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 struct thread_info
*record_thread
202 (struct thread_db_info
*info
, struct thread_info
*tp
,
203 ptid_t ptid
, const td_thrhandle_t
*th_p
, const td_thrinfo_t
*ti_p
);
205 /* Add the current inferior to the list of processes using libpthread.
206 Return a pointer to the newly allocated object that was added to
207 THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
210 static struct thread_db_info
*
211 add_thread_db_info (void *handle
)
213 struct thread_db_info
*info
= XCNEW (struct thread_db_info
);
215 info
->pid
= ptid_get_pid (inferior_ptid
);
216 info
->handle
= handle
;
218 /* The workaround works by reading from /proc/pid/status, so it is
219 disabled for core files. */
220 if (target_has_execution
)
221 info
->need_stale_parent_threads_check
= 1;
223 info
->next
= thread_db_list
;
224 thread_db_list
= info
;
229 /* Return the thread_db_info object representing the bookkeeping
230 related to process PID, if any; NULL otherwise. */
232 static struct thread_db_info
*
233 get_thread_db_info (int pid
)
235 struct thread_db_info
*info
;
237 for (info
= thread_db_list
; info
; info
= info
->next
)
238 if (pid
== info
->pid
)
244 /* When PID has exited or has been detached, we no longer want to keep
245 track of it as using libpthread. Call this function to discard
246 thread_db related info related to PID. Note that this closes
247 LIBTHREAD_DB_SO's dlopen'ed handle. */
250 delete_thread_db_info (int pid
)
252 struct thread_db_info
*info
, *info_prev
;
256 for (info
= thread_db_list
; info
; info_prev
= info
, info
= info
->next
)
257 if (pid
== info
->pid
)
263 if (info
->handle
!= NULL
)
264 dlclose (info
->handle
);
266 xfree (info
->filename
);
269 info_prev
->next
= info
->next
;
271 thread_db_list
= info
->next
;
276 /* Prototypes for local functions. */
277 static int attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
278 const td_thrinfo_t
*ti_p
);
279 static void detach_thread (ptid_t ptid
);
282 /* Use "struct private_thread_info" to cache thread state. This is
283 a substantial optimization. */
285 struct private_thread_info
287 /* Flag set when we see a TD_DEATH event for this thread. */
288 unsigned int dying
:1;
290 /* Cached thread state. */
297 thread_db_err_str (td_err_e err
)
304 return "generic 'call succeeded'";
306 return "generic error";
308 return "no thread to satisfy query";
310 return "no sync handle to satisfy query";
312 return "no LWP to satisfy query";
314 return "invalid process handle";
316 return "invalid thread handle";
318 return "invalid synchronization handle";
320 return "invalid thread agent";
322 return "invalid key";
324 return "no event message for getmsg";
326 return "FPU register set not available";
328 return "application not linked with libthread";
330 return "requested event is not supported";
332 return "capability not available";
334 return "debugger service failed";
336 return "operation not applicable to";
338 return "no thread-specific data for this thread";
340 return "malloc failed";
342 return "only part of register set was written/read";
344 return "X register set not available for this thread";
345 #ifdef THREAD_DB_HAS_TD_NOTALLOC
347 return "thread has not yet allocated TLS for given module";
349 #ifdef THREAD_DB_HAS_TD_VERSION
351 return "versions of libpthread and libthread_db do not match";
353 #ifdef THREAD_DB_HAS_TD_NOTLS
355 return "there is no TLS segment in the given module";
358 snprintf (buf
, sizeof (buf
), "unknown thread_db error '%d'", err
);
363 /* Return 1 if any threads have been registered. There may be none if
364 the threading library is not fully initialized yet. */
367 have_threads_callback (struct thread_info
*thread
, void *args
)
369 int pid
= * (int *) args
;
371 if (ptid_get_pid (thread
->ptid
) != pid
)
374 return thread
->priv
!= NULL
;
378 have_threads (ptid_t ptid
)
380 int pid
= ptid_get_pid (ptid
);
382 return iterate_over_threads (have_threads_callback
, &pid
) != NULL
;
386 /* Fetch the user-level thread id of PTID. */
388 static struct thread_info
*
389 thread_from_lwp (ptid_t ptid
)
394 struct thread_db_info
*info
;
395 struct thread_info
*tp
;
397 /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
400 /* This ptid comes from linux-nat.c, which should always fill in the
402 gdb_assert (ptid_get_lwp (ptid
) != 0);
404 info
= get_thread_db_info (ptid_get_pid (ptid
));
406 /* Access an lwp we know is stopped. */
407 info
->proc_handle
.ptid
= ptid
;
408 err
= info
->td_ta_map_lwp2thr_p (info
->thread_agent
, ptid_get_lwp (ptid
),
411 error (_("Cannot find user-level thread for LWP %ld: %s"),
412 ptid_get_lwp (ptid
), thread_db_err_str (err
));
414 err
= info
->td_thr_get_info_p (&th
, &ti
);
416 error (_("thread_get_info_callback: cannot get thread info: %s"),
417 thread_db_err_str (err
));
419 /* Fill the cache. */
420 tp
= find_thread_ptid (ptid
);
421 return record_thread (info
, tp
, ptid
, &th
, &ti
);
425 /* See linux-nat.h. */
428 thread_db_notice_clone (ptid_t parent
, ptid_t child
)
433 struct thread_db_info
*info
;
435 info
= get_thread_db_info (ptid_get_pid (child
));
440 thread_from_lwp (child
);
442 /* If we do not know about the main thread yet, this would be a good
444 thread_from_lwp (parent
);
449 verbose_dlsym (void *handle
, const char *name
)
451 void *sym
= dlsym (handle
, name
);
453 warning (_("Symbol \"%s\" not found in libthread_db: %s"),
459 enable_thread_event (td_event_e event
, CORE_ADDR
*bp
)
463 struct thread_db_info
*info
;
465 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
467 /* Access an lwp we know is stopped. */
468 info
->proc_handle
.ptid
= inferior_ptid
;
470 /* Get the breakpoint address for thread EVENT. */
471 err
= info
->td_ta_event_addr_p (info
->thread_agent
, event
, ¬ify
);
475 /* Set up the breakpoint. */
476 gdb_assert (exec_bfd
);
477 (*bp
) = (gdbarch_convert_from_func_ptr_addr
479 /* Do proper sign extension for the target. */
480 (bfd_get_sign_extend_vma (exec_bfd
) > 0
481 ? (CORE_ADDR
) (intptr_t) notify
.u
.bptaddr
482 : (CORE_ADDR
) (uintptr_t) notify
.u
.bptaddr
),
484 create_thread_event_breakpoint (target_gdbarch (), *bp
);
489 /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
490 return 1 if this version is lower (and not equal) to
491 VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
494 inferior_has_bug (const char *ver_symbol
, int ver_major_min
, int ver_minor_min
)
496 struct bound_minimal_symbol version_msym
;
497 CORE_ADDR version_addr
;
499 int err
, got
, retval
= 0;
501 version_msym
= lookup_minimal_symbol (ver_symbol
, NULL
, NULL
);
502 if (version_msym
.minsym
== NULL
)
505 version_addr
= BMSYMBOL_VALUE_ADDRESS (version_msym
);
506 got
= target_read_string (version_addr
, &version
, 32, &err
);
507 if (err
== 0 && memchr (version
, 0, got
) == &version
[got
-1])
511 retval
= (sscanf (version
, "%d.%d", &major
, &minor
) == 2
512 && (major
< ver_major_min
513 || (major
== ver_major_min
&& minor
< ver_minor_min
)));
521 enable_thread_event_reporting (void)
523 td_thr_events_t events
;
525 struct thread_db_info
*info
;
527 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
529 /* We cannot use the thread event reporting facility if these
530 functions aren't available. */
531 if (info
->td_ta_event_addr_p
== NULL
532 || info
->td_ta_set_event_p
== NULL
533 || info
->td_ta_event_getmsg_p
== NULL
534 || info
->td_thr_event_enable_p
== NULL
)
537 /* Set the process wide mask saying which events we're interested in. */
538 td_event_emptyset (&events
);
539 td_event_addset (&events
, TD_CREATE
);
541 /* There is a bug fixed between linuxthreads 2.1.3 and 2.2 by
542 commit 2e4581e4fba917f1779cd0a010a45698586c190a
543 * manager.c (pthread_exited): Correctly report event as TD_REAP
544 instead of TD_DEATH. Fix comments.
545 where event reporting facility is broken for TD_DEATH events,
546 so don't enable it if we have glibc but a lower version. */
547 if (!inferior_has_bug ("__linuxthreads_version", 2, 2))
548 td_event_addset (&events
, TD_DEATH
);
550 err
= info
->td_ta_set_event_p (info
->thread_agent
, &events
);
553 warning (_("Unable to set global thread event mask: %s"),
554 thread_db_err_str (err
));
558 /* Delete previous thread event breakpoints, if any. */
559 remove_thread_event_breakpoints ();
560 info
->td_create_bp_addr
= 0;
561 info
->td_death_bp_addr
= 0;
563 /* Set up the thread creation event. */
564 err
= enable_thread_event (TD_CREATE
, &info
->td_create_bp_addr
);
567 warning (_("Unable to get location for thread creation breakpoint: %s"),
568 thread_db_err_str (err
));
572 /* Set up the thread death event. */
573 err
= enable_thread_event (TD_DEATH
, &info
->td_death_bp_addr
);
576 warning (_("Unable to get location for thread death breakpoint: %s"),
577 thread_db_err_str (err
));
582 /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
585 Return 1 if the caller should abort libthread_db initialization. Return 0
589 thread_db_find_new_threads_silently (ptid_t ptid
)
594 thread_db_find_new_threads_2 (ptid
, 1);
597 CATCH (except
, RETURN_MASK_ERROR
)
599 if (libthread_db_debug
)
600 exception_fprintf (gdb_stdlog
, except
,
601 "Warning: thread_db_find_new_threads_silently: ");
603 /* There is a bug fixed between nptl 2.6.1 and 2.7 by
604 commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
605 where calls to td_thr_get_info fail with TD_ERR for statically linked
606 executables if td_thr_get_info is called before glibc has initialized
609 If the nptl bug is NOT present in the inferior and still thread_db
610 reports an error return 1. It means the inferior has corrupted thread
611 list and GDB should fall back only to LWPs.
613 If the nptl bug is present in the inferior return 0 to silently ignore
614 such errors, and let gdb enumerate threads again later. In such case
615 GDB cannot properly display LWPs if the inferior thread list is
616 corrupted. For core files it does not apply, no 'later enumeration'
619 if (!target_has_execution
|| !inferior_has_bug ("nptl_version", 2, 7))
621 exception_fprintf (gdb_stderr
, except
,
622 _("Warning: couldn't activate thread debugging "
623 "using libthread_db: "));
632 /* Lookup a library in which given symbol resides.
633 Note: this is looking in GDB process, not in the inferior.
634 Returns library name, or NULL. */
637 dladdr_to_soname (const void *addr
)
641 if (dladdr (addr
, &info
) != 0)
642 return info
.dli_fname
;
646 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
648 Failure could happen if libthread_db does not have symbols we expect,
649 or when it refuses to work with the current inferior (e.g. due to
650 version mismatch between libthread_db and libpthread). */
653 try_thread_db_load_1 (struct thread_db_info
*info
)
657 /* Initialize pointers to the dynamic library functions we will use.
658 Essential functions first. */
660 #define TDB_VERBOSE_DLSYM(info, func) \
661 info->func ## _p = (func ## _ftype *) verbose_dlsym (info->handle, #func)
663 #define TDB_DLSYM(info, func) \
664 info->func ## _p = (func ## _ftype *) dlsym (info->handle, #func)
673 CHK (TDB_VERBOSE_DLSYM (info
, td_init
));
675 err
= info
->td_init_p ();
678 warning (_("Cannot initialize libthread_db: %s"),
679 thread_db_err_str (err
));
683 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_new
));
685 /* Initialize the structure that identifies the child process. */
686 info
->proc_handle
.ptid
= inferior_ptid
;
688 /* Now attempt to open a connection to the thread library. */
689 err
= info
->td_ta_new_p (&info
->proc_handle
, &info
->thread_agent
);
692 if (libthread_db_debug
)
693 fprintf_unfiltered (gdb_stdlog
, _("td_ta_new failed: %s\n"),
694 thread_db_err_str (err
));
699 #ifdef THREAD_DB_HAS_TD_VERSION
702 /* The errors above are not unexpected and silently ignored:
703 they just mean we haven't found correct version of
707 warning (_("td_ta_new failed: %s"), thread_db_err_str (err
));
712 /* These are essential. */
713 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_map_lwp2thr
));
714 CHK (TDB_VERBOSE_DLSYM (info
, td_ta_thr_iter
));
715 CHK (TDB_VERBOSE_DLSYM (info
, td_thr_validate
));
716 CHK (TDB_VERBOSE_DLSYM (info
, td_thr_get_info
));
718 /* These are not essential. */
719 TDB_DLSYM (info
, td_ta_event_addr
);
720 TDB_DLSYM (info
, td_ta_set_event
);
721 TDB_DLSYM (info
, td_ta_clear_event
);
722 TDB_DLSYM (info
, td_ta_event_getmsg
);
723 TDB_DLSYM (info
, td_thr_event_enable
);
724 TDB_DLSYM (info
, td_thr_tls_get_addr
);
725 TDB_DLSYM (info
, td_thr_tlsbase
);
727 #undef TDB_VERBOSE_DLSYM
731 /* It's best to avoid td_ta_thr_iter if possible. That walks data
732 structures in the inferior's address space that may be corrupted,
733 or, if the target is running, may change while we walk them. If
734 there's execution (and /proc is mounted), then we're already
735 attached to all LWPs. Use thread_from_lwp, which uses
736 td_ta_map_lwp2thr instead, which does not walk the thread list.
738 td_ta_map_lwp2thr uses ps_get_thread_area, but we can't use that
739 currently on core targets, as it uses ptrace directly. */
740 if (target_has_execution
741 && linux_proc_task_list_dir_exists (ptid_get_pid (inferior_ptid
)))
744 int pid
= ptid_get_pid (inferior_ptid
);
746 linux_stop_and_wait_all_lwps ();
749 if (ptid_get_pid (lp
->ptid
) == pid
)
750 thread_from_lwp (lp
->ptid
);
752 linux_unstop_all_lwps ();
754 else if (thread_db_find_new_threads_silently (inferior_ptid
) != 0)
756 /* Even if libthread_db initializes, if the thread list is
757 corrupted, we'd not manage to list any threads. Better reject this
758 thread_db, and fall back to at least listing LWPs. */
762 printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
764 if (*libthread_db_search_path
|| libthread_db_debug
)
766 struct ui_file
*file
;
769 library
= dladdr_to_soname (*info
->td_ta_new_p
);
771 library
= LIBTHREAD_DB_SO
;
773 /* If we'd print this to gdb_stdout when debug output is
774 disabled, still print it to gdb_stdout if debug output is
775 enabled. User visible output should not depend on debug
777 file
= *libthread_db_search_path
!= '\0' ? gdb_stdout
: gdb_stdlog
;
778 fprintf_unfiltered (file
, _("Using host libthread_db library \"%s\".\n"),
782 /* The thread library was detected. Activate the thread_db target
783 if this is the first process using it. */
784 if (thread_db_list
->next
== NULL
)
785 push_target (&thread_db_ops
);
787 /* Enable event reporting, but not when debugging a core file. */
788 if (target_has_execution
&& thread_db_use_events ())
789 enable_thread_event_reporting ();
794 /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
795 relative, or just LIBTHREAD_DB. */
798 try_thread_db_load (const char *library
, int check_auto_load_safe
)
801 struct thread_db_info
*info
;
803 if (libthread_db_debug
)
804 fprintf_unfiltered (gdb_stdlog
,
805 _("Trying host libthread_db library: %s.\n"),
808 if (check_auto_load_safe
)
810 if (access (library
, R_OK
) != 0)
812 /* Do not print warnings by file_is_auto_load_safe if the library does
813 not exist at this place. */
814 if (libthread_db_debug
)
815 fprintf_unfiltered (gdb_stdlog
, _("open failed: %s.\n"),
816 safe_strerror (errno
));
820 if (!file_is_auto_load_safe (library
, _("auto-load: Loading libthread-db "
821 "library \"%s\" from explicit "
827 handle
= dlopen (library
, RTLD_NOW
);
830 if (libthread_db_debug
)
831 fprintf_unfiltered (gdb_stdlog
, _("dlopen failed: %s.\n"), dlerror ());
835 if (libthread_db_debug
&& strchr (library
, '/') == NULL
)
839 td_init
= dlsym (handle
, "td_init");
842 const char *const libpath
= dladdr_to_soname (td_init
);
845 fprintf_unfiltered (gdb_stdlog
, _("Host %s resolved to: %s.\n"),
850 info
= add_thread_db_info (handle
);
852 /* Do not save system library name, that one is always trusted. */
853 if (strchr (library
, '/') != NULL
)
854 info
->filename
= gdb_realpath (library
);
856 if (try_thread_db_load_1 (info
))
859 /* This library "refused" to work on current inferior. */
860 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
864 /* Subroutine of try_thread_db_load_from_pdir to simplify it.
865 Try loading libthread_db in directory(OBJ)/SUBDIR.
866 SUBDIR may be NULL. It may also be something like "../lib64".
867 The result is true for success. */
870 try_thread_db_load_from_pdir_1 (struct objfile
*obj
, const char *subdir
)
872 struct cleanup
*cleanup
;
875 const char *obj_name
= objfile_name (obj
);
877 if (obj_name
[0] != '/')
879 warning (_("Expected absolute pathname for libpthread in the"
880 " inferior, but got %s."), obj_name
);
884 path
= xmalloc (strlen (obj_name
) + (subdir
? strlen (subdir
) + 1 : 0)
885 + 1 + strlen (LIBTHREAD_DB_SO
) + 1);
886 cleanup
= make_cleanup (xfree
, path
);
888 strcpy (path
, obj_name
);
889 cp
= strrchr (path
, '/');
890 /* This should at minimum hit the first character. */
891 gdb_assert (cp
!= NULL
);
898 strcat (cp
, LIBTHREAD_DB_SO
);
900 result
= try_thread_db_load (path
, 1);
902 do_cleanups (cleanup
);
906 /* Handle $pdir in libthread-db-search-path.
907 Look for libthread_db in directory(libpthread)/SUBDIR.
908 SUBDIR may be NULL. It may also be something like "../lib64".
909 The result is true for success. */
912 try_thread_db_load_from_pdir (const char *subdir
)
916 if (!auto_load_thread_db
)
920 if (libpthread_name_p (objfile_name (obj
)))
922 if (try_thread_db_load_from_pdir_1 (obj
, subdir
))
925 /* We may have found the separate-debug-info version of
926 libpthread, and it may live in a directory without a matching
928 if (obj
->separate_debug_objfile_backlink
!= NULL
)
929 return try_thread_db_load_from_pdir_1 (obj
->separate_debug_objfile_backlink
,
938 /* Handle $sdir in libthread-db-search-path.
939 Look for libthread_db in the system dirs, or wherever a plain
940 dlopen(file_without_path) will look.
941 The result is true for success. */
944 try_thread_db_load_from_sdir (void)
946 return try_thread_db_load (LIBTHREAD_DB_SO
, 0);
949 /* Try to load libthread_db from directory DIR of length DIR_LEN.
950 The result is true for success. */
953 try_thread_db_load_from_dir (const char *dir
, size_t dir_len
)
955 struct cleanup
*cleanup
;
959 if (!auto_load_thread_db
)
962 path
= xmalloc (dir_len
+ 1 + strlen (LIBTHREAD_DB_SO
) + 1);
963 cleanup
= make_cleanup (xfree
, path
);
965 memcpy (path
, dir
, dir_len
);
967 strcpy (path
+ dir_len
+ 1, LIBTHREAD_DB_SO
);
969 result
= try_thread_db_load (path
, 1);
971 do_cleanups (cleanup
);
975 /* Search libthread_db_search_path for libthread_db which "agrees"
976 to work on current inferior.
977 The result is true for success. */
980 thread_db_load_search (void)
982 VEC (char_ptr
) *dir_vec
;
983 struct cleanup
*cleanups
;
987 dir_vec
= dirnames_to_char_ptr_vec (libthread_db_search_path
);
988 cleanups
= make_cleanup_free_char_ptr_vec (dir_vec
);
990 for (i
= 0; VEC_iterate (char_ptr
, dir_vec
, i
, this_dir
); ++i
)
992 const int pdir_len
= sizeof ("$pdir") - 1;
995 this_dir_len
= strlen (this_dir
);
997 if (strncmp (this_dir
, "$pdir", pdir_len
) == 0
998 && (this_dir
[pdir_len
] == '\0'
999 || this_dir
[pdir_len
] == '/'))
1001 char *subdir
= NULL
;
1002 struct cleanup
*free_subdir_cleanup
1003 = make_cleanup (null_cleanup
, NULL
);
1005 if (this_dir
[pdir_len
] == '/')
1007 subdir
= xmalloc (strlen (this_dir
));
1008 make_cleanup (xfree
, subdir
);
1009 strcpy (subdir
, this_dir
+ pdir_len
+ 1);
1011 rc
= try_thread_db_load_from_pdir (subdir
);
1012 do_cleanups (free_subdir_cleanup
);
1016 else if (strcmp (this_dir
, "$sdir") == 0)
1018 if (try_thread_db_load_from_sdir ())
1026 if (try_thread_db_load_from_dir (this_dir
, this_dir_len
))
1034 do_cleanups (cleanups
);
1035 if (libthread_db_debug
)
1036 fprintf_unfiltered (gdb_stdlog
,
1037 _("thread_db_load_search returning %d\n"), rc
);
1041 /* Return non-zero if the inferior has a libpthread. */
1044 has_libpthread (void)
1046 struct objfile
*obj
;
1049 if (libpthread_name_p (objfile_name (obj
)))
1055 /* Attempt to load and initialize libthread_db.
1056 Return 1 on success. */
1059 thread_db_load (void)
1061 struct thread_db_info
*info
;
1063 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1068 /* Don't attempt to use thread_db on executables not running
1070 if (!target_has_registers
)
1073 /* Don't attempt to use thread_db for remote targets. */
1074 if (!(target_can_run (¤t_target
) || core_bfd
))
1077 if (thread_db_load_search ())
1080 /* We couldn't find a libthread_db.
1081 If the inferior has a libpthread warn the user. */
1082 if (has_libpthread ())
1084 warning (_("Unable to find libthread_db matching inferior's thread"
1085 " library, thread debugging will not be available."));
1089 /* Either this executable isn't using libpthread at all, or it is
1090 statically linked. Since we can't easily distinguish these two cases,
1091 no warning is issued. */
1096 disable_thread_event_reporting (struct thread_db_info
*info
)
1098 if (info
->td_ta_clear_event_p
!= NULL
)
1100 td_thr_events_t events
;
1102 /* Set the process wide mask saying we aren't interested in any
1104 td_event_fillset (&events
);
1105 info
->td_ta_clear_event_p (info
->thread_agent
, &events
);
1108 info
->td_create_bp_addr
= 0;
1109 info
->td_death_bp_addr
= 0;
1113 check_thread_signals (void)
1115 if (!thread_signals
)
1120 lin_thread_get_thread_signals (&mask
);
1121 sigemptyset (&thread_stop_set
);
1122 sigemptyset (&thread_print_set
);
1124 for (i
= 1; i
< NSIG
; i
++)
1126 if (sigismember (&mask
, i
))
1128 if (signal_stop_update (gdb_signal_from_host (i
), 0))
1129 sigaddset (&thread_stop_set
, i
);
1130 if (signal_print_update (gdb_signal_from_host (i
), 0))
1131 sigaddset (&thread_print_set
, i
);
1138 /* Check whether thread_db is usable. This function is called when
1139 an inferior is created (or otherwise acquired, e.g. attached to)
1140 and when new shared libraries are loaded into a running process. */
1143 check_for_thread_db (void)
1145 /* Do nothing if we couldn't load libthread_db.so.1. */
1146 if (!thread_db_load ())
1150 /* This function is called via the new_objfile observer. */
1153 thread_db_new_objfile (struct objfile
*objfile
)
1155 /* This observer must always be called with inferior_ptid set
1159 /* libpthread with separate debug info has its debug info file already
1160 loaded (and notified without successful thread_db initialization)
1161 the time observer_notify_new_objfile is called for the library itself.
1162 Static executables have their separate debug info loaded already
1163 before the inferior has started. */
1164 && objfile
->separate_debug_objfile_backlink
== NULL
1165 /* Only check for thread_db if we loaded libpthread,
1166 or if this is the main symbol file.
1167 We need to check OBJF_MAINLINE to handle the case of debugging
1168 a statically linked executable AND the symbol file is specified AFTER
1169 the exec file is loaded (e.g., gdb -c core ; file foo).
1170 For dynamically linked executables, libpthread can be near the end
1171 of the list of shared libraries to load, and in an app of several
1172 thousand shared libraries, this can otherwise be painful. */
1173 && ((objfile
->flags
& OBJF_MAINLINE
) != 0
1174 || libpthread_name_p (objfile_name (objfile
))))
1175 check_for_thread_db ();
1179 check_pid_namespace_match (void)
1181 /* Check is only relevant for local targets targets. */
1182 if (target_can_run (¤t_target
))
1184 /* If the child is in a different PID namespace, its idea of its
1185 PID will differ from our idea of its PID. When we scan the
1186 child's thread list, we'll mistakenly think it has no threads
1187 since the thread PID fields won't match the PID we give to
1189 if (!linux_ns_same (ptid_get_pid (inferior_ptid
), LINUX_NS_PID
))
1191 warning (_ ("Target and debugger are in different PID "
1192 "namespaces; thread lists and other data are "
1193 "likely unreliable"));
1198 /* This function is called via the inferior_created observer.
1199 This handles the case of debugging statically linked executables. */
1202 thread_db_inferior_created (struct target_ops
*target
, int from_tty
)
1204 check_pid_namespace_match ();
1205 check_for_thread_db ();
1208 /* Update the thread's state (what's displayed in "info threads"),
1209 from libthread_db thread state information. */
1212 update_thread_state (struct private_thread_info
*priv
,
1213 const td_thrinfo_t
*ti_p
)
1215 priv
->dying
= (ti_p
->ti_state
== TD_THR_UNKNOWN
1216 || ti_p
->ti_state
== TD_THR_ZOMBIE
);
1219 /* Attach to a new thread. This function is called when we receive a
1220 TD_CREATE event or when we iterate over all threads and find one
1221 that wasn't already in our list. Returns true on success. */
1224 attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
1225 const td_thrinfo_t
*ti_p
)
1227 struct thread_info
*tp
;
1228 struct thread_db_info
*info
;
1230 /* If we're being called after a TD_CREATE event, we may already
1231 know about this thread. There are two ways this can happen. We
1232 may have iterated over all threads between the thread creation
1233 and the TD_CREATE event, for instance when the user has issued
1234 the `info threads' command before the SIGTRAP for hitting the
1235 thread creation breakpoint was reported. Alternatively, the
1236 thread may have exited and a new one been created with the same
1237 thread ID. In the first case we don't need to do anything; in
1238 the second case we should discard information about the dead
1239 thread and attach to the new one. */
1240 tp
= find_thread_ptid (ptid
);
1243 /* If tp->priv is NULL, then GDB is already attached to this
1244 thread, but we do not know anything about it. We can learn
1245 about it here. This can only happen if we have some other
1246 way besides libthread_db to notice new threads (i.e.
1247 PTRACE_EVENT_CLONE); assume the same mechanism notices thread
1248 exit, so this can not be a stale thread recreated with the
1250 if (tp
->priv
!= NULL
)
1252 if (!tp
->priv
->dying
)
1255 delete_thread (ptid
);
1260 /* Under GNU/Linux, we have to attach to each and every thread. */
1261 if (target_has_execution
1266 res
= lin_lwp_attach_lwp (ptid_build (ptid_get_pid (ptid
),
1270 /* Error, stop iterating. */
1275 /* Pretend this thread doesn't exist yet, and keep
1280 /* Otherwise, we sucessfully attached to the thread. */
1283 info
= get_thread_db_info (ptid_get_pid (ptid
));
1284 record_thread (info
, tp
, ptid
, th_p
, ti_p
);
1288 /* Record a new thread in GDB's thread list. Creates the thread's
1289 private info. If TP is NULL or TP is marked as having exited,
1290 creates a new thread. Otherwise, uses TP. */
1292 static struct thread_info
*
1293 record_thread (struct thread_db_info
*info
,
1294 struct thread_info
*tp
,
1295 ptid_t ptid
, const td_thrhandle_t
*th_p
,
1296 const td_thrinfo_t
*ti_p
)
1299 struct private_thread_info
*priv
;
1300 int new_thread
= (tp
== NULL
);
1302 /* A thread ID of zero may mean the thread library has not
1303 initialized yet. Leave private == NULL until the thread library
1305 if (ti_p
->ti_tid
== 0)
1308 /* Construct the thread's private data. */
1309 priv
= XCNEW (struct private_thread_info
);
1312 priv
->tid
= ti_p
->ti_tid
;
1313 update_thread_state (priv
, ti_p
);
1315 /* Add the thread to GDB's thread list. If we already know about a
1316 thread with this PTID, but it's marked exited, then the kernel
1317 reused the tid of an old thread. */
1318 if (tp
== NULL
|| tp
->state
== THREAD_EXITED
)
1319 tp
= add_thread_with_info (ptid
, priv
);
1323 /* Enable thread event reporting for this thread, except when
1324 debugging a core file. */
1325 if (target_has_execution
&& thread_db_use_events () && new_thread
)
1327 err
= info
->td_thr_event_enable_p (th_p
, 1);
1329 error (_("Cannot enable thread event reporting for %s: %s"),
1330 target_pid_to_str (ptid
), thread_db_err_str (err
));
1333 if (target_has_execution
)
1334 check_thread_signals ();
1340 detach_thread (ptid_t ptid
)
1342 struct thread_info
*thread_info
;
1344 /* Don't delete the thread now, because it still reports as active
1345 until it has executed a few instructions after the event
1346 breakpoint - if we deleted it now, "info threads" would cause us
1347 to re-attach to it. Just mark it as having had a TD_DEATH
1348 event. This means that we won't delete it from our thread list
1349 until we notice that it's dead (via prune_threads), or until
1350 something re-uses its thread ID. We'll report the thread exit
1351 when the underlying LWP dies. */
1352 thread_info
= find_thread_ptid (ptid
);
1353 gdb_assert (thread_info
!= NULL
&& thread_info
->priv
!= NULL
);
1354 thread_info
->priv
->dying
= 1;
1358 thread_db_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1360 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1361 struct thread_db_info
*info
;
1363 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1367 if (target_has_execution
&& thread_db_use_events ())
1369 disable_thread_event_reporting (info
);
1371 /* Delete the old thread event breakpoints. Note that
1372 unlike when mourning, we can remove them here because
1373 there's still a live inferior to poke at. In any case,
1374 GDB will not try to insert anything in the inferior when
1375 removing a breakpoint. */
1376 remove_thread_event_breakpoints ();
1379 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1382 target_beneath
->to_detach (target_beneath
, args
, from_tty
);
1384 /* NOTE: From this point on, inferior_ptid is null_ptid. */
1386 /* If there are no more processes using libpthread, detach the
1387 thread_db target ops. */
1388 if (!thread_db_list
)
1389 unpush_target (&thread_db_ops
);
1392 /* Check if PID is currently stopped at the location of a thread event
1393 breakpoint location. If it is, read the event message and act upon
1397 check_event (ptid_t ptid
)
1399 struct regcache
*regcache
= get_thread_regcache (ptid
);
1400 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
1406 struct thread_db_info
*info
;
1408 info
= get_thread_db_info (ptid_get_pid (ptid
));
1410 /* Bail out early if we're not at a thread event breakpoint. */
1411 stop_pc
= regcache_read_pc (regcache
);
1412 if (!target_supports_stopped_by_sw_breakpoint ())
1413 stop_pc
-= gdbarch_decr_pc_after_break (gdbarch
);
1415 if (stop_pc
!= info
->td_create_bp_addr
1416 && stop_pc
!= info
->td_death_bp_addr
)
1419 /* Access an lwp we know is stopped. */
1420 info
->proc_handle
.ptid
= ptid
;
1422 /* If we have only looked at the first thread before libpthread was
1423 initialized, we may not know its thread ID yet. Make sure we do
1424 before we add another thread to the list. */
1425 if (!have_threads (ptid
))
1426 thread_db_find_new_threads_1 (ptid
);
1428 /* If we are at a create breakpoint, we do not know what new lwp
1429 was created and cannot specifically locate the event message for it.
1430 We have to call td_ta_event_getmsg() to get
1431 the latest message. Since we have no way of correlating whether
1432 the event message we get back corresponds to our breakpoint, we must
1433 loop and read all event messages, processing them appropriately.
1434 This guarantees we will process the correct message before continuing
1435 from the breakpoint.
1437 Currently, death events are not enabled. If they are enabled,
1438 the death event can use the td_thr_event_getmsg() interface to
1439 get the message specifically for that lwp and avoid looping
1446 err
= info
->td_ta_event_getmsg_p (info
->thread_agent
, &msg
);
1449 if (err
== TD_NOMSG
)
1452 error (_("Cannot get thread event message: %s"),
1453 thread_db_err_str (err
));
1456 err
= info
->td_thr_get_info_p (msg
.th_p
, &ti
);
1458 error (_("Cannot get thread info: %s"), thread_db_err_str (err
));
1460 ptid
= ptid_build (ptid_get_pid (ptid
), ti
.ti_lid
, 0);
1465 /* Call attach_thread whether or not we already know about a
1466 thread with this thread ID. */
1467 attach_thread (ptid
, msg
.th_p
, &ti
);
1473 if (!in_thread_list (ptid
))
1474 error (_("Spurious thread death event."));
1476 detach_thread (ptid
);
1481 error (_("Spurious thread event."));
1488 thread_db_wait (struct target_ops
*ops
,
1489 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
1492 struct thread_db_info
*info
;
1493 struct target_ops
*beneath
= find_target_beneath (ops
);
1495 ptid
= beneath
->to_wait (beneath
, ptid
, ourstatus
, options
);
1497 if (ourstatus
->kind
== TARGET_WAITKIND_IGNORE
)
1500 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
1501 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
1504 info
= get_thread_db_info (ptid_get_pid (ptid
));
1506 /* If this process isn't using thread_db, we're done. */
1510 if (ourstatus
->kind
== TARGET_WAITKIND_EXECD
)
1512 /* New image, it may or may not end up using thread_db. Assume
1513 not unless we find otherwise. */
1514 delete_thread_db_info (ptid_get_pid (ptid
));
1515 if (!thread_db_list
)
1516 unpush_target (&thread_db_ops
);
1518 /* Thread event breakpoints are deleted by
1519 update_breakpoints_after_exec. */
1524 if (ourstatus
->kind
== TARGET_WAITKIND_STOPPED
1525 && ourstatus
->value
.sig
== GDB_SIGNAL_TRAP
)
1526 /* Check for a thread event. */
1529 /* Fill in the thread's user-level thread id and status. */
1530 thread_from_lwp (ptid
);
1536 thread_db_mourn_inferior (struct target_ops
*ops
)
1538 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1540 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1542 target_beneath
->to_mourn_inferior (target_beneath
);
1544 /* Delete the old thread event breakpoints. Do this after mourning
1545 the inferior, so that we don't try to uninsert them. */
1546 remove_thread_event_breakpoints ();
1548 /* Detach thread_db target ops. */
1549 if (!thread_db_list
)
1550 unpush_target (ops
);
1553 struct callback_data
1555 struct thread_db_info
*info
;
1560 find_new_threads_callback (const td_thrhandle_t
*th_p
, void *data
)
1565 struct thread_info
*tp
;
1566 struct callback_data
*cb_data
= data
;
1567 struct thread_db_info
*info
= cb_data
->info
;
1569 err
= info
->td_thr_get_info_p (th_p
, &ti
);
1571 error (_("find_new_threads_callback: cannot get thread info: %s"),
1572 thread_db_err_str (err
));
1574 if (ti
.ti_lid
== -1)
1576 /* A thread with kernel thread ID -1 is either a thread that
1577 exited and was joined, or a thread that is being created but
1578 hasn't started yet, and that is reusing the tcb/stack of a
1579 thread that previously exited and was joined. (glibc marks
1580 terminated and joined threads with kernel thread ID -1. See
1582 if (libthread_db_debug
)
1583 fprintf_unfiltered (gdb_stdlog
,
1584 "thread_db: skipping exited and "
1585 "joined thread (0x%lx)\n", ti
.ti_tid
);
1591 /* A thread ID of zero means that this is the main thread, but
1592 glibc has not yet initialized thread-local storage and the
1593 pthread library. We do not know what the thread's TID will
1594 be yet. Just enable event reporting and otherwise ignore
1597 /* In that case, we're not stopped in a fork syscall and don't
1598 need this glibc bug workaround. */
1599 info
->need_stale_parent_threads_check
= 0;
1601 if (target_has_execution
&& thread_db_use_events ())
1603 err
= info
->td_thr_event_enable_p (th_p
, 1);
1605 error (_("Cannot enable thread event reporting for LWP %d: %s"),
1606 (int) ti
.ti_lid
, thread_db_err_str (err
));
1612 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1613 bit expensive, as it needs to open /proc/pid/status, so try to
1614 avoid doing the work if we know we don't have to. */
1615 if (info
->need_stale_parent_threads_check
)
1617 int tgid
= linux_proc_get_tgid (ti
.ti_lid
);
1619 if (tgid
!= -1 && tgid
!= info
->pid
)
1623 ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
1624 tp
= find_thread_ptid (ptid
);
1625 if (tp
== NULL
|| tp
->priv
== NULL
)
1627 if (attach_thread (ptid
, th_p
, &ti
))
1628 cb_data
->new_threads
+= 1;
1630 /* Problem attaching this thread; perhaps it exited before we
1632 This could mean that the thread list inside glibc itself is in
1633 inconsistent state, and libthread_db could go on looping forever
1634 (observed with glibc-2.3.6). To prevent that, terminate
1635 iteration: thread_db_find_new_threads_2 will retry. */
1638 else if (target_has_execution
&& !thread_db_use_events ())
1640 /* Need to update this if not using the libthread_db events
1641 (particularly, the TD_DEATH event). */
1642 update_thread_state (tp
->priv
, &ti
);
1648 /* Helper for thread_db_find_new_threads_2.
1649 Returns number of new threads found. */
1652 find_new_threads_once (struct thread_db_info
*info
, int iteration
,
1655 struct callback_data data
;
1656 td_err_e err
= TD_ERR
;
1659 data
.new_threads
= 0;
1661 /* See comment in thread_db_update_thread_list. */
1662 gdb_assert (!target_has_execution
|| thread_db_use_events ());
1666 /* Iterate over all user-space threads to discover new threads. */
1667 err
= info
->td_ta_thr_iter_p (info
->thread_agent
,
1668 find_new_threads_callback
,
1671 TD_THR_LOWEST_PRIORITY
,
1673 TD_THR_ANY_USER_FLAGS
);
1675 CATCH (except
, RETURN_MASK_ERROR
)
1677 if (libthread_db_debug
)
1679 exception_fprintf (gdb_stdlog
, except
,
1680 "Warning: find_new_threads_once: ");
1685 if (libthread_db_debug
)
1687 fprintf_unfiltered (gdb_stdlog
,
1688 _("Found %d new threads in iteration %d.\n"),
1689 data
.new_threads
, iteration
);
1695 return data
.new_threads
;
1698 /* Search for new threads, accessing memory through stopped thread
1699 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1700 searches in a row do not discover any new threads. */
1703 thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
)
1705 td_err_e err
= TD_OK
;
1706 struct thread_db_info
*info
;
1709 info
= get_thread_db_info (ptid_get_pid (ptid
));
1711 /* Access an lwp we know is stopped. */
1712 info
->proc_handle
.ptid
= ptid
;
1716 /* Require 4 successive iterations which do not find any new threads.
1717 The 4 is a heuristic: there is an inherent race here, and I have
1718 seen that 2 iterations in a row are not always sufficient to
1719 "capture" all threads. */
1720 for (i
= 0, loop
= 0; loop
< 4 && err
== TD_OK
; ++i
, ++loop
)
1721 if (find_new_threads_once (info
, i
, &err
) != 0)
1723 /* Found some new threads. Restart the loop from beginning. */
1728 find_new_threads_once (info
, 0, &err
);
1731 error (_("Cannot find new threads: %s"), thread_db_err_str (err
));
1735 thread_db_find_new_threads_1 (ptid_t ptid
)
1737 thread_db_find_new_threads_2 (ptid
, 0);
1741 update_thread_core (struct lwp_info
*info
, void *closure
)
1743 info
->core
= linux_common_core_of_thread (info
->ptid
);
1747 /* Update the thread list using td_ta_thr_iter. */
1750 thread_db_update_thread_list_td_ta_thr_iter (struct target_ops
*ops
)
1752 struct thread_db_info
*info
;
1753 struct inferior
*inf
;
1759 struct thread_info
*thread
;
1764 info
= get_thread_db_info (inf
->pid
);
1768 thread
= any_live_thread_of_process (inf
->pid
);
1769 if (thread
== NULL
|| thread
->executing
)
1772 thread_db_find_new_threads_1 (thread
->ptid
);
1776 /* Implement the to_update_thread_list target method for this
1780 thread_db_update_thread_list (struct target_ops
*ops
)
1782 /* It's best to avoid td_ta_thr_iter if possible. That walks data
1783 structures in the inferior's address space that may be corrupted,
1784 or, if the target is running, the list may change while we walk
1785 it. In the latter case, it's possible that a thread exits just
1786 at the exact time that causes GDB to get stuck in an infinite
1787 loop. To avoid pausing all threads whenever the core wants to
1788 refresh the thread list, if the kernel supports clone events
1789 (meaning we're always already attached to all LWPs), we use
1790 thread_from_lwp immediately when we see an LWP stop. That uses
1791 thread_db entry points that do not walk libpthread's thread list,
1792 so should be safe, as well as more efficient. */
1793 if (target_has_execution
&& !thread_db_use_events ())
1794 ops
->beneath
->to_update_thread_list (ops
->beneath
);
1796 thread_db_update_thread_list_td_ta_thr_iter (ops
);
1798 if (target_has_execution
)
1799 iterate_over_lwps (minus_one_ptid
/* iterate over all */,
1800 update_thread_core
, NULL
);
1804 thread_db_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
1806 struct thread_info
*thread_info
= find_thread_ptid (ptid
);
1807 struct target_ops
*beneath
;
1809 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1811 static char buf
[64];
1814 tid
= thread_info
->priv
->tid
;
1815 snprintf (buf
, sizeof (buf
), "Thread 0x%lx (LWP %ld)",
1816 tid
, ptid_get_lwp (ptid
));
1821 beneath
= find_target_beneath (ops
);
1822 return beneath
->to_pid_to_str (beneath
, ptid
);
1825 /* Return a string describing the state of the thread specified by
1829 thread_db_extra_thread_info (struct target_ops
*self
,
1830 struct thread_info
*info
)
1832 if (info
->priv
== NULL
)
1835 if (info
->priv
->dying
)
1841 /* Get the address of the thread local variable in load module LM which
1842 is stored at OFFSET within the thread local storage for thread PTID. */
1845 thread_db_get_thread_local_address (struct target_ops
*ops
,
1850 struct thread_info
*thread_info
;
1851 struct target_ops
*beneath
;
1853 /* Find the matching thread. */
1854 thread_info
= find_thread_ptid (ptid
);
1856 /* We may not have discovered the thread yet. */
1857 if (thread_info
!= NULL
&& thread_info
->priv
== NULL
)
1858 thread_info
= thread_from_lwp (ptid
);
1860 if (thread_info
!= NULL
&& thread_info
->priv
!= NULL
)
1864 struct thread_db_info
*info
;
1866 info
= get_thread_db_info (ptid_get_pid (ptid
));
1868 /* Finally, get the address of the variable. */
1871 /* glibc doesn't provide the needed interface. */
1872 if (!info
->td_thr_tls_get_addr_p
)
1873 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR
,
1874 _("No TLS library support"));
1876 /* Note the cast through uintptr_t: this interface only works if
1877 a target address fits in a psaddr_t, which is a host pointer.
1878 So a 32-bit debugger can not access 64-bit TLS through this. */
1879 err
= info
->td_thr_tls_get_addr_p (&thread_info
->priv
->th
,
1880 (psaddr_t
)(uintptr_t) lm
,
1885 /* If glibc doesn't provide the needed interface throw an error
1886 that LM is zero - normally cases it should not be. */
1887 if (!info
->td_thr_tlsbase_p
)
1888 throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR
,
1889 _("TLS load module not found"));
1891 /* This code path handles the case of -static -pthread executables:
1892 https://sourceware.org/ml/libc-help/2014-03/msg00024.html
1893 For older GNU libc r_debug.r_map is NULL. For GNU libc after
1894 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
1895 The constant number 1 depends on GNU __libc_setup_tls
1896 initialization of l_tls_modid to 1. */
1897 err
= info
->td_thr_tlsbase_p (&thread_info
->priv
->th
,
1899 address
= (char *) address
+ offset
;
1902 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1903 /* The memory hasn't been allocated, yet. */
1904 if (err
== TD_NOTALLOC
)
1905 /* Now, if libthread_db provided the initialization image's
1906 address, we *could* try to build a non-lvalue value from
1907 the initialization image. */
1908 throw_error (TLS_NOT_ALLOCATED_YET_ERROR
,
1909 _("TLS not allocated yet"));
1912 /* Something else went wrong. */
1914 throw_error (TLS_GENERIC_ERROR
,
1915 (("%s")), thread_db_err_str (err
));
1917 /* Cast assuming host == target. Joy. */
1918 /* Do proper sign extension for the target. */
1919 gdb_assert (exec_bfd
);
1920 return (bfd_get_sign_extend_vma (exec_bfd
) > 0
1921 ? (CORE_ADDR
) (intptr_t) address
1922 : (CORE_ADDR
) (uintptr_t) address
);
1925 beneath
= find_target_beneath (ops
);
1926 return beneath
->to_get_thread_local_address (beneath
, ptid
, lm
, offset
);
1929 /* Implement the to_get_ada_task_ptid target method for this target. */
1932 thread_db_get_ada_task_ptid (struct target_ops
*self
, long lwp
, long thread
)
1934 /* NPTL uses a 1:1 model, so the LWP id suffices. */
1935 return ptid_build (ptid_get_pid (inferior_ptid
), lwp
, 0);
1939 thread_db_resume (struct target_ops
*ops
,
1940 ptid_t ptid
, int step
, enum gdb_signal signo
)
1942 struct target_ops
*beneath
= find_target_beneath (ops
);
1943 struct thread_db_info
*info
;
1945 if (ptid_equal (ptid
, minus_one_ptid
))
1946 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1948 info
= get_thread_db_info (ptid_get_pid (ptid
));
1950 /* This workaround is only needed for child fork lwps stopped in a
1951 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1952 workaround can be disabled. */
1954 info
->need_stale_parent_threads_check
= 0;
1956 beneath
->to_resume (beneath
, ptid
, step
, signo
);
1959 /* qsort helper function for info_auto_load_libthread_db, sort the
1960 thread_db_info pointers primarily by their FILENAME and secondarily by their
1961 PID, both in ascending order. */
1964 info_auto_load_libthread_db_compare (const void *ap
, const void *bp
)
1966 struct thread_db_info
*a
= *(struct thread_db_info
**) ap
;
1967 struct thread_db_info
*b
= *(struct thread_db_info
**) bp
;
1970 retval
= strcmp (a
->filename
, b
->filename
);
1974 return (a
->pid
> b
->pid
) - (a
->pid
- b
->pid
);
1977 /* Implement 'info auto-load libthread-db'. */
1980 info_auto_load_libthread_db (char *args
, int from_tty
)
1982 struct ui_out
*uiout
= current_uiout
;
1983 const char *cs
= args
? args
: "";
1984 struct thread_db_info
*info
, **array
;
1985 unsigned info_count
, unique_filenames
;
1986 size_t max_filename_len
, max_pids_len
, pids_len
;
1987 struct cleanup
*back_to
;
1991 cs
= skip_spaces_const (cs
);
1993 error (_("'info auto-load libthread-db' does not accept any parameters"));
1996 for (info
= thread_db_list
; info
; info
= info
->next
)
1997 if (info
->filename
!= NULL
)
2000 array
= XNEWVEC (struct thread_db_info
*, info_count
);
2001 back_to
= make_cleanup (xfree
, array
);
2004 for (info
= thread_db_list
; info
; info
= info
->next
)
2005 if (info
->filename
!= NULL
)
2006 array
[info_count
++] = info
;
2008 /* Sort ARRAY by filenames and PIDs. */
2010 qsort (array
, info_count
, sizeof (*array
),
2011 info_auto_load_libthread_db_compare
);
2013 /* Calculate the number of unique filenames (rows) and the maximum string
2014 length of PIDs list for the unique filenames (columns). */
2016 unique_filenames
= 0;
2017 max_filename_len
= 0;
2020 for (i
= 0; i
< info_count
; i
++)
2022 int pid
= array
[i
]->pid
;
2023 size_t this_pid_len
;
2025 for (this_pid_len
= 0; pid
!= 0; pid
/= 10)
2028 if (i
== 0 || strcmp (array
[i
- 1]->filename
, array
[i
]->filename
) != 0)
2031 max_filename_len
= max (max_filename_len
,
2032 strlen (array
[i
]->filename
));
2036 pids_len
-= strlen (", ");
2037 max_pids_len
= max (max_pids_len
, pids_len
);
2041 pids_len
+= this_pid_len
+ strlen (", ");
2045 pids_len
-= strlen (", ");
2046 max_pids_len
= max (max_pids_len
, pids_len
);
2049 /* Table header shifted right by preceding "libthread-db: " would not match
2051 if (info_count
> 0 && args
== auto_load_info_scripts_pattern_nl
)
2052 ui_out_text (uiout
, "\n");
2054 make_cleanup_ui_out_table_begin_end (uiout
, 2, unique_filenames
,
2055 "LinuxThreadDbTable");
2057 ui_out_table_header (uiout
, max_filename_len
, ui_left
, "filename",
2059 ui_out_table_header (uiout
, pids_len
, ui_left
, "PIDs", "Pids");
2060 ui_out_table_body (uiout
);
2062 pids
= xmalloc (max_pids_len
+ 1);
2063 make_cleanup (xfree
, pids
);
2065 /* Note I is incremented inside the cycle, not at its end. */
2066 for (i
= 0; i
< info_count
;)
2068 struct cleanup
*chain
= make_cleanup_ui_out_tuple_begin_end (uiout
, NULL
);
2072 ui_out_field_string (uiout
, "filename", info
->filename
);
2075 while (i
< info_count
&& strcmp (info
->filename
, array
[i
]->filename
) == 0)
2077 if (pids_end
!= pids
)
2082 pids_end
+= xsnprintf (pids_end
, &pids
[max_pids_len
+ 1] - pids_end
,
2083 "%u", array
[i
]->pid
);
2084 gdb_assert (pids_end
< &pids
[max_pids_len
+ 1]);
2090 ui_out_field_string (uiout
, "pids", pids
);
2092 ui_out_text (uiout
, "\n");
2093 do_cleanups (chain
);
2096 do_cleanups (back_to
);
2098 if (info_count
== 0)
2099 ui_out_message (uiout
, 0, _("No auto-loaded libthread-db.\n"));
2103 init_thread_db_ops (void)
2105 thread_db_ops
.to_shortname
= "multi-thread";
2106 thread_db_ops
.to_longname
= "multi-threaded child process.";
2107 thread_db_ops
.to_doc
= "Threads and pthreads support.";
2108 thread_db_ops
.to_detach
= thread_db_detach
;
2109 thread_db_ops
.to_wait
= thread_db_wait
;
2110 thread_db_ops
.to_resume
= thread_db_resume
;
2111 thread_db_ops
.to_mourn_inferior
= thread_db_mourn_inferior
;
2112 thread_db_ops
.to_update_thread_list
= thread_db_update_thread_list
;
2113 thread_db_ops
.to_pid_to_str
= thread_db_pid_to_str
;
2114 thread_db_ops
.to_stratum
= thread_stratum
;
2115 thread_db_ops
.to_has_thread_control
= tc_schedlock
;
2116 thread_db_ops
.to_get_thread_local_address
2117 = thread_db_get_thread_local_address
;
2118 thread_db_ops
.to_extra_thread_info
= thread_db_extra_thread_info
;
2119 thread_db_ops
.to_get_ada_task_ptid
= thread_db_get_ada_task_ptid
;
2120 thread_db_ops
.to_magic
= OPS_MAGIC
;
2122 complete_target_initialization (&thread_db_ops
);
2125 /* Provide a prototype to silence -Wmissing-prototypes. */
2126 extern initialize_file_ftype _initialize_thread_db
;
2129 _initialize_thread_db (void)
2131 init_thread_db_ops ();
2133 /* Defer loading of libthread_db.so until inferior is running.
2134 This allows gdb to load correct libthread_db for a given
2135 executable -- there could be mutiple versions of glibc,
2136 compiled with LinuxThreads or NPTL, and until there is
2137 a running inferior, we can't tell which libthread_db is
2138 the correct one to load. */
2140 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
2142 add_setshow_optional_filename_cmd ("libthread-db-search-path",
2144 &libthread_db_search_path
, _("\
2145 Set search path for libthread_db."), _("\
2146 Show the current search path or libthread_db."), _("\
2147 This path is used to search for libthread_db to be loaded into \
2149 Its value is a colon (':') separate list of directories to search.\n\
2150 Setting the search path to an empty list resets it to its default value."),
2151 set_libthread_db_search_path
,
2153 &setlist
, &showlist
);
2155 add_setshow_zuinteger_cmd ("libthread-db", class_maintenance
,
2156 &libthread_db_debug
, _("\
2157 Set libthread-db debugging."), _("\
2158 Show libthread-db debugging."), _("\
2159 When non-zero, libthread-db debugging is enabled."),
2161 show_libthread_db_debug
,
2162 &setdebuglist
, &showdebuglist
);
2164 add_setshow_boolean_cmd ("libthread-db", class_support
,
2165 &auto_load_thread_db
, _("\
2166 Enable or disable auto-loading of inferior specific libthread_db."), _("\
2167 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
2168 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
2169 locations to load libthread_db compatible with the inferior.\n\
2170 Standard system libthread_db still gets loaded even with this option off.\n\
2171 This options has security implications for untrusted inferiors."),
2172 NULL
, show_auto_load_thread_db
,
2173 auto_load_set_cmdlist_get (),
2174 auto_load_show_cmdlist_get ());
2176 add_cmd ("libthread-db", class_info
, info_auto_load_libthread_db
,
2177 _("Print the list of loaded inferior specific libthread_db.\n\
2178 Usage: info auto-load libthread-db"),
2179 auto_load_info_cmdlist_get ());
2181 /* Add ourselves to objfile event chain. */
2182 observer_attach_new_objfile (thread_db_new_objfile
);
2184 /* Add ourselves to inferior_created event chain.
2185 This is needed to handle debugging statically linked programs where
2186 the new_objfile observer won't get called for libpthread. */
2187 observer_attach_inferior_created (thread_db_inferior_created
);