1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2019 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
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"
71 /* This comment documents high-level logic of this file.
73 Waiting for events in sync mode
74 ===============================
76 When waiting for an event in a specific thread, we just use waitpid,
77 passing the specific pid, and not passing WNOHANG.
79 When waiting for an event in all threads, waitpid is not quite good:
81 - If the thread group leader exits while other threads in the thread
82 group still exist, waitpid(TGID, ...) hangs. That waitpid won't
83 return an exit status until the other threads in the group are
86 - When a non-leader thread execs, that thread just vanishes without
87 reporting an exit (so we'd hang if we waited for it explicitly in
88 that case). The exec event is instead reported to the TGID pid.
90 The solution is to always use -1 and WNOHANG, together with
93 First, we use non-blocking waitpid to check for events. If nothing is
94 found, we use sigsuspend to wait for SIGCHLD. When SIGCHLD arrives,
95 it means something happened to a child process. As soon as we know
96 there's an event, we get back to calling nonblocking waitpid.
98 Note that SIGCHLD should be blocked between waitpid and sigsuspend
99 calls, so that we don't miss a signal. If SIGCHLD arrives in between,
100 when it's blocked, the signal becomes pending and sigsuspend
101 immediately notices it and returns.
103 Waiting for events in async mode (TARGET_WNOHANG)
104 =================================================
106 In async mode, GDB should always be ready to handle both user input
107 and target events, so neither blocking waitpid nor sigsuspend are
108 viable options. Instead, we should asynchronously notify the GDB main
109 event loop whenever there's an unprocessed event from the target. We
110 detect asynchronous target events by handling SIGCHLD signals. To
111 notify the event loop about target events, the self-pipe trick is used
112 --- a pipe is registered as waitable event source in the event loop,
113 the event loop select/poll's on the read end of this pipe (as well on
114 other event sources, e.g., stdin), and the SIGCHLD handler writes a
115 byte to this pipe. This is more portable than relying on
116 pselect/ppoll, since on kernels that lack those syscalls, libc
117 emulates them with select/poll+sigprocmask, and that is racy
118 (a.k.a. plain broken).
120 Obviously, if we fail to notify the event loop if there's a target
121 event, it's bad. OTOH, if we notify the event loop when there's no
122 event from the target, linux_nat_wait will detect that there's no real
123 event to report, and return event of type TARGET_WAITKIND_IGNORE.
124 This is mostly harmless, but it will waste time and is better avoided.
126 The main design point is that every time GDB is outside linux-nat.c,
127 we have a SIGCHLD handler installed that is called when something
128 happens to the target and notifies the GDB event loop. Whenever GDB
129 core decides to handle the event, and calls into linux-nat.c, we
130 process things as in sync mode, except that the we never block in
133 While processing an event, we may end up momentarily blocked in
134 waitpid calls. Those waitpid calls, while blocking, are guarantied to
135 return quickly. E.g., in all-stop mode, before reporting to the core
136 that an LWP hit a breakpoint, all LWPs are stopped by sending them
137 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
138 Note that this is different from blocking indefinitely waiting for the
139 next event --- here, we're already handling an event.
144 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
145 signal is not entirely significant; we just need for a signal to be delivered,
146 so that we can intercept it. SIGSTOP's advantage is that it can not be
147 blocked. A disadvantage is that it is not a real-time signal, so it can only
148 be queued once; we do not keep track of other sources of SIGSTOP.
150 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
151 use them, because they have special behavior when the signal is generated -
152 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
153 kills the entire thread group.
155 A delivered SIGSTOP would stop the entire thread group, not just the thread we
156 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
157 cancel it (by PTRACE_CONT without passing SIGSTOP).
159 We could use a real-time signal instead. This would solve those problems; we
160 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
161 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
162 generates it, and there are races with trying to find a signal that is not
168 The case of a thread group (process) with 3 or more threads, and a
169 thread other than the leader execs is worth detailing:
171 On an exec, the Linux kernel destroys all threads except the execing
172 one in the thread group, and resets the execing thread's tid to the
173 tgid. No exit notification is sent for the execing thread -- from the
174 ptracer's perspective, it appears as though the execing thread just
175 vanishes. Until we reap all other threads except the leader and the
176 execing thread, the leader will be zombie, and the execing thread will
177 be in `D (disc sleep)' state. As soon as all other threads are
178 reaped, the execing thread changes its tid to the tgid, and the
179 previous (zombie) leader vanishes, giving place to the "new"
183 #define O_LARGEFILE 0
186 struct linux_nat_target
*linux_target
;
188 /* Does the current host support PTRACE_GETREGSET? */
189 enum tribool have_ptrace_getregset
= TRIBOOL_UNKNOWN
;
191 static unsigned int debug_linux_nat
;
193 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
194 struct cmd_list_element
*c
, const char *value
)
196 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
200 struct simple_pid_list
204 struct simple_pid_list
*next
;
206 struct simple_pid_list
*stopped_pids
;
208 /* Whether target_thread_events is in effect. */
209 static int report_thread_events
;
211 /* Async mode support. */
213 /* The read/write ends of the pipe registered as waitable file in the
215 static int linux_nat_event_pipe
[2] = { -1, -1 };
217 /* True if we're currently in async mode. */
218 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
220 /* Flush the event pipe. */
223 async_file_flush (void)
230 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
232 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
235 /* Put something (anything, doesn't matter what, or how much) in event
236 pipe, so that the select/poll in the event-loop realizes we have
237 something to process. */
240 async_file_mark (void)
244 /* It doesn't really matter what the pipe contains, as long we end
245 up with something in it. Might as well flush the previous
251 ret
= write (linux_nat_event_pipe
[1], "+", 1);
253 while (ret
== -1 && errno
== EINTR
);
255 /* Ignore EAGAIN. If the pipe is full, the event loop will already
256 be awakened anyway. */
259 static int kill_lwp (int lwpid
, int signo
);
261 static int stop_callback (struct lwp_info
*lp
);
263 static void block_child_signals (sigset_t
*prev_mask
);
264 static void restore_child_signals_mask (sigset_t
*prev_mask
);
267 static struct lwp_info
*add_lwp (ptid_t ptid
);
268 static void purge_lwp_list (int pid
);
269 static void delete_lwp (ptid_t ptid
);
270 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
272 static int lwp_status_pending_p (struct lwp_info
*lp
);
274 static void save_stop_reason (struct lwp_info
*lp
);
279 /* See nat/linux-nat.h. */
282 ptid_of_lwp (struct lwp_info
*lwp
)
287 /* See nat/linux-nat.h. */
290 lwp_set_arch_private_info (struct lwp_info
*lwp
,
291 struct arch_lwp_info
*info
)
293 lwp
->arch_private
= info
;
296 /* See nat/linux-nat.h. */
298 struct arch_lwp_info
*
299 lwp_arch_private_info (struct lwp_info
*lwp
)
301 return lwp
->arch_private
;
304 /* See nat/linux-nat.h. */
307 lwp_is_stopped (struct lwp_info
*lwp
)
312 /* See nat/linux-nat.h. */
314 enum target_stop_reason
315 lwp_stop_reason (struct lwp_info
*lwp
)
317 return lwp
->stop_reason
;
320 /* See nat/linux-nat.h. */
323 lwp_is_stepping (struct lwp_info
*lwp
)
329 /* Trivial list manipulation functions to keep track of a list of
330 new stopped processes. */
332 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
334 struct simple_pid_list
*new_pid
= XNEW (struct simple_pid_list
);
337 new_pid
->status
= status
;
338 new_pid
->next
= *listp
;
343 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
345 struct simple_pid_list
**p
;
347 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
348 if ((*p
)->pid
== pid
)
350 struct simple_pid_list
*next
= (*p
)->next
;
352 *statusp
= (*p
)->status
;
360 /* Return the ptrace options that we want to try to enable. */
363 linux_nat_ptrace_options (int attached
)
368 options
|= PTRACE_O_EXITKILL
;
370 options
|= (PTRACE_O_TRACESYSGOOD
371 | PTRACE_O_TRACEVFORKDONE
372 | PTRACE_O_TRACEVFORK
374 | PTRACE_O_TRACEEXEC
);
379 /* Initialize ptrace and procfs warnings and check for supported
380 ptrace features given PID.
382 ATTACHED should be nonzero iff we attached to the inferior. */
385 linux_init_ptrace_procfs (pid_t pid
, int attached
)
387 int options
= linux_nat_ptrace_options (attached
);
389 linux_enable_event_reporting (pid
, options
);
390 linux_ptrace_init_warnings ();
391 linux_proc_init_warnings ();
394 linux_nat_target::~linux_nat_target ()
398 linux_nat_target::post_attach (int pid
)
400 linux_init_ptrace_procfs (pid
, 1);
404 linux_nat_target::post_startup_inferior (ptid_t ptid
)
406 linux_init_ptrace_procfs (ptid
.pid (), 0);
409 /* Return the number of known LWPs in the tgid given by PID. */
417 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
418 if (lp
->ptid
.pid () == pid
)
424 /* Deleter for lwp_info unique_ptr specialisation. */
428 void operator() (struct lwp_info
*lwp
) const
430 delete_lwp (lwp
->ptid
);
434 /* A unique_ptr specialisation for lwp_info. */
436 typedef std::unique_ptr
<struct lwp_info
, lwp_deleter
> lwp_info_up
;
438 /* Target hook for follow_fork. On entry inferior_ptid must be the
439 ptid of the followed inferior. At return, inferior_ptid will be
443 linux_nat_target::follow_fork (int follow_child
, int detach_fork
)
447 struct lwp_info
*child_lp
= NULL
;
449 ptid_t parent_ptid
, child_ptid
;
450 int parent_pid
, child_pid
;
452 has_vforked
= (inferior_thread ()->pending_follow
.kind
453 == TARGET_WAITKIND_VFORKED
);
454 parent_ptid
= inferior_ptid
;
455 child_ptid
= inferior_thread ()->pending_follow
.value
.related_pid
;
456 parent_pid
= parent_ptid
.lwp ();
457 child_pid
= child_ptid
.lwp ();
459 /* We're already attached to the parent, by default. */
460 child_lp
= add_lwp (child_ptid
);
461 child_lp
->stopped
= 1;
462 child_lp
->last_resume_kind
= resume_stop
;
464 /* Detach new forked process? */
467 int child_stop_signal
= 0;
468 bool detach_child
= true;
470 /* Move CHILD_LP into a unique_ptr and clear the source pointer
471 to prevent us doing anything stupid with it. */
472 lwp_info_up
child_lp_ptr (child_lp
);
475 linux_target
->low_prepare_to_resume (child_lp_ptr
.get ());
477 /* When debugging an inferior in an architecture that supports
478 hardware single stepping on a kernel without commit
479 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
480 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
481 set if the parent process had them set.
482 To work around this, single step the child process
483 once before detaching to clear the flags. */
485 /* Note that we consult the parent's architecture instead of
486 the child's because there's no inferior for the child at
488 if (!gdbarch_software_single_step_p (target_thread_architecture
493 linux_disable_event_reporting (child_pid
);
494 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
495 perror_with_name (_("Couldn't do single step"));
496 if (my_waitpid (child_pid
, &status
, 0) < 0)
497 perror_with_name (_("Couldn't wait vfork process"));
500 detach_child
= WIFSTOPPED (status
);
501 child_stop_signal
= WSTOPSIG (status
);
507 int signo
= child_stop_signal
;
510 && !signal_pass_state (gdb_signal_from_host (signo
)))
512 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
517 scoped_restore save_inferior_ptid
518 = make_scoped_restore (&inferior_ptid
);
519 inferior_ptid
= child_ptid
;
521 /* Let the thread_db layer learn about this new process. */
522 check_for_thread_db ();
527 struct lwp_info
*parent_lp
;
529 parent_lp
= find_lwp_pid (parent_ptid
);
530 gdb_assert (linux_supports_tracefork () >= 0);
532 if (linux_supports_tracevforkdone ())
535 fprintf_unfiltered (gdb_stdlog
,
536 "LCFF: waiting for VFORK_DONE on %d\n",
538 parent_lp
->stopped
= 1;
540 /* We'll handle the VFORK_DONE event like any other
541 event, in target_wait. */
545 /* We can't insert breakpoints until the child has
546 finished with the shared memory region. We need to
547 wait until that happens. Ideal would be to just
549 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
550 - waitpid (parent_pid, &status, __WALL);
551 However, most architectures can't handle a syscall
552 being traced on the way out if it wasn't traced on
555 We might also think to loop, continuing the child
556 until it exits or gets a SIGTRAP. One problem is
557 that the child might call ptrace with PTRACE_TRACEME.
559 There's no simple and reliable way to figure out when
560 the vforked child will be done with its copy of the
561 shared memory. We could step it out of the syscall,
562 two instructions, let it go, and then single-step the
563 parent once. When we have hardware single-step, this
564 would work; with software single-step it could still
565 be made to work but we'd have to be able to insert
566 single-step breakpoints in the child, and we'd have
567 to insert -just- the single-step breakpoint in the
568 parent. Very awkward.
570 In the end, the best we can do is to make sure it
571 runs for a little while. Hopefully it will be out of
572 range of any breakpoints we reinsert. Usually this
573 is only the single-step breakpoint at vfork's return
577 fprintf_unfiltered (gdb_stdlog
,
578 "LCFF: no VFORK_DONE "
579 "support, sleeping a bit\n");
583 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
584 and leave it pending. The next linux_nat_resume call
585 will notice a pending event, and bypasses actually
586 resuming the inferior. */
587 parent_lp
->status
= 0;
588 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
589 parent_lp
->stopped
= 1;
591 /* If we're in async mode, need to tell the event loop
592 there's something here to process. */
593 if (target_is_async_p ())
600 struct lwp_info
*child_lp
;
602 child_lp
= add_lwp (inferior_ptid
);
603 child_lp
->stopped
= 1;
604 child_lp
->last_resume_kind
= resume_stop
;
606 /* Let the thread_db layer learn about this new process. */
607 check_for_thread_db ();
615 linux_nat_target::insert_fork_catchpoint (int pid
)
617 return !linux_supports_tracefork ();
621 linux_nat_target::remove_fork_catchpoint (int pid
)
627 linux_nat_target::insert_vfork_catchpoint (int pid
)
629 return !linux_supports_tracefork ();
633 linux_nat_target::remove_vfork_catchpoint (int pid
)
639 linux_nat_target::insert_exec_catchpoint (int pid
)
641 return !linux_supports_tracefork ();
645 linux_nat_target::remove_exec_catchpoint (int pid
)
651 linux_nat_target::set_syscall_catchpoint (int pid
, bool needed
, int any_count
,
652 gdb::array_view
<const int> syscall_counts
)
654 if (!linux_supports_tracesysgood ())
657 /* On GNU/Linux, we ignore the arguments. It means that we only
658 enable the syscall catchpoints, but do not disable them.
660 Also, we do not use the `syscall_counts' information because we do not
661 filter system calls here. We let GDB do the logic for us. */
665 /* List of known LWPs, keyed by LWP PID. This speeds up the common
666 case of mapping a PID returned from the kernel to our corresponding
667 lwp_info data structure. */
668 static htab_t lwp_lwpid_htab
;
670 /* Calculate a hash from a lwp_info's LWP PID. */
673 lwp_info_hash (const void *ap
)
675 const struct lwp_info
*lp
= (struct lwp_info
*) ap
;
676 pid_t pid
= lp
->ptid
.lwp ();
678 return iterative_hash_object (pid
, 0);
681 /* Equality function for the lwp_info hash table. Compares the LWP's
685 lwp_lwpid_htab_eq (const void *a
, const void *b
)
687 const struct lwp_info
*entry
= (const struct lwp_info
*) a
;
688 const struct lwp_info
*element
= (const struct lwp_info
*) b
;
690 return entry
->ptid
.lwp () == element
->ptid
.lwp ();
693 /* Create the lwp_lwpid_htab hash table. */
696 lwp_lwpid_htab_create (void)
698 lwp_lwpid_htab
= htab_create (100, lwp_info_hash
, lwp_lwpid_htab_eq
, NULL
);
701 /* Add LP to the hash table. */
704 lwp_lwpid_htab_add_lwp (struct lwp_info
*lp
)
708 slot
= htab_find_slot (lwp_lwpid_htab
, lp
, INSERT
);
709 gdb_assert (slot
!= NULL
&& *slot
== NULL
);
713 /* Head of doubly-linked list of known LWPs. Sorted by reverse
714 creation order. This order is assumed in some cases. E.g.,
715 reaping status after killing alls lwps of a process: the leader LWP
716 must be reaped last. */
717 struct lwp_info
*lwp_list
;
719 /* Add LP to sorted-by-reverse-creation-order doubly-linked list. */
722 lwp_list_add (struct lwp_info
*lp
)
725 if (lwp_list
!= NULL
)
730 /* Remove LP from sorted-by-reverse-creation-order doubly-linked
734 lwp_list_remove (struct lwp_info
*lp
)
736 /* Remove from sorted-by-creation-order list. */
737 if (lp
->next
!= NULL
)
738 lp
->next
->prev
= lp
->prev
;
739 if (lp
->prev
!= NULL
)
740 lp
->prev
->next
= lp
->next
;
747 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
748 _initialize_linux_nat. */
749 static sigset_t suspend_mask
;
751 /* Signals to block to make that sigsuspend work. */
752 static sigset_t blocked_mask
;
754 /* SIGCHLD action. */
755 struct sigaction sigchld_action
;
757 /* Block child signals (SIGCHLD and linux threads signals), and store
758 the previous mask in PREV_MASK. */
761 block_child_signals (sigset_t
*prev_mask
)
763 /* Make sure SIGCHLD is blocked. */
764 if (!sigismember (&blocked_mask
, SIGCHLD
))
765 sigaddset (&blocked_mask
, SIGCHLD
);
767 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
770 /* Restore child signals mask, previously returned by
771 block_child_signals. */
774 restore_child_signals_mask (sigset_t
*prev_mask
)
776 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
779 /* Mask of signals to pass directly to the inferior. */
780 static sigset_t pass_mask
;
782 /* Update signals to pass to the inferior. */
784 linux_nat_target::pass_signals
785 (gdb::array_view
<const unsigned char> pass_signals
)
789 sigemptyset (&pass_mask
);
791 for (signo
= 1; signo
< NSIG
; signo
++)
793 int target_signo
= gdb_signal_from_host (signo
);
794 if (target_signo
< pass_signals
.size () && pass_signals
[target_signo
])
795 sigaddset (&pass_mask
, signo
);
801 /* Prototypes for local functions. */
802 static int stop_wait_callback (struct lwp_info
*lp
);
803 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, const ptid_t wait_ptid
);
804 static int check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
);
808 /* Destroy and free LP. */
811 lwp_free (struct lwp_info
*lp
)
813 /* Let the arch specific bits release arch_lwp_info. */
814 linux_target
->low_delete_thread (lp
->arch_private
);
819 /* Traversal function for purge_lwp_list. */
822 lwp_lwpid_htab_remove_pid (void **slot
, void *info
)
824 struct lwp_info
*lp
= (struct lwp_info
*) *slot
;
825 int pid
= *(int *) info
;
827 if (lp
->ptid
.pid () == pid
)
829 htab_clear_slot (lwp_lwpid_htab
, slot
);
830 lwp_list_remove (lp
);
837 /* Remove all LWPs belong to PID from the lwp list. */
840 purge_lwp_list (int pid
)
842 htab_traverse_noresize (lwp_lwpid_htab
, lwp_lwpid_htab_remove_pid
, &pid
);
845 /* Add the LWP specified by PTID to the list. PTID is the first LWP
846 in the process. Return a pointer to the structure describing the
849 This differs from add_lwp in that we don't let the arch specific
850 bits know about this new thread. Current clients of this callback
851 take the opportunity to install watchpoints in the new thread, and
852 we shouldn't do that for the first thread. If we're spawning a
853 child ("run"), the thread executes the shell wrapper first, and we
854 shouldn't touch it until it execs the program we want to debug.
855 For "attach", it'd be okay to call the callback, but it's not
856 necessary, because watchpoints can't yet have been inserted into
859 static struct lwp_info
*
860 add_initial_lwp (ptid_t ptid
)
864 gdb_assert (ptid
.lwp_p ());
866 lp
= XNEW (struct lwp_info
);
868 memset (lp
, 0, sizeof (struct lwp_info
));
870 lp
->last_resume_kind
= resume_continue
;
871 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
876 /* Add to sorted-by-reverse-creation-order list. */
879 /* Add to keyed-by-pid htab. */
880 lwp_lwpid_htab_add_lwp (lp
);
885 /* Add the LWP specified by PID to the list. Return a pointer to the
886 structure describing the new LWP. The LWP should already be
889 static struct lwp_info
*
890 add_lwp (ptid_t ptid
)
894 lp
= add_initial_lwp (ptid
);
896 /* Let the arch specific bits know about this new thread. Current
897 clients of this callback take the opportunity to install
898 watchpoints in the new thread. We don't do this for the first
899 thread though. See add_initial_lwp. */
900 linux_target
->low_new_thread (lp
);
905 /* Remove the LWP specified by PID from the list. */
908 delete_lwp (ptid_t ptid
)
912 struct lwp_info dummy
;
915 slot
= htab_find_slot (lwp_lwpid_htab
, &dummy
, NO_INSERT
);
919 lp
= *(struct lwp_info
**) slot
;
920 gdb_assert (lp
!= NULL
);
922 htab_clear_slot (lwp_lwpid_htab
, slot
);
924 /* Remove from sorted-by-creation-order list. */
925 lwp_list_remove (lp
);
931 /* Return a pointer to the structure describing the LWP corresponding
932 to PID. If no corresponding LWP could be found, return NULL. */
934 static struct lwp_info
*
935 find_lwp_pid (ptid_t ptid
)
939 struct lwp_info dummy
;
946 dummy
.ptid
= ptid_t (0, lwp
, 0);
947 lp
= (struct lwp_info
*) htab_find (lwp_lwpid_htab
, &dummy
);
951 /* See nat/linux-nat.h. */
954 iterate_over_lwps (ptid_t filter
,
955 gdb::function_view
<iterate_over_lwps_ftype
> callback
)
957 struct lwp_info
*lp
, *lpnext
;
959 for (lp
= lwp_list
; lp
; lp
= lpnext
)
963 if (lp
->ptid
.matches (filter
))
965 if (callback (lp
) != 0)
973 /* Update our internal state when changing from one checkpoint to
974 another indicated by NEW_PTID. We can only switch single-threaded
975 applications, so we only create one new LWP, and the previous list
979 linux_nat_switch_fork (ptid_t new_ptid
)
983 purge_lwp_list (inferior_ptid
.pid ());
985 lp
= add_lwp (new_ptid
);
988 /* This changes the thread's ptid while preserving the gdb thread
989 num. Also changes the inferior pid, while preserving the
991 thread_change_ptid (inferior_ptid
, new_ptid
);
993 /* We've just told GDB core that the thread changed target id, but,
994 in fact, it really is a different thread, with different register
996 registers_changed ();
999 /* Handle the exit of a single thread LP. */
1002 exit_lwp (struct lwp_info
*lp
)
1004 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1008 if (print_thread_events
)
1009 printf_unfiltered (_("[%s exited]\n"),
1010 target_pid_to_str (lp
->ptid
).c_str ());
1015 delete_lwp (lp
->ptid
);
1018 /* Wait for the LWP specified by LP, which we have just attached to.
1019 Returns a wait status for that LWP, to cache. */
1022 linux_nat_post_attach_wait (ptid_t ptid
, int *signalled
)
1024 pid_t new_pid
, pid
= ptid
.lwp ();
1027 if (linux_proc_pid_is_stopped (pid
))
1029 if (debug_linux_nat
)
1030 fprintf_unfiltered (gdb_stdlog
,
1031 "LNPAW: Attaching to a stopped process\n");
1033 /* The process is definitely stopped. It is in a job control
1034 stop, unless the kernel predates the TASK_STOPPED /
1035 TASK_TRACED distinction, in which case it might be in a
1036 ptrace stop. Make sure it is in a ptrace stop; from there we
1037 can kill it, signal it, et cetera.
1039 First make sure there is a pending SIGSTOP. Since we are
1040 already attached, the process can not transition from stopped
1041 to running without a PTRACE_CONT; so we know this signal will
1042 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1043 probably already in the queue (unless this kernel is old
1044 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1045 is not an RT signal, it can only be queued once. */
1046 kill_lwp (pid
, SIGSTOP
);
1048 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1049 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1050 ptrace (PTRACE_CONT
, pid
, 0, 0);
1053 /* Make sure the initial process is stopped. The user-level threads
1054 layer might want to poke around in the inferior, and that won't
1055 work if things haven't stabilized yet. */
1056 new_pid
= my_waitpid (pid
, &status
, __WALL
);
1057 gdb_assert (pid
== new_pid
);
1059 if (!WIFSTOPPED (status
))
1061 /* The pid we tried to attach has apparently just exited. */
1062 if (debug_linux_nat
)
1063 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1064 pid
, status_to_str (status
));
1068 if (WSTOPSIG (status
) != SIGSTOP
)
1071 if (debug_linux_nat
)
1072 fprintf_unfiltered (gdb_stdlog
,
1073 "LNPAW: Received %s after attaching\n",
1074 status_to_str (status
));
1081 linux_nat_target::create_inferior (const char *exec_file
,
1082 const std::string
&allargs
,
1083 char **env
, int from_tty
)
1085 maybe_disable_address_space_randomization restore_personality
1086 (disable_randomization
);
1088 /* The fork_child mechanism is synchronous and calls target_wait, so
1089 we have to mask the async mode. */
1091 /* Make sure we report all signals during startup. */
1094 inf_ptrace_target::create_inferior (exec_file
, allargs
, env
, from_tty
);
1097 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1098 already attached. Returns true if a new LWP is found, false
1102 attach_proc_task_lwp_callback (ptid_t ptid
)
1104 struct lwp_info
*lp
;
1106 /* Ignore LWPs we're already attached to. */
1107 lp
= find_lwp_pid (ptid
);
1110 int lwpid
= ptid
.lwp ();
1112 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1116 /* Be quiet if we simply raced with the thread exiting.
1117 EPERM is returned if the thread's task still exists, and
1118 is marked as exited or zombie, as well as other
1119 conditions, so in that case, confirm the status in
1120 /proc/PID/status. */
1122 || (err
== EPERM
&& linux_proc_pid_is_gone (lwpid
)))
1124 if (debug_linux_nat
)
1126 fprintf_unfiltered (gdb_stdlog
,
1127 "Cannot attach to lwp %d: "
1128 "thread is gone (%d: %s)\n",
1129 lwpid
, err
, safe_strerror (err
));
1135 = linux_ptrace_attach_fail_reason_lwp (ptid
, err
);
1137 warning (_("Cannot attach to lwp %d: %s"),
1138 lwpid
, reason
.c_str ());
1143 if (debug_linux_nat
)
1144 fprintf_unfiltered (gdb_stdlog
,
1145 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1146 target_pid_to_str (ptid
).c_str ());
1148 lp
= add_lwp (ptid
);
1150 /* The next time we wait for this LWP we'll see a SIGSTOP as
1151 PTRACE_ATTACH brings it to a halt. */
1154 /* We need to wait for a stop before being able to make the
1155 next ptrace call on this LWP. */
1156 lp
->must_set_ptrace_flags
= 1;
1158 /* So that wait collects the SIGSTOP. */
1161 /* Also add the LWP to gdb's thread list, in case a
1162 matching libthread_db is not found (or the process uses
1164 add_thread (lp
->ptid
);
1165 set_running (lp
->ptid
, 1);
1166 set_executing (lp
->ptid
, 1);
1175 linux_nat_target::attach (const char *args
, int from_tty
)
1177 struct lwp_info
*lp
;
1181 /* Make sure we report all signals during attach. */
1186 inf_ptrace_target::attach (args
, from_tty
);
1188 catch (const gdb_exception_error
&ex
)
1190 int saved_errno
= errno
;
1191 pid_t pid
= parse_pid_to_attach (args
);
1192 std::string reason
= linux_ptrace_attach_fail_reason (pid
, saved_errno
);
1194 if (!reason
.empty ())
1195 throw_error (ex
.error
, "warning: %s\n%s", reason
.c_str (),
1198 throw_error (ex
.error
, "%s", ex
.what ());
1201 /* The ptrace base target adds the main thread with (pid,0,0)
1202 format. Decorate it with lwp info. */
1203 ptid
= ptid_t (inferior_ptid
.pid (),
1204 inferior_ptid
.pid (),
1206 thread_change_ptid (inferior_ptid
, ptid
);
1208 /* Add the initial process as the first LWP to the list. */
1209 lp
= add_initial_lwp (ptid
);
1211 status
= linux_nat_post_attach_wait (lp
->ptid
, &lp
->signalled
);
1212 if (!WIFSTOPPED (status
))
1214 if (WIFEXITED (status
))
1216 int exit_code
= WEXITSTATUS (status
);
1218 target_terminal::ours ();
1219 target_mourn_inferior (inferior_ptid
);
1221 error (_("Unable to attach: program exited normally."));
1223 error (_("Unable to attach: program exited with code %d."),
1226 else if (WIFSIGNALED (status
))
1228 enum gdb_signal signo
;
1230 target_terminal::ours ();
1231 target_mourn_inferior (inferior_ptid
);
1233 signo
= gdb_signal_from_host (WTERMSIG (status
));
1234 error (_("Unable to attach: program terminated with signal "
1236 gdb_signal_to_name (signo
),
1237 gdb_signal_to_string (signo
));
1240 internal_error (__FILE__
, __LINE__
,
1241 _("unexpected status %d for PID %ld"),
1242 status
, (long) ptid
.lwp ());
1247 /* Save the wait status to report later. */
1249 if (debug_linux_nat
)
1250 fprintf_unfiltered (gdb_stdlog
,
1251 "LNA: waitpid %ld, saving status %s\n",
1252 (long) lp
->ptid
.pid (), status_to_str (status
));
1254 lp
->status
= status
;
1256 /* We must attach to every LWP. If /proc is mounted, use that to
1257 find them now. The inferior may be using raw clone instead of
1258 using pthreads. But even if it is using pthreads, thread_db
1259 walks structures in the inferior's address space to find the list
1260 of threads/LWPs, and those structures may well be corrupted.
1261 Note that once thread_db is loaded, we'll still use it to list
1262 threads and associate pthread info with each LWP. */
1263 linux_proc_attach_tgid_threads (lp
->ptid
.pid (),
1264 attach_proc_task_lwp_callback
);
1266 if (target_can_async_p ())
1270 /* Get pending signal of THREAD as a host signal number, for detaching
1271 purposes. This is the signal the thread last stopped for, which we
1272 need to deliver to the thread when detaching, otherwise, it'd be
1276 get_detach_signal (struct lwp_info
*lp
)
1278 enum gdb_signal signo
= GDB_SIGNAL_0
;
1280 /* If we paused threads momentarily, we may have stored pending
1281 events in lp->status or lp->waitstatus (see stop_wait_callback),
1282 and GDB core hasn't seen any signal for those threads.
1283 Otherwise, the last signal reported to the core is found in the
1284 thread object's stop_signal.
1286 There's a corner case that isn't handled here at present. Only
1287 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1288 stop_signal make sense as a real signal to pass to the inferior.
1289 Some catchpoint related events, like
1290 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1291 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1292 those traps are debug API (ptrace in our case) related and
1293 induced; the inferior wouldn't see them if it wasn't being
1294 traced. Hence, we should never pass them to the inferior, even
1295 when set to pass state. Since this corner case isn't handled by
1296 infrun.c when proceeding with a signal, for consistency, neither
1297 do we handle it here (or elsewhere in the file we check for
1298 signal pass state). Normally SIGTRAP isn't set to pass state, so
1299 this is really a corner case. */
1301 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1302 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1303 else if (lp
->status
)
1304 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1307 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1309 if (target_is_non_stop_p () && !tp
->executing
)
1311 if (tp
->suspend
.waitstatus_pending_p
)
1312 signo
= tp
->suspend
.waitstatus
.value
.sig
;
1314 signo
= tp
->suspend
.stop_signal
;
1316 else if (!target_is_non_stop_p ())
1318 struct target_waitstatus last
;
1321 get_last_target_status (&last_ptid
, &last
);
1323 if (lp
->ptid
.lwp () == last_ptid
.lwp ())
1324 signo
= tp
->suspend
.stop_signal
;
1328 if (signo
== GDB_SIGNAL_0
)
1330 if (debug_linux_nat
)
1331 fprintf_unfiltered (gdb_stdlog
,
1332 "GPT: lwp %s has no pending signal\n",
1333 target_pid_to_str (lp
->ptid
).c_str ());
1335 else if (!signal_pass_state (signo
))
1337 if (debug_linux_nat
)
1338 fprintf_unfiltered (gdb_stdlog
,
1339 "GPT: lwp %s had signal %s, "
1340 "but it is in no pass state\n",
1341 target_pid_to_str (lp
->ptid
).c_str (),
1342 gdb_signal_to_string (signo
));
1346 if (debug_linux_nat
)
1347 fprintf_unfiltered (gdb_stdlog
,
1348 "GPT: lwp %s has pending signal %s\n",
1349 target_pid_to_str (lp
->ptid
).c_str (),
1350 gdb_signal_to_string (signo
));
1352 return gdb_signal_to_host (signo
);
1358 /* Detach from LP. If SIGNO_P is non-NULL, then it points to the
1359 signal number that should be passed to the LWP when detaching.
1360 Otherwise pass any pending signal the LWP may have, if any. */
1363 detach_one_lwp (struct lwp_info
*lp
, int *signo_p
)
1365 int lwpid
= lp
->ptid
.lwp ();
1368 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1370 if (debug_linux_nat
&& lp
->status
)
1371 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1372 strsignal (WSTOPSIG (lp
->status
)),
1373 target_pid_to_str (lp
->ptid
).c_str ());
1375 /* If there is a pending SIGSTOP, get rid of it. */
1378 if (debug_linux_nat
)
1379 fprintf_unfiltered (gdb_stdlog
,
1380 "DC: Sending SIGCONT to %s\n",
1381 target_pid_to_str (lp
->ptid
).c_str ());
1383 kill_lwp (lwpid
, SIGCONT
);
1387 if (signo_p
== NULL
)
1389 /* Pass on any pending signal for this LWP. */
1390 signo
= get_detach_signal (lp
);
1395 /* Preparing to resume may try to write registers, and fail if the
1396 lwp is zombie. If that happens, ignore the error. We'll handle
1397 it below, when detach fails with ESRCH. */
1400 linux_target
->low_prepare_to_resume (lp
);
1402 catch (const gdb_exception_error
&ex
)
1404 if (!check_ptrace_stopped_lwp_gone (lp
))
1408 if (ptrace (PTRACE_DETACH
, lwpid
, 0, signo
) < 0)
1410 int save_errno
= errno
;
1412 /* We know the thread exists, so ESRCH must mean the lwp is
1413 zombie. This can happen if one of the already-detached
1414 threads exits the whole thread group. In that case we're
1415 still attached, and must reap the lwp. */
1416 if (save_errno
== ESRCH
)
1420 ret
= my_waitpid (lwpid
, &status
, __WALL
);
1423 warning (_("Couldn't reap LWP %d while detaching: %s"),
1424 lwpid
, strerror (errno
));
1426 else if (!WIFEXITED (status
) && !WIFSIGNALED (status
))
1428 warning (_("Reaping LWP %d while detaching "
1429 "returned unexpected status 0x%x"),
1435 error (_("Can't detach %s: %s"),
1436 target_pid_to_str (lp
->ptid
).c_str (),
1437 safe_strerror (save_errno
));
1440 else if (debug_linux_nat
)
1442 fprintf_unfiltered (gdb_stdlog
,
1443 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1444 target_pid_to_str (lp
->ptid
).c_str (),
1448 delete_lwp (lp
->ptid
);
1452 detach_callback (struct lwp_info
*lp
)
1454 /* We don't actually detach from the thread group leader just yet.
1455 If the thread group exits, we must reap the zombie clone lwps
1456 before we're able to reap the leader. */
1457 if (lp
->ptid
.lwp () != lp
->ptid
.pid ())
1458 detach_one_lwp (lp
, NULL
);
1463 linux_nat_target::detach (inferior
*inf
, int from_tty
)
1465 struct lwp_info
*main_lwp
;
1468 /* Don't unregister from the event loop, as there may be other
1469 inferiors running. */
1471 /* Stop all threads before detaching. ptrace requires that the
1472 thread is stopped to sucessfully detach. */
1473 iterate_over_lwps (ptid_t (pid
), stop_callback
);
1474 /* ... and wait until all of them have reported back that
1475 they're no longer running. */
1476 iterate_over_lwps (ptid_t (pid
), stop_wait_callback
);
1478 iterate_over_lwps (ptid_t (pid
), detach_callback
);
1480 /* Only the initial process should be left right now. */
1481 gdb_assert (num_lwps (pid
) == 1);
1483 main_lwp
= find_lwp_pid (ptid_t (pid
));
1485 if (forks_exist_p ())
1487 /* Multi-fork case. The current inferior_ptid is being detached
1488 from, but there are other viable forks to debug. Detach from
1489 the current fork, and context-switch to the first
1491 linux_fork_detach (from_tty
);
1495 target_announce_detach (from_tty
);
1497 /* Pass on any pending signal for the last LWP. */
1498 int signo
= get_detach_signal (main_lwp
);
1500 detach_one_lwp (main_lwp
, &signo
);
1502 detach_success (inf
);
1506 /* Resume execution of the inferior process. If STEP is nonzero,
1507 single-step it. If SIGNAL is nonzero, give it that signal. */
1510 linux_resume_one_lwp_throw (struct lwp_info
*lp
, int step
,
1511 enum gdb_signal signo
)
1515 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1516 We only presently need that if the LWP is stepped though (to
1517 handle the case of stepping a breakpoint instruction). */
1520 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
1522 lp
->stop_pc
= regcache_read_pc (regcache
);
1527 linux_target
->low_prepare_to_resume (lp
);
1528 linux_target
->low_resume (lp
->ptid
, step
, signo
);
1530 /* Successfully resumed. Clear state that no longer makes sense,
1531 and mark the LWP as running. Must not do this before resuming
1532 otherwise if that fails other code will be confused. E.g., we'd
1533 later try to stop the LWP and hang forever waiting for a stop
1534 status. Note that we must not throw after this is cleared,
1535 otherwise handle_zombie_lwp_error would get confused. */
1538 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1539 registers_changed_ptid (lp
->ptid
);
1542 /* Called when we try to resume a stopped LWP and that errors out. If
1543 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1544 or about to become), discard the error, clear any pending status
1545 the LWP may have, and return true (we'll collect the exit status
1546 soon enough). Otherwise, return false. */
1549 check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
)
1551 /* If we get an error after resuming the LWP successfully, we'd
1552 confuse !T state for the LWP being gone. */
1553 gdb_assert (lp
->stopped
);
1555 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1556 because even if ptrace failed with ESRCH, the tracee may be "not
1557 yet fully dead", but already refusing ptrace requests. In that
1558 case the tracee has 'R (Running)' state for a little bit
1559 (observed in Linux 3.18). See also the note on ESRCH in the
1560 ptrace(2) man page. Instead, check whether the LWP has any state
1561 other than ptrace-stopped. */
1563 /* Don't assume anything if /proc/PID/status can't be read. */
1564 if (linux_proc_pid_is_trace_stopped_nowarn (lp
->ptid
.lwp ()) == 0)
1566 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1568 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
1574 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1575 disappears while we try to resume it. */
1578 linux_resume_one_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1582 linux_resume_one_lwp_throw (lp
, step
, signo
);
1584 catch (const gdb_exception_error
&ex
)
1586 if (!check_ptrace_stopped_lwp_gone (lp
))
1594 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1598 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
1600 if (inf
->vfork_child
!= NULL
)
1602 if (debug_linux_nat
)
1603 fprintf_unfiltered (gdb_stdlog
,
1604 "RC: Not resuming %s (vfork parent)\n",
1605 target_pid_to_str (lp
->ptid
).c_str ());
1607 else if (!lwp_status_pending_p (lp
))
1609 if (debug_linux_nat
)
1610 fprintf_unfiltered (gdb_stdlog
,
1611 "RC: Resuming sibling %s, %s, %s\n",
1612 target_pid_to_str (lp
->ptid
).c_str (),
1613 (signo
!= GDB_SIGNAL_0
1614 ? strsignal (gdb_signal_to_host (signo
))
1616 step
? "step" : "resume");
1618 linux_resume_one_lwp (lp
, step
, signo
);
1622 if (debug_linux_nat
)
1623 fprintf_unfiltered (gdb_stdlog
,
1624 "RC: Not resuming sibling %s (has pending)\n",
1625 target_pid_to_str (lp
->ptid
).c_str ());
1630 if (debug_linux_nat
)
1631 fprintf_unfiltered (gdb_stdlog
,
1632 "RC: Not resuming sibling %s (not stopped)\n",
1633 target_pid_to_str (lp
->ptid
).c_str ());
1637 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1638 Resume LWP with the last stop signal, if it is in pass state. */
1641 linux_nat_resume_callback (struct lwp_info
*lp
, struct lwp_info
*except
)
1643 enum gdb_signal signo
= GDB_SIGNAL_0
;
1650 struct thread_info
*thread
;
1652 thread
= find_thread_ptid (lp
->ptid
);
1655 signo
= thread
->suspend
.stop_signal
;
1656 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1660 resume_lwp (lp
, 0, signo
);
1665 resume_clear_callback (struct lwp_info
*lp
)
1668 lp
->last_resume_kind
= resume_stop
;
1673 resume_set_callback (struct lwp_info
*lp
)
1676 lp
->last_resume_kind
= resume_continue
;
1681 linux_nat_target::resume (ptid_t ptid
, int step
, enum gdb_signal signo
)
1683 struct lwp_info
*lp
;
1686 if (debug_linux_nat
)
1687 fprintf_unfiltered (gdb_stdlog
,
1688 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1689 step
? "step" : "resume",
1690 target_pid_to_str (ptid
).c_str (),
1691 (signo
!= GDB_SIGNAL_0
1692 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1693 target_pid_to_str (inferior_ptid
).c_str ());
1695 /* A specific PTID means `step only this process id'. */
1696 resume_many
= (minus_one_ptid
== ptid
1699 /* Mark the lwps we're resuming as resumed. */
1700 iterate_over_lwps (ptid
, resume_set_callback
);
1702 /* See if it's the current inferior that should be handled
1705 lp
= find_lwp_pid (inferior_ptid
);
1707 lp
= find_lwp_pid (ptid
);
1708 gdb_assert (lp
!= NULL
);
1710 /* Remember if we're stepping. */
1711 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1713 /* If we have a pending wait status for this thread, there is no
1714 point in resuming the process. But first make sure that
1715 linux_nat_wait won't preemptively handle the event - we
1716 should never take this short-circuit if we are going to
1717 leave LP running, since we have skipped resuming all the
1718 other threads. This bit of code needs to be synchronized
1719 with linux_nat_wait. */
1721 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1724 && WSTOPSIG (lp
->status
)
1725 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1727 if (debug_linux_nat
)
1728 fprintf_unfiltered (gdb_stdlog
,
1729 "LLR: Not short circuiting for ignored "
1730 "status 0x%x\n", lp
->status
);
1732 /* FIXME: What should we do if we are supposed to continue
1733 this thread with a signal? */
1734 gdb_assert (signo
== GDB_SIGNAL_0
);
1735 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1740 if (lwp_status_pending_p (lp
))
1742 /* FIXME: What should we do if we are supposed to continue
1743 this thread with a signal? */
1744 gdb_assert (signo
== GDB_SIGNAL_0
);
1746 if (debug_linux_nat
)
1747 fprintf_unfiltered (gdb_stdlog
,
1748 "LLR: Short circuiting for status 0x%x\n",
1751 if (target_can_async_p ())
1754 /* Tell the event loop we have something to process. */
1761 iterate_over_lwps (ptid
, [=] (struct lwp_info
*info
)
1763 return linux_nat_resume_callback (info
, lp
);
1766 if (debug_linux_nat
)
1767 fprintf_unfiltered (gdb_stdlog
,
1768 "LLR: %s %s, %s (resume event thread)\n",
1769 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1770 target_pid_to_str (lp
->ptid
).c_str (),
1771 (signo
!= GDB_SIGNAL_0
1772 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1774 linux_resume_one_lwp (lp
, step
, signo
);
1776 if (target_can_async_p ())
1780 /* Send a signal to an LWP. */
1783 kill_lwp (int lwpid
, int signo
)
1788 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1789 if (errno
== ENOSYS
)
1791 /* If tkill fails, then we are not using nptl threads, a
1792 configuration we no longer support. */
1793 perror_with_name (("tkill"));
1798 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1799 event, check if the core is interested in it: if not, ignore the
1800 event, and keep waiting; otherwise, we need to toggle the LWP's
1801 syscall entry/exit status, since the ptrace event itself doesn't
1802 indicate it, and report the trap to higher layers. */
1805 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1807 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1808 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1809 thread_info
*thread
= find_thread_ptid (lp
->ptid
);
1810 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, thread
);
1814 /* If we're stopping threads, there's a SIGSTOP pending, which
1815 makes it so that the LWP reports an immediate syscall return,
1816 followed by the SIGSTOP. Skip seeing that "return" using
1817 PTRACE_CONT directly, and let stop_wait_callback collect the
1818 SIGSTOP. Later when the thread is resumed, a new syscall
1819 entry event. If we didn't do this (and returned 0), we'd
1820 leave a syscall entry pending, and our caller, by using
1821 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1822 itself. Later, when the user re-resumes this LWP, we'd see
1823 another syscall entry event and we'd mistake it for a return.
1825 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1826 (leaving immediately with LWP->signalled set, without issuing
1827 a PTRACE_CONT), it would still be problematic to leave this
1828 syscall enter pending, as later when the thread is resumed,
1829 it would then see the same syscall exit mentioned above,
1830 followed by the delayed SIGSTOP, while the syscall didn't
1831 actually get to execute. It seems it would be even more
1832 confusing to the user. */
1834 if (debug_linux_nat
)
1835 fprintf_unfiltered (gdb_stdlog
,
1836 "LHST: ignoring syscall %d "
1837 "for LWP %ld (stopping threads), "
1838 "resuming with PTRACE_CONT for SIGSTOP\n",
1842 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1843 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
1848 /* Always update the entry/return state, even if this particular
1849 syscall isn't interesting to the core now. In async mode,
1850 the user could install a new catchpoint for this syscall
1851 between syscall enter/return, and we'll need to know to
1852 report a syscall return if that happens. */
1853 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1854 ? TARGET_WAITKIND_SYSCALL_RETURN
1855 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1857 if (catch_syscall_enabled ())
1859 if (catching_syscall_number (syscall_number
))
1861 /* Alright, an event to report. */
1862 ourstatus
->kind
= lp
->syscall_state
;
1863 ourstatus
->value
.syscall_number
= syscall_number
;
1865 if (debug_linux_nat
)
1866 fprintf_unfiltered (gdb_stdlog
,
1867 "LHST: stopping for %s of syscall %d"
1870 == TARGET_WAITKIND_SYSCALL_ENTRY
1871 ? "entry" : "return",
1877 if (debug_linux_nat
)
1878 fprintf_unfiltered (gdb_stdlog
,
1879 "LHST: ignoring %s of syscall %d "
1881 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1882 ? "entry" : "return",
1888 /* If we had been syscall tracing, and hence used PT_SYSCALL
1889 before on this LWP, it could happen that the user removes all
1890 syscall catchpoints before we get to process this event.
1891 There are two noteworthy issues here:
1893 - When stopped at a syscall entry event, resuming with
1894 PT_STEP still resumes executing the syscall and reports a
1897 - Only PT_SYSCALL catches syscall enters. If we last
1898 single-stepped this thread, then this event can't be a
1899 syscall enter. If we last single-stepped this thread, this
1900 has to be a syscall exit.
1902 The points above mean that the next resume, be it PT_STEP or
1903 PT_CONTINUE, can not trigger a syscall trace event. */
1904 if (debug_linux_nat
)
1905 fprintf_unfiltered (gdb_stdlog
,
1906 "LHST: caught syscall event "
1907 "with no syscall catchpoints."
1908 " %d for LWP %ld, ignoring\n",
1911 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1914 /* The core isn't interested in this event. For efficiency, avoid
1915 stopping all threads only to have the core resume them all again.
1916 Since we're not stopping threads, if we're still syscall tracing
1917 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1918 subsequent syscall. Simply resume using the inf-ptrace layer,
1919 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1921 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
1925 /* Handle a GNU/Linux extended wait response. If we see a clone
1926 event, we need to add the new LWP to our list (and not report the
1927 trap to higher layers). This function returns non-zero if the
1928 event should be ignored and we should wait again. If STOPPING is
1929 true, the new LWP remains stopped, otherwise it is continued. */
1932 linux_handle_extended_wait (struct lwp_info
*lp
, int status
)
1934 int pid
= lp
->ptid
.lwp ();
1935 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1936 int event
= linux_ptrace_get_extended_event (status
);
1938 /* All extended events we currently use are mid-syscall. Only
1939 PTRACE_EVENT_STOP is delivered more like a signal-stop, but
1940 you have to be using PTRACE_SEIZE to get that. */
1941 lp
->syscall_state
= TARGET_WAITKIND_SYSCALL_ENTRY
;
1943 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1944 || event
== PTRACE_EVENT_CLONE
)
1946 unsigned long new_pid
;
1949 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1951 /* If we haven't already seen the new PID stop, wait for it now. */
1952 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1954 /* The new child has a pending SIGSTOP. We can't affect it until it
1955 hits the SIGSTOP, but we're already attached. */
1956 ret
= my_waitpid (new_pid
, &status
, __WALL
);
1958 perror_with_name (_("waiting for new child"));
1959 else if (ret
!= new_pid
)
1960 internal_error (__FILE__
, __LINE__
,
1961 _("wait returned unexpected PID %d"), ret
);
1962 else if (!WIFSTOPPED (status
))
1963 internal_error (__FILE__
, __LINE__
,
1964 _("wait returned unexpected status 0x%x"), status
);
1967 ourstatus
->value
.related_pid
= ptid_t (new_pid
, new_pid
, 0);
1969 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
1971 /* The arch-specific native code may need to know about new
1972 forks even if those end up never mapped to an
1974 linux_target
->low_new_fork (lp
, new_pid
);
1977 if (event
== PTRACE_EVENT_FORK
1978 && linux_fork_checkpointing_p (lp
->ptid
.pid ()))
1980 /* Handle checkpointing by linux-fork.c here as a special
1981 case. We don't want the follow-fork-mode or 'catch fork'
1982 to interfere with this. */
1984 /* This won't actually modify the breakpoint list, but will
1985 physically remove the breakpoints from the child. */
1986 detach_breakpoints (ptid_t (new_pid
, new_pid
, 0));
1988 /* Retain child fork in ptrace (stopped) state. */
1989 if (!find_fork_pid (new_pid
))
1992 /* Report as spurious, so that infrun doesn't want to follow
1993 this fork. We're actually doing an infcall in
1995 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
1997 /* Report the stop to the core. */
2001 if (event
== PTRACE_EVENT_FORK
)
2002 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
2003 else if (event
== PTRACE_EVENT_VFORK
)
2004 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
2005 else if (event
== PTRACE_EVENT_CLONE
)
2007 struct lwp_info
*new_lp
;
2009 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2011 if (debug_linux_nat
)
2012 fprintf_unfiltered (gdb_stdlog
,
2013 "LHEW: Got clone event "
2014 "from LWP %d, new child is LWP %ld\n",
2017 new_lp
= add_lwp (ptid_t (lp
->ptid
.pid (), new_pid
, 0));
2018 new_lp
->stopped
= 1;
2019 new_lp
->resumed
= 1;
2021 /* If the thread_db layer is active, let it record the user
2022 level thread id and status, and add the thread to GDB's
2024 if (!thread_db_notice_clone (lp
->ptid
, new_lp
->ptid
))
2026 /* The process is not using thread_db. Add the LWP to
2028 target_post_attach (new_lp
->ptid
.lwp ());
2029 add_thread (new_lp
->ptid
);
2032 /* Even if we're stopping the thread for some reason
2033 internal to this module, from the perspective of infrun
2034 and the user/frontend, this new thread is running until
2035 it next reports a stop. */
2036 set_running (new_lp
->ptid
, 1);
2037 set_executing (new_lp
->ptid
, 1);
2039 if (WSTOPSIG (status
) != SIGSTOP
)
2041 /* This can happen if someone starts sending signals to
2042 the new thread before it gets a chance to run, which
2043 have a lower number than SIGSTOP (e.g. SIGUSR1).
2044 This is an unlikely case, and harder to handle for
2045 fork / vfork than for clone, so we do not try - but
2046 we handle it for clone events here. */
2048 new_lp
->signalled
= 1;
2050 /* We created NEW_LP so it cannot yet contain STATUS. */
2051 gdb_assert (new_lp
->status
== 0);
2053 /* Save the wait status to report later. */
2054 if (debug_linux_nat
)
2055 fprintf_unfiltered (gdb_stdlog
,
2056 "LHEW: waitpid of new LWP %ld, "
2057 "saving status %s\n",
2058 (long) new_lp
->ptid
.lwp (),
2059 status_to_str (status
));
2060 new_lp
->status
= status
;
2062 else if (report_thread_events
)
2064 new_lp
->waitstatus
.kind
= TARGET_WAITKIND_THREAD_CREATED
;
2065 new_lp
->status
= status
;
2074 if (event
== PTRACE_EVENT_EXEC
)
2076 if (debug_linux_nat
)
2077 fprintf_unfiltered (gdb_stdlog
,
2078 "LHEW: Got exec event from LWP %ld\n",
2081 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2082 ourstatus
->value
.execd_pathname
2083 = xstrdup (linux_proc_pid_to_exec_file (pid
));
2085 /* The thread that execed must have been resumed, but, when a
2086 thread execs, it changes its tid to the tgid, and the old
2087 tgid thread might have not been resumed. */
2092 if (event
== PTRACE_EVENT_VFORK_DONE
)
2094 if (current_inferior ()->waiting_for_vfork_done
)
2096 if (debug_linux_nat
)
2097 fprintf_unfiltered (gdb_stdlog
,
2098 "LHEW: Got expected PTRACE_EVENT_"
2099 "VFORK_DONE from LWP %ld: stopping\n",
2102 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2106 if (debug_linux_nat
)
2107 fprintf_unfiltered (gdb_stdlog
,
2108 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2109 "from LWP %ld: ignoring\n",
2114 internal_error (__FILE__
, __LINE__
,
2115 _("unknown ptrace event %d"), event
);
2118 /* Suspend waiting for a signal. We're mostly interested in
2124 if (debug_linux_nat
)
2125 fprintf_unfiltered (gdb_stdlog
, "linux-nat: about to sigsuspend\n");
2126 sigsuspend (&suspend_mask
);
2128 /* If the quit flag is set, it means that the user pressed Ctrl-C
2129 and we're debugging a process that is running on a separate
2130 terminal, so we must forward the Ctrl-C to the inferior. (If the
2131 inferior is sharing GDB's terminal, then the Ctrl-C reaches the
2132 inferior directly.) We must do this here because functions that
2133 need to block waiting for a signal loop forever until there's an
2134 event to report before returning back to the event loop. */
2135 if (!target_terminal::is_ours ())
2137 if (check_quit_flag ())
2138 target_pass_ctrlc ();
2142 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2146 wait_lwp (struct lwp_info
*lp
)
2150 int thread_dead
= 0;
2153 gdb_assert (!lp
->stopped
);
2154 gdb_assert (lp
->status
== 0);
2156 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2157 block_child_signals (&prev_mask
);
2161 pid
= my_waitpid (lp
->ptid
.lwp (), &status
, __WALL
| WNOHANG
);
2162 if (pid
== -1 && errno
== ECHILD
)
2164 /* The thread has previously exited. We need to delete it
2165 now because if this was a non-leader thread execing, we
2166 won't get an exit event. See comments on exec events at
2167 the top of the file. */
2169 if (debug_linux_nat
)
2170 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2171 target_pid_to_str (lp
->ptid
).c_str ());
2176 /* Bugs 10970, 12702.
2177 Thread group leader may have exited in which case we'll lock up in
2178 waitpid if there are other threads, even if they are all zombies too.
2179 Basically, we're not supposed to use waitpid this way.
2180 tkill(pid,0) cannot be used here as it gets ESRCH for both
2181 for zombie and running processes.
2183 As a workaround, check if we're waiting for the thread group leader and
2184 if it's a zombie, and avoid calling waitpid if it is.
2186 This is racy, what if the tgl becomes a zombie right after we check?
2187 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2188 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2190 if (lp
->ptid
.pid () == lp
->ptid
.lwp ()
2191 && linux_proc_pid_is_zombie (lp
->ptid
.lwp ()))
2194 if (debug_linux_nat
)
2195 fprintf_unfiltered (gdb_stdlog
,
2196 "WL: Thread group leader %s vanished.\n",
2197 target_pid_to_str (lp
->ptid
).c_str ());
2201 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2202 get invoked despite our caller had them intentionally blocked by
2203 block_child_signals. This is sensitive only to the loop of
2204 linux_nat_wait_1 and there if we get called my_waitpid gets called
2205 again before it gets to sigsuspend so we can safely let the handlers
2206 get executed here. */
2210 restore_child_signals_mask (&prev_mask
);
2214 gdb_assert (pid
== lp
->ptid
.lwp ());
2216 if (debug_linux_nat
)
2218 fprintf_unfiltered (gdb_stdlog
,
2219 "WL: waitpid %s received %s\n",
2220 target_pid_to_str (lp
->ptid
).c_str (),
2221 status_to_str (status
));
2224 /* Check if the thread has exited. */
2225 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2227 if (report_thread_events
2228 || lp
->ptid
.pid () == lp
->ptid
.lwp ())
2230 if (debug_linux_nat
)
2231 fprintf_unfiltered (gdb_stdlog
, "WL: LWP %d exited.\n",
2234 /* If this is the leader exiting, it means the whole
2235 process is gone. Store the status to report to the
2236 core. Store it in lp->waitstatus, because lp->status
2237 would be ambiguous (W_EXITCODE(0,0) == 0). */
2238 store_waitstatus (&lp
->waitstatus
, status
);
2243 if (debug_linux_nat
)
2244 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2245 target_pid_to_str (lp
->ptid
).c_str ());
2255 gdb_assert (WIFSTOPPED (status
));
2258 if (lp
->must_set_ptrace_flags
)
2260 struct inferior
*inf
= find_inferior_pid (lp
->ptid
.pid ());
2261 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2263 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2264 lp
->must_set_ptrace_flags
= 0;
2267 /* Handle GNU/Linux's syscall SIGTRAPs. */
2268 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2270 /* No longer need the sysgood bit. The ptrace event ends up
2271 recorded in lp->waitstatus if we care for it. We can carry
2272 on handling the event like a regular SIGTRAP from here
2274 status
= W_STOPCODE (SIGTRAP
);
2275 if (linux_handle_syscall_trap (lp
, 1))
2276 return wait_lwp (lp
);
2280 /* Almost all other ptrace-stops are known to be outside of system
2281 calls, with further exceptions in linux_handle_extended_wait. */
2282 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
2285 /* Handle GNU/Linux's extended waitstatus for trace events. */
2286 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2287 && linux_is_extended_waitstatus (status
))
2289 if (debug_linux_nat
)
2290 fprintf_unfiltered (gdb_stdlog
,
2291 "WL: Handling extended status 0x%06x\n",
2293 linux_handle_extended_wait (lp
, status
);
2300 /* Send a SIGSTOP to LP. */
2303 stop_callback (struct lwp_info
*lp
)
2305 if (!lp
->stopped
&& !lp
->signalled
)
2309 if (debug_linux_nat
)
2311 fprintf_unfiltered (gdb_stdlog
,
2312 "SC: kill %s **<SIGSTOP>**\n",
2313 target_pid_to_str (lp
->ptid
).c_str ());
2316 ret
= kill_lwp (lp
->ptid
.lwp (), SIGSTOP
);
2317 if (debug_linux_nat
)
2319 fprintf_unfiltered (gdb_stdlog
,
2320 "SC: lwp kill %d %s\n",
2322 errno
? safe_strerror (errno
) : "ERRNO-OK");
2326 gdb_assert (lp
->status
== 0);
2332 /* Request a stop on LWP. */
2335 linux_stop_lwp (struct lwp_info
*lwp
)
2337 stop_callback (lwp
);
2340 /* See linux-nat.h */
2343 linux_stop_and_wait_all_lwps (void)
2345 /* Stop all LWP's ... */
2346 iterate_over_lwps (minus_one_ptid
, stop_callback
);
2348 /* ... and wait until all of them have reported back that
2349 they're no longer running. */
2350 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
);
2353 /* See linux-nat.h */
2356 linux_unstop_all_lwps (void)
2358 iterate_over_lwps (minus_one_ptid
,
2359 [] (struct lwp_info
*info
)
2361 return resume_stopped_resumed_lwps (info
, minus_one_ptid
);
2365 /* Return non-zero if LWP PID has a pending SIGINT. */
2368 linux_nat_has_pending_sigint (int pid
)
2370 sigset_t pending
, blocked
, ignored
;
2372 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2374 if (sigismember (&pending
, SIGINT
)
2375 && !sigismember (&ignored
, SIGINT
))
2381 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2384 set_ignore_sigint (struct lwp_info
*lp
)
2386 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2387 flag to consume the next one. */
2388 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2389 && WSTOPSIG (lp
->status
) == SIGINT
)
2392 lp
->ignore_sigint
= 1;
2397 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2398 This function is called after we know the LWP has stopped; if the LWP
2399 stopped before the expected SIGINT was delivered, then it will never have
2400 arrived. Also, if the signal was delivered to a shared queue and consumed
2401 by a different thread, it will never be delivered to this LWP. */
2404 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2406 if (!lp
->ignore_sigint
)
2409 if (!linux_nat_has_pending_sigint (lp
->ptid
.lwp ()))
2411 if (debug_linux_nat
)
2412 fprintf_unfiltered (gdb_stdlog
,
2413 "MCIS: Clearing bogus flag for %s\n",
2414 target_pid_to_str (lp
->ptid
).c_str ());
2415 lp
->ignore_sigint
= 0;
2419 /* Fetch the possible triggered data watchpoint info and store it in
2422 On some archs, like x86, that use debug registers to set
2423 watchpoints, it's possible that the way to know which watched
2424 address trapped, is to check the register that is used to select
2425 which address to watch. Problem is, between setting the watchpoint
2426 and reading back which data address trapped, the user may change
2427 the set of watchpoints, and, as a consequence, GDB changes the
2428 debug registers in the inferior. To avoid reading back a stale
2429 stopped-data-address when that happens, we cache in LP the fact
2430 that a watchpoint trapped, and the corresponding data address, as
2431 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2432 registers meanwhile, we have the cached data we can rely on. */
2435 check_stopped_by_watchpoint (struct lwp_info
*lp
)
2437 scoped_restore save_inferior_ptid
= make_scoped_restore (&inferior_ptid
);
2438 inferior_ptid
= lp
->ptid
;
2440 if (linux_target
->low_stopped_by_watchpoint ())
2442 lp
->stop_reason
= TARGET_STOPPED_BY_WATCHPOINT
;
2443 lp
->stopped_data_address_p
2444 = linux_target
->low_stopped_data_address (&lp
->stopped_data_address
);
2447 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2450 /* Returns true if the LWP had stopped for a watchpoint. */
2453 linux_nat_target::stopped_by_watchpoint ()
2455 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2457 gdb_assert (lp
!= NULL
);
2459 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2463 linux_nat_target::stopped_data_address (CORE_ADDR
*addr_p
)
2465 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2467 gdb_assert (lp
!= NULL
);
2469 *addr_p
= lp
->stopped_data_address
;
2471 return lp
->stopped_data_address_p
;
2474 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2477 linux_nat_target::low_status_is_event (int status
)
2479 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2482 /* Wait until LP is stopped. */
2485 stop_wait_callback (struct lwp_info
*lp
)
2487 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
2489 /* If this is a vfork parent, bail out, it is not going to report
2490 any SIGSTOP until the vfork is done with. */
2491 if (inf
->vfork_child
!= NULL
)
2498 status
= wait_lwp (lp
);
2502 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2503 && WSTOPSIG (status
) == SIGINT
)
2505 lp
->ignore_sigint
= 0;
2508 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
2510 if (debug_linux_nat
)
2511 fprintf_unfiltered (gdb_stdlog
,
2512 "PTRACE_CONT %s, 0, 0 (%s) "
2513 "(discarding SIGINT)\n",
2514 target_pid_to_str (lp
->ptid
).c_str (),
2515 errno
? safe_strerror (errno
) : "OK");
2517 return stop_wait_callback (lp
);
2520 maybe_clear_ignore_sigint (lp
);
2522 if (WSTOPSIG (status
) != SIGSTOP
)
2524 /* The thread was stopped with a signal other than SIGSTOP. */
2526 if (debug_linux_nat
)
2527 fprintf_unfiltered (gdb_stdlog
,
2528 "SWC: Pending event %s in %s\n",
2529 status_to_str ((int) status
),
2530 target_pid_to_str (lp
->ptid
).c_str ());
2532 /* Save the sigtrap event. */
2533 lp
->status
= status
;
2534 gdb_assert (lp
->signalled
);
2535 save_stop_reason (lp
);
2539 /* We caught the SIGSTOP that we intended to catch. */
2541 if (debug_linux_nat
)
2542 fprintf_unfiltered (gdb_stdlog
,
2543 "SWC: Expected SIGSTOP caught for %s.\n",
2544 target_pid_to_str (lp
->ptid
).c_str ());
2548 /* If we are waiting for this stop so we can report the thread
2549 stopped then we need to record this status. Otherwise, we can
2550 now discard this stop event. */
2551 if (lp
->last_resume_kind
== resume_stop
)
2553 lp
->status
= status
;
2554 save_stop_reason (lp
);
2562 /* Return non-zero if LP has a wait status pending. Discard the
2563 pending event and resume the LWP if the event that originally
2564 caused the stop became uninteresting. */
2567 status_callback (struct lwp_info
*lp
)
2569 /* Only report a pending wait status if we pretend that this has
2570 indeed been resumed. */
2574 if (!lwp_status_pending_p (lp
))
2577 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
2578 || lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2580 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2584 pc
= regcache_read_pc (regcache
);
2586 if (pc
!= lp
->stop_pc
)
2588 if (debug_linux_nat
)
2589 fprintf_unfiltered (gdb_stdlog
,
2590 "SC: PC of %s changed. was=%s, now=%s\n",
2591 target_pid_to_str (lp
->ptid
).c_str (),
2592 paddress (target_gdbarch (), lp
->stop_pc
),
2593 paddress (target_gdbarch (), pc
));
2597 #if !USE_SIGTRAP_SIGINFO
2598 else if (!breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2600 if (debug_linux_nat
)
2601 fprintf_unfiltered (gdb_stdlog
,
2602 "SC: previous breakpoint of %s, at %s gone\n",
2603 target_pid_to_str (lp
->ptid
).c_str (),
2604 paddress (target_gdbarch (), lp
->stop_pc
));
2612 if (debug_linux_nat
)
2613 fprintf_unfiltered (gdb_stdlog
,
2614 "SC: pending event of %s cancelled.\n",
2615 target_pid_to_str (lp
->ptid
).c_str ());
2618 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2626 /* Count the LWP's that have had events. */
2629 count_events_callback (struct lwp_info
*lp
, int *count
)
2631 gdb_assert (count
!= NULL
);
2633 /* Select only resumed LWPs that have an event pending. */
2634 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2640 /* Select the LWP (if any) that is currently being single-stepped. */
2643 select_singlestep_lwp_callback (struct lwp_info
*lp
)
2645 if (lp
->last_resume_kind
== resume_step
2652 /* Returns true if LP has a status pending. */
2655 lwp_status_pending_p (struct lwp_info
*lp
)
2657 /* We check for lp->waitstatus in addition to lp->status, because we
2658 can have pending process exits recorded in lp->status and
2659 W_EXITCODE(0,0) happens to be 0. */
2660 return lp
->status
!= 0 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
;
2663 /* Select the Nth LWP that has had an event. */
2666 select_event_lwp_callback (struct lwp_info
*lp
, int *selector
)
2668 gdb_assert (selector
!= NULL
);
2670 /* Select only resumed LWPs that have an event pending. */
2671 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2672 if ((*selector
)-- == 0)
2678 /* Called when the LWP stopped for a signal/trap. If it stopped for a
2679 trap check what caused it (breakpoint, watchpoint, trace, etc.),
2680 and save the result in the LWP's stop_reason field. If it stopped
2681 for a breakpoint, decrement the PC if necessary on the lwp's
2685 save_stop_reason (struct lwp_info
*lp
)
2687 struct regcache
*regcache
;
2688 struct gdbarch
*gdbarch
;
2691 #if USE_SIGTRAP_SIGINFO
2695 gdb_assert (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
);
2696 gdb_assert (lp
->status
!= 0);
2698 if (!linux_target
->low_status_is_event (lp
->status
))
2701 regcache
= get_thread_regcache (lp
->ptid
);
2702 gdbarch
= regcache
->arch ();
2704 pc
= regcache_read_pc (regcache
);
2705 sw_bp_pc
= pc
- gdbarch_decr_pc_after_break (gdbarch
);
2707 #if USE_SIGTRAP_SIGINFO
2708 if (linux_nat_get_siginfo (lp
->ptid
, &siginfo
))
2710 if (siginfo
.si_signo
== SIGTRAP
)
2712 if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
)
2713 && GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2715 /* The si_code is ambiguous on this arch -- check debug
2717 if (!check_stopped_by_watchpoint (lp
))
2718 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2720 else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
))
2722 /* If we determine the LWP stopped for a SW breakpoint,
2723 trust it. Particularly don't check watchpoint
2724 registers, because at least on s390, we'd find
2725 stopped-by-watchpoint as long as there's a watchpoint
2727 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2729 else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2731 /* This can indicate either a hardware breakpoint or
2732 hardware watchpoint. Check debug registers. */
2733 if (!check_stopped_by_watchpoint (lp
))
2734 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2736 else if (siginfo
.si_code
== TRAP_TRACE
)
2738 if (debug_linux_nat
)
2739 fprintf_unfiltered (gdb_stdlog
,
2740 "CSBB: %s stopped by trace\n",
2741 target_pid_to_str (lp
->ptid
).c_str ());
2743 /* We may have single stepped an instruction that
2744 triggered a watchpoint. In that case, on some
2745 architectures (such as x86), instead of TRAP_HWBKPT,
2746 si_code indicates TRAP_TRACE, and we need to check
2747 the debug registers separately. */
2748 check_stopped_by_watchpoint (lp
);
2753 if ((!lp
->step
|| lp
->stop_pc
== sw_bp_pc
)
2754 && software_breakpoint_inserted_here_p (regcache
->aspace (),
2757 /* The LWP was either continued, or stepped a software
2758 breakpoint instruction. */
2759 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2762 if (hardware_breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2763 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2765 if (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
)
2766 check_stopped_by_watchpoint (lp
);
2769 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
)
2771 if (debug_linux_nat
)
2772 fprintf_unfiltered (gdb_stdlog
,
2773 "CSBB: %s stopped by software breakpoint\n",
2774 target_pid_to_str (lp
->ptid
).c_str ());
2776 /* Back up the PC if necessary. */
2778 regcache_write_pc (regcache
, sw_bp_pc
);
2780 /* Update this so we record the correct stop PC below. */
2783 else if (lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2785 if (debug_linux_nat
)
2786 fprintf_unfiltered (gdb_stdlog
,
2787 "CSBB: %s stopped by hardware breakpoint\n",
2788 target_pid_to_str (lp
->ptid
).c_str ());
2790 else if (lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
)
2792 if (debug_linux_nat
)
2793 fprintf_unfiltered (gdb_stdlog
,
2794 "CSBB: %s stopped by hardware watchpoint\n",
2795 target_pid_to_str (lp
->ptid
).c_str ());
2802 /* Returns true if the LWP had stopped for a software breakpoint. */
2805 linux_nat_target::stopped_by_sw_breakpoint ()
2807 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2809 gdb_assert (lp
!= NULL
);
2811 return lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
;
2814 /* Implement the supports_stopped_by_sw_breakpoint method. */
2817 linux_nat_target::supports_stopped_by_sw_breakpoint ()
2819 return USE_SIGTRAP_SIGINFO
;
2822 /* Returns true if the LWP had stopped for a hardware
2823 breakpoint/watchpoint. */
2826 linux_nat_target::stopped_by_hw_breakpoint ()
2828 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2830 gdb_assert (lp
!= NULL
);
2832 return lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
;
2835 /* Implement the supports_stopped_by_hw_breakpoint method. */
2838 linux_nat_target::supports_stopped_by_hw_breakpoint ()
2840 return USE_SIGTRAP_SIGINFO
;
2843 /* Select one LWP out of those that have events pending. */
2846 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2849 int random_selector
;
2850 struct lwp_info
*event_lp
= NULL
;
2852 /* Record the wait status for the original LWP. */
2853 (*orig_lp
)->status
= *status
;
2855 /* In all-stop, give preference to the LWP that is being
2856 single-stepped. There will be at most one, and it will be the
2857 LWP that the core is most interested in. If we didn't do this,
2858 then we'd have to handle pending step SIGTRAPs somehow in case
2859 the core later continues the previously-stepped thread, as
2860 otherwise we'd report the pending SIGTRAP then, and the core, not
2861 having stepped the thread, wouldn't understand what the trap was
2862 for, and therefore would report it to the user as a random
2864 if (!target_is_non_stop_p ())
2866 event_lp
= iterate_over_lwps (filter
, select_singlestep_lwp_callback
);
2867 if (event_lp
!= NULL
)
2869 if (debug_linux_nat
)
2870 fprintf_unfiltered (gdb_stdlog
,
2871 "SEL: Select single-step %s\n",
2872 target_pid_to_str (event_lp
->ptid
).c_str ());
2876 if (event_lp
== NULL
)
2878 /* Pick one at random, out of those which have had events. */
2880 /* First see how many events we have. */
2881 iterate_over_lwps (filter
,
2882 [&] (struct lwp_info
*info
)
2884 return count_events_callback (info
, &num_events
);
2886 gdb_assert (num_events
> 0);
2888 /* Now randomly pick a LWP out of those that have had
2890 random_selector
= (int)
2891 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2893 if (debug_linux_nat
&& num_events
> 1)
2894 fprintf_unfiltered (gdb_stdlog
,
2895 "SEL: Found %d events, selecting #%d\n",
2896 num_events
, random_selector
);
2899 = (iterate_over_lwps
2901 [&] (struct lwp_info
*info
)
2903 return select_event_lwp_callback (info
,
2908 if (event_lp
!= NULL
)
2910 /* Switch the event LWP. */
2911 *orig_lp
= event_lp
;
2912 *status
= event_lp
->status
;
2915 /* Flush the wait status for the event LWP. */
2916 (*orig_lp
)->status
= 0;
2919 /* Return non-zero if LP has been resumed. */
2922 resumed_callback (struct lwp_info
*lp
)
2927 /* Check if we should go on and pass this event to common code.
2928 Return the affected lwp if we are, or NULL otherwise. */
2930 static struct lwp_info
*
2931 linux_nat_filter_event (int lwpid
, int status
)
2933 struct lwp_info
*lp
;
2934 int event
= linux_ptrace_get_extended_event (status
);
2936 lp
= find_lwp_pid (ptid_t (lwpid
));
2938 /* Check for stop events reported by a process we didn't already
2939 know about - anything not already in our LWP list.
2941 If we're expecting to receive stopped processes after
2942 fork, vfork, and clone events, then we'll just add the
2943 new one to our list and go back to waiting for the event
2944 to be reported - the stopped process might be returned
2945 from waitpid before or after the event is.
2947 But note the case of a non-leader thread exec'ing after the
2948 leader having exited, and gone from our lists. The non-leader
2949 thread changes its tid to the tgid. */
2951 if (WIFSTOPPED (status
) && lp
== NULL
2952 && (WSTOPSIG (status
) == SIGTRAP
&& event
== PTRACE_EVENT_EXEC
))
2954 /* A multi-thread exec after we had seen the leader exiting. */
2955 if (debug_linux_nat
)
2956 fprintf_unfiltered (gdb_stdlog
,
2957 "LLW: Re-adding thread group leader LWP %d.\n",
2960 lp
= add_lwp (ptid_t (lwpid
, lwpid
, 0));
2963 add_thread (lp
->ptid
);
2966 if (WIFSTOPPED (status
) && !lp
)
2968 if (debug_linux_nat
)
2969 fprintf_unfiltered (gdb_stdlog
,
2970 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2971 (long) lwpid
, status_to_str (status
));
2972 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2976 /* Make sure we don't report an event for the exit of an LWP not in
2977 our list, i.e. not part of the current process. This can happen
2978 if we detach from a program we originally forked and then it
2980 if (!WIFSTOPPED (status
) && !lp
)
2983 /* This LWP is stopped now. (And if dead, this prevents it from
2984 ever being continued.) */
2987 if (WIFSTOPPED (status
) && lp
->must_set_ptrace_flags
)
2989 struct inferior
*inf
= find_inferior_pid (lp
->ptid
.pid ());
2990 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2992 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2993 lp
->must_set_ptrace_flags
= 0;
2996 /* Handle GNU/Linux's syscall SIGTRAPs. */
2997 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2999 /* No longer need the sysgood bit. The ptrace event ends up
3000 recorded in lp->waitstatus if we care for it. We can carry
3001 on handling the event like a regular SIGTRAP from here
3003 status
= W_STOPCODE (SIGTRAP
);
3004 if (linux_handle_syscall_trap (lp
, 0))
3009 /* Almost all other ptrace-stops are known to be outside of system
3010 calls, with further exceptions in linux_handle_extended_wait. */
3011 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
3014 /* Handle GNU/Linux's extended waitstatus for trace events. */
3015 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
3016 && linux_is_extended_waitstatus (status
))
3018 if (debug_linux_nat
)
3019 fprintf_unfiltered (gdb_stdlog
,
3020 "LLW: Handling extended status 0x%06x\n",
3022 if (linux_handle_extended_wait (lp
, status
))
3026 /* Check if the thread has exited. */
3027 if (WIFEXITED (status
) || WIFSIGNALED (status
))
3029 if (!report_thread_events
3030 && num_lwps (lp
->ptid
.pid ()) > 1)
3032 if (debug_linux_nat
)
3033 fprintf_unfiltered (gdb_stdlog
,
3034 "LLW: %s exited.\n",
3035 target_pid_to_str (lp
->ptid
).c_str ());
3037 /* If there is at least one more LWP, then the exit signal
3038 was not the end of the debugged application and should be
3044 /* Note that even if the leader was ptrace-stopped, it can still
3045 exit, if e.g., some other thread brings down the whole
3046 process (calls `exit'). So don't assert that the lwp is
3048 if (debug_linux_nat
)
3049 fprintf_unfiltered (gdb_stdlog
,
3050 "LWP %ld exited (resumed=%d)\n",
3051 lp
->ptid
.lwp (), lp
->resumed
);
3053 /* Dead LWP's aren't expected to reported a pending sigstop. */
3056 /* Store the pending event in the waitstatus, because
3057 W_EXITCODE(0,0) == 0. */
3058 store_waitstatus (&lp
->waitstatus
, status
);
3062 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3063 an attempt to stop an LWP. */
3065 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3069 if (lp
->last_resume_kind
== resume_stop
)
3071 if (debug_linux_nat
)
3072 fprintf_unfiltered (gdb_stdlog
,
3073 "LLW: resume_stop SIGSTOP caught for %s.\n",
3074 target_pid_to_str (lp
->ptid
).c_str ());
3078 /* This is a delayed SIGSTOP. Filter out the event. */
3080 if (debug_linux_nat
)
3081 fprintf_unfiltered (gdb_stdlog
,
3082 "LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
3084 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3085 target_pid_to_str (lp
->ptid
).c_str ());
3087 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3088 gdb_assert (lp
->resumed
);
3093 /* Make sure we don't report a SIGINT that we have already displayed
3094 for another thread. */
3095 if (lp
->ignore_sigint
3096 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3098 if (debug_linux_nat
)
3099 fprintf_unfiltered (gdb_stdlog
,
3100 "LLW: Delayed SIGINT caught for %s.\n",
3101 target_pid_to_str (lp
->ptid
).c_str ());
3103 /* This is a delayed SIGINT. */
3104 lp
->ignore_sigint
= 0;
3106 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3107 if (debug_linux_nat
)
3108 fprintf_unfiltered (gdb_stdlog
,
3109 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3111 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3112 target_pid_to_str (lp
->ptid
).c_str ());
3113 gdb_assert (lp
->resumed
);
3115 /* Discard the event. */
3119 /* Don't report signals that GDB isn't interested in, such as
3120 signals that are neither printed nor stopped upon. Stopping all
3121 threads can be a bit time-consuming so if we want decent
3122 performance with heavily multi-threaded programs, especially when
3123 they're using a high frequency timer, we'd better avoid it if we
3125 if (WIFSTOPPED (status
))
3127 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3129 if (!target_is_non_stop_p ())
3131 /* Only do the below in all-stop, as we currently use SIGSTOP
3132 to implement target_stop (see linux_nat_stop) in
3134 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3136 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3137 forwarded to the entire process group, that is, all LWPs
3138 will receive it - unless they're using CLONE_THREAD to
3139 share signals. Since we only want to report it once, we
3140 mark it as ignored for all LWPs except this one. */
3141 iterate_over_lwps (ptid_t (lp
->ptid
.pid ()), set_ignore_sigint
);
3142 lp
->ignore_sigint
= 0;
3145 maybe_clear_ignore_sigint (lp
);
3148 /* When using hardware single-step, we need to report every signal.
3149 Otherwise, signals in pass_mask may be short-circuited
3150 except signals that might be caused by a breakpoint. */
3152 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
))
3153 && !linux_wstatus_maybe_breakpoint (status
))
3155 linux_resume_one_lwp (lp
, lp
->step
, signo
);
3156 if (debug_linux_nat
)
3157 fprintf_unfiltered (gdb_stdlog
,
3158 "LLW: %s %s, %s (preempt 'handle')\n",
3160 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3161 target_pid_to_str (lp
->ptid
).c_str (),
3162 (signo
!= GDB_SIGNAL_0
3163 ? strsignal (gdb_signal_to_host (signo
))
3169 /* An interesting event. */
3171 lp
->status
= status
;
3172 save_stop_reason (lp
);
3176 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3177 their exits until all other threads in the group have exited. */
3180 check_zombie_leaders (void)
3182 for (inferior
*inf
: all_inferiors ())
3184 struct lwp_info
*leader_lp
;
3189 leader_lp
= find_lwp_pid (ptid_t (inf
->pid
));
3190 if (leader_lp
!= NULL
3191 /* Check if there are other threads in the group, as we may
3192 have raced with the inferior simply exiting. */
3193 && num_lwps (inf
->pid
) > 1
3194 && linux_proc_pid_is_zombie (inf
->pid
))
3196 if (debug_linux_nat
)
3197 fprintf_unfiltered (gdb_stdlog
,
3198 "CZL: Thread group leader %d zombie "
3199 "(it exited, or another thread execd).\n",
3202 /* A leader zombie can mean one of two things:
3204 - It exited, and there's an exit status pending
3205 available, or only the leader exited (not the whole
3206 program). In the latter case, we can't waitpid the
3207 leader's exit status until all other threads are gone.
3209 - There are 3 or more threads in the group, and a thread
3210 other than the leader exec'd. See comments on exec
3211 events at the top of the file. We could try
3212 distinguishing the exit and exec cases, by waiting once
3213 more, and seeing if something comes out, but it doesn't
3214 sound useful. The previous leader _does_ go away, and
3215 we'll re-add the new one once we see the exec event
3216 (which is just the same as what would happen if the
3217 previous leader did exit voluntarily before some other
3220 if (debug_linux_nat
)
3221 fprintf_unfiltered (gdb_stdlog
,
3222 "CZL: Thread group leader %d vanished.\n",
3224 exit_lwp (leader_lp
);
3229 /* Convenience function that is called when the kernel reports an exit
3230 event. This decides whether to report the event to GDB as a
3231 process exit event, a thread exit event, or to suppress the
3235 filter_exit_event (struct lwp_info
*event_child
,
3236 struct target_waitstatus
*ourstatus
)
3238 ptid_t ptid
= event_child
->ptid
;
3240 if (num_lwps (ptid
.pid ()) > 1)
3242 if (report_thread_events
)
3243 ourstatus
->kind
= TARGET_WAITKIND_THREAD_EXITED
;
3245 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3247 exit_lwp (event_child
);
3254 linux_nat_wait_1 (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3258 enum resume_kind last_resume_kind
;
3259 struct lwp_info
*lp
;
3262 if (debug_linux_nat
)
3263 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3265 /* The first time we get here after starting a new inferior, we may
3266 not have added it to the LWP list yet - this is the earliest
3267 moment at which we know its PID. */
3268 if (inferior_ptid
.is_pid ())
3270 /* Upgrade the main thread's ptid. */
3271 thread_change_ptid (inferior_ptid
,
3272 ptid_t (inferior_ptid
.pid (),
3273 inferior_ptid
.pid (), 0));
3275 lp
= add_initial_lwp (inferior_ptid
);
3279 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3280 block_child_signals (&prev_mask
);
3282 /* First check if there is a LWP with a wait status pending. */
3283 lp
= iterate_over_lwps (ptid
, status_callback
);
3286 if (debug_linux_nat
)
3287 fprintf_unfiltered (gdb_stdlog
,
3288 "LLW: Using pending wait status %s for %s.\n",
3289 status_to_str (lp
->status
),
3290 target_pid_to_str (lp
->ptid
).c_str ());
3293 /* But if we don't find a pending event, we'll have to wait. Always
3294 pull all events out of the kernel. We'll randomly select an
3295 event LWP out of all that have events, to prevent starvation. */
3301 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3304 - If the thread group leader exits while other threads in the
3305 thread group still exist, waitpid(TGID, ...) hangs. That
3306 waitpid won't return an exit status until the other threads
3307 in the group are reapped.
3309 - When a non-leader thread execs, that thread just vanishes
3310 without reporting an exit (so we'd hang if we waited for it
3311 explicitly in that case). The exec event is reported to
3315 lwpid
= my_waitpid (-1, &status
, __WALL
| WNOHANG
);
3317 if (debug_linux_nat
)
3318 fprintf_unfiltered (gdb_stdlog
,
3319 "LNW: waitpid(-1, ...) returned %d, %s\n",
3320 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3324 if (debug_linux_nat
)
3326 fprintf_unfiltered (gdb_stdlog
,
3327 "LLW: waitpid %ld received %s\n",
3328 (long) lwpid
, status_to_str (status
));
3331 linux_nat_filter_event (lwpid
, status
);
3332 /* Retry until nothing comes out of waitpid. A single
3333 SIGCHLD can indicate more than one child stopped. */
3337 /* Now that we've pulled all events out of the kernel, resume
3338 LWPs that don't have an interesting event to report. */
3339 iterate_over_lwps (minus_one_ptid
,
3340 [] (struct lwp_info
*info
)
3342 return resume_stopped_resumed_lwps (info
, minus_one_ptid
);
3345 /* ... and find an LWP with a status to report to the core, if
3347 lp
= iterate_over_lwps (ptid
, status_callback
);
3351 /* Check for zombie thread group leaders. Those can't be reaped
3352 until all other threads in the thread group are. */
3353 check_zombie_leaders ();
3355 /* If there are no resumed children left, bail. We'd be stuck
3356 forever in the sigsuspend call below otherwise. */
3357 if (iterate_over_lwps (ptid
, resumed_callback
) == NULL
)
3359 if (debug_linux_nat
)
3360 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3362 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3364 restore_child_signals_mask (&prev_mask
);
3365 return minus_one_ptid
;
3368 /* No interesting event to report to the core. */
3370 if (target_options
& TARGET_WNOHANG
)
3372 if (debug_linux_nat
)
3373 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3375 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3376 restore_child_signals_mask (&prev_mask
);
3377 return minus_one_ptid
;
3380 /* We shouldn't end up here unless we want to try again. */
3381 gdb_assert (lp
== NULL
);
3383 /* Block until we get an event reported with SIGCHLD. */
3389 status
= lp
->status
;
3392 if (!target_is_non_stop_p ())
3394 /* Now stop all other LWP's ... */
3395 iterate_over_lwps (minus_one_ptid
, stop_callback
);
3397 /* ... and wait until all of them have reported back that
3398 they're no longer running. */
3399 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
);
3402 /* If we're not waiting for a specific LWP, choose an event LWP from
3403 among those that have had events. Giving equal priority to all
3404 LWPs that have had events helps prevent starvation. */
3405 if (ptid
== minus_one_ptid
|| ptid
.is_pid ())
3406 select_event_lwp (ptid
, &lp
, &status
);
3408 gdb_assert (lp
!= NULL
);
3410 /* Now that we've selected our final event LWP, un-adjust its PC if
3411 it was a software breakpoint, and we can't reliably support the
3412 "stopped by software breakpoint" stop reason. */
3413 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
3414 && !USE_SIGTRAP_SIGINFO
)
3416 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3417 struct gdbarch
*gdbarch
= regcache
->arch ();
3418 int decr_pc
= gdbarch_decr_pc_after_break (gdbarch
);
3424 pc
= regcache_read_pc (regcache
);
3425 regcache_write_pc (regcache
, pc
+ decr_pc
);
3429 /* We'll need this to determine whether to report a SIGSTOP as
3430 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3432 last_resume_kind
= lp
->last_resume_kind
;
3434 if (!target_is_non_stop_p ())
3436 /* In all-stop, from the core's perspective, all LWPs are now
3437 stopped until a new resume action is sent over. */
3438 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
);
3442 resume_clear_callback (lp
);
3445 if (linux_target
->low_status_is_event (status
))
3447 if (debug_linux_nat
)
3448 fprintf_unfiltered (gdb_stdlog
,
3449 "LLW: trap ptid is %s.\n",
3450 target_pid_to_str (lp
->ptid
).c_str ());
3453 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3455 *ourstatus
= lp
->waitstatus
;
3456 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3459 store_waitstatus (ourstatus
, status
);
3461 if (debug_linux_nat
)
3462 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3464 restore_child_signals_mask (&prev_mask
);
3466 if (last_resume_kind
== resume_stop
3467 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3468 && WSTOPSIG (status
) == SIGSTOP
)
3470 /* A thread that has been requested to stop by GDB with
3471 target_stop, and it stopped cleanly, so report as SIG0. The
3472 use of SIGSTOP is an implementation detail. */
3473 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3476 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3477 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3480 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3482 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
)
3483 return filter_exit_event (lp
, ourstatus
);
3488 /* Resume LWPs that are currently stopped without any pending status
3489 to report, but are resumed from the core's perspective. */
3492 resume_stopped_resumed_lwps (struct lwp_info
*lp
, const ptid_t wait_ptid
)
3496 if (debug_linux_nat
)
3497 fprintf_unfiltered (gdb_stdlog
,
3498 "RSRL: NOT resuming LWP %s, not stopped\n",
3499 target_pid_to_str (lp
->ptid
).c_str ());
3501 else if (!lp
->resumed
)
3503 if (debug_linux_nat
)
3504 fprintf_unfiltered (gdb_stdlog
,
3505 "RSRL: NOT resuming LWP %s, not resumed\n",
3506 target_pid_to_str (lp
->ptid
).c_str ());
3508 else if (lwp_status_pending_p (lp
))
3510 if (debug_linux_nat
)
3511 fprintf_unfiltered (gdb_stdlog
,
3512 "RSRL: NOT resuming LWP %s, has pending status\n",
3513 target_pid_to_str (lp
->ptid
).c_str ());
3517 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3518 struct gdbarch
*gdbarch
= regcache
->arch ();
3522 CORE_ADDR pc
= regcache_read_pc (regcache
);
3523 int leave_stopped
= 0;
3525 /* Don't bother if there's a breakpoint at PC that we'd hit
3526 immediately, and we're not waiting for this LWP. */
3527 if (!lp
->ptid
.matches (wait_ptid
))
3529 if (breakpoint_inserted_here_p (regcache
->aspace (), pc
))
3535 if (debug_linux_nat
)
3536 fprintf_unfiltered (gdb_stdlog
,
3537 "RSRL: resuming stopped-resumed LWP %s at "
3539 target_pid_to_str (lp
->ptid
).c_str (),
3540 paddress (gdbarch
, pc
),
3543 linux_resume_one_lwp_throw (lp
, lp
->step
, GDB_SIGNAL_0
);
3546 catch (const gdb_exception_error
&ex
)
3548 if (!check_ptrace_stopped_lwp_gone (lp
))
3557 linux_nat_target::wait (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3562 if (debug_linux_nat
)
3564 std::string options_string
= target_options_to_string (target_options
);
3565 fprintf_unfiltered (gdb_stdlog
,
3566 "linux_nat_wait: [%s], [%s]\n",
3567 target_pid_to_str (ptid
).c_str (),
3568 options_string
.c_str ());
3571 /* Flush the async file first. */
3572 if (target_is_async_p ())
3573 async_file_flush ();
3575 /* Resume LWPs that are currently stopped without any pending status
3576 to report, but are resumed from the core's perspective. LWPs get
3577 in this state if we find them stopping at a time we're not
3578 interested in reporting the event (target_wait on a
3579 specific_process, for example, see linux_nat_wait_1), and
3580 meanwhile the event became uninteresting. Don't bother resuming
3581 LWPs we're not going to wait for if they'd stop immediately. */
3582 if (target_is_non_stop_p ())
3583 iterate_over_lwps (minus_one_ptid
,
3584 [=] (struct lwp_info
*info
)
3586 return resume_stopped_resumed_lwps (info
, ptid
);
3589 event_ptid
= linux_nat_wait_1 (ptid
, ourstatus
, target_options
);
3591 /* If we requested any event, and something came out, assume there
3592 may be more. If we requested a specific lwp or process, also
3593 assume there may be more. */
3594 if (target_is_async_p ()
3595 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3596 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3597 || ptid
!= minus_one_ptid
))
3606 kill_one_lwp (pid_t pid
)
3608 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3611 kill_lwp (pid
, SIGKILL
);
3612 if (debug_linux_nat
)
3614 int save_errno
= errno
;
3616 fprintf_unfiltered (gdb_stdlog
,
3617 "KC: kill (SIGKILL) %ld, 0, 0 (%s)\n", (long) pid
,
3618 save_errno
? safe_strerror (save_errno
) : "OK");
3621 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3624 ptrace (PTRACE_KILL
, pid
, 0, 0);
3625 if (debug_linux_nat
)
3627 int save_errno
= errno
;
3629 fprintf_unfiltered (gdb_stdlog
,
3630 "KC: PTRACE_KILL %ld, 0, 0 (%s)\n", (long) pid
,
3631 save_errno
? safe_strerror (save_errno
) : "OK");
3635 /* Wait for an LWP to die. */
3638 kill_wait_one_lwp (pid_t pid
)
3642 /* We must make sure that there are no pending events (delayed
3643 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3644 program doesn't interfere with any following debugging session. */
3648 res
= my_waitpid (pid
, NULL
, __WALL
);
3649 if (res
!= (pid_t
) -1)
3651 if (debug_linux_nat
)
3652 fprintf_unfiltered (gdb_stdlog
,
3653 "KWC: wait %ld received unknown.\n",
3655 /* The Linux kernel sometimes fails to kill a thread
3656 completely after PTRACE_KILL; that goes from the stop
3657 point in do_fork out to the one in get_signal_to_deliver
3658 and waits again. So kill it again. */
3664 gdb_assert (res
== -1 && errno
== ECHILD
);
3667 /* Callback for iterate_over_lwps. */
3670 kill_callback (struct lwp_info
*lp
)
3672 kill_one_lwp (lp
->ptid
.lwp ());
3676 /* Callback for iterate_over_lwps. */
3679 kill_wait_callback (struct lwp_info
*lp
)
3681 kill_wait_one_lwp (lp
->ptid
.lwp ());
3685 /* Kill the fork children of any threads of inferior INF that are
3686 stopped at a fork event. */
3689 kill_unfollowed_fork_children (struct inferior
*inf
)
3691 for (thread_info
*thread
: inf
->non_exited_threads ())
3693 struct target_waitstatus
*ws
= &thread
->pending_follow
;
3695 if (ws
->kind
== TARGET_WAITKIND_FORKED
3696 || ws
->kind
== TARGET_WAITKIND_VFORKED
)
3698 ptid_t child_ptid
= ws
->value
.related_pid
;
3699 int child_pid
= child_ptid
.pid ();
3700 int child_lwp
= child_ptid
.lwp ();
3702 kill_one_lwp (child_lwp
);
3703 kill_wait_one_lwp (child_lwp
);
3705 /* Let the arch-specific native code know this process is
3707 linux_target
->low_forget_process (child_pid
);
3713 linux_nat_target::kill ()
3715 /* If we're stopped while forking and we haven't followed yet,
3716 kill the other task. We need to do this first because the
3717 parent will be sleeping if this is a vfork. */
3718 kill_unfollowed_fork_children (current_inferior ());
3720 if (forks_exist_p ())
3721 linux_fork_killall ();
3724 ptid_t ptid
= ptid_t (inferior_ptid
.pid ());
3726 /* Stop all threads before killing them, since ptrace requires
3727 that the thread is stopped to sucessfully PTRACE_KILL. */
3728 iterate_over_lwps (ptid
, stop_callback
);
3729 /* ... and wait until all of them have reported back that
3730 they're no longer running. */
3731 iterate_over_lwps (ptid
, stop_wait_callback
);
3733 /* Kill all LWP's ... */
3734 iterate_over_lwps (ptid
, kill_callback
);
3736 /* ... and wait until we've flushed all events. */
3737 iterate_over_lwps (ptid
, kill_wait_callback
);
3740 target_mourn_inferior (inferior_ptid
);
3744 linux_nat_target::mourn_inferior ()
3746 int pid
= inferior_ptid
.pid ();
3748 purge_lwp_list (pid
);
3750 if (! forks_exist_p ())
3751 /* Normal case, no other forks available. */
3752 inf_ptrace_target::mourn_inferior ();
3754 /* Multi-fork case. The current inferior_ptid has exited, but
3755 there are other viable forks to debug. Delete the exiting
3756 one and context-switch to the first available. */
3757 linux_fork_mourn_inferior ();
3759 /* Let the arch-specific native code know this process is gone. */
3760 linux_target
->low_forget_process (pid
);
3763 /* Convert a native/host siginfo object, into/from the siginfo in the
3764 layout of the inferiors' architecture. */
3767 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3769 /* If the low target didn't do anything, then just do a straight
3771 if (!linux_target
->low_siginfo_fixup (siginfo
, inf_siginfo
, direction
))
3774 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3776 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3780 static enum target_xfer_status
3781 linux_xfer_siginfo (enum target_object object
,
3782 const char *annex
, gdb_byte
*readbuf
,
3783 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3784 ULONGEST
*xfered_len
)
3788 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3790 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3791 gdb_assert (readbuf
|| writebuf
);
3793 pid
= inferior_ptid
.lwp ();
3795 pid
= inferior_ptid
.pid ();
3797 if (offset
> sizeof (siginfo
))
3798 return TARGET_XFER_E_IO
;
3801 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3803 return TARGET_XFER_E_IO
;
3805 /* When GDB is built as a 64-bit application, ptrace writes into
3806 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3807 inferior with a 64-bit GDB should look the same as debugging it
3808 with a 32-bit GDB, we need to convert it. GDB core always sees
3809 the converted layout, so any read/write will have to be done
3811 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3813 if (offset
+ len
> sizeof (siginfo
))
3814 len
= sizeof (siginfo
) - offset
;
3816 if (readbuf
!= NULL
)
3817 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3820 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3822 /* Convert back to ptrace layout before flushing it out. */
3823 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3826 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3828 return TARGET_XFER_E_IO
;
3832 return TARGET_XFER_OK
;
3835 static enum target_xfer_status
3836 linux_nat_xfer_osdata (enum target_object object
,
3837 const char *annex
, gdb_byte
*readbuf
,
3838 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3839 ULONGEST
*xfered_len
);
3841 static enum target_xfer_status
3842 linux_proc_xfer_partial (enum target_object object
,
3843 const char *annex
, gdb_byte
*readbuf
,
3844 const gdb_byte
*writebuf
,
3845 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
);
3847 enum target_xfer_status
3848 linux_nat_target::xfer_partial (enum target_object object
,
3849 const char *annex
, gdb_byte
*readbuf
,
3850 const gdb_byte
*writebuf
,
3851 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3853 enum target_xfer_status xfer
;
3855 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3856 return linux_xfer_siginfo (object
, annex
, readbuf
, writebuf
,
3857 offset
, len
, xfered_len
);
3859 /* The target is connected but no live inferior is selected. Pass
3860 this request down to a lower stratum (e.g., the executable
3862 if (object
== TARGET_OBJECT_MEMORY
&& inferior_ptid
== null_ptid
)
3863 return TARGET_XFER_EOF
;
3865 if (object
== TARGET_OBJECT_AUXV
)
3866 return memory_xfer_auxv (this, object
, annex
, readbuf
, writebuf
,
3867 offset
, len
, xfered_len
);
3869 if (object
== TARGET_OBJECT_OSDATA
)
3870 return linux_nat_xfer_osdata (object
, annex
, readbuf
, writebuf
,
3871 offset
, len
, xfered_len
);
3873 /* GDB calculates all addresses in the largest possible address
3875 The address width must be masked before its final use - either by
3876 linux_proc_xfer_partial or inf_ptrace_target::xfer_partial.
3878 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
3880 if (object
== TARGET_OBJECT_MEMORY
)
3882 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
3884 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
3885 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
3888 xfer
= linux_proc_xfer_partial (object
, annex
, readbuf
, writebuf
,
3889 offset
, len
, xfered_len
);
3890 if (xfer
!= TARGET_XFER_EOF
)
3893 return inf_ptrace_target::xfer_partial (object
, annex
, readbuf
, writebuf
,
3894 offset
, len
, xfered_len
);
3898 linux_nat_target::thread_alive (ptid_t ptid
)
3900 /* As long as a PTID is in lwp list, consider it alive. */
3901 return find_lwp_pid (ptid
) != NULL
;
3904 /* Implement the to_update_thread_list target method for this
3908 linux_nat_target::update_thread_list ()
3910 struct lwp_info
*lwp
;
3912 /* We add/delete threads from the list as clone/exit events are
3913 processed, so just try deleting exited threads still in the
3915 delete_exited_threads ();
3917 /* Update the processor core that each lwp/thread was last seen
3921 /* Avoid accessing /proc if the thread hasn't run since we last
3922 time we fetched the thread's core. Accessing /proc becomes
3923 noticeably expensive when we have thousands of LWPs. */
3924 if (lwp
->core
== -1)
3925 lwp
->core
= linux_common_core_of_thread (lwp
->ptid
);
3930 linux_nat_target::pid_to_str (ptid_t ptid
)
3933 && (ptid
.pid () != ptid
.lwp ()
3934 || num_lwps (ptid
.pid ()) > 1))
3935 return string_printf ("LWP %ld", ptid
.lwp ());
3937 return normal_pid_to_str (ptid
);
3941 linux_nat_target::thread_name (struct thread_info
*thr
)
3943 return linux_proc_tid_get_name (thr
->ptid
);
3946 /* Accepts an integer PID; Returns a string representing a file that
3947 can be opened to get the symbols for the child process. */
3950 linux_nat_target::pid_to_exec_file (int pid
)
3952 return linux_proc_pid_to_exec_file (pid
);
3955 /* Implement the to_xfer_partial target method using /proc/<pid>/mem.
3956 Because we can use a single read/write call, this can be much more
3957 efficient than banging away at PTRACE_PEEKTEXT. */
3959 static enum target_xfer_status
3960 linux_proc_xfer_partial (enum target_object object
,
3961 const char *annex
, gdb_byte
*readbuf
,
3962 const gdb_byte
*writebuf
,
3963 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
3969 if (object
!= TARGET_OBJECT_MEMORY
)
3970 return TARGET_XFER_EOF
;
3972 /* Don't bother for one word. */
3973 if (len
< 3 * sizeof (long))
3974 return TARGET_XFER_EOF
;
3976 /* We could keep this file open and cache it - possibly one per
3977 thread. That requires some juggling, but is even faster. */
3978 xsnprintf (filename
, sizeof filename
, "/proc/%ld/mem",
3979 inferior_ptid
.lwp ());
3980 fd
= gdb_open_cloexec (filename
, ((readbuf
? O_RDONLY
: O_WRONLY
)
3983 return TARGET_XFER_EOF
;
3985 /* Use pread64/pwrite64 if available, since they save a syscall and can
3986 handle 64-bit offsets even on 32-bit platforms (for instance, SPARC
3987 debugging a SPARC64 application). */
3989 ret
= (readbuf
? pread64 (fd
, readbuf
, len
, offset
)
3990 : pwrite64 (fd
, writebuf
, len
, offset
));
3992 ret
= lseek (fd
, offset
, SEEK_SET
);
3994 ret
= (readbuf
? read (fd
, readbuf
, len
)
3995 : write (fd
, writebuf
, len
));
4000 if (ret
== -1 || ret
== 0)
4001 return TARGET_XFER_EOF
;
4005 return TARGET_XFER_OK
;
4010 /* Parse LINE as a signal set and add its set bits to SIGS. */
4013 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4015 int len
= strlen (line
) - 1;
4019 if (line
[len
] != '\n')
4020 error (_("Could not parse signal set: %s"), line
);
4028 if (*p
>= '0' && *p
<= '9')
4030 else if (*p
>= 'a' && *p
<= 'f')
4031 digit
= *p
- 'a' + 10;
4033 error (_("Could not parse signal set: %s"), line
);
4038 sigaddset (sigs
, signum
+ 1);
4040 sigaddset (sigs
, signum
+ 2);
4042 sigaddset (sigs
, signum
+ 3);
4044 sigaddset (sigs
, signum
+ 4);
4050 /* Find process PID's pending signals from /proc/pid/status and set
4054 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4055 sigset_t
*blocked
, sigset_t
*ignored
)
4057 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4059 sigemptyset (pending
);
4060 sigemptyset (blocked
);
4061 sigemptyset (ignored
);
4062 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4063 gdb_file_up procfile
= gdb_fopen_cloexec (fname
, "r");
4064 if (procfile
== NULL
)
4065 error (_("Could not open %s"), fname
);
4067 while (fgets (buffer
, PATH_MAX
, procfile
.get ()) != NULL
)
4069 /* Normal queued signals are on the SigPnd line in the status
4070 file. However, 2.6 kernels also have a "shared" pending
4071 queue for delivering signals to a thread group, so check for
4074 Unfortunately some Red Hat kernels include the shared pending
4075 queue but not the ShdPnd status field. */
4077 if (startswith (buffer
, "SigPnd:\t"))
4078 add_line_to_sigset (buffer
+ 8, pending
);
4079 else if (startswith (buffer
, "ShdPnd:\t"))
4080 add_line_to_sigset (buffer
+ 8, pending
);
4081 else if (startswith (buffer
, "SigBlk:\t"))
4082 add_line_to_sigset (buffer
+ 8, blocked
);
4083 else if (startswith (buffer
, "SigIgn:\t"))
4084 add_line_to_sigset (buffer
+ 8, ignored
);
4088 static enum target_xfer_status
4089 linux_nat_xfer_osdata (enum target_object object
,
4090 const char *annex
, gdb_byte
*readbuf
,
4091 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4092 ULONGEST
*xfered_len
)
4094 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4096 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4097 if (*xfered_len
== 0)
4098 return TARGET_XFER_EOF
;
4100 return TARGET_XFER_OK
;
4103 std::vector
<static_tracepoint_marker
>
4104 linux_nat_target::static_tracepoint_markers_by_strid (const char *strid
)
4106 char s
[IPA_CMD_BUF_SIZE
];
4107 int pid
= inferior_ptid
.pid ();
4108 std::vector
<static_tracepoint_marker
> markers
;
4110 ptid_t ptid
= ptid_t (pid
, 0, 0);
4111 static_tracepoint_marker marker
;
4116 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4117 s
[sizeof ("qTfSTM")] = 0;
4119 agent_run_command (pid
, s
, strlen (s
) + 1);
4122 SCOPE_EXIT
{ target_continue_no_signal (ptid
); };
4128 parse_static_tracepoint_marker_definition (p
, &p
, &marker
);
4130 if (strid
== NULL
|| marker
.str_id
== strid
)
4131 markers
.push_back (std::move (marker
));
4133 while (*p
++ == ','); /* comma-separated list */
4135 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4136 s
[sizeof ("qTsSTM")] = 0;
4137 agent_run_command (pid
, s
, strlen (s
) + 1);
4144 /* target_is_async_p implementation. */
4147 linux_nat_target::is_async_p ()
4149 return linux_is_async_p ();
4152 /* target_can_async_p implementation. */
4155 linux_nat_target::can_async_p ()
4157 /* We're always async, unless the user explicitly prevented it with the
4158 "maint set target-async" command. */
4159 return target_async_permitted
;
4163 linux_nat_target::supports_non_stop ()
4168 /* to_always_non_stop_p implementation. */
4171 linux_nat_target::always_non_stop_p ()
4176 /* True if we want to support multi-process. To be removed when GDB
4177 supports multi-exec. */
4179 int linux_multi_process
= 1;
4182 linux_nat_target::supports_multi_process ()
4184 return linux_multi_process
;
4188 linux_nat_target::supports_disable_randomization ()
4190 #ifdef HAVE_PERSONALITY
4197 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4198 so we notice when any child changes state, and notify the
4199 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4200 above to wait for the arrival of a SIGCHLD. */
4203 sigchld_handler (int signo
)
4205 int old_errno
= errno
;
4207 if (debug_linux_nat
)
4208 ui_file_write_async_safe (gdb_stdlog
,
4209 "sigchld\n", sizeof ("sigchld\n") - 1);
4211 if (signo
== SIGCHLD
4212 && linux_nat_event_pipe
[0] != -1)
4213 async_file_mark (); /* Let the event loop know that there are
4214 events to handle. */
4219 /* Callback registered with the target events file descriptor. */
4222 handle_target_event (int error
, gdb_client_data client_data
)
4224 inferior_event_handler (INF_REG_EVENT
, NULL
);
4227 /* Create/destroy the target events pipe. Returns previous state. */
4230 linux_async_pipe (int enable
)
4232 int previous
= linux_is_async_p ();
4234 if (previous
!= enable
)
4238 /* Block child signals while we create/destroy the pipe, as
4239 their handler writes to it. */
4240 block_child_signals (&prev_mask
);
4244 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4245 internal_error (__FILE__
, __LINE__
,
4246 "creating event pipe failed.");
4248 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4249 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4253 close (linux_nat_event_pipe
[0]);
4254 close (linux_nat_event_pipe
[1]);
4255 linux_nat_event_pipe
[0] = -1;
4256 linux_nat_event_pipe
[1] = -1;
4259 restore_child_signals_mask (&prev_mask
);
4265 /* target_async implementation. */
4268 linux_nat_target::async (int enable
)
4272 if (!linux_async_pipe (1))
4274 add_file_handler (linux_nat_event_pipe
[0],
4275 handle_target_event
, NULL
);
4276 /* There may be pending events to handle. Tell the event loop
4283 delete_file_handler (linux_nat_event_pipe
[0]);
4284 linux_async_pipe (0);
4289 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4293 linux_nat_stop_lwp (struct lwp_info
*lwp
)
4297 if (debug_linux_nat
)
4298 fprintf_unfiltered (gdb_stdlog
,
4299 "LNSL: running -> suspending %s\n",
4300 target_pid_to_str (lwp
->ptid
).c_str ());
4303 if (lwp
->last_resume_kind
== resume_stop
)
4305 if (debug_linux_nat
)
4306 fprintf_unfiltered (gdb_stdlog
,
4307 "linux-nat: already stopping LWP %ld at "
4313 stop_callback (lwp
);
4314 lwp
->last_resume_kind
= resume_stop
;
4318 /* Already known to be stopped; do nothing. */
4320 if (debug_linux_nat
)
4322 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4323 fprintf_unfiltered (gdb_stdlog
,
4324 "LNSL: already stopped/stop_requested %s\n",
4325 target_pid_to_str (lwp
->ptid
).c_str ());
4327 fprintf_unfiltered (gdb_stdlog
,
4328 "LNSL: already stopped/no "
4329 "stop_requested yet %s\n",
4330 target_pid_to_str (lwp
->ptid
).c_str ());
4337 linux_nat_target::stop (ptid_t ptid
)
4339 iterate_over_lwps (ptid
, linux_nat_stop_lwp
);
4343 linux_nat_target::close ()
4345 /* Unregister from the event loop. */
4349 inf_ptrace_target::close ();
4352 /* When requests are passed down from the linux-nat layer to the
4353 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4354 used. The address space pointer is stored in the inferior object,
4355 but the common code that is passed such ptid can't tell whether
4356 lwpid is a "main" process id or not (it assumes so). We reverse
4357 look up the "main" process id from the lwp here. */
4359 struct address_space
*
4360 linux_nat_target::thread_address_space (ptid_t ptid
)
4362 struct lwp_info
*lwp
;
4363 struct inferior
*inf
;
4366 if (ptid
.lwp () == 0)
4368 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4370 lwp
= find_lwp_pid (ptid
);
4371 pid
= lwp
->ptid
.pid ();
4375 /* A (pid,lwpid,0) ptid. */
4379 inf
= find_inferior_pid (pid
);
4380 gdb_assert (inf
!= NULL
);
4384 /* Return the cached value of the processor core for thread PTID. */
4387 linux_nat_target::core_of_thread (ptid_t ptid
)
4389 struct lwp_info
*info
= find_lwp_pid (ptid
);
4396 /* Implementation of to_filesystem_is_local. */
4399 linux_nat_target::filesystem_is_local ()
4401 struct inferior
*inf
= current_inferior ();
4403 if (inf
->fake_pid_p
|| inf
->pid
== 0)
4406 return linux_ns_same (inf
->pid
, LINUX_NS_MNT
);
4409 /* Convert the INF argument passed to a to_fileio_* method
4410 to a process ID suitable for passing to its corresponding
4411 linux_mntns_* function. If INF is non-NULL then the
4412 caller is requesting the filesystem seen by INF. If INF
4413 is NULL then the caller is requesting the filesystem seen
4414 by the GDB. We fall back to GDB's filesystem in the case
4415 that INF is non-NULL but its PID is unknown. */
4418 linux_nat_fileio_pid_of (struct inferior
*inf
)
4420 if (inf
== NULL
|| inf
->fake_pid_p
|| inf
->pid
== 0)
4426 /* Implementation of to_fileio_open. */
4429 linux_nat_target::fileio_open (struct inferior
*inf
, const char *filename
,
4430 int flags
, int mode
, int warn_if_slow
,
4437 if (fileio_to_host_openflags (flags
, &nat_flags
) == -1
4438 || fileio_to_host_mode (mode
, &nat_mode
) == -1)
4440 *target_errno
= FILEIO_EINVAL
;
4444 fd
= linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf
),
4445 filename
, nat_flags
, nat_mode
);
4447 *target_errno
= host_to_fileio_error (errno
);
4452 /* Implementation of to_fileio_readlink. */
4454 gdb::optional
<std::string
>
4455 linux_nat_target::fileio_readlink (struct inferior
*inf
, const char *filename
,
4461 len
= linux_mntns_readlink (linux_nat_fileio_pid_of (inf
),
4462 filename
, buf
, sizeof (buf
));
4465 *target_errno
= host_to_fileio_error (errno
);
4469 return std::string (buf
, len
);
4472 /* Implementation of to_fileio_unlink. */
4475 linux_nat_target::fileio_unlink (struct inferior
*inf
, const char *filename
,
4480 ret
= linux_mntns_unlink (linux_nat_fileio_pid_of (inf
),
4483 *target_errno
= host_to_fileio_error (errno
);
4488 /* Implementation of the to_thread_events method. */
4491 linux_nat_target::thread_events (int enable
)
4493 report_thread_events
= enable
;
4496 linux_nat_target::linux_nat_target ()
4498 /* We don't change the stratum; this target will sit at
4499 process_stratum and thread_db will set at thread_stratum. This
4500 is a little strange, since this is a multi-threaded-capable
4501 target, but we want to be on the stack below thread_db, and we
4502 also want to be used for single-threaded processes. */
4505 /* See linux-nat.h. */
4508 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4517 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4520 memset (siginfo
, 0, sizeof (*siginfo
));
4526 /* See nat/linux-nat.h. */
4529 current_lwp_ptid (void)
4531 gdb_assert (inferior_ptid
.lwp_p ());
4532 return inferior_ptid
;
4536 _initialize_linux_nat (void)
4538 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4539 &debug_linux_nat
, _("\
4540 Set debugging of GNU/Linux lwp module."), _("\
4541 Show debugging of GNU/Linux lwp module."), _("\
4542 Enables printf debugging output."),
4544 show_debug_linux_nat
,
4545 &setdebuglist
, &showdebuglist
);
4547 add_setshow_boolean_cmd ("linux-namespaces", class_maintenance
,
4548 &debug_linux_namespaces
, _("\
4549 Set debugging of GNU/Linux namespaces module."), _("\
4550 Show debugging of GNU/Linux namespaces module."), _("\
4551 Enables printf debugging output."),
4554 &setdebuglist
, &showdebuglist
);
4556 /* Install a SIGCHLD handler. */
4557 sigchld_action
.sa_handler
= sigchld_handler
;
4558 sigemptyset (&sigchld_action
.sa_mask
);
4559 sigchld_action
.sa_flags
= SA_RESTART
;
4561 /* Make it the default. */
4562 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4564 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4565 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4566 sigdelset (&suspend_mask
, SIGCHLD
);
4568 sigemptyset (&blocked_mask
);
4570 lwp_lwpid_htab_create ();
4572 /* Set the proper function to generate a message when ptrace
4574 inf_ptrace_me_fail_reason
= linux_ptrace_me_fail_reason
;
4578 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4579 the GNU/Linux Threads library and therefore doesn't really belong
4582 /* Return the set of signals used by the threads library in *SET. */
4585 lin_thread_get_thread_signals (sigset_t
*set
)
4589 /* NPTL reserves the first two RT signals, but does not provide any
4590 way for the debugger to query the signal numbers - fortunately
4591 they don't change. */
4592 sigaddset (set
, __SIGRTMIN
);
4593 sigaddset (set
, __SIGRTMIN
+ 1);