1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2014 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"
28 #ifdef HAVE_TKILL_SYSCALL
30 #include <sys/syscall.h>
32 #include <sys/ptrace.h>
33 #include "linux-nat.h"
34 #include "nat/linux-ptrace.h"
35 #include "nat/linux-procfs.h"
36 #include "linux-fork.h"
37 #include "gdbthread.h"
41 #include "inf-child.h"
42 #include "inf-ptrace.h"
44 #include <sys/procfs.h> /* for elf_gregset etc. */
45 #include "elf-bfd.h" /* for elfcore_write_* */
46 #include "gregset.h" /* for gregset */
47 #include "gdbcore.h" /* for get_exec_file */
48 #include <ctype.h> /* for isdigit */
49 #include <sys/stat.h> /* for struct stat */
50 #include <fcntl.h> /* for O_RDONLY */
52 #include "event-loop.h"
53 #include "event-top.h"
55 #include <sys/types.h>
57 #include "xml-support.h"
61 #include "nat/linux-osdata.h"
62 #include "linux-tdep.h"
65 #include "tracepoint.h"
66 #include "exceptions.h"
68 #include "target-descriptions.h"
69 #include "filestuff.h"
73 #define SPUFS_MAGIC 0x23c9b64e
76 #ifdef HAVE_PERSONALITY
77 # include <sys/personality.h>
78 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
79 # define ADDR_NO_RANDOMIZE 0x0040000
81 #endif /* HAVE_PERSONALITY */
83 /* This comment documents high-level logic of this file.
85 Waiting for events in sync mode
86 ===============================
88 When waiting for an event in a specific thread, we just use waitpid, passing
89 the specific pid, and not passing WNOHANG.
91 When waiting for an event in all threads, waitpid is not quite good. Prior to
92 version 2.4, Linux can either wait for event in main thread, or in secondary
93 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
94 miss an event. The solution is to use non-blocking waitpid, together with
95 sigsuspend. First, we use non-blocking waitpid to get an event in the main
96 process, if any. Second, we use non-blocking waitpid with the __WCLONED
97 flag to check for events in cloned processes. If nothing is found, we use
98 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
99 happened to a child process -- and SIGCHLD will be delivered both for events
100 in main debugged process and in cloned processes. As soon as we know there's
101 an event, we get back to calling nonblocking waitpid with and without
104 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
105 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
106 blocked, the signal becomes pending and sigsuspend immediately
107 notices it and returns.
109 Waiting for events in async mode
110 ================================
112 In async mode, GDB should always be ready to handle both user input
113 and target events, so neither blocking waitpid nor sigsuspend are
114 viable options. Instead, we should asynchronously notify the GDB main
115 event loop whenever there's an unprocessed event from the target. We
116 detect asynchronous target events by handling SIGCHLD signals. To
117 notify the event loop about target events, the self-pipe trick is used
118 --- a pipe is registered as waitable event source in the event loop,
119 the event loop select/poll's on the read end of this pipe (as well on
120 other event sources, e.g., stdin), and the SIGCHLD handler writes a
121 byte to this pipe. This is more portable than relying on
122 pselect/ppoll, since on kernels that lack those syscalls, libc
123 emulates them with select/poll+sigprocmask, and that is racy
124 (a.k.a. plain broken).
126 Obviously, if we fail to notify the event loop if there's a target
127 event, it's bad. OTOH, if we notify the event loop when there's no
128 event from the target, linux_nat_wait will detect that there's no real
129 event to report, and return event of type TARGET_WAITKIND_IGNORE.
130 This is mostly harmless, but it will waste time and is better avoided.
132 The main design point is that every time GDB is outside linux-nat.c,
133 we have a SIGCHLD handler installed that is called when something
134 happens to the target and notifies the GDB event loop. Whenever GDB
135 core decides to handle the event, and calls into linux-nat.c, we
136 process things as in sync mode, except that the we never block in
139 While processing an event, we may end up momentarily blocked in
140 waitpid calls. Those waitpid calls, while blocking, are guarantied to
141 return quickly. E.g., in all-stop mode, before reporting to the core
142 that an LWP hit a breakpoint, all LWPs are stopped by sending them
143 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
144 Note that this is different from blocking indefinitely waiting for the
145 next event --- here, we're already handling an event.
150 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
151 signal is not entirely significant; we just need for a signal to be delivered,
152 so that we can intercept it. SIGSTOP's advantage is that it can not be
153 blocked. A disadvantage is that it is not a real-time signal, so it can only
154 be queued once; we do not keep track of other sources of SIGSTOP.
156 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
157 use them, because they have special behavior when the signal is generated -
158 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
159 kills the entire thread group.
161 A delivered SIGSTOP would stop the entire thread group, not just the thread we
162 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
163 cancel it (by PTRACE_CONT without passing SIGSTOP).
165 We could use a real-time signal instead. This would solve those problems; we
166 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
167 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
168 generates it, and there are races with trying to find a signal that is not
172 #define O_LARGEFILE 0
175 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
176 the use of the multi-threaded target. */
177 static struct target_ops
*linux_ops
;
178 static struct target_ops linux_ops_saved
;
180 /* The method to call, if any, when a new thread is attached. */
181 static void (*linux_nat_new_thread
) (struct lwp_info
*);
183 /* The method to call, if any, when a new fork is attached. */
184 static linux_nat_new_fork_ftype
*linux_nat_new_fork
;
186 /* The method to call, if any, when a process is no longer
188 static linux_nat_forget_process_ftype
*linux_nat_forget_process_hook
;
190 /* Hook to call prior to resuming a thread. */
191 static void (*linux_nat_prepare_to_resume
) (struct lwp_info
*);
193 /* The method to call, if any, when the siginfo object needs to be
194 converted between the layout returned by ptrace, and the layout in
195 the architecture of the inferior. */
196 static int (*linux_nat_siginfo_fixup
) (siginfo_t
*,
200 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
201 Called by our to_xfer_partial. */
202 static target_xfer_partial_ftype
*super_xfer_partial
;
204 /* The saved to_close method, inherited from inf-ptrace.c.
205 Called by our to_close. */
206 static void (*super_close
) (struct target_ops
*);
208 static unsigned int debug_linux_nat
;
210 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
211 struct cmd_list_element
*c
, const char *value
)
213 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
217 struct simple_pid_list
221 struct simple_pid_list
*next
;
223 struct simple_pid_list
*stopped_pids
;
225 /* Async mode support. */
227 /* The read/write ends of the pipe registered as waitable file in the
229 static int linux_nat_event_pipe
[2] = { -1, -1 };
231 /* Flush the event pipe. */
234 async_file_flush (void)
241 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
243 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
246 /* Put something (anything, doesn't matter what, or how much) in event
247 pipe, so that the select/poll in the event-loop realizes we have
248 something to process. */
251 async_file_mark (void)
255 /* It doesn't really matter what the pipe contains, as long we end
256 up with something in it. Might as well flush the previous
262 ret
= write (linux_nat_event_pipe
[1], "+", 1);
264 while (ret
== -1 && errno
== EINTR
);
266 /* Ignore EAGAIN. If the pipe is full, the event loop will already
267 be awakened anyway. */
270 static int kill_lwp (int lwpid
, int signo
);
272 static int stop_callback (struct lwp_info
*lp
, void *data
);
274 static void block_child_signals (sigset_t
*prev_mask
);
275 static void restore_child_signals_mask (sigset_t
*prev_mask
);
278 static struct lwp_info
*add_lwp (ptid_t ptid
);
279 static void purge_lwp_list (int pid
);
280 static void delete_lwp (ptid_t ptid
);
281 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
284 /* Trivial list manipulation functions to keep track of a list of
285 new stopped processes. */
287 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
289 struct simple_pid_list
*new_pid
= xmalloc (sizeof (struct simple_pid_list
));
292 new_pid
->status
= status
;
293 new_pid
->next
= *listp
;
298 in_pid_list_p (struct simple_pid_list
*list
, int pid
)
300 struct simple_pid_list
*p
;
302 for (p
= list
; p
!= NULL
; p
= p
->next
)
309 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
311 struct simple_pid_list
**p
;
313 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
314 if ((*p
)->pid
== pid
)
316 struct simple_pid_list
*next
= (*p
)->next
;
318 *statusp
= (*p
)->status
;
326 /* Initialize ptrace warnings and check for supported ptrace
327 features given PID. */
330 linux_init_ptrace (pid_t pid
)
332 linux_enable_event_reporting (pid
);
333 linux_ptrace_init_warnings ();
337 linux_child_post_attach (struct target_ops
*self
, int pid
)
339 linux_init_ptrace (pid
);
343 linux_child_post_startup_inferior (struct target_ops
*self
, ptid_t ptid
)
345 linux_init_ptrace (ptid_get_pid (ptid
));
348 /* Return the number of known LWPs in the tgid given by PID. */
356 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
357 if (ptid_get_pid (lp
->ptid
) == pid
)
363 /* Call delete_lwp with prototype compatible for make_cleanup. */
366 delete_lwp_cleanup (void *lp_voidp
)
368 struct lwp_info
*lp
= lp_voidp
;
370 delete_lwp (lp
->ptid
);
374 linux_child_follow_fork (struct target_ops
*ops
, int follow_child
,
378 int parent_pid
, child_pid
;
380 has_vforked
= (inferior_thread ()->pending_follow
.kind
381 == TARGET_WAITKIND_VFORKED
);
382 parent_pid
= ptid_get_lwp (inferior_ptid
);
384 parent_pid
= ptid_get_pid (inferior_ptid
);
386 = ptid_get_pid (inferior_thread ()->pending_follow
.value
.related_pid
);
389 && !non_stop
/* Non-stop always resumes both branches. */
390 && (!target_is_async_p () || sync_execution
)
391 && !(follow_child
|| detach_fork
|| sched_multi
))
393 /* The parent stays blocked inside the vfork syscall until the
394 child execs or exits. If we don't let the child run, then
395 the parent stays blocked. If we're telling the parent to run
396 in the foreground, the user will not be able to ctrl-c to get
397 back the terminal, effectively hanging the debug session. */
398 fprintf_filtered (gdb_stderr
, _("\
399 Can not resume the parent process over vfork in the foreground while\n\
400 holding the child stopped. Try \"set detach-on-fork\" or \
401 \"set schedule-multiple\".\n"));
402 /* FIXME output string > 80 columns. */
408 struct lwp_info
*child_lp
= NULL
;
410 /* We're already attached to the parent, by default. */
412 /* Detach new forked process? */
415 struct cleanup
*old_chain
;
416 int status
= W_STOPCODE (0);
418 /* Before detaching from the child, remove all breakpoints
419 from it. If we forked, then this has already been taken
420 care of by infrun.c. If we vforked however, any
421 breakpoint inserted in the parent is visible in the
422 child, even those added while stopped in a vfork
423 catchpoint. This will remove the breakpoints from the
424 parent also, but they'll be reinserted below. */
427 /* keep breakpoints list in sync. */
428 remove_breakpoints_pid (ptid_get_pid (inferior_ptid
));
431 if (info_verbose
|| debug_linux_nat
)
433 target_terminal_ours ();
434 fprintf_filtered (gdb_stdlog
,
435 "Detaching after fork from "
436 "child process %d.\n",
440 old_chain
= save_inferior_ptid ();
441 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
443 child_lp
= add_lwp (inferior_ptid
);
444 child_lp
->stopped
= 1;
445 child_lp
->last_resume_kind
= resume_stop
;
446 make_cleanup (delete_lwp_cleanup
, child_lp
);
448 if (linux_nat_prepare_to_resume
!= NULL
)
449 linux_nat_prepare_to_resume (child_lp
);
451 /* When debugging an inferior in an architecture that supports
452 hardware single stepping on a kernel without commit
453 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
454 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
455 set if the parent process had them set.
456 To work around this, single step the child process
457 once before detaching to clear the flags. */
459 if (!gdbarch_software_single_step_p (target_thread_architecture
462 linux_disable_event_reporting (child_pid
);
463 if (ptrace (PTRACE_SINGLESTEP
, child_pid
, 0, 0) < 0)
464 perror_with_name (_("Couldn't do single step"));
465 if (my_waitpid (child_pid
, &status
, 0) < 0)
466 perror_with_name (_("Couldn't wait vfork process"));
469 if (WIFSTOPPED (status
))
473 signo
= WSTOPSIG (status
);
475 && !signal_pass_state (gdb_signal_from_host (signo
)))
477 ptrace (PTRACE_DETACH
, child_pid
, 0, signo
);
480 do_cleanups (old_chain
);
484 struct inferior
*parent_inf
, *child_inf
;
485 struct cleanup
*old_chain
;
487 /* Add process to GDB's tables. */
488 child_inf
= add_inferior (child_pid
);
490 parent_inf
= current_inferior ();
491 child_inf
->attach_flag
= parent_inf
->attach_flag
;
492 copy_terminal_info (child_inf
, parent_inf
);
493 child_inf
->gdbarch
= parent_inf
->gdbarch
;
494 copy_inferior_target_desc_info (child_inf
, parent_inf
);
496 old_chain
= save_inferior_ptid ();
497 save_current_program_space ();
499 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
500 add_thread (inferior_ptid
);
501 child_lp
= add_lwp (inferior_ptid
);
502 child_lp
->stopped
= 1;
503 child_lp
->last_resume_kind
= resume_stop
;
504 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
506 /* If this is a vfork child, then the address-space is
507 shared with the parent. */
510 child_inf
->pspace
= parent_inf
->pspace
;
511 child_inf
->aspace
= parent_inf
->aspace
;
513 /* The parent will be frozen until the child is done
514 with the shared region. Keep track of the
516 child_inf
->vfork_parent
= parent_inf
;
517 child_inf
->pending_detach
= 0;
518 parent_inf
->vfork_child
= child_inf
;
519 parent_inf
->pending_detach
= 0;
523 child_inf
->aspace
= new_address_space ();
524 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
525 child_inf
->removable
= 1;
526 set_current_program_space (child_inf
->pspace
);
527 clone_program_space (child_inf
->pspace
, parent_inf
->pspace
);
529 /* Let the shared library layer (solib-svr4) learn about
530 this new process, relocate the cloned exec, pull in
531 shared libraries, and install the solib event
532 breakpoint. If a "cloned-VM" event was propagated
533 better throughout the core, this wouldn't be
535 solib_create_inferior_hook (0);
538 /* Let the thread_db layer learn about this new process. */
539 check_for_thread_db ();
541 do_cleanups (old_chain
);
546 struct lwp_info
*parent_lp
;
547 struct inferior
*parent_inf
;
549 parent_inf
= current_inferior ();
551 /* If we detached from the child, then we have to be careful
552 to not insert breakpoints in the parent until the child
553 is done with the shared memory region. However, if we're
554 staying attached to the child, then we can and should
555 insert breakpoints, so that we can debug it. A
556 subsequent child exec or exit is enough to know when does
557 the child stops using the parent's address space. */
558 parent_inf
->waiting_for_vfork_done
= detach_fork
;
559 parent_inf
->pspace
->breakpoints_not_allowed
= detach_fork
;
561 parent_lp
= find_lwp_pid (pid_to_ptid (parent_pid
));
562 gdb_assert (linux_supports_tracefork () >= 0);
564 if (linux_supports_tracevforkdone ())
567 fprintf_unfiltered (gdb_stdlog
,
568 "LCFF: waiting for VFORK_DONE on %d\n",
570 parent_lp
->stopped
= 1;
572 /* We'll handle the VFORK_DONE event like any other
573 event, in target_wait. */
577 /* We can't insert breakpoints until the child has
578 finished with the shared memory region. We need to
579 wait until that happens. Ideal would be to just
581 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
582 - waitpid (parent_pid, &status, __WALL);
583 However, most architectures can't handle a syscall
584 being traced on the way out if it wasn't traced on
587 We might also think to loop, continuing the child
588 until it exits or gets a SIGTRAP. One problem is
589 that the child might call ptrace with PTRACE_TRACEME.
591 There's no simple and reliable way to figure out when
592 the vforked child will be done with its copy of the
593 shared memory. We could step it out of the syscall,
594 two instructions, let it go, and then single-step the
595 parent once. When we have hardware single-step, this
596 would work; with software single-step it could still
597 be made to work but we'd have to be able to insert
598 single-step breakpoints in the child, and we'd have
599 to insert -just- the single-step breakpoint in the
600 parent. Very awkward.
602 In the end, the best we can do is to make sure it
603 runs for a little while. Hopefully it will be out of
604 range of any breakpoints we reinsert. Usually this
605 is only the single-step breakpoint at vfork's return
609 fprintf_unfiltered (gdb_stdlog
,
610 "LCFF: no VFORK_DONE "
611 "support, sleeping a bit\n");
615 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
616 and leave it pending. The next linux_nat_resume call
617 will notice a pending event, and bypasses actually
618 resuming the inferior. */
619 parent_lp
->status
= 0;
620 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
621 parent_lp
->stopped
= 1;
623 /* If we're in async mode, need to tell the event loop
624 there's something here to process. */
625 if (target_can_async_p ())
632 struct inferior
*parent_inf
, *child_inf
;
633 struct lwp_info
*child_lp
;
634 struct program_space
*parent_pspace
;
636 if (info_verbose
|| debug_linux_nat
)
638 target_terminal_ours ();
640 fprintf_filtered (gdb_stdlog
,
641 _("Attaching after process %d "
642 "vfork to child process %d.\n"),
643 parent_pid
, child_pid
);
645 fprintf_filtered (gdb_stdlog
,
646 _("Attaching after process %d "
647 "fork to child process %d.\n"),
648 parent_pid
, child_pid
);
651 /* Add the new inferior first, so that the target_detach below
652 doesn't unpush the target. */
654 child_inf
= add_inferior (child_pid
);
656 parent_inf
= current_inferior ();
657 child_inf
->attach_flag
= parent_inf
->attach_flag
;
658 copy_terminal_info (child_inf
, parent_inf
);
659 child_inf
->gdbarch
= parent_inf
->gdbarch
;
660 copy_inferior_target_desc_info (child_inf
, parent_inf
);
662 parent_pspace
= parent_inf
->pspace
;
664 /* If we're vforking, we want to hold on to the parent until the
665 child exits or execs. At child exec or exit time we can
666 remove the old breakpoints from the parent and detach or
667 resume debugging it. Otherwise, detach the parent now; we'll
668 want to reuse it's program/address spaces, but we can't set
669 them to the child before removing breakpoints from the
670 parent, otherwise, the breakpoints module could decide to
671 remove breakpoints from the wrong process (since they'd be
672 assigned to the same address space). */
676 gdb_assert (child_inf
->vfork_parent
== NULL
);
677 gdb_assert (parent_inf
->vfork_child
== NULL
);
678 child_inf
->vfork_parent
= parent_inf
;
679 child_inf
->pending_detach
= 0;
680 parent_inf
->vfork_child
= child_inf
;
681 parent_inf
->pending_detach
= detach_fork
;
682 parent_inf
->waiting_for_vfork_done
= 0;
684 else if (detach_fork
)
685 target_detach (NULL
, 0);
687 /* Note that the detach above makes PARENT_INF dangling. */
689 /* Add the child thread to the appropriate lists, and switch to
690 this new thread, before cloning the program space, and
691 informing the solib layer about this new process. */
693 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
694 add_thread (inferior_ptid
);
695 child_lp
= add_lwp (inferior_ptid
);
696 child_lp
->stopped
= 1;
697 child_lp
->last_resume_kind
= resume_stop
;
699 /* If this is a vfork child, then the address-space is shared
700 with the parent. If we detached from the parent, then we can
701 reuse the parent's program/address spaces. */
702 if (has_vforked
|| detach_fork
)
704 child_inf
->pspace
= parent_pspace
;
705 child_inf
->aspace
= child_inf
->pspace
->aspace
;
709 child_inf
->aspace
= new_address_space ();
710 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
711 child_inf
->removable
= 1;
712 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
713 set_current_program_space (child_inf
->pspace
);
714 clone_program_space (child_inf
->pspace
, parent_pspace
);
716 /* Let the shared library layer (solib-svr4) learn about
717 this new process, relocate the cloned exec, pull in
718 shared libraries, and install the solib event breakpoint.
719 If a "cloned-VM" event was propagated better throughout
720 the core, this wouldn't be required. */
721 solib_create_inferior_hook (0);
724 /* Let the thread_db layer learn about this new process. */
725 check_for_thread_db ();
733 linux_child_insert_fork_catchpoint (struct target_ops
*self
, int pid
)
735 return !linux_supports_tracefork ();
739 linux_child_remove_fork_catchpoint (struct target_ops
*self
, int pid
)
745 linux_child_insert_vfork_catchpoint (struct target_ops
*self
, int pid
)
747 return !linux_supports_tracefork ();
751 linux_child_remove_vfork_catchpoint (struct target_ops
*self
, int pid
)
757 linux_child_insert_exec_catchpoint (struct target_ops
*self
, int pid
)
759 return !linux_supports_tracefork ();
763 linux_child_remove_exec_catchpoint (struct target_ops
*self
, int pid
)
769 linux_child_set_syscall_catchpoint (struct target_ops
*self
,
770 int pid
, int needed
, int any_count
,
771 int table_size
, int *table
)
773 if (!linux_supports_tracesysgood ())
776 /* On GNU/Linux, we ignore the arguments. It means that we only
777 enable the syscall catchpoints, but do not disable them.
779 Also, we do not use the `table' information because we do not
780 filter system calls here. We let GDB do the logic for us. */
784 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
785 are processes sharing the same VM space. A multi-threaded process
786 is basically a group of such processes. However, such a grouping
787 is almost entirely a user-space issue; the kernel doesn't enforce
788 such a grouping at all (this might change in the future). In
789 general, we'll rely on the threads library (i.e. the GNU/Linux
790 Threads library) to provide such a grouping.
792 It is perfectly well possible to write a multi-threaded application
793 without the assistance of a threads library, by using the clone
794 system call directly. This module should be able to give some
795 rudimentary support for debugging such applications if developers
796 specify the CLONE_PTRACE flag in the clone system call, and are
797 using the Linux kernel 2.4 or above.
799 Note that there are some peculiarities in GNU/Linux that affect
802 - In general one should specify the __WCLONE flag to waitpid in
803 order to make it report events for any of the cloned processes
804 (and leave it out for the initial process). However, if a cloned
805 process has exited the exit status is only reported if the
806 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
807 we cannot use it since GDB must work on older systems too.
809 - When a traced, cloned process exits and is waited for by the
810 debugger, the kernel reassigns it to the original parent and
811 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
812 library doesn't notice this, which leads to the "zombie problem":
813 When debugged a multi-threaded process that spawns a lot of
814 threads will run out of processes, even if the threads exit,
815 because the "zombies" stay around. */
817 /* List of known LWPs. */
818 struct lwp_info
*lwp_list
;
821 /* Original signal mask. */
822 static sigset_t normal_mask
;
824 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
825 _initialize_linux_nat. */
826 static sigset_t suspend_mask
;
828 /* Signals to block to make that sigsuspend work. */
829 static sigset_t blocked_mask
;
831 /* SIGCHLD action. */
832 struct sigaction sigchld_action
;
834 /* Block child signals (SIGCHLD and linux threads signals), and store
835 the previous mask in PREV_MASK. */
838 block_child_signals (sigset_t
*prev_mask
)
840 /* Make sure SIGCHLD is blocked. */
841 if (!sigismember (&blocked_mask
, SIGCHLD
))
842 sigaddset (&blocked_mask
, SIGCHLD
);
844 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
847 /* Restore child signals mask, previously returned by
848 block_child_signals. */
851 restore_child_signals_mask (sigset_t
*prev_mask
)
853 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
856 /* Mask of signals to pass directly to the inferior. */
857 static sigset_t pass_mask
;
859 /* Update signals to pass to the inferior. */
861 linux_nat_pass_signals (struct target_ops
*self
,
862 int numsigs
, unsigned char *pass_signals
)
866 sigemptyset (&pass_mask
);
868 for (signo
= 1; signo
< NSIG
; signo
++)
870 int target_signo
= gdb_signal_from_host (signo
);
871 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
872 sigaddset (&pass_mask
, signo
);
878 /* Prototypes for local functions. */
879 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
880 static int linux_thread_alive (ptid_t ptid
);
881 static char *linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
);
885 /* Destroy and free LP. */
888 lwp_free (struct lwp_info
*lp
)
890 xfree (lp
->arch_private
);
894 /* Remove all LWPs belong to PID from the lwp list. */
897 purge_lwp_list (int pid
)
899 struct lwp_info
*lp
, *lpprev
, *lpnext
;
903 for (lp
= lwp_list
; lp
; lp
= lpnext
)
907 if (ptid_get_pid (lp
->ptid
) == pid
)
912 lpprev
->next
= lp
->next
;
921 /* Add the LWP specified by PTID to the list. PTID is the first LWP
922 in the process. Return a pointer to the structure describing the
925 This differs from add_lwp in that we don't let the arch specific
926 bits know about this new thread. Current clients of this callback
927 take the opportunity to install watchpoints in the new thread, and
928 we shouldn't do that for the first thread. If we're spawning a
929 child ("run"), the thread executes the shell wrapper first, and we
930 shouldn't touch it until it execs the program we want to debug.
931 For "attach", it'd be okay to call the callback, but it's not
932 necessary, because watchpoints can't yet have been inserted into
935 static struct lwp_info
*
936 add_initial_lwp (ptid_t ptid
)
940 gdb_assert (ptid_lwp_p (ptid
));
942 lp
= (struct lwp_info
*) xmalloc (sizeof (struct lwp_info
));
944 memset (lp
, 0, sizeof (struct lwp_info
));
946 lp
->last_resume_kind
= resume_continue
;
947 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
958 /* Add the LWP specified by PID to the list. Return a pointer to the
959 structure describing the new LWP. The LWP should already be
962 static struct lwp_info
*
963 add_lwp (ptid_t ptid
)
967 lp
= add_initial_lwp (ptid
);
969 /* Let the arch specific bits know about this new thread. Current
970 clients of this callback take the opportunity to install
971 watchpoints in the new thread. We don't do this for the first
972 thread though. See add_initial_lwp. */
973 if (linux_nat_new_thread
!= NULL
)
974 linux_nat_new_thread (lp
);
979 /* Remove the LWP specified by PID from the list. */
982 delete_lwp (ptid_t ptid
)
984 struct lwp_info
*lp
, *lpprev
;
988 for (lp
= lwp_list
; lp
; lpprev
= lp
, lp
= lp
->next
)
989 if (ptid_equal (lp
->ptid
, ptid
))
996 lpprev
->next
= lp
->next
;
1003 /* Return a pointer to the structure describing the LWP corresponding
1004 to PID. If no corresponding LWP could be found, return NULL. */
1006 static struct lwp_info
*
1007 find_lwp_pid (ptid_t ptid
)
1009 struct lwp_info
*lp
;
1012 if (ptid_lwp_p (ptid
))
1013 lwp
= ptid_get_lwp (ptid
);
1015 lwp
= ptid_get_pid (ptid
);
1017 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
1018 if (lwp
== ptid_get_lwp (lp
->ptid
))
1024 /* Call CALLBACK with its second argument set to DATA for every LWP in
1025 the list. If CALLBACK returns 1 for a particular LWP, return a
1026 pointer to the structure describing that LWP immediately.
1027 Otherwise return NULL. */
1030 iterate_over_lwps (ptid_t filter
,
1031 int (*callback
) (struct lwp_info
*, void *),
1034 struct lwp_info
*lp
, *lpnext
;
1036 for (lp
= lwp_list
; lp
; lp
= lpnext
)
1040 if (ptid_match (lp
->ptid
, filter
))
1042 if ((*callback
) (lp
, data
))
1050 /* Update our internal state when changing from one checkpoint to
1051 another indicated by NEW_PTID. We can only switch single-threaded
1052 applications, so we only create one new LWP, and the previous list
1056 linux_nat_switch_fork (ptid_t new_ptid
)
1058 struct lwp_info
*lp
;
1060 purge_lwp_list (ptid_get_pid (inferior_ptid
));
1062 lp
= add_lwp (new_ptid
);
1065 /* This changes the thread's ptid while preserving the gdb thread
1066 num. Also changes the inferior pid, while preserving the
1068 thread_change_ptid (inferior_ptid
, new_ptid
);
1070 /* We've just told GDB core that the thread changed target id, but,
1071 in fact, it really is a different thread, with different register
1073 registers_changed ();
1076 /* Handle the exit of a single thread LP. */
1079 exit_lwp (struct lwp_info
*lp
)
1081 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1085 if (print_thread_events
)
1086 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
1088 delete_thread (lp
->ptid
);
1091 delete_lwp (lp
->ptid
);
1094 /* Wait for the LWP specified by LP, which we have just attached to.
1095 Returns a wait status for that LWP, to cache. */
1098 linux_nat_post_attach_wait (ptid_t ptid
, int first
, int *cloned
,
1101 pid_t new_pid
, pid
= ptid_get_lwp (ptid
);
1104 if (linux_proc_pid_is_stopped (pid
))
1106 if (debug_linux_nat
)
1107 fprintf_unfiltered (gdb_stdlog
,
1108 "LNPAW: Attaching to a stopped process\n");
1110 /* The process is definitely stopped. It is in a job control
1111 stop, unless the kernel predates the TASK_STOPPED /
1112 TASK_TRACED distinction, in which case it might be in a
1113 ptrace stop. Make sure it is in a ptrace stop; from there we
1114 can kill it, signal it, et cetera.
1116 First make sure there is a pending SIGSTOP. Since we are
1117 already attached, the process can not transition from stopped
1118 to running without a PTRACE_CONT; so we know this signal will
1119 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1120 probably already in the queue (unless this kernel is old
1121 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1122 is not an RT signal, it can only be queued once. */
1123 kill_lwp (pid
, SIGSTOP
);
1125 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1126 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1127 ptrace (PTRACE_CONT
, pid
, 0, 0);
1130 /* Make sure the initial process is stopped. The user-level threads
1131 layer might want to poke around in the inferior, and that won't
1132 work if things haven't stabilized yet. */
1133 new_pid
= my_waitpid (pid
, &status
, 0);
1134 if (new_pid
== -1 && errno
== ECHILD
)
1137 warning (_("%s is a cloned process"), target_pid_to_str (ptid
));
1139 /* Try again with __WCLONE to check cloned processes. */
1140 new_pid
= my_waitpid (pid
, &status
, __WCLONE
);
1144 gdb_assert (pid
== new_pid
);
1146 if (!WIFSTOPPED (status
))
1148 /* The pid we tried to attach has apparently just exited. */
1149 if (debug_linux_nat
)
1150 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1151 pid
, status_to_str (status
));
1155 if (WSTOPSIG (status
) != SIGSTOP
)
1158 if (debug_linux_nat
)
1159 fprintf_unfiltered (gdb_stdlog
,
1160 "LNPAW: Received %s after attaching\n",
1161 status_to_str (status
));
1167 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1168 the new LWP could not be attached, or 1 if we're already auto
1169 attached to this thread, but haven't processed the
1170 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1171 its existance, without considering it an error. */
1174 lin_lwp_attach_lwp (ptid_t ptid
)
1176 struct lwp_info
*lp
;
1179 gdb_assert (ptid_lwp_p (ptid
));
1181 lp
= find_lwp_pid (ptid
);
1182 lwpid
= ptid_get_lwp (ptid
);
1184 /* We assume that we're already attached to any LWP that has an id
1185 equal to the overall process id, and to any LWP that is already
1186 in our list of LWPs. If we're not seeing exit events from threads
1187 and we've had PID wraparound since we last tried to stop all threads,
1188 this assumption might be wrong; fortunately, this is very unlikely
1190 if (lwpid
!= ptid_get_pid (ptid
) && lp
== NULL
)
1192 int status
, cloned
= 0, signalled
= 0;
1194 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1196 if (linux_supports_tracefork ())
1198 /* If we haven't stopped all threads when we get here,
1199 we may have seen a thread listed in thread_db's list,
1200 but not processed the PTRACE_EVENT_CLONE yet. If
1201 that's the case, ignore this new thread, and let
1202 normal event handling discover it later. */
1203 if (in_pid_list_p (stopped_pids
, lwpid
))
1205 /* We've already seen this thread stop, but we
1206 haven't seen the PTRACE_EVENT_CLONE extended
1215 /* See if we've got a stop for this new child
1216 pending. If so, we're already attached. */
1217 new_pid
= my_waitpid (lwpid
, &status
, WNOHANG
);
1218 if (new_pid
== -1 && errno
== ECHILD
)
1219 new_pid
= my_waitpid (lwpid
, &status
, __WCLONE
| WNOHANG
);
1222 if (WIFSTOPPED (status
))
1223 add_to_pid_list (&stopped_pids
, lwpid
, status
);
1229 /* If we fail to attach to the thread, issue a warning,
1230 but continue. One way this can happen is if thread
1231 creation is interrupted; as of Linux kernel 2.6.19, a
1232 bug may place threads in the thread list and then fail
1234 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid
),
1235 safe_strerror (errno
));
1239 if (debug_linux_nat
)
1240 fprintf_unfiltered (gdb_stdlog
,
1241 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1242 target_pid_to_str (ptid
));
1244 status
= linux_nat_post_attach_wait (ptid
, 0, &cloned
, &signalled
);
1245 if (!WIFSTOPPED (status
))
1248 lp
= add_lwp (ptid
);
1250 lp
->cloned
= cloned
;
1251 lp
->signalled
= signalled
;
1252 if (WSTOPSIG (status
) != SIGSTOP
)
1255 lp
->status
= status
;
1258 target_post_attach (ptid_get_lwp (lp
->ptid
));
1260 if (debug_linux_nat
)
1262 fprintf_unfiltered (gdb_stdlog
,
1263 "LLAL: waitpid %s received %s\n",
1264 target_pid_to_str (ptid
),
1265 status_to_str (status
));
1270 /* We assume that the LWP representing the original process is
1271 already stopped. Mark it as stopped in the data structure
1272 that the GNU/linux ptrace layer uses to keep track of
1273 threads. Note that this won't have already been done since
1274 the main thread will have, we assume, been stopped by an
1275 attach from a different layer. */
1277 lp
= add_lwp (ptid
);
1281 lp
->last_resume_kind
= resume_stop
;
1286 linux_nat_create_inferior (struct target_ops
*ops
,
1287 char *exec_file
, char *allargs
, char **env
,
1290 #ifdef HAVE_PERSONALITY
1291 int personality_orig
= 0, personality_set
= 0;
1292 #endif /* HAVE_PERSONALITY */
1294 /* The fork_child mechanism is synchronous and calls target_wait, so
1295 we have to mask the async mode. */
1297 #ifdef HAVE_PERSONALITY
1298 if (disable_randomization
)
1301 personality_orig
= personality (0xffffffff);
1302 if (errno
== 0 && !(personality_orig
& ADDR_NO_RANDOMIZE
))
1304 personality_set
= 1;
1305 personality (personality_orig
| ADDR_NO_RANDOMIZE
);
1307 if (errno
!= 0 || (personality_set
1308 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE
)))
1309 warning (_("Error disabling address space randomization: %s"),
1310 safe_strerror (errno
));
1312 #endif /* HAVE_PERSONALITY */
1314 /* Make sure we report all signals during startup. */
1315 linux_nat_pass_signals (ops
, 0, NULL
);
1317 linux_ops
->to_create_inferior (ops
, exec_file
, allargs
, env
, from_tty
);
1319 #ifdef HAVE_PERSONALITY
1320 if (personality_set
)
1323 personality (personality_orig
);
1325 warning (_("Error restoring address space randomization: %s"),
1326 safe_strerror (errno
));
1328 #endif /* HAVE_PERSONALITY */
1332 linux_nat_attach (struct target_ops
*ops
, const char *args
, int from_tty
)
1334 struct lwp_info
*lp
;
1337 volatile struct gdb_exception ex
;
1339 /* Make sure we report all signals during attach. */
1340 linux_nat_pass_signals (ops
, 0, NULL
);
1342 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
1344 linux_ops
->to_attach (ops
, args
, from_tty
);
1348 pid_t pid
= parse_pid_to_attach (args
);
1349 struct buffer buffer
;
1350 char *message
, *buffer_s
;
1352 message
= xstrdup (ex
.message
);
1353 make_cleanup (xfree
, message
);
1355 buffer_init (&buffer
);
1356 linux_ptrace_attach_fail_reason (pid
, &buffer
);
1358 buffer_grow_str0 (&buffer
, "");
1359 buffer_s
= buffer_finish (&buffer
);
1360 make_cleanup (xfree
, buffer_s
);
1362 if (*buffer_s
!= '\0')
1363 throw_error (ex
.error
, "warning: %s\n%s", buffer_s
, message
);
1365 throw_error (ex
.error
, "%s", message
);
1368 /* The ptrace base target adds the main thread with (pid,0,0)
1369 format. Decorate it with lwp info. */
1370 ptid
= ptid_build (ptid_get_pid (inferior_ptid
),
1371 ptid_get_pid (inferior_ptid
),
1373 thread_change_ptid (inferior_ptid
, ptid
);
1375 /* Add the initial process as the first LWP to the list. */
1376 lp
= add_initial_lwp (ptid
);
1378 status
= linux_nat_post_attach_wait (lp
->ptid
, 1, &lp
->cloned
,
1380 if (!WIFSTOPPED (status
))
1382 if (WIFEXITED (status
))
1384 int exit_code
= WEXITSTATUS (status
);
1386 target_terminal_ours ();
1387 target_mourn_inferior ();
1389 error (_("Unable to attach: program exited normally."));
1391 error (_("Unable to attach: program exited with code %d."),
1394 else if (WIFSIGNALED (status
))
1396 enum gdb_signal signo
;
1398 target_terminal_ours ();
1399 target_mourn_inferior ();
1401 signo
= gdb_signal_from_host (WTERMSIG (status
));
1402 error (_("Unable to attach: program terminated with signal "
1404 gdb_signal_to_name (signo
),
1405 gdb_signal_to_string (signo
));
1408 internal_error (__FILE__
, __LINE__
,
1409 _("unexpected status %d for PID %ld"),
1410 status
, (long) ptid_get_lwp (ptid
));
1415 /* Save the wait status to report later. */
1417 if (debug_linux_nat
)
1418 fprintf_unfiltered (gdb_stdlog
,
1419 "LNA: waitpid %ld, saving status %s\n",
1420 (long) ptid_get_pid (lp
->ptid
), status_to_str (status
));
1422 lp
->status
= status
;
1424 if (target_can_async_p ())
1425 target_async (inferior_event_handler
, 0);
1428 /* Get pending status of LP. */
1430 get_pending_status (struct lwp_info
*lp
, int *status
)
1432 enum gdb_signal signo
= GDB_SIGNAL_0
;
1434 /* If we paused threads momentarily, we may have stored pending
1435 events in lp->status or lp->waitstatus (see stop_wait_callback),
1436 and GDB core hasn't seen any signal for those threads.
1437 Otherwise, the last signal reported to the core is found in the
1438 thread object's stop_signal.
1440 There's a corner case that isn't handled here at present. Only
1441 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1442 stop_signal make sense as a real signal to pass to the inferior.
1443 Some catchpoint related events, like
1444 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1445 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1446 those traps are debug API (ptrace in our case) related and
1447 induced; the inferior wouldn't see them if it wasn't being
1448 traced. Hence, we should never pass them to the inferior, even
1449 when set to pass state. Since this corner case isn't handled by
1450 infrun.c when proceeding with a signal, for consistency, neither
1451 do we handle it here (or elsewhere in the file we check for
1452 signal pass state). Normally SIGTRAP isn't set to pass state, so
1453 this is really a corner case. */
1455 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1456 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1457 else if (lp
->status
)
1458 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1459 else if (non_stop
&& !is_executing (lp
->ptid
))
1461 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1463 signo
= tp
->suspend
.stop_signal
;
1467 struct target_waitstatus last
;
1470 get_last_target_status (&last_ptid
, &last
);
1472 if (ptid_get_lwp (lp
->ptid
) == ptid_get_lwp (last_ptid
))
1474 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1476 signo
= tp
->suspend
.stop_signal
;
1482 if (signo
== GDB_SIGNAL_0
)
1484 if (debug_linux_nat
)
1485 fprintf_unfiltered (gdb_stdlog
,
1486 "GPT: lwp %s has no pending signal\n",
1487 target_pid_to_str (lp
->ptid
));
1489 else if (!signal_pass_state (signo
))
1491 if (debug_linux_nat
)
1492 fprintf_unfiltered (gdb_stdlog
,
1493 "GPT: lwp %s had signal %s, "
1494 "but it is in no pass state\n",
1495 target_pid_to_str (lp
->ptid
),
1496 gdb_signal_to_string (signo
));
1500 *status
= W_STOPCODE (gdb_signal_to_host (signo
));
1502 if (debug_linux_nat
)
1503 fprintf_unfiltered (gdb_stdlog
,
1504 "GPT: lwp %s has pending signal %s\n",
1505 target_pid_to_str (lp
->ptid
),
1506 gdb_signal_to_string (signo
));
1513 detach_callback (struct lwp_info
*lp
, void *data
)
1515 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1517 if (debug_linux_nat
&& lp
->status
)
1518 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1519 strsignal (WSTOPSIG (lp
->status
)),
1520 target_pid_to_str (lp
->ptid
));
1522 /* If there is a pending SIGSTOP, get rid of it. */
1525 if (debug_linux_nat
)
1526 fprintf_unfiltered (gdb_stdlog
,
1527 "DC: Sending SIGCONT to %s\n",
1528 target_pid_to_str (lp
->ptid
));
1530 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGCONT
);
1534 /* We don't actually detach from the LWP that has an id equal to the
1535 overall process id just yet. */
1536 if (ptid_get_lwp (lp
->ptid
) != ptid_get_pid (lp
->ptid
))
1540 /* Pass on any pending signal for this LWP. */
1541 get_pending_status (lp
, &status
);
1543 if (linux_nat_prepare_to_resume
!= NULL
)
1544 linux_nat_prepare_to_resume (lp
);
1546 if (ptrace (PTRACE_DETACH
, ptid_get_lwp (lp
->ptid
), 0,
1547 WSTOPSIG (status
)) < 0)
1548 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1549 safe_strerror (errno
));
1551 if (debug_linux_nat
)
1552 fprintf_unfiltered (gdb_stdlog
,
1553 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1554 target_pid_to_str (lp
->ptid
),
1555 strsignal (WSTOPSIG (status
)));
1557 delete_lwp (lp
->ptid
);
1564 linux_nat_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1568 struct lwp_info
*main_lwp
;
1570 pid
= ptid_get_pid (inferior_ptid
);
1572 /* Don't unregister from the event loop, as there may be other
1573 inferiors running. */
1575 /* Stop all threads before detaching. ptrace requires that the
1576 thread is stopped to sucessfully detach. */
1577 iterate_over_lwps (pid_to_ptid (pid
), stop_callback
, NULL
);
1578 /* ... and wait until all of them have reported back that
1579 they're no longer running. */
1580 iterate_over_lwps (pid_to_ptid (pid
), stop_wait_callback
, NULL
);
1582 iterate_over_lwps (pid_to_ptid (pid
), detach_callback
, NULL
);
1584 /* Only the initial process should be left right now. */
1585 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid
)) == 1);
1587 main_lwp
= find_lwp_pid (pid_to_ptid (pid
));
1589 /* Pass on any pending signal for the last LWP. */
1590 if ((args
== NULL
|| *args
== '\0')
1591 && get_pending_status (main_lwp
, &status
) != -1
1592 && WIFSTOPPED (status
))
1596 /* Put the signal number in ARGS so that inf_ptrace_detach will
1597 pass it along with PTRACE_DETACH. */
1599 xsnprintf (tem
, 8, "%d", (int) WSTOPSIG (status
));
1601 if (debug_linux_nat
)
1602 fprintf_unfiltered (gdb_stdlog
,
1603 "LND: Sending signal %s to %s\n",
1605 target_pid_to_str (main_lwp
->ptid
));
1608 if (linux_nat_prepare_to_resume
!= NULL
)
1609 linux_nat_prepare_to_resume (main_lwp
);
1610 delete_lwp (main_lwp
->ptid
);
1612 if (forks_exist_p ())
1614 /* Multi-fork case. The current inferior_ptid is being detached
1615 from, but there are other viable forks to debug. Detach from
1616 the current fork, and context-switch to the first
1618 linux_fork_detach (args
, from_tty
);
1621 linux_ops
->to_detach (ops
, args
, from_tty
);
1627 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1631 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
1633 if (inf
->vfork_child
!= NULL
)
1635 if (debug_linux_nat
)
1636 fprintf_unfiltered (gdb_stdlog
,
1637 "RC: Not resuming %s (vfork parent)\n",
1638 target_pid_to_str (lp
->ptid
));
1640 else if (lp
->status
== 0
1641 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
1643 if (debug_linux_nat
)
1644 fprintf_unfiltered (gdb_stdlog
,
1645 "RC: Resuming sibling %s, %s, %s\n",
1646 target_pid_to_str (lp
->ptid
),
1647 (signo
!= GDB_SIGNAL_0
1648 ? strsignal (gdb_signal_to_host (signo
))
1650 step
? "step" : "resume");
1652 if (linux_nat_prepare_to_resume
!= NULL
)
1653 linux_nat_prepare_to_resume (lp
);
1654 linux_ops
->to_resume (linux_ops
,
1655 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
1659 lp
->stopped_by_watchpoint
= 0;
1663 if (debug_linux_nat
)
1664 fprintf_unfiltered (gdb_stdlog
,
1665 "RC: Not resuming sibling %s (has pending)\n",
1666 target_pid_to_str (lp
->ptid
));
1671 if (debug_linux_nat
)
1672 fprintf_unfiltered (gdb_stdlog
,
1673 "RC: Not resuming sibling %s (not stopped)\n",
1674 target_pid_to_str (lp
->ptid
));
1678 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1679 Resume LWP with the last stop signal, if it is in pass state. */
1682 linux_nat_resume_callback (struct lwp_info
*lp
, void *except
)
1684 enum gdb_signal signo
= GDB_SIGNAL_0
;
1691 struct thread_info
*thread
;
1693 thread
= find_thread_ptid (lp
->ptid
);
1696 signo
= thread
->suspend
.stop_signal
;
1697 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1701 resume_lwp (lp
, 0, signo
);
1706 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1709 lp
->last_resume_kind
= resume_stop
;
1714 resume_set_callback (struct lwp_info
*lp
, void *data
)
1717 lp
->last_resume_kind
= resume_continue
;
1722 linux_nat_resume (struct target_ops
*ops
,
1723 ptid_t ptid
, int step
, enum gdb_signal signo
)
1725 struct lwp_info
*lp
;
1728 if (debug_linux_nat
)
1729 fprintf_unfiltered (gdb_stdlog
,
1730 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1731 step
? "step" : "resume",
1732 target_pid_to_str (ptid
),
1733 (signo
!= GDB_SIGNAL_0
1734 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1735 target_pid_to_str (inferior_ptid
));
1737 /* A specific PTID means `step only this process id'. */
1738 resume_many
= (ptid_equal (minus_one_ptid
, ptid
)
1739 || ptid_is_pid (ptid
));
1741 /* Mark the lwps we're resuming as resumed. */
1742 iterate_over_lwps (ptid
, resume_set_callback
, NULL
);
1744 /* See if it's the current inferior that should be handled
1747 lp
= find_lwp_pid (inferior_ptid
);
1749 lp
= find_lwp_pid (ptid
);
1750 gdb_assert (lp
!= NULL
);
1752 /* Remember if we're stepping. */
1754 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1756 /* If we have a pending wait status for this thread, there is no
1757 point in resuming the process. But first make sure that
1758 linux_nat_wait won't preemptively handle the event - we
1759 should never take this short-circuit if we are going to
1760 leave LP running, since we have skipped resuming all the
1761 other threads. This bit of code needs to be synchronized
1762 with linux_nat_wait. */
1764 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1767 && WSTOPSIG (lp
->status
)
1768 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1770 if (debug_linux_nat
)
1771 fprintf_unfiltered (gdb_stdlog
,
1772 "LLR: Not short circuiting for ignored "
1773 "status 0x%x\n", lp
->status
);
1775 /* FIXME: What should we do if we are supposed to continue
1776 this thread with a signal? */
1777 gdb_assert (signo
== GDB_SIGNAL_0
);
1778 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1783 if (lp
->status
|| lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1785 /* FIXME: What should we do if we are supposed to continue
1786 this thread with a signal? */
1787 gdb_assert (signo
== GDB_SIGNAL_0
);
1789 if (debug_linux_nat
)
1790 fprintf_unfiltered (gdb_stdlog
,
1791 "LLR: Short circuiting for status 0x%x\n",
1794 if (target_can_async_p ())
1796 target_async (inferior_event_handler
, 0);
1797 /* Tell the event loop we have something to process. */
1804 iterate_over_lwps (ptid
, linux_nat_resume_callback
, lp
);
1806 /* Convert to something the lower layer understands. */
1807 ptid
= pid_to_ptid (ptid_get_lwp (lp
->ptid
));
1809 if (linux_nat_prepare_to_resume
!= NULL
)
1810 linux_nat_prepare_to_resume (lp
);
1811 linux_ops
->to_resume (linux_ops
, ptid
, step
, signo
);
1812 lp
->stopped_by_watchpoint
= 0;
1815 if (debug_linux_nat
)
1816 fprintf_unfiltered (gdb_stdlog
,
1817 "LLR: %s %s, %s (resume event thread)\n",
1818 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1819 target_pid_to_str (ptid
),
1820 (signo
!= GDB_SIGNAL_0
1821 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1823 if (target_can_async_p ())
1824 target_async (inferior_event_handler
, 0);
1827 /* Send a signal to an LWP. */
1830 kill_lwp (int lwpid
, int signo
)
1832 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1833 fails, then we are not using nptl threads and we should be using kill. */
1835 #ifdef HAVE_TKILL_SYSCALL
1837 static int tkill_failed
;
1844 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1845 if (errno
!= ENOSYS
)
1852 return kill (lwpid
, signo
);
1855 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1856 event, check if the core is interested in it: if not, ignore the
1857 event, and keep waiting; otherwise, we need to toggle the LWP's
1858 syscall entry/exit status, since the ptrace event itself doesn't
1859 indicate it, and report the trap to higher layers. */
1862 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1864 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1865 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1866 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, lp
->ptid
);
1870 /* If we're stopping threads, there's a SIGSTOP pending, which
1871 makes it so that the LWP reports an immediate syscall return,
1872 followed by the SIGSTOP. Skip seeing that "return" using
1873 PTRACE_CONT directly, and let stop_wait_callback collect the
1874 SIGSTOP. Later when the thread is resumed, a new syscall
1875 entry event. If we didn't do this (and returned 0), we'd
1876 leave a syscall entry pending, and our caller, by using
1877 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1878 itself. Later, when the user re-resumes this LWP, we'd see
1879 another syscall entry event and we'd mistake it for a return.
1881 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1882 (leaving immediately with LWP->signalled set, without issuing
1883 a PTRACE_CONT), it would still be problematic to leave this
1884 syscall enter pending, as later when the thread is resumed,
1885 it would then see the same syscall exit mentioned above,
1886 followed by the delayed SIGSTOP, while the syscall didn't
1887 actually get to execute. It seems it would be even more
1888 confusing to the user. */
1890 if (debug_linux_nat
)
1891 fprintf_unfiltered (gdb_stdlog
,
1892 "LHST: ignoring syscall %d "
1893 "for LWP %ld (stopping threads), "
1894 "resuming with PTRACE_CONT for SIGSTOP\n",
1896 ptid_get_lwp (lp
->ptid
));
1898 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1899 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
1904 if (catch_syscall_enabled ())
1906 /* Always update the entry/return state, even if this particular
1907 syscall isn't interesting to the core now. In async mode,
1908 the user could install a new catchpoint for this syscall
1909 between syscall enter/return, and we'll need to know to
1910 report a syscall return if that happens. */
1911 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1912 ? TARGET_WAITKIND_SYSCALL_RETURN
1913 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1915 if (catching_syscall_number (syscall_number
))
1917 /* Alright, an event to report. */
1918 ourstatus
->kind
= lp
->syscall_state
;
1919 ourstatus
->value
.syscall_number
= syscall_number
;
1921 if (debug_linux_nat
)
1922 fprintf_unfiltered (gdb_stdlog
,
1923 "LHST: stopping for %s of syscall %d"
1926 == TARGET_WAITKIND_SYSCALL_ENTRY
1927 ? "entry" : "return",
1929 ptid_get_lwp (lp
->ptid
));
1933 if (debug_linux_nat
)
1934 fprintf_unfiltered (gdb_stdlog
,
1935 "LHST: ignoring %s of syscall %d "
1937 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1938 ? "entry" : "return",
1940 ptid_get_lwp (lp
->ptid
));
1944 /* If we had been syscall tracing, and hence used PT_SYSCALL
1945 before on this LWP, it could happen that the user removes all
1946 syscall catchpoints before we get to process this event.
1947 There are two noteworthy issues here:
1949 - When stopped at a syscall entry event, resuming with
1950 PT_STEP still resumes executing the syscall and reports a
1953 - Only PT_SYSCALL catches syscall enters. If we last
1954 single-stepped this thread, then this event can't be a
1955 syscall enter. If we last single-stepped this thread, this
1956 has to be a syscall exit.
1958 The points above mean that the next resume, be it PT_STEP or
1959 PT_CONTINUE, can not trigger a syscall trace event. */
1960 if (debug_linux_nat
)
1961 fprintf_unfiltered (gdb_stdlog
,
1962 "LHST: caught syscall event "
1963 "with no syscall catchpoints."
1964 " %d for LWP %ld, ignoring\n",
1966 ptid_get_lwp (lp
->ptid
));
1967 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1970 /* The core isn't interested in this event. For efficiency, avoid
1971 stopping all threads only to have the core resume them all again.
1972 Since we're not stopping threads, if we're still syscall tracing
1973 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1974 subsequent syscall. Simply resume using the inf-ptrace layer,
1975 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1977 /* Note that gdbarch_get_syscall_number may access registers, hence
1979 registers_changed ();
1980 if (linux_nat_prepare_to_resume
!= NULL
)
1981 linux_nat_prepare_to_resume (lp
);
1982 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
1983 lp
->step
, GDB_SIGNAL_0
);
1988 /* Handle a GNU/Linux extended wait response. If we see a clone
1989 event, we need to add the new LWP to our list (and not report the
1990 trap to higher layers). This function returns non-zero if the
1991 event should be ignored and we should wait again. If STOPPING is
1992 true, the new LWP remains stopped, otherwise it is continued. */
1995 linux_handle_extended_wait (struct lwp_info
*lp
, int status
,
1998 int pid
= ptid_get_lwp (lp
->ptid
);
1999 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
2000 int event
= status
>> 16;
2002 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
2003 || event
== PTRACE_EVENT_CLONE
)
2005 unsigned long new_pid
;
2008 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
2010 /* If we haven't already seen the new PID stop, wait for it now. */
2011 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
2013 /* The new child has a pending SIGSTOP. We can't affect it until it
2014 hits the SIGSTOP, but we're already attached. */
2015 ret
= my_waitpid (new_pid
, &status
,
2016 (event
== PTRACE_EVENT_CLONE
) ? __WCLONE
: 0);
2018 perror_with_name (_("waiting for new child"));
2019 else if (ret
!= new_pid
)
2020 internal_error (__FILE__
, __LINE__
,
2021 _("wait returned unexpected PID %d"), ret
);
2022 else if (!WIFSTOPPED (status
))
2023 internal_error (__FILE__
, __LINE__
,
2024 _("wait returned unexpected status 0x%x"), status
);
2027 ourstatus
->value
.related_pid
= ptid_build (new_pid
, new_pid
, 0);
2029 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
2031 /* The arch-specific native code may need to know about new
2032 forks even if those end up never mapped to an
2034 if (linux_nat_new_fork
!= NULL
)
2035 linux_nat_new_fork (lp
, new_pid
);
2038 if (event
== PTRACE_EVENT_FORK
2039 && linux_fork_checkpointing_p (ptid_get_pid (lp
->ptid
)))
2041 /* Handle checkpointing by linux-fork.c here as a special
2042 case. We don't want the follow-fork-mode or 'catch fork'
2043 to interfere with this. */
2045 /* This won't actually modify the breakpoint list, but will
2046 physically remove the breakpoints from the child. */
2047 detach_breakpoints (ptid_build (new_pid
, new_pid
, 0));
2049 /* Retain child fork in ptrace (stopped) state. */
2050 if (!find_fork_pid (new_pid
))
2053 /* Report as spurious, so that infrun doesn't want to follow
2054 this fork. We're actually doing an infcall in
2056 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
2058 /* Report the stop to the core. */
2062 if (event
== PTRACE_EVENT_FORK
)
2063 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
2064 else if (event
== PTRACE_EVENT_VFORK
)
2065 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
2068 struct lwp_info
*new_lp
;
2070 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2072 if (debug_linux_nat
)
2073 fprintf_unfiltered (gdb_stdlog
,
2074 "LHEW: Got clone event "
2075 "from LWP %d, new child is LWP %ld\n",
2078 new_lp
= add_lwp (ptid_build (ptid_get_pid (lp
->ptid
), new_pid
, 0));
2080 new_lp
->stopped
= 1;
2082 if (WSTOPSIG (status
) != SIGSTOP
)
2084 /* This can happen if someone starts sending signals to
2085 the new thread before it gets a chance to run, which
2086 have a lower number than SIGSTOP (e.g. SIGUSR1).
2087 This is an unlikely case, and harder to handle for
2088 fork / vfork than for clone, so we do not try - but
2089 we handle it for clone events here. We'll send
2090 the other signal on to the thread below. */
2092 new_lp
->signalled
= 1;
2096 struct thread_info
*tp
;
2098 /* When we stop for an event in some other thread, and
2099 pull the thread list just as this thread has cloned,
2100 we'll have seen the new thread in the thread_db list
2101 before handling the CLONE event (glibc's
2102 pthread_create adds the new thread to the thread list
2103 before clone'ing, and has the kernel fill in the
2104 thread's tid on the clone call with
2105 CLONE_PARENT_SETTID). If that happened, and the core
2106 had requested the new thread to stop, we'll have
2107 killed it with SIGSTOP. But since SIGSTOP is not an
2108 RT signal, it can only be queued once. We need to be
2109 careful to not resume the LWP if we wanted it to
2110 stop. In that case, we'll leave the SIGSTOP pending.
2111 It will later be reported as GDB_SIGNAL_0. */
2112 tp
= find_thread_ptid (new_lp
->ptid
);
2113 if (tp
!= NULL
&& tp
->stop_requested
)
2114 new_lp
->last_resume_kind
= resume_stop
;
2121 /* Add the new thread to GDB's lists as soon as possible
2124 1) the frontend doesn't have to wait for a stop to
2127 2) we tag it with the correct running state. */
2129 /* If the thread_db layer is active, let it know about
2130 this new thread, and add it to GDB's list. */
2131 if (!thread_db_attach_lwp (new_lp
->ptid
))
2133 /* We're not using thread_db. Add it to GDB's
2135 target_post_attach (ptid_get_lwp (new_lp
->ptid
));
2136 add_thread (new_lp
->ptid
);
2141 set_running (new_lp
->ptid
, 1);
2142 set_executing (new_lp
->ptid
, 1);
2143 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2145 new_lp
->last_resume_kind
= resume_continue
;
2151 /* We created NEW_LP so it cannot yet contain STATUS. */
2152 gdb_assert (new_lp
->status
== 0);
2154 /* Save the wait status to report later. */
2155 if (debug_linux_nat
)
2156 fprintf_unfiltered (gdb_stdlog
,
2157 "LHEW: waitpid of new LWP %ld, "
2158 "saving status %s\n",
2159 (long) ptid_get_lwp (new_lp
->ptid
),
2160 status_to_str (status
));
2161 new_lp
->status
= status
;
2164 /* Note the need to use the low target ops to resume, to
2165 handle resuming with PT_SYSCALL if we have syscall
2169 new_lp
->resumed
= 1;
2173 gdb_assert (new_lp
->last_resume_kind
== resume_continue
);
2174 if (debug_linux_nat
)
2175 fprintf_unfiltered (gdb_stdlog
,
2176 "LHEW: resuming new LWP %ld\n",
2177 ptid_get_lwp (new_lp
->ptid
));
2178 if (linux_nat_prepare_to_resume
!= NULL
)
2179 linux_nat_prepare_to_resume (new_lp
);
2180 linux_ops
->to_resume (linux_ops
, pid_to_ptid (new_pid
),
2182 new_lp
->stopped
= 0;
2186 if (debug_linux_nat
)
2187 fprintf_unfiltered (gdb_stdlog
,
2188 "LHEW: resuming parent LWP %d\n", pid
);
2189 if (linux_nat_prepare_to_resume
!= NULL
)
2190 linux_nat_prepare_to_resume (lp
);
2191 linux_ops
->to_resume (linux_ops
,
2192 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
2201 if (event
== PTRACE_EVENT_EXEC
)
2203 if (debug_linux_nat
)
2204 fprintf_unfiltered (gdb_stdlog
,
2205 "LHEW: Got exec event from LWP %ld\n",
2206 ptid_get_lwp (lp
->ptid
));
2208 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2209 ourstatus
->value
.execd_pathname
2210 = xstrdup (linux_child_pid_to_exec_file (NULL
, pid
));
2215 if (event
== PTRACE_EVENT_VFORK_DONE
)
2217 if (current_inferior ()->waiting_for_vfork_done
)
2219 if (debug_linux_nat
)
2220 fprintf_unfiltered (gdb_stdlog
,
2221 "LHEW: Got expected PTRACE_EVENT_"
2222 "VFORK_DONE from LWP %ld: stopping\n",
2223 ptid_get_lwp (lp
->ptid
));
2225 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2229 if (debug_linux_nat
)
2230 fprintf_unfiltered (gdb_stdlog
,
2231 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2232 "from LWP %ld: resuming\n",
2233 ptid_get_lwp (lp
->ptid
));
2234 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2238 internal_error (__FILE__
, __LINE__
,
2239 _("unknown ptrace event %d"), event
);
2242 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2246 wait_lwp (struct lwp_info
*lp
)
2250 int thread_dead
= 0;
2253 gdb_assert (!lp
->stopped
);
2254 gdb_assert (lp
->status
== 0);
2256 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2257 block_child_signals (&prev_mask
);
2261 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2262 was right and we should just call sigsuspend. */
2264 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, WNOHANG
);
2265 if (pid
== -1 && errno
== ECHILD
)
2266 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, __WCLONE
| WNOHANG
);
2267 if (pid
== -1 && errno
== ECHILD
)
2269 /* The thread has previously exited. We need to delete it
2270 now because, for some vendor 2.4 kernels with NPTL
2271 support backported, there won't be an exit event unless
2272 it is the main thread. 2.6 kernels will report an exit
2273 event for each thread that exits, as expected. */
2275 if (debug_linux_nat
)
2276 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2277 target_pid_to_str (lp
->ptid
));
2282 /* Bugs 10970, 12702.
2283 Thread group leader may have exited in which case we'll lock up in
2284 waitpid if there are other threads, even if they are all zombies too.
2285 Basically, we're not supposed to use waitpid this way.
2286 __WCLONE is not applicable for the leader so we can't use that.
2287 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2288 process; it gets ESRCH both for the zombie and for running processes.
2290 As a workaround, check if we're waiting for the thread group leader and
2291 if it's a zombie, and avoid calling waitpid if it is.
2293 This is racy, what if the tgl becomes a zombie right after we check?
2294 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2295 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2297 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
)
2298 && linux_proc_pid_is_zombie (ptid_get_lwp (lp
->ptid
)))
2301 if (debug_linux_nat
)
2302 fprintf_unfiltered (gdb_stdlog
,
2303 "WL: Thread group leader %s vanished.\n",
2304 target_pid_to_str (lp
->ptid
));
2308 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2309 get invoked despite our caller had them intentionally blocked by
2310 block_child_signals. This is sensitive only to the loop of
2311 linux_nat_wait_1 and there if we get called my_waitpid gets called
2312 again before it gets to sigsuspend so we can safely let the handlers
2313 get executed here. */
2315 sigsuspend (&suspend_mask
);
2318 restore_child_signals_mask (&prev_mask
);
2322 gdb_assert (pid
== ptid_get_lwp (lp
->ptid
));
2324 if (debug_linux_nat
)
2326 fprintf_unfiltered (gdb_stdlog
,
2327 "WL: waitpid %s received %s\n",
2328 target_pid_to_str (lp
->ptid
),
2329 status_to_str (status
));
2332 /* Check if the thread has exited. */
2333 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2336 if (debug_linux_nat
)
2337 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2338 target_pid_to_str (lp
->ptid
));
2348 gdb_assert (WIFSTOPPED (status
));
2351 /* Handle GNU/Linux's syscall SIGTRAPs. */
2352 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2354 /* No longer need the sysgood bit. The ptrace event ends up
2355 recorded in lp->waitstatus if we care for it. We can carry
2356 on handling the event like a regular SIGTRAP from here
2358 status
= W_STOPCODE (SIGTRAP
);
2359 if (linux_handle_syscall_trap (lp
, 1))
2360 return wait_lwp (lp
);
2363 /* Handle GNU/Linux's extended waitstatus for trace events. */
2364 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2366 if (debug_linux_nat
)
2367 fprintf_unfiltered (gdb_stdlog
,
2368 "WL: Handling extended status 0x%06x\n",
2370 if (linux_handle_extended_wait (lp
, status
, 1))
2371 return wait_lwp (lp
);
2377 /* Send a SIGSTOP to LP. */
2380 stop_callback (struct lwp_info
*lp
, void *data
)
2382 if (!lp
->stopped
&& !lp
->signalled
)
2386 if (debug_linux_nat
)
2388 fprintf_unfiltered (gdb_stdlog
,
2389 "SC: kill %s **<SIGSTOP>**\n",
2390 target_pid_to_str (lp
->ptid
));
2393 ret
= kill_lwp (ptid_get_lwp (lp
->ptid
), SIGSTOP
);
2394 if (debug_linux_nat
)
2396 fprintf_unfiltered (gdb_stdlog
,
2397 "SC: lwp kill %d %s\n",
2399 errno
? safe_strerror (errno
) : "ERRNO-OK");
2403 gdb_assert (lp
->status
== 0);
2409 /* Request a stop on LWP. */
2412 linux_stop_lwp (struct lwp_info
*lwp
)
2414 stop_callback (lwp
, NULL
);
2417 /* Return non-zero if LWP PID has a pending SIGINT. */
2420 linux_nat_has_pending_sigint (int pid
)
2422 sigset_t pending
, blocked
, ignored
;
2424 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2426 if (sigismember (&pending
, SIGINT
)
2427 && !sigismember (&ignored
, SIGINT
))
2433 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2436 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2438 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2439 flag to consume the next one. */
2440 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2441 && WSTOPSIG (lp
->status
) == SIGINT
)
2444 lp
->ignore_sigint
= 1;
2449 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2450 This function is called after we know the LWP has stopped; if the LWP
2451 stopped before the expected SIGINT was delivered, then it will never have
2452 arrived. Also, if the signal was delivered to a shared queue and consumed
2453 by a different thread, it will never be delivered to this LWP. */
2456 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2458 if (!lp
->ignore_sigint
)
2461 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp
->ptid
)))
2463 if (debug_linux_nat
)
2464 fprintf_unfiltered (gdb_stdlog
,
2465 "MCIS: Clearing bogus flag for %s\n",
2466 target_pid_to_str (lp
->ptid
));
2467 lp
->ignore_sigint
= 0;
2471 /* Fetch the possible triggered data watchpoint info and store it in
2474 On some archs, like x86, that use debug registers to set
2475 watchpoints, it's possible that the way to know which watched
2476 address trapped, is to check the register that is used to select
2477 which address to watch. Problem is, between setting the watchpoint
2478 and reading back which data address trapped, the user may change
2479 the set of watchpoints, and, as a consequence, GDB changes the
2480 debug registers in the inferior. To avoid reading back a stale
2481 stopped-data-address when that happens, we cache in LP the fact
2482 that a watchpoint trapped, and the corresponding data address, as
2483 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2484 registers meanwhile, we have the cached data we can rely on. */
2487 save_sigtrap (struct lwp_info
*lp
)
2489 struct cleanup
*old_chain
;
2491 if (linux_ops
->to_stopped_by_watchpoint
== NULL
)
2493 lp
->stopped_by_watchpoint
= 0;
2497 old_chain
= save_inferior_ptid ();
2498 inferior_ptid
= lp
->ptid
;
2500 lp
->stopped_by_watchpoint
= linux_ops
->to_stopped_by_watchpoint (linux_ops
);
2502 if (lp
->stopped_by_watchpoint
)
2504 if (linux_ops
->to_stopped_data_address
!= NULL
)
2505 lp
->stopped_data_address_p
=
2506 linux_ops
->to_stopped_data_address (¤t_target
,
2507 &lp
->stopped_data_address
);
2509 lp
->stopped_data_address_p
= 0;
2512 do_cleanups (old_chain
);
2515 /* See save_sigtrap. */
2518 linux_nat_stopped_by_watchpoint (struct target_ops
*ops
)
2520 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2522 gdb_assert (lp
!= NULL
);
2524 return lp
->stopped_by_watchpoint
;
2528 linux_nat_stopped_data_address (struct target_ops
*ops
, CORE_ADDR
*addr_p
)
2530 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2532 gdb_assert (lp
!= NULL
);
2534 *addr_p
= lp
->stopped_data_address
;
2536 return lp
->stopped_data_address_p
;
2539 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2542 sigtrap_is_event (int status
)
2544 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2547 /* SIGTRAP-like events recognizer. */
2549 static int (*linux_nat_status_is_event
) (int status
) = sigtrap_is_event
;
2551 /* Check for SIGTRAP-like events in LP. */
2554 linux_nat_lp_status_is_event (struct lwp_info
*lp
)
2556 /* We check for lp->waitstatus in addition to lp->status, because we can
2557 have pending process exits recorded in lp->status
2558 and W_EXITCODE(0,0) == 0. We should probably have an additional
2559 lp->status_p flag. */
2561 return (lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
2562 && linux_nat_status_is_event (lp
->status
));
2565 /* Set alternative SIGTRAP-like events recognizer. If
2566 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2570 linux_nat_set_status_is_event (struct target_ops
*t
,
2571 int (*status_is_event
) (int status
))
2573 linux_nat_status_is_event
= status_is_event
;
2576 /* Wait until LP is stopped. */
2579 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2581 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2583 /* If this is a vfork parent, bail out, it is not going to report
2584 any SIGSTOP until the vfork is done with. */
2585 if (inf
->vfork_child
!= NULL
)
2592 status
= wait_lwp (lp
);
2596 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2597 && WSTOPSIG (status
) == SIGINT
)
2599 lp
->ignore_sigint
= 0;
2602 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2604 if (debug_linux_nat
)
2605 fprintf_unfiltered (gdb_stdlog
,
2606 "PTRACE_CONT %s, 0, 0 (%s) "
2607 "(discarding SIGINT)\n",
2608 target_pid_to_str (lp
->ptid
),
2609 errno
? safe_strerror (errno
) : "OK");
2611 return stop_wait_callback (lp
, NULL
);
2614 maybe_clear_ignore_sigint (lp
);
2616 if (WSTOPSIG (status
) != SIGSTOP
)
2618 /* The thread was stopped with a signal other than SIGSTOP. */
2622 if (debug_linux_nat
)
2623 fprintf_unfiltered (gdb_stdlog
,
2624 "SWC: Pending event %s in %s\n",
2625 status_to_str ((int) status
),
2626 target_pid_to_str (lp
->ptid
));
2628 /* Save the sigtrap event. */
2629 lp
->status
= status
;
2630 gdb_assert (lp
->signalled
);
2634 /* We caught the SIGSTOP that we intended to catch, so
2635 there's no SIGSTOP pending. */
2637 if (debug_linux_nat
)
2638 fprintf_unfiltered (gdb_stdlog
,
2639 "SWC: Delayed SIGSTOP caught for %s.\n",
2640 target_pid_to_str (lp
->ptid
));
2642 /* Reset SIGNALLED only after the stop_wait_callback call
2643 above as it does gdb_assert on SIGNALLED. */
2651 /* Return non-zero if LP has a wait status pending. */
2654 status_callback (struct lwp_info
*lp
, void *data
)
2656 /* Only report a pending wait status if we pretend that this has
2657 indeed been resumed. */
2661 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2663 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2664 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2665 0', so a clean process exit can not be stored pending in
2666 lp->status, it is indistinguishable from
2667 no-pending-status. */
2671 if (lp
->status
!= 0)
2677 /* Return non-zero if LP isn't stopped. */
2680 running_callback (struct lwp_info
*lp
, void *data
)
2682 return (!lp
->stopped
2683 || ((lp
->status
!= 0
2684 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2688 /* Count the LWP's that have had events. */
2691 count_events_callback (struct lwp_info
*lp
, void *data
)
2695 gdb_assert (count
!= NULL
);
2697 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2698 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2704 /* Select the LWP (if any) that is currently being single-stepped. */
2707 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2709 if (lp
->last_resume_kind
== resume_step
2716 /* Select the Nth LWP that has had a SIGTRAP event. */
2719 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2721 int *selector
= data
;
2723 gdb_assert (selector
!= NULL
);
2725 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2726 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2727 if ((*selector
)-- == 0)
2734 cancel_breakpoint (struct lwp_info
*lp
)
2736 /* Arrange for a breakpoint to be hit again later. We don't keep
2737 the SIGTRAP status and don't forward the SIGTRAP signal to the
2738 LWP. We will handle the current event, eventually we will resume
2739 this LWP, and this breakpoint will trap again.
2741 If we do not do this, then we run the risk that the user will
2742 delete or disable the breakpoint, but the LWP will have already
2745 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2746 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2749 pc
= regcache_read_pc (regcache
) - target_decr_pc_after_break (gdbarch
);
2750 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2752 if (debug_linux_nat
)
2753 fprintf_unfiltered (gdb_stdlog
,
2754 "CB: Push back breakpoint for %s\n",
2755 target_pid_to_str (lp
->ptid
));
2757 /* Back up the PC if necessary. */
2758 if (target_decr_pc_after_break (gdbarch
))
2759 regcache_write_pc (regcache
, pc
);
2767 cancel_breakpoints_callback (struct lwp_info
*lp
, void *data
)
2769 struct lwp_info
*event_lp
= data
;
2771 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2775 /* If a LWP other than the LWP that we're reporting an event for has
2776 hit a GDB breakpoint (as opposed to some random trap signal),
2777 then just arrange for it to hit it again later. We don't keep
2778 the SIGTRAP status and don't forward the SIGTRAP signal to the
2779 LWP. We will handle the current event, eventually we will resume
2780 all LWPs, and this one will get its breakpoint trap again.
2782 If we do not do this, then we run the risk that the user will
2783 delete or disable the breakpoint, but the LWP will have already
2786 if (linux_nat_lp_status_is_event (lp
)
2787 && cancel_breakpoint (lp
))
2788 /* Throw away the SIGTRAP. */
2794 /* Select one LWP out of those that have events pending. */
2797 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2800 int random_selector
;
2801 struct lwp_info
*event_lp
;
2803 /* Record the wait status for the original LWP. */
2804 (*orig_lp
)->status
= *status
;
2806 /* Give preference to any LWP that is being single-stepped. */
2807 event_lp
= iterate_over_lwps (filter
,
2808 select_singlestep_lwp_callback
, NULL
);
2809 if (event_lp
!= NULL
)
2811 if (debug_linux_nat
)
2812 fprintf_unfiltered (gdb_stdlog
,
2813 "SEL: Select single-step %s\n",
2814 target_pid_to_str (event_lp
->ptid
));
2818 /* No single-stepping LWP. Select one at random, out of those
2819 which have had SIGTRAP events. */
2821 /* First see how many SIGTRAP events we have. */
2822 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2824 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2825 random_selector
= (int)
2826 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2828 if (debug_linux_nat
&& num_events
> 1)
2829 fprintf_unfiltered (gdb_stdlog
,
2830 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2831 num_events
, random_selector
);
2833 event_lp
= iterate_over_lwps (filter
,
2834 select_event_lwp_callback
,
2838 if (event_lp
!= NULL
)
2840 /* Switch the event LWP. */
2841 *orig_lp
= event_lp
;
2842 *status
= event_lp
->status
;
2845 /* Flush the wait status for the event LWP. */
2846 (*orig_lp
)->status
= 0;
2849 /* Return non-zero if LP has been resumed. */
2852 resumed_callback (struct lwp_info
*lp
, void *data
)
2857 /* Stop an active thread, verify it still exists, then resume it. If
2858 the thread ends up with a pending status, then it is not resumed,
2859 and *DATA (really a pointer to int), is set. */
2862 stop_and_resume_callback (struct lwp_info
*lp
, void *data
)
2864 int *new_pending_p
= data
;
2868 ptid_t ptid
= lp
->ptid
;
2870 stop_callback (lp
, NULL
);
2871 stop_wait_callback (lp
, NULL
);
2873 /* Resume if the lwp still exists, and the core wanted it
2875 lp
= find_lwp_pid (ptid
);
2878 if (lp
->last_resume_kind
== resume_stop
2881 /* The core wanted the LWP to stop. Even if it stopped
2882 cleanly (with SIGSTOP), leave the event pending. */
2883 if (debug_linux_nat
)
2884 fprintf_unfiltered (gdb_stdlog
,
2885 "SARC: core wanted LWP %ld stopped "
2886 "(leaving SIGSTOP pending)\n",
2887 ptid_get_lwp (lp
->ptid
));
2888 lp
->status
= W_STOPCODE (SIGSTOP
);
2891 if (lp
->status
== 0)
2893 if (debug_linux_nat
)
2894 fprintf_unfiltered (gdb_stdlog
,
2895 "SARC: re-resuming LWP %ld\n",
2896 ptid_get_lwp (lp
->ptid
));
2897 resume_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2901 if (debug_linux_nat
)
2902 fprintf_unfiltered (gdb_stdlog
,
2903 "SARC: not re-resuming LWP %ld "
2905 ptid_get_lwp (lp
->ptid
));
2914 /* Check if we should go on and pass this event to common code.
2915 Return the affected lwp if we are, or NULL otherwise. If we stop
2916 all lwps temporarily, we may end up with new pending events in some
2917 other lwp. In that case set *NEW_PENDING_P to true. */
2919 static struct lwp_info
*
2920 linux_nat_filter_event (int lwpid
, int status
, int *new_pending_p
)
2922 struct lwp_info
*lp
;
2926 lp
= find_lwp_pid (pid_to_ptid (lwpid
));
2928 /* Check for stop events reported by a process we didn't already
2929 know about - anything not already in our LWP list.
2931 If we're expecting to receive stopped processes after
2932 fork, vfork, and clone events, then we'll just add the
2933 new one to our list and go back to waiting for the event
2934 to be reported - the stopped process might be returned
2935 from waitpid before or after the event is.
2937 But note the case of a non-leader thread exec'ing after the
2938 leader having exited, and gone from our lists. The non-leader
2939 thread changes its tid to the tgid. */
2941 if (WIFSTOPPED (status
) && lp
== NULL
2942 && (WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 == PTRACE_EVENT_EXEC
))
2944 /* A multi-thread exec after we had seen the leader exiting. */
2945 if (debug_linux_nat
)
2946 fprintf_unfiltered (gdb_stdlog
,
2947 "LLW: Re-adding thread group leader LWP %d.\n",
2950 lp
= add_lwp (ptid_build (lwpid
, lwpid
, 0));
2953 add_thread (lp
->ptid
);
2956 if (WIFSTOPPED (status
) && !lp
)
2958 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2962 /* Make sure we don't report an event for the exit of an LWP not in
2963 our list, i.e. not part of the current process. This can happen
2964 if we detach from a program we originally forked and then it
2966 if (!WIFSTOPPED (status
) && !lp
)
2969 /* This LWP is stopped now. (And if dead, this prevents it from
2970 ever being continued.) */
2973 /* Handle GNU/Linux's syscall SIGTRAPs. */
2974 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2976 /* No longer need the sysgood bit. The ptrace event ends up
2977 recorded in lp->waitstatus if we care for it. We can carry
2978 on handling the event like a regular SIGTRAP from here
2980 status
= W_STOPCODE (SIGTRAP
);
2981 if (linux_handle_syscall_trap (lp
, 0))
2985 /* Handle GNU/Linux's extended waitstatus for trace events. */
2986 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2988 if (debug_linux_nat
)
2989 fprintf_unfiltered (gdb_stdlog
,
2990 "LLW: Handling extended status 0x%06x\n",
2992 if (linux_handle_extended_wait (lp
, status
, 0))
2996 if (linux_nat_status_is_event (status
))
2999 /* Check if the thread has exited. */
3000 if ((WIFEXITED (status
) || WIFSIGNALED (status
))
3001 && num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
3003 /* If this is the main thread, we must stop all threads and verify
3004 if they are still alive. This is because in the nptl thread model
3005 on Linux 2.4, there is no signal issued for exiting LWPs
3006 other than the main thread. We only get the main thread exit
3007 signal once all child threads have already exited. If we
3008 stop all the threads and use the stop_wait_callback to check
3009 if they have exited we can determine whether this signal
3010 should be ignored or whether it means the end of the debugged
3011 application, regardless of which threading model is being
3013 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
))
3015 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
3016 stop_and_resume_callback
, new_pending_p
);
3019 if (debug_linux_nat
)
3020 fprintf_unfiltered (gdb_stdlog
,
3021 "LLW: %s exited.\n",
3022 target_pid_to_str (lp
->ptid
));
3024 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
3026 /* If there is at least one more LWP, then the exit signal
3027 was not the end of the debugged application and should be
3034 /* Check if the current LWP has previously exited. In the nptl
3035 thread model, LWPs other than the main thread do not issue
3036 signals when they exit so we must check whenever the thread has
3037 stopped. A similar check is made in stop_wait_callback(). */
3038 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1 && !linux_thread_alive (lp
->ptid
))
3040 ptid_t ptid
= pid_to_ptid (ptid_get_pid (lp
->ptid
));
3042 if (debug_linux_nat
)
3043 fprintf_unfiltered (gdb_stdlog
,
3044 "LLW: %s exited.\n",
3045 target_pid_to_str (lp
->ptid
));
3049 /* Make sure there is at least one thread running. */
3050 gdb_assert (iterate_over_lwps (ptid
, running_callback
, NULL
));
3052 /* Discard the event. */
3056 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3057 an attempt to stop an LWP. */
3059 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3061 if (debug_linux_nat
)
3062 fprintf_unfiltered (gdb_stdlog
,
3063 "LLW: Delayed SIGSTOP caught for %s.\n",
3064 target_pid_to_str (lp
->ptid
));
3068 if (lp
->last_resume_kind
!= resume_stop
)
3070 /* This is a delayed SIGSTOP. */
3072 registers_changed ();
3074 if (linux_nat_prepare_to_resume
!= NULL
)
3075 linux_nat_prepare_to_resume (lp
);
3076 linux_ops
->to_resume (linux_ops
,
3077 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3078 lp
->step
, GDB_SIGNAL_0
);
3079 if (debug_linux_nat
)
3080 fprintf_unfiltered (gdb_stdlog
,
3081 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3083 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3084 target_pid_to_str (lp
->ptid
));
3087 gdb_assert (lp
->resumed
);
3089 /* Discard the event. */
3094 /* Make sure we don't report a SIGINT that we have already displayed
3095 for another thread. */
3096 if (lp
->ignore_sigint
3097 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3099 if (debug_linux_nat
)
3100 fprintf_unfiltered (gdb_stdlog
,
3101 "LLW: Delayed SIGINT caught for %s.\n",
3102 target_pid_to_str (lp
->ptid
));
3104 /* This is a delayed SIGINT. */
3105 lp
->ignore_sigint
= 0;
3107 registers_changed ();
3108 if (linux_nat_prepare_to_resume
!= NULL
)
3109 linux_nat_prepare_to_resume (lp
);
3110 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3111 lp
->step
, GDB_SIGNAL_0
);
3112 if (debug_linux_nat
)
3113 fprintf_unfiltered (gdb_stdlog
,
3114 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3116 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3117 target_pid_to_str (lp
->ptid
));
3120 gdb_assert (lp
->resumed
);
3122 /* Discard the event. */
3126 /* An interesting event. */
3128 lp
->status
= status
;
3132 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3133 their exits until all other threads in the group have exited. */
3136 check_zombie_leaders (void)
3138 struct inferior
*inf
;
3142 struct lwp_info
*leader_lp
;
3147 leader_lp
= find_lwp_pid (pid_to_ptid (inf
->pid
));
3148 if (leader_lp
!= NULL
3149 /* Check if there are other threads in the group, as we may
3150 have raced with the inferior simply exiting. */
3151 && num_lwps (inf
->pid
) > 1
3152 && linux_proc_pid_is_zombie (inf
->pid
))
3154 if (debug_linux_nat
)
3155 fprintf_unfiltered (gdb_stdlog
,
3156 "CZL: Thread group leader %d zombie "
3157 "(it exited, or another thread execd).\n",
3160 /* A leader zombie can mean one of two things:
3162 - It exited, and there's an exit status pending
3163 available, or only the leader exited (not the whole
3164 program). In the latter case, we can't waitpid the
3165 leader's exit status until all other threads are gone.
3167 - There are 3 or more threads in the group, and a thread
3168 other than the leader exec'd. On an exec, the Linux
3169 kernel destroys all other threads (except the execing
3170 one) in the thread group, and resets the execing thread's
3171 tid to the tgid. No exit notification is sent for the
3172 execing thread -- from the ptracer's perspective, it
3173 appears as though the execing thread just vanishes.
3174 Until we reap all other threads except the leader and the
3175 execing thread, the leader will be zombie, and the
3176 execing thread will be in `D (disc sleep)'. As soon as
3177 all other threads are reaped, the execing thread changes
3178 it's tid to the tgid, and the previous (zombie) leader
3179 vanishes, giving place to the "new" leader. We could try
3180 distinguishing the exit and exec cases, by waiting once
3181 more, and seeing if something comes out, but it doesn't
3182 sound useful. The previous leader _does_ go away, and
3183 we'll re-add the new one once we see the exec event
3184 (which is just the same as what would happen if the
3185 previous leader did exit voluntarily before some other
3188 if (debug_linux_nat
)
3189 fprintf_unfiltered (gdb_stdlog
,
3190 "CZL: Thread group leader %d vanished.\n",
3192 exit_lwp (leader_lp
);
3198 linux_nat_wait_1 (struct target_ops
*ops
,
3199 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3202 static sigset_t prev_mask
;
3203 enum resume_kind last_resume_kind
;
3204 struct lwp_info
*lp
;
3207 if (debug_linux_nat
)
3208 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3210 /* The first time we get here after starting a new inferior, we may
3211 not have added it to the LWP list yet - this is the earliest
3212 moment at which we know its PID. */
3213 if (ptid_is_pid (inferior_ptid
))
3215 /* Upgrade the main thread's ptid. */
3216 thread_change_ptid (inferior_ptid
,
3217 ptid_build (ptid_get_pid (inferior_ptid
),
3218 ptid_get_pid (inferior_ptid
), 0));
3220 lp
= add_initial_lwp (inferior_ptid
);
3224 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3225 block_child_signals (&prev_mask
);
3231 /* First check if there is a LWP with a wait status pending. */
3232 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3234 /* Any LWP in the PTID group that's been resumed will do. */
3235 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3238 if (debug_linux_nat
&& lp
->status
)
3239 fprintf_unfiltered (gdb_stdlog
,
3240 "LLW: Using pending wait status %s for %s.\n",
3241 status_to_str (lp
->status
),
3242 target_pid_to_str (lp
->ptid
));
3245 else if (ptid_lwp_p (ptid
))
3247 if (debug_linux_nat
)
3248 fprintf_unfiltered (gdb_stdlog
,
3249 "LLW: Waiting for specific LWP %s.\n",
3250 target_pid_to_str (ptid
));
3252 /* We have a specific LWP to check. */
3253 lp
= find_lwp_pid (ptid
);
3256 if (debug_linux_nat
&& lp
->status
)
3257 fprintf_unfiltered (gdb_stdlog
,
3258 "LLW: Using pending wait status %s for %s.\n",
3259 status_to_str (lp
->status
),
3260 target_pid_to_str (lp
->ptid
));
3262 /* We check for lp->waitstatus in addition to lp->status,
3263 because we can have pending process exits recorded in
3264 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3265 an additional lp->status_p flag. */
3266 if (lp
->status
== 0 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3270 if (!target_can_async_p ())
3272 /* Causes SIGINT to be passed on to the attached process. */
3276 /* But if we don't find a pending event, we'll have to wait. */
3282 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3285 - If the thread group leader exits while other threads in the
3286 thread group still exist, waitpid(TGID, ...) hangs. That
3287 waitpid won't return an exit status until the other threads
3288 in the group are reapped.
3290 - When a non-leader thread execs, that thread just vanishes
3291 without reporting an exit (so we'd hang if we waited for it
3292 explicitly in that case). The exec event is reported to
3296 lwpid
= my_waitpid (-1, &status
, __WCLONE
| WNOHANG
);
3297 if (lwpid
== 0 || (lwpid
== -1 && errno
== ECHILD
))
3298 lwpid
= my_waitpid (-1, &status
, WNOHANG
);
3300 if (debug_linux_nat
)
3301 fprintf_unfiltered (gdb_stdlog
,
3302 "LNW: waitpid(-1, ...) returned %d, %s\n",
3303 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3307 /* If this is true, then we paused LWPs momentarily, and may
3308 now have pending events to handle. */
3311 if (debug_linux_nat
)
3313 fprintf_unfiltered (gdb_stdlog
,
3314 "LLW: waitpid %ld received %s\n",
3315 (long) lwpid
, status_to_str (status
));
3318 lp
= linux_nat_filter_event (lwpid
, status
, &new_pending
);
3320 /* STATUS is now no longer valid, use LP->STATUS instead. */
3323 if (lp
&& !ptid_match (lp
->ptid
, ptid
))
3325 gdb_assert (lp
->resumed
);
3327 if (debug_linux_nat
)
3329 "LWP %ld got an event %06x, leaving pending.\n",
3330 ptid_get_lwp (lp
->ptid
), lp
->status
);
3332 if (WIFSTOPPED (lp
->status
))
3334 if (WSTOPSIG (lp
->status
) != SIGSTOP
)
3336 /* Cancel breakpoint hits. The breakpoint may
3337 be removed before we fetch events from this
3338 process to report to the core. It is best
3339 not to assume the moribund breakpoints
3340 heuristic always handles these cases --- it
3341 could be too many events go through to the
3342 core before this one is handled. All-stop
3343 always cancels breakpoint hits in all
3346 && linux_nat_lp_status_is_event (lp
)
3347 && cancel_breakpoint (lp
))
3349 /* Throw away the SIGTRAP. */
3352 if (debug_linux_nat
)
3354 "LLW: LWP %ld hit a breakpoint while"
3355 " waiting for another process;"
3357 ptid_get_lwp (lp
->ptid
));
3363 else if (WIFEXITED (lp
->status
) || WIFSIGNALED (lp
->status
))
3365 if (debug_linux_nat
)
3367 "Process %ld exited while stopping LWPs\n",
3368 ptid_get_lwp (lp
->ptid
));
3370 /* This was the last lwp in the process. Since
3371 events are serialized to GDB core, and we can't
3372 report this one right now, but GDB core and the
3373 other target layers will want to be notified
3374 about the exit code/signal, leave the status
3375 pending for the next time we're able to report
3378 /* Dead LWP's aren't expected to reported a pending
3382 /* Store the pending event in the waitstatus as
3383 well, because W_EXITCODE(0,0) == 0. */
3384 store_waitstatus (&lp
->waitstatus
, lp
->status
);
3393 /* Some LWP now has a pending event. Go all the way
3394 back to check it. */
3400 /* We got an event to report to the core. */
3404 /* Retry until nothing comes out of waitpid. A single
3405 SIGCHLD can indicate more than one child stopped. */
3409 /* Check for zombie thread group leaders. Those can't be reaped
3410 until all other threads in the thread group are. */
3411 check_zombie_leaders ();
3413 /* If there are no resumed children left, bail. We'd be stuck
3414 forever in the sigsuspend call below otherwise. */
3415 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3417 if (debug_linux_nat
)
3418 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3420 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3422 if (!target_can_async_p ())
3423 clear_sigint_trap ();
3425 restore_child_signals_mask (&prev_mask
);
3426 return minus_one_ptid
;
3429 /* No interesting event to report to the core. */
3431 if (target_options
& TARGET_WNOHANG
)
3433 if (debug_linux_nat
)
3434 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3436 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3437 restore_child_signals_mask (&prev_mask
);
3438 return minus_one_ptid
;
3441 /* We shouldn't end up here unless we want to try again. */
3442 gdb_assert (lp
== NULL
);
3444 /* Block until we get an event reported with SIGCHLD. */
3445 sigsuspend (&suspend_mask
);
3448 if (!target_can_async_p ())
3449 clear_sigint_trap ();
3453 status
= lp
->status
;
3456 /* Don't report signals that GDB isn't interested in, such as
3457 signals that are neither printed nor stopped upon. Stopping all
3458 threads can be a bit time-consuming so if we want decent
3459 performance with heavily multi-threaded programs, especially when
3460 they're using a high frequency timer, we'd better avoid it if we
3463 if (WIFSTOPPED (status
))
3465 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3467 /* When using hardware single-step, we need to report every signal.
3468 Otherwise, signals in pass_mask may be short-circuited. */
3470 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
)))
3472 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3473 here? It is not clear we should. GDB may not expect
3474 other threads to run. On the other hand, not resuming
3475 newly attached threads may cause an unwanted delay in
3476 getting them running. */
3477 registers_changed ();
3478 if (linux_nat_prepare_to_resume
!= NULL
)
3479 linux_nat_prepare_to_resume (lp
);
3480 linux_ops
->to_resume (linux_ops
,
3481 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3483 if (debug_linux_nat
)
3484 fprintf_unfiltered (gdb_stdlog
,
3485 "LLW: %s %s, %s (preempt 'handle')\n",
3487 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3488 target_pid_to_str (lp
->ptid
),
3489 (signo
!= GDB_SIGNAL_0
3490 ? strsignal (gdb_signal_to_host (signo
))
3498 /* Only do the below in all-stop, as we currently use SIGINT
3499 to implement target_stop (see linux_nat_stop) in
3501 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3503 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3504 forwarded to the entire process group, that is, all LWPs
3505 will receive it - unless they're using CLONE_THREAD to
3506 share signals. Since we only want to report it once, we
3507 mark it as ignored for all LWPs except this one. */
3508 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid
)),
3509 set_ignore_sigint
, NULL
);
3510 lp
->ignore_sigint
= 0;
3513 maybe_clear_ignore_sigint (lp
);
3517 /* This LWP is stopped now. */
3520 if (debug_linux_nat
)
3521 fprintf_unfiltered (gdb_stdlog
, "LLW: Candidate event %s in %s.\n",
3522 status_to_str (status
), target_pid_to_str (lp
->ptid
));
3526 /* Now stop all other LWP's ... */
3527 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3529 /* ... and wait until all of them have reported back that
3530 they're no longer running. */
3531 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3533 /* If we're not waiting for a specific LWP, choose an event LWP
3534 from among those that have had events. Giving equal priority
3535 to all LWPs that have had events helps prevent
3537 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3538 select_event_lwp (ptid
, &lp
, &status
);
3540 /* Now that we've selected our final event LWP, cancel any
3541 breakpoints in other LWPs that have hit a GDB breakpoint.
3542 See the comment in cancel_breakpoints_callback to find out
3544 iterate_over_lwps (minus_one_ptid
, cancel_breakpoints_callback
, lp
);
3546 /* We'll need this to determine whether to report a SIGSTOP as
3547 TARGET_WAITKIND_0. Need to take a copy because
3548 resume_clear_callback clears it. */
3549 last_resume_kind
= lp
->last_resume_kind
;
3551 /* In all-stop, from the core's perspective, all LWPs are now
3552 stopped until a new resume action is sent over. */
3553 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3558 last_resume_kind
= lp
->last_resume_kind
;
3559 resume_clear_callback (lp
, NULL
);
3562 if (linux_nat_status_is_event (status
))
3564 if (debug_linux_nat
)
3565 fprintf_unfiltered (gdb_stdlog
,
3566 "LLW: trap ptid is %s.\n",
3567 target_pid_to_str (lp
->ptid
));
3570 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3572 *ourstatus
= lp
->waitstatus
;
3573 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3576 store_waitstatus (ourstatus
, status
);
3578 if (debug_linux_nat
)
3579 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3581 restore_child_signals_mask (&prev_mask
);
3583 if (last_resume_kind
== resume_stop
3584 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3585 && WSTOPSIG (status
) == SIGSTOP
)
3587 /* A thread that has been requested to stop by GDB with
3588 target_stop, and it stopped cleanly, so report as SIG0. The
3589 use of SIGSTOP is an implementation detail. */
3590 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3593 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3594 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3597 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3602 /* Resume LWPs that are currently stopped without any pending status
3603 to report, but are resumed from the core's perspective. */
3606 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3608 ptid_t
*wait_ptid_p
= data
;
3613 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3615 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3616 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3617 CORE_ADDR pc
= regcache_read_pc (regcache
);
3619 gdb_assert (is_executing (lp
->ptid
));
3621 /* Don't bother if there's a breakpoint at PC that we'd hit
3622 immediately, and we're not waiting for this LWP. */
3623 if (!ptid_match (lp
->ptid
, *wait_ptid_p
))
3625 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
3629 if (debug_linux_nat
)
3630 fprintf_unfiltered (gdb_stdlog
,
3631 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3632 target_pid_to_str (lp
->ptid
),
3633 paddress (gdbarch
, pc
),
3636 registers_changed ();
3637 if (linux_nat_prepare_to_resume
!= NULL
)
3638 linux_nat_prepare_to_resume (lp
);
3639 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3640 lp
->step
, GDB_SIGNAL_0
);
3642 lp
->stopped_by_watchpoint
= 0;
3649 linux_nat_wait (struct target_ops
*ops
,
3650 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3655 if (debug_linux_nat
)
3657 char *options_string
;
3659 options_string
= target_options_to_string (target_options
);
3660 fprintf_unfiltered (gdb_stdlog
,
3661 "linux_nat_wait: [%s], [%s]\n",
3662 target_pid_to_str (ptid
),
3664 xfree (options_string
);
3667 /* Flush the async file first. */
3668 if (target_can_async_p ())
3669 async_file_flush ();
3671 /* Resume LWPs that are currently stopped without any pending status
3672 to report, but are resumed from the core's perspective. LWPs get
3673 in this state if we find them stopping at a time we're not
3674 interested in reporting the event (target_wait on a
3675 specific_process, for example, see linux_nat_wait_1), and
3676 meanwhile the event became uninteresting. Don't bother resuming
3677 LWPs we're not going to wait for if they'd stop immediately. */
3679 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3681 event_ptid
= linux_nat_wait_1 (ops
, ptid
, ourstatus
, target_options
);
3683 /* If we requested any event, and something came out, assume there
3684 may be more. If we requested a specific lwp or process, also
3685 assume there may be more. */
3686 if (target_can_async_p ()
3687 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3688 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3689 || !ptid_equal (ptid
, minus_one_ptid
)))
3692 /* Get ready for the next event. */
3693 if (target_can_async_p ())
3694 target_async (inferior_event_handler
, 0);
3700 kill_callback (struct lwp_info
*lp
, void *data
)
3702 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3705 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGKILL
);
3706 if (debug_linux_nat
)
3708 int save_errno
= errno
;
3710 fprintf_unfiltered (gdb_stdlog
,
3711 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3712 target_pid_to_str (lp
->ptid
),
3713 save_errno
? safe_strerror (save_errno
) : "OK");
3716 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3719 ptrace (PTRACE_KILL
, ptid_get_lwp (lp
->ptid
), 0, 0);
3720 if (debug_linux_nat
)
3722 int save_errno
= errno
;
3724 fprintf_unfiltered (gdb_stdlog
,
3725 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3726 target_pid_to_str (lp
->ptid
),
3727 save_errno
? safe_strerror (save_errno
) : "OK");
3734 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3738 /* We must make sure that there are no pending events (delayed
3739 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3740 program doesn't interfere with any following debugging session. */
3742 /* For cloned processes we must check both with __WCLONE and
3743 without, since the exit status of a cloned process isn't reported
3749 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, __WCLONE
);
3750 if (pid
!= (pid_t
) -1)
3752 if (debug_linux_nat
)
3753 fprintf_unfiltered (gdb_stdlog
,
3754 "KWC: wait %s received unknown.\n",
3755 target_pid_to_str (lp
->ptid
));
3756 /* The Linux kernel sometimes fails to kill a thread
3757 completely after PTRACE_KILL; that goes from the stop
3758 point in do_fork out to the one in
3759 get_signal_to_deliever and waits again. So kill it
3761 kill_callback (lp
, NULL
);
3764 while (pid
== ptid_get_lwp (lp
->ptid
));
3766 gdb_assert (pid
== -1 && errno
== ECHILD
);
3771 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, 0);
3772 if (pid
!= (pid_t
) -1)
3774 if (debug_linux_nat
)
3775 fprintf_unfiltered (gdb_stdlog
,
3776 "KWC: wait %s received unk.\n",
3777 target_pid_to_str (lp
->ptid
));
3778 /* See the call to kill_callback above. */
3779 kill_callback (lp
, NULL
);
3782 while (pid
== ptid_get_lwp (lp
->ptid
));
3784 gdb_assert (pid
== -1 && errno
== ECHILD
);
3789 linux_nat_kill (struct target_ops
*ops
)
3791 struct target_waitstatus last
;
3795 /* If we're stopped while forking and we haven't followed yet,
3796 kill the other task. We need to do this first because the
3797 parent will be sleeping if this is a vfork. */
3799 get_last_target_status (&last_ptid
, &last
);
3801 if (last
.kind
== TARGET_WAITKIND_FORKED
3802 || last
.kind
== TARGET_WAITKIND_VFORKED
)
3804 ptrace (PT_KILL
, ptid_get_pid (last
.value
.related_pid
), 0, 0);
3807 /* Let the arch-specific native code know this process is
3809 linux_nat_forget_process (ptid_get_pid (last
.value
.related_pid
));
3812 if (forks_exist_p ())
3813 linux_fork_killall ();
3816 ptid_t ptid
= pid_to_ptid (ptid_get_pid (inferior_ptid
));
3818 /* Stop all threads before killing them, since ptrace requires
3819 that the thread is stopped to sucessfully PTRACE_KILL. */
3820 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3821 /* ... and wait until all of them have reported back that
3822 they're no longer running. */
3823 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3825 /* Kill all LWP's ... */
3826 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3828 /* ... and wait until we've flushed all events. */
3829 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3832 target_mourn_inferior ();
3836 linux_nat_mourn_inferior (struct target_ops
*ops
)
3838 int pid
= ptid_get_pid (inferior_ptid
);
3840 purge_lwp_list (pid
);
3842 if (! forks_exist_p ())
3843 /* Normal case, no other forks available. */
3844 linux_ops
->to_mourn_inferior (ops
);
3846 /* Multi-fork case. The current inferior_ptid has exited, but
3847 there are other viable forks to debug. Delete the exiting
3848 one and context-switch to the first available. */
3849 linux_fork_mourn_inferior ();
3851 /* Let the arch-specific native code know this process is gone. */
3852 linux_nat_forget_process (pid
);
3855 /* Convert a native/host siginfo object, into/from the siginfo in the
3856 layout of the inferiors' architecture. */
3859 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3863 if (linux_nat_siginfo_fixup
!= NULL
)
3864 done
= linux_nat_siginfo_fixup (siginfo
, inf_siginfo
, direction
);
3866 /* If there was no callback, or the callback didn't do anything,
3867 then just do a straight memcpy. */
3871 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3873 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3877 static enum target_xfer_status
3878 linux_xfer_siginfo (struct target_ops
*ops
, enum target_object object
,
3879 const char *annex
, gdb_byte
*readbuf
,
3880 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3881 ULONGEST
*xfered_len
)
3885 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3887 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3888 gdb_assert (readbuf
|| writebuf
);
3890 pid
= ptid_get_lwp (inferior_ptid
);
3892 pid
= ptid_get_pid (inferior_ptid
);
3894 if (offset
> sizeof (siginfo
))
3895 return TARGET_XFER_E_IO
;
3898 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3900 return TARGET_XFER_E_IO
;
3902 /* When GDB is built as a 64-bit application, ptrace writes into
3903 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3904 inferior with a 64-bit GDB should look the same as debugging it
3905 with a 32-bit GDB, we need to convert it. GDB core always sees
3906 the converted layout, so any read/write will have to be done
3908 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3910 if (offset
+ len
> sizeof (siginfo
))
3911 len
= sizeof (siginfo
) - offset
;
3913 if (readbuf
!= NULL
)
3914 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3917 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3919 /* Convert back to ptrace layout before flushing it out. */
3920 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3923 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3925 return TARGET_XFER_E_IO
;
3929 return TARGET_XFER_OK
;
3932 static enum target_xfer_status
3933 linux_nat_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3934 const char *annex
, gdb_byte
*readbuf
,
3935 const gdb_byte
*writebuf
,
3936 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3938 struct cleanup
*old_chain
;
3939 enum target_xfer_status xfer
;
3941 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3942 return linux_xfer_siginfo (ops
, object
, annex
, readbuf
, writebuf
,
3943 offset
, len
, xfered_len
);
3945 /* The target is connected but no live inferior is selected. Pass
3946 this request down to a lower stratum (e.g., the executable
3948 if (object
== TARGET_OBJECT_MEMORY
&& ptid_equal (inferior_ptid
, null_ptid
))
3949 return TARGET_XFER_EOF
;
3951 old_chain
= save_inferior_ptid ();
3953 if (ptid_lwp_p (inferior_ptid
))
3954 inferior_ptid
= pid_to_ptid (ptid_get_lwp (inferior_ptid
));
3956 xfer
= linux_ops
->to_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
3957 offset
, len
, xfered_len
);
3959 do_cleanups (old_chain
);
3964 linux_thread_alive (ptid_t ptid
)
3968 gdb_assert (ptid_lwp_p (ptid
));
3970 /* Send signal 0 instead of anything ptrace, because ptracing a
3971 running thread errors out claiming that the thread doesn't
3973 err
= kill_lwp (ptid_get_lwp (ptid
), 0);
3975 if (debug_linux_nat
)
3976 fprintf_unfiltered (gdb_stdlog
,
3977 "LLTA: KILL(SIG0) %s (%s)\n",
3978 target_pid_to_str (ptid
),
3979 err
? safe_strerror (tmp_errno
) : "OK");
3988 linux_nat_thread_alive (struct target_ops
*ops
, ptid_t ptid
)
3990 return linux_thread_alive (ptid
);
3994 linux_nat_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
3996 static char buf
[64];
3998 if (ptid_lwp_p (ptid
)
3999 && (ptid_get_pid (ptid
) != ptid_get_lwp (ptid
)
4000 || num_lwps (ptid_get_pid (ptid
)) > 1))
4002 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid_get_lwp (ptid
));
4006 return normal_pid_to_str (ptid
);
4010 linux_nat_thread_name (struct target_ops
*self
, struct thread_info
*thr
)
4012 int pid
= ptid_get_pid (thr
->ptid
);
4013 long lwp
= ptid_get_lwp (thr
->ptid
);
4014 #define FORMAT "/proc/%d/task/%ld/comm"
4015 char buf
[sizeof (FORMAT
) + 30];
4017 char *result
= NULL
;
4019 snprintf (buf
, sizeof (buf
), FORMAT
, pid
, lwp
);
4020 comm_file
= gdb_fopen_cloexec (buf
, "r");
4023 /* Not exported by the kernel, so we define it here. */
4025 static char line
[COMM_LEN
+ 1];
4027 if (fgets (line
, sizeof (line
), comm_file
))
4029 char *nl
= strchr (line
, '\n');
4046 /* Accepts an integer PID; Returns a string representing a file that
4047 can be opened to get the symbols for the child process. */
4050 linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
)
4052 static char buf
[PATH_MAX
];
4053 char name
[PATH_MAX
];
4055 xsnprintf (name
, PATH_MAX
, "/proc/%d/exe", pid
);
4056 memset (buf
, 0, PATH_MAX
);
4057 if (readlink (name
, buf
, PATH_MAX
- 1) <= 0)
4063 /* Records the thread's register state for the corefile note
4067 linux_nat_collect_thread_registers (const struct regcache
*regcache
,
4068 ptid_t ptid
, bfd
*obfd
,
4069 char *note_data
, int *note_size
,
4070 enum gdb_signal stop_signal
)
4072 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
4073 const struct regset
*regset
;
4075 gdb_gregset_t gregs
;
4076 gdb_fpregset_t fpregs
;
4078 core_regset_p
= gdbarch_regset_from_core_section_p (gdbarch
);
4081 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg",
4083 != NULL
&& regset
->collect_regset
!= NULL
)
4084 regset
->collect_regset (regset
, regcache
, -1, &gregs
, sizeof (gregs
));
4086 fill_gregset (regcache
, &gregs
, -1);
4088 note_data
= (char *) elfcore_write_prstatus
4089 (obfd
, note_data
, note_size
, ptid_get_lwp (ptid
),
4090 gdb_signal_to_host (stop_signal
), &gregs
);
4093 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg2",
4095 != NULL
&& regset
->collect_regset
!= NULL
)
4096 regset
->collect_regset (regset
, regcache
, -1, &fpregs
, sizeof (fpregs
));
4098 fill_fpregset (regcache
, &fpregs
, -1);
4100 note_data
= (char *) elfcore_write_prfpreg (obfd
, note_data
, note_size
,
4101 &fpregs
, sizeof (fpregs
));
4106 /* Fills the "to_make_corefile_note" target vector. Builds the note
4107 section for a corefile, and returns it in a malloc buffer. */
4110 linux_nat_make_corefile_notes (struct target_ops
*self
,
4111 bfd
*obfd
, int *note_size
)
4113 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4114 converted to gdbarch_core_regset_sections, this function can go away. */
4115 return linux_make_corefile_notes (target_gdbarch (), obfd
, note_size
,
4116 linux_nat_collect_thread_registers
);
4119 /* Implement the to_xfer_partial interface for memory reads using the /proc
4120 filesystem. Because we can use a single read() call for /proc, this
4121 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4122 but it doesn't support writes. */
4124 static enum target_xfer_status
4125 linux_proc_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4126 const char *annex
, gdb_byte
*readbuf
,
4127 const gdb_byte
*writebuf
,
4128 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
4134 if (object
!= TARGET_OBJECT_MEMORY
|| !readbuf
)
4137 /* Don't bother for one word. */
4138 if (len
< 3 * sizeof (long))
4139 return TARGET_XFER_EOF
;
4141 /* We could keep this file open and cache it - possibly one per
4142 thread. That requires some juggling, but is even faster. */
4143 xsnprintf (filename
, sizeof filename
, "/proc/%d/mem",
4144 ptid_get_pid (inferior_ptid
));
4145 fd
= gdb_open_cloexec (filename
, O_RDONLY
| O_LARGEFILE
, 0);
4147 return TARGET_XFER_EOF
;
4149 /* If pread64 is available, use it. It's faster if the kernel
4150 supports it (only one syscall), and it's 64-bit safe even on
4151 32-bit platforms (for instance, SPARC debugging a SPARC64
4154 if (pread64 (fd
, readbuf
, len
, offset
) != len
)
4156 if (lseek (fd
, offset
, SEEK_SET
) == -1 || read (fd
, readbuf
, len
) != len
)
4165 return TARGET_XFER_EOF
;
4169 return TARGET_XFER_OK
;
4174 /* Enumerate spufs IDs for process PID. */
4176 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
4178 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
4180 LONGEST written
= 0;
4183 struct dirent
*entry
;
4185 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
4186 dir
= opendir (path
);
4191 while ((entry
= readdir (dir
)) != NULL
)
4197 fd
= atoi (entry
->d_name
);
4201 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
4202 if (stat (path
, &st
) != 0)
4204 if (!S_ISDIR (st
.st_mode
))
4207 if (statfs (path
, &stfs
) != 0)
4209 if (stfs
.f_type
!= SPUFS_MAGIC
)
4212 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
4214 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
4224 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4225 object type, using the /proc file system. */
4227 static enum target_xfer_status
4228 linux_proc_xfer_spu (struct target_ops
*ops
, enum target_object object
,
4229 const char *annex
, gdb_byte
*readbuf
,
4230 const gdb_byte
*writebuf
,
4231 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
4236 int pid
= ptid_get_pid (inferior_ptid
);
4241 return TARGET_XFER_E_IO
;
4244 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4247 return TARGET_XFER_E_IO
;
4249 return TARGET_XFER_EOF
;
4252 *xfered_len
= (ULONGEST
) l
;
4253 return TARGET_XFER_OK
;
4258 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4259 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4261 return TARGET_XFER_E_IO
;
4264 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4267 return TARGET_XFER_EOF
;
4271 ret
= write (fd
, writebuf
, (size_t) len
);
4273 ret
= read (fd
, readbuf
, (size_t) len
);
4278 return TARGET_XFER_E_IO
;
4280 return TARGET_XFER_EOF
;
4283 *xfered_len
= (ULONGEST
) ret
;
4284 return TARGET_XFER_OK
;
4289 /* Parse LINE as a signal set and add its set bits to SIGS. */
4292 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4294 int len
= strlen (line
) - 1;
4298 if (line
[len
] != '\n')
4299 error (_("Could not parse signal set: %s"), line
);
4307 if (*p
>= '0' && *p
<= '9')
4309 else if (*p
>= 'a' && *p
<= 'f')
4310 digit
= *p
- 'a' + 10;
4312 error (_("Could not parse signal set: %s"), line
);
4317 sigaddset (sigs
, signum
+ 1);
4319 sigaddset (sigs
, signum
+ 2);
4321 sigaddset (sigs
, signum
+ 3);
4323 sigaddset (sigs
, signum
+ 4);
4329 /* Find process PID's pending signals from /proc/pid/status and set
4333 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4334 sigset_t
*blocked
, sigset_t
*ignored
)
4337 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4338 struct cleanup
*cleanup
;
4340 sigemptyset (pending
);
4341 sigemptyset (blocked
);
4342 sigemptyset (ignored
);
4343 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4344 procfile
= gdb_fopen_cloexec (fname
, "r");
4345 if (procfile
== NULL
)
4346 error (_("Could not open %s"), fname
);
4347 cleanup
= make_cleanup_fclose (procfile
);
4349 while (fgets (buffer
, PATH_MAX
, procfile
) != NULL
)
4351 /* Normal queued signals are on the SigPnd line in the status
4352 file. However, 2.6 kernels also have a "shared" pending
4353 queue for delivering signals to a thread group, so check for
4356 Unfortunately some Red Hat kernels include the shared pending
4357 queue but not the ShdPnd status field. */
4359 if (strncmp (buffer
, "SigPnd:\t", 8) == 0)
4360 add_line_to_sigset (buffer
+ 8, pending
);
4361 else if (strncmp (buffer
, "ShdPnd:\t", 8) == 0)
4362 add_line_to_sigset (buffer
+ 8, pending
);
4363 else if (strncmp (buffer
, "SigBlk:\t", 8) == 0)
4364 add_line_to_sigset (buffer
+ 8, blocked
);
4365 else if (strncmp (buffer
, "SigIgn:\t", 8) == 0)
4366 add_line_to_sigset (buffer
+ 8, ignored
);
4369 do_cleanups (cleanup
);
4372 static enum target_xfer_status
4373 linux_nat_xfer_osdata (struct target_ops
*ops
, enum target_object object
,
4374 const char *annex
, gdb_byte
*readbuf
,
4375 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4376 ULONGEST
*xfered_len
)
4378 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4380 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4381 if (*xfered_len
== 0)
4382 return TARGET_XFER_EOF
;
4384 return TARGET_XFER_OK
;
4387 static enum target_xfer_status
4388 linux_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4389 const char *annex
, gdb_byte
*readbuf
,
4390 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4391 ULONGEST
*xfered_len
)
4393 enum target_xfer_status xfer
;
4395 if (object
== TARGET_OBJECT_AUXV
)
4396 return memory_xfer_auxv (ops
, object
, annex
, readbuf
, writebuf
,
4397 offset
, len
, xfered_len
);
4399 if (object
== TARGET_OBJECT_OSDATA
)
4400 return linux_nat_xfer_osdata (ops
, object
, annex
, readbuf
, writebuf
,
4401 offset
, len
, xfered_len
);
4403 if (object
== TARGET_OBJECT_SPU
)
4404 return linux_proc_xfer_spu (ops
, object
, annex
, readbuf
, writebuf
,
4405 offset
, len
, xfered_len
);
4407 /* GDB calculates all the addresses in possibly larget width of the address.
4408 Address width needs to be masked before its final use - either by
4409 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4411 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4413 if (object
== TARGET_OBJECT_MEMORY
)
4415 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
4417 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
4418 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
4421 xfer
= linux_proc_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4422 offset
, len
, xfered_len
);
4423 if (xfer
!= TARGET_XFER_EOF
)
4426 return super_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4427 offset
, len
, xfered_len
);
4431 cleanup_target_stop (void *arg
)
4433 ptid_t
*ptid
= (ptid_t
*) arg
;
4435 gdb_assert (arg
!= NULL
);
4438 target_resume (*ptid
, 0, GDB_SIGNAL_0
);
4441 static VEC(static_tracepoint_marker_p
) *
4442 linux_child_static_tracepoint_markers_by_strid (struct target_ops
*self
,
4445 char s
[IPA_CMD_BUF_SIZE
];
4446 struct cleanup
*old_chain
;
4447 int pid
= ptid_get_pid (inferior_ptid
);
4448 VEC(static_tracepoint_marker_p
) *markers
= NULL
;
4449 struct static_tracepoint_marker
*marker
= NULL
;
4451 ptid_t ptid
= ptid_build (pid
, 0, 0);
4456 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4457 s
[sizeof ("qTfSTM")] = 0;
4459 agent_run_command (pid
, s
, strlen (s
) + 1);
4461 old_chain
= make_cleanup (free_current_marker
, &marker
);
4462 make_cleanup (cleanup_target_stop
, &ptid
);
4467 marker
= XCNEW (struct static_tracepoint_marker
);
4471 parse_static_tracepoint_marker_definition (p
, &p
, marker
);
4473 if (strid
== NULL
|| strcmp (strid
, marker
->str_id
) == 0)
4475 VEC_safe_push (static_tracepoint_marker_p
,
4481 release_static_tracepoint_marker (marker
);
4482 memset (marker
, 0, sizeof (*marker
));
4485 while (*p
++ == ','); /* comma-separated list */
4487 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4488 s
[sizeof ("qTsSTM")] = 0;
4489 agent_run_command (pid
, s
, strlen (s
) + 1);
4493 do_cleanups (old_chain
);
4498 /* Create a prototype generic GNU/Linux target. The client can override
4499 it with local methods. */
4502 linux_target_install_ops (struct target_ops
*t
)
4504 t
->to_insert_fork_catchpoint
= linux_child_insert_fork_catchpoint
;
4505 t
->to_remove_fork_catchpoint
= linux_child_remove_fork_catchpoint
;
4506 t
->to_insert_vfork_catchpoint
= linux_child_insert_vfork_catchpoint
;
4507 t
->to_remove_vfork_catchpoint
= linux_child_remove_vfork_catchpoint
;
4508 t
->to_insert_exec_catchpoint
= linux_child_insert_exec_catchpoint
;
4509 t
->to_remove_exec_catchpoint
= linux_child_remove_exec_catchpoint
;
4510 t
->to_set_syscall_catchpoint
= linux_child_set_syscall_catchpoint
;
4511 t
->to_pid_to_exec_file
= linux_child_pid_to_exec_file
;
4512 t
->to_post_startup_inferior
= linux_child_post_startup_inferior
;
4513 t
->to_post_attach
= linux_child_post_attach
;
4514 t
->to_follow_fork
= linux_child_follow_fork
;
4515 t
->to_make_corefile_notes
= linux_nat_make_corefile_notes
;
4517 super_xfer_partial
= t
->to_xfer_partial
;
4518 t
->to_xfer_partial
= linux_xfer_partial
;
4520 t
->to_static_tracepoint_markers_by_strid
4521 = linux_child_static_tracepoint_markers_by_strid
;
4527 struct target_ops
*t
;
4529 t
= inf_ptrace_target ();
4530 linux_target_install_ops (t
);
4536 linux_trad_target (CORE_ADDR (*register_u_offset
)(struct gdbarch
*, int, int))
4538 struct target_ops
*t
;
4540 t
= inf_ptrace_trad_target (register_u_offset
);
4541 linux_target_install_ops (t
);
4546 /* target_is_async_p implementation. */
4549 linux_nat_is_async_p (struct target_ops
*ops
)
4551 /* NOTE: palves 2008-03-21: We're only async when the user requests
4552 it explicitly with the "set target-async" command.
4553 Someday, linux will always be async. */
4554 return target_async_permitted
;
4557 /* target_can_async_p implementation. */
4560 linux_nat_can_async_p (struct target_ops
*ops
)
4562 /* NOTE: palves 2008-03-21: We're only async when the user requests
4563 it explicitly with the "set target-async" command.
4564 Someday, linux will always be async. */
4565 return target_async_permitted
;
4569 linux_nat_supports_non_stop (struct target_ops
*self
)
4574 /* True if we want to support multi-process. To be removed when GDB
4575 supports multi-exec. */
4577 int linux_multi_process
= 1;
4580 linux_nat_supports_multi_process (struct target_ops
*self
)
4582 return linux_multi_process
;
4586 linux_nat_supports_disable_randomization (struct target_ops
*self
)
4588 #ifdef HAVE_PERSONALITY
4595 static int async_terminal_is_ours
= 1;
4597 /* target_terminal_inferior implementation.
4599 This is a wrapper around child_terminal_inferior to add async support. */
4602 linux_nat_terminal_inferior (struct target_ops
*self
)
4604 if (!target_is_async_p ())
4606 /* Async mode is disabled. */
4607 child_terminal_inferior (self
);
4611 child_terminal_inferior (self
);
4613 /* Calls to target_terminal_*() are meant to be idempotent. */
4614 if (!async_terminal_is_ours
)
4617 delete_file_handler (input_fd
);
4618 async_terminal_is_ours
= 0;
4622 /* target_terminal_ours implementation.
4624 This is a wrapper around child_terminal_ours to add async support (and
4625 implement the target_terminal_ours vs target_terminal_ours_for_output
4626 distinction). child_terminal_ours is currently no different than
4627 child_terminal_ours_for_output.
4628 We leave target_terminal_ours_for_output alone, leaving it to
4629 child_terminal_ours_for_output. */
4632 linux_nat_terminal_ours (struct target_ops
*self
)
4634 if (!target_is_async_p ())
4636 /* Async mode is disabled. */
4637 child_terminal_ours (self
);
4641 /* GDB should never give the terminal to the inferior if the
4642 inferior is running in the background (run&, continue&, etc.),
4643 but claiming it sure should. */
4644 child_terminal_ours (self
);
4646 if (async_terminal_is_ours
)
4649 clear_sigint_trap ();
4650 add_file_handler (input_fd
, stdin_event_handler
, 0);
4651 async_terminal_is_ours
= 1;
4654 static void (*async_client_callback
) (enum inferior_event_type event_type
,
4656 static void *async_client_context
;
4658 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4659 so we notice when any child changes state, and notify the
4660 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4661 above to wait for the arrival of a SIGCHLD. */
4664 sigchld_handler (int signo
)
4666 int old_errno
= errno
;
4668 if (debug_linux_nat
)
4669 ui_file_write_async_safe (gdb_stdlog
,
4670 "sigchld\n", sizeof ("sigchld\n") - 1);
4672 if (signo
== SIGCHLD
4673 && linux_nat_event_pipe
[0] != -1)
4674 async_file_mark (); /* Let the event loop know that there are
4675 events to handle. */
4680 /* Callback registered with the target events file descriptor. */
4683 handle_target_event (int error
, gdb_client_data client_data
)
4685 (*async_client_callback
) (INF_REG_EVENT
, async_client_context
);
4688 /* Create/destroy the target events pipe. Returns previous state. */
4691 linux_async_pipe (int enable
)
4693 int previous
= (linux_nat_event_pipe
[0] != -1);
4695 if (previous
!= enable
)
4699 /* Block child signals while we create/destroy the pipe, as
4700 their handler writes to it. */
4701 block_child_signals (&prev_mask
);
4705 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4706 internal_error (__FILE__
, __LINE__
,
4707 "creating event pipe failed.");
4709 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4710 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4714 close (linux_nat_event_pipe
[0]);
4715 close (linux_nat_event_pipe
[1]);
4716 linux_nat_event_pipe
[0] = -1;
4717 linux_nat_event_pipe
[1] = -1;
4720 restore_child_signals_mask (&prev_mask
);
4726 /* target_async implementation. */
4729 linux_nat_async (struct target_ops
*ops
,
4730 void (*callback
) (enum inferior_event_type event_type
,
4734 if (callback
!= NULL
)
4736 async_client_callback
= callback
;
4737 async_client_context
= context
;
4738 if (!linux_async_pipe (1))
4740 add_file_handler (linux_nat_event_pipe
[0],
4741 handle_target_event
, NULL
);
4742 /* There may be pending events to handle. Tell the event loop
4749 async_client_callback
= callback
;
4750 async_client_context
= context
;
4751 delete_file_handler (linux_nat_event_pipe
[0]);
4752 linux_async_pipe (0);
4757 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4761 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4765 if (debug_linux_nat
)
4766 fprintf_unfiltered (gdb_stdlog
,
4767 "LNSL: running -> suspending %s\n",
4768 target_pid_to_str (lwp
->ptid
));
4771 if (lwp
->last_resume_kind
== resume_stop
)
4773 if (debug_linux_nat
)
4774 fprintf_unfiltered (gdb_stdlog
,
4775 "linux-nat: already stopping LWP %ld at "
4777 ptid_get_lwp (lwp
->ptid
));
4781 stop_callback (lwp
, NULL
);
4782 lwp
->last_resume_kind
= resume_stop
;
4786 /* Already known to be stopped; do nothing. */
4788 if (debug_linux_nat
)
4790 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4791 fprintf_unfiltered (gdb_stdlog
,
4792 "LNSL: already stopped/stop_requested %s\n",
4793 target_pid_to_str (lwp
->ptid
));
4795 fprintf_unfiltered (gdb_stdlog
,
4796 "LNSL: already stopped/no "
4797 "stop_requested yet %s\n",
4798 target_pid_to_str (lwp
->ptid
));
4805 linux_nat_stop (struct target_ops
*self
, ptid_t ptid
)
4808 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4810 linux_ops
->to_stop (linux_ops
, ptid
);
4814 linux_nat_close (struct target_ops
*self
)
4816 /* Unregister from the event loop. */
4817 if (linux_nat_is_async_p (NULL
))
4818 linux_nat_async (NULL
, NULL
, 0);
4820 if (linux_ops
->to_close
)
4821 linux_ops
->to_close (linux_ops
);
4826 /* When requests are passed down from the linux-nat layer to the
4827 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4828 used. The address space pointer is stored in the inferior object,
4829 but the common code that is passed such ptid can't tell whether
4830 lwpid is a "main" process id or not (it assumes so). We reverse
4831 look up the "main" process id from the lwp here. */
4833 static struct address_space
*
4834 linux_nat_thread_address_space (struct target_ops
*t
, ptid_t ptid
)
4836 struct lwp_info
*lwp
;
4837 struct inferior
*inf
;
4840 pid
= ptid_get_lwp (ptid
);
4841 if (ptid_get_lwp (ptid
) == 0)
4843 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4845 lwp
= find_lwp_pid (ptid
);
4846 pid
= ptid_get_pid (lwp
->ptid
);
4850 /* A (pid,lwpid,0) ptid. */
4851 pid
= ptid_get_pid (ptid
);
4854 inf
= find_inferior_pid (pid
);
4855 gdb_assert (inf
!= NULL
);
4859 /* Return the cached value of the processor core for thread PTID. */
4862 linux_nat_core_of_thread (struct target_ops
*ops
, ptid_t ptid
)
4864 struct lwp_info
*info
= find_lwp_pid (ptid
);
4872 linux_nat_add_target (struct target_ops
*t
)
4874 /* Save the provided single-threaded target. We save this in a separate
4875 variable because another target we've inherited from (e.g. inf-ptrace)
4876 may have saved a pointer to T; we want to use it for the final
4877 process stratum target. */
4878 linux_ops_saved
= *t
;
4879 linux_ops
= &linux_ops_saved
;
4881 /* Override some methods for multithreading. */
4882 t
->to_create_inferior
= linux_nat_create_inferior
;
4883 t
->to_attach
= linux_nat_attach
;
4884 t
->to_detach
= linux_nat_detach
;
4885 t
->to_resume
= linux_nat_resume
;
4886 t
->to_wait
= linux_nat_wait
;
4887 t
->to_pass_signals
= linux_nat_pass_signals
;
4888 t
->to_xfer_partial
= linux_nat_xfer_partial
;
4889 t
->to_kill
= linux_nat_kill
;
4890 t
->to_mourn_inferior
= linux_nat_mourn_inferior
;
4891 t
->to_thread_alive
= linux_nat_thread_alive
;
4892 t
->to_pid_to_str
= linux_nat_pid_to_str
;
4893 t
->to_thread_name
= linux_nat_thread_name
;
4894 t
->to_has_thread_control
= tc_schedlock
;
4895 t
->to_thread_address_space
= linux_nat_thread_address_space
;
4896 t
->to_stopped_by_watchpoint
= linux_nat_stopped_by_watchpoint
;
4897 t
->to_stopped_data_address
= linux_nat_stopped_data_address
;
4899 t
->to_can_async_p
= linux_nat_can_async_p
;
4900 t
->to_is_async_p
= linux_nat_is_async_p
;
4901 t
->to_supports_non_stop
= linux_nat_supports_non_stop
;
4902 t
->to_async
= linux_nat_async
;
4903 t
->to_terminal_inferior
= linux_nat_terminal_inferior
;
4904 t
->to_terminal_ours
= linux_nat_terminal_ours
;
4906 super_close
= t
->to_close
;
4907 t
->to_close
= linux_nat_close
;
4909 /* Methods for non-stop support. */
4910 t
->to_stop
= linux_nat_stop
;
4912 t
->to_supports_multi_process
= linux_nat_supports_multi_process
;
4914 t
->to_supports_disable_randomization
4915 = linux_nat_supports_disable_randomization
;
4917 t
->to_core_of_thread
= linux_nat_core_of_thread
;
4919 /* We don't change the stratum; this target will sit at
4920 process_stratum and thread_db will set at thread_stratum. This
4921 is a little strange, since this is a multi-threaded-capable
4922 target, but we want to be on the stack below thread_db, and we
4923 also want to be used for single-threaded processes. */
4928 /* Register a method to call whenever a new thread is attached. */
4930 linux_nat_set_new_thread (struct target_ops
*t
,
4931 void (*new_thread
) (struct lwp_info
*))
4933 /* Save the pointer. We only support a single registered instance
4934 of the GNU/Linux native target, so we do not need to map this to
4936 linux_nat_new_thread
= new_thread
;
4939 /* See declaration in linux-nat.h. */
4942 linux_nat_set_new_fork (struct target_ops
*t
,
4943 linux_nat_new_fork_ftype
*new_fork
)
4945 /* Save the pointer. */
4946 linux_nat_new_fork
= new_fork
;
4949 /* See declaration in linux-nat.h. */
4952 linux_nat_set_forget_process (struct target_ops
*t
,
4953 linux_nat_forget_process_ftype
*fn
)
4955 /* Save the pointer. */
4956 linux_nat_forget_process_hook
= fn
;
4959 /* See declaration in linux-nat.h. */
4962 linux_nat_forget_process (pid_t pid
)
4964 if (linux_nat_forget_process_hook
!= NULL
)
4965 linux_nat_forget_process_hook (pid
);
4968 /* Register a method that converts a siginfo object between the layout
4969 that ptrace returns, and the layout in the architecture of the
4972 linux_nat_set_siginfo_fixup (struct target_ops
*t
,
4973 int (*siginfo_fixup
) (siginfo_t
*,
4977 /* Save the pointer. */
4978 linux_nat_siginfo_fixup
= siginfo_fixup
;
4981 /* Register a method to call prior to resuming a thread. */
4984 linux_nat_set_prepare_to_resume (struct target_ops
*t
,
4985 void (*prepare_to_resume
) (struct lwp_info
*))
4987 /* Save the pointer. */
4988 linux_nat_prepare_to_resume
= prepare_to_resume
;
4991 /* See linux-nat.h. */
4994 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4998 pid
= ptid_get_lwp (ptid
);
5000 pid
= ptid_get_pid (ptid
);
5003 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
5006 memset (siginfo
, 0, sizeof (*siginfo
));
5012 /* Provide a prototype to silence -Wmissing-prototypes. */
5013 extern initialize_file_ftype _initialize_linux_nat
;
5016 _initialize_linux_nat (void)
5018 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
5019 &debug_linux_nat
, _("\
5020 Set debugging of GNU/Linux lwp module."), _("\
5021 Show debugging of GNU/Linux lwp module."), _("\
5022 Enables printf debugging output."),
5024 show_debug_linux_nat
,
5025 &setdebuglist
, &showdebuglist
);
5027 /* Save this mask as the default. */
5028 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
5030 /* Install a SIGCHLD handler. */
5031 sigchld_action
.sa_handler
= sigchld_handler
;
5032 sigemptyset (&sigchld_action
.sa_mask
);
5033 sigchld_action
.sa_flags
= SA_RESTART
;
5035 /* Make it the default. */
5036 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
5038 /* Make sure we don't block SIGCHLD during a sigsuspend. */
5039 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
5040 sigdelset (&suspend_mask
, SIGCHLD
);
5042 sigemptyset (&blocked_mask
);
5044 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
5045 support read-only process state. */
5046 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
5047 | PTRACE_O_TRACEVFORKDONE
5048 | PTRACE_O_TRACEVFORK
5049 | PTRACE_O_TRACEFORK
5050 | PTRACE_O_TRACEEXEC
);
5054 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
5055 the GNU/Linux Threads library and therefore doesn't really belong
5058 /* Read variable NAME in the target and return its value if found.
5059 Otherwise return zero. It is assumed that the type of the variable
5063 get_signo (const char *name
)
5065 struct bound_minimal_symbol ms
;
5068 ms
= lookup_minimal_symbol (name
, NULL
, NULL
);
5069 if (ms
.minsym
== NULL
)
5072 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms
), (gdb_byte
*) &signo
,
5073 sizeof (signo
)) != 0)
5079 /* Return the set of signals used by the threads library in *SET. */
5082 lin_thread_get_thread_signals (sigset_t
*set
)
5084 struct sigaction action
;
5085 int restart
, cancel
;
5087 sigemptyset (&blocked_mask
);
5090 restart
= get_signo ("__pthread_sig_restart");
5091 cancel
= get_signo ("__pthread_sig_cancel");
5093 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5094 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5095 not provide any way for the debugger to query the signal numbers -
5096 fortunately they don't change! */
5099 restart
= __SIGRTMIN
;
5102 cancel
= __SIGRTMIN
+ 1;
5104 sigaddset (set
, restart
);
5105 sigaddset (set
, cancel
);
5107 /* The GNU/Linux Threads library makes terminating threads send a
5108 special "cancel" signal instead of SIGCHLD. Make sure we catch
5109 those (to prevent them from terminating GDB itself, which is
5110 likely to be their default action) and treat them the same way as
5113 action
.sa_handler
= sigchld_handler
;
5114 sigemptyset (&action
.sa_mask
);
5115 action
.sa_flags
= SA_RESTART
;
5116 sigaction (cancel
, &action
, NULL
);
5118 /* We block the "cancel" signal throughout this code ... */
5119 sigaddset (&blocked_mask
, cancel
);
5120 sigprocmask (SIG_BLOCK
, &blocked_mask
, NULL
);
5122 /* ... except during a sigsuspend. */
5123 sigdelset (&suspend_mask
, cancel
);