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 switch (ourstatus
->kind
)
1121 case TARGET_WAITKIND_IGNORE
:
1122 case TARGET_WAITKIND_EXITED
:
1123 case TARGET_WAITKIND_THREAD_EXITED
:
1124 case TARGET_WAITKIND_SIGNALLED
:
1128 info
= get_thread_db_info (ptid_get_pid (ptid
));
1130 /* If this process isn't using thread_db, we're done. */
1134 if (ourstatus
->kind
== TARGET_WAITKIND_EXECD
)
1136 /* New image, it may or may not end up using thread_db. Assume
1137 not unless we find otherwise. */
1138 delete_thread_db_info (ptid_get_pid (ptid
));
1139 if (!thread_db_list
)
1140 unpush_target (&thread_db_ops
);
1145 /* Fill in the thread's user-level thread id and status. */
1146 thread_from_lwp (ptid
);
1152 thread_db_mourn_inferior (struct target_ops
*ops
)
1154 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1156 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1158 target_beneath
->to_mourn_inferior (target_beneath
);
1160 /* Detach thread_db target ops. */
1161 if (!thread_db_list
)
1162 unpush_target (ops
);
1165 struct callback_data
1167 struct thread_db_info
*info
;
1172 find_new_threads_callback (const td_thrhandle_t
*th_p
, void *data
)
1177 struct thread_info
*tp
;
1178 struct callback_data
*cb_data
= (struct callback_data
*) data
;
1179 struct thread_db_info
*info
= cb_data
->info
;
1181 err
= info
->td_thr_get_info_p (th_p
, &ti
);
1183 error (_("find_new_threads_callback: cannot get thread info: %s"),
1184 thread_db_err_str (err
));
1186 if (ti
.ti_lid
== -1)
1188 /* A thread with kernel thread ID -1 is either a thread that
1189 exited and was joined, or a thread that is being created but
1190 hasn't started yet, and that is reusing the tcb/stack of a
1191 thread that previously exited and was joined. (glibc marks
1192 terminated and joined threads with kernel thread ID -1. See
1194 if (libthread_db_debug
)
1195 fprintf_unfiltered (gdb_stdlog
,
1196 "thread_db: skipping exited and "
1197 "joined thread (0x%lx)\n",
1198 (unsigned long) ti
.ti_tid
);
1204 /* A thread ID of zero means that this is the main thread, but
1205 glibc has not yet initialized thread-local storage and the
1206 pthread library. We do not know what the thread's TID will
1209 /* In that case, we're not stopped in a fork syscall and don't
1210 need this glibc bug workaround. */
1211 info
->need_stale_parent_threads_check
= 0;
1216 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1217 bit expensive, as it needs to open /proc/pid/status, so try to
1218 avoid doing the work if we know we don't have to. */
1219 if (info
->need_stale_parent_threads_check
)
1221 int tgid
= linux_proc_get_tgid (ti
.ti_lid
);
1223 if (tgid
!= -1 && tgid
!= info
->pid
)
1227 ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
1228 tp
= find_thread_ptid (ptid
);
1229 if (tp
== NULL
|| tp
->priv
== NULL
)
1230 record_thread (info
, tp
, ptid
, th_p
, &ti
);
1235 /* Helper for thread_db_find_new_threads_2.
1236 Returns number of new threads found. */
1239 find_new_threads_once (struct thread_db_info
*info
, int iteration
,
1242 struct callback_data data
;
1243 td_err_e err
= TD_ERR
;
1246 data
.new_threads
= 0;
1248 /* See comment in thread_db_update_thread_list. */
1249 gdb_assert (info
->td_ta_thr_iter_p
!= NULL
);
1253 /* Iterate over all user-space threads to discover new threads. */
1254 err
= info
->td_ta_thr_iter_p (info
->thread_agent
,
1255 find_new_threads_callback
,
1258 TD_THR_LOWEST_PRIORITY
,
1260 TD_THR_ANY_USER_FLAGS
);
1262 CATCH (except
, RETURN_MASK_ERROR
)
1264 if (libthread_db_debug
)
1266 exception_fprintf (gdb_stdlog
, except
,
1267 "Warning: find_new_threads_once: ");
1272 if (libthread_db_debug
)
1274 fprintf_unfiltered (gdb_stdlog
,
1275 _("Found %d new threads in iteration %d.\n"),
1276 data
.new_threads
, iteration
);
1282 return data
.new_threads
;
1285 /* Search for new threads, accessing memory through stopped thread
1286 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1287 searches in a row do not discover any new threads. */
1290 thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
)
1292 td_err_e err
= TD_OK
;
1293 struct thread_db_info
*info
;
1296 info
= get_thread_db_info (ptid_get_pid (ptid
));
1298 /* Access an lwp we know is stopped. */
1299 info
->proc_handle
.ptid
= ptid
;
1303 /* Require 4 successive iterations which do not find any new threads.
1304 The 4 is a heuristic: there is an inherent race here, and I have
1305 seen that 2 iterations in a row are not always sufficient to
1306 "capture" all threads. */
1307 for (i
= 0, loop
= 0; loop
< 4 && err
== TD_OK
; ++i
, ++loop
)
1308 if (find_new_threads_once (info
, i
, &err
) != 0)
1310 /* Found some new threads. Restart the loop from beginning. */
1315 find_new_threads_once (info
, 0, &err
);
1318 error (_("Cannot find new threads: %s"), thread_db_err_str (err
));
1322 thread_db_find_new_threads_1 (ptid_t ptid
)
1324 thread_db_find_new_threads_2 (ptid
, 0);
1327 /* Implement the to_update_thread_list target method for this
1331 thread_db_update_thread_list (struct target_ops
*ops
)
1333 struct thread_db_info
*info
;
1334 struct inferior
*inf
;
1340 struct thread_info
*thread
;
1345 info
= get_thread_db_info (inf
->pid
);
1349 thread
= any_live_thread_of_process (inf
->pid
);
1350 if (thread
== NULL
|| thread
->executing
)
1353 /* It's best to avoid td_ta_thr_iter if possible. That walks
1354 data structures in the inferior's address space that may be
1355 corrupted, or, if the target is running, the list may change
1356 while we walk it. In the latter case, it's possible that a
1357 thread exits just at the exact time that causes GDB to get
1358 stuck in an infinite loop. To avoid pausing all threads
1359 whenever the core wants to refresh the thread list, we
1360 instead use thread_from_lwp immediately when we see an LWP
1361 stop. That uses thread_db entry points that do not walk
1362 libpthread's thread list, so should be safe, as well as more
1364 if (target_has_execution_1 (thread
->ptid
))
1367 thread_db_find_new_threads_1 (thread
->ptid
);
1370 /* Give the beneath target a chance to do extra processing. */
1371 ops
->beneath
->to_update_thread_list (ops
->beneath
);
1375 thread_db_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
1377 struct thread_info
*thread_info
= find_thread_ptid (ptid
);
1378 struct target_ops
*beneath
;
1380 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1382 static char buf
[64];
1385 tid
= thread_info
->priv
->tid
;
1386 snprintf (buf
, sizeof (buf
), "Thread 0x%lx (LWP %ld)",
1387 (unsigned long) tid
, ptid_get_lwp (ptid
));
1392 beneath
= find_target_beneath (ops
);
1393 return beneath
->to_pid_to_str (beneath
, ptid
);
1396 /* Return a string describing the state of the thread specified by
1400 thread_db_extra_thread_info (struct target_ops
*self
,
1401 struct thread_info
*info
)
1403 if (info
->priv
== NULL
)
1406 if (info
->priv
->dying
)
1412 /* Get the address of the thread local variable in load module LM which
1413 is stored at OFFSET within the thread local storage for thread PTID. */
1416 thread_db_get_thread_local_address (struct target_ops
*ops
,
1421 struct thread_info
*thread_info
;
1422 struct target_ops
*beneath
;
1424 /* Find the matching thread. */
1425 thread_info
= find_thread_ptid (ptid
);
1427 /* We may not have discovered the thread yet. */
1428 if (thread_info
!= NULL
&& thread_info
->priv
== NULL
)
1429 thread_info
= thread_from_lwp (ptid
);
1431 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1435 struct thread_db_info
*info
;
1437 info
= get_thread_db_info (ptid_get_pid (ptid
));
1439 /* Finally, get the address of the variable. */
1442 /* glibc doesn't provide the needed interface. */
1443 if (!info
->td_thr_tls_get_addr_p
)
1444 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR
,
1445 _("No TLS library support"));
1447 /* Note the cast through uintptr_t: this interface only works if
1448 a target address fits in a psaddr_t, which is a host pointer.
1449 So a 32-bit debugger can not access 64-bit TLS through this. */
1450 err
= info
->td_thr_tls_get_addr_p (&thread_info
->priv
->th
,
1451 (psaddr_t
)(uintptr_t) lm
,
1456 /* If glibc doesn't provide the needed interface throw an error
1457 that LM is zero - normally cases it should not be. */
1458 if (!info
->td_thr_tlsbase_p
)
1459 throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR
,
1460 _("TLS load module not found"));
1462 /* This code path handles the case of -static -pthread executables:
1463 https://sourceware.org/ml/libc-help/2014-03/msg00024.html
1464 For older GNU libc r_debug.r_map is NULL. For GNU libc after
1465 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
1466 The constant number 1 depends on GNU __libc_setup_tls
1467 initialization of l_tls_modid to 1. */
1468 err
= info
->td_thr_tlsbase_p (&thread_info
->priv
->th
,
1470 address
= (char *) address
+ offset
;
1473 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1474 /* The memory hasn't been allocated, yet. */
1475 if (err
== TD_NOTALLOC
)
1476 /* Now, if libthread_db provided the initialization image's
1477 address, we *could* try to build a non-lvalue value from
1478 the initialization image. */
1479 throw_error (TLS_NOT_ALLOCATED_YET_ERROR
,
1480 _("TLS not allocated yet"));
1483 /* Something else went wrong. */
1485 throw_error (TLS_GENERIC_ERROR
,
1486 (("%s")), thread_db_err_str (err
));
1488 /* Cast assuming host == target. Joy. */
1489 /* Do proper sign extension for the target. */
1490 gdb_assert (exec_bfd
);
1491 return (bfd_get_sign_extend_vma (exec_bfd
) > 0
1492 ? (CORE_ADDR
) (intptr_t) address
1493 : (CORE_ADDR
) (uintptr_t) address
);
1496 beneath
= find_target_beneath (ops
);
1497 return beneath
->to_get_thread_local_address (beneath
, ptid
, lm
, offset
);
1500 /* Implement the to_get_ada_task_ptid target method for this target. */
1503 thread_db_get_ada_task_ptid (struct target_ops
*self
, long lwp
, long thread
)
1505 /* NPTL uses a 1:1 model, so the LWP id suffices. */
1506 return ptid_build (ptid_get_pid (inferior_ptid
), lwp
, 0);
1510 thread_db_resume (struct target_ops
*ops
,
1511 ptid_t ptid
, int step
, enum gdb_signal signo
)
1513 struct target_ops
*beneath
= find_target_beneath (ops
);
1514 struct thread_db_info
*info
;
1516 if (ptid_equal (ptid
, minus_one_ptid
))
1517 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1519 info
= get_thread_db_info (ptid_get_pid (ptid
));
1521 /* This workaround is only needed for child fork lwps stopped in a
1522 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1523 workaround can be disabled. */
1525 info
->need_stale_parent_threads_check
= 0;
1527 beneath
->to_resume (beneath
, ptid
, step
, signo
);
1530 /* qsort helper function for info_auto_load_libthread_db, sort the
1531 thread_db_info pointers primarily by their FILENAME and secondarily by their
1532 PID, both in ascending order. */
1535 info_auto_load_libthread_db_compare (const void *ap
, const void *bp
)
1537 struct thread_db_info
*a
= *(struct thread_db_info
**) ap
;
1538 struct thread_db_info
*b
= *(struct thread_db_info
**) bp
;
1541 retval
= strcmp (a
->filename
, b
->filename
);
1545 return (a
->pid
> b
->pid
) - (a
->pid
- b
->pid
);
1548 /* Implement 'info auto-load libthread-db'. */
1551 info_auto_load_libthread_db (char *args
, int from_tty
)
1553 struct ui_out
*uiout
= current_uiout
;
1554 const char *cs
= args
? args
: "";
1555 struct thread_db_info
*info
, **array
;
1556 unsigned info_count
, unique_filenames
;
1557 size_t max_filename_len
, max_pids_len
, pids_len
;
1558 struct cleanup
*back_to
;
1562 cs
= skip_spaces_const (cs
);
1564 error (_("'info auto-load libthread-db' does not accept any parameters"));
1567 for (info
= thread_db_list
; info
; info
= info
->next
)
1568 if (info
->filename
!= NULL
)
1571 array
= XNEWVEC (struct thread_db_info
*, info_count
);
1572 back_to
= make_cleanup (xfree
, array
);
1575 for (info
= thread_db_list
; info
; info
= info
->next
)
1576 if (info
->filename
!= NULL
)
1577 array
[info_count
++] = info
;
1579 /* Sort ARRAY by filenames and PIDs. */
1581 qsort (array
, info_count
, sizeof (*array
),
1582 info_auto_load_libthread_db_compare
);
1584 /* Calculate the number of unique filenames (rows) and the maximum string
1585 length of PIDs list for the unique filenames (columns). */
1587 unique_filenames
= 0;
1588 max_filename_len
= 0;
1591 for (i
= 0; i
< info_count
; i
++)
1593 int pid
= array
[i
]->pid
;
1594 size_t this_pid_len
;
1596 for (this_pid_len
= 0; pid
!= 0; pid
/= 10)
1599 if (i
== 0 || strcmp (array
[i
- 1]->filename
, array
[i
]->filename
) != 0)
1602 max_filename_len
= max (max_filename_len
,
1603 strlen (array
[i
]->filename
));
1607 pids_len
-= strlen (", ");
1608 max_pids_len
= max (max_pids_len
, pids_len
);
1612 pids_len
+= this_pid_len
+ strlen (", ");
1616 pids_len
-= strlen (", ");
1617 max_pids_len
= max (max_pids_len
, pids_len
);
1620 /* Table header shifted right by preceding "libthread-db: " would not match
1622 if (info_count
> 0 && args
== auto_load_info_scripts_pattern_nl
)
1623 ui_out_text (uiout
, "\n");
1625 make_cleanup_ui_out_table_begin_end (uiout
, 2, unique_filenames
,
1626 "LinuxThreadDbTable");
1628 ui_out_table_header (uiout
, max_filename_len
, ui_left
, "filename",
1630 ui_out_table_header (uiout
, pids_len
, ui_left
, "PIDs", "Pids");
1631 ui_out_table_body (uiout
);
1633 pids
= (char *) xmalloc (max_pids_len
+ 1);
1634 make_cleanup (xfree
, pids
);
1636 /* Note I is incremented inside the cycle, not at its end. */
1637 for (i
= 0; i
< info_count
;)
1639 struct cleanup
*chain
= make_cleanup_ui_out_tuple_begin_end (uiout
, NULL
);
1643 ui_out_field_string (uiout
, "filename", info
->filename
);
1646 while (i
< info_count
&& strcmp (info
->filename
, array
[i
]->filename
) == 0)
1648 if (pids_end
!= pids
)
1653 pids_end
+= xsnprintf (pids_end
, &pids
[max_pids_len
+ 1] - pids_end
,
1654 "%u", array
[i
]->pid
);
1655 gdb_assert (pids_end
< &pids
[max_pids_len
+ 1]);
1661 ui_out_field_string (uiout
, "pids", pids
);
1663 ui_out_text (uiout
, "\n");
1664 do_cleanups (chain
);
1667 do_cleanups (back_to
);
1669 if (info_count
== 0)
1670 ui_out_message (uiout
, 0, _("No auto-loaded libthread-db.\n"));
1674 init_thread_db_ops (void)
1676 thread_db_ops
.to_shortname
= "multi-thread";
1677 thread_db_ops
.to_longname
= "multi-threaded child process.";
1678 thread_db_ops
.to_doc
= "Threads and pthreads support.";
1679 thread_db_ops
.to_detach
= thread_db_detach
;
1680 thread_db_ops
.to_wait
= thread_db_wait
;
1681 thread_db_ops
.to_resume
= thread_db_resume
;
1682 thread_db_ops
.to_mourn_inferior
= thread_db_mourn_inferior
;
1683 thread_db_ops
.to_update_thread_list
= thread_db_update_thread_list
;
1684 thread_db_ops
.to_pid_to_str
= thread_db_pid_to_str
;
1685 thread_db_ops
.to_stratum
= thread_stratum
;
1686 thread_db_ops
.to_has_thread_control
= tc_schedlock
;
1687 thread_db_ops
.to_get_thread_local_address
1688 = thread_db_get_thread_local_address
;
1689 thread_db_ops
.to_extra_thread_info
= thread_db_extra_thread_info
;
1690 thread_db_ops
.to_get_ada_task_ptid
= thread_db_get_ada_task_ptid
;
1691 thread_db_ops
.to_magic
= OPS_MAGIC
;
1693 complete_target_initialization (&thread_db_ops
);
1696 /* Provide a prototype to silence -Wmissing-prototypes. */
1697 extern initialize_file_ftype _initialize_thread_db
;
1700 _initialize_thread_db (void)
1702 init_thread_db_ops ();
1704 /* Defer loading of libthread_db.so until inferior is running.
1705 This allows gdb to load correct libthread_db for a given
1706 executable -- there could be multiple versions of glibc,
1707 and until there is a running inferior, we can't tell which
1708 libthread_db is the correct one to load. */
1710 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
1712 add_setshow_optional_filename_cmd ("libthread-db-search-path",
1714 &libthread_db_search_path
, _("\
1715 Set search path for libthread_db."), _("\
1716 Show the current search path or libthread_db."), _("\
1717 This path is used to search for libthread_db to be loaded into \
1719 Its value is a colon (':') separate list of directories to search.\n\
1720 Setting the search path to an empty list resets it to its default value."),
1721 set_libthread_db_search_path
,
1723 &setlist
, &showlist
);
1725 add_setshow_zuinteger_cmd ("libthread-db", class_maintenance
,
1726 &libthread_db_debug
, _("\
1727 Set libthread-db debugging."), _("\
1728 Show libthread-db debugging."), _("\
1729 When non-zero, libthread-db debugging is enabled."),
1731 show_libthread_db_debug
,
1732 &setdebuglist
, &showdebuglist
);
1734 add_setshow_boolean_cmd ("libthread-db", class_support
,
1735 &auto_load_thread_db
, _("\
1736 Enable or disable auto-loading of inferior specific libthread_db."), _("\
1737 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
1738 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
1739 locations to load libthread_db compatible with the inferior.\n\
1740 Standard system libthread_db still gets loaded even with this option off.\n\
1741 This options has security implications for untrusted inferiors."),
1742 NULL
, show_auto_load_thread_db
,
1743 auto_load_set_cmdlist_get (),
1744 auto_load_show_cmdlist_get ());
1746 add_cmd ("libthread-db", class_info
, info_auto_load_libthread_db
,
1747 _("Print the list of loaded inferior specific libthread_db.\n\
1748 Usage: info auto-load libthread-db"),
1749 auto_load_info_cmdlist_get ());
1751 /* Add ourselves to objfile event chain. */
1752 observer_attach_new_objfile (thread_db_new_objfile
);
1754 /* Add ourselves to inferior_created event chain.
1755 This is needed to handle debugging statically linked programs where
1756 the new_objfile observer won't get called for libpthread. */
1757 observer_attach_inferior_created (thread_db_inferior_created
);