| 1 | /* libthread_db assisted debugging support, generic parts. |
| 2 | |
| 3 | Copyright (C) 1999, 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009 |
| 4 | Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | |
| 23 | #include "gdb_assert.h" |
| 24 | #include <dlfcn.h> |
| 25 | #include "gdb_proc_service.h" |
| 26 | #include "gdb_thread_db.h" |
| 27 | |
| 28 | #include "bfd.h" |
| 29 | #include "command.h" |
| 30 | #include "exceptions.h" |
| 31 | #include "gdbcmd.h" |
| 32 | #include "gdbthread.h" |
| 33 | #include "inferior.h" |
| 34 | #include "symfile.h" |
| 35 | #include "objfiles.h" |
| 36 | #include "target.h" |
| 37 | #include "regcache.h" |
| 38 | #include "solib.h" |
| 39 | #include "solib-svr4.h" |
| 40 | #include "gdbcore.h" |
| 41 | #include "observer.h" |
| 42 | #include "linux-nat.h" |
| 43 | |
| 44 | #include <signal.h> |
| 45 | |
| 46 | #ifdef HAVE_GNU_LIBC_VERSION_H |
| 47 | #include <gnu/libc-version.h> |
| 48 | #endif |
| 49 | |
| 50 | /* GNU/Linux libthread_db support. |
| 51 | |
| 52 | libthread_db is a library, provided along with libpthread.so, which |
| 53 | exposes the internals of the thread library to a debugger. It |
| 54 | allows GDB to find existing threads, new threads as they are |
| 55 | created, thread IDs (usually, the result of pthread_self), and |
| 56 | thread-local variables. |
| 57 | |
| 58 | The libthread_db interface originates on Solaris, where it is |
| 59 | both more powerful and more complicated. This implementation |
| 60 | only works for LinuxThreads and NPTL, the two glibc threading |
| 61 | libraries. It assumes that each thread is permanently assigned |
| 62 | to a single light-weight process (LWP). |
| 63 | |
| 64 | libthread_db-specific information is stored in the "private" field |
| 65 | of struct thread_info. When the field is NULL we do not yet have |
| 66 | information about the new thread; this could be temporary (created, |
| 67 | but the thread library's data structures do not reflect it yet) |
| 68 | or permanent (created using clone instead of pthread_create). |
| 69 | |
| 70 | Process IDs managed by linux-thread-db.c match those used by |
| 71 | linux-nat.c: a common PID for all processes, an LWP ID for each |
| 72 | thread, and no TID. We save the TID in private. Keeping it out |
| 73 | of the ptid_t prevents thread IDs changing when libpthread is |
| 74 | loaded or unloaded. */ |
| 75 | |
| 76 | static char *libthread_db_search_path; |
| 77 | |
| 78 | /* If we're running on GNU/Linux, we must explicitly attach to any new |
| 79 | threads. */ |
| 80 | |
| 81 | /* This module's target vector. */ |
| 82 | static struct target_ops thread_db_ops; |
| 83 | |
| 84 | /* Non-zero if we have determined the signals used by the threads |
| 85 | library. */ |
| 86 | static int thread_signals; |
| 87 | static sigset_t thread_stop_set; |
| 88 | static sigset_t thread_print_set; |
| 89 | |
| 90 | struct thread_db_info |
| 91 | { |
| 92 | struct thread_db_info *next; |
| 93 | |
| 94 | /* Process id this object refers to. */ |
| 95 | int pid; |
| 96 | |
| 97 | /* Handle from dlopen for libthread_db.so. */ |
| 98 | void *handle; |
| 99 | |
| 100 | /* Structure that identifies the child process for the |
| 101 | <proc_service.h> interface. */ |
| 102 | struct ps_prochandle proc_handle; |
| 103 | |
| 104 | /* Connection to the libthread_db library. */ |
| 105 | td_thragent_t *thread_agent; |
| 106 | |
| 107 | /* True if we need to apply the workaround for glibc/BZ5983. When |
| 108 | we catch a PTRACE_O_TRACEFORK, and go query the child's thread |
| 109 | list, nptl_db returns the parent's threads in addition to the new |
| 110 | (single) child thread. If this flag is set, we do extra work to |
| 111 | be able to ignore such stale entries. */ |
| 112 | int need_stale_parent_threads_check; |
| 113 | |
| 114 | /* Location of the thread creation event breakpoint. The code at |
| 115 | this location in the child process will be called by the pthread |
| 116 | library whenever a new thread is created. By setting a special |
| 117 | breakpoint at this location, GDB can detect when a new thread is |
| 118 | created. We obtain this location via the td_ta_event_addr |
| 119 | call. */ |
| 120 | CORE_ADDR td_create_bp_addr; |
| 121 | |
| 122 | /* Location of the thread death event breakpoint. */ |
| 123 | CORE_ADDR td_death_bp_addr; |
| 124 | |
| 125 | /* Pointers to the libthread_db functions. */ |
| 126 | |
| 127 | td_err_e (*td_init_p) (void); |
| 128 | |
| 129 | td_err_e (*td_ta_new_p) (struct ps_prochandle * ps, |
| 130 | td_thragent_t **ta); |
| 131 | td_err_e (*td_ta_map_id2thr_p) (const td_thragent_t *ta, thread_t pt, |
| 132 | td_thrhandle_t *__th); |
| 133 | td_err_e (*td_ta_map_lwp2thr_p) (const td_thragent_t *ta, |
| 134 | lwpid_t lwpid, td_thrhandle_t *th); |
| 135 | td_err_e (*td_ta_thr_iter_p) (const td_thragent_t *ta, |
| 136 | td_thr_iter_f *callback, void *cbdata_p, |
| 137 | td_thr_state_e state, int ti_pri, |
| 138 | sigset_t *ti_sigmask_p, |
| 139 | unsigned int ti_user_flags); |
| 140 | td_err_e (*td_ta_event_addr_p) (const td_thragent_t *ta, |
| 141 | td_event_e event, td_notify_t *ptr); |
| 142 | td_err_e (*td_ta_set_event_p) (const td_thragent_t *ta, |
| 143 | td_thr_events_t *event); |
| 144 | td_err_e (*td_ta_event_getmsg_p) (const td_thragent_t *ta, |
| 145 | td_event_msg_t *msg); |
| 146 | |
| 147 | td_err_e (*td_thr_validate_p) (const td_thrhandle_t *th); |
| 148 | td_err_e (*td_thr_get_info_p) (const td_thrhandle_t *th, |
| 149 | td_thrinfo_t *infop); |
| 150 | td_err_e (*td_thr_event_enable_p) (const td_thrhandle_t *th, |
| 151 | int event); |
| 152 | |
| 153 | td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th, |
| 154 | void *map_address, |
| 155 | size_t offset, void **address); |
| 156 | }; |
| 157 | |
| 158 | /* List of known processes using thread_db, and the required |
| 159 | bookkeeping. */ |
| 160 | struct thread_db_info *thread_db_list; |
| 161 | |
| 162 | static void thread_db_find_new_threads_1 (ptid_t ptid); |
| 163 | |
| 164 | /* Add the current inferior to the list of processes using libpthread. |
| 165 | Return a pointer to the newly allocated object that was added to |
| 166 | THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing |
| 167 | LIBTHREAD_DB_SO. */ |
| 168 | |
| 169 | static struct thread_db_info * |
| 170 | add_thread_db_info (void *handle) |
| 171 | { |
| 172 | int pid; |
| 173 | struct thread_db_info *info; |
| 174 | |
| 175 | info = xcalloc (1, sizeof (*info)); |
| 176 | info->pid = ptid_get_pid (inferior_ptid); |
| 177 | info->handle = handle; |
| 178 | info->need_stale_parent_threads_check = 1; |
| 179 | |
| 180 | info->next = thread_db_list; |
| 181 | thread_db_list = info; |
| 182 | |
| 183 | return info; |
| 184 | } |
| 185 | |
| 186 | /* Return the thread_db_info object representing the bookkeeping |
| 187 | related to process PID, if any; NULL otherwise. */ |
| 188 | |
| 189 | static struct thread_db_info * |
| 190 | get_thread_db_info (int pid) |
| 191 | { |
| 192 | struct thread_db_info *info; |
| 193 | |
| 194 | for (info = thread_db_list; info; info = info->next) |
| 195 | if (pid == info->pid) |
| 196 | return info; |
| 197 | |
| 198 | return NULL; |
| 199 | } |
| 200 | |
| 201 | /* When PID has exited or has been detached, we no longer want to keep |
| 202 | track of it as using libpthread. Call this function to discard |
| 203 | thread_db related info related to PID. Note that this closes |
| 204 | LIBTHREAD_DB_SO's dlopen'ed handle. */ |
| 205 | |
| 206 | static void |
| 207 | delete_thread_db_info (int pid) |
| 208 | { |
| 209 | struct thread_db_info *info, *info_prev; |
| 210 | |
| 211 | info_prev = NULL; |
| 212 | |
| 213 | for (info = thread_db_list; info; info_prev = info, info = info->next) |
| 214 | if (pid == info->pid) |
| 215 | break; |
| 216 | |
| 217 | if (info == NULL) |
| 218 | return; |
| 219 | |
| 220 | if (info->handle != NULL) |
| 221 | dlclose (info->handle); |
| 222 | |
| 223 | if (info_prev) |
| 224 | info_prev->next = info->next; |
| 225 | else |
| 226 | thread_db_list = info->next; |
| 227 | |
| 228 | xfree (info); |
| 229 | } |
| 230 | |
| 231 | /* Prototypes for local functions. */ |
| 232 | static void attach_thread (ptid_t ptid, const td_thrhandle_t *th_p, |
| 233 | const td_thrinfo_t *ti_p); |
| 234 | static void detach_thread (ptid_t ptid); |
| 235 | \f |
| 236 | |
| 237 | /* Use "struct private_thread_info" to cache thread state. This is |
| 238 | a substantial optimization. */ |
| 239 | |
| 240 | struct private_thread_info |
| 241 | { |
| 242 | /* Flag set when we see a TD_DEATH event for this thread. */ |
| 243 | unsigned int dying:1; |
| 244 | |
| 245 | /* Cached thread state. */ |
| 246 | td_thrhandle_t th; |
| 247 | thread_t tid; |
| 248 | }; |
| 249 | \f |
| 250 | |
| 251 | static char * |
| 252 | thread_db_err_str (td_err_e err) |
| 253 | { |
| 254 | static char buf[64]; |
| 255 | |
| 256 | switch (err) |
| 257 | { |
| 258 | case TD_OK: |
| 259 | return "generic 'call succeeded'"; |
| 260 | case TD_ERR: |
| 261 | return "generic error"; |
| 262 | case TD_NOTHR: |
| 263 | return "no thread to satisfy query"; |
| 264 | case TD_NOSV: |
| 265 | return "no sync handle to satisfy query"; |
| 266 | case TD_NOLWP: |
| 267 | return "no LWP to satisfy query"; |
| 268 | case TD_BADPH: |
| 269 | return "invalid process handle"; |
| 270 | case TD_BADTH: |
| 271 | return "invalid thread handle"; |
| 272 | case TD_BADSH: |
| 273 | return "invalid synchronization handle"; |
| 274 | case TD_BADTA: |
| 275 | return "invalid thread agent"; |
| 276 | case TD_BADKEY: |
| 277 | return "invalid key"; |
| 278 | case TD_NOMSG: |
| 279 | return "no event message for getmsg"; |
| 280 | case TD_NOFPREGS: |
| 281 | return "FPU register set not available"; |
| 282 | case TD_NOLIBTHREAD: |
| 283 | return "application not linked with libthread"; |
| 284 | case TD_NOEVENT: |
| 285 | return "requested event is not supported"; |
| 286 | case TD_NOCAPAB: |
| 287 | return "capability not available"; |
| 288 | case TD_DBERR: |
| 289 | return "debugger service failed"; |
| 290 | case TD_NOAPLIC: |
| 291 | return "operation not applicable to"; |
| 292 | case TD_NOTSD: |
| 293 | return "no thread-specific data for this thread"; |
| 294 | case TD_MALLOC: |
| 295 | return "malloc failed"; |
| 296 | case TD_PARTIALREG: |
| 297 | return "only part of register set was written/read"; |
| 298 | case TD_NOXREGS: |
| 299 | return "X register set not available for this thread"; |
| 300 | #ifdef THREAD_DB_HAS_TD_NOTALLOC |
| 301 | case TD_NOTALLOC: |
| 302 | return "thread has not yet allocated TLS for given module"; |
| 303 | #endif |
| 304 | #ifdef THREAD_DB_HAS_TD_VERSION |
| 305 | case TD_VERSION: |
| 306 | return "versions of libpthread and libthread_db do not match"; |
| 307 | #endif |
| 308 | #ifdef THREAD_DB_HAS_TD_NOTLS |
| 309 | case TD_NOTLS: |
| 310 | return "there is no TLS segment in the given module"; |
| 311 | #endif |
| 312 | default: |
| 313 | snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err); |
| 314 | return buf; |
| 315 | } |
| 316 | } |
| 317 | \f |
| 318 | /* Return 1 if any threads have been registered. There may be none if |
| 319 | the threading library is not fully initialized yet. */ |
| 320 | |
| 321 | static int |
| 322 | have_threads_callback (struct thread_info *thread, void *args) |
| 323 | { |
| 324 | int pid = * (int *) args; |
| 325 | if (ptid_get_pid (thread->ptid) != pid) |
| 326 | return 0; |
| 327 | |
| 328 | return thread->private != NULL; |
| 329 | } |
| 330 | |
| 331 | static int |
| 332 | have_threads (ptid_t ptid) |
| 333 | { |
| 334 | int pid = ptid_get_pid (ptid); |
| 335 | |
| 336 | return iterate_over_threads (have_threads_callback, &pid) != NULL; |
| 337 | } |
| 338 | |
| 339 | struct thread_get_info_inout |
| 340 | { |
| 341 | struct thread_info *thread_info; |
| 342 | struct thread_db_info *thread_db_info; |
| 343 | }; |
| 344 | |
| 345 | /* A callback function for td_ta_thr_iter, which we use to map all |
| 346 | threads to LWPs. |
| 347 | |
| 348 | THP is a handle to the current thread; if INFOP is not NULL, the |
| 349 | struct thread_info associated with this thread is returned in |
| 350 | *INFOP. |
| 351 | |
| 352 | If the thread is a zombie, TD_THR_ZOMBIE is returned. Otherwise, |
| 353 | zero is returned to indicate success. */ |
| 354 | |
| 355 | static int |
| 356 | thread_get_info_callback (const td_thrhandle_t *thp, void *argp) |
| 357 | { |
| 358 | td_thrinfo_t ti; |
| 359 | td_err_e err; |
| 360 | ptid_t thread_ptid; |
| 361 | struct thread_get_info_inout *inout; |
| 362 | struct thread_db_info *info; |
| 363 | |
| 364 | inout = argp; |
| 365 | info = inout->thread_db_info; |
| 366 | |
| 367 | err = info->td_thr_get_info_p (thp, &ti); |
| 368 | if (err != TD_OK) |
| 369 | error (_("thread_get_info_callback: cannot get thread info: %s"), |
| 370 | thread_db_err_str (err)); |
| 371 | |
| 372 | /* Fill the cache. */ |
| 373 | thread_ptid = ptid_build (info->pid, ti.ti_lid, 0); |
| 374 | inout->thread_info = find_thread_pid (thread_ptid); |
| 375 | |
| 376 | /* In the case of a zombie thread, don't continue. We don't want to |
| 377 | attach to it thinking it is a new thread. */ |
| 378 | if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE) |
| 379 | return TD_THR_ZOMBIE; |
| 380 | |
| 381 | if (inout->thread_info == NULL) |
| 382 | { |
| 383 | /* New thread. Attach to it now (why wait?). */ |
| 384 | if (!have_threads (thread_ptid)) |
| 385 | thread_db_find_new_threads_1 (thread_ptid); |
| 386 | else |
| 387 | attach_thread (thread_ptid, thp, &ti); |
| 388 | inout->thread_info = find_thread_pid (thread_ptid); |
| 389 | gdb_assert (inout->thread_info != NULL); |
| 390 | } |
| 391 | |
| 392 | return 0; |
| 393 | } |
| 394 | \f |
| 395 | /* Convert between user-level thread ids and LWP ids. */ |
| 396 | |
| 397 | static ptid_t |
| 398 | thread_from_lwp (ptid_t ptid) |
| 399 | { |
| 400 | td_thrhandle_t th; |
| 401 | td_err_e err; |
| 402 | ptid_t thread_ptid; |
| 403 | struct thread_db_info *info; |
| 404 | struct thread_get_info_inout io = {0}; |
| 405 | |
| 406 | /* This ptid comes from linux-nat.c, which should always fill in the |
| 407 | LWP. */ |
| 408 | gdb_assert (GET_LWP (ptid) != 0); |
| 409 | |
| 410 | info = get_thread_db_info (GET_PID (ptid)); |
| 411 | |
| 412 | /* Access an lwp we know is stopped. */ |
| 413 | info->proc_handle.ptid = ptid; |
| 414 | err = info->td_ta_map_lwp2thr_p (info->thread_agent, GET_LWP (ptid), &th); |
| 415 | if (err != TD_OK) |
| 416 | error (_("Cannot find user-level thread for LWP %ld: %s"), |
| 417 | GET_LWP (ptid), thread_db_err_str (err)); |
| 418 | |
| 419 | /* Fetch the thread info. If we get back TD_THR_ZOMBIE, then the |
| 420 | event thread has already died. If another gdb interface has called |
| 421 | thread_alive() previously, the thread won't be found on the thread list |
| 422 | anymore. In that case, we don't want to process this ptid anymore |
| 423 | to avoid the possibility of later treating it as a newly |
| 424 | discovered thread id that we should add to the list. Thus, |
| 425 | we return a -1 ptid which is also how the thread list marks a |
| 426 | dead thread. */ |
| 427 | io.thread_db_info = info; |
| 428 | io.thread_info = NULL; |
| 429 | if (thread_get_info_callback (&th, &io) == TD_THR_ZOMBIE |
| 430 | && io.thread_info == NULL) |
| 431 | return minus_one_ptid; |
| 432 | |
| 433 | gdb_assert (ptid_get_tid (ptid) == 0); |
| 434 | return ptid; |
| 435 | } |
| 436 | \f |
| 437 | |
| 438 | /* Attach to lwp PTID, doing whatever else is required to have this |
| 439 | LWP under the debugger's control --- e.g., enabling event |
| 440 | reporting. Returns true on success. */ |
| 441 | int |
| 442 | thread_db_attach_lwp (ptid_t ptid) |
| 443 | { |
| 444 | td_thrhandle_t th; |
| 445 | td_thrinfo_t ti; |
| 446 | td_err_e err; |
| 447 | struct thread_db_info *info; |
| 448 | |
| 449 | info = get_thread_db_info (GET_PID (ptid)); |
| 450 | |
| 451 | if (info == NULL) |
| 452 | return 0; |
| 453 | |
| 454 | /* This ptid comes from linux-nat.c, which should always fill in the |
| 455 | LWP. */ |
| 456 | gdb_assert (GET_LWP (ptid) != 0); |
| 457 | |
| 458 | /* Access an lwp we know is stopped. */ |
| 459 | info->proc_handle.ptid = ptid; |
| 460 | |
| 461 | /* If we have only looked at the first thread before libpthread was |
| 462 | initialized, we may not know its thread ID yet. Make sure we do |
| 463 | before we add another thread to the list. */ |
| 464 | if (!have_threads (ptid)) |
| 465 | thread_db_find_new_threads_1 (ptid); |
| 466 | |
| 467 | err = info->td_ta_map_lwp2thr_p (info->thread_agent, GET_LWP (ptid), &th); |
| 468 | if (err != TD_OK) |
| 469 | /* Cannot find user-level thread. */ |
| 470 | return 0; |
| 471 | |
| 472 | err = info->td_thr_get_info_p (&th, &ti); |
| 473 | if (err != TD_OK) |
| 474 | { |
| 475 | warning (_("Cannot get thread info: %s"), thread_db_err_str (err)); |
| 476 | return 0; |
| 477 | } |
| 478 | |
| 479 | attach_thread (ptid, &th, &ti); |
| 480 | return 1; |
| 481 | } |
| 482 | |
| 483 | static void * |
| 484 | verbose_dlsym (void *handle, const char *name) |
| 485 | { |
| 486 | void *sym = dlsym (handle, name); |
| 487 | if (sym == NULL) |
| 488 | warning (_("Symbol \"%s\" not found in libthread_db: %s"), name, dlerror ()); |
| 489 | return sym; |
| 490 | } |
| 491 | |
| 492 | static td_err_e |
| 493 | enable_thread_event (int event, CORE_ADDR *bp) |
| 494 | { |
| 495 | td_notify_t notify; |
| 496 | td_err_e err; |
| 497 | struct thread_db_info *info; |
| 498 | |
| 499 | info = get_thread_db_info (GET_PID (inferior_ptid)); |
| 500 | |
| 501 | /* Access an lwp we know is stopped. */ |
| 502 | info->proc_handle.ptid = inferior_ptid; |
| 503 | |
| 504 | /* Get the breakpoint address for thread EVENT. */ |
| 505 | err = info->td_ta_event_addr_p (info->thread_agent, event, ¬ify); |
| 506 | if (err != TD_OK) |
| 507 | return err; |
| 508 | |
| 509 | /* Set up the breakpoint. */ |
| 510 | gdb_assert (exec_bfd); |
| 511 | (*bp) = (gdbarch_convert_from_func_ptr_addr |
| 512 | (current_gdbarch, |
| 513 | /* Do proper sign extension for the target. */ |
| 514 | (bfd_get_sign_extend_vma (exec_bfd) > 0 |
| 515 | ? (CORE_ADDR) (intptr_t) notify.u.bptaddr |
| 516 | : (CORE_ADDR) (uintptr_t) notify.u.bptaddr), |
| 517 | ¤t_target)); |
| 518 | create_thread_event_breakpoint ((*bp)); |
| 519 | |
| 520 | return TD_OK; |
| 521 | } |
| 522 | |
| 523 | static void |
| 524 | enable_thread_event_reporting (void) |
| 525 | { |
| 526 | td_thr_events_t events; |
| 527 | td_notify_t notify; |
| 528 | td_err_e err; |
| 529 | #ifdef HAVE_GNU_LIBC_VERSION_H |
| 530 | const char *libc_version; |
| 531 | int libc_major, libc_minor; |
| 532 | #endif |
| 533 | struct thread_db_info *info; |
| 534 | |
| 535 | info = get_thread_db_info (GET_PID (inferior_ptid)); |
| 536 | |
| 537 | /* We cannot use the thread event reporting facility if these |
| 538 | functions aren't available. */ |
| 539 | if (info->td_ta_event_addr_p == NULL |
| 540 | || info->td_ta_set_event_p == NULL |
| 541 | || info->td_ta_event_getmsg_p == NULL |
| 542 | || info->td_thr_event_enable_p == NULL) |
| 543 | return; |
| 544 | |
| 545 | /* Set the process wide mask saying which events we're interested in. */ |
| 546 | td_event_emptyset (&events); |
| 547 | td_event_addset (&events, TD_CREATE); |
| 548 | |
| 549 | #ifdef HAVE_GNU_LIBC_VERSION_H |
| 550 | /* The event reporting facility is broken for TD_DEATH events in |
| 551 | glibc 2.1.3, so don't enable it if we have glibc but a lower |
| 552 | version. */ |
| 553 | libc_version = gnu_get_libc_version (); |
| 554 | if (sscanf (libc_version, "%d.%d", &libc_major, &libc_minor) == 2 |
| 555 | && (libc_major > 2 || (libc_major == 2 && libc_minor > 1))) |
| 556 | #endif |
| 557 | td_event_addset (&events, TD_DEATH); |
| 558 | |
| 559 | err = info->td_ta_set_event_p (info->thread_agent, &events); |
| 560 | if (err != TD_OK) |
| 561 | { |
| 562 | warning (_("Unable to set global thread event mask: %s"), |
| 563 | thread_db_err_str (err)); |
| 564 | return; |
| 565 | } |
| 566 | |
| 567 | /* Delete previous thread event breakpoints, if any. */ |
| 568 | remove_thread_event_breakpoints (); |
| 569 | info->td_create_bp_addr = 0; |
| 570 | info->td_death_bp_addr = 0; |
| 571 | |
| 572 | /* Set up the thread creation event. */ |
| 573 | err = enable_thread_event (TD_CREATE, &info->td_create_bp_addr); |
| 574 | if (err != TD_OK) |
| 575 | { |
| 576 | warning (_("Unable to get location for thread creation breakpoint: %s"), |
| 577 | thread_db_err_str (err)); |
| 578 | return; |
| 579 | } |
| 580 | |
| 581 | /* Set up the thread death event. */ |
| 582 | err = enable_thread_event (TD_DEATH, &info->td_death_bp_addr); |
| 583 | if (err != TD_OK) |
| 584 | { |
| 585 | warning (_("Unable to get location for thread death breakpoint: %s"), |
| 586 | thread_db_err_str (err)); |
| 587 | return; |
| 588 | } |
| 589 | } |
| 590 | |
| 591 | /* Lookup a library in which given symbol resides. |
| 592 | Note: this is looking in GDB process, not in the inferior. |
| 593 | Returns library name, or NULL. */ |
| 594 | |
| 595 | static const char * |
| 596 | dladdr_to_soname (const void *addr) |
| 597 | { |
| 598 | Dl_info info; |
| 599 | |
| 600 | if (dladdr (addr, &info) != 0) |
| 601 | return info.dli_fname; |
| 602 | return NULL; |
| 603 | } |
| 604 | |
| 605 | /* Attempt to initialize dlopen()ed libthread_db, described by HANDLE. |
| 606 | Return 1 on success. |
| 607 | Failure could happen if libthread_db does not have symbols we expect, |
| 608 | or when it refuses to work with the current inferior (e.g. due to |
| 609 | version mismatch between libthread_db and libpthread). */ |
| 610 | |
| 611 | static int |
| 612 | try_thread_db_load_1 (struct thread_db_info *info) |
| 613 | { |
| 614 | td_err_e err; |
| 615 | |
| 616 | /* Initialize pointers to the dynamic library functions we will use. |
| 617 | Essential functions first. */ |
| 618 | |
| 619 | info->td_init_p = verbose_dlsym (info->handle, "td_init"); |
| 620 | if (info->td_init_p == NULL) |
| 621 | return 0; |
| 622 | |
| 623 | err = info->td_init_p (); |
| 624 | if (err != TD_OK) |
| 625 | { |
| 626 | warning (_("Cannot initialize libthread_db: %s"), thread_db_err_str (err)); |
| 627 | return 0; |
| 628 | } |
| 629 | |
| 630 | info->td_ta_new_p = verbose_dlsym (info->handle, "td_ta_new"); |
| 631 | if (info->td_ta_new_p == NULL) |
| 632 | return 0; |
| 633 | |
| 634 | /* Initialize the structure that identifies the child process. */ |
| 635 | info->proc_handle.ptid = inferior_ptid; |
| 636 | |
| 637 | /* Now attempt to open a connection to the thread library. */ |
| 638 | err = info->td_ta_new_p (&info->proc_handle, &info->thread_agent); |
| 639 | if (err != TD_OK) |
| 640 | { |
| 641 | if (info_verbose) |
| 642 | printf_unfiltered (_("td_ta_new failed: %s\n"), |
| 643 | thread_db_err_str (err)); |
| 644 | else |
| 645 | switch (err) |
| 646 | { |
| 647 | case TD_NOLIBTHREAD: |
| 648 | #ifdef THREAD_DB_HAS_TD_VERSION |
| 649 | case TD_VERSION: |
| 650 | #endif |
| 651 | /* The errors above are not unexpected and silently ignored: |
| 652 | they just mean we haven't found correct version of |
| 653 | libthread_db yet. */ |
| 654 | break; |
| 655 | default: |
| 656 | warning (_("td_ta_new failed: %s"), thread_db_err_str (err)); |
| 657 | } |
| 658 | return 0; |
| 659 | } |
| 660 | |
| 661 | info->td_ta_map_id2thr_p = verbose_dlsym (info->handle, "td_ta_map_id2thr"); |
| 662 | if (info->td_ta_map_id2thr_p == NULL) |
| 663 | return 0; |
| 664 | |
| 665 | info->td_ta_map_lwp2thr_p = verbose_dlsym (info->handle, "td_ta_map_lwp2thr"); |
| 666 | if (info->td_ta_map_lwp2thr_p == NULL) |
| 667 | return 0; |
| 668 | |
| 669 | info->td_ta_thr_iter_p = verbose_dlsym (info->handle, "td_ta_thr_iter"); |
| 670 | if (info->td_ta_thr_iter_p == NULL) |
| 671 | return 0; |
| 672 | |
| 673 | info->td_thr_validate_p = verbose_dlsym (info->handle, "td_thr_validate"); |
| 674 | if (info->td_thr_validate_p == NULL) |
| 675 | return 0; |
| 676 | |
| 677 | info->td_thr_get_info_p = verbose_dlsym (info->handle, "td_thr_get_info"); |
| 678 | if (info->td_thr_get_info_p == NULL) |
| 679 | return 0; |
| 680 | |
| 681 | /* These are not essential. */ |
| 682 | info->td_ta_event_addr_p = dlsym (info->handle, "td_ta_event_addr"); |
| 683 | info->td_ta_set_event_p = dlsym (info->handle, "td_ta_set_event"); |
| 684 | info->td_ta_event_getmsg_p = dlsym (info->handle, "td_ta_event_getmsg"); |
| 685 | info->td_thr_event_enable_p = dlsym (info->handle, "td_thr_event_enable"); |
| 686 | info->td_thr_tls_get_addr_p = dlsym (info->handle, "td_thr_tls_get_addr"); |
| 687 | |
| 688 | printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n")); |
| 689 | |
| 690 | if (info_verbose || *libthread_db_search_path) |
| 691 | { |
| 692 | const char *library; |
| 693 | |
| 694 | library = dladdr_to_soname (*info->td_ta_new_p); |
| 695 | if (library == NULL) |
| 696 | library = LIBTHREAD_DB_SO; |
| 697 | |
| 698 | printf_unfiltered (_("Using host libthread_db library \"%s\".\n"), |
| 699 | library); |
| 700 | } |
| 701 | |
| 702 | /* The thread library was detected. Activate the thread_db target |
| 703 | if this is the first process using it. */ |
| 704 | if (thread_db_list->next == NULL) |
| 705 | push_target (&thread_db_ops); |
| 706 | |
| 707 | enable_thread_event_reporting (); |
| 708 | thread_db_find_new_threads_1 (inferior_ptid); |
| 709 | return 1; |
| 710 | } |
| 711 | |
| 712 | /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute, |
| 713 | relative, or just LIBTHREAD_DB. */ |
| 714 | |
| 715 | static int |
| 716 | try_thread_db_load (const char *library) |
| 717 | { |
| 718 | void *handle; |
| 719 | struct thread_db_info *info; |
| 720 | |
| 721 | if (info_verbose) |
| 722 | printf_unfiltered (_("Trying host libthread_db library: %s.\n"), |
| 723 | library); |
| 724 | handle = dlopen (library, RTLD_NOW); |
| 725 | if (handle == NULL) |
| 726 | { |
| 727 | if (info_verbose) |
| 728 | printf_unfiltered (_("dlopen failed: %s.\n"), dlerror ()); |
| 729 | return 0; |
| 730 | } |
| 731 | |
| 732 | if (info_verbose && strchr (library, '/') == NULL) |
| 733 | { |
| 734 | void *td_init; |
| 735 | |
| 736 | td_init = dlsym (handle, "td_init"); |
| 737 | if (td_init != NULL) |
| 738 | { |
| 739 | const char *const libpath = dladdr_to_soname (td_init); |
| 740 | |
| 741 | if (libpath != NULL) |
| 742 | printf_unfiltered (_("Host %s resolved to: %s.\n"), |
| 743 | library, libpath); |
| 744 | } |
| 745 | } |
| 746 | |
| 747 | info = add_thread_db_info (handle); |
| 748 | |
| 749 | if (try_thread_db_load_1 (info)) |
| 750 | return 1; |
| 751 | |
| 752 | /* This library "refused" to work on current inferior. */ |
| 753 | delete_thread_db_info (GET_PID (inferior_ptid)); |
| 754 | return 0; |
| 755 | } |
| 756 | |
| 757 | |
| 758 | /* Search libthread_db_search_path for libthread_db which "agrees" |
| 759 | to work on current inferior. */ |
| 760 | |
| 761 | static int |
| 762 | thread_db_load_search (void) |
| 763 | { |
| 764 | char path[PATH_MAX]; |
| 765 | const char *search_path = libthread_db_search_path; |
| 766 | int rc = 0; |
| 767 | |
| 768 | while (*search_path) |
| 769 | { |
| 770 | const char *end = strchr (search_path, ':'); |
| 771 | if (end) |
| 772 | { |
| 773 | size_t len = end - search_path; |
| 774 | if (len + 1 + strlen (LIBTHREAD_DB_SO) + 1 > sizeof (path)) |
| 775 | { |
| 776 | char *cp = xmalloc (len + 1); |
| 777 | memcpy (cp, search_path, len); |
| 778 | cp[len] = '\0'; |
| 779 | warning (_("libthread_db_search_path component too long," |
| 780 | " ignored: %s."), cp); |
| 781 | xfree (cp); |
| 782 | search_path += len + 1; |
| 783 | continue; |
| 784 | } |
| 785 | memcpy (path, search_path, len); |
| 786 | path[len] = '\0'; |
| 787 | search_path += len + 1; |
| 788 | } |
| 789 | else |
| 790 | { |
| 791 | size_t len = strlen (search_path); |
| 792 | |
| 793 | if (len + 1 + strlen (LIBTHREAD_DB_SO) + 1 > sizeof (path)) |
| 794 | { |
| 795 | warning (_("libthread_db_search_path component too long," |
| 796 | " ignored: %s."), search_path); |
| 797 | break; |
| 798 | } |
| 799 | memcpy (path, search_path, len + 1); |
| 800 | search_path += len; |
| 801 | } |
| 802 | strcat (path, "/"); |
| 803 | strcat (path, LIBTHREAD_DB_SO); |
| 804 | if (try_thread_db_load (path)) |
| 805 | { |
| 806 | rc = 1; |
| 807 | break; |
| 808 | } |
| 809 | } |
| 810 | if (rc == 0) |
| 811 | rc = try_thread_db_load (LIBTHREAD_DB_SO); |
| 812 | return rc; |
| 813 | } |
| 814 | |
| 815 | /* Attempt to load and initialize libthread_db. |
| 816 | Return 1 on success. |
| 817 | */ |
| 818 | |
| 819 | static int |
| 820 | thread_db_load (void) |
| 821 | { |
| 822 | struct objfile *obj; |
| 823 | struct thread_db_info *info; |
| 824 | |
| 825 | info = get_thread_db_info (GET_PID (inferior_ptid)); |
| 826 | |
| 827 | if (info != NULL) |
| 828 | return 1; |
| 829 | |
| 830 | /* Don't attempt to use thread_db on targets which can not run |
| 831 | (executables not running yet, core files) for now. */ |
| 832 | if (!target_has_execution) |
| 833 | return 0; |
| 834 | |
| 835 | /* Don't attempt to use thread_db for remote targets. */ |
| 836 | if (!target_can_run (¤t_target)) |
| 837 | return 0; |
| 838 | |
| 839 | if (thread_db_load_search ()) |
| 840 | return 1; |
| 841 | |
| 842 | /* None of the libthread_db's on our search path, not the system default |
| 843 | ones worked. If the executable is dynamically linked against |
| 844 | libpthread, try loading libthread_db from the same directory. */ |
| 845 | |
| 846 | ALL_OBJFILES (obj) |
| 847 | if (libpthread_name_p (obj->name)) |
| 848 | { |
| 849 | char path[PATH_MAX], *cp; |
| 850 | |
| 851 | gdb_assert (strlen (obj->name) < sizeof (path)); |
| 852 | strcpy (path, obj->name); |
| 853 | cp = strrchr (path, '/'); |
| 854 | |
| 855 | if (cp == NULL) |
| 856 | { |
| 857 | warning (_("Expected absolute pathname for libpthread in the" |
| 858 | " inferior, but got %s."), path); |
| 859 | } |
| 860 | else if (cp + 1 + strlen (LIBTHREAD_DB_SO) + 1 > path + sizeof (path)) |
| 861 | { |
| 862 | warning (_("Unexpected: path to libpthread in the inferior is" |
| 863 | " too long: %s"), path); |
| 864 | } |
| 865 | else |
| 866 | { |
| 867 | strcpy (cp + 1, LIBTHREAD_DB_SO); |
| 868 | if (try_thread_db_load (path)) |
| 869 | return 1; |
| 870 | } |
| 871 | warning (_("Unable to find libthread_db matching inferior's thread" |
| 872 | " library, thread debugging will not be available.")); |
| 873 | return 0; |
| 874 | } |
| 875 | /* Either this executable isn't using libpthread at all, or it is |
| 876 | statically linked. Since we can't easily distinguish these two cases, |
| 877 | no warning is issued. */ |
| 878 | return 0; |
| 879 | } |
| 880 | |
| 881 | static void |
| 882 | disable_thread_event_reporting (void) |
| 883 | { |
| 884 | td_thr_events_t events; |
| 885 | struct thread_db_info *info; |
| 886 | |
| 887 | info = get_thread_db_info (GET_PID (inferior_ptid)); |
| 888 | |
| 889 | /* Set the process wide mask saying we aren't interested in any |
| 890 | events anymore. */ |
| 891 | td_event_emptyset (&events); |
| 892 | info->td_ta_set_event_p (info->thread_agent, &events); |
| 893 | |
| 894 | /* Delete thread event breakpoints, if any. */ |
| 895 | remove_thread_event_breakpoints (); |
| 896 | info->td_create_bp_addr = 0; |
| 897 | info->td_death_bp_addr = 0; |
| 898 | } |
| 899 | |
| 900 | static void |
| 901 | check_thread_signals (void) |
| 902 | { |
| 903 | #ifdef GET_THREAD_SIGNALS |
| 904 | if (!thread_signals) |
| 905 | { |
| 906 | sigset_t mask; |
| 907 | int i; |
| 908 | |
| 909 | GET_THREAD_SIGNALS (&mask); |
| 910 | sigemptyset (&thread_stop_set); |
| 911 | sigemptyset (&thread_print_set); |
| 912 | |
| 913 | for (i = 1; i < NSIG; i++) |
| 914 | { |
| 915 | if (sigismember (&mask, i)) |
| 916 | { |
| 917 | if (signal_stop_update (target_signal_from_host (i), 0)) |
| 918 | sigaddset (&thread_stop_set, i); |
| 919 | if (signal_print_update (target_signal_from_host (i), 0)) |
| 920 | sigaddset (&thread_print_set, i); |
| 921 | thread_signals = 1; |
| 922 | } |
| 923 | } |
| 924 | } |
| 925 | #endif |
| 926 | } |
| 927 | |
| 928 | /* Check whether thread_db is usable. This function is called when |
| 929 | an inferior is created (or otherwise acquired, e.g. attached to) |
| 930 | and when new shared libraries are loaded into a running process. */ |
| 931 | |
| 932 | void |
| 933 | check_for_thread_db (void) |
| 934 | { |
| 935 | td_err_e err; |
| 936 | static void *last_loaded; |
| 937 | |
| 938 | /* Do nothing if we couldn't load libthread_db.so.1. */ |
| 939 | if (!thread_db_load ()) |
| 940 | return; |
| 941 | } |
| 942 | |
| 943 | static void |
| 944 | thread_db_new_objfile (struct objfile *objfile) |
| 945 | { |
| 946 | /* This observer must always be called with inferior_ptid set |
| 947 | correctly. */ |
| 948 | |
| 949 | if (objfile != NULL) |
| 950 | check_for_thread_db (); |
| 951 | } |
| 952 | |
| 953 | /* Attach to a new thread. This function is called when we receive a |
| 954 | TD_CREATE event or when we iterate over all threads and find one |
| 955 | that wasn't already in our list. */ |
| 956 | |
| 957 | static void |
| 958 | attach_thread (ptid_t ptid, const td_thrhandle_t *th_p, |
| 959 | const td_thrinfo_t *ti_p) |
| 960 | { |
| 961 | struct private_thread_info *private; |
| 962 | struct thread_info *tp = NULL; |
| 963 | td_err_e err; |
| 964 | struct thread_db_info *info; |
| 965 | |
| 966 | /* If we're being called after a TD_CREATE event, we may already |
| 967 | know about this thread. There are two ways this can happen. We |
| 968 | may have iterated over all threads between the thread creation |
| 969 | and the TD_CREATE event, for instance when the user has issued |
| 970 | the `info threads' command before the SIGTRAP for hitting the |
| 971 | thread creation breakpoint was reported. Alternatively, the |
| 972 | thread may have exited and a new one been created with the same |
| 973 | thread ID. In the first case we don't need to do anything; in |
| 974 | the second case we should discard information about the dead |
| 975 | thread and attach to the new one. */ |
| 976 | if (in_thread_list (ptid)) |
| 977 | { |
| 978 | tp = find_thread_pid (ptid); |
| 979 | gdb_assert (tp != NULL); |
| 980 | |
| 981 | /* If tp->private is NULL, then GDB is already attached to this |
| 982 | thread, but we do not know anything about it. We can learn |
| 983 | about it here. This can only happen if we have some other |
| 984 | way besides libthread_db to notice new threads (i.e. |
| 985 | PTRACE_EVENT_CLONE); assume the same mechanism notices thread |
| 986 | exit, so this can not be a stale thread recreated with the |
| 987 | same ID. */ |
| 988 | if (tp->private != NULL) |
| 989 | { |
| 990 | if (!tp->private->dying) |
| 991 | return; |
| 992 | |
| 993 | delete_thread (ptid); |
| 994 | tp = NULL; |
| 995 | } |
| 996 | } |
| 997 | |
| 998 | check_thread_signals (); |
| 999 | |
| 1000 | if (ti_p->ti_state == TD_THR_UNKNOWN || ti_p->ti_state == TD_THR_ZOMBIE) |
| 1001 | return; /* A zombie thread -- do not attach. */ |
| 1002 | |
| 1003 | /* Under GNU/Linux, we have to attach to each and every thread. */ |
| 1004 | if (tp == NULL |
| 1005 | && lin_lwp_attach_lwp (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid))) < 0) |
| 1006 | return; |
| 1007 | |
| 1008 | /* Construct the thread's private data. */ |
| 1009 | private = xmalloc (sizeof (struct private_thread_info)); |
| 1010 | memset (private, 0, sizeof (struct private_thread_info)); |
| 1011 | |
| 1012 | /* A thread ID of zero may mean the thread library has not initialized |
| 1013 | yet. But we shouldn't even get here if that's the case. FIXME: |
| 1014 | if we change GDB to always have at least one thread in the thread |
| 1015 | list this will have to go somewhere else; maybe private == NULL |
| 1016 | until the thread_db target claims it. */ |
| 1017 | gdb_assert (ti_p->ti_tid != 0); |
| 1018 | private->th = *th_p; |
| 1019 | private->tid = ti_p->ti_tid; |
| 1020 | |
| 1021 | /* Add the thread to GDB's thread list. */ |
| 1022 | if (tp == NULL) |
| 1023 | tp = add_thread_with_info (ptid, private); |
| 1024 | else |
| 1025 | tp->private = private; |
| 1026 | |
| 1027 | info = get_thread_db_info (GET_PID (ptid)); |
| 1028 | |
| 1029 | /* Enable thread event reporting for this thread. */ |
| 1030 | err = info->td_thr_event_enable_p (th_p, 1); |
| 1031 | if (err != TD_OK) |
| 1032 | error (_("Cannot enable thread event reporting for %s: %s"), |
| 1033 | target_pid_to_str (ptid), thread_db_err_str (err)); |
| 1034 | } |
| 1035 | |
| 1036 | static void |
| 1037 | detach_thread (ptid_t ptid) |
| 1038 | { |
| 1039 | struct thread_info *thread_info; |
| 1040 | |
| 1041 | /* Don't delete the thread now, because it still reports as active |
| 1042 | until it has executed a few instructions after the event |
| 1043 | breakpoint - if we deleted it now, "info threads" would cause us |
| 1044 | to re-attach to it. Just mark it as having had a TD_DEATH |
| 1045 | event. This means that we won't delete it from our thread list |
| 1046 | until we notice that it's dead (via prune_threads), or until |
| 1047 | something re-uses its thread ID. We'll report the thread exit |
| 1048 | when the underlying LWP dies. */ |
| 1049 | thread_info = find_thread_pid (ptid); |
| 1050 | gdb_assert (thread_info != NULL && thread_info->private != NULL); |
| 1051 | thread_info->private->dying = 1; |
| 1052 | } |
| 1053 | |
| 1054 | static void |
| 1055 | thread_db_detach (struct target_ops *ops, char *args, int from_tty) |
| 1056 | { |
| 1057 | struct target_ops *target_beneath = find_target_beneath (ops); |
| 1058 | struct thread_db_info *info; |
| 1059 | |
| 1060 | info = get_thread_db_info (GET_PID (inferior_ptid)); |
| 1061 | |
| 1062 | if (info) |
| 1063 | { |
| 1064 | disable_thread_event_reporting (); |
| 1065 | |
| 1066 | /* Delete the old thread event breakpoints. Note that unlike |
| 1067 | when mourning, we can remove them here because there's still |
| 1068 | a live inferior to poke at. In any case, GDB will not try to |
| 1069 | insert anything in the inferior when removing a |
| 1070 | breakpoint. */ |
| 1071 | remove_thread_event_breakpoints (); |
| 1072 | |
| 1073 | delete_thread_db_info (GET_PID (inferior_ptid)); |
| 1074 | } |
| 1075 | |
| 1076 | target_beneath->to_detach (target_beneath, args, from_tty); |
| 1077 | |
| 1078 | /* NOTE: From this point on, inferior_ptid is null_ptid. */ |
| 1079 | |
| 1080 | /* If there are no more processes using libpthread, detach the |
| 1081 | thread_db target ops. */ |
| 1082 | if (!thread_db_list) |
| 1083 | unpush_target (&thread_db_ops); |
| 1084 | } |
| 1085 | |
| 1086 | /* Check if PID is currently stopped at the location of a thread event |
| 1087 | breakpoint location. If it is, read the event message and act upon |
| 1088 | the event. */ |
| 1089 | |
| 1090 | static void |
| 1091 | check_event (ptid_t ptid) |
| 1092 | { |
| 1093 | struct regcache *regcache = get_thread_regcache (ptid); |
| 1094 | struct gdbarch *gdbarch = get_regcache_arch (regcache); |
| 1095 | td_event_msg_t msg; |
| 1096 | td_thrinfo_t ti; |
| 1097 | td_err_e err; |
| 1098 | CORE_ADDR stop_pc; |
| 1099 | int loop = 0; |
| 1100 | struct thread_db_info *info; |
| 1101 | |
| 1102 | info = get_thread_db_info (GET_PID (ptid)); |
| 1103 | |
| 1104 | /* Bail out early if we're not at a thread event breakpoint. */ |
| 1105 | stop_pc = regcache_read_pc (regcache) |
| 1106 | - gdbarch_decr_pc_after_break (gdbarch); |
| 1107 | if (stop_pc != info->td_create_bp_addr |
| 1108 | && stop_pc != info->td_death_bp_addr) |
| 1109 | return; |
| 1110 | |
| 1111 | /* Access an lwp we know is stopped. */ |
| 1112 | info->proc_handle.ptid = ptid; |
| 1113 | |
| 1114 | /* If we have only looked at the first thread before libpthread was |
| 1115 | initialized, we may not know its thread ID yet. Make sure we do |
| 1116 | before we add another thread to the list. */ |
| 1117 | if (!have_threads (ptid)) |
| 1118 | thread_db_find_new_threads_1 (ptid); |
| 1119 | |
| 1120 | /* If we are at a create breakpoint, we do not know what new lwp |
| 1121 | was created and cannot specifically locate the event message for it. |
| 1122 | We have to call td_ta_event_getmsg() to get |
| 1123 | the latest message. Since we have no way of correlating whether |
| 1124 | the event message we get back corresponds to our breakpoint, we must |
| 1125 | loop and read all event messages, processing them appropriately. |
| 1126 | This guarantees we will process the correct message before continuing |
| 1127 | from the breakpoint. |
| 1128 | |
| 1129 | Currently, death events are not enabled. If they are enabled, |
| 1130 | the death event can use the td_thr_event_getmsg() interface to |
| 1131 | get the message specifically for that lwp and avoid looping |
| 1132 | below. */ |
| 1133 | |
| 1134 | loop = 1; |
| 1135 | |
| 1136 | do |
| 1137 | { |
| 1138 | err = info->td_ta_event_getmsg_p (info->thread_agent, &msg); |
| 1139 | if (err != TD_OK) |
| 1140 | { |
| 1141 | if (err == TD_NOMSG) |
| 1142 | return; |
| 1143 | |
| 1144 | error (_("Cannot get thread event message: %s"), |
| 1145 | thread_db_err_str (err)); |
| 1146 | } |
| 1147 | |
| 1148 | err = info->td_thr_get_info_p (msg.th_p, &ti); |
| 1149 | if (err != TD_OK) |
| 1150 | error (_("Cannot get thread info: %s"), thread_db_err_str (err)); |
| 1151 | |
| 1152 | ptid = ptid_build (GET_PID (ptid), ti.ti_lid, 0); |
| 1153 | |
| 1154 | switch (msg.event) |
| 1155 | { |
| 1156 | case TD_CREATE: |
| 1157 | /* Call attach_thread whether or not we already know about a |
| 1158 | thread with this thread ID. */ |
| 1159 | attach_thread (ptid, msg.th_p, &ti); |
| 1160 | |
| 1161 | break; |
| 1162 | |
| 1163 | case TD_DEATH: |
| 1164 | |
| 1165 | if (!in_thread_list (ptid)) |
| 1166 | error (_("Spurious thread death event.")); |
| 1167 | |
| 1168 | detach_thread (ptid); |
| 1169 | |
| 1170 | break; |
| 1171 | |
| 1172 | default: |
| 1173 | error (_("Spurious thread event.")); |
| 1174 | } |
| 1175 | } |
| 1176 | while (loop); |
| 1177 | } |
| 1178 | |
| 1179 | static ptid_t |
| 1180 | thread_db_wait (struct target_ops *ops, |
| 1181 | ptid_t ptid, struct target_waitstatus *ourstatus) |
| 1182 | { |
| 1183 | struct thread_db_info *info; |
| 1184 | struct target_ops *beneath = find_target_beneath (ops); |
| 1185 | |
| 1186 | ptid = beneath->to_wait (beneath, ptid, ourstatus); |
| 1187 | |
| 1188 | if (ourstatus->kind == TARGET_WAITKIND_IGNORE) |
| 1189 | return ptid; |
| 1190 | |
| 1191 | if (ourstatus->kind == TARGET_WAITKIND_EXITED |
| 1192 | || ourstatus->kind == TARGET_WAITKIND_SIGNALLED) |
| 1193 | return ptid; |
| 1194 | |
| 1195 | info = get_thread_db_info (GET_PID (ptid)); |
| 1196 | |
| 1197 | /* If this process isn't using thread_db, we're done. */ |
| 1198 | if (info == NULL) |
| 1199 | return ptid; |
| 1200 | |
| 1201 | if (ourstatus->kind == TARGET_WAITKIND_EXECD) |
| 1202 | { |
| 1203 | /* Breakpoints have already been marked non-inserted by the |
| 1204 | layer below. We're safe in knowing that removing them will |
| 1205 | not write the shadows of the old image into the new |
| 1206 | image. */ |
| 1207 | remove_thread_event_breakpoints (); |
| 1208 | |
| 1209 | /* New image, it may or may not end up using thread_db. Assume |
| 1210 | not unless we find otherwise. */ |
| 1211 | delete_thread_db_info (GET_PID (ptid)); |
| 1212 | if (!thread_db_list) |
| 1213 | unpush_target (&thread_db_ops); |
| 1214 | |
| 1215 | return ptid; |
| 1216 | } |
| 1217 | |
| 1218 | /* If we do not know about the main thread yet, this would be a good time to |
| 1219 | find it. */ |
| 1220 | if (ourstatus->kind == TARGET_WAITKIND_STOPPED && !have_threads (ptid)) |
| 1221 | thread_db_find_new_threads_1 (ptid); |
| 1222 | |
| 1223 | if (ourstatus->kind == TARGET_WAITKIND_STOPPED |
| 1224 | && ourstatus->value.sig == TARGET_SIGNAL_TRAP) |
| 1225 | /* Check for a thread event. */ |
| 1226 | check_event (ptid); |
| 1227 | |
| 1228 | if (have_threads (ptid)) |
| 1229 | { |
| 1230 | /* Change ptids back into the higher level PID + TID format. If |
| 1231 | the thread is dead and no longer on the thread list, we will |
| 1232 | get back a dead ptid. This can occur if the thread death |
| 1233 | event gets postponed by other simultaneous events. In such a |
| 1234 | case, we want to just ignore the event and continue on. */ |
| 1235 | |
| 1236 | ptid = thread_from_lwp (ptid); |
| 1237 | if (GET_PID (ptid) == -1) |
| 1238 | ourstatus->kind = TARGET_WAITKIND_SPURIOUS; |
| 1239 | } |
| 1240 | |
| 1241 | return ptid; |
| 1242 | } |
| 1243 | |
| 1244 | static void |
| 1245 | thread_db_mourn_inferior (struct target_ops *ops) |
| 1246 | { |
| 1247 | struct target_ops *target_beneath = find_target_beneath (ops); |
| 1248 | |
| 1249 | delete_thread_db_info (GET_PID (inferior_ptid)); |
| 1250 | |
| 1251 | /* Delete the old thread event breakpoints. Mark breakpoints out, |
| 1252 | so that we don't try to un-insert them. */ |
| 1253 | mark_breakpoints_out (); |
| 1254 | remove_thread_event_breakpoints (); |
| 1255 | |
| 1256 | target_beneath->to_mourn_inferior (target_beneath); |
| 1257 | |
| 1258 | /* Detach thread_db target ops. */ |
| 1259 | if (!thread_db_list) |
| 1260 | unpush_target (ops); |
| 1261 | } |
| 1262 | |
| 1263 | static int |
| 1264 | find_new_threads_callback (const td_thrhandle_t *th_p, void *data) |
| 1265 | { |
| 1266 | td_thrinfo_t ti; |
| 1267 | td_err_e err; |
| 1268 | ptid_t ptid; |
| 1269 | struct thread_info *tp; |
| 1270 | struct thread_db_info *info = data; |
| 1271 | |
| 1272 | err = info->td_thr_get_info_p (th_p, &ti); |
| 1273 | if (err != TD_OK) |
| 1274 | error (_("find_new_threads_callback: cannot get thread info: %s"), |
| 1275 | thread_db_err_str (err)); |
| 1276 | |
| 1277 | if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE) |
| 1278 | return 0; /* A zombie -- ignore. */ |
| 1279 | |
| 1280 | if (ti.ti_tid == 0) |
| 1281 | { |
| 1282 | /* A thread ID of zero means that this is the main thread, but |
| 1283 | glibc has not yet initialized thread-local storage and the |
| 1284 | pthread library. We do not know what the thread's TID will |
| 1285 | be yet. Just enable event reporting and otherwise ignore |
| 1286 | it. */ |
| 1287 | |
| 1288 | /* In that case, we're not stopped in a fork syscall and don't |
| 1289 | need this glibc bug workaround. */ |
| 1290 | info->need_stale_parent_threads_check = 0; |
| 1291 | |
| 1292 | err = info->td_thr_event_enable_p (th_p, 1); |
| 1293 | if (err != TD_OK) |
| 1294 | error (_("Cannot enable thread event reporting for LWP %d: %s"), |
| 1295 | (int) ti.ti_lid, thread_db_err_str (err)); |
| 1296 | |
| 1297 | return 0; |
| 1298 | } |
| 1299 | |
| 1300 | /* Ignore stale parent threads, caused by glibc/BZ5983. This is a |
| 1301 | bit expensive, as it needs to open /proc/pid/status, so try to |
| 1302 | avoid doing the work if we know we don't have to. */ |
| 1303 | if (info->need_stale_parent_threads_check) |
| 1304 | { |
| 1305 | int tgid = linux_proc_get_tgid (ti.ti_lid); |
| 1306 | if (tgid != -1 && tgid != info->pid) |
| 1307 | return 0; |
| 1308 | } |
| 1309 | |
| 1310 | ptid = ptid_build (info->pid, ti.ti_lid, 0); |
| 1311 | tp = find_thread_pid (ptid); |
| 1312 | if (tp == NULL || tp->private == NULL) |
| 1313 | attach_thread (ptid, th_p, &ti); |
| 1314 | |
| 1315 | return 0; |
| 1316 | } |
| 1317 | |
| 1318 | /* Search for new threads, accessing memory through stopped thread |
| 1319 | PTID. */ |
| 1320 | |
| 1321 | static void |
| 1322 | thread_db_find_new_threads_1 (ptid_t ptid) |
| 1323 | { |
| 1324 | td_err_e err; |
| 1325 | struct lwp_info *lp; |
| 1326 | struct thread_db_info *info; |
| 1327 | int pid = ptid_get_pid (ptid); |
| 1328 | |
| 1329 | /* In linux, we can only read memory through a stopped lwp. */ |
| 1330 | ALL_LWPS (lp, ptid) |
| 1331 | if (lp->stopped && ptid_get_pid (lp->ptid) == pid) |
| 1332 | break; |
| 1333 | |
| 1334 | if (!lp) |
| 1335 | /* There is no stopped thread. Bail out. */ |
| 1336 | return; |
| 1337 | |
| 1338 | info = get_thread_db_info (GET_PID (ptid)); |
| 1339 | |
| 1340 | /* Access an lwp we know is stopped. */ |
| 1341 | info->proc_handle.ptid = ptid; |
| 1342 | /* Iterate over all user-space threads to discover new threads. */ |
| 1343 | err = info->td_ta_thr_iter_p (info->thread_agent, find_new_threads_callback, |
| 1344 | info, TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY, |
| 1345 | TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS); |
| 1346 | if (err != TD_OK) |
| 1347 | error (_("Cannot find new threads: %s"), thread_db_err_str (err)); |
| 1348 | } |
| 1349 | |
| 1350 | static void |
| 1351 | thread_db_find_new_threads (struct target_ops *ops) |
| 1352 | { |
| 1353 | struct thread_db_info *info; |
| 1354 | |
| 1355 | info = get_thread_db_info (GET_PID (inferior_ptid)); |
| 1356 | |
| 1357 | if (info == NULL) |
| 1358 | return; |
| 1359 | |
| 1360 | thread_db_find_new_threads_1 (inferior_ptid); |
| 1361 | } |
| 1362 | |
| 1363 | static char * |
| 1364 | thread_db_pid_to_str (struct target_ops *ops, ptid_t ptid) |
| 1365 | { |
| 1366 | struct thread_info *thread_info = find_thread_pid (ptid); |
| 1367 | struct target_ops *beneath; |
| 1368 | |
| 1369 | if (thread_info != NULL && thread_info->private != NULL) |
| 1370 | { |
| 1371 | static char buf[64]; |
| 1372 | thread_t tid; |
| 1373 | |
| 1374 | tid = thread_info->private->tid; |
| 1375 | snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)", |
| 1376 | tid, GET_LWP (ptid)); |
| 1377 | |
| 1378 | return buf; |
| 1379 | } |
| 1380 | |
| 1381 | beneath = find_target_beneath (ops); |
| 1382 | if (beneath->to_pid_to_str (beneath, ptid)) |
| 1383 | return beneath->to_pid_to_str (beneath, ptid); |
| 1384 | |
| 1385 | return normal_pid_to_str (ptid); |
| 1386 | } |
| 1387 | |
| 1388 | /* Return a string describing the state of the thread specified by |
| 1389 | INFO. */ |
| 1390 | |
| 1391 | static char * |
| 1392 | thread_db_extra_thread_info (struct thread_info *info) |
| 1393 | { |
| 1394 | if (info->private == NULL) |
| 1395 | return NULL; |
| 1396 | |
| 1397 | if (info->private->dying) |
| 1398 | return "Exiting"; |
| 1399 | |
| 1400 | return NULL; |
| 1401 | } |
| 1402 | |
| 1403 | /* Get the address of the thread local variable in load module LM which |
| 1404 | is stored at OFFSET within the thread local storage for thread PTID. */ |
| 1405 | |
| 1406 | static CORE_ADDR |
| 1407 | thread_db_get_thread_local_address (struct target_ops *ops, |
| 1408 | ptid_t ptid, |
| 1409 | CORE_ADDR lm, |
| 1410 | CORE_ADDR offset) |
| 1411 | { |
| 1412 | struct thread_info *thread_info; |
| 1413 | struct target_ops *beneath; |
| 1414 | |
| 1415 | /* If we have not discovered any threads yet, check now. */ |
| 1416 | if (!have_threads (ptid)) |
| 1417 | thread_db_find_new_threads_1 (ptid); |
| 1418 | |
| 1419 | /* Find the matching thread. */ |
| 1420 | thread_info = find_thread_pid (ptid); |
| 1421 | |
| 1422 | if (thread_info != NULL && thread_info->private != NULL) |
| 1423 | { |
| 1424 | td_err_e err; |
| 1425 | void *address; |
| 1426 | struct thread_db_info *info; |
| 1427 | |
| 1428 | info = get_thread_db_info (GET_PID (ptid)); |
| 1429 | |
| 1430 | /* glibc doesn't provide the needed interface. */ |
| 1431 | if (!info->td_thr_tls_get_addr_p) |
| 1432 | throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR, |
| 1433 | _("No TLS library support")); |
| 1434 | |
| 1435 | /* Caller should have verified that lm != 0. */ |
| 1436 | gdb_assert (lm != 0); |
| 1437 | |
| 1438 | /* Finally, get the address of the variable. */ |
| 1439 | err = info->td_thr_tls_get_addr_p (&thread_info->private->th, |
| 1440 | (void *)(size_t) lm, |
| 1441 | offset, &address); |
| 1442 | |
| 1443 | #ifdef THREAD_DB_HAS_TD_NOTALLOC |
| 1444 | /* The memory hasn't been allocated, yet. */ |
| 1445 | if (err == TD_NOTALLOC) |
| 1446 | /* Now, if libthread_db provided the initialization image's |
| 1447 | address, we *could* try to build a non-lvalue value from |
| 1448 | the initialization image. */ |
| 1449 | throw_error (TLS_NOT_ALLOCATED_YET_ERROR, |
| 1450 | _("TLS not allocated yet")); |
| 1451 | #endif |
| 1452 | |
| 1453 | /* Something else went wrong. */ |
| 1454 | if (err != TD_OK) |
| 1455 | throw_error (TLS_GENERIC_ERROR, |
| 1456 | (("%s")), thread_db_err_str (err)); |
| 1457 | |
| 1458 | /* Cast assuming host == target. Joy. */ |
| 1459 | /* Do proper sign extension for the target. */ |
| 1460 | gdb_assert (exec_bfd); |
| 1461 | return (bfd_get_sign_extend_vma (exec_bfd) > 0 |
| 1462 | ? (CORE_ADDR) (intptr_t) address |
| 1463 | : (CORE_ADDR) (uintptr_t) address); |
| 1464 | } |
| 1465 | |
| 1466 | beneath = find_target_beneath (ops); |
| 1467 | if (beneath->to_get_thread_local_address) |
| 1468 | return beneath->to_get_thread_local_address (beneath, ptid, lm, offset); |
| 1469 | else |
| 1470 | throw_error (TLS_GENERIC_ERROR, |
| 1471 | _("TLS not supported on this target")); |
| 1472 | } |
| 1473 | |
| 1474 | /* Callback routine used to find a thread based on the TID part of |
| 1475 | its PTID. */ |
| 1476 | |
| 1477 | static int |
| 1478 | thread_db_find_thread_from_tid (struct thread_info *thread, void *data) |
| 1479 | { |
| 1480 | long *tid = (long *) data; |
| 1481 | |
| 1482 | if (thread->private->tid == *tid) |
| 1483 | return 1; |
| 1484 | |
| 1485 | return 0; |
| 1486 | } |
| 1487 | |
| 1488 | /* Implement the to_get_ada_task_ptid target method for this target. */ |
| 1489 | |
| 1490 | static ptid_t |
| 1491 | thread_db_get_ada_task_ptid (long lwp, long thread) |
| 1492 | { |
| 1493 | struct thread_info *thread_info; |
| 1494 | |
| 1495 | thread_db_find_new_threads_1 (inferior_ptid); |
| 1496 | thread_info = iterate_over_threads (thread_db_find_thread_from_tid, &thread); |
| 1497 | |
| 1498 | gdb_assert (thread_info != NULL); |
| 1499 | |
| 1500 | return (thread_info->ptid); |
| 1501 | } |
| 1502 | |
| 1503 | static void |
| 1504 | thread_db_resume (struct target_ops *ops, |
| 1505 | ptid_t ptid, int step, enum target_signal signo) |
| 1506 | { |
| 1507 | struct target_ops *beneath = find_target_beneath (ops); |
| 1508 | struct thread_db_info *info; |
| 1509 | |
| 1510 | if (ptid_equal (ptid, minus_one_ptid)) |
| 1511 | info = get_thread_db_info (GET_PID (inferior_ptid)); |
| 1512 | else |
| 1513 | info = get_thread_db_info (GET_PID (ptid)); |
| 1514 | |
| 1515 | /* This workaround is only needed for child fork lwps stopped in a |
| 1516 | PTRACE_O_TRACEFORK event. When the inferior is resumed, the |
| 1517 | workaround can be disabled. */ |
| 1518 | if (info) |
| 1519 | info->need_stale_parent_threads_check = 0; |
| 1520 | |
| 1521 | beneath->to_resume (beneath, ptid, step, signo); |
| 1522 | } |
| 1523 | |
| 1524 | static void |
| 1525 | init_thread_db_ops (void) |
| 1526 | { |
| 1527 | thread_db_ops.to_shortname = "multi-thread"; |
| 1528 | thread_db_ops.to_longname = "multi-threaded child process."; |
| 1529 | thread_db_ops.to_doc = "Threads and pthreads support."; |
| 1530 | thread_db_ops.to_detach = thread_db_detach; |
| 1531 | thread_db_ops.to_wait = thread_db_wait; |
| 1532 | thread_db_ops.to_resume = thread_db_resume; |
| 1533 | thread_db_ops.to_mourn_inferior = thread_db_mourn_inferior; |
| 1534 | thread_db_ops.to_find_new_threads = thread_db_find_new_threads; |
| 1535 | thread_db_ops.to_pid_to_str = thread_db_pid_to_str; |
| 1536 | thread_db_ops.to_stratum = thread_stratum; |
| 1537 | thread_db_ops.to_has_thread_control = tc_schedlock; |
| 1538 | thread_db_ops.to_get_thread_local_address |
| 1539 | = thread_db_get_thread_local_address; |
| 1540 | thread_db_ops.to_extra_thread_info = thread_db_extra_thread_info; |
| 1541 | thread_db_ops.to_get_ada_task_ptid = thread_db_get_ada_task_ptid; |
| 1542 | thread_db_ops.to_magic = OPS_MAGIC; |
| 1543 | } |
| 1544 | |
| 1545 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 1546 | extern initialize_file_ftype _initialize_thread_db; |
| 1547 | |
| 1548 | void |
| 1549 | _initialize_thread_db (void) |
| 1550 | { |
| 1551 | init_thread_db_ops (); |
| 1552 | add_target (&thread_db_ops); |
| 1553 | |
| 1554 | /* Defer loading of libthread_db.so until inferior is running. |
| 1555 | This allows gdb to load correct libthread_db for a given |
| 1556 | executable -- there could be mutiple versions of glibc, |
| 1557 | compiled with LinuxThreads or NPTL, and until there is |
| 1558 | a running inferior, we can't tell which libthread_db is |
| 1559 | the correct one to load. */ |
| 1560 | |
| 1561 | libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH); |
| 1562 | |
| 1563 | add_setshow_optional_filename_cmd ("libthread-db-search-path", |
| 1564 | class_support, |
| 1565 | &libthread_db_search_path, _("\ |
| 1566 | Set search path for libthread_db."), _("\ |
| 1567 | Show the current search path or libthread_db."), _("\ |
| 1568 | This path is used to search for libthread_db to be loaded into \ |
| 1569 | gdb itself."), |
| 1570 | NULL, |
| 1571 | NULL, |
| 1572 | &setlist, &showlist); |
| 1573 | /* Add ourselves to objfile event chain. */ |
| 1574 | observer_attach_new_objfile (thread_db_new_objfile); |
| 1575 | } |