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"
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_err_e (*td_init_p
) (void);
179 td_err_e (*td_ta_new_p
) (struct ps_prochandle
* ps
,
181 td_err_e (*td_ta_map_id2thr_p
) (const td_thragent_t
*ta
, thread_t pt
,
182 td_thrhandle_t
*__th
);
183 td_err_e (*td_ta_map_lwp2thr_p
) (const td_thragent_t
*ta
,
184 lwpid_t lwpid
, td_thrhandle_t
*th
);
185 td_err_e (*td_ta_thr_iter_p
) (const td_thragent_t
*ta
,
186 td_thr_iter_f
*callback
, void *cbdata_p
,
187 td_thr_state_e state
, int ti_pri
,
188 sigset_t
*ti_sigmask_p
,
189 unsigned int ti_user_flags
);
190 td_err_e (*td_ta_event_addr_p
) (const td_thragent_t
*ta
,
191 td_event_e event
, td_notify_t
*ptr
);
192 td_err_e (*td_ta_set_event_p
) (const td_thragent_t
*ta
,
193 td_thr_events_t
*event
);
194 td_err_e (*td_ta_clear_event_p
) (const td_thragent_t
*ta
,
195 td_thr_events_t
*event
);
196 td_err_e (*td_ta_event_getmsg_p
) (const td_thragent_t
*ta
,
197 td_event_msg_t
*msg
);
199 td_err_e (*td_thr_validate_p
) (const td_thrhandle_t
*th
);
200 td_err_e (*td_thr_get_info_p
) (const td_thrhandle_t
*th
,
201 td_thrinfo_t
*infop
);
202 td_err_e (*td_thr_event_enable_p
) (const td_thrhandle_t
*th
,
205 td_err_e (*td_thr_tls_get_addr_p
) (const td_thrhandle_t
*th
,
206 psaddr_t map_address
,
207 size_t offset
, psaddr_t
*address
);
208 td_err_e (*td_thr_tlsbase_p
) (const td_thrhandle_t
*th
,
209 unsigned long int modid
,
213 /* List of known processes using thread_db, and the required
215 struct thread_db_info
*thread_db_list
;
217 static void thread_db_find_new_threads_1 (ptid_t ptid
);
218 static void thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
);
220 /* Add the current inferior to the list of processes using libpthread.
221 Return a pointer to the newly allocated object that was added to
222 THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
225 static struct thread_db_info
*
226 add_thread_db_info (void *handle
)
228 struct thread_db_info
*info
;
230 info
= xcalloc (1, sizeof (*info
));
231 info
->pid
= ptid_get_pid (inferior_ptid
);
232 info
->handle
= handle
;
234 /* The workaround works by reading from /proc/pid/status, so it is
235 disabled for core files. */
236 if (target_has_execution
)
237 info
->need_stale_parent_threads_check
= 1;
239 info
->next
= thread_db_list
;
240 thread_db_list
= info
;
245 /* Return the thread_db_info object representing the bookkeeping
246 related to process PID, if any; NULL otherwise. */
248 static struct thread_db_info
*
249 get_thread_db_info (int pid
)
251 struct thread_db_info
*info
;
253 for (info
= thread_db_list
; info
; info
= info
->next
)
254 if (pid
== info
->pid
)
260 /* When PID has exited or has been detached, we no longer want to keep
261 track of it as using libpthread. Call this function to discard
262 thread_db related info related to PID. Note that this closes
263 LIBTHREAD_DB_SO's dlopen'ed handle. */
266 delete_thread_db_info (int pid
)
268 struct thread_db_info
*info
, *info_prev
;
272 for (info
= thread_db_list
; info
; info_prev
= info
, info
= info
->next
)
273 if (pid
== info
->pid
)
279 if (info
->handle
!= NULL
)
280 dlclose (info
->handle
);
282 xfree (info
->filename
);
285 info_prev
->next
= info
->next
;
287 thread_db_list
= info
->next
;
292 /* Prototypes for local functions. */
293 static int attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
294 const td_thrinfo_t
*ti_p
);
295 static void detach_thread (ptid_t ptid
);
298 /* Use "struct private_thread_info" to cache thread state. This is
299 a substantial optimization. */
301 struct private_thread_info
303 /* Flag set when we see a TD_DEATH event for this thread. */
304 unsigned int dying
:1;
306 /* Cached thread state. */
313 thread_db_err_str (td_err_e err
)
320 return "generic 'call succeeded'";
322 return "generic error";
324 return "no thread to satisfy query";
326 return "no sync handle to satisfy query";
328 return "no LWP to satisfy query";
330 return "invalid process handle";
332 return "invalid thread handle";
334 return "invalid synchronization handle";
336 return "invalid thread agent";
338 return "invalid key";
340 return "no event message for getmsg";
342 return "FPU register set not available";
344 return "application not linked with libthread";
346 return "requested event is not supported";
348 return "capability not available";
350 return "debugger service failed";
352 return "operation not applicable to";
354 return "no thread-specific data for this thread";
356 return "malloc failed";
358 return "only part of register set was written/read";
360 return "X register set not available for this thread";
361 #ifdef THREAD_DB_HAS_TD_NOTALLOC
363 return "thread has not yet allocated TLS for given module";
365 #ifdef THREAD_DB_HAS_TD_VERSION
367 return "versions of libpthread and libthread_db do not match";
369 #ifdef THREAD_DB_HAS_TD_NOTLS
371 return "there is no TLS segment in the given module";
374 snprintf (buf
, sizeof (buf
), "unknown thread_db error '%d'", err
);
379 /* Return 1 if any threads have been registered. There may be none if
380 the threading library is not fully initialized yet. */
383 have_threads_callback (struct thread_info
*thread
, void *args
)
385 int pid
= * (int *) args
;
387 if (ptid_get_pid (thread
->ptid
) != pid
)
390 return thread
->private != NULL
;
394 have_threads (ptid_t ptid
)
396 int pid
= ptid_get_pid (ptid
);
398 return iterate_over_threads (have_threads_callback
, &pid
) != NULL
;
401 struct thread_get_info_inout
403 struct thread_info
*thread_info
;
404 struct thread_db_info
*thread_db_info
;
407 /* A callback function for td_ta_thr_iter, which we use to map all
410 THP is a handle to the current thread; if INFOP is not NULL, the
411 struct thread_info associated with this thread is returned in
414 If the thread is a zombie, TD_THR_ZOMBIE is returned. Otherwise,
415 zero is returned to indicate success. */
418 thread_get_info_callback (const td_thrhandle_t
*thp
, void *argp
)
423 struct thread_get_info_inout
*inout
;
424 struct thread_db_info
*info
;
427 info
= inout
->thread_db_info
;
429 err
= info
->td_thr_get_info_p (thp
, &ti
);
431 error (_("thread_get_info_callback: cannot get thread info: %s"),
432 thread_db_err_str (err
));
436 /* We'll get this if a threaded program has a thread call clone
437 with CLONE_VM. `clone' sets the pthread LID of the new LWP
438 to -1, which ends up clearing the parent thread's LID. */
442 /* Fill the cache. */
443 thread_ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
444 inout
->thread_info
= find_thread_ptid (thread_ptid
);
446 if (inout
->thread_info
== NULL
)
448 /* New thread. Attach to it now (why wait?). */
449 if (!have_threads (thread_ptid
))
450 thread_db_find_new_threads_1 (thread_ptid
);
452 attach_thread (thread_ptid
, thp
, &ti
);
453 inout
->thread_info
= find_thread_ptid (thread_ptid
);
454 gdb_assert (inout
->thread_info
!= NULL
);
460 /* Fetch the user-level thread id of PTID. */
463 thread_from_lwp (ptid_t ptid
)
467 struct thread_db_info
*info
;
468 struct thread_get_info_inout io
= {0};
470 /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
473 /* This ptid comes from linux-nat.c, which should always fill in the
475 gdb_assert (ptid_get_lwp (ptid
) != 0);
477 info
= get_thread_db_info (ptid_get_pid (ptid
));
479 /* Access an lwp we know is stopped. */
480 info
->proc_handle
.ptid
= ptid
;
481 err
= info
->td_ta_map_lwp2thr_p (info
->thread_agent
, ptid_get_lwp (ptid
),
484 error (_("Cannot find user-level thread for LWP %ld: %s"),
485 ptid_get_lwp (ptid
), thread_db_err_str (err
));
487 /* Long-winded way of fetching the thread info. */
488 io
.thread_db_info
= info
;
489 io
.thread_info
= NULL
;
490 thread_get_info_callback (&th
, &io
);
494 /* Attach to lwp PTID, doing whatever else is required to have this
495 LWP under the debugger's control --- e.g., enabling event
496 reporting. Returns true on success. */
498 thread_db_attach_lwp (ptid_t ptid
)
503 struct thread_db_info
*info
;
505 info
= get_thread_db_info (ptid_get_pid (ptid
));
510 /* This ptid comes from linux-nat.c, which should always fill in the
512 gdb_assert (ptid_get_lwp (ptid
) != 0);
514 /* Access an lwp we know is stopped. */
515 info
->proc_handle
.ptid
= ptid
;
517 /* If we have only looked at the first thread before libpthread was
518 initialized, we may not know its thread ID yet. Make sure we do
519 before we add another thread to the list. */
520 if (!have_threads (ptid
))
521 thread_db_find_new_threads_1 (ptid
);
523 err
= info
->td_ta_map_lwp2thr_p (info
->thread_agent
, ptid_get_lwp (ptid
),
526 /* Cannot find user-level thread. */
529 err
= info
->td_thr_get_info_p (&th
, &ti
);
532 warning (_("Cannot get thread info: %s"), thread_db_err_str (err
));
536 attach_thread (ptid
, &th
, &ti
);
541 verbose_dlsym (void *handle
, const char *name
)
543 void *sym
= dlsym (handle
, name
);
545 warning (_("Symbol \"%s\" not found in libthread_db: %s"),
551 enable_thread_event (int event
, CORE_ADDR
*bp
)
555 struct thread_db_info
*info
;
557 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
559 /* Access an lwp we know is stopped. */
560 info
->proc_handle
.ptid
= inferior_ptid
;
562 /* Get the breakpoint address for thread EVENT. */
563 err
= info
->td_ta_event_addr_p (info
->thread_agent
, event
, ¬ify
);
567 /* Set up the breakpoint. */
568 gdb_assert (exec_bfd
);
569 (*bp
) = (gdbarch_convert_from_func_ptr_addr
571 /* Do proper sign extension for the target. */
572 (bfd_get_sign_extend_vma (exec_bfd
) > 0
573 ? (CORE_ADDR
) (intptr_t) notify
.u
.bptaddr
574 : (CORE_ADDR
) (uintptr_t) notify
.u
.bptaddr
),
576 create_thread_event_breakpoint (target_gdbarch (), *bp
);
581 /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
582 return 1 if this version is lower (and not equal) to
583 VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
586 inferior_has_bug (const char *ver_symbol
, int ver_major_min
, int ver_minor_min
)
588 struct bound_minimal_symbol version_msym
;
589 CORE_ADDR version_addr
;
591 int err
, got
, retval
= 0;
593 version_msym
= lookup_minimal_symbol (ver_symbol
, NULL
, NULL
);
594 if (version_msym
.minsym
== NULL
)
597 version_addr
= BMSYMBOL_VALUE_ADDRESS (version_msym
);
598 got
= target_read_string (version_addr
, &version
, 32, &err
);
599 if (err
== 0 && memchr (version
, 0, got
) == &version
[got
-1])
603 retval
= (sscanf (version
, "%d.%d", &major
, &minor
) == 2
604 && (major
< ver_major_min
605 || (major
== ver_major_min
&& minor
< ver_minor_min
)));
613 enable_thread_event_reporting (void)
615 td_thr_events_t events
;
617 struct thread_db_info
*info
;
619 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
621 /* We cannot use the thread event reporting facility if these
622 functions aren't available. */
623 if (info
->td_ta_event_addr_p
== NULL
624 || info
->td_ta_set_event_p
== NULL
625 || info
->td_ta_event_getmsg_p
== NULL
626 || info
->td_thr_event_enable_p
== NULL
)
629 /* Set the process wide mask saying which events we're interested in. */
630 td_event_emptyset (&events
);
631 td_event_addset (&events
, TD_CREATE
);
633 /* There is a bug fixed between linuxthreads 2.1.3 and 2.2 by
634 commit 2e4581e4fba917f1779cd0a010a45698586c190a
635 * manager.c (pthread_exited): Correctly report event as TD_REAP
636 instead of TD_DEATH. Fix comments.
637 where event reporting facility is broken for TD_DEATH events,
638 so don't enable it if we have glibc but a lower version. */
639 if (!inferior_has_bug ("__linuxthreads_version", 2, 2))
640 td_event_addset (&events
, TD_DEATH
);
642 err
= info
->td_ta_set_event_p (info
->thread_agent
, &events
);
645 warning (_("Unable to set global thread event mask: %s"),
646 thread_db_err_str (err
));
650 /* Delete previous thread event breakpoints, if any. */
651 remove_thread_event_breakpoints ();
652 info
->td_create_bp_addr
= 0;
653 info
->td_death_bp_addr
= 0;
655 /* Set up the thread creation event. */
656 err
= enable_thread_event (TD_CREATE
, &info
->td_create_bp_addr
);
659 warning (_("Unable to get location for thread creation breakpoint: %s"),
660 thread_db_err_str (err
));
664 /* Set up the thread death event. */
665 err
= enable_thread_event (TD_DEATH
, &info
->td_death_bp_addr
);
668 warning (_("Unable to get location for thread death breakpoint: %s"),
669 thread_db_err_str (err
));
674 /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
677 Return 1 if the caller should abort libthread_db initialization. Return 0
681 thread_db_find_new_threads_silently (ptid_t ptid
)
683 volatile struct gdb_exception except
;
685 TRY_CATCH (except
, RETURN_MASK_ERROR
)
687 thread_db_find_new_threads_2 (ptid
, 1);
690 if (except
.reason
< 0)
692 if (libthread_db_debug
)
693 exception_fprintf (gdb_stdlog
, except
,
694 "Warning: thread_db_find_new_threads_silently: ");
696 /* There is a bug fixed between nptl 2.6.1 and 2.7 by
697 commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
698 where calls to td_thr_get_info fail with TD_ERR for statically linked
699 executables if td_thr_get_info is called before glibc has initialized
702 If the nptl bug is NOT present in the inferior and still thread_db
703 reports an error return 1. It means the inferior has corrupted thread
704 list and GDB should fall back only to LWPs.
706 If the nptl bug is present in the inferior return 0 to silently ignore
707 such errors, and let gdb enumerate threads again later. In such case
708 GDB cannot properly display LWPs if the inferior thread list is
709 corrupted. For core files it does not apply, no 'later enumeration'
712 if (!target_has_execution
|| !inferior_has_bug ("nptl_version", 2, 7))
714 exception_fprintf (gdb_stderr
, except
,
715 _("Warning: couldn't activate thread debugging "
716 "using libthread_db: "));
723 /* Lookup a library in which given symbol resides.
724 Note: this is looking in GDB process, not in the inferior.
725 Returns library name, or NULL. */
728 dladdr_to_soname (const void *addr
)
732 if (dladdr (addr
, &info
) != 0)
733 return info
.dli_fname
;
737 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
739 Failure could happen if libthread_db does not have symbols we expect,
740 or when it refuses to work with the current inferior (e.g. due to
741 version mismatch between libthread_db and libpthread). */
744 try_thread_db_load_1 (struct thread_db_info
*info
)
748 /* Initialize pointers to the dynamic library functions we will use.
749 Essential functions first. */
751 info
->td_init_p
= verbose_dlsym (info
->handle
, "td_init");
752 if (info
->td_init_p
== NULL
)
755 err
= info
->td_init_p ();
758 warning (_("Cannot initialize libthread_db: %s"),
759 thread_db_err_str (err
));
763 info
->td_ta_new_p
= verbose_dlsym (info
->handle
, "td_ta_new");
764 if (info
->td_ta_new_p
== NULL
)
767 /* Initialize the structure that identifies the child process. */
768 info
->proc_handle
.ptid
= inferior_ptid
;
770 /* Now attempt to open a connection to the thread library. */
771 err
= info
->td_ta_new_p (&info
->proc_handle
, &info
->thread_agent
);
774 if (libthread_db_debug
)
775 fprintf_unfiltered (gdb_stdlog
, _("td_ta_new failed: %s\n"),
776 thread_db_err_str (err
));
781 #ifdef THREAD_DB_HAS_TD_VERSION
784 /* The errors above are not unexpected and silently ignored:
785 they just mean we haven't found correct version of
789 warning (_("td_ta_new failed: %s"), thread_db_err_str (err
));
794 info
->td_ta_map_id2thr_p
= verbose_dlsym (info
->handle
, "td_ta_map_id2thr");
795 if (info
->td_ta_map_id2thr_p
== NULL
)
798 info
->td_ta_map_lwp2thr_p
= verbose_dlsym (info
->handle
,
799 "td_ta_map_lwp2thr");
800 if (info
->td_ta_map_lwp2thr_p
== NULL
)
803 info
->td_ta_thr_iter_p
= verbose_dlsym (info
->handle
, "td_ta_thr_iter");
804 if (info
->td_ta_thr_iter_p
== NULL
)
807 info
->td_thr_validate_p
= verbose_dlsym (info
->handle
, "td_thr_validate");
808 if (info
->td_thr_validate_p
== NULL
)
811 info
->td_thr_get_info_p
= verbose_dlsym (info
->handle
, "td_thr_get_info");
812 if (info
->td_thr_get_info_p
== NULL
)
815 /* These are not essential. */
816 info
->td_ta_event_addr_p
= dlsym (info
->handle
, "td_ta_event_addr");
817 info
->td_ta_set_event_p
= dlsym (info
->handle
, "td_ta_set_event");
818 info
->td_ta_clear_event_p
= dlsym (info
->handle
, "td_ta_clear_event");
819 info
->td_ta_event_getmsg_p
= dlsym (info
->handle
, "td_ta_event_getmsg");
820 info
->td_thr_event_enable_p
= dlsym (info
->handle
, "td_thr_event_enable");
821 info
->td_thr_tls_get_addr_p
= dlsym (info
->handle
, "td_thr_tls_get_addr");
822 info
->td_thr_tlsbase_p
= dlsym (info
->handle
, "td_thr_tlsbase");
824 if (thread_db_find_new_threads_silently (inferior_ptid
) != 0)
826 /* Even if libthread_db initializes, if the thread list is
827 corrupted, we'd not manage to list any threads. Better reject this
828 thread_db, and fall back to at least listing LWPs. */
832 printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
834 if (*libthread_db_search_path
|| libthread_db_debug
)
836 struct ui_file
*file
;
839 library
= dladdr_to_soname (*info
->td_ta_new_p
);
841 library
= LIBTHREAD_DB_SO
;
843 /* If we'd print this to gdb_stdout when debug output is
844 disabled, still print it to gdb_stdout if debug output is
845 enabled. User visible output should not depend on debug
847 file
= *libthread_db_search_path
!= '\0' ? gdb_stdout
: gdb_stdlog
;
848 fprintf_unfiltered (file
, _("Using host libthread_db library \"%s\".\n"),
852 /* The thread library was detected. Activate the thread_db target
853 if this is the first process using it. */
854 if (thread_db_list
->next
== NULL
)
855 push_target (&thread_db_ops
);
857 /* Enable event reporting, but not when debugging a core file. */
858 if (target_has_execution
&& thread_db_use_events ())
859 enable_thread_event_reporting ();
864 /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
865 relative, or just LIBTHREAD_DB. */
868 try_thread_db_load (const char *library
, int check_auto_load_safe
)
871 struct thread_db_info
*info
;
873 if (libthread_db_debug
)
874 fprintf_unfiltered (gdb_stdlog
,
875 _("Trying host libthread_db library: %s.\n"),
878 if (check_auto_load_safe
)
880 if (access (library
, R_OK
) != 0)
882 /* Do not print warnings by file_is_auto_load_safe if the library does
883 not exist at this place. */
884 if (libthread_db_debug
)
885 fprintf_unfiltered (gdb_stdlog
, _("open failed: %s.\n"),
886 safe_strerror (errno
));
890 if (!file_is_auto_load_safe (library
, _("auto-load: Loading libthread-db "
891 "library \"%s\" from explicit "
897 handle
= dlopen (library
, RTLD_NOW
);
900 if (libthread_db_debug
)
901 fprintf_unfiltered (gdb_stdlog
, _("dlopen failed: %s.\n"), dlerror ());
905 if (libthread_db_debug
&& strchr (library
, '/') == NULL
)
909 td_init
= dlsym (handle
, "td_init");
912 const char *const libpath
= dladdr_to_soname (td_init
);
915 fprintf_unfiltered (gdb_stdlog
, _("Host %s resolved to: %s.\n"),
920 info
= add_thread_db_info (handle
);
922 /* Do not save system library name, that one is always trusted. */
923 if (strchr (library
, '/') != NULL
)
924 info
->filename
= gdb_realpath (library
);
926 if (try_thread_db_load_1 (info
))
929 /* This library "refused" to work on current inferior. */
930 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
934 /* Subroutine of try_thread_db_load_from_pdir to simplify it.
935 Try loading libthread_db in directory(OBJ)/SUBDIR.
936 SUBDIR may be NULL. It may also be something like "../lib64".
937 The result is true for success. */
940 try_thread_db_load_from_pdir_1 (struct objfile
*obj
, const char *subdir
)
942 struct cleanup
*cleanup
;
945 const char *obj_name
= objfile_name (obj
);
947 if (obj_name
[0] != '/')
949 warning (_("Expected absolute pathname for libpthread in the"
950 " inferior, but got %s."), obj_name
);
954 path
= xmalloc (strlen (obj_name
) + (subdir
? strlen (subdir
) + 1 : 0)
955 + 1 + strlen (LIBTHREAD_DB_SO
) + 1);
956 cleanup
= make_cleanup (xfree
, path
);
958 strcpy (path
, obj_name
);
959 cp
= strrchr (path
, '/');
960 /* This should at minimum hit the first character. */
961 gdb_assert (cp
!= NULL
);
968 strcat (cp
, LIBTHREAD_DB_SO
);
970 result
= try_thread_db_load (path
, 1);
972 do_cleanups (cleanup
);
976 /* Handle $pdir in libthread-db-search-path.
977 Look for libthread_db in directory(libpthread)/SUBDIR.
978 SUBDIR may be NULL. It may also be something like "../lib64".
979 The result is true for success. */
982 try_thread_db_load_from_pdir (const char *subdir
)
986 if (!auto_load_thread_db
)
990 if (libpthread_name_p (objfile_name (obj
)))
992 if (try_thread_db_load_from_pdir_1 (obj
, subdir
))
995 /* We may have found the separate-debug-info version of
996 libpthread, and it may live in a directory without a matching
998 if (obj
->separate_debug_objfile_backlink
!= NULL
)
999 return try_thread_db_load_from_pdir_1 (obj
->separate_debug_objfile_backlink
,
1008 /* Handle $sdir in libthread-db-search-path.
1009 Look for libthread_db in the system dirs, or wherever a plain
1010 dlopen(file_without_path) will look.
1011 The result is true for success. */
1014 try_thread_db_load_from_sdir (void)
1016 return try_thread_db_load (LIBTHREAD_DB_SO
, 0);
1019 /* Try to load libthread_db from directory DIR of length DIR_LEN.
1020 The result is true for success. */
1023 try_thread_db_load_from_dir (const char *dir
, size_t dir_len
)
1025 struct cleanup
*cleanup
;
1029 if (!auto_load_thread_db
)
1032 path
= xmalloc (dir_len
+ 1 + strlen (LIBTHREAD_DB_SO
) + 1);
1033 cleanup
= make_cleanup (xfree
, path
);
1035 memcpy (path
, dir
, dir_len
);
1036 path
[dir_len
] = '/';
1037 strcpy (path
+ dir_len
+ 1, LIBTHREAD_DB_SO
);
1039 result
= try_thread_db_load (path
, 1);
1041 do_cleanups (cleanup
);
1045 /* Search libthread_db_search_path for libthread_db which "agrees"
1046 to work on current inferior.
1047 The result is true for success. */
1050 thread_db_load_search (void)
1052 VEC (char_ptr
) *dir_vec
;
1053 struct cleanup
*cleanups
;
1057 dir_vec
= dirnames_to_char_ptr_vec (libthread_db_search_path
);
1058 cleanups
= make_cleanup_free_char_ptr_vec (dir_vec
);
1060 for (i
= 0; VEC_iterate (char_ptr
, dir_vec
, i
, this_dir
); ++i
)
1062 const int pdir_len
= sizeof ("$pdir") - 1;
1063 size_t this_dir_len
;
1065 this_dir_len
= strlen (this_dir
);
1067 if (strncmp (this_dir
, "$pdir", pdir_len
) == 0
1068 && (this_dir
[pdir_len
] == '\0'
1069 || this_dir
[pdir_len
] == '/'))
1071 char *subdir
= NULL
;
1072 struct cleanup
*free_subdir_cleanup
1073 = make_cleanup (null_cleanup
, NULL
);
1075 if (this_dir
[pdir_len
] == '/')
1077 subdir
= xmalloc (strlen (this_dir
));
1078 make_cleanup (xfree
, subdir
);
1079 strcpy (subdir
, this_dir
+ pdir_len
+ 1);
1081 rc
= try_thread_db_load_from_pdir (subdir
);
1082 do_cleanups (free_subdir_cleanup
);
1086 else if (strcmp (this_dir
, "$sdir") == 0)
1088 if (try_thread_db_load_from_sdir ())
1096 if (try_thread_db_load_from_dir (this_dir
, this_dir_len
))
1104 do_cleanups (cleanups
);
1105 if (libthread_db_debug
)
1106 fprintf_unfiltered (gdb_stdlog
,
1107 _("thread_db_load_search returning %d\n"), rc
);
1111 /* Return non-zero if the inferior has a libpthread. */
1114 has_libpthread (void)
1116 struct objfile
*obj
;
1119 if (libpthread_name_p (objfile_name (obj
)))
1125 /* Attempt to load and initialize libthread_db.
1126 Return 1 on success. */
1129 thread_db_load (void)
1131 struct thread_db_info
*info
;
1133 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1138 /* Don't attempt to use thread_db on executables not running
1140 if (!target_has_registers
)
1143 /* Don't attempt to use thread_db for remote targets. */
1144 if (!(target_can_run (¤t_target
) || core_bfd
))
1147 if (thread_db_load_search ())
1150 /* We couldn't find a libthread_db.
1151 If the inferior has a libpthread warn the user. */
1152 if (has_libpthread ())
1154 warning (_("Unable to find libthread_db matching inferior's thread"
1155 " library, thread debugging will not be available."));
1159 /* Either this executable isn't using libpthread at all, or it is
1160 statically linked. Since we can't easily distinguish these two cases,
1161 no warning is issued. */
1166 disable_thread_event_reporting (struct thread_db_info
*info
)
1168 if (info
->td_ta_clear_event_p
!= NULL
)
1170 td_thr_events_t events
;
1172 /* Set the process wide mask saying we aren't interested in any
1174 td_event_fillset (&events
);
1175 info
->td_ta_clear_event_p (info
->thread_agent
, &events
);
1178 info
->td_create_bp_addr
= 0;
1179 info
->td_death_bp_addr
= 0;
1183 check_thread_signals (void)
1185 if (!thread_signals
)
1190 lin_thread_get_thread_signals (&mask
);
1191 sigemptyset (&thread_stop_set
);
1192 sigemptyset (&thread_print_set
);
1194 for (i
= 1; i
< NSIG
; i
++)
1196 if (sigismember (&mask
, i
))
1198 if (signal_stop_update (gdb_signal_from_host (i
), 0))
1199 sigaddset (&thread_stop_set
, i
);
1200 if (signal_print_update (gdb_signal_from_host (i
), 0))
1201 sigaddset (&thread_print_set
, i
);
1208 /* Check whether thread_db is usable. This function is called when
1209 an inferior is created (or otherwise acquired, e.g. attached to)
1210 and when new shared libraries are loaded into a running process. */
1213 check_for_thread_db (void)
1215 /* Do nothing if we couldn't load libthread_db.so.1. */
1216 if (!thread_db_load ())
1220 /* This function is called via the new_objfile observer. */
1223 thread_db_new_objfile (struct objfile
*objfile
)
1225 /* This observer must always be called with inferior_ptid set
1229 /* libpthread with separate debug info has its debug info file already
1230 loaded (and notified without successful thread_db initialization)
1231 the time observer_notify_new_objfile is called for the library itself.
1232 Static executables have their separate debug info loaded already
1233 before the inferior has started. */
1234 && objfile
->separate_debug_objfile_backlink
== NULL
1235 /* Only check for thread_db if we loaded libpthread,
1236 or if this is the main symbol file.
1237 We need to check OBJF_MAINLINE to handle the case of debugging
1238 a statically linked executable AND the symbol file is specified AFTER
1239 the exec file is loaded (e.g., gdb -c core ; file foo).
1240 For dynamically linked executables, libpthread can be near the end
1241 of the list of shared libraries to load, and in an app of several
1242 thousand shared libraries, this can otherwise be painful. */
1243 && ((objfile
->flags
& OBJF_MAINLINE
) != 0
1244 || libpthread_name_p (objfile_name (objfile
))))
1245 check_for_thread_db ();
1249 check_pid_namespace_match (void)
1251 /* Check is only relevant for local targets targets. */
1252 if (target_can_run (¤t_target
))
1254 /* If the child is in a different PID namespace, its idea of its
1255 PID will differ from our idea of its PID. When we scan the
1256 child's thread list, we'll mistakenly think it has no threads
1257 since the thread PID fields won't match the PID we give to
1259 char *our_pid_ns
= linux_proc_pid_get_ns (getpid (), "pid");
1260 char *inferior_pid_ns
= linux_proc_pid_get_ns (
1261 ptid_get_pid (inferior_ptid
), "pid");
1263 if (our_pid_ns
!= NULL
&& inferior_pid_ns
!= NULL
1264 && strcmp (our_pid_ns
, inferior_pid_ns
) != 0)
1266 warning (_ ("Target and debugger are in different PID "
1267 "namespaces; thread lists and other data are "
1268 "likely unreliable"));
1272 xfree (inferior_pid_ns
);
1276 /* This function is called via the inferior_created observer.
1277 This handles the case of debugging statically linked executables. */
1280 thread_db_inferior_created (struct target_ops
*target
, int from_tty
)
1282 check_pid_namespace_match ();
1283 check_for_thread_db ();
1286 /* Update the thread's state (what's displayed in "info threads"),
1287 from libthread_db thread state information. */
1290 update_thread_state (struct private_thread_info
*private,
1291 const td_thrinfo_t
*ti_p
)
1293 private->dying
= (ti_p
->ti_state
== TD_THR_UNKNOWN
1294 || ti_p
->ti_state
== TD_THR_ZOMBIE
);
1297 /* Attach to a new thread. This function is called when we receive a
1298 TD_CREATE event or when we iterate over all threads and find one
1299 that wasn't already in our list. Returns true on success. */
1302 attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
1303 const td_thrinfo_t
*ti_p
)
1305 struct private_thread_info
*private;
1306 struct thread_info
*tp
;
1308 struct thread_db_info
*info
;
1310 /* If we're being called after a TD_CREATE event, we may already
1311 know about this thread. There are two ways this can happen. We
1312 may have iterated over all threads between the thread creation
1313 and the TD_CREATE event, for instance when the user has issued
1314 the `info threads' command before the SIGTRAP for hitting the
1315 thread creation breakpoint was reported. Alternatively, the
1316 thread may have exited and a new one been created with the same
1317 thread ID. In the first case we don't need to do anything; in
1318 the second case we should discard information about the dead
1319 thread and attach to the new one. */
1320 tp
= find_thread_ptid (ptid
);
1323 /* If tp->private is NULL, then GDB is already attached to this
1324 thread, but we do not know anything about it. We can learn
1325 about it here. This can only happen if we have some other
1326 way besides libthread_db to notice new threads (i.e.
1327 PTRACE_EVENT_CLONE); assume the same mechanism notices thread
1328 exit, so this can not be a stale thread recreated with the
1330 if (tp
->private != NULL
)
1332 if (!tp
->private->dying
)
1335 delete_thread (ptid
);
1340 if (target_has_execution
)
1341 check_thread_signals ();
1343 /* Under GNU/Linux, we have to attach to each and every thread. */
1344 if (target_has_execution
1349 res
= lin_lwp_attach_lwp (ptid_build (ptid_get_pid (ptid
),
1353 /* Error, stop iterating. */
1358 /* Pretend this thread doesn't exist yet, and keep
1363 /* Otherwise, we sucessfully attached to the thread. */
1366 /* Construct the thread's private data. */
1367 private = xmalloc (sizeof (struct private_thread_info
));
1368 memset (private, 0, sizeof (struct private_thread_info
));
1370 /* A thread ID of zero may mean the thread library has not initialized
1371 yet. But we shouldn't even get here if that's the case. FIXME:
1372 if we change GDB to always have at least one thread in the thread
1373 list this will have to go somewhere else; maybe private == NULL
1374 until the thread_db target claims it. */
1375 gdb_assert (ti_p
->ti_tid
!= 0);
1376 private->th
= *th_p
;
1377 private->tid
= ti_p
->ti_tid
;
1378 update_thread_state (private, ti_p
);
1380 /* Add the thread to GDB's thread list. */
1382 add_thread_with_info (ptid
, private);
1384 tp
->private = private;
1386 info
= get_thread_db_info (ptid_get_pid (ptid
));
1388 /* Enable thread event reporting for this thread, except when
1389 debugging a core file. */
1390 if (target_has_execution
&& thread_db_use_events ())
1392 err
= info
->td_thr_event_enable_p (th_p
, 1);
1394 error (_("Cannot enable thread event reporting for %s: %s"),
1395 target_pid_to_str (ptid
), thread_db_err_str (err
));
1402 detach_thread (ptid_t ptid
)
1404 struct thread_info
*thread_info
;
1406 /* Don't delete the thread now, because it still reports as active
1407 until it has executed a few instructions after the event
1408 breakpoint - if we deleted it now, "info threads" would cause us
1409 to re-attach to it. Just mark it as having had a TD_DEATH
1410 event. This means that we won't delete it from our thread list
1411 until we notice that it's dead (via prune_threads), or until
1412 something re-uses its thread ID. We'll report the thread exit
1413 when the underlying LWP dies. */
1414 thread_info
= find_thread_ptid (ptid
);
1415 gdb_assert (thread_info
!= NULL
&& thread_info
->private != NULL
);
1416 thread_info
->private->dying
= 1;
1420 thread_db_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1422 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1423 struct thread_db_info
*info
;
1425 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1429 if (target_has_execution
&& thread_db_use_events ())
1431 disable_thread_event_reporting (info
);
1433 /* Delete the old thread event breakpoints. Note that
1434 unlike when mourning, we can remove them here because
1435 there's still a live inferior to poke at. In any case,
1436 GDB will not try to insert anything in the inferior when
1437 removing a breakpoint. */
1438 remove_thread_event_breakpoints ();
1441 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1444 target_beneath
->to_detach (target_beneath
, args
, from_tty
);
1446 /* NOTE: From this point on, inferior_ptid is null_ptid. */
1448 /* If there are no more processes using libpthread, detach the
1449 thread_db target ops. */
1450 if (!thread_db_list
)
1451 unpush_target (&thread_db_ops
);
1454 /* Check if PID is currently stopped at the location of a thread event
1455 breakpoint location. If it is, read the event message and act upon
1459 check_event (ptid_t ptid
)
1461 struct regcache
*regcache
= get_thread_regcache (ptid
);
1462 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
1468 struct thread_db_info
*info
;
1470 info
= get_thread_db_info (ptid_get_pid (ptid
));
1472 /* Bail out early if we're not at a thread event breakpoint. */
1473 stop_pc
= regcache_read_pc (regcache
)
1474 - target_decr_pc_after_break (gdbarch
);
1475 if (stop_pc
!= info
->td_create_bp_addr
1476 && stop_pc
!= info
->td_death_bp_addr
)
1479 /* Access an lwp we know is stopped. */
1480 info
->proc_handle
.ptid
= ptid
;
1482 /* If we have only looked at the first thread before libpthread was
1483 initialized, we may not know its thread ID yet. Make sure we do
1484 before we add another thread to the list. */
1485 if (!have_threads (ptid
))
1486 thread_db_find_new_threads_1 (ptid
);
1488 /* If we are at a create breakpoint, we do not know what new lwp
1489 was created and cannot specifically locate the event message for it.
1490 We have to call td_ta_event_getmsg() to get
1491 the latest message. Since we have no way of correlating whether
1492 the event message we get back corresponds to our breakpoint, we must
1493 loop and read all event messages, processing them appropriately.
1494 This guarantees we will process the correct message before continuing
1495 from the breakpoint.
1497 Currently, death events are not enabled. If they are enabled,
1498 the death event can use the td_thr_event_getmsg() interface to
1499 get the message specifically for that lwp and avoid looping
1506 err
= info
->td_ta_event_getmsg_p (info
->thread_agent
, &msg
);
1509 if (err
== TD_NOMSG
)
1512 error (_("Cannot get thread event message: %s"),
1513 thread_db_err_str (err
));
1516 err
= info
->td_thr_get_info_p (msg
.th_p
, &ti
);
1518 error (_("Cannot get thread info: %s"), thread_db_err_str (err
));
1520 ptid
= ptid_build (ptid_get_pid (ptid
), ti
.ti_lid
, 0);
1525 /* Call attach_thread whether or not we already know about a
1526 thread with this thread ID. */
1527 attach_thread (ptid
, msg
.th_p
, &ti
);
1533 if (!in_thread_list (ptid
))
1534 error (_("Spurious thread death event."));
1536 detach_thread (ptid
);
1541 error (_("Spurious thread event."));
1548 thread_db_wait (struct target_ops
*ops
,
1549 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
1552 struct thread_db_info
*info
;
1553 struct target_ops
*beneath
= find_target_beneath (ops
);
1555 ptid
= beneath
->to_wait (beneath
, ptid
, ourstatus
, options
);
1557 if (ourstatus
->kind
== TARGET_WAITKIND_IGNORE
)
1560 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
1561 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
1564 info
= get_thread_db_info (ptid_get_pid (ptid
));
1566 /* If this process isn't using thread_db, we're done. */
1570 if (ourstatus
->kind
== TARGET_WAITKIND_EXECD
)
1572 /* New image, it may or may not end up using thread_db. Assume
1573 not unless we find otherwise. */
1574 delete_thread_db_info (ptid_get_pid (ptid
));
1575 if (!thread_db_list
)
1576 unpush_target (&thread_db_ops
);
1578 /* Thread event breakpoints are deleted by
1579 update_breakpoints_after_exec. */
1584 /* If we do not know about the main thread yet, this would be a good time to
1586 if (ourstatus
->kind
== TARGET_WAITKIND_STOPPED
&& !have_threads (ptid
))
1587 thread_db_find_new_threads_1 (ptid
);
1589 if (ourstatus
->kind
== TARGET_WAITKIND_STOPPED
1590 && ourstatus
->value
.sig
== GDB_SIGNAL_TRAP
)
1591 /* Check for a thread event. */
1594 if (have_threads (ptid
))
1596 /* Fill in the thread's user-level thread id. */
1597 thread_from_lwp (ptid
);
1604 thread_db_mourn_inferior (struct target_ops
*ops
)
1606 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1608 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1610 target_beneath
->to_mourn_inferior (target_beneath
);
1612 /* Delete the old thread event breakpoints. Do this after mourning
1613 the inferior, so that we don't try to uninsert them. */
1614 remove_thread_event_breakpoints ();
1616 /* Detach thread_db target ops. */
1617 if (!thread_db_list
)
1618 unpush_target (ops
);
1621 struct callback_data
1623 struct thread_db_info
*info
;
1628 find_new_threads_callback (const td_thrhandle_t
*th_p
, void *data
)
1633 struct thread_info
*tp
;
1634 struct callback_data
*cb_data
= data
;
1635 struct thread_db_info
*info
= cb_data
->info
;
1637 err
= info
->td_thr_get_info_p (th_p
, &ti
);
1639 error (_("find_new_threads_callback: cannot get thread info: %s"),
1640 thread_db_err_str (err
));
1642 if (ti
.ti_lid
== -1)
1644 /* A thread with kernel thread ID -1 is either a thread that
1645 exited and was joined, or a thread that is being created but
1646 hasn't started yet, and that is reusing the tcb/stack of a
1647 thread that previously exited and was joined. (glibc marks
1648 terminated and joined threads with kernel thread ID -1. See
1650 if (libthread_db_debug
)
1651 fprintf_unfiltered (gdb_stdlog
,
1652 "thread_db: skipping exited and "
1653 "joined thread (0x%lx)\n", ti
.ti_tid
);
1659 /* A thread ID of zero means that this is the main thread, but
1660 glibc has not yet initialized thread-local storage and the
1661 pthread library. We do not know what the thread's TID will
1662 be yet. Just enable event reporting and otherwise ignore
1665 /* In that case, we're not stopped in a fork syscall and don't
1666 need this glibc bug workaround. */
1667 info
->need_stale_parent_threads_check
= 0;
1669 if (target_has_execution
&& thread_db_use_events ())
1671 err
= info
->td_thr_event_enable_p (th_p
, 1);
1673 error (_("Cannot enable thread event reporting for LWP %d: %s"),
1674 (int) ti
.ti_lid
, thread_db_err_str (err
));
1680 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1681 bit expensive, as it needs to open /proc/pid/status, so try to
1682 avoid doing the work if we know we don't have to. */
1683 if (info
->need_stale_parent_threads_check
)
1685 int tgid
= linux_proc_get_tgid (ti
.ti_lid
);
1687 if (tgid
!= -1 && tgid
!= info
->pid
)
1691 ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
1692 tp
= find_thread_ptid (ptid
);
1693 if (tp
== NULL
|| tp
->private == NULL
)
1695 if (attach_thread (ptid
, th_p
, &ti
))
1696 cb_data
->new_threads
+= 1;
1698 /* Problem attaching this thread; perhaps it exited before we
1700 This could mean that the thread list inside glibc itself is in
1701 inconsistent state, and libthread_db could go on looping forever
1702 (observed with glibc-2.3.6). To prevent that, terminate
1703 iteration: thread_db_find_new_threads_2 will retry. */
1706 else if (target_has_execution
&& !thread_db_use_events ())
1708 /* Need to update this if not using the libthread_db events
1709 (particularly, the TD_DEATH event). */
1710 update_thread_state (tp
->private, &ti
);
1716 /* Helper for thread_db_find_new_threads_2.
1717 Returns number of new threads found. */
1720 find_new_threads_once (struct thread_db_info
*info
, int iteration
,
1723 volatile struct gdb_exception except
;
1724 struct callback_data data
;
1725 td_err_e err
= TD_ERR
;
1728 data
.new_threads
= 0;
1730 TRY_CATCH (except
, RETURN_MASK_ERROR
)
1732 /* Iterate over all user-space threads to discover new threads. */
1733 err
= info
->td_ta_thr_iter_p (info
->thread_agent
,
1734 find_new_threads_callback
,
1737 TD_THR_LOWEST_PRIORITY
,
1739 TD_THR_ANY_USER_FLAGS
);
1742 if (libthread_db_debug
)
1744 if (except
.reason
< 0)
1745 exception_fprintf (gdb_stdlog
, except
,
1746 "Warning: find_new_threads_once: ");
1748 fprintf_unfiltered (gdb_stdlog
,
1749 _("Found %d new threads in iteration %d.\n"),
1750 data
.new_threads
, iteration
);
1756 return data
.new_threads
;
1759 /* Search for new threads, accessing memory through stopped thread
1760 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1761 searches in a row do not discover any new threads. */
1764 thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
)
1766 td_err_e err
= TD_OK
;
1767 struct thread_db_info
*info
;
1770 info
= get_thread_db_info (ptid_get_pid (ptid
));
1772 /* Access an lwp we know is stopped. */
1773 info
->proc_handle
.ptid
= ptid
;
1777 /* Require 4 successive iterations which do not find any new threads.
1778 The 4 is a heuristic: there is an inherent race here, and I have
1779 seen that 2 iterations in a row are not always sufficient to
1780 "capture" all threads. */
1781 for (i
= 0, loop
= 0; loop
< 4 && err
== TD_OK
; ++i
, ++loop
)
1782 if (find_new_threads_once (info
, i
, &err
) != 0)
1784 /* Found some new threads. Restart the loop from beginning. */
1789 find_new_threads_once (info
, 0, &err
);
1792 error (_("Cannot find new threads: %s"), thread_db_err_str (err
));
1796 thread_db_find_new_threads_1 (ptid_t ptid
)
1798 thread_db_find_new_threads_2 (ptid
, 0);
1802 update_thread_core (struct lwp_info
*info
, void *closure
)
1804 info
->core
= linux_common_core_of_thread (info
->ptid
);
1809 thread_db_update_thread_list (struct target_ops
*ops
)
1811 struct thread_db_info
*info
;
1812 struct inferior
*inf
;
1818 struct thread_info
*thread
;
1823 info
= get_thread_db_info (inf
->pid
);
1827 thread
= any_live_thread_of_process (inf
->pid
);
1828 if (thread
== NULL
|| thread
->executing
)
1831 thread_db_find_new_threads_1 (thread
->ptid
);
1834 if (target_has_execution
)
1835 iterate_over_lwps (minus_one_ptid
/* iterate over all */,
1836 update_thread_core
, NULL
);
1840 thread_db_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
1842 struct thread_info
*thread_info
= find_thread_ptid (ptid
);
1843 struct target_ops
*beneath
;
1845 if (thread_info
!= NULL
&& thread_info
->private != NULL
)
1847 static char buf
[64];
1850 tid
= thread_info
->private->tid
;
1851 snprintf (buf
, sizeof (buf
), "Thread 0x%lx (LWP %ld)",
1852 tid
, ptid_get_lwp (ptid
));
1857 beneath
= find_target_beneath (ops
);
1858 return beneath
->to_pid_to_str (beneath
, ptid
);
1861 /* Return a string describing the state of the thread specified by
1865 thread_db_extra_thread_info (struct target_ops
*self
,
1866 struct thread_info
*info
)
1868 if (info
->private == NULL
)
1871 if (info
->private->dying
)
1877 /* Get the address of the thread local variable in load module LM which
1878 is stored at OFFSET within the thread local storage for thread PTID. */
1881 thread_db_get_thread_local_address (struct target_ops
*ops
,
1886 struct thread_info
*thread_info
;
1887 struct target_ops
*beneath
;
1889 /* If we have not discovered any threads yet, check now. */
1890 if (!have_threads (ptid
))
1891 thread_db_find_new_threads_1 (ptid
);
1893 /* Find the matching thread. */
1894 thread_info
= find_thread_ptid (ptid
);
1896 if (thread_info
!= NULL
&& thread_info
->private != NULL
)
1900 struct thread_db_info
*info
;
1902 info
= get_thread_db_info (ptid_get_pid (ptid
));
1904 /* Finally, get the address of the variable. */
1907 /* glibc doesn't provide the needed interface. */
1908 if (!info
->td_thr_tls_get_addr_p
)
1909 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR
,
1910 _("No TLS library support"));
1912 /* Note the cast through uintptr_t: this interface only works if
1913 a target address fits in a psaddr_t, which is a host pointer.
1914 So a 32-bit debugger can not access 64-bit TLS through this. */
1915 err
= info
->td_thr_tls_get_addr_p (&thread_info
->private->th
,
1916 (psaddr_t
)(uintptr_t) lm
,
1921 /* If glibc doesn't provide the needed interface throw an error
1922 that LM is zero - normally cases it should not be. */
1923 if (!info
->td_thr_tlsbase_p
)
1924 throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR
,
1925 _("TLS load module not found"));
1927 /* This code path handles the case of -static -pthread executables:
1928 https://sourceware.org/ml/libc-help/2014-03/msg00024.html
1929 For older GNU libc r_debug.r_map is NULL. For GNU libc after
1930 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
1931 The constant number 1 depends on GNU __libc_setup_tls
1932 initialization of l_tls_modid to 1. */
1933 err
= info
->td_thr_tlsbase_p (&thread_info
->private->th
,
1935 address
= (char *) address
+ offset
;
1938 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1939 /* The memory hasn't been allocated, yet. */
1940 if (err
== TD_NOTALLOC
)
1941 /* Now, if libthread_db provided the initialization image's
1942 address, we *could* try to build a non-lvalue value from
1943 the initialization image. */
1944 throw_error (TLS_NOT_ALLOCATED_YET_ERROR
,
1945 _("TLS not allocated yet"));
1948 /* Something else went wrong. */
1950 throw_error (TLS_GENERIC_ERROR
,
1951 (("%s")), thread_db_err_str (err
));
1953 /* Cast assuming host == target. Joy. */
1954 /* Do proper sign extension for the target. */
1955 gdb_assert (exec_bfd
);
1956 return (bfd_get_sign_extend_vma (exec_bfd
) > 0
1957 ? (CORE_ADDR
) (intptr_t) address
1958 : (CORE_ADDR
) (uintptr_t) address
);
1961 beneath
= find_target_beneath (ops
);
1962 return beneath
->to_get_thread_local_address (beneath
, ptid
, lm
, offset
);
1965 /* Callback routine used to find a thread based on the TID part of
1969 thread_db_find_thread_from_tid (struct thread_info
*thread
, void *data
)
1971 long *tid
= (long *) data
;
1973 if (thread
->private->tid
== *tid
)
1979 /* Implement the to_get_ada_task_ptid target method for this target. */
1982 thread_db_get_ada_task_ptid (struct target_ops
*self
, long lwp
, long thread
)
1984 struct thread_info
*thread_info
;
1986 thread_db_find_new_threads_1 (inferior_ptid
);
1987 thread_info
= iterate_over_threads (thread_db_find_thread_from_tid
, &thread
);
1989 gdb_assert (thread_info
!= NULL
);
1991 return (thread_info
->ptid
);
1995 thread_db_resume (struct target_ops
*ops
,
1996 ptid_t ptid
, int step
, enum gdb_signal signo
)
1998 struct target_ops
*beneath
= find_target_beneath (ops
);
1999 struct thread_db_info
*info
;
2001 if (ptid_equal (ptid
, minus_one_ptid
))
2002 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
2004 info
= get_thread_db_info (ptid_get_pid (ptid
));
2006 /* This workaround is only needed for child fork lwps stopped in a
2007 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
2008 workaround can be disabled. */
2010 info
->need_stale_parent_threads_check
= 0;
2012 beneath
->to_resume (beneath
, ptid
, step
, signo
);
2015 /* qsort helper function for info_auto_load_libthread_db, sort the
2016 thread_db_info pointers primarily by their FILENAME and secondarily by their
2017 PID, both in ascending order. */
2020 info_auto_load_libthread_db_compare (const void *ap
, const void *bp
)
2022 struct thread_db_info
*a
= *(struct thread_db_info
**) ap
;
2023 struct thread_db_info
*b
= *(struct thread_db_info
**) bp
;
2026 retval
= strcmp (a
->filename
, b
->filename
);
2030 return (a
->pid
> b
->pid
) - (a
->pid
- b
->pid
);
2033 /* Implement 'info auto-load libthread-db'. */
2036 info_auto_load_libthread_db (char *args
, int from_tty
)
2038 struct ui_out
*uiout
= current_uiout
;
2039 const char *cs
= args
? args
: "";
2040 struct thread_db_info
*info
, **array
;
2041 unsigned info_count
, unique_filenames
;
2042 size_t max_filename_len
, max_pids_len
, pids_len
;
2043 struct cleanup
*back_to
;
2047 cs
= skip_spaces_const (cs
);
2049 error (_("'info auto-load libthread-db' does not accept any parameters"));
2052 for (info
= thread_db_list
; info
; info
= info
->next
)
2053 if (info
->filename
!= NULL
)
2056 array
= xmalloc (sizeof (*array
) * info_count
);
2057 back_to
= make_cleanup (xfree
, array
);
2060 for (info
= thread_db_list
; info
; info
= info
->next
)
2061 if (info
->filename
!= NULL
)
2062 array
[info_count
++] = info
;
2064 /* Sort ARRAY by filenames and PIDs. */
2066 qsort (array
, info_count
, sizeof (*array
),
2067 info_auto_load_libthread_db_compare
);
2069 /* Calculate the number of unique filenames (rows) and the maximum string
2070 length of PIDs list for the unique filenames (columns). */
2072 unique_filenames
= 0;
2073 max_filename_len
= 0;
2076 for (i
= 0; i
< info_count
; i
++)
2078 int pid
= array
[i
]->pid
;
2079 size_t this_pid_len
;
2081 for (this_pid_len
= 0; pid
!= 0; pid
/= 10)
2084 if (i
== 0 || strcmp (array
[i
- 1]->filename
, array
[i
]->filename
) != 0)
2087 max_filename_len
= max (max_filename_len
,
2088 strlen (array
[i
]->filename
));
2092 pids_len
-= strlen (", ");
2093 max_pids_len
= max (max_pids_len
, pids_len
);
2097 pids_len
+= this_pid_len
+ strlen (", ");
2101 pids_len
-= strlen (", ");
2102 max_pids_len
= max (max_pids_len
, pids_len
);
2105 /* Table header shifted right by preceding "libthread-db: " would not match
2107 if (info_count
> 0 && args
== auto_load_info_scripts_pattern_nl
)
2108 ui_out_text (uiout
, "\n");
2110 make_cleanup_ui_out_table_begin_end (uiout
, 2, unique_filenames
,
2111 "LinuxThreadDbTable");
2113 ui_out_table_header (uiout
, max_filename_len
, ui_left
, "filename",
2115 ui_out_table_header (uiout
, pids_len
, ui_left
, "PIDs", "Pids");
2116 ui_out_table_body (uiout
);
2118 pids
= xmalloc (max_pids_len
+ 1);
2119 make_cleanup (xfree
, pids
);
2121 /* Note I is incremented inside the cycle, not at its end. */
2122 for (i
= 0; i
< info_count
;)
2124 struct cleanup
*chain
= make_cleanup_ui_out_tuple_begin_end (uiout
, NULL
);
2128 ui_out_field_string (uiout
, "filename", info
->filename
);
2131 while (i
< info_count
&& strcmp (info
->filename
, array
[i
]->filename
) == 0)
2133 if (pids_end
!= pids
)
2138 pids_end
+= xsnprintf (pids_end
, &pids
[max_pids_len
+ 1] - pids_end
,
2139 "%u", array
[i
]->pid
);
2140 gdb_assert (pids_end
< &pids
[max_pids_len
+ 1]);
2146 ui_out_field_string (uiout
, "pids", pids
);
2148 ui_out_text (uiout
, "\n");
2149 do_cleanups (chain
);
2152 do_cleanups (back_to
);
2154 if (info_count
== 0)
2155 ui_out_message (uiout
, 0, _("No auto-loaded libthread-db.\n"));
2159 init_thread_db_ops (void)
2161 thread_db_ops
.to_shortname
= "multi-thread";
2162 thread_db_ops
.to_longname
= "multi-threaded child process.";
2163 thread_db_ops
.to_doc
= "Threads and pthreads support.";
2164 thread_db_ops
.to_detach
= thread_db_detach
;
2165 thread_db_ops
.to_wait
= thread_db_wait
;
2166 thread_db_ops
.to_resume
= thread_db_resume
;
2167 thread_db_ops
.to_mourn_inferior
= thread_db_mourn_inferior
;
2168 thread_db_ops
.to_update_thread_list
= thread_db_update_thread_list
;
2169 thread_db_ops
.to_pid_to_str
= thread_db_pid_to_str
;
2170 thread_db_ops
.to_stratum
= thread_stratum
;
2171 thread_db_ops
.to_has_thread_control
= tc_schedlock
;
2172 thread_db_ops
.to_get_thread_local_address
2173 = thread_db_get_thread_local_address
;
2174 thread_db_ops
.to_extra_thread_info
= thread_db_extra_thread_info
;
2175 thread_db_ops
.to_get_ada_task_ptid
= thread_db_get_ada_task_ptid
;
2176 thread_db_ops
.to_magic
= OPS_MAGIC
;
2178 complete_target_initialization (&thread_db_ops
);
2181 /* Provide a prototype to silence -Wmissing-prototypes. */
2182 extern initialize_file_ftype _initialize_thread_db
;
2185 _initialize_thread_db (void)
2187 init_thread_db_ops ();
2189 /* Defer loading of libthread_db.so until inferior is running.
2190 This allows gdb to load correct libthread_db for a given
2191 executable -- there could be mutiple versions of glibc,
2192 compiled with LinuxThreads or NPTL, and until there is
2193 a running inferior, we can't tell which libthread_db is
2194 the correct one to load. */
2196 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
2198 add_setshow_optional_filename_cmd ("libthread-db-search-path",
2200 &libthread_db_search_path
, _("\
2201 Set search path for libthread_db."), _("\
2202 Show the current search path or libthread_db."), _("\
2203 This path is used to search for libthread_db to be loaded into \
2205 Its value is a colon (':') separate list of directories to search.\n\
2206 Setting the search path to an empty list resets it to its default value."),
2207 set_libthread_db_search_path
,
2209 &setlist
, &showlist
);
2211 add_setshow_zuinteger_cmd ("libthread-db", class_maintenance
,
2212 &libthread_db_debug
, _("\
2213 Set libthread-db debugging."), _("\
2214 Show libthread-db debugging."), _("\
2215 When non-zero, libthread-db debugging is enabled."),
2217 show_libthread_db_debug
,
2218 &setdebuglist
, &showdebuglist
);
2220 add_setshow_boolean_cmd ("libthread-db", class_support
,
2221 &auto_load_thread_db
, _("\
2222 Enable or disable auto-loading of inferior specific libthread_db."), _("\
2223 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
2224 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
2225 locations to load libthread_db compatible with the inferior.\n\
2226 Standard system libthread_db still gets loaded even with this option off.\n\
2227 This options has security implications for untrusted inferiors."),
2228 NULL
, show_auto_load_thread_db
,
2229 auto_load_set_cmdlist_get (),
2230 auto_load_show_cmdlist_get ());
2232 add_cmd ("libthread-db", class_info
, info_auto_load_libthread_db
,
2233 _("Print the list of loaded inferior specific libthread_db.\n\
2234 Usage: info auto-load libthread-db"),
2235 auto_load_info_cmdlist_get ());
2237 /* Add ourselves to objfile event chain. */
2238 observer_attach_new_objfile (thread_db_new_objfile
);
2240 /* Add ourselves to inferior_created event chain.
2241 This is needed to handle debugging statically linked programs where
2242 the new_objfile observer won't get called for libpthread. */
2243 observer_attach_inferior_created (thread_db_inferior_created
);