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/>. */
23 #include "nat/linux-nat.h"
24 #include "nat/linux-waitpid.h"
27 #include "gdb_assert.h"
28 #ifdef HAVE_TKILL_SYSCALL
30 #include <sys/syscall.h>
32 #include <sys/ptrace.h>
33 #include "linux-nat.h"
34 #include "linux-ptrace.h"
35 #include "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 "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 static unsigned int debug_linux_nat
;
206 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
207 struct cmd_list_element
*c
, const char *value
)
209 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
213 struct simple_pid_list
217 struct simple_pid_list
*next
;
219 struct simple_pid_list
*stopped_pids
;
221 /* Async mode support. */
223 /* The read/write ends of the pipe registered as waitable file in the
225 static int linux_nat_event_pipe
[2] = { -1, -1 };
227 /* Flush the event pipe. */
230 async_file_flush (void)
237 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
239 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
242 /* Put something (anything, doesn't matter what, or how much) in event
243 pipe, so that the select/poll in the event-loop realizes we have
244 something to process. */
247 async_file_mark (void)
251 /* It doesn't really matter what the pipe contains, as long we end
252 up with something in it. Might as well flush the previous
258 ret
= write (linux_nat_event_pipe
[1], "+", 1);
260 while (ret
== -1 && errno
== EINTR
);
262 /* Ignore EAGAIN. If the pipe is full, the event loop will already
263 be awakened anyway. */
266 static int kill_lwp (int lwpid
, int signo
);
268 static int stop_callback (struct lwp_info
*lp
, void *data
);
270 static void block_child_signals (sigset_t
*prev_mask
);
271 static void restore_child_signals_mask (sigset_t
*prev_mask
);
274 static struct lwp_info
*add_lwp (ptid_t ptid
);
275 static void purge_lwp_list (int pid
);
276 static void delete_lwp (ptid_t ptid
);
277 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
280 /* Trivial list manipulation functions to keep track of a list of
281 new stopped processes. */
283 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
285 struct simple_pid_list
*new_pid
= xmalloc (sizeof (struct simple_pid_list
));
288 new_pid
->status
= status
;
289 new_pid
->next
= *listp
;
294 in_pid_list_p (struct simple_pid_list
*list
, int pid
)
296 struct simple_pid_list
*p
;
298 for (p
= list
; p
!= NULL
; p
= p
->next
)
305 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
307 struct simple_pid_list
**p
;
309 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
310 if ((*p
)->pid
== pid
)
312 struct simple_pid_list
*next
= (*p
)->next
;
314 *statusp
= (*p
)->status
;
322 /* Initialize ptrace warnings and check for supported ptrace
323 features given PID. */
326 linux_init_ptrace (pid_t pid
)
328 linux_enable_event_reporting (pid
);
329 linux_ptrace_init_warnings ();
333 linux_child_post_attach (struct target_ops
*self
, int pid
)
335 linux_init_ptrace (pid
);
339 linux_child_post_startup_inferior (struct target_ops
*self
, ptid_t ptid
)
341 linux_init_ptrace (ptid_get_pid (ptid
));
344 /* Return the number of known LWPs in the tgid given by PID. */
352 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
353 if (ptid_get_pid (lp
->ptid
) == pid
)
359 /* Call delete_lwp with prototype compatible for make_cleanup. */
362 delete_lwp_cleanup (void *lp_voidp
)
364 struct lwp_info
*lp
= lp_voidp
;
366 delete_lwp (lp
->ptid
);
370 linux_child_follow_fork (struct target_ops
*ops
, int follow_child
,
374 int parent_pid
, child_pid
;
376 has_vforked
= (inferior_thread ()->pending_follow
.kind
377 == TARGET_WAITKIND_VFORKED
);
378 parent_pid
= ptid_get_lwp (inferior_ptid
);
380 parent_pid
= ptid_get_pid (inferior_ptid
);
382 = ptid_get_pid (inferior_thread ()->pending_follow
.value
.related_pid
);
385 && !non_stop
/* Non-stop always resumes both branches. */
386 && (!target_is_async_p () || sync_execution
)
387 && !(follow_child
|| detach_fork
|| sched_multi
))
389 /* The parent stays blocked inside the vfork syscall until the
390 child execs or exits. If we don't let the child run, then
391 the parent stays blocked. If we're telling the parent to run
392 in the foreground, the user will not be able to ctrl-c to get
393 back the terminal, effectively hanging the debug session. */
394 fprintf_filtered (gdb_stderr
, _("\
395 Can not resume the parent process over vfork in the foreground while\n\
396 holding the child stopped. Try \"set detach-on-fork\" or \
397 \"set schedule-multiple\".\n"));
398 /* FIXME output string > 80 columns. */
404 struct lwp_info
*child_lp
= NULL
;
406 /* We're already attached to the parent, by default. */
408 /* Detach new forked process? */
411 struct cleanup
*old_chain
;
413 /* Before detaching from the child, remove all breakpoints
414 from it. If we forked, then this has already been taken
415 care of by infrun.c. If we vforked however, any
416 breakpoint inserted in the parent is visible in the
417 child, even those added while stopped in a vfork
418 catchpoint. This will remove the breakpoints from the
419 parent also, but they'll be reinserted below. */
422 /* keep breakpoints list in sync. */
423 remove_breakpoints_pid (ptid_get_pid (inferior_ptid
));
426 if (info_verbose
|| debug_linux_nat
)
428 target_terminal_ours ();
429 fprintf_filtered (gdb_stdlog
,
430 "Detaching after fork from "
431 "child process %d.\n",
435 old_chain
= save_inferior_ptid ();
436 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
438 child_lp
= add_lwp (inferior_ptid
);
439 child_lp
->stopped
= 1;
440 child_lp
->last_resume_kind
= resume_stop
;
441 make_cleanup (delete_lwp_cleanup
, child_lp
);
443 if (linux_nat_prepare_to_resume
!= NULL
)
444 linux_nat_prepare_to_resume (child_lp
);
445 ptrace (PTRACE_DETACH
, child_pid
, 0, 0);
447 do_cleanups (old_chain
);
451 struct inferior
*parent_inf
, *child_inf
;
452 struct cleanup
*old_chain
;
454 /* Add process to GDB's tables. */
455 child_inf
= add_inferior (child_pid
);
457 parent_inf
= current_inferior ();
458 child_inf
->attach_flag
= parent_inf
->attach_flag
;
459 copy_terminal_info (child_inf
, parent_inf
);
460 child_inf
->gdbarch
= parent_inf
->gdbarch
;
461 copy_inferior_target_desc_info (child_inf
, parent_inf
);
463 old_chain
= save_inferior_ptid ();
464 save_current_program_space ();
466 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
467 add_thread (inferior_ptid
);
468 child_lp
= add_lwp (inferior_ptid
);
469 child_lp
->stopped
= 1;
470 child_lp
->last_resume_kind
= resume_stop
;
471 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
473 /* If this is a vfork child, then the address-space is
474 shared with the parent. */
477 child_inf
->pspace
= parent_inf
->pspace
;
478 child_inf
->aspace
= parent_inf
->aspace
;
480 /* The parent will be frozen until the child is done
481 with the shared region. Keep track of the
483 child_inf
->vfork_parent
= parent_inf
;
484 child_inf
->pending_detach
= 0;
485 parent_inf
->vfork_child
= child_inf
;
486 parent_inf
->pending_detach
= 0;
490 child_inf
->aspace
= new_address_space ();
491 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
492 child_inf
->removable
= 1;
493 set_current_program_space (child_inf
->pspace
);
494 clone_program_space (child_inf
->pspace
, parent_inf
->pspace
);
496 /* Let the shared library layer (solib-svr4) learn about
497 this new process, relocate the cloned exec, pull in
498 shared libraries, and install the solib event
499 breakpoint. If a "cloned-VM" event was propagated
500 better throughout the core, this wouldn't be
502 solib_create_inferior_hook (0);
505 /* Let the thread_db layer learn about this new process. */
506 check_for_thread_db ();
508 do_cleanups (old_chain
);
513 struct lwp_info
*parent_lp
;
514 struct inferior
*parent_inf
;
516 parent_inf
= current_inferior ();
518 /* If we detached from the child, then we have to be careful
519 to not insert breakpoints in the parent until the child
520 is done with the shared memory region. However, if we're
521 staying attached to the child, then we can and should
522 insert breakpoints, so that we can debug it. A
523 subsequent child exec or exit is enough to know when does
524 the child stops using the parent's address space. */
525 parent_inf
->waiting_for_vfork_done
= detach_fork
;
526 parent_inf
->pspace
->breakpoints_not_allowed
= detach_fork
;
528 parent_lp
= find_lwp_pid (pid_to_ptid (parent_pid
));
529 gdb_assert (linux_supports_tracefork () >= 0);
531 if (linux_supports_tracevforkdone ())
534 fprintf_unfiltered (gdb_stdlog
,
535 "LCFF: waiting for VFORK_DONE on %d\n",
537 parent_lp
->stopped
= 1;
539 /* We'll handle the VFORK_DONE event like any other
540 event, in target_wait. */
544 /* We can't insert breakpoints until the child has
545 finished with the shared memory region. We need to
546 wait until that happens. Ideal would be to just
548 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
549 - waitpid (parent_pid, &status, __WALL);
550 However, most architectures can't handle a syscall
551 being traced on the way out if it wasn't traced on
554 We might also think to loop, continuing the child
555 until it exits or gets a SIGTRAP. One problem is
556 that the child might call ptrace with PTRACE_TRACEME.
558 There's no simple and reliable way to figure out when
559 the vforked child will be done with its copy of the
560 shared memory. We could step it out of the syscall,
561 two instructions, let it go, and then single-step the
562 parent once. When we have hardware single-step, this
563 would work; with software single-step it could still
564 be made to work but we'd have to be able to insert
565 single-step breakpoints in the child, and we'd have
566 to insert -just- the single-step breakpoint in the
567 parent. Very awkward.
569 In the end, the best we can do is to make sure it
570 runs for a little while. Hopefully it will be out of
571 range of any breakpoints we reinsert. Usually this
572 is only the single-step breakpoint at vfork's return
576 fprintf_unfiltered (gdb_stdlog
,
577 "LCFF: no VFORK_DONE "
578 "support, sleeping a bit\n");
582 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
583 and leave it pending. The next linux_nat_resume call
584 will notice a pending event, and bypasses actually
585 resuming the inferior. */
586 parent_lp
->status
= 0;
587 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
588 parent_lp
->stopped
= 1;
590 /* If we're in async mode, need to tell the event loop
591 there's something here to process. */
592 if (target_can_async_p ())
599 struct inferior
*parent_inf
, *child_inf
;
600 struct lwp_info
*child_lp
;
601 struct program_space
*parent_pspace
;
603 if (info_verbose
|| debug_linux_nat
)
605 target_terminal_ours ();
607 fprintf_filtered (gdb_stdlog
,
608 _("Attaching after process %d "
609 "vfork to child process %d.\n"),
610 parent_pid
, child_pid
);
612 fprintf_filtered (gdb_stdlog
,
613 _("Attaching after process %d "
614 "fork to child process %d.\n"),
615 parent_pid
, child_pid
);
618 /* Add the new inferior first, so that the target_detach below
619 doesn't unpush the target. */
621 child_inf
= add_inferior (child_pid
);
623 parent_inf
= current_inferior ();
624 child_inf
->attach_flag
= parent_inf
->attach_flag
;
625 copy_terminal_info (child_inf
, parent_inf
);
626 child_inf
->gdbarch
= parent_inf
->gdbarch
;
627 copy_inferior_target_desc_info (child_inf
, parent_inf
);
629 parent_pspace
= parent_inf
->pspace
;
631 /* If we're vforking, we want to hold on to the parent until the
632 child exits or execs. At child exec or exit time we can
633 remove the old breakpoints from the parent and detach or
634 resume debugging it. Otherwise, detach the parent now; we'll
635 want to reuse it's program/address spaces, but we can't set
636 them to the child before removing breakpoints from the
637 parent, otherwise, the breakpoints module could decide to
638 remove breakpoints from the wrong process (since they'd be
639 assigned to the same address space). */
643 gdb_assert (child_inf
->vfork_parent
== NULL
);
644 gdb_assert (parent_inf
->vfork_child
== NULL
);
645 child_inf
->vfork_parent
= parent_inf
;
646 child_inf
->pending_detach
= 0;
647 parent_inf
->vfork_child
= child_inf
;
648 parent_inf
->pending_detach
= detach_fork
;
649 parent_inf
->waiting_for_vfork_done
= 0;
651 else if (detach_fork
)
652 target_detach (NULL
, 0);
654 /* Note that the detach above makes PARENT_INF dangling. */
656 /* Add the child thread to the appropriate lists, and switch to
657 this new thread, before cloning the program space, and
658 informing the solib layer about this new process. */
660 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
661 add_thread (inferior_ptid
);
662 child_lp
= add_lwp (inferior_ptid
);
663 child_lp
->stopped
= 1;
664 child_lp
->last_resume_kind
= resume_stop
;
666 /* If this is a vfork child, then the address-space is shared
667 with the parent. If we detached from the parent, then we can
668 reuse the parent's program/address spaces. */
669 if (has_vforked
|| detach_fork
)
671 child_inf
->pspace
= parent_pspace
;
672 child_inf
->aspace
= child_inf
->pspace
->aspace
;
676 child_inf
->aspace
= new_address_space ();
677 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
678 child_inf
->removable
= 1;
679 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
680 set_current_program_space (child_inf
->pspace
);
681 clone_program_space (child_inf
->pspace
, parent_pspace
);
683 /* Let the shared library layer (solib-svr4) learn about
684 this new process, relocate the cloned exec, pull in
685 shared libraries, and install the solib event breakpoint.
686 If a "cloned-VM" event was propagated better throughout
687 the core, this wouldn't be required. */
688 solib_create_inferior_hook (0);
691 /* Let the thread_db layer learn about this new process. */
692 check_for_thread_db ();
700 linux_child_insert_fork_catchpoint (struct target_ops
*self
, int pid
)
702 return !linux_supports_tracefork ();
706 linux_child_remove_fork_catchpoint (struct target_ops
*self
, int pid
)
712 linux_child_insert_vfork_catchpoint (struct target_ops
*self
, int pid
)
714 return !linux_supports_tracefork ();
718 linux_child_remove_vfork_catchpoint (struct target_ops
*self
, int pid
)
724 linux_child_insert_exec_catchpoint (struct target_ops
*self
, int pid
)
726 return !linux_supports_tracefork ();
730 linux_child_remove_exec_catchpoint (struct target_ops
*self
, int pid
)
736 linux_child_set_syscall_catchpoint (struct target_ops
*self
,
737 int pid
, int needed
, int any_count
,
738 int table_size
, int *table
)
740 if (!linux_supports_tracesysgood ())
743 /* On GNU/Linux, we ignore the arguments. It means that we only
744 enable the syscall catchpoints, but do not disable them.
746 Also, we do not use the `table' information because we do not
747 filter system calls here. We let GDB do the logic for us. */
751 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
752 are processes sharing the same VM space. A multi-threaded process
753 is basically a group of such processes. However, such a grouping
754 is almost entirely a user-space issue; the kernel doesn't enforce
755 such a grouping at all (this might change in the future). In
756 general, we'll rely on the threads library (i.e. the GNU/Linux
757 Threads library) to provide such a grouping.
759 It is perfectly well possible to write a multi-threaded application
760 without the assistance of a threads library, by using the clone
761 system call directly. This module should be able to give some
762 rudimentary support for debugging such applications if developers
763 specify the CLONE_PTRACE flag in the clone system call, and are
764 using the Linux kernel 2.4 or above.
766 Note that there are some peculiarities in GNU/Linux that affect
769 - In general one should specify the __WCLONE flag to waitpid in
770 order to make it report events for any of the cloned processes
771 (and leave it out for the initial process). However, if a cloned
772 process has exited the exit status is only reported if the
773 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
774 we cannot use it since GDB must work on older systems too.
776 - When a traced, cloned process exits and is waited for by the
777 debugger, the kernel reassigns it to the original parent and
778 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
779 library doesn't notice this, which leads to the "zombie problem":
780 When debugged a multi-threaded process that spawns a lot of
781 threads will run out of processes, even if the threads exit,
782 because the "zombies" stay around. */
784 /* List of known LWPs. */
785 struct lwp_info
*lwp_list
;
788 /* Original signal mask. */
789 static sigset_t normal_mask
;
791 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
792 _initialize_linux_nat. */
793 static sigset_t suspend_mask
;
795 /* Signals to block to make that sigsuspend work. */
796 static sigset_t blocked_mask
;
798 /* SIGCHLD action. */
799 struct sigaction sigchld_action
;
801 /* Block child signals (SIGCHLD and linux threads signals), and store
802 the previous mask in PREV_MASK. */
805 block_child_signals (sigset_t
*prev_mask
)
807 /* Make sure SIGCHLD is blocked. */
808 if (!sigismember (&blocked_mask
, SIGCHLD
))
809 sigaddset (&blocked_mask
, SIGCHLD
);
811 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
814 /* Restore child signals mask, previously returned by
815 block_child_signals. */
818 restore_child_signals_mask (sigset_t
*prev_mask
)
820 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
823 /* Mask of signals to pass directly to the inferior. */
824 static sigset_t pass_mask
;
826 /* Update signals to pass to the inferior. */
828 linux_nat_pass_signals (struct target_ops
*self
,
829 int numsigs
, unsigned char *pass_signals
)
833 sigemptyset (&pass_mask
);
835 for (signo
= 1; signo
< NSIG
; signo
++)
837 int target_signo
= gdb_signal_from_host (signo
);
838 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
839 sigaddset (&pass_mask
, signo
);
845 /* Prototypes for local functions. */
846 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
847 static int linux_thread_alive (ptid_t ptid
);
848 static char *linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
);
851 /* Convert wait status STATUS to a string. Used for printing debug
855 status_to_str (int status
)
859 if (WIFSTOPPED (status
))
861 if (WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
862 snprintf (buf
, sizeof (buf
), "%s (stopped at syscall)",
863 strsignal (SIGTRAP
));
865 snprintf (buf
, sizeof (buf
), "%s (stopped)",
866 strsignal (WSTOPSIG (status
)));
868 else if (WIFSIGNALED (status
))
869 snprintf (buf
, sizeof (buf
), "%s (terminated)",
870 strsignal (WTERMSIG (status
)));
872 snprintf (buf
, sizeof (buf
), "%d (exited)", WEXITSTATUS (status
));
877 /* Destroy and free LP. */
880 lwp_free (struct lwp_info
*lp
)
882 xfree (lp
->arch_private
);
886 /* Remove all LWPs belong to PID from the lwp list. */
889 purge_lwp_list (int pid
)
891 struct lwp_info
*lp
, *lpprev
, *lpnext
;
895 for (lp
= lwp_list
; lp
; lp
= lpnext
)
899 if (ptid_get_pid (lp
->ptid
) == pid
)
904 lpprev
->next
= lp
->next
;
913 /* Add the LWP specified by PTID to the list. PTID is the first LWP
914 in the process. Return a pointer to the structure describing the
917 This differs from add_lwp in that we don't let the arch specific
918 bits know about this new thread. Current clients of this callback
919 take the opportunity to install watchpoints in the new thread, and
920 we shouldn't do that for the first thread. If we're spawning a
921 child ("run"), the thread executes the shell wrapper first, and we
922 shouldn't touch it until it execs the program we want to debug.
923 For "attach", it'd be okay to call the callback, but it's not
924 necessary, because watchpoints can't yet have been inserted into
927 static struct lwp_info
*
928 add_initial_lwp (ptid_t ptid
)
932 gdb_assert (ptid_lwp_p (ptid
));
934 lp
= (struct lwp_info
*) xmalloc (sizeof (struct lwp_info
));
936 memset (lp
, 0, sizeof (struct lwp_info
));
938 lp
->last_resume_kind
= resume_continue
;
939 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
950 /* Add the LWP specified by PID to the list. Return a pointer to the
951 structure describing the new LWP. The LWP should already be
954 static struct lwp_info
*
955 add_lwp (ptid_t ptid
)
959 lp
= add_initial_lwp (ptid
);
961 /* Let the arch specific bits know about this new thread. Current
962 clients of this callback take the opportunity to install
963 watchpoints in the new thread. We don't do this for the first
964 thread though. See add_initial_lwp. */
965 if (linux_nat_new_thread
!= NULL
)
966 linux_nat_new_thread (lp
);
971 /* Remove the LWP specified by PID from the list. */
974 delete_lwp (ptid_t ptid
)
976 struct lwp_info
*lp
, *lpprev
;
980 for (lp
= lwp_list
; lp
; lpprev
= lp
, lp
= lp
->next
)
981 if (ptid_equal (lp
->ptid
, ptid
))
988 lpprev
->next
= lp
->next
;
995 /* Return a pointer to the structure describing the LWP corresponding
996 to PID. If no corresponding LWP could be found, return NULL. */
998 static struct lwp_info
*
999 find_lwp_pid (ptid_t ptid
)
1001 struct lwp_info
*lp
;
1004 if (ptid_lwp_p (ptid
))
1005 lwp
= ptid_get_lwp (ptid
);
1007 lwp
= ptid_get_pid (ptid
);
1009 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
1010 if (lwp
== ptid_get_lwp (lp
->ptid
))
1016 /* Call CALLBACK with its second argument set to DATA for every LWP in
1017 the list. If CALLBACK returns 1 for a particular LWP, return a
1018 pointer to the structure describing that LWP immediately.
1019 Otherwise return NULL. */
1022 iterate_over_lwps (ptid_t filter
,
1023 int (*callback
) (struct lwp_info
*, void *),
1026 struct lwp_info
*lp
, *lpnext
;
1028 for (lp
= lwp_list
; lp
; lp
= lpnext
)
1032 if (ptid_match (lp
->ptid
, filter
))
1034 if ((*callback
) (lp
, data
))
1042 /* Update our internal state when changing from one checkpoint to
1043 another indicated by NEW_PTID. We can only switch single-threaded
1044 applications, so we only create one new LWP, and the previous list
1048 linux_nat_switch_fork (ptid_t new_ptid
)
1050 struct lwp_info
*lp
;
1052 purge_lwp_list (ptid_get_pid (inferior_ptid
));
1054 lp
= add_lwp (new_ptid
);
1057 /* This changes the thread's ptid while preserving the gdb thread
1058 num. Also changes the inferior pid, while preserving the
1060 thread_change_ptid (inferior_ptid
, new_ptid
);
1062 /* We've just told GDB core that the thread changed target id, but,
1063 in fact, it really is a different thread, with different register
1065 registers_changed ();
1068 /* Handle the exit of a single thread LP. */
1071 exit_lwp (struct lwp_info
*lp
)
1073 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1077 if (print_thread_events
)
1078 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
1080 delete_thread (lp
->ptid
);
1083 delete_lwp (lp
->ptid
);
1086 /* Wait for the LWP specified by LP, which we have just attached to.
1087 Returns a wait status for that LWP, to cache. */
1090 linux_nat_post_attach_wait (ptid_t ptid
, int first
, int *cloned
,
1093 pid_t new_pid
, pid
= ptid_get_lwp (ptid
);
1096 if (linux_proc_pid_is_stopped (pid
))
1098 if (debug_linux_nat
)
1099 fprintf_unfiltered (gdb_stdlog
,
1100 "LNPAW: Attaching to a stopped process\n");
1102 /* The process is definitely stopped. It is in a job control
1103 stop, unless the kernel predates the TASK_STOPPED /
1104 TASK_TRACED distinction, in which case it might be in a
1105 ptrace stop. Make sure it is in a ptrace stop; from there we
1106 can kill it, signal it, et cetera.
1108 First make sure there is a pending SIGSTOP. Since we are
1109 already attached, the process can not transition from stopped
1110 to running without a PTRACE_CONT; so we know this signal will
1111 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1112 probably already in the queue (unless this kernel is old
1113 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1114 is not an RT signal, it can only be queued once. */
1115 kill_lwp (pid
, SIGSTOP
);
1117 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1118 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1119 ptrace (PTRACE_CONT
, pid
, 0, 0);
1122 /* Make sure the initial process is stopped. The user-level threads
1123 layer might want to poke around in the inferior, and that won't
1124 work if things haven't stabilized yet. */
1125 new_pid
= my_waitpid (pid
, &status
, 0);
1126 if (new_pid
== -1 && errno
== ECHILD
)
1129 warning (_("%s is a cloned process"), target_pid_to_str (ptid
));
1131 /* Try again with __WCLONE to check cloned processes. */
1132 new_pid
= my_waitpid (pid
, &status
, __WCLONE
);
1136 gdb_assert (pid
== new_pid
);
1138 if (!WIFSTOPPED (status
))
1140 /* The pid we tried to attach has apparently just exited. */
1141 if (debug_linux_nat
)
1142 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1143 pid
, status_to_str (status
));
1147 if (WSTOPSIG (status
) != SIGSTOP
)
1150 if (debug_linux_nat
)
1151 fprintf_unfiltered (gdb_stdlog
,
1152 "LNPAW: Received %s after attaching\n",
1153 status_to_str (status
));
1159 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1160 the new LWP could not be attached, or 1 if we're already auto
1161 attached to this thread, but haven't processed the
1162 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1163 its existance, without considering it an error. */
1166 lin_lwp_attach_lwp (ptid_t ptid
)
1168 struct lwp_info
*lp
;
1171 gdb_assert (ptid_lwp_p (ptid
));
1173 lp
= find_lwp_pid (ptid
);
1174 lwpid
= ptid_get_lwp (ptid
);
1176 /* We assume that we're already attached to any LWP that has an id
1177 equal to the overall process id, and to any LWP that is already
1178 in our list of LWPs. If we're not seeing exit events from threads
1179 and we've had PID wraparound since we last tried to stop all threads,
1180 this assumption might be wrong; fortunately, this is very unlikely
1182 if (lwpid
!= ptid_get_pid (ptid
) && lp
== NULL
)
1184 int status
, cloned
= 0, signalled
= 0;
1186 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1188 if (linux_supports_tracefork ())
1190 /* If we haven't stopped all threads when we get here,
1191 we may have seen a thread listed in thread_db's list,
1192 but not processed the PTRACE_EVENT_CLONE yet. If
1193 that's the case, ignore this new thread, and let
1194 normal event handling discover it later. */
1195 if (in_pid_list_p (stopped_pids
, lwpid
))
1197 /* We've already seen this thread stop, but we
1198 haven't seen the PTRACE_EVENT_CLONE extended
1207 /* See if we've got a stop for this new child
1208 pending. If so, we're already attached. */
1209 new_pid
= my_waitpid (lwpid
, &status
, WNOHANG
);
1210 if (new_pid
== -1 && errno
== ECHILD
)
1211 new_pid
= my_waitpid (lwpid
, &status
, __WCLONE
| WNOHANG
);
1214 if (WIFSTOPPED (status
))
1215 add_to_pid_list (&stopped_pids
, lwpid
, status
);
1221 /* If we fail to attach to the thread, issue a warning,
1222 but continue. One way this can happen is if thread
1223 creation is interrupted; as of Linux kernel 2.6.19, a
1224 bug may place threads in the thread list and then fail
1226 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid
),
1227 safe_strerror (errno
));
1231 if (debug_linux_nat
)
1232 fprintf_unfiltered (gdb_stdlog
,
1233 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1234 target_pid_to_str (ptid
));
1236 status
= linux_nat_post_attach_wait (ptid
, 0, &cloned
, &signalled
);
1237 if (!WIFSTOPPED (status
))
1240 lp
= add_lwp (ptid
);
1242 lp
->cloned
= cloned
;
1243 lp
->signalled
= signalled
;
1244 if (WSTOPSIG (status
) != SIGSTOP
)
1247 lp
->status
= status
;
1250 target_post_attach (ptid_get_lwp (lp
->ptid
));
1252 if (debug_linux_nat
)
1254 fprintf_unfiltered (gdb_stdlog
,
1255 "LLAL: waitpid %s received %s\n",
1256 target_pid_to_str (ptid
),
1257 status_to_str (status
));
1262 /* We assume that the LWP representing the original process is
1263 already stopped. Mark it as stopped in the data structure
1264 that the GNU/linux ptrace layer uses to keep track of
1265 threads. Note that this won't have already been done since
1266 the main thread will have, we assume, been stopped by an
1267 attach from a different layer. */
1269 lp
= add_lwp (ptid
);
1273 lp
->last_resume_kind
= resume_stop
;
1278 linux_nat_create_inferior (struct target_ops
*ops
,
1279 char *exec_file
, char *allargs
, char **env
,
1282 #ifdef HAVE_PERSONALITY
1283 int personality_orig
= 0, personality_set
= 0;
1284 #endif /* HAVE_PERSONALITY */
1286 /* The fork_child mechanism is synchronous and calls target_wait, so
1287 we have to mask the async mode. */
1289 #ifdef HAVE_PERSONALITY
1290 if (disable_randomization
)
1293 personality_orig
= personality (0xffffffff);
1294 if (errno
== 0 && !(personality_orig
& ADDR_NO_RANDOMIZE
))
1296 personality_set
= 1;
1297 personality (personality_orig
| ADDR_NO_RANDOMIZE
);
1299 if (errno
!= 0 || (personality_set
1300 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE
)))
1301 warning (_("Error disabling address space randomization: %s"),
1302 safe_strerror (errno
));
1304 #endif /* HAVE_PERSONALITY */
1306 /* Make sure we report all signals during startup. */
1307 linux_nat_pass_signals (ops
, 0, NULL
);
1309 linux_ops
->to_create_inferior (ops
, exec_file
, allargs
, env
, from_tty
);
1311 #ifdef HAVE_PERSONALITY
1312 if (personality_set
)
1315 personality (personality_orig
);
1317 warning (_("Error restoring address space randomization: %s"),
1318 safe_strerror (errno
));
1320 #endif /* HAVE_PERSONALITY */
1324 linux_nat_attach (struct target_ops
*ops
, char *args
, int from_tty
)
1326 struct lwp_info
*lp
;
1329 volatile struct gdb_exception ex
;
1331 /* Make sure we report all signals during attach. */
1332 linux_nat_pass_signals (ops
, 0, NULL
);
1334 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
1336 linux_ops
->to_attach (ops
, args
, from_tty
);
1340 pid_t pid
= parse_pid_to_attach (args
);
1341 struct buffer buffer
;
1342 char *message
, *buffer_s
;
1344 message
= xstrdup (ex
.message
);
1345 make_cleanup (xfree
, message
);
1347 buffer_init (&buffer
);
1348 linux_ptrace_attach_warnings (pid
, &buffer
);
1350 buffer_grow_str0 (&buffer
, "");
1351 buffer_s
= buffer_finish (&buffer
);
1352 make_cleanup (xfree
, buffer_s
);
1354 throw_error (ex
.error
, "%s%s", buffer_s
, message
);
1357 /* The ptrace base target adds the main thread with (pid,0,0)
1358 format. Decorate it with lwp info. */
1359 ptid
= ptid_build (ptid_get_pid (inferior_ptid
),
1360 ptid_get_pid (inferior_ptid
),
1362 thread_change_ptid (inferior_ptid
, ptid
);
1364 /* Add the initial process as the first LWP to the list. */
1365 lp
= add_initial_lwp (ptid
);
1367 status
= linux_nat_post_attach_wait (lp
->ptid
, 1, &lp
->cloned
,
1369 if (!WIFSTOPPED (status
))
1371 if (WIFEXITED (status
))
1373 int exit_code
= WEXITSTATUS (status
);
1375 target_terminal_ours ();
1376 target_mourn_inferior ();
1378 error (_("Unable to attach: program exited normally."));
1380 error (_("Unable to attach: program exited with code %d."),
1383 else if (WIFSIGNALED (status
))
1385 enum gdb_signal signo
;
1387 target_terminal_ours ();
1388 target_mourn_inferior ();
1390 signo
= gdb_signal_from_host (WTERMSIG (status
));
1391 error (_("Unable to attach: program terminated with signal "
1393 gdb_signal_to_name (signo
),
1394 gdb_signal_to_string (signo
));
1397 internal_error (__FILE__
, __LINE__
,
1398 _("unexpected status %d for PID %ld"),
1399 status
, (long) ptid_get_lwp (ptid
));
1404 /* Save the wait status to report later. */
1406 if (debug_linux_nat
)
1407 fprintf_unfiltered (gdb_stdlog
,
1408 "LNA: waitpid %ld, saving status %s\n",
1409 (long) ptid_get_pid (lp
->ptid
), status_to_str (status
));
1411 lp
->status
= status
;
1413 if (target_can_async_p ())
1414 target_async (inferior_event_handler
, 0);
1417 /* Get pending status of LP. */
1419 get_pending_status (struct lwp_info
*lp
, int *status
)
1421 enum gdb_signal signo
= GDB_SIGNAL_0
;
1423 /* If we paused threads momentarily, we may have stored pending
1424 events in lp->status or lp->waitstatus (see stop_wait_callback),
1425 and GDB core hasn't seen any signal for those threads.
1426 Otherwise, the last signal reported to the core is found in the
1427 thread object's stop_signal.
1429 There's a corner case that isn't handled here at present. Only
1430 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1431 stop_signal make sense as a real signal to pass to the inferior.
1432 Some catchpoint related events, like
1433 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1434 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1435 those traps are debug API (ptrace in our case) related and
1436 induced; the inferior wouldn't see them if it wasn't being
1437 traced. Hence, we should never pass them to the inferior, even
1438 when set to pass state. Since this corner case isn't handled by
1439 infrun.c when proceeding with a signal, for consistency, neither
1440 do we handle it here (or elsewhere in the file we check for
1441 signal pass state). Normally SIGTRAP isn't set to pass state, so
1442 this is really a corner case. */
1444 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1445 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1446 else if (lp
->status
)
1447 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1448 else if (non_stop
&& !is_executing (lp
->ptid
))
1450 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1452 signo
= tp
->suspend
.stop_signal
;
1456 struct target_waitstatus last
;
1459 get_last_target_status (&last_ptid
, &last
);
1461 if (ptid_get_lwp (lp
->ptid
) == ptid_get_lwp (last_ptid
))
1463 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1465 signo
= tp
->suspend
.stop_signal
;
1471 if (signo
== GDB_SIGNAL_0
)
1473 if (debug_linux_nat
)
1474 fprintf_unfiltered (gdb_stdlog
,
1475 "GPT: lwp %s has no pending signal\n",
1476 target_pid_to_str (lp
->ptid
));
1478 else if (!signal_pass_state (signo
))
1480 if (debug_linux_nat
)
1481 fprintf_unfiltered (gdb_stdlog
,
1482 "GPT: lwp %s had signal %s, "
1483 "but it is in no pass state\n",
1484 target_pid_to_str (lp
->ptid
),
1485 gdb_signal_to_string (signo
));
1489 *status
= W_STOPCODE (gdb_signal_to_host (signo
));
1491 if (debug_linux_nat
)
1492 fprintf_unfiltered (gdb_stdlog
,
1493 "GPT: lwp %s has pending signal %s\n",
1494 target_pid_to_str (lp
->ptid
),
1495 gdb_signal_to_string (signo
));
1502 detach_callback (struct lwp_info
*lp
, void *data
)
1504 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1506 if (debug_linux_nat
&& lp
->status
)
1507 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1508 strsignal (WSTOPSIG (lp
->status
)),
1509 target_pid_to_str (lp
->ptid
));
1511 /* If there is a pending SIGSTOP, get rid of it. */
1514 if (debug_linux_nat
)
1515 fprintf_unfiltered (gdb_stdlog
,
1516 "DC: Sending SIGCONT to %s\n",
1517 target_pid_to_str (lp
->ptid
));
1519 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGCONT
);
1523 /* We don't actually detach from the LWP that has an id equal to the
1524 overall process id just yet. */
1525 if (ptid_get_lwp (lp
->ptid
) != ptid_get_pid (lp
->ptid
))
1529 /* Pass on any pending signal for this LWP. */
1530 get_pending_status (lp
, &status
);
1532 if (linux_nat_prepare_to_resume
!= NULL
)
1533 linux_nat_prepare_to_resume (lp
);
1535 if (ptrace (PTRACE_DETACH
, ptid_get_lwp (lp
->ptid
), 0,
1536 WSTOPSIG (status
)) < 0)
1537 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1538 safe_strerror (errno
));
1540 if (debug_linux_nat
)
1541 fprintf_unfiltered (gdb_stdlog
,
1542 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1543 target_pid_to_str (lp
->ptid
),
1544 strsignal (WSTOPSIG (status
)));
1546 delete_lwp (lp
->ptid
);
1553 linux_nat_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1557 struct lwp_info
*main_lwp
;
1559 pid
= ptid_get_pid (inferior_ptid
);
1561 /* Don't unregister from the event loop, as there may be other
1562 inferiors running. */
1564 /* Stop all threads before detaching. ptrace requires that the
1565 thread is stopped to sucessfully detach. */
1566 iterate_over_lwps (pid_to_ptid (pid
), stop_callback
, NULL
);
1567 /* ... and wait until all of them have reported back that
1568 they're no longer running. */
1569 iterate_over_lwps (pid_to_ptid (pid
), stop_wait_callback
, NULL
);
1571 iterate_over_lwps (pid_to_ptid (pid
), detach_callback
, NULL
);
1573 /* Only the initial process should be left right now. */
1574 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid
)) == 1);
1576 main_lwp
= find_lwp_pid (pid_to_ptid (pid
));
1578 /* Pass on any pending signal for the last LWP. */
1579 if ((args
== NULL
|| *args
== '\0')
1580 && get_pending_status (main_lwp
, &status
) != -1
1581 && WIFSTOPPED (status
))
1585 /* Put the signal number in ARGS so that inf_ptrace_detach will
1586 pass it along with PTRACE_DETACH. */
1588 xsnprintf (tem
, 8, "%d", (int) WSTOPSIG (status
));
1590 if (debug_linux_nat
)
1591 fprintf_unfiltered (gdb_stdlog
,
1592 "LND: Sending signal %s to %s\n",
1594 target_pid_to_str (main_lwp
->ptid
));
1597 if (linux_nat_prepare_to_resume
!= NULL
)
1598 linux_nat_prepare_to_resume (main_lwp
);
1599 delete_lwp (main_lwp
->ptid
);
1601 if (forks_exist_p ())
1603 /* Multi-fork case. The current inferior_ptid is being detached
1604 from, but there are other viable forks to debug. Detach from
1605 the current fork, and context-switch to the first
1607 linux_fork_detach (args
, from_tty
);
1610 linux_ops
->to_detach (ops
, args
, from_tty
);
1616 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1620 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
1622 if (inf
->vfork_child
!= NULL
)
1624 if (debug_linux_nat
)
1625 fprintf_unfiltered (gdb_stdlog
,
1626 "RC: Not resuming %s (vfork parent)\n",
1627 target_pid_to_str (lp
->ptid
));
1629 else if (lp
->status
== 0
1630 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
1632 if (debug_linux_nat
)
1633 fprintf_unfiltered (gdb_stdlog
,
1634 "RC: Resuming sibling %s, %s, %s\n",
1635 target_pid_to_str (lp
->ptid
),
1636 (signo
!= GDB_SIGNAL_0
1637 ? strsignal (gdb_signal_to_host (signo
))
1639 step
? "step" : "resume");
1641 if (linux_nat_prepare_to_resume
!= NULL
)
1642 linux_nat_prepare_to_resume (lp
);
1643 linux_ops
->to_resume (linux_ops
,
1644 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
1648 lp
->stopped_by_watchpoint
= 0;
1652 if (debug_linux_nat
)
1653 fprintf_unfiltered (gdb_stdlog
,
1654 "RC: Not resuming sibling %s (has pending)\n",
1655 target_pid_to_str (lp
->ptid
));
1660 if (debug_linux_nat
)
1661 fprintf_unfiltered (gdb_stdlog
,
1662 "RC: Not resuming sibling %s (not stopped)\n",
1663 target_pid_to_str (lp
->ptid
));
1667 /* Resume LWP, with the last stop signal, if it is in pass state. */
1670 linux_nat_resume_callback (struct lwp_info
*lp
, void *data
)
1672 enum gdb_signal signo
= GDB_SIGNAL_0
;
1676 struct thread_info
*thread
;
1678 thread
= find_thread_ptid (lp
->ptid
);
1681 if (signal_pass_state (thread
->suspend
.stop_signal
))
1682 signo
= thread
->suspend
.stop_signal
;
1683 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1687 resume_lwp (lp
, 0, signo
);
1692 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1695 lp
->last_resume_kind
= resume_stop
;
1700 resume_set_callback (struct lwp_info
*lp
, void *data
)
1703 lp
->last_resume_kind
= resume_continue
;
1708 linux_nat_resume (struct target_ops
*ops
,
1709 ptid_t ptid
, int step
, enum gdb_signal signo
)
1711 struct lwp_info
*lp
;
1714 if (debug_linux_nat
)
1715 fprintf_unfiltered (gdb_stdlog
,
1716 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1717 step
? "step" : "resume",
1718 target_pid_to_str (ptid
),
1719 (signo
!= GDB_SIGNAL_0
1720 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1721 target_pid_to_str (inferior_ptid
));
1723 /* A specific PTID means `step only this process id'. */
1724 resume_many
= (ptid_equal (minus_one_ptid
, ptid
)
1725 || ptid_is_pid (ptid
));
1727 /* Mark the lwps we're resuming as resumed. */
1728 iterate_over_lwps (ptid
, resume_set_callback
, NULL
);
1730 /* See if it's the current inferior that should be handled
1733 lp
= find_lwp_pid (inferior_ptid
);
1735 lp
= find_lwp_pid (ptid
);
1736 gdb_assert (lp
!= NULL
);
1738 /* Remember if we're stepping. */
1740 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1742 /* If we have a pending wait status for this thread, there is no
1743 point in resuming the process. But first make sure that
1744 linux_nat_wait won't preemptively handle the event - we
1745 should never take this short-circuit if we are going to
1746 leave LP running, since we have skipped resuming all the
1747 other threads. This bit of code needs to be synchronized
1748 with linux_nat_wait. */
1750 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1753 && WSTOPSIG (lp
->status
)
1754 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1756 if (debug_linux_nat
)
1757 fprintf_unfiltered (gdb_stdlog
,
1758 "LLR: Not short circuiting for ignored "
1759 "status 0x%x\n", lp
->status
);
1761 /* FIXME: What should we do if we are supposed to continue
1762 this thread with a signal? */
1763 gdb_assert (signo
== GDB_SIGNAL_0
);
1764 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1769 if (lp
->status
|| lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1771 /* FIXME: What should we do if we are supposed to continue
1772 this thread with a signal? */
1773 gdb_assert (signo
== GDB_SIGNAL_0
);
1775 if (debug_linux_nat
)
1776 fprintf_unfiltered (gdb_stdlog
,
1777 "LLR: Short circuiting for status 0x%x\n",
1780 if (target_can_async_p ())
1782 target_async (inferior_event_handler
, 0);
1783 /* Tell the event loop we have something to process. */
1789 /* Mark LWP as not stopped to prevent it from being continued by
1790 linux_nat_resume_callback. */
1794 iterate_over_lwps (ptid
, linux_nat_resume_callback
, NULL
);
1796 /* Convert to something the lower layer understands. */
1797 ptid
= pid_to_ptid (ptid_get_lwp (lp
->ptid
));
1799 if (linux_nat_prepare_to_resume
!= NULL
)
1800 linux_nat_prepare_to_resume (lp
);
1801 linux_ops
->to_resume (linux_ops
, ptid
, step
, signo
);
1802 lp
->stopped_by_watchpoint
= 0;
1804 if (debug_linux_nat
)
1805 fprintf_unfiltered (gdb_stdlog
,
1806 "LLR: %s %s, %s (resume event thread)\n",
1807 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1808 target_pid_to_str (ptid
),
1809 (signo
!= GDB_SIGNAL_0
1810 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1812 if (target_can_async_p ())
1813 target_async (inferior_event_handler
, 0);
1816 /* Send a signal to an LWP. */
1819 kill_lwp (int lwpid
, int signo
)
1821 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1822 fails, then we are not using nptl threads and we should be using kill. */
1824 #ifdef HAVE_TKILL_SYSCALL
1826 static int tkill_failed
;
1833 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1834 if (errno
!= ENOSYS
)
1841 return kill (lwpid
, signo
);
1844 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1845 event, check if the core is interested in it: if not, ignore the
1846 event, and keep waiting; otherwise, we need to toggle the LWP's
1847 syscall entry/exit status, since the ptrace event itself doesn't
1848 indicate it, and report the trap to higher layers. */
1851 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1853 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1854 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1855 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, lp
->ptid
);
1859 /* If we're stopping threads, there's a SIGSTOP pending, which
1860 makes it so that the LWP reports an immediate syscall return,
1861 followed by the SIGSTOP. Skip seeing that "return" using
1862 PTRACE_CONT directly, and let stop_wait_callback collect the
1863 SIGSTOP. Later when the thread is resumed, a new syscall
1864 entry event. If we didn't do this (and returned 0), we'd
1865 leave a syscall entry pending, and our caller, by using
1866 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1867 itself. Later, when the user re-resumes this LWP, we'd see
1868 another syscall entry event and we'd mistake it for a return.
1870 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1871 (leaving immediately with LWP->signalled set, without issuing
1872 a PTRACE_CONT), it would still be problematic to leave this
1873 syscall enter pending, as later when the thread is resumed,
1874 it would then see the same syscall exit mentioned above,
1875 followed by the delayed SIGSTOP, while the syscall didn't
1876 actually get to execute. It seems it would be even more
1877 confusing to the user. */
1879 if (debug_linux_nat
)
1880 fprintf_unfiltered (gdb_stdlog
,
1881 "LHST: ignoring syscall %d "
1882 "for LWP %ld (stopping threads), "
1883 "resuming with PTRACE_CONT for SIGSTOP\n",
1885 ptid_get_lwp (lp
->ptid
));
1887 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1888 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
1892 if (catch_syscall_enabled ())
1894 /* Always update the entry/return state, even if this particular
1895 syscall isn't interesting to the core now. In async mode,
1896 the user could install a new catchpoint for this syscall
1897 between syscall enter/return, and we'll need to know to
1898 report a syscall return if that happens. */
1899 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1900 ? TARGET_WAITKIND_SYSCALL_RETURN
1901 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1903 if (catching_syscall_number (syscall_number
))
1905 /* Alright, an event to report. */
1906 ourstatus
->kind
= lp
->syscall_state
;
1907 ourstatus
->value
.syscall_number
= syscall_number
;
1909 if (debug_linux_nat
)
1910 fprintf_unfiltered (gdb_stdlog
,
1911 "LHST: stopping for %s of syscall %d"
1914 == TARGET_WAITKIND_SYSCALL_ENTRY
1915 ? "entry" : "return",
1917 ptid_get_lwp (lp
->ptid
));
1921 if (debug_linux_nat
)
1922 fprintf_unfiltered (gdb_stdlog
,
1923 "LHST: ignoring %s of syscall %d "
1925 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1926 ? "entry" : "return",
1928 ptid_get_lwp (lp
->ptid
));
1932 /* If we had been syscall tracing, and hence used PT_SYSCALL
1933 before on this LWP, it could happen that the user removes all
1934 syscall catchpoints before we get to process this event.
1935 There are two noteworthy issues here:
1937 - When stopped at a syscall entry event, resuming with
1938 PT_STEP still resumes executing the syscall and reports a
1941 - Only PT_SYSCALL catches syscall enters. If we last
1942 single-stepped this thread, then this event can't be a
1943 syscall enter. If we last single-stepped this thread, this
1944 has to be a syscall exit.
1946 The points above mean that the next resume, be it PT_STEP or
1947 PT_CONTINUE, can not trigger a syscall trace event. */
1948 if (debug_linux_nat
)
1949 fprintf_unfiltered (gdb_stdlog
,
1950 "LHST: caught syscall event "
1951 "with no syscall catchpoints."
1952 " %d for LWP %ld, ignoring\n",
1954 ptid_get_lwp (lp
->ptid
));
1955 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1958 /* The core isn't interested in this event. For efficiency, avoid
1959 stopping all threads only to have the core resume them all again.
1960 Since we're not stopping threads, if we're still syscall tracing
1961 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1962 subsequent syscall. Simply resume using the inf-ptrace layer,
1963 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1965 /* Note that gdbarch_get_syscall_number may access registers, hence
1967 registers_changed ();
1968 if (linux_nat_prepare_to_resume
!= NULL
)
1969 linux_nat_prepare_to_resume (lp
);
1970 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
1971 lp
->step
, GDB_SIGNAL_0
);
1975 /* Handle a GNU/Linux extended wait response. If we see a clone
1976 event, we need to add the new LWP to our list (and not report the
1977 trap to higher layers). This function returns non-zero if the
1978 event should be ignored and we should wait again. If STOPPING is
1979 true, the new LWP remains stopped, otherwise it is continued. */
1982 linux_handle_extended_wait (struct lwp_info
*lp
, int status
,
1985 int pid
= ptid_get_lwp (lp
->ptid
);
1986 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1987 int event
= status
>> 16;
1989 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1990 || event
== PTRACE_EVENT_CLONE
)
1992 unsigned long new_pid
;
1995 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1997 /* If we haven't already seen the new PID stop, wait for it now. */
1998 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
2000 /* The new child has a pending SIGSTOP. We can't affect it until it
2001 hits the SIGSTOP, but we're already attached. */
2002 ret
= my_waitpid (new_pid
, &status
,
2003 (event
== PTRACE_EVENT_CLONE
) ? __WCLONE
: 0);
2005 perror_with_name (_("waiting for new child"));
2006 else if (ret
!= new_pid
)
2007 internal_error (__FILE__
, __LINE__
,
2008 _("wait returned unexpected PID %d"), ret
);
2009 else if (!WIFSTOPPED (status
))
2010 internal_error (__FILE__
, __LINE__
,
2011 _("wait returned unexpected status 0x%x"), status
);
2014 ourstatus
->value
.related_pid
= ptid_build (new_pid
, new_pid
, 0);
2016 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
2018 /* The arch-specific native code may need to know about new
2019 forks even if those end up never mapped to an
2021 if (linux_nat_new_fork
!= NULL
)
2022 linux_nat_new_fork (lp
, new_pid
);
2025 if (event
== PTRACE_EVENT_FORK
2026 && linux_fork_checkpointing_p (ptid_get_pid (lp
->ptid
)))
2028 /* Handle checkpointing by linux-fork.c here as a special
2029 case. We don't want the follow-fork-mode or 'catch fork'
2030 to interfere with this. */
2032 /* This won't actually modify the breakpoint list, but will
2033 physically remove the breakpoints from the child. */
2034 detach_breakpoints (ptid_build (new_pid
, new_pid
, 0));
2036 /* Retain child fork in ptrace (stopped) state. */
2037 if (!find_fork_pid (new_pid
))
2040 /* Report as spurious, so that infrun doesn't want to follow
2041 this fork. We're actually doing an infcall in
2043 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
2045 /* Report the stop to the core. */
2049 if (event
== PTRACE_EVENT_FORK
)
2050 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
2051 else if (event
== PTRACE_EVENT_VFORK
)
2052 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
2055 struct lwp_info
*new_lp
;
2057 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2059 if (debug_linux_nat
)
2060 fprintf_unfiltered (gdb_stdlog
,
2061 "LHEW: Got clone event "
2062 "from LWP %d, new child is LWP %ld\n",
2065 new_lp
= add_lwp (ptid_build (ptid_get_pid (lp
->ptid
), new_pid
, 0));
2067 new_lp
->stopped
= 1;
2069 if (WSTOPSIG (status
) != SIGSTOP
)
2071 /* This can happen if someone starts sending signals to
2072 the new thread before it gets a chance to run, which
2073 have a lower number than SIGSTOP (e.g. SIGUSR1).
2074 This is an unlikely case, and harder to handle for
2075 fork / vfork than for clone, so we do not try - but
2076 we handle it for clone events here. We'll send
2077 the other signal on to the thread below. */
2079 new_lp
->signalled
= 1;
2083 struct thread_info
*tp
;
2085 /* When we stop for an event in some other thread, and
2086 pull the thread list just as this thread has cloned,
2087 we'll have seen the new thread in the thread_db list
2088 before handling the CLONE event (glibc's
2089 pthread_create adds the new thread to the thread list
2090 before clone'ing, and has the kernel fill in the
2091 thread's tid on the clone call with
2092 CLONE_PARENT_SETTID). If that happened, and the core
2093 had requested the new thread to stop, we'll have
2094 killed it with SIGSTOP. But since SIGSTOP is not an
2095 RT signal, it can only be queued once. We need to be
2096 careful to not resume the LWP if we wanted it to
2097 stop. In that case, we'll leave the SIGSTOP pending.
2098 It will later be reported as GDB_SIGNAL_0. */
2099 tp
= find_thread_ptid (new_lp
->ptid
);
2100 if (tp
!= NULL
&& tp
->stop_requested
)
2101 new_lp
->last_resume_kind
= resume_stop
;
2108 /* Add the new thread to GDB's lists as soon as possible
2111 1) the frontend doesn't have to wait for a stop to
2114 2) we tag it with the correct running state. */
2116 /* If the thread_db layer is active, let it know about
2117 this new thread, and add it to GDB's list. */
2118 if (!thread_db_attach_lwp (new_lp
->ptid
))
2120 /* We're not using thread_db. Add it to GDB's
2122 target_post_attach (ptid_get_lwp (new_lp
->ptid
));
2123 add_thread (new_lp
->ptid
);
2128 set_running (new_lp
->ptid
, 1);
2129 set_executing (new_lp
->ptid
, 1);
2130 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2132 new_lp
->last_resume_kind
= resume_continue
;
2138 /* We created NEW_LP so it cannot yet contain STATUS. */
2139 gdb_assert (new_lp
->status
== 0);
2141 /* Save the wait status to report later. */
2142 if (debug_linux_nat
)
2143 fprintf_unfiltered (gdb_stdlog
,
2144 "LHEW: waitpid of new LWP %ld, "
2145 "saving status %s\n",
2146 (long) ptid_get_lwp (new_lp
->ptid
),
2147 status_to_str (status
));
2148 new_lp
->status
= status
;
2151 /* Note the need to use the low target ops to resume, to
2152 handle resuming with PT_SYSCALL if we have syscall
2156 new_lp
->resumed
= 1;
2160 gdb_assert (new_lp
->last_resume_kind
== resume_continue
);
2161 if (debug_linux_nat
)
2162 fprintf_unfiltered (gdb_stdlog
,
2163 "LHEW: resuming new LWP %ld\n",
2164 ptid_get_lwp (new_lp
->ptid
));
2165 if (linux_nat_prepare_to_resume
!= NULL
)
2166 linux_nat_prepare_to_resume (new_lp
);
2167 linux_ops
->to_resume (linux_ops
, pid_to_ptid (new_pid
),
2169 new_lp
->stopped
= 0;
2173 if (debug_linux_nat
)
2174 fprintf_unfiltered (gdb_stdlog
,
2175 "LHEW: resuming parent LWP %d\n", pid
);
2176 if (linux_nat_prepare_to_resume
!= NULL
)
2177 linux_nat_prepare_to_resume (lp
);
2178 linux_ops
->to_resume (linux_ops
,
2179 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
2188 if (event
== PTRACE_EVENT_EXEC
)
2190 if (debug_linux_nat
)
2191 fprintf_unfiltered (gdb_stdlog
,
2192 "LHEW: Got exec event from LWP %ld\n",
2193 ptid_get_lwp (lp
->ptid
));
2195 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2196 ourstatus
->value
.execd_pathname
2197 = xstrdup (linux_child_pid_to_exec_file (NULL
, pid
));
2202 if (event
== PTRACE_EVENT_VFORK_DONE
)
2204 if (current_inferior ()->waiting_for_vfork_done
)
2206 if (debug_linux_nat
)
2207 fprintf_unfiltered (gdb_stdlog
,
2208 "LHEW: Got expected PTRACE_EVENT_"
2209 "VFORK_DONE from LWP %ld: stopping\n",
2210 ptid_get_lwp (lp
->ptid
));
2212 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2216 if (debug_linux_nat
)
2217 fprintf_unfiltered (gdb_stdlog
,
2218 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2219 "from LWP %ld: resuming\n",
2220 ptid_get_lwp (lp
->ptid
));
2221 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2225 internal_error (__FILE__
, __LINE__
,
2226 _("unknown ptrace event %d"), event
);
2229 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2233 wait_lwp (struct lwp_info
*lp
)
2237 int thread_dead
= 0;
2240 gdb_assert (!lp
->stopped
);
2241 gdb_assert (lp
->status
== 0);
2243 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2244 block_child_signals (&prev_mask
);
2248 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2249 was right and we should just call sigsuspend. */
2251 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, WNOHANG
);
2252 if (pid
== -1 && errno
== ECHILD
)
2253 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, __WCLONE
| WNOHANG
);
2254 if (pid
== -1 && errno
== ECHILD
)
2256 /* The thread has previously exited. We need to delete it
2257 now because, for some vendor 2.4 kernels with NPTL
2258 support backported, there won't be an exit event unless
2259 it is the main thread. 2.6 kernels will report an exit
2260 event for each thread that exits, as expected. */
2262 if (debug_linux_nat
)
2263 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2264 target_pid_to_str (lp
->ptid
));
2269 /* Bugs 10970, 12702.
2270 Thread group leader may have exited in which case we'll lock up in
2271 waitpid if there are other threads, even if they are all zombies too.
2272 Basically, we're not supposed to use waitpid this way.
2273 __WCLONE is not applicable for the leader so we can't use that.
2274 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2275 process; it gets ESRCH both for the zombie and for running processes.
2277 As a workaround, check if we're waiting for the thread group leader and
2278 if it's a zombie, and avoid calling waitpid if it is.
2280 This is racy, what if the tgl becomes a zombie right after we check?
2281 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2282 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2284 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
)
2285 && linux_proc_pid_is_zombie (ptid_get_lwp (lp
->ptid
)))
2288 if (debug_linux_nat
)
2289 fprintf_unfiltered (gdb_stdlog
,
2290 "WL: Thread group leader %s vanished.\n",
2291 target_pid_to_str (lp
->ptid
));
2295 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2296 get invoked despite our caller had them intentionally blocked by
2297 block_child_signals. This is sensitive only to the loop of
2298 linux_nat_wait_1 and there if we get called my_waitpid gets called
2299 again before it gets to sigsuspend so we can safely let the handlers
2300 get executed here. */
2302 sigsuspend (&suspend_mask
);
2305 restore_child_signals_mask (&prev_mask
);
2309 gdb_assert (pid
== ptid_get_lwp (lp
->ptid
));
2311 if (debug_linux_nat
)
2313 fprintf_unfiltered (gdb_stdlog
,
2314 "WL: waitpid %s received %s\n",
2315 target_pid_to_str (lp
->ptid
),
2316 status_to_str (status
));
2319 /* Check if the thread has exited. */
2320 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2323 if (debug_linux_nat
)
2324 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2325 target_pid_to_str (lp
->ptid
));
2335 gdb_assert (WIFSTOPPED (status
));
2337 /* Handle GNU/Linux's syscall SIGTRAPs. */
2338 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2340 /* No longer need the sysgood bit. The ptrace event ends up
2341 recorded in lp->waitstatus if we care for it. We can carry
2342 on handling the event like a regular SIGTRAP from here
2344 status
= W_STOPCODE (SIGTRAP
);
2345 if (linux_handle_syscall_trap (lp
, 1))
2346 return wait_lwp (lp
);
2349 /* Handle GNU/Linux's extended waitstatus for trace events. */
2350 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2352 if (debug_linux_nat
)
2353 fprintf_unfiltered (gdb_stdlog
,
2354 "WL: Handling extended status 0x%06x\n",
2356 if (linux_handle_extended_wait (lp
, status
, 1))
2357 return wait_lwp (lp
);
2363 /* Send a SIGSTOP to LP. */
2366 stop_callback (struct lwp_info
*lp
, void *data
)
2368 if (!lp
->stopped
&& !lp
->signalled
)
2372 if (debug_linux_nat
)
2374 fprintf_unfiltered (gdb_stdlog
,
2375 "SC: kill %s **<SIGSTOP>**\n",
2376 target_pid_to_str (lp
->ptid
));
2379 ret
= kill_lwp (ptid_get_lwp (lp
->ptid
), SIGSTOP
);
2380 if (debug_linux_nat
)
2382 fprintf_unfiltered (gdb_stdlog
,
2383 "SC: lwp kill %d %s\n",
2385 errno
? safe_strerror (errno
) : "ERRNO-OK");
2389 gdb_assert (lp
->status
== 0);
2395 /* Request a stop on LWP. */
2398 linux_stop_lwp (struct lwp_info
*lwp
)
2400 stop_callback (lwp
, NULL
);
2403 /* Return non-zero if LWP PID has a pending SIGINT. */
2406 linux_nat_has_pending_sigint (int pid
)
2408 sigset_t pending
, blocked
, ignored
;
2410 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2412 if (sigismember (&pending
, SIGINT
)
2413 && !sigismember (&ignored
, SIGINT
))
2419 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2422 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2424 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2425 flag to consume the next one. */
2426 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2427 && WSTOPSIG (lp
->status
) == SIGINT
)
2430 lp
->ignore_sigint
= 1;
2435 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2436 This function is called after we know the LWP has stopped; if the LWP
2437 stopped before the expected SIGINT was delivered, then it will never have
2438 arrived. Also, if the signal was delivered to a shared queue and consumed
2439 by a different thread, it will never be delivered to this LWP. */
2442 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2444 if (!lp
->ignore_sigint
)
2447 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp
->ptid
)))
2449 if (debug_linux_nat
)
2450 fprintf_unfiltered (gdb_stdlog
,
2451 "MCIS: Clearing bogus flag for %s\n",
2452 target_pid_to_str (lp
->ptid
));
2453 lp
->ignore_sigint
= 0;
2457 /* Fetch the possible triggered data watchpoint info and store it in
2460 On some archs, like x86, that use debug registers to set
2461 watchpoints, it's possible that the way to know which watched
2462 address trapped, is to check the register that is used to select
2463 which address to watch. Problem is, between setting the watchpoint
2464 and reading back which data address trapped, the user may change
2465 the set of watchpoints, and, as a consequence, GDB changes the
2466 debug registers in the inferior. To avoid reading back a stale
2467 stopped-data-address when that happens, we cache in LP the fact
2468 that a watchpoint trapped, and the corresponding data address, as
2469 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2470 registers meanwhile, we have the cached data we can rely on. */
2473 save_sigtrap (struct lwp_info
*lp
)
2475 struct cleanup
*old_chain
;
2477 if (linux_ops
->to_stopped_by_watchpoint
== NULL
)
2479 lp
->stopped_by_watchpoint
= 0;
2483 old_chain
= save_inferior_ptid ();
2484 inferior_ptid
= lp
->ptid
;
2486 lp
->stopped_by_watchpoint
= linux_ops
->to_stopped_by_watchpoint (linux_ops
);
2488 if (lp
->stopped_by_watchpoint
)
2490 if (linux_ops
->to_stopped_data_address
!= NULL
)
2491 lp
->stopped_data_address_p
=
2492 linux_ops
->to_stopped_data_address (¤t_target
,
2493 &lp
->stopped_data_address
);
2495 lp
->stopped_data_address_p
= 0;
2498 do_cleanups (old_chain
);
2501 /* See save_sigtrap. */
2504 linux_nat_stopped_by_watchpoint (struct target_ops
*ops
)
2506 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2508 gdb_assert (lp
!= NULL
);
2510 return lp
->stopped_by_watchpoint
;
2514 linux_nat_stopped_data_address (struct target_ops
*ops
, CORE_ADDR
*addr_p
)
2516 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2518 gdb_assert (lp
!= NULL
);
2520 *addr_p
= lp
->stopped_data_address
;
2522 return lp
->stopped_data_address_p
;
2525 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2528 sigtrap_is_event (int status
)
2530 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2533 /* SIGTRAP-like events recognizer. */
2535 static int (*linux_nat_status_is_event
) (int status
) = sigtrap_is_event
;
2537 /* Check for SIGTRAP-like events in LP. */
2540 linux_nat_lp_status_is_event (struct lwp_info
*lp
)
2542 /* We check for lp->waitstatus in addition to lp->status, because we can
2543 have pending process exits recorded in lp->status
2544 and W_EXITCODE(0,0) == 0. We should probably have an additional
2545 lp->status_p flag. */
2547 return (lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
2548 && linux_nat_status_is_event (lp
->status
));
2551 /* Set alternative SIGTRAP-like events recognizer. If
2552 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2556 linux_nat_set_status_is_event (struct target_ops
*t
,
2557 int (*status_is_event
) (int status
))
2559 linux_nat_status_is_event
= status_is_event
;
2562 /* Wait until LP is stopped. */
2565 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2567 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2569 /* If this is a vfork parent, bail out, it is not going to report
2570 any SIGSTOP until the vfork is done with. */
2571 if (inf
->vfork_child
!= NULL
)
2578 status
= wait_lwp (lp
);
2582 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2583 && WSTOPSIG (status
) == SIGINT
)
2585 lp
->ignore_sigint
= 0;
2588 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2589 if (debug_linux_nat
)
2590 fprintf_unfiltered (gdb_stdlog
,
2591 "PTRACE_CONT %s, 0, 0 (%s) "
2592 "(discarding SIGINT)\n",
2593 target_pid_to_str (lp
->ptid
),
2594 errno
? safe_strerror (errno
) : "OK");
2596 return stop_wait_callback (lp
, NULL
);
2599 maybe_clear_ignore_sigint (lp
);
2601 if (WSTOPSIG (status
) != SIGSTOP
)
2603 /* The thread was stopped with a signal other than SIGSTOP. */
2607 if (debug_linux_nat
)
2608 fprintf_unfiltered (gdb_stdlog
,
2609 "SWC: Pending event %s in %s\n",
2610 status_to_str ((int) status
),
2611 target_pid_to_str (lp
->ptid
));
2613 /* Save the sigtrap event. */
2614 lp
->status
= status
;
2615 gdb_assert (!lp
->stopped
);
2616 gdb_assert (lp
->signalled
);
2621 /* We caught the SIGSTOP that we intended to catch, so
2622 there's no SIGSTOP pending. */
2624 if (debug_linux_nat
)
2625 fprintf_unfiltered (gdb_stdlog
,
2626 "SWC: Delayed SIGSTOP caught for %s.\n",
2627 target_pid_to_str (lp
->ptid
));
2631 /* Reset SIGNALLED only after the stop_wait_callback call
2632 above as it does gdb_assert on SIGNALLED. */
2640 /* Return non-zero if LP has a wait status pending. */
2643 status_callback (struct lwp_info
*lp
, void *data
)
2645 /* Only report a pending wait status if we pretend that this has
2646 indeed been resumed. */
2650 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2652 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2653 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2654 0', so a clean process exit can not be stored pending in
2655 lp->status, it is indistinguishable from
2656 no-pending-status. */
2660 if (lp
->status
!= 0)
2666 /* Return non-zero if LP isn't stopped. */
2669 running_callback (struct lwp_info
*lp
, void *data
)
2671 return (!lp
->stopped
2672 || ((lp
->status
!= 0
2673 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2677 /* Count the LWP's that have had events. */
2680 count_events_callback (struct lwp_info
*lp
, void *data
)
2684 gdb_assert (count
!= NULL
);
2686 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2687 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2693 /* Select the LWP (if any) that is currently being single-stepped. */
2696 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2698 if (lp
->last_resume_kind
== resume_step
2705 /* Select the Nth LWP that has had a SIGTRAP event. */
2708 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2710 int *selector
= data
;
2712 gdb_assert (selector
!= NULL
);
2714 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2715 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2716 if ((*selector
)-- == 0)
2723 cancel_breakpoint (struct lwp_info
*lp
)
2725 /* Arrange for a breakpoint to be hit again later. We don't keep
2726 the SIGTRAP status and don't forward the SIGTRAP signal to the
2727 LWP. We will handle the current event, eventually we will resume
2728 this LWP, and this breakpoint will trap again.
2730 If we do not do this, then we run the risk that the user will
2731 delete or disable the breakpoint, but the LWP will have already
2734 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2735 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2738 pc
= regcache_read_pc (regcache
) - target_decr_pc_after_break (gdbarch
);
2739 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2741 if (debug_linux_nat
)
2742 fprintf_unfiltered (gdb_stdlog
,
2743 "CB: Push back breakpoint for %s\n",
2744 target_pid_to_str (lp
->ptid
));
2746 /* Back up the PC if necessary. */
2747 if (target_decr_pc_after_break (gdbarch
))
2748 regcache_write_pc (regcache
, pc
);
2756 cancel_breakpoints_callback (struct lwp_info
*lp
, void *data
)
2758 struct lwp_info
*event_lp
= data
;
2760 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2764 /* If a LWP other than the LWP that we're reporting an event for has
2765 hit a GDB breakpoint (as opposed to some random trap signal),
2766 then just arrange for it to hit it again later. We don't keep
2767 the SIGTRAP status and don't forward the SIGTRAP signal to the
2768 LWP. We will handle the current event, eventually we will resume
2769 all LWPs, and this one will get its breakpoint trap again.
2771 If we do not do this, then we run the risk that the user will
2772 delete or disable the breakpoint, but the LWP will have already
2775 if (linux_nat_lp_status_is_event (lp
)
2776 && cancel_breakpoint (lp
))
2777 /* Throw away the SIGTRAP. */
2783 /* Select one LWP out of those that have events pending. */
2786 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2789 int random_selector
;
2790 struct lwp_info
*event_lp
;
2792 /* Record the wait status for the original LWP. */
2793 (*orig_lp
)->status
= *status
;
2795 /* Give preference to any LWP that is being single-stepped. */
2796 event_lp
= iterate_over_lwps (filter
,
2797 select_singlestep_lwp_callback
, NULL
);
2798 if (event_lp
!= NULL
)
2800 if (debug_linux_nat
)
2801 fprintf_unfiltered (gdb_stdlog
,
2802 "SEL: Select single-step %s\n",
2803 target_pid_to_str (event_lp
->ptid
));
2807 /* No single-stepping LWP. Select one at random, out of those
2808 which have had SIGTRAP events. */
2810 /* First see how many SIGTRAP events we have. */
2811 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2813 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2814 random_selector
= (int)
2815 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2817 if (debug_linux_nat
&& num_events
> 1)
2818 fprintf_unfiltered (gdb_stdlog
,
2819 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2820 num_events
, random_selector
);
2822 event_lp
= iterate_over_lwps (filter
,
2823 select_event_lwp_callback
,
2827 if (event_lp
!= NULL
)
2829 /* Switch the event LWP. */
2830 *orig_lp
= event_lp
;
2831 *status
= event_lp
->status
;
2834 /* Flush the wait status for the event LWP. */
2835 (*orig_lp
)->status
= 0;
2838 /* Return non-zero if LP has been resumed. */
2841 resumed_callback (struct lwp_info
*lp
, void *data
)
2846 /* Stop an active thread, verify it still exists, then resume it. If
2847 the thread ends up with a pending status, then it is not resumed,
2848 and *DATA (really a pointer to int), is set. */
2851 stop_and_resume_callback (struct lwp_info
*lp
, void *data
)
2853 int *new_pending_p
= data
;
2857 ptid_t ptid
= lp
->ptid
;
2859 stop_callback (lp
, NULL
);
2860 stop_wait_callback (lp
, NULL
);
2862 /* Resume if the lwp still exists, and the core wanted it
2864 lp
= find_lwp_pid (ptid
);
2867 if (lp
->last_resume_kind
== resume_stop
2870 /* The core wanted the LWP to stop. Even if it stopped
2871 cleanly (with SIGSTOP), leave the event pending. */
2872 if (debug_linux_nat
)
2873 fprintf_unfiltered (gdb_stdlog
,
2874 "SARC: core wanted LWP %ld stopped "
2875 "(leaving SIGSTOP pending)\n",
2876 ptid_get_lwp (lp
->ptid
));
2877 lp
->status
= W_STOPCODE (SIGSTOP
);
2880 if (lp
->status
== 0)
2882 if (debug_linux_nat
)
2883 fprintf_unfiltered (gdb_stdlog
,
2884 "SARC: re-resuming LWP %ld\n",
2885 ptid_get_lwp (lp
->ptid
));
2886 resume_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2890 if (debug_linux_nat
)
2891 fprintf_unfiltered (gdb_stdlog
,
2892 "SARC: not re-resuming LWP %ld "
2894 ptid_get_lwp (lp
->ptid
));
2903 /* Check if we should go on and pass this event to common code.
2904 Return the affected lwp if we are, or NULL otherwise. If we stop
2905 all lwps temporarily, we may end up with new pending events in some
2906 other lwp. In that case set *NEW_PENDING_P to true. */
2908 static struct lwp_info
*
2909 linux_nat_filter_event (int lwpid
, int status
, int *new_pending_p
)
2911 struct lwp_info
*lp
;
2915 lp
= find_lwp_pid (pid_to_ptid (lwpid
));
2917 /* Check for stop events reported by a process we didn't already
2918 know about - anything not already in our LWP list.
2920 If we're expecting to receive stopped processes after
2921 fork, vfork, and clone events, then we'll just add the
2922 new one to our list and go back to waiting for the event
2923 to be reported - the stopped process might be returned
2924 from waitpid before or after the event is.
2926 But note the case of a non-leader thread exec'ing after the
2927 leader having exited, and gone from our lists. The non-leader
2928 thread changes its tid to the tgid. */
2930 if (WIFSTOPPED (status
) && lp
== NULL
2931 && (WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 == PTRACE_EVENT_EXEC
))
2933 /* A multi-thread exec after we had seen the leader exiting. */
2934 if (debug_linux_nat
)
2935 fprintf_unfiltered (gdb_stdlog
,
2936 "LLW: Re-adding thread group leader LWP %d.\n",
2939 lp
= add_lwp (ptid_build (lwpid
, lwpid
, 0));
2942 add_thread (lp
->ptid
);
2945 if (WIFSTOPPED (status
) && !lp
)
2947 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2951 /* Make sure we don't report an event for the exit of an LWP not in
2952 our list, i.e. not part of the current process. This can happen
2953 if we detach from a program we originally forked and then it
2955 if (!WIFSTOPPED (status
) && !lp
)
2958 /* Handle GNU/Linux's syscall SIGTRAPs. */
2959 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2961 /* No longer need the sysgood bit. The ptrace event ends up
2962 recorded in lp->waitstatus if we care for it. We can carry
2963 on handling the event like a regular SIGTRAP from here
2965 status
= W_STOPCODE (SIGTRAP
);
2966 if (linux_handle_syscall_trap (lp
, 0))
2970 /* Handle GNU/Linux's extended waitstatus for trace events. */
2971 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2973 if (debug_linux_nat
)
2974 fprintf_unfiltered (gdb_stdlog
,
2975 "LLW: Handling extended status 0x%06x\n",
2977 if (linux_handle_extended_wait (lp
, status
, 0))
2981 if (linux_nat_status_is_event (status
))
2984 /* Check if the thread has exited. */
2985 if ((WIFEXITED (status
) || WIFSIGNALED (status
))
2986 && num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
2988 /* If this is the main thread, we must stop all threads and verify
2989 if they are still alive. This is because in the nptl thread model
2990 on Linux 2.4, there is no signal issued for exiting LWPs
2991 other than the main thread. We only get the main thread exit
2992 signal once all child threads have already exited. If we
2993 stop all the threads and use the stop_wait_callback to check
2994 if they have exited we can determine whether this signal
2995 should be ignored or whether it means the end of the debugged
2996 application, regardless of which threading model is being
2998 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
))
3001 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
3002 stop_and_resume_callback
, new_pending_p
);
3005 if (debug_linux_nat
)
3006 fprintf_unfiltered (gdb_stdlog
,
3007 "LLW: %s exited.\n",
3008 target_pid_to_str (lp
->ptid
));
3010 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
3012 /* If there is at least one more LWP, then the exit signal
3013 was not the end of the debugged application and should be
3020 /* Check if the current LWP has previously exited. In the nptl
3021 thread model, LWPs other than the main thread do not issue
3022 signals when they exit so we must check whenever the thread has
3023 stopped. A similar check is made in stop_wait_callback(). */
3024 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1 && !linux_thread_alive (lp
->ptid
))
3026 ptid_t ptid
= pid_to_ptid (ptid_get_pid (lp
->ptid
));
3028 if (debug_linux_nat
)
3029 fprintf_unfiltered (gdb_stdlog
,
3030 "LLW: %s exited.\n",
3031 target_pid_to_str (lp
->ptid
));
3035 /* Make sure there is at least one thread running. */
3036 gdb_assert (iterate_over_lwps (ptid
, running_callback
, NULL
));
3038 /* Discard the event. */
3042 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3043 an attempt to stop an LWP. */
3045 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3047 if (debug_linux_nat
)
3048 fprintf_unfiltered (gdb_stdlog
,
3049 "LLW: Delayed SIGSTOP caught for %s.\n",
3050 target_pid_to_str (lp
->ptid
));
3054 if (lp
->last_resume_kind
!= resume_stop
)
3056 /* This is a delayed SIGSTOP. */
3058 registers_changed ();
3060 if (linux_nat_prepare_to_resume
!= NULL
)
3061 linux_nat_prepare_to_resume (lp
);
3062 linux_ops
->to_resume (linux_ops
,
3063 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3064 lp
->step
, GDB_SIGNAL_0
);
3065 if (debug_linux_nat
)
3066 fprintf_unfiltered (gdb_stdlog
,
3067 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3069 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3070 target_pid_to_str (lp
->ptid
));
3073 gdb_assert (lp
->resumed
);
3075 /* Discard the event. */
3080 /* Make sure we don't report a SIGINT that we have already displayed
3081 for another thread. */
3082 if (lp
->ignore_sigint
3083 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3085 if (debug_linux_nat
)
3086 fprintf_unfiltered (gdb_stdlog
,
3087 "LLW: Delayed SIGINT caught for %s.\n",
3088 target_pid_to_str (lp
->ptid
));
3090 /* This is a delayed SIGINT. */
3091 lp
->ignore_sigint
= 0;
3093 registers_changed ();
3094 if (linux_nat_prepare_to_resume
!= NULL
)
3095 linux_nat_prepare_to_resume (lp
);
3096 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3097 lp
->step
, GDB_SIGNAL_0
);
3098 if (debug_linux_nat
)
3099 fprintf_unfiltered (gdb_stdlog
,
3100 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3102 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3103 target_pid_to_str (lp
->ptid
));
3106 gdb_assert (lp
->resumed
);
3108 /* Discard the event. */
3112 /* An interesting event. */
3114 lp
->status
= status
;
3118 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3119 their exits until all other threads in the group have exited. */
3122 check_zombie_leaders (void)
3124 struct inferior
*inf
;
3128 struct lwp_info
*leader_lp
;
3133 leader_lp
= find_lwp_pid (pid_to_ptid (inf
->pid
));
3134 if (leader_lp
!= NULL
3135 /* Check if there are other threads in the group, as we may
3136 have raced with the inferior simply exiting. */
3137 && num_lwps (inf
->pid
) > 1
3138 && linux_proc_pid_is_zombie (inf
->pid
))
3140 if (debug_linux_nat
)
3141 fprintf_unfiltered (gdb_stdlog
,
3142 "CZL: Thread group leader %d zombie "
3143 "(it exited, or another thread execd).\n",
3146 /* A leader zombie can mean one of two things:
3148 - It exited, and there's an exit status pending
3149 available, or only the leader exited (not the whole
3150 program). In the latter case, we can't waitpid the
3151 leader's exit status until all other threads are gone.
3153 - There are 3 or more threads in the group, and a thread
3154 other than the leader exec'd. On an exec, the Linux
3155 kernel destroys all other threads (except the execing
3156 one) in the thread group, and resets the execing thread's
3157 tid to the tgid. No exit notification is sent for the
3158 execing thread -- from the ptracer's perspective, it
3159 appears as though the execing thread just vanishes.
3160 Until we reap all other threads except the leader and the
3161 execing thread, the leader will be zombie, and the
3162 execing thread will be in `D (disc sleep)'. As soon as
3163 all other threads are reaped, the execing thread changes
3164 it's tid to the tgid, and the previous (zombie) leader
3165 vanishes, giving place to the "new" leader. We could try
3166 distinguishing the exit and exec cases, by waiting once
3167 more, and seeing if something comes out, but it doesn't
3168 sound useful. The previous leader _does_ go away, and
3169 we'll re-add the new one once we see the exec event
3170 (which is just the same as what would happen if the
3171 previous leader did exit voluntarily before some other
3174 if (debug_linux_nat
)
3175 fprintf_unfiltered (gdb_stdlog
,
3176 "CZL: Thread group leader %d vanished.\n",
3178 exit_lwp (leader_lp
);
3184 linux_nat_wait_1 (struct target_ops
*ops
,
3185 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3188 static sigset_t prev_mask
;
3189 enum resume_kind last_resume_kind
;
3190 struct lwp_info
*lp
;
3193 if (debug_linux_nat
)
3194 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3196 /* The first time we get here after starting a new inferior, we may
3197 not have added it to the LWP list yet - this is the earliest
3198 moment at which we know its PID. */
3199 if (ptid_is_pid (inferior_ptid
))
3201 /* Upgrade the main thread's ptid. */
3202 thread_change_ptid (inferior_ptid
,
3203 ptid_build (ptid_get_pid (inferior_ptid
),
3204 ptid_get_pid (inferior_ptid
), 0));
3206 lp
= add_initial_lwp (inferior_ptid
);
3210 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3211 block_child_signals (&prev_mask
);
3217 /* First check if there is a LWP with a wait status pending. */
3218 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3220 /* Any LWP in the PTID group that's been resumed will do. */
3221 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3224 if (debug_linux_nat
&& lp
->status
)
3225 fprintf_unfiltered (gdb_stdlog
,
3226 "LLW: Using pending wait status %s for %s.\n",
3227 status_to_str (lp
->status
),
3228 target_pid_to_str (lp
->ptid
));
3231 else if (ptid_lwp_p (ptid
))
3233 if (debug_linux_nat
)
3234 fprintf_unfiltered (gdb_stdlog
,
3235 "LLW: Waiting for specific LWP %s.\n",
3236 target_pid_to_str (ptid
));
3238 /* We have a specific LWP to check. */
3239 lp
= find_lwp_pid (ptid
);
3242 if (debug_linux_nat
&& lp
->status
)
3243 fprintf_unfiltered (gdb_stdlog
,
3244 "LLW: Using pending wait status %s for %s.\n",
3245 status_to_str (lp
->status
),
3246 target_pid_to_str (lp
->ptid
));
3248 /* We check for lp->waitstatus in addition to lp->status,
3249 because we can have pending process exits recorded in
3250 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3251 an additional lp->status_p flag. */
3252 if (lp
->status
== 0 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3256 if (!target_can_async_p ())
3258 /* Causes SIGINT to be passed on to the attached process. */
3262 /* But if we don't find a pending event, we'll have to wait. */
3268 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3271 - If the thread group leader exits while other threads in the
3272 thread group still exist, waitpid(TGID, ...) hangs. That
3273 waitpid won't return an exit status until the other threads
3274 in the group are reapped.
3276 - When a non-leader thread execs, that thread just vanishes
3277 without reporting an exit (so we'd hang if we waited for it
3278 explicitly in that case). The exec event is reported to
3282 lwpid
= my_waitpid (-1, &status
, __WCLONE
| WNOHANG
);
3283 if (lwpid
== 0 || (lwpid
== -1 && errno
== ECHILD
))
3284 lwpid
= my_waitpid (-1, &status
, WNOHANG
);
3286 if (debug_linux_nat
)
3287 fprintf_unfiltered (gdb_stdlog
,
3288 "LNW: waitpid(-1, ...) returned %d, %s\n",
3289 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3293 /* If this is true, then we paused LWPs momentarily, and may
3294 now have pending events to handle. */
3297 if (debug_linux_nat
)
3299 fprintf_unfiltered (gdb_stdlog
,
3300 "LLW: waitpid %ld received %s\n",
3301 (long) lwpid
, status_to_str (status
));
3304 lp
= linux_nat_filter_event (lwpid
, status
, &new_pending
);
3306 /* STATUS is now no longer valid, use LP->STATUS instead. */
3309 if (lp
&& !ptid_match (lp
->ptid
, ptid
))
3311 gdb_assert (lp
->resumed
);
3313 if (debug_linux_nat
)
3315 "LWP %ld got an event %06x, leaving pending.\n",
3316 ptid_get_lwp (lp
->ptid
), lp
->status
);
3318 if (WIFSTOPPED (lp
->status
))
3320 if (WSTOPSIG (lp
->status
) != SIGSTOP
)
3322 /* Cancel breakpoint hits. The breakpoint may
3323 be removed before we fetch events from this
3324 process to report to the core. It is best
3325 not to assume the moribund breakpoints
3326 heuristic always handles these cases --- it
3327 could be too many events go through to the
3328 core before this one is handled. All-stop
3329 always cancels breakpoint hits in all
3332 && linux_nat_lp_status_is_event (lp
)
3333 && cancel_breakpoint (lp
))
3335 /* Throw away the SIGTRAP. */
3338 if (debug_linux_nat
)
3340 "LLW: LWP %ld hit a breakpoint while"
3341 " waiting for another process;"
3343 ptid_get_lwp (lp
->ptid
));
3353 else if (WIFEXITED (lp
->status
) || WIFSIGNALED (lp
->status
))
3355 if (debug_linux_nat
)
3357 "Process %ld exited while stopping LWPs\n",
3358 ptid_get_lwp (lp
->ptid
));
3360 /* This was the last lwp in the process. Since
3361 events are serialized to GDB core, and we can't
3362 report this one right now, but GDB core and the
3363 other target layers will want to be notified
3364 about the exit code/signal, leave the status
3365 pending for the next time we're able to report
3368 /* Prevent trying to stop this thread again. We'll
3369 never try to resume it because it has a pending
3373 /* Dead LWP's aren't expected to reported a pending
3377 /* Store the pending event in the waitstatus as
3378 well, because W_EXITCODE(0,0) == 0. */
3379 store_waitstatus (&lp
->waitstatus
, lp
->status
);
3388 /* Some LWP now has a pending event. Go all the way
3389 back to check it. */
3395 /* We got an event to report to the core. */
3399 /* Retry until nothing comes out of waitpid. A single
3400 SIGCHLD can indicate more than one child stopped. */
3404 /* Check for zombie thread group leaders. Those can't be reaped
3405 until all other threads in the thread group are. */
3406 check_zombie_leaders ();
3408 /* If there are no resumed children left, bail. We'd be stuck
3409 forever in the sigsuspend call below otherwise. */
3410 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3412 if (debug_linux_nat
)
3413 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3415 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3417 if (!target_can_async_p ())
3418 clear_sigint_trap ();
3420 restore_child_signals_mask (&prev_mask
);
3421 return minus_one_ptid
;
3424 /* No interesting event to report to the core. */
3426 if (target_options
& TARGET_WNOHANG
)
3428 if (debug_linux_nat
)
3429 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3431 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3432 restore_child_signals_mask (&prev_mask
);
3433 return minus_one_ptid
;
3436 /* We shouldn't end up here unless we want to try again. */
3437 gdb_assert (lp
== NULL
);
3439 /* Block until we get an event reported with SIGCHLD. */
3440 sigsuspend (&suspend_mask
);
3443 if (!target_can_async_p ())
3444 clear_sigint_trap ();
3448 status
= lp
->status
;
3451 /* Don't report signals that GDB isn't interested in, such as
3452 signals that are neither printed nor stopped upon. Stopping all
3453 threads can be a bit time-consuming so if we want decent
3454 performance with heavily multi-threaded programs, especially when
3455 they're using a high frequency timer, we'd better avoid it if we
3458 if (WIFSTOPPED (status
))
3460 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3462 /* When using hardware single-step, we need to report every signal.
3463 Otherwise, signals in pass_mask may be short-circuited. */
3465 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
)))
3467 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3468 here? It is not clear we should. GDB may not expect
3469 other threads to run. On the other hand, not resuming
3470 newly attached threads may cause an unwanted delay in
3471 getting them running. */
3472 registers_changed ();
3473 if (linux_nat_prepare_to_resume
!= NULL
)
3474 linux_nat_prepare_to_resume (lp
);
3475 linux_ops
->to_resume (linux_ops
,
3476 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3478 if (debug_linux_nat
)
3479 fprintf_unfiltered (gdb_stdlog
,
3480 "LLW: %s %s, %s (preempt 'handle')\n",
3482 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3483 target_pid_to_str (lp
->ptid
),
3484 (signo
!= GDB_SIGNAL_0
3485 ? strsignal (gdb_signal_to_host (signo
))
3493 /* Only do the below in all-stop, as we currently use SIGINT
3494 to implement target_stop (see linux_nat_stop) in
3496 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3498 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3499 forwarded to the entire process group, that is, all LWPs
3500 will receive it - unless they're using CLONE_THREAD to
3501 share signals. Since we only want to report it once, we
3502 mark it as ignored for all LWPs except this one. */
3503 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid
)),
3504 set_ignore_sigint
, NULL
);
3505 lp
->ignore_sigint
= 0;
3508 maybe_clear_ignore_sigint (lp
);
3512 /* This LWP is stopped now. */
3515 if (debug_linux_nat
)
3516 fprintf_unfiltered (gdb_stdlog
, "LLW: Candidate event %s in %s.\n",
3517 status_to_str (status
), target_pid_to_str (lp
->ptid
));
3521 /* Now stop all other LWP's ... */
3522 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3524 /* ... and wait until all of them have reported back that
3525 they're no longer running. */
3526 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3528 /* If we're not waiting for a specific LWP, choose an event LWP
3529 from among those that have had events. Giving equal priority
3530 to all LWPs that have had events helps prevent
3532 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3533 select_event_lwp (ptid
, &lp
, &status
);
3535 /* Now that we've selected our final event LWP, cancel any
3536 breakpoints in other LWPs that have hit a GDB breakpoint.
3537 See the comment in cancel_breakpoints_callback to find out
3539 iterate_over_lwps (minus_one_ptid
, cancel_breakpoints_callback
, lp
);
3541 /* We'll need this to determine whether to report a SIGSTOP as
3542 TARGET_WAITKIND_0. Need to take a copy because
3543 resume_clear_callback clears it. */
3544 last_resume_kind
= lp
->last_resume_kind
;
3546 /* In all-stop, from the core's perspective, all LWPs are now
3547 stopped until a new resume action is sent over. */
3548 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3553 last_resume_kind
= lp
->last_resume_kind
;
3554 resume_clear_callback (lp
, NULL
);
3557 if (linux_nat_status_is_event (status
))
3559 if (debug_linux_nat
)
3560 fprintf_unfiltered (gdb_stdlog
,
3561 "LLW: trap ptid is %s.\n",
3562 target_pid_to_str (lp
->ptid
));
3565 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3567 *ourstatus
= lp
->waitstatus
;
3568 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3571 store_waitstatus (ourstatus
, status
);
3573 if (debug_linux_nat
)
3574 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3576 restore_child_signals_mask (&prev_mask
);
3578 if (last_resume_kind
== resume_stop
3579 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3580 && WSTOPSIG (status
) == SIGSTOP
)
3582 /* A thread that has been requested to stop by GDB with
3583 target_stop, and it stopped cleanly, so report as SIG0. The
3584 use of SIGSTOP is an implementation detail. */
3585 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3588 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3589 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3592 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3597 /* Resume LWPs that are currently stopped without any pending status
3598 to report, but are resumed from the core's perspective. */
3601 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3603 ptid_t
*wait_ptid_p
= data
;
3608 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3610 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3611 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3612 CORE_ADDR pc
= regcache_read_pc (regcache
);
3614 gdb_assert (is_executing (lp
->ptid
));
3616 /* Don't bother if there's a breakpoint at PC that we'd hit
3617 immediately, and we're not waiting for this LWP. */
3618 if (!ptid_match (lp
->ptid
, *wait_ptid_p
))
3620 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
3624 if (debug_linux_nat
)
3625 fprintf_unfiltered (gdb_stdlog
,
3626 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3627 target_pid_to_str (lp
->ptid
),
3628 paddress (gdbarch
, pc
),
3631 registers_changed ();
3632 if (linux_nat_prepare_to_resume
!= NULL
)
3633 linux_nat_prepare_to_resume (lp
);
3634 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3635 lp
->step
, GDB_SIGNAL_0
);
3637 lp
->stopped_by_watchpoint
= 0;
3644 linux_nat_wait (struct target_ops
*ops
,
3645 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3650 if (debug_linux_nat
)
3652 char *options_string
;
3654 options_string
= target_options_to_string (target_options
);
3655 fprintf_unfiltered (gdb_stdlog
,
3656 "linux_nat_wait: [%s], [%s]\n",
3657 target_pid_to_str (ptid
),
3659 xfree (options_string
);
3662 /* Flush the async file first. */
3663 if (target_can_async_p ())
3664 async_file_flush ();
3666 /* Resume LWPs that are currently stopped without any pending status
3667 to report, but are resumed from the core's perspective. LWPs get
3668 in this state if we find them stopping at a time we're not
3669 interested in reporting the event (target_wait on a
3670 specific_process, for example, see linux_nat_wait_1), and
3671 meanwhile the event became uninteresting. Don't bother resuming
3672 LWPs we're not going to wait for if they'd stop immediately. */
3674 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3676 event_ptid
= linux_nat_wait_1 (ops
, ptid
, ourstatus
, target_options
);
3678 /* If we requested any event, and something came out, assume there
3679 may be more. If we requested a specific lwp or process, also
3680 assume there may be more. */
3681 if (target_can_async_p ()
3682 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3683 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3684 || !ptid_equal (ptid
, minus_one_ptid
)))
3687 /* Get ready for the next event. */
3688 if (target_can_async_p ())
3689 target_async (inferior_event_handler
, 0);
3695 kill_callback (struct lwp_info
*lp
, void *data
)
3697 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3700 kill (ptid_get_lwp (lp
->ptid
), SIGKILL
);
3701 if (debug_linux_nat
)
3702 fprintf_unfiltered (gdb_stdlog
,
3703 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3704 target_pid_to_str (lp
->ptid
),
3705 errno
? safe_strerror (errno
) : "OK");
3707 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3710 ptrace (PTRACE_KILL
, ptid_get_lwp (lp
->ptid
), 0, 0);
3711 if (debug_linux_nat
)
3712 fprintf_unfiltered (gdb_stdlog
,
3713 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3714 target_pid_to_str (lp
->ptid
),
3715 errno
? safe_strerror (errno
) : "OK");
3721 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3725 /* We must make sure that there are no pending events (delayed
3726 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3727 program doesn't interfere with any following debugging session. */
3729 /* For cloned processes we must check both with __WCLONE and
3730 without, since the exit status of a cloned process isn't reported
3736 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, __WCLONE
);
3737 if (pid
!= (pid_t
) -1)
3739 if (debug_linux_nat
)
3740 fprintf_unfiltered (gdb_stdlog
,
3741 "KWC: wait %s received unknown.\n",
3742 target_pid_to_str (lp
->ptid
));
3743 /* The Linux kernel sometimes fails to kill a thread
3744 completely after PTRACE_KILL; that goes from the stop
3745 point in do_fork out to the one in
3746 get_signal_to_deliever and waits again. So kill it
3748 kill_callback (lp
, NULL
);
3751 while (pid
== ptid_get_lwp (lp
->ptid
));
3753 gdb_assert (pid
== -1 && errno
== ECHILD
);
3758 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, 0);
3759 if (pid
!= (pid_t
) -1)
3761 if (debug_linux_nat
)
3762 fprintf_unfiltered (gdb_stdlog
,
3763 "KWC: wait %s received unk.\n",
3764 target_pid_to_str (lp
->ptid
));
3765 /* See the call to kill_callback above. */
3766 kill_callback (lp
, NULL
);
3769 while (pid
== ptid_get_lwp (lp
->ptid
));
3771 gdb_assert (pid
== -1 && errno
== ECHILD
);
3776 linux_nat_kill (struct target_ops
*ops
)
3778 struct target_waitstatus last
;
3782 /* If we're stopped while forking and we haven't followed yet,
3783 kill the other task. We need to do this first because the
3784 parent will be sleeping if this is a vfork. */
3786 get_last_target_status (&last_ptid
, &last
);
3788 if (last
.kind
== TARGET_WAITKIND_FORKED
3789 || last
.kind
== TARGET_WAITKIND_VFORKED
)
3791 ptrace (PT_KILL
, ptid_get_pid (last
.value
.related_pid
), 0, 0);
3794 /* Let the arch-specific native code know this process is
3796 linux_nat_forget_process (ptid_get_pid (last
.value
.related_pid
));
3799 if (forks_exist_p ())
3800 linux_fork_killall ();
3803 ptid_t ptid
= pid_to_ptid (ptid_get_pid (inferior_ptid
));
3805 /* Stop all threads before killing them, since ptrace requires
3806 that the thread is stopped to sucessfully PTRACE_KILL. */
3807 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3808 /* ... and wait until all of them have reported back that
3809 they're no longer running. */
3810 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3812 /* Kill all LWP's ... */
3813 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3815 /* ... and wait until we've flushed all events. */
3816 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3819 target_mourn_inferior ();
3823 linux_nat_mourn_inferior (struct target_ops
*ops
)
3825 int pid
= ptid_get_pid (inferior_ptid
);
3827 purge_lwp_list (pid
);
3829 if (! forks_exist_p ())
3830 /* Normal case, no other forks available. */
3831 linux_ops
->to_mourn_inferior (ops
);
3833 /* Multi-fork case. The current inferior_ptid has exited, but
3834 there are other viable forks to debug. Delete the exiting
3835 one and context-switch to the first available. */
3836 linux_fork_mourn_inferior ();
3838 /* Let the arch-specific native code know this process is gone. */
3839 linux_nat_forget_process (pid
);
3842 /* Convert a native/host siginfo object, into/from the siginfo in the
3843 layout of the inferiors' architecture. */
3846 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3850 if (linux_nat_siginfo_fixup
!= NULL
)
3851 done
= linux_nat_siginfo_fixup (siginfo
, inf_siginfo
, direction
);
3853 /* If there was no callback, or the callback didn't do anything,
3854 then just do a straight memcpy. */
3858 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3860 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3864 static enum target_xfer_status
3865 linux_xfer_siginfo (struct target_ops
*ops
, enum target_object object
,
3866 const char *annex
, gdb_byte
*readbuf
,
3867 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3868 ULONGEST
*xfered_len
)
3872 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3874 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3875 gdb_assert (readbuf
|| writebuf
);
3877 pid
= ptid_get_lwp (inferior_ptid
);
3879 pid
= ptid_get_pid (inferior_ptid
);
3881 if (offset
> sizeof (siginfo
))
3882 return TARGET_XFER_E_IO
;
3885 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3887 return TARGET_XFER_E_IO
;
3889 /* When GDB is built as a 64-bit application, ptrace writes into
3890 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3891 inferior with a 64-bit GDB should look the same as debugging it
3892 with a 32-bit GDB, we need to convert it. GDB core always sees
3893 the converted layout, so any read/write will have to be done
3895 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3897 if (offset
+ len
> sizeof (siginfo
))
3898 len
= sizeof (siginfo
) - offset
;
3900 if (readbuf
!= NULL
)
3901 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3904 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3906 /* Convert back to ptrace layout before flushing it out. */
3907 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3910 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3912 return TARGET_XFER_E_IO
;
3916 return TARGET_XFER_OK
;
3919 static enum target_xfer_status
3920 linux_nat_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3921 const char *annex
, gdb_byte
*readbuf
,
3922 const gdb_byte
*writebuf
,
3923 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3925 struct cleanup
*old_chain
;
3926 enum target_xfer_status xfer
;
3928 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3929 return linux_xfer_siginfo (ops
, object
, annex
, readbuf
, writebuf
,
3930 offset
, len
, xfered_len
);
3932 /* The target is connected but no live inferior is selected. Pass
3933 this request down to a lower stratum (e.g., the executable
3935 if (object
== TARGET_OBJECT_MEMORY
&& ptid_equal (inferior_ptid
, null_ptid
))
3936 return TARGET_XFER_EOF
;
3938 old_chain
= save_inferior_ptid ();
3940 if (ptid_lwp_p (inferior_ptid
))
3941 inferior_ptid
= pid_to_ptid (ptid_get_lwp (inferior_ptid
));
3943 xfer
= linux_ops
->to_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
3944 offset
, len
, xfered_len
);
3946 do_cleanups (old_chain
);
3951 linux_thread_alive (ptid_t ptid
)
3955 gdb_assert (ptid_lwp_p (ptid
));
3957 /* Send signal 0 instead of anything ptrace, because ptracing a
3958 running thread errors out claiming that the thread doesn't
3960 err
= kill_lwp (ptid_get_lwp (ptid
), 0);
3962 if (debug_linux_nat
)
3963 fprintf_unfiltered (gdb_stdlog
,
3964 "LLTA: KILL(SIG0) %s (%s)\n",
3965 target_pid_to_str (ptid
),
3966 err
? safe_strerror (tmp_errno
) : "OK");
3975 linux_nat_thread_alive (struct target_ops
*ops
, ptid_t ptid
)
3977 return linux_thread_alive (ptid
);
3981 linux_nat_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
3983 static char buf
[64];
3985 if (ptid_lwp_p (ptid
)
3986 && (ptid_get_pid (ptid
) != ptid_get_lwp (ptid
)
3987 || num_lwps (ptid_get_pid (ptid
)) > 1))
3989 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid_get_lwp (ptid
));
3993 return normal_pid_to_str (ptid
);
3997 linux_nat_thread_name (struct target_ops
*self
, struct thread_info
*thr
)
3999 int pid
= ptid_get_pid (thr
->ptid
);
4000 long lwp
= ptid_get_lwp (thr
->ptid
);
4001 #define FORMAT "/proc/%d/task/%ld/comm"
4002 char buf
[sizeof (FORMAT
) + 30];
4004 char *result
= NULL
;
4006 snprintf (buf
, sizeof (buf
), FORMAT
, pid
, lwp
);
4007 comm_file
= gdb_fopen_cloexec (buf
, "r");
4010 /* Not exported by the kernel, so we define it here. */
4012 static char line
[COMM_LEN
+ 1];
4014 if (fgets (line
, sizeof (line
), comm_file
))
4016 char *nl
= strchr (line
, '\n');
4033 /* Accepts an integer PID; Returns a string representing a file that
4034 can be opened to get the symbols for the child process. */
4037 linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
)
4039 char *name1
, *name2
;
4041 name1
= xmalloc (PATH_MAX
);
4042 name2
= xmalloc (PATH_MAX
);
4043 make_cleanup (xfree
, name1
);
4044 make_cleanup (xfree
, name2
);
4045 memset (name2
, 0, PATH_MAX
);
4047 xsnprintf (name1
, PATH_MAX
, "/proc/%d/exe", pid
);
4048 if (readlink (name1
, name2
, PATH_MAX
- 1) > 0)
4054 /* Records the thread's register state for the corefile note
4058 linux_nat_collect_thread_registers (const struct regcache
*regcache
,
4059 ptid_t ptid
, bfd
*obfd
,
4060 char *note_data
, int *note_size
,
4061 enum gdb_signal stop_signal
)
4063 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
4064 const struct regset
*regset
;
4066 gdb_gregset_t gregs
;
4067 gdb_fpregset_t fpregs
;
4069 core_regset_p
= gdbarch_regset_from_core_section_p (gdbarch
);
4072 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg",
4074 != NULL
&& regset
->collect_regset
!= NULL
)
4075 regset
->collect_regset (regset
, regcache
, -1, &gregs
, sizeof (gregs
));
4077 fill_gregset (regcache
, &gregs
, -1);
4079 note_data
= (char *) elfcore_write_prstatus
4080 (obfd
, note_data
, note_size
, ptid_get_lwp (ptid
),
4081 gdb_signal_to_host (stop_signal
), &gregs
);
4084 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg2",
4086 != NULL
&& regset
->collect_regset
!= NULL
)
4087 regset
->collect_regset (regset
, regcache
, -1, &fpregs
, sizeof (fpregs
));
4089 fill_fpregset (regcache
, &fpregs
, -1);
4091 note_data
= (char *) elfcore_write_prfpreg (obfd
, note_data
, note_size
,
4092 &fpregs
, sizeof (fpregs
));
4097 /* Fills the "to_make_corefile_note" target vector. Builds the note
4098 section for a corefile, and returns it in a malloc buffer. */
4101 linux_nat_make_corefile_notes (struct target_ops
*self
,
4102 bfd
*obfd
, int *note_size
)
4104 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4105 converted to gdbarch_core_regset_sections, this function can go away. */
4106 return linux_make_corefile_notes (target_gdbarch (), obfd
, note_size
,
4107 linux_nat_collect_thread_registers
);
4110 /* Implement the to_xfer_partial interface for memory reads using the /proc
4111 filesystem. Because we can use a single read() call for /proc, this
4112 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4113 but it doesn't support writes. */
4115 static enum target_xfer_status
4116 linux_proc_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4117 const char *annex
, gdb_byte
*readbuf
,
4118 const gdb_byte
*writebuf
,
4119 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
4125 if (object
!= TARGET_OBJECT_MEMORY
|| !readbuf
)
4128 /* Don't bother for one word. */
4129 if (len
< 3 * sizeof (long))
4130 return TARGET_XFER_EOF
;
4132 /* We could keep this file open and cache it - possibly one per
4133 thread. That requires some juggling, but is even faster. */
4134 xsnprintf (filename
, sizeof filename
, "/proc/%d/mem",
4135 ptid_get_pid (inferior_ptid
));
4136 fd
= gdb_open_cloexec (filename
, O_RDONLY
| O_LARGEFILE
, 0);
4138 return TARGET_XFER_EOF
;
4140 /* If pread64 is available, use it. It's faster if the kernel
4141 supports it (only one syscall), and it's 64-bit safe even on
4142 32-bit platforms (for instance, SPARC debugging a SPARC64
4145 if (pread64 (fd
, readbuf
, len
, offset
) != len
)
4147 if (lseek (fd
, offset
, SEEK_SET
) == -1 || read (fd
, readbuf
, len
) != len
)
4156 return TARGET_XFER_EOF
;
4160 return TARGET_XFER_OK
;
4165 /* Enumerate spufs IDs for process PID. */
4167 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
4169 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
4171 LONGEST written
= 0;
4174 struct dirent
*entry
;
4176 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
4177 dir
= opendir (path
);
4182 while ((entry
= readdir (dir
)) != NULL
)
4188 fd
= atoi (entry
->d_name
);
4192 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
4193 if (stat (path
, &st
) != 0)
4195 if (!S_ISDIR (st
.st_mode
))
4198 if (statfs (path
, &stfs
) != 0)
4200 if (stfs
.f_type
!= SPUFS_MAGIC
)
4203 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
4205 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
4215 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4216 object type, using the /proc file system. */
4218 static enum target_xfer_status
4219 linux_proc_xfer_spu (struct target_ops
*ops
, enum target_object object
,
4220 const char *annex
, gdb_byte
*readbuf
,
4221 const gdb_byte
*writebuf
,
4222 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
4227 int pid
= ptid_get_pid (inferior_ptid
);
4232 return TARGET_XFER_E_IO
;
4235 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4238 return TARGET_XFER_E_IO
;
4240 return TARGET_XFER_EOF
;
4243 *xfered_len
= (ULONGEST
) l
;
4244 return TARGET_XFER_OK
;
4249 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4250 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4252 return TARGET_XFER_E_IO
;
4255 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4258 return TARGET_XFER_EOF
;
4262 ret
= write (fd
, writebuf
, (size_t) len
);
4264 ret
= read (fd
, readbuf
, (size_t) len
);
4269 return TARGET_XFER_E_IO
;
4271 return TARGET_XFER_EOF
;
4274 *xfered_len
= (ULONGEST
) ret
;
4275 return TARGET_XFER_OK
;
4280 /* Parse LINE as a signal set and add its set bits to SIGS. */
4283 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4285 int len
= strlen (line
) - 1;
4289 if (line
[len
] != '\n')
4290 error (_("Could not parse signal set: %s"), line
);
4298 if (*p
>= '0' && *p
<= '9')
4300 else if (*p
>= 'a' && *p
<= 'f')
4301 digit
= *p
- 'a' + 10;
4303 error (_("Could not parse signal set: %s"), line
);
4308 sigaddset (sigs
, signum
+ 1);
4310 sigaddset (sigs
, signum
+ 2);
4312 sigaddset (sigs
, signum
+ 3);
4314 sigaddset (sigs
, signum
+ 4);
4320 /* Find process PID's pending signals from /proc/pid/status and set
4324 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4325 sigset_t
*blocked
, sigset_t
*ignored
)
4328 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4329 struct cleanup
*cleanup
;
4331 sigemptyset (pending
);
4332 sigemptyset (blocked
);
4333 sigemptyset (ignored
);
4334 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4335 procfile
= gdb_fopen_cloexec (fname
, "r");
4336 if (procfile
== NULL
)
4337 error (_("Could not open %s"), fname
);
4338 cleanup
= make_cleanup_fclose (procfile
);
4340 while (fgets (buffer
, PATH_MAX
, procfile
) != NULL
)
4342 /* Normal queued signals are on the SigPnd line in the status
4343 file. However, 2.6 kernels also have a "shared" pending
4344 queue for delivering signals to a thread group, so check for
4347 Unfortunately some Red Hat kernels include the shared pending
4348 queue but not the ShdPnd status field. */
4350 if (strncmp (buffer
, "SigPnd:\t", 8) == 0)
4351 add_line_to_sigset (buffer
+ 8, pending
);
4352 else if (strncmp (buffer
, "ShdPnd:\t", 8) == 0)
4353 add_line_to_sigset (buffer
+ 8, pending
);
4354 else if (strncmp (buffer
, "SigBlk:\t", 8) == 0)
4355 add_line_to_sigset (buffer
+ 8, blocked
);
4356 else if (strncmp (buffer
, "SigIgn:\t", 8) == 0)
4357 add_line_to_sigset (buffer
+ 8, ignored
);
4360 do_cleanups (cleanup
);
4363 static enum target_xfer_status
4364 linux_nat_xfer_osdata (struct target_ops
*ops
, enum target_object object
,
4365 const char *annex
, gdb_byte
*readbuf
,
4366 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4367 ULONGEST
*xfered_len
)
4369 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4371 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4372 if (*xfered_len
== 0)
4373 return TARGET_XFER_EOF
;
4375 return TARGET_XFER_OK
;
4378 static enum target_xfer_status
4379 linux_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4380 const char *annex
, gdb_byte
*readbuf
,
4381 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4382 ULONGEST
*xfered_len
)
4384 enum target_xfer_status xfer
;
4386 if (object
== TARGET_OBJECT_AUXV
)
4387 return memory_xfer_auxv (ops
, object
, annex
, readbuf
, writebuf
,
4388 offset
, len
, xfered_len
);
4390 if (object
== TARGET_OBJECT_OSDATA
)
4391 return linux_nat_xfer_osdata (ops
, object
, annex
, readbuf
, writebuf
,
4392 offset
, len
, xfered_len
);
4394 if (object
== TARGET_OBJECT_SPU
)
4395 return linux_proc_xfer_spu (ops
, object
, annex
, readbuf
, writebuf
,
4396 offset
, len
, xfered_len
);
4398 /* GDB calculates all the addresses in possibly larget width of the address.
4399 Address width needs to be masked before its final use - either by
4400 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4402 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4404 if (object
== TARGET_OBJECT_MEMORY
)
4406 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
4408 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
4409 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
4412 xfer
= linux_proc_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4413 offset
, len
, xfered_len
);
4414 if (xfer
!= TARGET_XFER_EOF
)
4417 return super_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4418 offset
, len
, xfered_len
);
4422 cleanup_target_stop (void *arg
)
4424 ptid_t
*ptid
= (ptid_t
*) arg
;
4426 gdb_assert (arg
!= NULL
);
4429 target_resume (*ptid
, 0, GDB_SIGNAL_0
);
4432 static VEC(static_tracepoint_marker_p
) *
4433 linux_child_static_tracepoint_markers_by_strid (struct target_ops
*self
,
4436 char s
[IPA_CMD_BUF_SIZE
];
4437 struct cleanup
*old_chain
;
4438 int pid
= ptid_get_pid (inferior_ptid
);
4439 VEC(static_tracepoint_marker_p
) *markers
= NULL
;
4440 struct static_tracepoint_marker
*marker
= NULL
;
4442 ptid_t ptid
= ptid_build (pid
, 0, 0);
4447 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4448 s
[sizeof ("qTfSTM")] = 0;
4450 agent_run_command (pid
, s
, strlen (s
) + 1);
4452 old_chain
= make_cleanup (free_current_marker
, &marker
);
4453 make_cleanup (cleanup_target_stop
, &ptid
);
4458 marker
= XCNEW (struct static_tracepoint_marker
);
4462 parse_static_tracepoint_marker_definition (p
, &p
, marker
);
4464 if (strid
== NULL
|| strcmp (strid
, marker
->str_id
) == 0)
4466 VEC_safe_push (static_tracepoint_marker_p
,
4472 release_static_tracepoint_marker (marker
);
4473 memset (marker
, 0, sizeof (*marker
));
4476 while (*p
++ == ','); /* comma-separated list */
4478 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4479 s
[sizeof ("qTsSTM")] = 0;
4480 agent_run_command (pid
, s
, strlen (s
) + 1);
4484 do_cleanups (old_chain
);
4489 /* Create a prototype generic GNU/Linux target. The client can override
4490 it with local methods. */
4493 linux_target_install_ops (struct target_ops
*t
)
4495 t
->to_insert_fork_catchpoint
= linux_child_insert_fork_catchpoint
;
4496 t
->to_remove_fork_catchpoint
= linux_child_remove_fork_catchpoint
;
4497 t
->to_insert_vfork_catchpoint
= linux_child_insert_vfork_catchpoint
;
4498 t
->to_remove_vfork_catchpoint
= linux_child_remove_vfork_catchpoint
;
4499 t
->to_insert_exec_catchpoint
= linux_child_insert_exec_catchpoint
;
4500 t
->to_remove_exec_catchpoint
= linux_child_remove_exec_catchpoint
;
4501 t
->to_set_syscall_catchpoint
= linux_child_set_syscall_catchpoint
;
4502 t
->to_pid_to_exec_file
= linux_child_pid_to_exec_file
;
4503 t
->to_post_startup_inferior
= linux_child_post_startup_inferior
;
4504 t
->to_post_attach
= linux_child_post_attach
;
4505 t
->to_follow_fork
= linux_child_follow_fork
;
4506 t
->to_make_corefile_notes
= linux_nat_make_corefile_notes
;
4508 super_xfer_partial
= t
->to_xfer_partial
;
4509 t
->to_xfer_partial
= linux_xfer_partial
;
4511 t
->to_static_tracepoint_markers_by_strid
4512 = linux_child_static_tracepoint_markers_by_strid
;
4518 struct target_ops
*t
;
4520 t
= inf_ptrace_target ();
4521 linux_target_install_ops (t
);
4527 linux_trad_target (CORE_ADDR (*register_u_offset
)(struct gdbarch
*, int, int))
4529 struct target_ops
*t
;
4531 t
= inf_ptrace_trad_target (register_u_offset
);
4532 linux_target_install_ops (t
);
4537 /* target_is_async_p implementation. */
4540 linux_nat_is_async_p (struct target_ops
*ops
)
4542 /* NOTE: palves 2008-03-21: We're only async when the user requests
4543 it explicitly with the "set target-async" command.
4544 Someday, linux will always be async. */
4545 return target_async_permitted
;
4548 /* target_can_async_p implementation. */
4551 linux_nat_can_async_p (struct target_ops
*ops
)
4553 /* NOTE: palves 2008-03-21: We're only async when the user requests
4554 it explicitly with the "set target-async" command.
4555 Someday, linux will always be async. */
4556 return target_async_permitted
;
4560 linux_nat_supports_non_stop (struct target_ops
*self
)
4565 /* True if we want to support multi-process. To be removed when GDB
4566 supports multi-exec. */
4568 int linux_multi_process
= 1;
4571 linux_nat_supports_multi_process (struct target_ops
*self
)
4573 return linux_multi_process
;
4577 linux_nat_supports_disable_randomization (struct target_ops
*self
)
4579 #ifdef HAVE_PERSONALITY
4586 static int async_terminal_is_ours
= 1;
4588 /* target_terminal_inferior implementation. */
4591 linux_nat_terminal_inferior (struct target_ops
*self
)
4593 if (!target_is_async_p ())
4595 /* Async mode is disabled. */
4596 terminal_inferior (self
);
4600 terminal_inferior (self
);
4602 /* Calls to target_terminal_*() are meant to be idempotent. */
4603 if (!async_terminal_is_ours
)
4606 delete_file_handler (input_fd
);
4607 async_terminal_is_ours
= 0;
4611 /* target_terminal_ours implementation. */
4614 linux_nat_terminal_ours (struct target_ops
*self
)
4616 if (!target_is_async_p ())
4618 /* Async mode is disabled. */
4619 terminal_ours (self
);
4623 /* GDB should never give the terminal to the inferior if the
4624 inferior is running in the background (run&, continue&, etc.),
4625 but claiming it sure should. */
4626 terminal_ours (self
);
4628 if (async_terminal_is_ours
)
4631 clear_sigint_trap ();
4632 add_file_handler (input_fd
, stdin_event_handler
, 0);
4633 async_terminal_is_ours
= 1;
4636 static void (*async_client_callback
) (enum inferior_event_type event_type
,
4638 static void *async_client_context
;
4640 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4641 so we notice when any child changes state, and notify the
4642 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4643 above to wait for the arrival of a SIGCHLD. */
4646 sigchld_handler (int signo
)
4648 int old_errno
= errno
;
4650 if (debug_linux_nat
)
4651 ui_file_write_async_safe (gdb_stdlog
,
4652 "sigchld\n", sizeof ("sigchld\n") - 1);
4654 if (signo
== SIGCHLD
4655 && linux_nat_event_pipe
[0] != -1)
4656 async_file_mark (); /* Let the event loop know that there are
4657 events to handle. */
4662 /* Callback registered with the target events file descriptor. */
4665 handle_target_event (int error
, gdb_client_data client_data
)
4667 (*async_client_callback
) (INF_REG_EVENT
, async_client_context
);
4670 /* Create/destroy the target events pipe. Returns previous state. */
4673 linux_async_pipe (int enable
)
4675 int previous
= (linux_nat_event_pipe
[0] != -1);
4677 if (previous
!= enable
)
4681 /* Block child signals while we create/destroy the pipe, as
4682 their handler writes to it. */
4683 block_child_signals (&prev_mask
);
4687 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4688 internal_error (__FILE__
, __LINE__
,
4689 "creating event pipe failed.");
4691 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4692 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4696 close (linux_nat_event_pipe
[0]);
4697 close (linux_nat_event_pipe
[1]);
4698 linux_nat_event_pipe
[0] = -1;
4699 linux_nat_event_pipe
[1] = -1;
4702 restore_child_signals_mask (&prev_mask
);
4708 /* target_async implementation. */
4711 linux_nat_async (struct target_ops
*ops
,
4712 void (*callback
) (enum inferior_event_type event_type
,
4716 if (callback
!= NULL
)
4718 async_client_callback
= callback
;
4719 async_client_context
= context
;
4720 if (!linux_async_pipe (1))
4722 add_file_handler (linux_nat_event_pipe
[0],
4723 handle_target_event
, NULL
);
4724 /* There may be pending events to handle. Tell the event loop
4731 async_client_callback
= callback
;
4732 async_client_context
= context
;
4733 delete_file_handler (linux_nat_event_pipe
[0]);
4734 linux_async_pipe (0);
4739 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4743 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4747 if (debug_linux_nat
)
4748 fprintf_unfiltered (gdb_stdlog
,
4749 "LNSL: running -> suspending %s\n",
4750 target_pid_to_str (lwp
->ptid
));
4753 if (lwp
->last_resume_kind
== resume_stop
)
4755 if (debug_linux_nat
)
4756 fprintf_unfiltered (gdb_stdlog
,
4757 "linux-nat: already stopping LWP %ld at "
4759 ptid_get_lwp (lwp
->ptid
));
4763 stop_callback (lwp
, NULL
);
4764 lwp
->last_resume_kind
= resume_stop
;
4768 /* Already known to be stopped; do nothing. */
4770 if (debug_linux_nat
)
4772 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4773 fprintf_unfiltered (gdb_stdlog
,
4774 "LNSL: already stopped/stop_requested %s\n",
4775 target_pid_to_str (lwp
->ptid
));
4777 fprintf_unfiltered (gdb_stdlog
,
4778 "LNSL: already stopped/no "
4779 "stop_requested yet %s\n",
4780 target_pid_to_str (lwp
->ptid
));
4787 linux_nat_stop (struct target_ops
*self
, ptid_t ptid
)
4790 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4792 linux_ops
->to_stop (linux_ops
, ptid
);
4796 linux_nat_close (struct target_ops
*self
)
4798 /* Unregister from the event loop. */
4799 if (linux_nat_is_async_p (NULL
))
4800 linux_nat_async (NULL
, NULL
, 0);
4802 if (linux_ops
->to_close
)
4803 linux_ops
->to_close (linux_ops
);
4806 /* When requests are passed down from the linux-nat layer to the
4807 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4808 used. The address space pointer is stored in the inferior object,
4809 but the common code that is passed such ptid can't tell whether
4810 lwpid is a "main" process id or not (it assumes so). We reverse
4811 look up the "main" process id from the lwp here. */
4813 static struct address_space
*
4814 linux_nat_thread_address_space (struct target_ops
*t
, ptid_t ptid
)
4816 struct lwp_info
*lwp
;
4817 struct inferior
*inf
;
4820 pid
= ptid_get_lwp (ptid
);
4821 if (ptid_get_lwp (ptid
) == 0)
4823 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4825 lwp
= find_lwp_pid (ptid
);
4826 pid
= ptid_get_pid (lwp
->ptid
);
4830 /* A (pid,lwpid,0) ptid. */
4831 pid
= ptid_get_pid (ptid
);
4834 inf
= find_inferior_pid (pid
);
4835 gdb_assert (inf
!= NULL
);
4839 /* Return the cached value of the processor core for thread PTID. */
4842 linux_nat_core_of_thread (struct target_ops
*ops
, ptid_t ptid
)
4844 struct lwp_info
*info
= find_lwp_pid (ptid
);
4852 linux_nat_add_target (struct target_ops
*t
)
4854 /* Save the provided single-threaded target. We save this in a separate
4855 variable because another target we've inherited from (e.g. inf-ptrace)
4856 may have saved a pointer to T; we want to use it for the final
4857 process stratum target. */
4858 linux_ops_saved
= *t
;
4859 linux_ops
= &linux_ops_saved
;
4861 /* Override some methods for multithreading. */
4862 t
->to_create_inferior
= linux_nat_create_inferior
;
4863 t
->to_attach
= linux_nat_attach
;
4864 t
->to_detach
= linux_nat_detach
;
4865 t
->to_resume
= linux_nat_resume
;
4866 t
->to_wait
= linux_nat_wait
;
4867 t
->to_pass_signals
= linux_nat_pass_signals
;
4868 t
->to_xfer_partial
= linux_nat_xfer_partial
;
4869 t
->to_kill
= linux_nat_kill
;
4870 t
->to_mourn_inferior
= linux_nat_mourn_inferior
;
4871 t
->to_thread_alive
= linux_nat_thread_alive
;
4872 t
->to_pid_to_str
= linux_nat_pid_to_str
;
4873 t
->to_thread_name
= linux_nat_thread_name
;
4874 t
->to_has_thread_control
= tc_schedlock
;
4875 t
->to_thread_address_space
= linux_nat_thread_address_space
;
4876 t
->to_stopped_by_watchpoint
= linux_nat_stopped_by_watchpoint
;
4877 t
->to_stopped_data_address
= linux_nat_stopped_data_address
;
4879 t
->to_can_async_p
= linux_nat_can_async_p
;
4880 t
->to_is_async_p
= linux_nat_is_async_p
;
4881 t
->to_supports_non_stop
= linux_nat_supports_non_stop
;
4882 t
->to_async
= linux_nat_async
;
4883 t
->to_terminal_inferior
= linux_nat_terminal_inferior
;
4884 t
->to_terminal_ours
= linux_nat_terminal_ours
;
4885 t
->to_close
= linux_nat_close
;
4887 /* Methods for non-stop support. */
4888 t
->to_stop
= linux_nat_stop
;
4890 t
->to_supports_multi_process
= linux_nat_supports_multi_process
;
4892 t
->to_supports_disable_randomization
4893 = linux_nat_supports_disable_randomization
;
4895 t
->to_core_of_thread
= linux_nat_core_of_thread
;
4897 /* We don't change the stratum; this target will sit at
4898 process_stratum and thread_db will set at thread_stratum. This
4899 is a little strange, since this is a multi-threaded-capable
4900 target, but we want to be on the stack below thread_db, and we
4901 also want to be used for single-threaded processes. */
4906 /* Register a method to call whenever a new thread is attached. */
4908 linux_nat_set_new_thread (struct target_ops
*t
,
4909 void (*new_thread
) (struct lwp_info
*))
4911 /* Save the pointer. We only support a single registered instance
4912 of the GNU/Linux native target, so we do not need to map this to
4914 linux_nat_new_thread
= new_thread
;
4917 /* See declaration in linux-nat.h. */
4920 linux_nat_set_new_fork (struct target_ops
*t
,
4921 linux_nat_new_fork_ftype
*new_fork
)
4923 /* Save the pointer. */
4924 linux_nat_new_fork
= new_fork
;
4927 /* See declaration in linux-nat.h. */
4930 linux_nat_set_forget_process (struct target_ops
*t
,
4931 linux_nat_forget_process_ftype
*fn
)
4933 /* Save the pointer. */
4934 linux_nat_forget_process_hook
= fn
;
4937 /* See declaration in linux-nat.h. */
4940 linux_nat_forget_process (pid_t pid
)
4942 if (linux_nat_forget_process_hook
!= NULL
)
4943 linux_nat_forget_process_hook (pid
);
4946 /* Register a method that converts a siginfo object between the layout
4947 that ptrace returns, and the layout in the architecture of the
4950 linux_nat_set_siginfo_fixup (struct target_ops
*t
,
4951 int (*siginfo_fixup
) (siginfo_t
*,
4955 /* Save the pointer. */
4956 linux_nat_siginfo_fixup
= siginfo_fixup
;
4959 /* Register a method to call prior to resuming a thread. */
4962 linux_nat_set_prepare_to_resume (struct target_ops
*t
,
4963 void (*prepare_to_resume
) (struct lwp_info
*))
4965 /* Save the pointer. */
4966 linux_nat_prepare_to_resume
= prepare_to_resume
;
4969 /* See linux-nat.h. */
4972 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4976 pid
= ptid_get_lwp (ptid
);
4978 pid
= ptid_get_pid (ptid
);
4981 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4984 memset (siginfo
, 0, sizeof (*siginfo
));
4990 /* Provide a prototype to silence -Wmissing-prototypes. */
4991 extern initialize_file_ftype _initialize_linux_nat
;
4994 _initialize_linux_nat (void)
4996 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4997 &debug_linux_nat
, _("\
4998 Set debugging of GNU/Linux lwp module."), _("\
4999 Show debugging of GNU/Linux lwp module."), _("\
5000 Enables printf debugging output."),
5002 show_debug_linux_nat
,
5003 &setdebuglist
, &showdebuglist
);
5005 /* Save this mask as the default. */
5006 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
5008 /* Install a SIGCHLD handler. */
5009 sigchld_action
.sa_handler
= sigchld_handler
;
5010 sigemptyset (&sigchld_action
.sa_mask
);
5011 sigchld_action
.sa_flags
= SA_RESTART
;
5013 /* Make it the default. */
5014 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
5016 /* Make sure we don't block SIGCHLD during a sigsuspend. */
5017 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
5018 sigdelset (&suspend_mask
, SIGCHLD
);
5020 sigemptyset (&blocked_mask
);
5024 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
5025 the GNU/Linux Threads library and therefore doesn't really belong
5028 /* Read variable NAME in the target and return its value if found.
5029 Otherwise return zero. It is assumed that the type of the variable
5033 get_signo (const char *name
)
5035 struct bound_minimal_symbol ms
;
5038 ms
= lookup_minimal_symbol (name
, NULL
, NULL
);
5039 if (ms
.minsym
== NULL
)
5042 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms
), (gdb_byte
*) &signo
,
5043 sizeof (signo
)) != 0)
5049 /* Return the set of signals used by the threads library in *SET. */
5052 lin_thread_get_thread_signals (sigset_t
*set
)
5054 struct sigaction action
;
5055 int restart
, cancel
;
5057 sigemptyset (&blocked_mask
);
5060 restart
= get_signo ("__pthread_sig_restart");
5061 cancel
= get_signo ("__pthread_sig_cancel");
5063 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5064 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5065 not provide any way for the debugger to query the signal numbers -
5066 fortunately they don't change! */
5069 restart
= __SIGRTMIN
;
5072 cancel
= __SIGRTMIN
+ 1;
5074 sigaddset (set
, restart
);
5075 sigaddset (set
, cancel
);
5077 /* The GNU/Linux Threads library makes terminating threads send a
5078 special "cancel" signal instead of SIGCHLD. Make sure we catch
5079 those (to prevent them from terminating GDB itself, which is
5080 likely to be their default action) and treat them the same way as
5083 action
.sa_handler
= sigchld_handler
;
5084 sigemptyset (&action
.sa_mask
);
5085 action
.sa_flags
= SA_RESTART
;
5086 sigaction (cancel
, &action
, NULL
);
5088 /* We block the "cancel" signal throughout this code ... */
5089 sigaddset (&blocked_mask
, cancel
);
5090 sigprocmask (SIG_BLOCK
, &blocked_mask
, NULL
);
5092 /* ... except during a sigsuspend. */
5093 sigdelset (&suspend_mask
, cancel
);