1 /* libthread_db assisted debugging support, generic parts.
3 Copyright (C) 1999-2015 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_proc_service.h"
23 #include "nat/gdb_thread_db.h"
28 #include "gdbthread.h"
36 #include "solib-svr4.h"
39 #include "linux-nat.h"
40 #include "nat/linux-procfs.h"
41 #include "nat/linux-ptrace.h"
42 #include "nat/linux-osdata.h"
43 #include "auto-load.h"
44 #include "cli/cli-utils.h"
47 #include "nat/linux-namespaces.h"
49 /* GNU/Linux libthread_db support.
51 libthread_db is a library, provided along with libpthread.so, which
52 exposes the internals of the thread library to a debugger. It
53 allows GDB to find existing threads, new threads as they are
54 created, thread IDs (usually, the result of pthread_self), and
55 thread-local variables.
57 The libthread_db interface originates on Solaris, where it is
58 both more powerful and more complicated. This implementation
59 only works for LinuxThreads and NPTL, the two glibc threading
60 libraries. It assumes that each thread is permanently assigned
61 to a single light-weight process (LWP).
63 libthread_db-specific information is stored in the "private" field
64 of struct thread_info. When the field is NULL we do not yet have
65 information about the new thread; this could be temporary (created,
66 but the thread library's data structures do not reflect it yet)
67 or permanent (created using clone instead of pthread_create).
69 Process IDs managed by linux-thread-db.c match those used by
70 linux-nat.c: a common PID for all processes, an LWP ID for each
71 thread, and no TID. We save the TID in private. Keeping it out
72 of the ptid_t prevents thread IDs changing when libpthread is
73 loaded or unloaded. */
75 static char *libthread_db_search_path
;
77 /* Set to non-zero if thread_db auto-loading is enabled
78 by the "set auto-load libthread-db" command. */
79 static int auto_load_thread_db
= 1;
81 /* Returns true if we need to use thread_db thread create/death event
82 breakpoints to learn about threads. */
85 thread_db_use_events (void)
87 /* Not necessary if the kernel supports clone events. */
88 return !linux_supports_traceclone ();
91 /* "show" command for the auto_load_thread_db configuration variable. */
94 show_auto_load_thread_db (struct ui_file
*file
, int from_tty
,
95 struct cmd_list_element
*c
, const char *value
)
97 fprintf_filtered (file
, _("Auto-loading of inferior specific libthread_db "
103 set_libthread_db_search_path (char *ignored
, int from_tty
,
104 struct cmd_list_element
*c
)
106 if (*libthread_db_search_path
== '\0')
108 xfree (libthread_db_search_path
);
109 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
113 /* If non-zero, print details of libthread_db processing. */
115 static unsigned int libthread_db_debug
;
118 show_libthread_db_debug (struct ui_file
*file
, int from_tty
,
119 struct cmd_list_element
*c
, const char *value
)
121 fprintf_filtered (file
, _("libthread-db debugging is %s.\n"), value
);
124 /* If we're running on GNU/Linux, we must explicitly attach to any new
127 /* This module's target vector. */
128 static struct target_ops thread_db_ops
;
130 /* Non-zero if we have determined the signals used by the threads
132 static int thread_signals
;
133 static sigset_t thread_stop_set
;
134 static sigset_t thread_print_set
;
136 struct thread_db_info
138 struct thread_db_info
*next
;
140 /* Process id this object refers to. */
143 /* Handle from dlopen for libthread_db.so. */
146 /* Absolute pathname from gdb_realpath to disk file used for dlopen-ing
147 HANDLE. It may be NULL for system library. */
150 /* Structure that identifies the child process for the
151 <proc_service.h> interface. */
152 struct ps_prochandle proc_handle
;
154 /* Connection to the libthread_db library. */
155 td_thragent_t
*thread_agent
;
157 /* True if we need to apply the workaround for glibc/BZ5983. When
158 we catch a PTRACE_O_TRACEFORK, and go query the child's thread
159 list, nptl_db returns the parent's threads in addition to the new
160 (single) child thread. If this flag is set, we do extra work to
161 be able to ignore such stale entries. */
162 int need_stale_parent_threads_check
;
164 /* Location of the thread creation event breakpoint. The code at
165 this location in the child process will be called by the pthread
166 library whenever a new thread is created. By setting a special
167 breakpoint at this location, GDB can detect when a new thread is
168 created. We obtain this location via the td_ta_event_addr
170 CORE_ADDR td_create_bp_addr
;
172 /* Location of the thread death event breakpoint. */
173 CORE_ADDR td_death_bp_addr
;
175 /* Pointers to the libthread_db functions. */
177 td_init_ftype
*td_init_p
;
178 td_ta_new_ftype
*td_ta_new_p
;
179 td_ta_map_lwp2thr_ftype
*td_ta_map_lwp2thr_p
;
180 td_ta_thr_iter_ftype
*td_ta_thr_iter_p
;
181 td_ta_event_addr_ftype
*td_ta_event_addr_p
;
182 td_ta_set_event_ftype
*td_ta_set_event_p
;
183 td_ta_clear_event_ftype
*td_ta_clear_event_p
;
184 td_ta_event_getmsg_ftype
* td_ta_event_getmsg_p
;
185 td_thr_validate_ftype
*td_thr_validate_p
;
186 td_thr_get_info_ftype
*td_thr_get_info_p
;
187 td_thr_event_enable_ftype
*td_thr_event_enable_p
;
188 td_thr_tls_get_addr_ftype
*td_thr_tls_get_addr_p
;
189 td_thr_tlsbase_ftype
*td_thr_tlsbase_p
;
192 /* List of known processes using thread_db, and the required
194 struct thread_db_info
*thread_db_list
;
196 static void thread_db_find_new_threads_1 (ptid_t ptid
);
197 static void thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
);
199 static void check_thread_signals (void);
201 static void record_thread (struct thread_db_info
*info
,
202 struct thread_info
*tp
,
203 ptid_t ptid
, const td_thrhandle_t
*th_p
,
204 const td_thrinfo_t
*ti_p
);
206 /* Add the current inferior to the list of processes using libpthread.
207 Return a pointer to the newly allocated object that was added to
208 THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
211 static struct thread_db_info
*
212 add_thread_db_info (void *handle
)
214 struct thread_db_info
*info
= XCNEW (struct thread_db_info
);
216 info
->pid
= ptid_get_pid (inferior_ptid
);
217 info
->handle
= handle
;
219 /* The workaround works by reading from /proc/pid/status, so it is
220 disabled for core files. */
221 if (target_has_execution
)
222 info
->need_stale_parent_threads_check
= 1;
224 info
->next
= thread_db_list
;
225 thread_db_list
= info
;
230 /* Return the thread_db_info object representing the bookkeeping
231 related to process PID, if any; NULL otherwise. */
233 static struct thread_db_info
*
234 get_thread_db_info (int pid
)
236 struct thread_db_info
*info
;
238 for (info
= thread_db_list
; info
; info
= info
->next
)
239 if (pid
== info
->pid
)
245 /* When PID has exited or has been detached, we no longer want to keep
246 track of it as using libpthread. Call this function to discard
247 thread_db related info related to PID. Note that this closes
248 LIBTHREAD_DB_SO's dlopen'ed handle. */
251 delete_thread_db_info (int pid
)
253 struct thread_db_info
*info
, *info_prev
;
257 for (info
= thread_db_list
; info
; info_prev
= info
, info
= info
->next
)
258 if (pid
== info
->pid
)
264 if (info
->handle
!= NULL
)
265 dlclose (info
->handle
);
267 xfree (info
->filename
);
270 info_prev
->next
= info
->next
;
272 thread_db_list
= info
->next
;
277 /* Prototypes for local functions. */
278 static int attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
279 const td_thrinfo_t
*ti_p
);
280 static void detach_thread (ptid_t ptid
);
283 /* Use "struct private_thread_info" to cache thread state. This is
284 a substantial optimization. */
286 struct private_thread_info
288 /* Flag set when we see a TD_DEATH event for this thread. */
289 unsigned int dying
:1;
291 /* Cached thread state. */
298 thread_db_err_str (td_err_e err
)
305 return "generic 'call succeeded'";
307 return "generic error";
309 return "no thread to satisfy query";
311 return "no sync handle to satisfy query";
313 return "no LWP to satisfy query";
315 return "invalid process handle";
317 return "invalid thread handle";
319 return "invalid synchronization handle";
321 return "invalid thread agent";
323 return "invalid key";
325 return "no event message for getmsg";
327 return "FPU register set not available";
329 return "application not linked with libthread";
331 return "requested event is not supported";
333 return "capability not available";
335 return "debugger service failed";
337 return "operation not applicable to";
339 return "no thread-specific data for this thread";
341 return "malloc failed";
343 return "only part of register set was written/read";
345 return "X register set not available for this thread";
346 #ifdef THREAD_DB_HAS_TD_NOTALLOC
348 return "thread has not yet allocated TLS for given module";
350 #ifdef THREAD_DB_HAS_TD_VERSION
352 return "versions of libpthread and libthread_db do not match";
354 #ifdef THREAD_DB_HAS_TD_NOTLS
356 return "there is no TLS segment in the given module";
359 snprintf (buf
, sizeof (buf
), "unknown thread_db error '%d'", err
);
364 /* Return 1 if any threads have been registered. There may be none if
365 the threading library is not fully initialized yet. */
368 have_threads_callback (struct thread_info
*thread
, void *args
)
370 int pid
= * (int *) args
;
372 if (ptid_get_pid (thread
->ptid
) != pid
)
375 return thread
->priv
!= NULL
;
379 have_threads (ptid_t ptid
)
381 int pid
= ptid_get_pid (ptid
);
383 return iterate_over_threads (have_threads_callback
, &pid
) != NULL
;
387 /* Fetch the user-level thread id of PTID. */
390 thread_from_lwp (ptid_t ptid
)
395 struct thread_db_info
*info
;
396 struct thread_info
*tp
;
398 /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
401 /* This ptid comes from linux-nat.c, which should always fill in the
403 gdb_assert (ptid_get_lwp (ptid
) != 0);
405 info
= get_thread_db_info (ptid_get_pid (ptid
));
407 /* Access an lwp we know is stopped. */
408 info
->proc_handle
.ptid
= ptid
;
409 err
= info
->td_ta_map_lwp2thr_p (info
->thread_agent
, ptid_get_lwp (ptid
),
412 error (_("Cannot find user-level thread for LWP %ld: %s"),
413 ptid_get_lwp (ptid
), thread_db_err_str (err
));
415 err
= info
->td_thr_get_info_p (&th
, &ti
);
417 error (_("thread_get_info_callback: cannot get thread info: %s"),
418 thread_db_err_str (err
));
420 /* Fill the cache. */
421 tp
= find_thread_ptid (ptid
);
422 record_thread (info
, tp
, ptid
, &th
, &ti
);
426 /* See linux-nat.h. */
429 thread_db_notice_clone (ptid_t parent
, ptid_t child
)
434 struct thread_db_info
*info
;
436 info
= get_thread_db_info (ptid_get_pid (child
));
441 thread_from_lwp (child
);
443 /* If we do not know about the main thread yet, this would be a good
445 thread_from_lwp (parent
);
450 verbose_dlsym (void *handle
, const char *name
)
452 void *sym
= dlsym (handle
, name
);
454 warning (_("Symbol \"%s\" not found in libthread_db: %s"),
460 enable_thread_event (td_event_e event
, CORE_ADDR
*bp
)
464 struct thread_db_info
*info
;
466 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
468 /* Access an lwp we know is stopped. */
469 info
->proc_handle
.ptid
= inferior_ptid
;
471 /* Get the breakpoint address for thread EVENT. */
472 err
= info
->td_ta_event_addr_p (info
->thread_agent
, event
, ¬ify
);
476 /* Set up the breakpoint. */
477 gdb_assert (exec_bfd
);
478 (*bp
) = (gdbarch_convert_from_func_ptr_addr
480 /* Do proper sign extension for the target. */
481 (bfd_get_sign_extend_vma (exec_bfd
) > 0
482 ? (CORE_ADDR
) (intptr_t) notify
.u
.bptaddr
483 : (CORE_ADDR
) (uintptr_t) notify
.u
.bptaddr
),
485 create_thread_event_breakpoint (target_gdbarch (), *bp
);
490 /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
491 return 1 if this version is lower (and not equal) to
492 VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
495 inferior_has_bug (const char *ver_symbol
, int ver_major_min
, int ver_minor_min
)
497 struct bound_minimal_symbol version_msym
;
498 CORE_ADDR version_addr
;
500 int err
, got
, retval
= 0;
502 version_msym
= lookup_minimal_symbol (ver_symbol
, NULL
, NULL
);
503 if (version_msym
.minsym
== NULL
)
506 version_addr
= BMSYMBOL_VALUE_ADDRESS (version_msym
);
507 got
= target_read_string (version_addr
, &version
, 32, &err
);
508 if (err
== 0 && memchr (version
, 0, got
) == &version
[got
-1])
512 retval
= (sscanf (version
, "%d.%d", &major
, &minor
) == 2
513 && (major
< ver_major_min
514 || (major
== ver_major_min
&& minor
< ver_minor_min
)));
522 enable_thread_event_reporting (void)
524 td_thr_events_t events
;
526 struct thread_db_info
*info
;
528 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
530 /* We cannot use the thread event reporting facility if these
531 functions aren't available. */
532 if (info
->td_ta_event_addr_p
== NULL
533 || info
->td_ta_set_event_p
== NULL
534 || info
->td_ta_event_getmsg_p
== NULL
535 || info
->td_thr_event_enable_p
== NULL
)
538 /* Set the process wide mask saying which events we're interested in. */
539 td_event_emptyset (&events
);
540 td_event_addset (&events
, TD_CREATE
);
542 /* There is a bug fixed between linuxthreads 2.1.3 and 2.2 by
543 commit 2e4581e4fba917f1779cd0a010a45698586c190a
544 * manager.c (pthread_exited): Correctly report event as TD_REAP
545 instead of TD_DEATH. Fix comments.
546 where event reporting facility is broken for TD_DEATH events,
547 so don't enable it if we have glibc but a lower version. */
548 if (!inferior_has_bug ("__linuxthreads_version", 2, 2))
549 td_event_addset (&events
, TD_DEATH
);
551 err
= info
->td_ta_set_event_p (info
->thread_agent
, &events
);
554 warning (_("Unable to set global thread event mask: %s"),
555 thread_db_err_str (err
));
559 /* Delete previous thread event breakpoints, if any. */
560 remove_thread_event_breakpoints ();
561 info
->td_create_bp_addr
= 0;
562 info
->td_death_bp_addr
= 0;
564 /* Set up the thread creation event. */
565 err
= enable_thread_event (TD_CREATE
, &info
->td_create_bp_addr
);
568 warning (_("Unable to get location for thread creation breakpoint: %s"),
569 thread_db_err_str (err
));
573 /* Set up the thread death event. */
574 err
= enable_thread_event (TD_DEATH
, &info
->td_death_bp_addr
);
577 warning (_("Unable to get location for thread death breakpoint: %s"),
578 thread_db_err_str (err
));
583 /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
586 Return 1 if the caller should abort libthread_db initialization. Return 0
590 thread_db_find_new_threads_silently (ptid_t ptid
)
595 thread_db_find_new_threads_2 (ptid
, 1);
598 CATCH (except
, RETURN_MASK_ERROR
)
600 if (libthread_db_debug
)
601 exception_fprintf (gdb_stdlog
, except
,
602 "Warning: thread_db_find_new_threads_silently: ");
604 /* There is a bug fixed between nptl 2.6.1 and 2.7 by
605 commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
606 where calls to td_thr_get_info fail with TD_ERR for statically linked
607 executables if td_thr_get_info is called before glibc has initialized
610 If the nptl bug is NOT present in the inferior and still thread_db
611 reports an error return 1. It means the inferior has corrupted thread
612 list and GDB should fall back only to LWPs.
614 If the nptl bug is present in the inferior return 0 to silently ignore
615 such errors, and let gdb enumerate threads again later. In such case
616 GDB cannot properly display LWPs if the inferior thread list is
617 corrupted. For core files it does not apply, no 'later enumeration'
620 if (!target_has_execution
|| !inferior_has_bug ("nptl_version", 2, 7))
622 exception_fprintf (gdb_stderr
, except
,
623 _("Warning: couldn't activate thread debugging "
624 "using libthread_db: "));
633 /* Lookup a library in which given symbol resides.
634 Note: this is looking in GDB process, not in the inferior.
635 Returns library name, or NULL. */
638 dladdr_to_soname (const void *addr
)
642 if (dladdr (addr
, &info
) != 0)
643 return info
.dli_fname
;
647 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
649 Failure could happen if libthread_db does not have symbols we expect,
650 or when it refuses to work with the current inferior (e.g. due to
651 version mismatch between libthread_db and libpthread). */
654 try_thread_db_load_1 (struct thread_db_info
*info
)
658 /* Initialize pointers to the dynamic library functions we will use.
659 Essential functions first. */
661 #define TDB_VERBOSE_DLSYM(info, func) \
662 info->func ## _p = (func ## _ftype *) verbose_dlsym (info->handle, #func)
664 #define TDB_DLSYM(info, func) \
665 info->func ## _p = (func ## _ftype *) dlsym (info->handle, #func)
674 CHK (TDB_VERBOSE_DLSYM (info
, td_init
));
676 err
= info
->td_init_p ();
679 warning (_("Cannot initialize libthread_db: %s"),
680 thread_db_err_str (err
));
684 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_new
));
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 fprintf_unfiltered (gdb_stdlog
, _("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 /* These are essential. */
714 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_map_lwp2thr
));
715 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_thr_iter
));
716 CHK (TDB_VERBOSE_DLSYM (info
, td_thr_validate
));
717 CHK (TDB_VERBOSE_DLSYM (info
, td_thr_get_info
));
719 /* These are not essential. */
720 TDB_DLSYM (info
, td_ta_event_addr
);
721 TDB_DLSYM (info
, td_ta_set_event
);
722 TDB_DLSYM (info
, td_ta_clear_event
);
723 TDB_DLSYM (info
, td_ta_event_getmsg
);
724 TDB_DLSYM (info
, td_thr_event_enable
);
725 TDB_DLSYM (info
, td_thr_tls_get_addr
);
726 TDB_DLSYM (info
, td_thr_tlsbase
);
728 #undef TDB_VERBOSE_DLSYM
732 /* It's best to avoid td_ta_thr_iter if possible. That walks data
733 structures in the inferior's address space that may be corrupted,
734 or, if the target is running, may change while we walk them. If
735 there's execution (and /proc is mounted), then we're already
736 attached to all LWPs. Use thread_from_lwp, which uses
737 td_ta_map_lwp2thr instead, which does not walk the thread list.
739 td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that
740 currently on core targets, as it uses ptrace directly. */
741 if (target_has_execution
742 && linux_proc_task_list_dir_exists (ptid_get_pid (inferior_ptid
)))
745 int pid
= ptid_get_pid (inferior_ptid
);
747 linux_stop_and_wait_all_lwps ();
750 if (ptid_get_pid (lp
->ptid
) == pid
)
751 thread_from_lwp (lp
->ptid
);
753 linux_unstop_all_lwps ();
755 else if (thread_db_find_new_threads_silently (inferior_ptid
) != 0)
757 /* Even if libthread_db initializes, if the thread list is
758 corrupted, we'd not manage to list any threads. Better reject this
759 thread_db, and fall back to at least listing LWPs. */
763 printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
765 if (*libthread_db_search_path
|| libthread_db_debug
)
767 struct ui_file
*file
;
770 library
= dladdr_to_soname (*info
->td_ta_new_p
);
772 library
= LIBTHREAD_DB_SO
;
774 /* If we'd print this to gdb_stdout when debug output is
775 disabled, still print it to gdb_stdout if debug output is
776 enabled. User visible output should not depend on debug
778 file
= *libthread_db_search_path
!= '\0' ? gdb_stdout
: gdb_stdlog
;
779 fprintf_unfiltered (file
, _("Using host libthread_db library \"%s\".\n"),
783 /* The thread library was detected. Activate the thread_db target
784 if this is the first process using it. */
785 if (thread_db_list
->next
== NULL
)
786 push_target (&thread_db_ops
);
788 /* Enable event reporting, but not when debugging a core file. */
789 if (target_has_execution
&& thread_db_use_events ())
790 enable_thread_event_reporting ();
795 /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
796 relative, or just LIBTHREAD_DB. */
799 try_thread_db_load (const char *library
, int check_auto_load_safe
)
802 struct thread_db_info
*info
;
804 if (libthread_db_debug
)
805 fprintf_unfiltered (gdb_stdlog
,
806 _("Trying host libthread_db library: %s.\n"),
809 if (check_auto_load_safe
)
811 if (access (library
, R_OK
) != 0)
813 /* Do not print warnings by file_is_auto_load_safe if the library does
814 not exist at this place. */
815 if (libthread_db_debug
)
816 fprintf_unfiltered (gdb_stdlog
, _("open failed: %s.\n"),
817 safe_strerror (errno
));
821 if (!file_is_auto_load_safe (library
, _("auto-load: Loading libthread-db "
822 "library \"%s\" from explicit "
828 handle
= dlopen (library
, RTLD_NOW
);
831 if (libthread_db_debug
)
832 fprintf_unfiltered (gdb_stdlog
, _("dlopen failed: %s.\n"), dlerror ());
836 if (libthread_db_debug
&& strchr (library
, '/') == NULL
)
840 td_init
= dlsym (handle
, "td_init");
843 const char *const libpath
= dladdr_to_soname (td_init
);
846 fprintf_unfiltered (gdb_stdlog
, _("Host %s resolved to: %s.\n"),
851 info
= add_thread_db_info (handle
);
853 /* Do not save system library name, that one is always trusted. */
854 if (strchr (library
, '/') != NULL
)
855 info
->filename
= gdb_realpath (library
);
857 if (try_thread_db_load_1 (info
))
860 /* This library "refused" to work on current inferior. */
861 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
865 /* Subroutine of try_thread_db_load_from_pdir to simplify it.
866 Try loading libthread_db in directory(OBJ)/SUBDIR.
867 SUBDIR may be NULL. It may also be something like "../lib64".
868 The result is true for success. */
871 try_thread_db_load_from_pdir_1 (struct objfile
*obj
, const char *subdir
)
873 struct cleanup
*cleanup
;
876 const char *obj_name
= objfile_name (obj
);
878 if (obj_name
[0] != '/')
880 warning (_("Expected absolute pathname for libpthread in the"
881 " inferior, but got %s."), obj_name
);
885 path
= xmalloc (strlen (obj_name
) + (subdir
? strlen (subdir
) + 1 : 0)
886 + 1 + strlen (LIBTHREAD_DB_SO
) + 1);
887 cleanup
= make_cleanup (xfree
, path
);
889 strcpy (path
, obj_name
);
890 cp
= strrchr (path
, '/');
891 /* This should at minimum hit the first character. */
892 gdb_assert (cp
!= NULL
);
899 strcat (cp
, LIBTHREAD_DB_SO
);
901 result
= try_thread_db_load (path
, 1);
903 do_cleanups (cleanup
);
907 /* Handle $pdir in libthread-db-search-path.
908 Look for libthread_db in directory(libpthread)/SUBDIR.
909 SUBDIR may be NULL. It may also be something like "../lib64".
910 The result is true for success. */
913 try_thread_db_load_from_pdir (const char *subdir
)
917 if (!auto_load_thread_db
)
921 if (libpthread_name_p (objfile_name (obj
)))
923 if (try_thread_db_load_from_pdir_1 (obj
, subdir
))
926 /* We may have found the separate-debug-info version of
927 libpthread, and it may live in a directory without a matching
929 if (obj
->separate_debug_objfile_backlink
!= NULL
)
930 return try_thread_db_load_from_pdir_1 (obj
->separate_debug_objfile_backlink
,
939 /* Handle $sdir in libthread-db-search-path.
940 Look for libthread_db in the system dirs, or wherever a plain
941 dlopen(file_without_path) will look.
942 The result is true for success. */
945 try_thread_db_load_from_sdir (void)
947 return try_thread_db_load (LIBTHREAD_DB_SO
, 0);
950 /* Try to load libthread_db from directory DIR of length DIR_LEN.
951 The result is true for success. */
954 try_thread_db_load_from_dir (const char *dir
, size_t dir_len
)
956 struct cleanup
*cleanup
;
960 if (!auto_load_thread_db
)
963 path
= xmalloc (dir_len
+ 1 + strlen (LIBTHREAD_DB_SO
) + 1);
964 cleanup
= make_cleanup (xfree
, path
);
966 memcpy (path
, dir
, dir_len
);
968 strcpy (path
+ dir_len
+ 1, LIBTHREAD_DB_SO
);
970 result
= try_thread_db_load (path
, 1);
972 do_cleanups (cleanup
);
976 /* Search libthread_db_search_path for libthread_db which "agrees"
977 to work on current inferior.
978 The result is true for success. */
981 thread_db_load_search (void)
983 VEC (char_ptr
) *dir_vec
;
984 struct cleanup
*cleanups
;
988 dir_vec
= dirnames_to_char_ptr_vec (libthread_db_search_path
);
989 cleanups
= make_cleanup_free_char_ptr_vec (dir_vec
);
991 for (i
= 0; VEC_iterate (char_ptr
, dir_vec
, i
, this_dir
); ++i
)
993 const int pdir_len
= sizeof ("$pdir") - 1;
996 this_dir_len
= strlen (this_dir
);
998 if (strncmp (this_dir
, "$pdir", pdir_len
) == 0
999 && (this_dir
[pdir_len
] == '\0'
1000 || this_dir
[pdir_len
] == '/'))
1002 char *subdir
= NULL
;
1003 struct cleanup
*free_subdir_cleanup
1004 = make_cleanup (null_cleanup
, NULL
);
1006 if (this_dir
[pdir_len
] == '/')
1008 subdir
= xmalloc (strlen (this_dir
));
1009 make_cleanup (xfree
, subdir
);
1010 strcpy (subdir
, this_dir
+ pdir_len
+ 1);
1012 rc
= try_thread_db_load_from_pdir (subdir
);
1013 do_cleanups (free_subdir_cleanup
);
1017 else if (strcmp (this_dir
, "$sdir") == 0)
1019 if (try_thread_db_load_from_sdir ())
1027 if (try_thread_db_load_from_dir (this_dir
, this_dir_len
))
1035 do_cleanups (cleanups
);
1036 if (libthread_db_debug
)
1037 fprintf_unfiltered (gdb_stdlog
,
1038 _("thread_db_load_search returning %d\n"), rc
);
1042 /* Return non-zero if the inferior has a libpthread. */
1045 has_libpthread (void)
1047 struct objfile
*obj
;
1050 if (libpthread_name_p (objfile_name (obj
)))
1056 /* Attempt to load and initialize libthread_db.
1057 Return 1 on success. */
1060 thread_db_load (void)
1062 struct thread_db_info
*info
;
1064 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1069 /* Don't attempt to use thread_db on executables not running
1071 if (!target_has_registers
)
1074 /* Don't attempt to use thread_db for remote targets. */
1075 if (!(target_can_run (¤t_target
) || core_bfd
))
1078 if (thread_db_load_search ())
1081 /* We couldn't find a libthread_db.
1082 If the inferior has a libpthread warn the user. */
1083 if (has_libpthread ())
1085 warning (_("Unable to find libthread_db matching inferior's thread"
1086 " library, thread debugging will not be available."));
1090 /* Either this executable isn't using libpthread at all, or it is
1091 statically linked. Since we can't easily distinguish these two cases,
1092 no warning is issued. */
1097 disable_thread_event_reporting (struct thread_db_info
*info
)
1099 if (info
->td_ta_clear_event_p
!= NULL
)
1101 td_thr_events_t events
;
1103 /* Set the process wide mask saying we aren't interested in any
1105 td_event_fillset (&events
);
1106 info
->td_ta_clear_event_p (info
->thread_agent
, &events
);
1109 info
->td_create_bp_addr
= 0;
1110 info
->td_death_bp_addr
= 0;
1114 check_thread_signals (void)
1116 if (!thread_signals
)
1121 lin_thread_get_thread_signals (&mask
);
1122 sigemptyset (&thread_stop_set
);
1123 sigemptyset (&thread_print_set
);
1125 for (i
= 1; i
< NSIG
; i
++)
1127 if (sigismember (&mask
, i
))
1129 if (signal_stop_update (gdb_signal_from_host (i
), 0))
1130 sigaddset (&thread_stop_set
, i
);
1131 if (signal_print_update (gdb_signal_from_host (i
), 0))
1132 sigaddset (&thread_print_set
, i
);
1139 /* Check whether thread_db is usable. This function is called when
1140 an inferior is created (or otherwise acquired, e.g. attached to)
1141 and when new shared libraries are loaded into a running process. */
1144 check_for_thread_db (void)
1146 /* Do nothing if we couldn't load libthread_db.so.1. */
1147 if (!thread_db_load ())
1151 /* This function is called via the new_objfile observer. */
1154 thread_db_new_objfile (struct objfile
*objfile
)
1156 /* This observer must always be called with inferior_ptid set
1160 /* libpthread with separate debug info has its debug info file already
1161 loaded (and notified without successful thread_db initialization)
1162 the time observer_notify_new_objfile is called for the library itself.
1163 Static executables have their separate debug info loaded already
1164 before the inferior has started. */
1165 && objfile
->separate_debug_objfile_backlink
== NULL
1166 /* Only check for thread_db if we loaded libpthread,
1167 or if this is the main symbol file.
1168 We need to check OBJF_MAINLINE to handle the case of debugging
1169 a statically linked executable AND the symbol file is specified AFTER
1170 the exec file is loaded (e.g., gdb -c core ; file foo).
1171 For dynamically linked executables, libpthread can be near the end
1172 of the list of shared libraries to load, and in an app of several
1173 thousand shared libraries, this can otherwise be painful. */
1174 && ((objfile
->flags
& OBJF_MAINLINE
) != 0
1175 || libpthread_name_p (objfile_name (objfile
))))
1176 check_for_thread_db ();
1180 check_pid_namespace_match (void)
1182 /* Check is only relevant for local targets targets. */
1183 if (target_can_run (¤t_target
))
1185 /* If the child is in a different PID namespace, its idea of its
1186 PID will differ from our idea of its PID. When we scan the
1187 child's thread list, we'll mistakenly think it has no threads
1188 since the thread PID fields won't match the PID we give to
1190 if (!linux_ns_same (ptid_get_pid (inferior_ptid
), LINUX_NS_PID
))
1192 warning (_ ("Target and debugger are in different PID "
1193 "namespaces; thread lists and other data are "
1194 "likely unreliable"));
1199 /* This function is called via the inferior_created observer.
1200 This handles the case of debugging statically linked executables. */
1203 thread_db_inferior_created (struct target_ops
*target
, int from_tty
)
1205 check_pid_namespace_match ();
1206 check_for_thread_db ();
1209 /* Update the thread's state (what's displayed in "info threads"),
1210 from libthread_db thread state information. */
1213 update_thread_state (struct private_thread_info
*priv
,
1214 const td_thrinfo_t
*ti_p
)
1216 priv
->dying
= (ti_p
->ti_state
== TD_THR_UNKNOWN
1217 || ti_p
->ti_state
== TD_THR_ZOMBIE
);
1220 /* Attach to a new thread. This function is called when we receive a
1221 TD_CREATE event or when we iterate over all threads and find one
1222 that wasn't already in our list. Returns true on success. */
1225 attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
1226 const td_thrinfo_t
*ti_p
)
1228 struct thread_info
*tp
;
1229 struct thread_db_info
*info
;
1231 /* If we're being called after a TD_CREATE event, we may already
1232 know about this thread. There are two ways this can happen. We
1233 may have iterated over all threads between the thread creation
1234 and the TD_CREATE event, for instance when the user has issued
1235 the `info threads' command before the SIGTRAP for hitting the
1236 thread creation breakpoint was reported. Alternatively, the
1237 thread may have exited and a new one been created with the same
1238 thread ID. In the first case we don't need to do anything; in
1239 the second case we should discard information about the dead
1240 thread and attach to the new one. */
1241 tp
= find_thread_ptid (ptid
);
1244 /* If tp->priv is NULL, then GDB is already attached to this
1245 thread, but we do not know anything about it. We can learn
1246 about it here. This can only happen if we have some other
1247 way besides libthread_db to notice new threads (i.e.
1248 PTRACE_EVENT_CLONE); assume the same mechanism notices thread
1249 exit, so this can not be a stale thread recreated with the
1251 if (tp
->priv
!= NULL
)
1253 if (!tp
->priv
->dying
)
1256 delete_thread (ptid
);
1261 /* Under GNU/Linux, we have to attach to each and every thread. */
1262 if (target_has_execution
1267 res
= lin_lwp_attach_lwp (ptid_build (ptid_get_pid (ptid
),
1271 /* Error, stop iterating. */
1276 /* Pretend this thread doesn't exist yet, and keep
1281 /* Otherwise, we sucessfully attached to the thread. */
1284 info
= get_thread_db_info (ptid_get_pid (ptid
));
1285 record_thread (info
, tp
, ptid
, th_p
, ti_p
);
1289 /* Record a new thread in GDB's thread list. Creates the thread's
1290 private info. If TP is NULL, creates a new thread. Otherwise,
1294 record_thread (struct thread_db_info
*info
,
1295 struct thread_info
*tp
,
1296 ptid_t ptid
, const td_thrhandle_t
*th_p
,
1297 const td_thrinfo_t
*ti_p
)
1300 struct private_thread_info
*priv
;
1301 int new_thread
= (tp
== NULL
);
1303 /* A thread ID of zero may mean the thread library has not
1304 initialized yet. Leave private == NULL until the thread library
1306 if (ti_p
->ti_tid
== 0)
1309 /* Construct the thread's private data. */
1310 priv
= XCNEW (struct private_thread_info
);
1313 priv
->tid
= ti_p
->ti_tid
;
1314 update_thread_state (priv
, ti_p
);
1316 /* Add the thread to GDB's thread list. If we already know about a
1317 thread with this PTID, but it's marked exited, then the kernel
1318 reused the tid of an old thread. */
1319 if (tp
== NULL
|| tp
->state
== THREAD_EXITED
)
1320 tp
= add_thread_with_info (ptid
, priv
);
1324 /* Enable thread event reporting for this thread, except when
1325 debugging a core file. */
1326 if (target_has_execution
&& thread_db_use_events () && new_thread
)
1328 err
= info
->td_thr_event_enable_p (th_p
, 1);
1330 error (_("Cannot enable thread event reporting for %s: %s"),
1331 target_pid_to_str (ptid
), thread_db_err_str (err
));
1334 if (target_has_execution
)
1335 check_thread_signals ();
1339 detach_thread (ptid_t ptid
)
1341 struct thread_info
*thread_info
;
1343 /* Don't delete the thread now, because it still reports as active
1344 until it has executed a few instructions after the event
1345 breakpoint - if we deleted it now, "info threads" would cause us
1346 to re-attach to it. Just mark it as having had a TD_DEATH
1347 event. This means that we won't delete it from our thread list
1348 until we notice that it's dead (via prune_threads), or until
1349 something re-uses its thread ID. We'll report the thread exit
1350 when the underlying LWP dies. */
1351 thread_info
= find_thread_ptid (ptid
);
1352 gdb_assert (thread_info
!= NULL
&& thread_info
->priv
!= NULL
);
1353 thread_info
->priv
->dying
= 1;
1357 thread_db_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1359 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1360 struct thread_db_info
*info
;
1362 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1366 if (target_has_execution
&& thread_db_use_events ())
1368 disable_thread_event_reporting (info
);
1370 /* Delete the old thread event breakpoints. Note that
1371 unlike when mourning, we can remove them here because
1372 there's still a live inferior to poke at. In any case,
1373 GDB will not try to insert anything in the inferior when
1374 removing a breakpoint. */
1375 remove_thread_event_breakpoints ();
1378 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1381 target_beneath
->to_detach (target_beneath
, args
, from_tty
);
1383 /* NOTE: From this point on, inferior_ptid is null_ptid. */
1385 /* If there are no more processes using libpthread, detach the
1386 thread_db target ops. */
1387 if (!thread_db_list
)
1388 unpush_target (&thread_db_ops
);
1391 /* Check if PID is currently stopped at the location of a thread event
1392 breakpoint location. If it is, read the event message and act upon
1396 check_event (ptid_t ptid
)
1398 struct regcache
*regcache
= get_thread_regcache (ptid
);
1399 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
1405 struct thread_db_info
*info
;
1407 info
= get_thread_db_info (ptid_get_pid (ptid
));
1409 /* Bail out early if we're not at a thread event breakpoint. */
1410 stop_pc
= regcache_read_pc (regcache
);
1411 if (!target_supports_stopped_by_sw_breakpoint ())
1412 stop_pc
-= gdbarch_decr_pc_after_break (gdbarch
);
1414 if (stop_pc
!= info
->td_create_bp_addr
1415 && stop_pc
!= info
->td_death_bp_addr
)
1418 /* Access an lwp we know is stopped. */
1419 info
->proc_handle
.ptid
= ptid
;
1421 /* If we have only looked at the first thread before libpthread was
1422 initialized, we may not know its thread ID yet. Make sure we do
1423 before we add another thread to the list. */
1424 if (!have_threads (ptid
))
1425 thread_db_find_new_threads_1 (ptid
);
1427 /* If we are at a create breakpoint, we do not know what new lwp
1428 was created and cannot specifically locate the event message for it.
1429 We have to call td_ta_event_getmsg() to get
1430 the latest message. Since we have no way of correlating whether
1431 the event message we get back corresponds to our breakpoint, we must
1432 loop and read all event messages, processing them appropriately.
1433 This guarantees we will process the correct message before continuing
1434 from the breakpoint.
1436 Currently, death events are not enabled. If they are enabled,
1437 the death event can use the td_thr_event_getmsg() interface to
1438 get the message specifically for that lwp and avoid looping
1445 err
= info
->td_ta_event_getmsg_p (info
->thread_agent
, &msg
);
1448 if (err
== TD_NOMSG
)
1451 error (_("Cannot get thread event message: %s"),
1452 thread_db_err_str (err
));
1455 err
= info
->td_thr_get_info_p (msg
.th_p
, &ti
);
1457 error (_("Cannot get thread info: %s"), thread_db_err_str (err
));
1459 ptid
= ptid_build (ptid_get_pid (ptid
), ti
.ti_lid
, 0);
1464 /* Call attach_thread whether or not we already know about a
1465 thread with this thread ID. */
1466 attach_thread (ptid
, msg
.th_p
, &ti
);
1472 if (!in_thread_list (ptid
))
1473 error (_("Spurious thread death event."));
1475 detach_thread (ptid
);
1480 error (_("Spurious thread event."));
1487 thread_db_wait (struct target_ops
*ops
,
1488 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
1491 struct thread_db_info
*info
;
1492 struct target_ops
*beneath
= find_target_beneath (ops
);
1494 ptid
= beneath
->to_wait (beneath
, ptid
, ourstatus
, options
);
1496 if (ourstatus
->kind
== TARGET_WAITKIND_IGNORE
)
1499 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
1500 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
1503 info
= get_thread_db_info (ptid_get_pid (ptid
));
1505 /* If this process isn't using thread_db, we're done. */
1509 if (ourstatus
->kind
== TARGET_WAITKIND_EXECD
)
1511 /* New image, it may or may not end up using thread_db. Assume
1512 not unless we find otherwise. */
1513 delete_thread_db_info (ptid_get_pid (ptid
));
1514 if (!thread_db_list
)
1515 unpush_target (&thread_db_ops
);
1517 /* Thread event breakpoints are deleted by
1518 update_breakpoints_after_exec. */
1523 if (ourstatus
->kind
== TARGET_WAITKIND_STOPPED
1524 && ourstatus
->value
.sig
== GDB_SIGNAL_TRAP
)
1525 /* Check for a thread event. */
1528 /* Fill in the thread's user-level thread id and status. */
1529 thread_from_lwp (ptid
);
1535 thread_db_mourn_inferior (struct target_ops
*ops
)
1537 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1539 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1541 target_beneath
->to_mourn_inferior (target_beneath
);
1543 /* Delete the old thread event breakpoints. Do this after mourning
1544 the inferior, so that we don't try to uninsert them. */
1545 remove_thread_event_breakpoints ();
1547 /* Detach thread_db target ops. */
1548 if (!thread_db_list
)
1549 unpush_target (ops
);
1552 struct callback_data
1554 struct thread_db_info
*info
;
1559 find_new_threads_callback (const td_thrhandle_t
*th_p
, void *data
)
1564 struct thread_info
*tp
;
1565 struct callback_data
*cb_data
= data
;
1566 struct thread_db_info
*info
= cb_data
->info
;
1568 err
= info
->td_thr_get_info_p (th_p
, &ti
);
1570 error (_("find_new_threads_callback: cannot get thread info: %s"),
1571 thread_db_err_str (err
));
1573 if (ti
.ti_lid
== -1)
1575 /* A thread with kernel thread ID -1 is either a thread that
1576 exited and was joined, or a thread that is being created but
1577 hasn't started yet, and that is reusing the tcb/stack of a
1578 thread that previously exited and was joined. (glibc marks
1579 terminated and joined threads with kernel thread ID -1. See
1581 if (libthread_db_debug
)
1582 fprintf_unfiltered (gdb_stdlog
,
1583 "thread_db: skipping exited and "
1584 "joined thread (0x%lx)\n", ti
.ti_tid
);
1590 /* A thread ID of zero means that this is the main thread, but
1591 glibc has not yet initialized thread-local storage and the
1592 pthread library. We do not know what the thread's TID will
1593 be yet. Just enable event reporting and otherwise ignore
1596 /* In that case, we're not stopped in a fork syscall and don't
1597 need this glibc bug workaround. */
1598 info
->need_stale_parent_threads_check
= 0;
1600 if (target_has_execution
&& thread_db_use_events ())
1602 err
= info
->td_thr_event_enable_p (th_p
, 1);
1604 error (_("Cannot enable thread event reporting for LWP %d: %s"),
1605 (int) ti
.ti_lid
, thread_db_err_str (err
));
1611 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1612 bit expensive, as it needs to open /proc/pid/status, so try to
1613 avoid doing the work if we know we don't have to. */
1614 if (info
->need_stale_parent_threads_check
)
1616 int tgid
= linux_proc_get_tgid (ti
.ti_lid
);
1618 if (tgid
!= -1 && tgid
!= info
->pid
)
1622 ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
1623 tp
= find_thread_ptid (ptid
);
1624 if (tp
== NULL
|| tp
->priv
== NULL
)
1626 if (attach_thread (ptid
, th_p
, &ti
))
1627 cb_data
->new_threads
+= 1;
1629 /* Problem attaching this thread; perhaps it exited before we
1631 This could mean that the thread list inside glibc itself is in
1632 inconsistent state, and libthread_db could go on looping forever
1633 (observed with glibc-2.3.6). To prevent that, terminate
1634 iteration: thread_db_find_new_threads_2 will retry. */
1637 else if (target_has_execution
&& !thread_db_use_events ())
1639 /* Need to update this if not using the libthread_db events
1640 (particularly, the TD_DEATH event). */
1641 update_thread_state (tp
->priv
, &ti
);
1647 /* Helper for thread_db_find_new_threads_2.
1648 Returns number of new threads found. */
1651 find_new_threads_once (struct thread_db_info
*info
, int iteration
,
1654 struct callback_data data
;
1655 td_err_e err
= TD_ERR
;
1658 data
.new_threads
= 0;
1660 /* See comment in thread_db_update_thread_list. */
1661 gdb_assert (!target_has_execution
|| thread_db_use_events ());
1665 /* Iterate over all user-space threads to discover new threads. */
1666 err
= info
->td_ta_thr_iter_p (info
->thread_agent
,
1667 find_new_threads_callback
,
1670 TD_THR_LOWEST_PRIORITY
,
1672 TD_THR_ANY_USER_FLAGS
);
1674 CATCH (except
, RETURN_MASK_ERROR
)
1676 if (libthread_db_debug
)
1678 exception_fprintf (gdb_stdlog
, except
,
1679 "Warning: find_new_threads_once: ");
1684 if (libthread_db_debug
)
1686 fprintf_unfiltered (gdb_stdlog
,
1687 _("Found %d new threads in iteration %d.\n"),
1688 data
.new_threads
, iteration
);
1694 return data
.new_threads
;
1697 /* Search for new threads, accessing memory through stopped thread
1698 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1699 searches in a row do not discover any new threads. */
1702 thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
)
1704 td_err_e err
= TD_OK
;
1705 struct thread_db_info
*info
;
1708 info
= get_thread_db_info (ptid_get_pid (ptid
));
1710 /* Access an lwp we know is stopped. */
1711 info
->proc_handle
.ptid
= ptid
;
1715 /* Require 4 successive iterations which do not find any new threads.
1716 The 4 is a heuristic: there is an inherent race here, and I have
1717 seen that 2 iterations in a row are not always sufficient to
1718 "capture" all threads. */
1719 for (i
= 0, loop
= 0; loop
< 4 && err
== TD_OK
; ++i
, ++loop
)
1720 if (find_new_threads_once (info
, i
, &err
) != 0)
1722 /* Found some new threads. Restart the loop from beginning. */
1727 find_new_threads_once (info
, 0, &err
);
1730 error (_("Cannot find new threads: %s"), thread_db_err_str (err
));
1734 thread_db_find_new_threads_1 (ptid_t ptid
)
1736 thread_db_find_new_threads_2 (ptid
, 0);
1740 update_thread_core (struct lwp_info
*info
, void *closure
)
1742 info
->core
= linux_common_core_of_thread (info
->ptid
);
1746 /* Update the thread list using td_ta_thr_iter. */
1749 thread_db_update_thread_list_td_ta_thr_iter (struct target_ops
*ops
)
1751 struct thread_db_info
*info
;
1752 struct inferior
*inf
;
1758 struct thread_info
*thread
;
1763 info
= get_thread_db_info (inf
->pid
);
1767 thread
= any_live_thread_of_process (inf
->pid
);
1768 if (thread
== NULL
|| thread
->executing
)
1771 thread_db_find_new_threads_1 (thread
->ptid
);
1775 /* Implement the to_update_thread_list target method for this
1779 thread_db_update_thread_list (struct target_ops
*ops
)
1781 /* It's best to avoid td_ta_thr_iter if possible. That walks data
1782 structures in the inferior's address space that may be corrupted,
1783 or, if the target is running, the list may change while we walk
1784 it. In the latter case, it's possible that a thread exits just
1785 at the exact time that causes GDB to get stuck in an infinite
1786 loop. To avoid pausing all threads whenever the core wants to
1787 refresh the thread list, if the kernel supports clone events
1788 (meaning we're always already attached to all LWPs), we use
1789 thread_from_lwp immediately when we see an LWP stop. That uses
1790 thread_db entry points that do not walk libpthread's thread list,
1791 so should be safe, as well as more efficient. */
1792 if (target_has_execution
&& !thread_db_use_events ())
1793 ops
->beneath
->to_update_thread_list (ops
->beneath
);
1795 thread_db_update_thread_list_td_ta_thr_iter (ops
);
1797 if (target_has_execution
)
1798 iterate_over_lwps (minus_one_ptid
/* iterate over all */,
1799 update_thread_core
, NULL
);
1803 thread_db_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
1805 struct thread_info
*thread_info
= find_thread_ptid (ptid
);
1806 struct target_ops
*beneath
;
1808 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1810 static char buf
[64];
1813 tid
= thread_info
->priv
->tid
;
1814 snprintf (buf
, sizeof (buf
), "Thread 0x%lx (LWP %ld)",
1815 tid
, ptid_get_lwp (ptid
));
1820 beneath
= find_target_beneath (ops
);
1821 return beneath
->to_pid_to_str (beneath
, ptid
);
1824 /* Return a string describing the state of the thread specified by
1828 thread_db_extra_thread_info (struct target_ops
*self
,
1829 struct thread_info
*info
)
1831 if (info
->priv
== NULL
)
1834 if (info
->priv
->dying
)
1840 /* Get the address of the thread local variable in load module LM which
1841 is stored at OFFSET within the thread local storage for thread PTID. */
1844 thread_db_get_thread_local_address (struct target_ops
*ops
,
1849 struct thread_info
*thread_info
;
1850 struct target_ops
*beneath
;
1852 /* Find the matching thread. */
1853 thread_info
= find_thread_ptid (ptid
);
1855 /* We may not have discovered the thread yet. */
1856 if (thread_info
!= NULL
&& thread_info
->priv
== NULL
)
1858 thread_from_lwp (ptid
);
1859 thread_info
= find_thread_ptid (ptid
);
1862 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1866 struct thread_db_info
*info
;
1868 info
= get_thread_db_info (ptid_get_pid (ptid
));
1870 /* Finally, get the address of the variable. */
1873 /* glibc doesn't provide the needed interface. */
1874 if (!info
->td_thr_tls_get_addr_p
)
1875 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR
,
1876 _("No TLS library support"));
1878 /* Note the cast through uintptr_t: this interface only works if
1879 a target address fits in a psaddr_t, which is a host pointer.
1880 So a 32-bit debugger can not access 64-bit TLS through this. */
1881 err
= info
->td_thr_tls_get_addr_p (&thread_info
->priv
->th
,
1882 (psaddr_t
)(uintptr_t) lm
,
1887 /* If glibc doesn't provide the needed interface throw an error
1888 that LM is zero - normally cases it should not be. */
1889 if (!info
->td_thr_tlsbase_p
)
1890 throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR
,
1891 _("TLS load module not found"));
1893 /* This code path handles the case of -static -pthread executables:
1894 https://sourceware.org/ml/libc-help/2014-03/msg00024.html
1895 For older GNU libc r_debug.r_map is NULL. For GNU libc after
1896 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
1897 The constant number 1 depends on GNU __libc_setup_tls
1898 initialization of l_tls_modid to 1. */
1899 err
= info
->td_thr_tlsbase_p (&thread_info
->priv
->th
,
1901 address
= (char *) address
+ offset
;
1904 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1905 /* The memory hasn't been allocated, yet. */
1906 if (err
== TD_NOTALLOC
)
1907 /* Now, if libthread_db provided the initialization image's
1908 address, we *could* try to build a non-lvalue value from
1909 the initialization image. */
1910 throw_error (TLS_NOT_ALLOCATED_YET_ERROR
,
1911 _("TLS not allocated yet"));
1914 /* Something else went wrong. */
1916 throw_error (TLS_GENERIC_ERROR
,
1917 (("%s")), thread_db_err_str (err
));
1919 /* Cast assuming host == target. Joy. */
1920 /* Do proper sign extension for the target. */
1921 gdb_assert (exec_bfd
);
1922 return (bfd_get_sign_extend_vma (exec_bfd
) > 0
1923 ? (CORE_ADDR
) (intptr_t) address
1924 : (CORE_ADDR
) (uintptr_t) address
);
1927 beneath
= find_target_beneath (ops
);
1928 return beneath
->to_get_thread_local_address (beneath
, ptid
, lm
, offset
);
1931 /* Implement the to_get_ada_task_ptid target method for this target. */
1934 thread_db_get_ada_task_ptid (struct target_ops
*self
, long lwp
, long thread
)
1936 /* NPTL uses a 1:1 model, so the LWP id suffices. */
1937 return ptid_build (ptid_get_pid (inferior_ptid
), lwp
, 0);
1941 thread_db_resume (struct target_ops
*ops
,
1942 ptid_t ptid
, int step
, enum gdb_signal signo
)
1944 struct target_ops
*beneath
= find_target_beneath (ops
);
1945 struct thread_db_info
*info
;
1947 if (ptid_equal (ptid
, minus_one_ptid
))
1948 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1950 info
= get_thread_db_info (ptid_get_pid (ptid
));
1952 /* This workaround is only needed for child fork lwps stopped in a
1953 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1954 workaround can be disabled. */
1956 info
->need_stale_parent_threads_check
= 0;
1958 beneath
->to_resume (beneath
, ptid
, step
, signo
);
1961 /* qsort helper function for info_auto_load_libthread_db, sort the
1962 thread_db_info pointers primarily by their FILENAME and secondarily by their
1963 PID, both in ascending order. */
1966 info_auto_load_libthread_db_compare (const void *ap
, const void *bp
)
1968 struct thread_db_info
*a
= *(struct thread_db_info
**) ap
;
1969 struct thread_db_info
*b
= *(struct thread_db_info
**) bp
;
1972 retval
= strcmp (a
->filename
, b
->filename
);
1976 return (a
->pid
> b
->pid
) - (a
->pid
- b
->pid
);
1979 /* Implement 'info auto-load libthread-db'. */
1982 info_auto_load_libthread_db (char *args
, int from_tty
)
1984 struct ui_out
*uiout
= current_uiout
;
1985 const char *cs
= args
? args
: "";
1986 struct thread_db_info
*info
, **array
;
1987 unsigned info_count
, unique_filenames
;
1988 size_t max_filename_len
, max_pids_len
, pids_len
;
1989 struct cleanup
*back_to
;
1993 cs
= skip_spaces_const (cs
);
1995 error (_("'info auto-load libthread-db' does not accept any parameters"));
1998 for (info
= thread_db_list
; info
; info
= info
->next
)
1999 if (info
->filename
!= NULL
)
2002 array
= XNEWVEC (struct thread_db_info
*, info_count
);
2003 back_to
= make_cleanup (xfree
, array
);
2006 for (info
= thread_db_list
; info
; info
= info
->next
)
2007 if (info
->filename
!= NULL
)
2008 array
[info_count
++] = info
;
2010 /* Sort ARRAY by filenames and PIDs. */
2012 qsort (array
, info_count
, sizeof (*array
),
2013 info_auto_load_libthread_db_compare
);
2015 /* Calculate the number of unique filenames (rows) and the maximum string
2016 length of PIDs list for the unique filenames (columns). */
2018 unique_filenames
= 0;
2019 max_filename_len
= 0;
2022 for (i
= 0; i
< info_count
; i
++)
2024 int pid
= array
[i
]->pid
;
2025 size_t this_pid_len
;
2027 for (this_pid_len
= 0; pid
!= 0; pid
/= 10)
2030 if (i
== 0 || strcmp (array
[i
- 1]->filename
, array
[i
]->filename
) != 0)
2033 max_filename_len
= max (max_filename_len
,
2034 strlen (array
[i
]->filename
));
2038 pids_len
-= strlen (", ");
2039 max_pids_len
= max (max_pids_len
, pids_len
);
2043 pids_len
+= this_pid_len
+ strlen (", ");
2047 pids_len
-= strlen (", ");
2048 max_pids_len
= max (max_pids_len
, pids_len
);
2051 /* Table header shifted right by preceding "libthread-db: " would not match
2053 if (info_count
> 0 && args
== auto_load_info_scripts_pattern_nl
)
2054 ui_out_text (uiout
, "\n");
2056 make_cleanup_ui_out_table_begin_end (uiout
, 2, unique_filenames
,
2057 "LinuxThreadDbTable");
2059 ui_out_table_header (uiout
, max_filename_len
, ui_left
, "filename",
2061 ui_out_table_header (uiout
, pids_len
, ui_left
, "PIDs", "Pids");
2062 ui_out_table_body (uiout
);
2064 pids
= xmalloc (max_pids_len
+ 1);
2065 make_cleanup (xfree
, pids
);
2067 /* Note I is incremented inside the cycle, not at its end. */
2068 for (i
= 0; i
< info_count
;)
2070 struct cleanup
*chain
= make_cleanup_ui_out_tuple_begin_end (uiout
, NULL
);
2074 ui_out_field_string (uiout
, "filename", info
->filename
);
2077 while (i
< info_count
&& strcmp (info
->filename
, array
[i
]->filename
) == 0)
2079 if (pids_end
!= pids
)
2084 pids_end
+= xsnprintf (pids_end
, &pids
[max_pids_len
+ 1] - pids_end
,
2085 "%u", array
[i
]->pid
);
2086 gdb_assert (pids_end
< &pids
[max_pids_len
+ 1]);
2092 ui_out_field_string (uiout
, "pids", pids
);
2094 ui_out_text (uiout
, "\n");
2095 do_cleanups (chain
);
2098 do_cleanups (back_to
);
2100 if (info_count
== 0)
2101 ui_out_message (uiout
, 0, _("No auto-loaded libthread-db.\n"));
2105 init_thread_db_ops (void)
2107 thread_db_ops
.to_shortname
= "multi-thread";
2108 thread_db_ops
.to_longname
= "multi-threaded child process.";
2109 thread_db_ops
.to_doc
= "Threads and pthreads support.";
2110 thread_db_ops
.to_detach
= thread_db_detach
;
2111 thread_db_ops
.to_wait
= thread_db_wait
;
2112 thread_db_ops
.to_resume
= thread_db_resume
;
2113 thread_db_ops
.to_mourn_inferior
= thread_db_mourn_inferior
;
2114 thread_db_ops
.to_update_thread_list
= thread_db_update_thread_list
;
2115 thread_db_ops
.to_pid_to_str
= thread_db_pid_to_str
;
2116 thread_db_ops
.to_stratum
= thread_stratum
;
2117 thread_db_ops
.to_has_thread_control
= tc_schedlock
;
2118 thread_db_ops
.to_get_thread_local_address
2119 = thread_db_get_thread_local_address
;
2120 thread_db_ops
.to_extra_thread_info
= thread_db_extra_thread_info
;
2121 thread_db_ops
.to_get_ada_task_ptid
= thread_db_get_ada_task_ptid
;
2122 thread_db_ops
.to_magic
= OPS_MAGIC
;
2124 complete_target_initialization (&thread_db_ops
);
2127 /* Provide a prototype to silence -Wmissing-prototypes. */
2128 extern initialize_file_ftype _initialize_thread_db
;
2131 _initialize_thread_db (void)
2133 init_thread_db_ops ();
2135 /* Defer loading of libthread_db.so until inferior is running.
2136 This allows gdb to load correct libthread_db for a given
2137 executable -- there could be mutiple versions of glibc,
2138 compiled with LinuxThreads or NPTL, and until there is
2139 a running inferior, we can't tell which libthread_db is
2140 the correct one to load. */
2142 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
2144 add_setshow_optional_filename_cmd ("libthread-db-search-path",
2146 &libthread_db_search_path
, _("\
2147 Set search path for libthread_db."), _("\
2148 Show the current search path or libthread_db."), _("\
2149 This path is used to search for libthread_db to be loaded into \
2151 Its value is a colon (':') separate list of directories to search.\n\
2152 Setting the search path to an empty list resets it to its default value."),
2153 set_libthread_db_search_path
,
2155 &setlist
, &showlist
);
2157 add_setshow_zuinteger_cmd ("libthread-db", class_maintenance
,
2158 &libthread_db_debug
, _("\
2159 Set libthread-db debugging."), _("\
2160 Show libthread-db debugging."), _("\
2161 When non-zero, libthread-db debugging is enabled."),
2163 show_libthread_db_debug
,
2164 &setdebuglist
, &showdebuglist
);
2166 add_setshow_boolean_cmd ("libthread-db", class_support
,
2167 &auto_load_thread_db
, _("\
2168 Enable or disable auto-loading of inferior specific libthread_db."), _("\
2169 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
2170 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
2171 locations to load libthread_db compatible with the inferior.\n\
2172 Standard system libthread_db still gets loaded even with this option off.\n\
2173 This options has security implications for untrusted inferiors."),
2174 NULL
, show_auto_load_thread_db
,
2175 auto_load_set_cmdlist_get (),
2176 auto_load_show_cmdlist_get ());
2178 add_cmd ("libthread-db", class_info
, info_auto_load_libthread_db
,
2179 _("Print the list of loaded inferior specific libthread_db.\n\
2180 Usage: info auto-load libthread-db"),
2181 auto_load_info_cmdlist_get ());
2183 /* Add ourselves to objfile event chain. */
2184 observer_attach_new_objfile (thread_db_new_objfile
);
2186 /* Add ourselves to inferior_created event chain.
2187 This is needed to handle debugging statically linked programs where
2188 the new_objfile observer won't get called for libpthread. */
2189 observer_attach_inferior_created (thread_db_inferior_created
);