1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2019 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/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
28 #include <sys/syscall.h>
29 #include "nat/gdb_ptrace.h"
30 #include "linux-nat.h"
31 #include "nat/linux-ptrace.h"
32 #include "nat/linux-procfs.h"
33 #include "nat/linux-personality.h"
34 #include "linux-fork.h"
35 #include "gdbthread.h"
39 #include "inf-child.h"
40 #include "inf-ptrace.h"
42 #include <sys/procfs.h> /* for elf_gregset etc. */
43 #include "elf-bfd.h" /* for elfcore_write_* */
44 #include "gregset.h" /* for gregset */
45 #include "gdbcore.h" /* for get_exec_file */
46 #include <ctype.h> /* for isdigit */
47 #include <sys/stat.h> /* for struct stat */
48 #include <fcntl.h> /* for O_RDONLY */
50 #include "event-loop.h"
51 #include "event-top.h"
53 #include <sys/types.h>
55 #include "xml-support.h"
58 #include "nat/linux-osdata.h"
59 #include "linux-tdep.h"
62 #include "tracepoint.h"
64 #include "target-descriptions.h"
65 #include "filestuff.h"
67 #include "nat/linux-namespaces.h"
71 #define SPUFS_MAGIC 0x23c9b64e
74 /* This comment documents high-level logic of this file.
76 Waiting for events in sync mode
77 ===============================
79 When waiting for an event in a specific thread, we just use waitpid,
80 passing the specific pid, and not passing WNOHANG.
82 When waiting for an event in all threads, waitpid is not quite good:
84 - If the thread group leader exits while other threads in the thread
85 group still exist, waitpid(TGID, ...) hangs. That waitpid won't
86 return an exit status until the other threads in the group are
89 - When a non-leader thread execs, that thread just vanishes without
90 reporting an exit (so we'd hang if we waited for it explicitly in
91 that case). The exec event is instead reported to the TGID pid.
93 The solution is to always use -1 and WNOHANG, together with
96 First, we use non-blocking waitpid to check for events. If nothing is
97 found, we use sigsuspend to wait for SIGCHLD. When SIGCHLD arrives,
98 it means something happened to a child process. As soon as we know
99 there's an event, we get back to calling nonblocking waitpid.
101 Note that SIGCHLD should be blocked between waitpid and sigsuspend
102 calls, so that we don't miss a signal. If SIGCHLD arrives in between,
103 when it's blocked, the signal becomes pending and sigsuspend
104 immediately notices it and returns.
106 Waiting for events in async mode (TARGET_WNOHANG)
107 =================================================
109 In async mode, GDB should always be ready to handle both user input
110 and target events, so neither blocking waitpid nor sigsuspend are
111 viable options. Instead, we should asynchronously notify the GDB main
112 event loop whenever there's an unprocessed event from the target. We
113 detect asynchronous target events by handling SIGCHLD signals. To
114 notify the event loop about target events, the self-pipe trick is used
115 --- a pipe is registered as waitable event source in the event loop,
116 the event loop select/poll's on the read end of this pipe (as well on
117 other event sources, e.g., stdin), and the SIGCHLD handler writes a
118 byte to this pipe. This is more portable than relying on
119 pselect/ppoll, since on kernels that lack those syscalls, libc
120 emulates them with select/poll+sigprocmask, and that is racy
121 (a.k.a. plain broken).
123 Obviously, if we fail to notify the event loop if there's a target
124 event, it's bad. OTOH, if we notify the event loop when there's no
125 event from the target, linux_nat_wait will detect that there's no real
126 event to report, and return event of type TARGET_WAITKIND_IGNORE.
127 This is mostly harmless, but it will waste time and is better avoided.
129 The main design point is that every time GDB is outside linux-nat.c,
130 we have a SIGCHLD handler installed that is called when something
131 happens to the target and notifies the GDB event loop. Whenever GDB
132 core decides to handle the event, and calls into linux-nat.c, we
133 process things as in sync mode, except that the we never block in
136 While processing an event, we may end up momentarily blocked in
137 waitpid calls. Those waitpid calls, while blocking, are guarantied to
138 return quickly. E.g., in all-stop mode, before reporting to the core
139 that an LWP hit a breakpoint, all LWPs are stopped by sending them
140 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
141 Note that this is different from blocking indefinitely waiting for the
142 next event --- here, we're already handling an event.
147 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
148 signal is not entirely significant; we just need for a signal to be delivered,
149 so that we can intercept it. SIGSTOP's advantage is that it can not be
150 blocked. A disadvantage is that it is not a real-time signal, so it can only
151 be queued once; we do not keep track of other sources of SIGSTOP.
153 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
154 use them, because they have special behavior when the signal is generated -
155 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
156 kills the entire thread group.
158 A delivered SIGSTOP would stop the entire thread group, not just the thread we
159 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
160 cancel it (by PTRACE_CONT without passing SIGSTOP).
162 We could use a real-time signal instead. This would solve those problems; we
163 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
164 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
165 generates it, and there are races with trying to find a signal that is not
171 The case of a thread group (process) with 3 or more threads, and a
172 thread other than the leader execs is worth detailing:
174 On an exec, the Linux kernel destroys all threads except the execing
175 one in the thread group, and resets the execing thread's tid to the
176 tgid. No exit notification is sent for the execing thread -- from the
177 ptracer's perspective, it appears as though the execing thread just
178 vanishes. Until we reap all other threads except the leader and the
179 execing thread, the leader will be zombie, and the execing thread will
180 be in `D (disc sleep)' state. As soon as all other threads are
181 reaped, the execing thread changes its tid to the tgid, and the
182 previous (zombie) leader vanishes, giving place to the "new"
186 #define O_LARGEFILE 0
189 struct linux_nat_target
*linux_target
;
191 /* Does the current host support PTRACE_GETREGSET? */
192 enum tribool have_ptrace_getregset
= TRIBOOL_UNKNOWN
;
194 static unsigned int debug_linux_nat
;
196 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
197 struct cmd_list_element
*c
, const char *value
)
199 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
203 struct simple_pid_list
207 struct simple_pid_list
*next
;
209 struct simple_pid_list
*stopped_pids
;
211 /* Whether target_thread_events is in effect. */
212 static int report_thread_events
;
214 /* Async mode support. */
216 /* The read/write ends of the pipe registered as waitable file in the
218 static int linux_nat_event_pipe
[2] = { -1, -1 };
220 /* True if we're currently in async mode. */
221 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
223 /* Flush the event pipe. */
226 async_file_flush (void)
233 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
235 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
238 /* Put something (anything, doesn't matter what, or how much) in event
239 pipe, so that the select/poll in the event-loop realizes we have
240 something to process. */
243 async_file_mark (void)
247 /* It doesn't really matter what the pipe contains, as long we end
248 up with something in it. Might as well flush the previous
254 ret
= write (linux_nat_event_pipe
[1], "+", 1);
256 while (ret
== -1 && errno
== EINTR
);
258 /* Ignore EAGAIN. If the pipe is full, the event loop will already
259 be awakened anyway. */
262 static int kill_lwp (int lwpid
, int signo
);
264 static int stop_callback (struct lwp_info
*lp
, void *data
);
265 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
);
267 static void block_child_signals (sigset_t
*prev_mask
);
268 static void restore_child_signals_mask (sigset_t
*prev_mask
);
271 static struct lwp_info
*add_lwp (ptid_t ptid
);
272 static void purge_lwp_list (int pid
);
273 static void delete_lwp (ptid_t ptid
);
274 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
276 static int lwp_status_pending_p (struct lwp_info
*lp
);
278 static void save_stop_reason (struct lwp_info
*lp
);
283 /* See nat/linux-nat.h. */
286 ptid_of_lwp (struct lwp_info
*lwp
)
291 /* See nat/linux-nat.h. */
294 lwp_set_arch_private_info (struct lwp_info
*lwp
,
295 struct arch_lwp_info
*info
)
297 lwp
->arch_private
= info
;
300 /* See nat/linux-nat.h. */
302 struct arch_lwp_info
*
303 lwp_arch_private_info (struct lwp_info
*lwp
)
305 return lwp
->arch_private
;
308 /* See nat/linux-nat.h. */
311 lwp_is_stopped (struct lwp_info
*lwp
)
316 /* See nat/linux-nat.h. */
318 enum target_stop_reason
319 lwp_stop_reason (struct lwp_info
*lwp
)
321 return lwp
->stop_reason
;
324 /* See nat/linux-nat.h. */
327 lwp_is_stepping (struct lwp_info
*lwp
)
333 /* Trivial list manipulation functions to keep track of a list of
334 new stopped processes. */
336 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
338 struct simple_pid_list
*new_pid
= XNEW (struct simple_pid_list
);
341 new_pid
->status
= status
;
342 new_pid
->next
= *listp
;
347 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
349 struct simple_pid_list
**p
;
351 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
352 if ((*p
)->pid
== pid
)
354 struct simple_pid_list
*next
= (*p
)->next
;
356 *statusp
= (*p
)->status
;
364 /* Return the ptrace options that we want to try to enable. */
367 linux_nat_ptrace_options (int attached
)
372 options
|= PTRACE_O_EXITKILL
;
374 options
|= (PTRACE_O_TRACESYSGOOD
375 | PTRACE_O_TRACEVFORKDONE
376 | PTRACE_O_TRACEVFORK
378 | PTRACE_O_TRACEEXEC
);
383 /* Initialize ptrace and procfs warnings and check for supported
384 ptrace features given PID.
386 ATTACHED should be nonzero iff we attached to the inferior. */
389 linux_init_ptrace_procfs (pid_t pid
, int attached
)
391 int options
= linux_nat_ptrace_options (attached
);
393 linux_enable_event_reporting (pid
, options
);
394 linux_ptrace_init_warnings ();
395 linux_proc_init_warnings ();
398 linux_nat_target::~linux_nat_target ()
402 linux_nat_target::post_attach (int pid
)
404 linux_init_ptrace_procfs (pid
, 1);
408 linux_nat_target::post_startup_inferior (ptid_t ptid
)
410 linux_init_ptrace_procfs (ptid
.pid (), 0);
413 /* Return the number of known LWPs in the tgid given by PID. */
421 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
422 if (lp
->ptid
.pid () == pid
)
428 /* Deleter for lwp_info unique_ptr specialisation. */
432 void operator() (struct lwp_info
*lwp
) const
434 delete_lwp (lwp
->ptid
);
438 /* A unique_ptr specialisation for lwp_info. */
440 typedef std::unique_ptr
<struct lwp_info
, lwp_deleter
> lwp_info_up
;
442 /* Target hook for follow_fork. On entry inferior_ptid must be the
443 ptid of the followed inferior. At return, inferior_ptid will be
447 linux_nat_target::follow_fork (int follow_child
, int detach_fork
)
451 struct lwp_info
*child_lp
= NULL
;
453 ptid_t parent_ptid
, child_ptid
;
454 int parent_pid
, child_pid
;
456 has_vforked
= (inferior_thread ()->pending_follow
.kind
457 == TARGET_WAITKIND_VFORKED
);
458 parent_ptid
= inferior_ptid
;
459 child_ptid
= inferior_thread ()->pending_follow
.value
.related_pid
;
460 parent_pid
= parent_ptid
.lwp ();
461 child_pid
= child_ptid
.lwp ();
463 /* We're already attached to the parent, by default. */
464 child_lp
= add_lwp (child_ptid
);
465 child_lp
->stopped
= 1;
466 child_lp
->last_resume_kind
= resume_stop
;
468 /* Detach new forked process? */
471 int child_stop_signal
= 0;
472 bool detach_child
= true;
474 /* Move CHILD_LP into a unique_ptr and clear the source pointer
475 to prevent us doing anything stupid with it. */
476 lwp_info_up
child_lp_ptr (child_lp
);
479 linux_target
->low_prepare_to_resume (child_lp_ptr
.get ());
481 /* When debugging an inferior in an architecture that supports
482 hardware single stepping on a kernel without commit
483 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
484 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
485 set if the parent process had them set.
486 To work around this, single step the child process
487 once before detaching to clear the flags. */
489 /* Note that we consult the parent's architecture instead of
490 the child's because there's no inferior for the child at
492 if (!gdbarch_software_single_step_p (target_thread_architecture
497 linux_disable_event_reporting (child_pid
);
498 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
499 perror_with_name (_("Couldn't do single step"));
500 if (my_waitpid (child_pid
, &status
, 0) < 0)
501 perror_with_name (_("Couldn't wait vfork process"));
504 detach_child
= WIFSTOPPED (status
);
505 child_stop_signal
= WSTOPSIG (status
);
511 int signo
= child_stop_signal
;
514 && !signal_pass_state (gdb_signal_from_host (signo
)))
516 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
521 scoped_restore save_inferior_ptid
522 = make_scoped_restore (&inferior_ptid
);
523 inferior_ptid
= child_ptid
;
525 /* Let the thread_db layer learn about this new process. */
526 check_for_thread_db ();
531 struct lwp_info
*parent_lp
;
533 parent_lp
= find_lwp_pid (parent_ptid
);
534 gdb_assert (linux_supports_tracefork () >= 0);
536 if (linux_supports_tracevforkdone ())
539 fprintf_unfiltered (gdb_stdlog
,
540 "LCFF: waiting for VFORK_DONE on %d\n",
542 parent_lp
->stopped
= 1;
544 /* We'll handle the VFORK_DONE event like any other
545 event, in target_wait. */
549 /* We can't insert breakpoints until the child has
550 finished with the shared memory region. We need to
551 wait until that happens. Ideal would be to just
553 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
554 - waitpid (parent_pid, &status, __WALL);
555 However, most architectures can't handle a syscall
556 being traced on the way out if it wasn't traced on
559 We might also think to loop, continuing the child
560 until it exits or gets a SIGTRAP. One problem is
561 that the child might call ptrace with PTRACE_TRACEME.
563 There's no simple and reliable way to figure out when
564 the vforked child will be done with its copy of the
565 shared memory. We could step it out of the syscall,
566 two instructions, let it go, and then single-step the
567 parent once. When we have hardware single-step, this
568 would work; with software single-step it could still
569 be made to work but we'd have to be able to insert
570 single-step breakpoints in the child, and we'd have
571 to insert -just- the single-step breakpoint in the
572 parent. Very awkward.
574 In the end, the best we can do is to make sure it
575 runs for a little while. Hopefully it will be out of
576 range of any breakpoints we reinsert. Usually this
577 is only the single-step breakpoint at vfork's return
581 fprintf_unfiltered (gdb_stdlog
,
582 "LCFF: no VFORK_DONE "
583 "support, sleeping a bit\n");
587 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
588 and leave it pending. The next linux_nat_resume call
589 will notice a pending event, and bypasses actually
590 resuming the inferior. */
591 parent_lp
->status
= 0;
592 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
593 parent_lp
->stopped
= 1;
595 /* If we're in async mode, need to tell the event loop
596 there's something here to process. */
597 if (target_is_async_p ())
604 struct lwp_info
*child_lp
;
606 child_lp
= add_lwp (inferior_ptid
);
607 child_lp
->stopped
= 1;
608 child_lp
->last_resume_kind
= resume_stop
;
610 /* Let the thread_db layer learn about this new process. */
611 check_for_thread_db ();
619 linux_nat_target::insert_fork_catchpoint (int pid
)
621 return !linux_supports_tracefork ();
625 linux_nat_target::remove_fork_catchpoint (int pid
)
631 linux_nat_target::insert_vfork_catchpoint (int pid
)
633 return !linux_supports_tracefork ();
637 linux_nat_target::remove_vfork_catchpoint (int pid
)
643 linux_nat_target::insert_exec_catchpoint (int pid
)
645 return !linux_supports_tracefork ();
649 linux_nat_target::remove_exec_catchpoint (int pid
)
655 linux_nat_target::set_syscall_catchpoint (int pid
, bool needed
, int any_count
,
656 gdb::array_view
<const int> syscall_counts
)
658 if (!linux_supports_tracesysgood ())
661 /* On GNU/Linux, we ignore the arguments. It means that we only
662 enable the syscall catchpoints, but do not disable them.
664 Also, we do not use the `syscall_counts' information because we do not
665 filter system calls here. We let GDB do the logic for us. */
669 /* List of known LWPs, keyed by LWP PID. This speeds up the common
670 case of mapping a PID returned from the kernel to our corresponding
671 lwp_info data structure. */
672 static htab_t lwp_lwpid_htab
;
674 /* Calculate a hash from a lwp_info's LWP PID. */
677 lwp_info_hash (const void *ap
)
679 const struct lwp_info
*lp
= (struct lwp_info
*) ap
;
680 pid_t pid
= lp
->ptid
.lwp ();
682 return iterative_hash_object (pid
, 0);
685 /* Equality function for the lwp_info hash table. Compares the LWP's
689 lwp_lwpid_htab_eq (const void *a
, const void *b
)
691 const struct lwp_info
*entry
= (const struct lwp_info
*) a
;
692 const struct lwp_info
*element
= (const struct lwp_info
*) b
;
694 return entry
->ptid
.lwp () == element
->ptid
.lwp ();
697 /* Create the lwp_lwpid_htab hash table. */
700 lwp_lwpid_htab_create (void)
702 lwp_lwpid_htab
= htab_create (100, lwp_info_hash
, lwp_lwpid_htab_eq
, NULL
);
705 /* Add LP to the hash table. */
708 lwp_lwpid_htab_add_lwp (struct lwp_info
*lp
)
712 slot
= htab_find_slot (lwp_lwpid_htab
, lp
, INSERT
);
713 gdb_assert (slot
!= NULL
&& *slot
== NULL
);
717 /* Head of doubly-linked list of known LWPs. Sorted by reverse
718 creation order. This order is assumed in some cases. E.g.,
719 reaping status after killing alls lwps of a process: the leader LWP
720 must be reaped last. */
721 struct lwp_info
*lwp_list
;
723 /* Add LP to sorted-by-reverse-creation-order doubly-linked list. */
726 lwp_list_add (struct lwp_info
*lp
)
729 if (lwp_list
!= NULL
)
734 /* Remove LP from sorted-by-reverse-creation-order doubly-linked
738 lwp_list_remove (struct lwp_info
*lp
)
740 /* Remove from sorted-by-creation-order list. */
741 if (lp
->next
!= NULL
)
742 lp
->next
->prev
= lp
->prev
;
743 if (lp
->prev
!= NULL
)
744 lp
->prev
->next
= lp
->next
;
751 /* Original signal mask. */
752 static sigset_t normal_mask
;
754 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
755 _initialize_linux_nat. */
756 static sigset_t suspend_mask
;
758 /* Signals to block to make that sigsuspend work. */
759 static sigset_t blocked_mask
;
761 /* SIGCHLD action. */
762 struct sigaction sigchld_action
;
764 /* Block child signals (SIGCHLD and linux threads signals), and store
765 the previous mask in PREV_MASK. */
768 block_child_signals (sigset_t
*prev_mask
)
770 /* Make sure SIGCHLD is blocked. */
771 if (!sigismember (&blocked_mask
, SIGCHLD
))
772 sigaddset (&blocked_mask
, SIGCHLD
);
774 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
777 /* Restore child signals mask, previously returned by
778 block_child_signals. */
781 restore_child_signals_mask (sigset_t
*prev_mask
)
783 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
786 /* Mask of signals to pass directly to the inferior. */
787 static sigset_t pass_mask
;
789 /* Update signals to pass to the inferior. */
791 linux_nat_target::pass_signals (int numsigs
, unsigned char *pass_signals
)
795 sigemptyset (&pass_mask
);
797 for (signo
= 1; signo
< NSIG
; signo
++)
799 int target_signo
= gdb_signal_from_host (signo
);
800 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
801 sigaddset (&pass_mask
, signo
);
807 /* Prototypes for local functions. */
808 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
809 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
);
810 static int check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
);
814 /* Destroy and free LP. */
817 lwp_free (struct lwp_info
*lp
)
819 /* Let the arch specific bits release arch_lwp_info. */
820 linux_target
->low_delete_thread (lp
->arch_private
);
825 /* Traversal function for purge_lwp_list. */
828 lwp_lwpid_htab_remove_pid (void **slot
, void *info
)
830 struct lwp_info
*lp
= (struct lwp_info
*) *slot
;
831 int pid
= *(int *) info
;
833 if (lp
->ptid
.pid () == pid
)
835 htab_clear_slot (lwp_lwpid_htab
, slot
);
836 lwp_list_remove (lp
);
843 /* Remove all LWPs belong to PID from the lwp list. */
846 purge_lwp_list (int pid
)
848 htab_traverse_noresize (lwp_lwpid_htab
, lwp_lwpid_htab_remove_pid
, &pid
);
851 /* Add the LWP specified by PTID to the list. PTID is the first LWP
852 in the process. Return a pointer to the structure describing the
855 This differs from add_lwp in that we don't let the arch specific
856 bits know about this new thread. Current clients of this callback
857 take the opportunity to install watchpoints in the new thread, and
858 we shouldn't do that for the first thread. If we're spawning a
859 child ("run"), the thread executes the shell wrapper first, and we
860 shouldn't touch it until it execs the program we want to debug.
861 For "attach", it'd be okay to call the callback, but it's not
862 necessary, because watchpoints can't yet have been inserted into
865 static struct lwp_info
*
866 add_initial_lwp (ptid_t ptid
)
870 gdb_assert (ptid
.lwp_p ());
872 lp
= XNEW (struct lwp_info
);
874 memset (lp
, 0, sizeof (struct lwp_info
));
876 lp
->last_resume_kind
= resume_continue
;
877 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
882 /* Add to sorted-by-reverse-creation-order list. */
885 /* Add to keyed-by-pid htab. */
886 lwp_lwpid_htab_add_lwp (lp
);
891 /* Add the LWP specified by PID to the list. Return a pointer to the
892 structure describing the new LWP. The LWP should already be
895 static struct lwp_info
*
896 add_lwp (ptid_t ptid
)
900 lp
= add_initial_lwp (ptid
);
902 /* Let the arch specific bits know about this new thread. Current
903 clients of this callback take the opportunity to install
904 watchpoints in the new thread. We don't do this for the first
905 thread though. See add_initial_lwp. */
906 linux_target
->low_new_thread (lp
);
911 /* Remove the LWP specified by PID from the list. */
914 delete_lwp (ptid_t ptid
)
918 struct lwp_info dummy
;
921 slot
= htab_find_slot (lwp_lwpid_htab
, &dummy
, NO_INSERT
);
925 lp
= *(struct lwp_info
**) slot
;
926 gdb_assert (lp
!= NULL
);
928 htab_clear_slot (lwp_lwpid_htab
, slot
);
930 /* Remove from sorted-by-creation-order list. */
931 lwp_list_remove (lp
);
937 /* Return a pointer to the structure describing the LWP corresponding
938 to PID. If no corresponding LWP could be found, return NULL. */
940 static struct lwp_info
*
941 find_lwp_pid (ptid_t ptid
)
945 struct lwp_info dummy
;
952 dummy
.ptid
= ptid_t (0, lwp
, 0);
953 lp
= (struct lwp_info
*) htab_find (lwp_lwpid_htab
, &dummy
);
957 /* See nat/linux-nat.h. */
960 iterate_over_lwps (ptid_t filter
,
961 iterate_over_lwps_ftype callback
,
964 struct lwp_info
*lp
, *lpnext
;
966 for (lp
= lwp_list
; lp
; lp
= lpnext
)
970 if (lp
->ptid
.matches (filter
))
972 if ((*callback
) (lp
, data
) != 0)
980 /* Update our internal state when changing from one checkpoint to
981 another indicated by NEW_PTID. We can only switch single-threaded
982 applications, so we only create one new LWP, and the previous list
986 linux_nat_switch_fork (ptid_t new_ptid
)
990 purge_lwp_list (inferior_ptid
.pid ());
992 lp
= add_lwp (new_ptid
);
995 /* This changes the thread's ptid while preserving the gdb thread
996 num. Also changes the inferior pid, while preserving the
998 thread_change_ptid (inferior_ptid
, new_ptid
);
1000 /* We've just told GDB core that the thread changed target id, but,
1001 in fact, it really is a different thread, with different register
1003 registers_changed ();
1006 /* Handle the exit of a single thread LP. */
1009 exit_lwp (struct lwp_info
*lp
)
1011 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1015 if (print_thread_events
)
1016 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
1021 delete_lwp (lp
->ptid
);
1024 /* Wait for the LWP specified by LP, which we have just attached to.
1025 Returns a wait status for that LWP, to cache. */
1028 linux_nat_post_attach_wait (ptid_t ptid
, int *signalled
)
1030 pid_t new_pid
, pid
= ptid
.lwp ();
1033 if (linux_proc_pid_is_stopped (pid
))
1035 if (debug_linux_nat
)
1036 fprintf_unfiltered (gdb_stdlog
,
1037 "LNPAW: Attaching to a stopped process\n");
1039 /* The process is definitely stopped. It is in a job control
1040 stop, unless the kernel predates the TASK_STOPPED /
1041 TASK_TRACED distinction, in which case it might be in a
1042 ptrace stop. Make sure it is in a ptrace stop; from there we
1043 can kill it, signal it, et cetera.
1045 First make sure there is a pending SIGSTOP. Since we are
1046 already attached, the process can not transition from stopped
1047 to running without a PTRACE_CONT; so we know this signal will
1048 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1049 probably already in the queue (unless this kernel is old
1050 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1051 is not an RT signal, it can only be queued once. */
1052 kill_lwp (pid
, SIGSTOP
);
1054 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1055 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1056 ptrace (PTRACE_CONT
, pid
, 0, 0);
1059 /* Make sure the initial process is stopped. The user-level threads
1060 layer might want to poke around in the inferior, and that won't
1061 work if things haven't stabilized yet. */
1062 new_pid
= my_waitpid (pid
, &status
, __WALL
);
1063 gdb_assert (pid
== new_pid
);
1065 if (!WIFSTOPPED (status
))
1067 /* The pid we tried to attach has apparently just exited. */
1068 if (debug_linux_nat
)
1069 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1070 pid
, status_to_str (status
));
1074 if (WSTOPSIG (status
) != SIGSTOP
)
1077 if (debug_linux_nat
)
1078 fprintf_unfiltered (gdb_stdlog
,
1079 "LNPAW: Received %s after attaching\n",
1080 status_to_str (status
));
1087 linux_nat_target::create_inferior (const char *exec_file
,
1088 const std::string
&allargs
,
1089 char **env
, int from_tty
)
1091 maybe_disable_address_space_randomization restore_personality
1092 (disable_randomization
);
1094 /* The fork_child mechanism is synchronous and calls target_wait, so
1095 we have to mask the async mode. */
1097 /* Make sure we report all signals during startup. */
1098 pass_signals (0, NULL
);
1100 inf_ptrace_target::create_inferior (exec_file
, allargs
, env
, from_tty
);
1103 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1104 already attached. Returns true if a new LWP is found, false
1108 attach_proc_task_lwp_callback (ptid_t ptid
)
1110 struct lwp_info
*lp
;
1112 /* Ignore LWPs we're already attached to. */
1113 lp
= find_lwp_pid (ptid
);
1116 int lwpid
= ptid
.lwp ();
1118 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1122 /* Be quiet if we simply raced with the thread exiting.
1123 EPERM is returned if the thread's task still exists, and
1124 is marked as exited or zombie, as well as other
1125 conditions, so in that case, confirm the status in
1126 /proc/PID/status. */
1128 || (err
== EPERM
&& linux_proc_pid_is_gone (lwpid
)))
1130 if (debug_linux_nat
)
1132 fprintf_unfiltered (gdb_stdlog
,
1133 "Cannot attach to lwp %d: "
1134 "thread is gone (%d: %s)\n",
1135 lwpid
, err
, safe_strerror (err
));
1141 = linux_ptrace_attach_fail_reason_string (ptid
, err
);
1143 warning (_("Cannot attach to lwp %d: %s"),
1144 lwpid
, reason
.c_str ());
1149 if (debug_linux_nat
)
1150 fprintf_unfiltered (gdb_stdlog
,
1151 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1152 target_pid_to_str (ptid
));
1154 lp
= add_lwp (ptid
);
1156 /* The next time we wait for this LWP we'll see a SIGSTOP as
1157 PTRACE_ATTACH brings it to a halt. */
1160 /* We need to wait for a stop before being able to make the
1161 next ptrace call on this LWP. */
1162 lp
->must_set_ptrace_flags
= 1;
1164 /* So that wait collects the SIGSTOP. */
1167 /* Also add the LWP to gdb's thread list, in case a
1168 matching libthread_db is not found (or the process uses
1170 add_thread (lp
->ptid
);
1171 set_running (lp
->ptid
, 1);
1172 set_executing (lp
->ptid
, 1);
1181 linux_nat_target::attach (const char *args
, int from_tty
)
1183 struct lwp_info
*lp
;
1187 /* Make sure we report all signals during attach. */
1188 pass_signals (0, NULL
);
1192 inf_ptrace_target::attach (args
, from_tty
);
1194 CATCH (ex
, RETURN_MASK_ERROR
)
1196 pid_t pid
= parse_pid_to_attach (args
);
1197 std::string reason
= linux_ptrace_attach_fail_reason (pid
);
1199 if (!reason
.empty ())
1200 throw_error (ex
.error
, "warning: %s\n%s", reason
.c_str (), ex
.message
);
1202 throw_error (ex
.error
, "%s", ex
.message
);
1206 /* The ptrace base target adds the main thread with (pid,0,0)
1207 format. Decorate it with lwp info. */
1208 ptid
= ptid_t (inferior_ptid
.pid (),
1209 inferior_ptid
.pid (),
1211 thread_change_ptid (inferior_ptid
, ptid
);
1213 /* Add the initial process as the first LWP to the list. */
1214 lp
= add_initial_lwp (ptid
);
1216 status
= linux_nat_post_attach_wait (lp
->ptid
, &lp
->signalled
);
1217 if (!WIFSTOPPED (status
))
1219 if (WIFEXITED (status
))
1221 int exit_code
= WEXITSTATUS (status
);
1223 target_terminal::ours ();
1224 target_mourn_inferior (inferior_ptid
);
1226 error (_("Unable to attach: program exited normally."));
1228 error (_("Unable to attach: program exited with code %d."),
1231 else if (WIFSIGNALED (status
))
1233 enum gdb_signal signo
;
1235 target_terminal::ours ();
1236 target_mourn_inferior (inferior_ptid
);
1238 signo
= gdb_signal_from_host (WTERMSIG (status
));
1239 error (_("Unable to attach: program terminated with signal "
1241 gdb_signal_to_name (signo
),
1242 gdb_signal_to_string (signo
));
1245 internal_error (__FILE__
, __LINE__
,
1246 _("unexpected status %d for PID %ld"),
1247 status
, (long) ptid
.lwp ());
1252 /* Save the wait status to report later. */
1254 if (debug_linux_nat
)
1255 fprintf_unfiltered (gdb_stdlog
,
1256 "LNA: waitpid %ld, saving status %s\n",
1257 (long) lp
->ptid
.pid (), status_to_str (status
));
1259 lp
->status
= status
;
1261 /* We must attach to every LWP. If /proc is mounted, use that to
1262 find them now. The inferior may be using raw clone instead of
1263 using pthreads. But even if it is using pthreads, thread_db
1264 walks structures in the inferior's address space to find the list
1265 of threads/LWPs, and those structures may well be corrupted.
1266 Note that once thread_db is loaded, we'll still use it to list
1267 threads and associate pthread info with each LWP. */
1268 linux_proc_attach_tgid_threads (lp
->ptid
.pid (),
1269 attach_proc_task_lwp_callback
);
1271 if (target_can_async_p ())
1275 /* Get pending signal of THREAD as a host signal number, for detaching
1276 purposes. This is the signal the thread last stopped for, which we
1277 need to deliver to the thread when detaching, otherwise, it'd be
1281 get_detach_signal (struct lwp_info
*lp
)
1283 enum gdb_signal signo
= GDB_SIGNAL_0
;
1285 /* If we paused threads momentarily, we may have stored pending
1286 events in lp->status or lp->waitstatus (see stop_wait_callback),
1287 and GDB core hasn't seen any signal for those threads.
1288 Otherwise, the last signal reported to the core is found in the
1289 thread object's stop_signal.
1291 There's a corner case that isn't handled here at present. Only
1292 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1293 stop_signal make sense as a real signal to pass to the inferior.
1294 Some catchpoint related events, like
1295 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1296 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1297 those traps are debug API (ptrace in our case) related and
1298 induced; the inferior wouldn't see them if it wasn't being
1299 traced. Hence, we should never pass them to the inferior, even
1300 when set to pass state. Since this corner case isn't handled by
1301 infrun.c when proceeding with a signal, for consistency, neither
1302 do we handle it here (or elsewhere in the file we check for
1303 signal pass state). Normally SIGTRAP isn't set to pass state, so
1304 this is really a corner case. */
1306 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1307 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1308 else if (lp
->status
)
1309 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1312 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1314 if (target_is_non_stop_p () && !tp
->executing
)
1316 if (tp
->suspend
.waitstatus_pending_p
)
1317 signo
= tp
->suspend
.waitstatus
.value
.sig
;
1319 signo
= tp
->suspend
.stop_signal
;
1321 else if (!target_is_non_stop_p ())
1323 struct target_waitstatus last
;
1326 get_last_target_status (&last_ptid
, &last
);
1328 if (lp
->ptid
.lwp () == last_ptid
.lwp ())
1329 signo
= tp
->suspend
.stop_signal
;
1333 if (signo
== GDB_SIGNAL_0
)
1335 if (debug_linux_nat
)
1336 fprintf_unfiltered (gdb_stdlog
,
1337 "GPT: lwp %s has no pending signal\n",
1338 target_pid_to_str (lp
->ptid
));
1340 else if (!signal_pass_state (signo
))
1342 if (debug_linux_nat
)
1343 fprintf_unfiltered (gdb_stdlog
,
1344 "GPT: lwp %s had signal %s, "
1345 "but it is in no pass state\n",
1346 target_pid_to_str (lp
->ptid
),
1347 gdb_signal_to_string (signo
));
1351 if (debug_linux_nat
)
1352 fprintf_unfiltered (gdb_stdlog
,
1353 "GPT: lwp %s has pending signal %s\n",
1354 target_pid_to_str (lp
->ptid
),
1355 gdb_signal_to_string (signo
));
1357 return gdb_signal_to_host (signo
);
1363 /* Detach from LP. If SIGNO_P is non-NULL, then it points to the
1364 signal number that should be passed to the LWP when detaching.
1365 Otherwise pass any pending signal the LWP may have, if any. */
1368 detach_one_lwp (struct lwp_info
*lp
, int *signo_p
)
1370 int lwpid
= lp
->ptid
.lwp ();
1373 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1375 if (debug_linux_nat
&& lp
->status
)
1376 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1377 strsignal (WSTOPSIG (lp
->status
)),
1378 target_pid_to_str (lp
->ptid
));
1380 /* If there is a pending SIGSTOP, get rid of it. */
1383 if (debug_linux_nat
)
1384 fprintf_unfiltered (gdb_stdlog
,
1385 "DC: Sending SIGCONT to %s\n",
1386 target_pid_to_str (lp
->ptid
));
1388 kill_lwp (lwpid
, SIGCONT
);
1392 if (signo_p
== NULL
)
1394 /* Pass on any pending signal for this LWP. */
1395 signo
= get_detach_signal (lp
);
1400 /* Preparing to resume may try to write registers, and fail if the
1401 lwp is zombie. If that happens, ignore the error. We'll handle
1402 it below, when detach fails with ESRCH. */
1405 linux_target
->low_prepare_to_resume (lp
);
1407 CATCH (ex
, RETURN_MASK_ERROR
)
1409 if (!check_ptrace_stopped_lwp_gone (lp
))
1410 throw_exception (ex
);
1414 if (ptrace (PTRACE_DETACH
, lwpid
, 0, signo
) < 0)
1416 int save_errno
= errno
;
1418 /* We know the thread exists, so ESRCH must mean the lwp is
1419 zombie. This can happen if one of the already-detached
1420 threads exits the whole thread group. In that case we're
1421 still attached, and must reap the lwp. */
1422 if (save_errno
== ESRCH
)
1426 ret
= my_waitpid (lwpid
, &status
, __WALL
);
1429 warning (_("Couldn't reap LWP %d while detaching: %s"),
1430 lwpid
, strerror (errno
));
1432 else if (!WIFEXITED (status
) && !WIFSIGNALED (status
))
1434 warning (_("Reaping LWP %d while detaching "
1435 "returned unexpected status 0x%x"),
1441 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1442 safe_strerror (save_errno
));
1445 else if (debug_linux_nat
)
1447 fprintf_unfiltered (gdb_stdlog
,
1448 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1449 target_pid_to_str (lp
->ptid
),
1453 delete_lwp (lp
->ptid
);
1457 detach_callback (struct lwp_info
*lp
, void *data
)
1459 /* We don't actually detach from the thread group leader just yet.
1460 If the thread group exits, we must reap the zombie clone lwps
1461 before we're able to reap the leader. */
1462 if (lp
->ptid
.lwp () != lp
->ptid
.pid ())
1463 detach_one_lwp (lp
, NULL
);
1468 linux_nat_target::detach (inferior
*inf
, int from_tty
)
1470 struct lwp_info
*main_lwp
;
1473 /* Don't unregister from the event loop, as there may be other
1474 inferiors running. */
1476 /* Stop all threads before detaching. ptrace requires that the
1477 thread is stopped to sucessfully detach. */
1478 iterate_over_lwps (ptid_t (pid
), stop_callback
, NULL
);
1479 /* ... and wait until all of them have reported back that
1480 they're no longer running. */
1481 iterate_over_lwps (ptid_t (pid
), stop_wait_callback
, NULL
);
1483 iterate_over_lwps (ptid_t (pid
), detach_callback
, NULL
);
1485 /* Only the initial process should be left right now. */
1486 gdb_assert (num_lwps (pid
) == 1);
1488 main_lwp
= find_lwp_pid (ptid_t (pid
));
1490 if (forks_exist_p ())
1492 /* Multi-fork case. The current inferior_ptid is being detached
1493 from, but there are other viable forks to debug. Detach from
1494 the current fork, and context-switch to the first
1496 linux_fork_detach (from_tty
);
1500 target_announce_detach (from_tty
);
1502 /* Pass on any pending signal for the last LWP. */
1503 int signo
= get_detach_signal (main_lwp
);
1505 detach_one_lwp (main_lwp
, &signo
);
1507 detach_success (inf
);
1511 /* Resume execution of the inferior process. If STEP is nonzero,
1512 single-step it. If SIGNAL is nonzero, give it that signal. */
1515 linux_resume_one_lwp_throw (struct lwp_info
*lp
, int step
,
1516 enum gdb_signal signo
)
1520 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1521 We only presently need that if the LWP is stepped though (to
1522 handle the case of stepping a breakpoint instruction). */
1525 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
1527 lp
->stop_pc
= regcache_read_pc (regcache
);
1532 linux_target
->low_prepare_to_resume (lp
);
1533 linux_target
->low_resume (lp
->ptid
, step
, signo
);
1535 /* Successfully resumed. Clear state that no longer makes sense,
1536 and mark the LWP as running. Must not do this before resuming
1537 otherwise if that fails other code will be confused. E.g., we'd
1538 later try to stop the LWP and hang forever waiting for a stop
1539 status. Note that we must not throw after this is cleared,
1540 otherwise handle_zombie_lwp_error would get confused. */
1543 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1544 registers_changed_ptid (lp
->ptid
);
1547 /* Called when we try to resume a stopped LWP and that errors out. If
1548 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1549 or about to become), discard the error, clear any pending status
1550 the LWP may have, and return true (we'll collect the exit status
1551 soon enough). Otherwise, return false. */
1554 check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
)
1556 /* If we get an error after resuming the LWP successfully, we'd
1557 confuse !T state for the LWP being gone. */
1558 gdb_assert (lp
->stopped
);
1560 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1561 because even if ptrace failed with ESRCH, the tracee may be "not
1562 yet fully dead", but already refusing ptrace requests. In that
1563 case the tracee has 'R (Running)' state for a little bit
1564 (observed in Linux 3.18). See also the note on ESRCH in the
1565 ptrace(2) man page. Instead, check whether the LWP has any state
1566 other than ptrace-stopped. */
1568 /* Don't assume anything if /proc/PID/status can't be read. */
1569 if (linux_proc_pid_is_trace_stopped_nowarn (lp
->ptid
.lwp ()) == 0)
1571 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1573 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
1579 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1580 disappears while we try to resume it. */
1583 linux_resume_one_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1587 linux_resume_one_lwp_throw (lp
, step
, signo
);
1589 CATCH (ex
, RETURN_MASK_ERROR
)
1591 if (!check_ptrace_stopped_lwp_gone (lp
))
1592 throw_exception (ex
);
1600 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1604 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
1606 if (inf
->vfork_child
!= NULL
)
1608 if (debug_linux_nat
)
1609 fprintf_unfiltered (gdb_stdlog
,
1610 "RC: Not resuming %s (vfork parent)\n",
1611 target_pid_to_str (lp
->ptid
));
1613 else if (!lwp_status_pending_p (lp
))
1615 if (debug_linux_nat
)
1616 fprintf_unfiltered (gdb_stdlog
,
1617 "RC: Resuming sibling %s, %s, %s\n",
1618 target_pid_to_str (lp
->ptid
),
1619 (signo
!= GDB_SIGNAL_0
1620 ? strsignal (gdb_signal_to_host (signo
))
1622 step
? "step" : "resume");
1624 linux_resume_one_lwp (lp
, step
, signo
);
1628 if (debug_linux_nat
)
1629 fprintf_unfiltered (gdb_stdlog
,
1630 "RC: Not resuming sibling %s (has pending)\n",
1631 target_pid_to_str (lp
->ptid
));
1636 if (debug_linux_nat
)
1637 fprintf_unfiltered (gdb_stdlog
,
1638 "RC: Not resuming sibling %s (not stopped)\n",
1639 target_pid_to_str (lp
->ptid
));
1643 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1644 Resume LWP with the last stop signal, if it is in pass state. */
1647 linux_nat_resume_callback (struct lwp_info
*lp
, void *except
)
1649 enum gdb_signal signo
= GDB_SIGNAL_0
;
1656 struct thread_info
*thread
;
1658 thread
= find_thread_ptid (lp
->ptid
);
1661 signo
= thread
->suspend
.stop_signal
;
1662 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1666 resume_lwp (lp
, 0, signo
);
1671 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1674 lp
->last_resume_kind
= resume_stop
;
1679 resume_set_callback (struct lwp_info
*lp
, void *data
)
1682 lp
->last_resume_kind
= resume_continue
;
1687 linux_nat_target::resume (ptid_t ptid
, int step
, enum gdb_signal signo
)
1689 struct lwp_info
*lp
;
1692 if (debug_linux_nat
)
1693 fprintf_unfiltered (gdb_stdlog
,
1694 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1695 step
? "step" : "resume",
1696 target_pid_to_str (ptid
),
1697 (signo
!= GDB_SIGNAL_0
1698 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1699 target_pid_to_str (inferior_ptid
));
1701 /* A specific PTID means `step only this process id'. */
1702 resume_many
= (minus_one_ptid
== ptid
1705 /* Mark the lwps we're resuming as resumed. */
1706 iterate_over_lwps (ptid
, resume_set_callback
, NULL
);
1708 /* See if it's the current inferior that should be handled
1711 lp
= find_lwp_pid (inferior_ptid
);
1713 lp
= find_lwp_pid (ptid
);
1714 gdb_assert (lp
!= NULL
);
1716 /* Remember if we're stepping. */
1717 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1719 /* If we have a pending wait status for this thread, there is no
1720 point in resuming the process. But first make sure that
1721 linux_nat_wait won't preemptively handle the event - we
1722 should never take this short-circuit if we are going to
1723 leave LP running, since we have skipped resuming all the
1724 other threads. This bit of code needs to be synchronized
1725 with linux_nat_wait. */
1727 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1730 && WSTOPSIG (lp
->status
)
1731 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1733 if (debug_linux_nat
)
1734 fprintf_unfiltered (gdb_stdlog
,
1735 "LLR: Not short circuiting for ignored "
1736 "status 0x%x\n", lp
->status
);
1738 /* FIXME: What should we do if we are supposed to continue
1739 this thread with a signal? */
1740 gdb_assert (signo
== GDB_SIGNAL_0
);
1741 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1746 if (lwp_status_pending_p (lp
))
1748 /* FIXME: What should we do if we are supposed to continue
1749 this thread with a signal? */
1750 gdb_assert (signo
== GDB_SIGNAL_0
);
1752 if (debug_linux_nat
)
1753 fprintf_unfiltered (gdb_stdlog
,
1754 "LLR: Short circuiting for status 0x%x\n",
1757 if (target_can_async_p ())
1760 /* Tell the event loop we have something to process. */
1767 iterate_over_lwps (ptid
, linux_nat_resume_callback
, lp
);
1769 if (debug_linux_nat
)
1770 fprintf_unfiltered (gdb_stdlog
,
1771 "LLR: %s %s, %s (resume event thread)\n",
1772 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1773 target_pid_to_str (lp
->ptid
),
1774 (signo
!= GDB_SIGNAL_0
1775 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1777 linux_resume_one_lwp (lp
, step
, signo
);
1779 if (target_can_async_p ())
1783 /* Send a signal to an LWP. */
1786 kill_lwp (int lwpid
, int signo
)
1791 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1792 if (errno
== ENOSYS
)
1794 /* If tkill fails, then we are not using nptl threads, a
1795 configuration we no longer support. */
1796 perror_with_name (("tkill"));
1801 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1802 event, check if the core is interested in it: if not, ignore the
1803 event, and keep waiting; otherwise, we need to toggle the LWP's
1804 syscall entry/exit status, since the ptrace event itself doesn't
1805 indicate it, and report the trap to higher layers. */
1808 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1810 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1811 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1812 thread_info
*thread
= find_thread_ptid (lp
->ptid
);
1813 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, thread
);
1817 /* If we're stopping threads, there's a SIGSTOP pending, which
1818 makes it so that the LWP reports an immediate syscall return,
1819 followed by the SIGSTOP. Skip seeing that "return" using
1820 PTRACE_CONT directly, and let stop_wait_callback collect the
1821 SIGSTOP. Later when the thread is resumed, a new syscall
1822 entry event. If we didn't do this (and returned 0), we'd
1823 leave a syscall entry pending, and our caller, by using
1824 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1825 itself. Later, when the user re-resumes this LWP, we'd see
1826 another syscall entry event and we'd mistake it for a return.
1828 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1829 (leaving immediately with LWP->signalled set, without issuing
1830 a PTRACE_CONT), it would still be problematic to leave this
1831 syscall enter pending, as later when the thread is resumed,
1832 it would then see the same syscall exit mentioned above,
1833 followed by the delayed SIGSTOP, while the syscall didn't
1834 actually get to execute. It seems it would be even more
1835 confusing to the user. */
1837 if (debug_linux_nat
)
1838 fprintf_unfiltered (gdb_stdlog
,
1839 "LHST: ignoring syscall %d "
1840 "for LWP %ld (stopping threads), "
1841 "resuming with PTRACE_CONT for SIGSTOP\n",
1845 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1846 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
1851 /* Always update the entry/return state, even if this particular
1852 syscall isn't interesting to the core now. In async mode,
1853 the user could install a new catchpoint for this syscall
1854 between syscall enter/return, and we'll need to know to
1855 report a syscall return if that happens. */
1856 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1857 ? TARGET_WAITKIND_SYSCALL_RETURN
1858 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1860 if (catch_syscall_enabled ())
1862 if (catching_syscall_number (syscall_number
))
1864 /* Alright, an event to report. */
1865 ourstatus
->kind
= lp
->syscall_state
;
1866 ourstatus
->value
.syscall_number
= syscall_number
;
1868 if (debug_linux_nat
)
1869 fprintf_unfiltered (gdb_stdlog
,
1870 "LHST: stopping for %s of syscall %d"
1873 == TARGET_WAITKIND_SYSCALL_ENTRY
1874 ? "entry" : "return",
1880 if (debug_linux_nat
)
1881 fprintf_unfiltered (gdb_stdlog
,
1882 "LHST: ignoring %s of syscall %d "
1884 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1885 ? "entry" : "return",
1891 /* If we had been syscall tracing, and hence used PT_SYSCALL
1892 before on this LWP, it could happen that the user removes all
1893 syscall catchpoints before we get to process this event.
1894 There are two noteworthy issues here:
1896 - When stopped at a syscall entry event, resuming with
1897 PT_STEP still resumes executing the syscall and reports a
1900 - Only PT_SYSCALL catches syscall enters. If we last
1901 single-stepped this thread, then this event can't be a
1902 syscall enter. If we last single-stepped this thread, this
1903 has to be a syscall exit.
1905 The points above mean that the next resume, be it PT_STEP or
1906 PT_CONTINUE, can not trigger a syscall trace event. */
1907 if (debug_linux_nat
)
1908 fprintf_unfiltered (gdb_stdlog
,
1909 "LHST: caught syscall event "
1910 "with no syscall catchpoints."
1911 " %d for LWP %ld, ignoring\n",
1914 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1917 /* The core isn't interested in this event. For efficiency, avoid
1918 stopping all threads only to have the core resume them all again.
1919 Since we're not stopping threads, if we're still syscall tracing
1920 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1921 subsequent syscall. Simply resume using the inf-ptrace layer,
1922 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1924 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
1928 /* Handle a GNU/Linux extended wait response. If we see a clone
1929 event, we need to add the new LWP to our list (and not report the
1930 trap to higher layers). This function returns non-zero if the
1931 event should be ignored and we should wait again. If STOPPING is
1932 true, the new LWP remains stopped, otherwise it is continued. */
1935 linux_handle_extended_wait (struct lwp_info
*lp
, int status
)
1937 int pid
= lp
->ptid
.lwp ();
1938 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1939 int event
= linux_ptrace_get_extended_event (status
);
1941 /* All extended events we currently use are mid-syscall. Only
1942 PTRACE_EVENT_STOP is delivered more like a signal-stop, but
1943 you have to be using PTRACE_SEIZE to get that. */
1944 lp
->syscall_state
= TARGET_WAITKIND_SYSCALL_ENTRY
;
1946 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1947 || event
== PTRACE_EVENT_CLONE
)
1949 unsigned long new_pid
;
1952 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1954 /* If we haven't already seen the new PID stop, wait for it now. */
1955 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1957 /* The new child has a pending SIGSTOP. We can't affect it until it
1958 hits the SIGSTOP, but we're already attached. */
1959 ret
= my_waitpid (new_pid
, &status
, __WALL
);
1961 perror_with_name (_("waiting for new child"));
1962 else if (ret
!= new_pid
)
1963 internal_error (__FILE__
, __LINE__
,
1964 _("wait returned unexpected PID %d"), ret
);
1965 else if (!WIFSTOPPED (status
))
1966 internal_error (__FILE__
, __LINE__
,
1967 _("wait returned unexpected status 0x%x"), status
);
1970 ourstatus
->value
.related_pid
= ptid_t (new_pid
, new_pid
, 0);
1972 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
1974 /* The arch-specific native code may need to know about new
1975 forks even if those end up never mapped to an
1977 linux_target
->low_new_fork (lp
, new_pid
);
1980 if (event
== PTRACE_EVENT_FORK
1981 && linux_fork_checkpointing_p (lp
->ptid
.pid ()))
1983 /* Handle checkpointing by linux-fork.c here as a special
1984 case. We don't want the follow-fork-mode or 'catch fork'
1985 to interfere with this. */
1987 /* This won't actually modify the breakpoint list, but will
1988 physically remove the breakpoints from the child. */
1989 detach_breakpoints (ptid_t (new_pid
, new_pid
, 0));
1991 /* Retain child fork in ptrace (stopped) state. */
1992 if (!find_fork_pid (new_pid
))
1995 /* Report as spurious, so that infrun doesn't want to follow
1996 this fork. We're actually doing an infcall in
1998 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
2000 /* Report the stop to the core. */
2004 if (event
== PTRACE_EVENT_FORK
)
2005 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
2006 else if (event
== PTRACE_EVENT_VFORK
)
2007 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
2008 else if (event
== PTRACE_EVENT_CLONE
)
2010 struct lwp_info
*new_lp
;
2012 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2014 if (debug_linux_nat
)
2015 fprintf_unfiltered (gdb_stdlog
,
2016 "LHEW: Got clone event "
2017 "from LWP %d, new child is LWP %ld\n",
2020 new_lp
= add_lwp (ptid_t (lp
->ptid
.pid (), new_pid
, 0));
2021 new_lp
->stopped
= 1;
2022 new_lp
->resumed
= 1;
2024 /* If the thread_db layer is active, let it record the user
2025 level thread id and status, and add the thread to GDB's
2027 if (!thread_db_notice_clone (lp
->ptid
, new_lp
->ptid
))
2029 /* The process is not using thread_db. Add the LWP to
2031 target_post_attach (new_lp
->ptid
.lwp ());
2032 add_thread (new_lp
->ptid
);
2035 /* Even if we're stopping the thread for some reason
2036 internal to this module, from the perspective of infrun
2037 and the user/frontend, this new thread is running until
2038 it next reports a stop. */
2039 set_running (new_lp
->ptid
, 1);
2040 set_executing (new_lp
->ptid
, 1);
2042 if (WSTOPSIG (status
) != SIGSTOP
)
2044 /* This can happen if someone starts sending signals to
2045 the new thread before it gets a chance to run, which
2046 have a lower number than SIGSTOP (e.g. SIGUSR1).
2047 This is an unlikely case, and harder to handle for
2048 fork / vfork than for clone, so we do not try - but
2049 we handle it for clone events here. */
2051 new_lp
->signalled
= 1;
2053 /* We created NEW_LP so it cannot yet contain STATUS. */
2054 gdb_assert (new_lp
->status
== 0);
2056 /* Save the wait status to report later. */
2057 if (debug_linux_nat
)
2058 fprintf_unfiltered (gdb_stdlog
,
2059 "LHEW: waitpid of new LWP %ld, "
2060 "saving status %s\n",
2061 (long) new_lp
->ptid
.lwp (),
2062 status_to_str (status
));
2063 new_lp
->status
= status
;
2065 else if (report_thread_events
)
2067 new_lp
->waitstatus
.kind
= TARGET_WAITKIND_THREAD_CREATED
;
2068 new_lp
->status
= status
;
2077 if (event
== PTRACE_EVENT_EXEC
)
2079 if (debug_linux_nat
)
2080 fprintf_unfiltered (gdb_stdlog
,
2081 "LHEW: Got exec event from LWP %ld\n",
2084 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2085 ourstatus
->value
.execd_pathname
2086 = xstrdup (linux_proc_pid_to_exec_file (pid
));
2088 /* The thread that execed must have been resumed, but, when a
2089 thread execs, it changes its tid to the tgid, and the old
2090 tgid thread might have not been resumed. */
2095 if (event
== PTRACE_EVENT_VFORK_DONE
)
2097 if (current_inferior ()->waiting_for_vfork_done
)
2099 if (debug_linux_nat
)
2100 fprintf_unfiltered (gdb_stdlog
,
2101 "LHEW: Got expected PTRACE_EVENT_"
2102 "VFORK_DONE from LWP %ld: stopping\n",
2105 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2109 if (debug_linux_nat
)
2110 fprintf_unfiltered (gdb_stdlog
,
2111 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2112 "from LWP %ld: ignoring\n",
2117 internal_error (__FILE__
, __LINE__
,
2118 _("unknown ptrace event %d"), event
);
2121 /* Suspend waiting for a signal. We're mostly interested in
2127 if (debug_linux_nat
)
2128 fprintf_unfiltered (gdb_stdlog
, "linux-nat: about to sigsuspend\n");
2129 sigsuspend (&suspend_mask
);
2131 /* If the quit flag is set, it means that the user pressed Ctrl-C
2132 and we're debugging a process that is running on a separate
2133 terminal, so we must forward the Ctrl-C to the inferior. (If the
2134 inferior is sharing GDB's terminal, then the Ctrl-C reaches the
2135 inferior directly.) We must do this here because functions that
2136 need to block waiting for a signal loop forever until there's an
2137 event to report before returning back to the event loop. */
2138 if (!target_terminal::is_ours ())
2140 if (check_quit_flag ())
2141 target_pass_ctrlc ();
2145 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2149 wait_lwp (struct lwp_info
*lp
)
2153 int thread_dead
= 0;
2156 gdb_assert (!lp
->stopped
);
2157 gdb_assert (lp
->status
== 0);
2159 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2160 block_child_signals (&prev_mask
);
2164 pid
= my_waitpid (lp
->ptid
.lwp (), &status
, __WALL
| WNOHANG
);
2165 if (pid
== -1 && errno
== ECHILD
)
2167 /* The thread has previously exited. We need to delete it
2168 now because if this was a non-leader thread execing, we
2169 won't get an exit event. See comments on exec events at
2170 the top of the file. */
2172 if (debug_linux_nat
)
2173 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2174 target_pid_to_str (lp
->ptid
));
2179 /* Bugs 10970, 12702.
2180 Thread group leader may have exited in which case we'll lock up in
2181 waitpid if there are other threads, even if they are all zombies too.
2182 Basically, we're not supposed to use waitpid this way.
2183 tkill(pid,0) cannot be used here as it gets ESRCH for both
2184 for zombie and running processes.
2186 As a workaround, check if we're waiting for the thread group leader and
2187 if it's a zombie, and avoid calling waitpid if it is.
2189 This is racy, what if the tgl becomes a zombie right after we check?
2190 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2191 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2193 if (lp
->ptid
.pid () == lp
->ptid
.lwp ()
2194 && linux_proc_pid_is_zombie (lp
->ptid
.lwp ()))
2197 if (debug_linux_nat
)
2198 fprintf_unfiltered (gdb_stdlog
,
2199 "WL: Thread group leader %s vanished.\n",
2200 target_pid_to_str (lp
->ptid
));
2204 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2205 get invoked despite our caller had them intentionally blocked by
2206 block_child_signals. This is sensitive only to the loop of
2207 linux_nat_wait_1 and there if we get called my_waitpid gets called
2208 again before it gets to sigsuspend so we can safely let the handlers
2209 get executed here. */
2213 restore_child_signals_mask (&prev_mask
);
2217 gdb_assert (pid
== lp
->ptid
.lwp ());
2219 if (debug_linux_nat
)
2221 fprintf_unfiltered (gdb_stdlog
,
2222 "WL: waitpid %s received %s\n",
2223 target_pid_to_str (lp
->ptid
),
2224 status_to_str (status
));
2227 /* Check if the thread has exited. */
2228 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2230 if (report_thread_events
2231 || lp
->ptid
.pid () == lp
->ptid
.lwp ())
2233 if (debug_linux_nat
)
2234 fprintf_unfiltered (gdb_stdlog
, "WL: LWP %d exited.\n",
2237 /* If this is the leader exiting, it means the whole
2238 process is gone. Store the status to report to the
2239 core. Store it in lp->waitstatus, because lp->status
2240 would be ambiguous (W_EXITCODE(0,0) == 0). */
2241 store_waitstatus (&lp
->waitstatus
, status
);
2246 if (debug_linux_nat
)
2247 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2248 target_pid_to_str (lp
->ptid
));
2258 gdb_assert (WIFSTOPPED (status
));
2261 if (lp
->must_set_ptrace_flags
)
2263 struct inferior
*inf
= find_inferior_pid (lp
->ptid
.pid ());
2264 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2266 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2267 lp
->must_set_ptrace_flags
= 0;
2270 /* Handle GNU/Linux's syscall SIGTRAPs. */
2271 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2273 /* No longer need the sysgood bit. The ptrace event ends up
2274 recorded in lp->waitstatus if we care for it. We can carry
2275 on handling the event like a regular SIGTRAP from here
2277 status
= W_STOPCODE (SIGTRAP
);
2278 if (linux_handle_syscall_trap (lp
, 1))
2279 return wait_lwp (lp
);
2283 /* Almost all other ptrace-stops are known to be outside of system
2284 calls, with further exceptions in linux_handle_extended_wait. */
2285 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
2288 /* Handle GNU/Linux's extended waitstatus for trace events. */
2289 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2290 && linux_is_extended_waitstatus (status
))
2292 if (debug_linux_nat
)
2293 fprintf_unfiltered (gdb_stdlog
,
2294 "WL: Handling extended status 0x%06x\n",
2296 linux_handle_extended_wait (lp
, status
);
2303 /* Send a SIGSTOP to LP. */
2306 stop_callback (struct lwp_info
*lp
, void *data
)
2308 if (!lp
->stopped
&& !lp
->signalled
)
2312 if (debug_linux_nat
)
2314 fprintf_unfiltered (gdb_stdlog
,
2315 "SC: kill %s **<SIGSTOP>**\n",
2316 target_pid_to_str (lp
->ptid
));
2319 ret
= kill_lwp (lp
->ptid
.lwp (), SIGSTOP
);
2320 if (debug_linux_nat
)
2322 fprintf_unfiltered (gdb_stdlog
,
2323 "SC: lwp kill %d %s\n",
2325 errno
? safe_strerror (errno
) : "ERRNO-OK");
2329 gdb_assert (lp
->status
== 0);
2335 /* Request a stop on LWP. */
2338 linux_stop_lwp (struct lwp_info
*lwp
)
2340 stop_callback (lwp
, NULL
);
2343 /* See linux-nat.h */
2346 linux_stop_and_wait_all_lwps (void)
2348 /* Stop all LWP's ... */
2349 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
2351 /* ... and wait until all of them have reported back that
2352 they're no longer running. */
2353 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
2356 /* See linux-nat.h */
2359 linux_unstop_all_lwps (void)
2361 iterate_over_lwps (minus_one_ptid
,
2362 resume_stopped_resumed_lwps
, &minus_one_ptid
);
2365 /* Return non-zero if LWP PID has a pending SIGINT. */
2368 linux_nat_has_pending_sigint (int pid
)
2370 sigset_t pending
, blocked
, ignored
;
2372 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2374 if (sigismember (&pending
, SIGINT
)
2375 && !sigismember (&ignored
, SIGINT
))
2381 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2384 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2386 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2387 flag to consume the next one. */
2388 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2389 && WSTOPSIG (lp
->status
) == SIGINT
)
2392 lp
->ignore_sigint
= 1;
2397 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2398 This function is called after we know the LWP has stopped; if the LWP
2399 stopped before the expected SIGINT was delivered, then it will never have
2400 arrived. Also, if the signal was delivered to a shared queue and consumed
2401 by a different thread, it will never be delivered to this LWP. */
2404 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2406 if (!lp
->ignore_sigint
)
2409 if (!linux_nat_has_pending_sigint (lp
->ptid
.lwp ()))
2411 if (debug_linux_nat
)
2412 fprintf_unfiltered (gdb_stdlog
,
2413 "MCIS: Clearing bogus flag for %s\n",
2414 target_pid_to_str (lp
->ptid
));
2415 lp
->ignore_sigint
= 0;
2419 /* Fetch the possible triggered data watchpoint info and store it in
2422 On some archs, like x86, that use debug registers to set
2423 watchpoints, it's possible that the way to know which watched
2424 address trapped, is to check the register that is used to select
2425 which address to watch. Problem is, between setting the watchpoint
2426 and reading back which data address trapped, the user may change
2427 the set of watchpoints, and, as a consequence, GDB changes the
2428 debug registers in the inferior. To avoid reading back a stale
2429 stopped-data-address when that happens, we cache in LP the fact
2430 that a watchpoint trapped, and the corresponding data address, as
2431 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2432 registers meanwhile, we have the cached data we can rely on. */
2435 check_stopped_by_watchpoint (struct lwp_info
*lp
)
2437 scoped_restore save_inferior_ptid
= make_scoped_restore (&inferior_ptid
);
2438 inferior_ptid
= lp
->ptid
;
2440 if (linux_target
->low_stopped_by_watchpoint ())
2442 lp
->stop_reason
= TARGET_STOPPED_BY_WATCHPOINT
;
2443 lp
->stopped_data_address_p
2444 = linux_target
->low_stopped_data_address (&lp
->stopped_data_address
);
2447 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2450 /* Returns true if the LWP had stopped for a watchpoint. */
2453 linux_nat_target::stopped_by_watchpoint ()
2455 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2457 gdb_assert (lp
!= NULL
);
2459 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2463 linux_nat_target::stopped_data_address (CORE_ADDR
*addr_p
)
2465 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2467 gdb_assert (lp
!= NULL
);
2469 *addr_p
= lp
->stopped_data_address
;
2471 return lp
->stopped_data_address_p
;
2474 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2477 linux_nat_target::low_status_is_event (int status
)
2479 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2482 /* Wait until LP is stopped. */
2485 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2487 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
2489 /* If this is a vfork parent, bail out, it is not going to report
2490 any SIGSTOP until the vfork is done with. */
2491 if (inf
->vfork_child
!= NULL
)
2498 status
= wait_lwp (lp
);
2502 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2503 && WSTOPSIG (status
) == SIGINT
)
2505 lp
->ignore_sigint
= 0;
2508 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
2510 if (debug_linux_nat
)
2511 fprintf_unfiltered (gdb_stdlog
,
2512 "PTRACE_CONT %s, 0, 0 (%s) "
2513 "(discarding SIGINT)\n",
2514 target_pid_to_str (lp
->ptid
),
2515 errno
? safe_strerror (errno
) : "OK");
2517 return stop_wait_callback (lp
, NULL
);
2520 maybe_clear_ignore_sigint (lp
);
2522 if (WSTOPSIG (status
) != SIGSTOP
)
2524 /* The thread was stopped with a signal other than SIGSTOP. */
2526 if (debug_linux_nat
)
2527 fprintf_unfiltered (gdb_stdlog
,
2528 "SWC: Pending event %s in %s\n",
2529 status_to_str ((int) status
),
2530 target_pid_to_str (lp
->ptid
));
2532 /* Save the sigtrap event. */
2533 lp
->status
= status
;
2534 gdb_assert (lp
->signalled
);
2535 save_stop_reason (lp
);
2539 /* We caught the SIGSTOP that we intended to catch. */
2541 if (debug_linux_nat
)
2542 fprintf_unfiltered (gdb_stdlog
,
2543 "SWC: Expected SIGSTOP caught for %s.\n",
2544 target_pid_to_str (lp
->ptid
));
2548 /* If we are waiting for this stop so we can report the thread
2549 stopped then we need to record this status. Otherwise, we can
2550 now discard this stop event. */
2551 if (lp
->last_resume_kind
== resume_stop
)
2553 lp
->status
= status
;
2554 save_stop_reason (lp
);
2562 /* Return non-zero if LP has a wait status pending. Discard the
2563 pending event and resume the LWP if the event that originally
2564 caused the stop became uninteresting. */
2567 status_callback (struct lwp_info
*lp
, void *data
)
2569 /* Only report a pending wait status if we pretend that this has
2570 indeed been resumed. */
2574 if (!lwp_status_pending_p (lp
))
2577 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
2578 || lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2580 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2584 pc
= regcache_read_pc (regcache
);
2586 if (pc
!= lp
->stop_pc
)
2588 if (debug_linux_nat
)
2589 fprintf_unfiltered (gdb_stdlog
,
2590 "SC: PC of %s changed. was=%s, now=%s\n",
2591 target_pid_to_str (lp
->ptid
),
2592 paddress (target_gdbarch (), lp
->stop_pc
),
2593 paddress (target_gdbarch (), pc
));
2597 #if !USE_SIGTRAP_SIGINFO
2598 else if (!breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2600 if (debug_linux_nat
)
2601 fprintf_unfiltered (gdb_stdlog
,
2602 "SC: previous breakpoint of %s, at %s gone\n",
2603 target_pid_to_str (lp
->ptid
),
2604 paddress (target_gdbarch (), lp
->stop_pc
));
2612 if (debug_linux_nat
)
2613 fprintf_unfiltered (gdb_stdlog
,
2614 "SC: pending event of %s cancelled.\n",
2615 target_pid_to_str (lp
->ptid
));
2618 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2626 /* Count the LWP's that have had events. */
2629 count_events_callback (struct lwp_info
*lp
, void *data
)
2631 int *count
= (int *) data
;
2633 gdb_assert (count
!= NULL
);
2635 /* Select only resumed LWPs that have an event pending. */
2636 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2642 /* Select the LWP (if any) that is currently being single-stepped. */
2645 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2647 if (lp
->last_resume_kind
== resume_step
2654 /* Returns true if LP has a status pending. */
2657 lwp_status_pending_p (struct lwp_info
*lp
)
2659 /* We check for lp->waitstatus in addition to lp->status, because we
2660 can have pending process exits recorded in lp->status and
2661 W_EXITCODE(0,0) happens to be 0. */
2662 return lp
->status
!= 0 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
;
2665 /* Select the Nth LWP that has had an event. */
2668 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2670 int *selector
= (int *) data
;
2672 gdb_assert (selector
!= NULL
);
2674 /* Select only resumed LWPs that have an event pending. */
2675 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2676 if ((*selector
)-- == 0)
2682 /* Called when the LWP stopped for a signal/trap. If it stopped for a
2683 trap check what caused it (breakpoint, watchpoint, trace, etc.),
2684 and save the result in the LWP's stop_reason field. If it stopped
2685 for a breakpoint, decrement the PC if necessary on the lwp's
2689 save_stop_reason (struct lwp_info
*lp
)
2691 struct regcache
*regcache
;
2692 struct gdbarch
*gdbarch
;
2695 #if USE_SIGTRAP_SIGINFO
2699 gdb_assert (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
);
2700 gdb_assert (lp
->status
!= 0);
2702 if (!linux_target
->low_status_is_event (lp
->status
))
2705 regcache
= get_thread_regcache (lp
->ptid
);
2706 gdbarch
= regcache
->arch ();
2708 pc
= regcache_read_pc (regcache
);
2709 sw_bp_pc
= pc
- gdbarch_decr_pc_after_break (gdbarch
);
2711 #if USE_SIGTRAP_SIGINFO
2712 if (linux_nat_get_siginfo (lp
->ptid
, &siginfo
))
2714 if (siginfo
.si_signo
== SIGTRAP
)
2716 if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
)
2717 && GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2719 /* The si_code is ambiguous on this arch -- check debug
2721 if (!check_stopped_by_watchpoint (lp
))
2722 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2724 else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
))
2726 /* If we determine the LWP stopped for a SW breakpoint,
2727 trust it. Particularly don't check watchpoint
2728 registers, because at least on s390, we'd find
2729 stopped-by-watchpoint as long as there's a watchpoint
2731 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2733 else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2735 /* This can indicate either a hardware breakpoint or
2736 hardware watchpoint. Check debug registers. */
2737 if (!check_stopped_by_watchpoint (lp
))
2738 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2740 else if (siginfo
.si_code
== TRAP_TRACE
)
2742 if (debug_linux_nat
)
2743 fprintf_unfiltered (gdb_stdlog
,
2744 "CSBB: %s stopped by trace\n",
2745 target_pid_to_str (lp
->ptid
));
2747 /* We may have single stepped an instruction that
2748 triggered a watchpoint. In that case, on some
2749 architectures (such as x86), instead of TRAP_HWBKPT,
2750 si_code indicates TRAP_TRACE, and we need to check
2751 the debug registers separately. */
2752 check_stopped_by_watchpoint (lp
);
2757 if ((!lp
->step
|| lp
->stop_pc
== sw_bp_pc
)
2758 && software_breakpoint_inserted_here_p (regcache
->aspace (),
2761 /* The LWP was either continued, or stepped a software
2762 breakpoint instruction. */
2763 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2766 if (hardware_breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2767 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2769 if (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
)
2770 check_stopped_by_watchpoint (lp
);
2773 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
)
2775 if (debug_linux_nat
)
2776 fprintf_unfiltered (gdb_stdlog
,
2777 "CSBB: %s stopped by software breakpoint\n",
2778 target_pid_to_str (lp
->ptid
));
2780 /* Back up the PC if necessary. */
2782 regcache_write_pc (regcache
, sw_bp_pc
);
2784 /* Update this so we record the correct stop PC below. */
2787 else if (lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2789 if (debug_linux_nat
)
2790 fprintf_unfiltered (gdb_stdlog
,
2791 "CSBB: %s stopped by hardware breakpoint\n",
2792 target_pid_to_str (lp
->ptid
));
2794 else if (lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
)
2796 if (debug_linux_nat
)
2797 fprintf_unfiltered (gdb_stdlog
,
2798 "CSBB: %s stopped by hardware watchpoint\n",
2799 target_pid_to_str (lp
->ptid
));
2806 /* Returns true if the LWP had stopped for a software breakpoint. */
2809 linux_nat_target::stopped_by_sw_breakpoint ()
2811 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2813 gdb_assert (lp
!= NULL
);
2815 return lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
;
2818 /* Implement the supports_stopped_by_sw_breakpoint method. */
2821 linux_nat_target::supports_stopped_by_sw_breakpoint ()
2823 return USE_SIGTRAP_SIGINFO
;
2826 /* Returns true if the LWP had stopped for a hardware
2827 breakpoint/watchpoint. */
2830 linux_nat_target::stopped_by_hw_breakpoint ()
2832 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2834 gdb_assert (lp
!= NULL
);
2836 return lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
;
2839 /* Implement the supports_stopped_by_hw_breakpoint method. */
2842 linux_nat_target::supports_stopped_by_hw_breakpoint ()
2844 return USE_SIGTRAP_SIGINFO
;
2847 /* Select one LWP out of those that have events pending. */
2850 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2853 int random_selector
;
2854 struct lwp_info
*event_lp
= NULL
;
2856 /* Record the wait status for the original LWP. */
2857 (*orig_lp
)->status
= *status
;
2859 /* In all-stop, give preference to the LWP that is being
2860 single-stepped. There will be at most one, and it will be the
2861 LWP that the core is most interested in. If we didn't do this,
2862 then we'd have to handle pending step SIGTRAPs somehow in case
2863 the core later continues the previously-stepped thread, as
2864 otherwise we'd report the pending SIGTRAP then, and the core, not
2865 having stepped the thread, wouldn't understand what the trap was
2866 for, and therefore would report it to the user as a random
2868 if (!target_is_non_stop_p ())
2870 event_lp
= iterate_over_lwps (filter
,
2871 select_singlestep_lwp_callback
, NULL
);
2872 if (event_lp
!= NULL
)
2874 if (debug_linux_nat
)
2875 fprintf_unfiltered (gdb_stdlog
,
2876 "SEL: Select single-step %s\n",
2877 target_pid_to_str (event_lp
->ptid
));
2881 if (event_lp
== NULL
)
2883 /* Pick one at random, out of those which have had events. */
2885 /* First see how many events we have. */
2886 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2887 gdb_assert (num_events
> 0);
2889 /* Now randomly pick a LWP out of those that have had
2891 random_selector
= (int)
2892 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2894 if (debug_linux_nat
&& num_events
> 1)
2895 fprintf_unfiltered (gdb_stdlog
,
2896 "SEL: Found %d events, selecting #%d\n",
2897 num_events
, random_selector
);
2899 event_lp
= iterate_over_lwps (filter
,
2900 select_event_lwp_callback
,
2904 if (event_lp
!= NULL
)
2906 /* Switch the event LWP. */
2907 *orig_lp
= event_lp
;
2908 *status
= event_lp
->status
;
2911 /* Flush the wait status for the event LWP. */
2912 (*orig_lp
)->status
= 0;
2915 /* Return non-zero if LP has been resumed. */
2918 resumed_callback (struct lwp_info
*lp
, void *data
)
2923 /* Check if we should go on and pass this event to common code.
2924 Return the affected lwp if we are, or NULL otherwise. */
2926 static struct lwp_info
*
2927 linux_nat_filter_event (int lwpid
, int status
)
2929 struct lwp_info
*lp
;
2930 int event
= linux_ptrace_get_extended_event (status
);
2932 lp
= find_lwp_pid (ptid_t (lwpid
));
2934 /* Check for stop events reported by a process we didn't already
2935 know about - anything not already in our LWP list.
2937 If we're expecting to receive stopped processes after
2938 fork, vfork, and clone events, then we'll just add the
2939 new one to our list and go back to waiting for the event
2940 to be reported - the stopped process might be returned
2941 from waitpid before or after the event is.
2943 But note the case of a non-leader thread exec'ing after the
2944 leader having exited, and gone from our lists. The non-leader
2945 thread changes its tid to the tgid. */
2947 if (WIFSTOPPED (status
) && lp
== NULL
2948 && (WSTOPSIG (status
) == SIGTRAP
&& event
== PTRACE_EVENT_EXEC
))
2950 /* A multi-thread exec after we had seen the leader exiting. */
2951 if (debug_linux_nat
)
2952 fprintf_unfiltered (gdb_stdlog
,
2953 "LLW: Re-adding thread group leader LWP %d.\n",
2956 lp
= add_lwp (ptid_t (lwpid
, lwpid
, 0));
2959 add_thread (lp
->ptid
);
2962 if (WIFSTOPPED (status
) && !lp
)
2964 if (debug_linux_nat
)
2965 fprintf_unfiltered (gdb_stdlog
,
2966 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2967 (long) lwpid
, status_to_str (status
));
2968 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2972 /* Make sure we don't report an event for the exit of an LWP not in
2973 our list, i.e. not part of the current process. This can happen
2974 if we detach from a program we originally forked and then it
2976 if (!WIFSTOPPED (status
) && !lp
)
2979 /* This LWP is stopped now. (And if dead, this prevents it from
2980 ever being continued.) */
2983 if (WIFSTOPPED (status
) && lp
->must_set_ptrace_flags
)
2985 struct inferior
*inf
= find_inferior_pid (lp
->ptid
.pid ());
2986 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2988 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2989 lp
->must_set_ptrace_flags
= 0;
2992 /* Handle GNU/Linux's syscall SIGTRAPs. */
2993 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2995 /* No longer need the sysgood bit. The ptrace event ends up
2996 recorded in lp->waitstatus if we care for it. We can carry
2997 on handling the event like a regular SIGTRAP from here
2999 status
= W_STOPCODE (SIGTRAP
);
3000 if (linux_handle_syscall_trap (lp
, 0))
3005 /* Almost all other ptrace-stops are known to be outside of system
3006 calls, with further exceptions in linux_handle_extended_wait. */
3007 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
3010 /* Handle GNU/Linux's extended waitstatus for trace events. */
3011 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
3012 && linux_is_extended_waitstatus (status
))
3014 if (debug_linux_nat
)
3015 fprintf_unfiltered (gdb_stdlog
,
3016 "LLW: Handling extended status 0x%06x\n",
3018 if (linux_handle_extended_wait (lp
, status
))
3022 /* Check if the thread has exited. */
3023 if (WIFEXITED (status
) || WIFSIGNALED (status
))
3025 if (!report_thread_events
3026 && num_lwps (lp
->ptid
.pid ()) > 1)
3028 if (debug_linux_nat
)
3029 fprintf_unfiltered (gdb_stdlog
,
3030 "LLW: %s exited.\n",
3031 target_pid_to_str (lp
->ptid
));
3033 /* If there is at least one more LWP, then the exit signal
3034 was not the end of the debugged application and should be
3040 /* Note that even if the leader was ptrace-stopped, it can still
3041 exit, if e.g., some other thread brings down the whole
3042 process (calls `exit'). So don't assert that the lwp is
3044 if (debug_linux_nat
)
3045 fprintf_unfiltered (gdb_stdlog
,
3046 "LWP %ld exited (resumed=%d)\n",
3047 lp
->ptid
.lwp (), lp
->resumed
);
3049 /* Dead LWP's aren't expected to reported a pending sigstop. */
3052 /* Store the pending event in the waitstatus, because
3053 W_EXITCODE(0,0) == 0. */
3054 store_waitstatus (&lp
->waitstatus
, status
);
3058 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3059 an attempt to stop an LWP. */
3061 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3065 if (lp
->last_resume_kind
== resume_stop
)
3067 if (debug_linux_nat
)
3068 fprintf_unfiltered (gdb_stdlog
,
3069 "LLW: resume_stop SIGSTOP caught for %s.\n",
3070 target_pid_to_str (lp
->ptid
));
3074 /* This is a delayed SIGSTOP. Filter out the event. */
3076 if (debug_linux_nat
)
3077 fprintf_unfiltered (gdb_stdlog
,
3078 "LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
3080 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3081 target_pid_to_str (lp
->ptid
));
3083 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3084 gdb_assert (lp
->resumed
);
3089 /* Make sure we don't report a SIGINT that we have already displayed
3090 for another thread. */
3091 if (lp
->ignore_sigint
3092 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3094 if (debug_linux_nat
)
3095 fprintf_unfiltered (gdb_stdlog
,
3096 "LLW: Delayed SIGINT caught for %s.\n",
3097 target_pid_to_str (lp
->ptid
));
3099 /* This is a delayed SIGINT. */
3100 lp
->ignore_sigint
= 0;
3102 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3103 if (debug_linux_nat
)
3104 fprintf_unfiltered (gdb_stdlog
,
3105 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3107 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3108 target_pid_to_str (lp
->ptid
));
3109 gdb_assert (lp
->resumed
);
3111 /* Discard the event. */
3115 /* Don't report signals that GDB isn't interested in, such as
3116 signals that are neither printed nor stopped upon. Stopping all
3117 threads can be a bit time-consuming so if we want decent
3118 performance with heavily multi-threaded programs, especially when
3119 they're using a high frequency timer, we'd better avoid it if we
3121 if (WIFSTOPPED (status
))
3123 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3125 if (!target_is_non_stop_p ())
3127 /* Only do the below in all-stop, as we currently use SIGSTOP
3128 to implement target_stop (see linux_nat_stop) in
3130 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3132 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3133 forwarded to the entire process group, that is, all LWPs
3134 will receive it - unless they're using CLONE_THREAD to
3135 share signals. Since we only want to report it once, we
3136 mark it as ignored for all LWPs except this one. */
3137 iterate_over_lwps (ptid_t (lp
->ptid
.pid ()),
3138 set_ignore_sigint
, NULL
);
3139 lp
->ignore_sigint
= 0;
3142 maybe_clear_ignore_sigint (lp
);
3145 /* When using hardware single-step, we need to report every signal.
3146 Otherwise, signals in pass_mask may be short-circuited
3147 except signals that might be caused by a breakpoint. */
3149 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
))
3150 && !linux_wstatus_maybe_breakpoint (status
))
3152 linux_resume_one_lwp (lp
, lp
->step
, signo
);
3153 if (debug_linux_nat
)
3154 fprintf_unfiltered (gdb_stdlog
,
3155 "LLW: %s %s, %s (preempt 'handle')\n",
3157 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3158 target_pid_to_str (lp
->ptid
),
3159 (signo
!= GDB_SIGNAL_0
3160 ? strsignal (gdb_signal_to_host (signo
))
3166 /* An interesting event. */
3168 lp
->status
= status
;
3169 save_stop_reason (lp
);
3173 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3174 their exits until all other threads in the group have exited. */
3177 check_zombie_leaders (void)
3179 for (inferior
*inf
: all_inferiors ())
3181 struct lwp_info
*leader_lp
;
3186 leader_lp
= find_lwp_pid (ptid_t (inf
->pid
));
3187 if (leader_lp
!= NULL
3188 /* Check if there are other threads in the group, as we may
3189 have raced with the inferior simply exiting. */
3190 && num_lwps (inf
->pid
) > 1
3191 && linux_proc_pid_is_zombie (inf
->pid
))
3193 if (debug_linux_nat
)
3194 fprintf_unfiltered (gdb_stdlog
,
3195 "CZL: Thread group leader %d zombie "
3196 "(it exited, or another thread execd).\n",
3199 /* A leader zombie can mean one of two things:
3201 - It exited, and there's an exit status pending
3202 available, or only the leader exited (not the whole
3203 program). In the latter case, we can't waitpid the
3204 leader's exit status until all other threads are gone.
3206 - There are 3 or more threads in the group, and a thread
3207 other than the leader exec'd. See comments on exec
3208 events at the top of the file. We could try
3209 distinguishing the exit and exec cases, by waiting once
3210 more, and seeing if something comes out, but it doesn't
3211 sound useful. The previous leader _does_ go away, and
3212 we'll re-add the new one once we see the exec event
3213 (which is just the same as what would happen if the
3214 previous leader did exit voluntarily before some other
3217 if (debug_linux_nat
)
3218 fprintf_unfiltered (gdb_stdlog
,
3219 "CZL: Thread group leader %d vanished.\n",
3221 exit_lwp (leader_lp
);
3226 /* Convenience function that is called when the kernel reports an exit
3227 event. This decides whether to report the event to GDB as a
3228 process exit event, a thread exit event, or to suppress the
3232 filter_exit_event (struct lwp_info
*event_child
,
3233 struct target_waitstatus
*ourstatus
)
3235 ptid_t ptid
= event_child
->ptid
;
3237 if (num_lwps (ptid
.pid ()) > 1)
3239 if (report_thread_events
)
3240 ourstatus
->kind
= TARGET_WAITKIND_THREAD_EXITED
;
3242 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3244 exit_lwp (event_child
);
3251 linux_nat_wait_1 (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3255 enum resume_kind last_resume_kind
;
3256 struct lwp_info
*lp
;
3259 if (debug_linux_nat
)
3260 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3262 /* The first time we get here after starting a new inferior, we may
3263 not have added it to the LWP list yet - this is the earliest
3264 moment at which we know its PID. */
3265 if (inferior_ptid
.is_pid ())
3267 /* Upgrade the main thread's ptid. */
3268 thread_change_ptid (inferior_ptid
,
3269 ptid_t (inferior_ptid
.pid (),
3270 inferior_ptid
.pid (), 0));
3272 lp
= add_initial_lwp (inferior_ptid
);
3276 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3277 block_child_signals (&prev_mask
);
3279 /* First check if there is a LWP with a wait status pending. */
3280 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3283 if (debug_linux_nat
)
3284 fprintf_unfiltered (gdb_stdlog
,
3285 "LLW: Using pending wait status %s for %s.\n",
3286 status_to_str (lp
->status
),
3287 target_pid_to_str (lp
->ptid
));
3290 /* But if we don't find a pending event, we'll have to wait. Always
3291 pull all events out of the kernel. We'll randomly select an
3292 event LWP out of all that have events, to prevent starvation. */
3298 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3301 - If the thread group leader exits while other threads in the
3302 thread group still exist, waitpid(TGID, ...) hangs. That
3303 waitpid won't return an exit status until the other threads
3304 in the group are reapped.
3306 - When a non-leader thread execs, that thread just vanishes
3307 without reporting an exit (so we'd hang if we waited for it
3308 explicitly in that case). The exec event is reported to
3312 lwpid
= my_waitpid (-1, &status
, __WALL
| WNOHANG
);
3314 if (debug_linux_nat
)
3315 fprintf_unfiltered (gdb_stdlog
,
3316 "LNW: waitpid(-1, ...) returned %d, %s\n",
3317 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3321 if (debug_linux_nat
)
3323 fprintf_unfiltered (gdb_stdlog
,
3324 "LLW: waitpid %ld received %s\n",
3325 (long) lwpid
, status_to_str (status
));
3328 linux_nat_filter_event (lwpid
, status
);
3329 /* Retry until nothing comes out of waitpid. A single
3330 SIGCHLD can indicate more than one child stopped. */
3334 /* Now that we've pulled all events out of the kernel, resume
3335 LWPs that don't have an interesting event to report. */
3336 iterate_over_lwps (minus_one_ptid
,
3337 resume_stopped_resumed_lwps
, &minus_one_ptid
);
3339 /* ... and find an LWP with a status to report to the core, if
3341 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3345 /* Check for zombie thread group leaders. Those can't be reaped
3346 until all other threads in the thread group are. */
3347 check_zombie_leaders ();
3349 /* If there are no resumed children left, bail. We'd be stuck
3350 forever in the sigsuspend call below otherwise. */
3351 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3353 if (debug_linux_nat
)
3354 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3356 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3358 restore_child_signals_mask (&prev_mask
);
3359 return minus_one_ptid
;
3362 /* No interesting event to report to the core. */
3364 if (target_options
& TARGET_WNOHANG
)
3366 if (debug_linux_nat
)
3367 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3369 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3370 restore_child_signals_mask (&prev_mask
);
3371 return minus_one_ptid
;
3374 /* We shouldn't end up here unless we want to try again. */
3375 gdb_assert (lp
== NULL
);
3377 /* Block until we get an event reported with SIGCHLD. */
3383 status
= lp
->status
;
3386 if (!target_is_non_stop_p ())
3388 /* Now stop all other LWP's ... */
3389 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3391 /* ... and wait until all of them have reported back that
3392 they're no longer running. */
3393 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3396 /* If we're not waiting for a specific LWP, choose an event LWP from
3397 among those that have had events. Giving equal priority to all
3398 LWPs that have had events helps prevent starvation. */
3399 if (ptid
== minus_one_ptid
|| ptid
.is_pid ())
3400 select_event_lwp (ptid
, &lp
, &status
);
3402 gdb_assert (lp
!= NULL
);
3404 /* Now that we've selected our final event LWP, un-adjust its PC if
3405 it was a software breakpoint, and we can't reliably support the
3406 "stopped by software breakpoint" stop reason. */
3407 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
3408 && !USE_SIGTRAP_SIGINFO
)
3410 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3411 struct gdbarch
*gdbarch
= regcache
->arch ();
3412 int decr_pc
= gdbarch_decr_pc_after_break (gdbarch
);
3418 pc
= regcache_read_pc (regcache
);
3419 regcache_write_pc (regcache
, pc
+ decr_pc
);
3423 /* We'll need this to determine whether to report a SIGSTOP as
3424 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3426 last_resume_kind
= lp
->last_resume_kind
;
3428 if (!target_is_non_stop_p ())
3430 /* In all-stop, from the core's perspective, all LWPs are now
3431 stopped until a new resume action is sent over. */
3432 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3436 resume_clear_callback (lp
, NULL
);
3439 if (linux_target
->low_status_is_event (status
))
3441 if (debug_linux_nat
)
3442 fprintf_unfiltered (gdb_stdlog
,
3443 "LLW: trap ptid is %s.\n",
3444 target_pid_to_str (lp
->ptid
));
3447 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3449 *ourstatus
= lp
->waitstatus
;
3450 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3453 store_waitstatus (ourstatus
, status
);
3455 if (debug_linux_nat
)
3456 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3458 restore_child_signals_mask (&prev_mask
);
3460 if (last_resume_kind
== resume_stop
3461 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3462 && WSTOPSIG (status
) == SIGSTOP
)
3464 /* A thread that has been requested to stop by GDB with
3465 target_stop, and it stopped cleanly, so report as SIG0. The
3466 use of SIGSTOP is an implementation detail. */
3467 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3470 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3471 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3474 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3476 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
)
3477 return filter_exit_event (lp
, ourstatus
);
3482 /* Resume LWPs that are currently stopped without any pending status
3483 to report, but are resumed from the core's perspective. */
3486 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3488 ptid_t
*wait_ptid_p
= (ptid_t
*) data
;
3492 if (debug_linux_nat
)
3493 fprintf_unfiltered (gdb_stdlog
,
3494 "RSRL: NOT resuming LWP %s, not stopped\n",
3495 target_pid_to_str (lp
->ptid
));
3497 else if (!lp
->resumed
)
3499 if (debug_linux_nat
)
3500 fprintf_unfiltered (gdb_stdlog
,
3501 "RSRL: NOT resuming LWP %s, not resumed\n",
3502 target_pid_to_str (lp
->ptid
));
3504 else if (lwp_status_pending_p (lp
))
3506 if (debug_linux_nat
)
3507 fprintf_unfiltered (gdb_stdlog
,
3508 "RSRL: NOT resuming LWP %s, has pending status\n",
3509 target_pid_to_str (lp
->ptid
));
3513 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3514 struct gdbarch
*gdbarch
= regcache
->arch ();
3518 CORE_ADDR pc
= regcache_read_pc (regcache
);
3519 int leave_stopped
= 0;
3521 /* Don't bother if there's a breakpoint at PC that we'd hit
3522 immediately, and we're not waiting for this LWP. */
3523 if (!lp
->ptid
.matches (*wait_ptid_p
))
3525 if (breakpoint_inserted_here_p (regcache
->aspace (), pc
))
3531 if (debug_linux_nat
)
3532 fprintf_unfiltered (gdb_stdlog
,
3533 "RSRL: resuming stopped-resumed LWP %s at "
3535 target_pid_to_str (lp
->ptid
),
3536 paddress (gdbarch
, pc
),
3539 linux_resume_one_lwp_throw (lp
, lp
->step
, GDB_SIGNAL_0
);
3542 CATCH (ex
, RETURN_MASK_ERROR
)
3544 if (!check_ptrace_stopped_lwp_gone (lp
))
3545 throw_exception (ex
);
3554 linux_nat_target::wait (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3559 if (debug_linux_nat
)
3561 std::string options_string
= target_options_to_string (target_options
);
3562 fprintf_unfiltered (gdb_stdlog
,
3563 "linux_nat_wait: [%s], [%s]\n",
3564 target_pid_to_str (ptid
),
3565 options_string
.c_str ());
3568 /* Flush the async file first. */
3569 if (target_is_async_p ())
3570 async_file_flush ();
3572 /* Resume LWPs that are currently stopped without any pending status
3573 to report, but are resumed from the core's perspective. LWPs get
3574 in this state if we find them stopping at a time we're not
3575 interested in reporting the event (target_wait on a
3576 specific_process, for example, see linux_nat_wait_1), and
3577 meanwhile the event became uninteresting. Don't bother resuming
3578 LWPs we're not going to wait for if they'd stop immediately. */
3579 if (target_is_non_stop_p ())
3580 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3582 event_ptid
= linux_nat_wait_1 (ptid
, ourstatus
, target_options
);
3584 /* If we requested any event, and something came out, assume there
3585 may be more. If we requested a specific lwp or process, also
3586 assume there may be more. */
3587 if (target_is_async_p ()
3588 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3589 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3590 || ptid
!= minus_one_ptid
))
3599 kill_one_lwp (pid_t pid
)
3601 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3604 kill_lwp (pid
, SIGKILL
);
3605 if (debug_linux_nat
)
3607 int save_errno
= errno
;
3609 fprintf_unfiltered (gdb_stdlog
,
3610 "KC: kill (SIGKILL) %ld, 0, 0 (%s)\n", (long) pid
,
3611 save_errno
? safe_strerror (save_errno
) : "OK");
3614 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3617 ptrace (PTRACE_KILL
, pid
, 0, 0);
3618 if (debug_linux_nat
)
3620 int save_errno
= errno
;
3622 fprintf_unfiltered (gdb_stdlog
,
3623 "KC: PTRACE_KILL %ld, 0, 0 (%s)\n", (long) pid
,
3624 save_errno
? safe_strerror (save_errno
) : "OK");
3628 /* Wait for an LWP to die. */
3631 kill_wait_one_lwp (pid_t pid
)
3635 /* We must make sure that there are no pending events (delayed
3636 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3637 program doesn't interfere with any following debugging session. */
3641 res
= my_waitpid (pid
, NULL
, __WALL
);
3642 if (res
!= (pid_t
) -1)
3644 if (debug_linux_nat
)
3645 fprintf_unfiltered (gdb_stdlog
,
3646 "KWC: wait %ld received unknown.\n",
3648 /* The Linux kernel sometimes fails to kill a thread
3649 completely after PTRACE_KILL; that goes from the stop
3650 point in do_fork out to the one in get_signal_to_deliver
3651 and waits again. So kill it again. */
3657 gdb_assert (res
== -1 && errno
== ECHILD
);
3660 /* Callback for iterate_over_lwps. */
3663 kill_callback (struct lwp_info
*lp
, void *data
)
3665 kill_one_lwp (lp
->ptid
.lwp ());
3669 /* Callback for iterate_over_lwps. */
3672 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3674 kill_wait_one_lwp (lp
->ptid
.lwp ());
3678 /* Kill the fork children of any threads of inferior INF that are
3679 stopped at a fork event. */
3682 kill_unfollowed_fork_children (struct inferior
*inf
)
3684 for (thread_info
*thread
: inf
->non_exited_threads ())
3686 struct target_waitstatus
*ws
= &thread
->pending_follow
;
3688 if (ws
->kind
== TARGET_WAITKIND_FORKED
3689 || ws
->kind
== TARGET_WAITKIND_VFORKED
)
3691 ptid_t child_ptid
= ws
->value
.related_pid
;
3692 int child_pid
= child_ptid
.pid ();
3693 int child_lwp
= child_ptid
.lwp ();
3695 kill_one_lwp (child_lwp
);
3696 kill_wait_one_lwp (child_lwp
);
3698 /* Let the arch-specific native code know this process is
3700 linux_target
->low_forget_process (child_pid
);
3706 linux_nat_target::kill ()
3708 /* If we're stopped while forking and we haven't followed yet,
3709 kill the other task. We need to do this first because the
3710 parent will be sleeping if this is a vfork. */
3711 kill_unfollowed_fork_children (current_inferior ());
3713 if (forks_exist_p ())
3714 linux_fork_killall ();
3717 ptid_t ptid
= ptid_t (inferior_ptid
.pid ());
3719 /* Stop all threads before killing them, since ptrace requires
3720 that the thread is stopped to sucessfully PTRACE_KILL. */
3721 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3722 /* ... and wait until all of them have reported back that
3723 they're no longer running. */
3724 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3726 /* Kill all LWP's ... */
3727 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3729 /* ... and wait until we've flushed all events. */
3730 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3733 target_mourn_inferior (inferior_ptid
);
3737 linux_nat_target::mourn_inferior ()
3739 int pid
= inferior_ptid
.pid ();
3741 purge_lwp_list (pid
);
3743 if (! forks_exist_p ())
3744 /* Normal case, no other forks available. */
3745 inf_ptrace_target::mourn_inferior ();
3747 /* Multi-fork case. The current inferior_ptid has exited, but
3748 there are other viable forks to debug. Delete the exiting
3749 one and context-switch to the first available. */
3750 linux_fork_mourn_inferior ();
3752 /* Let the arch-specific native code know this process is gone. */
3753 linux_target
->low_forget_process (pid
);
3756 /* Convert a native/host siginfo object, into/from the siginfo in the
3757 layout of the inferiors' architecture. */
3760 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3762 /* If the low target didn't do anything, then just do a straight
3764 if (!linux_target
->low_siginfo_fixup (siginfo
, inf_siginfo
, direction
))
3767 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3769 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3773 static enum target_xfer_status
3774 linux_xfer_siginfo (enum target_object object
,
3775 const char *annex
, gdb_byte
*readbuf
,
3776 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3777 ULONGEST
*xfered_len
)
3781 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3783 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3784 gdb_assert (readbuf
|| writebuf
);
3786 pid
= inferior_ptid
.lwp ();
3788 pid
= inferior_ptid
.pid ();
3790 if (offset
> sizeof (siginfo
))
3791 return TARGET_XFER_E_IO
;
3794 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3796 return TARGET_XFER_E_IO
;
3798 /* When GDB is built as a 64-bit application, ptrace writes into
3799 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3800 inferior with a 64-bit GDB should look the same as debugging it
3801 with a 32-bit GDB, we need to convert it. GDB core always sees
3802 the converted layout, so any read/write will have to be done
3804 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3806 if (offset
+ len
> sizeof (siginfo
))
3807 len
= sizeof (siginfo
) - offset
;
3809 if (readbuf
!= NULL
)
3810 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3813 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3815 /* Convert back to ptrace layout before flushing it out. */
3816 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3819 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3821 return TARGET_XFER_E_IO
;
3825 return TARGET_XFER_OK
;
3828 static enum target_xfer_status
3829 linux_nat_xfer_osdata (enum target_object object
,
3830 const char *annex
, gdb_byte
*readbuf
,
3831 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3832 ULONGEST
*xfered_len
);
3834 static enum target_xfer_status
3835 linux_proc_xfer_spu (enum target_object object
,
3836 const char *annex
, gdb_byte
*readbuf
,
3837 const gdb_byte
*writebuf
,
3838 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
);
3840 static enum target_xfer_status
3841 linux_proc_xfer_partial (enum target_object object
,
3842 const char *annex
, gdb_byte
*readbuf
,
3843 const gdb_byte
*writebuf
,
3844 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
);
3846 enum target_xfer_status
3847 linux_nat_target::xfer_partial (enum target_object object
,
3848 const char *annex
, gdb_byte
*readbuf
,
3849 const gdb_byte
*writebuf
,
3850 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3852 enum target_xfer_status xfer
;
3854 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3855 return linux_xfer_siginfo (object
, annex
, readbuf
, writebuf
,
3856 offset
, len
, xfered_len
);
3858 /* The target is connected but no live inferior is selected. Pass
3859 this request down to a lower stratum (e.g., the executable
3861 if (object
== TARGET_OBJECT_MEMORY
&& inferior_ptid
== null_ptid
)
3862 return TARGET_XFER_EOF
;
3864 if (object
== TARGET_OBJECT_AUXV
)
3865 return memory_xfer_auxv (this, object
, annex
, readbuf
, writebuf
,
3866 offset
, len
, xfered_len
);
3868 if (object
== TARGET_OBJECT_OSDATA
)
3869 return linux_nat_xfer_osdata (object
, annex
, readbuf
, writebuf
,
3870 offset
, len
, xfered_len
);
3872 if (object
== TARGET_OBJECT_SPU
)
3873 return linux_proc_xfer_spu (object
, annex
, readbuf
, writebuf
,
3874 offset
, len
, xfered_len
);
3876 /* GDB calculates all addresses in the largest possible address
3878 The address width must be masked before its final use - either by
3879 linux_proc_xfer_partial or inf_ptrace_target::xfer_partial.
3881 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
3883 if (object
== TARGET_OBJECT_MEMORY
)
3885 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
3887 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
3888 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
3891 xfer
= linux_proc_xfer_partial (object
, annex
, readbuf
, writebuf
,
3892 offset
, len
, xfered_len
);
3893 if (xfer
!= TARGET_XFER_EOF
)
3896 return inf_ptrace_target::xfer_partial (object
, annex
, readbuf
, writebuf
,
3897 offset
, len
, xfered_len
);
3901 linux_nat_target::thread_alive (ptid_t ptid
)
3903 /* As long as a PTID is in lwp list, consider it alive. */
3904 return find_lwp_pid (ptid
) != NULL
;
3907 /* Implement the to_update_thread_list target method for this
3911 linux_nat_target::update_thread_list ()
3913 struct lwp_info
*lwp
;
3915 /* We add/delete threads from the list as clone/exit events are
3916 processed, so just try deleting exited threads still in the
3918 delete_exited_threads ();
3920 /* Update the processor core that each lwp/thread was last seen
3924 /* Avoid accessing /proc if the thread hasn't run since we last
3925 time we fetched the thread's core. Accessing /proc becomes
3926 noticeably expensive when we have thousands of LWPs. */
3927 if (lwp
->core
== -1)
3928 lwp
->core
= linux_common_core_of_thread (lwp
->ptid
);
3933 linux_nat_target::pid_to_str (ptid_t ptid
)
3935 static char buf
[64];
3938 && (ptid
.pid () != ptid
.lwp ()
3939 || num_lwps (ptid
.pid ()) > 1))
3941 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid
.lwp ());
3945 return normal_pid_to_str (ptid
);
3949 linux_nat_target::thread_name (struct thread_info
*thr
)
3951 return linux_proc_tid_get_name (thr
->ptid
);
3954 /* Accepts an integer PID; Returns a string representing a file that
3955 can be opened to get the symbols for the child process. */
3958 linux_nat_target::pid_to_exec_file (int pid
)
3960 return linux_proc_pid_to_exec_file (pid
);
3963 /* Implement the to_xfer_partial target method using /proc/<pid>/mem.
3964 Because we can use a single read/write call, this can be much more
3965 efficient than banging away at PTRACE_PEEKTEXT. */
3967 static enum target_xfer_status
3968 linux_proc_xfer_partial (enum target_object object
,
3969 const char *annex
, gdb_byte
*readbuf
,
3970 const gdb_byte
*writebuf
,
3971 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
3977 if (object
!= TARGET_OBJECT_MEMORY
)
3978 return TARGET_XFER_EOF
;
3980 /* Don't bother for one word. */
3981 if (len
< 3 * sizeof (long))
3982 return TARGET_XFER_EOF
;
3984 /* We could keep this file open and cache it - possibly one per
3985 thread. That requires some juggling, but is even faster. */
3986 xsnprintf (filename
, sizeof filename
, "/proc/%ld/mem",
3987 inferior_ptid
.lwp ());
3988 fd
= gdb_open_cloexec (filename
, ((readbuf
? O_RDONLY
: O_WRONLY
)
3991 return TARGET_XFER_EOF
;
3993 /* Use pread64/pwrite64 if available, since they save a syscall and can
3994 handle 64-bit offsets even on 32-bit platforms (for instance, SPARC
3995 debugging a SPARC64 application). */
3997 ret
= (readbuf
? pread64 (fd
, readbuf
, len
, offset
)
3998 : pwrite64 (fd
, writebuf
, len
, offset
));
4000 ret
= lseek (fd
, offset
, SEEK_SET
);
4002 ret
= (readbuf
? read (fd
, readbuf
, len
)
4003 : write (fd
, writebuf
, len
));
4008 if (ret
== -1 || ret
== 0)
4009 return TARGET_XFER_EOF
;
4013 return TARGET_XFER_OK
;
4018 /* Enumerate spufs IDs for process PID. */
4020 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
4022 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
4024 LONGEST written
= 0;
4027 struct dirent
*entry
;
4029 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
4030 dir
= opendir (path
);
4035 while ((entry
= readdir (dir
)) != NULL
)
4041 fd
= atoi (entry
->d_name
);
4045 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
4046 if (stat (path
, &st
) != 0)
4048 if (!S_ISDIR (st
.st_mode
))
4051 if (statfs (path
, &stfs
) != 0)
4053 if (stfs
.f_type
!= SPUFS_MAGIC
)
4056 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
4058 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
4068 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4069 object type, using the /proc file system. */
4071 static enum target_xfer_status
4072 linux_proc_xfer_spu (enum target_object object
,
4073 const char *annex
, gdb_byte
*readbuf
,
4074 const gdb_byte
*writebuf
,
4075 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
4080 int pid
= inferior_ptid
.lwp ();
4085 return TARGET_XFER_E_IO
;
4088 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4091 return TARGET_XFER_E_IO
;
4093 return TARGET_XFER_EOF
;
4096 *xfered_len
= (ULONGEST
) l
;
4097 return TARGET_XFER_OK
;
4102 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4103 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4105 return TARGET_XFER_E_IO
;
4108 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4111 return TARGET_XFER_EOF
;
4115 ret
= write (fd
, writebuf
, (size_t) len
);
4117 ret
= read (fd
, readbuf
, (size_t) len
);
4122 return TARGET_XFER_E_IO
;
4124 return TARGET_XFER_EOF
;
4127 *xfered_len
= (ULONGEST
) ret
;
4128 return TARGET_XFER_OK
;
4133 /* Parse LINE as a signal set and add its set bits to SIGS. */
4136 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4138 int len
= strlen (line
) - 1;
4142 if (line
[len
] != '\n')
4143 error (_("Could not parse signal set: %s"), line
);
4151 if (*p
>= '0' && *p
<= '9')
4153 else if (*p
>= 'a' && *p
<= 'f')
4154 digit
= *p
- 'a' + 10;
4156 error (_("Could not parse signal set: %s"), line
);
4161 sigaddset (sigs
, signum
+ 1);
4163 sigaddset (sigs
, signum
+ 2);
4165 sigaddset (sigs
, signum
+ 3);
4167 sigaddset (sigs
, signum
+ 4);
4173 /* Find process PID's pending signals from /proc/pid/status and set
4177 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4178 sigset_t
*blocked
, sigset_t
*ignored
)
4180 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4182 sigemptyset (pending
);
4183 sigemptyset (blocked
);
4184 sigemptyset (ignored
);
4185 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4186 gdb_file_up procfile
= gdb_fopen_cloexec (fname
, "r");
4187 if (procfile
== NULL
)
4188 error (_("Could not open %s"), fname
);
4190 while (fgets (buffer
, PATH_MAX
, procfile
.get ()) != NULL
)
4192 /* Normal queued signals are on the SigPnd line in the status
4193 file. However, 2.6 kernels also have a "shared" pending
4194 queue for delivering signals to a thread group, so check for
4197 Unfortunately some Red Hat kernels include the shared pending
4198 queue but not the ShdPnd status field. */
4200 if (startswith (buffer
, "SigPnd:\t"))
4201 add_line_to_sigset (buffer
+ 8, pending
);
4202 else if (startswith (buffer
, "ShdPnd:\t"))
4203 add_line_to_sigset (buffer
+ 8, pending
);
4204 else if (startswith (buffer
, "SigBlk:\t"))
4205 add_line_to_sigset (buffer
+ 8, blocked
);
4206 else if (startswith (buffer
, "SigIgn:\t"))
4207 add_line_to_sigset (buffer
+ 8, ignored
);
4211 static enum target_xfer_status
4212 linux_nat_xfer_osdata (enum target_object object
,
4213 const char *annex
, gdb_byte
*readbuf
,
4214 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4215 ULONGEST
*xfered_len
)
4217 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4219 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4220 if (*xfered_len
== 0)
4221 return TARGET_XFER_EOF
;
4223 return TARGET_XFER_OK
;
4227 cleanup_target_stop (void *arg
)
4229 ptid_t
*ptid
= (ptid_t
*) arg
;
4231 gdb_assert (arg
!= NULL
);
4234 target_continue_no_signal (*ptid
);
4237 std::vector
<static_tracepoint_marker
>
4238 linux_nat_target::static_tracepoint_markers_by_strid (const char *strid
)
4240 char s
[IPA_CMD_BUF_SIZE
];
4241 struct cleanup
*old_chain
;
4242 int pid
= inferior_ptid
.pid ();
4243 std::vector
<static_tracepoint_marker
> markers
;
4245 ptid_t ptid
= ptid_t (pid
, 0, 0);
4246 static_tracepoint_marker marker
;
4251 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4252 s
[sizeof ("qTfSTM")] = 0;
4254 agent_run_command (pid
, s
, strlen (s
) + 1);
4256 old_chain
= make_cleanup (cleanup_target_stop
, &ptid
);
4262 parse_static_tracepoint_marker_definition (p
, &p
, &marker
);
4264 if (strid
== NULL
|| marker
.str_id
== strid
)
4265 markers
.push_back (std::move (marker
));
4267 while (*p
++ == ','); /* comma-separated list */
4269 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4270 s
[sizeof ("qTsSTM")] = 0;
4271 agent_run_command (pid
, s
, strlen (s
) + 1);
4275 do_cleanups (old_chain
);
4280 /* target_is_async_p implementation. */
4283 linux_nat_target::is_async_p ()
4285 return linux_is_async_p ();
4288 /* target_can_async_p implementation. */
4291 linux_nat_target::can_async_p ()
4293 /* We're always async, unless the user explicitly prevented it with the
4294 "maint set target-async" command. */
4295 return target_async_permitted
;
4299 linux_nat_target::supports_non_stop ()
4304 /* to_always_non_stop_p implementation. */
4307 linux_nat_target::always_non_stop_p ()
4312 /* True if we want to support multi-process. To be removed when GDB
4313 supports multi-exec. */
4315 int linux_multi_process
= 1;
4318 linux_nat_target::supports_multi_process ()
4320 return linux_multi_process
;
4324 linux_nat_target::supports_disable_randomization ()
4326 #ifdef HAVE_PERSONALITY
4333 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4334 so we notice when any child changes state, and notify the
4335 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4336 above to wait for the arrival of a SIGCHLD. */
4339 sigchld_handler (int signo
)
4341 int old_errno
= errno
;
4343 if (debug_linux_nat
)
4344 ui_file_write_async_safe (gdb_stdlog
,
4345 "sigchld\n", sizeof ("sigchld\n") - 1);
4347 if (signo
== SIGCHLD
4348 && linux_nat_event_pipe
[0] != -1)
4349 async_file_mark (); /* Let the event loop know that there are
4350 events to handle. */
4355 /* Callback registered with the target events file descriptor. */
4358 handle_target_event (int error
, gdb_client_data client_data
)
4360 inferior_event_handler (INF_REG_EVENT
, NULL
);
4363 /* Create/destroy the target events pipe. Returns previous state. */
4366 linux_async_pipe (int enable
)
4368 int previous
= linux_is_async_p ();
4370 if (previous
!= enable
)
4374 /* Block child signals while we create/destroy the pipe, as
4375 their handler writes to it. */
4376 block_child_signals (&prev_mask
);
4380 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4381 internal_error (__FILE__
, __LINE__
,
4382 "creating event pipe failed.");
4384 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4385 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4389 close (linux_nat_event_pipe
[0]);
4390 close (linux_nat_event_pipe
[1]);
4391 linux_nat_event_pipe
[0] = -1;
4392 linux_nat_event_pipe
[1] = -1;
4395 restore_child_signals_mask (&prev_mask
);
4401 /* target_async implementation. */
4404 linux_nat_target::async (int enable
)
4408 if (!linux_async_pipe (1))
4410 add_file_handler (linux_nat_event_pipe
[0],
4411 handle_target_event
, NULL
);
4412 /* There may be pending events to handle. Tell the event loop
4419 delete_file_handler (linux_nat_event_pipe
[0]);
4420 linux_async_pipe (0);
4425 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4429 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4433 if (debug_linux_nat
)
4434 fprintf_unfiltered (gdb_stdlog
,
4435 "LNSL: running -> suspending %s\n",
4436 target_pid_to_str (lwp
->ptid
));
4439 if (lwp
->last_resume_kind
== resume_stop
)
4441 if (debug_linux_nat
)
4442 fprintf_unfiltered (gdb_stdlog
,
4443 "linux-nat: already stopping LWP %ld at "
4449 stop_callback (lwp
, NULL
);
4450 lwp
->last_resume_kind
= resume_stop
;
4454 /* Already known to be stopped; do nothing. */
4456 if (debug_linux_nat
)
4458 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4459 fprintf_unfiltered (gdb_stdlog
,
4460 "LNSL: already stopped/stop_requested %s\n",
4461 target_pid_to_str (lwp
->ptid
));
4463 fprintf_unfiltered (gdb_stdlog
,
4464 "LNSL: already stopped/no "
4465 "stop_requested yet %s\n",
4466 target_pid_to_str (lwp
->ptid
));
4473 linux_nat_target::stop (ptid_t ptid
)
4475 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4479 linux_nat_target::close ()
4481 /* Unregister from the event loop. */
4485 inf_ptrace_target::close ();
4488 /* When requests are passed down from the linux-nat layer to the
4489 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4490 used. The address space pointer is stored in the inferior object,
4491 but the common code that is passed such ptid can't tell whether
4492 lwpid is a "main" process id or not (it assumes so). We reverse
4493 look up the "main" process id from the lwp here. */
4495 struct address_space
*
4496 linux_nat_target::thread_address_space (ptid_t ptid
)
4498 struct lwp_info
*lwp
;
4499 struct inferior
*inf
;
4502 if (ptid
.lwp () == 0)
4504 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4506 lwp
= find_lwp_pid (ptid
);
4507 pid
= lwp
->ptid
.pid ();
4511 /* A (pid,lwpid,0) ptid. */
4515 inf
= find_inferior_pid (pid
);
4516 gdb_assert (inf
!= NULL
);
4520 /* Return the cached value of the processor core for thread PTID. */
4523 linux_nat_target::core_of_thread (ptid_t ptid
)
4525 struct lwp_info
*info
= find_lwp_pid (ptid
);
4532 /* Implementation of to_filesystem_is_local. */
4535 linux_nat_target::filesystem_is_local ()
4537 struct inferior
*inf
= current_inferior ();
4539 if (inf
->fake_pid_p
|| inf
->pid
== 0)
4542 return linux_ns_same (inf
->pid
, LINUX_NS_MNT
);
4545 /* Convert the INF argument passed to a to_fileio_* method
4546 to a process ID suitable for passing to its corresponding
4547 linux_mntns_* function. If INF is non-NULL then the
4548 caller is requesting the filesystem seen by INF. If INF
4549 is NULL then the caller is requesting the filesystem seen
4550 by the GDB. We fall back to GDB's filesystem in the case
4551 that INF is non-NULL but its PID is unknown. */
4554 linux_nat_fileio_pid_of (struct inferior
*inf
)
4556 if (inf
== NULL
|| inf
->fake_pid_p
|| inf
->pid
== 0)
4562 /* Implementation of to_fileio_open. */
4565 linux_nat_target::fileio_open (struct inferior
*inf
, const char *filename
,
4566 int flags
, int mode
, int warn_if_slow
,
4573 if (fileio_to_host_openflags (flags
, &nat_flags
) == -1
4574 || fileio_to_host_mode (mode
, &nat_mode
) == -1)
4576 *target_errno
= FILEIO_EINVAL
;
4580 fd
= linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf
),
4581 filename
, nat_flags
, nat_mode
);
4583 *target_errno
= host_to_fileio_error (errno
);
4588 /* Implementation of to_fileio_readlink. */
4590 gdb::optional
<std::string
>
4591 linux_nat_target::fileio_readlink (struct inferior
*inf
, const char *filename
,
4597 len
= linux_mntns_readlink (linux_nat_fileio_pid_of (inf
),
4598 filename
, buf
, sizeof (buf
));
4601 *target_errno
= host_to_fileio_error (errno
);
4605 return std::string (buf
, len
);
4608 /* Implementation of to_fileio_unlink. */
4611 linux_nat_target::fileio_unlink (struct inferior
*inf
, const char *filename
,
4616 ret
= linux_mntns_unlink (linux_nat_fileio_pid_of (inf
),
4619 *target_errno
= host_to_fileio_error (errno
);
4624 /* Implementation of the to_thread_events method. */
4627 linux_nat_target::thread_events (int enable
)
4629 report_thread_events
= enable
;
4632 linux_nat_target::linux_nat_target ()
4634 /* We don't change the stratum; this target will sit at
4635 process_stratum and thread_db will set at thread_stratum. This
4636 is a little strange, since this is a multi-threaded-capable
4637 target, but we want to be on the stack below thread_db, and we
4638 also want to be used for single-threaded processes. */
4641 /* See linux-nat.h. */
4644 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4653 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4656 memset (siginfo
, 0, sizeof (*siginfo
));
4662 /* See nat/linux-nat.h. */
4665 current_lwp_ptid (void)
4667 gdb_assert (inferior_ptid
.lwp_p ());
4668 return inferior_ptid
;
4672 _initialize_linux_nat (void)
4674 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4675 &debug_linux_nat
, _("\
4676 Set debugging of GNU/Linux lwp module."), _("\
4677 Show debugging of GNU/Linux lwp module."), _("\
4678 Enables printf debugging output."),
4680 show_debug_linux_nat
,
4681 &setdebuglist
, &showdebuglist
);
4683 add_setshow_boolean_cmd ("linux-namespaces", class_maintenance
,
4684 &debug_linux_namespaces
, _("\
4685 Set debugging of GNU/Linux namespaces module."), _("\
4686 Show debugging of GNU/Linux namespaces module."), _("\
4687 Enables printf debugging output."),
4690 &setdebuglist
, &showdebuglist
);
4692 /* Save this mask as the default. */
4693 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
4695 /* Install a SIGCHLD handler. */
4696 sigchld_action
.sa_handler
= sigchld_handler
;
4697 sigemptyset (&sigchld_action
.sa_mask
);
4698 sigchld_action
.sa_flags
= SA_RESTART
;
4700 /* Make it the default. */
4701 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4703 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4704 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4705 sigdelset (&suspend_mask
, SIGCHLD
);
4707 sigemptyset (&blocked_mask
);
4709 lwp_lwpid_htab_create ();
4713 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4714 the GNU/Linux Threads library and therefore doesn't really belong
4717 /* Return the set of signals used by the threads library in *SET. */
4720 lin_thread_get_thread_signals (sigset_t
*set
)
4724 /* NPTL reserves the first two RT signals, but does not provide any
4725 way for the debugger to query the signal numbers - fortunately
4726 they don't change. */
4727 sigaddset (set
, __SIGRTMIN
);
4728 sigaddset (set
, __SIGRTMIN
+ 1);