1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2020 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
26 #include "gdbsupport/gdb_wait.h"
28 #include <sys/syscall.h>
29 #include "nat/gdb_ptrace.h"
30 #include "linux-nat.h"
31 #include "nat/linux-ptrace.h"
32 #include "nat/linux-procfs.h"
33 #include "nat/linux-personality.h"
34 #include "linux-fork.h"
35 #include "gdbthread.h"
39 #include "inf-child.h"
40 #include "inf-ptrace.h"
42 #include <sys/procfs.h> /* for elf_gregset etc. */
43 #include "elf-bfd.h" /* for elfcore_write_* */
44 #include "gregset.h" /* for gregset */
45 #include "gdbcore.h" /* for get_exec_file */
46 #include <ctype.h> /* for isdigit */
47 #include <sys/stat.h> /* for struct stat */
48 #include <fcntl.h> /* for O_RDONLY */
50 #include "event-loop.h"
51 #include "event-top.h"
53 #include <sys/types.h>
55 #include "xml-support.h"
58 #include "nat/linux-osdata.h"
59 #include "linux-tdep.h"
61 #include "gdbsupport/agent.h"
62 #include "tracepoint.h"
63 #include "gdbsupport/buffer.h"
64 #include "target-descriptions.h"
65 #include "gdbsupport/filestuff.h"
67 #include "nat/linux-namespaces.h"
68 #include "gdbsupport/fileio.h"
69 #include "gdbsupport/scope-exit.h"
70 #include "gdbsupport/gdb-sigmask.h"
72 /* This comment documents high-level logic of this file.
74 Waiting for events in sync mode
75 ===============================
77 When waiting for an event in a specific thread, we just use waitpid,
78 passing the specific pid, and not passing WNOHANG.
80 When waiting for an event in all threads, waitpid is not quite good:
82 - If the thread group leader exits while other threads in the thread
83 group still exist, waitpid(TGID, ...) hangs. That waitpid won't
84 return an exit status until the other threads in the group are
87 - When a non-leader thread execs, that thread just vanishes without
88 reporting an exit (so we'd hang if we waited for it explicitly in
89 that case). The exec event is instead reported to the TGID pid.
91 The solution is to always use -1 and WNOHANG, together with
94 First, we use non-blocking waitpid to check for events. If nothing is
95 found, we use sigsuspend to wait for SIGCHLD. When SIGCHLD arrives,
96 it means something happened to a child process. As soon as we know
97 there's an event, we get back to calling nonblocking waitpid.
99 Note that SIGCHLD should be blocked between waitpid and sigsuspend
100 calls, so that we don't miss a signal. If SIGCHLD arrives in between,
101 when it's blocked, the signal becomes pending and sigsuspend
102 immediately notices it and returns.
104 Waiting for events in async mode (TARGET_WNOHANG)
105 =================================================
107 In async mode, GDB should always be ready to handle both user input
108 and target events, so neither blocking waitpid nor sigsuspend are
109 viable options. Instead, we should asynchronously notify the GDB main
110 event loop whenever there's an unprocessed event from the target. We
111 detect asynchronous target events by handling SIGCHLD signals. To
112 notify the event loop about target events, the self-pipe trick is used
113 --- a pipe is registered as waitable event source in the event loop,
114 the event loop select/poll's on the read end of this pipe (as well on
115 other event sources, e.g., stdin), and the SIGCHLD handler writes a
116 byte to this pipe. This is more portable than relying on
117 pselect/ppoll, since on kernels that lack those syscalls, libc
118 emulates them with select/poll+sigprocmask, and that is racy
119 (a.k.a. plain broken).
121 Obviously, if we fail to notify the event loop if there's a target
122 event, it's bad. OTOH, if we notify the event loop when there's no
123 event from the target, linux_nat_wait will detect that there's no real
124 event to report, and return event of type TARGET_WAITKIND_IGNORE.
125 This is mostly harmless, but it will waste time and is better avoided.
127 The main design point is that every time GDB is outside linux-nat.c,
128 we have a SIGCHLD handler installed that is called when something
129 happens to the target and notifies the GDB event loop. Whenever GDB
130 core decides to handle the event, and calls into linux-nat.c, we
131 process things as in sync mode, except that the we never block in
134 While processing an event, we may end up momentarily blocked in
135 waitpid calls. Those waitpid calls, while blocking, are guarantied to
136 return quickly. E.g., in all-stop mode, before reporting to the core
137 that an LWP hit a breakpoint, all LWPs are stopped by sending them
138 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
139 Note that this is different from blocking indefinitely waiting for the
140 next event --- here, we're already handling an event.
145 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
146 signal is not entirely significant; we just need for a signal to be delivered,
147 so that we can intercept it. SIGSTOP's advantage is that it can not be
148 blocked. A disadvantage is that it is not a real-time signal, so it can only
149 be queued once; we do not keep track of other sources of SIGSTOP.
151 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
152 use them, because they have special behavior when the signal is generated -
153 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
154 kills the entire thread group.
156 A delivered SIGSTOP would stop the entire thread group, not just the thread we
157 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
158 cancel it (by PTRACE_CONT without passing SIGSTOP).
160 We could use a real-time signal instead. This would solve those problems; we
161 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
162 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
163 generates it, and there are races with trying to find a signal that is not
169 The case of a thread group (process) with 3 or more threads, and a
170 thread other than the leader execs is worth detailing:
172 On an exec, the Linux kernel destroys all threads except the execing
173 one in the thread group, and resets the execing thread's tid to the
174 tgid. No exit notification is sent for the execing thread -- from the
175 ptracer's perspective, it appears as though the execing thread just
176 vanishes. Until we reap all other threads except the leader and the
177 execing thread, the leader will be zombie, and the execing thread will
178 be in `D (disc sleep)' state. As soon as all other threads are
179 reaped, the execing thread changes its tid to the tgid, and the
180 previous (zombie) leader vanishes, giving place to the "new"
184 #define O_LARGEFILE 0
187 struct linux_nat_target
*linux_target
;
189 /* Does the current host support PTRACE_GETREGSET? */
190 enum tribool have_ptrace_getregset
= TRIBOOL_UNKNOWN
;
192 static unsigned int debug_linux_nat
;
194 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
195 struct cmd_list_element
*c
, const char *value
)
197 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
201 struct simple_pid_list
205 struct simple_pid_list
*next
;
207 struct simple_pid_list
*stopped_pids
;
209 /* Whether target_thread_events is in effect. */
210 static int report_thread_events
;
212 /* Async mode support. */
214 /* The read/write ends of the pipe registered as waitable file in the
216 static int linux_nat_event_pipe
[2] = { -1, -1 };
218 /* True if we're currently in async mode. */
219 #define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
221 /* Flush the event pipe. */
224 async_file_flush (void)
231 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
233 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
236 /* Put something (anything, doesn't matter what, or how much) in event
237 pipe, so that the select/poll in the event-loop realizes we have
238 something to process. */
241 async_file_mark (void)
245 /* It doesn't really matter what the pipe contains, as long we end
246 up with something in it. Might as well flush the previous
252 ret
= write (linux_nat_event_pipe
[1], "+", 1);
254 while (ret
== -1 && errno
== EINTR
);
256 /* Ignore EAGAIN. If the pipe is full, the event loop will already
257 be awakened anyway. */
260 static int kill_lwp (int lwpid
, int signo
);
262 static int stop_callback (struct lwp_info
*lp
);
264 static void block_child_signals (sigset_t
*prev_mask
);
265 static void restore_child_signals_mask (sigset_t
*prev_mask
);
268 static struct lwp_info
*add_lwp (ptid_t ptid
);
269 static void purge_lwp_list (int pid
);
270 static void delete_lwp (ptid_t ptid
);
271 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
273 static int lwp_status_pending_p (struct lwp_info
*lp
);
275 static void save_stop_reason (struct lwp_info
*lp
);
280 /* See nat/linux-nat.h. */
283 ptid_of_lwp (struct lwp_info
*lwp
)
288 /* See nat/linux-nat.h. */
291 lwp_set_arch_private_info (struct lwp_info
*lwp
,
292 struct arch_lwp_info
*info
)
294 lwp
->arch_private
= info
;
297 /* See nat/linux-nat.h. */
299 struct arch_lwp_info
*
300 lwp_arch_private_info (struct lwp_info
*lwp
)
302 return lwp
->arch_private
;
305 /* See nat/linux-nat.h. */
308 lwp_is_stopped (struct lwp_info
*lwp
)
313 /* See nat/linux-nat.h. */
315 enum target_stop_reason
316 lwp_stop_reason (struct lwp_info
*lwp
)
318 return lwp
->stop_reason
;
321 /* See nat/linux-nat.h. */
324 lwp_is_stepping (struct lwp_info
*lwp
)
330 /* Trivial list manipulation functions to keep track of a list of
331 new stopped processes. */
333 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
335 struct simple_pid_list
*new_pid
= XNEW (struct simple_pid_list
);
338 new_pid
->status
= status
;
339 new_pid
->next
= *listp
;
344 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
346 struct simple_pid_list
**p
;
348 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
349 if ((*p
)->pid
== pid
)
351 struct simple_pid_list
*next
= (*p
)->next
;
353 *statusp
= (*p
)->status
;
361 /* Return the ptrace options that we want to try to enable. */
364 linux_nat_ptrace_options (int attached
)
369 options
|= PTRACE_O_EXITKILL
;
371 options
|= (PTRACE_O_TRACESYSGOOD
372 | PTRACE_O_TRACEVFORKDONE
373 | PTRACE_O_TRACEVFORK
375 | PTRACE_O_TRACEEXEC
);
380 /* Initialize ptrace and procfs warnings and check for supported
381 ptrace features given PID.
383 ATTACHED should be nonzero iff we attached to the inferior. */
386 linux_init_ptrace_procfs (pid_t pid
, int attached
)
388 int options
= linux_nat_ptrace_options (attached
);
390 linux_enable_event_reporting (pid
, options
);
391 linux_ptrace_init_warnings ();
392 linux_proc_init_warnings ();
395 linux_nat_target::~linux_nat_target ()
399 linux_nat_target::post_attach (int pid
)
401 linux_init_ptrace_procfs (pid
, 1);
405 linux_nat_target::post_startup_inferior (ptid_t ptid
)
407 linux_init_ptrace_procfs (ptid
.pid (), 0);
410 /* Return the number of known LWPs in the tgid given by PID. */
418 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
419 if (lp
->ptid
.pid () == pid
)
425 /* Deleter for lwp_info unique_ptr specialisation. */
429 void operator() (struct lwp_info
*lwp
) const
431 delete_lwp (lwp
->ptid
);
435 /* A unique_ptr specialisation for lwp_info. */
437 typedef std::unique_ptr
<struct lwp_info
, lwp_deleter
> lwp_info_up
;
439 /* Target hook for follow_fork. On entry inferior_ptid must be the
440 ptid of the followed inferior. At return, inferior_ptid will be
444 linux_nat_target::follow_fork (int follow_child
, int detach_fork
)
448 struct lwp_info
*child_lp
= NULL
;
450 ptid_t parent_ptid
, child_ptid
;
451 int parent_pid
, child_pid
;
453 has_vforked
= (inferior_thread ()->pending_follow
.kind
454 == TARGET_WAITKIND_VFORKED
);
455 parent_ptid
= inferior_ptid
;
456 child_ptid
= inferior_thread ()->pending_follow
.value
.related_pid
;
457 parent_pid
= parent_ptid
.lwp ();
458 child_pid
= child_ptid
.lwp ();
460 /* We're already attached to the parent, by default. */
461 child_lp
= add_lwp (child_ptid
);
462 child_lp
->stopped
= 1;
463 child_lp
->last_resume_kind
= resume_stop
;
465 /* Detach new forked process? */
468 int child_stop_signal
= 0;
469 bool detach_child
= true;
471 /* Move CHILD_LP into a unique_ptr and clear the source pointer
472 to prevent us doing anything stupid with it. */
473 lwp_info_up
child_lp_ptr (child_lp
);
476 linux_target
->low_prepare_to_resume (child_lp_ptr
.get ());
478 /* When debugging an inferior in an architecture that supports
479 hardware single stepping on a kernel without commit
480 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
481 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
482 set if the parent process had them set.
483 To work around this, single step the child process
484 once before detaching to clear the flags. */
486 /* Note that we consult the parent's architecture instead of
487 the child's because there's no inferior for the child at
489 if (!gdbarch_software_single_step_p (target_thread_architecture
494 linux_disable_event_reporting (child_pid
);
495 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
496 perror_with_name (_("Couldn't do single step"));
497 if (my_waitpid (child_pid
, &status
, 0) < 0)
498 perror_with_name (_("Couldn't wait vfork process"));
501 detach_child
= WIFSTOPPED (status
);
502 child_stop_signal
= WSTOPSIG (status
);
508 int signo
= child_stop_signal
;
511 && !signal_pass_state (gdb_signal_from_host (signo
)))
513 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
518 scoped_restore save_inferior_ptid
519 = make_scoped_restore (&inferior_ptid
);
520 inferior_ptid
= child_ptid
;
522 /* Let the thread_db layer learn about this new process. */
523 check_for_thread_db ();
528 struct lwp_info
*parent_lp
;
530 parent_lp
= find_lwp_pid (parent_ptid
);
531 gdb_assert (linux_supports_tracefork () >= 0);
533 if (linux_supports_tracevforkdone ())
536 fprintf_unfiltered (gdb_stdlog
,
537 "LCFF: waiting for VFORK_DONE on %d\n",
539 parent_lp
->stopped
= 1;
541 /* We'll handle the VFORK_DONE event like any other
542 event, in target_wait. */
546 /* We can't insert breakpoints until the child has
547 finished with the shared memory region. We need to
548 wait until that happens. Ideal would be to just
550 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
551 - waitpid (parent_pid, &status, __WALL);
552 However, most architectures can't handle a syscall
553 being traced on the way out if it wasn't traced on
556 We might also think to loop, continuing the child
557 until it exits or gets a SIGTRAP. One problem is
558 that the child might call ptrace with PTRACE_TRACEME.
560 There's no simple and reliable way to figure out when
561 the vforked child will be done with its copy of the
562 shared memory. We could step it out of the syscall,
563 two instructions, let it go, and then single-step the
564 parent once. When we have hardware single-step, this
565 would work; with software single-step it could still
566 be made to work but we'd have to be able to insert
567 single-step breakpoints in the child, and we'd have
568 to insert -just- the single-step breakpoint in the
569 parent. Very awkward.
571 In the end, the best we can do is to make sure it
572 runs for a little while. Hopefully it will be out of
573 range of any breakpoints we reinsert. Usually this
574 is only the single-step breakpoint at vfork's return
578 fprintf_unfiltered (gdb_stdlog
,
579 "LCFF: no VFORK_DONE "
580 "support, sleeping a bit\n");
584 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
585 and leave it pending. The next linux_nat_resume call
586 will notice a pending event, and bypasses actually
587 resuming the inferior. */
588 parent_lp
->status
= 0;
589 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
590 parent_lp
->stopped
= 1;
592 /* If we're in async mode, need to tell the event loop
593 there's something here to process. */
594 if (target_is_async_p ())
601 struct lwp_info
*child_lp
;
603 child_lp
= add_lwp (inferior_ptid
);
604 child_lp
->stopped
= 1;
605 child_lp
->last_resume_kind
= resume_stop
;
607 /* Let the thread_db layer learn about this new process. */
608 check_for_thread_db ();
616 linux_nat_target::insert_fork_catchpoint (int pid
)
618 return !linux_supports_tracefork ();
622 linux_nat_target::remove_fork_catchpoint (int pid
)
628 linux_nat_target::insert_vfork_catchpoint (int pid
)
630 return !linux_supports_tracefork ();
634 linux_nat_target::remove_vfork_catchpoint (int pid
)
640 linux_nat_target::insert_exec_catchpoint (int pid
)
642 return !linux_supports_tracefork ();
646 linux_nat_target::remove_exec_catchpoint (int pid
)
652 linux_nat_target::set_syscall_catchpoint (int pid
, bool needed
, int any_count
,
653 gdb::array_view
<const int> syscall_counts
)
655 if (!linux_supports_tracesysgood ())
658 /* On GNU/Linux, we ignore the arguments. It means that we only
659 enable the syscall catchpoints, but do not disable them.
661 Also, we do not use the `syscall_counts' information because we do not
662 filter system calls here. We let GDB do the logic for us. */
666 /* List of known LWPs, keyed by LWP PID. This speeds up the common
667 case of mapping a PID returned from the kernel to our corresponding
668 lwp_info data structure. */
669 static htab_t lwp_lwpid_htab
;
671 /* Calculate a hash from a lwp_info's LWP PID. */
674 lwp_info_hash (const void *ap
)
676 const struct lwp_info
*lp
= (struct lwp_info
*) ap
;
677 pid_t pid
= lp
->ptid
.lwp ();
679 return iterative_hash_object (pid
, 0);
682 /* Equality function for the lwp_info hash table. Compares the LWP's
686 lwp_lwpid_htab_eq (const void *a
, const void *b
)
688 const struct lwp_info
*entry
= (const struct lwp_info
*) a
;
689 const struct lwp_info
*element
= (const struct lwp_info
*) b
;
691 return entry
->ptid
.lwp () == element
->ptid
.lwp ();
694 /* Create the lwp_lwpid_htab hash table. */
697 lwp_lwpid_htab_create (void)
699 lwp_lwpid_htab
= htab_create (100, lwp_info_hash
, lwp_lwpid_htab_eq
, NULL
);
702 /* Add LP to the hash table. */
705 lwp_lwpid_htab_add_lwp (struct lwp_info
*lp
)
709 slot
= htab_find_slot (lwp_lwpid_htab
, lp
, INSERT
);
710 gdb_assert (slot
!= NULL
&& *slot
== NULL
);
714 /* Head of doubly-linked list of known LWPs. Sorted by reverse
715 creation order. This order is assumed in some cases. E.g.,
716 reaping status after killing alls lwps of a process: the leader LWP
717 must be reaped last. */
718 struct lwp_info
*lwp_list
;
720 /* Add LP to sorted-by-reverse-creation-order doubly-linked list. */
723 lwp_list_add (struct lwp_info
*lp
)
726 if (lwp_list
!= NULL
)
731 /* Remove LP from sorted-by-reverse-creation-order doubly-linked
735 lwp_list_remove (struct lwp_info
*lp
)
737 /* Remove from sorted-by-creation-order list. */
738 if (lp
->next
!= NULL
)
739 lp
->next
->prev
= lp
->prev
;
740 if (lp
->prev
!= NULL
)
741 lp
->prev
->next
= lp
->next
;
748 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
749 _initialize_linux_nat. */
750 static sigset_t suspend_mask
;
752 /* Signals to block to make that sigsuspend work. */
753 static sigset_t blocked_mask
;
755 /* SIGCHLD action. */
756 struct sigaction sigchld_action
;
758 /* Block child signals (SIGCHLD and linux threads signals), and store
759 the previous mask in PREV_MASK. */
762 block_child_signals (sigset_t
*prev_mask
)
764 /* Make sure SIGCHLD is blocked. */
765 if (!sigismember (&blocked_mask
, SIGCHLD
))
766 sigaddset (&blocked_mask
, SIGCHLD
);
768 gdb_sigmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
771 /* Restore child signals mask, previously returned by
772 block_child_signals. */
775 restore_child_signals_mask (sigset_t
*prev_mask
)
777 gdb_sigmask (SIG_SETMASK
, prev_mask
, NULL
);
780 /* Mask of signals to pass directly to the inferior. */
781 static sigset_t pass_mask
;
783 /* Update signals to pass to the inferior. */
785 linux_nat_target::pass_signals
786 (gdb::array_view
<const unsigned char> pass_signals
)
790 sigemptyset (&pass_mask
);
792 for (signo
= 1; signo
< NSIG
; signo
++)
794 int target_signo
= gdb_signal_from_host (signo
);
795 if (target_signo
< pass_signals
.size () && pass_signals
[target_signo
])
796 sigaddset (&pass_mask
, signo
);
802 /* Prototypes for local functions. */
803 static int stop_wait_callback (struct lwp_info
*lp
);
804 static int resume_stopped_resumed_lwps (struct lwp_info
*lp
, const ptid_t wait_ptid
);
805 static int check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
);
809 /* Destroy and free LP. */
812 lwp_free (struct lwp_info
*lp
)
814 /* Let the arch specific bits release arch_lwp_info. */
815 linux_target
->low_delete_thread (lp
->arch_private
);
820 /* Traversal function for purge_lwp_list. */
823 lwp_lwpid_htab_remove_pid (void **slot
, void *info
)
825 struct lwp_info
*lp
= (struct lwp_info
*) *slot
;
826 int pid
= *(int *) info
;
828 if (lp
->ptid
.pid () == pid
)
830 htab_clear_slot (lwp_lwpid_htab
, slot
);
831 lwp_list_remove (lp
);
838 /* Remove all LWPs belong to PID from the lwp list. */
841 purge_lwp_list (int pid
)
843 htab_traverse_noresize (lwp_lwpid_htab
, lwp_lwpid_htab_remove_pid
, &pid
);
846 /* Add the LWP specified by PTID to the list. PTID is the first LWP
847 in the process. Return a pointer to the structure describing the
850 This differs from add_lwp in that we don't let the arch specific
851 bits know about this new thread. Current clients of this callback
852 take the opportunity to install watchpoints in the new thread, and
853 we shouldn't do that for the first thread. If we're spawning a
854 child ("run"), the thread executes the shell wrapper first, and we
855 shouldn't touch it until it execs the program we want to debug.
856 For "attach", it'd be okay to call the callback, but it's not
857 necessary, because watchpoints can't yet have been inserted into
860 static struct lwp_info
*
861 add_initial_lwp (ptid_t ptid
)
865 gdb_assert (ptid
.lwp_p ());
867 lp
= XNEW (struct lwp_info
);
869 memset (lp
, 0, sizeof (struct lwp_info
));
871 lp
->last_resume_kind
= resume_continue
;
872 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
877 /* Add to sorted-by-reverse-creation-order list. */
880 /* Add to keyed-by-pid htab. */
881 lwp_lwpid_htab_add_lwp (lp
);
886 /* Add the LWP specified by PID to the list. Return a pointer to the
887 structure describing the new LWP. The LWP should already be
890 static struct lwp_info
*
891 add_lwp (ptid_t ptid
)
895 lp
= add_initial_lwp (ptid
);
897 /* Let the arch specific bits know about this new thread. Current
898 clients of this callback take the opportunity to install
899 watchpoints in the new thread. We don't do this for the first
900 thread though. See add_initial_lwp. */
901 linux_target
->low_new_thread (lp
);
906 /* Remove the LWP specified by PID from the list. */
909 delete_lwp (ptid_t ptid
)
913 struct lwp_info dummy
;
916 slot
= htab_find_slot (lwp_lwpid_htab
, &dummy
, NO_INSERT
);
920 lp
= *(struct lwp_info
**) slot
;
921 gdb_assert (lp
!= NULL
);
923 htab_clear_slot (lwp_lwpid_htab
, slot
);
925 /* Remove from sorted-by-creation-order list. */
926 lwp_list_remove (lp
);
932 /* Return a pointer to the structure describing the LWP corresponding
933 to PID. If no corresponding LWP could be found, return NULL. */
935 static struct lwp_info
*
936 find_lwp_pid (ptid_t ptid
)
940 struct lwp_info dummy
;
947 dummy
.ptid
= ptid_t (0, lwp
, 0);
948 lp
= (struct lwp_info
*) htab_find (lwp_lwpid_htab
, &dummy
);
952 /* See nat/linux-nat.h. */
955 iterate_over_lwps (ptid_t filter
,
956 gdb::function_view
<iterate_over_lwps_ftype
> callback
)
958 struct lwp_info
*lp
, *lpnext
;
960 for (lp
= lwp_list
; lp
; lp
= lpnext
)
964 if (lp
->ptid
.matches (filter
))
966 if (callback (lp
) != 0)
974 /* Update our internal state when changing from one checkpoint to
975 another indicated by NEW_PTID. We can only switch single-threaded
976 applications, so we only create one new LWP, and the previous list
980 linux_nat_switch_fork (ptid_t new_ptid
)
984 purge_lwp_list (inferior_ptid
.pid ());
986 lp
= add_lwp (new_ptid
);
989 /* This changes the thread's ptid while preserving the gdb thread
990 num. Also changes the inferior pid, while preserving the
992 thread_change_ptid (inferior_ptid
, new_ptid
);
994 /* We've just told GDB core that the thread changed target id, but,
995 in fact, it really is a different thread, with different register
997 registers_changed ();
1000 /* Handle the exit of a single thread LP. */
1003 exit_lwp (struct lwp_info
*lp
)
1005 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1009 if (print_thread_events
)
1010 printf_unfiltered (_("[%s exited]\n"),
1011 target_pid_to_str (lp
->ptid
).c_str ());
1016 delete_lwp (lp
->ptid
);
1019 /* Wait for the LWP specified by LP, which we have just attached to.
1020 Returns a wait status for that LWP, to cache. */
1023 linux_nat_post_attach_wait (ptid_t ptid
, int *signalled
)
1025 pid_t new_pid
, pid
= ptid
.lwp ();
1028 if (linux_proc_pid_is_stopped (pid
))
1030 if (debug_linux_nat
)
1031 fprintf_unfiltered (gdb_stdlog
,
1032 "LNPAW: Attaching to a stopped process\n");
1034 /* The process is definitely stopped. It is in a job control
1035 stop, unless the kernel predates the TASK_STOPPED /
1036 TASK_TRACED distinction, in which case it might be in a
1037 ptrace stop. Make sure it is in a ptrace stop; from there we
1038 can kill it, signal it, et cetera.
1040 First make sure there is a pending SIGSTOP. Since we are
1041 already attached, the process can not transition from stopped
1042 to running without a PTRACE_CONT; so we know this signal will
1043 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1044 probably already in the queue (unless this kernel is old
1045 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1046 is not an RT signal, it can only be queued once. */
1047 kill_lwp (pid
, SIGSTOP
);
1049 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1050 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1051 ptrace (PTRACE_CONT
, pid
, 0, 0);
1054 /* Make sure the initial process is stopped. The user-level threads
1055 layer might want to poke around in the inferior, and that won't
1056 work if things haven't stabilized yet. */
1057 new_pid
= my_waitpid (pid
, &status
, __WALL
);
1058 gdb_assert (pid
== new_pid
);
1060 if (!WIFSTOPPED (status
))
1062 /* The pid we tried to attach has apparently just exited. */
1063 if (debug_linux_nat
)
1064 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1065 pid
, status_to_str (status
));
1069 if (WSTOPSIG (status
) != SIGSTOP
)
1072 if (debug_linux_nat
)
1073 fprintf_unfiltered (gdb_stdlog
,
1074 "LNPAW: Received %s after attaching\n",
1075 status_to_str (status
));
1082 linux_nat_target::create_inferior (const char *exec_file
,
1083 const std::string
&allargs
,
1084 char **env
, int from_tty
)
1086 maybe_disable_address_space_randomization restore_personality
1087 (disable_randomization
);
1089 /* The fork_child mechanism is synchronous and calls target_wait, so
1090 we have to mask the async mode. */
1092 /* Make sure we report all signals during startup. */
1095 inf_ptrace_target::create_inferior (exec_file
, allargs
, env
, from_tty
);
1098 /* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
1099 already attached. Returns true if a new LWP is found, false
1103 attach_proc_task_lwp_callback (ptid_t ptid
)
1105 struct lwp_info
*lp
;
1107 /* Ignore LWPs we're already attached to. */
1108 lp
= find_lwp_pid (ptid
);
1111 int lwpid
= ptid
.lwp ();
1113 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1117 /* Be quiet if we simply raced with the thread exiting.
1118 EPERM is returned if the thread's task still exists, and
1119 is marked as exited or zombie, as well as other
1120 conditions, so in that case, confirm the status in
1121 /proc/PID/status. */
1123 || (err
== EPERM
&& linux_proc_pid_is_gone (lwpid
)))
1125 if (debug_linux_nat
)
1127 fprintf_unfiltered (gdb_stdlog
,
1128 "Cannot attach to lwp %d: "
1129 "thread is gone (%d: %s)\n",
1130 lwpid
, err
, safe_strerror (err
));
1136 = linux_ptrace_attach_fail_reason_string (ptid
, err
);
1138 warning (_("Cannot attach to lwp %d: %s"),
1139 lwpid
, reason
.c_str ());
1144 if (debug_linux_nat
)
1145 fprintf_unfiltered (gdb_stdlog
,
1146 "PTRACE_ATTACH %s, 0, 0 (OK)\n",
1147 target_pid_to_str (ptid
).c_str ());
1149 lp
= add_lwp (ptid
);
1151 /* The next time we wait for this LWP we'll see a SIGSTOP as
1152 PTRACE_ATTACH brings it to a halt. */
1155 /* We need to wait for a stop before being able to make the
1156 next ptrace call on this LWP. */
1157 lp
->must_set_ptrace_flags
= 1;
1159 /* So that wait collects the SIGSTOP. */
1162 /* Also add the LWP to gdb's thread list, in case a
1163 matching libthread_db is not found (or the process uses
1165 add_thread (lp
->ptid
);
1166 set_running (lp
->ptid
, 1);
1167 set_executing (lp
->ptid
, 1);
1176 linux_nat_target::attach (const char *args
, int from_tty
)
1178 struct lwp_info
*lp
;
1182 /* Make sure we report all signals during attach. */
1187 inf_ptrace_target::attach (args
, from_tty
);
1189 catch (const gdb_exception_error
&ex
)
1191 pid_t pid
= parse_pid_to_attach (args
);
1192 std::string reason
= linux_ptrace_attach_fail_reason (pid
);
1194 if (!reason
.empty ())
1195 throw_error (ex
.error
, "warning: %s\n%s", reason
.c_str (),
1198 throw_error (ex
.error
, "%s", ex
.what ());
1201 /* The ptrace base target adds the main thread with (pid,0,0)
1202 format. Decorate it with lwp info. */
1203 ptid
= ptid_t (inferior_ptid
.pid (),
1204 inferior_ptid
.pid (),
1206 thread_change_ptid (inferior_ptid
, ptid
);
1208 /* Add the initial process as the first LWP to the list. */
1209 lp
= add_initial_lwp (ptid
);
1211 status
= linux_nat_post_attach_wait (lp
->ptid
, &lp
->signalled
);
1212 if (!WIFSTOPPED (status
))
1214 if (WIFEXITED (status
))
1216 int exit_code
= WEXITSTATUS (status
);
1218 target_terminal::ours ();
1219 target_mourn_inferior (inferior_ptid
);
1221 error (_("Unable to attach: program exited normally."));
1223 error (_("Unable to attach: program exited with code %d."),
1226 else if (WIFSIGNALED (status
))
1228 enum gdb_signal signo
;
1230 target_terminal::ours ();
1231 target_mourn_inferior (inferior_ptid
);
1233 signo
= gdb_signal_from_host (WTERMSIG (status
));
1234 error (_("Unable to attach: program terminated with signal "
1236 gdb_signal_to_name (signo
),
1237 gdb_signal_to_string (signo
));
1240 internal_error (__FILE__
, __LINE__
,
1241 _("unexpected status %d for PID %ld"),
1242 status
, (long) ptid
.lwp ());
1247 /* Save the wait status to report later. */
1249 if (debug_linux_nat
)
1250 fprintf_unfiltered (gdb_stdlog
,
1251 "LNA: waitpid %ld, saving status %s\n",
1252 (long) lp
->ptid
.pid (), status_to_str (status
));
1254 lp
->status
= status
;
1256 /* We must attach to every LWP. If /proc is mounted, use that to
1257 find them now. The inferior may be using raw clone instead of
1258 using pthreads. But even if it is using pthreads, thread_db
1259 walks structures in the inferior's address space to find the list
1260 of threads/LWPs, and those structures may well be corrupted.
1261 Note that once thread_db is loaded, we'll still use it to list
1262 threads and associate pthread info with each LWP. */
1263 linux_proc_attach_tgid_threads (lp
->ptid
.pid (),
1264 attach_proc_task_lwp_callback
);
1266 if (target_can_async_p ())
1270 /* Get pending signal of THREAD as a host signal number, for detaching
1271 purposes. This is the signal the thread last stopped for, which we
1272 need to deliver to the thread when detaching, otherwise, it'd be
1276 get_detach_signal (struct lwp_info
*lp
)
1278 enum gdb_signal signo
= GDB_SIGNAL_0
;
1280 /* If we paused threads momentarily, we may have stored pending
1281 events in lp->status or lp->waitstatus (see stop_wait_callback),
1282 and GDB core hasn't seen any signal for those threads.
1283 Otherwise, the last signal reported to the core is found in the
1284 thread object's stop_signal.
1286 There's a corner case that isn't handled here at present. Only
1287 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1288 stop_signal make sense as a real signal to pass to the inferior.
1289 Some catchpoint related events, like
1290 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1291 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1292 those traps are debug API (ptrace in our case) related and
1293 induced; the inferior wouldn't see them if it wasn't being
1294 traced. Hence, we should never pass them to the inferior, even
1295 when set to pass state. Since this corner case isn't handled by
1296 infrun.c when proceeding with a signal, for consistency, neither
1297 do we handle it here (or elsewhere in the file we check for
1298 signal pass state). Normally SIGTRAP isn't set to pass state, so
1299 this is really a corner case. */
1301 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1302 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1303 else if (lp
->status
)
1304 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1307 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1309 if (target_is_non_stop_p () && !tp
->executing
)
1311 if (tp
->suspend
.waitstatus_pending_p
)
1312 signo
= tp
->suspend
.waitstatus
.value
.sig
;
1314 signo
= tp
->suspend
.stop_signal
;
1316 else if (!target_is_non_stop_p ())
1320 get_last_target_status (&last_ptid
, nullptr);
1322 if (lp
->ptid
.lwp () == last_ptid
.lwp ())
1323 signo
= tp
->suspend
.stop_signal
;
1327 if (signo
== GDB_SIGNAL_0
)
1329 if (debug_linux_nat
)
1330 fprintf_unfiltered (gdb_stdlog
,
1331 "GPT: lwp %s has no pending signal\n",
1332 target_pid_to_str (lp
->ptid
).c_str ());
1334 else if (!signal_pass_state (signo
))
1336 if (debug_linux_nat
)
1337 fprintf_unfiltered (gdb_stdlog
,
1338 "GPT: lwp %s had signal %s, "
1339 "but it is in no pass state\n",
1340 target_pid_to_str (lp
->ptid
).c_str (),
1341 gdb_signal_to_string (signo
));
1345 if (debug_linux_nat
)
1346 fprintf_unfiltered (gdb_stdlog
,
1347 "GPT: lwp %s has pending signal %s\n",
1348 target_pid_to_str (lp
->ptid
).c_str (),
1349 gdb_signal_to_string (signo
));
1351 return gdb_signal_to_host (signo
);
1357 /* Detach from LP. If SIGNO_P is non-NULL, then it points to the
1358 signal number that should be passed to the LWP when detaching.
1359 Otherwise pass any pending signal the LWP may have, if any. */
1362 detach_one_lwp (struct lwp_info
*lp
, int *signo_p
)
1364 int lwpid
= lp
->ptid
.lwp ();
1367 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1369 if (debug_linux_nat
&& lp
->status
)
1370 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1371 strsignal (WSTOPSIG (lp
->status
)),
1372 target_pid_to_str (lp
->ptid
).c_str ());
1374 /* If there is a pending SIGSTOP, get rid of it. */
1377 if (debug_linux_nat
)
1378 fprintf_unfiltered (gdb_stdlog
,
1379 "DC: Sending SIGCONT to %s\n",
1380 target_pid_to_str (lp
->ptid
).c_str ());
1382 kill_lwp (lwpid
, SIGCONT
);
1386 if (signo_p
== NULL
)
1388 /* Pass on any pending signal for this LWP. */
1389 signo
= get_detach_signal (lp
);
1394 /* Preparing to resume may try to write registers, and fail if the
1395 lwp is zombie. If that happens, ignore the error. We'll handle
1396 it below, when detach fails with ESRCH. */
1399 linux_target
->low_prepare_to_resume (lp
);
1401 catch (const gdb_exception_error
&ex
)
1403 if (!check_ptrace_stopped_lwp_gone (lp
))
1407 if (ptrace (PTRACE_DETACH
, lwpid
, 0, signo
) < 0)
1409 int save_errno
= errno
;
1411 /* We know the thread exists, so ESRCH must mean the lwp is
1412 zombie. This can happen if one of the already-detached
1413 threads exits the whole thread group. In that case we're
1414 still attached, and must reap the lwp. */
1415 if (save_errno
== ESRCH
)
1419 ret
= my_waitpid (lwpid
, &status
, __WALL
);
1422 warning (_("Couldn't reap LWP %d while detaching: %s"),
1423 lwpid
, safe_strerror (errno
));
1425 else if (!WIFEXITED (status
) && !WIFSIGNALED (status
))
1427 warning (_("Reaping LWP %d while detaching "
1428 "returned unexpected status 0x%x"),
1434 error (_("Can't detach %s: %s"),
1435 target_pid_to_str (lp
->ptid
).c_str (),
1436 safe_strerror (save_errno
));
1439 else if (debug_linux_nat
)
1441 fprintf_unfiltered (gdb_stdlog
,
1442 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1443 target_pid_to_str (lp
->ptid
).c_str (),
1447 delete_lwp (lp
->ptid
);
1451 detach_callback (struct lwp_info
*lp
)
1453 /* We don't actually detach from the thread group leader just yet.
1454 If the thread group exits, we must reap the zombie clone lwps
1455 before we're able to reap the leader. */
1456 if (lp
->ptid
.lwp () != lp
->ptid
.pid ())
1457 detach_one_lwp (lp
, NULL
);
1462 linux_nat_target::detach (inferior
*inf
, int from_tty
)
1464 struct lwp_info
*main_lwp
;
1467 /* Don't unregister from the event loop, as there may be other
1468 inferiors running. */
1470 /* Stop all threads before detaching. ptrace requires that the
1471 thread is stopped to successfully detach. */
1472 iterate_over_lwps (ptid_t (pid
), stop_callback
);
1473 /* ... and wait until all of them have reported back that
1474 they're no longer running. */
1475 iterate_over_lwps (ptid_t (pid
), stop_wait_callback
);
1477 iterate_over_lwps (ptid_t (pid
), detach_callback
);
1479 /* Only the initial process should be left right now. */
1480 gdb_assert (num_lwps (pid
) == 1);
1482 main_lwp
= find_lwp_pid (ptid_t (pid
));
1484 if (forks_exist_p ())
1486 /* Multi-fork case. The current inferior_ptid is being detached
1487 from, but there are other viable forks to debug. Detach from
1488 the current fork, and context-switch to the first
1490 linux_fork_detach (from_tty
);
1494 target_announce_detach (from_tty
);
1496 /* Pass on any pending signal for the last LWP. */
1497 int signo
= get_detach_signal (main_lwp
);
1499 detach_one_lwp (main_lwp
, &signo
);
1501 detach_success (inf
);
1505 /* Resume execution of the inferior process. If STEP is nonzero,
1506 single-step it. If SIGNAL is nonzero, give it that signal. */
1509 linux_resume_one_lwp_throw (struct lwp_info
*lp
, int step
,
1510 enum gdb_signal signo
)
1514 /* stop_pc doubles as the PC the LWP had when it was last resumed.
1515 We only presently need that if the LWP is stepped though (to
1516 handle the case of stepping a breakpoint instruction). */
1519 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
1521 lp
->stop_pc
= regcache_read_pc (regcache
);
1526 linux_target
->low_prepare_to_resume (lp
);
1527 linux_target
->low_resume (lp
->ptid
, step
, signo
);
1529 /* Successfully resumed. Clear state that no longer makes sense,
1530 and mark the LWP as running. Must not do this before resuming
1531 otherwise if that fails other code will be confused. E.g., we'd
1532 later try to stop the LWP and hang forever waiting for a stop
1533 status. Note that we must not throw after this is cleared,
1534 otherwise handle_zombie_lwp_error would get confused. */
1537 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1538 registers_changed_ptid (lp
->ptid
);
1541 /* Called when we try to resume a stopped LWP and that errors out. If
1542 the LWP is no longer in ptrace-stopped state (meaning it's zombie,
1543 or about to become), discard the error, clear any pending status
1544 the LWP may have, and return true (we'll collect the exit status
1545 soon enough). Otherwise, return false. */
1548 check_ptrace_stopped_lwp_gone (struct lwp_info
*lp
)
1550 /* If we get an error after resuming the LWP successfully, we'd
1551 confuse !T state for the LWP being gone. */
1552 gdb_assert (lp
->stopped
);
1554 /* We can't just check whether the LWP is in 'Z (Zombie)' state,
1555 because even if ptrace failed with ESRCH, the tracee may be "not
1556 yet fully dead", but already refusing ptrace requests. In that
1557 case the tracee has 'R (Running)' state for a little bit
1558 (observed in Linux 3.18). See also the note on ESRCH in the
1559 ptrace(2) man page. Instead, check whether the LWP has any state
1560 other than ptrace-stopped. */
1562 /* Don't assume anything if /proc/PID/status can't be read. */
1563 if (linux_proc_pid_is_trace_stopped_nowarn (lp
->ptid
.lwp ()) == 0)
1565 lp
->stop_reason
= TARGET_STOPPED_BY_NO_REASON
;
1567 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
1573 /* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
1574 disappears while we try to resume it. */
1577 linux_resume_one_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1581 linux_resume_one_lwp_throw (lp
, step
, signo
);
1583 catch (const gdb_exception_error
&ex
)
1585 if (!check_ptrace_stopped_lwp_gone (lp
))
1593 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1597 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
1599 if (inf
->vfork_child
!= NULL
)
1601 if (debug_linux_nat
)
1602 fprintf_unfiltered (gdb_stdlog
,
1603 "RC: Not resuming %s (vfork parent)\n",
1604 target_pid_to_str (lp
->ptid
).c_str ());
1606 else if (!lwp_status_pending_p (lp
))
1608 if (debug_linux_nat
)
1609 fprintf_unfiltered (gdb_stdlog
,
1610 "RC: Resuming sibling %s, %s, %s\n",
1611 target_pid_to_str (lp
->ptid
).c_str (),
1612 (signo
!= GDB_SIGNAL_0
1613 ? strsignal (gdb_signal_to_host (signo
))
1615 step
? "step" : "resume");
1617 linux_resume_one_lwp (lp
, step
, signo
);
1621 if (debug_linux_nat
)
1622 fprintf_unfiltered (gdb_stdlog
,
1623 "RC: Not resuming sibling %s (has pending)\n",
1624 target_pid_to_str (lp
->ptid
).c_str ());
1629 if (debug_linux_nat
)
1630 fprintf_unfiltered (gdb_stdlog
,
1631 "RC: Not resuming sibling %s (not stopped)\n",
1632 target_pid_to_str (lp
->ptid
).c_str ());
1636 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1637 Resume LWP with the last stop signal, if it is in pass state. */
1640 linux_nat_resume_callback (struct lwp_info
*lp
, struct lwp_info
*except
)
1642 enum gdb_signal signo
= GDB_SIGNAL_0
;
1649 struct thread_info
*thread
;
1651 thread
= find_thread_ptid (lp
->ptid
);
1654 signo
= thread
->suspend
.stop_signal
;
1655 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1659 resume_lwp (lp
, 0, signo
);
1664 resume_clear_callback (struct lwp_info
*lp
)
1667 lp
->last_resume_kind
= resume_stop
;
1672 resume_set_callback (struct lwp_info
*lp
)
1675 lp
->last_resume_kind
= resume_continue
;
1680 linux_nat_target::resume (ptid_t ptid
, int step
, enum gdb_signal signo
)
1682 struct lwp_info
*lp
;
1685 if (debug_linux_nat
)
1686 fprintf_unfiltered (gdb_stdlog
,
1687 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1688 step
? "step" : "resume",
1689 target_pid_to_str (ptid
).c_str (),
1690 (signo
!= GDB_SIGNAL_0
1691 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1692 target_pid_to_str (inferior_ptid
).c_str ());
1694 /* A specific PTID means `step only this process id'. */
1695 resume_many
= (minus_one_ptid
== ptid
1698 /* Mark the lwps we're resuming as resumed. */
1699 iterate_over_lwps (ptid
, resume_set_callback
);
1701 /* See if it's the current inferior that should be handled
1704 lp
= find_lwp_pid (inferior_ptid
);
1706 lp
= find_lwp_pid (ptid
);
1707 gdb_assert (lp
!= NULL
);
1709 /* Remember if we're stepping. */
1710 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1712 /* If we have a pending wait status for this thread, there is no
1713 point in resuming the process. But first make sure that
1714 linux_nat_wait won't preemptively handle the event - we
1715 should never take this short-circuit if we are going to
1716 leave LP running, since we have skipped resuming all the
1717 other threads. This bit of code needs to be synchronized
1718 with linux_nat_wait. */
1720 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1723 && WSTOPSIG (lp
->status
)
1724 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1726 if (debug_linux_nat
)
1727 fprintf_unfiltered (gdb_stdlog
,
1728 "LLR: Not short circuiting for ignored "
1729 "status 0x%x\n", lp
->status
);
1731 /* FIXME: What should we do if we are supposed to continue
1732 this thread with a signal? */
1733 gdb_assert (signo
== GDB_SIGNAL_0
);
1734 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1739 if (lwp_status_pending_p (lp
))
1741 /* FIXME: What should we do if we are supposed to continue
1742 this thread with a signal? */
1743 gdb_assert (signo
== GDB_SIGNAL_0
);
1745 if (debug_linux_nat
)
1746 fprintf_unfiltered (gdb_stdlog
,
1747 "LLR: Short circuiting for status 0x%x\n",
1750 if (target_can_async_p ())
1753 /* Tell the event loop we have something to process. */
1760 iterate_over_lwps (ptid
, [=] (struct lwp_info
*info
)
1762 return linux_nat_resume_callback (info
, lp
);
1765 if (debug_linux_nat
)
1766 fprintf_unfiltered (gdb_stdlog
,
1767 "LLR: %s %s, %s (resume event thread)\n",
1768 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1769 target_pid_to_str (lp
->ptid
).c_str (),
1770 (signo
!= GDB_SIGNAL_0
1771 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1773 linux_resume_one_lwp (lp
, step
, signo
);
1775 if (target_can_async_p ())
1779 /* Send a signal to an LWP. */
1782 kill_lwp (int lwpid
, int signo
)
1787 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1788 if (errno
== ENOSYS
)
1790 /* If tkill fails, then we are not using nptl threads, a
1791 configuration we no longer support. */
1792 perror_with_name (("tkill"));
1797 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1798 event, check if the core is interested in it: if not, ignore the
1799 event, and keep waiting; otherwise, we need to toggle the LWP's
1800 syscall entry/exit status, since the ptrace event itself doesn't
1801 indicate it, and report the trap to higher layers. */
1804 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1806 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1807 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1808 thread_info
*thread
= find_thread_ptid (lp
->ptid
);
1809 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, thread
);
1813 /* If we're stopping threads, there's a SIGSTOP pending, which
1814 makes it so that the LWP reports an immediate syscall return,
1815 followed by the SIGSTOP. Skip seeing that "return" using
1816 PTRACE_CONT directly, and let stop_wait_callback collect the
1817 SIGSTOP. Later when the thread is resumed, a new syscall
1818 entry event. If we didn't do this (and returned 0), we'd
1819 leave a syscall entry pending, and our caller, by using
1820 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1821 itself. Later, when the user re-resumes this LWP, we'd see
1822 another syscall entry event and we'd mistake it for a return.
1824 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1825 (leaving immediately with LWP->signalled set, without issuing
1826 a PTRACE_CONT), it would still be problematic to leave this
1827 syscall enter pending, as later when the thread is resumed,
1828 it would then see the same syscall exit mentioned above,
1829 followed by the delayed SIGSTOP, while the syscall didn't
1830 actually get to execute. It seems it would be even more
1831 confusing to the user. */
1833 if (debug_linux_nat
)
1834 fprintf_unfiltered (gdb_stdlog
,
1835 "LHST: ignoring syscall %d "
1836 "for LWP %ld (stopping threads), "
1837 "resuming with PTRACE_CONT for SIGSTOP\n",
1841 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1842 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
1847 /* Always update the entry/return state, even if this particular
1848 syscall isn't interesting to the core now. In async mode,
1849 the user could install a new catchpoint for this syscall
1850 between syscall enter/return, and we'll need to know to
1851 report a syscall return if that happens. */
1852 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1853 ? TARGET_WAITKIND_SYSCALL_RETURN
1854 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1856 if (catch_syscall_enabled ())
1858 if (catching_syscall_number (syscall_number
))
1860 /* Alright, an event to report. */
1861 ourstatus
->kind
= lp
->syscall_state
;
1862 ourstatus
->value
.syscall_number
= syscall_number
;
1864 if (debug_linux_nat
)
1865 fprintf_unfiltered (gdb_stdlog
,
1866 "LHST: stopping for %s of syscall %d"
1869 == TARGET_WAITKIND_SYSCALL_ENTRY
1870 ? "entry" : "return",
1876 if (debug_linux_nat
)
1877 fprintf_unfiltered (gdb_stdlog
,
1878 "LHST: ignoring %s of syscall %d "
1880 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1881 ? "entry" : "return",
1887 /* If we had been syscall tracing, and hence used PT_SYSCALL
1888 before on this LWP, it could happen that the user removes all
1889 syscall catchpoints before we get to process this event.
1890 There are two noteworthy issues here:
1892 - When stopped at a syscall entry event, resuming with
1893 PT_STEP still resumes executing the syscall and reports a
1896 - Only PT_SYSCALL catches syscall enters. If we last
1897 single-stepped this thread, then this event can't be a
1898 syscall enter. If we last single-stepped this thread, this
1899 has to be a syscall exit.
1901 The points above mean that the next resume, be it PT_STEP or
1902 PT_CONTINUE, can not trigger a syscall trace event. */
1903 if (debug_linux_nat
)
1904 fprintf_unfiltered (gdb_stdlog
,
1905 "LHST: caught syscall event "
1906 "with no syscall catchpoints."
1907 " %d for LWP %ld, ignoring\n",
1910 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1913 /* The core isn't interested in this event. For efficiency, avoid
1914 stopping all threads only to have the core resume them all again.
1915 Since we're not stopping threads, if we're still syscall tracing
1916 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1917 subsequent syscall. Simply resume using the inf-ptrace layer,
1918 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1920 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
1924 /* Handle a GNU/Linux extended wait response. If we see a clone
1925 event, we need to add the new LWP to our list (and not report the
1926 trap to higher layers). This function returns non-zero if the
1927 event should be ignored and we should wait again. If STOPPING is
1928 true, the new LWP remains stopped, otherwise it is continued. */
1931 linux_handle_extended_wait (struct lwp_info
*lp
, int status
)
1933 int pid
= lp
->ptid
.lwp ();
1934 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1935 int event
= linux_ptrace_get_extended_event (status
);
1937 /* All extended events we currently use are mid-syscall. Only
1938 PTRACE_EVENT_STOP is delivered more like a signal-stop, but
1939 you have to be using PTRACE_SEIZE to get that. */
1940 lp
->syscall_state
= TARGET_WAITKIND_SYSCALL_ENTRY
;
1942 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1943 || event
== PTRACE_EVENT_CLONE
)
1945 unsigned long new_pid
;
1948 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1950 /* If we haven't already seen the new PID stop, wait for it now. */
1951 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1953 /* The new child has a pending SIGSTOP. We can't affect it until it
1954 hits the SIGSTOP, but we're already attached. */
1955 ret
= my_waitpid (new_pid
, &status
, __WALL
);
1957 perror_with_name (_("waiting for new child"));
1958 else if (ret
!= new_pid
)
1959 internal_error (__FILE__
, __LINE__
,
1960 _("wait returned unexpected PID %d"), ret
);
1961 else if (!WIFSTOPPED (status
))
1962 internal_error (__FILE__
, __LINE__
,
1963 _("wait returned unexpected status 0x%x"), status
);
1966 ourstatus
->value
.related_pid
= ptid_t (new_pid
, new_pid
, 0);
1968 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
1970 /* The arch-specific native code may need to know about new
1971 forks even if those end up never mapped to an
1973 linux_target
->low_new_fork (lp
, new_pid
);
1976 if (event
== PTRACE_EVENT_FORK
1977 && linux_fork_checkpointing_p (lp
->ptid
.pid ()))
1979 /* Handle checkpointing by linux-fork.c here as a special
1980 case. We don't want the follow-fork-mode or 'catch fork'
1981 to interfere with this. */
1983 /* This won't actually modify the breakpoint list, but will
1984 physically remove the breakpoints from the child. */
1985 detach_breakpoints (ptid_t (new_pid
, new_pid
, 0));
1987 /* Retain child fork in ptrace (stopped) state. */
1988 if (!find_fork_pid (new_pid
))
1991 /* Report as spurious, so that infrun doesn't want to follow
1992 this fork. We're actually doing an infcall in
1994 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
1996 /* Report the stop to the core. */
2000 if (event
== PTRACE_EVENT_FORK
)
2001 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
2002 else if (event
== PTRACE_EVENT_VFORK
)
2003 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
2004 else if (event
== PTRACE_EVENT_CLONE
)
2006 struct lwp_info
*new_lp
;
2008 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2010 if (debug_linux_nat
)
2011 fprintf_unfiltered (gdb_stdlog
,
2012 "LHEW: Got clone event "
2013 "from LWP %d, new child is LWP %ld\n",
2016 new_lp
= add_lwp (ptid_t (lp
->ptid
.pid (), new_pid
, 0));
2017 new_lp
->stopped
= 1;
2018 new_lp
->resumed
= 1;
2020 /* If the thread_db layer is active, let it record the user
2021 level thread id and status, and add the thread to GDB's
2023 if (!thread_db_notice_clone (lp
->ptid
, new_lp
->ptid
))
2025 /* The process is not using thread_db. Add the LWP to
2027 target_post_attach (new_lp
->ptid
.lwp ());
2028 add_thread (new_lp
->ptid
);
2031 /* Even if we're stopping the thread for some reason
2032 internal to this module, from the perspective of infrun
2033 and the user/frontend, this new thread is running until
2034 it next reports a stop. */
2035 set_running (new_lp
->ptid
, 1);
2036 set_executing (new_lp
->ptid
, 1);
2038 if (WSTOPSIG (status
) != SIGSTOP
)
2040 /* This can happen if someone starts sending signals to
2041 the new thread before it gets a chance to run, which
2042 have a lower number than SIGSTOP (e.g. SIGUSR1).
2043 This is an unlikely case, and harder to handle for
2044 fork / vfork than for clone, so we do not try - but
2045 we handle it for clone events here. */
2047 new_lp
->signalled
= 1;
2049 /* We created NEW_LP so it cannot yet contain STATUS. */
2050 gdb_assert (new_lp
->status
== 0);
2052 /* Save the wait status to report later. */
2053 if (debug_linux_nat
)
2054 fprintf_unfiltered (gdb_stdlog
,
2055 "LHEW: waitpid of new LWP %ld, "
2056 "saving status %s\n",
2057 (long) new_lp
->ptid
.lwp (),
2058 status_to_str (status
));
2059 new_lp
->status
= status
;
2061 else if (report_thread_events
)
2063 new_lp
->waitstatus
.kind
= TARGET_WAITKIND_THREAD_CREATED
;
2064 new_lp
->status
= status
;
2073 if (event
== PTRACE_EVENT_EXEC
)
2075 if (debug_linux_nat
)
2076 fprintf_unfiltered (gdb_stdlog
,
2077 "LHEW: Got exec event from LWP %ld\n",
2080 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2081 ourstatus
->value
.execd_pathname
2082 = xstrdup (linux_proc_pid_to_exec_file (pid
));
2084 /* The thread that execed must have been resumed, but, when a
2085 thread execs, it changes its tid to the tgid, and the old
2086 tgid thread might have not been resumed. */
2091 if (event
== PTRACE_EVENT_VFORK_DONE
)
2093 if (current_inferior ()->waiting_for_vfork_done
)
2095 if (debug_linux_nat
)
2096 fprintf_unfiltered (gdb_stdlog
,
2097 "LHEW: Got expected PTRACE_EVENT_"
2098 "VFORK_DONE from LWP %ld: stopping\n",
2101 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2105 if (debug_linux_nat
)
2106 fprintf_unfiltered (gdb_stdlog
,
2107 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2108 "from LWP %ld: ignoring\n",
2113 internal_error (__FILE__
, __LINE__
,
2114 _("unknown ptrace event %d"), event
);
2117 /* Suspend waiting for a signal. We're mostly interested in
2123 if (debug_linux_nat
)
2124 fprintf_unfiltered (gdb_stdlog
, "linux-nat: about to sigsuspend\n");
2125 sigsuspend (&suspend_mask
);
2127 /* If the quit flag is set, it means that the user pressed Ctrl-C
2128 and we're debugging a process that is running on a separate
2129 terminal, so we must forward the Ctrl-C to the inferior. (If the
2130 inferior is sharing GDB's terminal, then the Ctrl-C reaches the
2131 inferior directly.) We must do this here because functions that
2132 need to block waiting for a signal loop forever until there's an
2133 event to report before returning back to the event loop. */
2134 if (!target_terminal::is_ours ())
2136 if (check_quit_flag ())
2137 target_pass_ctrlc ();
2141 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2145 wait_lwp (struct lwp_info
*lp
)
2149 int thread_dead
= 0;
2152 gdb_assert (!lp
->stopped
);
2153 gdb_assert (lp
->status
== 0);
2155 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2156 block_child_signals (&prev_mask
);
2160 pid
= my_waitpid (lp
->ptid
.lwp (), &status
, __WALL
| WNOHANG
);
2161 if (pid
== -1 && errno
== ECHILD
)
2163 /* The thread has previously exited. We need to delete it
2164 now because if this was a non-leader thread execing, we
2165 won't get an exit event. See comments on exec events at
2166 the top of the file. */
2168 if (debug_linux_nat
)
2169 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2170 target_pid_to_str (lp
->ptid
).c_str ());
2175 /* Bugs 10970, 12702.
2176 Thread group leader may have exited in which case we'll lock up in
2177 waitpid if there are other threads, even if they are all zombies too.
2178 Basically, we're not supposed to use waitpid this way.
2179 tkill(pid,0) cannot be used here as it gets ESRCH for both
2180 for zombie and running processes.
2182 As a workaround, check if we're waiting for the thread group leader and
2183 if it's a zombie, and avoid calling waitpid if it is.
2185 This is racy, what if the tgl becomes a zombie right after we check?
2186 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2187 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2189 if (lp
->ptid
.pid () == lp
->ptid
.lwp ()
2190 && linux_proc_pid_is_zombie (lp
->ptid
.lwp ()))
2193 if (debug_linux_nat
)
2194 fprintf_unfiltered (gdb_stdlog
,
2195 "WL: Thread group leader %s vanished.\n",
2196 target_pid_to_str (lp
->ptid
).c_str ());
2200 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2201 get invoked despite our caller had them intentionally blocked by
2202 block_child_signals. This is sensitive only to the loop of
2203 linux_nat_wait_1 and there if we get called my_waitpid gets called
2204 again before it gets to sigsuspend so we can safely let the handlers
2205 get executed here. */
2209 restore_child_signals_mask (&prev_mask
);
2213 gdb_assert (pid
== lp
->ptid
.lwp ());
2215 if (debug_linux_nat
)
2217 fprintf_unfiltered (gdb_stdlog
,
2218 "WL: waitpid %s received %s\n",
2219 target_pid_to_str (lp
->ptid
).c_str (),
2220 status_to_str (status
));
2223 /* Check if the thread has exited. */
2224 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2226 if (report_thread_events
2227 || lp
->ptid
.pid () == lp
->ptid
.lwp ())
2229 if (debug_linux_nat
)
2230 fprintf_unfiltered (gdb_stdlog
, "WL: LWP %d exited.\n",
2233 /* If this is the leader exiting, it means the whole
2234 process is gone. Store the status to report to the
2235 core. Store it in lp->waitstatus, because lp->status
2236 would be ambiguous (W_EXITCODE(0,0) == 0). */
2237 store_waitstatus (&lp
->waitstatus
, status
);
2242 if (debug_linux_nat
)
2243 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2244 target_pid_to_str (lp
->ptid
).c_str ());
2254 gdb_assert (WIFSTOPPED (status
));
2257 if (lp
->must_set_ptrace_flags
)
2259 struct inferior
*inf
= find_inferior_pid (lp
->ptid
.pid ());
2260 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2262 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2263 lp
->must_set_ptrace_flags
= 0;
2266 /* Handle GNU/Linux's syscall SIGTRAPs. */
2267 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2269 /* No longer need the sysgood bit. The ptrace event ends up
2270 recorded in lp->waitstatus if we care for it. We can carry
2271 on handling the event like a regular SIGTRAP from here
2273 status
= W_STOPCODE (SIGTRAP
);
2274 if (linux_handle_syscall_trap (lp
, 1))
2275 return wait_lwp (lp
);
2279 /* Almost all other ptrace-stops are known to be outside of system
2280 calls, with further exceptions in linux_handle_extended_wait. */
2281 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
2284 /* Handle GNU/Linux's extended waitstatus for trace events. */
2285 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
2286 && linux_is_extended_waitstatus (status
))
2288 if (debug_linux_nat
)
2289 fprintf_unfiltered (gdb_stdlog
,
2290 "WL: Handling extended status 0x%06x\n",
2292 linux_handle_extended_wait (lp
, status
);
2299 /* Send a SIGSTOP to LP. */
2302 stop_callback (struct lwp_info
*lp
)
2304 if (!lp
->stopped
&& !lp
->signalled
)
2308 if (debug_linux_nat
)
2310 fprintf_unfiltered (gdb_stdlog
,
2311 "SC: kill %s **<SIGSTOP>**\n",
2312 target_pid_to_str (lp
->ptid
).c_str ());
2315 ret
= kill_lwp (lp
->ptid
.lwp (), SIGSTOP
);
2316 if (debug_linux_nat
)
2318 fprintf_unfiltered (gdb_stdlog
,
2319 "SC: lwp kill %d %s\n",
2321 errno
? safe_strerror (errno
) : "ERRNO-OK");
2325 gdb_assert (lp
->status
== 0);
2331 /* Request a stop on LWP. */
2334 linux_stop_lwp (struct lwp_info
*lwp
)
2336 stop_callback (lwp
);
2339 /* See linux-nat.h */
2342 linux_stop_and_wait_all_lwps (void)
2344 /* Stop all LWP's ... */
2345 iterate_over_lwps (minus_one_ptid
, stop_callback
);
2347 /* ... and wait until all of them have reported back that
2348 they're no longer running. */
2349 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
);
2352 /* See linux-nat.h */
2355 linux_unstop_all_lwps (void)
2357 iterate_over_lwps (minus_one_ptid
,
2358 [] (struct lwp_info
*info
)
2360 return resume_stopped_resumed_lwps (info
, minus_one_ptid
);
2364 /* Return non-zero if LWP PID has a pending SIGINT. */
2367 linux_nat_has_pending_sigint (int pid
)
2369 sigset_t pending
, blocked
, ignored
;
2371 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2373 if (sigismember (&pending
, SIGINT
)
2374 && !sigismember (&ignored
, SIGINT
))
2380 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2383 set_ignore_sigint (struct lwp_info
*lp
)
2385 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2386 flag to consume the next one. */
2387 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2388 && WSTOPSIG (lp
->status
) == SIGINT
)
2391 lp
->ignore_sigint
= 1;
2396 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2397 This function is called after we know the LWP has stopped; if the LWP
2398 stopped before the expected SIGINT was delivered, then it will never have
2399 arrived. Also, if the signal was delivered to a shared queue and consumed
2400 by a different thread, it will never be delivered to this LWP. */
2403 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2405 if (!lp
->ignore_sigint
)
2408 if (!linux_nat_has_pending_sigint (lp
->ptid
.lwp ()))
2410 if (debug_linux_nat
)
2411 fprintf_unfiltered (gdb_stdlog
,
2412 "MCIS: Clearing bogus flag for %s\n",
2413 target_pid_to_str (lp
->ptid
).c_str ());
2414 lp
->ignore_sigint
= 0;
2418 /* Fetch the possible triggered data watchpoint info and store it in
2421 On some archs, like x86, that use debug registers to set
2422 watchpoints, it's possible that the way to know which watched
2423 address trapped, is to check the register that is used to select
2424 which address to watch. Problem is, between setting the watchpoint
2425 and reading back which data address trapped, the user may change
2426 the set of watchpoints, and, as a consequence, GDB changes the
2427 debug registers in the inferior. To avoid reading back a stale
2428 stopped-data-address when that happens, we cache in LP the fact
2429 that a watchpoint trapped, and the corresponding data address, as
2430 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2431 registers meanwhile, we have the cached data we can rely on. */
2434 check_stopped_by_watchpoint (struct lwp_info
*lp
)
2436 scoped_restore save_inferior_ptid
= make_scoped_restore (&inferior_ptid
);
2437 inferior_ptid
= lp
->ptid
;
2439 if (linux_target
->low_stopped_by_watchpoint ())
2441 lp
->stop_reason
= TARGET_STOPPED_BY_WATCHPOINT
;
2442 lp
->stopped_data_address_p
2443 = linux_target
->low_stopped_data_address (&lp
->stopped_data_address
);
2446 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2449 /* Returns true if the LWP had stopped for a watchpoint. */
2452 linux_nat_target::stopped_by_watchpoint ()
2454 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2456 gdb_assert (lp
!= NULL
);
2458 return lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
;
2462 linux_nat_target::stopped_data_address (CORE_ADDR
*addr_p
)
2464 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2466 gdb_assert (lp
!= NULL
);
2468 *addr_p
= lp
->stopped_data_address
;
2470 return lp
->stopped_data_address_p
;
2473 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2476 linux_nat_target::low_status_is_event (int status
)
2478 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2481 /* Wait until LP is stopped. */
2484 stop_wait_callback (struct lwp_info
*lp
)
2486 struct inferior
*inf
= find_inferior_ptid (lp
->ptid
);
2488 /* If this is a vfork parent, bail out, it is not going to report
2489 any SIGSTOP until the vfork is done with. */
2490 if (inf
->vfork_child
!= NULL
)
2497 status
= wait_lwp (lp
);
2501 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2502 && WSTOPSIG (status
) == SIGINT
)
2504 lp
->ignore_sigint
= 0;
2507 ptrace (PTRACE_CONT
, lp
->ptid
.lwp (), 0, 0);
2509 if (debug_linux_nat
)
2510 fprintf_unfiltered (gdb_stdlog
,
2511 "PTRACE_CONT %s, 0, 0 (%s) "
2512 "(discarding SIGINT)\n",
2513 target_pid_to_str (lp
->ptid
).c_str (),
2514 errno
? safe_strerror (errno
) : "OK");
2516 return stop_wait_callback (lp
);
2519 maybe_clear_ignore_sigint (lp
);
2521 if (WSTOPSIG (status
) != SIGSTOP
)
2523 /* The thread was stopped with a signal other than SIGSTOP. */
2525 if (debug_linux_nat
)
2526 fprintf_unfiltered (gdb_stdlog
,
2527 "SWC: Pending event %s in %s\n",
2528 status_to_str ((int) status
),
2529 target_pid_to_str (lp
->ptid
).c_str ());
2531 /* Save the sigtrap event. */
2532 lp
->status
= status
;
2533 gdb_assert (lp
->signalled
);
2534 save_stop_reason (lp
);
2538 /* We caught the SIGSTOP that we intended to catch. */
2540 if (debug_linux_nat
)
2541 fprintf_unfiltered (gdb_stdlog
,
2542 "SWC: Expected SIGSTOP caught for %s.\n",
2543 target_pid_to_str (lp
->ptid
).c_str ());
2547 /* If we are waiting for this stop so we can report the thread
2548 stopped then we need to record this status. Otherwise, we can
2549 now discard this stop event. */
2550 if (lp
->last_resume_kind
== resume_stop
)
2552 lp
->status
= status
;
2553 save_stop_reason (lp
);
2561 /* Return non-zero if LP has a wait status pending. Discard the
2562 pending event and resume the LWP if the event that originally
2563 caused the stop became uninteresting. */
2566 status_callback (struct lwp_info
*lp
)
2568 /* Only report a pending wait status if we pretend that this has
2569 indeed been resumed. */
2573 if (!lwp_status_pending_p (lp
))
2576 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
2577 || lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2579 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2583 pc
= regcache_read_pc (regcache
);
2585 if (pc
!= lp
->stop_pc
)
2587 if (debug_linux_nat
)
2588 fprintf_unfiltered (gdb_stdlog
,
2589 "SC: PC of %s changed. was=%s, now=%s\n",
2590 target_pid_to_str (lp
->ptid
).c_str (),
2591 paddress (target_gdbarch (), lp
->stop_pc
),
2592 paddress (target_gdbarch (), pc
));
2596 #if !USE_SIGTRAP_SIGINFO
2597 else if (!breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2599 if (debug_linux_nat
)
2600 fprintf_unfiltered (gdb_stdlog
,
2601 "SC: previous breakpoint of %s, at %s gone\n",
2602 target_pid_to_str (lp
->ptid
).c_str (),
2603 paddress (target_gdbarch (), lp
->stop_pc
));
2611 if (debug_linux_nat
)
2612 fprintf_unfiltered (gdb_stdlog
,
2613 "SC: pending event of %s cancelled.\n",
2614 target_pid_to_str (lp
->ptid
).c_str ());
2617 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2625 /* Count the LWP's that have had events. */
2628 count_events_callback (struct lwp_info
*lp
, int *count
)
2630 gdb_assert (count
!= NULL
);
2632 /* Select only resumed LWPs that have an event pending. */
2633 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2639 /* Select the LWP (if any) that is currently being single-stepped. */
2642 select_singlestep_lwp_callback (struct lwp_info
*lp
)
2644 if (lp
->last_resume_kind
== resume_step
2651 /* Returns true if LP has a status pending. */
2654 lwp_status_pending_p (struct lwp_info
*lp
)
2656 /* We check for lp->waitstatus in addition to lp->status, because we
2657 can have pending process exits recorded in lp->status and
2658 W_EXITCODE(0,0) happens to be 0. */
2659 return lp
->status
!= 0 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
;
2662 /* Select the Nth LWP that has had an event. */
2665 select_event_lwp_callback (struct lwp_info
*lp
, int *selector
)
2667 gdb_assert (selector
!= NULL
);
2669 /* Select only resumed LWPs that have an event pending. */
2670 if (lp
->resumed
&& lwp_status_pending_p (lp
))
2671 if ((*selector
)-- == 0)
2677 /* Called when the LWP stopped for a signal/trap. If it stopped for a
2678 trap check what caused it (breakpoint, watchpoint, trace, etc.),
2679 and save the result in the LWP's stop_reason field. If it stopped
2680 for a breakpoint, decrement the PC if necessary on the lwp's
2684 save_stop_reason (struct lwp_info
*lp
)
2686 struct regcache
*regcache
;
2687 struct gdbarch
*gdbarch
;
2690 #if USE_SIGTRAP_SIGINFO
2694 gdb_assert (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
);
2695 gdb_assert (lp
->status
!= 0);
2697 if (!linux_target
->low_status_is_event (lp
->status
))
2700 regcache
= get_thread_regcache (lp
->ptid
);
2701 gdbarch
= regcache
->arch ();
2703 pc
= regcache_read_pc (regcache
);
2704 sw_bp_pc
= pc
- gdbarch_decr_pc_after_break (gdbarch
);
2706 #if USE_SIGTRAP_SIGINFO
2707 if (linux_nat_get_siginfo (lp
->ptid
, &siginfo
))
2709 if (siginfo
.si_signo
== SIGTRAP
)
2711 if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
)
2712 && GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2714 /* The si_code is ambiguous on this arch -- check debug
2716 if (!check_stopped_by_watchpoint (lp
))
2717 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2719 else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo
.si_code
))
2721 /* If we determine the LWP stopped for a SW breakpoint,
2722 trust it. Particularly don't check watchpoint
2723 registers, because at least on s390, we'd find
2724 stopped-by-watchpoint as long as there's a watchpoint
2726 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2728 else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo
.si_code
))
2730 /* This can indicate either a hardware breakpoint or
2731 hardware watchpoint. Check debug registers. */
2732 if (!check_stopped_by_watchpoint (lp
))
2733 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2735 else if (siginfo
.si_code
== TRAP_TRACE
)
2737 if (debug_linux_nat
)
2738 fprintf_unfiltered (gdb_stdlog
,
2739 "CSBB: %s stopped by trace\n",
2740 target_pid_to_str (lp
->ptid
).c_str ());
2742 /* We may have single stepped an instruction that
2743 triggered a watchpoint. In that case, on some
2744 architectures (such as x86), instead of TRAP_HWBKPT,
2745 si_code indicates TRAP_TRACE, and we need to check
2746 the debug registers separately. */
2747 check_stopped_by_watchpoint (lp
);
2752 if ((!lp
->step
|| lp
->stop_pc
== sw_bp_pc
)
2753 && software_breakpoint_inserted_here_p (regcache
->aspace (),
2756 /* The LWP was either continued, or stepped a software
2757 breakpoint instruction. */
2758 lp
->stop_reason
= TARGET_STOPPED_BY_SW_BREAKPOINT
;
2761 if (hardware_breakpoint_inserted_here_p (regcache
->aspace (), pc
))
2762 lp
->stop_reason
= TARGET_STOPPED_BY_HW_BREAKPOINT
;
2764 if (lp
->stop_reason
== TARGET_STOPPED_BY_NO_REASON
)
2765 check_stopped_by_watchpoint (lp
);
2768 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
)
2770 if (debug_linux_nat
)
2771 fprintf_unfiltered (gdb_stdlog
,
2772 "CSBB: %s stopped by software breakpoint\n",
2773 target_pid_to_str (lp
->ptid
).c_str ());
2775 /* Back up the PC if necessary. */
2777 regcache_write_pc (regcache
, sw_bp_pc
);
2779 /* Update this so we record the correct stop PC below. */
2782 else if (lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
)
2784 if (debug_linux_nat
)
2785 fprintf_unfiltered (gdb_stdlog
,
2786 "CSBB: %s stopped by hardware breakpoint\n",
2787 target_pid_to_str (lp
->ptid
).c_str ());
2789 else if (lp
->stop_reason
== TARGET_STOPPED_BY_WATCHPOINT
)
2791 if (debug_linux_nat
)
2792 fprintf_unfiltered (gdb_stdlog
,
2793 "CSBB: %s stopped by hardware watchpoint\n",
2794 target_pid_to_str (lp
->ptid
).c_str ());
2801 /* Returns true if the LWP had stopped for a software breakpoint. */
2804 linux_nat_target::stopped_by_sw_breakpoint ()
2806 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2808 gdb_assert (lp
!= NULL
);
2810 return lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
;
2813 /* Implement the supports_stopped_by_sw_breakpoint method. */
2816 linux_nat_target::supports_stopped_by_sw_breakpoint ()
2818 return USE_SIGTRAP_SIGINFO
;
2821 /* Returns true if the LWP had stopped for a hardware
2822 breakpoint/watchpoint. */
2825 linux_nat_target::stopped_by_hw_breakpoint ()
2827 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2829 gdb_assert (lp
!= NULL
);
2831 return lp
->stop_reason
== TARGET_STOPPED_BY_HW_BREAKPOINT
;
2834 /* Implement the supports_stopped_by_hw_breakpoint method. */
2837 linux_nat_target::supports_stopped_by_hw_breakpoint ()
2839 return USE_SIGTRAP_SIGINFO
;
2842 /* Select one LWP out of those that have events pending. */
2845 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2848 int random_selector
;
2849 struct lwp_info
*event_lp
= NULL
;
2851 /* Record the wait status for the original LWP. */
2852 (*orig_lp
)->status
= *status
;
2854 /* In all-stop, give preference to the LWP that is being
2855 single-stepped. There will be at most one, and it will be the
2856 LWP that the core is most interested in. If we didn't do this,
2857 then we'd have to handle pending step SIGTRAPs somehow in case
2858 the core later continues the previously-stepped thread, as
2859 otherwise we'd report the pending SIGTRAP then, and the core, not
2860 having stepped the thread, wouldn't understand what the trap was
2861 for, and therefore would report it to the user as a random
2863 if (!target_is_non_stop_p ())
2865 event_lp
= iterate_over_lwps (filter
, select_singlestep_lwp_callback
);
2866 if (event_lp
!= NULL
)
2868 if (debug_linux_nat
)
2869 fprintf_unfiltered (gdb_stdlog
,
2870 "SEL: Select single-step %s\n",
2871 target_pid_to_str (event_lp
->ptid
).c_str ());
2875 if (event_lp
== NULL
)
2877 /* Pick one at random, out of those which have had events. */
2879 /* First see how many events we have. */
2880 iterate_over_lwps (filter
,
2881 [&] (struct lwp_info
*info
)
2883 return count_events_callback (info
, &num_events
);
2885 gdb_assert (num_events
> 0);
2887 /* Now randomly pick a LWP out of those that have had
2889 random_selector
= (int)
2890 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2892 if (debug_linux_nat
&& num_events
> 1)
2893 fprintf_unfiltered (gdb_stdlog
,
2894 "SEL: Found %d events, selecting #%d\n",
2895 num_events
, random_selector
);
2898 = (iterate_over_lwps
2900 [&] (struct lwp_info
*info
)
2902 return select_event_lwp_callback (info
,
2907 if (event_lp
!= NULL
)
2909 /* Switch the event LWP. */
2910 *orig_lp
= event_lp
;
2911 *status
= event_lp
->status
;
2914 /* Flush the wait status for the event LWP. */
2915 (*orig_lp
)->status
= 0;
2918 /* Return non-zero if LP has been resumed. */
2921 resumed_callback (struct lwp_info
*lp
)
2926 /* Check if we should go on and pass this event to common code.
2927 Return the affected lwp if we are, or NULL otherwise. */
2929 static struct lwp_info
*
2930 linux_nat_filter_event (int lwpid
, int status
)
2932 struct lwp_info
*lp
;
2933 int event
= linux_ptrace_get_extended_event (status
);
2935 lp
= find_lwp_pid (ptid_t (lwpid
));
2937 /* Check for stop events reported by a process we didn't already
2938 know about - anything not already in our LWP list.
2940 If we're expecting to receive stopped processes after
2941 fork, vfork, and clone events, then we'll just add the
2942 new one to our list and go back to waiting for the event
2943 to be reported - the stopped process might be returned
2944 from waitpid before or after the event is.
2946 But note the case of a non-leader thread exec'ing after the
2947 leader having exited, and gone from our lists. The non-leader
2948 thread changes its tid to the tgid. */
2950 if (WIFSTOPPED (status
) && lp
== NULL
2951 && (WSTOPSIG (status
) == SIGTRAP
&& event
== PTRACE_EVENT_EXEC
))
2953 /* A multi-thread exec after we had seen the leader exiting. */
2954 if (debug_linux_nat
)
2955 fprintf_unfiltered (gdb_stdlog
,
2956 "LLW: Re-adding thread group leader LWP %d.\n",
2959 lp
= add_lwp (ptid_t (lwpid
, lwpid
, 0));
2962 add_thread (lp
->ptid
);
2965 if (WIFSTOPPED (status
) && !lp
)
2967 if (debug_linux_nat
)
2968 fprintf_unfiltered (gdb_stdlog
,
2969 "LHEW: saving LWP %ld status %s in stopped_pids list\n",
2970 (long) lwpid
, status_to_str (status
));
2971 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2975 /* Make sure we don't report an event for the exit of an LWP not in
2976 our list, i.e. not part of the current process. This can happen
2977 if we detach from a program we originally forked and then it
2979 if (!WIFSTOPPED (status
) && !lp
)
2982 /* This LWP is stopped now. (And if dead, this prevents it from
2983 ever being continued.) */
2986 if (WIFSTOPPED (status
) && lp
->must_set_ptrace_flags
)
2988 struct inferior
*inf
= find_inferior_pid (lp
->ptid
.pid ());
2989 int options
= linux_nat_ptrace_options (inf
->attach_flag
);
2991 linux_enable_event_reporting (lp
->ptid
.lwp (), options
);
2992 lp
->must_set_ptrace_flags
= 0;
2995 /* Handle GNU/Linux's syscall SIGTRAPs. */
2996 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2998 /* No longer need the sysgood bit. The ptrace event ends up
2999 recorded in lp->waitstatus if we care for it. We can carry
3000 on handling the event like a regular SIGTRAP from here
3002 status
= W_STOPCODE (SIGTRAP
);
3003 if (linux_handle_syscall_trap (lp
, 0))
3008 /* Almost all other ptrace-stops are known to be outside of system
3009 calls, with further exceptions in linux_handle_extended_wait. */
3010 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
3013 /* Handle GNU/Linux's extended waitstatus for trace events. */
3014 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
3015 && linux_is_extended_waitstatus (status
))
3017 if (debug_linux_nat
)
3018 fprintf_unfiltered (gdb_stdlog
,
3019 "LLW: Handling extended status 0x%06x\n",
3021 if (linux_handle_extended_wait (lp
, status
))
3025 /* Check if the thread has exited. */
3026 if (WIFEXITED (status
) || WIFSIGNALED (status
))
3028 if (!report_thread_events
3029 && num_lwps (lp
->ptid
.pid ()) > 1)
3031 if (debug_linux_nat
)
3032 fprintf_unfiltered (gdb_stdlog
,
3033 "LLW: %s exited.\n",
3034 target_pid_to_str (lp
->ptid
).c_str ());
3036 /* If there is at least one more LWP, then the exit signal
3037 was not the end of the debugged application and should be
3043 /* Note that even if the leader was ptrace-stopped, it can still
3044 exit, if e.g., some other thread brings down the whole
3045 process (calls `exit'). So don't assert that the lwp is
3047 if (debug_linux_nat
)
3048 fprintf_unfiltered (gdb_stdlog
,
3049 "LWP %ld exited (resumed=%d)\n",
3050 lp
->ptid
.lwp (), lp
->resumed
);
3052 /* Dead LWP's aren't expected to reported a pending sigstop. */
3055 /* Store the pending event in the waitstatus, because
3056 W_EXITCODE(0,0) == 0. */
3057 store_waitstatus (&lp
->waitstatus
, status
);
3061 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3062 an attempt to stop an LWP. */
3064 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3068 if (lp
->last_resume_kind
== resume_stop
)
3070 if (debug_linux_nat
)
3071 fprintf_unfiltered (gdb_stdlog
,
3072 "LLW: resume_stop SIGSTOP caught for %s.\n",
3073 target_pid_to_str (lp
->ptid
).c_str ());
3077 /* This is a delayed SIGSTOP. Filter out the event. */
3079 if (debug_linux_nat
)
3080 fprintf_unfiltered (gdb_stdlog
,
3081 "LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
3083 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3084 target_pid_to_str (lp
->ptid
).c_str ());
3086 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3087 gdb_assert (lp
->resumed
);
3092 /* Make sure we don't report a SIGINT that we have already displayed
3093 for another thread. */
3094 if (lp
->ignore_sigint
3095 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3097 if (debug_linux_nat
)
3098 fprintf_unfiltered (gdb_stdlog
,
3099 "LLW: Delayed SIGINT caught for %s.\n",
3100 target_pid_to_str (lp
->ptid
).c_str ());
3102 /* This is a delayed SIGINT. */
3103 lp
->ignore_sigint
= 0;
3105 linux_resume_one_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
3106 if (debug_linux_nat
)
3107 fprintf_unfiltered (gdb_stdlog
,
3108 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3110 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3111 target_pid_to_str (lp
->ptid
).c_str ());
3112 gdb_assert (lp
->resumed
);
3114 /* Discard the event. */
3118 /* Don't report signals that GDB isn't interested in, such as
3119 signals that are neither printed nor stopped upon. Stopping all
3120 threads can be a bit time-consuming so if we want decent
3121 performance with heavily multi-threaded programs, especially when
3122 they're using a high frequency timer, we'd better avoid it if we
3124 if (WIFSTOPPED (status
))
3126 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3128 if (!target_is_non_stop_p ())
3130 /* Only do the below in all-stop, as we currently use SIGSTOP
3131 to implement target_stop (see linux_nat_stop) in
3133 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3135 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3136 forwarded to the entire process group, that is, all LWPs
3137 will receive it - unless they're using CLONE_THREAD to
3138 share signals. Since we only want to report it once, we
3139 mark it as ignored for all LWPs except this one. */
3140 iterate_over_lwps (ptid_t (lp
->ptid
.pid ()), set_ignore_sigint
);
3141 lp
->ignore_sigint
= 0;
3144 maybe_clear_ignore_sigint (lp
);
3147 /* When using hardware single-step, we need to report every signal.
3148 Otherwise, signals in pass_mask may be short-circuited
3149 except signals that might be caused by a breakpoint, or SIGSTOP
3150 if we sent the SIGSTOP and are waiting for it to arrive. */
3152 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
))
3153 && (WSTOPSIG (status
) != SIGSTOP
3154 || !find_thread_ptid (lp
->ptid
)->stop_requested
)
3155 && !linux_wstatus_maybe_breakpoint (status
))
3157 linux_resume_one_lwp (lp
, lp
->step
, signo
);
3158 if (debug_linux_nat
)
3159 fprintf_unfiltered (gdb_stdlog
,
3160 "LLW: %s %s, %s (preempt 'handle')\n",
3162 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3163 target_pid_to_str (lp
->ptid
).c_str (),
3164 (signo
!= GDB_SIGNAL_0
3165 ? strsignal (gdb_signal_to_host (signo
))
3171 /* An interesting event. */
3173 lp
->status
= status
;
3174 save_stop_reason (lp
);
3178 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3179 their exits until all other threads in the group have exited. */
3182 check_zombie_leaders (void)
3184 for (inferior
*inf
: all_inferiors ())
3186 struct lwp_info
*leader_lp
;
3191 leader_lp
= find_lwp_pid (ptid_t (inf
->pid
));
3192 if (leader_lp
!= NULL
3193 /* Check if there are other threads in the group, as we may
3194 have raced with the inferior simply exiting. */
3195 && num_lwps (inf
->pid
) > 1
3196 && linux_proc_pid_is_zombie (inf
->pid
))
3198 if (debug_linux_nat
)
3199 fprintf_unfiltered (gdb_stdlog
,
3200 "CZL: Thread group leader %d zombie "
3201 "(it exited, or another thread execd).\n",
3204 /* A leader zombie can mean one of two things:
3206 - It exited, and there's an exit status pending
3207 available, or only the leader exited (not the whole
3208 program). In the latter case, we can't waitpid the
3209 leader's exit status until all other threads are gone.
3211 - There are 3 or more threads in the group, and a thread
3212 other than the leader exec'd. See comments on exec
3213 events at the top of the file. We could try
3214 distinguishing the exit and exec cases, by waiting once
3215 more, and seeing if something comes out, but it doesn't
3216 sound useful. The previous leader _does_ go away, and
3217 we'll re-add the new one once we see the exec event
3218 (which is just the same as what would happen if the
3219 previous leader did exit voluntarily before some other
3222 if (debug_linux_nat
)
3223 fprintf_unfiltered (gdb_stdlog
,
3224 "CZL: Thread group leader %d vanished.\n",
3226 exit_lwp (leader_lp
);
3231 /* Convenience function that is called when the kernel reports an exit
3232 event. This decides whether to report the event to GDB as a
3233 process exit event, a thread exit event, or to suppress the
3237 filter_exit_event (struct lwp_info
*event_child
,
3238 struct target_waitstatus
*ourstatus
)
3240 ptid_t ptid
= event_child
->ptid
;
3242 if (num_lwps (ptid
.pid ()) > 1)
3244 if (report_thread_events
)
3245 ourstatus
->kind
= TARGET_WAITKIND_THREAD_EXITED
;
3247 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3249 exit_lwp (event_child
);
3256 linux_nat_wait_1 (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3260 enum resume_kind last_resume_kind
;
3261 struct lwp_info
*lp
;
3264 if (debug_linux_nat
)
3265 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3267 /* The first time we get here after starting a new inferior, we may
3268 not have added it to the LWP list yet - this is the earliest
3269 moment at which we know its PID. */
3270 if (inferior_ptid
.is_pid ())
3272 /* Upgrade the main thread's ptid. */
3273 thread_change_ptid (inferior_ptid
,
3274 ptid_t (inferior_ptid
.pid (),
3275 inferior_ptid
.pid (), 0));
3277 lp
= add_initial_lwp (inferior_ptid
);
3281 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3282 block_child_signals (&prev_mask
);
3284 /* First check if there is a LWP with a wait status pending. */
3285 lp
= iterate_over_lwps (ptid
, status_callback
);
3288 if (debug_linux_nat
)
3289 fprintf_unfiltered (gdb_stdlog
,
3290 "LLW: Using pending wait status %s for %s.\n",
3291 status_to_str (lp
->status
),
3292 target_pid_to_str (lp
->ptid
).c_str ());
3295 /* But if we don't find a pending event, we'll have to wait. Always
3296 pull all events out of the kernel. We'll randomly select an
3297 event LWP out of all that have events, to prevent starvation. */
3303 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3306 - If the thread group leader exits while other threads in the
3307 thread group still exist, waitpid(TGID, ...) hangs. That
3308 waitpid won't return an exit status until the other threads
3309 in the group are reaped.
3311 - When a non-leader thread execs, that thread just vanishes
3312 without reporting an exit (so we'd hang if we waited for it
3313 explicitly in that case). The exec event is reported to
3317 lwpid
= my_waitpid (-1, &status
, __WALL
| WNOHANG
);
3319 if (debug_linux_nat
)
3320 fprintf_unfiltered (gdb_stdlog
,
3321 "LNW: waitpid(-1, ...) returned %d, %s\n",
3322 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3326 if (debug_linux_nat
)
3328 fprintf_unfiltered (gdb_stdlog
,
3329 "LLW: waitpid %ld received %s\n",
3330 (long) lwpid
, status_to_str (status
));
3333 linux_nat_filter_event (lwpid
, status
);
3334 /* Retry until nothing comes out of waitpid. A single
3335 SIGCHLD can indicate more than one child stopped. */
3339 /* Now that we've pulled all events out of the kernel, resume
3340 LWPs that don't have an interesting event to report. */
3341 iterate_over_lwps (minus_one_ptid
,
3342 [] (struct lwp_info
*info
)
3344 return resume_stopped_resumed_lwps (info
, minus_one_ptid
);
3347 /* ... and find an LWP with a status to report to the core, if
3349 lp
= iterate_over_lwps (ptid
, status_callback
);
3353 /* Check for zombie thread group leaders. Those can't be reaped
3354 until all other threads in the thread group are. */
3355 check_zombie_leaders ();
3357 /* If there are no resumed children left, bail. We'd be stuck
3358 forever in the sigsuspend call below otherwise. */
3359 if (iterate_over_lwps (ptid
, resumed_callback
) == NULL
)
3361 if (debug_linux_nat
)
3362 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3364 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3366 restore_child_signals_mask (&prev_mask
);
3367 return minus_one_ptid
;
3370 /* No interesting event to report to the core. */
3372 if (target_options
& TARGET_WNOHANG
)
3374 if (debug_linux_nat
)
3375 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3377 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3378 restore_child_signals_mask (&prev_mask
);
3379 return minus_one_ptid
;
3382 /* We shouldn't end up here unless we want to try again. */
3383 gdb_assert (lp
== NULL
);
3385 /* Block until we get an event reported with SIGCHLD. */
3391 status
= lp
->status
;
3394 if (!target_is_non_stop_p ())
3396 /* Now stop all other LWP's ... */
3397 iterate_over_lwps (minus_one_ptid
, stop_callback
);
3399 /* ... and wait until all of them have reported back that
3400 they're no longer running. */
3401 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
);
3404 /* If we're not waiting for a specific LWP, choose an event LWP from
3405 among those that have had events. Giving equal priority to all
3406 LWPs that have had events helps prevent starvation. */
3407 if (ptid
== minus_one_ptid
|| ptid
.is_pid ())
3408 select_event_lwp (ptid
, &lp
, &status
);
3410 gdb_assert (lp
!= NULL
);
3412 /* Now that we've selected our final event LWP, un-adjust its PC if
3413 it was a software breakpoint, and we can't reliably support the
3414 "stopped by software breakpoint" stop reason. */
3415 if (lp
->stop_reason
== TARGET_STOPPED_BY_SW_BREAKPOINT
3416 && !USE_SIGTRAP_SIGINFO
)
3418 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3419 struct gdbarch
*gdbarch
= regcache
->arch ();
3420 int decr_pc
= gdbarch_decr_pc_after_break (gdbarch
);
3426 pc
= regcache_read_pc (regcache
);
3427 regcache_write_pc (regcache
, pc
+ decr_pc
);
3431 /* We'll need this to determine whether to report a SIGSTOP as
3432 GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
3434 last_resume_kind
= lp
->last_resume_kind
;
3436 if (!target_is_non_stop_p ())
3438 /* In all-stop, from the core's perspective, all LWPs are now
3439 stopped until a new resume action is sent over. */
3440 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
);
3444 resume_clear_callback (lp
);
3447 if (linux_target
->low_status_is_event (status
))
3449 if (debug_linux_nat
)
3450 fprintf_unfiltered (gdb_stdlog
,
3451 "LLW: trap ptid is %s.\n",
3452 target_pid_to_str (lp
->ptid
).c_str ());
3455 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3457 *ourstatus
= lp
->waitstatus
;
3458 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3461 store_waitstatus (ourstatus
, status
);
3463 if (debug_linux_nat
)
3464 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3466 restore_child_signals_mask (&prev_mask
);
3468 if (last_resume_kind
== resume_stop
3469 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3470 && WSTOPSIG (status
) == SIGSTOP
)
3472 /* A thread that has been requested to stop by GDB with
3473 target_stop, and it stopped cleanly, so report as SIG0. The
3474 use of SIGSTOP is an implementation detail. */
3475 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3478 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3479 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3482 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3484 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
)
3485 return filter_exit_event (lp
, ourstatus
);
3490 /* Resume LWPs that are currently stopped without any pending status
3491 to report, but are resumed from the core's perspective. */
3494 resume_stopped_resumed_lwps (struct lwp_info
*lp
, const ptid_t wait_ptid
)
3498 if (debug_linux_nat
)
3499 fprintf_unfiltered (gdb_stdlog
,
3500 "RSRL: NOT resuming LWP %s, not stopped\n",
3501 target_pid_to_str (lp
->ptid
).c_str ());
3503 else if (!lp
->resumed
)
3505 if (debug_linux_nat
)
3506 fprintf_unfiltered (gdb_stdlog
,
3507 "RSRL: NOT resuming LWP %s, not resumed\n",
3508 target_pid_to_str (lp
->ptid
).c_str ());
3510 else if (lwp_status_pending_p (lp
))
3512 if (debug_linux_nat
)
3513 fprintf_unfiltered (gdb_stdlog
,
3514 "RSRL: NOT resuming LWP %s, has pending status\n",
3515 target_pid_to_str (lp
->ptid
).c_str ());
3519 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3520 struct gdbarch
*gdbarch
= regcache
->arch ();
3524 CORE_ADDR pc
= regcache_read_pc (regcache
);
3525 int leave_stopped
= 0;
3527 /* Don't bother if there's a breakpoint at PC that we'd hit
3528 immediately, and we're not waiting for this LWP. */
3529 if (!lp
->ptid
.matches (wait_ptid
))
3531 if (breakpoint_inserted_here_p (regcache
->aspace (), pc
))
3537 if (debug_linux_nat
)
3538 fprintf_unfiltered (gdb_stdlog
,
3539 "RSRL: resuming stopped-resumed LWP %s at "
3541 target_pid_to_str (lp
->ptid
).c_str (),
3542 paddress (gdbarch
, pc
),
3545 linux_resume_one_lwp_throw (lp
, lp
->step
, GDB_SIGNAL_0
);
3548 catch (const gdb_exception_error
&ex
)
3550 if (!check_ptrace_stopped_lwp_gone (lp
))
3559 linux_nat_target::wait (ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3564 if (debug_linux_nat
)
3566 std::string options_string
= target_options_to_string (target_options
);
3567 fprintf_unfiltered (gdb_stdlog
,
3568 "linux_nat_wait: [%s], [%s]\n",
3569 target_pid_to_str (ptid
).c_str (),
3570 options_string
.c_str ());
3573 /* Flush the async file first. */
3574 if (target_is_async_p ())
3575 async_file_flush ();
3577 /* Resume LWPs that are currently stopped without any pending status
3578 to report, but are resumed from the core's perspective. LWPs get
3579 in this state if we find them stopping at a time we're not
3580 interested in reporting the event (target_wait on a
3581 specific_process, for example, see linux_nat_wait_1), and
3582 meanwhile the event became uninteresting. Don't bother resuming
3583 LWPs we're not going to wait for if they'd stop immediately. */
3584 if (target_is_non_stop_p ())
3585 iterate_over_lwps (minus_one_ptid
,
3586 [=] (struct lwp_info
*info
)
3588 return resume_stopped_resumed_lwps (info
, ptid
);
3591 event_ptid
= linux_nat_wait_1 (ptid
, ourstatus
, target_options
);
3593 /* If we requested any event, and something came out, assume there
3594 may be more. If we requested a specific lwp or process, also
3595 assume there may be more. */
3596 if (target_is_async_p ()
3597 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3598 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3599 || ptid
!= minus_one_ptid
))
3608 kill_one_lwp (pid_t pid
)
3610 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3613 kill_lwp (pid
, SIGKILL
);
3614 if (debug_linux_nat
)
3616 int save_errno
= errno
;
3618 fprintf_unfiltered (gdb_stdlog
,
3619 "KC: kill (SIGKILL) %ld, 0, 0 (%s)\n", (long) pid
,
3620 save_errno
? safe_strerror (save_errno
) : "OK");
3623 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3626 ptrace (PTRACE_KILL
, pid
, 0, 0);
3627 if (debug_linux_nat
)
3629 int save_errno
= errno
;
3631 fprintf_unfiltered (gdb_stdlog
,
3632 "KC: PTRACE_KILL %ld, 0, 0 (%s)\n", (long) pid
,
3633 save_errno
? safe_strerror (save_errno
) : "OK");
3637 /* Wait for an LWP to die. */
3640 kill_wait_one_lwp (pid_t pid
)
3644 /* We must make sure that there are no pending events (delayed
3645 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3646 program doesn't interfere with any following debugging session. */
3650 res
= my_waitpid (pid
, NULL
, __WALL
);
3651 if (res
!= (pid_t
) -1)
3653 if (debug_linux_nat
)
3654 fprintf_unfiltered (gdb_stdlog
,
3655 "KWC: wait %ld received unknown.\n",
3657 /* The Linux kernel sometimes fails to kill a thread
3658 completely after PTRACE_KILL; that goes from the stop
3659 point in do_fork out to the one in get_signal_to_deliver
3660 and waits again. So kill it again. */
3666 gdb_assert (res
== -1 && errno
== ECHILD
);
3669 /* Callback for iterate_over_lwps. */
3672 kill_callback (struct lwp_info
*lp
)
3674 kill_one_lwp (lp
->ptid
.lwp ());
3678 /* Callback for iterate_over_lwps. */
3681 kill_wait_callback (struct lwp_info
*lp
)
3683 kill_wait_one_lwp (lp
->ptid
.lwp ());
3687 /* Kill the fork children of any threads of inferior INF that are
3688 stopped at a fork event. */
3691 kill_unfollowed_fork_children (struct inferior
*inf
)
3693 for (thread_info
*thread
: inf
->non_exited_threads ())
3695 struct target_waitstatus
*ws
= &thread
->pending_follow
;
3697 if (ws
->kind
== TARGET_WAITKIND_FORKED
3698 || ws
->kind
== TARGET_WAITKIND_VFORKED
)
3700 ptid_t child_ptid
= ws
->value
.related_pid
;
3701 int child_pid
= child_ptid
.pid ();
3702 int child_lwp
= child_ptid
.lwp ();
3704 kill_one_lwp (child_lwp
);
3705 kill_wait_one_lwp (child_lwp
);
3707 /* Let the arch-specific native code know this process is
3709 linux_target
->low_forget_process (child_pid
);
3715 linux_nat_target::kill ()
3717 /* If we're stopped while forking and we haven't followed yet,
3718 kill the other task. We need to do this first because the
3719 parent will be sleeping if this is a vfork. */
3720 kill_unfollowed_fork_children (current_inferior ());
3722 if (forks_exist_p ())
3723 linux_fork_killall ();
3726 ptid_t ptid
= ptid_t (inferior_ptid
.pid ());
3728 /* Stop all threads before killing them, since ptrace requires
3729 that the thread is stopped to successfully PTRACE_KILL. */
3730 iterate_over_lwps (ptid
, stop_callback
);
3731 /* ... and wait until all of them have reported back that
3732 they're no longer running. */
3733 iterate_over_lwps (ptid
, stop_wait_callback
);
3735 /* Kill all LWP's ... */
3736 iterate_over_lwps (ptid
, kill_callback
);
3738 /* ... and wait until we've flushed all events. */
3739 iterate_over_lwps (ptid
, kill_wait_callback
);
3742 target_mourn_inferior (inferior_ptid
);
3746 linux_nat_target::mourn_inferior ()
3748 int pid
= inferior_ptid
.pid ();
3750 purge_lwp_list (pid
);
3752 if (! forks_exist_p ())
3753 /* Normal case, no other forks available. */
3754 inf_ptrace_target::mourn_inferior ();
3756 /* Multi-fork case. The current inferior_ptid has exited, but
3757 there are other viable forks to debug. Delete the exiting
3758 one and context-switch to the first available. */
3759 linux_fork_mourn_inferior ();
3761 /* Let the arch-specific native code know this process is gone. */
3762 linux_target
->low_forget_process (pid
);
3765 /* Convert a native/host siginfo object, into/from the siginfo in the
3766 layout of the inferiors' architecture. */
3769 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3771 /* If the low target didn't do anything, then just do a straight
3773 if (!linux_target
->low_siginfo_fixup (siginfo
, inf_siginfo
, direction
))
3776 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3778 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3782 static enum target_xfer_status
3783 linux_xfer_siginfo (enum target_object object
,
3784 const char *annex
, gdb_byte
*readbuf
,
3785 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3786 ULONGEST
*xfered_len
)
3790 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3792 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3793 gdb_assert (readbuf
|| writebuf
);
3795 pid
= inferior_ptid
.lwp ();
3797 pid
= inferior_ptid
.pid ();
3799 if (offset
> sizeof (siginfo
))
3800 return TARGET_XFER_E_IO
;
3803 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3805 return TARGET_XFER_E_IO
;
3807 /* When GDB is built as a 64-bit application, ptrace writes into
3808 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3809 inferior with a 64-bit GDB should look the same as debugging it
3810 with a 32-bit GDB, we need to convert it. GDB core always sees
3811 the converted layout, so any read/write will have to be done
3813 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3815 if (offset
+ len
> sizeof (siginfo
))
3816 len
= sizeof (siginfo
) - offset
;
3818 if (readbuf
!= NULL
)
3819 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3822 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3824 /* Convert back to ptrace layout before flushing it out. */
3825 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3828 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3830 return TARGET_XFER_E_IO
;
3834 return TARGET_XFER_OK
;
3837 static enum target_xfer_status
3838 linux_nat_xfer_osdata (enum target_object object
,
3839 const char *annex
, gdb_byte
*readbuf
,
3840 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3841 ULONGEST
*xfered_len
);
3843 static enum target_xfer_status
3844 linux_proc_xfer_partial (enum target_object object
,
3845 const char *annex
, gdb_byte
*readbuf
,
3846 const gdb_byte
*writebuf
,
3847 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
);
3849 enum target_xfer_status
3850 linux_nat_target::xfer_partial (enum target_object object
,
3851 const char *annex
, gdb_byte
*readbuf
,
3852 const gdb_byte
*writebuf
,
3853 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3855 enum target_xfer_status xfer
;
3857 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3858 return linux_xfer_siginfo (object
, annex
, readbuf
, writebuf
,
3859 offset
, len
, xfered_len
);
3861 /* The target is connected but no live inferior is selected. Pass
3862 this request down to a lower stratum (e.g., the executable
3864 if (object
== TARGET_OBJECT_MEMORY
&& inferior_ptid
== null_ptid
)
3865 return TARGET_XFER_EOF
;
3867 if (object
== TARGET_OBJECT_AUXV
)
3868 return memory_xfer_auxv (this, object
, annex
, readbuf
, writebuf
,
3869 offset
, len
, xfered_len
);
3871 if (object
== TARGET_OBJECT_OSDATA
)
3872 return linux_nat_xfer_osdata (object
, annex
, readbuf
, writebuf
,
3873 offset
, len
, xfered_len
);
3875 /* GDB calculates all addresses in the largest possible address
3877 The address width must be masked before its final use - either by
3878 linux_proc_xfer_partial or inf_ptrace_target::xfer_partial.
3880 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
3882 if (object
== TARGET_OBJECT_MEMORY
)
3884 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
3886 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
3887 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
3890 xfer
= linux_proc_xfer_partial (object
, annex
, readbuf
, writebuf
,
3891 offset
, len
, xfered_len
);
3892 if (xfer
!= TARGET_XFER_EOF
)
3895 return inf_ptrace_target::xfer_partial (object
, annex
, readbuf
, writebuf
,
3896 offset
, len
, xfered_len
);
3900 linux_nat_target::thread_alive (ptid_t ptid
)
3902 /* As long as a PTID is in lwp list, consider it alive. */
3903 return find_lwp_pid (ptid
) != NULL
;
3906 /* Implement the to_update_thread_list target method for this
3910 linux_nat_target::update_thread_list ()
3912 struct lwp_info
*lwp
;
3914 /* We add/delete threads from the list as clone/exit events are
3915 processed, so just try deleting exited threads still in the
3917 delete_exited_threads ();
3919 /* Update the processor core that each lwp/thread was last seen
3923 /* Avoid accessing /proc if the thread hasn't run since we last
3924 time we fetched the thread's core. Accessing /proc becomes
3925 noticeably expensive when we have thousands of LWPs. */
3926 if (lwp
->core
== -1)
3927 lwp
->core
= linux_common_core_of_thread (lwp
->ptid
);
3932 linux_nat_target::pid_to_str (ptid_t ptid
)
3935 && (ptid
.pid () != ptid
.lwp ()
3936 || num_lwps (ptid
.pid ()) > 1))
3937 return string_printf ("LWP %ld", ptid
.lwp ());
3939 return normal_pid_to_str (ptid
);
3943 linux_nat_target::thread_name (struct thread_info
*thr
)
3945 return linux_proc_tid_get_name (thr
->ptid
);
3948 /* Accepts an integer PID; Returns a string representing a file that
3949 can be opened to get the symbols for the child process. */
3952 linux_nat_target::pid_to_exec_file (int pid
)
3954 return linux_proc_pid_to_exec_file (pid
);
3957 /* Implement the to_xfer_partial target method using /proc/<pid>/mem.
3958 Because we can use a single read/write call, this can be much more
3959 efficient than banging away at PTRACE_PEEKTEXT. */
3961 static enum target_xfer_status
3962 linux_proc_xfer_partial (enum target_object object
,
3963 const char *annex
, gdb_byte
*readbuf
,
3964 const gdb_byte
*writebuf
,
3965 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
3971 if (object
!= TARGET_OBJECT_MEMORY
)
3972 return TARGET_XFER_EOF
;
3974 /* Don't bother for one word. */
3975 if (len
< 3 * sizeof (long))
3976 return TARGET_XFER_EOF
;
3978 /* We could keep this file open and cache it - possibly one per
3979 thread. That requires some juggling, but is even faster. */
3980 xsnprintf (filename
, sizeof filename
, "/proc/%ld/mem",
3981 inferior_ptid
.lwp ());
3982 fd
= gdb_open_cloexec (filename
, ((readbuf
? O_RDONLY
: O_WRONLY
)
3985 return TARGET_XFER_EOF
;
3987 /* Use pread64/pwrite64 if available, since they save a syscall and can
3988 handle 64-bit offsets even on 32-bit platforms (for instance, SPARC
3989 debugging a SPARC64 application). */
3991 ret
= (readbuf
? pread64 (fd
, readbuf
, len
, offset
)
3992 : pwrite64 (fd
, writebuf
, len
, offset
));
3994 ret
= lseek (fd
, offset
, SEEK_SET
);
3996 ret
= (readbuf
? read (fd
, readbuf
, len
)
3997 : write (fd
, writebuf
, len
));
4002 if (ret
== -1 || ret
== 0)
4003 return TARGET_XFER_EOF
;
4007 return TARGET_XFER_OK
;
4012 /* Parse LINE as a signal set and add its set bits to SIGS. */
4015 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4017 int len
= strlen (line
) - 1;
4021 if (line
[len
] != '\n')
4022 error (_("Could not parse signal set: %s"), line
);
4030 if (*p
>= '0' && *p
<= '9')
4032 else if (*p
>= 'a' && *p
<= 'f')
4033 digit
= *p
- 'a' + 10;
4035 error (_("Could not parse signal set: %s"), line
);
4040 sigaddset (sigs
, signum
+ 1);
4042 sigaddset (sigs
, signum
+ 2);
4044 sigaddset (sigs
, signum
+ 3);
4046 sigaddset (sigs
, signum
+ 4);
4052 /* Find process PID's pending signals from /proc/pid/status and set
4056 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4057 sigset_t
*blocked
, sigset_t
*ignored
)
4059 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4061 sigemptyset (pending
);
4062 sigemptyset (blocked
);
4063 sigemptyset (ignored
);
4064 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4065 gdb_file_up procfile
= gdb_fopen_cloexec (fname
, "r");
4066 if (procfile
== NULL
)
4067 error (_("Could not open %s"), fname
);
4069 while (fgets (buffer
, PATH_MAX
, procfile
.get ()) != NULL
)
4071 /* Normal queued signals are on the SigPnd line in the status
4072 file. However, 2.6 kernels also have a "shared" pending
4073 queue for delivering signals to a thread group, so check for
4076 Unfortunately some Red Hat kernels include the shared pending
4077 queue but not the ShdPnd status field. */
4079 if (startswith (buffer
, "SigPnd:\t"))
4080 add_line_to_sigset (buffer
+ 8, pending
);
4081 else if (startswith (buffer
, "ShdPnd:\t"))
4082 add_line_to_sigset (buffer
+ 8, pending
);
4083 else if (startswith (buffer
, "SigBlk:\t"))
4084 add_line_to_sigset (buffer
+ 8, blocked
);
4085 else if (startswith (buffer
, "SigIgn:\t"))
4086 add_line_to_sigset (buffer
+ 8, ignored
);
4090 static enum target_xfer_status
4091 linux_nat_xfer_osdata (enum target_object object
,
4092 const char *annex
, gdb_byte
*readbuf
,
4093 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4094 ULONGEST
*xfered_len
)
4096 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4098 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4099 if (*xfered_len
== 0)
4100 return TARGET_XFER_EOF
;
4102 return TARGET_XFER_OK
;
4105 std::vector
<static_tracepoint_marker
>
4106 linux_nat_target::static_tracepoint_markers_by_strid (const char *strid
)
4108 char s
[IPA_CMD_BUF_SIZE
];
4109 int pid
= inferior_ptid
.pid ();
4110 std::vector
<static_tracepoint_marker
> markers
;
4112 ptid_t ptid
= ptid_t (pid
, 0, 0);
4113 static_tracepoint_marker marker
;
4118 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4119 s
[sizeof ("qTfSTM")] = 0;
4121 agent_run_command (pid
, s
, strlen (s
) + 1);
4124 SCOPE_EXIT
{ target_continue_no_signal (ptid
); };
4130 parse_static_tracepoint_marker_definition (p
, &p
, &marker
);
4132 if (strid
== NULL
|| marker
.str_id
== strid
)
4133 markers
.push_back (std::move (marker
));
4135 while (*p
++ == ','); /* comma-separated list */
4137 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4138 s
[sizeof ("qTsSTM")] = 0;
4139 agent_run_command (pid
, s
, strlen (s
) + 1);
4146 /* target_is_async_p implementation. */
4149 linux_nat_target::is_async_p ()
4151 return linux_is_async_p ();
4154 /* target_can_async_p implementation. */
4157 linux_nat_target::can_async_p ()
4159 /* We're always async, unless the user explicitly prevented it with the
4160 "maint set target-async" command. */
4161 return target_async_permitted
;
4165 linux_nat_target::supports_non_stop ()
4170 /* to_always_non_stop_p implementation. */
4173 linux_nat_target::always_non_stop_p ()
4178 /* True if we want to support multi-process. To be removed when GDB
4179 supports multi-exec. */
4181 int linux_multi_process
= 1;
4184 linux_nat_target::supports_multi_process ()
4186 return linux_multi_process
;
4190 linux_nat_target::supports_disable_randomization ()
4192 #ifdef HAVE_PERSONALITY
4199 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4200 so we notice when any child changes state, and notify the
4201 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4202 above to wait for the arrival of a SIGCHLD. */
4205 sigchld_handler (int signo
)
4207 int old_errno
= errno
;
4209 if (debug_linux_nat
)
4210 ui_file_write_async_safe (gdb_stdlog
,
4211 "sigchld\n", sizeof ("sigchld\n") - 1);
4213 if (signo
== SIGCHLD
4214 && linux_nat_event_pipe
[0] != -1)
4215 async_file_mark (); /* Let the event loop know that there are
4216 events to handle. */
4221 /* Callback registered with the target events file descriptor. */
4224 handle_target_event (int error
, gdb_client_data client_data
)
4226 inferior_event_handler (INF_REG_EVENT
, NULL
);
4229 /* Create/destroy the target events pipe. Returns previous state. */
4232 linux_async_pipe (int enable
)
4234 int previous
= linux_is_async_p ();
4236 if (previous
!= enable
)
4240 /* Block child signals while we create/destroy the pipe, as
4241 their handler writes to it. */
4242 block_child_signals (&prev_mask
);
4246 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4247 internal_error (__FILE__
, __LINE__
,
4248 "creating event pipe failed.");
4250 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4251 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4255 close (linux_nat_event_pipe
[0]);
4256 close (linux_nat_event_pipe
[1]);
4257 linux_nat_event_pipe
[0] = -1;
4258 linux_nat_event_pipe
[1] = -1;
4261 restore_child_signals_mask (&prev_mask
);
4267 /* target_async implementation. */
4270 linux_nat_target::async (int enable
)
4274 if (!linux_async_pipe (1))
4276 add_file_handler (linux_nat_event_pipe
[0],
4277 handle_target_event
, NULL
);
4278 /* There may be pending events to handle. Tell the event loop
4285 delete_file_handler (linux_nat_event_pipe
[0]);
4286 linux_async_pipe (0);
4291 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4295 linux_nat_stop_lwp (struct lwp_info
*lwp
)
4299 if (debug_linux_nat
)
4300 fprintf_unfiltered (gdb_stdlog
,
4301 "LNSL: running -> suspending %s\n",
4302 target_pid_to_str (lwp
->ptid
).c_str ());
4305 if (lwp
->last_resume_kind
== resume_stop
)
4307 if (debug_linux_nat
)
4308 fprintf_unfiltered (gdb_stdlog
,
4309 "linux-nat: already stopping LWP %ld at "
4315 stop_callback (lwp
);
4316 lwp
->last_resume_kind
= resume_stop
;
4320 /* Already known to be stopped; do nothing. */
4322 if (debug_linux_nat
)
4324 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4325 fprintf_unfiltered (gdb_stdlog
,
4326 "LNSL: already stopped/stop_requested %s\n",
4327 target_pid_to_str (lwp
->ptid
).c_str ());
4329 fprintf_unfiltered (gdb_stdlog
,
4330 "LNSL: already stopped/no "
4331 "stop_requested yet %s\n",
4332 target_pid_to_str (lwp
->ptid
).c_str ());
4339 linux_nat_target::stop (ptid_t ptid
)
4341 iterate_over_lwps (ptid
, linux_nat_stop_lwp
);
4345 linux_nat_target::close ()
4347 /* Unregister from the event loop. */
4351 inf_ptrace_target::close ();
4354 /* When requests are passed down from the linux-nat layer to the
4355 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4356 used. The address space pointer is stored in the inferior object,
4357 but the common code that is passed such ptid can't tell whether
4358 lwpid is a "main" process id or not (it assumes so). We reverse
4359 look up the "main" process id from the lwp here. */
4361 struct address_space
*
4362 linux_nat_target::thread_address_space (ptid_t ptid
)
4364 struct lwp_info
*lwp
;
4365 struct inferior
*inf
;
4368 if (ptid
.lwp () == 0)
4370 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4372 lwp
= find_lwp_pid (ptid
);
4373 pid
= lwp
->ptid
.pid ();
4377 /* A (pid,lwpid,0) ptid. */
4381 inf
= find_inferior_pid (pid
);
4382 gdb_assert (inf
!= NULL
);
4386 /* Return the cached value of the processor core for thread PTID. */
4389 linux_nat_target::core_of_thread (ptid_t ptid
)
4391 struct lwp_info
*info
= find_lwp_pid (ptid
);
4398 /* Implementation of to_filesystem_is_local. */
4401 linux_nat_target::filesystem_is_local ()
4403 struct inferior
*inf
= current_inferior ();
4405 if (inf
->fake_pid_p
|| inf
->pid
== 0)
4408 return linux_ns_same (inf
->pid
, LINUX_NS_MNT
);
4411 /* Convert the INF argument passed to a to_fileio_* method
4412 to a process ID suitable for passing to its corresponding
4413 linux_mntns_* function. If INF is non-NULL then the
4414 caller is requesting the filesystem seen by INF. If INF
4415 is NULL then the caller is requesting the filesystem seen
4416 by the GDB. We fall back to GDB's filesystem in the case
4417 that INF is non-NULL but its PID is unknown. */
4420 linux_nat_fileio_pid_of (struct inferior
*inf
)
4422 if (inf
== NULL
|| inf
->fake_pid_p
|| inf
->pid
== 0)
4428 /* Implementation of to_fileio_open. */
4431 linux_nat_target::fileio_open (struct inferior
*inf
, const char *filename
,
4432 int flags
, int mode
, int warn_if_slow
,
4439 if (fileio_to_host_openflags (flags
, &nat_flags
) == -1
4440 || fileio_to_host_mode (mode
, &nat_mode
) == -1)
4442 *target_errno
= FILEIO_EINVAL
;
4446 fd
= linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf
),
4447 filename
, nat_flags
, nat_mode
);
4449 *target_errno
= host_to_fileio_error (errno
);
4454 /* Implementation of to_fileio_readlink. */
4456 gdb::optional
<std::string
>
4457 linux_nat_target::fileio_readlink (struct inferior
*inf
, const char *filename
,
4463 len
= linux_mntns_readlink (linux_nat_fileio_pid_of (inf
),
4464 filename
, buf
, sizeof (buf
));
4467 *target_errno
= host_to_fileio_error (errno
);
4471 return std::string (buf
, len
);
4474 /* Implementation of to_fileio_unlink. */
4477 linux_nat_target::fileio_unlink (struct inferior
*inf
, const char *filename
,
4482 ret
= linux_mntns_unlink (linux_nat_fileio_pid_of (inf
),
4485 *target_errno
= host_to_fileio_error (errno
);
4490 /* Implementation of the to_thread_events method. */
4493 linux_nat_target::thread_events (int enable
)
4495 report_thread_events
= enable
;
4498 linux_nat_target::linux_nat_target ()
4500 /* We don't change the stratum; this target will sit at
4501 process_stratum and thread_db will set at thread_stratum. This
4502 is a little strange, since this is a multi-threaded-capable
4503 target, but we want to be on the stack below thread_db, and we
4504 also want to be used for single-threaded processes. */
4507 /* See linux-nat.h. */
4510 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4519 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4522 memset (siginfo
, 0, sizeof (*siginfo
));
4528 /* See nat/linux-nat.h. */
4531 current_lwp_ptid (void)
4533 gdb_assert (inferior_ptid
.lwp_p ());
4534 return inferior_ptid
;
4538 _initialize_linux_nat (void)
4540 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4541 &debug_linux_nat
, _("\
4542 Set debugging of GNU/Linux lwp module."), _("\
4543 Show debugging of GNU/Linux lwp module."), _("\
4544 Enables printf debugging output."),
4546 show_debug_linux_nat
,
4547 &setdebuglist
, &showdebuglist
);
4549 add_setshow_boolean_cmd ("linux-namespaces", class_maintenance
,
4550 &debug_linux_namespaces
, _("\
4551 Set debugging of GNU/Linux namespaces module."), _("\
4552 Show debugging of GNU/Linux namespaces module."), _("\
4553 Enables printf debugging output."),
4556 &setdebuglist
, &showdebuglist
);
4558 /* Install a SIGCHLD handler. */
4559 sigchld_action
.sa_handler
= sigchld_handler
;
4560 sigemptyset (&sigchld_action
.sa_mask
);
4561 sigchld_action
.sa_flags
= SA_RESTART
;
4563 /* Make it the default. */
4564 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4566 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4567 gdb_sigmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4568 sigdelset (&suspend_mask
, SIGCHLD
);
4570 sigemptyset (&blocked_mask
);
4572 lwp_lwpid_htab_create ();
4576 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4577 the GNU/Linux Threads library and therefore doesn't really belong
4580 /* Return the set of signals used by the threads library in *SET. */
4583 lin_thread_get_thread_signals (sigset_t
*set
)
4587 /* NPTL reserves the first two RT signals, but does not provide any
4588 way for the debugger to query the signal numbers - fortunately
4589 they don't change. */
4590 sigaddset (set
, __SIGRTMIN
);
4591 sigaddset (set
, __SIGRTMIN
+ 1);