1 /* libthread_db assisted debugging support, generic parts.
3 Copyright (C) 1999-2014 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-osdata.h"
42 #include "auto-load.h"
43 #include "cli/cli-utils.h"
48 /* GNU/Linux libthread_db support.
50 libthread_db is a library, provided along with libpthread.so, which
51 exposes the internals of the thread library to a debugger. It
52 allows GDB to find existing threads, new threads as they are
53 created, thread IDs (usually, the result of pthread_self), and
54 thread-local variables.
56 The libthread_db interface originates on Solaris, where it is
57 both more powerful and more complicated. This implementation
58 only works for LinuxThreads and NPTL, the two glibc threading
59 libraries. It assumes that each thread is permanently assigned
60 to a single light-weight process (LWP).
62 libthread_db-specific information is stored in the "private" field
63 of struct thread_info. When the field is NULL we do not yet have
64 information about the new thread; this could be temporary (created,
65 but the thread library's data structures do not reflect it yet)
66 or permanent (created using clone instead of pthread_create).
68 Process IDs managed by linux-thread-db.c match those used by
69 linux-nat.c: a common PID for all processes, an LWP ID for each
70 thread, and no TID. We save the TID in private. Keeping it out
71 of the ptid_t prevents thread IDs changing when libpthread is
72 loaded or unloaded. */
74 static char *libthread_db_search_path
;
76 /* Set to non-zero if thread_db auto-loading is enabled
77 by the "set auto-load libthread-db" command. */
78 static int auto_load_thread_db
= 1;
80 /* "show" command for the auto_load_thread_db configuration variable. */
83 show_auto_load_thread_db (struct ui_file
*file
, int from_tty
,
84 struct cmd_list_element
*c
, const char *value
)
86 fprintf_filtered (file
, _("Auto-loading of inferior specific libthread_db "
92 set_libthread_db_search_path (char *ignored
, int from_tty
,
93 struct cmd_list_element
*c
)
95 if (*libthread_db_search_path
== '\0')
97 xfree (libthread_db_search_path
);
98 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
102 /* If non-zero, print details of libthread_db processing. */
104 static unsigned int libthread_db_debug
;
107 show_libthread_db_debug (struct ui_file
*file
, int from_tty
,
108 struct cmd_list_element
*c
, const char *value
)
110 fprintf_filtered (file
, _("libthread-db debugging is %s.\n"), value
);
113 /* If we're running on GNU/Linux, we must explicitly attach to any new
116 /* This module's target vector. */
117 static struct target_ops thread_db_ops
;
119 /* Non-zero if we have determined the signals used by the threads
121 static int thread_signals
;
122 static sigset_t thread_stop_set
;
123 static sigset_t thread_print_set
;
125 struct thread_db_info
127 struct thread_db_info
*next
;
129 /* Process id this object refers to. */
132 /* Handle from dlopen for libthread_db.so. */
135 /* Absolute pathname from gdb_realpath to disk file used for dlopen-ing
136 HANDLE. It may be NULL for system library. */
139 /* Structure that identifies the child process for the
140 <proc_service.h> interface. */
141 struct ps_prochandle proc_handle
;
143 /* Connection to the libthread_db library. */
144 td_thragent_t
*thread_agent
;
146 /* True if we need to apply the workaround for glibc/BZ5983. When
147 we catch a PTRACE_O_TRACEFORK, and go query the child's thread
148 list, nptl_db returns the parent's threads in addition to the new
149 (single) child thread. If this flag is set, we do extra work to
150 be able to ignore such stale entries. */
151 int need_stale_parent_threads_check
;
153 /* Location of the thread creation event breakpoint. The code at
154 this location in the child process will be called by the pthread
155 library whenever a new thread is created. By setting a special
156 breakpoint at this location, GDB can detect when a new thread is
157 created. We obtain this location via the td_ta_event_addr
159 CORE_ADDR td_create_bp_addr
;
161 /* Location of the thread death event breakpoint. */
162 CORE_ADDR td_death_bp_addr
;
164 /* Pointers to the libthread_db functions. */
166 td_err_e (*td_init_p
) (void);
168 td_err_e (*td_ta_new_p
) (struct ps_prochandle
* ps
,
170 td_err_e (*td_ta_map_id2thr_p
) (const td_thragent_t
*ta
, thread_t pt
,
171 td_thrhandle_t
*__th
);
172 td_err_e (*td_ta_map_lwp2thr_p
) (const td_thragent_t
*ta
,
173 lwpid_t lwpid
, td_thrhandle_t
*th
);
174 td_err_e (*td_ta_thr_iter_p
) (const td_thragent_t
*ta
,
175 td_thr_iter_f
*callback
, void *cbdata_p
,
176 td_thr_state_e state
, int ti_pri
,
177 sigset_t
*ti_sigmask_p
,
178 unsigned int ti_user_flags
);
179 td_err_e (*td_ta_event_addr_p
) (const td_thragent_t
*ta
,
180 td_event_e event
, td_notify_t
*ptr
);
181 td_err_e (*td_ta_set_event_p
) (const td_thragent_t
*ta
,
182 td_thr_events_t
*event
);
183 td_err_e (*td_ta_clear_event_p
) (const td_thragent_t
*ta
,
184 td_thr_events_t
*event
);
185 td_err_e (*td_ta_event_getmsg_p
) (const td_thragent_t
*ta
,
186 td_event_msg_t
*msg
);
188 td_err_e (*td_thr_validate_p
) (const td_thrhandle_t
*th
);
189 td_err_e (*td_thr_get_info_p
) (const td_thrhandle_t
*th
,
190 td_thrinfo_t
*infop
);
191 td_err_e (*td_thr_event_enable_p
) (const td_thrhandle_t
*th
,
194 td_err_e (*td_thr_tls_get_addr_p
) (const td_thrhandle_t
*th
,
195 psaddr_t map_address
,
196 size_t offset
, psaddr_t
*address
);
197 td_err_e (*td_thr_tlsbase_p
) (const td_thrhandle_t
*th
,
198 unsigned long int modid
,
202 /* List of known processes using thread_db, and the required
204 struct thread_db_info
*thread_db_list
;
206 static void thread_db_find_new_threads_1 (ptid_t ptid
);
207 static void thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
);
209 /* Add the current inferior to the list of processes using libpthread.
210 Return a pointer to the newly allocated object that was added to
211 THREAD_DB_LIST. HANDLE is the handle returned by dlopen'ing
214 static struct thread_db_info
*
215 add_thread_db_info (void *handle
)
217 struct thread_db_info
*info
;
219 info
= xcalloc (1, sizeof (*info
));
220 info
->pid
= ptid_get_pid (inferior_ptid
);
221 info
->handle
= handle
;
223 /* The workaround works by reading from /proc/pid/status, so it is
224 disabled for core files. */
225 if (target_has_execution
)
226 info
->need_stale_parent_threads_check
= 1;
228 info
->next
= thread_db_list
;
229 thread_db_list
= info
;
234 /* Return the thread_db_info object representing the bookkeeping
235 related to process PID, if any; NULL otherwise. */
237 static struct thread_db_info
*
238 get_thread_db_info (int pid
)
240 struct thread_db_info
*info
;
242 for (info
= thread_db_list
; info
; info
= info
->next
)
243 if (pid
== info
->pid
)
249 /* When PID has exited or has been detached, we no longer want to keep
250 track of it as using libpthread. Call this function to discard
251 thread_db related info related to PID. Note that this closes
252 LIBTHREAD_DB_SO's dlopen'ed handle. */
255 delete_thread_db_info (int pid
)
257 struct thread_db_info
*info
, *info_prev
;
261 for (info
= thread_db_list
; info
; info_prev
= info
, info
= info
->next
)
262 if (pid
== info
->pid
)
268 if (info
->handle
!= NULL
)
269 dlclose (info
->handle
);
271 xfree (info
->filename
);
274 info_prev
->next
= info
->next
;
276 thread_db_list
= info
->next
;
281 /* Prototypes for local functions. */
282 static int attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
283 const td_thrinfo_t
*ti_p
);
284 static void detach_thread (ptid_t ptid
);
287 /* Use "struct private_thread_info" to cache thread state. This is
288 a substantial optimization. */
290 struct private_thread_info
292 /* Flag set when we see a TD_DEATH event for this thread. */
293 unsigned int dying
:1;
295 /* Cached thread state. */
302 thread_db_err_str (td_err_e err
)
309 return "generic 'call succeeded'";
311 return "generic error";
313 return "no thread to satisfy query";
315 return "no sync handle to satisfy query";
317 return "no LWP to satisfy query";
319 return "invalid process handle";
321 return "invalid thread handle";
323 return "invalid synchronization handle";
325 return "invalid thread agent";
327 return "invalid key";
329 return "no event message for getmsg";
331 return "FPU register set not available";
333 return "application not linked with libthread";
335 return "requested event is not supported";
337 return "capability not available";
339 return "debugger service failed";
341 return "operation not applicable to";
343 return "no thread-specific data for this thread";
345 return "malloc failed";
347 return "only part of register set was written/read";
349 return "X register set not available for this thread";
350 #ifdef THREAD_DB_HAS_TD_NOTALLOC
352 return "thread has not yet allocated TLS for given module";
354 #ifdef THREAD_DB_HAS_TD_VERSION
356 return "versions of libpthread and libthread_db do not match";
358 #ifdef THREAD_DB_HAS_TD_NOTLS
360 return "there is no TLS segment in the given module";
363 snprintf (buf
, sizeof (buf
), "unknown thread_db error '%d'", err
);
368 /* Return 1 if any threads have been registered. There may be none if
369 the threading library is not fully initialized yet. */
372 have_threads_callback (struct thread_info
*thread
, void *args
)
374 int pid
= * (int *) args
;
376 if (ptid_get_pid (thread
->ptid
) != pid
)
379 return thread
->private != NULL
;
383 have_threads (ptid_t ptid
)
385 int pid
= ptid_get_pid (ptid
);
387 return iterate_over_threads (have_threads_callback
, &pid
) != NULL
;
390 struct thread_get_info_inout
392 struct thread_info
*thread_info
;
393 struct thread_db_info
*thread_db_info
;
396 /* A callback function for td_ta_thr_iter, which we use to map all
399 THP is a handle to the current thread; if INFOP is not NULL, the
400 struct thread_info associated with this thread is returned in
403 If the thread is a zombie, TD_THR_ZOMBIE is returned. Otherwise,
404 zero is returned to indicate success. */
407 thread_get_info_callback (const td_thrhandle_t
*thp
, void *argp
)
412 struct thread_get_info_inout
*inout
;
413 struct thread_db_info
*info
;
416 info
= inout
->thread_db_info
;
418 err
= info
->td_thr_get_info_p (thp
, &ti
);
420 error (_("thread_get_info_callback: cannot get thread info: %s"),
421 thread_db_err_str (err
));
423 /* Fill the cache. */
424 thread_ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
425 inout
->thread_info
= find_thread_ptid (thread_ptid
);
427 if (inout
->thread_info
== NULL
)
429 /* New thread. Attach to it now (why wait?). */
430 if (!have_threads (thread_ptid
))
431 thread_db_find_new_threads_1 (thread_ptid
);
433 attach_thread (thread_ptid
, thp
, &ti
);
434 inout
->thread_info
= find_thread_ptid (thread_ptid
);
435 gdb_assert (inout
->thread_info
!= NULL
);
441 /* Fetch the user-level thread id of PTID. */
444 thread_from_lwp (ptid_t ptid
)
448 struct thread_db_info
*info
;
449 struct thread_get_info_inout io
= {0};
451 /* Just in case td_ta_map_lwp2thr doesn't initialize it completely. */
454 /* This ptid comes from linux-nat.c, which should always fill in the
456 gdb_assert (ptid_get_lwp (ptid
) != 0);
458 info
= get_thread_db_info (ptid_get_pid (ptid
));
460 /* Access an lwp we know is stopped. */
461 info
->proc_handle
.ptid
= ptid
;
462 err
= info
->td_ta_map_lwp2thr_p (info
->thread_agent
, ptid_get_lwp (ptid
),
465 error (_("Cannot find user-level thread for LWP %ld: %s"),
466 ptid_get_lwp (ptid
), thread_db_err_str (err
));
468 /* Long-winded way of fetching the thread info. */
469 io
.thread_db_info
= info
;
470 io
.thread_info
= NULL
;
471 thread_get_info_callback (&th
, &io
);
475 /* Attach to lwp PTID, doing whatever else is required to have this
476 LWP under the debugger's control --- e.g., enabling event
477 reporting. Returns true on success. */
479 thread_db_attach_lwp (ptid_t ptid
)
484 struct thread_db_info
*info
;
486 info
= get_thread_db_info (ptid_get_pid (ptid
));
491 /* This ptid comes from linux-nat.c, which should always fill in the
493 gdb_assert (ptid_get_lwp (ptid
) != 0);
495 /* Access an lwp we know is stopped. */
496 info
->proc_handle
.ptid
= ptid
;
498 /* If we have only looked at the first thread before libpthread was
499 initialized, we may not know its thread ID yet. Make sure we do
500 before we add another thread to the list. */
501 if (!have_threads (ptid
))
502 thread_db_find_new_threads_1 (ptid
);
504 err
= info
->td_ta_map_lwp2thr_p (info
->thread_agent
, ptid_get_lwp (ptid
),
507 /* Cannot find user-level thread. */
510 err
= info
->td_thr_get_info_p (&th
, &ti
);
513 warning (_("Cannot get thread info: %s"), thread_db_err_str (err
));
517 attach_thread (ptid
, &th
, &ti
);
522 verbose_dlsym (void *handle
, const char *name
)
524 void *sym
= dlsym (handle
, name
);
526 warning (_("Symbol \"%s\" not found in libthread_db: %s"),
532 enable_thread_event (int event
, CORE_ADDR
*bp
)
536 struct thread_db_info
*info
;
538 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
540 /* Access an lwp we know is stopped. */
541 info
->proc_handle
.ptid
= inferior_ptid
;
543 /* Get the breakpoint address for thread EVENT. */
544 err
= info
->td_ta_event_addr_p (info
->thread_agent
, event
, ¬ify
);
548 /* Set up the breakpoint. */
549 gdb_assert (exec_bfd
);
550 (*bp
) = (gdbarch_convert_from_func_ptr_addr
552 /* Do proper sign extension for the target. */
553 (bfd_get_sign_extend_vma (exec_bfd
) > 0
554 ? (CORE_ADDR
) (intptr_t) notify
.u
.bptaddr
555 : (CORE_ADDR
) (uintptr_t) notify
.u
.bptaddr
),
557 create_thread_event_breakpoint (target_gdbarch (), *bp
);
562 /* Verify inferior's '\0'-terminated symbol VER_SYMBOL starts with "%d.%d" and
563 return 1 if this version is lower (and not equal) to
564 VER_MAJOR_MIN.VER_MINOR_MIN. Return 0 in all other cases. */
567 inferior_has_bug (const char *ver_symbol
, int ver_major_min
, int ver_minor_min
)
569 struct bound_minimal_symbol version_msym
;
570 CORE_ADDR version_addr
;
572 int err
, got
, retval
= 0;
574 version_msym
= lookup_minimal_symbol (ver_symbol
, NULL
, NULL
);
575 if (version_msym
.minsym
== NULL
)
578 version_addr
= BMSYMBOL_VALUE_ADDRESS (version_msym
);
579 got
= target_read_string (version_addr
, &version
, 32, &err
);
580 if (err
== 0 && memchr (version
, 0, got
) == &version
[got
-1])
584 retval
= (sscanf (version
, "%d.%d", &major
, &minor
) == 2
585 && (major
< ver_major_min
586 || (major
== ver_major_min
&& minor
< ver_minor_min
)));
594 enable_thread_event_reporting (void)
596 td_thr_events_t events
;
598 struct thread_db_info
*info
;
600 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
602 /* We cannot use the thread event reporting facility if these
603 functions aren't available. */
604 if (info
->td_ta_event_addr_p
== NULL
605 || info
->td_ta_set_event_p
== NULL
606 || info
->td_ta_event_getmsg_p
== NULL
607 || info
->td_thr_event_enable_p
== NULL
)
610 /* Set the process wide mask saying which events we're interested in. */
611 td_event_emptyset (&events
);
612 td_event_addset (&events
, TD_CREATE
);
614 /* There is a bug fixed between linuxthreads 2.1.3 and 2.2 by
615 commit 2e4581e4fba917f1779cd0a010a45698586c190a
616 * manager.c (pthread_exited): Correctly report event as TD_REAP
617 instead of TD_DEATH. Fix comments.
618 where event reporting facility is broken for TD_DEATH events,
619 so don't enable it if we have glibc but a lower version. */
620 if (!inferior_has_bug ("__linuxthreads_version", 2, 2))
621 td_event_addset (&events
, TD_DEATH
);
623 err
= info
->td_ta_set_event_p (info
->thread_agent
, &events
);
626 warning (_("Unable to set global thread event mask: %s"),
627 thread_db_err_str (err
));
631 /* Delete previous thread event breakpoints, if any. */
632 remove_thread_event_breakpoints ();
633 info
->td_create_bp_addr
= 0;
634 info
->td_death_bp_addr
= 0;
636 /* Set up the thread creation event. */
637 err
= enable_thread_event (TD_CREATE
, &info
->td_create_bp_addr
);
640 warning (_("Unable to get location for thread creation breakpoint: %s"),
641 thread_db_err_str (err
));
645 /* Set up the thread death event. */
646 err
= enable_thread_event (TD_DEATH
, &info
->td_death_bp_addr
);
649 warning (_("Unable to get location for thread death breakpoint: %s"),
650 thread_db_err_str (err
));
655 /* Similar as thread_db_find_new_threads_1, but try to silently ignore errors
658 Return 1 if the caller should abort libthread_db initialization. Return 0
662 thread_db_find_new_threads_silently (ptid_t ptid
)
664 volatile struct gdb_exception except
;
666 TRY_CATCH (except
, RETURN_MASK_ERROR
)
668 thread_db_find_new_threads_2 (ptid
, 1);
671 if (except
.reason
< 0)
673 if (libthread_db_debug
)
674 exception_fprintf (gdb_stderr
, except
,
675 "Warning: thread_db_find_new_threads_silently: ");
677 /* There is a bug fixed between nptl 2.6.1 and 2.7 by
678 commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
679 where calls to td_thr_get_info fail with TD_ERR for statically linked
680 executables if td_thr_get_info is called before glibc has initialized
683 If the nptl bug is NOT present in the inferior and still thread_db
684 reports an error return 1. It means the inferior has corrupted thread
685 list and GDB should fall back only to LWPs.
687 If the nptl bug is present in the inferior return 0 to silently ignore
688 such errors, and let gdb enumerate threads again later. In such case
689 GDB cannot properly display LWPs if the inferior thread list is
690 corrupted. For core files it does not apply, no 'later enumeration'
693 if (!target_has_execution
|| !inferior_has_bug ("nptl_version", 2, 7))
695 exception_fprintf (gdb_stderr
, except
,
696 _("Warning: couldn't activate thread debugging "
697 "using libthread_db: "));
704 /* Lookup a library in which given symbol resides.
705 Note: this is looking in GDB process, not in the inferior.
706 Returns library name, or NULL. */
709 dladdr_to_soname (const void *addr
)
713 if (dladdr (addr
, &info
) != 0)
714 return info
.dli_fname
;
718 /* Attempt to initialize dlopen()ed libthread_db, described by INFO.
720 Failure could happen if libthread_db does not have symbols we expect,
721 or when it refuses to work with the current inferior (e.g. due to
722 version mismatch between libthread_db and libpthread). */
725 try_thread_db_load_1 (struct thread_db_info
*info
)
729 /* Initialize pointers to the dynamic library functions we will use.
730 Essential functions first. */
732 info
->td_init_p
= verbose_dlsym (info
->handle
, "td_init");
733 if (info
->td_init_p
== NULL
)
736 err
= info
->td_init_p ();
739 warning (_("Cannot initialize libthread_db: %s"),
740 thread_db_err_str (err
));
744 info
->td_ta_new_p
= verbose_dlsym (info
->handle
, "td_ta_new");
745 if (info
->td_ta_new_p
== NULL
)
748 /* Initialize the structure that identifies the child process. */
749 info
->proc_handle
.ptid
= inferior_ptid
;
751 /* Now attempt to open a connection to the thread library. */
752 err
= info
->td_ta_new_p (&info
->proc_handle
, &info
->thread_agent
);
755 if (libthread_db_debug
)
756 printf_unfiltered (_("td_ta_new failed: %s\n"),
757 thread_db_err_str (err
));
762 #ifdef THREAD_DB_HAS_TD_VERSION
765 /* The errors above are not unexpected and silently ignored:
766 they just mean we haven't found correct version of
770 warning (_("td_ta_new failed: %s"), thread_db_err_str (err
));
775 info
->td_ta_map_id2thr_p
= verbose_dlsym (info
->handle
, "td_ta_map_id2thr");
776 if (info
->td_ta_map_id2thr_p
== NULL
)
779 info
->td_ta_map_lwp2thr_p
= verbose_dlsym (info
->handle
,
780 "td_ta_map_lwp2thr");
781 if (info
->td_ta_map_lwp2thr_p
== NULL
)
784 info
->td_ta_thr_iter_p
= verbose_dlsym (info
->handle
, "td_ta_thr_iter");
785 if (info
->td_ta_thr_iter_p
== NULL
)
788 info
->td_thr_validate_p
= verbose_dlsym (info
->handle
, "td_thr_validate");
789 if (info
->td_thr_validate_p
== NULL
)
792 info
->td_thr_get_info_p
= verbose_dlsym (info
->handle
, "td_thr_get_info");
793 if (info
->td_thr_get_info_p
== NULL
)
796 /* These are not essential. */
797 info
->td_ta_event_addr_p
= dlsym (info
->handle
, "td_ta_event_addr");
798 info
->td_ta_set_event_p
= dlsym (info
->handle
, "td_ta_set_event");
799 info
->td_ta_clear_event_p
= dlsym (info
->handle
, "td_ta_clear_event");
800 info
->td_ta_event_getmsg_p
= dlsym (info
->handle
, "td_ta_event_getmsg");
801 info
->td_thr_event_enable_p
= dlsym (info
->handle
, "td_thr_event_enable");
802 info
->td_thr_tls_get_addr_p
= dlsym (info
->handle
, "td_thr_tls_get_addr");
803 info
->td_thr_tlsbase_p
= dlsym (info
->handle
, "td_thr_tlsbase");
805 if (thread_db_find_new_threads_silently (inferior_ptid
) != 0)
807 /* Even if libthread_db initializes, if the thread list is
808 corrupted, we'd not manage to list any threads. Better reject this
809 thread_db, and fall back to at least listing LWPs. */
813 printf_unfiltered (_("[Thread debugging using libthread_db enabled]\n"));
815 if (libthread_db_debug
|| *libthread_db_search_path
)
819 library
= dladdr_to_soname (*info
->td_ta_new_p
);
821 library
= LIBTHREAD_DB_SO
;
823 printf_unfiltered (_("Using host libthread_db library \"%s\".\n"),
827 /* The thread library was detected. Activate the thread_db target
828 if this is the first process using it. */
829 if (thread_db_list
->next
== NULL
)
830 push_target (&thread_db_ops
);
832 /* Enable event reporting, but not when debugging a core file. */
833 if (target_has_execution
)
834 enable_thread_event_reporting ();
839 /* Attempt to use LIBRARY as libthread_db. LIBRARY could be absolute,
840 relative, or just LIBTHREAD_DB. */
843 try_thread_db_load (const char *library
, int check_auto_load_safe
)
846 struct thread_db_info
*info
;
848 if (libthread_db_debug
)
849 printf_unfiltered (_("Trying host libthread_db library: %s.\n"),
852 if (check_auto_load_safe
)
854 if (access (library
, R_OK
) != 0)
856 /* Do not print warnings by file_is_auto_load_safe if the library does
857 not exist at this place. */
858 if (libthread_db_debug
)
859 printf_unfiltered (_("open failed: %s.\n"), safe_strerror (errno
));
863 if (!file_is_auto_load_safe (library
, _("auto-load: Loading libthread-db "
864 "library \"%s\" from explicit "
870 handle
= dlopen (library
, RTLD_NOW
);
873 if (libthread_db_debug
)
874 printf_unfiltered (_("dlopen failed: %s.\n"), dlerror ());
878 if (libthread_db_debug
&& strchr (library
, '/') == NULL
)
882 td_init
= dlsym (handle
, "td_init");
885 const char *const libpath
= dladdr_to_soname (td_init
);
888 printf_unfiltered (_("Host %s resolved to: %s.\n"),
893 info
= add_thread_db_info (handle
);
895 /* Do not save system library name, that one is always trusted. */
896 if (strchr (library
, '/') != NULL
)
897 info
->filename
= gdb_realpath (library
);
899 if (try_thread_db_load_1 (info
))
902 /* This library "refused" to work on current inferior. */
903 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
907 /* Subroutine of try_thread_db_load_from_pdir to simplify it.
908 Try loading libthread_db in directory(OBJ)/SUBDIR.
909 SUBDIR may be NULL. It may also be something like "../lib64".
910 The result is true for success. */
913 try_thread_db_load_from_pdir_1 (struct objfile
*obj
, const char *subdir
)
915 struct cleanup
*cleanup
;
918 const char *obj_name
= objfile_name (obj
);
920 if (obj_name
[0] != '/')
922 warning (_("Expected absolute pathname for libpthread in the"
923 " inferior, but got %s."), obj_name
);
927 path
= xmalloc (strlen (obj_name
) + (subdir
? strlen (subdir
) + 1 : 0)
928 + 1 + strlen (LIBTHREAD_DB_SO
) + 1);
929 cleanup
= make_cleanup (xfree
, path
);
931 strcpy (path
, obj_name
);
932 cp
= strrchr (path
, '/');
933 /* This should at minimum hit the first character. */
934 gdb_assert (cp
!= NULL
);
941 strcat (cp
, LIBTHREAD_DB_SO
);
943 result
= try_thread_db_load (path
, 1);
945 do_cleanups (cleanup
);
949 /* Handle $pdir in libthread-db-search-path.
950 Look for libthread_db in directory(libpthread)/SUBDIR.
951 SUBDIR may be NULL. It may also be something like "../lib64".
952 The result is true for success. */
955 try_thread_db_load_from_pdir (const char *subdir
)
959 if (!auto_load_thread_db
)
963 if (libpthread_name_p (objfile_name (obj
)))
965 if (try_thread_db_load_from_pdir_1 (obj
, subdir
))
968 /* We may have found the separate-debug-info version of
969 libpthread, and it may live in a directory without a matching
971 if (obj
->separate_debug_objfile_backlink
!= NULL
)
972 return try_thread_db_load_from_pdir_1 (obj
->separate_debug_objfile_backlink
,
981 /* Handle $sdir in libthread-db-search-path.
982 Look for libthread_db in the system dirs, or wherever a plain
983 dlopen(file_without_path) will look.
984 The result is true for success. */
987 try_thread_db_load_from_sdir (void)
989 return try_thread_db_load (LIBTHREAD_DB_SO
, 0);
992 /* Try to load libthread_db from directory DIR of length DIR_LEN.
993 The result is true for success. */
996 try_thread_db_load_from_dir (const char *dir
, size_t dir_len
)
998 struct cleanup
*cleanup
;
1002 if (!auto_load_thread_db
)
1005 path
= xmalloc (dir_len
+ 1 + strlen (LIBTHREAD_DB_SO
) + 1);
1006 cleanup
= make_cleanup (xfree
, path
);
1008 memcpy (path
, dir
, dir_len
);
1009 path
[dir_len
] = '/';
1010 strcpy (path
+ dir_len
+ 1, LIBTHREAD_DB_SO
);
1012 result
= try_thread_db_load (path
, 1);
1014 do_cleanups (cleanup
);
1018 /* Search libthread_db_search_path for libthread_db which "agrees"
1019 to work on current inferior.
1020 The result is true for success. */
1023 thread_db_load_search (void)
1025 VEC (char_ptr
) *dir_vec
;
1026 struct cleanup
*cleanups
;
1030 dir_vec
= dirnames_to_char_ptr_vec (libthread_db_search_path
);
1031 cleanups
= make_cleanup_free_char_ptr_vec (dir_vec
);
1033 for (i
= 0; VEC_iterate (char_ptr
, dir_vec
, i
, this_dir
); ++i
)
1035 const int pdir_len
= sizeof ("$pdir") - 1;
1036 size_t this_dir_len
;
1038 this_dir_len
= strlen (this_dir
);
1040 if (strncmp (this_dir
, "$pdir", pdir_len
) == 0
1041 && (this_dir
[pdir_len
] == '\0'
1042 || this_dir
[pdir_len
] == '/'))
1044 char *subdir
= NULL
;
1045 struct cleanup
*free_subdir_cleanup
1046 = make_cleanup (null_cleanup
, NULL
);
1048 if (this_dir
[pdir_len
] == '/')
1050 subdir
= xmalloc (strlen (this_dir
));
1051 make_cleanup (xfree
, subdir
);
1052 strcpy (subdir
, this_dir
+ pdir_len
+ 1);
1054 rc
= try_thread_db_load_from_pdir (subdir
);
1055 do_cleanups (free_subdir_cleanup
);
1059 else if (strcmp (this_dir
, "$sdir") == 0)
1061 if (try_thread_db_load_from_sdir ())
1069 if (try_thread_db_load_from_dir (this_dir
, this_dir_len
))
1077 do_cleanups (cleanups
);
1078 if (libthread_db_debug
)
1079 printf_unfiltered (_("thread_db_load_search returning %d\n"), rc
);
1083 /* Return non-zero if the inferior has a libpthread. */
1086 has_libpthread (void)
1088 struct objfile
*obj
;
1091 if (libpthread_name_p (objfile_name (obj
)))
1097 /* Attempt to load and initialize libthread_db.
1098 Return 1 on success. */
1101 thread_db_load (void)
1103 struct thread_db_info
*info
;
1105 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1110 /* Don't attempt to use thread_db on executables not running
1112 if (!target_has_registers
)
1115 /* Don't attempt to use thread_db for remote targets. */
1116 if (!(target_can_run (¤t_target
) || core_bfd
))
1119 if (thread_db_load_search ())
1122 /* We couldn't find a libthread_db.
1123 If the inferior has a libpthread warn the user. */
1124 if (has_libpthread ())
1126 warning (_("Unable to find libthread_db matching inferior's thread"
1127 " library, thread debugging will not be available."));
1131 /* Either this executable isn't using libpthread at all, or it is
1132 statically linked. Since we can't easily distinguish these two cases,
1133 no warning is issued. */
1138 disable_thread_event_reporting (struct thread_db_info
*info
)
1140 if (info
->td_ta_clear_event_p
!= NULL
)
1142 td_thr_events_t events
;
1144 /* Set the process wide mask saying we aren't interested in any
1146 td_event_fillset (&events
);
1147 info
->td_ta_clear_event_p (info
->thread_agent
, &events
);
1150 info
->td_create_bp_addr
= 0;
1151 info
->td_death_bp_addr
= 0;
1155 check_thread_signals (void)
1157 if (!thread_signals
)
1162 lin_thread_get_thread_signals (&mask
);
1163 sigemptyset (&thread_stop_set
);
1164 sigemptyset (&thread_print_set
);
1166 for (i
= 1; i
< NSIG
; i
++)
1168 if (sigismember (&mask
, i
))
1170 if (signal_stop_update (gdb_signal_from_host (i
), 0))
1171 sigaddset (&thread_stop_set
, i
);
1172 if (signal_print_update (gdb_signal_from_host (i
), 0))
1173 sigaddset (&thread_print_set
, i
);
1180 /* Check whether thread_db is usable. This function is called when
1181 an inferior is created (or otherwise acquired, e.g. attached to)
1182 and when new shared libraries are loaded into a running process. */
1185 check_for_thread_db (void)
1187 /* Do nothing if we couldn't load libthread_db.so.1. */
1188 if (!thread_db_load ())
1192 /* This function is called via the new_objfile observer. */
1195 thread_db_new_objfile (struct objfile
*objfile
)
1197 /* This observer must always be called with inferior_ptid set
1201 /* libpthread with separate debug info has its debug info file already
1202 loaded (and notified without successful thread_db initialization)
1203 the time observer_notify_new_objfile is called for the library itself.
1204 Static executables have their separate debug info loaded already
1205 before the inferior has started. */
1206 && objfile
->separate_debug_objfile_backlink
== NULL
1207 /* Only check for thread_db if we loaded libpthread,
1208 or if this is the main symbol file.
1209 We need to check OBJF_MAINLINE to handle the case of debugging
1210 a statically linked executable AND the symbol file is specified AFTER
1211 the exec file is loaded (e.g., gdb -c core ; file foo).
1212 For dynamically linked executables, libpthread can be near the end
1213 of the list of shared libraries to load, and in an app of several
1214 thousand shared libraries, this can otherwise be painful. */
1215 && ((objfile
->flags
& OBJF_MAINLINE
) != 0
1216 || libpthread_name_p (objfile_name (objfile
))))
1217 check_for_thread_db ();
1221 check_pid_namespace_match (void)
1223 /* Check is only relevant for local targets targets. */
1224 if (target_can_run (¤t_target
))
1226 /* If the child is in a different PID namespace, its idea of its
1227 PID will differ from our idea of its PID. When we scan the
1228 child's thread list, we'll mistakenly think it has no threads
1229 since the thread PID fields won't match the PID we give to
1231 char *our_pid_ns
= linux_proc_pid_get_ns (getpid (), "pid");
1232 char *inferior_pid_ns
= linux_proc_pid_get_ns (
1233 ptid_get_pid (inferior_ptid
), "pid");
1235 if (our_pid_ns
!= NULL
&& inferior_pid_ns
!= NULL
1236 && strcmp (our_pid_ns
, inferior_pid_ns
) != 0)
1238 warning (_ ("Target and debugger are in different PID "
1239 "namespaces; thread lists and other data are "
1240 "likely unreliable"));
1244 xfree (inferior_pid_ns
);
1248 /* This function is called via the inferior_created observer.
1249 This handles the case of debugging statically linked executables. */
1252 thread_db_inferior_created (struct target_ops
*target
, int from_tty
)
1254 check_pid_namespace_match ();
1255 check_for_thread_db ();
1258 /* Attach to a new thread. This function is called when we receive a
1259 TD_CREATE event or when we iterate over all threads and find one
1260 that wasn't already in our list. Returns true on success. */
1263 attach_thread (ptid_t ptid
, const td_thrhandle_t
*th_p
,
1264 const td_thrinfo_t
*ti_p
)
1266 struct private_thread_info
*private;
1267 struct thread_info
*tp
;
1269 struct thread_db_info
*info
;
1271 /* If we're being called after a TD_CREATE event, we may already
1272 know about this thread. There are two ways this can happen. We
1273 may have iterated over all threads between the thread creation
1274 and the TD_CREATE event, for instance when the user has issued
1275 the `info threads' command before the SIGTRAP for hitting the
1276 thread creation breakpoint was reported. Alternatively, the
1277 thread may have exited and a new one been created with the same
1278 thread ID. In the first case we don't need to do anything; in
1279 the second case we should discard information about the dead
1280 thread and attach to the new one. */
1281 tp
= find_thread_ptid (ptid
);
1284 /* If tp->private is NULL, then GDB is already attached to this
1285 thread, but we do not know anything about it. We can learn
1286 about it here. This can only happen if we have some other
1287 way besides libthread_db to notice new threads (i.e.
1288 PTRACE_EVENT_CLONE); assume the same mechanism notices thread
1289 exit, so this can not be a stale thread recreated with the
1291 if (tp
->private != NULL
)
1293 if (!tp
->private->dying
)
1296 delete_thread (ptid
);
1301 if (target_has_execution
)
1302 check_thread_signals ();
1304 /* Under GNU/Linux, we have to attach to each and every thread. */
1305 if (target_has_execution
1310 res
= lin_lwp_attach_lwp (ptid_build (ptid_get_pid (ptid
),
1314 /* Error, stop iterating. */
1319 /* Pretend this thread doesn't exist yet, and keep
1324 /* Otherwise, we sucessfully attached to the thread. */
1327 /* Construct the thread's private data. */
1328 private = xmalloc (sizeof (struct private_thread_info
));
1329 memset (private, 0, sizeof (struct private_thread_info
));
1331 /* A thread ID of zero may mean the thread library has not initialized
1332 yet. But we shouldn't even get here if that's the case. FIXME:
1333 if we change GDB to always have at least one thread in the thread
1334 list this will have to go somewhere else; maybe private == NULL
1335 until the thread_db target claims it. */
1336 gdb_assert (ti_p
->ti_tid
!= 0);
1337 private->th
= *th_p
;
1338 private->tid
= ti_p
->ti_tid
;
1339 if (ti_p
->ti_state
== TD_THR_UNKNOWN
|| ti_p
->ti_state
== TD_THR_ZOMBIE
)
1342 /* Add the thread to GDB's thread list. */
1344 add_thread_with_info (ptid
, private);
1346 tp
->private = private;
1348 info
= get_thread_db_info (ptid_get_pid (ptid
));
1350 /* Enable thread event reporting for this thread, except when
1351 debugging a core file. */
1352 if (target_has_execution
)
1354 err
= info
->td_thr_event_enable_p (th_p
, 1);
1356 error (_("Cannot enable thread event reporting for %s: %s"),
1357 target_pid_to_str (ptid
), thread_db_err_str (err
));
1364 detach_thread (ptid_t ptid
)
1366 struct thread_info
*thread_info
;
1368 /* Don't delete the thread now, because it still reports as active
1369 until it has executed a few instructions after the event
1370 breakpoint - if we deleted it now, "info threads" would cause us
1371 to re-attach to it. Just mark it as having had a TD_DEATH
1372 event. This means that we won't delete it from our thread list
1373 until we notice that it's dead (via prune_threads), or until
1374 something re-uses its thread ID. We'll report the thread exit
1375 when the underlying LWP dies. */
1376 thread_info
= find_thread_ptid (ptid
);
1377 gdb_assert (thread_info
!= NULL
&& thread_info
->private != NULL
);
1378 thread_info
->private->dying
= 1;
1382 thread_db_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1384 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1385 struct thread_db_info
*info
;
1387 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1391 if (target_has_execution
)
1393 disable_thread_event_reporting (info
);
1395 /* Delete the old thread event breakpoints. Note that
1396 unlike when mourning, we can remove them here because
1397 there's still a live inferior to poke at. In any case,
1398 GDB will not try to insert anything in the inferior when
1399 removing a breakpoint. */
1400 remove_thread_event_breakpoints ();
1403 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1406 target_beneath
->to_detach (target_beneath
, args
, from_tty
);
1408 /* NOTE: From this point on, inferior_ptid is null_ptid. */
1410 /* If there are no more processes using libpthread, detach the
1411 thread_db target ops. */
1412 if (!thread_db_list
)
1413 unpush_target (&thread_db_ops
);
1416 /* Check if PID is currently stopped at the location of a thread event
1417 breakpoint location. If it is, read the event message and act upon
1421 check_event (ptid_t ptid
)
1423 struct regcache
*regcache
= get_thread_regcache (ptid
);
1424 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
1430 struct thread_db_info
*info
;
1432 info
= get_thread_db_info (ptid_get_pid (ptid
));
1434 /* Bail out early if we're not at a thread event breakpoint. */
1435 stop_pc
= regcache_read_pc (regcache
)
1436 - target_decr_pc_after_break (gdbarch
);
1437 if (stop_pc
!= info
->td_create_bp_addr
1438 && stop_pc
!= info
->td_death_bp_addr
)
1441 /* Access an lwp we know is stopped. */
1442 info
->proc_handle
.ptid
= ptid
;
1444 /* If we have only looked at the first thread before libpthread was
1445 initialized, we may not know its thread ID yet. Make sure we do
1446 before we add another thread to the list. */
1447 if (!have_threads (ptid
))
1448 thread_db_find_new_threads_1 (ptid
);
1450 /* If we are at a create breakpoint, we do not know what new lwp
1451 was created and cannot specifically locate the event message for it.
1452 We have to call td_ta_event_getmsg() to get
1453 the latest message. Since we have no way of correlating whether
1454 the event message we get back corresponds to our breakpoint, we must
1455 loop and read all event messages, processing them appropriately.
1456 This guarantees we will process the correct message before continuing
1457 from the breakpoint.
1459 Currently, death events are not enabled. If they are enabled,
1460 the death event can use the td_thr_event_getmsg() interface to
1461 get the message specifically for that lwp and avoid looping
1468 err
= info
->td_ta_event_getmsg_p (info
->thread_agent
, &msg
);
1471 if (err
== TD_NOMSG
)
1474 error (_("Cannot get thread event message: %s"),
1475 thread_db_err_str (err
));
1478 err
= info
->td_thr_get_info_p (msg
.th_p
, &ti
);
1480 error (_("Cannot get thread info: %s"), thread_db_err_str (err
));
1482 ptid
= ptid_build (ptid_get_pid (ptid
), ti
.ti_lid
, 0);
1487 /* Call attach_thread whether or not we already know about a
1488 thread with this thread ID. */
1489 attach_thread (ptid
, msg
.th_p
, &ti
);
1495 if (!in_thread_list (ptid
))
1496 error (_("Spurious thread death event."));
1498 detach_thread (ptid
);
1503 error (_("Spurious thread event."));
1510 thread_db_wait (struct target_ops
*ops
,
1511 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
1514 struct thread_db_info
*info
;
1515 struct target_ops
*beneath
= find_target_beneath (ops
);
1517 ptid
= beneath
->to_wait (beneath
, ptid
, ourstatus
, options
);
1519 if (ourstatus
->kind
== TARGET_WAITKIND_IGNORE
)
1522 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
1523 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
1526 info
= get_thread_db_info (ptid_get_pid (ptid
));
1528 /* If this process isn't using thread_db, we're done. */
1532 if (ourstatus
->kind
== TARGET_WAITKIND_EXECD
)
1534 /* New image, it may or may not end up using thread_db. Assume
1535 not unless we find otherwise. */
1536 delete_thread_db_info (ptid_get_pid (ptid
));
1537 if (!thread_db_list
)
1538 unpush_target (&thread_db_ops
);
1540 /* Thread event breakpoints are deleted by
1541 update_breakpoints_after_exec. */
1546 /* If we do not know about the main thread yet, this would be a good time to
1548 if (ourstatus
->kind
== TARGET_WAITKIND_STOPPED
&& !have_threads (ptid
))
1549 thread_db_find_new_threads_1 (ptid
);
1551 if (ourstatus
->kind
== TARGET_WAITKIND_STOPPED
1552 && ourstatus
->value
.sig
== GDB_SIGNAL_TRAP
)
1553 /* Check for a thread event. */
1556 if (have_threads (ptid
))
1558 /* Fill in the thread's user-level thread id. */
1559 thread_from_lwp (ptid
);
1566 thread_db_mourn_inferior (struct target_ops
*ops
)
1568 struct target_ops
*target_beneath
= find_target_beneath (ops
);
1570 delete_thread_db_info (ptid_get_pid (inferior_ptid
));
1572 target_beneath
->to_mourn_inferior (target_beneath
);
1574 /* Delete the old thread event breakpoints. Do this after mourning
1575 the inferior, so that we don't try to uninsert them. */
1576 remove_thread_event_breakpoints ();
1578 /* Detach thread_db target ops. */
1579 if (!thread_db_list
)
1580 unpush_target (ops
);
1583 struct callback_data
1585 struct thread_db_info
*info
;
1590 find_new_threads_callback (const td_thrhandle_t
*th_p
, void *data
)
1595 struct thread_info
*tp
;
1596 struct callback_data
*cb_data
= data
;
1597 struct thread_db_info
*info
= cb_data
->info
;
1599 err
= info
->td_thr_get_info_p (th_p
, &ti
);
1601 error (_("find_new_threads_callback: cannot get thread info: %s"),
1602 thread_db_err_str (err
));
1606 /* A thread ID of zero means that this is the main thread, but
1607 glibc has not yet initialized thread-local storage and the
1608 pthread library. We do not know what the thread's TID will
1609 be yet. Just enable event reporting and otherwise ignore
1612 /* In that case, we're not stopped in a fork syscall and don't
1613 need this glibc bug workaround. */
1614 info
->need_stale_parent_threads_check
= 0;
1616 if (target_has_execution
)
1618 err
= info
->td_thr_event_enable_p (th_p
, 1);
1620 error (_("Cannot enable thread event reporting for LWP %d: %s"),
1621 (int) ti
.ti_lid
, thread_db_err_str (err
));
1627 /* Ignore stale parent threads, caused by glibc/BZ5983. This is a
1628 bit expensive, as it needs to open /proc/pid/status, so try to
1629 avoid doing the work if we know we don't have to. */
1630 if (info
->need_stale_parent_threads_check
)
1632 int tgid
= linux_proc_get_tgid (ti
.ti_lid
);
1634 if (tgid
!= -1 && tgid
!= info
->pid
)
1638 ptid
= ptid_build (info
->pid
, ti
.ti_lid
, 0);
1639 tp
= find_thread_ptid (ptid
);
1640 if (tp
== NULL
|| tp
->private == NULL
)
1642 if (attach_thread (ptid
, th_p
, &ti
))
1643 cb_data
->new_threads
+= 1;
1645 /* Problem attaching this thread; perhaps it exited before we
1647 This could mean that the thread list inside glibc itself is in
1648 inconsistent state, and libthread_db could go on looping forever
1649 (observed with glibc-2.3.6). To prevent that, terminate
1650 iteration: thread_db_find_new_threads_2 will retry. */
1657 /* Helper for thread_db_find_new_threads_2.
1658 Returns number of new threads found. */
1661 find_new_threads_once (struct thread_db_info
*info
, int iteration
,
1664 volatile struct gdb_exception except
;
1665 struct callback_data data
;
1666 td_err_e err
= TD_ERR
;
1669 data
.new_threads
= 0;
1671 TRY_CATCH (except
, RETURN_MASK_ERROR
)
1673 /* Iterate over all user-space threads to discover new threads. */
1674 err
= info
->td_ta_thr_iter_p (info
->thread_agent
,
1675 find_new_threads_callback
,
1678 TD_THR_LOWEST_PRIORITY
,
1680 TD_THR_ANY_USER_FLAGS
);
1683 if (libthread_db_debug
)
1685 if (except
.reason
< 0)
1686 exception_fprintf (gdb_stderr
, except
,
1687 "Warning: find_new_threads_once: ");
1689 printf_filtered (_("Found %d new threads in iteration %d.\n"),
1690 data
.new_threads
, iteration
);
1696 return data
.new_threads
;
1699 /* Search for new threads, accessing memory through stopped thread
1700 PTID. If UNTIL_NO_NEW is true, repeat searching until several
1701 searches in a row do not discover any new threads. */
1704 thread_db_find_new_threads_2 (ptid_t ptid
, int until_no_new
)
1706 td_err_e err
= TD_OK
;
1707 struct thread_db_info
*info
;
1710 info
= get_thread_db_info (ptid_get_pid (ptid
));
1712 /* Access an lwp we know is stopped. */
1713 info
->proc_handle
.ptid
= ptid
;
1717 /* Require 4 successive iterations which do not find any new threads.
1718 The 4 is a heuristic: there is an inherent race here, and I have
1719 seen that 2 iterations in a row are not always sufficient to
1720 "capture" all threads. */
1721 for (i
= 0, loop
= 0; loop
< 4 && err
== TD_OK
; ++i
, ++loop
)
1722 if (find_new_threads_once (info
, i
, &err
) != 0)
1724 /* Found some new threads. Restart the loop from beginning. */
1729 find_new_threads_once (info
, 0, &err
);
1732 error (_("Cannot find new threads: %s"), thread_db_err_str (err
));
1736 thread_db_find_new_threads_1 (ptid_t ptid
)
1738 thread_db_find_new_threads_2 (ptid
, 0);
1742 update_thread_core (struct lwp_info
*info
, void *closure
)
1744 info
->core
= linux_common_core_of_thread (info
->ptid
);
1749 thread_db_update_thread_list (struct target_ops
*ops
)
1751 struct thread_db_info
*info
;
1752 struct inferior
*inf
;
1758 struct thread_info
*thread
;
1763 info
= get_thread_db_info (inf
->pid
);
1767 thread
= any_live_thread_of_process (inf
->pid
);
1768 if (thread
== NULL
|| thread
->executing
)
1771 thread_db_find_new_threads_1 (thread
->ptid
);
1774 if (target_has_execution
)
1775 iterate_over_lwps (minus_one_ptid
/* iterate over all */,
1776 update_thread_core
, NULL
);
1780 thread_db_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
1782 struct thread_info
*thread_info
= find_thread_ptid (ptid
);
1783 struct target_ops
*beneath
;
1785 if (thread_info
!= NULL
&& thread_info
->private != NULL
)
1787 static char buf
[64];
1790 tid
= thread_info
->private->tid
;
1791 snprintf (buf
, sizeof (buf
), "Thread 0x%lx (LWP %ld)",
1792 tid
, ptid_get_lwp (ptid
));
1797 beneath
= find_target_beneath (ops
);
1798 return beneath
->to_pid_to_str (beneath
, ptid
);
1801 /* Return a string describing the state of the thread specified by
1805 thread_db_extra_thread_info (struct target_ops
*self
,
1806 struct thread_info
*info
)
1808 if (info
->private == NULL
)
1811 if (info
->private->dying
)
1817 /* Get the address of the thread local variable in load module LM which
1818 is stored at OFFSET within the thread local storage for thread PTID. */
1821 thread_db_get_thread_local_address (struct target_ops
*ops
,
1826 struct thread_info
*thread_info
;
1827 struct target_ops
*beneath
;
1829 /* If we have not discovered any threads yet, check now. */
1830 if (!have_threads (ptid
))
1831 thread_db_find_new_threads_1 (ptid
);
1833 /* Find the matching thread. */
1834 thread_info
= find_thread_ptid (ptid
);
1836 if (thread_info
!= NULL
&& thread_info
->private != NULL
)
1840 struct thread_db_info
*info
;
1842 info
= get_thread_db_info (ptid_get_pid (ptid
));
1844 /* Finally, get the address of the variable. */
1847 /* glibc doesn't provide the needed interface. */
1848 if (!info
->td_thr_tls_get_addr_p
)
1849 throw_error (TLS_NO_LIBRARY_SUPPORT_ERROR
,
1850 _("No TLS library support"));
1852 /* Note the cast through uintptr_t: this interface only works if
1853 a target address fits in a psaddr_t, which is a host pointer.
1854 So a 32-bit debugger can not access 64-bit TLS through this. */
1855 err
= info
->td_thr_tls_get_addr_p (&thread_info
->private->th
,
1856 (psaddr_t
)(uintptr_t) lm
,
1861 /* If glibc doesn't provide the needed interface throw an error
1862 that LM is zero - normally cases it should not be. */
1863 if (!info
->td_thr_tlsbase_p
)
1864 throw_error (TLS_LOAD_MODULE_NOT_FOUND_ERROR
,
1865 _("TLS load module not found"));
1867 /* This code path handles the case of -static -pthread executables:
1868 https://sourceware.org/ml/libc-help/2014-03/msg00024.html
1869 For older GNU libc r_debug.r_map is NULL. For GNU libc after
1870 PR libc/16831 due to GDB PR threads/16954 LOAD_MODULE is also NULL.
1871 The constant number 1 depends on GNU __libc_setup_tls
1872 initialization of l_tls_modid to 1. */
1873 err
= info
->td_thr_tlsbase_p (&thread_info
->private->th
,
1875 address
= (char *) address
+ offset
;
1878 #ifdef THREAD_DB_HAS_TD_NOTALLOC
1879 /* The memory hasn't been allocated, yet. */
1880 if (err
== TD_NOTALLOC
)
1881 /* Now, if libthread_db provided the initialization image's
1882 address, we *could* try to build a non-lvalue value from
1883 the initialization image. */
1884 throw_error (TLS_NOT_ALLOCATED_YET_ERROR
,
1885 _("TLS not allocated yet"));
1888 /* Something else went wrong. */
1890 throw_error (TLS_GENERIC_ERROR
,
1891 (("%s")), thread_db_err_str (err
));
1893 /* Cast assuming host == target. Joy. */
1894 /* Do proper sign extension for the target. */
1895 gdb_assert (exec_bfd
);
1896 return (bfd_get_sign_extend_vma (exec_bfd
) > 0
1897 ? (CORE_ADDR
) (intptr_t) address
1898 : (CORE_ADDR
) (uintptr_t) address
);
1901 beneath
= find_target_beneath (ops
);
1902 return beneath
->to_get_thread_local_address (beneath
, ptid
, lm
, offset
);
1905 /* Callback routine used to find a thread based on the TID part of
1909 thread_db_find_thread_from_tid (struct thread_info
*thread
, void *data
)
1911 long *tid
= (long *) data
;
1913 if (thread
->private->tid
== *tid
)
1919 /* Implement the to_get_ada_task_ptid target method for this target. */
1922 thread_db_get_ada_task_ptid (struct target_ops
*self
, long lwp
, long thread
)
1924 struct thread_info
*thread_info
;
1926 thread_db_find_new_threads_1 (inferior_ptid
);
1927 thread_info
= iterate_over_threads (thread_db_find_thread_from_tid
, &thread
);
1929 gdb_assert (thread_info
!= NULL
);
1931 return (thread_info
->ptid
);
1935 thread_db_resume (struct target_ops
*ops
,
1936 ptid_t ptid
, int step
, enum gdb_signal signo
)
1938 struct target_ops
*beneath
= find_target_beneath (ops
);
1939 struct thread_db_info
*info
;
1941 if (ptid_equal (ptid
, minus_one_ptid
))
1942 info
= get_thread_db_info (ptid_get_pid (inferior_ptid
));
1944 info
= get_thread_db_info (ptid_get_pid (ptid
));
1946 /* This workaround is only needed for child fork lwps stopped in a
1947 PTRACE_O_TRACEFORK event. When the inferior is resumed, the
1948 workaround can be disabled. */
1950 info
->need_stale_parent_threads_check
= 0;
1952 beneath
->to_resume (beneath
, ptid
, step
, signo
);
1955 /* qsort helper function for info_auto_load_libthread_db, sort the
1956 thread_db_info pointers primarily by their FILENAME and secondarily by their
1957 PID, both in ascending order. */
1960 info_auto_load_libthread_db_compare (const void *ap
, const void *bp
)
1962 struct thread_db_info
*a
= *(struct thread_db_info
**) ap
;
1963 struct thread_db_info
*b
= *(struct thread_db_info
**) bp
;
1966 retval
= strcmp (a
->filename
, b
->filename
);
1970 return (a
->pid
> b
->pid
) - (a
->pid
- b
->pid
);
1973 /* Implement 'info auto-load libthread-db'. */
1976 info_auto_load_libthread_db (char *args
, int from_tty
)
1978 struct ui_out
*uiout
= current_uiout
;
1979 const char *cs
= args
? args
: "";
1980 struct thread_db_info
*info
, **array
;
1981 unsigned info_count
, unique_filenames
;
1982 size_t max_filename_len
, max_pids_len
, pids_len
;
1983 struct cleanup
*back_to
;
1987 cs
= skip_spaces_const (cs
);
1989 error (_("'info auto-load libthread-db' does not accept any parameters"));
1992 for (info
= thread_db_list
; info
; info
= info
->next
)
1993 if (info
->filename
!= NULL
)
1996 array
= xmalloc (sizeof (*array
) * info_count
);
1997 back_to
= make_cleanup (xfree
, array
);
2000 for (info
= thread_db_list
; info
; info
= info
->next
)
2001 if (info
->filename
!= NULL
)
2002 array
[info_count
++] = info
;
2004 /* Sort ARRAY by filenames and PIDs. */
2006 qsort (array
, info_count
, sizeof (*array
),
2007 info_auto_load_libthread_db_compare
);
2009 /* Calculate the number of unique filenames (rows) and the maximum string
2010 length of PIDs list for the unique filenames (columns). */
2012 unique_filenames
= 0;
2013 max_filename_len
= 0;
2016 for (i
= 0; i
< info_count
; i
++)
2018 int pid
= array
[i
]->pid
;
2019 size_t this_pid_len
;
2021 for (this_pid_len
= 0; pid
!= 0; pid
/= 10)
2024 if (i
== 0 || strcmp (array
[i
- 1]->filename
, array
[i
]->filename
) != 0)
2027 max_filename_len
= max (max_filename_len
,
2028 strlen (array
[i
]->filename
));
2032 pids_len
-= strlen (", ");
2033 max_pids_len
= max (max_pids_len
, pids_len
);
2037 pids_len
+= this_pid_len
+ strlen (", ");
2041 pids_len
-= strlen (", ");
2042 max_pids_len
= max (max_pids_len
, pids_len
);
2045 /* Table header shifted right by preceding "libthread-db: " would not match
2047 if (info_count
> 0 && args
== auto_load_info_scripts_pattern_nl
)
2048 ui_out_text (uiout
, "\n");
2050 make_cleanup_ui_out_table_begin_end (uiout
, 2, unique_filenames
,
2051 "LinuxThreadDbTable");
2053 ui_out_table_header (uiout
, max_filename_len
, ui_left
, "filename",
2055 ui_out_table_header (uiout
, pids_len
, ui_left
, "PIDs", "Pids");
2056 ui_out_table_body (uiout
);
2058 pids
= xmalloc (max_pids_len
+ 1);
2059 make_cleanup (xfree
, pids
);
2061 /* Note I is incremented inside the cycle, not at its end. */
2062 for (i
= 0; i
< info_count
;)
2064 struct cleanup
*chain
= make_cleanup_ui_out_tuple_begin_end (uiout
, NULL
);
2068 ui_out_field_string (uiout
, "filename", info
->filename
);
2071 while (i
< info_count
&& strcmp (info
->filename
, array
[i
]->filename
) == 0)
2073 if (pids_end
!= pids
)
2078 pids_end
+= xsnprintf (pids_end
, &pids
[max_pids_len
+ 1] - pids_end
,
2079 "%u", array
[i
]->pid
);
2080 gdb_assert (pids_end
< &pids
[max_pids_len
+ 1]);
2086 ui_out_field_string (uiout
, "pids", pids
);
2088 ui_out_text (uiout
, "\n");
2089 do_cleanups (chain
);
2092 do_cleanups (back_to
);
2094 if (info_count
== 0)
2095 ui_out_message (uiout
, 0, _("No auto-loaded libthread-db.\n"));
2099 init_thread_db_ops (void)
2101 thread_db_ops
.to_shortname
= "multi-thread";
2102 thread_db_ops
.to_longname
= "multi-threaded child process.";
2103 thread_db_ops
.to_doc
= "Threads and pthreads support.";
2104 thread_db_ops
.to_detach
= thread_db_detach
;
2105 thread_db_ops
.to_wait
= thread_db_wait
;
2106 thread_db_ops
.to_resume
= thread_db_resume
;
2107 thread_db_ops
.to_mourn_inferior
= thread_db_mourn_inferior
;
2108 thread_db_ops
.to_update_thread_list
= thread_db_update_thread_list
;
2109 thread_db_ops
.to_pid_to_str
= thread_db_pid_to_str
;
2110 thread_db_ops
.to_stratum
= thread_stratum
;
2111 thread_db_ops
.to_has_thread_control
= tc_schedlock
;
2112 thread_db_ops
.to_get_thread_local_address
2113 = thread_db_get_thread_local_address
;
2114 thread_db_ops
.to_extra_thread_info
= thread_db_extra_thread_info
;
2115 thread_db_ops
.to_get_ada_task_ptid
= thread_db_get_ada_task_ptid
;
2116 thread_db_ops
.to_magic
= OPS_MAGIC
;
2118 complete_target_initialization (&thread_db_ops
);
2121 /* Provide a prototype to silence -Wmissing-prototypes. */
2122 extern initialize_file_ftype _initialize_thread_db
;
2125 _initialize_thread_db (void)
2127 init_thread_db_ops ();
2129 /* Defer loading of libthread_db.so until inferior is running.
2130 This allows gdb to load correct libthread_db for a given
2131 executable -- there could be mutiple versions of glibc,
2132 compiled with LinuxThreads or NPTL, and until there is
2133 a running inferior, we can't tell which libthread_db is
2134 the correct one to load. */
2136 libthread_db_search_path
= xstrdup (LIBTHREAD_DB_SEARCH_PATH
);
2138 add_setshow_optional_filename_cmd ("libthread-db-search-path",
2140 &libthread_db_search_path
, _("\
2141 Set search path for libthread_db."), _("\
2142 Show the current search path or libthread_db."), _("\
2143 This path is used to search for libthread_db to be loaded into \
2145 Its value is a colon (':') separate list of directories to search.\n\
2146 Setting the search path to an empty list resets it to its default value."),
2147 set_libthread_db_search_path
,
2149 &setlist
, &showlist
);
2151 add_setshow_zuinteger_cmd ("libthread-db", class_maintenance
,
2152 &libthread_db_debug
, _("\
2153 Set libthread-db debugging."), _("\
2154 Show libthread-db debugging."), _("\
2155 When non-zero, libthread-db debugging is enabled."),
2157 show_libthread_db_debug
,
2158 &setdebuglist
, &showdebuglist
);
2160 add_setshow_boolean_cmd ("libthread-db", class_support
,
2161 &auto_load_thread_db
, _("\
2162 Enable or disable auto-loading of inferior specific libthread_db."), _("\
2163 Show whether auto-loading inferior specific libthread_db is enabled."), _("\
2164 If enabled, libthread_db will be searched in 'set libthread-db-search-path'\n\
2165 locations to load libthread_db compatible with the inferior.\n\
2166 Standard system libthread_db still gets loaded even with this option off.\n\
2167 This options has security implications for untrusted inferiors."),
2168 NULL
, show_auto_load_thread_db
,
2169 auto_load_set_cmdlist_get (),
2170 auto_load_show_cmdlist_get ());
2172 add_cmd ("libthread-db", class_info
, info_auto_load_libthread_db
,
2173 _("Print the list of loaded inferior specific libthread_db.\n\
2174 Usage: info auto-load libthread-db"),
2175 auto_load_info_cmdlist_get ());
2177 /* Add ourselves to objfile event chain. */
2178 observer_attach_new_objfile (thread_db_new_objfile
);
2180 /* Add ourselves to inferior_created event chain.
2181 This is needed to handle debugging statically linked programs where
2182 the new_objfile observer won't get called for libpthread. */
2183 observer_attach_inferior_created (thread_db_inferior_created
);