1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2019 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
26 #include "common/gdb_wait.h"
28 #include <sys/syscall.h>
29 #include "nat/gdb_ptrace.h"
30 #include "linux-nat.h"
31 #include "nat/linux-ptrace.h"
32 #include "nat/linux-procfs.h"
33 #include "nat/linux-personality.h"
34 #include "linux-fork.h"
35 #include "gdbthread.h"
39 #include "inf-child.h"
40 #include "inf-ptrace.h"
42 #include <sys/procfs.h> /* for elf_gregset etc. */
43 #include "elf-bfd.h" /* for elfcore_write_* */
44 #include "gregset.h" /* for gregset */
45 #include "gdbcore.h" /* for get_exec_file */
46 #include <ctype.h> /* for isdigit */
47 #include <sys/stat.h> /* for struct stat */
48 #include <fcntl.h> /* for O_RDONLY */
50 #include "event-loop.h"
51 #include "event-top.h"
53 #include <sys/types.h>
55 #include "xml-support.h"
58 #include "nat/linux-osdata.h"
59 #include "linux-tdep.h"
61 #include "common/agent.h"
62 #include "tracepoint.h"
63 #include "common/buffer.h"
64 #include "target-descriptions.h"
65 #include "common/filestuff.h"
67 #include "nat/linux-namespaces.h"
68 #include "common/fileio.h"
69 #include "common/scope-exit.h"
72 #define SPUFS_MAGIC 0x23c9b64e
75 /* This comment documents high-level logic of this file.
77 Waiting for events in sync mode
78 ===============================
80 When waiting for an event in a specific thread, we just use waitpid,
81 passing the specific pid, and not passing WNOHANG.
83 When waiting for an event in all threads, waitpid is not quite good:
85 - If the thread group leader exits while other threads in the thread
86 group still exist, waitpid(TGID, ...) hangs. That waitpid won't
87 return an exit status until the other threads in the group are
90 - When a non-leader thread execs, that thread just vanishes without
91 reporting an exit (so we'd hang if we waited for it explicitly in
92 that case). The exec event is instead reported to the TGID pid.
94 The solution is to always use -1 and WNOHANG, together with
97 First, we use non-blocking waitpid to check for events. If nothing is
98 found, we use sigsuspend to wait for SIGCHLD. When SIGCHLD arrives,
99 it means something happened to a child process. As soon as we know
100 there's an event, we get back to calling nonblocking waitpid.
102 Note that SIGCHLD should be blocked between waitpid and sigsuspend
103 calls, so that we don't miss a signal. If SIGCHLD arrives in between,
104 when it's blocked, the signal becomes pending and sigsuspend
105 immediately notices it and returns.
107 Waiting for events in async mode (TARGET_WNOHANG)
108 =================================================
110 In async mode, GDB should always be ready to handle both user input
111 and target events, so neither blocking waitpid nor sigsuspend are
112 viable options. Instead, we should asynchronously notify the GDB main
113 event loop whenever there's an unprocessed event from the target. We
114 detect asynchronous target events by handling SIGCHLD signals. To
115 notify the event loop about target events, the self-pipe trick is used
116 --- a pipe is registered as waitable event source in the event loop,
117 the event loop select/poll's on the read end of this pipe (as well on
118 other event sources, e.g., stdin), and the SIGCHLD handler writes a
119 byte to this pipe. This is more portable than relying on
120 pselect/ppoll, since on kernels that lack those syscalls, libc
121 emulates them with select/poll+sigprocmask, and that is racy
122 (a.k.a. plain broken).
124 Obviously, if we fail to notify the event loop if there's a target
125 event, it's bad. OTOH, if we notify the event loop when there's no
126 event from the target, linux_nat_wait will detect that there's no real
127 event to report, and return event of type TARGET_WAITKIND_IGNORE.
128 This is mostly harmless, but it will waste time and is better avoided.
130 The main design point is that every time GDB is outside linux-nat.c,
131 we have a SIGCHLD handler installed that is called when something
132 happens to the target and notifies the GDB event loop. Whenever GDB
133 core decides to handle the event, and calls into linux-nat.c, we
134 process things as in sync mode, except that the we never block in
137 While processing an event, we may end up momentarily blocked in
138 waitpid calls. Those waitpid calls, while blocking, are guarantied to
139 return quickly. E.g., in all-stop mode, before reporting to the core
140 that an LWP hit a breakpoint, all LWPs are stopped by sending them
141 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
142 Note that this is different from blocking indefinitely waiting for the
143 next event --- here, we're already handling an event.
148 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
149 signal is not entirely significant; we just need for a signal to be delivered,
150 so that we can intercept it. SIGSTOP's advantage is that it can not be
151 blocked. A disadvantage is that it is not a real-time signal, so it can only
152 be queued once; we do not keep track of other sources of SIGSTOP.
154 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
155 use them, because they have special behavior when the signal is generated -
156 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
157 kills the entire thread group.
159 A delivered SIGSTOP would stop the entire thread group, not just the thread we
160 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
161 cancel it (by PTRACE_CONT without passing SIGSTOP).
163 We could use a real-time signal instead. This would solve those problems; we
164 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
165 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
166 generates it, and there are races with trying to find a signal that is not
172 The case of a thread group (process) with 3 or more threads, and a
173 thread other than the leader execs is worth detailing:
175 On an exec, the Linux kernel destroys all threads except the execing
176 one in the thread group, and resets the execing thread's tid to the
177 tgid. No exit notification is sent for the execing thread -- from the
178 ptracer's perspective, it appears as though the execing thread just
179 vanishes. Until we reap all other threads except the leader and the
180 execing thread, the leader will be zombie, and the execing thread will
181 be in `D (disc sleep)' state. As soon as all other threads are
182 reaped, the execing thread changes its tid to the tgid, and the
183 previous (zombie) leader vanishes, giving place to the "new"
187 #define O_LARGEFILE 0
190 struct linux_nat_target
*linux_target
;
192 /* Does the current host support PTRACE_GETREGSET? */
193 enum tribool have_ptrace_getregset
= TRIBOOL_UNKNOWN
;
195 static unsigned int debug_linux_nat
;
197 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
198 struct cmd_list_element
*c
, const char *value
)
200 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
204 struct simple_pid_list
208 struct simple_pid_list
*next
;
210 struct simple_pid_list
*stopped_pids
;
212 /* Whether target_thread_events is in effect. */
213 static int report_thread_events
;
215 /* Async mode support. */
217 /* The read/write ends of the pipe registered as waitable file in the
219 static int linux_nat_event_pipe
[2] = { -1, -1 };
221 /* True if we're currently in async mode. */
222 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
224 /* Flush the event pipe. */
227 async_file_flush (void)
234 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
236 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
239 /* Put something (anything, doesn't matter what, or how much) in event
240 pipe, so that the select/poll in the event-loop realizes we have
241 something to process. */
244 async_file_mark (void)
248 /* It doesn't really matter what the pipe contains, as long we end
249 up with something in it. Might as well flush the previous
255 ret
= write (linux_nat_event_pipe
[1], "+", 1);
257 while (ret
== -1 && errno
== EINTR
);
259 /* Ignore EAGAIN. If the pipe is full, the event loop will already
260 be awakened anyway. */
263 static int kill_lwp (int lwpid
, int signo
);
265 static int stop_callback (struct lwp_info
*lp
);
267 static void block_child_signals (sigset_t
*prev_mask
);
268 static void restore_child_signals_mask (sigset_t
*prev_mask
);
271 static struct lwp_info
*add_lwp (ptid_t ptid
);
272 static void purge_lwp_list (int pid
);
273 static void delete_lwp (ptid_t ptid
);
274 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
276 static int lwp_status_pending_p (struct lwp_info
*lp
);
278 static void save_stop_reason (struct lwp_info
*lp
);
283 /* See nat/linux-nat.h. */
286 ptid_of_lwp (struct lwp_info
*lwp
)
291 /* See nat/linux-nat.h. */
294 lwp_set_arch_private_info (struct lwp_info
*lwp
,
295 struct arch_lwp_info
*info
)
297 lwp
->arch_private
= info
;
300 /* See nat/linux-nat.h. */
302 struct arch_lwp_info
*
303 lwp_arch_private_info (struct lwp_info
*lwp
)
305 return lwp
->arch_private
;
308 /* See nat/linux-nat.h. */
311 lwp_is_stopped (struct lwp_info
*lwp
)
316 /* See nat/linux-nat.h. */
318 enum target_stop_reason
319 lwp_stop_reason (struct lwp_info
*lwp
)
321 return lwp
->stop_reason
;
324 /* See nat/linux-nat.h. */
327 lwp_is_stepping (struct lwp_info
*lwp
)
333 /* Trivial list manipulation functions to keep track of a list of
334 new stopped processes. */
336 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
338 struct simple_pid_list
*new_pid
= XNEW (struct simple_pid_list
);
341 new_pid
->status
= status
;
342 new_pid
->next
= *listp
;
347 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
349 struct simple_pid_list
**p
;
351 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
352 if ((*p
)->pid
== pid
)
354 struct simple_pid_list
*next
= (*p
)->next
;
356 *statusp
= (*p
)->status
;
364 /* Return the ptrace options that we want to try to enable. */
367 linux_nat_ptrace_options (int attached
)
372 options
|= PTRACE_O_EXITKILL
;
374 options
|= (PTRACE_O_TRACESYSGOOD
375 | PTRACE_O_TRACEVFORKDONE
376 | PTRACE_O_TRACEVFORK
378 | PTRACE_O_TRACEEXEC
);
383 /* Initialize ptrace and procfs warnings and check for supported
384 ptrace features given PID.
386 ATTACHED should be nonzero iff we attached to the inferior. */
389 linux_init_ptrace_procfs (pid_t pid
, int attached
)
391 int options
= linux_nat_ptrace_options (attached
);
393 linux_enable_event_reporting (pid
, options
);
394 linux_ptrace_init_warnings ();
395 linux_proc_init_warnings ();
398 linux_nat_target::~linux_nat_target ()
402 linux_nat_target::post_attach (int pid
)
404 linux_init_ptrace_procfs (pid
, 1);
408 linux_nat_target::post_startup_inferior (ptid_t ptid
)
410 linux_init_ptrace_procfs (ptid
.pid (), 0);
413 /* Return the number of known LWPs in the tgid given by PID. */
421 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
422 if (lp
->ptid
.pid () == pid
)
428 /* Deleter for lwp_info unique_ptr specialisation. */
432 void operator() (struct lwp_info
*lwp
) const
434 delete_lwp (lwp
->ptid
);
438 /* A unique_ptr specialisation for lwp_info. */
440 typedef std::unique_ptr
<struct lwp_info
, lwp_deleter
> lwp_info_up
;
442 /* Target hook for follow_fork. On entry inferior_ptid must be the
443 ptid of the followed inferior. At return, inferior_ptid will be
447 linux_nat_target::follow_fork (int follow_child
, int detach_fork
)
451 struct lwp_info
*child_lp
= NULL
;
453 ptid_t parent_ptid
, child_ptid
;
454 int parent_pid
, child_pid
;
456 has_vforked
= (inferior_thread ()->pending_follow
.kind
457 == TARGET_WAITKIND_VFORKED
);
458 parent_ptid
= inferior_ptid
;
459 child_ptid
= inferior_thread ()->pending_follow
.value
.related_pid
;
460 parent_pid
= parent_ptid
.lwp ();
461 child_pid
= child_ptid
.lwp ();
463 /* We're already attached to the parent, by default. */
464 child_lp
= add_lwp (child_ptid
);
465 child_lp
->stopped
= 1;
466 child_lp
->last_resume_kind
= resume_stop
;
468 /* Detach new forked process? */
471 int child_stop_signal
= 0;
472 bool detach_child
= true;
474 /* Move CHILD_LP into a unique_ptr and clear the source pointer
475 to prevent us doing anything stupid with it. */
476 lwp_info_up
child_lp_ptr (child_lp
);
479 linux_target
->low_prepare_to_resume (child_lp_ptr
.get ());
481 /* When debugging an inferior in an architecture that supports
482 hardware single stepping on a kernel without commit
483 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
484 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
485 set if the parent process had them set.
486 To work around this, single step the child process
487 once before detaching to clear the flags. */
489 /* Note that we consult the parent's architecture instead of
490 the child's because there's no inferior for the child at
492 if (!gdbarch_software_single_step_p (target_thread_architecture
497 linux_disable_event_reporting (child_pid
);
498 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
499 perror_with_name (_("Couldn't do single step"));
500 if (my_waitpid (child_pid
, &status
, 0) < 0)
501 perror_with_name (_("Couldn't wait vfork process"));
504 detach_child
= WIFSTOPPED (status
);
505 child_stop_signal
= WSTOPSIG (status
);
511 int signo
= child_stop_signal
;
514 && !signal_pass_state (gdb_signal_from_host (signo
)))
516 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
521 scoped_restore save_inferior_ptid
522 = make_scoped_restore (&inferior_ptid
);
523 inferior_ptid
= child_ptid
;
525 /* Let the thread_db layer learn about this new process. */
526 check_for_thread_db ();
531 struct lwp_info
*parent_lp
;
533 parent_lp
= find_lwp_pid (parent_ptid
);
534 gdb_assert (linux_supports_tracefork () >= 0);
536 if (linux_supports_tracevforkdone ())
539 fprintf_unfiltered (gdb_stdlog
,
540 "LCFF: waiting for VFORK_DONE on %d\n",
542 parent_lp
->stopped
= 1;
544 /* We'll handle the VFORK_DONE event like any other
545 event, in target_wait. */
549 /* We can't insert breakpoints until the child has
550 finished with the shared memory region. We need to
551 wait until that happens. Ideal would be to just
553 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
554 - waitpid (parent_pid, &status, __WALL);
555 However, most architectures can't handle a syscall
556 being traced on the way out if it wasn't traced on
559 We might also think to loop, continuing the child
560 until it exits or gets a SIGTRAP. One problem is
561 that the child might call ptrace with PTRACE_TRACEME.
563 There's no simple and reliable way to figure out when
564 the vforked child will be done with its copy of the
565 shared memory. We could step it out of the syscall,
566 two instructions, let it go, and then single-step the
567 parent once. When we have hardware single-step, this
568 would work; with software single-step it could still
569 be made to work but we'd have to be able to insert
570 single-step breakpoints in the child, and we'd have
571 to insert -just- the single-step breakpoint in the
572 parent. Very awkward.
574 In the end, the best we can do is to make sure it
575 runs for a little while. Hopefully it will be out of
576 range of any breakpoints we reinsert. Usually this
577 is only the single-step breakpoint at vfork's return
581 fprintf_unfiltered (gdb_stdlog
,
582 "LCFF: no VFORK_DONE "
583 "support, sleeping a bit\n");
587 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
588 and leave it pending. The next linux_nat_resume call
589 will notice a pending event, and bypasses actually
590 resuming the inferior. */
591 parent_lp
->status
= 0;
592 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
593 parent_lp
->stopped
= 1;
595 /* If we're in async mode, need to tell the event loop
596 there's something here to process. */
597 if (target_is_async_p ())
604 struct lwp_info
*child_lp
;
606 child_lp
= add_lwp (inferior_ptid
);
607 child_lp
->stopped
= 1;
608 child_lp
->last_resume_kind
= resume_stop
;
610 /* Let the thread_db layer learn about this new process. */
611 check_for_thread_db ();
619 linux_nat_target::insert_fork_catchpoint (int pid
)
621 return !linux_supports_tracefork ();
625 linux_nat_target::remove_fork_catchpoint (int pid
)
631 linux_nat_target::insert_vfork_catchpoint (int pid
)
633 return !linux_supports_tracefork ();
637 linux_nat_target::remove_vfork_catchpoint (int pid
)
643 linux_nat_target::insert_exec_catchpoint (int pid
)
645 return !linux_supports_tracefork ();
649 linux_nat_target::remove_exec_catchpoint (int pid
)
655 linux_nat_target::set_syscall_catchpoint (int pid
, bool needed
, int any_count
,
656 gdb::array_view
<const int> syscall_counts
)
658 if (!linux_supports_tracesysgood ())
661 /* On GNU/Linux, we ignore the arguments. It means that we only
662 enable the syscall catchpoints, but do not disable them.
664 Also, we do not use the `syscall_counts' information because we do not
665 filter system calls here. We let GDB do the logic for us. */
669 /* List of known LWPs, keyed by LWP PID. This speeds up the common
670 case of mapping a PID returned from the kernel to our corresponding
671 lwp_info data structure. */
672 static htab_t lwp_lwpid_htab
;
674 /* Calculate a hash from a lwp_info's LWP PID. */
677 lwp_info_hash (const void *ap
)
679 const struct lwp_info
*lp
= (struct lwp_info
*) ap
;
680 pid_t pid
= lp
->ptid
.lwp ();
682 return iterative_hash_object (pid
, 0);
685 /* Equality function for the lwp_info hash table. Compares the LWP's
689 lwp_lwpid_htab_eq (const void *a
, const void *b
)
691 const struct lwp_info
*entry
= (const struct lwp_info
*) a
;
692 const struct lwp_info
*element
= (const struct lwp_info
*) b
;
694 return entry
->ptid
.lwp () == element
->ptid
.lwp ();
697 /* Create the lwp_lwpid_htab hash table. */
700 lwp_lwpid_htab_create (void)
702 lwp_lwpid_htab
= htab_create (100, lwp_info_hash
, lwp_lwpid_htab_eq
, NULL
);
705 /* Add LP to the hash table. */
708 lwp_lwpid_htab_add_lwp (struct lwp_info
*lp
)
712 slot
= htab_find_slot (lwp_lwpid_htab
, lp
, INSERT
);
713 gdb_assert (slot
!= NULL
&& *slot
== NULL
);
717 /* Head of doubly-linked list of known LWPs. Sorted by reverse
718 creation order. This order is assumed in some cases. E.g.,
719 reaping status after killing alls lwps of a process: the leader LWP
720 must be reaped last. */
721 struct lwp_info
*lwp_list
;
723 /* Add LP to sorted-by-reverse-creation-order doubly-linked list. */
726 lwp_list_add (struct lwp_info
*lp
)
729 if (lwp_list
!= NULL
)
734 /* Remove LP from sorted-by-reverse-creation-order doubly-linked
738 lwp_list_remove (struct lwp_info
*lp
)
740 /* Remove from sorted-by-creation-order list. */
741 if (lp
->next
!= NULL
)
742 lp
->next
->prev
= lp
->prev
;
743 if (lp
->prev
!= NULL
)
744 lp
->prev
->next
= lp
->next
;
751 /* Original signal mask. */
752 static sigset_t normal_mask
;
754 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
755 _initialize_linux_nat. */
756 static sigset_t suspend_mask
;
758 /* Signals to block to make that sigsuspend work. */
759 static sigset_t blocked_mask
;
761 /* SIGCHLD action. */
762 struct sigaction sigchld_action
;
764 /* Block child signals (SIGCHLD and linux threads signals), and store
765 the previous mask in PREV_MASK. */
768 block_child_signals (sigset_t
*prev_mask
)
770 /* Make sure SIGCHLD is blocked. */
771 if (!sigismember (&blocked_mask
, SIGCHLD
))
772 sigaddset (&blocked_mask
, SIGCHLD
);
774 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
777 /* Restore child signals mask, previously returned by
778 block_child_signals. */
781 restore_child_signals_mask (sigset_t
*prev_mask
)
783 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
786 /* Mask of signals to pass directly to the inferior. */
787 static sigset_t pass_mask
;
789 /* Update signals to pass to the inferior. */
791 linux_nat_target::pass_signals
792 (gdb::array_view
<const unsigned char> pass_signals
)
796 sigemptyset (&pass_mask
);
798 for (signo
= 1; signo
< NSIG
; signo
++)
800 int target_signo
= gdb_signal_from_host (signo
);
801 if (target_signo
< pass_signals
.size () && pass_signals
[target_signo
])
802 sigaddset (&pass_mask
, signo
);
808 /* Prototypes for local functions. */
809 static int stop_wait_callback (struct lwp_info
*lp
);
810 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, const ptid_t wait_ptid
);
811 static int check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
);
815 /* Destroy and free LP. */
818 lwp_free (struct lwp_info
*lp
)
820 /* Let the arch specific bits release arch_lwp_info. */
821 linux_target
->low_delete_thread (lp
->arch_private
);
826 /* Traversal function for purge_lwp_list. */
829 lwp_lwpid_htab_remove_pid (void **slot
, void *info
)
831 struct lwp_info
*lp
= (struct lwp_info
*) *slot
;
832 int pid
= *(int *) info
;
834 if (lp
->ptid
.pid () == pid
)
836 htab_clear_slot (lwp_lwpid_htab
, slot
);
837 lwp_list_remove (lp
);
844 /* Remove all LWPs belong to PID from the lwp list. */
847 purge_lwp_list (int pid
)
849 htab_traverse_noresize (lwp_lwpid_htab
, lwp_lwpid_htab_remove_pid
, &pid
);
852 /* Add the LWP specified by PTID to the list. PTID is the first LWP
853 in the process. Return a pointer to the structure describing the
856 This differs from add_lwp in that we don't let the arch specific
857 bits know about this new thread. Current clients of this callback
858 take the opportunity to install watchpoints in the new thread, and
859 we shouldn't do that for the first thread. If we're spawning a
860 child ("run"), the thread executes the shell wrapper first, and we
861 shouldn't touch it until it execs the program we want to debug.
862 For "attach", it'd be okay to call the callback, but it's not
863 necessary, because watchpoints can't yet have been inserted into
866 static struct lwp_info
*
867 add_initial_lwp (ptid_t ptid
)
871 gdb_assert (ptid
.lwp_p ());
873 lp
= XNEW (struct lwp_info
);
875 memset (lp
, 0, sizeof (struct lwp_info
));
877 lp
->last_resume_kind
= resume_continue
;
878 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
883 /* Add to sorted-by-reverse-creation-order list. */
886 /* Add to keyed-by-pid htab. */
887 lwp_lwpid_htab_add_lwp (lp
);
892 /* Add the LWP specified by PID to the list. Return a pointer to the
893 structure describing the new LWP. The LWP should already be
896 static struct lwp_info
*
897 add_lwp (ptid_t ptid
)
901 lp
= add_initial_lwp (ptid
);
903 /* Let the arch specific bits know about this new thread. Current
904 clients of this callback take the opportunity to install
905 watchpoints in the new thread. We don't do this for the first
906 thread though. See add_initial_lwp. */
907 linux_target
->low_new_thread (lp
);
912 /* Remove the LWP specified by PID from the list. */
915 delete_lwp (ptid_t ptid
)
919 struct lwp_info dummy
;
922 slot
= htab_find_slot (lwp_lwpid_htab
, &dummy
, NO_INSERT
);
926 lp
= *(struct lwp_info
**) slot
;
927 gdb_assert (lp
!= NULL
);
929 htab_clear_slot (lwp_lwpid_htab
, slot
);
931 /* Remove from sorted-by-creation-order list. */
932 lwp_list_remove (lp
);
938 /* Return a pointer to the structure describing the LWP corresponding
939 to PID. If no corresponding LWP could be found, return NULL. */
941 static struct lwp_info
*
942 find_lwp_pid (ptid_t ptid
)
946 struct lwp_info dummy
;
953 dummy
.ptid
= ptid_t (0, lwp
, 0);
954 lp
= (struct lwp_info
*) htab_find (lwp_lwpid_htab
, &dummy
);
958 /* See nat/linux-nat.h. */
961 iterate_over_lwps (ptid_t filter
,
962 gdb::function_view
<iterate_over_lwps_ftype
> callback
)
964 struct lwp_info
*lp
, *lpnext
;
966 for (lp
= lwp_list
; lp
; lp
= lpnext
)
970 if (lp
->ptid
.matches (filter
))
972 if (callback (lp
) != 0)
980 /* Update our internal state when changing from one checkpoint to
981 another indicated by NEW_PTID. We can only switch single-threaded
982 applications, so we only create one new LWP, and the previous list
986 linux_nat_switch_fork (ptid_t new_ptid
)
990 purge_lwp_list (inferior_ptid
.pid ());
992 lp
= add_lwp (new_ptid
);
995 /* This changes the thread's ptid while preserving the gdb thread
996 num. Also changes the inferior pid, while preserving the
998 thread_change_ptid (inferior_ptid
, new_ptid
);
1000 /* We've just told GDB core that the thread changed target id, but,
1001 in fact, it really is a different thread, with different register
1003 registers_changed ();
1006 /* Handle the exit of a single thread LP. */
1009 exit_lwp (struct lwp_info
*lp
)
1011 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1015 if (print_thread_events
)
1016 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
1021 delete_lwp (lp
->ptid
);
1024 /* Wait for the LWP specified by LP, which we have just attached to.
1025 Returns a wait status for that LWP, to cache. */
1028 linux_nat_post_attach_wait (ptid_t ptid
, int *signalled
)
1030 pid_t new_pid
, pid
= ptid
.lwp ();
1033 if (linux_proc_pid_is_stopped (pid
))
1035 if (debug_linux_nat
)
1036 fprintf_unfiltered (gdb_stdlog
,
1037 "LNPAW: Attaching to a stopped process\n");
1039 /* The process is definitely stopped. It is in a job control
1040 stop, unless the kernel predates the TASK_STOPPED /
1041 TASK_TRACED distinction, in which case it might be in a
1042 ptrace stop. Make sure it is in a ptrace stop; from there we
1043 can kill it, signal it, et cetera.
1045 First make sure there is a pending SIGSTOP. Since we are
1046 already attached, the process can not transition from stopped
1047 to running without a PTRACE_CONT; so we know this signal will
1048 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1049 probably already in the queue (unless this kernel is old
1050 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1051 is not an RT signal, it can only be queued once. */
1052 kill_lwp (pid
, SIGSTOP
);
1054 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1055 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1056 ptrace (PTRACE_CONT
, pid
, 0, 0);
1059 /* Make sure the initial process is stopped. The user-level threads
1060 layer might want to poke around in the inferior, and that won't
1061 work if things haven't stabilized yet. */
1062 new_pid
= my_waitpid (pid
, &status
, __WALL
);
1063 gdb_assert (pid
== new_pid
);
1065 if (!WIFSTOPPED (status
))
1067 /* The pid we tried to attach has apparently just exited. */
1068 if (debug_linux_nat
)
1069 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1070 pid
, status_to_str (status
));
1074 if (WSTOPSIG (status
) != SIGSTOP
)
1077 if (debug_linux_nat
)
1078 fprintf_unfiltered (gdb_stdlog
,
1079 "LNPAW: Received %s after attaching\n",
1080 status_to_str (status
));
1087 linux_nat_target::create_inferior (const char *exec_file
,
1088 const std::string
&allargs
,
1089 char **env
, int from_tty
)
1091 maybe_disable_address_space_randomization restore_personality
1092 (disable_randomization
);
1094 /* The fork_child mechanism is synchronous and calls target_wait, so
1095 we have to mask the async mode. */
1097 /* Make sure we report all signals during startup. */
1100 inf_ptrace_target::create_inferior (exec_file
, allargs
, env
, from_tty
);
1103 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1104 already attached. Returns true if a new LWP is found, false
1108 attach_proc_task_lwp_callback (ptid_t ptid
)
1110 struct lwp_info
*lp
;
1112 /* Ignore LWPs we're already attached to. */
1113 lp
= find_lwp_pid (ptid
);
1116 int lwpid
= ptid
.lwp ();
1118 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1122 /* Be quiet if we simply raced with the thread exiting.
1123 EPERM is returned if the thread's task still exists, and
1124 is marked as exited or zombie, as well as other
1125 conditions, so in that case, confirm the status in
1126 /proc/PID/status. */
1128 || (err
== EPERM
&& linux_proc_pid_is_gone (lwpid
)))
1130 if (debug_linux_nat
)
1132 fprintf_unfiltered (gdb_stdlog
,
1133 "Cannot attach to lwp %d: "
1134 "thread is gone (%d: %s)\n",
1135 lwpid
, err
, safe_strerror (err
));
1141 = linux_ptrace_attach_fail_reason_string (ptid
, err
);
1143 warning (_("Cannot attach to lwp %d: %s"),
1144 lwpid
, reason
.c_str ());
1149 if (debug_linux_nat
)
1150 fprintf_unfiltered (gdb_stdlog
,
1151 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1152 target_pid_to_str (ptid
));
1154 lp
= add_lwp (ptid
);
1156 /* The next time we wait for this LWP we'll see a SIGSTOP as
1157 PTRACE_ATTACH brings it to a halt. */
1160 /* We need to wait for a stop before being able to make the
1161 next ptrace call on this LWP. */
1162 lp
->must_set_ptrace_flags
= 1;
1164 /* So that wait collects the SIGSTOP. */
1167 /* Also add the LWP to gdb's thread list, in case a
1168 matching libthread_db is not found (or the process uses
1170 add_thread (lp
->ptid
);
1171 set_running (lp
->ptid
, 1);
1172 set_executing (lp
->ptid
, 1);
1181 linux_nat_target::attach (const char *args
, int from_tty
)
1183 struct lwp_info
*lp
;
1187 /* Make sure we report all signals during attach. */
1192 inf_ptrace_target::attach (args
, from_tty
);
1194 CATCH (ex
, RETURN_MASK_ERROR
)
1196 pid_t pid
= parse_pid_to_attach (args
);
1197 std::string reason
= linux_ptrace_attach_fail_reason (pid
);
1199 if (!reason
.empty ())
1200 throw_error (ex
.error
, "warning: %s\n%s", reason
.c_str (), ex
.message
);
1202 throw_error (ex
.error
, "%s", ex
.message
);
1206 /* The ptrace base target adds the main thread with (pid,0,0)
1207 format. Decorate it with lwp info. */
1208 ptid
= ptid_t (inferior_ptid
.pid (),
1209 inferior_ptid
.pid (),
1211 thread_change_ptid (inferior_ptid
, ptid
);
1213 /* Add the initial process as the first LWP to the list. */
1214 lp
= add_initial_lwp (ptid
);
1216 status
= linux_nat_post_attach_wait (lp
->ptid
, &lp
->signalled
);
1217 if (!WIFSTOPPED (status
))
1219 if (WIFEXITED (status
))
1221 int exit_code
= WEXITSTATUS (status
);
1223 target_terminal::ours ();
1224 target_mourn_inferior (inferior_ptid
);
1226 error (_("Unable to attach: program exited normally."));
1228 error (_("Unable to attach: program exited with code %d."),
1231 else if (WIFSIGNALED (status
))
1233 enum gdb_signal signo
;
1235 target_terminal::ours ();
1236 target_mourn_inferior (inferior_ptid
);
1238 signo
= gdb_signal_from_host (WTERMSIG (status
));
1239 error (_("Unable to attach: program terminated with signal "
1241 gdb_signal_to_name (signo
),
1242 gdb_signal_to_string (signo
));
1245 internal_error (__FILE__
, __LINE__
,
1246 _("unexpected status %d for PID %ld"),
1247 status
, (long) ptid
.lwp ());
1252 /* Save the wait status to report later. */
1254 if (debug_linux_nat
)
1255 fprintf_unfiltered (gdb_stdlog
,
1256 "LNA: waitpid %ld, saving status %s\n",
1257 (long) lp
->ptid
.pid (), status_to_str (status
));
1259 lp
->status
= status
;
1261 /* We must attach to every LWP. If /proc is mounted, use that to
1262 find them now. The inferior may be using raw clone instead of
1263 using pthreads. But even if it is using pthreads, thread_db
1264 walks structures in the inferior's address space to find the list
1265 of threads/LWPs, and those structures may well be corrupted.
1266 Note that once thread_db is loaded, we'll still use it to list
1267 threads and associate pthread info with each LWP. */
1268 linux_proc_attach_tgid_threads (lp
->ptid
.pid (),
1269 attach_proc_task_lwp_callback
);
1271 if (target_can_async_p ())
1275 /* Get pending signal of THREAD as a host signal number, for detaching
1276 purposes. This is the signal the thread last stopped for, which we
1277 need to deliver to the thread when detaching, otherwise, it'd be
1281 get_detach_signal (struct lwp_info
*lp
)
1283 enum gdb_signal signo
= GDB_SIGNAL_0
;
1285 /* If we paused threads momentarily, we may have stored pending
1286 events in lp->status or lp->waitstatus (see stop_wait_callback),
1287 and GDB core hasn't seen any signal for those threads.
1288 Otherwise, the last signal reported to the core is found in the
1289 thread object's stop_signal.
1291 There's a corner case that isn't handled here at present. Only
1292 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1293 stop_signal make sense as a real signal to pass to the inferior.
1294 Some catchpoint related events, like
1295 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1296 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1297 those traps are debug API (ptrace in our case) related and
1298 induced; the inferior wouldn't see them if it wasn't being
1299 traced. Hence, we should never pass them to the inferior, even
1300 when set to pass state. Since this corner case isn't handled by
1301 infrun.c when proceeding with a signal, for consistency, neither
1302 do we handle it here (or elsewhere in the file we check for
1303 signal pass state). Normally SIGTRAP isn't set to pass state, so
1304 this is really a corner case. */
1306 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1307 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1308 else if (lp
->status
)
1309 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1312 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1314 if (target_is_non_stop_p () && !tp
->executing
)
1316 if (tp
->suspend
.waitstatus_pending_p
)
1317 signo
= tp
->suspend
.waitstatus
.value
.sig
;
1319 signo
= tp
->suspend
.stop_signal
;
1321 else if (!target_is_non_stop_p ())
1323 struct target_waitstatus last
;
1326 get_last_target_status (&last_ptid
, &last
);
1328 if (lp
->ptid
.lwp () == last_ptid
.lwp ())
1329 signo
= tp
->suspend
.stop_signal
;
1333 if (signo
== GDB_SIGNAL_0
)
1335 if (debug_linux_nat
)
1336 fprintf_unfiltered (gdb_stdlog
,
1337 "GPT: lwp %s has no pending signal\n",
1338 target_pid_to_str (lp
->ptid
));
1340 else if (!signal_pass_state (signo
))
1342 if (debug_linux_nat
)
1343 fprintf_unfiltered (gdb_stdlog
,
1344 "GPT: lwp %s had signal %s, "
1345 "but it is in no pass state\n",
1346 target_pid_to_str (lp
->ptid
),
1347 gdb_signal_to_string (signo
));
1351 if (debug_linux_nat
)
1352 fprintf_unfiltered (gdb_stdlog
,
1353 "GPT: lwp %s has pending signal %s\n",
1354 target_pid_to_str (lp
->ptid
),
1355 gdb_signal_to_string (signo
));
1357 return gdb_signal_to_host (signo
);
1363 /* Detach from LP. If SIGNO_P is non-NULL, then it points to the
1364 signal number that should be passed to the LWP when detaching.
1365 Otherwise pass any pending signal the LWP may have, if any. */
1368 detach_one_lwp (struct lwp_info
*lp
, int *signo_p
)
1370 int lwpid
= lp
->ptid
.lwp ();
1373 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1375 if (debug_linux_nat
&& lp
->status
)
1376 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1377 strsignal (WSTOPSIG (lp
->status
)),
1378 target_pid_to_str (lp
->ptid
));
1380 /* If there is a pending SIGSTOP, get rid of it. */
1383 if (debug_linux_nat
)
1384 fprintf_unfiltered (gdb_stdlog
,
1385 "DC: Sending SIGCONT to %s\n",
1386 target_pid_to_str (lp
->ptid
));
1388 kill_lwp (lwpid
, SIGCONT
);
1392 if (signo_p
== NULL
)
1394 /* Pass on any pending signal for this LWP. */
1395 signo
= get_detach_signal (lp
);
1400 /* Preparing to resume may try to write registers, and fail if the
1401 lwp is zombie. If that happens, ignore the error. We'll handle
1402 it below, when detach fails with ESRCH. */
1405 linux_target
->low_prepare_to_resume (lp
);
1407 CATCH (ex
, RETURN_MASK_ERROR
)
1409 if (!check_ptrace_stopped_lwp_gone (lp
))
1410 throw_exception (ex
);
1414 if (ptrace (PTRACE_DETACH
, lwpid
, 0, signo
) < 0)
1416 int save_errno
= errno
;
1418 /* We know the thread exists, so ESRCH must mean the lwp is
1419 zombie. This can happen if one of the already-detached
1420 threads exits the whole thread group. In that case we're
1421 still attached, and must reap the lwp. */
1422 if (save_errno
== ESRCH
)
1426 ret
= my_waitpid (lwpid
, &status
, __WALL
);
1429 warning (_("Couldn't reap LWP %d while detaching: %s"),
1430 lwpid
, strerror (errno
));
1432 else if (!WIFEXITED (status
) && !WIFSIGNALED (status
))
1434 warning (_("Reaping LWP %d while detaching "
1435 "returned unexpected status 0x%x"),
1441 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1442 safe_strerror (save_errno
));
1445 else if (debug_linux_nat
)
1447 fprintf_unfiltered (gdb_stdlog
,
1448 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1449 target_pid_to_str (lp
->ptid
),
1453 delete_lwp (lp
->ptid
);
1457 detach_callback (struct lwp_info
*lp
)
1459 /* We don't actually detach from the thread group leader just yet.
1460 If the thread group exits, we must reap the zombie clone lwps
1461 before we're able to reap the leader. */
1462 if (lp
->ptid
.lwp () != lp
->ptid
.pid ())
1463 detach_one_lwp (lp
, NULL
);
1468 linux_nat_target::detach (inferior
*inf
, int from_tty
)
1470 struct lwp_info
*main_lwp
;
1473 /* Don't unregister from the event loop, as there may be other
1474 inferiors running. */
1476 /* Stop all threads before detaching. ptrace requires that the
1477 thread is stopped to sucessfully detach. */
1478 iterate_over_lwps (ptid_t (pid
), stop_callback
);
1479 /* ... and wait until all of them have reported back that
1480 they're no longer running. */
1481 iterate_over_lwps (ptid_t (pid
), stop_wait_callback
);
1483 iterate_over_lwps (ptid_t (pid
), detach_callback
);
1485 /* Only the initial process should be left right now. */
1486 gdb_assert (num_lwps (pid
) == 1);
1488 main_lwp
= find_lwp_pid (ptid_t (pid
));
1490 if (forks_exist_p ())
1492 /* Multi-fork case. The current inferior_ptid is being detached
1493 from, but there are other viable forks to debug. Detach from
1494 the current fork, and context-switch to the first
1496 linux_fork_detach (from_tty
);
1500 target_announce_detach (from_tty
);
1502 /* Pass on any pending signal for the last LWP. */
1503 int signo
= get_detach_signal (main_lwp
);
1505 detach_one_lwp (main_lwp
, &signo
);
1507 detach_success (inf
);
1511 /* Resume execution of the inferior process. If STEP is nonzero,
1512 single-step it. If SIGNAL is nonzero, give it that signal. */
1515 linux_resume_one_lwp_throw (struct lwp_info
*lp
, int step
,
1516 enum gdb_signal signo
)
1520 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1521 We only presently need that if the LWP is stepped though (to
1522 handle the case of stepping a breakpoint instruction). */
1525 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
1527 lp
->stop_pc
= regcache_read_pc (regcache
);
1532 linux_target
->low_prepare_to_resume (lp
);
1533 linux_target
->low_resume (lp
->ptid
, step
, signo
);
1535 /* Successfully resumed. Clear state that no longer makes sense,
1536 and mark the LWP as running. Must not do this before resuming
1537 otherwise if that fails other code will be confused. E.g., we'd
1538 later try to stop the LWP and hang forever waiting for a stop
1539 status. Note that we must not throw after this is cleared,
1540 otherwise handle_zombie_lwp_error would get confused. */
1543 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1544 registers_changed_ptid (lp
->ptid
);
1547 /* Called when we try to resume a stopped LWP and that errors out. If
1548 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1549 or about to become), discard the error, clear any pending status
1550 the LWP may have, and return true (we'll collect the exit status
1551 soon enough). Otherwise, return false. */
1554 check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
)
1556 /* If we get an error after resuming the LWP successfully, we'd
1557 confuse !T state for the LWP being gone. */
1558 gdb_assert (lp
->stopped
);
1560 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1561 because even if ptrace failed with ESRCH, the tracee may be "not
1562 yet fully dead", but already refusing ptrace requests. In that
1563 case the tracee has 'R (Running)' state for a little bit
1564 (observed in Linux 3.18). See also the note on ESRCH in the
1565 ptrace(2) man page. Instead, check whether the LWP has any state
1566 other than ptrace-stopped. */
1568 /* Don't assume anything if /proc/PID/status can't be read. */
1569 if (linux_proc_pid_is_trace_stopped_nowarn (lp
->ptid
.lwp ()) == 0)
1571 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1573 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
1579 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1580 disappears while we try to resume it. */
1583 linux_resume_one_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1587 linux_resume_one_lwp_throw (lp
, step
, signo
);
1589 CATCH (ex
, RETURN_MASK_ERROR
)
1591 if (!check_ptrace_stopped_lwp_gone (lp
))
1592 throw_exception (ex
);
1600 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1604 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
1606 if (inf
->vfork_child
!= NULL
)
1608 if (debug_linux_nat
)
1609 fprintf_unfiltered (gdb_stdlog
,
1610 "RC: Not resuming %s (vfork parent)\n",
1611 target_pid_to_str (lp
->ptid
));
1613 else if (!lwp_status_pending_p (lp
))
1615 if (debug_linux_nat
)
1616 fprintf_unfiltered (gdb_stdlog
,
1617 "RC: Resuming sibling %s, %s, %s\n",
1618 target_pid_to_str (lp
->ptid
),
1619 (signo
!= GDB_SIGNAL_0
1620 ? strsignal (gdb_signal_to_host (signo
))
1622 step
? "step" : "resume");
1624 linux_resume_one_lwp (lp
, step
, signo
);
1628 if (debug_linux_nat
)
1629 fprintf_unfiltered (gdb_stdlog
,
1630 "RC: Not resuming sibling %s (has pending)\n",
1631 target_pid_to_str (lp
->ptid
));
1636 if (debug_linux_nat
)
1637 fprintf_unfiltered (gdb_stdlog
,
1638 "RC: Not resuming sibling %s (not stopped)\n",
1639 target_pid_to_str (lp
->ptid
));
1643 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1644 Resume LWP with the last stop signal, if it is in pass state. */
1647 linux_nat_resume_callback (struct lwp_info
*lp
, struct lwp_info
*except
)
1649 enum gdb_signal signo
= GDB_SIGNAL_0
;
1656 struct thread_info
*thread
;
1658 thread
= find_thread_ptid (lp
->ptid
);
1661 signo
= thread
->suspend
.stop_signal
;
1662 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1666 resume_lwp (lp
, 0, signo
);
1671 resume_clear_callback (struct lwp_info
*lp
)
1674 lp
->last_resume_kind
= resume_stop
;
1679 resume_set_callback (struct lwp_info
*lp
)
1682 lp
->last_resume_kind
= resume_continue
;
1687 linux_nat_target::resume (ptid_t ptid
, int step
, enum gdb_signal signo
)
1689 struct lwp_info
*lp
;
1692 if (debug_linux_nat
)
1693 fprintf_unfiltered (gdb_stdlog
,
1694 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1695 step
? "step" : "resume",
1696 target_pid_to_str (ptid
),
1697 (signo
!= GDB_SIGNAL_0
1698 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1699 target_pid_to_str (inferior_ptid
));
1701 /* A specific PTID means `step only this process id'. */
1702 resume_many
= (minus_one_ptid
== ptid
1705 /* Mark the lwps we're resuming as resumed. */
1706 iterate_over_lwps (ptid
, resume_set_callback
);
1708 /* See if it's the current inferior that should be handled
1711 lp
= find_lwp_pid (inferior_ptid
);
1713 lp
= find_lwp_pid (ptid
);
1714 gdb_assert (lp
!= NULL
);
1716 /* Remember if we're stepping. */
1717 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1719 /* If we have a pending wait status for this thread, there is no
1720 point in resuming the process. But first make sure that
1721 linux_nat_wait won't preemptively handle the event - we
1722 should never take this short-circuit if we are going to
1723 leave LP running, since we have skipped resuming all the
1724 other threads. This bit of code needs to be synchronized
1725 with linux_nat_wait. */
1727 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1730 && WSTOPSIG (lp
->status
)
1731 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1733 if (debug_linux_nat
)
1734 fprintf_unfiltered (gdb_stdlog
,
1735 "LLR: Not short circuiting for ignored "
1736 "status 0x%x\n", lp
->status
);
1738 /* FIXME: What should we do if we are supposed to continue
1739 this thread with a signal? */
1740 gdb_assert (signo
== GDB_SIGNAL_0
);
1741 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1746 if (lwp_status_pending_p (lp
))
1748 /* FIXME: What should we do if we are supposed to continue
1749 this thread with a signal? */
1750 gdb_assert (signo
== GDB_SIGNAL_0
);
1752 if (debug_linux_nat
)
1753 fprintf_unfiltered (gdb_stdlog
,
1754 "LLR: Short circuiting for status 0x%x\n",
1757 if (target_can_async_p ())
1760 /* Tell the event loop we have something to process. */
1767 iterate_over_lwps (ptid
, [=] (struct lwp_info
*info
)
1769 return linux_nat_resume_callback (info
, lp
);
1772 if (debug_linux_nat
)
1773 fprintf_unfiltered (gdb_stdlog
,
1774 "LLR: %s %s, %s (resume event thread)\n",
1775 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1776 target_pid_to_str (lp
->ptid
),
1777 (signo
!= GDB_SIGNAL_0
1778 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1780 linux_resume_one_lwp (lp
, step
, signo
);
1782 if (target_can_async_p ())
1786 /* Send a signal to an LWP. */
1789 kill_lwp (int lwpid
, int signo
)
1794 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1795 if (errno
== ENOSYS
)
1797 /* If tkill fails, then we are not using nptl threads, a
1798 configuration we no longer support. */
1799 perror_with_name (("tkill"));
1804 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1805 event, check if the core is interested in it: if not, ignore the
1806 event, and keep waiting; otherwise, we need to toggle the LWP's
1807 syscall entry/exit status, since the ptrace event itself doesn't
1808 indicate it, and report the trap to higher layers. */
1811 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1813 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1814 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1815 thread_info
*thread
= find_thread_ptid (lp
->ptid
);
1816 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, thread
);
1820 /* If we're stopping threads, there's a SIGSTOP pending, which
1821 makes it so that the LWP reports an immediate syscall return,
1822 followed by the SIGSTOP. Skip seeing that "return" using
1823 PTRACE_CONT directly, and let stop_wait_callback collect the
1824 SIGSTOP. Later when the thread is resumed, a new syscall
1825 entry event. If we didn't do this (and returned 0), we'd
1826 leave a syscall entry pending, and our caller, by using
1827 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1828 itself. Later, when the user re-resumes this LWP, we'd see
1829 another syscall entry event and we'd mistake it for a return.
1831 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1832 (leaving immediately with LWP->signalled set, without issuing
1833 a PTRACE_CONT), it would still be problematic to leave this
1834 syscall enter pending, as later when the thread is resumed,
1835 it would then see the same syscall exit mentioned above,
1836 followed by the delayed SIGSTOP, while the syscall didn't
1837 actually get to execute. It seems it would be even more
1838 confusing to the user. */
1840 if (debug_linux_nat
)
1841 fprintf_unfiltered (gdb_stdlog
,
1842 "LHST: ignoring syscall %d "
1843 "for LWP %ld (stopping threads), "
1844 "resuming with PTRACE_CONT for SIGSTOP\n",
1848 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1849 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
1854 /* Always update the entry/return state, even if this particular
1855 syscall isn't interesting to the core now. In async mode,
1856 the user could install a new catchpoint for this syscall
1857 between syscall enter/return, and we'll need to know to
1858 report a syscall return if that happens. */
1859 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1860 ? TARGET_WAITKIND_SYSCALL_RETURN
1861 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1863 if (catch_syscall_enabled ())
1865 if (catching_syscall_number (syscall_number
))
1867 /* Alright, an event to report. */
1868 ourstatus
->kind
= lp
->syscall_state
;
1869 ourstatus
->value
.syscall_number
= syscall_number
;
1871 if (debug_linux_nat
)
1872 fprintf_unfiltered (gdb_stdlog
,
1873 "LHST: stopping for %s of syscall %d"
1876 == TARGET_WAITKIND_SYSCALL_ENTRY
1877 ? "entry" : "return",
1883 if (debug_linux_nat
)
1884 fprintf_unfiltered (gdb_stdlog
,
1885 "LHST: ignoring %s of syscall %d "
1887 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1888 ? "entry" : "return",
1894 /* If we had been syscall tracing, and hence used PT_SYSCALL
1895 before on this LWP, it could happen that the user removes all
1896 syscall catchpoints before we get to process this event.
1897 There are two noteworthy issues here:
1899 - When stopped at a syscall entry event, resuming with
1900 PT_STEP still resumes executing the syscall and reports a
1903 - Only PT_SYSCALL catches syscall enters. If we last
1904 single-stepped this thread, then this event can't be a
1905 syscall enter. If we last single-stepped this thread, this
1906 has to be a syscall exit.
1908 The points above mean that the next resume, be it PT_STEP or
1909 PT_CONTINUE, can not trigger a syscall trace event. */
1910 if (debug_linux_nat
)
1911 fprintf_unfiltered (gdb_stdlog
,
1912 "LHST: caught syscall event "
1913 "with no syscall catchpoints."
1914 " %d for LWP %ld, ignoring\n",
1917 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1920 /* The core isn't interested in this event. For efficiency, avoid
1921 stopping all threads only to have the core resume them all again.
1922 Since we're not stopping threads, if we're still syscall tracing
1923 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1924 subsequent syscall. Simply resume using the inf-ptrace layer,
1925 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1927 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
1931 /* Handle a GNU/Linux extended wait response. If we see a clone
1932 event, we need to add the new LWP to our list (and not report the
1933 trap to higher layers). This function returns non-zero if the
1934 event should be ignored and we should wait again. If STOPPING is
1935 true, the new LWP remains stopped, otherwise it is continued. */
1938 linux_handle_extended_wait (struct lwp_info
*lp
, int status
)
1940 int pid
= lp
->ptid
.lwp ();
1941 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1942 int event
= linux_ptrace_get_extended_event (status
);
1944 /* All extended events we currently use are mid-syscall. Only
1945 PTRACE_EVENT_STOP is delivered more like a signal-stop, but
1946 you have to be using PTRACE_SEIZE to get that. */
1947 lp
->syscall_state
= TARGET_WAITKIND_SYSCALL_ENTRY
;
1949 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1950 || event
== PTRACE_EVENT_CLONE
)
1952 unsigned long new_pid
;
1955 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1957 /* If we haven't already seen the new PID stop, wait for it now. */
1958 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1960 /* The new child has a pending SIGSTOP. We can't affect it until it
1961 hits the SIGSTOP, but we're already attached. */
1962 ret
= my_waitpid (new_pid
, &status
, __WALL
);
1964 perror_with_name (_("waiting for new child"));
1965 else if (ret
!= new_pid
)
1966 internal_error (__FILE__
, __LINE__
,
1967 _("wait returned unexpected PID %d"), ret
);
1968 else if (!WIFSTOPPED (status
))
1969 internal_error (__FILE__
, __LINE__
,
1970 _("wait returned unexpected status 0x%x"), status
);
1973 ourstatus
->value
.related_pid
= ptid_t (new_pid
, new_pid
, 0);
1975 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
1977 /* The arch-specific native code may need to know about new
1978 forks even if those end up never mapped to an
1980 linux_target
->low_new_fork (lp
, new_pid
);
1983 if (event
== PTRACE_EVENT_FORK
1984 && linux_fork_checkpointing_p (lp
->ptid
.pid ()))
1986 /* Handle checkpointing by linux-fork.c here as a special
1987 case. We don't want the follow-fork-mode or 'catch fork'
1988 to interfere with this. */
1990 /* This won't actually modify the breakpoint list, but will
1991 physically remove the breakpoints from the child. */
1992 detach_breakpoints (ptid_t (new_pid
, new_pid
, 0));
1994 /* Retain child fork in ptrace (stopped) state. */
1995 if (!find_fork_pid (new_pid
))
1998 /* Report as spurious, so that infrun doesn't want to follow
1999 this fork. We're actually doing an infcall in
2001 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
2003 /* Report the stop to the core. */
2007 if (event
== PTRACE_EVENT_FORK
)
2008 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
2009 else if (event
== PTRACE_EVENT_VFORK
)
2010 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
2011 else if (event
== PTRACE_EVENT_CLONE
)
2013 struct lwp_info
*new_lp
;
2015 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2017 if (debug_linux_nat
)
2018 fprintf_unfiltered (gdb_stdlog
,
2019 "LHEW: Got clone event "
2020 "from LWP %d, new child is LWP %ld\n",
2023 new_lp
= add_lwp (ptid_t (lp
->ptid
.pid (), new_pid
, 0));
2024 new_lp
->stopped
= 1;
2025 new_lp
->resumed
= 1;
2027 /* If the thread_db layer is active, let it record the user
2028 level thread id and status, and add the thread to GDB's
2030 if (!thread_db_notice_clone (lp
->ptid
, new_lp
->ptid
))
2032 /* The process is not using thread_db. Add the LWP to
2034 target_post_attach (new_lp
->ptid
.lwp ());
2035 add_thread (new_lp
->ptid
);
2038 /* Even if we're stopping the thread for some reason
2039 internal to this module, from the perspective of infrun
2040 and the user/frontend, this new thread is running until
2041 it next reports a stop. */
2042 set_running (new_lp
->ptid
, 1);
2043 set_executing (new_lp
->ptid
, 1);
2045 if (WSTOPSIG (status
) != SIGSTOP
)
2047 /* This can happen if someone starts sending signals to
2048 the new thread before it gets a chance to run, which
2049 have a lower number than SIGSTOP (e.g. SIGUSR1).
2050 This is an unlikely case, and harder to handle for
2051 fork / vfork than for clone, so we do not try - but
2052 we handle it for clone events here. */
2054 new_lp
->signalled
= 1;
2056 /* We created NEW_LP so it cannot yet contain STATUS. */
2057 gdb_assert (new_lp
->status
== 0);
2059 /* Save the wait status to report later. */
2060 if (debug_linux_nat
)
2061 fprintf_unfiltered (gdb_stdlog
,
2062 "LHEW: waitpid of new LWP %ld, "
2063 "saving status %s\n",
2064 (long) new_lp
->ptid
.lwp (),
2065 status_to_str (status
));
2066 new_lp
->status
= status
;
2068 else if (report_thread_events
)
2070 new_lp
->waitstatus
.kind
= TARGET_WAITKIND_THREAD_CREATED
;
2071 new_lp
->status
= status
;
2080 if (event
== PTRACE_EVENT_EXEC
)
2082 if (debug_linux_nat
)
2083 fprintf_unfiltered (gdb_stdlog
,
2084 "LHEW: Got exec event from LWP %ld\n",
2087 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2088 ourstatus
->value
.execd_pathname
2089 = xstrdup (linux_proc_pid_to_exec_file (pid
));
2091 /* The thread that execed must have been resumed, but, when a
2092 thread execs, it changes its tid to the tgid, and the old
2093 tgid thread might have not been resumed. */
2098 if (event
== PTRACE_EVENT_VFORK_DONE
)
2100 if (current_inferior ()->waiting_for_vfork_done
)
2102 if (debug_linux_nat
)
2103 fprintf_unfiltered (gdb_stdlog
,
2104 "LHEW: Got expected PTRACE_EVENT_"
2105 "VFORK_DONE from LWP %ld: stopping\n",
2108 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2112 if (debug_linux_nat
)
2113 fprintf_unfiltered (gdb_stdlog
,
2114 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2115 "from LWP %ld: ignoring\n",
2120 internal_error (__FILE__
, __LINE__
,
2121 _("unknown ptrace event %d"), event
);
2124 /* Suspend waiting for a signal. We're mostly interested in
2130 if (debug_linux_nat
)
2131 fprintf_unfiltered (gdb_stdlog
, "linux-nat: about to sigsuspend\n");
2132 sigsuspend (&suspend_mask
);
2134 /* If the quit flag is set, it means that the user pressed Ctrl-C
2135 and we're debugging a process that is running on a separate
2136 terminal, so we must forward the Ctrl-C to the inferior. (If the
2137 inferior is sharing GDB's terminal, then the Ctrl-C reaches the
2138 inferior directly.) We must do this here because functions that
2139 need to block waiting for a signal loop forever until there's an
2140 event to report before returning back to the event loop. */
2141 if (!target_terminal::is_ours ())
2143 if (check_quit_flag ())
2144 target_pass_ctrlc ();
2148 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2152 wait_lwp (struct lwp_info
*lp
)
2156 int thread_dead
= 0;
2159 gdb_assert (!lp
->stopped
);
2160 gdb_assert (lp
->status
== 0);
2162 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2163 block_child_signals (&prev_mask
);
2167 pid
= my_waitpid (lp
->ptid
.lwp (), &status
, __WALL
| WNOHANG
);
2168 if (pid
== -1 && errno
== ECHILD
)
2170 /* The thread has previously exited. We need to delete it
2171 now because if this was a non-leader thread execing, we
2172 won't get an exit event. See comments on exec events at
2173 the top of the file. */
2175 if (debug_linux_nat
)
2176 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2177 target_pid_to_str (lp
->ptid
));
2182 /* Bugs 10970, 12702.
2183 Thread group leader may have exited in which case we'll lock up in
2184 waitpid if there are other threads, even if they are all zombies too.
2185 Basically, we're not supposed to use waitpid this way.
2186 tkill(pid,0) cannot be used here as it gets ESRCH for both
2187 for zombie and running processes.
2189 As a workaround, check if we're waiting for the thread group leader and
2190 if it's a zombie, and avoid calling waitpid if it is.
2192 This is racy, what if the tgl becomes a zombie right after we check?
2193 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2194 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2196 if (lp
->ptid
.pid () == lp
->ptid
.lwp ()
2197 && linux_proc_pid_is_zombie (lp
->ptid
.lwp ()))
2200 if (debug_linux_nat
)
2201 fprintf_unfiltered (gdb_stdlog
,
2202 "WL: Thread group leader %s vanished.\n",
2203 target_pid_to_str (lp
->ptid
));
2207 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2208 get invoked despite our caller had them intentionally blocked by
2209 block_child_signals. This is sensitive only to the loop of
2210 linux_nat_wait_1 and there if we get called my_waitpid gets called
2211 again before it gets to sigsuspend so we can safely let the handlers
2212 get executed here. */
2216 restore_child_signals_mask (&prev_mask
);
2220 gdb_assert (pid
== lp
->ptid
.lwp ());
2222 if (debug_linux_nat
)
2224 fprintf_unfiltered (gdb_stdlog
,
2225 "WL: waitpid %s received %s\n",
2226 target_pid_to_str (lp
->ptid
),
2227 status_to_str (status
));
2230 /* Check if the thread has exited. */
2231 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2233 if (report_thread_events
2234 || lp
->ptid
.pid () == lp
->ptid
.lwp ())
2236 if (debug_linux_nat
)
2237 fprintf_unfiltered (gdb_stdlog
, "WL: LWP %d exited.\n",
2240 /* If this is the leader exiting, it means the whole
2241 process is gone. Store the status to report to the
2242 core. Store it in lp->waitstatus, because lp->status
2243 would be ambiguous (W_EXITCODE(0,0) == 0). */
2244 store_waitstatus (&lp
->waitstatus
, status
);
2249 if (debug_linux_nat
)
2250 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2251 target_pid_to_str (lp
->ptid
));
2261 gdb_assert (WIFSTOPPED (status
));
2264 if (lp
->must_set_ptrace_flags
)
2266 struct inferior
*inf
= find_inferior_pid (lp
->ptid
.pid ());
2267 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2269 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2270 lp
->must_set_ptrace_flags
= 0;
2273 /* Handle GNU/Linux's syscall SIGTRAPs. */
2274 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2276 /* No longer need the sysgood bit. The ptrace event ends up
2277 recorded in lp->waitstatus if we care for it. We can carry
2278 on handling the event like a regular SIGTRAP from here
2280 status
= W_STOPCODE (SIGTRAP
);
2281 if (linux_handle_syscall_trap (lp
, 1))
2282 return wait_lwp (lp
);
2286 /* Almost all other ptrace-stops are known to be outside of system
2287 calls, with further exceptions in linux_handle_extended_wait. */
2288 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
2291 /* Handle GNU/Linux's extended waitstatus for trace events. */
2292 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2293 && linux_is_extended_waitstatus (status
))
2295 if (debug_linux_nat
)
2296 fprintf_unfiltered (gdb_stdlog
,
2297 "WL: Handling extended status 0x%06x\n",
2299 linux_handle_extended_wait (lp
, status
);
2306 /* Send a SIGSTOP to LP. */
2309 stop_callback (struct lwp_info
*lp
)
2311 if (!lp
->stopped
&& !lp
->signalled
)
2315 if (debug_linux_nat
)
2317 fprintf_unfiltered (gdb_stdlog
,
2318 "SC: kill %s **<SIGSTOP>**\n",
2319 target_pid_to_str (lp
->ptid
));
2322 ret
= kill_lwp (lp
->ptid
.lwp (), SIGSTOP
);
2323 if (debug_linux_nat
)
2325 fprintf_unfiltered (gdb_stdlog
,
2326 "SC: lwp kill %d %s\n",
2328 errno
? safe_strerror (errno
) : "ERRNO-OK");
2332 gdb_assert (lp
->status
== 0);
2338 /* Request a stop on LWP. */
2341 linux_stop_lwp (struct lwp_info
*lwp
)
2343 stop_callback (lwp
);
2346 /* See linux-nat.h */
2349 linux_stop_and_wait_all_lwps (void)
2351 /* Stop all LWP's ... */
2352 iterate_over_lwps (minus_one_ptid
, stop_callback
);
2354 /* ... and wait until all of them have reported back that
2355 they're no longer running. */
2356 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
);
2359 /* See linux-nat.h */
2362 linux_unstop_all_lwps (void)
2364 iterate_over_lwps (minus_one_ptid
,
2365 [] (struct lwp_info
*info
)
2367 return resume_stopped_resumed_lwps (info
, minus_one_ptid
);
2371 /* Return non-zero if LWP PID has a pending SIGINT. */
2374 linux_nat_has_pending_sigint (int pid
)
2376 sigset_t pending
, blocked
, ignored
;
2378 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2380 if (sigismember (&pending
, SIGINT
)
2381 && !sigismember (&ignored
, SIGINT
))
2387 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2390 set_ignore_sigint (struct lwp_info
*lp
)
2392 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2393 flag to consume the next one. */
2394 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2395 && WSTOPSIG (lp
->status
) == SIGINT
)
2398 lp
->ignore_sigint
= 1;
2403 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2404 This function is called after we know the LWP has stopped; if the LWP
2405 stopped before the expected SIGINT was delivered, then it will never have
2406 arrived. Also, if the signal was delivered to a shared queue and consumed
2407 by a different thread, it will never be delivered to this LWP. */
2410 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2412 if (!lp
->ignore_sigint
)
2415 if (!linux_nat_has_pending_sigint (lp
->ptid
.lwp ()))
2417 if (debug_linux_nat
)
2418 fprintf_unfiltered (gdb_stdlog
,
2419 "MCIS: Clearing bogus flag for %s\n",
2420 target_pid_to_str (lp
->ptid
));
2421 lp
->ignore_sigint
= 0;
2425 /* Fetch the possible triggered data watchpoint info and store it in
2428 On some archs, like x86, that use debug registers to set
2429 watchpoints, it's possible that the way to know which watched
2430 address trapped, is to check the register that is used to select
2431 which address to watch. Problem is, between setting the watchpoint
2432 and reading back which data address trapped, the user may change
2433 the set of watchpoints, and, as a consequence, GDB changes the
2434 debug registers in the inferior. To avoid reading back a stale
2435 stopped-data-address when that happens, we cache in LP the fact
2436 that a watchpoint trapped, and the corresponding data address, as
2437 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2438 registers meanwhile, we have the cached data we can rely on. */
2441 check_stopped_by_watchpoint (struct lwp_info
*lp
)
2443 scoped_restore save_inferior_ptid
= make_scoped_restore (&inferior_ptid
);
2444 inferior_ptid
= lp
->ptid
;
2446 if (linux_target
->low_stopped_by_watchpoint ())
2448 lp
->stop_reason
= TARGET_STOPPED_BY_WATCHPOINT
;
2449 lp
->stopped_data_address_p
2450 = linux_target
->low_stopped_data_address (&lp
->stopped_data_address
);
2453 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2456 /* Returns true if the LWP had stopped for a watchpoint. */
2459 linux_nat_target::stopped_by_watchpoint ()
2461 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2463 gdb_assert (lp
!= NULL
);
2465 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2469 linux_nat_target::stopped_data_address (CORE_ADDR
*addr_p
)
2471 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2473 gdb_assert (lp
!= NULL
);
2475 *addr_p
= lp
->stopped_data_address
;
2477 return lp
->stopped_data_address_p
;
2480 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2483 linux_nat_target::low_status_is_event (int status
)
2485 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2488 /* Wait until LP is stopped. */
2491 stop_wait_callback (struct lwp_info
*lp
)
2493 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
2495 /* If this is a vfork parent, bail out, it is not going to report
2496 any SIGSTOP until the vfork is done with. */
2497 if (inf
->vfork_child
!= NULL
)
2504 status
= wait_lwp (lp
);
2508 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2509 && WSTOPSIG (status
) == SIGINT
)
2511 lp
->ignore_sigint
= 0;
2514 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
2516 if (debug_linux_nat
)
2517 fprintf_unfiltered (gdb_stdlog
,
2518 "PTRACE_CONT %s, 0, 0 (%s) "
2519 "(discarding SIGINT)\n",
2520 target_pid_to_str (lp
->ptid
),
2521 errno
? safe_strerror (errno
) : "OK");
2523 return stop_wait_callback (lp
);
2526 maybe_clear_ignore_sigint (lp
);
2528 if (WSTOPSIG (status
) != SIGSTOP
)
2530 /* The thread was stopped with a signal other than SIGSTOP. */
2532 if (debug_linux_nat
)
2533 fprintf_unfiltered (gdb_stdlog
,
2534 "SWC: Pending event %s in %s\n",
2535 status_to_str ((int) status
),
2536 target_pid_to_str (lp
->ptid
));
2538 /* Save the sigtrap event. */
2539 lp
->status
= status
;
2540 gdb_assert (lp
->signalled
);
2541 save_stop_reason (lp
);
2545 /* We caught the SIGSTOP that we intended to catch. */
2547 if (debug_linux_nat
)
2548 fprintf_unfiltered (gdb_stdlog
,
2549 "SWC: Expected SIGSTOP caught for %s.\n",
2550 target_pid_to_str (lp
->ptid
));
2554 /* If we are waiting for this stop so we can report the thread
2555 stopped then we need to record this status. Otherwise, we can
2556 now discard this stop event. */
2557 if (lp
->last_resume_kind
== resume_stop
)
2559 lp
->status
= status
;
2560 save_stop_reason (lp
);
2568 /* Return non-zero if LP has a wait status pending. Discard the
2569 pending event and resume the LWP if the event that originally
2570 caused the stop became uninteresting. */
2573 status_callback (struct lwp_info
*lp
)
2575 /* Only report a pending wait status if we pretend that this has
2576 indeed been resumed. */
2580 if (!lwp_status_pending_p (lp
))
2583 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
2584 || lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2586 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2590 pc
= regcache_read_pc (regcache
);
2592 if (pc
!= lp
->stop_pc
)
2594 if (debug_linux_nat
)
2595 fprintf_unfiltered (gdb_stdlog
,
2596 "SC: PC of %s changed. was=%s, now=%s\n",
2597 target_pid_to_str (lp
->ptid
),
2598 paddress (target_gdbarch (), lp
->stop_pc
),
2599 paddress (target_gdbarch (), pc
));
2603 #if !USE_SIGTRAP_SIGINFO
2604 else if (!breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2606 if (debug_linux_nat
)
2607 fprintf_unfiltered (gdb_stdlog
,
2608 "SC: previous breakpoint of %s, at %s gone\n",
2609 target_pid_to_str (lp
->ptid
),
2610 paddress (target_gdbarch (), lp
->stop_pc
));
2618 if (debug_linux_nat
)
2619 fprintf_unfiltered (gdb_stdlog
,
2620 "SC: pending event of %s cancelled.\n",
2621 target_pid_to_str (lp
->ptid
));
2624 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2632 /* Count the LWP's that have had events. */
2635 count_events_callback (struct lwp_info
*lp
, int *count
)
2637 gdb_assert (count
!= NULL
);
2639 /* Select only resumed LWPs that have an event pending. */
2640 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2646 /* Select the LWP (if any) that is currently being single-stepped. */
2649 select_singlestep_lwp_callback (struct lwp_info
*lp
)
2651 if (lp
->last_resume_kind
== resume_step
2658 /* Returns true if LP has a status pending. */
2661 lwp_status_pending_p (struct lwp_info
*lp
)
2663 /* We check for lp->waitstatus in addition to lp->status, because we
2664 can have pending process exits recorded in lp->status and
2665 W_EXITCODE(0,0) happens to be 0. */
2666 return lp
->status
!= 0 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
;
2669 /* Select the Nth LWP that has had an event. */
2672 select_event_lwp_callback (struct lwp_info
*lp
, int *selector
)
2674 gdb_assert (selector
!= NULL
);
2676 /* Select only resumed LWPs that have an event pending. */
2677 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2678 if ((*selector
)-- == 0)
2684 /* Called when the LWP stopped for a signal/trap. If it stopped for a
2685 trap check what caused it (breakpoint, watchpoint, trace, etc.),
2686 and save the result in the LWP's stop_reason field. If it stopped
2687 for a breakpoint, decrement the PC if necessary on the lwp's
2691 save_stop_reason (struct lwp_info
*lp
)
2693 struct regcache
*regcache
;
2694 struct gdbarch
*gdbarch
;
2697 #if USE_SIGTRAP_SIGINFO
2701 gdb_assert (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
);
2702 gdb_assert (lp
->status
!= 0);
2704 if (!linux_target
->low_status_is_event (lp
->status
))
2707 regcache
= get_thread_regcache (lp
->ptid
);
2708 gdbarch
= regcache
->arch ();
2710 pc
= regcache_read_pc (regcache
);
2711 sw_bp_pc
= pc
- gdbarch_decr_pc_after_break (gdbarch
);
2713 #if USE_SIGTRAP_SIGINFO
2714 if (linux_nat_get_siginfo (lp
->ptid
, &siginfo
))
2716 if (siginfo
.si_signo
== SIGTRAP
)
2718 if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
)
2719 && GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2721 /* The si_code is ambiguous on this arch -- check debug
2723 if (!check_stopped_by_watchpoint (lp
))
2724 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2726 else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
))
2728 /* If we determine the LWP stopped for a SW breakpoint,
2729 trust it. Particularly don't check watchpoint
2730 registers, because at least on s390, we'd find
2731 stopped-by-watchpoint as long as there's a watchpoint
2733 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2735 else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2737 /* This can indicate either a hardware breakpoint or
2738 hardware watchpoint. Check debug registers. */
2739 if (!check_stopped_by_watchpoint (lp
))
2740 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2742 else if (siginfo
.si_code
== TRAP_TRACE
)
2744 if (debug_linux_nat
)
2745 fprintf_unfiltered (gdb_stdlog
,
2746 "CSBB: %s stopped by trace\n",
2747 target_pid_to_str (lp
->ptid
));
2749 /* We may have single stepped an instruction that
2750 triggered a watchpoint. In that case, on some
2751 architectures (such as x86), instead of TRAP_HWBKPT,
2752 si_code indicates TRAP_TRACE, and we need to check
2753 the debug registers separately. */
2754 check_stopped_by_watchpoint (lp
);
2759 if ((!lp
->step
|| lp
->stop_pc
== sw_bp_pc
)
2760 && software_breakpoint_inserted_here_p (regcache
->aspace (),
2763 /* The LWP was either continued, or stepped a software
2764 breakpoint instruction. */
2765 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2768 if (hardware_breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2769 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2771 if (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
)
2772 check_stopped_by_watchpoint (lp
);
2775 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
)
2777 if (debug_linux_nat
)
2778 fprintf_unfiltered (gdb_stdlog
,
2779 "CSBB: %s stopped by software breakpoint\n",
2780 target_pid_to_str (lp
->ptid
));
2782 /* Back up the PC if necessary. */
2784 regcache_write_pc (regcache
, sw_bp_pc
);
2786 /* Update this so we record the correct stop PC below. */
2789 else if (lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2791 if (debug_linux_nat
)
2792 fprintf_unfiltered (gdb_stdlog
,
2793 "CSBB: %s stopped by hardware breakpoint\n",
2794 target_pid_to_str (lp
->ptid
));
2796 else if (lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
)
2798 if (debug_linux_nat
)
2799 fprintf_unfiltered (gdb_stdlog
,
2800 "CSBB: %s stopped by hardware watchpoint\n",
2801 target_pid_to_str (lp
->ptid
));
2808 /* Returns true if the LWP had stopped for a software breakpoint. */
2811 linux_nat_target::stopped_by_sw_breakpoint ()
2813 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2815 gdb_assert (lp
!= NULL
);
2817 return lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
;
2820 /* Implement the supports_stopped_by_sw_breakpoint method. */
2823 linux_nat_target::supports_stopped_by_sw_breakpoint ()
2825 return USE_SIGTRAP_SIGINFO
;
2828 /* Returns true if the LWP had stopped for a hardware
2829 breakpoint/watchpoint. */
2832 linux_nat_target::stopped_by_hw_breakpoint ()
2834 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2836 gdb_assert (lp
!= NULL
);
2838 return lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
;
2841 /* Implement the supports_stopped_by_hw_breakpoint method. */
2844 linux_nat_target::supports_stopped_by_hw_breakpoint ()
2846 return USE_SIGTRAP_SIGINFO
;
2849 /* Select one LWP out of those that have events pending. */
2852 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2855 int random_selector
;
2856 struct lwp_info
*event_lp
= NULL
;
2858 /* Record the wait status for the original LWP. */
2859 (*orig_lp
)->status
= *status
;
2861 /* In all-stop, give preference to the LWP that is being
2862 single-stepped. There will be at most one, and it will be the
2863 LWP that the core is most interested in. If we didn't do this,
2864 then we'd have to handle pending step SIGTRAPs somehow in case
2865 the core later continues the previously-stepped thread, as
2866 otherwise we'd report the pending SIGTRAP then, and the core, not
2867 having stepped the thread, wouldn't understand what the trap was
2868 for, and therefore would report it to the user as a random
2870 if (!target_is_non_stop_p ())
2872 event_lp
= iterate_over_lwps (filter
, select_singlestep_lwp_callback
);
2873 if (event_lp
!= NULL
)
2875 if (debug_linux_nat
)
2876 fprintf_unfiltered (gdb_stdlog
,
2877 "SEL: Select single-step %s\n",
2878 target_pid_to_str (event_lp
->ptid
));
2882 if (event_lp
== NULL
)
2884 /* Pick one at random, out of those which have had events. */
2886 /* First see how many events we have. */
2887 iterate_over_lwps (filter
,
2888 [&] (struct lwp_info
*info
)
2890 return count_events_callback (info
, &num_events
);
2892 gdb_assert (num_events
> 0);
2894 /* Now randomly pick a LWP out of those that have had
2896 random_selector
= (int)
2897 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2899 if (debug_linux_nat
&& num_events
> 1)
2900 fprintf_unfiltered (gdb_stdlog
,
2901 "SEL: Found %d events, selecting #%d\n",
2902 num_events
, random_selector
);
2905 = (iterate_over_lwps
2907 [&] (struct lwp_info
*info
)
2909 return select_event_lwp_callback (info
,
2914 if (event_lp
!= NULL
)
2916 /* Switch the event LWP. */
2917 *orig_lp
= event_lp
;
2918 *status
= event_lp
->status
;
2921 /* Flush the wait status for the event LWP. */
2922 (*orig_lp
)->status
= 0;
2925 /* Return non-zero if LP has been resumed. */
2928 resumed_callback (struct lwp_info
*lp
)
2933 /* Check if we should go on and pass this event to common code.
2934 Return the affected lwp if we are, or NULL otherwise. */
2936 static struct lwp_info
*
2937 linux_nat_filter_event (int lwpid
, int status
)
2939 struct lwp_info
*lp
;
2940 int event
= linux_ptrace_get_extended_event (status
);
2942 lp
= find_lwp_pid (ptid_t (lwpid
));
2944 /* Check for stop events reported by a process we didn't already
2945 know about - anything not already in our LWP list.
2947 If we're expecting to receive stopped processes after
2948 fork, vfork, and clone events, then we'll just add the
2949 new one to our list and go back to waiting for the event
2950 to be reported - the stopped process might be returned
2951 from waitpid before or after the event is.
2953 But note the case of a non-leader thread exec'ing after the
2954 leader having exited, and gone from our lists. The non-leader
2955 thread changes its tid to the tgid. */
2957 if (WIFSTOPPED (status
) && lp
== NULL
2958 && (WSTOPSIG (status
) == SIGTRAP
&& event
== PTRACE_EVENT_EXEC
))
2960 /* A multi-thread exec after we had seen the leader exiting. */
2961 if (debug_linux_nat
)
2962 fprintf_unfiltered (gdb_stdlog
,
2963 "LLW: Re-adding thread group leader LWP %d.\n",
2966 lp
= add_lwp (ptid_t (lwpid
, lwpid
, 0));
2969 add_thread (lp
->ptid
);
2972 if (WIFSTOPPED (status
) && !lp
)
2974 if (debug_linux_nat
)
2975 fprintf_unfiltered (gdb_stdlog
,
2976 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2977 (long) lwpid
, status_to_str (status
));
2978 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2982 /* Make sure we don't report an event for the exit of an LWP not in
2983 our list, i.e. not part of the current process. This can happen
2984 if we detach from a program we originally forked and then it
2986 if (!WIFSTOPPED (status
) && !lp
)
2989 /* This LWP is stopped now. (And if dead, this prevents it from
2990 ever being continued.) */
2993 if (WIFSTOPPED (status
) && lp
->must_set_ptrace_flags
)
2995 struct inferior
*inf
= find_inferior_pid (lp
->ptid
.pid ());
2996 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2998 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2999 lp
->must_set_ptrace_flags
= 0;
3002 /* Handle GNU/Linux's syscall SIGTRAPs. */
3003 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
3005 /* No longer need the sysgood bit. The ptrace event ends up
3006 recorded in lp->waitstatus if we care for it. We can carry
3007 on handling the event like a regular SIGTRAP from here
3009 status
= W_STOPCODE (SIGTRAP
);
3010 if (linux_handle_syscall_trap (lp
, 0))
3015 /* Almost all other ptrace-stops are known to be outside of system
3016 calls, with further exceptions in linux_handle_extended_wait. */
3017 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
3020 /* Handle GNU/Linux's extended waitstatus for trace events. */
3021 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
3022 && linux_is_extended_waitstatus (status
))
3024 if (debug_linux_nat
)
3025 fprintf_unfiltered (gdb_stdlog
,
3026 "LLW: Handling extended status 0x%06x\n",
3028 if (linux_handle_extended_wait (lp
, status
))
3032 /* Check if the thread has exited. */
3033 if (WIFEXITED (status
) || WIFSIGNALED (status
))
3035 if (!report_thread_events
3036 && num_lwps (lp
->ptid
.pid ()) > 1)
3038 if (debug_linux_nat
)
3039 fprintf_unfiltered (gdb_stdlog
,
3040 "LLW: %s exited.\n",
3041 target_pid_to_str (lp
->ptid
));
3043 /* If there is at least one more LWP, then the exit signal
3044 was not the end of the debugged application and should be
3050 /* Note that even if the leader was ptrace-stopped, it can still
3051 exit, if e.g., some other thread brings down the whole
3052 process (calls `exit'). So don't assert that the lwp is
3054 if (debug_linux_nat
)
3055 fprintf_unfiltered (gdb_stdlog
,
3056 "LWP %ld exited (resumed=%d)\n",
3057 lp
->ptid
.lwp (), lp
->resumed
);
3059 /* Dead LWP's aren't expected to reported a pending sigstop. */
3062 /* Store the pending event in the waitstatus, because
3063 W_EXITCODE(0,0) == 0. */
3064 store_waitstatus (&lp
->waitstatus
, status
);
3068 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3069 an attempt to stop an LWP. */
3071 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3075 if (lp
->last_resume_kind
== resume_stop
)
3077 if (debug_linux_nat
)
3078 fprintf_unfiltered (gdb_stdlog
,
3079 "LLW: resume_stop SIGSTOP caught for %s.\n",
3080 target_pid_to_str (lp
->ptid
));
3084 /* This is a delayed SIGSTOP. Filter out the event. */
3086 if (debug_linux_nat
)
3087 fprintf_unfiltered (gdb_stdlog
,
3088 "LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
3090 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3091 target_pid_to_str (lp
->ptid
));
3093 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3094 gdb_assert (lp
->resumed
);
3099 /* Make sure we don't report a SIGINT that we have already displayed
3100 for another thread. */
3101 if (lp
->ignore_sigint
3102 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3104 if (debug_linux_nat
)
3105 fprintf_unfiltered (gdb_stdlog
,
3106 "LLW: Delayed SIGINT caught for %s.\n",
3107 target_pid_to_str (lp
->ptid
));
3109 /* This is a delayed SIGINT. */
3110 lp
->ignore_sigint
= 0;
3112 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3113 if (debug_linux_nat
)
3114 fprintf_unfiltered (gdb_stdlog
,
3115 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3117 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3118 target_pid_to_str (lp
->ptid
));
3119 gdb_assert (lp
->resumed
);
3121 /* Discard the event. */
3125 /* Don't report signals that GDB isn't interested in, such as
3126 signals that are neither printed nor stopped upon. Stopping all
3127 threads can be a bit time-consuming so if we want decent
3128 performance with heavily multi-threaded programs, especially when
3129 they're using a high frequency timer, we'd better avoid it if we
3131 if (WIFSTOPPED (status
))
3133 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3135 if (!target_is_non_stop_p ())
3137 /* Only do the below in all-stop, as we currently use SIGSTOP
3138 to implement target_stop (see linux_nat_stop) in
3140 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3142 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3143 forwarded to the entire process group, that is, all LWPs
3144 will receive it - unless they're using CLONE_THREAD to
3145 share signals. Since we only want to report it once, we
3146 mark it as ignored for all LWPs except this one. */
3147 iterate_over_lwps (ptid_t (lp
->ptid
.pid ()), set_ignore_sigint
);
3148 lp
->ignore_sigint
= 0;
3151 maybe_clear_ignore_sigint (lp
);
3154 /* When using hardware single-step, we need to report every signal.
3155 Otherwise, signals in pass_mask may be short-circuited
3156 except signals that might be caused by a breakpoint. */
3158 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
))
3159 && !linux_wstatus_maybe_breakpoint (status
))
3161 linux_resume_one_lwp (lp
, lp
->step
, signo
);
3162 if (debug_linux_nat
)
3163 fprintf_unfiltered (gdb_stdlog
,
3164 "LLW: %s %s, %s (preempt 'handle')\n",
3166 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3167 target_pid_to_str (lp
->ptid
),
3168 (signo
!= GDB_SIGNAL_0
3169 ? strsignal (gdb_signal_to_host (signo
))
3175 /* An interesting event. */
3177 lp
->status
= status
;
3178 save_stop_reason (lp
);
3182 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3183 their exits until all other threads in the group have exited. */
3186 check_zombie_leaders (void)
3188 for (inferior
*inf
: all_inferiors ())
3190 struct lwp_info
*leader_lp
;
3195 leader_lp
= find_lwp_pid (ptid_t (inf
->pid
));
3196 if (leader_lp
!= NULL
3197 /* Check if there are other threads in the group, as we may
3198 have raced with the inferior simply exiting. */
3199 && num_lwps (inf
->pid
) > 1
3200 && linux_proc_pid_is_zombie (inf
->pid
))
3202 if (debug_linux_nat
)
3203 fprintf_unfiltered (gdb_stdlog
,
3204 "CZL: Thread group leader %d zombie "
3205 "(it exited, or another thread execd).\n",
3208 /* A leader zombie can mean one of two things:
3210 - It exited, and there's an exit status pending
3211 available, or only the leader exited (not the whole
3212 program). In the latter case, we can't waitpid the
3213 leader's exit status until all other threads are gone.
3215 - There are 3 or more threads in the group, and a thread
3216 other than the leader exec'd. See comments on exec
3217 events at the top of the file. We could try
3218 distinguishing the exit and exec cases, by waiting once
3219 more, and seeing if something comes out, but it doesn't
3220 sound useful. The previous leader _does_ go away, and
3221 we'll re-add the new one once we see the exec event
3222 (which is just the same as what would happen if the
3223 previous leader did exit voluntarily before some other
3226 if (debug_linux_nat
)
3227 fprintf_unfiltered (gdb_stdlog
,
3228 "CZL: Thread group leader %d vanished.\n",
3230 exit_lwp (leader_lp
);
3235 /* Convenience function that is called when the kernel reports an exit
3236 event. This decides whether to report the event to GDB as a
3237 process exit event, a thread exit event, or to suppress the
3241 filter_exit_event (struct lwp_info
*event_child
,
3242 struct target_waitstatus
*ourstatus
)
3244 ptid_t ptid
= event_child
->ptid
;
3246 if (num_lwps (ptid
.pid ()) > 1)
3248 if (report_thread_events
)
3249 ourstatus
->kind
= TARGET_WAITKIND_THREAD_EXITED
;
3251 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3253 exit_lwp (event_child
);
3260 linux_nat_wait_1 (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3264 enum resume_kind last_resume_kind
;
3265 struct lwp_info
*lp
;
3268 if (debug_linux_nat
)
3269 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3271 /* The first time we get here after starting a new inferior, we may
3272 not have added it to the LWP list yet - this is the earliest
3273 moment at which we know its PID. */
3274 if (inferior_ptid
.is_pid ())
3276 /* Upgrade the main thread's ptid. */
3277 thread_change_ptid (inferior_ptid
,
3278 ptid_t (inferior_ptid
.pid (),
3279 inferior_ptid
.pid (), 0));
3281 lp
= add_initial_lwp (inferior_ptid
);
3285 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3286 block_child_signals (&prev_mask
);
3288 /* First check if there is a LWP with a wait status pending. */
3289 lp
= iterate_over_lwps (ptid
, status_callback
);
3292 if (debug_linux_nat
)
3293 fprintf_unfiltered (gdb_stdlog
,
3294 "LLW: Using pending wait status %s for %s.\n",
3295 status_to_str (lp
->status
),
3296 target_pid_to_str (lp
->ptid
));
3299 /* But if we don't find a pending event, we'll have to wait. Always
3300 pull all events out of the kernel. We'll randomly select an
3301 event LWP out of all that have events, to prevent starvation. */
3307 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3310 - If the thread group leader exits while other threads in the
3311 thread group still exist, waitpid(TGID, ...) hangs. That
3312 waitpid won't return an exit status until the other threads
3313 in the group are reapped.
3315 - When a non-leader thread execs, that thread just vanishes
3316 without reporting an exit (so we'd hang if we waited for it
3317 explicitly in that case). The exec event is reported to
3321 lwpid
= my_waitpid (-1, &status
, __WALL
| WNOHANG
);
3323 if (debug_linux_nat
)
3324 fprintf_unfiltered (gdb_stdlog
,
3325 "LNW: waitpid(-1, ...) returned %d, %s\n",
3326 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3330 if (debug_linux_nat
)
3332 fprintf_unfiltered (gdb_stdlog
,
3333 "LLW: waitpid %ld received %s\n",
3334 (long) lwpid
, status_to_str (status
));
3337 linux_nat_filter_event (lwpid
, status
);
3338 /* Retry until nothing comes out of waitpid. A single
3339 SIGCHLD can indicate more than one child stopped. */
3343 /* Now that we've pulled all events out of the kernel, resume
3344 LWPs that don't have an interesting event to report. */
3345 iterate_over_lwps (minus_one_ptid
,
3346 [] (struct lwp_info
*info
)
3348 return resume_stopped_resumed_lwps (info
, minus_one_ptid
);
3351 /* ... and find an LWP with a status to report to the core, if
3353 lp
= iterate_over_lwps (ptid
, status_callback
);
3357 /* Check for zombie thread group leaders. Those can't be reaped
3358 until all other threads in the thread group are. */
3359 check_zombie_leaders ();
3361 /* If there are no resumed children left, bail. We'd be stuck
3362 forever in the sigsuspend call below otherwise. */
3363 if (iterate_over_lwps (ptid
, resumed_callback
) == NULL
)
3365 if (debug_linux_nat
)
3366 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3368 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3370 restore_child_signals_mask (&prev_mask
);
3371 return minus_one_ptid
;
3374 /* No interesting event to report to the core. */
3376 if (target_options
& TARGET_WNOHANG
)
3378 if (debug_linux_nat
)
3379 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3381 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3382 restore_child_signals_mask (&prev_mask
);
3383 return minus_one_ptid
;
3386 /* We shouldn't end up here unless we want to try again. */
3387 gdb_assert (lp
== NULL
);
3389 /* Block until we get an event reported with SIGCHLD. */
3395 status
= lp
->status
;
3398 if (!target_is_non_stop_p ())
3400 /* Now stop all other LWP's ... */
3401 iterate_over_lwps (minus_one_ptid
, stop_callback
);
3403 /* ... and wait until all of them have reported back that
3404 they're no longer running. */
3405 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
);
3408 /* If we're not waiting for a specific LWP, choose an event LWP from
3409 among those that have had events. Giving equal priority to all
3410 LWPs that have had events helps prevent starvation. */
3411 if (ptid
== minus_one_ptid
|| ptid
.is_pid ())
3412 select_event_lwp (ptid
, &lp
, &status
);
3414 gdb_assert (lp
!= NULL
);
3416 /* Now that we've selected our final event LWP, un-adjust its PC if
3417 it was a software breakpoint, and we can't reliably support the
3418 "stopped by software breakpoint" stop reason. */
3419 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
3420 && !USE_SIGTRAP_SIGINFO
)
3422 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3423 struct gdbarch
*gdbarch
= regcache
->arch ();
3424 int decr_pc
= gdbarch_decr_pc_after_break (gdbarch
);
3430 pc
= regcache_read_pc (regcache
);
3431 regcache_write_pc (regcache
, pc
+ decr_pc
);
3435 /* We'll need this to determine whether to report a SIGSTOP as
3436 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3438 last_resume_kind
= lp
->last_resume_kind
;
3440 if (!target_is_non_stop_p ())
3442 /* In all-stop, from the core's perspective, all LWPs are now
3443 stopped until a new resume action is sent over. */
3444 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
);
3448 resume_clear_callback (lp
);
3451 if (linux_target
->low_status_is_event (status
))
3453 if (debug_linux_nat
)
3454 fprintf_unfiltered (gdb_stdlog
,
3455 "LLW: trap ptid is %s.\n",
3456 target_pid_to_str (lp
->ptid
));
3459 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3461 *ourstatus
= lp
->waitstatus
;
3462 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3465 store_waitstatus (ourstatus
, status
);
3467 if (debug_linux_nat
)
3468 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3470 restore_child_signals_mask (&prev_mask
);
3472 if (last_resume_kind
== resume_stop
3473 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3474 && WSTOPSIG (status
) == SIGSTOP
)
3476 /* A thread that has been requested to stop by GDB with
3477 target_stop, and it stopped cleanly, so report as SIG0. The
3478 use of SIGSTOP is an implementation detail. */
3479 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3482 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3483 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3486 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3488 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
)
3489 return filter_exit_event (lp
, ourstatus
);
3494 /* Resume LWPs that are currently stopped without any pending status
3495 to report, but are resumed from the core's perspective. */
3498 resume_stopped_resumed_lwps (struct lwp_info
*lp
, const ptid_t wait_ptid
)
3502 if (debug_linux_nat
)
3503 fprintf_unfiltered (gdb_stdlog
,
3504 "RSRL: NOT resuming LWP %s, not stopped\n",
3505 target_pid_to_str (lp
->ptid
));
3507 else if (!lp
->resumed
)
3509 if (debug_linux_nat
)
3510 fprintf_unfiltered (gdb_stdlog
,
3511 "RSRL: NOT resuming LWP %s, not resumed\n",
3512 target_pid_to_str (lp
->ptid
));
3514 else if (lwp_status_pending_p (lp
))
3516 if (debug_linux_nat
)
3517 fprintf_unfiltered (gdb_stdlog
,
3518 "RSRL: NOT resuming LWP %s, has pending status\n",
3519 target_pid_to_str (lp
->ptid
));
3523 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3524 struct gdbarch
*gdbarch
= regcache
->arch ();
3528 CORE_ADDR pc
= regcache_read_pc (regcache
);
3529 int leave_stopped
= 0;
3531 /* Don't bother if there's a breakpoint at PC that we'd hit
3532 immediately, and we're not waiting for this LWP. */
3533 if (!lp
->ptid
.matches (wait_ptid
))
3535 if (breakpoint_inserted_here_p (regcache
->aspace (), pc
))
3541 if (debug_linux_nat
)
3542 fprintf_unfiltered (gdb_stdlog
,
3543 "RSRL: resuming stopped-resumed LWP %s at "
3545 target_pid_to_str (lp
->ptid
),
3546 paddress (gdbarch
, pc
),
3549 linux_resume_one_lwp_throw (lp
, lp
->step
, GDB_SIGNAL_0
);
3552 CATCH (ex
, RETURN_MASK_ERROR
)
3554 if (!check_ptrace_stopped_lwp_gone (lp
))
3555 throw_exception (ex
);
3564 linux_nat_target::wait (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3569 if (debug_linux_nat
)
3571 std::string options_string
= target_options_to_string (target_options
);
3572 fprintf_unfiltered (gdb_stdlog
,
3573 "linux_nat_wait: [%s], [%s]\n",
3574 target_pid_to_str (ptid
),
3575 options_string
.c_str ());
3578 /* Flush the async file first. */
3579 if (target_is_async_p ())
3580 async_file_flush ();
3582 /* Resume LWPs that are currently stopped without any pending status
3583 to report, but are resumed from the core's perspective. LWPs get
3584 in this state if we find them stopping at a time we're not
3585 interested in reporting the event (target_wait on a
3586 specific_process, for example, see linux_nat_wait_1), and
3587 meanwhile the event became uninteresting. Don't bother resuming
3588 LWPs we're not going to wait for if they'd stop immediately. */
3589 if (target_is_non_stop_p ())
3590 iterate_over_lwps (minus_one_ptid
,
3591 [=] (struct lwp_info
*info
)
3593 return resume_stopped_resumed_lwps (info
, ptid
);
3596 event_ptid
= linux_nat_wait_1 (ptid
, ourstatus
, target_options
);
3598 /* If we requested any event, and something came out, assume there
3599 may be more. If we requested a specific lwp or process, also
3600 assume there may be more. */
3601 if (target_is_async_p ()
3602 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3603 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3604 || ptid
!= minus_one_ptid
))
3613 kill_one_lwp (pid_t pid
)
3615 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3618 kill_lwp (pid
, SIGKILL
);
3619 if (debug_linux_nat
)
3621 int save_errno
= errno
;
3623 fprintf_unfiltered (gdb_stdlog
,
3624 "KC: kill (SIGKILL) %ld, 0, 0 (%s)\n", (long) pid
,
3625 save_errno
? safe_strerror (save_errno
) : "OK");
3628 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3631 ptrace (PTRACE_KILL
, pid
, 0, 0);
3632 if (debug_linux_nat
)
3634 int save_errno
= errno
;
3636 fprintf_unfiltered (gdb_stdlog
,
3637 "KC: PTRACE_KILL %ld, 0, 0 (%s)\n", (long) pid
,
3638 save_errno
? safe_strerror (save_errno
) : "OK");
3642 /* Wait for an LWP to die. */
3645 kill_wait_one_lwp (pid_t pid
)
3649 /* We must make sure that there are no pending events (delayed
3650 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3651 program doesn't interfere with any following debugging session. */
3655 res
= my_waitpid (pid
, NULL
, __WALL
);
3656 if (res
!= (pid_t
) -1)
3658 if (debug_linux_nat
)
3659 fprintf_unfiltered (gdb_stdlog
,
3660 "KWC: wait %ld received unknown.\n",
3662 /* The Linux kernel sometimes fails to kill a thread
3663 completely after PTRACE_KILL; that goes from the stop
3664 point in do_fork out to the one in get_signal_to_deliver
3665 and waits again. So kill it again. */
3671 gdb_assert (res
== -1 && errno
== ECHILD
);
3674 /* Callback for iterate_over_lwps. */
3677 kill_callback (struct lwp_info
*lp
)
3679 kill_one_lwp (lp
->ptid
.lwp ());
3683 /* Callback for iterate_over_lwps. */
3686 kill_wait_callback (struct lwp_info
*lp
)
3688 kill_wait_one_lwp (lp
->ptid
.lwp ());
3692 /* Kill the fork children of any threads of inferior INF that are
3693 stopped at a fork event. */
3696 kill_unfollowed_fork_children (struct inferior
*inf
)
3698 for (thread_info
*thread
: inf
->non_exited_threads ())
3700 struct target_waitstatus
*ws
= &thread
->pending_follow
;
3702 if (ws
->kind
== TARGET_WAITKIND_FORKED
3703 || ws
->kind
== TARGET_WAITKIND_VFORKED
)
3705 ptid_t child_ptid
= ws
->value
.related_pid
;
3706 int child_pid
= child_ptid
.pid ();
3707 int child_lwp
= child_ptid
.lwp ();
3709 kill_one_lwp (child_lwp
);
3710 kill_wait_one_lwp (child_lwp
);
3712 /* Let the arch-specific native code know this process is
3714 linux_target
->low_forget_process (child_pid
);
3720 linux_nat_target::kill ()
3722 /* If we're stopped while forking and we haven't followed yet,
3723 kill the other task. We need to do this first because the
3724 parent will be sleeping if this is a vfork. */
3725 kill_unfollowed_fork_children (current_inferior ());
3727 if (forks_exist_p ())
3728 linux_fork_killall ();
3731 ptid_t ptid
= ptid_t (inferior_ptid
.pid ());
3733 /* Stop all threads before killing them, since ptrace requires
3734 that the thread is stopped to sucessfully PTRACE_KILL. */
3735 iterate_over_lwps (ptid
, stop_callback
);
3736 /* ... and wait until all of them have reported back that
3737 they're no longer running. */
3738 iterate_over_lwps (ptid
, stop_wait_callback
);
3740 /* Kill all LWP's ... */
3741 iterate_over_lwps (ptid
, kill_callback
);
3743 /* ... and wait until we've flushed all events. */
3744 iterate_over_lwps (ptid
, kill_wait_callback
);
3747 target_mourn_inferior (inferior_ptid
);
3751 linux_nat_target::mourn_inferior ()
3753 int pid
= inferior_ptid
.pid ();
3755 purge_lwp_list (pid
);
3757 if (! forks_exist_p ())
3758 /* Normal case, no other forks available. */
3759 inf_ptrace_target::mourn_inferior ();
3761 /* Multi-fork case. The current inferior_ptid has exited, but
3762 there are other viable forks to debug. Delete the exiting
3763 one and context-switch to the first available. */
3764 linux_fork_mourn_inferior ();
3766 /* Let the arch-specific native code know this process is gone. */
3767 linux_target
->low_forget_process (pid
);
3770 /* Convert a native/host siginfo object, into/from the siginfo in the
3771 layout of the inferiors' architecture. */
3774 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3776 /* If the low target didn't do anything, then just do a straight
3778 if (!linux_target
->low_siginfo_fixup (siginfo
, inf_siginfo
, direction
))
3781 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3783 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3787 static enum target_xfer_status
3788 linux_xfer_siginfo (enum target_object object
,
3789 const char *annex
, gdb_byte
*readbuf
,
3790 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3791 ULONGEST
*xfered_len
)
3795 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3797 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3798 gdb_assert (readbuf
|| writebuf
);
3800 pid
= inferior_ptid
.lwp ();
3802 pid
= inferior_ptid
.pid ();
3804 if (offset
> sizeof (siginfo
))
3805 return TARGET_XFER_E_IO
;
3808 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3810 return TARGET_XFER_E_IO
;
3812 /* When GDB is built as a 64-bit application, ptrace writes into
3813 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3814 inferior with a 64-bit GDB should look the same as debugging it
3815 with a 32-bit GDB, we need to convert it. GDB core always sees
3816 the converted layout, so any read/write will have to be done
3818 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3820 if (offset
+ len
> sizeof (siginfo
))
3821 len
= sizeof (siginfo
) - offset
;
3823 if (readbuf
!= NULL
)
3824 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3827 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3829 /* Convert back to ptrace layout before flushing it out. */
3830 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3833 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3835 return TARGET_XFER_E_IO
;
3839 return TARGET_XFER_OK
;
3842 static enum target_xfer_status
3843 linux_nat_xfer_osdata (enum target_object object
,
3844 const char *annex
, gdb_byte
*readbuf
,
3845 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3846 ULONGEST
*xfered_len
);
3848 static enum target_xfer_status
3849 linux_proc_xfer_spu (enum target_object object
,
3850 const char *annex
, gdb_byte
*readbuf
,
3851 const gdb_byte
*writebuf
,
3852 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
);
3854 static enum target_xfer_status
3855 linux_proc_xfer_partial (enum target_object object
,
3856 const char *annex
, gdb_byte
*readbuf
,
3857 const gdb_byte
*writebuf
,
3858 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
);
3860 enum target_xfer_status
3861 linux_nat_target::xfer_partial (enum target_object object
,
3862 const char *annex
, gdb_byte
*readbuf
,
3863 const gdb_byte
*writebuf
,
3864 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3866 enum target_xfer_status xfer
;
3868 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3869 return linux_xfer_siginfo (object
, annex
, readbuf
, writebuf
,
3870 offset
, len
, xfered_len
);
3872 /* The target is connected but no live inferior is selected. Pass
3873 this request down to a lower stratum (e.g., the executable
3875 if (object
== TARGET_OBJECT_MEMORY
&& inferior_ptid
== null_ptid
)
3876 return TARGET_XFER_EOF
;
3878 if (object
== TARGET_OBJECT_AUXV
)
3879 return memory_xfer_auxv (this, object
, annex
, readbuf
, writebuf
,
3880 offset
, len
, xfered_len
);
3882 if (object
== TARGET_OBJECT_OSDATA
)
3883 return linux_nat_xfer_osdata (object
, annex
, readbuf
, writebuf
,
3884 offset
, len
, xfered_len
);
3886 if (object
== TARGET_OBJECT_SPU
)
3887 return linux_proc_xfer_spu (object
, annex
, readbuf
, writebuf
,
3888 offset
, len
, xfered_len
);
3890 /* GDB calculates all addresses in the largest possible address
3892 The address width must be masked before its final use - either by
3893 linux_proc_xfer_partial or inf_ptrace_target::xfer_partial.
3895 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
3897 if (object
== TARGET_OBJECT_MEMORY
)
3899 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
3901 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
3902 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
3905 xfer
= linux_proc_xfer_partial (object
, annex
, readbuf
, writebuf
,
3906 offset
, len
, xfered_len
);
3907 if (xfer
!= TARGET_XFER_EOF
)
3910 return inf_ptrace_target::xfer_partial (object
, annex
, readbuf
, writebuf
,
3911 offset
, len
, xfered_len
);
3915 linux_nat_target::thread_alive (ptid_t ptid
)
3917 /* As long as a PTID is in lwp list, consider it alive. */
3918 return find_lwp_pid (ptid
) != NULL
;
3921 /* Implement the to_update_thread_list target method for this
3925 linux_nat_target::update_thread_list ()
3927 struct lwp_info
*lwp
;
3929 /* We add/delete threads from the list as clone/exit events are
3930 processed, so just try deleting exited threads still in the
3932 delete_exited_threads ();
3934 /* Update the processor core that each lwp/thread was last seen
3938 /* Avoid accessing /proc if the thread hasn't run since we last
3939 time we fetched the thread's core. Accessing /proc becomes
3940 noticeably expensive when we have thousands of LWPs. */
3941 if (lwp
->core
== -1)
3942 lwp
->core
= linux_common_core_of_thread (lwp
->ptid
);
3947 linux_nat_target::pid_to_str (ptid_t ptid
)
3949 static char buf
[64];
3952 && (ptid
.pid () != ptid
.lwp ()
3953 || num_lwps (ptid
.pid ()) > 1))
3955 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid
.lwp ());
3959 return normal_pid_to_str (ptid
);
3963 linux_nat_target::thread_name (struct thread_info
*thr
)
3965 return linux_proc_tid_get_name (thr
->ptid
);
3968 /* Accepts an integer PID; Returns a string representing a file that
3969 can be opened to get the symbols for the child process. */
3972 linux_nat_target::pid_to_exec_file (int pid
)
3974 return linux_proc_pid_to_exec_file (pid
);
3977 /* Implement the to_xfer_partial target method using /proc/<pid>/mem.
3978 Because we can use a single read/write call, this can be much more
3979 efficient than banging away at PTRACE_PEEKTEXT. */
3981 static enum target_xfer_status
3982 linux_proc_xfer_partial (enum target_object object
,
3983 const char *annex
, gdb_byte
*readbuf
,
3984 const gdb_byte
*writebuf
,
3985 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
3991 if (object
!= TARGET_OBJECT_MEMORY
)
3992 return TARGET_XFER_EOF
;
3994 /* Don't bother for one word. */
3995 if (len
< 3 * sizeof (long))
3996 return TARGET_XFER_EOF
;
3998 /* We could keep this file open and cache it - possibly one per
3999 thread. That requires some juggling, but is even faster. */
4000 xsnprintf (filename
, sizeof filename
, "/proc/%ld/mem",
4001 inferior_ptid
.lwp ());
4002 fd
= gdb_open_cloexec (filename
, ((readbuf
? O_RDONLY
: O_WRONLY
)
4005 return TARGET_XFER_EOF
;
4007 /* Use pread64/pwrite64 if available, since they save a syscall and can
4008 handle 64-bit offsets even on 32-bit platforms (for instance, SPARC
4009 debugging a SPARC64 application). */
4011 ret
= (readbuf
? pread64 (fd
, readbuf
, len
, offset
)
4012 : pwrite64 (fd
, writebuf
, len
, offset
));
4014 ret
= lseek (fd
, offset
, SEEK_SET
);
4016 ret
= (readbuf
? read (fd
, readbuf
, len
)
4017 : write (fd
, writebuf
, len
));
4022 if (ret
== -1 || ret
== 0)
4023 return TARGET_XFER_EOF
;
4027 return TARGET_XFER_OK
;
4032 /* Enumerate spufs IDs for process PID. */
4034 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
4036 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
4038 LONGEST written
= 0;
4041 struct dirent
*entry
;
4043 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
4044 dir
= opendir (path
);
4049 while ((entry
= readdir (dir
)) != NULL
)
4055 fd
= atoi (entry
->d_name
);
4059 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
4060 if (stat (path
, &st
) != 0)
4062 if (!S_ISDIR (st
.st_mode
))
4065 if (statfs (path
, &stfs
) != 0)
4067 if (stfs
.f_type
!= SPUFS_MAGIC
)
4070 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
4072 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
4082 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4083 object type, using the /proc file system. */
4085 static enum target_xfer_status
4086 linux_proc_xfer_spu (enum target_object object
,
4087 const char *annex
, gdb_byte
*readbuf
,
4088 const gdb_byte
*writebuf
,
4089 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
4094 int pid
= inferior_ptid
.lwp ();
4099 return TARGET_XFER_E_IO
;
4102 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4105 return TARGET_XFER_E_IO
;
4107 return TARGET_XFER_EOF
;
4110 *xfered_len
= (ULONGEST
) l
;
4111 return TARGET_XFER_OK
;
4116 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4117 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4119 return TARGET_XFER_E_IO
;
4122 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4125 return TARGET_XFER_EOF
;
4129 ret
= write (fd
, writebuf
, (size_t) len
);
4131 ret
= read (fd
, readbuf
, (size_t) len
);
4136 return TARGET_XFER_E_IO
;
4138 return TARGET_XFER_EOF
;
4141 *xfered_len
= (ULONGEST
) ret
;
4142 return TARGET_XFER_OK
;
4147 /* Parse LINE as a signal set and add its set bits to SIGS. */
4150 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4152 int len
= strlen (line
) - 1;
4156 if (line
[len
] != '\n')
4157 error (_("Could not parse signal set: %s"), line
);
4165 if (*p
>= '0' && *p
<= '9')
4167 else if (*p
>= 'a' && *p
<= 'f')
4168 digit
= *p
- 'a' + 10;
4170 error (_("Could not parse signal set: %s"), line
);
4175 sigaddset (sigs
, signum
+ 1);
4177 sigaddset (sigs
, signum
+ 2);
4179 sigaddset (sigs
, signum
+ 3);
4181 sigaddset (sigs
, signum
+ 4);
4187 /* Find process PID's pending signals from /proc/pid/status and set
4191 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4192 sigset_t
*blocked
, sigset_t
*ignored
)
4194 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4196 sigemptyset (pending
);
4197 sigemptyset (blocked
);
4198 sigemptyset (ignored
);
4199 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4200 gdb_file_up procfile
= gdb_fopen_cloexec (fname
, "r");
4201 if (procfile
== NULL
)
4202 error (_("Could not open %s"), fname
);
4204 while (fgets (buffer
, PATH_MAX
, procfile
.get ()) != NULL
)
4206 /* Normal queued signals are on the SigPnd line in the status
4207 file. However, 2.6 kernels also have a "shared" pending
4208 queue for delivering signals to a thread group, so check for
4211 Unfortunately some Red Hat kernels include the shared pending
4212 queue but not the ShdPnd status field. */
4214 if (startswith (buffer
, "SigPnd:\t"))
4215 add_line_to_sigset (buffer
+ 8, pending
);
4216 else if (startswith (buffer
, "ShdPnd:\t"))
4217 add_line_to_sigset (buffer
+ 8, pending
);
4218 else if (startswith (buffer
, "SigBlk:\t"))
4219 add_line_to_sigset (buffer
+ 8, blocked
);
4220 else if (startswith (buffer
, "SigIgn:\t"))
4221 add_line_to_sigset (buffer
+ 8, ignored
);
4225 static enum target_xfer_status
4226 linux_nat_xfer_osdata (enum target_object object
,
4227 const char *annex
, gdb_byte
*readbuf
,
4228 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4229 ULONGEST
*xfered_len
)
4231 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4233 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4234 if (*xfered_len
== 0)
4235 return TARGET_XFER_EOF
;
4237 return TARGET_XFER_OK
;
4240 std::vector
<static_tracepoint_marker
>
4241 linux_nat_target::static_tracepoint_markers_by_strid (const char *strid
)
4243 char s
[IPA_CMD_BUF_SIZE
];
4244 int pid
= inferior_ptid
.pid ();
4245 std::vector
<static_tracepoint_marker
> markers
;
4247 ptid_t ptid
= ptid_t (pid
, 0, 0);
4248 static_tracepoint_marker marker
;
4253 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4254 s
[sizeof ("qTfSTM")] = 0;
4256 agent_run_command (pid
, s
, strlen (s
) + 1);
4259 SCOPE_EXIT
{ target_continue_no_signal (ptid
); };
4265 parse_static_tracepoint_marker_definition (p
, &p
, &marker
);
4267 if (strid
== NULL
|| marker
.str_id
== strid
)
4268 markers
.push_back (std::move (marker
));
4270 while (*p
++ == ','); /* comma-separated list */
4272 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4273 s
[sizeof ("qTsSTM")] = 0;
4274 agent_run_command (pid
, s
, strlen (s
) + 1);
4281 /* target_is_async_p implementation. */
4284 linux_nat_target::is_async_p ()
4286 return linux_is_async_p ();
4289 /* target_can_async_p implementation. */
4292 linux_nat_target::can_async_p ()
4294 /* We're always async, unless the user explicitly prevented it with the
4295 "maint set target-async" command. */
4296 return target_async_permitted
;
4300 linux_nat_target::supports_non_stop ()
4305 /* to_always_non_stop_p implementation. */
4308 linux_nat_target::always_non_stop_p ()
4313 /* True if we want to support multi-process. To be removed when GDB
4314 supports multi-exec. */
4316 int linux_multi_process
= 1;
4319 linux_nat_target::supports_multi_process ()
4321 return linux_multi_process
;
4325 linux_nat_target::supports_disable_randomization ()
4327 #ifdef HAVE_PERSONALITY
4334 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4335 so we notice when any child changes state, and notify the
4336 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4337 above to wait for the arrival of a SIGCHLD. */
4340 sigchld_handler (int signo
)
4342 int old_errno
= errno
;
4344 if (debug_linux_nat
)
4345 ui_file_write_async_safe (gdb_stdlog
,
4346 "sigchld\n", sizeof ("sigchld\n") - 1);
4348 if (signo
== SIGCHLD
4349 && linux_nat_event_pipe
[0] != -1)
4350 async_file_mark (); /* Let the event loop know that there are
4351 events to handle. */
4356 /* Callback registered with the target events file descriptor. */
4359 handle_target_event (int error
, gdb_client_data client_data
)
4361 inferior_event_handler (INF_REG_EVENT
, NULL
);
4364 /* Create/destroy the target events pipe. Returns previous state. */
4367 linux_async_pipe (int enable
)
4369 int previous
= linux_is_async_p ();
4371 if (previous
!= enable
)
4375 /* Block child signals while we create/destroy the pipe, as
4376 their handler writes to it. */
4377 block_child_signals (&prev_mask
);
4381 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4382 internal_error (__FILE__
, __LINE__
,
4383 "creating event pipe failed.");
4385 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4386 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4390 close (linux_nat_event_pipe
[0]);
4391 close (linux_nat_event_pipe
[1]);
4392 linux_nat_event_pipe
[0] = -1;
4393 linux_nat_event_pipe
[1] = -1;
4396 restore_child_signals_mask (&prev_mask
);
4402 /* target_async implementation. */
4405 linux_nat_target::async (int enable
)
4409 if (!linux_async_pipe (1))
4411 add_file_handler (linux_nat_event_pipe
[0],
4412 handle_target_event
, NULL
);
4413 /* There may be pending events to handle. Tell the event loop
4420 delete_file_handler (linux_nat_event_pipe
[0]);
4421 linux_async_pipe (0);
4426 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4430 linux_nat_stop_lwp (struct lwp_info
*lwp
)
4434 if (debug_linux_nat
)
4435 fprintf_unfiltered (gdb_stdlog
,
4436 "LNSL: running -> suspending %s\n",
4437 target_pid_to_str (lwp
->ptid
));
4440 if (lwp
->last_resume_kind
== resume_stop
)
4442 if (debug_linux_nat
)
4443 fprintf_unfiltered (gdb_stdlog
,
4444 "linux-nat: already stopping LWP %ld at "
4450 stop_callback (lwp
);
4451 lwp
->last_resume_kind
= resume_stop
;
4455 /* Already known to be stopped; do nothing. */
4457 if (debug_linux_nat
)
4459 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4460 fprintf_unfiltered (gdb_stdlog
,
4461 "LNSL: already stopped/stop_requested %s\n",
4462 target_pid_to_str (lwp
->ptid
));
4464 fprintf_unfiltered (gdb_stdlog
,
4465 "LNSL: already stopped/no "
4466 "stop_requested yet %s\n",
4467 target_pid_to_str (lwp
->ptid
));
4474 linux_nat_target::stop (ptid_t ptid
)
4476 iterate_over_lwps (ptid
, linux_nat_stop_lwp
);
4480 linux_nat_target::close ()
4482 /* Unregister from the event loop. */
4486 inf_ptrace_target::close ();
4489 /* When requests are passed down from the linux-nat layer to the
4490 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4491 used. The address space pointer is stored in the inferior object,
4492 but the common code that is passed such ptid can't tell whether
4493 lwpid is a "main" process id or not (it assumes so). We reverse
4494 look up the "main" process id from the lwp here. */
4496 struct address_space
*
4497 linux_nat_target::thread_address_space (ptid_t ptid
)
4499 struct lwp_info
*lwp
;
4500 struct inferior
*inf
;
4503 if (ptid
.lwp () == 0)
4505 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4507 lwp
= find_lwp_pid (ptid
);
4508 pid
= lwp
->ptid
.pid ();
4512 /* A (pid,lwpid,0) ptid. */
4516 inf
= find_inferior_pid (pid
);
4517 gdb_assert (inf
!= NULL
);
4521 /* Return the cached value of the processor core for thread PTID. */
4524 linux_nat_target::core_of_thread (ptid_t ptid
)
4526 struct lwp_info
*info
= find_lwp_pid (ptid
);
4533 /* Implementation of to_filesystem_is_local. */
4536 linux_nat_target::filesystem_is_local ()
4538 struct inferior
*inf
= current_inferior ();
4540 if (inf
->fake_pid_p
|| inf
->pid
== 0)
4543 return linux_ns_same (inf
->pid
, LINUX_NS_MNT
);
4546 /* Convert the INF argument passed to a to_fileio_* method
4547 to a process ID suitable for passing to its corresponding
4548 linux_mntns_* function. If INF is non-NULL then the
4549 caller is requesting the filesystem seen by INF. If INF
4550 is NULL then the caller is requesting the filesystem seen
4551 by the GDB. We fall back to GDB's filesystem in the case
4552 that INF is non-NULL but its PID is unknown. */
4555 linux_nat_fileio_pid_of (struct inferior
*inf
)
4557 if (inf
== NULL
|| inf
->fake_pid_p
|| inf
->pid
== 0)
4563 /* Implementation of to_fileio_open. */
4566 linux_nat_target::fileio_open (struct inferior
*inf
, const char *filename
,
4567 int flags
, int mode
, int warn_if_slow
,
4574 if (fileio_to_host_openflags (flags
, &nat_flags
) == -1
4575 || fileio_to_host_mode (mode
, &nat_mode
) == -1)
4577 *target_errno
= FILEIO_EINVAL
;
4581 fd
= linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf
),
4582 filename
, nat_flags
, nat_mode
);
4584 *target_errno
= host_to_fileio_error (errno
);
4589 /* Implementation of to_fileio_readlink. */
4591 gdb::optional
<std::string
>
4592 linux_nat_target::fileio_readlink (struct inferior
*inf
, const char *filename
,
4598 len
= linux_mntns_readlink (linux_nat_fileio_pid_of (inf
),
4599 filename
, buf
, sizeof (buf
));
4602 *target_errno
= host_to_fileio_error (errno
);
4606 return std::string (buf
, len
);
4609 /* Implementation of to_fileio_unlink. */
4612 linux_nat_target::fileio_unlink (struct inferior
*inf
, const char *filename
,
4617 ret
= linux_mntns_unlink (linux_nat_fileio_pid_of (inf
),
4620 *target_errno
= host_to_fileio_error (errno
);
4625 /* Implementation of the to_thread_events method. */
4628 linux_nat_target::thread_events (int enable
)
4630 report_thread_events
= enable
;
4633 linux_nat_target::linux_nat_target ()
4635 /* We don't change the stratum; this target will sit at
4636 process_stratum and thread_db will set at thread_stratum. This
4637 is a little strange, since this is a multi-threaded-capable
4638 target, but we want to be on the stack below thread_db, and we
4639 also want to be used for single-threaded processes. */
4642 /* See linux-nat.h. */
4645 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4654 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4657 memset (siginfo
, 0, sizeof (*siginfo
));
4663 /* See nat/linux-nat.h. */
4666 current_lwp_ptid (void)
4668 gdb_assert (inferior_ptid
.lwp_p ());
4669 return inferior_ptid
;
4673 _initialize_linux_nat (void)
4675 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4676 &debug_linux_nat
, _("\
4677 Set debugging of GNU/Linux lwp module."), _("\
4678 Show debugging of GNU/Linux lwp module."), _("\
4679 Enables printf debugging output."),
4681 show_debug_linux_nat
,
4682 &setdebuglist
, &showdebuglist
);
4684 add_setshow_boolean_cmd ("linux-namespaces", class_maintenance
,
4685 &debug_linux_namespaces
, _("\
4686 Set debugging of GNU/Linux namespaces module."), _("\
4687 Show debugging of GNU/Linux namespaces module."), _("\
4688 Enables printf debugging output."),
4691 &setdebuglist
, &showdebuglist
);
4693 /* Save this mask as the default. */
4694 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
4696 /* Install a SIGCHLD handler. */
4697 sigchld_action
.sa_handler
= sigchld_handler
;
4698 sigemptyset (&sigchld_action
.sa_mask
);
4699 sigchld_action
.sa_flags
= SA_RESTART
;
4701 /* Make it the default. */
4702 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4704 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4705 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4706 sigdelset (&suspend_mask
, SIGCHLD
);
4708 sigemptyset (&blocked_mask
);
4710 lwp_lwpid_htab_create ();
4714 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4715 the GNU/Linux Threads library and therefore doesn't really belong
4718 /* Return the set of signals used by the threads library in *SET. */
4721 lin_thread_get_thread_signals (sigset_t
*set
)
4725 /* NPTL reserves the first two RT signals, but does not provide any
4726 way for the debugger to query the signal numbers - fortunately
4727 they don't change. */
4728 sigaddset (set
, __SIGRTMIN
);
4729 sigaddset (set
, __SIGRTMIN
+ 1);