1 /* libthread_db assisted debugging support, generic parts.
3 Copyright (C) 1999-2001, 2003-2012 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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/>. */
22 #include "gdb_assert.h"
24 #include "gdb_proc_service.h"
25 #include "gdb_thread_db.h"
29 #include "exceptions.h"
31 #include "gdbthread.h"
38 #include "solib-svr4.h"
41 #include "linux-nat.h"
42 #include "linux-procfs.h"
43 #include "linux-osdata.h"
47 #ifdef HAVE_GNU_LIBC_VERSION_H
48 #include <gnu/libc-version.h>
51 /* GNU/Linux libthread_db support.
53 libthread_db is a library, provided along with libpthread.so, which
54 exposes the internals of the thread library to a debugger. It
55 allows GDB to find existing threads, new threads as they are
56 created, thread IDs (usually, the result of pthread_self), and
57 thread-local variables.
59 The libthread_db interface originates on Solaris, where it is
60 both more powerful and more complicated. This implementation
61 only works for LinuxThreads and NPTL, the two glibc threading
62 libraries. It assumes that each thread is permanently assigned
63 to a single light-weight process (LWP).
65 libthread_db-specific information is stored in the "private" field
66 of struct thread_info. When the field is NULL we do not yet have
67 information about the new thread; this could be temporary (created,
68 but the thread library's data structures do not reflect it yet)
69 or permanent (created using clone instead of pthread_create).
71 Process IDs managed by linux-thread-db.c match those used by
72 linux-nat.c: a common PID for all processes, an LWP ID for each
73 thread, and no TID. We save the TID in private. Keeping it out
74 of the ptid_t prevents thread IDs changing when libpthread is
75 loaded or unloaded. */
77 static char *libthread_db_search_path;
80 set_libthread_db_search_path (char *ignored, int from_tty,
81 struct cmd_list_element *c)
83 if (*libthread_db_search_path == '\0')
85 xfree (libthread_db_search_path);
86 libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
90 /* If non-zero, print details of libthread_db processing. */
92 static int libthread_db_debug;
95 show_libthread_db_debug (struct ui_file *file, int from_tty,
96 struct cmd_list_element *c, const char *value)
98 fprintf_filtered (file, _("libthread-db debugging is %s.\n"), value);
101 /* If we're running on GNU/Linux, we must explicitly attach to any new
104 /* This module's target vector. */
105 static struct target_ops thread_db_ops;
107 /* Non-zero if we have determined the signals used by the threads
109 static int thread_signals;
110 static sigset_t thread_stop_set;
111 static sigset_t thread_print_set;
113 struct thread_db_info
115 struct thread_db_info *next;
117 /* Process id this object refers to. */
120 /* Handle from dlopen for libthread_db.so. */
123 /* Structure that identifies the child process for the
124 <proc_service.h> interface. */
125 struct ps_prochandle proc_handle;
127 /* Connection to the libthread_db library. */
128 td_thragent_t *thread_agent;
130 /* True if we need to apply the workaround for glibc/BZ5983. When
131 we catch a PTRACE_O_TRACEFORK, and go query the child's thread
132 list, nptl_db returns the parent's threads in addition to the new
133 (single) child thread. If this flag is set, we do extra work to
134 be able to ignore such stale entries. */
135 int need_stale_parent_threads_check;
137 /* Location of the thread creation event breakpoint. The code at
138 this location in the child process will be called by the pthread
139 library whenever a new thread is created. By setting a special
140 breakpoint at this location, GDB can detect when a new thread is
141 created. We obtain this location via the td_ta_event_addr
143 CORE_ADDR td_create_bp_addr;
145 /* Location of the thread death event breakpoint. */
146 CORE_ADDR td_death_bp_addr;
148 /* Pointers to the libthread_db functions. */
150 td_err_e (*td_init_p) (void);
152 td_err_e (*td_ta_new_p) (struct ps_prochandle * ps,
154 td_err_e (*td_ta_map_id2thr_p) (const td_thragent_t *ta, thread_t pt,
155 td_thrhandle_t *__th);
156 td_err_e (*td_ta_map_lwp2thr_p) (const td_thragent_t *ta,
157 lwpid_t lwpid, td_thrhandle_t *th);
158 td_err_e (*td_ta_thr_iter_p) (const td_thragent_t *ta,
159 td_thr_iter_f *callback, void *cbdata_p,
160 td_thr_state_e state, int ti_pri,
161 sigset_t *ti_sigmask_p,
162 unsigned int ti_user_flags);
163 td_err_e (*td_ta_event_addr_p) (const td_thragent_t *ta,
164 td_event_e event, td_notify_t *ptr);
165 td_err_e (*td_ta_set_event_p) (const td_thragent_t *ta,
166 td_thr_events_t *event);
167 td_err_e (*td_ta_clear_event_p) (const td_thragent_t *ta,
168 td_thr_events_t *event);
169 td_err_e (*td_ta_event_getmsg_p) (const td_thragent_t *ta,
170 td_event_msg_t *msg);
172 td_err_e (*td_thr_validate_p) (const td_thrhandle_t *th);
173 td_err_e (*td_thr_get_info_p) (const td_thrhandle_t *th,
174 td_thrinfo_t *infop);
175 td_err_e (*td_thr_event_enable_p) (const td_thrhandle_t *th,
178 td_err_e (*td_thr_tls_get_addr_p) (const td_thrhandle_t *th,
179 psaddr_t map_address,
180 size_t offset, psaddr_t *address);
183 /* List of known processes using thread_db, and the required
185 struct thread_db_info *thread_db_list;
187 static void thread_db_find_new_threads_1 (ptid_t ptid);
188 static void thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new);
190 /* Add the current inferior to the list of processes using libpthread.
191 Return a pointer to the newly allocated object that was added to
192 THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
195 static struct thread_db_info *
196 add_thread_db_info (void *handle)
198 struct thread_db_info *info;
200 info = xcalloc (1, sizeof (*info));
201 info->pid = ptid_get_pid (inferior_ptid);
202 info->handle = handle;
204 /* The workaround works by reading from /proc/pid/status, so it is
205 disabled for core files. */
206 if (target_has_execution)
207 info->need_stale_parent_threads_check = 1;
209 info->next = thread_db_list;
210 thread_db_list = info;
215 /* Return the thread_db_info object representing the bookkeeping
216 related to process PID, if any; NULL otherwise. */
218 static struct thread_db_info *
219 get_thread_db_info (int pid)
221 struct thread_db_info *info;
223 for (info = thread_db_list; info; info = info->next)
224 if (pid == info->pid)
230 /* When PID has exited or has been detached, we no longer want to keep
231 track of it as using libpthread. Call this function to discard
232 thread_db related info related to PID. Note that this closes
233 LIBTHREAD_DB_SO's dlopen'ed handle. */
236 delete_thread_db_info (int pid)
238 struct thread_db_info *info, *info_prev;
242 for (info = thread_db_list; info; info_prev = info, info = info->next)
243 if (pid == info->pid)
249 if (info->handle != NULL)
250 dlclose (info->handle);
253 info_prev->next = info->next;
255 thread_db_list = info->next;
260 /* Prototypes for local functions. */
261 static int attach_thread (ptid_t ptid, const td_thrhandle_t *th_p,
262 const td_thrinfo_t *ti_p);
263 static void detach_thread (ptid_t ptid);
266 /* Use "struct private_thread_info" to cache thread state. This is
267 a substantial optimization. */
269 struct private_thread_info
271 /* Flag set when we see a TD_DEATH event for this thread. */
272 unsigned int dying:1;
274 /* Cached thread state. */
281 thread_db_err_str (td_err_e err)
288 return "generic 'call succeeded'";
290 return "generic error";
292 return "no thread to satisfy query";
294 return "no sync handle to satisfy query";
296 return "no LWP to satisfy query";
298 return "invalid process handle";
300 return "invalid thread handle";
302 return "invalid synchronization handle";
304 return "invalid thread agent";
306 return "invalid key";
308 return "no event message for getmsg";
310 return "FPU register set not available";
312 return "application not linked with libthread";
314 return "requested event is not supported";
316 return "capability not available";
318 return "debugger service failed";
320 return "operation not applicable to";
322 return "no thread-specific data for this thread";
324 return "malloc failed";
326 return "only part of register set was written/read";
328 return "X register set not available for this thread";
329 #ifdef THREAD_DB_HAS_TD_NOTALLOC
331 return "thread has not yet allocated TLS for given module";
333 #ifdef THREAD_DB_HAS_TD_VERSION
335 return "versions of libpthread and libthread_db do not match";
337 #ifdef THREAD_DB_HAS_TD_NOTLS
339 return "there is no TLS segment in the given module";
342 snprintf (buf, sizeof (buf), "unknown thread_db error '%d'", err);
347 /* Return 1 if any threads have been registered. There may be none if
348 the threading library is not fully initialized yet. */
351 have_threads_callback (struct thread_info *thread, void *args)
353 int pid = * (int *) args;
355 if (ptid_get_pid (thread->ptid) != pid)
358 return thread->private != NULL;
362 have_threads (ptid_t ptid)
364 int pid = ptid_get_pid (ptid);
366 return iterate_over_threads (have_threads_callback, &pid) != NULL;
369 struct thread_get_info_inout
371 struct thread_info *thread_info;
372 struct thread_db_info *thread_db_info;
375 /* A callback function for td_ta_thr_iter, which we use to map all
378 THP is a handle to the current thread; if INFOP is not NULL, the
379 struct thread_info associated with this thread is returned in
382 If the thread is a zombie, TD_THR_ZOMBIE is returned. Otherwise,
383 zero is returned to indicate success. */
386 thread_get_info_callback (const td_thrhandle_t *thp, void *argp)
391 struct thread_get_info_inout *inout;
392 struct thread_db_info *info;
395 info = inout->thread_db_info;
397 err = info->td_thr_get_info_p (thp, &ti);
399 error (_("thread_get_info_callback: cannot get thread info: %s"),
400 thread_db_err_str (err));
402 /* Fill the cache. */
403 thread_ptid = ptid_build (info->pid, ti.ti_lid, 0);
404 inout->thread_info = find_thread_ptid (thread_ptid);
406 /* In the case of a zombie thread, don't continue. We don't want to
407 attach to it thinking it is a new thread. */
408 if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
409 return TD_THR_ZOMBIE;
411 if (inout->thread_info == NULL)
413 /* New thread. Attach to it now (why wait?). */
414 if (!have_threads (thread_ptid))
415 thread_db_find_new_threads_1 (thread_ptid);
417 attach_thread (thread_ptid, thp, &ti);
418 inout->thread_info = find_thread_ptid (thread_ptid);
419 gdb_assert (inout->thread_info != NULL);
425 /* Convert between user-level thread ids and LWP ids. */
428 thread_from_lwp (ptid_t ptid)
432 struct thread_db_info *info;
433 struct thread_get_info_inout io = {0};
435 /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
438 /* This ptid comes from linux-nat.c, which should always fill in the
440 gdb_assert (GET_LWP (ptid) != 0);
442 info = get_thread_db_info (GET_PID (ptid));
444 /* Access an lwp we know is stopped. */
445 info->proc_handle.ptid = ptid;
446 err = info->td_ta_map_lwp2thr_p (info->thread_agent, GET_LWP (ptid), &th);
448 error (_("Cannot find user-level thread for LWP %ld: %s"),
449 GET_LWP (ptid), thread_db_err_str (err));
451 /* Fetch the thread info. If we get back TD_THR_ZOMBIE, then the
452 event thread has already died. If another gdb interface has called
453 thread_alive() previously, the thread won't be found on the thread list
454 anymore. In that case, we don't want to process this ptid anymore
455 to avoid the possibility of later treating it as a newly
456 discovered thread id that we should add to the list. Thus,
457 we return a -1 ptid which is also how the thread list marks a
459 io.thread_db_info = info;
460 io.thread_info = NULL;
461 if (thread_get_info_callback (&th, &io) == TD_THR_ZOMBIE
462 && io.thread_info == NULL)
463 return minus_one_ptid;
465 gdb_assert (ptid_get_tid (ptid) == 0);
470 /* Attach to lwp PTID, doing whatever else is required to have this
471 LWP under the debugger's control --- e.g., enabling event
472 reporting. Returns true on success. */
474 thread_db_attach_lwp (ptid_t ptid)
479 struct thread_db_info *info;
481 info = get_thread_db_info (GET_PID (ptid));
486 /* This ptid comes from linux-nat.c, which should always fill in the
488 gdb_assert (GET_LWP (ptid) != 0);
490 /* Access an lwp we know is stopped. */
491 info->proc_handle.ptid = ptid;
493 /* If we have only looked at the first thread before libpthread was
494 initialized, we may not know its thread ID yet. Make sure we do
495 before we add another thread to the list. */
496 if (!have_threads (ptid))
497 thread_db_find_new_threads_1 (ptid);
499 err = info->td_ta_map_lwp2thr_p (info->thread_agent, GET_LWP (ptid), &th);
501 /* Cannot find user-level thread. */
504 err = info->td_thr_get_info_p (&th, &ti);
507 warning (_("Cannot get thread info: %s"), thread_db_err_str (err));
511 attach_thread (ptid, &th, &ti);
516 verbose_dlsym (void *handle, const char *name)
518 void *sym = dlsym (handle, name);
520 warning (_("Symbol \"%s\" not found in libthread_db: %s"),
526 enable_thread_event (int event, CORE_ADDR *bp)
530 struct thread_db_info *info;
532 info = get_thread_db_info (GET_PID (inferior_ptid));
534 /* Access an lwp we know is stopped. */
535 info->proc_handle.ptid = inferior_ptid;
537 /* Get the breakpoint address for thread EVENT. */
538 err = info->td_ta_event_addr_p (info->thread_agent, event, ¬ify);
542 /* Set up the breakpoint. */
543 gdb_assert (exec_bfd);
544 (*bp) = (gdbarch_convert_from_func_ptr_addr
546 /* Do proper sign extension for the target. */
547 (bfd_get_sign_extend_vma (exec_bfd) > 0
548 ? (CORE_ADDR) (intptr_t) notify.u.bptaddr
549 : (CORE_ADDR) (uintptr_t) notify.u.bptaddr),
551 create_thread_event_breakpoint (target_gdbarch, *bp);
557 enable_thread_event_reporting (void)
559 td_thr_events_t events;
561 #ifdef HAVE_GNU_LIBC_VERSION_H
562 const char *libc_version;
563 int libc_major, libc_minor;
565 struct thread_db_info *info;
567 info = get_thread_db_info (GET_PID (inferior_ptid));
569 /* We cannot use the thread event reporting facility if these
570 functions aren't available. */
571 if (info->td_ta_event_addr_p == NULL
572 || info->td_ta_set_event_p == NULL
573 || info->td_ta_event_getmsg_p == NULL
574 || info->td_thr_event_enable_p == NULL)
577 /* Set the process wide mask saying which events we're interested in. */
578 td_event_emptyset (&events);
579 td_event_addset (&events, TD_CREATE);
581 #ifdef HAVE_GNU_LIBC_VERSION_H
582 /* The event reporting facility is broken for TD_DEATH events in
583 glibc 2.1.3, so don't enable it if we have glibc but a lower
585 libc_version = gnu_get_libc_version ();
586 if (sscanf (libc_version, "%d.%d", &libc_major, &libc_minor) == 2
587 && (libc_major > 2 || (libc_major == 2 && libc_minor > 1)))
589 td_event_addset (&events, TD_DEATH);
591 err = info->td_ta_set_event_p (info->thread_agent, &events);
594 warning (_("Unable to set global thread event mask: %s"),
595 thread_db_err_str (err));
599 /* Delete previous thread event breakpoints, if any. */
600 remove_thread_event_breakpoints ();
601 info->td_create_bp_addr = 0;
602 info->td_death_bp_addr = 0;
604 /* Set up the thread creation event. */
605 err = enable_thread_event (TD_CREATE, &info->td_create_bp_addr);
608 warning (_("Unable to get location for thread creation breakpoint: %s"),
609 thread_db_err_str (err));
613 /* Set up the thread death event. */
614 err = enable_thread_event (TD_DEATH, &info->td_death_bp_addr);
617 warning (_("Unable to get location for thread death breakpoint: %s"),
618 thread_db_err_str (err));
623 /* Same as thread_db_find_new_threads_1, but silently ignore errors. */
626 thread_db_find_new_threads_silently (ptid_t ptid)
628 volatile struct gdb_exception except;
630 TRY_CATCH (except, RETURN_MASK_ERROR)
632 thread_db_find_new_threads_2 (ptid, 1);
635 if (except.reason < 0 && libthread_db_debug)
637 exception_fprintf (gdb_stderr, except,
638 "Warning: thread_db_find_new_threads_silently: ");
642 /* Lookup a library in which given symbol resides.
643 Note: this is looking in GDB process, not in the inferior.
644 Returns library name, or NULL. */
647 dladdr_to_soname (const void *addr)
651 if (dladdr (addr, &info) != 0)
652 return info.dli_fname;
656 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
658 Failure could happen if libthread_db does not have symbols we expect,
659 or when it refuses to work with the current inferior (e.g. due to
660 version mismatch between libthread_db and libpthread). */
663 try_thread_db_load_1 (struct thread_db_info *info)
667 /* Initialize pointers to the dynamic library functions we will use.
668 Essential functions first. */
670 info->td_init_p = verbose_dlsym (info->handle, "td_init");
671 if (info->td_init_p == NULL)
674 err = info->td_init_p ();
677 warning (_("Cannot initialize libthread_db: %s"),
678 thread_db_err_str (err));
682 info->td_ta_new_p = verbose_dlsym (info->handle, "td_ta_new");
683 if (info->td_ta_new_p == NULL)
686 /* Initialize the structure that identifies the child process. */
687 info->proc_handle.ptid = inferior_ptid;
689 /* Now attempt to open a connection to the thread library. */
690 err = info->td_ta_new_p (&info->proc_handle, &info->thread_agent);
693 if (libthread_db_debug)
694 printf_unfiltered (_("td_ta_new failed: %s\n"),
695 thread_db_err_str (err));
700 #ifdef THREAD_DB_HAS_TD_VERSION
703 /* The errors above are not unexpected and silently ignored:
704 they just mean we haven't found correct version of
708 warning (_("td_ta_new failed: %s"), thread_db_err_str (err));
713 info->td_ta_map_id2thr_p = verbose_dlsym (info->handle, "td_ta_map_id2thr");
714 if (info->td_ta_map_id2thr_p == NULL)
717 info->td_ta_map_lwp2thr_p = verbose_dlsym (info->handle,
718 "td_ta_map_lwp2thr");
719 if (info->td_ta_map_lwp2thr_p == NULL)
722 info->td_ta_thr_iter_p = verbose_dlsym (info->handle, "td_ta_thr_iter");
723 if (info->td_ta_thr_iter_p == NULL)
726 info->td_thr_validate_p = verbose_dlsym (info->handle, "td_thr_validate");
727 if (info->td_thr_validate_p == NULL)
730 info->td_thr_get_info_p = verbose_dlsym (info->handle, "td_thr_get_info");
731 if (info->td_thr_get_info_p == NULL)
734 /* These are not essential. */
735 info->td_ta_event_addr_p = dlsym (info->handle, "td_ta_event_addr");
736 info->td_ta_set_event_p = dlsym (info->handle, "td_ta_set_event");
737 info->td_ta_clear_event_p = dlsym (info->handle, "td_ta_clear_event");
738 info->td_ta_event_getmsg_p = dlsym (info->handle, "td_ta_event_getmsg");
739 info->td_thr_event_enable_p = dlsym (info->handle, "td_thr_event_enable");
740 info->td_thr_tls_get_addr_p = dlsym (info->handle, "td_thr_tls_get_addr");
742 printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
744 if (libthread_db_debug || *libthread_db_search_path)
748 library = dladdr_to_soname (*info->td_ta_new_p);
750 library = LIBTHREAD_DB_SO;
752 printf_unfiltered (_("Using host libthread_db library \"%s\".\n"),
756 /* The thread library was detected. Activate the thread_db target
757 if this is the first process using it. */
758 if (thread_db_list->next == NULL)
759 push_target (&thread_db_ops);
761 /* Enable event reporting, but not when debugging a core file. */
762 if (target_has_execution)
763 enable_thread_event_reporting ();
765 /* There appears to be a bug in glibc-2.3.6: calls to td_thr_get_info fail
766 with TD_ERR for statically linked executables if td_thr_get_info is
767 called before glibc has initialized itself. Silently ignore such
768 errors, and let gdb enumerate threads again later. */
769 thread_db_find_new_threads_silently (inferior_ptid);
774 /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
775 relative, or just LIBTHREAD_DB. */
778 try_thread_db_load (const char *library)
781 struct thread_db_info *info;
783 if (libthread_db_debug)
784 printf_unfiltered (_("Trying host libthread_db library: %s.\n"),
786 handle = dlopen (library, RTLD_NOW);
789 if (libthread_db_debug)
790 printf_unfiltered (_("dlopen failed: %s.\n"), dlerror ());
794 if (libthread_db_debug && strchr (library, '/') == NULL)
798 td_init = dlsym (handle, "td_init");
801 const char *const libpath = dladdr_to_soname (td_init);
804 printf_unfiltered (_("Host %s resolved to: %s.\n"),
809 info = add_thread_db_info (handle);
811 if (try_thread_db_load_1 (info))
814 /* This library "refused" to work on current inferior. */
815 delete_thread_db_info (GET_PID (inferior_ptid));
819 /* Subroutine of try_thread_db_load_from_pdir to simplify it.
820 Try loading libthread_db from the same directory as OBJ.
821 The result is true for success. */
824 try_thread_db_load_from_pdir_1 (struct objfile *obj)
826 struct cleanup *cleanup;
830 if (obj->name[0] != '/')
832 warning (_("Expected absolute pathname for libpthread in the"
833 " inferior, but got %s."), obj->name);
837 path = xmalloc (strlen (obj->name) + 1 + strlen (LIBTHREAD_DB_SO) + 1);
838 cleanup = make_cleanup (xfree, path);
840 strcpy (path, obj->name);
841 cp = strrchr (path, '/');
842 /* This should at minimum hit the first character. */
843 gdb_assert (cp != NULL);
844 strcpy (cp + 1, LIBTHREAD_DB_SO);
845 result = try_thread_db_load (path);
847 do_cleanups (cleanup);
851 /* Handle $pdir in libthread-db-search-path.
852 Look for libthread_db in the directory of libpthread.
853 The result is true for success. */
856 try_thread_db_load_from_pdir (void)
861 if (libpthread_name_p (obj->name))
863 if (try_thread_db_load_from_pdir_1 (obj))
866 /* We may have found the separate-debug-info version of
867 libpthread, and it may live in a directory without a matching
869 if (obj->separate_debug_objfile_backlink != NULL)
870 return try_thread_db_load_from_pdir_1 (obj->separate_debug_objfile_backlink);
878 /* Handle $sdir in libthread-db-search-path.
879 Look for libthread_db in the system dirs, or wherever a plain
880 dlopen(file_without_path) will look.
881 The result is true for success. */
884 try_thread_db_load_from_sdir (void)
886 return try_thread_db_load (LIBTHREAD_DB_SO);
889 /* Try to load libthread_db from directory DIR of length DIR_LEN.
890 The result is true for success. */
893 try_thread_db_load_from_dir (const char *dir, size_t dir_len)
895 struct cleanup *cleanup;
899 path = xmalloc (dir_len + 1 + strlen (LIBTHREAD_DB_SO) + 1);
900 cleanup = make_cleanup (xfree, path);
902 memcpy (path, dir, dir_len);
904 strcpy (path + dir_len + 1, LIBTHREAD_DB_SO);
905 result = try_thread_db_load (path);
907 do_cleanups (cleanup);
911 /* Search libthread_db_search_path for libthread_db which "agrees"
912 to work on current inferior.
913 The result is true for success. */
916 thread_db_load_search (void)
918 const char *search_path = libthread_db_search_path;
923 const char *end = strchr (search_path, ':');
924 const char *this_dir = search_path;
929 this_dir_len = end - search_path;
930 search_path += this_dir_len + 1;
934 this_dir_len = strlen (this_dir);
935 search_path += this_dir_len;
938 if (this_dir_len == sizeof ("$pdir") - 1
939 && strncmp (this_dir, "$pdir", this_dir_len) == 0)
941 if (try_thread_db_load_from_pdir ())
947 else if (this_dir_len == sizeof ("$sdir") - 1
948 && strncmp (this_dir, "$sdir", this_dir_len) == 0)
950 if (try_thread_db_load_from_sdir ())
958 if (try_thread_db_load_from_dir (this_dir, this_dir_len))
966 if (libthread_db_debug)
967 printf_unfiltered (_("thread_db_load_search returning %d\n"), rc);
971 /* Return non-zero if the inferior has a libpthread. */
974 has_libpthread (void)
979 if (libpthread_name_p (obj->name))
985 /* Attempt to load and initialize libthread_db.
986 Return 1 on success. */
989 thread_db_load (void)
991 struct thread_db_info *info;
993 info = get_thread_db_info (GET_PID (inferior_ptid));
998 /* Don't attempt to use thread_db on executables not running
1000 if (!target_has_registers)
1003 /* Don't attempt to use thread_db for remote targets. */
1004 if (!(target_can_run (¤t_target) || core_bfd))
1007 if (thread_db_load_search ())
1010 /* We couldn't find a libthread_db.
1011 If the inferior has a libpthread warn the user. */
1012 if (has_libpthread ())
1014 warning (_("Unable to find libthread_db matching inferior's thread"
1015 " library, thread debugging will not be available."));
1019 /* Either this executable isn't using libpthread at all, or it is
1020 statically linked. Since we can't easily distinguish these two cases,
1021 no warning is issued. */
1026 disable_thread_event_reporting (struct thread_db_info *info)
1028 if (info->td_ta_clear_event_p != NULL)
1030 td_thr_events_t events;
1032 /* Set the process wide mask saying we aren't interested in any
1034 td_event_fillset (&events);
1035 info->td_ta_clear_event_p (info->thread_agent, &events);
1038 info->td_create_bp_addr = 0;
1039 info->td_death_bp_addr = 0;
1043 check_thread_signals (void)
1045 if (!thread_signals)
1050 lin_thread_get_thread_signals (&mask);
1051 sigemptyset (&thread_stop_set);
1052 sigemptyset (&thread_print_set);
1054 for (i = 1; i < NSIG; i++)
1056 if (sigismember (&mask, i))
1058 if (signal_stop_update (target_signal_from_host (i), 0))
1059 sigaddset (&thread_stop_set, i);
1060 if (signal_print_update (target_signal_from_host (i), 0))
1061 sigaddset (&thread_print_set, i);
1068 /* Check whether thread_db is usable. This function is called when
1069 an inferior is created (or otherwise acquired, e.g. attached to)
1070 and when new shared libraries are loaded into a running process. */
1073 check_for_thread_db (void)
1075 /* Do nothing if we couldn't load libthread_db.so.1. */
1076 if (!thread_db_load ())
1080 /* This function is called via the new_objfile observer. */
1083 thread_db_new_objfile (struct objfile *objfile)
1085 /* This observer must always be called with inferior_ptid set
1089 /* Only check for thread_db if we loaded libpthread,
1090 or if this is the main symbol file.
1091 We need to check OBJF_MAINLINE to handle the case of debugging
1092 a statically linked executable AND the symbol file is specified AFTER
1093 the exec file is loaded (e.g., gdb -c core ; file foo).
1094 For dynamically linked executables, libpthread can be near the end
1095 of the list of shared libraries to load, and in an app of several
1096 thousand shared libraries, this can otherwise be painful. */
1097 && ((objfile->flags & OBJF_MAINLINE) != 0
1098 || libpthread_name_p (objfile->name)))
1099 check_for_thread_db ();
1102 /* This function is called via the inferior_created observer.
1103 This handles the case of debugging statically linked executables. */
1106 thread_db_inferior_created (struct target_ops *target, int from_tty)
1108 check_for_thread_db ();
1111 /* Attach to a new thread. This function is called when we receive a
1112 TD_CREATE event or when we iterate over all threads and find one
1113 that wasn't already in our list. Returns true on success. */
1116 attach_thread (ptid_t ptid, const td_thrhandle_t *th_p,
1117 const td_thrinfo_t *ti_p)
1119 struct private_thread_info *private;
1120 struct thread_info *tp;
1122 struct thread_db_info *info;
1124 /* If we're being called after a TD_CREATE event, we may already
1125 know about this thread. There are two ways this can happen. We
1126 may have iterated over all threads between the thread creation
1127 and the TD_CREATE event, for instance when the user has issued
1128 the `info threads' command before the SIGTRAP for hitting the
1129 thread creation breakpoint was reported. Alternatively, the
1130 thread may have exited and a new one been created with the same
1131 thread ID. In the first case we don't need to do anything; in
1132 the second case we should discard information about the dead
1133 thread and attach to the new one. */
1134 tp = find_thread_ptid (ptid);
1137 /* If tp->private is NULL, then GDB is already attached to this
1138 thread, but we do not know anything about it. We can learn
1139 about it here. This can only happen if we have some other
1140 way besides libthread_db to notice new threads (i.e.
1141 PTRACE_EVENT_CLONE); assume the same mechanism notices thread
1142 exit, so this can not be a stale thread recreated with the
1144 if (tp->private != NULL)
1146 if (!tp->private->dying)
1149 delete_thread (ptid);
1154 if (target_has_execution)
1155 check_thread_signals ();
1157 if (ti_p->ti_state == TD_THR_UNKNOWN || ti_p->ti_state == TD_THR_ZOMBIE)
1158 return 0; /* A zombie thread -- do not attach. */
1160 /* Under GNU/Linux, we have to attach to each and every thread. */
1161 if (target_has_execution
1166 res = lin_lwp_attach_lwp (BUILD_LWP (ti_p->ti_lid, GET_PID (ptid)));
1169 /* Error, stop iterating. */
1174 /* Pretend this thread doesn't exist yet, and keep
1179 /* Otherwise, we sucessfully attached to the thread. */
1182 /* Construct the thread's private data. */
1183 private = xmalloc (sizeof (struct private_thread_info));
1184 memset (private, 0, sizeof (struct private_thread_info));
1186 /* A thread ID of zero may mean the thread library has not initialized
1187 yet. But we shouldn't even get here if that's the case. FIXME:
1188 if we change GDB to always have at least one thread in the thread
1189 list this will have to go somewhere else; maybe private == NULL
1190 until the thread_db target claims it. */
1191 gdb_assert (ti_p->ti_tid != 0);
1192 private->th = *th_p;
1193 private->tid = ti_p->ti_tid;
1195 /* Add the thread to GDB's thread list. */
1197 add_thread_with_info (ptid, private);
1199 tp->private = private;
1201 info = get_thread_db_info (GET_PID (ptid));
1203 /* Enable thread event reporting for this thread, except when
1204 debugging a core file. */
1205 if (target_has_execution)
1207 err = info->td_thr_event_enable_p (th_p, 1);
1209 error (_("Cannot enable thread event reporting for %s: %s"),
1210 target_pid_to_str (ptid), thread_db_err_str (err));
1217 detach_thread (ptid_t ptid)
1219 struct thread_info *thread_info;
1221 /* Don't delete the thread now, because it still reports as active
1222 until it has executed a few instructions after the event
1223 breakpoint - if we deleted it now, "info threads" would cause us
1224 to re-attach to it. Just mark it as having had a TD_DEATH
1225 event. This means that we won't delete it from our thread list
1226 until we notice that it's dead (via prune_threads), or until
1227 something re-uses its thread ID. We'll report the thread exit
1228 when the underlying LWP dies. */
1229 thread_info = find_thread_ptid (ptid);
1230 gdb_assert (thread_info != NULL && thread_info->private != NULL);
1231 thread_info->private->dying = 1;
1235 thread_db_detach (struct target_ops *ops, char *args, int from_tty)
1237 struct target_ops *target_beneath = find_target_beneath (ops);
1238 struct thread_db_info *info;
1240 info = get_thread_db_info (GET_PID (inferior_ptid));
1244 if (target_has_execution)
1246 disable_thread_event_reporting (info);
1248 /* Delete the old thread event breakpoints. Note that
1249 unlike when mourning, we can remove them here because
1250 there's still a live inferior to poke at. In any case,
1251 GDB will not try to insert anything in the inferior when
1252 removing a breakpoint. */
1253 remove_thread_event_breakpoints ();
1256 delete_thread_db_info (GET_PID (inferior_ptid));
1259 target_beneath->to_detach (target_beneath, args, from_tty);
1261 /* NOTE: From this point on, inferior_ptid is null_ptid. */
1263 /* If there are no more processes using libpthread, detach the
1264 thread_db target ops. */
1265 if (!thread_db_list)
1266 unpush_target (&thread_db_ops);
1269 /* Check if PID is currently stopped at the location of a thread event
1270 breakpoint location. If it is, read the event message and act upon
1274 check_event (ptid_t ptid)
1276 struct regcache *regcache = get_thread_regcache (ptid);
1277 struct gdbarch *gdbarch = get_regcache_arch (regcache);
1283 struct thread_db_info *info;
1285 info = get_thread_db_info (GET_PID (ptid));
1287 /* Bail out early if we're not at a thread event breakpoint. */
1288 stop_pc = regcache_read_pc (regcache)
1289 - gdbarch_decr_pc_after_break (gdbarch);
1290 if (stop_pc != info->td_create_bp_addr
1291 && stop_pc != info->td_death_bp_addr)
1294 /* Access an lwp we know is stopped. */
1295 info->proc_handle.ptid = ptid;
1297 /* If we have only looked at the first thread before libpthread was
1298 initialized, we may not know its thread ID yet. Make sure we do
1299 before we add another thread to the list. */
1300 if (!have_threads (ptid))
1301 thread_db_find_new_threads_1 (ptid);
1303 /* If we are at a create breakpoint, we do not know what new lwp
1304 was created and cannot specifically locate the event message for it.
1305 We have to call td_ta_event_getmsg() to get
1306 the latest message. Since we have no way of correlating whether
1307 the event message we get back corresponds to our breakpoint, we must
1308 loop and read all event messages, processing them appropriately.
1309 This guarantees we will process the correct message before continuing
1310 from the breakpoint.
1312 Currently, death events are not enabled. If they are enabled,
1313 the death event can use the td_thr_event_getmsg() interface to
1314 get the message specifically for that lwp and avoid looping
1321 err = info->td_ta_event_getmsg_p (info->thread_agent, &msg);
1324 if (err == TD_NOMSG)
1327 error (_("Cannot get thread event message: %s"),
1328 thread_db_err_str (err));
1331 err = info->td_thr_get_info_p (msg.th_p, &ti);
1333 error (_("Cannot get thread info: %s"), thread_db_err_str (err));
1335 ptid = ptid_build (GET_PID (ptid), ti.ti_lid, 0);
1340 /* Call attach_thread whether or not we already know about a
1341 thread with this thread ID. */
1342 attach_thread (ptid, msg.th_p, &ti);
1348 if (!in_thread_list (ptid))
1349 error (_("Spurious thread death event."));
1351 detach_thread (ptid);
1356 error (_("Spurious thread event."));
1363 thread_db_wait (struct target_ops *ops,
1364 ptid_t ptid, struct target_waitstatus *ourstatus,
1367 struct thread_db_info *info;
1368 struct target_ops *beneath = find_target_beneath (ops);
1370 ptid = beneath->to_wait (beneath, ptid, ourstatus, options);
1372 if (ourstatus->kind == TARGET_WAITKIND_IGNORE)
1375 if (ourstatus->kind == TARGET_WAITKIND_EXITED
1376 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
1379 info = get_thread_db_info (GET_PID (ptid));
1381 /* If this process isn't using thread_db, we're done. */
1385 if (ourstatus->kind == TARGET_WAITKIND_EXECD)
1387 /* New image, it may or may not end up using thread_db. Assume
1388 not unless we find otherwise. */
1389 delete_thread_db_info (GET_PID (ptid));
1390 if (!thread_db_list)
1391 unpush_target (&thread_db_ops);
1393 /* Thread event breakpoints are deleted by
1394 update_breakpoints_after_exec. */
1399 /* If we do not know about the main thread yet, this would be a good time to
1401 if (ourstatus->kind == TARGET_WAITKIND_STOPPED && !have_threads (ptid))
1402 thread_db_find_new_threads_1 (ptid);
1404 if (ourstatus->kind == TARGET_WAITKIND_STOPPED
1405 && ourstatus->value.sig == TARGET_SIGNAL_TRAP)
1406 /* Check for a thread event. */
1409 if (have_threads (ptid))
1411 /* Change ptids back into the higher level PID + TID format. If
1412 the thread is dead and no longer on the thread list, we will
1413 get back a dead ptid. This can occur if the thread death
1414 event gets postponed by other simultaneous events. In such a
1415 case, we want to just ignore the event and continue on. */
1417 ptid = thread_from_lwp (ptid);
1418 if (GET_PID (ptid) == -1)
1419 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
1426 thread_db_mourn_inferior (struct target_ops *ops)
1428 struct target_ops *target_beneath = find_target_beneath (ops);
1430 delete_thread_db_info (GET_PID (inferior_ptid));
1432 target_beneath->to_mourn_inferior (target_beneath);
1434 /* Delete the old thread event breakpoints. Do this after mourning
1435 the inferior, so that we don't try to uninsert them. */
1436 remove_thread_event_breakpoints ();
1438 /* Detach thread_db target ops. */
1439 if (!thread_db_list)
1440 unpush_target (ops);
1443 struct callback_data
1445 struct thread_db_info *info;
1450 find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
1455 struct thread_info *tp;
1456 struct callback_data *cb_data = data;
1457 struct thread_db_info *info = cb_data->info;
1459 err = info->td_thr_get_info_p (th_p, &ti);
1461 error (_("find_new_threads_callback: cannot get thread info: %s"),
1462 thread_db_err_str (err));
1464 if (ti.ti_state == TD_THR_UNKNOWN || ti.ti_state == TD_THR_ZOMBIE)
1465 return 0; /* A zombie -- ignore. */
1469 /* A thread ID of zero means that this is the main thread, but
1470 glibc has not yet initialized thread-local storage and the
1471 pthread library. We do not know what the thread's TID will
1472 be yet. Just enable event reporting and otherwise ignore
1475 /* In that case, we're not stopped in a fork syscall and don't
1476 need this glibc bug workaround. */
1477 info->need_stale_parent_threads_check = 0;
1479 if (target_has_execution)
1481 err = info->td_thr_event_enable_p (th_p, 1);
1483 error (_("Cannot enable thread event reporting for LWP %d: %s"),
1484 (int) ti.ti_lid, thread_db_err_str (err));
1490 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1491 bit expensive, as it needs to open /proc/pid/status, so try to
1492 avoid doing the work if we know we don't have to. */
1493 if (info->need_stale_parent_threads_check)
1495 int tgid = linux_proc_get_tgid (ti.ti_lid);
1497 if (tgid != -1 && tgid != info->pid)
1501 ptid = ptid_build (info->pid, ti.ti_lid, 0);
1502 tp = find_thread_ptid (ptid);
1503 if (tp == NULL || tp->private == NULL)
1505 if (attach_thread (ptid, th_p, &ti))
1506 cb_data->new_threads += 1;
1508 /* Problem attaching this thread; perhaps it exited before we
1510 This could mean that the thread list inside glibc itself is in
1511 inconsistent state, and libthread_db could go on looping forever
1512 (observed with glibc-2.3.6). To prevent that, terminate
1513 iteration: thread_db_find_new_threads_2 will retry. */
1520 /* Helper for thread_db_find_new_threads_2.
1521 Returns number of new threads found. */
1524 find_new_threads_once (struct thread_db_info *info, int iteration,
1527 volatile struct gdb_exception except;
1528 struct callback_data data;
1529 td_err_e err = TD_ERR;
1532 data.new_threads = 0;
1534 TRY_CATCH (except, RETURN_MASK_ERROR)
1536 /* Iterate over all user-space threads to discover new threads. */
1537 err = info->td_ta_thr_iter_p (info->thread_agent,
1538 find_new_threads_callback,
1541 TD_THR_LOWEST_PRIORITY,
1543 TD_THR_ANY_USER_FLAGS);
1546 if (libthread_db_debug)
1548 if (except.reason < 0)
1549 exception_fprintf (gdb_stderr, except,
1550 "Warning: find_new_threads_once: ");
1552 printf_filtered (_("Found %d new threads in iteration %d.\n"),
1553 data.new_threads, iteration);
1559 return data.new_threads;
1562 /* Search for new threads, accessing memory through stopped thread
1563 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1564 searches in a row do not discover any new threads. */
1567 thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new)
1570 struct thread_db_info *info;
1571 int pid = ptid_get_pid (ptid);
1574 info = get_thread_db_info (GET_PID (ptid));
1576 /* Access an lwp we know is stopped. */
1577 info->proc_handle.ptid = ptid;
1581 /* Require 4 successive iterations which do not find any new threads.
1582 The 4 is a heuristic: there is an inherent race here, and I have
1583 seen that 2 iterations in a row are not always sufficient to
1584 "capture" all threads. */
1585 for (i = 0, loop = 0; loop < 4; ++i, ++loop)
1586 if (find_new_threads_once (info, i, NULL) != 0)
1587 /* Found some new threads. Restart the loop from beginning. */
1592 find_new_threads_once (info, 0, &err);
1594 error (_("Cannot find new threads: %s"), thread_db_err_str (err));
1599 thread_db_find_new_threads_1 (ptid_t ptid)
1601 thread_db_find_new_threads_2 (ptid, 0);
1605 update_thread_core (struct lwp_info *info, void *closure)
1607 info->core = linux_common_core_of_thread (info->ptid);
1612 thread_db_find_new_threads (struct target_ops *ops)
1614 struct thread_db_info *info;
1615 struct inferior *inf;
1619 struct thread_info *thread;
1624 info = get_thread_db_info (inf->pid);
1628 thread = any_live_thread_of_process (inf->pid);
1629 if (thread == NULL || thread->executing)
1632 thread_db_find_new_threads_1 (thread->ptid);
1635 if (target_has_execution)
1636 iterate_over_lwps (minus_one_ptid /* iterate over all */,
1637 update_thread_core, NULL);
1641 thread_db_pid_to_str (struct target_ops *ops, ptid_t ptid)
1643 struct thread_info *thread_info = find_thread_ptid (ptid);
1644 struct target_ops *beneath;
1646 if (thread_info != NULL && thread_info->private != NULL)
1648 static char buf[64];
1651 tid = thread_info->private->tid;
1652 snprintf (buf, sizeof (buf), "Thread 0x%lx (LWP %ld)",
1653 tid, GET_LWP (ptid));
1658 beneath = find_target_beneath (ops);
1659 if (beneath->to_pid_to_str (beneath, ptid))
1660 return beneath->to_pid_to_str (beneath, ptid);
1662 return normal_pid_to_str (ptid);
1665 /* Return a string describing the state of the thread specified by
1669 thread_db_extra_thread_info (struct thread_info *info)
1671 if (info->private == NULL)
1674 if (info->private->dying)
1680 /* Get the address of the thread local variable in load module LM which
1681 is stored at OFFSET within the thread local storage for thread PTID. */
1684 thread_db_get_thread_local_address (struct target_ops *ops,
1689 struct thread_info *thread_info;
1690 struct target_ops *beneath;
1692 /* If we have not discovered any threads yet, check now. */
1693 if (!have_threads (ptid))
1694 thread_db_find_new_threads_1 (ptid);
1696 /* Find the matching thread. */
1697 thread_info = find_thread_ptid (ptid);
1699 if (thread_info != NULL && thread_info->private != NULL)
1703 struct thread_db_info *info;
1705 info = get_thread_db_info (GET_PID (ptid));
1707 /* glibc doesn't provide the needed interface. */
1708 if (!info->td_thr_tls_get_addr_p)
1709 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR,
1710 _("No TLS library support"));
1712 /* Caller should have verified that lm != 0. */
1713 gdb_assert (lm != 0);
1715 /* Finally, get the address of the variable. */
1716 /* Note the cast through uintptr_t: this interface only works if
1717 a target address fits in a psaddr_t, which is a host pointer.
1718 So a 32-bit debugger can not access 64-bit TLS through this. */
1719 err = info->td_thr_tls_get_addr_p (&thread_info->private->th,
1720 (psaddr_t)(uintptr_t) lm,
1723 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1724 /* The memory hasn't been allocated, yet. */
1725 if (err == TD_NOTALLOC)
1726 /* Now, if libthread_db provided the initialization image's
1727 address, we *could* try to build a non-lvalue value from
1728 the initialization image. */
1729 throw_error (TLS_NOT_ALLOCATED_YET_ERROR,
1730 _("TLS not allocated yet"));
1733 /* Something else went wrong. */
1735 throw_error (TLS_GENERIC_ERROR,
1736 (("%s")), thread_db_err_str (err));
1738 /* Cast assuming host == target. Joy. */
1739 /* Do proper sign extension for the target. */
1740 gdb_assert (exec_bfd);
1741 return (bfd_get_sign_extend_vma (exec_bfd) > 0
1742 ? (CORE_ADDR) (intptr_t) address
1743 : (CORE_ADDR) (uintptr_t) address);
1746 beneath = find_target_beneath (ops);
1747 if (beneath->to_get_thread_local_address)
1748 return beneath->to_get_thread_local_address (beneath, ptid, lm, offset);
1750 throw_error (TLS_GENERIC_ERROR,
1751 _("TLS not supported on this target"));
1754 /* Callback routine used to find a thread based on the TID part of
1758 thread_db_find_thread_from_tid (struct thread_info *thread, void *data)
1760 long *tid = (long *) data;
1762 if (thread->private->tid == *tid)
1768 /* Implement the to_get_ada_task_ptid target method for this target. */
1771 thread_db_get_ada_task_ptid (long lwp, long thread)
1773 struct thread_info *thread_info;
1775 thread_db_find_new_threads_1 (inferior_ptid);
1776 thread_info = iterate_over_threads (thread_db_find_thread_from_tid, &thread);
1778 gdb_assert (thread_info != NULL);
1780 return (thread_info->ptid);
1784 thread_db_resume (struct target_ops *ops,
1785 ptid_t ptid, int step, enum target_signal signo)
1787 struct target_ops *beneath = find_target_beneath (ops);
1788 struct thread_db_info *info;
1790 if (ptid_equal (ptid, minus_one_ptid))
1791 info = get_thread_db_info (GET_PID (inferior_ptid));
1793 info = get_thread_db_info (GET_PID (ptid));
1795 /* This workaround is only needed for child fork lwps stopped in a
1796 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1797 workaround can be disabled. */
1799 info->need_stale_parent_threads_check = 0;
1801 beneath->to_resume (beneath, ptid, step, signo);
1805 init_thread_db_ops (void)
1807 thread_db_ops.to_shortname = "multi-thread";
1808 thread_db_ops.to_longname = "multi-threaded child process.";
1809 thread_db_ops.to_doc = "Threads and pthreads support.";
1810 thread_db_ops.to_detach = thread_db_detach;
1811 thread_db_ops.to_wait = thread_db_wait;
1812 thread_db_ops.to_resume = thread_db_resume;
1813 thread_db_ops.to_mourn_inferior = thread_db_mourn_inferior;
1814 thread_db_ops.to_find_new_threads = thread_db_find_new_threads;
1815 thread_db_ops.to_pid_to_str = thread_db_pid_to_str;
1816 thread_db_ops.to_stratum = thread_stratum;
1817 thread_db_ops.to_has_thread_control = tc_schedlock;
1818 thread_db_ops.to_get_thread_local_address
1819 = thread_db_get_thread_local_address;
1820 thread_db_ops.to_extra_thread_info = thread_db_extra_thread_info;
1821 thread_db_ops.to_get_ada_task_ptid = thread_db_get_ada_task_ptid;
1822 thread_db_ops.to_magic = OPS_MAGIC;
1825 /* Provide a prototype to silence -Wmissing-prototypes. */
1826 extern initialize_file_ftype _initialize_thread_db;
1829 _initialize_thread_db (void)
1831 init_thread_db_ops ();
1832 add_target (&thread_db_ops);
1834 /* Defer loading of libthread_db.so until inferior is running.
1835 This allows gdb to load correct libthread_db for a given
1836 executable -- there could be mutiple versions of glibc,
1837 compiled with LinuxThreads or NPTL, and until there is
1838 a running inferior, we can't tell which libthread_db is
1839 the correct one to load. */
1841 libthread_db_search_path = xstrdup (LIBTHREAD_DB_SEARCH_PATH);
1843 add_setshow_optional_filename_cmd ("libthread-db-search-path",
1845 &libthread_db_search_path, _("\
1846 Set search path for libthread_db."), _("\
1847 Show the current search path or libthread_db."), _("\
1848 This path is used to search for libthread_db to be loaded into \
1850 Its value is a colon (':') separate list of directories to search.\n\
1851 Setting the search path to an empty list resets it to its default value."),
1852 set_libthread_db_search_path,
1854 &setlist, &showlist);
1856 add_setshow_zinteger_cmd ("libthread-db", class_maintenance,
1857 &libthread_db_debug, _("\
1858 Set libthread-db debugging."), _("\
1859 Show libthread-db debugging."), _("\
1860 When non-zero, libthread-db debugging is enabled."),
1862 show_libthread_db_debug,
1863 &setdebuglist, &showdebuglist);
1865 /* Add ourselves to objfile event chain. */
1866 observer_attach_new_objfile (thread_db_new_objfile);
1868 /* Add ourselves to inferior_created event chain.
1869 This is needed to handle debugging statically linked programs where
1870 the new_objfile observer won't get called for libpthread. */
1871 observer_attach_inferior_created (thread_db_inferior_created);