1 /* libthread_db assisted debugging support, generic parts.
3 Copyright (C) 1999-2016 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 both
58 more powerful and more complicated. This implementation only works
59 for NPTL, the glibc threading library. It assumes that each thread
60 is permanently assigned to a single light-weight process (LWP). At
61 some point it also supported the older LinuxThreads library, but it
64 libthread_db-specific information is stored in the "private" field
65 of struct thread_info. When the field is NULL we do not yet have
66 information about the new thread; this could be temporary (created,
67 but the thread library's data structures do not reflect it yet)
68 or permanent (created using clone instead of pthread_create).
70 Process IDs managed by linux-thread-db.c match those used by
71 linux-nat.c: a common PID for all processes, an LWP ID for each
72 thread, and no TID. We save the TID in private. Keeping it out
73 of the ptid_t prevents thread IDs changing when libpthread is
74 loaded or unloaded. */
76 static char *libthread_db_search_path
;
78 /* Set to non-zero if thread_db auto-loading is enabled
79 by the "set auto-load libthread-db" command. */
80 static int auto_load_thread_db
= 1;
82 /* "show" command for the auto_load_thread_db configuration variable. */
85 show_auto_load_thread_db (struct ui_file
*file
, int from_tty
,
86 struct cmd_list_element
*c
, const char *value
)
88 fprintf_filtered (file
, _("Auto-loading of inferior specific libthread_db "
94 set_libthread_db_search_path (char *ignored
, int from_tty
,
95 struct cmd_list_element
*c
)
97 if (*libthread_db_search_path
== '\0')
99 xfree (libthread_db_search_path
);
100 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
104 /* If non-zero, print details of libthread_db processing. */
106 static unsigned int libthread_db_debug
;
109 show_libthread_db_debug (struct ui_file
*file
, int from_tty
,
110 struct cmd_list_element
*c
, const char *value
)
112 fprintf_filtered (file
, _("libthread-db debugging is %s.\n"), value
);
115 /* If we're running on GNU/Linux, we must explicitly attach to any new
118 /* This module's target vector. */
119 static struct target_ops thread_db_ops
;
121 /* Non-zero if we have determined the signals used by the threads
123 static int thread_signals
;
124 static sigset_t thread_stop_set
;
125 static sigset_t thread_print_set
;
127 struct thread_db_info
129 struct thread_db_info
*next
;
131 /* Process id this object refers to. */
134 /* Handle from dlopen for libthread_db.so. */
137 /* Absolute pathname from gdb_realpath to disk file used for dlopen-ing
138 HANDLE. It may be NULL for system library. */
141 /* Structure that identifies the child process for the
142 <proc_service.h> interface. */
143 struct ps_prochandle proc_handle
;
145 /* Connection to the libthread_db library. */
146 td_thragent_t
*thread_agent
;
148 /* True if we need to apply the workaround for glibc/BZ5983. When
149 we catch a PTRACE_O_TRACEFORK, and go query the child's thread
150 list, nptl_db returns the parent's threads in addition to the new
151 (single) child thread. If this flag is set, we do extra work to
152 be able to ignore such stale entries. */
153 int need_stale_parent_threads_check
;
155 /* Pointers to the libthread_db functions. */
157 td_init_ftype
*td_init_p
;
158 td_ta_new_ftype
*td_ta_new_p
;
159 td_ta_map_lwp2thr_ftype
*td_ta_map_lwp2thr_p
;
160 td_ta_thr_iter_ftype
*td_ta_thr_iter_p
;
161 td_thr_get_info_ftype
*td_thr_get_info_p
;
162 td_thr_tls_get_addr_ftype
*td_thr_tls_get_addr_p
;
163 td_thr_tlsbase_ftype
*td_thr_tlsbase_p
;
166 /* List of known processes using thread_db, and the required
168 struct thread_db_info
*thread_db_list
;
170 static void thread_db_find_new_threads_1 (ptid_t ptid
);
171 static void thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
);
173 static void check_thread_signals (void);
175 static struct thread_info
*record_thread
176 (struct thread_db_info
*info
, struct thread_info
*tp
,
177 ptid_t ptid
, const td_thrhandle_t
*th_p
, const td_thrinfo_t
*ti_p
);
179 /* Add the current inferior to the list of processes using libpthread.
180 Return a pointer to the newly allocated object that was added to
181 THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
184 static struct thread_db_info
*
185 add_thread_db_info (void *handle
)
187 struct thread_db_info
*info
= XCNEW (struct thread_db_info
);
189 info
->pid
= ptid_get_pid (inferior_ptid
);
190 info
->handle
= handle
;
192 /* The workaround works by reading from /proc/pid/status, so it is
193 disabled for core files. */
194 if (target_has_execution
)
195 info
->need_stale_parent_threads_check
= 1;
197 info
->next
= thread_db_list
;
198 thread_db_list
= info
;
203 /* Return the thread_db_info object representing the bookkeeping
204 related to process PID, if any; NULL otherwise. */
206 static struct thread_db_info
*
207 get_thread_db_info (int pid
)
209 struct thread_db_info
*info
;
211 for (info
= thread_db_list
; info
; info
= info
->next
)
212 if (pid
== info
->pid
)
218 /* When PID has exited or has been detached, we no longer want to keep
219 track of it as using libpthread. Call this function to discard
220 thread_db related info related to PID. Note that this closes
221 LIBTHREAD_DB_SO's dlopen'ed handle. */
224 delete_thread_db_info (int pid
)
226 struct thread_db_info
*info
, *info_prev
;
230 for (info
= thread_db_list
; info
; info_prev
= info
, info
= info
->next
)
231 if (pid
== info
->pid
)
237 if (info
->handle
!= NULL
)
238 dlclose (info
->handle
);
240 xfree (info
->filename
);
243 info_prev
->next
= info
->next
;
245 thread_db_list
= info
->next
;
250 /* Use "struct private_thread_info" to cache thread state. This is
251 a substantial optimization. */
253 struct private_thread_info
255 /* Flag set when we see a TD_DEATH event for this thread. */
256 unsigned int dying
:1;
258 /* Cached thread state. */
265 thread_db_err_str (td_err_e err
)
272 return "generic 'call succeeded'";
274 return "generic error";
276 return "no thread to satisfy query";
278 return "no sync handle to satisfy query";
280 return "no LWP to satisfy query";
282 return "invalid process handle";
284 return "invalid thread handle";
286 return "invalid synchronization handle";
288 return "invalid thread agent";
290 return "invalid key";
292 return "no event message for getmsg";
294 return "FPU register set not available";
296 return "application not linked with libthread";
298 return "requested event is not supported";
300 return "capability not available";
302 return "debugger service failed";
304 return "operation not applicable to";
306 return "no thread-specific data for this thread";
308 return "malloc failed";
310 return "only part of register set was written/read";
312 return "X register set not available for this thread";
313 #ifdef THREAD_DB_HAS_TD_NOTALLOC
315 return "thread has not yet allocated TLS for given module";
317 #ifdef THREAD_DB_HAS_TD_VERSION
319 return "versions of libpthread and libthread_db do not match";
321 #ifdef THREAD_DB_HAS_TD_NOTLS
323 return "there is no TLS segment in the given module";
326 snprintf (buf
, sizeof (buf
), "unknown thread_db error '%d'", err
);
331 /* Fetch the user-level thread id of PTID. */
333 static struct thread_info
*
334 thread_from_lwp (ptid_t ptid
)
339 struct thread_db_info
*info
;
340 struct thread_info
*tp
;
342 /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
345 /* This ptid comes from linux-nat.c, which should always fill in the
347 gdb_assert (ptid_get_lwp (ptid
) != 0);
349 info
= get_thread_db_info (ptid_get_pid (ptid
));
351 /* Access an lwp we know is stopped. */
352 info
->proc_handle
.ptid
= ptid
;
353 err
= info
->td_ta_map_lwp2thr_p (info
->thread_agent
, ptid_get_lwp (ptid
),
356 error (_("Cannot find user-level thread for LWP %ld: %s"),
357 ptid_get_lwp (ptid
), thread_db_err_str (err
));
359 err
= info
->td_thr_get_info_p (&th
, &ti
);
361 error (_("thread_get_info_callback: cannot get thread info: %s"),
362 thread_db_err_str (err
));
364 /* Fill the cache. */
365 tp
= find_thread_ptid (ptid
);
366 return record_thread (info
, tp
, ptid
, &th
, &ti
);
370 /* See linux-nat.h. */
373 thread_db_notice_clone (ptid_t parent
, ptid_t child
)
375 struct thread_db_info
*info
;
377 info
= get_thread_db_info (ptid_get_pid (child
));
382 thread_from_lwp (child
);
384 /* If we do not know about the main thread yet, this would be a good
386 thread_from_lwp (parent
);
391 verbose_dlsym (void *handle
, const char *name
)
393 void *sym
= dlsym (handle
, name
);
395 warning (_("Symbol \"%s\" not found in libthread_db: %s"),
400 /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
401 return 1 if this version is lower (and not equal) to
402 VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
405 inferior_has_bug (const char *ver_symbol
, int ver_major_min
, int ver_minor_min
)
407 struct bound_minimal_symbol version_msym
;
408 CORE_ADDR version_addr
;
410 int err
, got
, retval
= 0;
412 version_msym
= lookup_minimal_symbol (ver_symbol
, NULL
, NULL
);
413 if (version_msym
.minsym
== NULL
)
416 version_addr
= BMSYMBOL_VALUE_ADDRESS (version_msym
);
417 got
= target_read_string (version_addr
, &version
, 32, &err
);
418 if (err
== 0 && memchr (version
, 0, got
) == &version
[got
-1])
422 retval
= (sscanf (version
, "%d.%d", &major
, &minor
) == 2
423 && (major
< ver_major_min
424 || (major
== ver_major_min
&& minor
< ver_minor_min
)));
431 /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
434 Return 1 if the caller should abort libthread_db initialization. Return 0
438 thread_db_find_new_threads_silently (ptid_t ptid
)
443 thread_db_find_new_threads_2 (ptid
, 1);
446 CATCH (except
, RETURN_MASK_ERROR
)
448 if (libthread_db_debug
)
449 exception_fprintf (gdb_stdlog
, except
,
450 "Warning: thread_db_find_new_threads_silently: ");
452 /* There is a bug fixed between nptl 2.6.1 and 2.7 by
453 commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
454 where calls to td_thr_get_info fail with TD_ERR for statically linked
455 executables if td_thr_get_info is called before glibc has initialized
458 If the nptl bug is NOT present in the inferior and still thread_db
459 reports an error return 1. It means the inferior has corrupted thread
460 list and GDB should fall back only to LWPs.
462 If the nptl bug is present in the inferior return 0 to silently ignore
463 such errors, and let gdb enumerate threads again later. In such case
464 GDB cannot properly display LWPs if the inferior thread list is
465 corrupted. For core files it does not apply, no 'later enumeration'
468 if (!target_has_execution
|| !inferior_has_bug ("nptl_version", 2, 7))
470 exception_fprintf (gdb_stderr
, except
,
471 _("Warning: couldn't activate thread debugging "
472 "using libthread_db: "));
481 /* Lookup a library in which given symbol resides.
482 Note: this is looking in GDB process, not in the inferior.
483 Returns library name, or NULL. */
486 dladdr_to_soname (const void *addr
)
490 if (dladdr (addr
, &info
) != 0)
491 return info
.dli_fname
;
495 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
497 Failure could happen if libthread_db does not have symbols we expect,
498 or when it refuses to work with the current inferior (e.g. due to
499 version mismatch between libthread_db and libpthread). */
502 try_thread_db_load_1 (struct thread_db_info
*info
)
506 /* Initialize pointers to the dynamic library functions we will use.
507 Essential functions first. */
509 #define TDB_VERBOSE_DLSYM(info, func) \
510 info->func ## _p = (func ## _ftype *) verbose_dlsym (info->handle, #func)
512 #define TDB_DLSYM(info, func) \
513 info->func ## _p = (func ## _ftype *) dlsym (info->handle, #func)
522 CHK (TDB_VERBOSE_DLSYM (info
, td_init
));
524 err
= info
->td_init_p ();
527 warning (_("Cannot initialize libthread_db: %s"),
528 thread_db_err_str (err
));
532 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_new
));
534 /* Initialize the structure that identifies the child process. */
535 info
->proc_handle
.ptid
= inferior_ptid
;
537 /* Now attempt to open a connection to the thread library. */
538 err
= info
->td_ta_new_p (&info
->proc_handle
, &info
->thread_agent
);
541 if (libthread_db_debug
)
542 fprintf_unfiltered (gdb_stdlog
, _("td_ta_new failed: %s\n"),
543 thread_db_err_str (err
));
548 #ifdef THREAD_DB_HAS_TD_VERSION
551 /* The errors above are not unexpected and silently ignored:
552 they just mean we haven't found correct version of
556 warning (_("td_ta_new failed: %s"), thread_db_err_str (err
));
561 /* These are essential. */
562 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_map_lwp2thr
));
563 CHK (TDB_VERBOSE_DLSYM (info
, td_thr_get_info
));
565 /* These are not essential. */
566 TDB_DLSYM (info
, td_thr_tls_get_addr
);
567 TDB_DLSYM (info
, td_thr_tlsbase
);
569 /* It's best to avoid td_ta_thr_iter if possible. That walks data
570 structures in the inferior's address space that may be corrupted,
571 or, if the target is running, may change while we walk them. If
572 there's execution (and /proc is mounted), then we're already
573 attached to all LWPs. Use thread_from_lwp, which uses
574 td_ta_map_lwp2thr instead, which does not walk the thread list.
576 td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that
577 currently on core targets, as it uses ptrace directly. */
578 if (target_has_execution
579 && linux_proc_task_list_dir_exists (ptid_get_pid (inferior_ptid
)))
580 info
->td_ta_thr_iter_p
= NULL
;
582 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_thr_iter
));
584 #undef TDB_VERBOSE_DLSYM
588 if (info
->td_ta_thr_iter_p
== NULL
)
591 int pid
= ptid_get_pid (inferior_ptid
);
593 linux_stop_and_wait_all_lwps ();
596 if (ptid_get_pid (lp
->ptid
) == pid
)
597 thread_from_lwp (lp
->ptid
);
599 linux_unstop_all_lwps ();
601 else if (thread_db_find_new_threads_silently (inferior_ptid
) != 0)
603 /* Even if libthread_db initializes, if the thread list is
604 corrupted, we'd not manage to list any threads. Better reject this
605 thread_db, and fall back to at least listing LWPs. */
609 printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
611 if (*libthread_db_search_path
|| libthread_db_debug
)
613 struct ui_file
*file
;
616 library
= dladdr_to_soname ((const void *) *info
->td_ta_new_p
);
618 library
= LIBTHREAD_DB_SO
;
620 /* If we'd print this to gdb_stdout when debug output is
621 disabled, still print it to gdb_stdout if debug output is
622 enabled. User visible output should not depend on debug
624 file
= *libthread_db_search_path
!= '\0' ? gdb_stdout
: gdb_stdlog
;
625 fprintf_unfiltered (file
, _("Using host libthread_db library \"%s\".\n"),
629 /* The thread library was detected. Activate the thread_db target
630 if this is the first process using it. */
631 if (thread_db_list
->next
== NULL
)
632 push_target (&thread_db_ops
);
637 /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
638 relative, or just LIBTHREAD_DB. */
641 try_thread_db_load (const char *library
, int check_auto_load_safe
)
644 struct thread_db_info
*info
;
646 if (libthread_db_debug
)
647 fprintf_unfiltered (gdb_stdlog
,
648 _("Trying host libthread_db library: %s.\n"),
651 if (check_auto_load_safe
)
653 if (access (library
, R_OK
) != 0)
655 /* Do not print warnings by file_is_auto_load_safe if the library does
656 not exist at this place. */
657 if (libthread_db_debug
)
658 fprintf_unfiltered (gdb_stdlog
, _("open failed: %s.\n"),
659 safe_strerror (errno
));
663 if (!file_is_auto_load_safe (library
, _("auto-load: Loading libthread-db "
664 "library \"%s\" from explicit "
670 handle
= dlopen (library
, RTLD_NOW
);
673 if (libthread_db_debug
)
674 fprintf_unfiltered (gdb_stdlog
, _("dlopen failed: %s.\n"), dlerror ());
678 if (libthread_db_debug
&& strchr (library
, '/') == NULL
)
682 td_init
= dlsym (handle
, "td_init");
685 const char *const libpath
= dladdr_to_soname (td_init
);
688 fprintf_unfiltered (gdb_stdlog
, _("Host %s resolved to: %s.\n"),
693 info
= add_thread_db_info (handle
);
695 /* Do not save system library name, that one is always trusted. */
696 if (strchr (library
, '/') != NULL
)
697 info
->filename
= gdb_realpath (library
);
699 if (try_thread_db_load_1 (info
))
702 /* This library "refused" to work on current inferior. */
703 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
707 /* Subroutine of try_thread_db_load_from_pdir to simplify it.
708 Try loading libthread_db in directory(OBJ)/SUBDIR.
709 SUBDIR may be NULL. It may also be something like "../lib64".
710 The result is true for success. */
713 try_thread_db_load_from_pdir_1 (struct objfile
*obj
, const char *subdir
)
715 struct cleanup
*cleanup
;
718 const char *obj_name
= objfile_name (obj
);
721 if (obj_name
[0] != '/')
723 warning (_("Expected absolute pathname for libpthread in the"
724 " inferior, but got %s."), obj_name
);
728 alloc_len
= (strlen (obj_name
)
729 + (subdir
? strlen (subdir
) + 1 : 0)
730 + 1 + strlen (LIBTHREAD_DB_SO
) + 1);
731 path
= (char *) xmalloc (alloc_len
);
732 cleanup
= make_cleanup (xfree
, path
);
734 strcpy (path
, obj_name
);
735 cp
= strrchr (path
, '/');
736 /* This should at minimum hit the first character. */
737 gdb_assert (cp
!= NULL
);
744 strcat (cp
, LIBTHREAD_DB_SO
);
746 result
= try_thread_db_load (path
, 1);
748 do_cleanups (cleanup
);
752 /* Handle $pdir in libthread-db-search-path.
753 Look for libthread_db in directory(libpthread)/SUBDIR.
754 SUBDIR may be NULL. It may also be something like "../lib64".
755 The result is true for success. */
758 try_thread_db_load_from_pdir (const char *subdir
)
762 if (!auto_load_thread_db
)
766 if (libpthread_name_p (objfile_name (obj
)))
768 if (try_thread_db_load_from_pdir_1 (obj
, subdir
))
771 /* We may have found the separate-debug-info version of
772 libpthread, and it may live in a directory without a matching
774 if (obj
->separate_debug_objfile_backlink
!= NULL
)
775 return try_thread_db_load_from_pdir_1 (obj
->separate_debug_objfile_backlink
,
784 /* Handle $sdir in libthread-db-search-path.
785 Look for libthread_db in the system dirs, or wherever a plain
786 dlopen(file_without_path) will look.
787 The result is true for success. */
790 try_thread_db_load_from_sdir (void)
792 return try_thread_db_load (LIBTHREAD_DB_SO
, 0);
795 /* Try to load libthread_db from directory DIR of length DIR_LEN.
796 The result is true for success. */
799 try_thread_db_load_from_dir (const char *dir
, size_t dir_len
)
801 struct cleanup
*cleanup
;
805 if (!auto_load_thread_db
)
808 path
= (char *) xmalloc (dir_len
+ 1 + strlen (LIBTHREAD_DB_SO
) + 1);
809 cleanup
= make_cleanup (xfree
, path
);
811 memcpy (path
, dir
, dir_len
);
813 strcpy (path
+ dir_len
+ 1, LIBTHREAD_DB_SO
);
815 result
= try_thread_db_load (path
, 1);
817 do_cleanups (cleanup
);
821 /* Search libthread_db_search_path for libthread_db which "agrees"
822 to work on current inferior.
823 The result is true for success. */
826 thread_db_load_search (void)
828 VEC (char_ptr
) *dir_vec
;
829 struct cleanup
*cleanups
;
833 dir_vec
= dirnames_to_char_ptr_vec (libthread_db_search_path
);
834 cleanups
= make_cleanup_free_char_ptr_vec (dir_vec
);
836 for (i
= 0; VEC_iterate (char_ptr
, dir_vec
, i
, this_dir
); ++i
)
838 const int pdir_len
= sizeof ("$pdir") - 1;
841 this_dir_len
= strlen (this_dir
);
843 if (strncmp (this_dir
, "$pdir", pdir_len
) == 0
844 && (this_dir
[pdir_len
] == '\0'
845 || this_dir
[pdir_len
] == '/'))
848 struct cleanup
*free_subdir_cleanup
849 = make_cleanup (null_cleanup
, NULL
);
851 if (this_dir
[pdir_len
] == '/')
853 subdir
= (char *) xmalloc (strlen (this_dir
));
854 make_cleanup (xfree
, subdir
);
855 strcpy (subdir
, this_dir
+ pdir_len
+ 1);
857 rc
= try_thread_db_load_from_pdir (subdir
);
858 do_cleanups (free_subdir_cleanup
);
862 else if (strcmp (this_dir
, "$sdir") == 0)
864 if (try_thread_db_load_from_sdir ())
872 if (try_thread_db_load_from_dir (this_dir
, this_dir_len
))
880 do_cleanups (cleanups
);
881 if (libthread_db_debug
)
882 fprintf_unfiltered (gdb_stdlog
,
883 _("thread_db_load_search returning %d\n"), rc
);
887 /* Return non-zero if the inferior has a libpthread. */
890 has_libpthread (void)
895 if (libpthread_name_p (objfile_name (obj
)))
901 /* Attempt to load and initialize libthread_db.
902 Return 1 on success. */
905 thread_db_load (void)
907 struct thread_db_info
*info
;
909 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
914 /* Don't attempt to use thread_db on executables not running
916 if (!target_has_registers
)
919 /* Don't attempt to use thread_db for remote targets. */
920 if (!(target_can_run (¤t_target
) || core_bfd
))
923 if (thread_db_load_search ())
926 /* We couldn't find a libthread_db.
927 If the inferior has a libpthread warn the user. */
928 if (has_libpthread ())
930 warning (_("Unable to find libthread_db matching inferior's thread"
931 " library, thread debugging will not be available."));
935 /* Either this executable isn't using libpthread at all, or it is
936 statically linked. Since we can't easily distinguish these two cases,
937 no warning is issued. */
942 check_thread_signals (void)
949 lin_thread_get_thread_signals (&mask
);
950 sigemptyset (&thread_stop_set
);
951 sigemptyset (&thread_print_set
);
953 for (i
= 1; i
< NSIG
; i
++)
955 if (sigismember (&mask
, i
))
957 if (signal_stop_update (gdb_signal_from_host (i
), 0))
958 sigaddset (&thread_stop_set
, i
);
959 if (signal_print_update (gdb_signal_from_host (i
), 0))
960 sigaddset (&thread_print_set
, i
);
967 /* Check whether thread_db is usable. This function is called when
968 an inferior is created (or otherwise acquired, e.g. attached to)
969 and when new shared libraries are loaded into a running process. */
972 check_for_thread_db (void)
974 /* Do nothing if we couldn't load libthread_db.so.1. */
975 if (!thread_db_load ())
979 /* This function is called via the new_objfile observer. */
982 thread_db_new_objfile (struct objfile
*objfile
)
984 /* This observer must always be called with inferior_ptid set
988 /* libpthread with separate debug info has its debug info file already
989 loaded (and notified without successful thread_db initialization)
990 the time observer_notify_new_objfile is called for the library itself.
991 Static executables have their separate debug info loaded already
992 before the inferior has started. */
993 && objfile
->separate_debug_objfile_backlink
== NULL
994 /* Only check for thread_db if we loaded libpthread,
995 or if this is the main symbol file.
996 We need to check OBJF_MAINLINE to handle the case of debugging
997 a statically linked executable AND the symbol file is specified AFTER
998 the exec file is loaded (e.g., gdb -c core ; file foo).
999 For dynamically linked executables, libpthread can be near the end
1000 of the list of shared libraries to load, and in an app of several
1001 thousand shared libraries, this can otherwise be painful. */
1002 && ((objfile
->flags
& OBJF_MAINLINE
) != 0
1003 || libpthread_name_p (objfile_name (objfile
))))
1004 check_for_thread_db ();
1008 check_pid_namespace_match (void)
1010 /* Check is only relevant for local targets targets. */
1011 if (target_can_run (¤t_target
))
1013 /* If the child is in a different PID namespace, its idea of its
1014 PID will differ from our idea of its PID. When we scan the
1015 child's thread list, we'll mistakenly think it has no threads
1016 since the thread PID fields won't match the PID we give to
1018 if (!linux_ns_same (ptid_get_pid (inferior_ptid
), LINUX_NS_PID
))
1020 warning (_ ("Target and debugger are in different PID "
1021 "namespaces; thread lists and other data are "
1022 "likely unreliable. "
1023 "Connect to gdbserver inside the container."));
1028 /* This function is called via the inferior_created observer.
1029 This handles the case of debugging statically linked executables. */
1032 thread_db_inferior_created (struct target_ops
*target
, int from_tty
)
1034 check_pid_namespace_match ();
1035 check_for_thread_db ();
1038 /* Update the thread's state (what's displayed in "info threads"),
1039 from libthread_db thread state information. */
1042 update_thread_state (struct private_thread_info
*priv
,
1043 const td_thrinfo_t
*ti_p
)
1045 priv
->dying
= (ti_p
->ti_state
== TD_THR_UNKNOWN
1046 || ti_p
->ti_state
== TD_THR_ZOMBIE
);
1049 /* Record a new thread in GDB's thread list. Creates the thread's
1050 private info. If TP is NULL or TP is marked as having exited,
1051 creates a new thread. Otherwise, uses TP. */
1053 static struct thread_info
*
1054 record_thread (struct thread_db_info
*info
,
1055 struct thread_info
*tp
,
1056 ptid_t ptid
, const td_thrhandle_t
*th_p
,
1057 const td_thrinfo_t
*ti_p
)
1059 struct private_thread_info
*priv
;
1061 /* A thread ID of zero may mean the thread library has not
1062 initialized yet. Leave private == NULL until the thread library
1064 if (ti_p
->ti_tid
== 0)
1067 /* Construct the thread's private data. */
1068 priv
= XCNEW (struct private_thread_info
);
1071 priv
->tid
= ti_p
->ti_tid
;
1072 update_thread_state (priv
, ti_p
);
1074 /* Add the thread to GDB's thread list. If we already know about a
1075 thread with this PTID, but it's marked exited, then the kernel
1076 reused the tid of an old thread. */
1077 if (tp
== NULL
|| tp
->state
== THREAD_EXITED
)
1078 tp
= add_thread_with_info (ptid
, priv
);
1082 if (target_has_execution
)
1083 check_thread_signals ();
1089 thread_db_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1091 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1092 struct thread_db_info
*info
;
1094 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1097 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1099 target_beneath
->to_detach (target_beneath
, args
, from_tty
);
1101 /* NOTE: From this point on, inferior_ptid is null_ptid. */
1103 /* If there are no more processes using libpthread, detach the
1104 thread_db target ops. */
1105 if (!thread_db_list
)
1106 unpush_target (&thread_db_ops
);
1110 thread_db_wait (struct target_ops
*ops
,
1111 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
1114 struct thread_db_info
*info
;
1115 struct target_ops
*beneath
= find_target_beneath (ops
);
1117 ptid
= beneath
->to_wait (beneath
, ptid
, ourstatus
, options
);
1119 if (ourstatus
->kind
== TARGET_WAITKIND_IGNORE
)
1122 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
1123 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
1126 info
= get_thread_db_info (ptid_get_pid (ptid
));
1128 /* If this process isn't using thread_db, we're done. */
1132 if (ourstatus
->kind
== TARGET_WAITKIND_EXECD
)
1134 /* New image, it may or may not end up using thread_db. Assume
1135 not unless we find otherwise. */
1136 delete_thread_db_info (ptid_get_pid (ptid
));
1137 if (!thread_db_list
)
1138 unpush_target (&thread_db_ops
);
1143 /* Fill in the thread's user-level thread id and status. */
1144 thread_from_lwp (ptid
);
1150 thread_db_mourn_inferior (struct target_ops
*ops
)
1152 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1154 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1156 target_beneath
->to_mourn_inferior (target_beneath
);
1158 /* Detach thread_db target ops. */
1159 if (!thread_db_list
)
1160 unpush_target (ops
);
1163 struct callback_data
1165 struct thread_db_info
*info
;
1170 find_new_threads_callback (const td_thrhandle_t
*th_p
, void *data
)
1175 struct thread_info
*tp
;
1176 struct callback_data
*cb_data
= (struct callback_data
*) data
;
1177 struct thread_db_info
*info
= cb_data
->info
;
1179 err
= info
->td_thr_get_info_p (th_p
, &ti
);
1181 error (_("find_new_threads_callback: cannot get thread info: %s"),
1182 thread_db_err_str (err
));
1184 if (ti
.ti_lid
== -1)
1186 /* A thread with kernel thread ID -1 is either a thread that
1187 exited and was joined, or a thread that is being created but
1188 hasn't started yet, and that is reusing the tcb/stack of a
1189 thread that previously exited and was joined. (glibc marks
1190 terminated and joined threads with kernel thread ID -1. See
1192 if (libthread_db_debug
)
1193 fprintf_unfiltered (gdb_stdlog
,
1194 "thread_db: skipping exited and "
1195 "joined thread (0x%lx)\n",
1196 (unsigned long) ti
.ti_tid
);
1202 /* A thread ID of zero means that this is the main thread, but
1203 glibc has not yet initialized thread-local storage and the
1204 pthread library. We do not know what the thread's TID will
1207 /* In that case, we're not stopped in a fork syscall and don't
1208 need this glibc bug workaround. */
1209 info
->need_stale_parent_threads_check
= 0;
1214 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1215 bit expensive, as it needs to open /proc/pid/status, so try to
1216 avoid doing the work if we know we don't have to. */
1217 if (info
->need_stale_parent_threads_check
)
1219 int tgid
= linux_proc_get_tgid (ti
.ti_lid
);
1221 if (tgid
!= -1 && tgid
!= info
->pid
)
1225 ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
1226 tp
= find_thread_ptid (ptid
);
1227 if (tp
== NULL
|| tp
->priv
== NULL
)
1228 record_thread (info
, tp
, ptid
, th_p
, &ti
);
1233 /* Helper for thread_db_find_new_threads_2.
1234 Returns number of new threads found. */
1237 find_new_threads_once (struct thread_db_info
*info
, int iteration
,
1240 struct callback_data data
;
1241 td_err_e err
= TD_ERR
;
1244 data
.new_threads
= 0;
1246 /* See comment in thread_db_update_thread_list. */
1247 gdb_assert (info
->td_ta_thr_iter_p
!= NULL
);
1251 /* Iterate over all user-space threads to discover new threads. */
1252 err
= info
->td_ta_thr_iter_p (info
->thread_agent
,
1253 find_new_threads_callback
,
1256 TD_THR_LOWEST_PRIORITY
,
1258 TD_THR_ANY_USER_FLAGS
);
1260 CATCH (except
, RETURN_MASK_ERROR
)
1262 if (libthread_db_debug
)
1264 exception_fprintf (gdb_stdlog
, except
,
1265 "Warning: find_new_threads_once: ");
1270 if (libthread_db_debug
)
1272 fprintf_unfiltered (gdb_stdlog
,
1273 _("Found %d new threads in iteration %d.\n"),
1274 data
.new_threads
, iteration
);
1280 return data
.new_threads
;
1283 /* Search for new threads, accessing memory through stopped thread
1284 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1285 searches in a row do not discover any new threads. */
1288 thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
)
1290 td_err_e err
= TD_OK
;
1291 struct thread_db_info
*info
;
1294 info
= get_thread_db_info (ptid_get_pid (ptid
));
1296 /* Access an lwp we know is stopped. */
1297 info
->proc_handle
.ptid
= ptid
;
1301 /* Require 4 successive iterations which do not find any new threads.
1302 The 4 is a heuristic: there is an inherent race here, and I have
1303 seen that 2 iterations in a row are not always sufficient to
1304 "capture" all threads. */
1305 for (i
= 0, loop
= 0; loop
< 4 && err
== TD_OK
; ++i
, ++loop
)
1306 if (find_new_threads_once (info
, i
, &err
) != 0)
1308 /* Found some new threads. Restart the loop from beginning. */
1313 find_new_threads_once (info
, 0, &err
);
1316 error (_("Cannot find new threads: %s"), thread_db_err_str (err
));
1320 thread_db_find_new_threads_1 (ptid_t ptid
)
1322 thread_db_find_new_threads_2 (ptid
, 0);
1325 /* Implement the to_update_thread_list target method for this
1329 thread_db_update_thread_list (struct target_ops
*ops
)
1331 struct thread_db_info
*info
;
1332 struct inferior
*inf
;
1338 struct thread_info
*thread
;
1343 info
= get_thread_db_info (inf
->pid
);
1347 thread
= any_live_thread_of_process (inf
->pid
);
1348 if (thread
== NULL
|| thread
->executing
)
1351 /* It's best to avoid td_ta_thr_iter if possible. That walks
1352 data structures in the inferior's address space that may be
1353 corrupted, or, if the target is running, the list may change
1354 while we walk it. In the latter case, it's possible that a
1355 thread exits just at the exact time that causes GDB to get
1356 stuck in an infinite loop. To avoid pausing all threads
1357 whenever the core wants to refresh the thread list, we
1358 instead use thread_from_lwp immediately when we see an LWP
1359 stop. That uses thread_db entry points that do not walk
1360 libpthread's thread list, so should be safe, as well as more
1362 if (target_has_execution_1 (thread
->ptid
))
1365 thread_db_find_new_threads_1 (thread
->ptid
);
1368 /* Give the beneath target a chance to do extra processing. */
1369 ops
->beneath
->to_update_thread_list (ops
->beneath
);
1373 thread_db_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
1375 struct thread_info
*thread_info
= find_thread_ptid (ptid
);
1376 struct target_ops
*beneath
;
1378 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1380 static char buf
[64];
1383 tid
= thread_info
->priv
->tid
;
1384 snprintf (buf
, sizeof (buf
), "Thread 0x%lx (LWP %ld)",
1385 (unsigned long) tid
, ptid_get_lwp (ptid
));
1390 beneath
= find_target_beneath (ops
);
1391 return beneath
->to_pid_to_str (beneath
, ptid
);
1394 /* Return a string describing the state of the thread specified by
1398 thread_db_extra_thread_info (struct target_ops
*self
,
1399 struct thread_info
*info
)
1401 if (info
->priv
== NULL
)
1404 if (info
->priv
->dying
)
1410 /* Get the address of the thread local variable in load module LM which
1411 is stored at OFFSET within the thread local storage for thread PTID. */
1414 thread_db_get_thread_local_address (struct target_ops
*ops
,
1419 struct thread_info
*thread_info
;
1420 struct target_ops
*beneath
;
1422 /* Find the matching thread. */
1423 thread_info
= find_thread_ptid (ptid
);
1425 /* We may not have discovered the thread yet. */
1426 if (thread_info
!= NULL
&& thread_info
->priv
== NULL
)
1427 thread_info
= thread_from_lwp (ptid
);
1429 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1433 struct thread_db_info
*info
;
1435 info
= get_thread_db_info (ptid_get_pid (ptid
));
1437 /* Finally, get the address of the variable. */
1440 /* glibc doesn't provide the needed interface. */
1441 if (!info
->td_thr_tls_get_addr_p
)
1442 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR
,
1443 _("No TLS library support"));
1445 /* Note the cast through uintptr_t: this interface only works if
1446 a target address fits in a psaddr_t, which is a host pointer.
1447 So a 32-bit debugger can not access 64-bit TLS through this. */
1448 err
= info
->td_thr_tls_get_addr_p (&thread_info
->priv
->th
,
1449 (psaddr_t
)(uintptr_t) lm
,
1454 /* If glibc doesn't provide the needed interface throw an error
1455 that LM is zero - normally cases it should not be. */
1456 if (!info
->td_thr_tlsbase_p
)
1457 throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR
,
1458 _("TLS load module not found"));
1460 /* This code path handles the case of -static -pthread executables:
1461 https://sourceware.org/ml/libc-help/2014-03/msg00024.html
1462 For older GNU libc r_debug.r_map is NULL. For GNU libc after
1463 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
1464 The constant number 1 depends on GNU __libc_setup_tls
1465 initialization of l_tls_modid to 1. */
1466 err
= info
->td_thr_tlsbase_p (&thread_info
->priv
->th
,
1468 address
= (char *) address
+ offset
;
1471 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1472 /* The memory hasn't been allocated, yet. */
1473 if (err
== TD_NOTALLOC
)
1474 /* Now, if libthread_db provided the initialization image's
1475 address, we *could* try to build a non-lvalue value from
1476 the initialization image. */
1477 throw_error (TLS_NOT_ALLOCATED_YET_ERROR
,
1478 _("TLS not allocated yet"));
1481 /* Something else went wrong. */
1483 throw_error (TLS_GENERIC_ERROR
,
1484 (("%s")), thread_db_err_str (err
));
1486 /* Cast assuming host == target. Joy. */
1487 /* Do proper sign extension for the target. */
1488 gdb_assert (exec_bfd
);
1489 return (bfd_get_sign_extend_vma (exec_bfd
) > 0
1490 ? (CORE_ADDR
) (intptr_t) address
1491 : (CORE_ADDR
) (uintptr_t) address
);
1494 beneath
= find_target_beneath (ops
);
1495 return beneath
->to_get_thread_local_address (beneath
, ptid
, lm
, offset
);
1498 /* Implement the to_get_ada_task_ptid target method for this target. */
1501 thread_db_get_ada_task_ptid (struct target_ops
*self
, long lwp
, long thread
)
1503 /* NPTL uses a 1:1 model, so the LWP id suffices. */
1504 return ptid_build (ptid_get_pid (inferior_ptid
), lwp
, 0);
1508 thread_db_resume (struct target_ops
*ops
,
1509 ptid_t ptid
, int step
, enum gdb_signal signo
)
1511 struct target_ops
*beneath
= find_target_beneath (ops
);
1512 struct thread_db_info
*info
;
1514 if (ptid_equal (ptid
, minus_one_ptid
))
1515 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1517 info
= get_thread_db_info (ptid_get_pid (ptid
));
1519 /* This workaround is only needed for child fork lwps stopped in a
1520 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1521 workaround can be disabled. */
1523 info
->need_stale_parent_threads_check
= 0;
1525 beneath
->to_resume (beneath
, ptid
, step
, signo
);
1528 /* qsort helper function for info_auto_load_libthread_db, sort the
1529 thread_db_info pointers primarily by their FILENAME and secondarily by their
1530 PID, both in ascending order. */
1533 info_auto_load_libthread_db_compare (const void *ap
, const void *bp
)
1535 struct thread_db_info
*a
= *(struct thread_db_info
**) ap
;
1536 struct thread_db_info
*b
= *(struct thread_db_info
**) bp
;
1539 retval
= strcmp (a
->filename
, b
->filename
);
1543 return (a
->pid
> b
->pid
) - (a
->pid
- b
->pid
);
1546 /* Implement 'info auto-load libthread-db'. */
1549 info_auto_load_libthread_db (char *args
, int from_tty
)
1551 struct ui_out
*uiout
= current_uiout
;
1552 const char *cs
= args
? args
: "";
1553 struct thread_db_info
*info
, **array
;
1554 unsigned info_count
, unique_filenames
;
1555 size_t max_filename_len
, max_pids_len
, pids_len
;
1556 struct cleanup
*back_to
;
1560 cs
= skip_spaces_const (cs
);
1562 error (_("'info auto-load libthread-db' does not accept any parameters"));
1565 for (info
= thread_db_list
; info
; info
= info
->next
)
1566 if (info
->filename
!= NULL
)
1569 array
= XNEWVEC (struct thread_db_info
*, info_count
);
1570 back_to
= make_cleanup (xfree
, array
);
1573 for (info
= thread_db_list
; info
; info
= info
->next
)
1574 if (info
->filename
!= NULL
)
1575 array
[info_count
++] = info
;
1577 /* Sort ARRAY by filenames and PIDs. */
1579 qsort (array
, info_count
, sizeof (*array
),
1580 info_auto_load_libthread_db_compare
);
1582 /* Calculate the number of unique filenames (rows) and the maximum string
1583 length of PIDs list for the unique filenames (columns). */
1585 unique_filenames
= 0;
1586 max_filename_len
= 0;
1589 for (i
= 0; i
< info_count
; i
++)
1591 int pid
= array
[i
]->pid
;
1592 size_t this_pid_len
;
1594 for (this_pid_len
= 0; pid
!= 0; pid
/= 10)
1597 if (i
== 0 || strcmp (array
[i
- 1]->filename
, array
[i
]->filename
) != 0)
1600 max_filename_len
= max (max_filename_len
,
1601 strlen (array
[i
]->filename
));
1605 pids_len
-= strlen (", ");
1606 max_pids_len
= max (max_pids_len
, pids_len
);
1610 pids_len
+= this_pid_len
+ strlen (", ");
1614 pids_len
-= strlen (", ");
1615 max_pids_len
= max (max_pids_len
, pids_len
);
1618 /* Table header shifted right by preceding "libthread-db: " would not match
1620 if (info_count
> 0 && args
== auto_load_info_scripts_pattern_nl
)
1621 ui_out_text (uiout
, "\n");
1623 make_cleanup_ui_out_table_begin_end (uiout
, 2, unique_filenames
,
1624 "LinuxThreadDbTable");
1626 ui_out_table_header (uiout
, max_filename_len
, ui_left
, "filename",
1628 ui_out_table_header (uiout
, pids_len
, ui_left
, "PIDs", "Pids");
1629 ui_out_table_body (uiout
);
1631 pids
= (char *) xmalloc (max_pids_len
+ 1);
1632 make_cleanup (xfree
, pids
);
1634 /* Note I is incremented inside the cycle, not at its end. */
1635 for (i
= 0; i
< info_count
;)
1637 struct cleanup
*chain
= make_cleanup_ui_out_tuple_begin_end (uiout
, NULL
);
1641 ui_out_field_string (uiout
, "filename", info
->filename
);
1644 while (i
< info_count
&& strcmp (info
->filename
, array
[i
]->filename
) == 0)
1646 if (pids_end
!= pids
)
1651 pids_end
+= xsnprintf (pids_end
, &pids
[max_pids_len
+ 1] - pids_end
,
1652 "%u", array
[i
]->pid
);
1653 gdb_assert (pids_end
< &pids
[max_pids_len
+ 1]);
1659 ui_out_field_string (uiout
, "pids", pids
);
1661 ui_out_text (uiout
, "\n");
1662 do_cleanups (chain
);
1665 do_cleanups (back_to
);
1667 if (info_count
== 0)
1668 ui_out_message (uiout
, 0, _("No auto-loaded libthread-db.\n"));
1672 init_thread_db_ops (void)
1674 thread_db_ops
.to_shortname
= "multi-thread";
1675 thread_db_ops
.to_longname
= "multi-threaded child process.";
1676 thread_db_ops
.to_doc
= "Threads and pthreads support.";
1677 thread_db_ops
.to_detach
= thread_db_detach
;
1678 thread_db_ops
.to_wait
= thread_db_wait
;
1679 thread_db_ops
.to_resume
= thread_db_resume
;
1680 thread_db_ops
.to_mourn_inferior
= thread_db_mourn_inferior
;
1681 thread_db_ops
.to_update_thread_list
= thread_db_update_thread_list
;
1682 thread_db_ops
.to_pid_to_str
= thread_db_pid_to_str
;
1683 thread_db_ops
.to_stratum
= thread_stratum
;
1684 thread_db_ops
.to_has_thread_control
= tc_schedlock
;
1685 thread_db_ops
.to_get_thread_local_address
1686 = thread_db_get_thread_local_address
;
1687 thread_db_ops
.to_extra_thread_info
= thread_db_extra_thread_info
;
1688 thread_db_ops
.to_get_ada_task_ptid
= thread_db_get_ada_task_ptid
;
1689 thread_db_ops
.to_magic
= OPS_MAGIC
;
1691 complete_target_initialization (&thread_db_ops
);
1694 /* Provide a prototype to silence -Wmissing-prototypes. */
1695 extern initialize_file_ftype _initialize_thread_db
;
1698 _initialize_thread_db (void)
1700 init_thread_db_ops ();
1702 /* Defer loading of libthread_db.so until inferior is running.
1703 This allows gdb to load correct libthread_db for a given
1704 executable -- there could be multiple versions of glibc,
1705 and until there is a running inferior, we can't tell which
1706 libthread_db is the correct one to load. */
1708 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
1710 add_setshow_optional_filename_cmd ("libthread-db-search-path",
1712 &libthread_db_search_path
, _("\
1713 Set search path for libthread_db."), _("\
1714 Show the current search path or libthread_db."), _("\
1715 This path is used to search for libthread_db to be loaded into \
1717 Its value is a colon (':') separate list of directories to search.\n\
1718 Setting the search path to an empty list resets it to its default value."),
1719 set_libthread_db_search_path
,
1721 &setlist
, &showlist
);
1723 add_setshow_zuinteger_cmd ("libthread-db", class_maintenance
,
1724 &libthread_db_debug
, _("\
1725 Set libthread-db debugging."), _("\
1726 Show libthread-db debugging."), _("\
1727 When non-zero, libthread-db debugging is enabled."),
1729 show_libthread_db_debug
,
1730 &setdebuglist
, &showdebuglist
);
1732 add_setshow_boolean_cmd ("libthread-db", class_support
,
1733 &auto_load_thread_db
, _("\
1734 Enable or disable auto-loading of inferior specific libthread_db."), _("\
1735 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
1736 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
1737 locations to load libthread_db compatible with the inferior.\n\
1738 Standard system libthread_db still gets loaded even with this option off.\n\
1739 This options has security implications for untrusted inferiors."),
1740 NULL
, show_auto_load_thread_db
,
1741 auto_load_set_cmdlist_get (),
1742 auto_load_show_cmdlist_get ());
1744 add_cmd ("libthread-db", class_info
, info_auto_load_libthread_db
,
1745 _("Print the list of loaded inferior specific libthread_db.\n\
1746 Usage: info auto-load libthread-db"),
1747 auto_load_info_cmdlist_get ());
1749 /* Add ourselves to objfile event chain. */
1750 observer_attach_new_objfile (thread_db_new_objfile
);
1752 /* Add ourselves to inferior_created event chain.
1753 This is needed to handle debugging statically linked programs where
1754 the new_objfile observer won't get called for libpthread. */
1755 observer_attach_inferior_created (thread_db_inferior_created
);