1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2020 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"
26 #include "gdbsupport/gdb_wait.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"
61 #include "gdbsupport/agent.h"
62 #include "tracepoint.h"
63 #include "gdbsupport/buffer.h"
64 #include "target-descriptions.h"
65 #include "gdbsupport/filestuff.h"
67 #include "nat/linux-namespaces.h"
68 #include "gdbsupport/fileio.h"
69 #include "gdbsupport/scope-exit.h"
70 #include "gdbsupport/gdb-sigmask.h"
72 /* This comment documents high-level logic of this file.
74 Waiting for events in sync mode
75 ===============================
77 When waiting for an event in a specific thread, we just use waitpid,
78 passing the specific pid, and not passing WNOHANG.
80 When waiting for an event in all threads, waitpid is not quite good:
82 - If the thread group leader exits while other threads in the thread
83 group still exist, waitpid(TGID, ...) hangs. That waitpid won't
84 return an exit status until the other threads in the group are
87 - When a non-leader thread execs, that thread just vanishes without
88 reporting an exit (so we'd hang if we waited for it explicitly in
89 that case). The exec event is instead reported to the TGID pid.
91 The solution is to always use -1 and WNOHANG, together with
94 First, we use non-blocking waitpid to check for events. If nothing is
95 found, we use sigsuspend to wait for SIGCHLD. When SIGCHLD arrives,
96 it means something happened to a child process. As soon as we know
97 there's an event, we get back to calling nonblocking waitpid.
99 Note that SIGCHLD should be blocked between waitpid and sigsuspend
100 calls, so that we don't miss a signal. If SIGCHLD arrives in between,
101 when it's blocked, the signal becomes pending and sigsuspend
102 immediately notices it and returns.
104 Waiting for events in async mode (TARGET_WNOHANG)
105 =================================================
107 In async mode, GDB should always be ready to handle both user input
108 and target events, so neither blocking waitpid nor sigsuspend are
109 viable options. Instead, we should asynchronously notify the GDB main
110 event loop whenever there's an unprocessed event from the target. We
111 detect asynchronous target events by handling SIGCHLD signals. To
112 notify the event loop about target events, the self-pipe trick is used
113 --- a pipe is registered as waitable event source in the event loop,
114 the event loop select/poll's on the read end of this pipe (as well on
115 other event sources, e.g., stdin), and the SIGCHLD handler writes a
116 byte to this pipe. This is more portable than relying on
117 pselect/ppoll, since on kernels that lack those syscalls, libc
118 emulates them with select/poll+sigprocmask, and that is racy
119 (a.k.a. plain broken).
121 Obviously, if we fail to notify the event loop if there's a target
122 event, it's bad. OTOH, if we notify the event loop when there's no
123 event from the target, linux_nat_wait will detect that there's no real
124 event to report, and return event of type TARGET_WAITKIND_IGNORE.
125 This is mostly harmless, but it will waste time and is better avoided.
127 The main design point is that every time GDB is outside linux-nat.c,
128 we have a SIGCHLD handler installed that is called when something
129 happens to the target and notifies the GDB event loop. Whenever GDB
130 core decides to handle the event, and calls into linux-nat.c, we
131 process things as in sync mode, except that the we never block in
134 While processing an event, we may end up momentarily blocked in
135 waitpid calls. Those waitpid calls, while blocking, are guarantied to
136 return quickly. E.g., in all-stop mode, before reporting to the core
137 that an LWP hit a breakpoint, all LWPs are stopped by sending them
138 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
139 Note that this is different from blocking indefinitely waiting for the
140 next event --- here, we're already handling an event.
145 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
146 signal is not entirely significant; we just need for a signal to be delivered,
147 so that we can intercept it. SIGSTOP's advantage is that it can not be
148 blocked. A disadvantage is that it is not a real-time signal, so it can only
149 be queued once; we do not keep track of other sources of SIGSTOP.
151 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
152 use them, because they have special behavior when the signal is generated -
153 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
154 kills the entire thread group.
156 A delivered SIGSTOP would stop the entire thread group, not just the thread we
157 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
158 cancel it (by PTRACE_CONT without passing SIGSTOP).
160 We could use a real-time signal instead. This would solve those problems; we
161 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
162 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
163 generates it, and there are races with trying to find a signal that is not
169 The case of a thread group (process) with 3 or more threads, and a
170 thread other than the leader execs is worth detailing:
172 On an exec, the Linux kernel destroys all threads except the execing
173 one in the thread group, and resets the execing thread's tid to the
174 tgid. No exit notification is sent for the execing thread -- from the
175 ptracer's perspective, it appears as though the execing thread just
176 vanishes. Until we reap all other threads except the leader and the
177 execing thread, the leader will be zombie, and the execing thread will
178 be in `D (disc sleep)' state. As soon as all other threads are
179 reaped, the execing thread changes its tid to the tgid, and the
180 previous (zombie) leader vanishes, giving place to the "new"
184 #define O_LARGEFILE 0
187 struct linux_nat_target
*linux_target
;
189 /* Does the current host support PTRACE_GETREGSET? */
190 enum tribool have_ptrace_getregset
= TRIBOOL_UNKNOWN
;
192 static unsigned int debug_linux_nat
;
194 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
195 struct cmd_list_element
*c
, const char *value
)
197 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
201 struct simple_pid_list
205 struct simple_pid_list
*next
;
207 struct simple_pid_list
*stopped_pids
;
209 /* Whether target_thread_events is in effect. */
210 static int report_thread_events
;
212 /* Async mode support. */
214 /* The read/write ends of the pipe registered as waitable file in the
216 static int linux_nat_event_pipe
[2] = { -1, -1 };
218 /* True if we're currently in async mode. */
219 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
221 /* Flush the event pipe. */
224 async_file_flush (void)
231 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
233 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
236 /* Put something (anything, doesn't matter what, or how much) in event
237 pipe, so that the select/poll in the event-loop realizes we have
238 something to process. */
241 async_file_mark (void)
245 /* It doesn't really matter what the pipe contains, as long we end
246 up with something in it. Might as well flush the previous
252 ret
= write (linux_nat_event_pipe
[1], "+", 1);
254 while (ret
== -1 && errno
== EINTR
);
256 /* Ignore EAGAIN. If the pipe is full, the event loop will already
257 be awakened anyway. */
260 static int kill_lwp (int lwpid
, int signo
);
262 static int stop_callback (struct lwp_info
*lp
);
264 static void block_child_signals (sigset_t
*prev_mask
);
265 static void restore_child_signals_mask (sigset_t
*prev_mask
);
268 static struct lwp_info
*add_lwp (ptid_t ptid
);
269 static void purge_lwp_list (int pid
);
270 static void delete_lwp (ptid_t ptid
);
271 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
273 static int lwp_status_pending_p (struct lwp_info
*lp
);
275 static void save_stop_reason (struct lwp_info
*lp
);
280 /* See nat/linux-nat.h. */
283 ptid_of_lwp (struct lwp_info
*lwp
)
288 /* See nat/linux-nat.h. */
291 lwp_set_arch_private_info (struct lwp_info
*lwp
,
292 struct arch_lwp_info
*info
)
294 lwp
->arch_private
= info
;
297 /* See nat/linux-nat.h. */
299 struct arch_lwp_info
*
300 lwp_arch_private_info (struct lwp_info
*lwp
)
302 return lwp
->arch_private
;
305 /* See nat/linux-nat.h. */
308 lwp_is_stopped (struct lwp_info
*lwp
)
313 /* See nat/linux-nat.h. */
315 enum target_stop_reason
316 lwp_stop_reason (struct lwp_info
*lwp
)
318 return lwp
->stop_reason
;
321 /* See nat/linux-nat.h. */
324 lwp_is_stepping (struct lwp_info
*lwp
)
330 /* Trivial list manipulation functions to keep track of a list of
331 new stopped processes. */
333 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
335 struct simple_pid_list
*new_pid
= XNEW (struct simple_pid_list
);
338 new_pid
->status
= status
;
339 new_pid
->next
= *listp
;
344 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
346 struct simple_pid_list
**p
;
348 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
349 if ((*p
)->pid
== pid
)
351 struct simple_pid_list
*next
= (*p
)->next
;
353 *statusp
= (*p
)->status
;
361 /* Return the ptrace options that we want to try to enable. */
364 linux_nat_ptrace_options (int attached
)
369 options
|= PTRACE_O_EXITKILL
;
371 options
|= (PTRACE_O_TRACESYSGOOD
372 | PTRACE_O_TRACEVFORKDONE
373 | PTRACE_O_TRACEVFORK
375 | PTRACE_O_TRACEEXEC
);
380 /* Initialize ptrace and procfs warnings and check for supported
381 ptrace features given PID.
383 ATTACHED should be nonzero iff we attached to the inferior. */
386 linux_init_ptrace_procfs (pid_t pid
, int attached
)
388 int options
= linux_nat_ptrace_options (attached
);
390 linux_enable_event_reporting (pid
, options
);
391 linux_ptrace_init_warnings ();
392 linux_proc_init_warnings ();
395 linux_nat_target::~linux_nat_target ()
399 linux_nat_target::post_attach (int pid
)
401 linux_init_ptrace_procfs (pid
, 1);
405 linux_nat_target::post_startup_inferior (ptid_t ptid
)
407 linux_init_ptrace_procfs (ptid
.pid (), 0);
410 /* Return the number of known LWPs in the tgid given by PID. */
418 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
419 if (lp
->ptid
.pid () == pid
)
425 /* Deleter for lwp_info unique_ptr specialisation. */
429 void operator() (struct lwp_info
*lwp
) const
431 delete_lwp (lwp
->ptid
);
435 /* A unique_ptr specialisation for lwp_info. */
437 typedef std::unique_ptr
<struct lwp_info
, lwp_deleter
> lwp_info_up
;
439 /* Target hook for follow_fork. On entry inferior_ptid must be the
440 ptid of the followed inferior. At return, inferior_ptid will be
444 linux_nat_target::follow_fork (int follow_child
, int detach_fork
)
448 struct lwp_info
*child_lp
= NULL
;
450 ptid_t parent_ptid
, child_ptid
;
451 int parent_pid
, child_pid
;
453 has_vforked
= (inferior_thread ()->pending_follow
.kind
454 == TARGET_WAITKIND_VFORKED
);
455 parent_ptid
= inferior_ptid
;
456 child_ptid
= inferior_thread ()->pending_follow
.value
.related_pid
;
457 parent_pid
= parent_ptid
.lwp ();
458 child_pid
= child_ptid
.lwp ();
460 /* We're already attached to the parent, by default. */
461 child_lp
= add_lwp (child_ptid
);
462 child_lp
->stopped
= 1;
463 child_lp
->last_resume_kind
= resume_stop
;
465 /* Detach new forked process? */
468 int child_stop_signal
= 0;
469 bool detach_child
= true;
471 /* Move CHILD_LP into a unique_ptr and clear the source pointer
472 to prevent us doing anything stupid with it. */
473 lwp_info_up
child_lp_ptr (child_lp
);
476 linux_target
->low_prepare_to_resume (child_lp_ptr
.get ());
478 /* When debugging an inferior in an architecture that supports
479 hardware single stepping on a kernel without commit
480 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
481 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
482 set if the parent process had them set.
483 To work around this, single step the child process
484 once before detaching to clear the flags. */
486 /* Note that we consult the parent's architecture instead of
487 the child's because there's no inferior for the child at
489 if (!gdbarch_software_single_step_p (target_thread_architecture
494 linux_disable_event_reporting (child_pid
);
495 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
496 perror_with_name (_("Couldn't do single step"));
497 if (my_waitpid (child_pid
, &status
, 0) < 0)
498 perror_with_name (_("Couldn't wait vfork process"));
501 detach_child
= WIFSTOPPED (status
);
502 child_stop_signal
= WSTOPSIG (status
);
508 int signo
= child_stop_signal
;
511 && !signal_pass_state (gdb_signal_from_host (signo
)))
513 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
518 /* Switching inferior_ptid is not enough, because then
519 inferior_thread () would crash by not finding the thread
520 in the current inferior. */
521 scoped_restore_current_thread restore_current_thread
;
522 thread_info
*child
= find_thread_ptid (this, child_ptid
);
523 switch_to_thread (child
);
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 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
752 _initialize_linux_nat. */
753 static sigset_t suspend_mask
;
755 /* Signals to block to make that sigsuspend work. */
756 static sigset_t blocked_mask
;
758 /* SIGCHLD action. */
759 struct sigaction sigchld_action
;
761 /* Block child signals (SIGCHLD and linux threads signals), and store
762 the previous mask in PREV_MASK. */
765 block_child_signals (sigset_t
*prev_mask
)
767 /* Make sure SIGCHLD is blocked. */
768 if (!sigismember (&blocked_mask
, SIGCHLD
))
769 sigaddset (&blocked_mask
, SIGCHLD
);
771 gdb_sigmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
774 /* Restore child signals mask, previously returned by
775 block_child_signals. */
778 restore_child_signals_mask (sigset_t
*prev_mask
)
780 gdb_sigmask (SIG_SETMASK
, prev_mask
, NULL
);
783 /* Mask of signals to pass directly to the inferior. */
784 static sigset_t pass_mask
;
786 /* Update signals to pass to the inferior. */
788 linux_nat_target::pass_signals
789 (gdb::array_view
<const unsigned char> pass_signals
)
793 sigemptyset (&pass_mask
);
795 for (signo
= 1; signo
< NSIG
; signo
++)
797 int target_signo
= gdb_signal_from_host (signo
);
798 if (target_signo
< pass_signals
.size () && pass_signals
[target_signo
])
799 sigaddset (&pass_mask
, signo
);
805 /* Prototypes for local functions. */
806 static int stop_wait_callback (struct lwp_info
*lp
);
807 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, const ptid_t wait_ptid
);
808 static int check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
);
812 /* Destroy and free LP. */
815 lwp_free (struct lwp_info
*lp
)
817 /* Let the arch specific bits release arch_lwp_info. */
818 linux_target
->low_delete_thread (lp
->arch_private
);
823 /* Traversal function for purge_lwp_list. */
826 lwp_lwpid_htab_remove_pid (void **slot
, void *info
)
828 struct lwp_info
*lp
= (struct lwp_info
*) *slot
;
829 int pid
= *(int *) info
;
831 if (lp
->ptid
.pid () == pid
)
833 htab_clear_slot (lwp_lwpid_htab
, slot
);
834 lwp_list_remove (lp
);
841 /* Remove all LWPs belong to PID from the lwp list. */
844 purge_lwp_list (int pid
)
846 htab_traverse_noresize (lwp_lwpid_htab
, lwp_lwpid_htab_remove_pid
, &pid
);
849 /* Add the LWP specified by PTID to the list. PTID is the first LWP
850 in the process. Return a pointer to the structure describing the
853 This differs from add_lwp in that we don't let the arch specific
854 bits know about this new thread. Current clients of this callback
855 take the opportunity to install watchpoints in the new thread, and
856 we shouldn't do that for the first thread. If we're spawning a
857 child ("run"), the thread executes the shell wrapper first, and we
858 shouldn't touch it until it execs the program we want to debug.
859 For "attach", it'd be okay to call the callback, but it's not
860 necessary, because watchpoints can't yet have been inserted into
863 static struct lwp_info
*
864 add_initial_lwp (ptid_t ptid
)
868 gdb_assert (ptid
.lwp_p ());
870 lp
= XNEW (struct lwp_info
);
872 memset (lp
, 0, sizeof (struct lwp_info
));
874 lp
->last_resume_kind
= resume_continue
;
875 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
880 /* Add to sorted-by-reverse-creation-order list. */
883 /* Add to keyed-by-pid htab. */
884 lwp_lwpid_htab_add_lwp (lp
);
889 /* Add the LWP specified by PID to the list. Return a pointer to the
890 structure describing the new LWP. The LWP should already be
893 static struct lwp_info
*
894 add_lwp (ptid_t ptid
)
898 lp
= add_initial_lwp (ptid
);
900 /* Let the arch specific bits know about this new thread. Current
901 clients of this callback take the opportunity to install
902 watchpoints in the new thread. We don't do this for the first
903 thread though. See add_initial_lwp. */
904 linux_target
->low_new_thread (lp
);
909 /* Remove the LWP specified by PID from the list. */
912 delete_lwp (ptid_t ptid
)
916 struct lwp_info dummy
;
919 slot
= htab_find_slot (lwp_lwpid_htab
, &dummy
, NO_INSERT
);
923 lp
= *(struct lwp_info
**) slot
;
924 gdb_assert (lp
!= NULL
);
926 htab_clear_slot (lwp_lwpid_htab
, slot
);
928 /* Remove from sorted-by-creation-order list. */
929 lwp_list_remove (lp
);
935 /* Return a pointer to the structure describing the LWP corresponding
936 to PID. If no corresponding LWP could be found, return NULL. */
938 static struct lwp_info
*
939 find_lwp_pid (ptid_t ptid
)
943 struct lwp_info dummy
;
950 dummy
.ptid
= ptid_t (0, lwp
, 0);
951 lp
= (struct lwp_info
*) htab_find (lwp_lwpid_htab
, &dummy
);
955 /* See nat/linux-nat.h. */
958 iterate_over_lwps (ptid_t filter
,
959 gdb::function_view
<iterate_over_lwps_ftype
> callback
)
961 struct lwp_info
*lp
, *lpnext
;
963 for (lp
= lwp_list
; lp
; lp
= lpnext
)
967 if (lp
->ptid
.matches (filter
))
969 if (callback (lp
) != 0)
977 /* Update our internal state when changing from one checkpoint to
978 another indicated by NEW_PTID. We can only switch single-threaded
979 applications, so we only create one new LWP, and the previous list
983 linux_nat_switch_fork (ptid_t new_ptid
)
987 purge_lwp_list (inferior_ptid
.pid ());
989 lp
= add_lwp (new_ptid
);
992 /* This changes the thread's ptid while preserving the gdb thread
993 num. Also changes the inferior pid, while preserving the
995 thread_change_ptid (linux_target
, inferior_ptid
, new_ptid
);
997 /* We've just told GDB core that the thread changed target id, but,
998 in fact, it really is a different thread, with different register
1000 registers_changed ();
1003 /* Handle the exit of a single thread LP. */
1006 exit_lwp (struct lwp_info
*lp
)
1008 struct thread_info
*th
= find_thread_ptid (linux_target
, lp
->ptid
);
1012 if (print_thread_events
)
1013 printf_unfiltered (_("[%s exited]\n"),
1014 target_pid_to_str (lp
->ptid
).c_str ());
1019 delete_lwp (lp
->ptid
);
1022 /* Wait for the LWP specified by LP, which we have just attached to.
1023 Returns a wait status for that LWP, to cache. */
1026 linux_nat_post_attach_wait (ptid_t ptid
, int *signalled
)
1028 pid_t new_pid
, pid
= ptid
.lwp ();
1031 if (linux_proc_pid_is_stopped (pid
))
1033 if (debug_linux_nat
)
1034 fprintf_unfiltered (gdb_stdlog
,
1035 "LNPAW: Attaching to a stopped process\n");
1037 /* The process is definitely stopped. It is in a job control
1038 stop, unless the kernel predates the TASK_STOPPED /
1039 TASK_TRACED distinction, in which case it might be in a
1040 ptrace stop. Make sure it is in a ptrace stop; from there we
1041 can kill it, signal it, et cetera.
1043 First make sure there is a pending SIGSTOP. Since we are
1044 already attached, the process can not transition from stopped
1045 to running without a PTRACE_CONT; so we know this signal will
1046 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1047 probably already in the queue (unless this kernel is old
1048 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1049 is not an RT signal, it can only be queued once. */
1050 kill_lwp (pid
, SIGSTOP
);
1052 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1053 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1054 ptrace (PTRACE_CONT
, pid
, 0, 0);
1057 /* Make sure the initial process is stopped. The user-level threads
1058 layer might want to poke around in the inferior, and that won't
1059 work if things haven't stabilized yet. */
1060 new_pid
= my_waitpid (pid
, &status
, __WALL
);
1061 gdb_assert (pid
== new_pid
);
1063 if (!WIFSTOPPED (status
))
1065 /* The pid we tried to attach has apparently just exited. */
1066 if (debug_linux_nat
)
1067 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1068 pid
, status_to_str (status
));
1072 if (WSTOPSIG (status
) != SIGSTOP
)
1075 if (debug_linux_nat
)
1076 fprintf_unfiltered (gdb_stdlog
,
1077 "LNPAW: Received %s after attaching\n",
1078 status_to_str (status
));
1085 linux_nat_target::create_inferior (const char *exec_file
,
1086 const std::string
&allargs
,
1087 char **env
, int from_tty
)
1089 maybe_disable_address_space_randomization restore_personality
1090 (disable_randomization
);
1092 /* The fork_child mechanism is synchronous and calls target_wait, so
1093 we have to mask the async mode. */
1095 /* Make sure we report all signals during startup. */
1098 inf_ptrace_target::create_inferior (exec_file
, allargs
, env
, from_tty
);
1101 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1102 already attached. Returns true if a new LWP is found, false
1106 attach_proc_task_lwp_callback (ptid_t ptid
)
1108 struct lwp_info
*lp
;
1110 /* Ignore LWPs we're already attached to. */
1111 lp
= find_lwp_pid (ptid
);
1114 int lwpid
= ptid
.lwp ();
1116 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1120 /* Be quiet if we simply raced with the thread exiting.
1121 EPERM is returned if the thread's task still exists, and
1122 is marked as exited or zombie, as well as other
1123 conditions, so in that case, confirm the status in
1124 /proc/PID/status. */
1126 || (err
== EPERM
&& linux_proc_pid_is_gone (lwpid
)))
1128 if (debug_linux_nat
)
1130 fprintf_unfiltered (gdb_stdlog
,
1131 "Cannot attach to lwp %d: "
1132 "thread is gone (%d: %s)\n",
1133 lwpid
, err
, safe_strerror (err
));
1139 = linux_ptrace_attach_fail_reason_string (ptid
, err
);
1141 warning (_("Cannot attach to lwp %d: %s"),
1142 lwpid
, reason
.c_str ());
1147 if (debug_linux_nat
)
1148 fprintf_unfiltered (gdb_stdlog
,
1149 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1150 target_pid_to_str (ptid
).c_str ());
1152 lp
= add_lwp (ptid
);
1154 /* The next time we wait for this LWP we'll see a SIGSTOP as
1155 PTRACE_ATTACH brings it to a halt. */
1158 /* We need to wait for a stop before being able to make the
1159 next ptrace call on this LWP. */
1160 lp
->must_set_ptrace_flags
= 1;
1162 /* So that wait collects the SIGSTOP. */
1165 /* Also add the LWP to gdb's thread list, in case a
1166 matching libthread_db is not found (or the process uses
1168 add_thread (linux_target
, lp
->ptid
);
1169 set_running (linux_target
, lp
->ptid
, 1);
1170 set_executing (linux_target
, lp
->ptid
, 1);
1179 linux_nat_target::attach (const char *args
, int from_tty
)
1181 struct lwp_info
*lp
;
1185 /* Make sure we report all signals during attach. */
1190 inf_ptrace_target::attach (args
, from_tty
);
1192 catch (const gdb_exception_error
&ex
)
1194 pid_t pid
= parse_pid_to_attach (args
);
1195 std::string reason
= linux_ptrace_attach_fail_reason (pid
);
1197 if (!reason
.empty ())
1198 throw_error (ex
.error
, "warning: %s\n%s", reason
.c_str (),
1201 throw_error (ex
.error
, "%s", ex
.what ());
1204 /* The ptrace base target adds the main thread with (pid,0,0)
1205 format. Decorate it with lwp info. */
1206 ptid
= ptid_t (inferior_ptid
.pid (),
1207 inferior_ptid
.pid (),
1209 thread_change_ptid (linux_target
, inferior_ptid
, ptid
);
1211 /* Add the initial process as the first LWP to the list. */
1212 lp
= add_initial_lwp (ptid
);
1214 status
= linux_nat_post_attach_wait (lp
->ptid
, &lp
->signalled
);
1215 if (!WIFSTOPPED (status
))
1217 if (WIFEXITED (status
))
1219 int exit_code
= WEXITSTATUS (status
);
1221 target_terminal::ours ();
1222 target_mourn_inferior (inferior_ptid
);
1224 error (_("Unable to attach: program exited normally."));
1226 error (_("Unable to attach: program exited with code %d."),
1229 else if (WIFSIGNALED (status
))
1231 enum gdb_signal signo
;
1233 target_terminal::ours ();
1234 target_mourn_inferior (inferior_ptid
);
1236 signo
= gdb_signal_from_host (WTERMSIG (status
));
1237 error (_("Unable to attach: program terminated with signal "
1239 gdb_signal_to_name (signo
),
1240 gdb_signal_to_string (signo
));
1243 internal_error (__FILE__
, __LINE__
,
1244 _("unexpected status %d for PID %ld"),
1245 status
, (long) ptid
.lwp ());
1250 /* Save the wait status to report later. */
1252 if (debug_linux_nat
)
1253 fprintf_unfiltered (gdb_stdlog
,
1254 "LNA: waitpid %ld, saving status %s\n",
1255 (long) lp
->ptid
.pid (), status_to_str (status
));
1257 lp
->status
= status
;
1259 /* We must attach to every LWP. If /proc is mounted, use that to
1260 find them now. The inferior may be using raw clone instead of
1261 using pthreads. But even if it is using pthreads, thread_db
1262 walks structures in the inferior's address space to find the list
1263 of threads/LWPs, and those structures may well be corrupted.
1264 Note that once thread_db is loaded, we'll still use it to list
1265 threads and associate pthread info with each LWP. */
1266 linux_proc_attach_tgid_threads (lp
->ptid
.pid (),
1267 attach_proc_task_lwp_callback
);
1269 if (target_can_async_p ())
1273 /* Get pending signal of THREAD as a host signal number, for detaching
1274 purposes. This is the signal the thread last stopped for, which we
1275 need to deliver to the thread when detaching, otherwise, it'd be
1279 get_detach_signal (struct lwp_info
*lp
)
1281 enum gdb_signal signo
= GDB_SIGNAL_0
;
1283 /* If we paused threads momentarily, we may have stored pending
1284 events in lp->status or lp->waitstatus (see stop_wait_callback),
1285 and GDB core hasn't seen any signal for those threads.
1286 Otherwise, the last signal reported to the core is found in the
1287 thread object's stop_signal.
1289 There's a corner case that isn't handled here at present. Only
1290 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1291 stop_signal make sense as a real signal to pass to the inferior.
1292 Some catchpoint related events, like
1293 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1294 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1295 those traps are debug API (ptrace in our case) related and
1296 induced; the inferior wouldn't see them if it wasn't being
1297 traced. Hence, we should never pass them to the inferior, even
1298 when set to pass state. Since this corner case isn't handled by
1299 infrun.c when proceeding with a signal, for consistency, neither
1300 do we handle it here (or elsewhere in the file we check for
1301 signal pass state). Normally SIGTRAP isn't set to pass state, so
1302 this is really a corner case. */
1304 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1305 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1306 else if (lp
->status
)
1307 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1310 struct thread_info
*tp
= find_thread_ptid (linux_target
, lp
->ptid
);
1312 if (target_is_non_stop_p () && !tp
->executing
)
1314 if (tp
->suspend
.waitstatus_pending_p
)
1315 signo
= tp
->suspend
.waitstatus
.value
.sig
;
1317 signo
= tp
->suspend
.stop_signal
;
1319 else if (!target_is_non_stop_p ())
1322 process_stratum_target
*last_target
;
1324 get_last_target_status (&last_target
, &last_ptid
, nullptr);
1326 if (last_target
== linux_target
1327 && lp
->ptid
.lwp () == last_ptid
.lwp ())
1328 signo
= tp
->suspend
.stop_signal
;
1332 if (signo
== GDB_SIGNAL_0
)
1334 if (debug_linux_nat
)
1335 fprintf_unfiltered (gdb_stdlog
,
1336 "GPT: lwp %s has no pending signal\n",
1337 target_pid_to_str (lp
->ptid
).c_str ());
1339 else if (!signal_pass_state (signo
))
1341 if (debug_linux_nat
)
1342 fprintf_unfiltered (gdb_stdlog
,
1343 "GPT: lwp %s had signal %s, "
1344 "but it is in no pass state\n",
1345 target_pid_to_str (lp
->ptid
).c_str (),
1346 gdb_signal_to_string (signo
));
1350 if (debug_linux_nat
)
1351 fprintf_unfiltered (gdb_stdlog
,
1352 "GPT: lwp %s has pending signal %s\n",
1353 target_pid_to_str (lp
->ptid
).c_str (),
1354 gdb_signal_to_string (signo
));
1356 return gdb_signal_to_host (signo
);
1362 /* Detach from LP. If SIGNO_P is non-NULL, then it points to the
1363 signal number that should be passed to the LWP when detaching.
1364 Otherwise pass any pending signal the LWP may have, if any. */
1367 detach_one_lwp (struct lwp_info
*lp
, int *signo_p
)
1369 int lwpid
= lp
->ptid
.lwp ();
1372 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1374 if (debug_linux_nat
&& lp
->status
)
1375 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1376 strsignal (WSTOPSIG (lp
->status
)),
1377 target_pid_to_str (lp
->ptid
).c_str ());
1379 /* If there is a pending SIGSTOP, get rid of it. */
1382 if (debug_linux_nat
)
1383 fprintf_unfiltered (gdb_stdlog
,
1384 "DC: Sending SIGCONT to %s\n",
1385 target_pid_to_str (lp
->ptid
).c_str ());
1387 kill_lwp (lwpid
, SIGCONT
);
1391 if (signo_p
== NULL
)
1393 /* Pass on any pending signal for this LWP. */
1394 signo
= get_detach_signal (lp
);
1399 /* Preparing to resume may try to write registers, and fail if the
1400 lwp is zombie. If that happens, ignore the error. We'll handle
1401 it below, when detach fails with ESRCH. */
1404 linux_target
->low_prepare_to_resume (lp
);
1406 catch (const gdb_exception_error
&ex
)
1408 if (!check_ptrace_stopped_lwp_gone (lp
))
1412 if (ptrace (PTRACE_DETACH
, lwpid
, 0, signo
) < 0)
1414 int save_errno
= errno
;
1416 /* We know the thread exists, so ESRCH must mean the lwp is
1417 zombie. This can happen if one of the already-detached
1418 threads exits the whole thread group. In that case we're
1419 still attached, and must reap the lwp. */
1420 if (save_errno
== ESRCH
)
1424 ret
= my_waitpid (lwpid
, &status
, __WALL
);
1427 warning (_("Couldn't reap LWP %d while detaching: %s"),
1428 lwpid
, safe_strerror (errno
));
1430 else if (!WIFEXITED (status
) && !WIFSIGNALED (status
))
1432 warning (_("Reaping LWP %d while detaching "
1433 "returned unexpected status 0x%x"),
1439 error (_("Can't detach %s: %s"),
1440 target_pid_to_str (lp
->ptid
).c_str (),
1441 safe_strerror (save_errno
));
1444 else if (debug_linux_nat
)
1446 fprintf_unfiltered (gdb_stdlog
,
1447 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1448 target_pid_to_str (lp
->ptid
).c_str (),
1452 delete_lwp (lp
->ptid
);
1456 detach_callback (struct lwp_info
*lp
)
1458 /* We don't actually detach from the thread group leader just yet.
1459 If the thread group exits, we must reap the zombie clone lwps
1460 before we're able to reap the leader. */
1461 if (lp
->ptid
.lwp () != lp
->ptid
.pid ())
1462 detach_one_lwp (lp
, NULL
);
1467 linux_nat_target::detach (inferior
*inf
, int from_tty
)
1469 struct lwp_info
*main_lwp
;
1472 /* Don't unregister from the event loop, as there may be other
1473 inferiors running. */
1475 /* Stop all threads before detaching. ptrace requires that the
1476 thread is stopped to successfully detach. */
1477 iterate_over_lwps (ptid_t (pid
), stop_callback
);
1478 /* ... and wait until all of them have reported back that
1479 they're no longer running. */
1480 iterate_over_lwps (ptid_t (pid
), stop_wait_callback
);
1482 iterate_over_lwps (ptid_t (pid
), detach_callback
);
1484 /* Only the initial process should be left right now. */
1485 gdb_assert (num_lwps (pid
) == 1);
1487 main_lwp
= find_lwp_pid (ptid_t (pid
));
1489 if (forks_exist_p ())
1491 /* Multi-fork case. The current inferior_ptid is being detached
1492 from, but there are other viable forks to debug. Detach from
1493 the current fork, and context-switch to the first
1495 linux_fork_detach (from_tty
);
1499 target_announce_detach (from_tty
);
1501 /* Pass on any pending signal for the last LWP. */
1502 int signo
= get_detach_signal (main_lwp
);
1504 detach_one_lwp (main_lwp
, &signo
);
1506 detach_success (inf
);
1510 /* Resume execution of the inferior process. If STEP is nonzero,
1511 single-step it. If SIGNAL is nonzero, give it that signal. */
1514 linux_resume_one_lwp_throw (struct lwp_info
*lp
, int step
,
1515 enum gdb_signal signo
)
1519 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1520 We only presently need that if the LWP is stepped though (to
1521 handle the case of stepping a breakpoint instruction). */
1524 struct regcache
*regcache
= get_thread_regcache (linux_target
, lp
->ptid
);
1526 lp
->stop_pc
= regcache_read_pc (regcache
);
1531 linux_target
->low_prepare_to_resume (lp
);
1532 linux_target
->low_resume (lp
->ptid
, step
, signo
);
1534 /* Successfully resumed. Clear state that no longer makes sense,
1535 and mark the LWP as running. Must not do this before resuming
1536 otherwise if that fails other code will be confused. E.g., we'd
1537 later try to stop the LWP and hang forever waiting for a stop
1538 status. Note that we must not throw after this is cleared,
1539 otherwise handle_zombie_lwp_error would get confused. */
1542 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1543 registers_changed_ptid (linux_target
, lp
->ptid
);
1546 /* Called when we try to resume a stopped LWP and that errors out. If
1547 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1548 or about to become), discard the error, clear any pending status
1549 the LWP may have, and return true (we'll collect the exit status
1550 soon enough). Otherwise, return false. */
1553 check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
)
1555 /* If we get an error after resuming the LWP successfully, we'd
1556 confuse !T state for the LWP being gone. */
1557 gdb_assert (lp
->stopped
);
1559 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1560 because even if ptrace failed with ESRCH, the tracee may be "not
1561 yet fully dead", but already refusing ptrace requests. In that
1562 case the tracee has 'R (Running)' state for a little bit
1563 (observed in Linux 3.18). See also the note on ESRCH in the
1564 ptrace(2) man page. Instead, check whether the LWP has any state
1565 other than ptrace-stopped. */
1567 /* Don't assume anything if /proc/PID/status can't be read. */
1568 if (linux_proc_pid_is_trace_stopped_nowarn (lp
->ptid
.lwp ()) == 0)
1570 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1572 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
1578 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1579 disappears while we try to resume it. */
1582 linux_resume_one_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1586 linux_resume_one_lwp_throw (lp
, step
, signo
);
1588 catch (const gdb_exception_error
&ex
)
1590 if (!check_ptrace_stopped_lwp_gone (lp
))
1598 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1602 struct inferior
*inf
= find_inferior_ptid (linux_target
, lp
->ptid
);
1604 if (inf
->vfork_child
!= NULL
)
1606 if (debug_linux_nat
)
1607 fprintf_unfiltered (gdb_stdlog
,
1608 "RC: Not resuming %s (vfork parent)\n",
1609 target_pid_to_str (lp
->ptid
).c_str ());
1611 else if (!lwp_status_pending_p (lp
))
1613 if (debug_linux_nat
)
1614 fprintf_unfiltered (gdb_stdlog
,
1615 "RC: Resuming sibling %s, %s, %s\n",
1616 target_pid_to_str (lp
->ptid
).c_str (),
1617 (signo
!= GDB_SIGNAL_0
1618 ? strsignal (gdb_signal_to_host (signo
))
1620 step
? "step" : "resume");
1622 linux_resume_one_lwp (lp
, step
, signo
);
1626 if (debug_linux_nat
)
1627 fprintf_unfiltered (gdb_stdlog
,
1628 "RC: Not resuming sibling %s (has pending)\n",
1629 target_pid_to_str (lp
->ptid
).c_str ());
1634 if (debug_linux_nat
)
1635 fprintf_unfiltered (gdb_stdlog
,
1636 "RC: Not resuming sibling %s (not stopped)\n",
1637 target_pid_to_str (lp
->ptid
).c_str ());
1641 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1642 Resume LWP with the last stop signal, if it is in pass state. */
1645 linux_nat_resume_callback (struct lwp_info
*lp
, struct lwp_info
*except
)
1647 enum gdb_signal signo
= GDB_SIGNAL_0
;
1654 struct thread_info
*thread
;
1656 thread
= find_thread_ptid (linux_target
, lp
->ptid
);
1659 signo
= thread
->suspend
.stop_signal
;
1660 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1664 resume_lwp (lp
, 0, signo
);
1669 resume_clear_callback (struct lwp_info
*lp
)
1672 lp
->last_resume_kind
= resume_stop
;
1677 resume_set_callback (struct lwp_info
*lp
)
1680 lp
->last_resume_kind
= resume_continue
;
1685 linux_nat_target::resume (ptid_t ptid
, int step
, enum gdb_signal signo
)
1687 struct lwp_info
*lp
;
1690 if (debug_linux_nat
)
1691 fprintf_unfiltered (gdb_stdlog
,
1692 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1693 step
? "step" : "resume",
1694 target_pid_to_str (ptid
).c_str (),
1695 (signo
!= GDB_SIGNAL_0
1696 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1697 target_pid_to_str (inferior_ptid
).c_str ());
1699 /* A specific PTID means `step only this process id'. */
1700 resume_many
= (minus_one_ptid
== ptid
1703 /* Mark the lwps we're resuming as resumed. */
1704 iterate_over_lwps (ptid
, resume_set_callback
);
1706 /* See if it's the current inferior that should be handled
1709 lp
= find_lwp_pid (inferior_ptid
);
1711 lp
= find_lwp_pid (ptid
);
1712 gdb_assert (lp
!= NULL
);
1714 /* Remember if we're stepping. */
1715 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1717 /* If we have a pending wait status for this thread, there is no
1718 point in resuming the process. But first make sure that
1719 linux_nat_wait won't preemptively handle the event - we
1720 should never take this short-circuit if we are going to
1721 leave LP running, since we have skipped resuming all the
1722 other threads. This bit of code needs to be synchronized
1723 with linux_nat_wait. */
1725 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1728 && WSTOPSIG (lp
->status
)
1729 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1731 if (debug_linux_nat
)
1732 fprintf_unfiltered (gdb_stdlog
,
1733 "LLR: Not short circuiting for ignored "
1734 "status 0x%x\n", lp
->status
);
1736 /* FIXME: What should we do if we are supposed to continue
1737 this thread with a signal? */
1738 gdb_assert (signo
== GDB_SIGNAL_0
);
1739 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1744 if (lwp_status_pending_p (lp
))
1746 /* FIXME: What should we do if we are supposed to continue
1747 this thread with a signal? */
1748 gdb_assert (signo
== GDB_SIGNAL_0
);
1750 if (debug_linux_nat
)
1751 fprintf_unfiltered (gdb_stdlog
,
1752 "LLR: Short circuiting for status 0x%x\n",
1755 if (target_can_async_p ())
1758 /* Tell the event loop we have something to process. */
1765 iterate_over_lwps (ptid
, [=] (struct lwp_info
*info
)
1767 return linux_nat_resume_callback (info
, lp
);
1770 if (debug_linux_nat
)
1771 fprintf_unfiltered (gdb_stdlog
,
1772 "LLR: %s %s, %s (resume event thread)\n",
1773 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1774 target_pid_to_str (lp
->ptid
).c_str (),
1775 (signo
!= GDB_SIGNAL_0
1776 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1778 linux_resume_one_lwp (lp
, step
, signo
);
1780 if (target_can_async_p ())
1784 /* Send a signal to an LWP. */
1787 kill_lwp (int lwpid
, int signo
)
1792 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1793 if (errno
== ENOSYS
)
1795 /* If tkill fails, then we are not using nptl threads, a
1796 configuration we no longer support. */
1797 perror_with_name (("tkill"));
1802 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1803 event, check if the core is interested in it: if not, ignore the
1804 event, and keep waiting; otherwise, we need to toggle the LWP's
1805 syscall entry/exit status, since the ptrace event itself doesn't
1806 indicate it, and report the trap to higher layers. */
1809 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1811 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1812 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1813 thread_info
*thread
= find_thread_ptid (linux_target
, lp
->ptid
);
1814 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, thread
);
1818 /* If we're stopping threads, there's a SIGSTOP pending, which
1819 makes it so that the LWP reports an immediate syscall return,
1820 followed by the SIGSTOP. Skip seeing that "return" using
1821 PTRACE_CONT directly, and let stop_wait_callback collect the
1822 SIGSTOP. Later when the thread is resumed, a new syscall
1823 entry event. If we didn't do this (and returned 0), we'd
1824 leave a syscall entry pending, and our caller, by using
1825 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1826 itself. Later, when the user re-resumes this LWP, we'd see
1827 another syscall entry event and we'd mistake it for a return.
1829 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1830 (leaving immediately with LWP->signalled set, without issuing
1831 a PTRACE_CONT), it would still be problematic to leave this
1832 syscall enter pending, as later when the thread is resumed,
1833 it would then see the same syscall exit mentioned above,
1834 followed by the delayed SIGSTOP, while the syscall didn't
1835 actually get to execute. It seems it would be even more
1836 confusing to the user. */
1838 if (debug_linux_nat
)
1839 fprintf_unfiltered (gdb_stdlog
,
1840 "LHST: ignoring syscall %d "
1841 "for LWP %ld (stopping threads), "
1842 "resuming with PTRACE_CONT for SIGSTOP\n",
1846 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1847 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
1852 /* Always update the entry/return state, even if this particular
1853 syscall isn't interesting to the core now. In async mode,
1854 the user could install a new catchpoint for this syscall
1855 between syscall enter/return, and we'll need to know to
1856 report a syscall return if that happens. */
1857 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1858 ? TARGET_WAITKIND_SYSCALL_RETURN
1859 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1861 if (catch_syscall_enabled ())
1863 if (catching_syscall_number (syscall_number
))
1865 /* Alright, an event to report. */
1866 ourstatus
->kind
= lp
->syscall_state
;
1867 ourstatus
->value
.syscall_number
= syscall_number
;
1869 if (debug_linux_nat
)
1870 fprintf_unfiltered (gdb_stdlog
,
1871 "LHST: stopping for %s of syscall %d"
1874 == TARGET_WAITKIND_SYSCALL_ENTRY
1875 ? "entry" : "return",
1881 if (debug_linux_nat
)
1882 fprintf_unfiltered (gdb_stdlog
,
1883 "LHST: ignoring %s of syscall %d "
1885 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1886 ? "entry" : "return",
1892 /* If we had been syscall tracing, and hence used PT_SYSCALL
1893 before on this LWP, it could happen that the user removes all
1894 syscall catchpoints before we get to process this event.
1895 There are two noteworthy issues here:
1897 - When stopped at a syscall entry event, resuming with
1898 PT_STEP still resumes executing the syscall and reports a
1901 - Only PT_SYSCALL catches syscall enters. If we last
1902 single-stepped this thread, then this event can't be a
1903 syscall enter. If we last single-stepped this thread, this
1904 has to be a syscall exit.
1906 The points above mean that the next resume, be it PT_STEP or
1907 PT_CONTINUE, can not trigger a syscall trace event. */
1908 if (debug_linux_nat
)
1909 fprintf_unfiltered (gdb_stdlog
,
1910 "LHST: caught syscall event "
1911 "with no syscall catchpoints."
1912 " %d for LWP %ld, ignoring\n",
1915 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1918 /* The core isn't interested in this event. For efficiency, avoid
1919 stopping all threads only to have the core resume them all again.
1920 Since we're not stopping threads, if we're still syscall tracing
1921 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1922 subsequent syscall. Simply resume using the inf-ptrace layer,
1923 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1925 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
1929 /* Handle a GNU/Linux extended wait response. If we see a clone
1930 event, we need to add the new LWP to our list (and not report the
1931 trap to higher layers). This function returns non-zero if the
1932 event should be ignored and we should wait again. If STOPPING is
1933 true, the new LWP remains stopped, otherwise it is continued. */
1936 linux_handle_extended_wait (struct lwp_info
*lp
, int status
)
1938 int pid
= lp
->ptid
.lwp ();
1939 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1940 int event
= linux_ptrace_get_extended_event (status
);
1942 /* All extended events we currently use are mid-syscall. Only
1943 PTRACE_EVENT_STOP is delivered more like a signal-stop, but
1944 you have to be using PTRACE_SEIZE to get that. */
1945 lp
->syscall_state
= TARGET_WAITKIND_SYSCALL_ENTRY
;
1947 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1948 || event
== PTRACE_EVENT_CLONE
)
1950 unsigned long new_pid
;
1953 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1955 /* If we haven't already seen the new PID stop, wait for it now. */
1956 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1958 /* The new child has a pending SIGSTOP. We can't affect it until it
1959 hits the SIGSTOP, but we're already attached. */
1960 ret
= my_waitpid (new_pid
, &status
, __WALL
);
1962 perror_with_name (_("waiting for new child"));
1963 else if (ret
!= new_pid
)
1964 internal_error (__FILE__
, __LINE__
,
1965 _("wait returned unexpected PID %d"), ret
);
1966 else if (!WIFSTOPPED (status
))
1967 internal_error (__FILE__
, __LINE__
,
1968 _("wait returned unexpected status 0x%x"), status
);
1971 ourstatus
->value
.related_pid
= ptid_t (new_pid
, new_pid
, 0);
1973 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
1975 /* The arch-specific native code may need to know about new
1976 forks even if those end up never mapped to an
1978 linux_target
->low_new_fork (lp
, new_pid
);
1981 if (event
== PTRACE_EVENT_FORK
1982 && linux_fork_checkpointing_p (lp
->ptid
.pid ()))
1984 /* Handle checkpointing by linux-fork.c here as a special
1985 case. We don't want the follow-fork-mode or 'catch fork'
1986 to interfere with this. */
1988 /* This won't actually modify the breakpoint list, but will
1989 physically remove the breakpoints from the child. */
1990 detach_breakpoints (ptid_t (new_pid
, new_pid
, 0));
1992 /* Retain child fork in ptrace (stopped) state. */
1993 if (!find_fork_pid (new_pid
))
1996 /* Report as spurious, so that infrun doesn't want to follow
1997 this fork. We're actually doing an infcall in
1999 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
2001 /* Report the stop to the core. */
2005 if (event
== PTRACE_EVENT_FORK
)
2006 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
2007 else if (event
== PTRACE_EVENT_VFORK
)
2008 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
2009 else if (event
== PTRACE_EVENT_CLONE
)
2011 struct lwp_info
*new_lp
;
2013 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2015 if (debug_linux_nat
)
2016 fprintf_unfiltered (gdb_stdlog
,
2017 "LHEW: Got clone event "
2018 "from LWP %d, new child is LWP %ld\n",
2021 new_lp
= add_lwp (ptid_t (lp
->ptid
.pid (), new_pid
, 0));
2022 new_lp
->stopped
= 1;
2023 new_lp
->resumed
= 1;
2025 /* If the thread_db layer is active, let it record the user
2026 level thread id and status, and add the thread to GDB's
2028 if (!thread_db_notice_clone (lp
->ptid
, new_lp
->ptid
))
2030 /* The process is not using thread_db. Add the LWP to
2032 target_post_attach (new_lp
->ptid
.lwp ());
2033 add_thread (linux_target
, new_lp
->ptid
);
2036 /* Even if we're stopping the thread for some reason
2037 internal to this module, from the perspective of infrun
2038 and the user/frontend, this new thread is running until
2039 it next reports a stop. */
2040 set_running (linux_target
, new_lp
->ptid
, 1);
2041 set_executing (linux_target
, new_lp
->ptid
, 1);
2043 if (WSTOPSIG (status
) != SIGSTOP
)
2045 /* This can happen if someone starts sending signals to
2046 the new thread before it gets a chance to run, which
2047 have a lower number than SIGSTOP (e.g. SIGUSR1).
2048 This is an unlikely case, and harder to handle for
2049 fork / vfork than for clone, so we do not try - but
2050 we handle it for clone events here. */
2052 new_lp
->signalled
= 1;
2054 /* We created NEW_LP so it cannot yet contain STATUS. */
2055 gdb_assert (new_lp
->status
== 0);
2057 /* Save the wait status to report later. */
2058 if (debug_linux_nat
)
2059 fprintf_unfiltered (gdb_stdlog
,
2060 "LHEW: waitpid of new LWP %ld, "
2061 "saving status %s\n",
2062 (long) new_lp
->ptid
.lwp (),
2063 status_to_str (status
));
2064 new_lp
->status
= status
;
2066 else if (report_thread_events
)
2068 new_lp
->waitstatus
.kind
= TARGET_WAITKIND_THREAD_CREATED
;
2069 new_lp
->status
= status
;
2078 if (event
== PTRACE_EVENT_EXEC
)
2080 if (debug_linux_nat
)
2081 fprintf_unfiltered (gdb_stdlog
,
2082 "LHEW: Got exec event from LWP %ld\n",
2085 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2086 ourstatus
->value
.execd_pathname
2087 = xstrdup (linux_proc_pid_to_exec_file (pid
));
2089 /* The thread that execed must have been resumed, but, when a
2090 thread execs, it changes its tid to the tgid, and the old
2091 tgid thread might have not been resumed. */
2096 if (event
== PTRACE_EVENT_VFORK_DONE
)
2098 if (current_inferior ()->waiting_for_vfork_done
)
2100 if (debug_linux_nat
)
2101 fprintf_unfiltered (gdb_stdlog
,
2102 "LHEW: Got expected PTRACE_EVENT_"
2103 "VFORK_DONE from LWP %ld: stopping\n",
2106 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2110 if (debug_linux_nat
)
2111 fprintf_unfiltered (gdb_stdlog
,
2112 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2113 "from LWP %ld: ignoring\n",
2118 internal_error (__FILE__
, __LINE__
,
2119 _("unknown ptrace event %d"), event
);
2122 /* Suspend waiting for a signal. We're mostly interested in
2128 if (debug_linux_nat
)
2129 fprintf_unfiltered (gdb_stdlog
, "linux-nat: about to sigsuspend\n");
2130 sigsuspend (&suspend_mask
);
2132 /* If the quit flag is set, it means that the user pressed Ctrl-C
2133 and we're debugging a process that is running on a separate
2134 terminal, so we must forward the Ctrl-C to the inferior. (If the
2135 inferior is sharing GDB's terminal, then the Ctrl-C reaches the
2136 inferior directly.) We must do this here because functions that
2137 need to block waiting for a signal loop forever until there's an
2138 event to report before returning back to the event loop. */
2139 if (!target_terminal::is_ours ())
2141 if (check_quit_flag ())
2142 target_pass_ctrlc ();
2146 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2150 wait_lwp (struct lwp_info
*lp
)
2154 int thread_dead
= 0;
2157 gdb_assert (!lp
->stopped
);
2158 gdb_assert (lp
->status
== 0);
2160 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2161 block_child_signals (&prev_mask
);
2165 pid
= my_waitpid (lp
->ptid
.lwp (), &status
, __WALL
| WNOHANG
);
2166 if (pid
== -1 && errno
== ECHILD
)
2168 /* The thread has previously exited. We need to delete it
2169 now because if this was a non-leader thread execing, we
2170 won't get an exit event. See comments on exec events at
2171 the top of the file. */
2173 if (debug_linux_nat
)
2174 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2175 target_pid_to_str (lp
->ptid
).c_str ());
2180 /* Bugs 10970, 12702.
2181 Thread group leader may have exited in which case we'll lock up in
2182 waitpid if there are other threads, even if they are all zombies too.
2183 Basically, we're not supposed to use waitpid this way.
2184 tkill(pid,0) cannot be used here as it gets ESRCH for both
2185 for zombie and running processes.
2187 As a workaround, check if we're waiting for the thread group leader and
2188 if it's a zombie, and avoid calling waitpid if it is.
2190 This is racy, what if the tgl becomes a zombie right after we check?
2191 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2192 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2194 if (lp
->ptid
.pid () == lp
->ptid
.lwp ()
2195 && linux_proc_pid_is_zombie (lp
->ptid
.lwp ()))
2198 if (debug_linux_nat
)
2199 fprintf_unfiltered (gdb_stdlog
,
2200 "WL: Thread group leader %s vanished.\n",
2201 target_pid_to_str (lp
->ptid
).c_str ());
2205 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2206 get invoked despite our caller had them intentionally blocked by
2207 block_child_signals. This is sensitive only to the loop of
2208 linux_nat_wait_1 and there if we get called my_waitpid gets called
2209 again before it gets to sigsuspend so we can safely let the handlers
2210 get executed here. */
2214 restore_child_signals_mask (&prev_mask
);
2218 gdb_assert (pid
== lp
->ptid
.lwp ());
2220 if (debug_linux_nat
)
2222 fprintf_unfiltered (gdb_stdlog
,
2223 "WL: waitpid %s received %s\n",
2224 target_pid_to_str (lp
->ptid
).c_str (),
2225 status_to_str (status
));
2228 /* Check if the thread has exited. */
2229 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2231 if (report_thread_events
2232 || lp
->ptid
.pid () == lp
->ptid
.lwp ())
2234 if (debug_linux_nat
)
2235 fprintf_unfiltered (gdb_stdlog
, "WL: LWP %d exited.\n",
2238 /* If this is the leader exiting, it means the whole
2239 process is gone. Store the status to report to the
2240 core. Store it in lp->waitstatus, because lp->status
2241 would be ambiguous (W_EXITCODE(0,0) == 0). */
2242 store_waitstatus (&lp
->waitstatus
, status
);
2247 if (debug_linux_nat
)
2248 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2249 target_pid_to_str (lp
->ptid
).c_str ());
2259 gdb_assert (WIFSTOPPED (status
));
2262 if (lp
->must_set_ptrace_flags
)
2264 inferior
*inf
= find_inferior_pid (linux_target
, lp
->ptid
.pid ());
2265 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2267 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2268 lp
->must_set_ptrace_flags
= 0;
2271 /* Handle GNU/Linux's syscall SIGTRAPs. */
2272 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2274 /* No longer need the sysgood bit. The ptrace event ends up
2275 recorded in lp->waitstatus if we care for it. We can carry
2276 on handling the event like a regular SIGTRAP from here
2278 status
= W_STOPCODE (SIGTRAP
);
2279 if (linux_handle_syscall_trap (lp
, 1))
2280 return wait_lwp (lp
);
2284 /* Almost all other ptrace-stops are known to be outside of system
2285 calls, with further exceptions in linux_handle_extended_wait. */
2286 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
2289 /* Handle GNU/Linux's extended waitstatus for trace events. */
2290 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2291 && linux_is_extended_waitstatus (status
))
2293 if (debug_linux_nat
)
2294 fprintf_unfiltered (gdb_stdlog
,
2295 "WL: Handling extended status 0x%06x\n",
2297 linux_handle_extended_wait (lp
, status
);
2304 /* Send a SIGSTOP to LP. */
2307 stop_callback (struct lwp_info
*lp
)
2309 if (!lp
->stopped
&& !lp
->signalled
)
2313 if (debug_linux_nat
)
2315 fprintf_unfiltered (gdb_stdlog
,
2316 "SC: kill %s **<SIGSTOP>**\n",
2317 target_pid_to_str (lp
->ptid
).c_str ());
2320 ret
= kill_lwp (lp
->ptid
.lwp (), SIGSTOP
);
2321 if (debug_linux_nat
)
2323 fprintf_unfiltered (gdb_stdlog
,
2324 "SC: lwp kill %d %s\n",
2326 errno
? safe_strerror (errno
) : "ERRNO-OK");
2330 gdb_assert (lp
->status
== 0);
2336 /* Request a stop on LWP. */
2339 linux_stop_lwp (struct lwp_info
*lwp
)
2341 stop_callback (lwp
);
2344 /* See linux-nat.h */
2347 linux_stop_and_wait_all_lwps (void)
2349 /* Stop all LWP's ... */
2350 iterate_over_lwps (minus_one_ptid
, stop_callback
);
2352 /* ... and wait until all of them have reported back that
2353 they're no longer running. */
2354 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
);
2357 /* See linux-nat.h */
2360 linux_unstop_all_lwps (void)
2362 iterate_over_lwps (minus_one_ptid
,
2363 [] (struct lwp_info
*info
)
2365 return resume_stopped_resumed_lwps (info
, minus_one_ptid
);
2369 /* Return non-zero if LWP PID has a pending SIGINT. */
2372 linux_nat_has_pending_sigint (int pid
)
2374 sigset_t pending
, blocked
, ignored
;
2376 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2378 if (sigismember (&pending
, SIGINT
)
2379 && !sigismember (&ignored
, SIGINT
))
2385 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2388 set_ignore_sigint (struct lwp_info
*lp
)
2390 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2391 flag to consume the next one. */
2392 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2393 && WSTOPSIG (lp
->status
) == SIGINT
)
2396 lp
->ignore_sigint
= 1;
2401 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2402 This function is called after we know the LWP has stopped; if the LWP
2403 stopped before the expected SIGINT was delivered, then it will never have
2404 arrived. Also, if the signal was delivered to a shared queue and consumed
2405 by a different thread, it will never be delivered to this LWP. */
2408 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2410 if (!lp
->ignore_sigint
)
2413 if (!linux_nat_has_pending_sigint (lp
->ptid
.lwp ()))
2415 if (debug_linux_nat
)
2416 fprintf_unfiltered (gdb_stdlog
,
2417 "MCIS: Clearing bogus flag for %s\n",
2418 target_pid_to_str (lp
->ptid
).c_str ());
2419 lp
->ignore_sigint
= 0;
2423 /* Fetch the possible triggered data watchpoint info and store it in
2426 On some archs, like x86, that use debug registers to set
2427 watchpoints, it's possible that the way to know which watched
2428 address trapped, is to check the register that is used to select
2429 which address to watch. Problem is, between setting the watchpoint
2430 and reading back which data address trapped, the user may change
2431 the set of watchpoints, and, as a consequence, GDB changes the
2432 debug registers in the inferior. To avoid reading back a stale
2433 stopped-data-address when that happens, we cache in LP the fact
2434 that a watchpoint trapped, and the corresponding data address, as
2435 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2436 registers meanwhile, we have the cached data we can rely on. */
2439 check_stopped_by_watchpoint (struct lwp_info
*lp
)
2441 scoped_restore save_inferior_ptid
= make_scoped_restore (&inferior_ptid
);
2442 inferior_ptid
= lp
->ptid
;
2444 if (linux_target
->low_stopped_by_watchpoint ())
2446 lp
->stop_reason
= TARGET_STOPPED_BY_WATCHPOINT
;
2447 lp
->stopped_data_address_p
2448 = linux_target
->low_stopped_data_address (&lp
->stopped_data_address
);
2451 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2454 /* Returns true if the LWP had stopped for a watchpoint. */
2457 linux_nat_target::stopped_by_watchpoint ()
2459 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2461 gdb_assert (lp
!= NULL
);
2463 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2467 linux_nat_target::stopped_data_address (CORE_ADDR
*addr_p
)
2469 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2471 gdb_assert (lp
!= NULL
);
2473 *addr_p
= lp
->stopped_data_address
;
2475 return lp
->stopped_data_address_p
;
2478 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2481 linux_nat_target::low_status_is_event (int status
)
2483 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2486 /* Wait until LP is stopped. */
2489 stop_wait_callback (struct lwp_info
*lp
)
2491 inferior
*inf
= find_inferior_ptid (linux_target
, lp
->ptid
);
2493 /* If this is a vfork parent, bail out, it is not going to report
2494 any SIGSTOP until the vfork is done with. */
2495 if (inf
->vfork_child
!= NULL
)
2502 status
= wait_lwp (lp
);
2506 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2507 && WSTOPSIG (status
) == SIGINT
)
2509 lp
->ignore_sigint
= 0;
2512 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
2514 if (debug_linux_nat
)
2515 fprintf_unfiltered (gdb_stdlog
,
2516 "PTRACE_CONT %s, 0, 0 (%s) "
2517 "(discarding SIGINT)\n",
2518 target_pid_to_str (lp
->ptid
).c_str (),
2519 errno
? safe_strerror (errno
) : "OK");
2521 return stop_wait_callback (lp
);
2524 maybe_clear_ignore_sigint (lp
);
2526 if (WSTOPSIG (status
) != SIGSTOP
)
2528 /* The thread was stopped with a signal other than SIGSTOP. */
2530 if (debug_linux_nat
)
2531 fprintf_unfiltered (gdb_stdlog
,
2532 "SWC: Pending event %s in %s\n",
2533 status_to_str ((int) status
),
2534 target_pid_to_str (lp
->ptid
).c_str ());
2536 /* Save the sigtrap event. */
2537 lp
->status
= status
;
2538 gdb_assert (lp
->signalled
);
2539 save_stop_reason (lp
);
2543 /* We caught the SIGSTOP that we intended to catch. */
2545 if (debug_linux_nat
)
2546 fprintf_unfiltered (gdb_stdlog
,
2547 "SWC: Expected SIGSTOP caught for %s.\n",
2548 target_pid_to_str (lp
->ptid
).c_str ());
2552 /* If we are waiting for this stop so we can report the thread
2553 stopped then we need to record this status. Otherwise, we can
2554 now discard this stop event. */
2555 if (lp
->last_resume_kind
== resume_stop
)
2557 lp
->status
= status
;
2558 save_stop_reason (lp
);
2566 /* Return non-zero if LP has a wait status pending. Discard the
2567 pending event and resume the LWP if the event that originally
2568 caused the stop became uninteresting. */
2571 status_callback (struct lwp_info
*lp
)
2573 /* Only report a pending wait status if we pretend that this has
2574 indeed been resumed. */
2578 if (!lwp_status_pending_p (lp
))
2581 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
2582 || lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2584 struct regcache
*regcache
= get_thread_regcache (linux_target
, lp
->ptid
);
2588 pc
= regcache_read_pc (regcache
);
2590 if (pc
!= lp
->stop_pc
)
2592 if (debug_linux_nat
)
2593 fprintf_unfiltered (gdb_stdlog
,
2594 "SC: PC of %s changed. was=%s, now=%s\n",
2595 target_pid_to_str (lp
->ptid
).c_str (),
2596 paddress (target_gdbarch (), lp
->stop_pc
),
2597 paddress (target_gdbarch (), pc
));
2601 #if !USE_SIGTRAP_SIGINFO
2602 else if (!breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2604 if (debug_linux_nat
)
2605 fprintf_unfiltered (gdb_stdlog
,
2606 "SC: previous breakpoint of %s, at %s gone\n",
2607 target_pid_to_str (lp
->ptid
).c_str (),
2608 paddress (target_gdbarch (), lp
->stop_pc
));
2616 if (debug_linux_nat
)
2617 fprintf_unfiltered (gdb_stdlog
,
2618 "SC: pending event of %s cancelled.\n",
2619 target_pid_to_str (lp
->ptid
).c_str ());
2622 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2630 /* Count the LWP's that have had events. */
2633 count_events_callback (struct lwp_info
*lp
, int *count
)
2635 gdb_assert (count
!= NULL
);
2637 /* Select only resumed LWPs that have an event pending. */
2638 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2644 /* Select the LWP (if any) that is currently being single-stepped. */
2647 select_singlestep_lwp_callback (struct lwp_info
*lp
)
2649 if (lp
->last_resume_kind
== resume_step
2656 /* Returns true if LP has a status pending. */
2659 lwp_status_pending_p (struct lwp_info
*lp
)
2661 /* We check for lp->waitstatus in addition to lp->status, because we
2662 can have pending process exits recorded in lp->status and
2663 W_EXITCODE(0,0) happens to be 0. */
2664 return lp
->status
!= 0 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
;
2667 /* Select the Nth LWP that has had an event. */
2670 select_event_lwp_callback (struct lwp_info
*lp
, int *selector
)
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 (linux_target
, 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
).c_str ());
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
).c_str ());
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
).c_str ());
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
).c_str ());
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
, select_singlestep_lwp_callback
);
2871 if (event_lp
!= NULL
)
2873 if (debug_linux_nat
)
2874 fprintf_unfiltered (gdb_stdlog
,
2875 "SEL: Select single-step %s\n",
2876 target_pid_to_str (event_lp
->ptid
).c_str ());
2880 if (event_lp
== NULL
)
2882 /* Pick one at random, out of those which have had events. */
2884 /* First see how many events we have. */
2885 iterate_over_lwps (filter
,
2886 [&] (struct lwp_info
*info
)
2888 return count_events_callback (info
, &num_events
);
2890 gdb_assert (num_events
> 0);
2892 /* Now randomly pick a LWP out of those that have had
2894 random_selector
= (int)
2895 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2897 if (debug_linux_nat
&& num_events
> 1)
2898 fprintf_unfiltered (gdb_stdlog
,
2899 "SEL: Found %d events, selecting #%d\n",
2900 num_events
, random_selector
);
2903 = (iterate_over_lwps
2905 [&] (struct lwp_info
*info
)
2907 return select_event_lwp_callback (info
,
2912 if (event_lp
!= NULL
)
2914 /* Switch the event LWP. */
2915 *orig_lp
= event_lp
;
2916 *status
= event_lp
->status
;
2919 /* Flush the wait status for the event LWP. */
2920 (*orig_lp
)->status
= 0;
2923 /* Return non-zero if LP has been resumed. */
2926 resumed_callback (struct lwp_info
*lp
)
2931 /* Check if we should go on and pass this event to common code.
2932 Return the affected lwp if we are, or NULL otherwise. */
2934 static struct lwp_info
*
2935 linux_nat_filter_event (int lwpid
, int status
)
2937 struct lwp_info
*lp
;
2938 int event
= linux_ptrace_get_extended_event (status
);
2940 lp
= find_lwp_pid (ptid_t (lwpid
));
2942 /* Check for stop events reported by a process we didn't already
2943 know about - anything not already in our LWP list.
2945 If we're expecting to receive stopped processes after
2946 fork, vfork, and clone events, then we'll just add the
2947 new one to our list and go back to waiting for the event
2948 to be reported - the stopped process might be returned
2949 from waitpid before or after the event is.
2951 But note the case of a non-leader thread exec'ing after the
2952 leader having exited, and gone from our lists. The non-leader
2953 thread changes its tid to the tgid. */
2955 if (WIFSTOPPED (status
) && lp
== NULL
2956 && (WSTOPSIG (status
) == SIGTRAP
&& event
== PTRACE_EVENT_EXEC
))
2958 /* A multi-thread exec after we had seen the leader exiting. */
2959 if (debug_linux_nat
)
2960 fprintf_unfiltered (gdb_stdlog
,
2961 "LLW: Re-adding thread group leader LWP %d.\n",
2964 lp
= add_lwp (ptid_t (lwpid
, lwpid
, 0));
2967 add_thread (linux_target
, lp
->ptid
);
2970 if (WIFSTOPPED (status
) && !lp
)
2972 if (debug_linux_nat
)
2973 fprintf_unfiltered (gdb_stdlog
,
2974 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2975 (long) lwpid
, status_to_str (status
));
2976 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2980 /* Make sure we don't report an event for the exit of an LWP not in
2981 our list, i.e. not part of the current process. This can happen
2982 if we detach from a program we originally forked and then it
2984 if (!WIFSTOPPED (status
) && !lp
)
2987 /* This LWP is stopped now. (And if dead, this prevents it from
2988 ever being continued.) */
2991 if (WIFSTOPPED (status
) && lp
->must_set_ptrace_flags
)
2993 inferior
*inf
= find_inferior_pid (linux_target
, lp
->ptid
.pid ());
2994 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2996 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2997 lp
->must_set_ptrace_flags
= 0;
3000 /* Handle GNU/Linux's syscall SIGTRAPs. */
3001 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
3003 /* No longer need the sysgood bit. The ptrace event ends up
3004 recorded in lp->waitstatus if we care for it. We can carry
3005 on handling the event like a regular SIGTRAP from here
3007 status
= W_STOPCODE (SIGTRAP
);
3008 if (linux_handle_syscall_trap (lp
, 0))
3013 /* Almost all other ptrace-stops are known to be outside of system
3014 calls, with further exceptions in linux_handle_extended_wait. */
3015 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
3018 /* Handle GNU/Linux's extended waitstatus for trace events. */
3019 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
3020 && linux_is_extended_waitstatus (status
))
3022 if (debug_linux_nat
)
3023 fprintf_unfiltered (gdb_stdlog
,
3024 "LLW: Handling extended status 0x%06x\n",
3026 if (linux_handle_extended_wait (lp
, status
))
3030 /* Check if the thread has exited. */
3031 if (WIFEXITED (status
) || WIFSIGNALED (status
))
3033 if (!report_thread_events
3034 && num_lwps (lp
->ptid
.pid ()) > 1)
3036 if (debug_linux_nat
)
3037 fprintf_unfiltered (gdb_stdlog
,
3038 "LLW: %s exited.\n",
3039 target_pid_to_str (lp
->ptid
).c_str ());
3041 /* If there is at least one more LWP, then the exit signal
3042 was not the end of the debugged application and should be
3048 /* Note that even if the leader was ptrace-stopped, it can still
3049 exit, if e.g., some other thread brings down the whole
3050 process (calls `exit'). So don't assert that the lwp is
3052 if (debug_linux_nat
)
3053 fprintf_unfiltered (gdb_stdlog
,
3054 "LWP %ld exited (resumed=%d)\n",
3055 lp
->ptid
.lwp (), lp
->resumed
);
3057 /* Dead LWP's aren't expected to reported a pending sigstop. */
3060 /* Store the pending event in the waitstatus, because
3061 W_EXITCODE(0,0) == 0. */
3062 store_waitstatus (&lp
->waitstatus
, status
);
3066 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3067 an attempt to stop an LWP. */
3069 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3073 if (lp
->last_resume_kind
== resume_stop
)
3075 if (debug_linux_nat
)
3076 fprintf_unfiltered (gdb_stdlog
,
3077 "LLW: resume_stop SIGSTOP caught for %s.\n",
3078 target_pid_to_str (lp
->ptid
).c_str ());
3082 /* This is a delayed SIGSTOP. Filter out the event. */
3084 if (debug_linux_nat
)
3085 fprintf_unfiltered (gdb_stdlog
,
3086 "LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
3088 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3089 target_pid_to_str (lp
->ptid
).c_str ());
3091 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3092 gdb_assert (lp
->resumed
);
3097 /* Make sure we don't report a SIGINT that we have already displayed
3098 for another thread. */
3099 if (lp
->ignore_sigint
3100 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3102 if (debug_linux_nat
)
3103 fprintf_unfiltered (gdb_stdlog
,
3104 "LLW: Delayed SIGINT caught for %s.\n",
3105 target_pid_to_str (lp
->ptid
).c_str ());
3107 /* This is a delayed SIGINT. */
3108 lp
->ignore_sigint
= 0;
3110 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3111 if (debug_linux_nat
)
3112 fprintf_unfiltered (gdb_stdlog
,
3113 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3115 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3116 target_pid_to_str (lp
->ptid
).c_str ());
3117 gdb_assert (lp
->resumed
);
3119 /* Discard the event. */
3123 /* Don't report signals that GDB isn't interested in, such as
3124 signals that are neither printed nor stopped upon. Stopping all
3125 threads can be a bit time-consuming so if we want decent
3126 performance with heavily multi-threaded programs, especially when
3127 they're using a high frequency timer, we'd better avoid it if we
3129 if (WIFSTOPPED (status
))
3131 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3133 if (!target_is_non_stop_p ())
3135 /* Only do the below in all-stop, as we currently use SIGSTOP
3136 to implement target_stop (see linux_nat_stop) in
3138 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3140 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3141 forwarded to the entire process group, that is, all LWPs
3142 will receive it - unless they're using CLONE_THREAD to
3143 share signals. Since we only want to report it once, we
3144 mark it as ignored for all LWPs except this one. */
3145 iterate_over_lwps (ptid_t (lp
->ptid
.pid ()), set_ignore_sigint
);
3146 lp
->ignore_sigint
= 0;
3149 maybe_clear_ignore_sigint (lp
);
3152 /* When using hardware single-step, we need to report every signal.
3153 Otherwise, signals in pass_mask may be short-circuited
3154 except signals that might be caused by a breakpoint, or SIGSTOP
3155 if we sent the SIGSTOP and are waiting for it to arrive. */
3157 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
))
3158 && (WSTOPSIG (status
) != SIGSTOP
3159 || !find_thread_ptid (linux_target
, lp
->ptid
)->stop_requested
)
3160 && !linux_wstatus_maybe_breakpoint (status
))
3162 linux_resume_one_lwp (lp
, lp
->step
, signo
);
3163 if (debug_linux_nat
)
3164 fprintf_unfiltered (gdb_stdlog
,
3165 "LLW: %s %s, %s (preempt 'handle')\n",
3167 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3168 target_pid_to_str (lp
->ptid
).c_str (),
3169 (signo
!= GDB_SIGNAL_0
3170 ? strsignal (gdb_signal_to_host (signo
))
3176 /* An interesting event. */
3178 lp
->status
= status
;
3179 save_stop_reason (lp
);
3183 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3184 their exits until all other threads in the group have exited. */
3187 check_zombie_leaders (void)
3189 for (inferior
*inf
: all_inferiors ())
3191 struct lwp_info
*leader_lp
;
3196 leader_lp
= find_lwp_pid (ptid_t (inf
->pid
));
3197 if (leader_lp
!= NULL
3198 /* Check if there are other threads in the group, as we may
3199 have raced with the inferior simply exiting. */
3200 && num_lwps (inf
->pid
) > 1
3201 && linux_proc_pid_is_zombie (inf
->pid
))
3203 if (debug_linux_nat
)
3204 fprintf_unfiltered (gdb_stdlog
,
3205 "CZL: Thread group leader %d zombie "
3206 "(it exited, or another thread execd).\n",
3209 /* A leader zombie can mean one of two things:
3211 - It exited, and there's an exit status pending
3212 available, or only the leader exited (not the whole
3213 program). In the latter case, we can't waitpid the
3214 leader's exit status until all other threads are gone.
3216 - There are 3 or more threads in the group, and a thread
3217 other than the leader exec'd. See comments on exec
3218 events at the top of the file. We could try
3219 distinguishing the exit and exec cases, by waiting once
3220 more, and seeing if something comes out, but it doesn't
3221 sound useful. The previous leader _does_ go away, and
3222 we'll re-add the new one once we see the exec event
3223 (which is just the same as what would happen if the
3224 previous leader did exit voluntarily before some other
3227 if (debug_linux_nat
)
3228 fprintf_unfiltered (gdb_stdlog
,
3229 "CZL: Thread group leader %d vanished.\n",
3231 exit_lwp (leader_lp
);
3236 /* Convenience function that is called when the kernel reports an exit
3237 event. This decides whether to report the event to GDB as a
3238 process exit event, a thread exit event, or to suppress the
3242 filter_exit_event (struct lwp_info
*event_child
,
3243 struct target_waitstatus
*ourstatus
)
3245 ptid_t ptid
= event_child
->ptid
;
3247 if (num_lwps (ptid
.pid ()) > 1)
3249 if (report_thread_events
)
3250 ourstatus
->kind
= TARGET_WAITKIND_THREAD_EXITED
;
3252 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3254 exit_lwp (event_child
);
3261 linux_nat_wait_1 (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3265 enum resume_kind last_resume_kind
;
3266 struct lwp_info
*lp
;
3269 if (debug_linux_nat
)
3270 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3272 /* The first time we get here after starting a new inferior, we may
3273 not have added it to the LWP list yet - this is the earliest
3274 moment at which we know its PID. */
3275 if (inferior_ptid
.is_pid ())
3277 /* Upgrade the main thread's ptid. */
3278 thread_change_ptid (linux_target
, inferior_ptid
,
3279 ptid_t (inferior_ptid
.pid (),
3280 inferior_ptid
.pid (), 0));
3282 lp
= add_initial_lwp (inferior_ptid
);
3286 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3287 block_child_signals (&prev_mask
);
3289 /* First check if there is a LWP with a wait status pending. */
3290 lp
= iterate_over_lwps (ptid
, status_callback
);
3293 if (debug_linux_nat
)
3294 fprintf_unfiltered (gdb_stdlog
,
3295 "LLW: Using pending wait status %s for %s.\n",
3296 status_to_str (lp
->status
),
3297 target_pid_to_str (lp
->ptid
).c_str ());
3300 /* But if we don't find a pending event, we'll have to wait. Always
3301 pull all events out of the kernel. We'll randomly select an
3302 event LWP out of all that have events, to prevent starvation. */
3308 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3311 - If the thread group leader exits while other threads in the
3312 thread group still exist, waitpid(TGID, ...) hangs. That
3313 waitpid won't return an exit status until the other threads
3314 in the group are reaped.
3316 - When a non-leader thread execs, that thread just vanishes
3317 without reporting an exit (so we'd hang if we waited for it
3318 explicitly in that case). The exec event is reported to
3322 lwpid
= my_waitpid (-1, &status
, __WALL
| WNOHANG
);
3324 if (debug_linux_nat
)
3325 fprintf_unfiltered (gdb_stdlog
,
3326 "LNW: waitpid(-1, ...) returned %d, %s\n",
3327 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3331 if (debug_linux_nat
)
3333 fprintf_unfiltered (gdb_stdlog
,
3334 "LLW: waitpid %ld received %s\n",
3335 (long) lwpid
, status_to_str (status
));
3338 linux_nat_filter_event (lwpid
, status
);
3339 /* Retry until nothing comes out of waitpid. A single
3340 SIGCHLD can indicate more than one child stopped. */
3344 /* Now that we've pulled all events out of the kernel, resume
3345 LWPs that don't have an interesting event to report. */
3346 iterate_over_lwps (minus_one_ptid
,
3347 [] (struct lwp_info
*info
)
3349 return resume_stopped_resumed_lwps (info
, minus_one_ptid
);
3352 /* ... and find an LWP with a status to report to the core, if
3354 lp
= iterate_over_lwps (ptid
, status_callback
);
3358 /* Check for zombie thread group leaders. Those can't be reaped
3359 until all other threads in the thread group are. */
3360 check_zombie_leaders ();
3362 /* If there are no resumed children left, bail. We'd be stuck
3363 forever in the sigsuspend call below otherwise. */
3364 if (iterate_over_lwps (ptid
, resumed_callback
) == NULL
)
3366 if (debug_linux_nat
)
3367 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3369 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3371 restore_child_signals_mask (&prev_mask
);
3372 return minus_one_ptid
;
3375 /* No interesting event to report to the core. */
3377 if (target_options
& TARGET_WNOHANG
)
3379 if (debug_linux_nat
)
3380 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3382 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3383 restore_child_signals_mask (&prev_mask
);
3384 return minus_one_ptid
;
3387 /* We shouldn't end up here unless we want to try again. */
3388 gdb_assert (lp
== NULL
);
3390 /* Block until we get an event reported with SIGCHLD. */
3396 status
= lp
->status
;
3399 if (!target_is_non_stop_p ())
3401 /* Now stop all other LWP's ... */
3402 iterate_over_lwps (minus_one_ptid
, stop_callback
);
3404 /* ... and wait until all of them have reported back that
3405 they're no longer running. */
3406 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
);
3409 /* If we're not waiting for a specific LWP, choose an event LWP from
3410 among those that have had events. Giving equal priority to all
3411 LWPs that have had events helps prevent starvation. */
3412 if (ptid
== minus_one_ptid
|| ptid
.is_pid ())
3413 select_event_lwp (ptid
, &lp
, &status
);
3415 gdb_assert (lp
!= NULL
);
3417 /* Now that we've selected our final event LWP, un-adjust its PC if
3418 it was a software breakpoint, and we can't reliably support the
3419 "stopped by software breakpoint" stop reason. */
3420 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
3421 && !USE_SIGTRAP_SIGINFO
)
3423 struct regcache
*regcache
= get_thread_regcache (linux_target
, lp
->ptid
);
3424 struct gdbarch
*gdbarch
= regcache
->arch ();
3425 int decr_pc
= gdbarch_decr_pc_after_break (gdbarch
);
3431 pc
= regcache_read_pc (regcache
);
3432 regcache_write_pc (regcache
, pc
+ decr_pc
);
3436 /* We'll need this to determine whether to report a SIGSTOP as
3437 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3439 last_resume_kind
= lp
->last_resume_kind
;
3441 if (!target_is_non_stop_p ())
3443 /* In all-stop, from the core's perspective, all LWPs are now
3444 stopped until a new resume action is sent over. */
3445 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
);
3449 resume_clear_callback (lp
);
3452 if (linux_target
->low_status_is_event (status
))
3454 if (debug_linux_nat
)
3455 fprintf_unfiltered (gdb_stdlog
,
3456 "LLW: trap ptid is %s.\n",
3457 target_pid_to_str (lp
->ptid
).c_str ());
3460 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3462 *ourstatus
= lp
->waitstatus
;
3463 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3466 store_waitstatus (ourstatus
, status
);
3468 if (debug_linux_nat
)
3469 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3471 restore_child_signals_mask (&prev_mask
);
3473 if (last_resume_kind
== resume_stop
3474 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3475 && WSTOPSIG (status
) == SIGSTOP
)
3477 /* A thread that has been requested to stop by GDB with
3478 target_stop, and it stopped cleanly, so report as SIG0. The
3479 use of SIGSTOP is an implementation detail. */
3480 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3483 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3484 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3487 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3489 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
)
3490 return filter_exit_event (lp
, ourstatus
);
3495 /* Resume LWPs that are currently stopped without any pending status
3496 to report, but are resumed from the core's perspective. */
3499 resume_stopped_resumed_lwps (struct lwp_info
*lp
, const ptid_t wait_ptid
)
3503 if (debug_linux_nat
)
3504 fprintf_unfiltered (gdb_stdlog
,
3505 "RSRL: NOT resuming LWP %s, not stopped\n",
3506 target_pid_to_str (lp
->ptid
).c_str ());
3508 else if (!lp
->resumed
)
3510 if (debug_linux_nat
)
3511 fprintf_unfiltered (gdb_stdlog
,
3512 "RSRL: NOT resuming LWP %s, not resumed\n",
3513 target_pid_to_str (lp
->ptid
).c_str ());
3515 else if (lwp_status_pending_p (lp
))
3517 if (debug_linux_nat
)
3518 fprintf_unfiltered (gdb_stdlog
,
3519 "RSRL: NOT resuming LWP %s, has pending status\n",
3520 target_pid_to_str (lp
->ptid
).c_str ());
3524 struct regcache
*regcache
= get_thread_regcache (linux_target
, lp
->ptid
);
3525 struct gdbarch
*gdbarch
= regcache
->arch ();
3529 CORE_ADDR pc
= regcache_read_pc (regcache
);
3530 int leave_stopped
= 0;
3532 /* Don't bother if there's a breakpoint at PC that we'd hit
3533 immediately, and we're not waiting for this LWP. */
3534 if (!lp
->ptid
.matches (wait_ptid
))
3536 if (breakpoint_inserted_here_p (regcache
->aspace (), pc
))
3542 if (debug_linux_nat
)
3543 fprintf_unfiltered (gdb_stdlog
,
3544 "RSRL: resuming stopped-resumed LWP %s at "
3546 target_pid_to_str (lp
->ptid
).c_str (),
3547 paddress (gdbarch
, pc
),
3550 linux_resume_one_lwp_throw (lp
, lp
->step
, GDB_SIGNAL_0
);
3553 catch (const gdb_exception_error
&ex
)
3555 if (!check_ptrace_stopped_lwp_gone (lp
))
3564 linux_nat_target::wait (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3569 if (debug_linux_nat
)
3571 std::string options_string
= target_options_to_string (target_options
);
3572 fprintf_unfiltered (gdb_stdlog
,
3573 "linux_nat_wait: [%s], [%s]\n",
3574 target_pid_to_str (ptid
).c_str (),
3575 options_string
.c_str ());
3578 /* Flush the async file first. */
3579 if (target_is_async_p ())
3580 async_file_flush ();
3582 /* Resume LWPs that are currently stopped without any pending status
3583 to report, but are resumed from the core's perspective. LWPs get
3584 in this state if we find them stopping at a time we're not
3585 interested in reporting the event (target_wait on a
3586 specific_process, for example, see linux_nat_wait_1), and
3587 meanwhile the event became uninteresting. Don't bother resuming
3588 LWPs we're not going to wait for if they'd stop immediately. */
3589 if (target_is_non_stop_p ())
3590 iterate_over_lwps (minus_one_ptid
,
3591 [=] (struct lwp_info
*info
)
3593 return resume_stopped_resumed_lwps (info
, ptid
);
3596 event_ptid
= linux_nat_wait_1 (ptid
, ourstatus
, target_options
);
3598 /* If we requested any event, and something came out, assume there
3599 may be more. If we requested a specific lwp or process, also
3600 assume there may be more. */
3601 if (target_is_async_p ()
3602 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3603 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3604 || ptid
!= minus_one_ptid
))
3613 kill_one_lwp (pid_t pid
)
3615 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3618 kill_lwp (pid
, SIGKILL
);
3619 if (debug_linux_nat
)
3621 int save_errno
= errno
;
3623 fprintf_unfiltered (gdb_stdlog
,
3624 "KC: kill (SIGKILL) %ld, 0, 0 (%s)\n", (long) pid
,
3625 save_errno
? safe_strerror (save_errno
) : "OK");
3628 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3631 ptrace (PTRACE_KILL
, pid
, 0, 0);
3632 if (debug_linux_nat
)
3634 int save_errno
= errno
;
3636 fprintf_unfiltered (gdb_stdlog
,
3637 "KC: PTRACE_KILL %ld, 0, 0 (%s)\n", (long) pid
,
3638 save_errno
? safe_strerror (save_errno
) : "OK");
3642 /* Wait for an LWP to die. */
3645 kill_wait_one_lwp (pid_t pid
)
3649 /* We must make sure that there are no pending events (delayed
3650 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3651 program doesn't interfere with any following debugging session. */
3655 res
= my_waitpid (pid
, NULL
, __WALL
);
3656 if (res
!= (pid_t
) -1)
3658 if (debug_linux_nat
)
3659 fprintf_unfiltered (gdb_stdlog
,
3660 "KWC: wait %ld received unknown.\n",
3662 /* The Linux kernel sometimes fails to kill a thread
3663 completely after PTRACE_KILL; that goes from the stop
3664 point in do_fork out to the one in get_signal_to_deliver
3665 and waits again. So kill it again. */
3671 gdb_assert (res
== -1 && errno
== ECHILD
);
3674 /* Callback for iterate_over_lwps. */
3677 kill_callback (struct lwp_info
*lp
)
3679 kill_one_lwp (lp
->ptid
.lwp ());
3683 /* Callback for iterate_over_lwps. */
3686 kill_wait_callback (struct lwp_info
*lp
)
3688 kill_wait_one_lwp (lp
->ptid
.lwp ());
3692 /* Kill the fork children of any threads of inferior INF that are
3693 stopped at a fork event. */
3696 kill_unfollowed_fork_children (struct inferior
*inf
)
3698 for (thread_info
*thread
: inf
->non_exited_threads ())
3700 struct target_waitstatus
*ws
= &thread
->pending_follow
;
3702 if (ws
->kind
== TARGET_WAITKIND_FORKED
3703 || ws
->kind
== TARGET_WAITKIND_VFORKED
)
3705 ptid_t child_ptid
= ws
->value
.related_pid
;
3706 int child_pid
= child_ptid
.pid ();
3707 int child_lwp
= child_ptid
.lwp ();
3709 kill_one_lwp (child_lwp
);
3710 kill_wait_one_lwp (child_lwp
);
3712 /* Let the arch-specific native code know this process is
3714 linux_target
->low_forget_process (child_pid
);
3720 linux_nat_target::kill ()
3722 /* If we're stopped while forking and we haven't followed yet,
3723 kill the other task. We need to do this first because the
3724 parent will be sleeping if this is a vfork. */
3725 kill_unfollowed_fork_children (current_inferior ());
3727 if (forks_exist_p ())
3728 linux_fork_killall ();
3731 ptid_t ptid
= ptid_t (inferior_ptid
.pid ());
3733 /* Stop all threads before killing them, since ptrace requires
3734 that the thread is stopped to successfully PTRACE_KILL. */
3735 iterate_over_lwps (ptid
, stop_callback
);
3736 /* ... and wait until all of them have reported back that
3737 they're no longer running. */
3738 iterate_over_lwps (ptid
, stop_wait_callback
);
3740 /* Kill all LWP's ... */
3741 iterate_over_lwps (ptid
, kill_callback
);
3743 /* ... and wait until we've flushed all events. */
3744 iterate_over_lwps (ptid
, kill_wait_callback
);
3747 target_mourn_inferior (inferior_ptid
);
3751 linux_nat_target::mourn_inferior ()
3753 int pid
= inferior_ptid
.pid ();
3755 purge_lwp_list (pid
);
3757 if (! forks_exist_p ())
3758 /* Normal case, no other forks available. */
3759 inf_ptrace_target::mourn_inferior ();
3761 /* Multi-fork case. The current inferior_ptid has exited, but
3762 there are other viable forks to debug. Delete the exiting
3763 one and context-switch to the first available. */
3764 linux_fork_mourn_inferior ();
3766 /* Let the arch-specific native code know this process is gone. */
3767 linux_target
->low_forget_process (pid
);
3770 /* Convert a native/host siginfo object, into/from the siginfo in the
3771 layout of the inferiors' architecture. */
3774 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3776 /* If the low target didn't do anything, then just do a straight
3778 if (!linux_target
->low_siginfo_fixup (siginfo
, inf_siginfo
, direction
))
3781 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3783 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3787 static enum target_xfer_status
3788 linux_xfer_siginfo (enum target_object object
,
3789 const char *annex
, gdb_byte
*readbuf
,
3790 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3791 ULONGEST
*xfered_len
)
3795 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3797 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3798 gdb_assert (readbuf
|| writebuf
);
3800 pid
= inferior_ptid
.lwp ();
3802 pid
= inferior_ptid
.pid ();
3804 if (offset
> sizeof (siginfo
))
3805 return TARGET_XFER_E_IO
;
3808 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3810 return TARGET_XFER_E_IO
;
3812 /* When GDB is built as a 64-bit application, ptrace writes into
3813 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3814 inferior with a 64-bit GDB should look the same as debugging it
3815 with a 32-bit GDB, we need to convert it. GDB core always sees
3816 the converted layout, so any read/write will have to be done
3818 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3820 if (offset
+ len
> sizeof (siginfo
))
3821 len
= sizeof (siginfo
) - offset
;
3823 if (readbuf
!= NULL
)
3824 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3827 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3829 /* Convert back to ptrace layout before flushing it out. */
3830 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3833 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3835 return TARGET_XFER_E_IO
;
3839 return TARGET_XFER_OK
;
3842 static enum target_xfer_status
3843 linux_nat_xfer_osdata (enum target_object object
,
3844 const char *annex
, gdb_byte
*readbuf
,
3845 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3846 ULONGEST
*xfered_len
);
3848 static enum target_xfer_status
3849 linux_proc_xfer_partial (enum target_object object
,
3850 const char *annex
, gdb_byte
*readbuf
,
3851 const gdb_byte
*writebuf
,
3852 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
);
3854 enum target_xfer_status
3855 linux_nat_target::xfer_partial (enum target_object object
,
3856 const char *annex
, gdb_byte
*readbuf
,
3857 const gdb_byte
*writebuf
,
3858 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3860 enum target_xfer_status xfer
;
3862 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3863 return linux_xfer_siginfo (object
, annex
, readbuf
, writebuf
,
3864 offset
, len
, xfered_len
);
3866 /* The target is connected but no live inferior is selected. Pass
3867 this request down to a lower stratum (e.g., the executable
3869 if (object
== TARGET_OBJECT_MEMORY
&& inferior_ptid
== null_ptid
)
3870 return TARGET_XFER_EOF
;
3872 if (object
== TARGET_OBJECT_AUXV
)
3873 return memory_xfer_auxv (this, object
, annex
, readbuf
, writebuf
,
3874 offset
, len
, xfered_len
);
3876 if (object
== TARGET_OBJECT_OSDATA
)
3877 return linux_nat_xfer_osdata (object
, annex
, readbuf
, writebuf
,
3878 offset
, len
, xfered_len
);
3880 /* GDB calculates all addresses in the largest possible address
3882 The address width must be masked before its final use - either by
3883 linux_proc_xfer_partial or inf_ptrace_target::xfer_partial.
3885 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
3887 if (object
== TARGET_OBJECT_MEMORY
)
3889 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
3891 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
3892 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
3895 xfer
= linux_proc_xfer_partial (object
, annex
, readbuf
, writebuf
,
3896 offset
, len
, xfered_len
);
3897 if (xfer
!= TARGET_XFER_EOF
)
3900 return inf_ptrace_target::xfer_partial (object
, annex
, readbuf
, writebuf
,
3901 offset
, len
, xfered_len
);
3905 linux_nat_target::thread_alive (ptid_t ptid
)
3907 /* As long as a PTID is in lwp list, consider it alive. */
3908 return find_lwp_pid (ptid
) != NULL
;
3911 /* Implement the to_update_thread_list target method for this
3915 linux_nat_target::update_thread_list ()
3917 struct lwp_info
*lwp
;
3919 /* We add/delete threads from the list as clone/exit events are
3920 processed, so just try deleting exited threads still in the
3922 delete_exited_threads ();
3924 /* Update the processor core that each lwp/thread was last seen
3928 /* Avoid accessing /proc if the thread hasn't run since we last
3929 time we fetched the thread's core. Accessing /proc becomes
3930 noticeably expensive when we have thousands of LWPs. */
3931 if (lwp
->core
== -1)
3932 lwp
->core
= linux_common_core_of_thread (lwp
->ptid
);
3937 linux_nat_target::pid_to_str (ptid_t ptid
)
3940 && (ptid
.pid () != ptid
.lwp ()
3941 || num_lwps (ptid
.pid ()) > 1))
3942 return string_printf ("LWP %ld", ptid
.lwp ());
3944 return normal_pid_to_str (ptid
);
3948 linux_nat_target::thread_name (struct thread_info
*thr
)
3950 return linux_proc_tid_get_name (thr
->ptid
);
3953 /* Accepts an integer PID; Returns a string representing a file that
3954 can be opened to get the symbols for the child process. */
3957 linux_nat_target::pid_to_exec_file (int pid
)
3959 return linux_proc_pid_to_exec_file (pid
);
3962 /* Implement the to_xfer_partial target method using /proc/<pid>/mem.
3963 Because we can use a single read/write call, this can be much more
3964 efficient than banging away at PTRACE_PEEKTEXT. */
3966 static enum target_xfer_status
3967 linux_proc_xfer_partial (enum target_object object
,
3968 const char *annex
, gdb_byte
*readbuf
,
3969 const gdb_byte
*writebuf
,
3970 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
3976 if (object
!= TARGET_OBJECT_MEMORY
)
3977 return TARGET_XFER_EOF
;
3979 /* Don't bother for one word. */
3980 if (len
< 3 * sizeof (long))
3981 return TARGET_XFER_EOF
;
3983 /* We could keep this file open and cache it - possibly one per
3984 thread. That requires some juggling, but is even faster. */
3985 xsnprintf (filename
, sizeof filename
, "/proc/%ld/mem",
3986 inferior_ptid
.lwp ());
3987 fd
= gdb_open_cloexec (filename
, ((readbuf
? O_RDONLY
: O_WRONLY
)
3990 return TARGET_XFER_EOF
;
3992 /* Use pread64/pwrite64 if available, since they save a syscall and can
3993 handle 64-bit offsets even on 32-bit platforms (for instance, SPARC
3994 debugging a SPARC64 application). */
3996 ret
= (readbuf
? pread64 (fd
, readbuf
, len
, offset
)
3997 : pwrite64 (fd
, writebuf
, len
, offset
));
3999 ret
= lseek (fd
, offset
, SEEK_SET
);
4001 ret
= (readbuf
? read (fd
, readbuf
, len
)
4002 : write (fd
, writebuf
, len
));
4007 if (ret
== -1 || ret
== 0)
4008 return TARGET_XFER_EOF
;
4012 return TARGET_XFER_OK
;
4017 /* Parse LINE as a signal set and add its set bits to SIGS. */
4020 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4022 int len
= strlen (line
) - 1;
4026 if (line
[len
] != '\n')
4027 error (_("Could not parse signal set: %s"), line
);
4035 if (*p
>= '0' && *p
<= '9')
4037 else if (*p
>= 'a' && *p
<= 'f')
4038 digit
= *p
- 'a' + 10;
4040 error (_("Could not parse signal set: %s"), line
);
4045 sigaddset (sigs
, signum
+ 1);
4047 sigaddset (sigs
, signum
+ 2);
4049 sigaddset (sigs
, signum
+ 3);
4051 sigaddset (sigs
, signum
+ 4);
4057 /* Find process PID's pending signals from /proc/pid/status and set
4061 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4062 sigset_t
*blocked
, sigset_t
*ignored
)
4064 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4066 sigemptyset (pending
);
4067 sigemptyset (blocked
);
4068 sigemptyset (ignored
);
4069 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4070 gdb_file_up procfile
= gdb_fopen_cloexec (fname
, "r");
4071 if (procfile
== NULL
)
4072 error (_("Could not open %s"), fname
);
4074 while (fgets (buffer
, PATH_MAX
, procfile
.get ()) != NULL
)
4076 /* Normal queued signals are on the SigPnd line in the status
4077 file. However, 2.6 kernels also have a "shared" pending
4078 queue for delivering signals to a thread group, so check for
4081 Unfortunately some Red Hat kernels include the shared pending
4082 queue but not the ShdPnd status field. */
4084 if (startswith (buffer
, "SigPnd:\t"))
4085 add_line_to_sigset (buffer
+ 8, pending
);
4086 else if (startswith (buffer
, "ShdPnd:\t"))
4087 add_line_to_sigset (buffer
+ 8, pending
);
4088 else if (startswith (buffer
, "SigBlk:\t"))
4089 add_line_to_sigset (buffer
+ 8, blocked
);
4090 else if (startswith (buffer
, "SigIgn:\t"))
4091 add_line_to_sigset (buffer
+ 8, ignored
);
4095 static enum target_xfer_status
4096 linux_nat_xfer_osdata (enum target_object object
,
4097 const char *annex
, gdb_byte
*readbuf
,
4098 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4099 ULONGEST
*xfered_len
)
4101 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4103 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4104 if (*xfered_len
== 0)
4105 return TARGET_XFER_EOF
;
4107 return TARGET_XFER_OK
;
4110 std::vector
<static_tracepoint_marker
>
4111 linux_nat_target::static_tracepoint_markers_by_strid (const char *strid
)
4113 char s
[IPA_CMD_BUF_SIZE
];
4114 int pid
= inferior_ptid
.pid ();
4115 std::vector
<static_tracepoint_marker
> markers
;
4117 ptid_t ptid
= ptid_t (pid
, 0, 0);
4118 static_tracepoint_marker marker
;
4123 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4124 s
[sizeof ("qTfSTM")] = 0;
4126 agent_run_command (pid
, s
, strlen (s
) + 1);
4129 SCOPE_EXIT
{ target_continue_no_signal (ptid
); };
4135 parse_static_tracepoint_marker_definition (p
, &p
, &marker
);
4137 if (strid
== NULL
|| marker
.str_id
== strid
)
4138 markers
.push_back (std::move (marker
));
4140 while (*p
++ == ','); /* comma-separated list */
4142 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4143 s
[sizeof ("qTsSTM")] = 0;
4144 agent_run_command (pid
, s
, strlen (s
) + 1);
4151 /* target_is_async_p implementation. */
4154 linux_nat_target::is_async_p ()
4156 return linux_is_async_p ();
4159 /* target_can_async_p implementation. */
4162 linux_nat_target::can_async_p ()
4164 /* We're always async, unless the user explicitly prevented it with the
4165 "maint set target-async" command. */
4166 return target_async_permitted
;
4170 linux_nat_target::supports_non_stop ()
4175 /* to_always_non_stop_p implementation. */
4178 linux_nat_target::always_non_stop_p ()
4183 /* True if we want to support multi-process. To be removed when GDB
4184 supports multi-exec. */
4186 int linux_multi_process
= 1;
4189 linux_nat_target::supports_multi_process ()
4191 return linux_multi_process
;
4195 linux_nat_target::supports_disable_randomization ()
4197 #ifdef HAVE_PERSONALITY
4204 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4205 so we notice when any child changes state, and notify the
4206 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4207 above to wait for the arrival of a SIGCHLD. */
4210 sigchld_handler (int signo
)
4212 int old_errno
= errno
;
4214 if (debug_linux_nat
)
4215 ui_file_write_async_safe (gdb_stdlog
,
4216 "sigchld\n", sizeof ("sigchld\n") - 1);
4218 if (signo
== SIGCHLD
4219 && linux_nat_event_pipe
[0] != -1)
4220 async_file_mark (); /* Let the event loop know that there are
4221 events to handle. */
4226 /* Callback registered with the target events file descriptor. */
4229 handle_target_event (int error
, gdb_client_data client_data
)
4231 inferior_event_handler (INF_REG_EVENT
, NULL
);
4234 /* Create/destroy the target events pipe. Returns previous state. */
4237 linux_async_pipe (int enable
)
4239 int previous
= linux_is_async_p ();
4241 if (previous
!= enable
)
4245 /* Block child signals while we create/destroy the pipe, as
4246 their handler writes to it. */
4247 block_child_signals (&prev_mask
);
4251 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4252 internal_error (__FILE__
, __LINE__
,
4253 "creating event pipe failed.");
4255 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4256 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4260 close (linux_nat_event_pipe
[0]);
4261 close (linux_nat_event_pipe
[1]);
4262 linux_nat_event_pipe
[0] = -1;
4263 linux_nat_event_pipe
[1] = -1;
4266 restore_child_signals_mask (&prev_mask
);
4273 linux_nat_target::async_wait_fd ()
4275 return linux_nat_event_pipe
[0];
4278 /* target_async implementation. */
4281 linux_nat_target::async (int enable
)
4285 if (!linux_async_pipe (1))
4287 add_file_handler (linux_nat_event_pipe
[0],
4288 handle_target_event
, NULL
);
4289 /* There may be pending events to handle. Tell the event loop
4296 delete_file_handler (linux_nat_event_pipe
[0]);
4297 linux_async_pipe (0);
4302 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4306 linux_nat_stop_lwp (struct lwp_info
*lwp
)
4310 if (debug_linux_nat
)
4311 fprintf_unfiltered (gdb_stdlog
,
4312 "LNSL: running -> suspending %s\n",
4313 target_pid_to_str (lwp
->ptid
).c_str ());
4316 if (lwp
->last_resume_kind
== resume_stop
)
4318 if (debug_linux_nat
)
4319 fprintf_unfiltered (gdb_stdlog
,
4320 "linux-nat: already stopping LWP %ld at "
4326 stop_callback (lwp
);
4327 lwp
->last_resume_kind
= resume_stop
;
4331 /* Already known to be stopped; do nothing. */
4333 if (debug_linux_nat
)
4335 if (find_thread_ptid (linux_target
, lwp
->ptid
)->stop_requested
)
4336 fprintf_unfiltered (gdb_stdlog
,
4337 "LNSL: already stopped/stop_requested %s\n",
4338 target_pid_to_str (lwp
->ptid
).c_str ());
4340 fprintf_unfiltered (gdb_stdlog
,
4341 "LNSL: already stopped/no "
4342 "stop_requested yet %s\n",
4343 target_pid_to_str (lwp
->ptid
).c_str ());
4350 linux_nat_target::stop (ptid_t ptid
)
4352 iterate_over_lwps (ptid
, linux_nat_stop_lwp
);
4356 linux_nat_target::close ()
4358 /* Unregister from the event loop. */
4362 inf_ptrace_target::close ();
4365 /* When requests are passed down from the linux-nat layer to the
4366 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4367 used. The address space pointer is stored in the inferior object,
4368 but the common code that is passed such ptid can't tell whether
4369 lwpid is a "main" process id or not (it assumes so). We reverse
4370 look up the "main" process id from the lwp here. */
4372 struct address_space
*
4373 linux_nat_target::thread_address_space (ptid_t ptid
)
4375 struct lwp_info
*lwp
;
4376 struct inferior
*inf
;
4379 if (ptid
.lwp () == 0)
4381 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4383 lwp
= find_lwp_pid (ptid
);
4384 pid
= lwp
->ptid
.pid ();
4388 /* A (pid,lwpid,0) ptid. */
4392 inf
= find_inferior_pid (this, pid
);
4393 gdb_assert (inf
!= NULL
);
4397 /* Return the cached value of the processor core for thread PTID. */
4400 linux_nat_target::core_of_thread (ptid_t ptid
)
4402 struct lwp_info
*info
= find_lwp_pid (ptid
);
4409 /* Implementation of to_filesystem_is_local. */
4412 linux_nat_target::filesystem_is_local ()
4414 struct inferior
*inf
= current_inferior ();
4416 if (inf
->fake_pid_p
|| inf
->pid
== 0)
4419 return linux_ns_same (inf
->pid
, LINUX_NS_MNT
);
4422 /* Convert the INF argument passed to a to_fileio_* method
4423 to a process ID suitable for passing to its corresponding
4424 linux_mntns_* function. If INF is non-NULL then the
4425 caller is requesting the filesystem seen by INF. If INF
4426 is NULL then the caller is requesting the filesystem seen
4427 by the GDB. We fall back to GDB's filesystem in the case
4428 that INF is non-NULL but its PID is unknown. */
4431 linux_nat_fileio_pid_of (struct inferior
*inf
)
4433 if (inf
== NULL
|| inf
->fake_pid_p
|| inf
->pid
== 0)
4439 /* Implementation of to_fileio_open. */
4442 linux_nat_target::fileio_open (struct inferior
*inf
, const char *filename
,
4443 int flags
, int mode
, int warn_if_slow
,
4450 if (fileio_to_host_openflags (flags
, &nat_flags
) == -1
4451 || fileio_to_host_mode (mode
, &nat_mode
) == -1)
4453 *target_errno
= FILEIO_EINVAL
;
4457 fd
= linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf
),
4458 filename
, nat_flags
, nat_mode
);
4460 *target_errno
= host_to_fileio_error (errno
);
4465 /* Implementation of to_fileio_readlink. */
4467 gdb::optional
<std::string
>
4468 linux_nat_target::fileio_readlink (struct inferior
*inf
, const char *filename
,
4474 len
= linux_mntns_readlink (linux_nat_fileio_pid_of (inf
),
4475 filename
, buf
, sizeof (buf
));
4478 *target_errno
= host_to_fileio_error (errno
);
4482 return std::string (buf
, len
);
4485 /* Implementation of to_fileio_unlink. */
4488 linux_nat_target::fileio_unlink (struct inferior
*inf
, const char *filename
,
4493 ret
= linux_mntns_unlink (linux_nat_fileio_pid_of (inf
),
4496 *target_errno
= host_to_fileio_error (errno
);
4501 /* Implementation of the to_thread_events method. */
4504 linux_nat_target::thread_events (int enable
)
4506 report_thread_events
= enable
;
4509 linux_nat_target::linux_nat_target ()
4511 /* We don't change the stratum; this target will sit at
4512 process_stratum and thread_db will set at thread_stratum. This
4513 is a little strange, since this is a multi-threaded-capable
4514 target, but we want to be on the stack below thread_db, and we
4515 also want to be used for single-threaded processes. */
4518 /* See linux-nat.h. */
4521 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4530 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4533 memset (siginfo
, 0, sizeof (*siginfo
));
4539 /* See nat/linux-nat.h. */
4542 current_lwp_ptid (void)
4544 gdb_assert (inferior_ptid
.lwp_p ());
4545 return inferior_ptid
;
4549 _initialize_linux_nat (void)
4551 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4552 &debug_linux_nat
, _("\
4553 Set debugging of GNU/Linux lwp module."), _("\
4554 Show debugging of GNU/Linux lwp module."), _("\
4555 Enables printf debugging output."),
4557 show_debug_linux_nat
,
4558 &setdebuglist
, &showdebuglist
);
4560 add_setshow_boolean_cmd ("linux-namespaces", class_maintenance
,
4561 &debug_linux_namespaces
, _("\
4562 Set debugging of GNU/Linux namespaces module."), _("\
4563 Show debugging of GNU/Linux namespaces module."), _("\
4564 Enables printf debugging output."),
4567 &setdebuglist
, &showdebuglist
);
4569 /* Install a SIGCHLD handler. */
4570 sigchld_action
.sa_handler
= sigchld_handler
;
4571 sigemptyset (&sigchld_action
.sa_mask
);
4572 sigchld_action
.sa_flags
= SA_RESTART
;
4574 /* Make it the default. */
4575 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4577 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4578 gdb_sigmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4579 sigdelset (&suspend_mask
, SIGCHLD
);
4581 sigemptyset (&blocked_mask
);
4583 lwp_lwpid_htab_create ();
4587 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4588 the GNU/Linux Threads library and therefore doesn't really belong
4591 /* Return the set of signals used by the threads library in *SET. */
4594 lin_thread_get_thread_signals (sigset_t
*set
)
4598 /* NPTL reserves the first two RT signals, but does not provide any
4599 way for the debugger to query the signal numbers - fortunately
4600 they don't change. */
4601 sigaddset (set
, __SIGRTMIN
);
4602 sigaddset (set
, __SIGRTMIN
+ 1);