1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2021 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 "gdbsupport/event-loop.h"
51 #include "event-top.h"
53 #include <sys/types.h>
55 #include "xml-support.h"
58 #include "nat/linux-osdata.h"
59 #include "linux-tdep.h"
61 #include "gdbsupport/agent.h"
62 #include "tracepoint.h"
63 #include "gdbsupport/buffer.h"
64 #include "target-descriptions.h"
65 #include "gdbsupport/filestuff.h"
67 #include "nat/linux-namespaces.h"
68 #include "gdbsupport/fileio.h"
69 #include "gdbsupport/scope-exit.h"
70 #include "gdbsupport/gdb-sigmask.h"
71 #include "gdbsupport/common-debug.h"
73 /* This comment documents high-level logic of this file.
75 Waiting for events in sync mode
76 ===============================
78 When waiting for an event in a specific thread, we just use waitpid,
79 passing the specific pid, and not passing WNOHANG.
81 When waiting for an event in all threads, waitpid is not quite good:
83 - If the thread group leader exits while other threads in the thread
84 group still exist, waitpid(TGID, ...) hangs. That waitpid won't
85 return an exit status until the other threads in the group are
88 - When a non-leader thread execs, that thread just vanishes without
89 reporting an exit (so we'd hang if we waited for it explicitly in
90 that case). The exec event is instead reported to the TGID pid.
92 The solution is to always use -1 and WNOHANG, together with
95 First, we use non-blocking waitpid to check for events. If nothing is
96 found, we use sigsuspend to wait for SIGCHLD. When SIGCHLD arrives,
97 it means something happened to a child process. As soon as we know
98 there's an event, we get back to calling nonblocking waitpid.
100 Note that SIGCHLD should be blocked between waitpid and sigsuspend
101 calls, so that we don't miss a signal. If SIGCHLD arrives in between,
102 when it's blocked, the signal becomes pending and sigsuspend
103 immediately notices it and returns.
105 Waiting for events in async mode (TARGET_WNOHANG)
106 =================================================
108 In async mode, GDB should always be ready to handle both user input
109 and target events, so neither blocking waitpid nor sigsuspend are
110 viable options. Instead, we should asynchronously notify the GDB main
111 event loop whenever there's an unprocessed event from the target. We
112 detect asynchronous target events by handling SIGCHLD signals. To
113 notify the event loop about target events, the self-pipe trick is used
114 --- a pipe is registered as waitable event source in the event loop,
115 the event loop select/poll's on the read end of this pipe (as well on
116 other event sources, e.g., stdin), and the SIGCHLD handler writes a
117 byte to this pipe. This is more portable than relying on
118 pselect/ppoll, since on kernels that lack those syscalls, libc
119 emulates them with select/poll+sigprocmask, and that is racy
120 (a.k.a. plain broken).
122 Obviously, if we fail to notify the event loop if there's a target
123 event, it's bad. OTOH, if we notify the event loop when there's no
124 event from the target, linux_nat_wait will detect that there's no real
125 event to report, and return event of type TARGET_WAITKIND_IGNORE.
126 This is mostly harmless, but it will waste time and is better avoided.
128 The main design point is that every time GDB is outside linux-nat.c,
129 we have a SIGCHLD handler installed that is called when something
130 happens to the target and notifies the GDB event loop. Whenever GDB
131 core decides to handle the event, and calls into linux-nat.c, we
132 process things as in sync mode, except that the we never block in
135 While processing an event, we may end up momentarily blocked in
136 waitpid calls. Those waitpid calls, while blocking, are guarantied to
137 return quickly. E.g., in all-stop mode, before reporting to the core
138 that an LWP hit a breakpoint, all LWPs are stopped by sending them
139 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
140 Note that this is different from blocking indefinitely waiting for the
141 next event --- here, we're already handling an event.
146 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
147 signal is not entirely significant; we just need for a signal to be delivered,
148 so that we can intercept it. SIGSTOP's advantage is that it can not be
149 blocked. A disadvantage is that it is not a real-time signal, so it can only
150 be queued once; we do not keep track of other sources of SIGSTOP.
152 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
153 use them, because they have special behavior when the signal is generated -
154 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
155 kills the entire thread group.
157 A delivered SIGSTOP would stop the entire thread group, not just the thread we
158 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
159 cancel it (by PTRACE_CONT without passing SIGSTOP).
161 We could use a real-time signal instead. This would solve those problems; we
162 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
163 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
164 generates it, and there are races with trying to find a signal that is not
170 The case of a thread group (process) with 3 or more threads, and a
171 thread other than the leader execs is worth detailing:
173 On an exec, the Linux kernel destroys all threads except the execing
174 one in the thread group, and resets the execing thread's tid to the
175 tgid. No exit notification is sent for the execing thread -- from the
176 ptracer's perspective, it appears as though the execing thread just
177 vanishes. Until we reap all other threads except the leader and the
178 execing thread, the leader will be zombie, and the execing thread will
179 be in `D (disc sleep)' state. As soon as all other threads are
180 reaped, the execing thread changes its tid to the tgid, and the
181 previous (zombie) leader vanishes, giving place to the "new"
185 #define O_LARGEFILE 0
188 struct linux_nat_target
*linux_target
;
190 /* Does the current host support PTRACE_GETREGSET? */
191 enum tribool have_ptrace_getregset
= TRIBOOL_UNKNOWN
;
193 static unsigned int debug_linux_nat
;
195 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
196 struct cmd_list_element
*c
, const char *value
)
198 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
202 /* Print a linux-nat debug statement. */
204 #define linux_nat_debug_printf(fmt, ...) \
205 debug_prefixed_printf_cond (debug_linux_nat, "linux-nat", fmt, ##__VA_ARGS__)
207 struct simple_pid_list
211 struct simple_pid_list
*next
;
213 static struct simple_pid_list
*stopped_pids
;
215 /* Whether target_thread_events is in effect. */
216 static int report_thread_events
;
218 /* Async mode support. */
220 /* The read/write ends of the pipe registered as waitable file in the
222 static int linux_nat_event_pipe
[2] = { -1, -1 };
224 /* True if we're currently in async mode. */
225 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
227 /* Flush the event pipe. */
230 async_file_flush (void)
237 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
239 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
242 /* Put something (anything, doesn't matter what, or how much) in event
243 pipe, so that the select/poll in the event-loop realizes we have
244 something to process. */
247 async_file_mark (void)
251 /* It doesn't really matter what the pipe contains, as long we end
252 up with something in it. Might as well flush the previous
258 ret
= write (linux_nat_event_pipe
[1], "+", 1);
260 while (ret
== -1 && errno
== EINTR
);
262 /* Ignore EAGAIN. If the pipe is full, the event loop will already
263 be awakened anyway. */
266 static int kill_lwp (int lwpid
, int signo
);
268 static int stop_callback (struct lwp_info
*lp
);
270 static void block_child_signals (sigset_t
*prev_mask
);
271 static void restore_child_signals_mask (sigset_t
*prev_mask
);
274 static struct lwp_info
*add_lwp (ptid_t ptid
);
275 static void purge_lwp_list (int pid
);
276 static void delete_lwp (ptid_t ptid
);
277 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
279 static int lwp_status_pending_p (struct lwp_info
*lp
);
281 static void save_stop_reason (struct lwp_info
*lp
);
286 /* See nat/linux-nat.h. */
289 ptid_of_lwp (struct lwp_info
*lwp
)
294 /* See nat/linux-nat.h. */
297 lwp_set_arch_private_info (struct lwp_info
*lwp
,
298 struct arch_lwp_info
*info
)
300 lwp
->arch_private
= info
;
303 /* See nat/linux-nat.h. */
305 struct arch_lwp_info
*
306 lwp_arch_private_info (struct lwp_info
*lwp
)
308 return lwp
->arch_private
;
311 /* See nat/linux-nat.h. */
314 lwp_is_stopped (struct lwp_info
*lwp
)
319 /* See nat/linux-nat.h. */
321 enum target_stop_reason
322 lwp_stop_reason (struct lwp_info
*lwp
)
324 return lwp
->stop_reason
;
327 /* See nat/linux-nat.h. */
330 lwp_is_stepping (struct lwp_info
*lwp
)
336 /* Trivial list manipulation functions to keep track of a list of
337 new stopped processes. */
339 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
341 struct simple_pid_list
*new_pid
= XNEW (struct simple_pid_list
);
344 new_pid
->status
= status
;
345 new_pid
->next
= *listp
;
350 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
352 struct simple_pid_list
**p
;
354 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
355 if ((*p
)->pid
== pid
)
357 struct simple_pid_list
*next
= (*p
)->next
;
359 *statusp
= (*p
)->status
;
367 /* Return the ptrace options that we want to try to enable. */
370 linux_nat_ptrace_options (int attached
)
375 options
|= PTRACE_O_EXITKILL
;
377 options
|= (PTRACE_O_TRACESYSGOOD
378 | PTRACE_O_TRACEVFORKDONE
379 | PTRACE_O_TRACEVFORK
381 | PTRACE_O_TRACEEXEC
);
386 /* Initialize ptrace and procfs warnings and check for supported
387 ptrace features given PID.
389 ATTACHED should be nonzero iff we attached to the inferior. */
392 linux_init_ptrace_procfs (pid_t pid
, int attached
)
394 int options
= linux_nat_ptrace_options (attached
);
396 linux_enable_event_reporting (pid
, options
);
397 linux_ptrace_init_warnings ();
398 linux_proc_init_warnings ();
401 linux_nat_target::~linux_nat_target ()
405 linux_nat_target::post_attach (int pid
)
407 linux_init_ptrace_procfs (pid
, 1);
411 linux_nat_target::post_startup_inferior (ptid_t ptid
)
413 linux_init_ptrace_procfs (ptid
.pid (), 0);
416 /* Return the number of known LWPs in the tgid given by PID. */
424 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
425 if (lp
->ptid
.pid () == pid
)
431 /* Deleter for lwp_info unique_ptr specialisation. */
435 void operator() (struct lwp_info
*lwp
) const
437 delete_lwp (lwp
->ptid
);
441 /* A unique_ptr specialisation for lwp_info. */
443 typedef std::unique_ptr
<struct lwp_info
, lwp_deleter
> lwp_info_up
;
445 /* Target hook for follow_fork. On entry inferior_ptid must be the
446 ptid of the followed inferior. At return, inferior_ptid will be
450 linux_nat_target::follow_fork (bool follow_child
, bool detach_fork
)
454 struct lwp_info
*child_lp
= NULL
;
456 ptid_t parent_ptid
, child_ptid
;
457 int parent_pid
, child_pid
;
459 has_vforked
= (inferior_thread ()->pending_follow
.kind
460 == TARGET_WAITKIND_VFORKED
);
461 parent_ptid
= inferior_ptid
;
462 child_ptid
= inferior_thread ()->pending_follow
.value
.related_pid
;
463 parent_pid
= parent_ptid
.lwp ();
464 child_pid
= child_ptid
.lwp ();
466 /* We're already attached to the parent, by default. */
467 child_lp
= add_lwp (child_ptid
);
468 child_lp
->stopped
= 1;
469 child_lp
->last_resume_kind
= resume_stop
;
471 /* Detach new forked process? */
474 int child_stop_signal
= 0;
475 bool detach_child
= true;
477 /* Move CHILD_LP into a unique_ptr and clear the source pointer
478 to prevent us doing anything stupid with it. */
479 lwp_info_up
child_lp_ptr (child_lp
);
482 linux_target
->low_prepare_to_resume (child_lp_ptr
.get ());
484 /* When debugging an inferior in an architecture that supports
485 hardware single stepping on a kernel without commit
486 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
487 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
488 set if the parent process had them set.
489 To work around this, single step the child process
490 once before detaching to clear the flags. */
492 /* Note that we consult the parent's architecture instead of
493 the child's because there's no inferior for the child at
495 if (!gdbarch_software_single_step_p (target_thread_architecture
500 linux_disable_event_reporting (child_pid
);
501 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
502 perror_with_name (_("Couldn't do single step"));
503 if (my_waitpid (child_pid
, &status
, 0) < 0)
504 perror_with_name (_("Couldn't wait vfork process"));
507 detach_child
= WIFSTOPPED (status
);
508 child_stop_signal
= WSTOPSIG (status
);
514 int signo
= child_stop_signal
;
517 && !signal_pass_state (gdb_signal_from_host (signo
)))
519 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
524 /* Switching inferior_ptid is not enough, because then
525 inferior_thread () would crash by not finding the thread
526 in the current inferior. */
527 scoped_restore_current_thread restore_current_thread
;
528 thread_info
*child
= find_thread_ptid (this, child_ptid
);
529 switch_to_thread (child
);
531 /* Let the thread_db layer learn about this new process. */
532 check_for_thread_db ();
537 struct lwp_info
*parent_lp
;
539 parent_lp
= find_lwp_pid (parent_ptid
);
540 gdb_assert (linux_supports_tracefork () >= 0);
542 if (linux_supports_tracevforkdone ())
544 linux_nat_debug_printf ("waiting for VFORK_DONE on %d",
546 parent_lp
->stopped
= 1;
548 /* We'll handle the VFORK_DONE event like any other
549 event, in target_wait. */
553 /* We can't insert breakpoints until the child has
554 finished with the shared memory region. We need to
555 wait until that happens. Ideal would be to just
557 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
558 - waitpid (parent_pid, &status, __WALL);
559 However, most architectures can't handle a syscall
560 being traced on the way out if it wasn't traced on
563 We might also think to loop, continuing the child
564 until it exits or gets a SIGTRAP. One problem is
565 that the child might call ptrace with PTRACE_TRACEME.
567 There's no simple and reliable way to figure out when
568 the vforked child will be done with its copy of the
569 shared memory. We could step it out of the syscall,
570 two instructions, let it go, and then single-step the
571 parent once. When we have hardware single-step, this
572 would work; with software single-step it could still
573 be made to work but we'd have to be able to insert
574 single-step breakpoints in the child, and we'd have
575 to insert -just- the single-step breakpoint in the
576 parent. Very awkward.
578 In the end, the best we can do is to make sure it
579 runs for a little while. Hopefully it will be out of
580 range of any breakpoints we reinsert. Usually this
581 is only the single-step breakpoint at vfork's return
584 linux_nat_debug_printf ("no VFORK_DONE support, sleeping a bit");
588 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
589 and leave it pending. The next linux_nat_resume call
590 will notice a pending event, and bypasses actually
591 resuming the inferior. */
592 parent_lp
->status
= 0;
593 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
594 parent_lp
->stopped
= 1;
596 /* If we're in async mode, need to tell the event loop
597 there's something here to process. */
598 if (target_is_async_p ())
605 struct lwp_info
*child_lp
;
607 child_lp
= add_lwp (inferior_ptid
);
608 child_lp
->stopped
= 1;
609 child_lp
->last_resume_kind
= resume_stop
;
611 /* Let the thread_db layer learn about this new process. */
612 check_for_thread_db ();
620 linux_nat_target::insert_fork_catchpoint (int pid
)
622 return !linux_supports_tracefork ();
626 linux_nat_target::remove_fork_catchpoint (int pid
)
632 linux_nat_target::insert_vfork_catchpoint (int pid
)
634 return !linux_supports_tracefork ();
638 linux_nat_target::remove_vfork_catchpoint (int pid
)
644 linux_nat_target::insert_exec_catchpoint (int pid
)
646 return !linux_supports_tracefork ();
650 linux_nat_target::remove_exec_catchpoint (int pid
)
656 linux_nat_target::set_syscall_catchpoint (int pid
, bool needed
, int any_count
,
657 gdb::array_view
<const int> syscall_counts
)
659 if (!linux_supports_tracesysgood ())
662 /* On GNU/Linux, we ignore the arguments. It means that we only
663 enable the syscall catchpoints, but do not disable them.
665 Also, we do not use the `syscall_counts' information because we do not
666 filter system calls here. We let GDB do the logic for us. */
670 /* List of known LWPs, keyed by LWP PID. This speeds up the common
671 case of mapping a PID returned from the kernel to our corresponding
672 lwp_info data structure. */
673 static htab_t lwp_lwpid_htab
;
675 /* Calculate a hash from a lwp_info's LWP PID. */
678 lwp_info_hash (const void *ap
)
680 const struct lwp_info
*lp
= (struct lwp_info
*) ap
;
681 pid_t pid
= lp
->ptid
.lwp ();
683 return iterative_hash_object (pid
, 0);
686 /* Equality function for the lwp_info hash table. Compares the LWP's
690 lwp_lwpid_htab_eq (const void *a
, const void *b
)
692 const struct lwp_info
*entry
= (const struct lwp_info
*) a
;
693 const struct lwp_info
*element
= (const struct lwp_info
*) b
;
695 return entry
->ptid
.lwp () == element
->ptid
.lwp ();
698 /* Create the lwp_lwpid_htab hash table. */
701 lwp_lwpid_htab_create (void)
703 lwp_lwpid_htab
= htab_create (100, lwp_info_hash
, lwp_lwpid_htab_eq
, NULL
);
706 /* Add LP to the hash table. */
709 lwp_lwpid_htab_add_lwp (struct lwp_info
*lp
)
713 slot
= htab_find_slot (lwp_lwpid_htab
, lp
, INSERT
);
714 gdb_assert (slot
!= NULL
&& *slot
== NULL
);
718 /* Head of doubly-linked list of known LWPs. Sorted by reverse
719 creation order. This order is assumed in some cases. E.g.,
720 reaping status after killing alls lwps of a process: the leader LWP
721 must be reaped last. */
722 struct lwp_info
*lwp_list
;
724 /* Add LP to sorted-by-reverse-creation-order doubly-linked list. */
727 lwp_list_add (struct lwp_info
*lp
)
730 if (lwp_list
!= NULL
)
735 /* Remove LP from sorted-by-reverse-creation-order doubly-linked
739 lwp_list_remove (struct lwp_info
*lp
)
741 /* Remove from sorted-by-creation-order list. */
742 if (lp
->next
!= NULL
)
743 lp
->next
->prev
= lp
->prev
;
744 if (lp
->prev
!= NULL
)
745 lp
->prev
->next
= lp
->next
;
752 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
753 _initialize_linux_nat. */
754 static sigset_t suspend_mask
;
756 /* Signals to block to make that sigsuspend work. */
757 static sigset_t blocked_mask
;
759 /* SIGCHLD action. */
760 static struct sigaction sigchld_action
;
762 /* Block child signals (SIGCHLD and linux threads signals), and store
763 the previous mask in PREV_MASK. */
766 block_child_signals (sigset_t
*prev_mask
)
768 /* Make sure SIGCHLD is blocked. */
769 if (!sigismember (&blocked_mask
, SIGCHLD
))
770 sigaddset (&blocked_mask
, SIGCHLD
);
772 gdb_sigmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
775 /* Restore child signals mask, previously returned by
776 block_child_signals. */
779 restore_child_signals_mask (sigset_t
*prev_mask
)
781 gdb_sigmask (SIG_SETMASK
, prev_mask
, NULL
);
784 /* Mask of signals to pass directly to the inferior. */
785 static sigset_t pass_mask
;
787 /* Update signals to pass to the inferior. */
789 linux_nat_target::pass_signals
790 (gdb::array_view
<const unsigned char> pass_signals
)
794 sigemptyset (&pass_mask
);
796 for (signo
= 1; signo
< NSIG
; signo
++)
798 int target_signo
= gdb_signal_from_host (signo
);
799 if (target_signo
< pass_signals
.size () && pass_signals
[target_signo
])
800 sigaddset (&pass_mask
, signo
);
806 /* Prototypes for local functions. */
807 static int stop_wait_callback (struct lwp_info
*lp
);
808 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, const ptid_t wait_ptid
);
809 static int check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
);
813 /* Destroy and free LP. */
816 lwp_free (struct lwp_info
*lp
)
818 /* Let the arch specific bits release arch_lwp_info. */
819 linux_target
->low_delete_thread (lp
->arch_private
);
824 /* Traversal function for purge_lwp_list. */
827 lwp_lwpid_htab_remove_pid (void **slot
, void *info
)
829 struct lwp_info
*lp
= (struct lwp_info
*) *slot
;
830 int pid
= *(int *) info
;
832 if (lp
->ptid
.pid () == pid
)
834 htab_clear_slot (lwp_lwpid_htab
, slot
);
835 lwp_list_remove (lp
);
842 /* Remove all LWPs belong to PID from the lwp list. */
845 purge_lwp_list (int pid
)
847 htab_traverse_noresize (lwp_lwpid_htab
, lwp_lwpid_htab_remove_pid
, &pid
);
850 /* Add the LWP specified by PTID to the list. PTID is the first LWP
851 in the process. Return a pointer to the structure describing the
854 This differs from add_lwp in that we don't let the arch specific
855 bits know about this new thread. Current clients of this callback
856 take the opportunity to install watchpoints in the new thread, and
857 we shouldn't do that for the first thread. If we're spawning a
858 child ("run"), the thread executes the shell wrapper first, and we
859 shouldn't touch it until it execs the program we want to debug.
860 For "attach", it'd be okay to call the callback, but it's not
861 necessary, because watchpoints can't yet have been inserted into
864 static struct lwp_info
*
865 add_initial_lwp (ptid_t ptid
)
869 gdb_assert (ptid
.lwp_p ());
871 lp
= XNEW (struct lwp_info
);
873 memset (lp
, 0, sizeof (struct lwp_info
));
875 lp
->last_resume_kind
= resume_continue
;
876 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
881 /* Add to sorted-by-reverse-creation-order list. */
884 /* Add to keyed-by-pid htab. */
885 lwp_lwpid_htab_add_lwp (lp
);
890 /* Add the LWP specified by PID to the list. Return a pointer to the
891 structure describing the new LWP. The LWP should already be
894 static struct lwp_info
*
895 add_lwp (ptid_t ptid
)
899 lp
= add_initial_lwp (ptid
);
901 /* Let the arch specific bits know about this new thread. Current
902 clients of this callback take the opportunity to install
903 watchpoints in the new thread. We don't do this for the first
904 thread though. See add_initial_lwp. */
905 linux_target
->low_new_thread (lp
);
910 /* Remove the LWP specified by PID from the list. */
913 delete_lwp (ptid_t ptid
)
917 struct lwp_info dummy
;
920 slot
= htab_find_slot (lwp_lwpid_htab
, &dummy
, NO_INSERT
);
924 lp
= *(struct lwp_info
**) slot
;
925 gdb_assert (lp
!= NULL
);
927 htab_clear_slot (lwp_lwpid_htab
, slot
);
929 /* Remove from sorted-by-creation-order list. */
930 lwp_list_remove (lp
);
936 /* Return a pointer to the structure describing the LWP corresponding
937 to PID. If no corresponding LWP could be found, return NULL. */
939 static struct lwp_info
*
940 find_lwp_pid (ptid_t ptid
)
944 struct lwp_info dummy
;
951 dummy
.ptid
= ptid_t (0, lwp
, 0);
952 lp
= (struct lwp_info
*) htab_find (lwp_lwpid_htab
, &dummy
);
956 /* See nat/linux-nat.h. */
959 iterate_over_lwps (ptid_t filter
,
960 gdb::function_view
<iterate_over_lwps_ftype
> callback
)
962 struct lwp_info
*lp
, *lpnext
;
964 for (lp
= lwp_list
; lp
; lp
= lpnext
)
968 if (lp
->ptid
.matches (filter
))
970 if (callback (lp
) != 0)
978 /* Update our internal state when changing from one checkpoint to
979 another indicated by NEW_PTID. We can only switch single-threaded
980 applications, so we only create one new LWP, and the previous list
984 linux_nat_switch_fork (ptid_t new_ptid
)
988 purge_lwp_list (inferior_ptid
.pid ());
990 lp
= add_lwp (new_ptid
);
993 /* This changes the thread's ptid while preserving the gdb thread
994 num. Also changes the inferior pid, while preserving the
996 thread_change_ptid (linux_target
, inferior_ptid
, new_ptid
);
998 /* We've just told GDB core that the thread changed target id, but,
999 in fact, it really is a different thread, with different register
1001 registers_changed ();
1004 /* Handle the exit of a single thread LP. */
1007 exit_lwp (struct lwp_info
*lp
)
1009 struct thread_info
*th
= find_thread_ptid (linux_target
, lp
->ptid
);
1013 if (print_thread_events
)
1014 printf_unfiltered (_("[%s exited]\n"),
1015 target_pid_to_str (lp
->ptid
).c_str ());
1020 delete_lwp (lp
->ptid
);
1023 /* Wait for the LWP specified by LP, which we have just attached to.
1024 Returns a wait status for that LWP, to cache. */
1027 linux_nat_post_attach_wait (ptid_t ptid
, int *signalled
)
1029 pid_t new_pid
, pid
= ptid
.lwp ();
1032 if (linux_proc_pid_is_stopped (pid
))
1034 linux_nat_debug_printf ("Attaching to a stopped process");
1036 /* The process is definitely stopped. It is in a job control
1037 stop, unless the kernel predates the TASK_STOPPED /
1038 TASK_TRACED distinction, in which case it might be in a
1039 ptrace stop. Make sure it is in a ptrace stop; from there we
1040 can kill it, signal it, et cetera.
1042 First make sure there is a pending SIGSTOP. Since we are
1043 already attached, the process can not transition from stopped
1044 to running without a PTRACE_CONT; so we know this signal will
1045 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1046 probably already in the queue (unless this kernel is old
1047 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1048 is not an RT signal, it can only be queued once. */
1049 kill_lwp (pid
, SIGSTOP
);
1051 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1052 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1053 ptrace (PTRACE_CONT
, pid
, 0, 0);
1056 /* Make sure the initial process is stopped. The user-level threads
1057 layer might want to poke around in the inferior, and that won't
1058 work if things haven't stabilized yet. */
1059 new_pid
= my_waitpid (pid
, &status
, __WALL
);
1060 gdb_assert (pid
== new_pid
);
1062 if (!WIFSTOPPED (status
))
1064 /* The pid we tried to attach has apparently just exited. */
1065 linux_nat_debug_printf ("Failed to stop %d: %s", pid
,
1066 status_to_str (status
));
1070 if (WSTOPSIG (status
) != SIGSTOP
)
1073 linux_nat_debug_printf ("Received %s after attaching",
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 linux_nat_debug_printf
1125 ("Cannot attach to lwp %d: thread is gone (%d: %s)",
1126 lwpid
, err
, safe_strerror (err
));
1132 = linux_ptrace_attach_fail_reason_string (ptid
, err
);
1134 warning (_("Cannot attach to lwp %d: %s"),
1135 lwpid
, reason
.c_str ());
1140 linux_nat_debug_printf ("PTRACE_ATTACH %s, 0, 0 (OK)",
1141 target_pid_to_str (ptid
).c_str ());
1143 lp
= add_lwp (ptid
);
1145 /* The next time we wait for this LWP we'll see a SIGSTOP as
1146 PTRACE_ATTACH brings it to a halt. */
1149 /* We need to wait for a stop before being able to make the
1150 next ptrace call on this LWP. */
1151 lp
->must_set_ptrace_flags
= 1;
1153 /* So that wait collects the SIGSTOP. */
1156 /* Also add the LWP to gdb's thread list, in case a
1157 matching libthread_db is not found (or the process uses
1159 add_thread (linux_target
, lp
->ptid
);
1160 set_running (linux_target
, lp
->ptid
, true);
1161 set_executing (linux_target
, lp
->ptid
, true);
1170 linux_nat_target::attach (const char *args
, int from_tty
)
1172 struct lwp_info
*lp
;
1176 /* Make sure we report all signals during attach. */
1181 inf_ptrace_target::attach (args
, from_tty
);
1183 catch (const gdb_exception_error
&ex
)
1185 pid_t pid
= parse_pid_to_attach (args
);
1186 std::string reason
= linux_ptrace_attach_fail_reason (pid
);
1188 if (!reason
.empty ())
1189 throw_error (ex
.error
, "warning: %s\n%s", reason
.c_str (),
1192 throw_error (ex
.error
, "%s", ex
.what ());
1195 /* The ptrace base target adds the main thread with (pid,0,0)
1196 format. Decorate it with lwp info. */
1197 ptid
= ptid_t (inferior_ptid
.pid (),
1198 inferior_ptid
.pid (),
1200 thread_change_ptid (linux_target
, inferior_ptid
, ptid
);
1202 /* Add the initial process as the first LWP to the list. */
1203 lp
= add_initial_lwp (ptid
);
1205 status
= linux_nat_post_attach_wait (lp
->ptid
, &lp
->signalled
);
1206 if (!WIFSTOPPED (status
))
1208 if (WIFEXITED (status
))
1210 int exit_code
= WEXITSTATUS (status
);
1212 target_terminal::ours ();
1213 target_mourn_inferior (inferior_ptid
);
1215 error (_("Unable to attach: program exited normally."));
1217 error (_("Unable to attach: program exited with code %d."),
1220 else if (WIFSIGNALED (status
))
1222 enum gdb_signal signo
;
1224 target_terminal::ours ();
1225 target_mourn_inferior (inferior_ptid
);
1227 signo
= gdb_signal_from_host (WTERMSIG (status
));
1228 error (_("Unable to attach: program terminated with signal "
1230 gdb_signal_to_name (signo
),
1231 gdb_signal_to_string (signo
));
1234 internal_error (__FILE__
, __LINE__
,
1235 _("unexpected status %d for PID %ld"),
1236 status
, (long) ptid
.lwp ());
1241 /* Save the wait status to report later. */
1243 linux_nat_debug_printf ("waitpid %ld, saving status %s",
1244 (long) lp
->ptid
.pid (), status_to_str (status
));
1246 lp
->status
= status
;
1248 /* We must attach to every LWP. If /proc is mounted, use that to
1249 find them now. The inferior may be using raw clone instead of
1250 using pthreads. But even if it is using pthreads, thread_db
1251 walks structures in the inferior's address space to find the list
1252 of threads/LWPs, and those structures may well be corrupted.
1253 Note that once thread_db is loaded, we'll still use it to list
1254 threads and associate pthread info with each LWP. */
1255 linux_proc_attach_tgid_threads (lp
->ptid
.pid (),
1256 attach_proc_task_lwp_callback
);
1258 if (target_can_async_p ())
1262 /* Get pending signal of THREAD as a host signal number, for detaching
1263 purposes. This is the signal the thread last stopped for, which we
1264 need to deliver to the thread when detaching, otherwise, it'd be
1268 get_detach_signal (struct lwp_info
*lp
)
1270 enum gdb_signal signo
= GDB_SIGNAL_0
;
1272 /* If we paused threads momentarily, we may have stored pending
1273 events in lp->status or lp->waitstatus (see stop_wait_callback),
1274 and GDB core hasn't seen any signal for those threads.
1275 Otherwise, the last signal reported to the core is found in the
1276 thread object's stop_signal.
1278 There's a corner case that isn't handled here at present. Only
1279 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1280 stop_signal make sense as a real signal to pass to the inferior.
1281 Some catchpoint related events, like
1282 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1283 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1284 those traps are debug API (ptrace in our case) related and
1285 induced; the inferior wouldn't see them if it wasn't being
1286 traced. Hence, we should never pass them to the inferior, even
1287 when set to pass state. Since this corner case isn't handled by
1288 infrun.c when proceeding with a signal, for consistency, neither
1289 do we handle it here (or elsewhere in the file we check for
1290 signal pass state). Normally SIGTRAP isn't set to pass state, so
1291 this is really a corner case. */
1293 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1294 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1295 else if (lp
->status
)
1296 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1299 struct thread_info
*tp
= find_thread_ptid (linux_target
, lp
->ptid
);
1301 if (target_is_non_stop_p () && !tp
->executing
)
1303 if (tp
->suspend
.waitstatus_pending_p
)
1304 signo
= tp
->suspend
.waitstatus
.value
.sig
;
1306 signo
= tp
->suspend
.stop_signal
;
1308 else if (!target_is_non_stop_p ())
1311 process_stratum_target
*last_target
;
1313 get_last_target_status (&last_target
, &last_ptid
, nullptr);
1315 if (last_target
== linux_target
1316 && lp
->ptid
.lwp () == last_ptid
.lwp ())
1317 signo
= tp
->suspend
.stop_signal
;
1321 if (signo
== GDB_SIGNAL_0
)
1323 linux_nat_debug_printf ("lwp %s has no pending signal",
1324 target_pid_to_str (lp
->ptid
).c_str ());
1326 else if (!signal_pass_state (signo
))
1328 linux_nat_debug_printf
1329 ("lwp %s had signal %s but it is in no pass state",
1330 target_pid_to_str (lp
->ptid
).c_str (), gdb_signal_to_string (signo
));
1334 linux_nat_debug_printf ("lwp %s has pending signal %s",
1335 target_pid_to_str (lp
->ptid
).c_str (),
1336 gdb_signal_to_string (signo
));
1338 return gdb_signal_to_host (signo
);
1344 /* Detach from LP. If SIGNO_P is non-NULL, then it points to the
1345 signal number that should be passed to the LWP when detaching.
1346 Otherwise pass any pending signal the LWP may have, if any. */
1349 detach_one_lwp (struct lwp_info
*lp
, int *signo_p
)
1351 int lwpid
= lp
->ptid
.lwp ();
1354 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1356 if (lp
->status
!= 0)
1357 linux_nat_debug_printf ("Pending %s for %s on detach.",
1358 strsignal (WSTOPSIG (lp
->status
)),
1359 target_pid_to_str (lp
->ptid
).c_str ());
1361 /* If there is a pending SIGSTOP, get rid of it. */
1364 linux_nat_debug_printf ("Sending SIGCONT to %s",
1365 target_pid_to_str (lp
->ptid
).c_str ());
1367 kill_lwp (lwpid
, SIGCONT
);
1371 if (signo_p
== NULL
)
1373 /* Pass on any pending signal for this LWP. */
1374 signo
= get_detach_signal (lp
);
1379 /* Preparing to resume may try to write registers, and fail if the
1380 lwp is zombie. If that happens, ignore the error. We'll handle
1381 it below, when detach fails with ESRCH. */
1384 linux_target
->low_prepare_to_resume (lp
);
1386 catch (const gdb_exception_error
&ex
)
1388 if (!check_ptrace_stopped_lwp_gone (lp
))
1392 if (ptrace (PTRACE_DETACH
, lwpid
, 0, signo
) < 0)
1394 int save_errno
= errno
;
1396 /* We know the thread exists, so ESRCH must mean the lwp is
1397 zombie. This can happen if one of the already-detached
1398 threads exits the whole thread group. In that case we're
1399 still attached, and must reap the lwp. */
1400 if (save_errno
== ESRCH
)
1404 ret
= my_waitpid (lwpid
, &status
, __WALL
);
1407 warning (_("Couldn't reap LWP %d while detaching: %s"),
1408 lwpid
, safe_strerror (errno
));
1410 else if (!WIFEXITED (status
) && !WIFSIGNALED (status
))
1412 warning (_("Reaping LWP %d while detaching "
1413 "returned unexpected status 0x%x"),
1419 error (_("Can't detach %s: %s"),
1420 target_pid_to_str (lp
->ptid
).c_str (),
1421 safe_strerror (save_errno
));
1425 linux_nat_debug_printf ("PTRACE_DETACH (%s, %s, 0) (OK)",
1426 target_pid_to_str (lp
->ptid
).c_str (),
1429 delete_lwp (lp
->ptid
);
1433 detach_callback (struct lwp_info
*lp
)
1435 /* We don't actually detach from the thread group leader just yet.
1436 If the thread group exits, we must reap the zombie clone lwps
1437 before we're able to reap the leader. */
1438 if (lp
->ptid
.lwp () != lp
->ptid
.pid ())
1439 detach_one_lwp (lp
, NULL
);
1444 linux_nat_target::detach (inferior
*inf
, int from_tty
)
1446 struct lwp_info
*main_lwp
;
1449 /* Don't unregister from the event loop, as there may be other
1450 inferiors running. */
1452 /* Stop all threads before detaching. ptrace requires that the
1453 thread is stopped to successfully detach. */
1454 iterate_over_lwps (ptid_t (pid
), stop_callback
);
1455 /* ... and wait until all of them have reported back that
1456 they're no longer running. */
1457 iterate_over_lwps (ptid_t (pid
), stop_wait_callback
);
1459 iterate_over_lwps (ptid_t (pid
), detach_callback
);
1461 /* Only the initial process should be left right now. */
1462 gdb_assert (num_lwps (pid
) == 1);
1464 main_lwp
= find_lwp_pid (ptid_t (pid
));
1466 if (forks_exist_p ())
1468 /* Multi-fork case. The current inferior_ptid is being detached
1469 from, but there are other viable forks to debug. Detach from
1470 the current fork, and context-switch to the first
1472 linux_fork_detach (from_tty
);
1476 target_announce_detach (from_tty
);
1478 /* Pass on any pending signal for the last LWP. */
1479 int signo
= get_detach_signal (main_lwp
);
1481 detach_one_lwp (main_lwp
, &signo
);
1483 detach_success (inf
);
1487 /* Resume execution of the inferior process. If STEP is nonzero,
1488 single-step it. If SIGNAL is nonzero, give it that signal. */
1491 linux_resume_one_lwp_throw (struct lwp_info
*lp
, int step
,
1492 enum gdb_signal signo
)
1496 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1497 We only presently need that if the LWP is stepped though (to
1498 handle the case of stepping a breakpoint instruction). */
1501 struct regcache
*regcache
= get_thread_regcache (linux_target
, lp
->ptid
);
1503 lp
->stop_pc
= regcache_read_pc (regcache
);
1508 linux_target
->low_prepare_to_resume (lp
);
1509 linux_target
->low_resume (lp
->ptid
, step
, signo
);
1511 /* Successfully resumed. Clear state that no longer makes sense,
1512 and mark the LWP as running. Must not do this before resuming
1513 otherwise if that fails other code will be confused. E.g., we'd
1514 later try to stop the LWP and hang forever waiting for a stop
1515 status. Note that we must not throw after this is cleared,
1516 otherwise handle_zombie_lwp_error would get confused. */
1519 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1520 registers_changed_ptid (linux_target
, lp
->ptid
);
1523 /* Called when we try to resume a stopped LWP and that errors out. If
1524 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1525 or about to become), discard the error, clear any pending status
1526 the LWP may have, and return true (we'll collect the exit status
1527 soon enough). Otherwise, return false. */
1530 check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
)
1532 /* If we get an error after resuming the LWP successfully, we'd
1533 confuse !T state for the LWP being gone. */
1534 gdb_assert (lp
->stopped
);
1536 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1537 because even if ptrace failed with ESRCH, the tracee may be "not
1538 yet fully dead", but already refusing ptrace requests. In that
1539 case the tracee has 'R (Running)' state for a little bit
1540 (observed in Linux 3.18). See also the note on ESRCH in the
1541 ptrace(2) man page. Instead, check whether the LWP has any state
1542 other than ptrace-stopped. */
1544 /* Don't assume anything if /proc/PID/status can't be read. */
1545 if (linux_proc_pid_is_trace_stopped_nowarn (lp
->ptid
.lwp ()) == 0)
1547 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1549 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
1555 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1556 disappears while we try to resume it. */
1559 linux_resume_one_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1563 linux_resume_one_lwp_throw (lp
, step
, signo
);
1565 catch (const gdb_exception_error
&ex
)
1567 if (!check_ptrace_stopped_lwp_gone (lp
))
1575 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1579 struct inferior
*inf
= find_inferior_ptid (linux_target
, lp
->ptid
);
1581 if (inf
->vfork_child
!= NULL
)
1583 linux_nat_debug_printf ("Not resuming %s (vfork parent)",
1584 target_pid_to_str (lp
->ptid
).c_str ());
1586 else if (!lwp_status_pending_p (lp
))
1588 linux_nat_debug_printf ("Resuming sibling %s, %s, %s",
1589 target_pid_to_str (lp
->ptid
).c_str (),
1590 (signo
!= GDB_SIGNAL_0
1591 ? strsignal (gdb_signal_to_host (signo
))
1593 step
? "step" : "resume");
1595 linux_resume_one_lwp (lp
, step
, signo
);
1599 linux_nat_debug_printf ("Not resuming sibling %s (has pending)",
1600 target_pid_to_str (lp
->ptid
).c_str ());
1604 linux_nat_debug_printf ("Not resuming sibling %s (not stopped)",
1605 target_pid_to_str (lp
->ptid
).c_str ());
1608 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1609 Resume LWP with the last stop signal, if it is in pass state. */
1612 linux_nat_resume_callback (struct lwp_info
*lp
, struct lwp_info
*except
)
1614 enum gdb_signal signo
= GDB_SIGNAL_0
;
1621 struct thread_info
*thread
;
1623 thread
= find_thread_ptid (linux_target
, lp
->ptid
);
1626 signo
= thread
->suspend
.stop_signal
;
1627 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1631 resume_lwp (lp
, 0, signo
);
1636 resume_clear_callback (struct lwp_info
*lp
)
1639 lp
->last_resume_kind
= resume_stop
;
1644 resume_set_callback (struct lwp_info
*lp
)
1647 lp
->last_resume_kind
= resume_continue
;
1652 linux_nat_target::resume (ptid_t ptid
, int step
, enum gdb_signal signo
)
1654 struct lwp_info
*lp
;
1657 linux_nat_debug_printf ("Preparing to %s %s, %s, inferior_ptid %s",
1658 step
? "step" : "resume",
1659 target_pid_to_str (ptid
).c_str (),
1660 (signo
!= GDB_SIGNAL_0
1661 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1662 target_pid_to_str (inferior_ptid
).c_str ());
1664 /* A specific PTID means `step only this process id'. */
1665 resume_many
= (minus_one_ptid
== ptid
1668 /* Mark the lwps we're resuming as resumed and update their
1669 last_resume_kind to resume_continue. */
1670 iterate_over_lwps (ptid
, resume_set_callback
);
1672 /* See if it's the current inferior that should be handled
1675 lp
= find_lwp_pid (inferior_ptid
);
1677 lp
= find_lwp_pid (ptid
);
1678 gdb_assert (lp
!= NULL
);
1680 /* Remember if we're stepping. */
1681 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1683 /* If we have a pending wait status for this thread, there is no
1684 point in resuming the process. But first make sure that
1685 linux_nat_wait won't preemptively handle the event - we
1686 should never take this short-circuit if we are going to
1687 leave LP running, since we have skipped resuming all the
1688 other threads. This bit of code needs to be synchronized
1689 with linux_nat_wait. */
1691 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1694 && WSTOPSIG (lp
->status
)
1695 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1697 linux_nat_debug_printf
1698 ("Not short circuiting for ignored status 0x%x", lp
->status
);
1700 /* FIXME: What should we do if we are supposed to continue
1701 this thread with a signal? */
1702 gdb_assert (signo
== GDB_SIGNAL_0
);
1703 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1708 if (lwp_status_pending_p (lp
))
1710 /* FIXME: What should we do if we are supposed to continue
1711 this thread with a signal? */
1712 gdb_assert (signo
== GDB_SIGNAL_0
);
1714 linux_nat_debug_printf ("Short circuiting for status 0x%x",
1717 if (target_can_async_p ())
1720 /* Tell the event loop we have something to process. */
1727 iterate_over_lwps (ptid
, [=] (struct lwp_info
*info
)
1729 return linux_nat_resume_callback (info
, lp
);
1732 linux_nat_debug_printf ("%s %s, %s (resume event thread)",
1733 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1734 target_pid_to_str (lp
->ptid
).c_str (),
1735 (signo
!= GDB_SIGNAL_0
1736 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1738 linux_resume_one_lwp (lp
, step
, signo
);
1740 if (target_can_async_p ())
1744 /* Send a signal to an LWP. */
1747 kill_lwp (int lwpid
, int signo
)
1752 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1753 if (errno
== ENOSYS
)
1755 /* If tkill fails, then we are not using nptl threads, a
1756 configuration we no longer support. */
1757 perror_with_name (("tkill"));
1762 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1763 event, check if the core is interested in it: if not, ignore the
1764 event, and keep waiting; otherwise, we need to toggle the LWP's
1765 syscall entry/exit status, since the ptrace event itself doesn't
1766 indicate it, and report the trap to higher layers. */
1769 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1771 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1772 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1773 thread_info
*thread
= find_thread_ptid (linux_target
, lp
->ptid
);
1774 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, thread
);
1778 /* If we're stopping threads, there's a SIGSTOP pending, which
1779 makes it so that the LWP reports an immediate syscall return,
1780 followed by the SIGSTOP. Skip seeing that "return" using
1781 PTRACE_CONT directly, and let stop_wait_callback collect the
1782 SIGSTOP. Later when the thread is resumed, a new syscall
1783 entry event. If we didn't do this (and returned 0), we'd
1784 leave a syscall entry pending, and our caller, by using
1785 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1786 itself. Later, when the user re-resumes this LWP, we'd see
1787 another syscall entry event and we'd mistake it for a return.
1789 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1790 (leaving immediately with LWP->signalled set, without issuing
1791 a PTRACE_CONT), it would still be problematic to leave this
1792 syscall enter pending, as later when the thread is resumed,
1793 it would then see the same syscall exit mentioned above,
1794 followed by the delayed SIGSTOP, while the syscall didn't
1795 actually get to execute. It seems it would be even more
1796 confusing to the user. */
1798 linux_nat_debug_printf
1799 ("ignoring syscall %d for LWP %ld (stopping threads), resuming with "
1800 "PTRACE_CONT for SIGSTOP", syscall_number
, lp
->ptid
.lwp ());
1802 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1803 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
1808 /* Always update the entry/return state, even if this particular
1809 syscall isn't interesting to the core now. In async mode,
1810 the user could install a new catchpoint for this syscall
1811 between syscall enter/return, and we'll need to know to
1812 report a syscall return if that happens. */
1813 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1814 ? TARGET_WAITKIND_SYSCALL_RETURN
1815 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1817 if (catch_syscall_enabled ())
1819 if (catching_syscall_number (syscall_number
))
1821 /* Alright, an event to report. */
1822 ourstatus
->kind
= lp
->syscall_state
;
1823 ourstatus
->value
.syscall_number
= syscall_number
;
1825 linux_nat_debug_printf
1826 ("stopping for %s of syscall %d for LWP %ld",
1827 (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1828 ? "entry" : "return"), syscall_number
, lp
->ptid
.lwp ());
1833 linux_nat_debug_printf
1834 ("ignoring %s of syscall %d for LWP %ld",
1835 (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1836 ? "entry" : "return"), syscall_number
, lp
->ptid
.lwp ());
1840 /* If we had been syscall tracing, and hence used PT_SYSCALL
1841 before on this LWP, it could happen that the user removes all
1842 syscall catchpoints before we get to process this event.
1843 There are two noteworthy issues here:
1845 - When stopped at a syscall entry event, resuming with
1846 PT_STEP still resumes executing the syscall and reports a
1849 - Only PT_SYSCALL catches syscall enters. If we last
1850 single-stepped this thread, then this event can't be a
1851 syscall enter. If we last single-stepped this thread, this
1852 has to be a syscall exit.
1854 The points above mean that the next resume, be it PT_STEP or
1855 PT_CONTINUE, can not trigger a syscall trace event. */
1856 linux_nat_debug_printf
1857 ("caught syscall event with no syscall catchpoints. %d for LWP %ld, "
1858 "ignoring", syscall_number
, lp
->ptid
.lwp ());
1859 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1862 /* The core isn't interested in this event. For efficiency, avoid
1863 stopping all threads only to have the core resume them all again.
1864 Since we're not stopping threads, if we're still syscall tracing
1865 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1866 subsequent syscall. Simply resume using the inf-ptrace layer,
1867 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1869 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
1873 /* Handle a GNU/Linux extended wait response. If we see a clone
1874 event, we need to add the new LWP to our list (and not report the
1875 trap to higher layers). This function returns non-zero if the
1876 event should be ignored and we should wait again. If STOPPING is
1877 true, the new LWP remains stopped, otherwise it is continued. */
1880 linux_handle_extended_wait (struct lwp_info
*lp
, int status
)
1882 int pid
= lp
->ptid
.lwp ();
1883 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1884 int event
= linux_ptrace_get_extended_event (status
);
1886 /* All extended events we currently use are mid-syscall. Only
1887 PTRACE_EVENT_STOP is delivered more like a signal-stop, but
1888 you have to be using PTRACE_SEIZE to get that. */
1889 lp
->syscall_state
= TARGET_WAITKIND_SYSCALL_ENTRY
;
1891 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1892 || event
== PTRACE_EVENT_CLONE
)
1894 unsigned long new_pid
;
1897 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1899 /* If we haven't already seen the new PID stop, wait for it now. */
1900 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1902 /* The new child has a pending SIGSTOP. We can't affect it until it
1903 hits the SIGSTOP, but we're already attached. */
1904 ret
= my_waitpid (new_pid
, &status
, __WALL
);
1906 perror_with_name (_("waiting for new child"));
1907 else if (ret
!= new_pid
)
1908 internal_error (__FILE__
, __LINE__
,
1909 _("wait returned unexpected PID %d"), ret
);
1910 else if (!WIFSTOPPED (status
))
1911 internal_error (__FILE__
, __LINE__
,
1912 _("wait returned unexpected status 0x%x"), status
);
1915 ourstatus
->value
.related_pid
= ptid_t (new_pid
, new_pid
, 0);
1917 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
1919 /* The arch-specific native code may need to know about new
1920 forks even if those end up never mapped to an
1922 linux_target
->low_new_fork (lp
, new_pid
);
1924 else if (event
== PTRACE_EVENT_CLONE
)
1926 linux_target
->low_new_clone (lp
, new_pid
);
1929 if (event
== PTRACE_EVENT_FORK
1930 && linux_fork_checkpointing_p (lp
->ptid
.pid ()))
1932 /* Handle checkpointing by linux-fork.c here as a special
1933 case. We don't want the follow-fork-mode or 'catch fork'
1934 to interfere with this. */
1936 /* This won't actually modify the breakpoint list, but will
1937 physically remove the breakpoints from the child. */
1938 detach_breakpoints (ptid_t (new_pid
, new_pid
, 0));
1940 /* Retain child fork in ptrace (stopped) state. */
1941 if (!find_fork_pid (new_pid
))
1944 /* Report as spurious, so that infrun doesn't want to follow
1945 this fork. We're actually doing an infcall in
1947 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
1949 /* Report the stop to the core. */
1953 if (event
== PTRACE_EVENT_FORK
)
1954 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
1955 else if (event
== PTRACE_EVENT_VFORK
)
1956 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
1957 else if (event
== PTRACE_EVENT_CLONE
)
1959 struct lwp_info
*new_lp
;
1961 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
1963 linux_nat_debug_printf
1964 ("Got clone event from LWP %d, new child is LWP %ld", pid
, new_pid
);
1966 new_lp
= add_lwp (ptid_t (lp
->ptid
.pid (), new_pid
, 0));
1967 new_lp
->stopped
= 1;
1968 new_lp
->resumed
= 1;
1970 /* If the thread_db layer is active, let it record the user
1971 level thread id and status, and add the thread to GDB's
1973 if (!thread_db_notice_clone (lp
->ptid
, new_lp
->ptid
))
1975 /* The process is not using thread_db. Add the LWP to
1977 target_post_attach (new_lp
->ptid
.lwp ());
1978 add_thread (linux_target
, new_lp
->ptid
);
1981 /* Even if we're stopping the thread for some reason
1982 internal to this module, from the perspective of infrun
1983 and the user/frontend, this new thread is running until
1984 it next reports a stop. */
1985 set_running (linux_target
, new_lp
->ptid
, true);
1986 set_executing (linux_target
, new_lp
->ptid
, true);
1988 if (WSTOPSIG (status
) != SIGSTOP
)
1990 /* This can happen if someone starts sending signals to
1991 the new thread before it gets a chance to run, which
1992 have a lower number than SIGSTOP (e.g. SIGUSR1).
1993 This is an unlikely case, and harder to handle for
1994 fork / vfork than for clone, so we do not try - but
1995 we handle it for clone events here. */
1997 new_lp
->signalled
= 1;
1999 /* We created NEW_LP so it cannot yet contain STATUS. */
2000 gdb_assert (new_lp
->status
== 0);
2002 /* Save the wait status to report later. */
2003 linux_nat_debug_printf
2004 ("waitpid of new LWP %ld, saving status %s",
2005 (long) new_lp
->ptid
.lwp (), status_to_str (status
));
2006 new_lp
->status
= status
;
2008 else if (report_thread_events
)
2010 new_lp
->waitstatus
.kind
= TARGET_WAITKIND_THREAD_CREATED
;
2011 new_lp
->status
= status
;
2020 if (event
== PTRACE_EVENT_EXEC
)
2022 linux_nat_debug_printf ("Got exec event from LWP %ld", lp
->ptid
.lwp ());
2024 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2025 ourstatus
->value
.execd_pathname
2026 = xstrdup (linux_proc_pid_to_exec_file (pid
));
2028 /* The thread that execed must have been resumed, but, when a
2029 thread execs, it changes its tid to the tgid, and the old
2030 tgid thread might have not been resumed. */
2035 if (event
== PTRACE_EVENT_VFORK_DONE
)
2037 if (current_inferior ()->waiting_for_vfork_done
)
2039 linux_nat_debug_printf
2040 ("Got expected PTRACE_EVENT_VFORK_DONE from LWP %ld: stopping",
2043 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2047 linux_nat_debug_printf
2048 ("Got PTRACE_EVENT_VFORK_DONE from LWP %ld: ignoring", lp
->ptid
.lwp ());
2053 internal_error (__FILE__
, __LINE__
,
2054 _("unknown ptrace event %d"), event
);
2057 /* Suspend waiting for a signal. We're mostly interested in
2063 linux_nat_debug_printf ("about to sigsuspend");
2064 sigsuspend (&suspend_mask
);
2066 /* If the quit flag is set, it means that the user pressed Ctrl-C
2067 and we're debugging a process that is running on a separate
2068 terminal, so we must forward the Ctrl-C to the inferior. (If the
2069 inferior is sharing GDB's terminal, then the Ctrl-C reaches the
2070 inferior directly.) We must do this here because functions that
2071 need to block waiting for a signal loop forever until there's an
2072 event to report before returning back to the event loop. */
2073 if (!target_terminal::is_ours ())
2075 if (check_quit_flag ())
2076 target_pass_ctrlc ();
2080 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2084 wait_lwp (struct lwp_info
*lp
)
2088 int thread_dead
= 0;
2091 gdb_assert (!lp
->stopped
);
2092 gdb_assert (lp
->status
== 0);
2094 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2095 block_child_signals (&prev_mask
);
2099 pid
= my_waitpid (lp
->ptid
.lwp (), &status
, __WALL
| WNOHANG
);
2100 if (pid
== -1 && errno
== ECHILD
)
2102 /* The thread has previously exited. We need to delete it
2103 now because if this was a non-leader thread execing, we
2104 won't get an exit event. See comments on exec events at
2105 the top of the file. */
2107 linux_nat_debug_printf ("%s vanished.",
2108 target_pid_to_str (lp
->ptid
).c_str ());
2113 /* Bugs 10970, 12702.
2114 Thread group leader may have exited in which case we'll lock up in
2115 waitpid if there are other threads, even if they are all zombies too.
2116 Basically, we're not supposed to use waitpid this way.
2117 tkill(pid,0) cannot be used here as it gets ESRCH for both
2118 for zombie and running processes.
2120 As a workaround, check if we're waiting for the thread group leader and
2121 if it's a zombie, and avoid calling waitpid if it is.
2123 This is racy, what if the tgl becomes a zombie right after we check?
2124 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2125 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2127 if (lp
->ptid
.pid () == lp
->ptid
.lwp ()
2128 && linux_proc_pid_is_zombie (lp
->ptid
.lwp ()))
2131 linux_nat_debug_printf ("Thread group leader %s vanished.",
2132 target_pid_to_str (lp
->ptid
).c_str ());
2136 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2137 get invoked despite our caller had them intentionally blocked by
2138 block_child_signals. This is sensitive only to the loop of
2139 linux_nat_wait_1 and there if we get called my_waitpid gets called
2140 again before it gets to sigsuspend so we can safely let the handlers
2141 get executed here. */
2145 restore_child_signals_mask (&prev_mask
);
2149 gdb_assert (pid
== lp
->ptid
.lwp ());
2151 linux_nat_debug_printf ("waitpid %s received %s",
2152 target_pid_to_str (lp
->ptid
).c_str (),
2153 status_to_str (status
));
2155 /* Check if the thread has exited. */
2156 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2158 if (report_thread_events
2159 || lp
->ptid
.pid () == lp
->ptid
.lwp ())
2161 linux_nat_debug_printf ("LWP %d exited.", lp
->ptid
.pid ());
2163 /* If this is the leader exiting, it means the whole
2164 process is gone. Store the status to report to the
2165 core. Store it in lp->waitstatus, because lp->status
2166 would be ambiguous (W_EXITCODE(0,0) == 0). */
2167 store_waitstatus (&lp
->waitstatus
, status
);
2172 linux_nat_debug_printf ("%s exited.",
2173 target_pid_to_str (lp
->ptid
).c_str ());
2183 gdb_assert (WIFSTOPPED (status
));
2186 if (lp
->must_set_ptrace_flags
)
2188 inferior
*inf
= find_inferior_pid (linux_target
, lp
->ptid
.pid ());
2189 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2191 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2192 lp
->must_set_ptrace_flags
= 0;
2195 /* Handle GNU/Linux's syscall SIGTRAPs. */
2196 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2198 /* No longer need the sysgood bit. The ptrace event ends up
2199 recorded in lp->waitstatus if we care for it. We can carry
2200 on handling the event like a regular SIGTRAP from here
2202 status
= W_STOPCODE (SIGTRAP
);
2203 if (linux_handle_syscall_trap (lp
, 1))
2204 return wait_lwp (lp
);
2208 /* Almost all other ptrace-stops are known to be outside of system
2209 calls, with further exceptions in linux_handle_extended_wait. */
2210 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
2213 /* Handle GNU/Linux's extended waitstatus for trace events. */
2214 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2215 && linux_is_extended_waitstatus (status
))
2217 linux_nat_debug_printf ("Handling extended status 0x%06x", status
);
2218 linux_handle_extended_wait (lp
, status
);
2225 /* Send a SIGSTOP to LP. */
2228 stop_callback (struct lwp_info
*lp
)
2230 if (!lp
->stopped
&& !lp
->signalled
)
2234 linux_nat_debug_printf ("kill %s **<SIGSTOP>**",
2235 target_pid_to_str (lp
->ptid
).c_str ());
2238 ret
= kill_lwp (lp
->ptid
.lwp (), SIGSTOP
);
2239 linux_nat_debug_printf ("lwp kill %d %s", ret
,
2240 errno
? safe_strerror (errno
) : "ERRNO-OK");
2243 gdb_assert (lp
->status
== 0);
2249 /* Request a stop on LWP. */
2252 linux_stop_lwp (struct lwp_info
*lwp
)
2254 stop_callback (lwp
);
2257 /* See linux-nat.h */
2260 linux_stop_and_wait_all_lwps (void)
2262 /* Stop all LWP's ... */
2263 iterate_over_lwps (minus_one_ptid
, stop_callback
);
2265 /* ... and wait until all of them have reported back that
2266 they're no longer running. */
2267 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
);
2270 /* See linux-nat.h */
2273 linux_unstop_all_lwps (void)
2275 iterate_over_lwps (minus_one_ptid
,
2276 [] (struct lwp_info
*info
)
2278 return resume_stopped_resumed_lwps (info
, minus_one_ptid
);
2282 /* Return non-zero if LWP PID has a pending SIGINT. */
2285 linux_nat_has_pending_sigint (int pid
)
2287 sigset_t pending
, blocked
, ignored
;
2289 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2291 if (sigismember (&pending
, SIGINT
)
2292 && !sigismember (&ignored
, SIGINT
))
2298 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2301 set_ignore_sigint (struct lwp_info
*lp
)
2303 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2304 flag to consume the next one. */
2305 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2306 && WSTOPSIG (lp
->status
) == SIGINT
)
2309 lp
->ignore_sigint
= 1;
2314 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2315 This function is called after we know the LWP has stopped; if the LWP
2316 stopped before the expected SIGINT was delivered, then it will never have
2317 arrived. Also, if the signal was delivered to a shared queue and consumed
2318 by a different thread, it will never be delivered to this LWP. */
2321 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2323 if (!lp
->ignore_sigint
)
2326 if (!linux_nat_has_pending_sigint (lp
->ptid
.lwp ()))
2328 linux_nat_debug_printf ("Clearing bogus flag for %s",
2329 target_pid_to_str (lp
->ptid
).c_str ());
2330 lp
->ignore_sigint
= 0;
2334 /* Fetch the possible triggered data watchpoint info and store it in
2337 On some archs, like x86, that use debug registers to set
2338 watchpoints, it's possible that the way to know which watched
2339 address trapped, is to check the register that is used to select
2340 which address to watch. Problem is, between setting the watchpoint
2341 and reading back which data address trapped, the user may change
2342 the set of watchpoints, and, as a consequence, GDB changes the
2343 debug registers in the inferior. To avoid reading back a stale
2344 stopped-data-address when that happens, we cache in LP the fact
2345 that a watchpoint trapped, and the corresponding data address, as
2346 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2347 registers meanwhile, we have the cached data we can rely on. */
2350 check_stopped_by_watchpoint (struct lwp_info
*lp
)
2352 scoped_restore save_inferior_ptid
= make_scoped_restore (&inferior_ptid
);
2353 inferior_ptid
= lp
->ptid
;
2355 if (linux_target
->low_stopped_by_watchpoint ())
2357 lp
->stop_reason
= TARGET_STOPPED_BY_WATCHPOINT
;
2358 lp
->stopped_data_address_p
2359 = linux_target
->low_stopped_data_address (&lp
->stopped_data_address
);
2362 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2365 /* Returns true if the LWP had stopped for a watchpoint. */
2368 linux_nat_target::stopped_by_watchpoint ()
2370 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2372 gdb_assert (lp
!= NULL
);
2374 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2378 linux_nat_target::stopped_data_address (CORE_ADDR
*addr_p
)
2380 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2382 gdb_assert (lp
!= NULL
);
2384 *addr_p
= lp
->stopped_data_address
;
2386 return lp
->stopped_data_address_p
;
2389 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2392 linux_nat_target::low_status_is_event (int status
)
2394 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2397 /* Wait until LP is stopped. */
2400 stop_wait_callback (struct lwp_info
*lp
)
2402 inferior
*inf
= find_inferior_ptid (linux_target
, lp
->ptid
);
2404 /* If this is a vfork parent, bail out, it is not going to report
2405 any SIGSTOP until the vfork is done with. */
2406 if (inf
->vfork_child
!= NULL
)
2413 status
= wait_lwp (lp
);
2417 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2418 && WSTOPSIG (status
) == SIGINT
)
2420 lp
->ignore_sigint
= 0;
2423 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
2425 linux_nat_debug_printf
2426 ("PTRACE_CONT %s, 0, 0 (%s) (discarding SIGINT)",
2427 target_pid_to_str (lp
->ptid
).c_str (),
2428 errno
? safe_strerror (errno
) : "OK");
2430 return stop_wait_callback (lp
);
2433 maybe_clear_ignore_sigint (lp
);
2435 if (WSTOPSIG (status
) != SIGSTOP
)
2437 /* The thread was stopped with a signal other than SIGSTOP. */
2439 linux_nat_debug_printf ("Pending event %s in %s",
2440 status_to_str ((int) status
),
2441 target_pid_to_str (lp
->ptid
).c_str ());
2443 /* Save the sigtrap event. */
2444 lp
->status
= status
;
2445 gdb_assert (lp
->signalled
);
2446 save_stop_reason (lp
);
2450 /* We caught the SIGSTOP that we intended to catch. */
2452 linux_nat_debug_printf ("Expected SIGSTOP caught for %s.",
2453 target_pid_to_str (lp
->ptid
).c_str ());
2457 /* If we are waiting for this stop so we can report the thread
2458 stopped then we need to record this status. Otherwise, we can
2459 now discard this stop event. */
2460 if (lp
->last_resume_kind
== resume_stop
)
2462 lp
->status
= status
;
2463 save_stop_reason (lp
);
2471 /* Return non-zero if LP has a wait status pending. Discard the
2472 pending event and resume the LWP if the event that originally
2473 caused the stop became uninteresting. */
2476 status_callback (struct lwp_info
*lp
)
2478 /* Only report a pending wait status if we pretend that this has
2479 indeed been resumed. */
2483 if (!lwp_status_pending_p (lp
))
2486 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
2487 || lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2489 struct regcache
*regcache
= get_thread_regcache (linux_target
, lp
->ptid
);
2493 pc
= regcache_read_pc (regcache
);
2495 if (pc
!= lp
->stop_pc
)
2497 linux_nat_debug_printf ("PC of %s changed. was=%s, now=%s",
2498 target_pid_to_str (lp
->ptid
).c_str (),
2499 paddress (target_gdbarch (), lp
->stop_pc
),
2500 paddress (target_gdbarch (), pc
));
2504 #if !USE_SIGTRAP_SIGINFO
2505 else if (!breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2507 linux_nat_debug_printf ("previous breakpoint of %s, at %s gone",
2508 target_pid_to_str (lp
->ptid
).c_str (),
2509 paddress (target_gdbarch (), lp
->stop_pc
));
2517 linux_nat_debug_printf ("pending event of %s cancelled.",
2518 target_pid_to_str (lp
->ptid
).c_str ());
2521 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2529 /* Count the LWP's that have had events. */
2532 count_events_callback (struct lwp_info
*lp
, int *count
)
2534 gdb_assert (count
!= NULL
);
2536 /* Select only resumed LWPs that have an event pending. */
2537 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2543 /* Select the LWP (if any) that is currently being single-stepped. */
2546 select_singlestep_lwp_callback (struct lwp_info
*lp
)
2548 if (lp
->last_resume_kind
== resume_step
2555 /* Returns true if LP has a status pending. */
2558 lwp_status_pending_p (struct lwp_info
*lp
)
2560 /* We check for lp->waitstatus in addition to lp->status, because we
2561 can have pending process exits recorded in lp->status and
2562 W_EXITCODE(0,0) happens to be 0. */
2563 return lp
->status
!= 0 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
;
2566 /* Select the Nth LWP that has had an event. */
2569 select_event_lwp_callback (struct lwp_info
*lp
, int *selector
)
2571 gdb_assert (selector
!= NULL
);
2573 /* Select only resumed LWPs that have an event pending. */
2574 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2575 if ((*selector
)-- == 0)
2581 /* Called when the LWP stopped for a signal/trap. If it stopped for a
2582 trap check what caused it (breakpoint, watchpoint, trace, etc.),
2583 and save the result in the LWP's stop_reason field. If it stopped
2584 for a breakpoint, decrement the PC if necessary on the lwp's
2588 save_stop_reason (struct lwp_info
*lp
)
2590 struct regcache
*regcache
;
2591 struct gdbarch
*gdbarch
;
2594 #if USE_SIGTRAP_SIGINFO
2598 gdb_assert (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
);
2599 gdb_assert (lp
->status
!= 0);
2601 if (!linux_target
->low_status_is_event (lp
->status
))
2604 regcache
= get_thread_regcache (linux_target
, lp
->ptid
);
2605 gdbarch
= regcache
->arch ();
2607 pc
= regcache_read_pc (regcache
);
2608 sw_bp_pc
= pc
- gdbarch_decr_pc_after_break (gdbarch
);
2610 #if USE_SIGTRAP_SIGINFO
2611 if (linux_nat_get_siginfo (lp
->ptid
, &siginfo
))
2613 if (siginfo
.si_signo
== SIGTRAP
)
2615 if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
)
2616 && GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2618 /* The si_code is ambiguous on this arch -- check debug
2620 if (!check_stopped_by_watchpoint (lp
))
2621 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2623 else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
))
2625 /* If we determine the LWP stopped for a SW breakpoint,
2626 trust it. Particularly don't check watchpoint
2627 registers, because, at least on s390, we'd find
2628 stopped-by-watchpoint as long as there's a watchpoint
2630 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2632 else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2634 /* This can indicate either a hardware breakpoint or
2635 hardware watchpoint. Check debug registers. */
2636 if (!check_stopped_by_watchpoint (lp
))
2637 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2639 else if (siginfo
.si_code
== TRAP_TRACE
)
2641 linux_nat_debug_printf ("%s stopped by trace",
2642 target_pid_to_str (lp
->ptid
).c_str ());
2644 /* We may have single stepped an instruction that
2645 triggered a watchpoint. In that case, on some
2646 architectures (such as x86), instead of TRAP_HWBKPT,
2647 si_code indicates TRAP_TRACE, and we need to check
2648 the debug registers separately. */
2649 check_stopped_by_watchpoint (lp
);
2654 if ((!lp
->step
|| lp
->stop_pc
== sw_bp_pc
)
2655 && software_breakpoint_inserted_here_p (regcache
->aspace (),
2658 /* The LWP was either continued, or stepped a software
2659 breakpoint instruction. */
2660 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2663 if (hardware_breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2664 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2666 if (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
)
2667 check_stopped_by_watchpoint (lp
);
2670 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
)
2672 linux_nat_debug_printf ("%s stopped by software breakpoint",
2673 target_pid_to_str (lp
->ptid
).c_str ());
2675 /* Back up the PC if necessary. */
2677 regcache_write_pc (regcache
, sw_bp_pc
);
2679 /* Update this so we record the correct stop PC below. */
2682 else if (lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2684 linux_nat_debug_printf ("%s stopped by hardware breakpoint",
2685 target_pid_to_str (lp
->ptid
).c_str ());
2687 else if (lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
)
2689 linux_nat_debug_printf ("%s stopped by hardware watchpoint",
2690 target_pid_to_str (lp
->ptid
).c_str ());
2697 /* Returns true if the LWP had stopped for a software breakpoint. */
2700 linux_nat_target::stopped_by_sw_breakpoint ()
2702 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2704 gdb_assert (lp
!= NULL
);
2706 return lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
;
2709 /* Implement the supports_stopped_by_sw_breakpoint method. */
2712 linux_nat_target::supports_stopped_by_sw_breakpoint ()
2714 return USE_SIGTRAP_SIGINFO
;
2717 /* Returns true if the LWP had stopped for a hardware
2718 breakpoint/watchpoint. */
2721 linux_nat_target::stopped_by_hw_breakpoint ()
2723 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2725 gdb_assert (lp
!= NULL
);
2727 return lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
;
2730 /* Implement the supports_stopped_by_hw_breakpoint method. */
2733 linux_nat_target::supports_stopped_by_hw_breakpoint ()
2735 return USE_SIGTRAP_SIGINFO
;
2738 /* Select one LWP out of those that have events pending. */
2741 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2744 int random_selector
;
2745 struct lwp_info
*event_lp
= NULL
;
2747 /* Record the wait status for the original LWP. */
2748 (*orig_lp
)->status
= *status
;
2750 /* In all-stop, give preference to the LWP that is being
2751 single-stepped. There will be at most one, and it will be the
2752 LWP that the core is most interested in. If we didn't do this,
2753 then we'd have to handle pending step SIGTRAPs somehow in case
2754 the core later continues the previously-stepped thread, as
2755 otherwise we'd report the pending SIGTRAP then, and the core, not
2756 having stepped the thread, wouldn't understand what the trap was
2757 for, and therefore would report it to the user as a random
2759 if (!target_is_non_stop_p ())
2761 event_lp
= iterate_over_lwps (filter
, select_singlestep_lwp_callback
);
2762 if (event_lp
!= NULL
)
2764 linux_nat_debug_printf ("Select single-step %s",
2765 target_pid_to_str (event_lp
->ptid
).c_str ());
2769 if (event_lp
== NULL
)
2771 /* Pick one at random, out of those which have had events. */
2773 /* First see how many events we have. */
2774 iterate_over_lwps (filter
,
2775 [&] (struct lwp_info
*info
)
2777 return count_events_callback (info
, &num_events
);
2779 gdb_assert (num_events
> 0);
2781 /* Now randomly pick a LWP out of those that have had
2783 random_selector
= (int)
2784 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2787 linux_nat_debug_printf ("Found %d events, selecting #%d",
2788 num_events
, random_selector
);
2791 = (iterate_over_lwps
2793 [&] (struct lwp_info
*info
)
2795 return select_event_lwp_callback (info
,
2800 if (event_lp
!= NULL
)
2802 /* Switch the event LWP. */
2803 *orig_lp
= event_lp
;
2804 *status
= event_lp
->status
;
2807 /* Flush the wait status for the event LWP. */
2808 (*orig_lp
)->status
= 0;
2811 /* Return non-zero if LP has been resumed. */
2814 resumed_callback (struct lwp_info
*lp
)
2819 /* Check if we should go on and pass this event to common code.
2820 Return the affected lwp if we should, or NULL otherwise. */
2822 static struct lwp_info
*
2823 linux_nat_filter_event (int lwpid
, int status
)
2825 struct lwp_info
*lp
;
2826 int event
= linux_ptrace_get_extended_event (status
);
2828 lp
= find_lwp_pid (ptid_t (lwpid
));
2830 /* Check for stop events reported by a process we didn't already
2831 know about - anything not already in our LWP list.
2833 If we're expecting to receive stopped processes after
2834 fork, vfork, and clone events, then we'll just add the
2835 new one to our list and go back to waiting for the event
2836 to be reported - the stopped process might be returned
2837 from waitpid before or after the event is.
2839 But note the case of a non-leader thread exec'ing after the
2840 leader having exited, and gone from our lists. The non-leader
2841 thread changes its tid to the tgid. */
2843 if (WIFSTOPPED (status
) && lp
== NULL
2844 && (WSTOPSIG (status
) == SIGTRAP
&& event
== PTRACE_EVENT_EXEC
))
2846 /* A multi-thread exec after we had seen the leader exiting. */
2847 linux_nat_debug_printf ("Re-adding thread group leader LWP %d.", lwpid
);
2849 lp
= add_lwp (ptid_t (lwpid
, lwpid
, 0));
2852 add_thread (linux_target
, lp
->ptid
);
2855 if (WIFSTOPPED (status
) && !lp
)
2857 linux_nat_debug_printf ("saving LWP %ld status %s in stopped_pids list",
2858 (long) lwpid
, status_to_str (status
));
2859 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2863 /* Make sure we don't report an event for the exit of an LWP not in
2864 our list, i.e. not part of the current process. This can happen
2865 if we detach from a program we originally forked and then it
2867 if (!WIFSTOPPED (status
) && !lp
)
2870 /* This LWP is stopped now. (And if dead, this prevents it from
2871 ever being continued.) */
2874 if (WIFSTOPPED (status
) && lp
->must_set_ptrace_flags
)
2876 inferior
*inf
= find_inferior_pid (linux_target
, lp
->ptid
.pid ());
2877 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2879 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2880 lp
->must_set_ptrace_flags
= 0;
2883 /* Handle GNU/Linux's syscall SIGTRAPs. */
2884 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2886 /* No longer need the sysgood bit. The ptrace event ends up
2887 recorded in lp->waitstatus if we care for it. We can carry
2888 on handling the event like a regular SIGTRAP from here
2890 status
= W_STOPCODE (SIGTRAP
);
2891 if (linux_handle_syscall_trap (lp
, 0))
2896 /* Almost all other ptrace-stops are known to be outside of system
2897 calls, with further exceptions in linux_handle_extended_wait. */
2898 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
2901 /* Handle GNU/Linux's extended waitstatus for trace events. */
2902 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2903 && linux_is_extended_waitstatus (status
))
2905 linux_nat_debug_printf ("Handling extended status 0x%06x", status
);
2907 if (linux_handle_extended_wait (lp
, status
))
2911 /* Check if the thread has exited. */
2912 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2914 if (!report_thread_events
2915 && num_lwps (lp
->ptid
.pid ()) > 1)
2917 linux_nat_debug_printf ("%s exited.",
2918 target_pid_to_str (lp
->ptid
).c_str ());
2920 /* If there is at least one more LWP, then the exit signal
2921 was not the end of the debugged application and should be
2927 /* Note that even if the leader was ptrace-stopped, it can still
2928 exit, if e.g., some other thread brings down the whole
2929 process (calls `exit'). So don't assert that the lwp is
2931 linux_nat_debug_printf ("LWP %ld exited (resumed=%d)",
2932 lp
->ptid
.lwp (), lp
->resumed
);
2934 /* Dead LWP's aren't expected to reported a pending sigstop. */
2937 /* Store the pending event in the waitstatus, because
2938 W_EXITCODE(0,0) == 0. */
2939 store_waitstatus (&lp
->waitstatus
, status
);
2943 /* Make sure we don't report a SIGSTOP that we sent ourselves in
2944 an attempt to stop an LWP. */
2946 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
2950 if (lp
->last_resume_kind
== resume_stop
)
2952 linux_nat_debug_printf ("resume_stop SIGSTOP caught for %s.",
2953 target_pid_to_str (lp
->ptid
).c_str ());
2957 /* This is a delayed SIGSTOP. Filter out the event. */
2959 linux_nat_debug_printf
2960 ("%s %s, 0, 0 (discard delayed SIGSTOP)",
2961 lp
->step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2962 target_pid_to_str (lp
->ptid
).c_str ());
2964 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2965 gdb_assert (lp
->resumed
);
2970 /* Make sure we don't report a SIGINT that we have already displayed
2971 for another thread. */
2972 if (lp
->ignore_sigint
2973 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
2975 linux_nat_debug_printf ("Delayed SIGINT caught for %s.",
2976 target_pid_to_str (lp
->ptid
).c_str ());
2978 /* This is a delayed SIGINT. */
2979 lp
->ignore_sigint
= 0;
2981 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2982 linux_nat_debug_printf ("%s %s, 0, 0 (discard SIGINT)",
2983 lp
->step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2984 target_pid_to_str (lp
->ptid
).c_str ());
2985 gdb_assert (lp
->resumed
);
2987 /* Discard the event. */
2991 /* Don't report signals that GDB isn't interested in, such as
2992 signals that are neither printed nor stopped upon. Stopping all
2993 threads can be a bit time-consuming, so if we want decent
2994 performance with heavily multi-threaded programs, especially when
2995 they're using a high frequency timer, we'd better avoid it if we
2997 if (WIFSTOPPED (status
))
2999 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3001 if (!target_is_non_stop_p ())
3003 /* Only do the below in all-stop, as we currently use SIGSTOP
3004 to implement target_stop (see linux_nat_stop) in
3006 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3008 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3009 forwarded to the entire process group, that is, all LWPs
3010 will receive it - unless they're using CLONE_THREAD to
3011 share signals. Since we only want to report it once, we
3012 mark it as ignored for all LWPs except this one. */
3013 iterate_over_lwps (ptid_t (lp
->ptid
.pid ()), set_ignore_sigint
);
3014 lp
->ignore_sigint
= 0;
3017 maybe_clear_ignore_sigint (lp
);
3020 /* When using hardware single-step, we need to report every signal.
3021 Otherwise, signals in pass_mask may be short-circuited
3022 except signals that might be caused by a breakpoint, or SIGSTOP
3023 if we sent the SIGSTOP and are waiting for it to arrive. */
3025 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
))
3026 && (WSTOPSIG (status
) != SIGSTOP
3027 || !find_thread_ptid (linux_target
, lp
->ptid
)->stop_requested
)
3028 && !linux_wstatus_maybe_breakpoint (status
))
3030 linux_resume_one_lwp (lp
, lp
->step
, signo
);
3031 linux_nat_debug_printf
3032 ("%s %s, %s (preempt 'handle')",
3033 lp
->step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3034 target_pid_to_str (lp
->ptid
).c_str (),
3035 (signo
!= GDB_SIGNAL_0
3036 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
3041 /* An interesting event. */
3043 lp
->status
= status
;
3044 save_stop_reason (lp
);
3048 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3049 their exits until all other threads in the group have exited. */
3052 check_zombie_leaders (void)
3054 for (inferior
*inf
: all_inferiors ())
3056 struct lwp_info
*leader_lp
;
3061 leader_lp
= find_lwp_pid (ptid_t (inf
->pid
));
3062 if (leader_lp
!= NULL
3063 /* Check if there are other threads in the group, as we may
3064 have raced with the inferior simply exiting. */
3065 && num_lwps (inf
->pid
) > 1
3066 && linux_proc_pid_is_zombie (inf
->pid
))
3068 linux_nat_debug_printf ("Thread group leader %d zombie "
3069 "(it exited, or another thread execd).",
3072 /* A leader zombie can mean one of two things:
3074 - It exited, and there's an exit status pending
3075 available, or only the leader exited (not the whole
3076 program). In the latter case, we can't waitpid the
3077 leader's exit status until all other threads are gone.
3079 - There are 3 or more threads in the group, and a thread
3080 other than the leader exec'd. See comments on exec
3081 events at the top of the file. We could try
3082 distinguishing the exit and exec cases, by waiting once
3083 more, and seeing if something comes out, but it doesn't
3084 sound useful. The previous leader _does_ go away, and
3085 we'll re-add the new one once we see the exec event
3086 (which is just the same as what would happen if the
3087 previous leader did exit voluntarily before some other
3090 linux_nat_debug_printf ("Thread group leader %d vanished.", inf
->pid
);
3091 exit_lwp (leader_lp
);
3096 /* Convenience function that is called when the kernel reports an exit
3097 event. This decides whether to report the event to GDB as a
3098 process exit event, a thread exit event, or to suppress the
3102 filter_exit_event (struct lwp_info
*event_child
,
3103 struct target_waitstatus
*ourstatus
)
3105 ptid_t ptid
= event_child
->ptid
;
3107 if (num_lwps (ptid
.pid ()) > 1)
3109 if (report_thread_events
)
3110 ourstatus
->kind
= TARGET_WAITKIND_THREAD_EXITED
;
3112 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3114 exit_lwp (event_child
);
3121 linux_nat_wait_1 (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3122 target_wait_flags target_options
)
3125 enum resume_kind last_resume_kind
;
3126 struct lwp_info
*lp
;
3129 linux_nat_debug_printf ("enter");
3131 /* The first time we get here after starting a new inferior, we may
3132 not have added it to the LWP list yet - this is the earliest
3133 moment at which we know its PID. */
3134 if (ptid
.is_pid () && find_lwp_pid (ptid
) == nullptr)
3136 ptid_t
lwp_ptid (ptid
.pid (), ptid
.pid ());
3138 /* Upgrade the main thread's ptid. */
3139 thread_change_ptid (linux_target
, ptid
, lwp_ptid
);
3140 lp
= add_initial_lwp (lwp_ptid
);
3144 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3145 block_child_signals (&prev_mask
);
3147 /* First check if there is a LWP with a wait status pending. */
3148 lp
= iterate_over_lwps (ptid
, status_callback
);
3151 linux_nat_debug_printf ("Using pending wait status %s for %s.",
3152 status_to_str (lp
->status
),
3153 target_pid_to_str (lp
->ptid
).c_str ());
3156 /* But if we don't find a pending event, we'll have to wait. Always
3157 pull all events out of the kernel. We'll randomly select an
3158 event LWP out of all that have events, to prevent starvation. */
3164 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3167 - If the thread group leader exits while other threads in the
3168 thread group still exist, waitpid(TGID, ...) hangs. That
3169 waitpid won't return an exit status until the other threads
3170 in the group are reaped.
3172 - When a non-leader thread execs, that thread just vanishes
3173 without reporting an exit (so we'd hang if we waited for it
3174 explicitly in that case). The exec event is reported to
3178 lwpid
= my_waitpid (-1, &status
, __WALL
| WNOHANG
);
3180 linux_nat_debug_printf ("waitpid(-1, ...) returned %d, %s",
3182 errno
? safe_strerror (errno
) : "ERRNO-OK");
3186 linux_nat_debug_printf ("waitpid %ld received %s",
3187 (long) lwpid
, status_to_str (status
));
3189 linux_nat_filter_event (lwpid
, status
);
3190 /* Retry until nothing comes out of waitpid. A single
3191 SIGCHLD can indicate more than one child stopped. */
3195 /* Now that we've pulled all events out of the kernel, resume
3196 LWPs that don't have an interesting event to report. */
3197 iterate_over_lwps (minus_one_ptid
,
3198 [] (struct lwp_info
*info
)
3200 return resume_stopped_resumed_lwps (info
, minus_one_ptid
);
3203 /* ... and find an LWP with a status to report to the core, if
3205 lp
= iterate_over_lwps (ptid
, status_callback
);
3209 /* Check for zombie thread group leaders. Those can't be reaped
3210 until all other threads in the thread group are. */
3211 check_zombie_leaders ();
3213 /* If there are no resumed children left, bail. We'd be stuck
3214 forever in the sigsuspend call below otherwise. */
3215 if (iterate_over_lwps (ptid
, resumed_callback
) == NULL
)
3217 linux_nat_debug_printf ("exit (no resumed LWP)");
3219 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3221 restore_child_signals_mask (&prev_mask
);
3222 return minus_one_ptid
;
3225 /* No interesting event to report to the core. */
3227 if (target_options
& TARGET_WNOHANG
)
3229 linux_nat_debug_printf ("exit (ignore)");
3231 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3232 restore_child_signals_mask (&prev_mask
);
3233 return minus_one_ptid
;
3236 /* We shouldn't end up here unless we want to try again. */
3237 gdb_assert (lp
== NULL
);
3239 /* Block until we get an event reported with SIGCHLD. */
3245 status
= lp
->status
;
3248 if (!target_is_non_stop_p ())
3250 /* Now stop all other LWP's ... */
3251 iterate_over_lwps (minus_one_ptid
, stop_callback
);
3253 /* ... and wait until all of them have reported back that
3254 they're no longer running. */
3255 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
);
3258 /* If we're not waiting for a specific LWP, choose an event LWP from
3259 among those that have had events. Giving equal priority to all
3260 LWPs that have had events helps prevent starvation. */
3261 if (ptid
== minus_one_ptid
|| ptid
.is_pid ())
3262 select_event_lwp (ptid
, &lp
, &status
);
3264 gdb_assert (lp
!= NULL
);
3266 /* Now that we've selected our final event LWP, un-adjust its PC if
3267 it was a software breakpoint, and we can't reliably support the
3268 "stopped by software breakpoint" stop reason. */
3269 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
3270 && !USE_SIGTRAP_SIGINFO
)
3272 struct regcache
*regcache
= get_thread_regcache (linux_target
, lp
->ptid
);
3273 struct gdbarch
*gdbarch
= regcache
->arch ();
3274 int decr_pc
= gdbarch_decr_pc_after_break (gdbarch
);
3280 pc
= regcache_read_pc (regcache
);
3281 regcache_write_pc (regcache
, pc
+ decr_pc
);
3285 /* We'll need this to determine whether to report a SIGSTOP as
3286 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3288 last_resume_kind
= lp
->last_resume_kind
;
3290 if (!target_is_non_stop_p ())
3292 /* In all-stop, from the core's perspective, all LWPs are now
3293 stopped until a new resume action is sent over. */
3294 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
);
3298 resume_clear_callback (lp
);
3301 if (linux_target
->low_status_is_event (status
))
3303 linux_nat_debug_printf ("trap ptid is %s.",
3304 target_pid_to_str (lp
->ptid
).c_str ());
3307 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3309 *ourstatus
= lp
->waitstatus
;
3310 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3313 store_waitstatus (ourstatus
, status
);
3315 linux_nat_debug_printf ("exit");
3317 restore_child_signals_mask (&prev_mask
);
3319 if (last_resume_kind
== resume_stop
3320 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3321 && WSTOPSIG (status
) == SIGSTOP
)
3323 /* A thread that has been requested to stop by GDB with
3324 target_stop, and it stopped cleanly, so report as SIG0. The
3325 use of SIGSTOP is an implementation detail. */
3326 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3329 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3330 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3333 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3335 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
)
3336 return filter_exit_event (lp
, ourstatus
);
3341 /* Resume LWPs that are currently stopped without any pending status
3342 to report, but are resumed from the core's perspective. */
3345 resume_stopped_resumed_lwps (struct lwp_info
*lp
, const ptid_t wait_ptid
)
3349 linux_nat_debug_printf ("NOT resuming LWP %s, not stopped",
3350 target_pid_to_str (lp
->ptid
).c_str ());
3352 else if (!lp
->resumed
)
3354 linux_nat_debug_printf ("NOT resuming LWP %s, not resumed",
3355 target_pid_to_str (lp
->ptid
).c_str ());
3357 else if (lwp_status_pending_p (lp
))
3359 linux_nat_debug_printf ("NOT resuming LWP %s, has pending status",
3360 target_pid_to_str (lp
->ptid
).c_str ());
3364 struct regcache
*regcache
= get_thread_regcache (linux_target
, lp
->ptid
);
3365 struct gdbarch
*gdbarch
= regcache
->arch ();
3369 CORE_ADDR pc
= regcache_read_pc (regcache
);
3370 int leave_stopped
= 0;
3372 /* Don't bother if there's a breakpoint at PC that we'd hit
3373 immediately, and we're not waiting for this LWP. */
3374 if (!lp
->ptid
.matches (wait_ptid
))
3376 if (breakpoint_inserted_here_p (regcache
->aspace (), pc
))
3382 linux_nat_debug_printf
3383 ("resuming stopped-resumed LWP %s at %s: step=%d",
3384 target_pid_to_str (lp
->ptid
).c_str (), paddress (gdbarch
, pc
),
3387 linux_resume_one_lwp_throw (lp
, lp
->step
, GDB_SIGNAL_0
);
3390 catch (const gdb_exception_error
&ex
)
3392 if (!check_ptrace_stopped_lwp_gone (lp
))
3401 linux_nat_target::wait (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3402 target_wait_flags target_options
)
3406 linux_nat_debug_printf ("[%s], [%s]", target_pid_to_str (ptid
).c_str (),
3407 target_options_to_string (target_options
).c_str ());
3409 /* Flush the async file first. */
3410 if (target_is_async_p ())
3411 async_file_flush ();
3413 /* Resume LWPs that are currently stopped without any pending status
3414 to report, but are resumed from the core's perspective. LWPs get
3415 in this state if we find them stopping at a time we're not
3416 interested in reporting the event (target_wait on a
3417 specific_process, for example, see linux_nat_wait_1), and
3418 meanwhile the event became uninteresting. Don't bother resuming
3419 LWPs we're not going to wait for if they'd stop immediately. */
3420 if (target_is_non_stop_p ())
3421 iterate_over_lwps (minus_one_ptid
,
3422 [=] (struct lwp_info
*info
)
3424 return resume_stopped_resumed_lwps (info
, ptid
);
3427 event_ptid
= linux_nat_wait_1 (ptid
, ourstatus
, target_options
);
3429 /* If we requested any event, and something came out, assume there
3430 may be more. If we requested a specific lwp or process, also
3431 assume there may be more. */
3432 if (target_is_async_p ()
3433 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3434 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3435 || ptid
!= minus_one_ptid
))
3444 kill_one_lwp (pid_t pid
)
3446 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3449 kill_lwp (pid
, SIGKILL
);
3451 if (debug_linux_nat
)
3453 int save_errno
= errno
;
3455 linux_nat_debug_printf
3456 ("kill (SIGKILL) %ld, 0, 0 (%s)", (long) pid
,
3457 save_errno
!= 0 ? safe_strerror (save_errno
) : "OK");
3460 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3463 ptrace (PTRACE_KILL
, pid
, 0, 0);
3464 if (debug_linux_nat
)
3466 int save_errno
= errno
;
3468 linux_nat_debug_printf
3469 ("PTRACE_KILL %ld, 0, 0 (%s)", (long) pid
,
3470 save_errno
? safe_strerror (save_errno
) : "OK");
3474 /* Wait for an LWP to die. */
3477 kill_wait_one_lwp (pid_t pid
)
3481 /* We must make sure that there are no pending events (delayed
3482 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3483 program doesn't interfere with any following debugging session. */
3487 res
= my_waitpid (pid
, NULL
, __WALL
);
3488 if (res
!= (pid_t
) -1)
3490 linux_nat_debug_printf ("wait %ld received unknown.", (long) pid
);
3492 /* The Linux kernel sometimes fails to kill a thread
3493 completely after PTRACE_KILL; that goes from the stop
3494 point in do_fork out to the one in get_signal_to_deliver
3495 and waits again. So kill it again. */
3501 gdb_assert (res
== -1 && errno
== ECHILD
);
3504 /* Callback for iterate_over_lwps. */
3507 kill_callback (struct lwp_info
*lp
)
3509 kill_one_lwp (lp
->ptid
.lwp ());
3513 /* Callback for iterate_over_lwps. */
3516 kill_wait_callback (struct lwp_info
*lp
)
3518 kill_wait_one_lwp (lp
->ptid
.lwp ());
3522 /* Kill the fork children of any threads of inferior INF that are
3523 stopped at a fork event. */
3526 kill_unfollowed_fork_children (struct inferior
*inf
)
3528 for (thread_info
*thread
: inf
->non_exited_threads ())
3530 struct target_waitstatus
*ws
= &thread
->pending_follow
;
3532 if (ws
->kind
== TARGET_WAITKIND_FORKED
3533 || ws
->kind
== TARGET_WAITKIND_VFORKED
)
3535 ptid_t child_ptid
= ws
->value
.related_pid
;
3536 int child_pid
= child_ptid
.pid ();
3537 int child_lwp
= child_ptid
.lwp ();
3539 kill_one_lwp (child_lwp
);
3540 kill_wait_one_lwp (child_lwp
);
3542 /* Let the arch-specific native code know this process is
3544 linux_target
->low_forget_process (child_pid
);
3550 linux_nat_target::kill ()
3552 /* If we're stopped while forking and we haven't followed yet,
3553 kill the other task. We need to do this first because the
3554 parent will be sleeping if this is a vfork. */
3555 kill_unfollowed_fork_children (current_inferior ());
3557 if (forks_exist_p ())
3558 linux_fork_killall ();
3561 ptid_t ptid
= ptid_t (inferior_ptid
.pid ());
3563 /* Stop all threads before killing them, since ptrace requires
3564 that the thread is stopped to successfully PTRACE_KILL. */
3565 iterate_over_lwps (ptid
, stop_callback
);
3566 /* ... and wait until all of them have reported back that
3567 they're no longer running. */
3568 iterate_over_lwps (ptid
, stop_wait_callback
);
3570 /* Kill all LWP's ... */
3571 iterate_over_lwps (ptid
, kill_callback
);
3573 /* ... and wait until we've flushed all events. */
3574 iterate_over_lwps (ptid
, kill_wait_callback
);
3577 target_mourn_inferior (inferior_ptid
);
3581 linux_nat_target::mourn_inferior ()
3583 int pid
= inferior_ptid
.pid ();
3585 purge_lwp_list (pid
);
3587 if (! forks_exist_p ())
3588 /* Normal case, no other forks available. */
3589 inf_ptrace_target::mourn_inferior ();
3591 /* Multi-fork case. The current inferior_ptid has exited, but
3592 there are other viable forks to debug. Delete the exiting
3593 one and context-switch to the first available. */
3594 linux_fork_mourn_inferior ();
3596 /* Let the arch-specific native code know this process is gone. */
3597 linux_target
->low_forget_process (pid
);
3600 /* Convert a native/host siginfo object, into/from the siginfo in the
3601 layout of the inferiors' architecture. */
3604 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3606 /* If the low target didn't do anything, then just do a straight
3608 if (!linux_target
->low_siginfo_fixup (siginfo
, inf_siginfo
, direction
))
3611 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3613 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3617 static enum target_xfer_status
3618 linux_xfer_siginfo (enum target_object object
,
3619 const char *annex
, gdb_byte
*readbuf
,
3620 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3621 ULONGEST
*xfered_len
)
3625 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3627 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3628 gdb_assert (readbuf
|| writebuf
);
3630 pid
= inferior_ptid
.lwp ();
3632 pid
= inferior_ptid
.pid ();
3634 if (offset
> sizeof (siginfo
))
3635 return TARGET_XFER_E_IO
;
3638 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3640 return TARGET_XFER_E_IO
;
3642 /* When GDB is built as a 64-bit application, ptrace writes into
3643 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3644 inferior with a 64-bit GDB should look the same as debugging it
3645 with a 32-bit GDB, we need to convert it. GDB core always sees
3646 the converted layout, so any read/write will have to be done
3648 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3650 if (offset
+ len
> sizeof (siginfo
))
3651 len
= sizeof (siginfo
) - offset
;
3653 if (readbuf
!= NULL
)
3654 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3657 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3659 /* Convert back to ptrace layout before flushing it out. */
3660 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3663 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3665 return TARGET_XFER_E_IO
;
3669 return TARGET_XFER_OK
;
3672 static enum target_xfer_status
3673 linux_nat_xfer_osdata (enum target_object object
,
3674 const char *annex
, gdb_byte
*readbuf
,
3675 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3676 ULONGEST
*xfered_len
);
3678 static enum target_xfer_status
3679 linux_proc_xfer_partial (enum target_object object
,
3680 const char *annex
, gdb_byte
*readbuf
,
3681 const gdb_byte
*writebuf
,
3682 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
);
3684 enum target_xfer_status
3685 linux_nat_target::xfer_partial (enum target_object object
,
3686 const char *annex
, gdb_byte
*readbuf
,
3687 const gdb_byte
*writebuf
,
3688 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3690 enum target_xfer_status xfer
;
3692 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3693 return linux_xfer_siginfo (object
, annex
, readbuf
, writebuf
,
3694 offset
, len
, xfered_len
);
3696 /* The target is connected but no live inferior is selected. Pass
3697 this request down to a lower stratum (e.g., the executable
3699 if (object
== TARGET_OBJECT_MEMORY
&& inferior_ptid
== null_ptid
)
3700 return TARGET_XFER_EOF
;
3702 if (object
== TARGET_OBJECT_AUXV
)
3703 return memory_xfer_auxv (this, object
, annex
, readbuf
, writebuf
,
3704 offset
, len
, xfered_len
);
3706 if (object
== TARGET_OBJECT_OSDATA
)
3707 return linux_nat_xfer_osdata (object
, annex
, readbuf
, writebuf
,
3708 offset
, len
, xfered_len
);
3710 /* GDB calculates all addresses in the largest possible address
3712 The address width must be masked before its final use - either by
3713 linux_proc_xfer_partial or inf_ptrace_target::xfer_partial.
3715 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
3717 if (object
== TARGET_OBJECT_MEMORY
)
3719 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
3721 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
3722 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
3725 xfer
= linux_proc_xfer_partial (object
, annex
, readbuf
, writebuf
,
3726 offset
, len
, xfered_len
);
3727 if (xfer
!= TARGET_XFER_EOF
)
3730 return inf_ptrace_target::xfer_partial (object
, annex
, readbuf
, writebuf
,
3731 offset
, len
, xfered_len
);
3735 linux_nat_target::thread_alive (ptid_t ptid
)
3737 /* As long as a PTID is in lwp list, consider it alive. */
3738 return find_lwp_pid (ptid
) != NULL
;
3741 /* Implement the to_update_thread_list target method for this
3745 linux_nat_target::update_thread_list ()
3747 struct lwp_info
*lwp
;
3749 /* We add/delete threads from the list as clone/exit events are
3750 processed, so just try deleting exited threads still in the
3752 delete_exited_threads ();
3754 /* Update the processor core that each lwp/thread was last seen
3758 /* Avoid accessing /proc if the thread hasn't run since we last
3759 time we fetched the thread's core. Accessing /proc becomes
3760 noticeably expensive when we have thousands of LWPs. */
3761 if (lwp
->core
== -1)
3762 lwp
->core
= linux_common_core_of_thread (lwp
->ptid
);
3767 linux_nat_target::pid_to_str (ptid_t ptid
)
3770 && (ptid
.pid () != ptid
.lwp ()
3771 || num_lwps (ptid
.pid ()) > 1))
3772 return string_printf ("LWP %ld", ptid
.lwp ());
3774 return normal_pid_to_str (ptid
);
3778 linux_nat_target::thread_name (struct thread_info
*thr
)
3780 return linux_proc_tid_get_name (thr
->ptid
);
3783 /* Accepts an integer PID; Returns a string representing a file that
3784 can be opened to get the symbols for the child process. */
3787 linux_nat_target::pid_to_exec_file (int pid
)
3789 return linux_proc_pid_to_exec_file (pid
);
3792 /* Implement the to_xfer_partial target method using /proc/<pid>/mem.
3793 Because we can use a single read/write call, this can be much more
3794 efficient than banging away at PTRACE_PEEKTEXT. */
3796 static enum target_xfer_status
3797 linux_proc_xfer_partial (enum target_object object
,
3798 const char *annex
, gdb_byte
*readbuf
,
3799 const gdb_byte
*writebuf
,
3800 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
3806 if (object
!= TARGET_OBJECT_MEMORY
)
3807 return TARGET_XFER_EOF
;
3809 /* Don't bother for one word. */
3810 if (len
< 3 * sizeof (long))
3811 return TARGET_XFER_EOF
;
3813 /* We could keep this file open and cache it - possibly one per
3814 thread. That requires some juggling, but is even faster. */
3815 xsnprintf (filename
, sizeof filename
, "/proc/%ld/mem",
3816 inferior_ptid
.lwp ());
3817 fd
= gdb_open_cloexec (filename
, ((readbuf
? O_RDONLY
: O_WRONLY
)
3820 return TARGET_XFER_EOF
;
3822 /* Use pread64/pwrite64 if available, since they save a syscall and can
3823 handle 64-bit offsets even on 32-bit platforms (for instance, SPARC
3824 debugging a SPARC64 application). */
3826 ret
= (readbuf
? pread64 (fd
, readbuf
, len
, offset
)
3827 : pwrite64 (fd
, writebuf
, len
, offset
));
3829 ret
= lseek (fd
, offset
, SEEK_SET
);
3831 ret
= (readbuf
? read (fd
, readbuf
, len
)
3832 : write (fd
, writebuf
, len
));
3837 if (ret
== -1 || ret
== 0)
3838 return TARGET_XFER_EOF
;
3842 return TARGET_XFER_OK
;
3847 /* Parse LINE as a signal set and add its set bits to SIGS. */
3850 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
3852 int len
= strlen (line
) - 1;
3856 if (line
[len
] != '\n')
3857 error (_("Could not parse signal set: %s"), line
);
3865 if (*p
>= '0' && *p
<= '9')
3867 else if (*p
>= 'a' && *p
<= 'f')
3868 digit
= *p
- 'a' + 10;
3870 error (_("Could not parse signal set: %s"), line
);
3875 sigaddset (sigs
, signum
+ 1);
3877 sigaddset (sigs
, signum
+ 2);
3879 sigaddset (sigs
, signum
+ 3);
3881 sigaddset (sigs
, signum
+ 4);
3887 /* Find process PID's pending signals from /proc/pid/status and set
3891 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
3892 sigset_t
*blocked
, sigset_t
*ignored
)
3894 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
3896 sigemptyset (pending
);
3897 sigemptyset (blocked
);
3898 sigemptyset (ignored
);
3899 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
3900 gdb_file_up procfile
= gdb_fopen_cloexec (fname
, "r");
3901 if (procfile
== NULL
)
3902 error (_("Could not open %s"), fname
);
3904 while (fgets (buffer
, PATH_MAX
, procfile
.get ()) != NULL
)
3906 /* Normal queued signals are on the SigPnd line in the status
3907 file. However, 2.6 kernels also have a "shared" pending
3908 queue for delivering signals to a thread group, so check for
3911 Unfortunately some Red Hat kernels include the shared pending
3912 queue but not the ShdPnd status field. */
3914 if (startswith (buffer
, "SigPnd:\t"))
3915 add_line_to_sigset (buffer
+ 8, pending
);
3916 else if (startswith (buffer
, "ShdPnd:\t"))
3917 add_line_to_sigset (buffer
+ 8, pending
);
3918 else if (startswith (buffer
, "SigBlk:\t"))
3919 add_line_to_sigset (buffer
+ 8, blocked
);
3920 else if (startswith (buffer
, "SigIgn:\t"))
3921 add_line_to_sigset (buffer
+ 8, ignored
);
3925 static enum target_xfer_status
3926 linux_nat_xfer_osdata (enum target_object object
,
3927 const char *annex
, gdb_byte
*readbuf
,
3928 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3929 ULONGEST
*xfered_len
)
3931 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
3933 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
3934 if (*xfered_len
== 0)
3935 return TARGET_XFER_EOF
;
3937 return TARGET_XFER_OK
;
3940 std::vector
<static_tracepoint_marker
>
3941 linux_nat_target::static_tracepoint_markers_by_strid (const char *strid
)
3943 char s
[IPA_CMD_BUF_SIZE
];
3944 int pid
= inferior_ptid
.pid ();
3945 std::vector
<static_tracepoint_marker
> markers
;
3947 ptid_t ptid
= ptid_t (pid
, 0, 0);
3948 static_tracepoint_marker marker
;
3953 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
3954 s
[sizeof ("qTfSTM")] = 0;
3956 agent_run_command (pid
, s
, strlen (s
) + 1);
3959 SCOPE_EXIT
{ target_continue_no_signal (ptid
); };
3965 parse_static_tracepoint_marker_definition (p
, &p
, &marker
);
3967 if (strid
== NULL
|| marker
.str_id
== strid
)
3968 markers
.push_back (std::move (marker
));
3970 while (*p
++ == ','); /* comma-separated list */
3972 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
3973 s
[sizeof ("qTsSTM")] = 0;
3974 agent_run_command (pid
, s
, strlen (s
) + 1);
3981 /* target_is_async_p implementation. */
3984 linux_nat_target::is_async_p ()
3986 return linux_is_async_p ();
3989 /* target_can_async_p implementation. */
3992 linux_nat_target::can_async_p ()
3994 /* We're always async, unless the user explicitly prevented it with the
3995 "maint set target-async" command. */
3996 return target_async_permitted
;
4000 linux_nat_target::supports_non_stop ()
4005 /* to_always_non_stop_p implementation. */
4008 linux_nat_target::always_non_stop_p ()
4014 linux_nat_target::supports_multi_process ()
4020 linux_nat_target::supports_disable_randomization ()
4022 #ifdef HAVE_PERSONALITY
4029 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4030 so we notice when any child changes state, and notify the
4031 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4032 above to wait for the arrival of a SIGCHLD. */
4035 sigchld_handler (int signo
)
4037 int old_errno
= errno
;
4039 if (debug_linux_nat
)
4040 gdb_stdlog
->write_async_safe ("sigchld\n", sizeof ("sigchld\n") - 1);
4042 if (signo
== SIGCHLD
4043 && linux_nat_event_pipe
[0] != -1)
4044 async_file_mark (); /* Let the event loop know that there are
4045 events to handle. */
4050 /* Callback registered with the target events file descriptor. */
4053 handle_target_event (int error
, gdb_client_data client_data
)
4055 inferior_event_handler (INF_REG_EVENT
);
4058 /* Create/destroy the target events pipe. Returns previous state. */
4061 linux_async_pipe (int enable
)
4063 int previous
= linux_is_async_p ();
4065 if (previous
!= enable
)
4069 /* Block child signals while we create/destroy the pipe, as
4070 their handler writes to it. */
4071 block_child_signals (&prev_mask
);
4075 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4076 internal_error (__FILE__
, __LINE__
,
4077 "creating event pipe failed.");
4079 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4080 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4084 close (linux_nat_event_pipe
[0]);
4085 close (linux_nat_event_pipe
[1]);
4086 linux_nat_event_pipe
[0] = -1;
4087 linux_nat_event_pipe
[1] = -1;
4090 restore_child_signals_mask (&prev_mask
);
4097 linux_nat_target::async_wait_fd ()
4099 return linux_nat_event_pipe
[0];
4102 /* target_async implementation. */
4105 linux_nat_target::async (int enable
)
4109 if (!linux_async_pipe (1))
4111 add_file_handler (linux_nat_event_pipe
[0],
4112 handle_target_event
, NULL
,
4114 /* There may be pending events to handle. Tell the event loop
4121 delete_file_handler (linux_nat_event_pipe
[0]);
4122 linux_async_pipe (0);
4127 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4131 linux_nat_stop_lwp (struct lwp_info
*lwp
)
4135 linux_nat_debug_printf ("running -> suspending %s",
4136 target_pid_to_str (lwp
->ptid
).c_str ());
4139 if (lwp
->last_resume_kind
== resume_stop
)
4141 linux_nat_debug_printf ("already stopping LWP %ld at GDB's request",
4146 stop_callback (lwp
);
4147 lwp
->last_resume_kind
= resume_stop
;
4151 /* Already known to be stopped; do nothing. */
4153 if (debug_linux_nat
)
4155 if (find_thread_ptid (linux_target
, lwp
->ptid
)->stop_requested
)
4156 linux_nat_debug_printf ("already stopped/stop_requested %s",
4157 target_pid_to_str (lwp
->ptid
).c_str ());
4159 linux_nat_debug_printf ("already stopped/no stop_requested yet %s",
4160 target_pid_to_str (lwp
->ptid
).c_str ());
4167 linux_nat_target::stop (ptid_t ptid
)
4169 iterate_over_lwps (ptid
, linux_nat_stop_lwp
);
4173 linux_nat_target::close ()
4175 /* Unregister from the event loop. */
4179 inf_ptrace_target::close ();
4182 /* When requests are passed down from the linux-nat layer to the
4183 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4184 used. The address space pointer is stored in the inferior object,
4185 but the common code that is passed such ptid can't tell whether
4186 lwpid is a "main" process id or not (it assumes so). We reverse
4187 look up the "main" process id from the lwp here. */
4189 struct address_space
*
4190 linux_nat_target::thread_address_space (ptid_t ptid
)
4192 struct lwp_info
*lwp
;
4193 struct inferior
*inf
;
4196 if (ptid
.lwp () == 0)
4198 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4200 lwp
= find_lwp_pid (ptid
);
4201 pid
= lwp
->ptid
.pid ();
4205 /* A (pid,lwpid,0) ptid. */
4209 inf
= find_inferior_pid (this, pid
);
4210 gdb_assert (inf
!= NULL
);
4214 /* Return the cached value of the processor core for thread PTID. */
4217 linux_nat_target::core_of_thread (ptid_t ptid
)
4219 struct lwp_info
*info
= find_lwp_pid (ptid
);
4226 /* Implementation of to_filesystem_is_local. */
4229 linux_nat_target::filesystem_is_local ()
4231 struct inferior
*inf
= current_inferior ();
4233 if (inf
->fake_pid_p
|| inf
->pid
== 0)
4236 return linux_ns_same (inf
->pid
, LINUX_NS_MNT
);
4239 /* Convert the INF argument passed to a to_fileio_* method
4240 to a process ID suitable for passing to its corresponding
4241 linux_mntns_* function. If INF is non-NULL then the
4242 caller is requesting the filesystem seen by INF. If INF
4243 is NULL then the caller is requesting the filesystem seen
4244 by the GDB. We fall back to GDB's filesystem in the case
4245 that INF is non-NULL but its PID is unknown. */
4248 linux_nat_fileio_pid_of (struct inferior
*inf
)
4250 if (inf
== NULL
|| inf
->fake_pid_p
|| inf
->pid
== 0)
4256 /* Implementation of to_fileio_open. */
4259 linux_nat_target::fileio_open (struct inferior
*inf
, const char *filename
,
4260 int flags
, int mode
, int warn_if_slow
,
4267 if (fileio_to_host_openflags (flags
, &nat_flags
) == -1
4268 || fileio_to_host_mode (mode
, &nat_mode
) == -1)
4270 *target_errno
= FILEIO_EINVAL
;
4274 fd
= linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf
),
4275 filename
, nat_flags
, nat_mode
);
4277 *target_errno
= host_to_fileio_error (errno
);
4282 /* Implementation of to_fileio_readlink. */
4284 gdb::optional
<std::string
>
4285 linux_nat_target::fileio_readlink (struct inferior
*inf
, const char *filename
,
4291 len
= linux_mntns_readlink (linux_nat_fileio_pid_of (inf
),
4292 filename
, buf
, sizeof (buf
));
4295 *target_errno
= host_to_fileio_error (errno
);
4299 return std::string (buf
, len
);
4302 /* Implementation of to_fileio_unlink. */
4305 linux_nat_target::fileio_unlink (struct inferior
*inf
, const char *filename
,
4310 ret
= linux_mntns_unlink (linux_nat_fileio_pid_of (inf
),
4313 *target_errno
= host_to_fileio_error (errno
);
4318 /* Implementation of the to_thread_events method. */
4321 linux_nat_target::thread_events (int enable
)
4323 report_thread_events
= enable
;
4326 linux_nat_target::linux_nat_target ()
4328 /* We don't change the stratum; this target will sit at
4329 process_stratum and thread_db will set at thread_stratum. This
4330 is a little strange, since this is a multi-threaded-capable
4331 target, but we want to be on the stack below thread_db, and we
4332 also want to be used for single-threaded processes. */
4335 /* See linux-nat.h. */
4338 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4347 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4350 memset (siginfo
, 0, sizeof (*siginfo
));
4356 /* See nat/linux-nat.h. */
4359 current_lwp_ptid (void)
4361 gdb_assert (inferior_ptid
.lwp_p ());
4362 return inferior_ptid
;
4365 void _initialize_linux_nat ();
4367 _initialize_linux_nat ()
4369 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4370 &debug_linux_nat
, _("\
4371 Set debugging of GNU/Linux lwp module."), _("\
4372 Show debugging of GNU/Linux lwp module."), _("\
4373 Enables printf debugging output."),
4375 show_debug_linux_nat
,
4376 &setdebuglist
, &showdebuglist
);
4378 add_setshow_boolean_cmd ("linux-namespaces", class_maintenance
,
4379 &debug_linux_namespaces
, _("\
4380 Set debugging of GNU/Linux namespaces module."), _("\
4381 Show debugging of GNU/Linux namespaces module."), _("\
4382 Enables printf debugging output."),
4385 &setdebuglist
, &showdebuglist
);
4387 /* Install a SIGCHLD handler. */
4388 sigchld_action
.sa_handler
= sigchld_handler
;
4389 sigemptyset (&sigchld_action
.sa_mask
);
4390 sigchld_action
.sa_flags
= SA_RESTART
;
4392 /* Make it the default. */
4393 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4395 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4396 gdb_sigmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4397 sigdelset (&suspend_mask
, SIGCHLD
);
4399 sigemptyset (&blocked_mask
);
4401 lwp_lwpid_htab_create ();
4405 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4406 the GNU/Linux Threads library and therefore doesn't really belong
4409 /* Return the set of signals used by the threads library in *SET. */
4412 lin_thread_get_thread_signals (sigset_t
*set
)
4416 /* NPTL reserves the first two RT signals, but does not provide any
4417 way for the debugger to query the signal numbers - fortunately
4418 they don't change. */
4419 sigaddset (set
, __SIGRTMIN
);
4420 sigaddset (set
, __SIGRTMIN
+ 1);