1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2013 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"
25 #include "gdb_string.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 "gdbthread.h" /* for struct thread_info etc. */
50 #include "gdb_stat.h" /* for struct stat */
51 #include <fcntl.h> /* for O_RDONLY */
53 #include "event-loop.h"
54 #include "event-top.h"
56 #include <sys/types.h>
57 #include "gdb_dirent.h"
58 #include "xml-support.h"
62 #include "linux-osdata.h"
63 #include "linux-tdep.h"
66 #include "tracepoint.h"
67 #include "exceptions.h"
68 #include "linux-ptrace.h"
70 #include "target-descriptions.h"
71 #include "filestuff.h"
74 #define SPUFS_MAGIC 0x23c9b64e
77 #ifdef HAVE_PERSONALITY
78 # include <sys/personality.h>
79 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
80 # define ADDR_NO_RANDOMIZE 0x0040000
82 #endif /* HAVE_PERSONALITY */
84 /* This comment documents high-level logic of this file.
86 Waiting for events in sync mode
87 ===============================
89 When waiting for an event in a specific thread, we just use waitpid, passing
90 the specific pid, and not passing WNOHANG.
92 When waiting for an event in all threads, waitpid is not quite good. Prior to
93 version 2.4, Linux can either wait for event in main thread, or in secondary
94 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
95 miss an event. The solution is to use non-blocking waitpid, together with
96 sigsuspend. First, we use non-blocking waitpid to get an event in the main
97 process, if any. Second, we use non-blocking waitpid with the __WCLONED
98 flag to check for events in cloned processes. If nothing is found, we use
99 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
100 happened to a child process -- and SIGCHLD will be delivered both for events
101 in main debugged process and in cloned processes. As soon as we know there's
102 an event, we get back to calling nonblocking waitpid with and without
105 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
106 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
107 blocked, the signal becomes pending and sigsuspend immediately
108 notices it and returns.
110 Waiting for events in async mode
111 ================================
113 In async mode, GDB should always be ready to handle both user input
114 and target events, so neither blocking waitpid nor sigsuspend are
115 viable options. Instead, we should asynchronously notify the GDB main
116 event loop whenever there's an unprocessed event from the target. We
117 detect asynchronous target events by handling SIGCHLD signals. To
118 notify the event loop about target events, the self-pipe trick is used
119 --- a pipe is registered as waitable event source in the event loop,
120 the event loop select/poll's on the read end of this pipe (as well on
121 other event sources, e.g., stdin), and the SIGCHLD handler writes a
122 byte to this pipe. This is more portable than relying on
123 pselect/ppoll, since on kernels that lack those syscalls, libc
124 emulates them with select/poll+sigprocmask, and that is racy
125 (a.k.a. plain broken).
127 Obviously, if we fail to notify the event loop if there's a target
128 event, it's bad. OTOH, if we notify the event loop when there's no
129 event from the target, linux_nat_wait will detect that there's no real
130 event to report, and return event of type TARGET_WAITKIND_IGNORE.
131 This is mostly harmless, but it will waste time and is better avoided.
133 The main design point is that every time GDB is outside linux-nat.c,
134 we have a SIGCHLD handler installed that is called when something
135 happens to the target and notifies the GDB event loop. Whenever GDB
136 core decides to handle the event, and calls into linux-nat.c, we
137 process things as in sync mode, except that the we never block in
140 While processing an event, we may end up momentarily blocked in
141 waitpid calls. Those waitpid calls, while blocking, are guarantied to
142 return quickly. E.g., in all-stop mode, before reporting to the core
143 that an LWP hit a breakpoint, all LWPs are stopped by sending them
144 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
145 Note that this is different from blocking indefinitely waiting for the
146 next event --- here, we're already handling an event.
151 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
152 signal is not entirely significant; we just need for a signal to be delivered,
153 so that we can intercept it. SIGSTOP's advantage is that it can not be
154 blocked. A disadvantage is that it is not a real-time signal, so it can only
155 be queued once; we do not keep track of other sources of SIGSTOP.
157 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
158 use them, because they have special behavior when the signal is generated -
159 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
160 kills the entire thread group.
162 A delivered SIGSTOP would stop the entire thread group, not just the thread we
163 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
164 cancel it (by PTRACE_CONT without passing SIGSTOP).
166 We could use a real-time signal instead. This would solve those problems; we
167 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
168 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
169 generates it, and there are races with trying to find a signal that is not
173 #define O_LARGEFILE 0
176 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
177 the use of the multi-threaded target. */
178 static struct target_ops
*linux_ops
;
179 static struct target_ops linux_ops_saved
;
181 /* The method to call, if any, when a new thread is attached. */
182 static void (*linux_nat_new_thread
) (struct lwp_info
*);
184 /* The method to call, if any, when a new fork is attached. */
185 static linux_nat_new_fork_ftype
*linux_nat_new_fork
;
187 /* The method to call, if any, when a process is no longer
189 static linux_nat_forget_process_ftype
*linux_nat_forget_process_hook
;
191 /* Hook to call prior to resuming a thread. */
192 static void (*linux_nat_prepare_to_resume
) (struct lwp_info
*);
194 /* The method to call, if any, when the siginfo object needs to be
195 converted between the layout returned by ptrace, and the layout in
196 the architecture of the inferior. */
197 static int (*linux_nat_siginfo_fixup
) (siginfo_t
*,
201 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
202 Called by our to_xfer_partial. */
203 static LONGEST (*super_xfer_partial
) (struct target_ops
*,
205 const char *, gdb_byte
*,
209 static unsigned int debug_linux_nat
;
211 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
212 struct cmd_list_element
*c
, const char *value
)
214 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
218 struct simple_pid_list
222 struct simple_pid_list
*next
;
224 struct simple_pid_list
*stopped_pids
;
226 /* Async mode support. */
228 /* The read/write ends of the pipe registered as waitable file in the
230 static int linux_nat_event_pipe
[2] = { -1, -1 };
232 /* Flush the event pipe. */
235 async_file_flush (void)
242 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
244 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
247 /* Put something (anything, doesn't matter what, or how much) in event
248 pipe, so that the select/poll in the event-loop realizes we have
249 something to process. */
252 async_file_mark (void)
256 /* It doesn't really matter what the pipe contains, as long we end
257 up with something in it. Might as well flush the previous
263 ret
= write (linux_nat_event_pipe
[1], "+", 1);
265 while (ret
== -1 && errno
== EINTR
);
267 /* Ignore EAGAIN. If the pipe is full, the event loop will already
268 be awakened anyway. */
271 static void linux_nat_async (void (*callback
)
272 (enum inferior_event_type event_type
,
275 static int kill_lwp (int lwpid
, int signo
);
277 static int stop_callback (struct lwp_info
*lp
, void *data
);
279 static void block_child_signals (sigset_t
*prev_mask
);
280 static void restore_child_signals_mask (sigset_t
*prev_mask
);
283 static struct lwp_info
*add_lwp (ptid_t ptid
);
284 static void purge_lwp_list (int pid
);
285 static void delete_lwp (ptid_t ptid
);
286 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
289 /* Trivial list manipulation functions to keep track of a list of
290 new stopped processes. */
292 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
294 struct simple_pid_list
*new_pid
= xmalloc (sizeof (struct simple_pid_list
));
297 new_pid
->status
= status
;
298 new_pid
->next
= *listp
;
303 in_pid_list_p (struct simple_pid_list
*list
, int pid
)
305 struct simple_pid_list
*p
;
307 for (p
= list
; p
!= NULL
; p
= p
->next
)
314 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
316 struct simple_pid_list
**p
;
318 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
319 if ((*p
)->pid
== pid
)
321 struct simple_pid_list
*next
= (*p
)->next
;
323 *statusp
= (*p
)->status
;
331 /* Initialize ptrace warnings and check for supported ptrace
332 features given PID. */
335 linux_init_ptrace (pid_t pid
)
337 linux_enable_event_reporting (pid
);
338 linux_ptrace_init_warnings ();
342 linux_child_post_attach (int pid
)
344 linux_init_ptrace (pid
);
348 linux_child_post_startup_inferior (ptid_t ptid
)
350 linux_init_ptrace (ptid_get_pid (ptid
));
353 /* Return the number of known LWPs in the tgid given by PID. */
361 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
362 if (ptid_get_pid (lp
->ptid
) == pid
)
368 /* Call delete_lwp with prototype compatible for make_cleanup. */
371 delete_lwp_cleanup (void *lp_voidp
)
373 struct lwp_info
*lp
= lp_voidp
;
375 delete_lwp (lp
->ptid
);
379 linux_child_follow_fork (struct target_ops
*ops
, int follow_child
)
382 int parent_pid
, child_pid
;
384 has_vforked
= (inferior_thread ()->pending_follow
.kind
385 == TARGET_WAITKIND_VFORKED
);
386 parent_pid
= ptid_get_lwp (inferior_ptid
);
388 parent_pid
= ptid_get_pid (inferior_ptid
);
389 child_pid
= PIDGET (inferior_thread ()->pending_follow
.value
.related_pid
);
392 && !non_stop
/* Non-stop always resumes both branches. */
393 && (!target_is_async_p () || sync_execution
)
394 && !(follow_child
|| detach_fork
|| sched_multi
))
396 /* The parent stays blocked inside the vfork syscall until the
397 child execs or exits. If we don't let the child run, then
398 the parent stays blocked. If we're telling the parent to run
399 in the foreground, the user will not be able to ctrl-c to get
400 back the terminal, effectively hanging the debug session. */
401 fprintf_filtered (gdb_stderr
, _("\
402 Can not resume the parent process over vfork in the foreground while\n\
403 holding the child stopped. Try \"set detach-on-fork\" or \
404 \"set schedule-multiple\".\n"));
405 /* FIXME output string > 80 columns. */
411 struct lwp_info
*child_lp
= NULL
;
413 /* We're already attached to the parent, by default. */
415 /* Detach new forked process? */
418 struct cleanup
*old_chain
;
420 /* Before detaching from the child, remove all breakpoints
421 from it. If we forked, then this has already been taken
422 care of by infrun.c. If we vforked however, any
423 breakpoint inserted in the parent is visible in the
424 child, even those added while stopped in a vfork
425 catchpoint. This will remove the breakpoints from the
426 parent also, but they'll be reinserted below. */
429 /* keep breakpoints list in sync. */
430 remove_breakpoints_pid (GET_PID (inferior_ptid
));
433 if (info_verbose
|| debug_linux_nat
)
435 target_terminal_ours ();
436 fprintf_filtered (gdb_stdlog
,
437 "Detaching after fork from "
438 "child process %d.\n",
442 old_chain
= save_inferior_ptid ();
443 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
445 child_lp
= add_lwp (inferior_ptid
);
446 child_lp
->stopped
= 1;
447 child_lp
->last_resume_kind
= resume_stop
;
448 make_cleanup (delete_lwp_cleanup
, child_lp
);
450 if (linux_nat_prepare_to_resume
!= NULL
)
451 linux_nat_prepare_to_resume (child_lp
);
452 ptrace (PTRACE_DETACH
, child_pid
, 0, 0);
454 do_cleanups (old_chain
);
458 struct inferior
*parent_inf
, *child_inf
;
459 struct cleanup
*old_chain
;
461 /* Add process to GDB's tables. */
462 child_inf
= add_inferior (child_pid
);
464 parent_inf
= current_inferior ();
465 child_inf
->attach_flag
= parent_inf
->attach_flag
;
466 copy_terminal_info (child_inf
, parent_inf
);
467 child_inf
->gdbarch
= parent_inf
->gdbarch
;
468 copy_inferior_target_desc_info (child_inf
, parent_inf
);
470 old_chain
= save_inferior_ptid ();
471 save_current_program_space ();
473 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
474 add_thread (inferior_ptid
);
475 child_lp
= add_lwp (inferior_ptid
);
476 child_lp
->stopped
= 1;
477 child_lp
->last_resume_kind
= resume_stop
;
478 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
480 /* If this is a vfork child, then the address-space is
481 shared with the parent. */
484 child_inf
->pspace
= parent_inf
->pspace
;
485 child_inf
->aspace
= parent_inf
->aspace
;
487 /* The parent will be frozen until the child is done
488 with the shared region. Keep track of the
490 child_inf
->vfork_parent
= parent_inf
;
491 child_inf
->pending_detach
= 0;
492 parent_inf
->vfork_child
= child_inf
;
493 parent_inf
->pending_detach
= 0;
497 child_inf
->aspace
= new_address_space ();
498 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
499 child_inf
->removable
= 1;
500 set_current_program_space (child_inf
->pspace
);
501 clone_program_space (child_inf
->pspace
, parent_inf
->pspace
);
503 /* Let the shared library layer (solib-svr4) learn about
504 this new process, relocate the cloned exec, pull in
505 shared libraries, and install the solib event
506 breakpoint. If a "cloned-VM" event was propagated
507 better throughout the core, this wouldn't be
509 solib_create_inferior_hook (0);
512 /* Let the thread_db layer learn about this new process. */
513 check_for_thread_db ();
515 do_cleanups (old_chain
);
520 struct lwp_info
*parent_lp
;
521 struct inferior
*parent_inf
;
523 parent_inf
= current_inferior ();
525 /* If we detached from the child, then we have to be careful
526 to not insert breakpoints in the parent until the child
527 is done with the shared memory region. However, if we're
528 staying attached to the child, then we can and should
529 insert breakpoints, so that we can debug it. A
530 subsequent child exec or exit is enough to know when does
531 the child stops using the parent's address space. */
532 parent_inf
->waiting_for_vfork_done
= detach_fork
;
533 parent_inf
->pspace
->breakpoints_not_allowed
= detach_fork
;
535 parent_lp
= find_lwp_pid (pid_to_ptid (parent_pid
));
536 gdb_assert (linux_supports_tracefork () >= 0);
538 if (linux_supports_tracevforkdone ())
541 fprintf_unfiltered (gdb_stdlog
,
542 "LCFF: waiting for VFORK_DONE on %d\n",
544 parent_lp
->stopped
= 1;
546 /* We'll handle the VFORK_DONE event like any other
547 event, in target_wait. */
551 /* We can't insert breakpoints until the child has
552 finished with the shared memory region. We need to
553 wait until that happens. Ideal would be to just
555 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
556 - waitpid (parent_pid, &status, __WALL);
557 However, most architectures can't handle a syscall
558 being traced on the way out if it wasn't traced on
561 We might also think to loop, continuing the child
562 until it exits or gets a SIGTRAP. One problem is
563 that the child might call ptrace with PTRACE_TRACEME.
565 There's no simple and reliable way to figure out when
566 the vforked child will be done with its copy of the
567 shared memory. We could step it out of the syscall,
568 two instructions, let it go, and then single-step the
569 parent once. When we have hardware single-step, this
570 would work; with software single-step it could still
571 be made to work but we'd have to be able to insert
572 single-step breakpoints in the child, and we'd have
573 to insert -just- the single-step breakpoint in the
574 parent. Very awkward.
576 In the end, the best we can do is to make sure it
577 runs for a little while. Hopefully it will be out of
578 range of any breakpoints we reinsert. Usually this
579 is only the single-step breakpoint at vfork's return
583 fprintf_unfiltered (gdb_stdlog
,
584 "LCFF: no VFORK_DONE "
585 "support, sleeping a bit\n");
589 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
590 and leave it pending. The next linux_nat_resume call
591 will notice a pending event, and bypasses actually
592 resuming the inferior. */
593 parent_lp
->status
= 0;
594 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
595 parent_lp
->stopped
= 1;
597 /* If we're in async mode, need to tell the event loop
598 there's something here to process. */
599 if (target_can_async_p ())
606 struct inferior
*parent_inf
, *child_inf
;
607 struct lwp_info
*child_lp
;
608 struct program_space
*parent_pspace
;
610 if (info_verbose
|| debug_linux_nat
)
612 target_terminal_ours ();
614 fprintf_filtered (gdb_stdlog
,
615 _("Attaching after process %d "
616 "vfork to child process %d.\n"),
617 parent_pid
, child_pid
);
619 fprintf_filtered (gdb_stdlog
,
620 _("Attaching after process %d "
621 "fork to child process %d.\n"),
622 parent_pid
, child_pid
);
625 /* Add the new inferior first, so that the target_detach below
626 doesn't unpush the target. */
628 child_inf
= add_inferior (child_pid
);
630 parent_inf
= current_inferior ();
631 child_inf
->attach_flag
= parent_inf
->attach_flag
;
632 copy_terminal_info (child_inf
, parent_inf
);
633 child_inf
->gdbarch
= parent_inf
->gdbarch
;
634 copy_inferior_target_desc_info (child_inf
, parent_inf
);
636 parent_pspace
= parent_inf
->pspace
;
638 /* If we're vforking, we want to hold on to the parent until the
639 child exits or execs. At child exec or exit time we can
640 remove the old breakpoints from the parent and detach or
641 resume debugging it. Otherwise, detach the parent now; we'll
642 want to reuse it's program/address spaces, but we can't set
643 them to the child before removing breakpoints from the
644 parent, otherwise, the breakpoints module could decide to
645 remove breakpoints from the wrong process (since they'd be
646 assigned to the same address space). */
650 gdb_assert (child_inf
->vfork_parent
== NULL
);
651 gdb_assert (parent_inf
->vfork_child
== NULL
);
652 child_inf
->vfork_parent
= parent_inf
;
653 child_inf
->pending_detach
= 0;
654 parent_inf
->vfork_child
= child_inf
;
655 parent_inf
->pending_detach
= detach_fork
;
656 parent_inf
->waiting_for_vfork_done
= 0;
658 else if (detach_fork
)
659 target_detach (NULL
, 0);
661 /* Note that the detach above makes PARENT_INF dangling. */
663 /* Add the child thread to the appropriate lists, and switch to
664 this new thread, before cloning the program space, and
665 informing the solib layer about this new process. */
667 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
668 add_thread (inferior_ptid
);
669 child_lp
= add_lwp (inferior_ptid
);
670 child_lp
->stopped
= 1;
671 child_lp
->last_resume_kind
= resume_stop
;
673 /* If this is a vfork child, then the address-space is shared
674 with the parent. If we detached from the parent, then we can
675 reuse the parent's program/address spaces. */
676 if (has_vforked
|| detach_fork
)
678 child_inf
->pspace
= parent_pspace
;
679 child_inf
->aspace
= child_inf
->pspace
->aspace
;
683 child_inf
->aspace
= new_address_space ();
684 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
685 child_inf
->removable
= 1;
686 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
687 set_current_program_space (child_inf
->pspace
);
688 clone_program_space (child_inf
->pspace
, parent_pspace
);
690 /* Let the shared library layer (solib-svr4) learn about
691 this new process, relocate the cloned exec, pull in
692 shared libraries, and install the solib event breakpoint.
693 If a "cloned-VM" event was propagated better throughout
694 the core, this wouldn't be required. */
695 solib_create_inferior_hook (0);
698 /* Let the thread_db layer learn about this new process. */
699 check_for_thread_db ();
707 linux_child_insert_fork_catchpoint (int pid
)
709 return !linux_supports_tracefork ();
713 linux_child_remove_fork_catchpoint (int pid
)
719 linux_child_insert_vfork_catchpoint (int pid
)
721 return !linux_supports_tracefork ();
725 linux_child_remove_vfork_catchpoint (int pid
)
731 linux_child_insert_exec_catchpoint (int pid
)
733 return !linux_supports_tracefork ();
737 linux_child_remove_exec_catchpoint (int pid
)
743 linux_child_set_syscall_catchpoint (int pid
, int needed
, int any_count
,
744 int table_size
, int *table
)
746 if (!linux_supports_tracesysgood ())
749 /* On GNU/Linux, we ignore the arguments. It means that we only
750 enable the syscall catchpoints, but do not disable them.
752 Also, we do not use the `table' information because we do not
753 filter system calls here. We let GDB do the logic for us. */
757 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
758 are processes sharing the same VM space. A multi-threaded process
759 is basically a group of such processes. However, such a grouping
760 is almost entirely a user-space issue; the kernel doesn't enforce
761 such a grouping at all (this might change in the future). In
762 general, we'll rely on the threads library (i.e. the GNU/Linux
763 Threads library) to provide such a grouping.
765 It is perfectly well possible to write a multi-threaded application
766 without the assistance of a threads library, by using the clone
767 system call directly. This module should be able to give some
768 rudimentary support for debugging such applications if developers
769 specify the CLONE_PTRACE flag in the clone system call, and are
770 using the Linux kernel 2.4 or above.
772 Note that there are some peculiarities in GNU/Linux that affect
775 - In general one should specify the __WCLONE flag to waitpid in
776 order to make it report events for any of the cloned processes
777 (and leave it out for the initial process). However, if a cloned
778 process has exited the exit status is only reported if the
779 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
780 we cannot use it since GDB must work on older systems too.
782 - When a traced, cloned process exits and is waited for by the
783 debugger, the kernel reassigns it to the original parent and
784 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
785 library doesn't notice this, which leads to the "zombie problem":
786 When debugged a multi-threaded process that spawns a lot of
787 threads will run out of processes, even if the threads exit,
788 because the "zombies" stay around. */
790 /* List of known LWPs. */
791 struct lwp_info
*lwp_list
;
794 /* Original signal mask. */
795 static sigset_t normal_mask
;
797 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
798 _initialize_linux_nat. */
799 static sigset_t suspend_mask
;
801 /* Signals to block to make that sigsuspend work. */
802 static sigset_t blocked_mask
;
804 /* SIGCHLD action. */
805 struct sigaction sigchld_action
;
807 /* Block child signals (SIGCHLD and linux threads signals), and store
808 the previous mask in PREV_MASK. */
811 block_child_signals (sigset_t
*prev_mask
)
813 /* Make sure SIGCHLD is blocked. */
814 if (!sigismember (&blocked_mask
, SIGCHLD
))
815 sigaddset (&blocked_mask
, SIGCHLD
);
817 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
820 /* Restore child signals mask, previously returned by
821 block_child_signals. */
824 restore_child_signals_mask (sigset_t
*prev_mask
)
826 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
829 /* Mask of signals to pass directly to the inferior. */
830 static sigset_t pass_mask
;
832 /* Update signals to pass to the inferior. */
834 linux_nat_pass_signals (int numsigs
, unsigned char *pass_signals
)
838 sigemptyset (&pass_mask
);
840 for (signo
= 1; signo
< NSIG
; signo
++)
842 int target_signo
= gdb_signal_from_host (signo
);
843 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
844 sigaddset (&pass_mask
, signo
);
850 /* Prototypes for local functions. */
851 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
852 static int linux_thread_alive (ptid_t ptid
);
853 static char *linux_child_pid_to_exec_file (int pid
);
856 /* Convert wait status STATUS to a string. Used for printing debug
860 status_to_str (int status
)
864 if (WIFSTOPPED (status
))
866 if (WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
867 snprintf (buf
, sizeof (buf
), "%s (stopped at syscall)",
868 strsignal (SIGTRAP
));
870 snprintf (buf
, sizeof (buf
), "%s (stopped)",
871 strsignal (WSTOPSIG (status
)));
873 else if (WIFSIGNALED (status
))
874 snprintf (buf
, sizeof (buf
), "%s (terminated)",
875 strsignal (WTERMSIG (status
)));
877 snprintf (buf
, sizeof (buf
), "%d (exited)", WEXITSTATUS (status
));
882 /* Destroy and free LP. */
885 lwp_free (struct lwp_info
*lp
)
887 xfree (lp
->arch_private
);
891 /* Remove all LWPs belong to PID from the lwp list. */
894 purge_lwp_list (int pid
)
896 struct lwp_info
*lp
, *lpprev
, *lpnext
;
900 for (lp
= lwp_list
; lp
; lp
= lpnext
)
904 if (ptid_get_pid (lp
->ptid
) == pid
)
909 lpprev
->next
= lp
->next
;
918 /* Add the LWP specified by PTID to the list. PTID is the first LWP
919 in the process. Return a pointer to the structure describing the
922 This differs from add_lwp in that we don't let the arch specific
923 bits know about this new thread. Current clients of this callback
924 take the opportunity to install watchpoints in the new thread, and
925 we shouldn't do that for the first thread. If we're spawning a
926 child ("run"), the thread executes the shell wrapper first, and we
927 shouldn't touch it until it execs the program we want to debug.
928 For "attach", it'd be okay to call the callback, but it's not
929 necessary, because watchpoints can't yet have been inserted into
932 static struct lwp_info
*
933 add_initial_lwp (ptid_t ptid
)
937 gdb_assert (is_lwp (ptid
));
939 lp
= (struct lwp_info
*) xmalloc (sizeof (struct lwp_info
));
941 memset (lp
, 0, sizeof (struct lwp_info
));
943 lp
->last_resume_kind
= resume_continue
;
944 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
955 /* Add the LWP specified by PID to the list. Return a pointer to the
956 structure describing the new LWP. The LWP should already be
959 static struct lwp_info
*
960 add_lwp (ptid_t ptid
)
964 lp
= add_initial_lwp (ptid
);
966 /* Let the arch specific bits know about this new thread. Current
967 clients of this callback take the opportunity to install
968 watchpoints in the new thread. We don't do this for the first
969 thread though. See add_initial_lwp. */
970 if (linux_nat_new_thread
!= NULL
)
971 linux_nat_new_thread (lp
);
976 /* Remove the LWP specified by PID from the list. */
979 delete_lwp (ptid_t ptid
)
981 struct lwp_info
*lp
, *lpprev
;
985 for (lp
= lwp_list
; lp
; lpprev
= lp
, lp
= lp
->next
)
986 if (ptid_equal (lp
->ptid
, ptid
))
993 lpprev
->next
= lp
->next
;
1000 /* Return a pointer to the structure describing the LWP corresponding
1001 to PID. If no corresponding LWP could be found, return NULL. */
1003 static struct lwp_info
*
1004 find_lwp_pid (ptid_t ptid
)
1006 struct lwp_info
*lp
;
1010 lwp
= GET_LWP (ptid
);
1012 lwp
= GET_PID (ptid
);
1014 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
1015 if (lwp
== GET_LWP (lp
->ptid
))
1021 /* Call CALLBACK with its second argument set to DATA for every LWP in
1022 the list. If CALLBACK returns 1 for a particular LWP, return a
1023 pointer to the structure describing that LWP immediately.
1024 Otherwise return NULL. */
1027 iterate_over_lwps (ptid_t filter
,
1028 int (*callback
) (struct lwp_info
*, void *),
1031 struct lwp_info
*lp
, *lpnext
;
1033 for (lp
= lwp_list
; lp
; lp
= lpnext
)
1037 if (ptid_match (lp
->ptid
, filter
))
1039 if ((*callback
) (lp
, data
))
1047 /* Update our internal state when changing from one checkpoint to
1048 another indicated by NEW_PTID. We can only switch single-threaded
1049 applications, so we only create one new LWP, and the previous list
1053 linux_nat_switch_fork (ptid_t new_ptid
)
1055 struct lwp_info
*lp
;
1057 purge_lwp_list (GET_PID (inferior_ptid
));
1059 lp
= add_lwp (new_ptid
);
1062 /* This changes the thread's ptid while preserving the gdb thread
1063 num. Also changes the inferior pid, while preserving the
1065 thread_change_ptid (inferior_ptid
, new_ptid
);
1067 /* We've just told GDB core that the thread changed target id, but,
1068 in fact, it really is a different thread, with different register
1070 registers_changed ();
1073 /* Handle the exit of a single thread LP. */
1076 exit_lwp (struct lwp_info
*lp
)
1078 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1082 if (print_thread_events
)
1083 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
1085 delete_thread (lp
->ptid
);
1088 delete_lwp (lp
->ptid
);
1091 /* Wait for the LWP specified by LP, which we have just attached to.
1092 Returns a wait status for that LWP, to cache. */
1095 linux_nat_post_attach_wait (ptid_t ptid
, int first
, int *cloned
,
1098 pid_t new_pid
, pid
= GET_LWP (ptid
);
1101 if (linux_proc_pid_is_stopped (pid
))
1103 if (debug_linux_nat
)
1104 fprintf_unfiltered (gdb_stdlog
,
1105 "LNPAW: Attaching to a stopped process\n");
1107 /* The process is definitely stopped. It is in a job control
1108 stop, unless the kernel predates the TASK_STOPPED /
1109 TASK_TRACED distinction, in which case it might be in a
1110 ptrace stop. Make sure it is in a ptrace stop; from there we
1111 can kill it, signal it, et cetera.
1113 First make sure there is a pending SIGSTOP. Since we are
1114 already attached, the process can not transition from stopped
1115 to running without a PTRACE_CONT; so we know this signal will
1116 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1117 probably already in the queue (unless this kernel is old
1118 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1119 is not an RT signal, it can only be queued once. */
1120 kill_lwp (pid
, SIGSTOP
);
1122 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1123 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1124 ptrace (PTRACE_CONT
, pid
, 0, 0);
1127 /* Make sure the initial process is stopped. The user-level threads
1128 layer might want to poke around in the inferior, and that won't
1129 work if things haven't stabilized yet. */
1130 new_pid
= my_waitpid (pid
, &status
, 0);
1131 if (new_pid
== -1 && errno
== ECHILD
)
1134 warning (_("%s is a cloned process"), target_pid_to_str (ptid
));
1136 /* Try again with __WCLONE to check cloned processes. */
1137 new_pid
= my_waitpid (pid
, &status
, __WCLONE
);
1141 gdb_assert (pid
== new_pid
);
1143 if (!WIFSTOPPED (status
))
1145 /* The pid we tried to attach has apparently just exited. */
1146 if (debug_linux_nat
)
1147 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1148 pid
, status_to_str (status
));
1152 if (WSTOPSIG (status
) != SIGSTOP
)
1155 if (debug_linux_nat
)
1156 fprintf_unfiltered (gdb_stdlog
,
1157 "LNPAW: Received %s after attaching\n",
1158 status_to_str (status
));
1164 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1165 the new LWP could not be attached, or 1 if we're already auto
1166 attached to this thread, but haven't processed the
1167 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1168 its existance, without considering it an error. */
1171 lin_lwp_attach_lwp (ptid_t ptid
)
1173 struct lwp_info
*lp
;
1176 gdb_assert (is_lwp (ptid
));
1178 lp
= find_lwp_pid (ptid
);
1179 lwpid
= GET_LWP (ptid
);
1181 /* We assume that we're already attached to any LWP that has an id
1182 equal to the overall process id, and to any LWP that is already
1183 in our list of LWPs. If we're not seeing exit events from threads
1184 and we've had PID wraparound since we last tried to stop all threads,
1185 this assumption might be wrong; fortunately, this is very unlikely
1187 if (lwpid
!= GET_PID (ptid
) && lp
== NULL
)
1189 int status
, cloned
= 0, signalled
= 0;
1191 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1193 if (linux_supports_tracefork ())
1195 /* If we haven't stopped all threads when we get here,
1196 we may have seen a thread listed in thread_db's list,
1197 but not processed the PTRACE_EVENT_CLONE yet. If
1198 that's the case, ignore this new thread, and let
1199 normal event handling discover it later. */
1200 if (in_pid_list_p (stopped_pids
, lwpid
))
1202 /* We've already seen this thread stop, but we
1203 haven't seen the PTRACE_EVENT_CLONE extended
1212 /* See if we've got a stop for this new child
1213 pending. If so, we're already attached. */
1214 new_pid
= my_waitpid (lwpid
, &status
, WNOHANG
);
1215 if (new_pid
== -1 && errno
== ECHILD
)
1216 new_pid
= my_waitpid (lwpid
, &status
, __WCLONE
| WNOHANG
);
1219 if (WIFSTOPPED (status
))
1220 add_to_pid_list (&stopped_pids
, lwpid
, status
);
1226 /* If we fail to attach to the thread, issue a warning,
1227 but continue. One way this can happen is if thread
1228 creation is interrupted; as of Linux kernel 2.6.19, a
1229 bug may place threads in the thread list and then fail
1231 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid
),
1232 safe_strerror (errno
));
1236 if (debug_linux_nat
)
1237 fprintf_unfiltered (gdb_stdlog
,
1238 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1239 target_pid_to_str (ptid
));
1241 status
= linux_nat_post_attach_wait (ptid
, 0, &cloned
, &signalled
);
1242 if (!WIFSTOPPED (status
))
1245 lp
= add_lwp (ptid
);
1247 lp
->cloned
= cloned
;
1248 lp
->signalled
= signalled
;
1249 if (WSTOPSIG (status
) != SIGSTOP
)
1252 lp
->status
= status
;
1255 target_post_attach (GET_LWP (lp
->ptid
));
1257 if (debug_linux_nat
)
1259 fprintf_unfiltered (gdb_stdlog
,
1260 "LLAL: waitpid %s received %s\n",
1261 target_pid_to_str (ptid
),
1262 status_to_str (status
));
1267 /* We assume that the LWP representing the original process is
1268 already stopped. Mark it as stopped in the data structure
1269 that the GNU/linux ptrace layer uses to keep track of
1270 threads. Note that this won't have already been done since
1271 the main thread will have, we assume, been stopped by an
1272 attach from a different layer. */
1274 lp
= add_lwp (ptid
);
1278 lp
->last_resume_kind
= resume_stop
;
1283 linux_nat_create_inferior (struct target_ops
*ops
,
1284 char *exec_file
, char *allargs
, char **env
,
1287 #ifdef HAVE_PERSONALITY
1288 int personality_orig
= 0, personality_set
= 0;
1289 #endif /* HAVE_PERSONALITY */
1291 /* The fork_child mechanism is synchronous and calls target_wait, so
1292 we have to mask the async mode. */
1294 #ifdef HAVE_PERSONALITY
1295 if (disable_randomization
)
1298 personality_orig
= personality (0xffffffff);
1299 if (errno
== 0 && !(personality_orig
& ADDR_NO_RANDOMIZE
))
1301 personality_set
= 1;
1302 personality (personality_orig
| ADDR_NO_RANDOMIZE
);
1304 if (errno
!= 0 || (personality_set
1305 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE
)))
1306 warning (_("Error disabling address space randomization: %s"),
1307 safe_strerror (errno
));
1309 #endif /* HAVE_PERSONALITY */
1311 /* Make sure we report all signals during startup. */
1312 linux_nat_pass_signals (0, NULL
);
1314 linux_ops
->to_create_inferior (ops
, exec_file
, allargs
, env
, from_tty
);
1316 #ifdef HAVE_PERSONALITY
1317 if (personality_set
)
1320 personality (personality_orig
);
1322 warning (_("Error restoring address space randomization: %s"),
1323 safe_strerror (errno
));
1325 #endif /* HAVE_PERSONALITY */
1329 linux_nat_attach (struct target_ops
*ops
, char *args
, int from_tty
)
1331 struct lwp_info
*lp
;
1334 volatile struct gdb_exception ex
;
1336 /* Make sure we report all signals during attach. */
1337 linux_nat_pass_signals (0, NULL
);
1339 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
1341 linux_ops
->to_attach (ops
, args
, from_tty
);
1345 pid_t pid
= parse_pid_to_attach (args
);
1346 struct buffer buffer
;
1347 char *message
, *buffer_s
;
1349 message
= xstrdup (ex
.message
);
1350 make_cleanup (xfree
, message
);
1352 buffer_init (&buffer
);
1353 linux_ptrace_attach_warnings (pid
, &buffer
);
1355 buffer_grow_str0 (&buffer
, "");
1356 buffer_s
= buffer_finish (&buffer
);
1357 make_cleanup (xfree
, buffer_s
);
1359 throw_error (ex
.error
, "%s%s", buffer_s
, message
);
1362 /* The ptrace base target adds the main thread with (pid,0,0)
1363 format. Decorate it with lwp info. */
1364 ptid
= BUILD_LWP (GET_PID (inferior_ptid
), GET_PID (inferior_ptid
));
1365 thread_change_ptid (inferior_ptid
, ptid
);
1367 /* Add the initial process as the first LWP to the list. */
1368 lp
= add_initial_lwp (ptid
);
1370 status
= linux_nat_post_attach_wait (lp
->ptid
, 1, &lp
->cloned
,
1372 if (!WIFSTOPPED (status
))
1374 if (WIFEXITED (status
))
1376 int exit_code
= WEXITSTATUS (status
);
1378 target_terminal_ours ();
1379 target_mourn_inferior ();
1381 error (_("Unable to attach: program exited normally."));
1383 error (_("Unable to attach: program exited with code %d."),
1386 else if (WIFSIGNALED (status
))
1388 enum gdb_signal signo
;
1390 target_terminal_ours ();
1391 target_mourn_inferior ();
1393 signo
= gdb_signal_from_host (WTERMSIG (status
));
1394 error (_("Unable to attach: program terminated with signal "
1396 gdb_signal_to_name (signo
),
1397 gdb_signal_to_string (signo
));
1400 internal_error (__FILE__
, __LINE__
,
1401 _("unexpected status %d for PID %ld"),
1402 status
, (long) GET_LWP (ptid
));
1407 /* Save the wait status to report later. */
1409 if (debug_linux_nat
)
1410 fprintf_unfiltered (gdb_stdlog
,
1411 "LNA: waitpid %ld, saving status %s\n",
1412 (long) GET_PID (lp
->ptid
), status_to_str (status
));
1414 lp
->status
= status
;
1416 if (target_can_async_p ())
1417 target_async (inferior_event_handler
, 0);
1420 /* Get pending status of LP. */
1422 get_pending_status (struct lwp_info
*lp
, int *status
)
1424 enum gdb_signal signo
= GDB_SIGNAL_0
;
1426 /* If we paused threads momentarily, we may have stored pending
1427 events in lp->status or lp->waitstatus (see stop_wait_callback),
1428 and GDB core hasn't seen any signal for those threads.
1429 Otherwise, the last signal reported to the core is found in the
1430 thread object's stop_signal.
1432 There's a corner case that isn't handled here at present. Only
1433 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1434 stop_signal make sense as a real signal to pass to the inferior.
1435 Some catchpoint related events, like
1436 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1437 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1438 those traps are debug API (ptrace in our case) related and
1439 induced; the inferior wouldn't see them if it wasn't being
1440 traced. Hence, we should never pass them to the inferior, even
1441 when set to pass state. Since this corner case isn't handled by
1442 infrun.c when proceeding with a signal, for consistency, neither
1443 do we handle it here (or elsewhere in the file we check for
1444 signal pass state). Normally SIGTRAP isn't set to pass state, so
1445 this is really a corner case. */
1447 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1448 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1449 else if (lp
->status
)
1450 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1451 else if (non_stop
&& !is_executing (lp
->ptid
))
1453 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1455 signo
= tp
->suspend
.stop_signal
;
1459 struct target_waitstatus last
;
1462 get_last_target_status (&last_ptid
, &last
);
1464 if (GET_LWP (lp
->ptid
) == GET_LWP (last_ptid
))
1466 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1468 signo
= tp
->suspend
.stop_signal
;
1474 if (signo
== GDB_SIGNAL_0
)
1476 if (debug_linux_nat
)
1477 fprintf_unfiltered (gdb_stdlog
,
1478 "GPT: lwp %s has no pending signal\n",
1479 target_pid_to_str (lp
->ptid
));
1481 else if (!signal_pass_state (signo
))
1483 if (debug_linux_nat
)
1484 fprintf_unfiltered (gdb_stdlog
,
1485 "GPT: lwp %s had signal %s, "
1486 "but it is in no pass state\n",
1487 target_pid_to_str (lp
->ptid
),
1488 gdb_signal_to_string (signo
));
1492 *status
= W_STOPCODE (gdb_signal_to_host (signo
));
1494 if (debug_linux_nat
)
1495 fprintf_unfiltered (gdb_stdlog
,
1496 "GPT: lwp %s has pending signal %s\n",
1497 target_pid_to_str (lp
->ptid
),
1498 gdb_signal_to_string (signo
));
1505 detach_callback (struct lwp_info
*lp
, void *data
)
1507 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1509 if (debug_linux_nat
&& lp
->status
)
1510 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1511 strsignal (WSTOPSIG (lp
->status
)),
1512 target_pid_to_str (lp
->ptid
));
1514 /* If there is a pending SIGSTOP, get rid of it. */
1517 if (debug_linux_nat
)
1518 fprintf_unfiltered (gdb_stdlog
,
1519 "DC: Sending SIGCONT to %s\n",
1520 target_pid_to_str (lp
->ptid
));
1522 kill_lwp (GET_LWP (lp
->ptid
), SIGCONT
);
1526 /* We don't actually detach from the LWP that has an id equal to the
1527 overall process id just yet. */
1528 if (GET_LWP (lp
->ptid
) != GET_PID (lp
->ptid
))
1532 /* Pass on any pending signal for this LWP. */
1533 get_pending_status (lp
, &status
);
1535 if (linux_nat_prepare_to_resume
!= NULL
)
1536 linux_nat_prepare_to_resume (lp
);
1538 if (ptrace (PTRACE_DETACH
, GET_LWP (lp
->ptid
), 0,
1539 WSTOPSIG (status
)) < 0)
1540 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1541 safe_strerror (errno
));
1543 if (debug_linux_nat
)
1544 fprintf_unfiltered (gdb_stdlog
,
1545 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1546 target_pid_to_str (lp
->ptid
),
1547 strsignal (WSTOPSIG (status
)));
1549 delete_lwp (lp
->ptid
);
1556 linux_nat_detach (struct target_ops
*ops
, char *args
, int from_tty
)
1560 struct lwp_info
*main_lwp
;
1562 pid
= GET_PID (inferior_ptid
);
1564 /* Don't unregister from the event loop, as there may be other
1565 inferiors running. */
1567 /* Stop all threads before detaching. ptrace requires that the
1568 thread is stopped to sucessfully detach. */
1569 iterate_over_lwps (pid_to_ptid (pid
), stop_callback
, NULL
);
1570 /* ... and wait until all of them have reported back that
1571 they're no longer running. */
1572 iterate_over_lwps (pid_to_ptid (pid
), stop_wait_callback
, NULL
);
1574 iterate_over_lwps (pid_to_ptid (pid
), detach_callback
, NULL
);
1576 /* Only the initial process should be left right now. */
1577 gdb_assert (num_lwps (GET_PID (inferior_ptid
)) == 1);
1579 main_lwp
= find_lwp_pid (pid_to_ptid (pid
));
1581 /* Pass on any pending signal for the last LWP. */
1582 if ((args
== NULL
|| *args
== '\0')
1583 && get_pending_status (main_lwp
, &status
) != -1
1584 && WIFSTOPPED (status
))
1586 /* Put the signal number in ARGS so that inf_ptrace_detach will
1587 pass it along with PTRACE_DETACH. */
1589 sprintf (args
, "%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 (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 (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 (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 GET_LWP (lp
->ptid
));
1887 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1888 ptrace (PTRACE_CONT
, 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 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 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 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 (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
= 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 (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 (BUILD_LWP (new_pid
, GET_PID (lp
->ptid
)));
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 (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) 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 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
, pid_to_ptid (GET_LWP (lp
->ptid
)),
2187 if (event
== PTRACE_EVENT_EXEC
)
2189 if (debug_linux_nat
)
2190 fprintf_unfiltered (gdb_stdlog
,
2191 "LHEW: Got exec event from LWP %ld\n",
2192 GET_LWP (lp
->ptid
));
2194 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2195 ourstatus
->value
.execd_pathname
2196 = xstrdup (linux_child_pid_to_exec_file (pid
));
2201 if (event
== PTRACE_EVENT_VFORK_DONE
)
2203 if (current_inferior ()->waiting_for_vfork_done
)
2205 if (debug_linux_nat
)
2206 fprintf_unfiltered (gdb_stdlog
,
2207 "LHEW: Got expected PTRACE_EVENT_"
2208 "VFORK_DONE from LWP %ld: stopping\n",
2209 GET_LWP (lp
->ptid
));
2211 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2215 if (debug_linux_nat
)
2216 fprintf_unfiltered (gdb_stdlog
,
2217 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2218 "from LWP %ld: resuming\n",
2219 GET_LWP (lp
->ptid
));
2220 ptrace (PTRACE_CONT
, GET_LWP (lp
->ptid
), 0, 0);
2224 internal_error (__FILE__
, __LINE__
,
2225 _("unknown ptrace event %d"), event
);
2228 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2232 wait_lwp (struct lwp_info
*lp
)
2236 int thread_dead
= 0;
2239 gdb_assert (!lp
->stopped
);
2240 gdb_assert (lp
->status
== 0);
2242 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2243 block_child_signals (&prev_mask
);
2247 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2248 was right and we should just call sigsuspend. */
2250 pid
= my_waitpid (GET_LWP (lp
->ptid
), &status
, WNOHANG
);
2251 if (pid
== -1 && errno
== ECHILD
)
2252 pid
= my_waitpid (GET_LWP (lp
->ptid
), &status
, __WCLONE
| WNOHANG
);
2253 if (pid
== -1 && errno
== ECHILD
)
2255 /* The thread has previously exited. We need to delete it
2256 now because, for some vendor 2.4 kernels with NPTL
2257 support backported, there won't be an exit event unless
2258 it is the main thread. 2.6 kernels will report an exit
2259 event for each thread that exits, as expected. */
2261 if (debug_linux_nat
)
2262 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2263 target_pid_to_str (lp
->ptid
));
2268 /* Bugs 10970, 12702.
2269 Thread group leader may have exited in which case we'll lock up in
2270 waitpid if there are other threads, even if they are all zombies too.
2271 Basically, we're not supposed to use waitpid this way.
2272 __WCLONE is not applicable for the leader so we can't use that.
2273 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2274 process; it gets ESRCH both for the zombie and for running processes.
2276 As a workaround, check if we're waiting for the thread group leader and
2277 if it's a zombie, and avoid calling waitpid if it is.
2279 This is racy, what if the tgl becomes a zombie right after we check?
2280 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2281 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2283 if (GET_PID (lp
->ptid
) == GET_LWP (lp
->ptid
)
2284 && linux_proc_pid_is_zombie (GET_LWP (lp
->ptid
)))
2287 if (debug_linux_nat
)
2288 fprintf_unfiltered (gdb_stdlog
,
2289 "WL: Thread group leader %s vanished.\n",
2290 target_pid_to_str (lp
->ptid
));
2294 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2295 get invoked despite our caller had them intentionally blocked by
2296 block_child_signals. This is sensitive only to the loop of
2297 linux_nat_wait_1 and there if we get called my_waitpid gets called
2298 again before it gets to sigsuspend so we can safely let the handlers
2299 get executed here. */
2301 sigsuspend (&suspend_mask
);
2304 restore_child_signals_mask (&prev_mask
);
2308 gdb_assert (pid
== GET_LWP (lp
->ptid
));
2310 if (debug_linux_nat
)
2312 fprintf_unfiltered (gdb_stdlog
,
2313 "WL: waitpid %s received %s\n",
2314 target_pid_to_str (lp
->ptid
),
2315 status_to_str (status
));
2318 /* Check if the thread has exited. */
2319 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2322 if (debug_linux_nat
)
2323 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2324 target_pid_to_str (lp
->ptid
));
2334 gdb_assert (WIFSTOPPED (status
));
2336 /* Handle GNU/Linux's syscall SIGTRAPs. */
2337 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2339 /* No longer need the sysgood bit. The ptrace event ends up
2340 recorded in lp->waitstatus if we care for it. We can carry
2341 on handling the event like a regular SIGTRAP from here
2343 status
= W_STOPCODE (SIGTRAP
);
2344 if (linux_handle_syscall_trap (lp
, 1))
2345 return wait_lwp (lp
);
2348 /* Handle GNU/Linux's extended waitstatus for trace events. */
2349 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2351 if (debug_linux_nat
)
2352 fprintf_unfiltered (gdb_stdlog
,
2353 "WL: Handling extended status 0x%06x\n",
2355 if (linux_handle_extended_wait (lp
, status
, 1))
2356 return wait_lwp (lp
);
2362 /* Send a SIGSTOP to LP. */
2365 stop_callback (struct lwp_info
*lp
, void *data
)
2367 if (!lp
->stopped
&& !lp
->signalled
)
2371 if (debug_linux_nat
)
2373 fprintf_unfiltered (gdb_stdlog
,
2374 "SC: kill %s **<SIGSTOP>**\n",
2375 target_pid_to_str (lp
->ptid
));
2378 ret
= kill_lwp (GET_LWP (lp
->ptid
), SIGSTOP
);
2379 if (debug_linux_nat
)
2381 fprintf_unfiltered (gdb_stdlog
,
2382 "SC: lwp kill %d %s\n",
2384 errno
? safe_strerror (errno
) : "ERRNO-OK");
2388 gdb_assert (lp
->status
== 0);
2394 /* Request a stop on LWP. */
2397 linux_stop_lwp (struct lwp_info
*lwp
)
2399 stop_callback (lwp
, NULL
);
2402 /* Return non-zero if LWP PID has a pending SIGINT. */
2405 linux_nat_has_pending_sigint (int pid
)
2407 sigset_t pending
, blocked
, ignored
;
2409 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2411 if (sigismember (&pending
, SIGINT
)
2412 && !sigismember (&ignored
, SIGINT
))
2418 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2421 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2423 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2424 flag to consume the next one. */
2425 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2426 && WSTOPSIG (lp
->status
) == SIGINT
)
2429 lp
->ignore_sigint
= 1;
2434 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2435 This function is called after we know the LWP has stopped; if the LWP
2436 stopped before the expected SIGINT was delivered, then it will never have
2437 arrived. Also, if the signal was delivered to a shared queue and consumed
2438 by a different thread, it will never be delivered to this LWP. */
2441 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2443 if (!lp
->ignore_sigint
)
2446 if (!linux_nat_has_pending_sigint (GET_LWP (lp
->ptid
)))
2448 if (debug_linux_nat
)
2449 fprintf_unfiltered (gdb_stdlog
,
2450 "MCIS: Clearing bogus flag for %s\n",
2451 target_pid_to_str (lp
->ptid
));
2452 lp
->ignore_sigint
= 0;
2456 /* Fetch the possible triggered data watchpoint info and store it in
2459 On some archs, like x86, that use debug registers to set
2460 watchpoints, it's possible that the way to know which watched
2461 address trapped, is to check the register that is used to select
2462 which address to watch. Problem is, between setting the watchpoint
2463 and reading back which data address trapped, the user may change
2464 the set of watchpoints, and, as a consequence, GDB changes the
2465 debug registers in the inferior. To avoid reading back a stale
2466 stopped-data-address when that happens, we cache in LP the fact
2467 that a watchpoint trapped, and the corresponding data address, as
2468 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2469 registers meanwhile, we have the cached data we can rely on. */
2472 save_sigtrap (struct lwp_info
*lp
)
2474 struct cleanup
*old_chain
;
2476 if (linux_ops
->to_stopped_by_watchpoint
== NULL
)
2478 lp
->stopped_by_watchpoint
= 0;
2482 old_chain
= save_inferior_ptid ();
2483 inferior_ptid
= lp
->ptid
;
2485 lp
->stopped_by_watchpoint
= linux_ops
->to_stopped_by_watchpoint ();
2487 if (lp
->stopped_by_watchpoint
)
2489 if (linux_ops
->to_stopped_data_address
!= NULL
)
2490 lp
->stopped_data_address_p
=
2491 linux_ops
->to_stopped_data_address (¤t_target
,
2492 &lp
->stopped_data_address
);
2494 lp
->stopped_data_address_p
= 0;
2497 do_cleanups (old_chain
);
2500 /* See save_sigtrap. */
2503 linux_nat_stopped_by_watchpoint (void)
2505 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2507 gdb_assert (lp
!= NULL
);
2509 return lp
->stopped_by_watchpoint
;
2513 linux_nat_stopped_data_address (struct target_ops
*ops
, CORE_ADDR
*addr_p
)
2515 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2517 gdb_assert (lp
!= NULL
);
2519 *addr_p
= lp
->stopped_data_address
;
2521 return lp
->stopped_data_address_p
;
2524 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2527 sigtrap_is_event (int status
)
2529 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2532 /* SIGTRAP-like events recognizer. */
2534 static int (*linux_nat_status_is_event
) (int status
) = sigtrap_is_event
;
2536 /* Check for SIGTRAP-like events in LP. */
2539 linux_nat_lp_status_is_event (struct lwp_info
*lp
)
2541 /* We check for lp->waitstatus in addition to lp->status, because we can
2542 have pending process exits recorded in lp->status
2543 and W_EXITCODE(0,0) == 0. We should probably have an additional
2544 lp->status_p flag. */
2546 return (lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
2547 && linux_nat_status_is_event (lp
->status
));
2550 /* Set alternative SIGTRAP-like events recognizer. If
2551 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2555 linux_nat_set_status_is_event (struct target_ops
*t
,
2556 int (*status_is_event
) (int status
))
2558 linux_nat_status_is_event
= status_is_event
;
2561 /* Wait until LP is stopped. */
2564 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2566 struct inferior
*inf
= find_inferior_pid (GET_PID (lp
->ptid
));
2568 /* If this is a vfork parent, bail out, it is not going to report
2569 any SIGSTOP until the vfork is done with. */
2570 if (inf
->vfork_child
!= NULL
)
2577 status
= wait_lwp (lp
);
2581 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2582 && WSTOPSIG (status
) == SIGINT
)
2584 lp
->ignore_sigint
= 0;
2587 ptrace (PTRACE_CONT
, GET_LWP (lp
->ptid
), 0, 0);
2588 if (debug_linux_nat
)
2589 fprintf_unfiltered (gdb_stdlog
,
2590 "PTRACE_CONT %s, 0, 0 (%s) "
2591 "(discarding SIGINT)\n",
2592 target_pid_to_str (lp
->ptid
),
2593 errno
? safe_strerror (errno
) : "OK");
2595 return stop_wait_callback (lp
, NULL
);
2598 maybe_clear_ignore_sigint (lp
);
2600 if (WSTOPSIG (status
) != SIGSTOP
)
2602 /* The thread was stopped with a signal other than SIGSTOP. */
2606 if (debug_linux_nat
)
2607 fprintf_unfiltered (gdb_stdlog
,
2608 "SWC: Pending event %s in %s\n",
2609 status_to_str ((int) status
),
2610 target_pid_to_str (lp
->ptid
));
2612 /* Save the sigtrap event. */
2613 lp
->status
= status
;
2614 gdb_assert (!lp
->stopped
);
2615 gdb_assert (lp
->signalled
);
2620 /* We caught the SIGSTOP that we intended to catch, so
2621 there's no SIGSTOP pending. */
2623 if (debug_linux_nat
)
2624 fprintf_unfiltered (gdb_stdlog
,
2625 "SWC: Delayed SIGSTOP caught for %s.\n",
2626 target_pid_to_str (lp
->ptid
));
2630 /* Reset SIGNALLED only after the stop_wait_callback call
2631 above as it does gdb_assert on SIGNALLED. */
2639 /* Return non-zero if LP has a wait status pending. */
2642 status_callback (struct lwp_info
*lp
, void *data
)
2644 /* Only report a pending wait status if we pretend that this has
2645 indeed been resumed. */
2649 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2651 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2652 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2653 0', so a clean process exit can not be stored pending in
2654 lp->status, it is indistinguishable from
2655 no-pending-status. */
2659 if (lp
->status
!= 0)
2665 /* Return non-zero if LP isn't stopped. */
2668 running_callback (struct lwp_info
*lp
, void *data
)
2670 return (!lp
->stopped
2671 || ((lp
->status
!= 0
2672 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2676 /* Count the LWP's that have had events. */
2679 count_events_callback (struct lwp_info
*lp
, void *data
)
2683 gdb_assert (count
!= NULL
);
2685 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2686 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2692 /* Select the LWP (if any) that is currently being single-stepped. */
2695 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2697 if (lp
->last_resume_kind
== resume_step
2704 /* Select the Nth LWP that has had a SIGTRAP event. */
2707 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2709 int *selector
= data
;
2711 gdb_assert (selector
!= NULL
);
2713 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2714 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2715 if ((*selector
)-- == 0)
2722 cancel_breakpoint (struct lwp_info
*lp
)
2724 /* Arrange for a breakpoint to be hit again later. We don't keep
2725 the SIGTRAP status and don't forward the SIGTRAP signal to the
2726 LWP. We will handle the current event, eventually we will resume
2727 this LWP, and this breakpoint will trap again.
2729 If we do not do this, then we run the risk that the user will
2730 delete or disable the breakpoint, but the LWP will have already
2733 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2734 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2737 pc
= regcache_read_pc (regcache
) - gdbarch_decr_pc_after_break (gdbarch
);
2738 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2740 if (debug_linux_nat
)
2741 fprintf_unfiltered (gdb_stdlog
,
2742 "CB: Push back breakpoint for %s\n",
2743 target_pid_to_str (lp
->ptid
));
2745 /* Back up the PC if necessary. */
2746 if (gdbarch_decr_pc_after_break (gdbarch
))
2747 regcache_write_pc (regcache
, pc
);
2755 cancel_breakpoints_callback (struct lwp_info
*lp
, void *data
)
2757 struct lwp_info
*event_lp
= data
;
2759 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2763 /* If a LWP other than the LWP that we're reporting an event for has
2764 hit a GDB breakpoint (as opposed to some random trap signal),
2765 then just arrange for it to hit it again later. We don't keep
2766 the SIGTRAP status and don't forward the SIGTRAP signal to the
2767 LWP. We will handle the current event, eventually we will resume
2768 all LWPs, and this one will get its breakpoint trap again.
2770 If we do not do this, then we run the risk that the user will
2771 delete or disable the breakpoint, but the LWP will have already
2774 if (linux_nat_lp_status_is_event (lp
)
2775 && cancel_breakpoint (lp
))
2776 /* Throw away the SIGTRAP. */
2782 /* Select one LWP out of those that have events pending. */
2785 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2788 int random_selector
;
2789 struct lwp_info
*event_lp
;
2791 /* Record the wait status for the original LWP. */
2792 (*orig_lp
)->status
= *status
;
2794 /* Give preference to any LWP that is being single-stepped. */
2795 event_lp
= iterate_over_lwps (filter
,
2796 select_singlestep_lwp_callback
, NULL
);
2797 if (event_lp
!= NULL
)
2799 if (debug_linux_nat
)
2800 fprintf_unfiltered (gdb_stdlog
,
2801 "SEL: Select single-step %s\n",
2802 target_pid_to_str (event_lp
->ptid
));
2806 /* No single-stepping LWP. Select one at random, out of those
2807 which have had SIGTRAP events. */
2809 /* First see how many SIGTRAP events we have. */
2810 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2812 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2813 random_selector
= (int)
2814 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2816 if (debug_linux_nat
&& num_events
> 1)
2817 fprintf_unfiltered (gdb_stdlog
,
2818 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2819 num_events
, random_selector
);
2821 event_lp
= iterate_over_lwps (filter
,
2822 select_event_lwp_callback
,
2826 if (event_lp
!= NULL
)
2828 /* Switch the event LWP. */
2829 *orig_lp
= event_lp
;
2830 *status
= event_lp
->status
;
2833 /* Flush the wait status for the event LWP. */
2834 (*orig_lp
)->status
= 0;
2837 /* Return non-zero if LP has been resumed. */
2840 resumed_callback (struct lwp_info
*lp
, void *data
)
2845 /* Stop an active thread, verify it still exists, then resume it. If
2846 the thread ends up with a pending status, then it is not resumed,
2847 and *DATA (really a pointer to int), is set. */
2850 stop_and_resume_callback (struct lwp_info
*lp
, void *data
)
2852 int *new_pending_p
= data
;
2856 ptid_t ptid
= lp
->ptid
;
2858 stop_callback (lp
, NULL
);
2859 stop_wait_callback (lp
, NULL
);
2861 /* Resume if the lwp still exists, and the core wanted it
2863 lp
= find_lwp_pid (ptid
);
2866 if (lp
->last_resume_kind
== resume_stop
2869 /* The core wanted the LWP to stop. Even if it stopped
2870 cleanly (with SIGSTOP), leave the event pending. */
2871 if (debug_linux_nat
)
2872 fprintf_unfiltered (gdb_stdlog
,
2873 "SARC: core wanted LWP %ld stopped "
2874 "(leaving SIGSTOP pending)\n",
2875 GET_LWP (lp
->ptid
));
2876 lp
->status
= W_STOPCODE (SIGSTOP
);
2879 if (lp
->status
== 0)
2881 if (debug_linux_nat
)
2882 fprintf_unfiltered (gdb_stdlog
,
2883 "SARC: re-resuming LWP %ld\n",
2884 GET_LWP (lp
->ptid
));
2885 resume_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2889 if (debug_linux_nat
)
2890 fprintf_unfiltered (gdb_stdlog
,
2891 "SARC: not re-resuming LWP %ld "
2893 GET_LWP (lp
->ptid
));
2902 /* Check if we should go on and pass this event to common code.
2903 Return the affected lwp if we are, or NULL otherwise. If we stop
2904 all lwps temporarily, we may end up with new pending events in some
2905 other lwp. In that case set *NEW_PENDING_P to true. */
2907 static struct lwp_info
*
2908 linux_nat_filter_event (int lwpid
, int status
, int *new_pending_p
)
2910 struct lwp_info
*lp
;
2914 lp
= find_lwp_pid (pid_to_ptid (lwpid
));
2916 /* Check for stop events reported by a process we didn't already
2917 know about - anything not already in our LWP list.
2919 If we're expecting to receive stopped processes after
2920 fork, vfork, and clone events, then we'll just add the
2921 new one to our list and go back to waiting for the event
2922 to be reported - the stopped process might be returned
2923 from waitpid before or after the event is.
2925 But note the case of a non-leader thread exec'ing after the
2926 leader having exited, and gone from our lists. The non-leader
2927 thread changes its tid to the tgid. */
2929 if (WIFSTOPPED (status
) && lp
== NULL
2930 && (WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 == PTRACE_EVENT_EXEC
))
2932 /* A multi-thread exec after we had seen the leader exiting. */
2933 if (debug_linux_nat
)
2934 fprintf_unfiltered (gdb_stdlog
,
2935 "LLW: Re-adding thread group leader LWP %d.\n",
2938 lp
= add_lwp (BUILD_LWP (lwpid
, lwpid
));
2941 add_thread (lp
->ptid
);
2944 if (WIFSTOPPED (status
) && !lp
)
2946 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2950 /* Make sure we don't report an event for the exit of an LWP not in
2951 our list, i.e. not part of the current process. This can happen
2952 if we detach from a program we originally forked and then it
2954 if (!WIFSTOPPED (status
) && !lp
)
2957 /* Handle GNU/Linux's syscall SIGTRAPs. */
2958 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2960 /* No longer need the sysgood bit. The ptrace event ends up
2961 recorded in lp->waitstatus if we care for it. We can carry
2962 on handling the event like a regular SIGTRAP from here
2964 status
= W_STOPCODE (SIGTRAP
);
2965 if (linux_handle_syscall_trap (lp
, 0))
2969 /* Handle GNU/Linux's extended waitstatus for trace events. */
2970 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2972 if (debug_linux_nat
)
2973 fprintf_unfiltered (gdb_stdlog
,
2974 "LLW: Handling extended status 0x%06x\n",
2976 if (linux_handle_extended_wait (lp
, status
, 0))
2980 if (linux_nat_status_is_event (status
))
2983 /* Check if the thread has exited. */
2984 if ((WIFEXITED (status
) || WIFSIGNALED (status
))
2985 && num_lwps (GET_PID (lp
->ptid
)) > 1)
2987 /* If this is the main thread, we must stop all threads and verify
2988 if they are still alive. This is because in the nptl thread model
2989 on Linux 2.4, there is no signal issued for exiting LWPs
2990 other than the main thread. We only get the main thread exit
2991 signal once all child threads have already exited. If we
2992 stop all the threads and use the stop_wait_callback to check
2993 if they have exited we can determine whether this signal
2994 should be ignored or whether it means the end of the debugged
2995 application, regardless of which threading model is being
2997 if (GET_PID (lp
->ptid
) == GET_LWP (lp
->ptid
))
3000 iterate_over_lwps (pid_to_ptid (GET_PID (lp
->ptid
)),
3001 stop_and_resume_callback
, new_pending_p
);
3004 if (debug_linux_nat
)
3005 fprintf_unfiltered (gdb_stdlog
,
3006 "LLW: %s exited.\n",
3007 target_pid_to_str (lp
->ptid
));
3009 if (num_lwps (GET_PID (lp
->ptid
)) > 1)
3011 /* If there is at least one more LWP, then the exit signal
3012 was not the end of the debugged application and should be
3019 /* Check if the current LWP has previously exited. In the nptl
3020 thread model, LWPs other than the main thread do not issue
3021 signals when they exit so we must check whenever the thread has
3022 stopped. A similar check is made in stop_wait_callback(). */
3023 if (num_lwps (GET_PID (lp
->ptid
)) > 1 && !linux_thread_alive (lp
->ptid
))
3025 ptid_t ptid
= pid_to_ptid (GET_PID (lp
->ptid
));
3027 if (debug_linux_nat
)
3028 fprintf_unfiltered (gdb_stdlog
,
3029 "LLW: %s exited.\n",
3030 target_pid_to_str (lp
->ptid
));
3034 /* Make sure there is at least one thread running. */
3035 gdb_assert (iterate_over_lwps (ptid
, running_callback
, NULL
));
3037 /* Discard the event. */
3041 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3042 an attempt to stop an LWP. */
3044 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3046 if (debug_linux_nat
)
3047 fprintf_unfiltered (gdb_stdlog
,
3048 "LLW: Delayed SIGSTOP caught for %s.\n",
3049 target_pid_to_str (lp
->ptid
));
3053 if (lp
->last_resume_kind
!= resume_stop
)
3055 /* This is a delayed SIGSTOP. */
3057 registers_changed ();
3059 if (linux_nat_prepare_to_resume
!= NULL
)
3060 linux_nat_prepare_to_resume (lp
);
3061 linux_ops
->to_resume (linux_ops
, pid_to_ptid (GET_LWP (lp
->ptid
)),
3062 lp
->step
, GDB_SIGNAL_0
);
3063 if (debug_linux_nat
)
3064 fprintf_unfiltered (gdb_stdlog
,
3065 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3067 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3068 target_pid_to_str (lp
->ptid
));
3071 gdb_assert (lp
->resumed
);
3073 /* Discard the event. */
3078 /* Make sure we don't report a SIGINT that we have already displayed
3079 for another thread. */
3080 if (lp
->ignore_sigint
3081 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3083 if (debug_linux_nat
)
3084 fprintf_unfiltered (gdb_stdlog
,
3085 "LLW: Delayed SIGINT caught for %s.\n",
3086 target_pid_to_str (lp
->ptid
));
3088 /* This is a delayed SIGINT. */
3089 lp
->ignore_sigint
= 0;
3091 registers_changed ();
3092 if (linux_nat_prepare_to_resume
!= NULL
)
3093 linux_nat_prepare_to_resume (lp
);
3094 linux_ops
->to_resume (linux_ops
, pid_to_ptid (GET_LWP (lp
->ptid
)),
3095 lp
->step
, GDB_SIGNAL_0
);
3096 if (debug_linux_nat
)
3097 fprintf_unfiltered (gdb_stdlog
,
3098 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3100 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3101 target_pid_to_str (lp
->ptid
));
3104 gdb_assert (lp
->resumed
);
3106 /* Discard the event. */
3110 /* An interesting event. */
3112 lp
->status
= status
;
3116 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3117 their exits until all other threads in the group have exited. */
3120 check_zombie_leaders (void)
3122 struct inferior
*inf
;
3126 struct lwp_info
*leader_lp
;
3131 leader_lp
= find_lwp_pid (pid_to_ptid (inf
->pid
));
3132 if (leader_lp
!= NULL
3133 /* Check if there are other threads in the group, as we may
3134 have raced with the inferior simply exiting. */
3135 && num_lwps (inf
->pid
) > 1
3136 && linux_proc_pid_is_zombie (inf
->pid
))
3138 if (debug_linux_nat
)
3139 fprintf_unfiltered (gdb_stdlog
,
3140 "CZL: Thread group leader %d zombie "
3141 "(it exited, or another thread execd).\n",
3144 /* A leader zombie can mean one of two things:
3146 - It exited, and there's an exit status pending
3147 available, or only the leader exited (not the whole
3148 program). In the latter case, we can't waitpid the
3149 leader's exit status until all other threads are gone.
3151 - There are 3 or more threads in the group, and a thread
3152 other than the leader exec'd. On an exec, the Linux
3153 kernel destroys all other threads (except the execing
3154 one) in the thread group, and resets the execing thread's
3155 tid to the tgid. No exit notification is sent for the
3156 execing thread -- from the ptracer's perspective, it
3157 appears as though the execing thread just vanishes.
3158 Until we reap all other threads except the leader and the
3159 execing thread, the leader will be zombie, and the
3160 execing thread will be in `D (disc sleep)'. As soon as
3161 all other threads are reaped, the execing thread changes
3162 it's tid to the tgid, and the previous (zombie) leader
3163 vanishes, giving place to the "new" leader. We could try
3164 distinguishing the exit and exec cases, by waiting once
3165 more, and seeing if something comes out, but it doesn't
3166 sound useful. The previous leader _does_ go away, and
3167 we'll re-add the new one once we see the exec event
3168 (which is just the same as what would happen if the
3169 previous leader did exit voluntarily before some other
3172 if (debug_linux_nat
)
3173 fprintf_unfiltered (gdb_stdlog
,
3174 "CZL: Thread group leader %d vanished.\n",
3176 exit_lwp (leader_lp
);
3182 linux_nat_wait_1 (struct target_ops
*ops
,
3183 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3186 static sigset_t prev_mask
;
3187 enum resume_kind last_resume_kind
;
3188 struct lwp_info
*lp
;
3191 if (debug_linux_nat
)
3192 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3194 /* The first time we get here after starting a new inferior, we may
3195 not have added it to the LWP list yet - this is the earliest
3196 moment at which we know its PID. */
3197 if (ptid_is_pid (inferior_ptid
))
3199 /* Upgrade the main thread's ptid. */
3200 thread_change_ptid (inferior_ptid
,
3201 BUILD_LWP (GET_PID (inferior_ptid
),
3202 GET_PID (inferior_ptid
)));
3204 lp
= add_initial_lwp (inferior_ptid
);
3208 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3209 block_child_signals (&prev_mask
);
3215 /* First check if there is a LWP with a wait status pending. */
3216 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3218 /* Any LWP in the PTID group that's been resumed will do. */
3219 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3222 if (debug_linux_nat
&& lp
->status
)
3223 fprintf_unfiltered (gdb_stdlog
,
3224 "LLW: Using pending wait status %s for %s.\n",
3225 status_to_str (lp
->status
),
3226 target_pid_to_str (lp
->ptid
));
3229 else if (is_lwp (ptid
))
3231 if (debug_linux_nat
)
3232 fprintf_unfiltered (gdb_stdlog
,
3233 "LLW: Waiting for specific LWP %s.\n",
3234 target_pid_to_str (ptid
));
3236 /* We have a specific LWP to check. */
3237 lp
= find_lwp_pid (ptid
);
3240 if (debug_linux_nat
&& lp
->status
)
3241 fprintf_unfiltered (gdb_stdlog
,
3242 "LLW: Using pending wait status %s for %s.\n",
3243 status_to_str (lp
->status
),
3244 target_pid_to_str (lp
->ptid
));
3246 /* We check for lp->waitstatus in addition to lp->status,
3247 because we can have pending process exits recorded in
3248 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3249 an additional lp->status_p flag. */
3250 if (lp
->status
== 0 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3254 if (!target_can_async_p ())
3256 /* Causes SIGINT to be passed on to the attached process. */
3260 /* But if we don't find a pending event, we'll have to wait. */
3266 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3269 - If the thread group leader exits while other threads in the
3270 thread group still exist, waitpid(TGID, ...) hangs. That
3271 waitpid won't return an exit status until the other threads
3272 in the group are reapped.
3274 - When a non-leader thread execs, that thread just vanishes
3275 without reporting an exit (so we'd hang if we waited for it
3276 explicitly in that case). The exec event is reported to
3280 lwpid
= my_waitpid (-1, &status
, __WCLONE
| WNOHANG
);
3281 if (lwpid
== 0 || (lwpid
== -1 && errno
== ECHILD
))
3282 lwpid
= my_waitpid (-1, &status
, WNOHANG
);
3284 if (debug_linux_nat
)
3285 fprintf_unfiltered (gdb_stdlog
,
3286 "LNW: waitpid(-1, ...) returned %d, %s\n",
3287 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3291 /* If this is true, then we paused LWPs momentarily, and may
3292 now have pending events to handle. */
3295 if (debug_linux_nat
)
3297 fprintf_unfiltered (gdb_stdlog
,
3298 "LLW: waitpid %ld received %s\n",
3299 (long) lwpid
, status_to_str (status
));
3302 lp
= linux_nat_filter_event (lwpid
, status
, &new_pending
);
3304 /* STATUS is now no longer valid, use LP->STATUS instead. */
3307 if (lp
&& !ptid_match (lp
->ptid
, ptid
))
3309 gdb_assert (lp
->resumed
);
3311 if (debug_linux_nat
)
3313 "LWP %ld got an event %06x, leaving pending.\n",
3314 ptid_get_lwp (lp
->ptid
), lp
->status
);
3316 if (WIFSTOPPED (lp
->status
))
3318 if (WSTOPSIG (lp
->status
) != SIGSTOP
)
3320 /* Cancel breakpoint hits. The breakpoint may
3321 be removed before we fetch events from this
3322 process to report to the core. It is best
3323 not to assume the moribund breakpoints
3324 heuristic always handles these cases --- it
3325 could be too many events go through to the
3326 core before this one is handled. All-stop
3327 always cancels breakpoint hits in all
3330 && linux_nat_lp_status_is_event (lp
)
3331 && cancel_breakpoint (lp
))
3333 /* Throw away the SIGTRAP. */
3336 if (debug_linux_nat
)
3338 "LLW: LWP %ld hit a breakpoint while"
3339 " waiting for another process;"
3341 ptid_get_lwp (lp
->ptid
));
3351 else if (WIFEXITED (lp
->status
) || WIFSIGNALED (lp
->status
))
3353 if (debug_linux_nat
)
3355 "Process %ld exited while stopping LWPs\n",
3356 ptid_get_lwp (lp
->ptid
));
3358 /* This was the last lwp in the process. Since
3359 events are serialized to GDB core, and we can't
3360 report this one right now, but GDB core and the
3361 other target layers will want to be notified
3362 about the exit code/signal, leave the status
3363 pending for the next time we're able to report
3366 /* Prevent trying to stop this thread again. We'll
3367 never try to resume it because it has a pending
3371 /* Dead LWP's aren't expected to reported a pending
3375 /* Store the pending event in the waitstatus as
3376 well, because W_EXITCODE(0,0) == 0. */
3377 store_waitstatus (&lp
->waitstatus
, lp
->status
);
3386 /* Some LWP now has a pending event. Go all the way
3387 back to check it. */
3393 /* We got an event to report to the core. */
3397 /* Retry until nothing comes out of waitpid. A single
3398 SIGCHLD can indicate more than one child stopped. */
3402 /* Check for zombie thread group leaders. Those can't be reaped
3403 until all other threads in the thread group are. */
3404 check_zombie_leaders ();
3406 /* If there are no resumed children left, bail. We'd be stuck
3407 forever in the sigsuspend call below otherwise. */
3408 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3410 if (debug_linux_nat
)
3411 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3413 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3415 if (!target_can_async_p ())
3416 clear_sigint_trap ();
3418 restore_child_signals_mask (&prev_mask
);
3419 return minus_one_ptid
;
3422 /* No interesting event to report to the core. */
3424 if (target_options
& TARGET_WNOHANG
)
3426 if (debug_linux_nat
)
3427 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3429 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3430 restore_child_signals_mask (&prev_mask
);
3431 return minus_one_ptid
;
3434 /* We shouldn't end up here unless we want to try again. */
3435 gdb_assert (lp
== NULL
);
3437 /* Block until we get an event reported with SIGCHLD. */
3438 sigsuspend (&suspend_mask
);
3441 if (!target_can_async_p ())
3442 clear_sigint_trap ();
3446 status
= lp
->status
;
3449 /* Don't report signals that GDB isn't interested in, such as
3450 signals that are neither printed nor stopped upon. Stopping all
3451 threads can be a bit time-consuming so if we want decent
3452 performance with heavily multi-threaded programs, especially when
3453 they're using a high frequency timer, we'd better avoid it if we
3456 if (WIFSTOPPED (status
))
3458 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3460 /* When using hardware single-step, we need to report every signal.
3461 Otherwise, signals in pass_mask may be short-circuited. */
3463 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
)))
3465 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3466 here? It is not clear we should. GDB may not expect
3467 other threads to run. On the other hand, not resuming
3468 newly attached threads may cause an unwanted delay in
3469 getting them running. */
3470 registers_changed ();
3471 if (linux_nat_prepare_to_resume
!= NULL
)
3472 linux_nat_prepare_to_resume (lp
);
3473 linux_ops
->to_resume (linux_ops
, pid_to_ptid (GET_LWP (lp
->ptid
)),
3475 if (debug_linux_nat
)
3476 fprintf_unfiltered (gdb_stdlog
,
3477 "LLW: %s %s, %s (preempt 'handle')\n",
3479 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3480 target_pid_to_str (lp
->ptid
),
3481 (signo
!= GDB_SIGNAL_0
3482 ? strsignal (gdb_signal_to_host (signo
))
3490 /* Only do the below in all-stop, as we currently use SIGINT
3491 to implement target_stop (see linux_nat_stop) in
3493 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3495 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3496 forwarded to the entire process group, that is, all LWPs
3497 will receive it - unless they're using CLONE_THREAD to
3498 share signals. Since we only want to report it once, we
3499 mark it as ignored for all LWPs except this one. */
3500 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid
)),
3501 set_ignore_sigint
, NULL
);
3502 lp
->ignore_sigint
= 0;
3505 maybe_clear_ignore_sigint (lp
);
3509 /* This LWP is stopped now. */
3512 if (debug_linux_nat
)
3513 fprintf_unfiltered (gdb_stdlog
, "LLW: Candidate event %s in %s.\n",
3514 status_to_str (status
), target_pid_to_str (lp
->ptid
));
3518 /* Now stop all other LWP's ... */
3519 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3521 /* ... and wait until all of them have reported back that
3522 they're no longer running. */
3523 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3525 /* If we're not waiting for a specific LWP, choose an event LWP
3526 from among those that have had events. Giving equal priority
3527 to all LWPs that have had events helps prevent
3529 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3530 select_event_lwp (ptid
, &lp
, &status
);
3532 /* Now that we've selected our final event LWP, cancel any
3533 breakpoints in other LWPs that have hit a GDB breakpoint.
3534 See the comment in cancel_breakpoints_callback to find out
3536 iterate_over_lwps (minus_one_ptid
, cancel_breakpoints_callback
, lp
);
3538 /* We'll need this to determine whether to report a SIGSTOP as
3539 TARGET_WAITKIND_0. Need to take a copy because
3540 resume_clear_callback clears it. */
3541 last_resume_kind
= lp
->last_resume_kind
;
3543 /* In all-stop, from the core's perspective, all LWPs are now
3544 stopped until a new resume action is sent over. */
3545 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3550 last_resume_kind
= lp
->last_resume_kind
;
3551 resume_clear_callback (lp
, NULL
);
3554 if (linux_nat_status_is_event (status
))
3556 if (debug_linux_nat
)
3557 fprintf_unfiltered (gdb_stdlog
,
3558 "LLW: trap ptid is %s.\n",
3559 target_pid_to_str (lp
->ptid
));
3562 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3564 *ourstatus
= lp
->waitstatus
;
3565 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3568 store_waitstatus (ourstatus
, status
);
3570 if (debug_linux_nat
)
3571 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3573 restore_child_signals_mask (&prev_mask
);
3575 if (last_resume_kind
== resume_stop
3576 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3577 && WSTOPSIG (status
) == SIGSTOP
)
3579 /* A thread that has been requested to stop by GDB with
3580 target_stop, and it stopped cleanly, so report as SIG0. The
3581 use of SIGSTOP is an implementation detail. */
3582 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3585 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3586 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3589 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3594 /* Resume LWPs that are currently stopped without any pending status
3595 to report, but are resumed from the core's perspective. */
3598 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3600 ptid_t
*wait_ptid_p
= data
;
3605 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3607 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3608 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3609 CORE_ADDR pc
= regcache_read_pc (regcache
);
3611 gdb_assert (is_executing (lp
->ptid
));
3613 /* Don't bother if there's a breakpoint at PC that we'd hit
3614 immediately, and we're not waiting for this LWP. */
3615 if (!ptid_match (lp
->ptid
, *wait_ptid_p
))
3617 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
3621 if (debug_linux_nat
)
3622 fprintf_unfiltered (gdb_stdlog
,
3623 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3624 target_pid_to_str (lp
->ptid
),
3625 paddress (gdbarch
, pc
),
3628 registers_changed ();
3629 if (linux_nat_prepare_to_resume
!= NULL
)
3630 linux_nat_prepare_to_resume (lp
);
3631 linux_ops
->to_resume (linux_ops
, pid_to_ptid (GET_LWP (lp
->ptid
)),
3632 lp
->step
, GDB_SIGNAL_0
);
3634 lp
->stopped_by_watchpoint
= 0;
3641 linux_nat_wait (struct target_ops
*ops
,
3642 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3647 if (debug_linux_nat
)
3649 char *options_string
;
3651 options_string
= target_options_to_string (target_options
);
3652 fprintf_unfiltered (gdb_stdlog
,
3653 "linux_nat_wait: [%s], [%s]\n",
3654 target_pid_to_str (ptid
),
3656 xfree (options_string
);
3659 /* Flush the async file first. */
3660 if (target_can_async_p ())
3661 async_file_flush ();
3663 /* Resume LWPs that are currently stopped without any pending status
3664 to report, but are resumed from the core's perspective. LWPs get
3665 in this state if we find them stopping at a time we're not
3666 interested in reporting the event (target_wait on a
3667 specific_process, for example, see linux_nat_wait_1), and
3668 meanwhile the event became uninteresting. Don't bother resuming
3669 LWPs we're not going to wait for if they'd stop immediately. */
3671 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3673 event_ptid
= linux_nat_wait_1 (ops
, ptid
, ourstatus
, target_options
);
3675 /* If we requested any event, and something came out, assume there
3676 may be more. If we requested a specific lwp or process, also
3677 assume there may be more. */
3678 if (target_can_async_p ()
3679 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3680 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3681 || !ptid_equal (ptid
, minus_one_ptid
)))
3684 /* Get ready for the next event. */
3685 if (target_can_async_p ())
3686 target_async (inferior_event_handler
, 0);
3692 kill_callback (struct lwp_info
*lp
, void *data
)
3694 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3697 kill (GET_LWP (lp
->ptid
), SIGKILL
);
3698 if (debug_linux_nat
)
3699 fprintf_unfiltered (gdb_stdlog
,
3700 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3701 target_pid_to_str (lp
->ptid
),
3702 errno
? safe_strerror (errno
) : "OK");
3704 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3707 ptrace (PTRACE_KILL
, GET_LWP (lp
->ptid
), 0, 0);
3708 if (debug_linux_nat
)
3709 fprintf_unfiltered (gdb_stdlog
,
3710 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3711 target_pid_to_str (lp
->ptid
),
3712 errno
? safe_strerror (errno
) : "OK");
3718 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3722 /* We must make sure that there are no pending events (delayed
3723 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3724 program doesn't interfere with any following debugging session. */
3726 /* For cloned processes we must check both with __WCLONE and
3727 without, since the exit status of a cloned process isn't reported
3733 pid
= my_waitpid (GET_LWP (lp
->ptid
), NULL
, __WCLONE
);
3734 if (pid
!= (pid_t
) -1)
3736 if (debug_linux_nat
)
3737 fprintf_unfiltered (gdb_stdlog
,
3738 "KWC: wait %s received unknown.\n",
3739 target_pid_to_str (lp
->ptid
));
3740 /* The Linux kernel sometimes fails to kill a thread
3741 completely after PTRACE_KILL; that goes from the stop
3742 point in do_fork out to the one in
3743 get_signal_to_deliever and waits again. So kill it
3745 kill_callback (lp
, NULL
);
3748 while (pid
== GET_LWP (lp
->ptid
));
3750 gdb_assert (pid
== -1 && errno
== ECHILD
);
3755 pid
= my_waitpid (GET_LWP (lp
->ptid
), NULL
, 0);
3756 if (pid
!= (pid_t
) -1)
3758 if (debug_linux_nat
)
3759 fprintf_unfiltered (gdb_stdlog
,
3760 "KWC: wait %s received unk.\n",
3761 target_pid_to_str (lp
->ptid
));
3762 /* See the call to kill_callback above. */
3763 kill_callback (lp
, NULL
);
3766 while (pid
== GET_LWP (lp
->ptid
));
3768 gdb_assert (pid
== -1 && errno
== ECHILD
);
3773 linux_nat_kill (struct target_ops
*ops
)
3775 struct target_waitstatus last
;
3779 /* If we're stopped while forking and we haven't followed yet,
3780 kill the other task. We need to do this first because the
3781 parent will be sleeping if this is a vfork. */
3783 get_last_target_status (&last_ptid
, &last
);
3785 if (last
.kind
== TARGET_WAITKIND_FORKED
3786 || last
.kind
== TARGET_WAITKIND_VFORKED
)
3788 ptrace (PT_KILL
, PIDGET (last
.value
.related_pid
), 0, 0);
3791 /* Let the arch-specific native code know this process is
3793 linux_nat_forget_process (PIDGET (last
.value
.related_pid
));
3796 if (forks_exist_p ())
3797 linux_fork_killall ();
3800 ptid_t ptid
= pid_to_ptid (ptid_get_pid (inferior_ptid
));
3802 /* Stop all threads before killing them, since ptrace requires
3803 that the thread is stopped to sucessfully PTRACE_KILL. */
3804 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3805 /* ... and wait until all of them have reported back that
3806 they're no longer running. */
3807 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3809 /* Kill all LWP's ... */
3810 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3812 /* ... and wait until we've flushed all events. */
3813 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3816 target_mourn_inferior ();
3820 linux_nat_mourn_inferior (struct target_ops
*ops
)
3822 int pid
= ptid_get_pid (inferior_ptid
);
3824 purge_lwp_list (pid
);
3826 if (! forks_exist_p ())
3827 /* Normal case, no other forks available. */
3828 linux_ops
->to_mourn_inferior (ops
);
3830 /* Multi-fork case. The current inferior_ptid has exited, but
3831 there are other viable forks to debug. Delete the exiting
3832 one and context-switch to the first available. */
3833 linux_fork_mourn_inferior ();
3835 /* Let the arch-specific native code know this process is gone. */
3836 linux_nat_forget_process (pid
);
3839 /* Convert a native/host siginfo object, into/from the siginfo in the
3840 layout of the inferiors' architecture. */
3843 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3847 if (linux_nat_siginfo_fixup
!= NULL
)
3848 done
= linux_nat_siginfo_fixup (siginfo
, inf_siginfo
, direction
);
3850 /* If there was no callback, or the callback didn't do anything,
3851 then just do a straight memcpy. */
3855 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3857 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3862 linux_xfer_siginfo (struct target_ops
*ops
, enum target_object object
,
3863 const char *annex
, gdb_byte
*readbuf
,
3864 const gdb_byte
*writebuf
, ULONGEST offset
, LONGEST len
)
3868 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3870 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3871 gdb_assert (readbuf
|| writebuf
);
3873 pid
= GET_LWP (inferior_ptid
);
3875 pid
= GET_PID (inferior_ptid
);
3877 if (offset
> sizeof (siginfo
))
3881 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3885 /* When GDB is built as a 64-bit application, ptrace writes into
3886 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3887 inferior with a 64-bit GDB should look the same as debugging it
3888 with a 32-bit GDB, we need to convert it. GDB core always sees
3889 the converted layout, so any read/write will have to be done
3891 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3893 if (offset
+ len
> sizeof (siginfo
))
3894 len
= sizeof (siginfo
) - offset
;
3896 if (readbuf
!= NULL
)
3897 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3900 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3902 /* Convert back to ptrace layout before flushing it out. */
3903 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3906 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3915 linux_nat_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3916 const char *annex
, gdb_byte
*readbuf
,
3917 const gdb_byte
*writebuf
,
3918 ULONGEST offset
, LONGEST len
)
3920 struct cleanup
*old_chain
;
3923 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3924 return linux_xfer_siginfo (ops
, object
, annex
, readbuf
, writebuf
,
3927 /* The target is connected but no live inferior is selected. Pass
3928 this request down to a lower stratum (e.g., the executable
3930 if (object
== TARGET_OBJECT_MEMORY
&& ptid_equal (inferior_ptid
, null_ptid
))
3933 old_chain
= save_inferior_ptid ();
3935 if (is_lwp (inferior_ptid
))
3936 inferior_ptid
= pid_to_ptid (GET_LWP (inferior_ptid
));
3938 xfer
= linux_ops
->to_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
3941 do_cleanups (old_chain
);
3946 linux_thread_alive (ptid_t ptid
)
3950 gdb_assert (is_lwp (ptid
));
3952 /* Send signal 0 instead of anything ptrace, because ptracing a
3953 running thread errors out claiming that the thread doesn't
3955 err
= kill_lwp (GET_LWP (ptid
), 0);
3957 if (debug_linux_nat
)
3958 fprintf_unfiltered (gdb_stdlog
,
3959 "LLTA: KILL(SIG0) %s (%s)\n",
3960 target_pid_to_str (ptid
),
3961 err
? safe_strerror (tmp_errno
) : "OK");
3970 linux_nat_thread_alive (struct target_ops
*ops
, ptid_t ptid
)
3972 return linux_thread_alive (ptid
);
3976 linux_nat_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
3978 static char buf
[64];
3981 && (GET_PID (ptid
) != GET_LWP (ptid
)
3982 || num_lwps (GET_PID (ptid
)) > 1))
3984 snprintf (buf
, sizeof (buf
), "LWP %ld", GET_LWP (ptid
));
3988 return normal_pid_to_str (ptid
);
3992 linux_nat_thread_name (struct thread_info
*thr
)
3994 int pid
= ptid_get_pid (thr
->ptid
);
3995 long lwp
= ptid_get_lwp (thr
->ptid
);
3996 #define FORMAT "/proc/%d/task/%ld/comm"
3997 char buf
[sizeof (FORMAT
) + 30];
3999 char *result
= NULL
;
4001 snprintf (buf
, sizeof (buf
), FORMAT
, pid
, lwp
);
4002 comm_file
= gdb_fopen_cloexec (buf
, "r");
4005 /* Not exported by the kernel, so we define it here. */
4007 static char line
[COMM_LEN
+ 1];
4009 if (fgets (line
, sizeof (line
), comm_file
))
4011 char *nl
= strchr (line
, '\n');
4028 /* Accepts an integer PID; Returns a string representing a file that
4029 can be opened to get the symbols for the child process. */
4032 linux_child_pid_to_exec_file (int pid
)
4034 char *name1
, *name2
;
4036 name1
= xmalloc (PATH_MAX
);
4037 name2
= xmalloc (PATH_MAX
);
4038 make_cleanup (xfree
, name1
);
4039 make_cleanup (xfree
, name2
);
4040 memset (name2
, 0, PATH_MAX
);
4042 sprintf (name1
, "/proc/%d/exe", pid
);
4043 if (readlink (name1
, name2
, PATH_MAX
- 1) > 0)
4049 /* Records the thread's register state for the corefile note
4053 linux_nat_collect_thread_registers (const struct regcache
*regcache
,
4054 ptid_t ptid
, bfd
*obfd
,
4055 char *note_data
, int *note_size
,
4056 enum gdb_signal stop_signal
)
4058 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
4059 const struct regset
*regset
;
4061 gdb_gregset_t gregs
;
4062 gdb_fpregset_t fpregs
;
4064 core_regset_p
= gdbarch_regset_from_core_section_p (gdbarch
);
4067 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg",
4069 != NULL
&& regset
->collect_regset
!= NULL
)
4070 regset
->collect_regset (regset
, regcache
, -1, &gregs
, sizeof (gregs
));
4072 fill_gregset (regcache
, &gregs
, -1);
4074 note_data
= (char *) elfcore_write_prstatus
4075 (obfd
, note_data
, note_size
, ptid_get_lwp (ptid
),
4076 gdb_signal_to_host (stop_signal
), &gregs
);
4079 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg2",
4081 != NULL
&& regset
->collect_regset
!= NULL
)
4082 regset
->collect_regset (regset
, regcache
, -1, &fpregs
, sizeof (fpregs
));
4084 fill_fpregset (regcache
, &fpregs
, -1);
4086 note_data
= (char *) elfcore_write_prfpreg (obfd
, note_data
, note_size
,
4087 &fpregs
, sizeof (fpregs
));
4092 /* Fills the "to_make_corefile_note" target vector. Builds the note
4093 section for a corefile, and returns it in a malloc buffer. */
4096 linux_nat_make_corefile_notes (bfd
*obfd
, int *note_size
)
4098 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4099 converted to gdbarch_core_regset_sections, this function can go away. */
4100 return linux_make_corefile_notes (target_gdbarch (), obfd
, note_size
,
4101 linux_nat_collect_thread_registers
);
4104 /* Implement the to_xfer_partial interface for memory reads using the /proc
4105 filesystem. Because we can use a single read() call for /proc, this
4106 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4107 but it doesn't support writes. */
4110 linux_proc_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4111 const char *annex
, gdb_byte
*readbuf
,
4112 const gdb_byte
*writebuf
,
4113 ULONGEST offset
, LONGEST len
)
4119 if (object
!= TARGET_OBJECT_MEMORY
|| !readbuf
)
4122 /* Don't bother for one word. */
4123 if (len
< 3 * sizeof (long))
4126 /* We could keep this file open and cache it - possibly one per
4127 thread. That requires some juggling, but is even faster. */
4128 sprintf (filename
, "/proc/%d/mem", PIDGET (inferior_ptid
));
4129 fd
= gdb_open_cloexec (filename
, O_RDONLY
| O_LARGEFILE
, 0);
4133 /* If pread64 is available, use it. It's faster if the kernel
4134 supports it (only one syscall), and it's 64-bit safe even on
4135 32-bit platforms (for instance, SPARC debugging a SPARC64
4138 if (pread64 (fd
, readbuf
, len
, offset
) != len
)
4140 if (lseek (fd
, offset
, SEEK_SET
) == -1 || read (fd
, readbuf
, len
) != len
)
4151 /* Enumerate spufs IDs for process PID. */
4153 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, LONGEST len
)
4155 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
4157 LONGEST written
= 0;
4160 struct dirent
*entry
;
4162 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
4163 dir
= opendir (path
);
4168 while ((entry
= readdir (dir
)) != NULL
)
4174 fd
= atoi (entry
->d_name
);
4178 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
4179 if (stat (path
, &st
) != 0)
4181 if (!S_ISDIR (st
.st_mode
))
4184 if (statfs (path
, &stfs
) != 0)
4186 if (stfs
.f_type
!= SPUFS_MAGIC
)
4189 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
4191 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
4201 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4202 object type, using the /proc file system. */
4204 linux_proc_xfer_spu (struct target_ops
*ops
, enum target_object object
,
4205 const char *annex
, gdb_byte
*readbuf
,
4206 const gdb_byte
*writebuf
,
4207 ULONGEST offset
, LONGEST len
)
4212 int pid
= PIDGET (inferior_ptid
);
4219 return spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4222 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4223 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4228 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4235 ret
= write (fd
, writebuf
, (size_t) len
);
4237 ret
= read (fd
, readbuf
, (size_t) len
);
4244 /* Parse LINE as a signal set and add its set bits to SIGS. */
4247 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4249 int len
= strlen (line
) - 1;
4253 if (line
[len
] != '\n')
4254 error (_("Could not parse signal set: %s"), line
);
4262 if (*p
>= '0' && *p
<= '9')
4264 else if (*p
>= 'a' && *p
<= 'f')
4265 digit
= *p
- 'a' + 10;
4267 error (_("Could not parse signal set: %s"), line
);
4272 sigaddset (sigs
, signum
+ 1);
4274 sigaddset (sigs
, signum
+ 2);
4276 sigaddset (sigs
, signum
+ 3);
4278 sigaddset (sigs
, signum
+ 4);
4284 /* Find process PID's pending signals from /proc/pid/status and set
4288 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4289 sigset_t
*blocked
, sigset_t
*ignored
)
4292 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4293 struct cleanup
*cleanup
;
4295 sigemptyset (pending
);
4296 sigemptyset (blocked
);
4297 sigemptyset (ignored
);
4298 sprintf (fname
, "/proc/%d/status", pid
);
4299 procfile
= gdb_fopen_cloexec (fname
, "r");
4300 if (procfile
== NULL
)
4301 error (_("Could not open %s"), fname
);
4302 cleanup
= make_cleanup_fclose (procfile
);
4304 while (fgets (buffer
, PATH_MAX
, procfile
) != NULL
)
4306 /* Normal queued signals are on the SigPnd line in the status
4307 file. However, 2.6 kernels also have a "shared" pending
4308 queue for delivering signals to a thread group, so check for
4311 Unfortunately some Red Hat kernels include the shared pending
4312 queue but not the ShdPnd status field. */
4314 if (strncmp (buffer
, "SigPnd:\t", 8) == 0)
4315 add_line_to_sigset (buffer
+ 8, pending
);
4316 else if (strncmp (buffer
, "ShdPnd:\t", 8) == 0)
4317 add_line_to_sigset (buffer
+ 8, pending
);
4318 else if (strncmp (buffer
, "SigBlk:\t", 8) == 0)
4319 add_line_to_sigset (buffer
+ 8, blocked
);
4320 else if (strncmp (buffer
, "SigIgn:\t", 8) == 0)
4321 add_line_to_sigset (buffer
+ 8, ignored
);
4324 do_cleanups (cleanup
);
4328 linux_nat_xfer_osdata (struct target_ops
*ops
, enum target_object object
,
4329 const char *annex
, gdb_byte
*readbuf
,
4330 const gdb_byte
*writebuf
, ULONGEST offset
, LONGEST len
)
4332 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4334 return linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4338 linux_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4339 const char *annex
, gdb_byte
*readbuf
,
4340 const gdb_byte
*writebuf
, ULONGEST offset
, LONGEST len
)
4344 if (object
== TARGET_OBJECT_AUXV
)
4345 return memory_xfer_auxv (ops
, object
, annex
, readbuf
, writebuf
,
4348 if (object
== TARGET_OBJECT_OSDATA
)
4349 return linux_nat_xfer_osdata (ops
, object
, annex
, readbuf
, writebuf
,
4352 if (object
== TARGET_OBJECT_SPU
)
4353 return linux_proc_xfer_spu (ops
, object
, annex
, readbuf
, writebuf
,
4356 /* GDB calculates all the addresses in possibly larget width of the address.
4357 Address width needs to be masked before its final use - either by
4358 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4360 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4362 if (object
== TARGET_OBJECT_MEMORY
)
4364 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
4366 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
4367 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
4370 xfer
= linux_proc_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4375 return super_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4380 cleanup_target_stop (void *arg
)
4382 ptid_t
*ptid
= (ptid_t
*) arg
;
4384 gdb_assert (arg
!= NULL
);
4387 target_resume (*ptid
, 0, GDB_SIGNAL_0
);
4390 static VEC(static_tracepoint_marker_p
) *
4391 linux_child_static_tracepoint_markers_by_strid (const char *strid
)
4393 char s
[IPA_CMD_BUF_SIZE
];
4394 struct cleanup
*old_chain
;
4395 int pid
= ptid_get_pid (inferior_ptid
);
4396 VEC(static_tracepoint_marker_p
) *markers
= NULL
;
4397 struct static_tracepoint_marker
*marker
= NULL
;
4399 ptid_t ptid
= ptid_build (pid
, 0, 0);
4404 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4405 s
[sizeof ("qTfSTM")] = 0;
4407 agent_run_command (pid
, s
, strlen (s
) + 1);
4409 old_chain
= make_cleanup (free_current_marker
, &marker
);
4410 make_cleanup (cleanup_target_stop
, &ptid
);
4415 marker
= XCNEW (struct static_tracepoint_marker
);
4419 parse_static_tracepoint_marker_definition (p
, &p
, marker
);
4421 if (strid
== NULL
|| strcmp (strid
, marker
->str_id
) == 0)
4423 VEC_safe_push (static_tracepoint_marker_p
,
4429 release_static_tracepoint_marker (marker
);
4430 memset (marker
, 0, sizeof (*marker
));
4433 while (*p
++ == ','); /* comma-separated list */
4435 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4436 s
[sizeof ("qTsSTM")] = 0;
4437 agent_run_command (pid
, s
, strlen (s
) + 1);
4441 do_cleanups (old_chain
);
4446 /* Create a prototype generic GNU/Linux target. The client can override
4447 it with local methods. */
4450 linux_target_install_ops (struct target_ops
*t
)
4452 t
->to_insert_fork_catchpoint
= linux_child_insert_fork_catchpoint
;
4453 t
->to_remove_fork_catchpoint
= linux_child_remove_fork_catchpoint
;
4454 t
->to_insert_vfork_catchpoint
= linux_child_insert_vfork_catchpoint
;
4455 t
->to_remove_vfork_catchpoint
= linux_child_remove_vfork_catchpoint
;
4456 t
->to_insert_exec_catchpoint
= linux_child_insert_exec_catchpoint
;
4457 t
->to_remove_exec_catchpoint
= linux_child_remove_exec_catchpoint
;
4458 t
->to_set_syscall_catchpoint
= linux_child_set_syscall_catchpoint
;
4459 t
->to_pid_to_exec_file
= linux_child_pid_to_exec_file
;
4460 t
->to_post_startup_inferior
= linux_child_post_startup_inferior
;
4461 t
->to_post_attach
= linux_child_post_attach
;
4462 t
->to_follow_fork
= linux_child_follow_fork
;
4463 t
->to_make_corefile_notes
= linux_nat_make_corefile_notes
;
4465 super_xfer_partial
= t
->to_xfer_partial
;
4466 t
->to_xfer_partial
= linux_xfer_partial
;
4468 t
->to_static_tracepoint_markers_by_strid
4469 = linux_child_static_tracepoint_markers_by_strid
;
4475 struct target_ops
*t
;
4477 t
= inf_ptrace_target ();
4478 linux_target_install_ops (t
);
4484 linux_trad_target (CORE_ADDR (*register_u_offset
)(struct gdbarch
*, int, int))
4486 struct target_ops
*t
;
4488 t
= inf_ptrace_trad_target (register_u_offset
);
4489 linux_target_install_ops (t
);
4494 /* target_is_async_p implementation. */
4497 linux_nat_is_async_p (void)
4499 /* NOTE: palves 2008-03-21: We're only async when the user requests
4500 it explicitly with the "set target-async" command.
4501 Someday, linux will always be async. */
4502 return target_async_permitted
;
4505 /* target_can_async_p implementation. */
4508 linux_nat_can_async_p (void)
4510 /* NOTE: palves 2008-03-21: We're only async when the user requests
4511 it explicitly with the "set target-async" command.
4512 Someday, linux will always be async. */
4513 return target_async_permitted
;
4517 linux_nat_supports_non_stop (void)
4522 /* True if we want to support multi-process. To be removed when GDB
4523 supports multi-exec. */
4525 int linux_multi_process
= 1;
4528 linux_nat_supports_multi_process (void)
4530 return linux_multi_process
;
4534 linux_nat_supports_disable_randomization (void)
4536 #ifdef HAVE_PERSONALITY
4543 static int async_terminal_is_ours
= 1;
4545 /* target_terminal_inferior implementation. */
4548 linux_nat_terminal_inferior (void)
4550 if (!target_is_async_p ())
4552 /* Async mode is disabled. */
4553 terminal_inferior ();
4557 terminal_inferior ();
4559 /* Calls to target_terminal_*() are meant to be idempotent. */
4560 if (!async_terminal_is_ours
)
4563 delete_file_handler (input_fd
);
4564 async_terminal_is_ours
= 0;
4568 /* target_terminal_ours implementation. */
4571 linux_nat_terminal_ours (void)
4573 if (!target_is_async_p ())
4575 /* Async mode is disabled. */
4580 /* GDB should never give the terminal to the inferior if the
4581 inferior is running in the background (run&, continue&, etc.),
4582 but claiming it sure should. */
4585 if (async_terminal_is_ours
)
4588 clear_sigint_trap ();
4589 add_file_handler (input_fd
, stdin_event_handler
, 0);
4590 async_terminal_is_ours
= 1;
4593 static void (*async_client_callback
) (enum inferior_event_type event_type
,
4595 static void *async_client_context
;
4597 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4598 so we notice when any child changes state, and notify the
4599 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4600 above to wait for the arrival of a SIGCHLD. */
4603 sigchld_handler (int signo
)
4605 int old_errno
= errno
;
4607 if (debug_linux_nat
)
4608 ui_file_write_async_safe (gdb_stdlog
,
4609 "sigchld\n", sizeof ("sigchld\n") - 1);
4611 if (signo
== SIGCHLD
4612 && linux_nat_event_pipe
[0] != -1)
4613 async_file_mark (); /* Let the event loop know that there are
4614 events to handle. */
4619 /* Callback registered with the target events file descriptor. */
4622 handle_target_event (int error
, gdb_client_data client_data
)
4624 (*async_client_callback
) (INF_REG_EVENT
, async_client_context
);
4627 /* Create/destroy the target events pipe. Returns previous state. */
4630 linux_async_pipe (int enable
)
4632 int previous
= (linux_nat_event_pipe
[0] != -1);
4634 if (previous
!= enable
)
4638 /* Block child signals while we create/destroy the pipe, as
4639 their handler writes to it. */
4640 block_child_signals (&prev_mask
);
4644 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4645 internal_error (__FILE__
, __LINE__
,
4646 "creating event pipe failed.");
4648 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4649 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4653 close (linux_nat_event_pipe
[0]);
4654 close (linux_nat_event_pipe
[1]);
4655 linux_nat_event_pipe
[0] = -1;
4656 linux_nat_event_pipe
[1] = -1;
4659 restore_child_signals_mask (&prev_mask
);
4665 /* target_async implementation. */
4668 linux_nat_async (void (*callback
) (enum inferior_event_type event_type
,
4669 void *context
), void *context
)
4671 if (callback
!= NULL
)
4673 async_client_callback
= callback
;
4674 async_client_context
= context
;
4675 if (!linux_async_pipe (1))
4677 add_file_handler (linux_nat_event_pipe
[0],
4678 handle_target_event
, NULL
);
4679 /* There may be pending events to handle. Tell the event loop
4686 async_client_callback
= callback
;
4687 async_client_context
= context
;
4688 delete_file_handler (linux_nat_event_pipe
[0]);
4689 linux_async_pipe (0);
4694 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4698 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4702 if (debug_linux_nat
)
4703 fprintf_unfiltered (gdb_stdlog
,
4704 "LNSL: running -> suspending %s\n",
4705 target_pid_to_str (lwp
->ptid
));
4708 if (lwp
->last_resume_kind
== resume_stop
)
4710 if (debug_linux_nat
)
4711 fprintf_unfiltered (gdb_stdlog
,
4712 "linux-nat: already stopping LWP %ld at "
4714 ptid_get_lwp (lwp
->ptid
));
4718 stop_callback (lwp
, NULL
);
4719 lwp
->last_resume_kind
= resume_stop
;
4723 /* Already known to be stopped; do nothing. */
4725 if (debug_linux_nat
)
4727 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4728 fprintf_unfiltered (gdb_stdlog
,
4729 "LNSL: already stopped/stop_requested %s\n",
4730 target_pid_to_str (lwp
->ptid
));
4732 fprintf_unfiltered (gdb_stdlog
,
4733 "LNSL: already stopped/no "
4734 "stop_requested yet %s\n",
4735 target_pid_to_str (lwp
->ptid
));
4742 linux_nat_stop (ptid_t ptid
)
4745 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4747 linux_ops
->to_stop (ptid
);
4751 linux_nat_close (void)
4753 /* Unregister from the event loop. */
4754 if (linux_nat_is_async_p ())
4755 linux_nat_async (NULL
, 0);
4757 if (linux_ops
->to_close
)
4758 linux_ops
->to_close ();
4761 /* When requests are passed down from the linux-nat layer to the
4762 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4763 used. The address space pointer is stored in the inferior object,
4764 but the common code that is passed such ptid can't tell whether
4765 lwpid is a "main" process id or not (it assumes so). We reverse
4766 look up the "main" process id from the lwp here. */
4768 static struct address_space
*
4769 linux_nat_thread_address_space (struct target_ops
*t
, ptid_t ptid
)
4771 struct lwp_info
*lwp
;
4772 struct inferior
*inf
;
4775 pid
= GET_LWP (ptid
);
4776 if (GET_LWP (ptid
) == 0)
4778 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4780 lwp
= find_lwp_pid (ptid
);
4781 pid
= GET_PID (lwp
->ptid
);
4785 /* A (pid,lwpid,0) ptid. */
4786 pid
= GET_PID (ptid
);
4789 inf
= find_inferior_pid (pid
);
4790 gdb_assert (inf
!= NULL
);
4794 /* Return the cached value of the processor core for thread PTID. */
4797 linux_nat_core_of_thread (struct target_ops
*ops
, ptid_t ptid
)
4799 struct lwp_info
*info
= find_lwp_pid (ptid
);
4807 linux_nat_add_target (struct target_ops
*t
)
4809 /* Save the provided single-threaded target. We save this in a separate
4810 variable because another target we've inherited from (e.g. inf-ptrace)
4811 may have saved a pointer to T; we want to use it for the final
4812 process stratum target. */
4813 linux_ops_saved
= *t
;
4814 linux_ops
= &linux_ops_saved
;
4816 /* Override some methods for multithreading. */
4817 t
->to_create_inferior
= linux_nat_create_inferior
;
4818 t
->to_attach
= linux_nat_attach
;
4819 t
->to_detach
= linux_nat_detach
;
4820 t
->to_resume
= linux_nat_resume
;
4821 t
->to_wait
= linux_nat_wait
;
4822 t
->to_pass_signals
= linux_nat_pass_signals
;
4823 t
->to_xfer_partial
= linux_nat_xfer_partial
;
4824 t
->to_kill
= linux_nat_kill
;
4825 t
->to_mourn_inferior
= linux_nat_mourn_inferior
;
4826 t
->to_thread_alive
= linux_nat_thread_alive
;
4827 t
->to_pid_to_str
= linux_nat_pid_to_str
;
4828 t
->to_thread_name
= linux_nat_thread_name
;
4829 t
->to_has_thread_control
= tc_schedlock
;
4830 t
->to_thread_address_space
= linux_nat_thread_address_space
;
4831 t
->to_stopped_by_watchpoint
= linux_nat_stopped_by_watchpoint
;
4832 t
->to_stopped_data_address
= linux_nat_stopped_data_address
;
4834 t
->to_can_async_p
= linux_nat_can_async_p
;
4835 t
->to_is_async_p
= linux_nat_is_async_p
;
4836 t
->to_supports_non_stop
= linux_nat_supports_non_stop
;
4837 t
->to_async
= linux_nat_async
;
4838 t
->to_terminal_inferior
= linux_nat_terminal_inferior
;
4839 t
->to_terminal_ours
= linux_nat_terminal_ours
;
4840 t
->to_close
= linux_nat_close
;
4842 /* Methods for non-stop support. */
4843 t
->to_stop
= linux_nat_stop
;
4845 t
->to_supports_multi_process
= linux_nat_supports_multi_process
;
4847 t
->to_supports_disable_randomization
4848 = linux_nat_supports_disable_randomization
;
4850 t
->to_core_of_thread
= linux_nat_core_of_thread
;
4852 /* We don't change the stratum; this target will sit at
4853 process_stratum and thread_db will set at thread_stratum. This
4854 is a little strange, since this is a multi-threaded-capable
4855 target, but we want to be on the stack below thread_db, and we
4856 also want to be used for single-threaded processes. */
4861 /* Register a method to call whenever a new thread is attached. */
4863 linux_nat_set_new_thread (struct target_ops
*t
,
4864 void (*new_thread
) (struct lwp_info
*))
4866 /* Save the pointer. We only support a single registered instance
4867 of the GNU/Linux native target, so we do not need to map this to
4869 linux_nat_new_thread
= new_thread
;
4872 /* See declaration in linux-nat.h. */
4875 linux_nat_set_new_fork (struct target_ops
*t
,
4876 linux_nat_new_fork_ftype
*new_fork
)
4878 /* Save the pointer. */
4879 linux_nat_new_fork
= new_fork
;
4882 /* See declaration in linux-nat.h. */
4885 linux_nat_set_forget_process (struct target_ops
*t
,
4886 linux_nat_forget_process_ftype
*fn
)
4888 /* Save the pointer. */
4889 linux_nat_forget_process_hook
= fn
;
4892 /* See declaration in linux-nat.h. */
4895 linux_nat_forget_process (pid_t pid
)
4897 if (linux_nat_forget_process_hook
!= NULL
)
4898 linux_nat_forget_process_hook (pid
);
4901 /* Register a method that converts a siginfo object between the layout
4902 that ptrace returns, and the layout in the architecture of the
4905 linux_nat_set_siginfo_fixup (struct target_ops
*t
,
4906 int (*siginfo_fixup
) (siginfo_t
*,
4910 /* Save the pointer. */
4911 linux_nat_siginfo_fixup
= siginfo_fixup
;
4914 /* Register a method to call prior to resuming a thread. */
4917 linux_nat_set_prepare_to_resume (struct target_ops
*t
,
4918 void (*prepare_to_resume
) (struct lwp_info
*))
4920 /* Save the pointer. */
4921 linux_nat_prepare_to_resume
= prepare_to_resume
;
4924 /* See linux-nat.h. */
4927 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4931 pid
= GET_LWP (ptid
);
4933 pid
= GET_PID (ptid
);
4936 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4939 memset (siginfo
, 0, sizeof (*siginfo
));
4945 /* Provide a prototype to silence -Wmissing-prototypes. */
4946 extern initialize_file_ftype _initialize_linux_nat
;
4949 _initialize_linux_nat (void)
4951 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4952 &debug_linux_nat
, _("\
4953 Set debugging of GNU/Linux lwp module."), _("\
4954 Show debugging of GNU/Linux lwp module."), _("\
4955 Enables printf debugging output."),
4957 show_debug_linux_nat
,
4958 &setdebuglist
, &showdebuglist
);
4960 /* Save this mask as the default. */
4961 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
4963 /* Install a SIGCHLD handler. */
4964 sigchld_action
.sa_handler
= sigchld_handler
;
4965 sigemptyset (&sigchld_action
.sa_mask
);
4966 sigchld_action
.sa_flags
= SA_RESTART
;
4968 /* Make it the default. */
4969 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4971 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4972 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
4973 sigdelset (&suspend_mask
, SIGCHLD
);
4975 sigemptyset (&blocked_mask
);
4979 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4980 the GNU/Linux Threads library and therefore doesn't really belong
4983 /* Read variable NAME in the target and return its value if found.
4984 Otherwise return zero. It is assumed that the type of the variable
4988 get_signo (const char *name
)
4990 struct minimal_symbol
*ms
;
4993 ms
= lookup_minimal_symbol (name
, NULL
, NULL
);
4997 if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms
), (gdb_byte
*) &signo
,
4998 sizeof (signo
)) != 0)
5004 /* Return the set of signals used by the threads library in *SET. */
5007 lin_thread_get_thread_signals (sigset_t
*set
)
5009 struct sigaction action
;
5010 int restart
, cancel
;
5012 sigemptyset (&blocked_mask
);
5015 restart
= get_signo ("__pthread_sig_restart");
5016 cancel
= get_signo ("__pthread_sig_cancel");
5018 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5019 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5020 not provide any way for the debugger to query the signal numbers -
5021 fortunately they don't change! */
5024 restart
= __SIGRTMIN
;
5027 cancel
= __SIGRTMIN
+ 1;
5029 sigaddset (set
, restart
);
5030 sigaddset (set
, cancel
);
5032 /* The GNU/Linux Threads library makes terminating threads send a
5033 special "cancel" signal instead of SIGCHLD. Make sure we catch
5034 those (to prevent them from terminating GDB itself, which is
5035 likely to be their default action) and treat them the same way as
5038 action
.sa_handler
= sigchld_handler
;
5039 sigemptyset (&action
.sa_mask
);
5040 action
.sa_flags
= SA_RESTART
;
5041 sigaction (cancel
, &action
, NULL
);
5043 /* We block the "cancel" signal throughout this code ... */
5044 sigaddset (&blocked_mask
, cancel
);
5045 sigprocmask (SIG_BLOCK
, &blocked_mask
, NULL
);
5047 /* ... except during a sigsuspend. */
5048 sigdelset (&suspend_mask
, cancel
);