thread_db, _("\ |
| 2168 | Enable or disable auto-loading of inferior specific libthread_db."), _("\ |
| 2169 | Show whether auto-loading inferior specific libthread_db is enabled."), _("\ |
| 2170 | If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\ |
| 2171 | locations to load libthread_db compatible with the inferior.\n\ |
| 2172 | Standard system libthread_db still gets loaded even with this option off.\n\ |
| 2173 | This options has security implications for untrusted inferiors."), |
| 2174 | NULL, show_auto_load_thread_db, |
| 2175 | auto_load_set_cmdlist_get (), |
| 2176 | auto_load_show_cmdlist_get ()); |
| 2177 | |
| 2178 | add_cmd ("libthread-db", class_info, info_auto_load_libthread_db, |
| 2179 | _("Print the list of loaded inferior specific libthread_db.\n\ |
| 2180 | Usage: info auto-load libthread-db"), |
| 2181 | auto_load_info_cmdlist_get ()); |
| 2182 | |
| 2183 | /* Add ourselves to objfile event chain. */ |
| 2184 | observer_attach_new_objfile (thread_db_new_objfile); |
| 2185 | |
| 2186 | /* Add ourselves to inferior_created event chain. |
| 2187 | This is needed to handle debugging statically linked programs where |
| 2188 | the new_objfile observer won't get called for libpthread. */ |
| 2189 | observer_attach_inferior_created (thread_db_inferior_created); |
| 2190 | } |