1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2014 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "nat/linux-nat.h"
24 #include "nat/linux-waitpid.h"
27 #include "gdb_assert.h"
28 #ifdef HAVE_TKILL_SYSCALL
30 #include <sys/syscall.h>
32 #include <sys/ptrace.h>
33 #include "linux-nat.h"
34 #include "linux-ptrace.h"
35 #include "linux-procfs.h"
36 #include "linux-fork.h"
37 #include "gdbthread.h"
41 #include "inf-child.h"
42 #include "inf-ptrace.h"
44 #include <sys/procfs.h> /* for elf_gregset etc. */
45 #include "elf-bfd.h" /* for elfcore_write_* */
46 #include "gregset.h" /* for gregset */
47 #include "gdbcore.h" /* for get_exec_file */
48 #include <ctype.h> /* for isdigit */
49 #include <sys/stat.h> /* for struct stat */
50 #include <fcntl.h> /* for O_RDONLY */
52 #include "event-loop.h"
53 #include "event-top.h"
55 #include <sys/types.h>
57 #include "xml-support.h"
61 #include "linux-osdata.h"
62 #include "linux-tdep.h"
65 #include "tracepoint.h"
66 #include "exceptions.h"
68 #include "target-descriptions.h"
69 #include "filestuff.h"
73 #define SPUFS_MAGIC 0x23c9b64e
76 #ifdef HAVE_PERSONALITY
77 # include <sys/personality.h>
78 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
79 # define ADDR_NO_RANDOMIZE 0x0040000
81 #endif /* HAVE_PERSONALITY */
83 /* This comment documents high-level logic of this file.
85 Waiting for events in sync mode
86 ===============================
88 When waiting for an event in a specific thread, we just use waitpid, passing
89 the specific pid, and not passing WNOHANG.
91 When waiting for an event in all threads, waitpid is not quite good. Prior to
92 version 2.4, Linux can either wait for event in main thread, or in secondary
93 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
94 miss an event. The solution is to use non-blocking waitpid, together with
95 sigsuspend. First, we use non-blocking waitpid to get an event in the main
96 process, if any. Second, we use non-blocking waitpid with the __WCLONED
97 flag to check for events in cloned processes. If nothing is found, we use
98 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
99 happened to a child process -- and SIGCHLD will be delivered both for events
100 in main debugged process and in cloned processes. As soon as we know there's
101 an event, we get back to calling nonblocking waitpid with and without
104 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
105 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
106 blocked, the signal becomes pending and sigsuspend immediately
107 notices it and returns.
109 Waiting for events in async mode
110 ================================
112 In async mode, GDB should always be ready to handle both user input
113 and target events, so neither blocking waitpid nor sigsuspend are
114 viable options. Instead, we should asynchronously notify the GDB main
115 event loop whenever there's an unprocessed event from the target. We
116 detect asynchronous target events by handling SIGCHLD signals. To
117 notify the event loop about target events, the self-pipe trick is used
118 --- a pipe is registered as waitable event source in the event loop,
119 the event loop select/poll's on the read end of this pipe (as well on
120 other event sources, e.g., stdin), and the SIGCHLD handler writes a
121 byte to this pipe. This is more portable than relying on
122 pselect/ppoll, since on kernels that lack those syscalls, libc
123 emulates them with select/poll+sigprocmask, and that is racy
124 (a.k.a. plain broken).
126 Obviously, if we fail to notify the event loop if there's a target
127 event, it's bad. OTOH, if we notify the event loop when there's no
128 event from the target, linux_nat_wait will detect that there's no real
129 event to report, and return event of type TARGET_WAITKIND_IGNORE.
130 This is mostly harmless, but it will waste time and is better avoided.
132 The main design point is that every time GDB is outside linux-nat.c,
133 we have a SIGCHLD handler installed that is called when something
134 happens to the target and notifies the GDB event loop. Whenever GDB
135 core decides to handle the event, and calls into linux-nat.c, we
136 process things as in sync mode, except that the we never block in
139 While processing an event, we may end up momentarily blocked in
140 waitpid calls. Those waitpid calls, while blocking, are guarantied to
141 return quickly. E.g., in all-stop mode, before reporting to the core
142 that an LWP hit a breakpoint, all LWPs are stopped by sending them
143 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
144 Note that this is different from blocking indefinitely waiting for the
145 next event --- here, we're already handling an event.
150 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
151 signal is not entirely significant; we just need for a signal to be delivered,
152 so that we can intercept it. SIGSTOP's advantage is that it can not be
153 blocked. A disadvantage is that it is not a real-time signal, so it can only
154 be queued once; we do not keep track of other sources of SIGSTOP.
156 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
157 use them, because they have special behavior when the signal is generated -
158 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
159 kills the entire thread group.
161 A delivered SIGSTOP would stop the entire thread group, not just the thread we
162 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
163 cancel it (by PTRACE_CONT without passing SIGSTOP).
165 We could use a real-time signal instead. This would solve those problems; we
166 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
167 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
168 generates it, and there are races with trying to find a signal that is not
172 #define O_LARGEFILE 0
175 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
176 the use of the multi-threaded target. */
177 static struct target_ops
*linux_ops
;
178 static struct target_ops linux_ops_saved
;
180 /* The method to call, if any, when a new thread is attached. */
181 static void (*linux_nat_new_thread
) (struct lwp_info
*);
183 /* The method to call, if any, when a new fork is attached. */
184 static linux_nat_new_fork_ftype
*linux_nat_new_fork
;
186 /* The method to call, if any, when a process is no longer
188 static linux_nat_forget_process_ftype
*linux_nat_forget_process_hook
;
190 /* Hook to call prior to resuming a thread. */
191 static void (*linux_nat_prepare_to_resume
) (struct lwp_info
*);
193 /* The method to call, if any, when the siginfo object needs to be
194 converted between the layout returned by ptrace, and the layout in
195 the architecture of the inferior. */
196 static int (*linux_nat_siginfo_fixup
) (siginfo_t
*,
200 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
201 Called by our to_xfer_partial. */
202 static target_xfer_partial_ftype
*super_xfer_partial
;
204 /* The saved to_close method, inherited from inf-ptrace.c.
205 Called by our to_close. */
206 static void (*super_close
) (struct target_ops
*);
208 static unsigned int debug_linux_nat
;
210 show_debug_linux_nat (struct ui_file
*file
, int from_tty
,
211 struct cmd_list_element
*c
, const char *value
)
213 fprintf_filtered (file
, _("Debugging of GNU/Linux lwp module is %s.\n"),
217 struct simple_pid_list
221 struct simple_pid_list
*next
;
223 struct simple_pid_list
*stopped_pids
;
225 /* Async mode support. */
227 /* The read/write ends of the pipe registered as waitable file in the
229 static int linux_nat_event_pipe
[2] = { -1, -1 };
231 /* Flush the event pipe. */
234 async_file_flush (void)
241 ret
= read (linux_nat_event_pipe
[0], &buf
, 1);
243 while (ret
>= 0 || (ret
== -1 && errno
== EINTR
));
246 /* Put something (anything, doesn't matter what, or how much) in event
247 pipe, so that the select/poll in the event-loop realizes we have
248 something to process. */
251 async_file_mark (void)
255 /* It doesn't really matter what the pipe contains, as long we end
256 up with something in it. Might as well flush the previous
262 ret
= write (linux_nat_event_pipe
[1], "+", 1);
264 while (ret
== -1 && errno
== EINTR
);
266 /* Ignore EAGAIN. If the pipe is full, the event loop will already
267 be awakened anyway. */
270 static int kill_lwp (int lwpid
, int signo
);
272 static int stop_callback (struct lwp_info
*lp
, void *data
);
274 static void block_child_signals (sigset_t
*prev_mask
);
275 static void restore_child_signals_mask (sigset_t
*prev_mask
);
278 static struct lwp_info
*add_lwp (ptid_t ptid
);
279 static void purge_lwp_list (int pid
);
280 static void delete_lwp (ptid_t ptid
);
281 static struct lwp_info
*find_lwp_pid (ptid_t ptid
);
284 /* Trivial list manipulation functions to keep track of a list of
285 new stopped processes. */
287 add_to_pid_list (struct simple_pid_list
**listp
, int pid
, int status
)
289 struct simple_pid_list
*new_pid
= xmalloc (sizeof (struct simple_pid_list
));
292 new_pid
->status
= status
;
293 new_pid
->next
= *listp
;
298 in_pid_list_p (struct simple_pid_list
*list
, int pid
)
300 struct simple_pid_list
*p
;
302 for (p
= list
; p
!= NULL
; p
= p
->next
)
309 pull_pid_from_list (struct simple_pid_list
**listp
, int pid
, int *statusp
)
311 struct simple_pid_list
**p
;
313 for (p
= listp
; *p
!= NULL
; p
= &(*p
)->next
)
314 if ((*p
)->pid
== pid
)
316 struct simple_pid_list
*next
= (*p
)->next
;
318 *statusp
= (*p
)->status
;
326 /* Initialize ptrace warnings and check for supported ptrace
327 features given PID. */
330 linux_init_ptrace (pid_t pid
)
332 linux_enable_event_reporting (pid
);
333 linux_ptrace_init_warnings ();
337 linux_child_post_attach (struct target_ops
*self
, int pid
)
339 linux_init_ptrace (pid
);
343 linux_child_post_startup_inferior (struct target_ops
*self
, ptid_t ptid
)
345 linux_init_ptrace (ptid_get_pid (ptid
));
348 /* Return the number of known LWPs in the tgid given by PID. */
356 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
357 if (ptid_get_pid (lp
->ptid
) == pid
)
363 /* Call delete_lwp with prototype compatible for make_cleanup. */
366 delete_lwp_cleanup (void *lp_voidp
)
368 struct lwp_info
*lp
= lp_voidp
;
370 delete_lwp (lp
->ptid
);
374 linux_child_follow_fork (struct target_ops
*ops
, int follow_child
,
378 int parent_pid
, child_pid
;
380 has_vforked
= (inferior_thread ()->pending_follow
.kind
381 == TARGET_WAITKIND_VFORKED
);
382 parent_pid
= ptid_get_lwp (inferior_ptid
);
384 parent_pid
= ptid_get_pid (inferior_ptid
);
386 = ptid_get_pid (inferior_thread ()->pending_follow
.value
.related_pid
);
389 && !non_stop
/* Non-stop always resumes both branches. */
390 && (!target_is_async_p () || sync_execution
)
391 && !(follow_child
|| detach_fork
|| sched_multi
))
393 /* The parent stays blocked inside the vfork syscall until the
394 child execs or exits. If we don't let the child run, then
395 the parent stays blocked. If we're telling the parent to run
396 in the foreground, the user will not be able to ctrl-c to get
397 back the terminal, effectively hanging the debug session. */
398 fprintf_filtered (gdb_stderr
, _("\
399 Can not resume the parent process over vfork in the foreground while\n\
400 holding the child stopped. Try \"set detach-on-fork\" or \
401 \"set schedule-multiple\".\n"));
402 /* FIXME output string > 80 columns. */
408 struct lwp_info
*child_lp
= NULL
;
410 /* We're already attached to the parent, by default. */
412 /* Detach new forked process? */
415 struct cleanup
*old_chain
;
417 /* Before detaching from the child, remove all breakpoints
418 from it. If we forked, then this has already been taken
419 care of by infrun.c. If we vforked however, any
420 breakpoint inserted in the parent is visible in the
421 child, even those added while stopped in a vfork
422 catchpoint. This will remove the breakpoints from the
423 parent also, but they'll be reinserted below. */
426 /* keep breakpoints list in sync. */
427 remove_breakpoints_pid (ptid_get_pid (inferior_ptid
));
430 if (info_verbose
|| debug_linux_nat
)
432 target_terminal_ours ();
433 fprintf_filtered (gdb_stdlog
,
434 "Detaching after fork from "
435 "child process %d.\n",
439 old_chain
= save_inferior_ptid ();
440 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
442 child_lp
= add_lwp (inferior_ptid
);
443 child_lp
->stopped
= 1;
444 child_lp
->last_resume_kind
= resume_stop
;
445 make_cleanup (delete_lwp_cleanup
, child_lp
);
447 if (linux_nat_prepare_to_resume
!= NULL
)
448 linux_nat_prepare_to_resume (child_lp
);
449 ptrace (PTRACE_DETACH
, child_pid
, 0, 0);
451 do_cleanups (old_chain
);
455 struct inferior
*parent_inf
, *child_inf
;
456 struct cleanup
*old_chain
;
458 /* Add process to GDB's tables. */
459 child_inf
= add_inferior (child_pid
);
461 parent_inf
= current_inferior ();
462 child_inf
->attach_flag
= parent_inf
->attach_flag
;
463 copy_terminal_info (child_inf
, parent_inf
);
464 child_inf
->gdbarch
= parent_inf
->gdbarch
;
465 copy_inferior_target_desc_info (child_inf
, parent_inf
);
467 old_chain
= save_inferior_ptid ();
468 save_current_program_space ();
470 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
471 add_thread (inferior_ptid
);
472 child_lp
= add_lwp (inferior_ptid
);
473 child_lp
->stopped
= 1;
474 child_lp
->last_resume_kind
= resume_stop
;
475 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
477 /* If this is a vfork child, then the address-space is
478 shared with the parent. */
481 child_inf
->pspace
= parent_inf
->pspace
;
482 child_inf
->aspace
= parent_inf
->aspace
;
484 /* The parent will be frozen until the child is done
485 with the shared region. Keep track of the
487 child_inf
->vfork_parent
= parent_inf
;
488 child_inf
->pending_detach
= 0;
489 parent_inf
->vfork_child
= child_inf
;
490 parent_inf
->pending_detach
= 0;
494 child_inf
->aspace
= new_address_space ();
495 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
496 child_inf
->removable
= 1;
497 set_current_program_space (child_inf
->pspace
);
498 clone_program_space (child_inf
->pspace
, parent_inf
->pspace
);
500 /* Let the shared library layer (solib-svr4) learn about
501 this new process, relocate the cloned exec, pull in
502 shared libraries, and install the solib event
503 breakpoint. If a "cloned-VM" event was propagated
504 better throughout the core, this wouldn't be
506 solib_create_inferior_hook (0);
509 /* Let the thread_db layer learn about this new process. */
510 check_for_thread_db ();
512 do_cleanups (old_chain
);
517 struct lwp_info
*parent_lp
;
518 struct inferior
*parent_inf
;
520 parent_inf
= current_inferior ();
522 /* If we detached from the child, then we have to be careful
523 to not insert breakpoints in the parent until the child
524 is done with the shared memory region. However, if we're
525 staying attached to the child, then we can and should
526 insert breakpoints, so that we can debug it. A
527 subsequent child exec or exit is enough to know when does
528 the child stops using the parent's address space. */
529 parent_inf
->waiting_for_vfork_done
= detach_fork
;
530 parent_inf
->pspace
->breakpoints_not_allowed
= detach_fork
;
532 parent_lp
= find_lwp_pid (pid_to_ptid (parent_pid
));
533 gdb_assert (linux_supports_tracefork () >= 0);
535 if (linux_supports_tracevforkdone ())
538 fprintf_unfiltered (gdb_stdlog
,
539 "LCFF: waiting for VFORK_DONE on %d\n",
541 parent_lp
->stopped
= 1;
543 /* We'll handle the VFORK_DONE event like any other
544 event, in target_wait. */
548 /* We can't insert breakpoints until the child has
549 finished with the shared memory region. We need to
550 wait until that happens. Ideal would be to just
552 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
553 - waitpid (parent_pid, &status, __WALL);
554 However, most architectures can't handle a syscall
555 being traced on the way out if it wasn't traced on
558 We might also think to loop, continuing the child
559 until it exits or gets a SIGTRAP. One problem is
560 that the child might call ptrace with PTRACE_TRACEME.
562 There's no simple and reliable way to figure out when
563 the vforked child will be done with its copy of the
564 shared memory. We could step it out of the syscall,
565 two instructions, let it go, and then single-step the
566 parent once. When we have hardware single-step, this
567 would work; with software single-step it could still
568 be made to work but we'd have to be able to insert
569 single-step breakpoints in the child, and we'd have
570 to insert -just- the single-step breakpoint in the
571 parent. Very awkward.
573 In the end, the best we can do is to make sure it
574 runs for a little while. Hopefully it will be out of
575 range of any breakpoints we reinsert. Usually this
576 is only the single-step breakpoint at vfork's return
580 fprintf_unfiltered (gdb_stdlog
,
581 "LCFF: no VFORK_DONE "
582 "support, sleeping a bit\n");
586 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
587 and leave it pending. The next linux_nat_resume call
588 will notice a pending event, and bypasses actually
589 resuming the inferior. */
590 parent_lp
->status
= 0;
591 parent_lp
->waitstatus
.kind
= TARGET_WAITKIND_VFORK_DONE
;
592 parent_lp
->stopped
= 1;
594 /* If we're in async mode, need to tell the event loop
595 there's something here to process. */
596 if (target_can_async_p ())
603 struct inferior
*parent_inf
, *child_inf
;
604 struct lwp_info
*child_lp
;
605 struct program_space
*parent_pspace
;
607 if (info_verbose
|| debug_linux_nat
)
609 target_terminal_ours ();
611 fprintf_filtered (gdb_stdlog
,
612 _("Attaching after process %d "
613 "vfork to child process %d.\n"),
614 parent_pid
, child_pid
);
616 fprintf_filtered (gdb_stdlog
,
617 _("Attaching after process %d "
618 "fork to child process %d.\n"),
619 parent_pid
, child_pid
);
622 /* Add the new inferior first, so that the target_detach below
623 doesn't unpush the target. */
625 child_inf
= add_inferior (child_pid
);
627 parent_inf
= current_inferior ();
628 child_inf
->attach_flag
= parent_inf
->attach_flag
;
629 copy_terminal_info (child_inf
, parent_inf
);
630 child_inf
->gdbarch
= parent_inf
->gdbarch
;
631 copy_inferior_target_desc_info (child_inf
, parent_inf
);
633 parent_pspace
= parent_inf
->pspace
;
635 /* If we're vforking, we want to hold on to the parent until the
636 child exits or execs. At child exec or exit time we can
637 remove the old breakpoints from the parent and detach or
638 resume debugging it. Otherwise, detach the parent now; we'll
639 want to reuse it's program/address spaces, but we can't set
640 them to the child before removing breakpoints from the
641 parent, otherwise, the breakpoints module could decide to
642 remove breakpoints from the wrong process (since they'd be
643 assigned to the same address space). */
647 gdb_assert (child_inf
->vfork_parent
== NULL
);
648 gdb_assert (parent_inf
->vfork_child
== NULL
);
649 child_inf
->vfork_parent
= parent_inf
;
650 child_inf
->pending_detach
= 0;
651 parent_inf
->vfork_child
= child_inf
;
652 parent_inf
->pending_detach
= detach_fork
;
653 parent_inf
->waiting_for_vfork_done
= 0;
655 else if (detach_fork
)
656 target_detach (NULL
, 0);
658 /* Note that the detach above makes PARENT_INF dangling. */
660 /* Add the child thread to the appropriate lists, and switch to
661 this new thread, before cloning the program space, and
662 informing the solib layer about this new process. */
664 inferior_ptid
= ptid_build (child_pid
, child_pid
, 0);
665 add_thread (inferior_ptid
);
666 child_lp
= add_lwp (inferior_ptid
);
667 child_lp
->stopped
= 1;
668 child_lp
->last_resume_kind
= resume_stop
;
670 /* If this is a vfork child, then the address-space is shared
671 with the parent. If we detached from the parent, then we can
672 reuse the parent's program/address spaces. */
673 if (has_vforked
|| detach_fork
)
675 child_inf
->pspace
= parent_pspace
;
676 child_inf
->aspace
= child_inf
->pspace
->aspace
;
680 child_inf
->aspace
= new_address_space ();
681 child_inf
->pspace
= add_program_space (child_inf
->aspace
);
682 child_inf
->removable
= 1;
683 child_inf
->symfile_flags
= SYMFILE_NO_READ
;
684 set_current_program_space (child_inf
->pspace
);
685 clone_program_space (child_inf
->pspace
, parent_pspace
);
687 /* Let the shared library layer (solib-svr4) learn about
688 this new process, relocate the cloned exec, pull in
689 shared libraries, and install the solib event breakpoint.
690 If a "cloned-VM" event was propagated better throughout
691 the core, this wouldn't be required. */
692 solib_create_inferior_hook (0);
695 /* Let the thread_db layer learn about this new process. */
696 check_for_thread_db ();
704 linux_child_insert_fork_catchpoint (struct target_ops
*self
, int pid
)
706 return !linux_supports_tracefork ();
710 linux_child_remove_fork_catchpoint (struct target_ops
*self
, int pid
)
716 linux_child_insert_vfork_catchpoint (struct target_ops
*self
, int pid
)
718 return !linux_supports_tracefork ();
722 linux_child_remove_vfork_catchpoint (struct target_ops
*self
, int pid
)
728 linux_child_insert_exec_catchpoint (struct target_ops
*self
, int pid
)
730 return !linux_supports_tracefork ();
734 linux_child_remove_exec_catchpoint (struct target_ops
*self
, int pid
)
740 linux_child_set_syscall_catchpoint (struct target_ops
*self
,
741 int pid
, int needed
, int any_count
,
742 int table_size
, int *table
)
744 if (!linux_supports_tracesysgood ())
747 /* On GNU/Linux, we ignore the arguments. It means that we only
748 enable the syscall catchpoints, but do not disable them.
750 Also, we do not use the `table' information because we do not
751 filter system calls here. We let GDB do the logic for us. */
755 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
756 are processes sharing the same VM space. A multi-threaded process
757 is basically a group of such processes. However, such a grouping
758 is almost entirely a user-space issue; the kernel doesn't enforce
759 such a grouping at all (this might change in the future). In
760 general, we'll rely on the threads library (i.e. the GNU/Linux
761 Threads library) to provide such a grouping.
763 It is perfectly well possible to write a multi-threaded application
764 without the assistance of a threads library, by using the clone
765 system call directly. This module should be able to give some
766 rudimentary support for debugging such applications if developers
767 specify the CLONE_PTRACE flag in the clone system call, and are
768 using the Linux kernel 2.4 or above.
770 Note that there are some peculiarities in GNU/Linux that affect
773 - In general one should specify the __WCLONE flag to waitpid in
774 order to make it report events for any of the cloned processes
775 (and leave it out for the initial process). However, if a cloned
776 process has exited the exit status is only reported if the
777 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
778 we cannot use it since GDB must work on older systems too.
780 - When a traced, cloned process exits and is waited for by the
781 debugger, the kernel reassigns it to the original parent and
782 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
783 library doesn't notice this, which leads to the "zombie problem":
784 When debugged a multi-threaded process that spawns a lot of
785 threads will run out of processes, even if the threads exit,
786 because the "zombies" stay around. */
788 /* List of known LWPs. */
789 struct lwp_info
*lwp_list
;
792 /* Original signal mask. */
793 static sigset_t normal_mask
;
795 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
796 _initialize_linux_nat. */
797 static sigset_t suspend_mask
;
799 /* Signals to block to make that sigsuspend work. */
800 static sigset_t blocked_mask
;
802 /* SIGCHLD action. */
803 struct sigaction sigchld_action
;
805 /* Block child signals (SIGCHLD and linux threads signals), and store
806 the previous mask in PREV_MASK. */
809 block_child_signals (sigset_t
*prev_mask
)
811 /* Make sure SIGCHLD is blocked. */
812 if (!sigismember (&blocked_mask
, SIGCHLD
))
813 sigaddset (&blocked_mask
, SIGCHLD
);
815 sigprocmask (SIG_BLOCK
, &blocked_mask
, prev_mask
);
818 /* Restore child signals mask, previously returned by
819 block_child_signals. */
822 restore_child_signals_mask (sigset_t
*prev_mask
)
824 sigprocmask (SIG_SETMASK
, prev_mask
, NULL
);
827 /* Mask of signals to pass directly to the inferior. */
828 static sigset_t pass_mask
;
830 /* Update signals to pass to the inferior. */
832 linux_nat_pass_signals (struct target_ops
*self
,
833 int numsigs
, unsigned char *pass_signals
)
837 sigemptyset (&pass_mask
);
839 for (signo
= 1; signo
< NSIG
; signo
++)
841 int target_signo
= gdb_signal_from_host (signo
);
842 if (target_signo
< numsigs
&& pass_signals
[target_signo
])
843 sigaddset (&pass_mask
, signo
);
849 /* Prototypes for local functions. */
850 static int stop_wait_callback (struct lwp_info
*lp
, void *data
);
851 static int linux_thread_alive (ptid_t ptid
);
852 static char *linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
);
856 /* Destroy and free LP. */
859 lwp_free (struct lwp_info
*lp
)
861 xfree (lp
->arch_private
);
865 /* Remove all LWPs belong to PID from the lwp list. */
868 purge_lwp_list (int pid
)
870 struct lwp_info
*lp
, *lpprev
, *lpnext
;
874 for (lp
= lwp_list
; lp
; lp
= lpnext
)
878 if (ptid_get_pid (lp
->ptid
) == pid
)
883 lpprev
->next
= lp
->next
;
892 /* Add the LWP specified by PTID to the list. PTID is the first LWP
893 in the process. Return a pointer to the structure describing the
896 This differs from add_lwp in that we don't let the arch specific
897 bits know about this new thread. Current clients of this callback
898 take the opportunity to install watchpoints in the new thread, and
899 we shouldn't do that for the first thread. If we're spawning a
900 child ("run"), the thread executes the shell wrapper first, and we
901 shouldn't touch it until it execs the program we want to debug.
902 For "attach", it'd be okay to call the callback, but it's not
903 necessary, because watchpoints can't yet have been inserted into
906 static struct lwp_info
*
907 add_initial_lwp (ptid_t ptid
)
911 gdb_assert (ptid_lwp_p (ptid
));
913 lp
= (struct lwp_info
*) xmalloc (sizeof (struct lwp_info
));
915 memset (lp
, 0, sizeof (struct lwp_info
));
917 lp
->last_resume_kind
= resume_continue
;
918 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
929 /* Add the LWP specified by PID to the list. Return a pointer to the
930 structure describing the new LWP. The LWP should already be
933 static struct lwp_info
*
934 add_lwp (ptid_t ptid
)
938 lp
= add_initial_lwp (ptid
);
940 /* Let the arch specific bits know about this new thread. Current
941 clients of this callback take the opportunity to install
942 watchpoints in the new thread. We don't do this for the first
943 thread though. See add_initial_lwp. */
944 if (linux_nat_new_thread
!= NULL
)
945 linux_nat_new_thread (lp
);
950 /* Remove the LWP specified by PID from the list. */
953 delete_lwp (ptid_t ptid
)
955 struct lwp_info
*lp
, *lpprev
;
959 for (lp
= lwp_list
; lp
; lpprev
= lp
, lp
= lp
->next
)
960 if (ptid_equal (lp
->ptid
, ptid
))
967 lpprev
->next
= lp
->next
;
974 /* Return a pointer to the structure describing the LWP corresponding
975 to PID. If no corresponding LWP could be found, return NULL. */
977 static struct lwp_info
*
978 find_lwp_pid (ptid_t ptid
)
983 if (ptid_lwp_p (ptid
))
984 lwp
= ptid_get_lwp (ptid
);
986 lwp
= ptid_get_pid (ptid
);
988 for (lp
= lwp_list
; lp
; lp
= lp
->next
)
989 if (lwp
== ptid_get_lwp (lp
->ptid
))
995 /* Call CALLBACK with its second argument set to DATA for every LWP in
996 the list. If CALLBACK returns 1 for a particular LWP, return a
997 pointer to the structure describing that LWP immediately.
998 Otherwise return NULL. */
1001 iterate_over_lwps (ptid_t filter
,
1002 int (*callback
) (struct lwp_info
*, void *),
1005 struct lwp_info
*lp
, *lpnext
;
1007 for (lp
= lwp_list
; lp
; lp
= lpnext
)
1011 if (ptid_match (lp
->ptid
, filter
))
1013 if ((*callback
) (lp
, data
))
1021 /* Update our internal state when changing from one checkpoint to
1022 another indicated by NEW_PTID. We can only switch single-threaded
1023 applications, so we only create one new LWP, and the previous list
1027 linux_nat_switch_fork (ptid_t new_ptid
)
1029 struct lwp_info
*lp
;
1031 purge_lwp_list (ptid_get_pid (inferior_ptid
));
1033 lp
= add_lwp (new_ptid
);
1036 /* This changes the thread's ptid while preserving the gdb thread
1037 num. Also changes the inferior pid, while preserving the
1039 thread_change_ptid (inferior_ptid
, new_ptid
);
1041 /* We've just told GDB core that the thread changed target id, but,
1042 in fact, it really is a different thread, with different register
1044 registers_changed ();
1047 /* Handle the exit of a single thread LP. */
1050 exit_lwp (struct lwp_info
*lp
)
1052 struct thread_info
*th
= find_thread_ptid (lp
->ptid
);
1056 if (print_thread_events
)
1057 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp
->ptid
));
1059 delete_thread (lp
->ptid
);
1062 delete_lwp (lp
->ptid
);
1065 /* Wait for the LWP specified by LP, which we have just attached to.
1066 Returns a wait status for that LWP, to cache. */
1069 linux_nat_post_attach_wait (ptid_t ptid
, int first
, int *cloned
,
1072 pid_t new_pid
, pid
= ptid_get_lwp (ptid
);
1075 if (linux_proc_pid_is_stopped (pid
))
1077 if (debug_linux_nat
)
1078 fprintf_unfiltered (gdb_stdlog
,
1079 "LNPAW: Attaching to a stopped process\n");
1081 /* The process is definitely stopped. It is in a job control
1082 stop, unless the kernel predates the TASK_STOPPED /
1083 TASK_TRACED distinction, in which case it might be in a
1084 ptrace stop. Make sure it is in a ptrace stop; from there we
1085 can kill it, signal it, et cetera.
1087 First make sure there is a pending SIGSTOP. Since we are
1088 already attached, the process can not transition from stopped
1089 to running without a PTRACE_CONT; so we know this signal will
1090 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1091 probably already in the queue (unless this kernel is old
1092 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1093 is not an RT signal, it can only be queued once. */
1094 kill_lwp (pid
, SIGSTOP
);
1096 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1097 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1098 ptrace (PTRACE_CONT
, pid
, 0, 0);
1101 /* Make sure the initial process is stopped. The user-level threads
1102 layer might want to poke around in the inferior, and that won't
1103 work if things haven't stabilized yet. */
1104 new_pid
= my_waitpid (pid
, &status
, 0);
1105 if (new_pid
== -1 && errno
== ECHILD
)
1108 warning (_("%s is a cloned process"), target_pid_to_str (ptid
));
1110 /* Try again with __WCLONE to check cloned processes. */
1111 new_pid
= my_waitpid (pid
, &status
, __WCLONE
);
1115 gdb_assert (pid
== new_pid
);
1117 if (!WIFSTOPPED (status
))
1119 /* The pid we tried to attach has apparently just exited. */
1120 if (debug_linux_nat
)
1121 fprintf_unfiltered (gdb_stdlog
, "LNPAW: Failed to stop %d: %s",
1122 pid
, status_to_str (status
));
1126 if (WSTOPSIG (status
) != SIGSTOP
)
1129 if (debug_linux_nat
)
1130 fprintf_unfiltered (gdb_stdlog
,
1131 "LNPAW: Received %s after attaching\n",
1132 status_to_str (status
));
1138 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1139 the new LWP could not be attached, or 1 if we're already auto
1140 attached to this thread, but haven't processed the
1141 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1142 its existance, without considering it an error. */
1145 lin_lwp_attach_lwp (ptid_t ptid
)
1147 struct lwp_info
*lp
;
1150 gdb_assert (ptid_lwp_p (ptid
));
1152 lp
= find_lwp_pid (ptid
);
1153 lwpid
= ptid_get_lwp (ptid
);
1155 /* We assume that we're already attached to any LWP that has an id
1156 equal to the overall process id, and to any LWP that is already
1157 in our list of LWPs. If we're not seeing exit events from threads
1158 and we've had PID wraparound since we last tried to stop all threads,
1159 this assumption might be wrong; fortunately, this is very unlikely
1161 if (lwpid
!= ptid_get_pid (ptid
) && lp
== NULL
)
1163 int status
, cloned
= 0, signalled
= 0;
1165 if (ptrace (PTRACE_ATTACH
, lwpid
, 0, 0) < 0)
1167 if (linux_supports_tracefork ())
1169 /* If we haven't stopped all threads when we get here,
1170 we may have seen a thread listed in thread_db's list,
1171 but not processed the PTRACE_EVENT_CLONE yet. If
1172 that's the case, ignore this new thread, and let
1173 normal event handling discover it later. */
1174 if (in_pid_list_p (stopped_pids
, lwpid
))
1176 /* We've already seen this thread stop, but we
1177 haven't seen the PTRACE_EVENT_CLONE extended
1186 /* See if we've got a stop for this new child
1187 pending. If so, we're already attached. */
1188 new_pid
= my_waitpid (lwpid
, &status
, WNOHANG
);
1189 if (new_pid
== -1 && errno
== ECHILD
)
1190 new_pid
= my_waitpid (lwpid
, &status
, __WCLONE
| WNOHANG
);
1193 if (WIFSTOPPED (status
))
1194 add_to_pid_list (&stopped_pids
, lwpid
, status
);
1200 /* If we fail to attach to the thread, issue a warning,
1201 but continue. One way this can happen is if thread
1202 creation is interrupted; as of Linux kernel 2.6.19, a
1203 bug may place threads in the thread list and then fail
1205 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid
),
1206 safe_strerror (errno
));
1210 if (debug_linux_nat
)
1211 fprintf_unfiltered (gdb_stdlog
,
1212 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1213 target_pid_to_str (ptid
));
1215 status
= linux_nat_post_attach_wait (ptid
, 0, &cloned
, &signalled
);
1216 if (!WIFSTOPPED (status
))
1219 lp
= add_lwp (ptid
);
1221 lp
->cloned
= cloned
;
1222 lp
->signalled
= signalled
;
1223 if (WSTOPSIG (status
) != SIGSTOP
)
1226 lp
->status
= status
;
1229 target_post_attach (ptid_get_lwp (lp
->ptid
));
1231 if (debug_linux_nat
)
1233 fprintf_unfiltered (gdb_stdlog
,
1234 "LLAL: waitpid %s received %s\n",
1235 target_pid_to_str (ptid
),
1236 status_to_str (status
));
1241 /* We assume that the LWP representing the original process is
1242 already stopped. Mark it as stopped in the data structure
1243 that the GNU/linux ptrace layer uses to keep track of
1244 threads. Note that this won't have already been done since
1245 the main thread will have, we assume, been stopped by an
1246 attach from a different layer. */
1248 lp
= add_lwp (ptid
);
1252 lp
->last_resume_kind
= resume_stop
;
1257 linux_nat_create_inferior (struct target_ops
*ops
,
1258 char *exec_file
, char *allargs
, char **env
,
1261 #ifdef HAVE_PERSONALITY
1262 int personality_orig
= 0, personality_set
= 0;
1263 #endif /* HAVE_PERSONALITY */
1265 /* The fork_child mechanism is synchronous and calls target_wait, so
1266 we have to mask the async mode. */
1268 #ifdef HAVE_PERSONALITY
1269 if (disable_randomization
)
1272 personality_orig
= personality (0xffffffff);
1273 if (errno
== 0 && !(personality_orig
& ADDR_NO_RANDOMIZE
))
1275 personality_set
= 1;
1276 personality (personality_orig
| ADDR_NO_RANDOMIZE
);
1278 if (errno
!= 0 || (personality_set
1279 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE
)))
1280 warning (_("Error disabling address space randomization: %s"),
1281 safe_strerror (errno
));
1283 #endif /* HAVE_PERSONALITY */
1285 /* Make sure we report all signals during startup. */
1286 linux_nat_pass_signals (ops
, 0, NULL
);
1288 linux_ops
->to_create_inferior (ops
, exec_file
, allargs
, env
, from_tty
);
1290 #ifdef HAVE_PERSONALITY
1291 if (personality_set
)
1294 personality (personality_orig
);
1296 warning (_("Error restoring address space randomization: %s"),
1297 safe_strerror (errno
));
1299 #endif /* HAVE_PERSONALITY */
1303 linux_nat_attach (struct target_ops
*ops
, char *args
, int from_tty
)
1305 struct lwp_info
*lp
;
1308 volatile struct gdb_exception ex
;
1310 /* Make sure we report all signals during attach. */
1311 linux_nat_pass_signals (ops
, 0, NULL
);
1313 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
1315 linux_ops
->to_attach (ops
, args
, from_tty
);
1319 pid_t pid
= parse_pid_to_attach (args
);
1320 struct buffer buffer
;
1321 char *message
, *buffer_s
;
1323 message
= xstrdup (ex
.message
);
1324 make_cleanup (xfree
, message
);
1326 buffer_init (&buffer
);
1327 linux_ptrace_attach_fail_reason (pid
, &buffer
);
1329 buffer_grow_str0 (&buffer
, "");
1330 buffer_s
= buffer_finish (&buffer
);
1331 make_cleanup (xfree
, buffer_s
);
1333 if (*buffer_s
!= '\0')
1334 throw_error (ex
.error
, "warning: %s\n%s", buffer_s
, message
);
1336 throw_error (ex
.error
, "%s", message
);
1339 /* The ptrace base target adds the main thread with (pid,0,0)
1340 format. Decorate it with lwp info. */
1341 ptid
= ptid_build (ptid_get_pid (inferior_ptid
),
1342 ptid_get_pid (inferior_ptid
),
1344 thread_change_ptid (inferior_ptid
, ptid
);
1346 /* Add the initial process as the first LWP to the list. */
1347 lp
= add_initial_lwp (ptid
);
1349 status
= linux_nat_post_attach_wait (lp
->ptid
, 1, &lp
->cloned
,
1351 if (!WIFSTOPPED (status
))
1353 if (WIFEXITED (status
))
1355 int exit_code
= WEXITSTATUS (status
);
1357 target_terminal_ours ();
1358 target_mourn_inferior ();
1360 error (_("Unable to attach: program exited normally."));
1362 error (_("Unable to attach: program exited with code %d."),
1365 else if (WIFSIGNALED (status
))
1367 enum gdb_signal signo
;
1369 target_terminal_ours ();
1370 target_mourn_inferior ();
1372 signo
= gdb_signal_from_host (WTERMSIG (status
));
1373 error (_("Unable to attach: program terminated with signal "
1375 gdb_signal_to_name (signo
),
1376 gdb_signal_to_string (signo
));
1379 internal_error (__FILE__
, __LINE__
,
1380 _("unexpected status %d for PID %ld"),
1381 status
, (long) ptid_get_lwp (ptid
));
1386 /* Save the wait status to report later. */
1388 if (debug_linux_nat
)
1389 fprintf_unfiltered (gdb_stdlog
,
1390 "LNA: waitpid %ld, saving status %s\n",
1391 (long) ptid_get_pid (lp
->ptid
), status_to_str (status
));
1393 lp
->status
= status
;
1395 if (target_can_async_p ())
1396 target_async (inferior_event_handler
, 0);
1399 /* Get pending status of LP. */
1401 get_pending_status (struct lwp_info
*lp
, int *status
)
1403 enum gdb_signal signo
= GDB_SIGNAL_0
;
1405 /* If we paused threads momentarily, we may have stored pending
1406 events in lp->status or lp->waitstatus (see stop_wait_callback),
1407 and GDB core hasn't seen any signal for those threads.
1408 Otherwise, the last signal reported to the core is found in the
1409 thread object's stop_signal.
1411 There's a corner case that isn't handled here at present. Only
1412 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1413 stop_signal make sense as a real signal to pass to the inferior.
1414 Some catchpoint related events, like
1415 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1416 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1417 those traps are debug API (ptrace in our case) related and
1418 induced; the inferior wouldn't see them if it wasn't being
1419 traced. Hence, we should never pass them to the inferior, even
1420 when set to pass state. Since this corner case isn't handled by
1421 infrun.c when proceeding with a signal, for consistency, neither
1422 do we handle it here (or elsewhere in the file we check for
1423 signal pass state). Normally SIGTRAP isn't set to pass state, so
1424 this is really a corner case. */
1426 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1427 signo
= GDB_SIGNAL_0
; /* a pending ptrace event, not a real signal. */
1428 else if (lp
->status
)
1429 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1430 else if (non_stop
&& !is_executing (lp
->ptid
))
1432 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1434 signo
= tp
->suspend
.stop_signal
;
1438 struct target_waitstatus last
;
1441 get_last_target_status (&last_ptid
, &last
);
1443 if (ptid_get_lwp (lp
->ptid
) == ptid_get_lwp (last_ptid
))
1445 struct thread_info
*tp
= find_thread_ptid (lp
->ptid
);
1447 signo
= tp
->suspend
.stop_signal
;
1453 if (signo
== GDB_SIGNAL_0
)
1455 if (debug_linux_nat
)
1456 fprintf_unfiltered (gdb_stdlog
,
1457 "GPT: lwp %s has no pending signal\n",
1458 target_pid_to_str (lp
->ptid
));
1460 else if (!signal_pass_state (signo
))
1462 if (debug_linux_nat
)
1463 fprintf_unfiltered (gdb_stdlog
,
1464 "GPT: lwp %s had signal %s, "
1465 "but it is in no pass state\n",
1466 target_pid_to_str (lp
->ptid
),
1467 gdb_signal_to_string (signo
));
1471 *status
= W_STOPCODE (gdb_signal_to_host (signo
));
1473 if (debug_linux_nat
)
1474 fprintf_unfiltered (gdb_stdlog
,
1475 "GPT: lwp %s has pending signal %s\n",
1476 target_pid_to_str (lp
->ptid
),
1477 gdb_signal_to_string (signo
));
1484 detach_callback (struct lwp_info
*lp
, void *data
)
1486 gdb_assert (lp
->status
== 0 || WIFSTOPPED (lp
->status
));
1488 if (debug_linux_nat
&& lp
->status
)
1489 fprintf_unfiltered (gdb_stdlog
, "DC: Pending %s for %s on detach.\n",
1490 strsignal (WSTOPSIG (lp
->status
)),
1491 target_pid_to_str (lp
->ptid
));
1493 /* If there is a pending SIGSTOP, get rid of it. */
1496 if (debug_linux_nat
)
1497 fprintf_unfiltered (gdb_stdlog
,
1498 "DC: Sending SIGCONT to %s\n",
1499 target_pid_to_str (lp
->ptid
));
1501 kill_lwp (ptid_get_lwp (lp
->ptid
), SIGCONT
);
1505 /* We don't actually detach from the LWP that has an id equal to the
1506 overall process id just yet. */
1507 if (ptid_get_lwp (lp
->ptid
) != ptid_get_pid (lp
->ptid
))
1511 /* Pass on any pending signal for this LWP. */
1512 get_pending_status (lp
, &status
);
1514 if (linux_nat_prepare_to_resume
!= NULL
)
1515 linux_nat_prepare_to_resume (lp
);
1517 if (ptrace (PTRACE_DETACH
, ptid_get_lwp (lp
->ptid
), 0,
1518 WSTOPSIG (status
)) < 0)
1519 error (_("Can't detach %s: %s"), target_pid_to_str (lp
->ptid
),
1520 safe_strerror (errno
));
1522 if (debug_linux_nat
)
1523 fprintf_unfiltered (gdb_stdlog
,
1524 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1525 target_pid_to_str (lp
->ptid
),
1526 strsignal (WSTOPSIG (status
)));
1528 delete_lwp (lp
->ptid
);
1535 linux_nat_detach (struct target_ops
*ops
, const char *args
, int from_tty
)
1539 struct lwp_info
*main_lwp
;
1541 pid
= ptid_get_pid (inferior_ptid
);
1543 /* Don't unregister from the event loop, as there may be other
1544 inferiors running. */
1546 /* Stop all threads before detaching. ptrace requires that the
1547 thread is stopped to sucessfully detach. */
1548 iterate_over_lwps (pid_to_ptid (pid
), stop_callback
, NULL
);
1549 /* ... and wait until all of them have reported back that
1550 they're no longer running. */
1551 iterate_over_lwps (pid_to_ptid (pid
), stop_wait_callback
, NULL
);
1553 iterate_over_lwps (pid_to_ptid (pid
), detach_callback
, NULL
);
1555 /* Only the initial process should be left right now. */
1556 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid
)) == 1);
1558 main_lwp
= find_lwp_pid (pid_to_ptid (pid
));
1560 /* Pass on any pending signal for the last LWP. */
1561 if ((args
== NULL
|| *args
== '\0')
1562 && get_pending_status (main_lwp
, &status
) != -1
1563 && WIFSTOPPED (status
))
1567 /* Put the signal number in ARGS so that inf_ptrace_detach will
1568 pass it along with PTRACE_DETACH. */
1570 xsnprintf (tem
, 8, "%d", (int) WSTOPSIG (status
));
1572 if (debug_linux_nat
)
1573 fprintf_unfiltered (gdb_stdlog
,
1574 "LND: Sending signal %s to %s\n",
1576 target_pid_to_str (main_lwp
->ptid
));
1579 if (linux_nat_prepare_to_resume
!= NULL
)
1580 linux_nat_prepare_to_resume (main_lwp
);
1581 delete_lwp (main_lwp
->ptid
);
1583 if (forks_exist_p ())
1585 /* Multi-fork case. The current inferior_ptid is being detached
1586 from, but there are other viable forks to debug. Detach from
1587 the current fork, and context-switch to the first
1589 linux_fork_detach (args
, from_tty
);
1592 linux_ops
->to_detach (ops
, args
, from_tty
);
1598 resume_lwp (struct lwp_info
*lp
, int step
, enum gdb_signal signo
)
1602 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
1604 if (inf
->vfork_child
!= NULL
)
1606 if (debug_linux_nat
)
1607 fprintf_unfiltered (gdb_stdlog
,
1608 "RC: Not resuming %s (vfork parent)\n",
1609 target_pid_to_str (lp
->ptid
));
1611 else if (lp
->status
== 0
1612 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
1614 if (debug_linux_nat
)
1615 fprintf_unfiltered (gdb_stdlog
,
1616 "RC: Resuming sibling %s, %s, %s\n",
1617 target_pid_to_str (lp
->ptid
),
1618 (signo
!= GDB_SIGNAL_0
1619 ? strsignal (gdb_signal_to_host (signo
))
1621 step
? "step" : "resume");
1623 if (linux_nat_prepare_to_resume
!= NULL
)
1624 linux_nat_prepare_to_resume (lp
);
1625 linux_ops
->to_resume (linux_ops
,
1626 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
1630 lp
->stopped_by_watchpoint
= 0;
1634 if (debug_linux_nat
)
1635 fprintf_unfiltered (gdb_stdlog
,
1636 "RC: Not resuming sibling %s (has pending)\n",
1637 target_pid_to_str (lp
->ptid
));
1642 if (debug_linux_nat
)
1643 fprintf_unfiltered (gdb_stdlog
,
1644 "RC: Not resuming sibling %s (not stopped)\n",
1645 target_pid_to_str (lp
->ptid
));
1649 /* Resume LWP, with the last stop signal, if it is in pass state. */
1652 linux_nat_resume_callback (struct lwp_info
*lp
, void *data
)
1654 enum gdb_signal signo
= GDB_SIGNAL_0
;
1658 struct thread_info
*thread
;
1660 thread
= find_thread_ptid (lp
->ptid
);
1663 if (signal_pass_state (thread
->suspend
.stop_signal
))
1664 signo
= thread
->suspend
.stop_signal
;
1665 thread
->suspend
.stop_signal
= GDB_SIGNAL_0
;
1669 resume_lwp (lp
, 0, signo
);
1674 resume_clear_callback (struct lwp_info
*lp
, void *data
)
1677 lp
->last_resume_kind
= resume_stop
;
1682 resume_set_callback (struct lwp_info
*lp
, void *data
)
1685 lp
->last_resume_kind
= resume_continue
;
1690 linux_nat_resume (struct target_ops
*ops
,
1691 ptid_t ptid
, int step
, enum gdb_signal signo
)
1693 struct lwp_info
*lp
;
1696 if (debug_linux_nat
)
1697 fprintf_unfiltered (gdb_stdlog
,
1698 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1699 step
? "step" : "resume",
1700 target_pid_to_str (ptid
),
1701 (signo
!= GDB_SIGNAL_0
1702 ? strsignal (gdb_signal_to_host (signo
)) : "0"),
1703 target_pid_to_str (inferior_ptid
));
1705 /* A specific PTID means `step only this process id'. */
1706 resume_many
= (ptid_equal (minus_one_ptid
, ptid
)
1707 || ptid_is_pid (ptid
));
1709 /* Mark the lwps we're resuming as resumed. */
1710 iterate_over_lwps (ptid
, resume_set_callback
, NULL
);
1712 /* See if it's the current inferior that should be handled
1715 lp
= find_lwp_pid (inferior_ptid
);
1717 lp
= find_lwp_pid (ptid
);
1718 gdb_assert (lp
!= NULL
);
1720 /* Remember if we're stepping. */
1722 lp
->last_resume_kind
= step
? resume_step
: resume_continue
;
1724 /* If we have a pending wait status for this thread, there is no
1725 point in resuming the process. But first make sure that
1726 linux_nat_wait won't preemptively handle the event - we
1727 should never take this short-circuit if we are going to
1728 leave LP running, since we have skipped resuming all the
1729 other threads. This bit of code needs to be synchronized
1730 with linux_nat_wait. */
1732 if (lp
->status
&& WIFSTOPPED (lp
->status
))
1735 && WSTOPSIG (lp
->status
)
1736 && sigismember (&pass_mask
, WSTOPSIG (lp
->status
)))
1738 if (debug_linux_nat
)
1739 fprintf_unfiltered (gdb_stdlog
,
1740 "LLR: Not short circuiting for ignored "
1741 "status 0x%x\n", lp
->status
);
1743 /* FIXME: What should we do if we are supposed to continue
1744 this thread with a signal? */
1745 gdb_assert (signo
== GDB_SIGNAL_0
);
1746 signo
= gdb_signal_from_host (WSTOPSIG (lp
->status
));
1751 if (lp
->status
|| lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
1753 /* FIXME: What should we do if we are supposed to continue
1754 this thread with a signal? */
1755 gdb_assert (signo
== GDB_SIGNAL_0
);
1757 if (debug_linux_nat
)
1758 fprintf_unfiltered (gdb_stdlog
,
1759 "LLR: Short circuiting for status 0x%x\n",
1762 if (target_can_async_p ())
1764 target_async (inferior_event_handler
, 0);
1765 /* Tell the event loop we have something to process. */
1771 /* Mark LWP as not stopped to prevent it from being continued by
1772 linux_nat_resume_callback. */
1776 iterate_over_lwps (ptid
, linux_nat_resume_callback
, NULL
);
1778 /* Convert to something the lower layer understands. */
1779 ptid
= pid_to_ptid (ptid_get_lwp (lp
->ptid
));
1781 if (linux_nat_prepare_to_resume
!= NULL
)
1782 linux_nat_prepare_to_resume (lp
);
1783 linux_ops
->to_resume (linux_ops
, ptid
, step
, signo
);
1784 lp
->stopped_by_watchpoint
= 0;
1786 if (debug_linux_nat
)
1787 fprintf_unfiltered (gdb_stdlog
,
1788 "LLR: %s %s, %s (resume event thread)\n",
1789 step
? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1790 target_pid_to_str (ptid
),
1791 (signo
!= GDB_SIGNAL_0
1792 ? strsignal (gdb_signal_to_host (signo
)) : "0"));
1794 if (target_can_async_p ())
1795 target_async (inferior_event_handler
, 0);
1798 /* Send a signal to an LWP. */
1801 kill_lwp (int lwpid
, int signo
)
1803 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1804 fails, then we are not using nptl threads and we should be using kill. */
1806 #ifdef HAVE_TKILL_SYSCALL
1808 static int tkill_failed
;
1815 ret
= syscall (__NR_tkill
, lwpid
, signo
);
1816 if (errno
!= ENOSYS
)
1823 return kill (lwpid
, signo
);
1826 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1827 event, check if the core is interested in it: if not, ignore the
1828 event, and keep waiting; otherwise, we need to toggle the LWP's
1829 syscall entry/exit status, since the ptrace event itself doesn't
1830 indicate it, and report the trap to higher layers. */
1833 linux_handle_syscall_trap (struct lwp_info
*lp
, int stopping
)
1835 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1836 struct gdbarch
*gdbarch
= target_thread_architecture (lp
->ptid
);
1837 int syscall_number
= (int) gdbarch_get_syscall_number (gdbarch
, lp
->ptid
);
1841 /* If we're stopping threads, there's a SIGSTOP pending, which
1842 makes it so that the LWP reports an immediate syscall return,
1843 followed by the SIGSTOP. Skip seeing that "return" using
1844 PTRACE_CONT directly, and let stop_wait_callback collect the
1845 SIGSTOP. Later when the thread is resumed, a new syscall
1846 entry event. If we didn't do this (and returned 0), we'd
1847 leave a syscall entry pending, and our caller, by using
1848 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1849 itself. Later, when the user re-resumes this LWP, we'd see
1850 another syscall entry event and we'd mistake it for a return.
1852 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1853 (leaving immediately with LWP->signalled set, without issuing
1854 a PTRACE_CONT), it would still be problematic to leave this
1855 syscall enter pending, as later when the thread is resumed,
1856 it would then see the same syscall exit mentioned above,
1857 followed by the delayed SIGSTOP, while the syscall didn't
1858 actually get to execute. It seems it would be even more
1859 confusing to the user. */
1861 if (debug_linux_nat
)
1862 fprintf_unfiltered (gdb_stdlog
,
1863 "LHST: ignoring syscall %d "
1864 "for LWP %ld (stopping threads), "
1865 "resuming with PTRACE_CONT for SIGSTOP\n",
1867 ptid_get_lwp (lp
->ptid
));
1869 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1870 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
1874 if (catch_syscall_enabled ())
1876 /* Always update the entry/return state, even if this particular
1877 syscall isn't interesting to the core now. In async mode,
1878 the user could install a new catchpoint for this syscall
1879 between syscall enter/return, and we'll need to know to
1880 report a syscall return if that happens. */
1881 lp
->syscall_state
= (lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1882 ? TARGET_WAITKIND_SYSCALL_RETURN
1883 : TARGET_WAITKIND_SYSCALL_ENTRY
);
1885 if (catching_syscall_number (syscall_number
))
1887 /* Alright, an event to report. */
1888 ourstatus
->kind
= lp
->syscall_state
;
1889 ourstatus
->value
.syscall_number
= syscall_number
;
1891 if (debug_linux_nat
)
1892 fprintf_unfiltered (gdb_stdlog
,
1893 "LHST: stopping for %s of syscall %d"
1896 == TARGET_WAITKIND_SYSCALL_ENTRY
1897 ? "entry" : "return",
1899 ptid_get_lwp (lp
->ptid
));
1903 if (debug_linux_nat
)
1904 fprintf_unfiltered (gdb_stdlog
,
1905 "LHST: ignoring %s of syscall %d "
1907 lp
->syscall_state
== TARGET_WAITKIND_SYSCALL_ENTRY
1908 ? "entry" : "return",
1910 ptid_get_lwp (lp
->ptid
));
1914 /* If we had been syscall tracing, and hence used PT_SYSCALL
1915 before on this LWP, it could happen that the user removes all
1916 syscall catchpoints before we get to process this event.
1917 There are two noteworthy issues here:
1919 - When stopped at a syscall entry event, resuming with
1920 PT_STEP still resumes executing the syscall and reports a
1923 - Only PT_SYSCALL catches syscall enters. If we last
1924 single-stepped this thread, then this event can't be a
1925 syscall enter. If we last single-stepped this thread, this
1926 has to be a syscall exit.
1928 The points above mean that the next resume, be it PT_STEP or
1929 PT_CONTINUE, can not trigger a syscall trace event. */
1930 if (debug_linux_nat
)
1931 fprintf_unfiltered (gdb_stdlog
,
1932 "LHST: caught syscall event "
1933 "with no syscall catchpoints."
1934 " %d for LWP %ld, ignoring\n",
1936 ptid_get_lwp (lp
->ptid
));
1937 lp
->syscall_state
= TARGET_WAITKIND_IGNORE
;
1940 /* The core isn't interested in this event. For efficiency, avoid
1941 stopping all threads only to have the core resume them all again.
1942 Since we're not stopping threads, if we're still syscall tracing
1943 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1944 subsequent syscall. Simply resume using the inf-ptrace layer,
1945 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1947 /* Note that gdbarch_get_syscall_number may access registers, hence
1949 registers_changed ();
1950 if (linux_nat_prepare_to_resume
!= NULL
)
1951 linux_nat_prepare_to_resume (lp
);
1952 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
1953 lp
->step
, GDB_SIGNAL_0
);
1957 /* Handle a GNU/Linux extended wait response. If we see a clone
1958 event, we need to add the new LWP to our list (and not report the
1959 trap to higher layers). This function returns non-zero if the
1960 event should be ignored and we should wait again. If STOPPING is
1961 true, the new LWP remains stopped, otherwise it is continued. */
1964 linux_handle_extended_wait (struct lwp_info
*lp
, int status
,
1967 int pid
= ptid_get_lwp (lp
->ptid
);
1968 struct target_waitstatus
*ourstatus
= &lp
->waitstatus
;
1969 int event
= status
>> 16;
1971 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
1972 || event
== PTRACE_EVENT_CLONE
)
1974 unsigned long new_pid
;
1977 ptrace (PTRACE_GETEVENTMSG
, pid
, 0, &new_pid
);
1979 /* If we haven't already seen the new PID stop, wait for it now. */
1980 if (! pull_pid_from_list (&stopped_pids
, new_pid
, &status
))
1982 /* The new child has a pending SIGSTOP. We can't affect it until it
1983 hits the SIGSTOP, but we're already attached. */
1984 ret
= my_waitpid (new_pid
, &status
,
1985 (event
== PTRACE_EVENT_CLONE
) ? __WCLONE
: 0);
1987 perror_with_name (_("waiting for new child"));
1988 else if (ret
!= new_pid
)
1989 internal_error (__FILE__
, __LINE__
,
1990 _("wait returned unexpected PID %d"), ret
);
1991 else if (!WIFSTOPPED (status
))
1992 internal_error (__FILE__
, __LINE__
,
1993 _("wait returned unexpected status 0x%x"), status
);
1996 ourstatus
->value
.related_pid
= ptid_build (new_pid
, new_pid
, 0);
1998 if (event
== PTRACE_EVENT_FORK
|| event
== PTRACE_EVENT_VFORK
)
2000 /* The arch-specific native code may need to know about new
2001 forks even if those end up never mapped to an
2003 if (linux_nat_new_fork
!= NULL
)
2004 linux_nat_new_fork (lp
, new_pid
);
2007 if (event
== PTRACE_EVENT_FORK
2008 && linux_fork_checkpointing_p (ptid_get_pid (lp
->ptid
)))
2010 /* Handle checkpointing by linux-fork.c here as a special
2011 case. We don't want the follow-fork-mode or 'catch fork'
2012 to interfere with this. */
2014 /* This won't actually modify the breakpoint list, but will
2015 physically remove the breakpoints from the child. */
2016 detach_breakpoints (ptid_build (new_pid
, new_pid
, 0));
2018 /* Retain child fork in ptrace (stopped) state. */
2019 if (!find_fork_pid (new_pid
))
2022 /* Report as spurious, so that infrun doesn't want to follow
2023 this fork. We're actually doing an infcall in
2025 ourstatus
->kind
= TARGET_WAITKIND_SPURIOUS
;
2027 /* Report the stop to the core. */
2031 if (event
== PTRACE_EVENT_FORK
)
2032 ourstatus
->kind
= TARGET_WAITKIND_FORKED
;
2033 else if (event
== PTRACE_EVENT_VFORK
)
2034 ourstatus
->kind
= TARGET_WAITKIND_VFORKED
;
2037 struct lwp_info
*new_lp
;
2039 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
2041 if (debug_linux_nat
)
2042 fprintf_unfiltered (gdb_stdlog
,
2043 "LHEW: Got clone event "
2044 "from LWP %d, new child is LWP %ld\n",
2047 new_lp
= add_lwp (ptid_build (ptid_get_pid (lp
->ptid
), new_pid
, 0));
2049 new_lp
->stopped
= 1;
2051 if (WSTOPSIG (status
) != SIGSTOP
)
2053 /* This can happen if someone starts sending signals to
2054 the new thread before it gets a chance to run, which
2055 have a lower number than SIGSTOP (e.g. SIGUSR1).
2056 This is an unlikely case, and harder to handle for
2057 fork / vfork than for clone, so we do not try - but
2058 we handle it for clone events here. We'll send
2059 the other signal on to the thread below. */
2061 new_lp
->signalled
= 1;
2065 struct thread_info
*tp
;
2067 /* When we stop for an event in some other thread, and
2068 pull the thread list just as this thread has cloned,
2069 we'll have seen the new thread in the thread_db list
2070 before handling the CLONE event (glibc's
2071 pthread_create adds the new thread to the thread list
2072 before clone'ing, and has the kernel fill in the
2073 thread's tid on the clone call with
2074 CLONE_PARENT_SETTID). If that happened, and the core
2075 had requested the new thread to stop, we'll have
2076 killed it with SIGSTOP. But since SIGSTOP is not an
2077 RT signal, it can only be queued once. We need to be
2078 careful to not resume the LWP if we wanted it to
2079 stop. In that case, we'll leave the SIGSTOP pending.
2080 It will later be reported as GDB_SIGNAL_0. */
2081 tp
= find_thread_ptid (new_lp
->ptid
);
2082 if (tp
!= NULL
&& tp
->stop_requested
)
2083 new_lp
->last_resume_kind
= resume_stop
;
2090 /* Add the new thread to GDB's lists as soon as possible
2093 1) the frontend doesn't have to wait for a stop to
2096 2) we tag it with the correct running state. */
2098 /* If the thread_db layer is active, let it know about
2099 this new thread, and add it to GDB's list. */
2100 if (!thread_db_attach_lwp (new_lp
->ptid
))
2102 /* We're not using thread_db. Add it to GDB's
2104 target_post_attach (ptid_get_lwp (new_lp
->ptid
));
2105 add_thread (new_lp
->ptid
);
2110 set_running (new_lp
->ptid
, 1);
2111 set_executing (new_lp
->ptid
, 1);
2112 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2114 new_lp
->last_resume_kind
= resume_continue
;
2120 /* We created NEW_LP so it cannot yet contain STATUS. */
2121 gdb_assert (new_lp
->status
== 0);
2123 /* Save the wait status to report later. */
2124 if (debug_linux_nat
)
2125 fprintf_unfiltered (gdb_stdlog
,
2126 "LHEW: waitpid of new LWP %ld, "
2127 "saving status %s\n",
2128 (long) ptid_get_lwp (new_lp
->ptid
),
2129 status_to_str (status
));
2130 new_lp
->status
= status
;
2133 /* Note the need to use the low target ops to resume, to
2134 handle resuming with PT_SYSCALL if we have syscall
2138 new_lp
->resumed
= 1;
2142 gdb_assert (new_lp
->last_resume_kind
== resume_continue
);
2143 if (debug_linux_nat
)
2144 fprintf_unfiltered (gdb_stdlog
,
2145 "LHEW: resuming new LWP %ld\n",
2146 ptid_get_lwp (new_lp
->ptid
));
2147 if (linux_nat_prepare_to_resume
!= NULL
)
2148 linux_nat_prepare_to_resume (new_lp
);
2149 linux_ops
->to_resume (linux_ops
, pid_to_ptid (new_pid
),
2151 new_lp
->stopped
= 0;
2155 if (debug_linux_nat
)
2156 fprintf_unfiltered (gdb_stdlog
,
2157 "LHEW: resuming parent LWP %d\n", pid
);
2158 if (linux_nat_prepare_to_resume
!= NULL
)
2159 linux_nat_prepare_to_resume (lp
);
2160 linux_ops
->to_resume (linux_ops
,
2161 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
2170 if (event
== PTRACE_EVENT_EXEC
)
2172 if (debug_linux_nat
)
2173 fprintf_unfiltered (gdb_stdlog
,
2174 "LHEW: Got exec event from LWP %ld\n",
2175 ptid_get_lwp (lp
->ptid
));
2177 ourstatus
->kind
= TARGET_WAITKIND_EXECD
;
2178 ourstatus
->value
.execd_pathname
2179 = xstrdup (linux_child_pid_to_exec_file (NULL
, pid
));
2184 if (event
== PTRACE_EVENT_VFORK_DONE
)
2186 if (current_inferior ()->waiting_for_vfork_done
)
2188 if (debug_linux_nat
)
2189 fprintf_unfiltered (gdb_stdlog
,
2190 "LHEW: Got expected PTRACE_EVENT_"
2191 "VFORK_DONE from LWP %ld: stopping\n",
2192 ptid_get_lwp (lp
->ptid
));
2194 ourstatus
->kind
= TARGET_WAITKIND_VFORK_DONE
;
2198 if (debug_linux_nat
)
2199 fprintf_unfiltered (gdb_stdlog
,
2200 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2201 "from LWP %ld: resuming\n",
2202 ptid_get_lwp (lp
->ptid
));
2203 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2207 internal_error (__FILE__
, __LINE__
,
2208 _("unknown ptrace event %d"), event
);
2211 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2215 wait_lwp (struct lwp_info
*lp
)
2219 int thread_dead
= 0;
2222 gdb_assert (!lp
->stopped
);
2223 gdb_assert (lp
->status
== 0);
2225 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2226 block_child_signals (&prev_mask
);
2230 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2231 was right and we should just call sigsuspend. */
2233 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, WNOHANG
);
2234 if (pid
== -1 && errno
== ECHILD
)
2235 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), &status
, __WCLONE
| WNOHANG
);
2236 if (pid
== -1 && errno
== ECHILD
)
2238 /* The thread has previously exited. We need to delete it
2239 now because, for some vendor 2.4 kernels with NPTL
2240 support backported, there won't be an exit event unless
2241 it is the main thread. 2.6 kernels will report an exit
2242 event for each thread that exits, as expected. */
2244 if (debug_linux_nat
)
2245 fprintf_unfiltered (gdb_stdlog
, "WL: %s vanished.\n",
2246 target_pid_to_str (lp
->ptid
));
2251 /* Bugs 10970, 12702.
2252 Thread group leader may have exited in which case we'll lock up in
2253 waitpid if there are other threads, even if they are all zombies too.
2254 Basically, we're not supposed to use waitpid this way.
2255 __WCLONE is not applicable for the leader so we can't use that.
2256 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2257 process; it gets ESRCH both for the zombie and for running processes.
2259 As a workaround, check if we're waiting for the thread group leader and
2260 if it's a zombie, and avoid calling waitpid if it is.
2262 This is racy, what if the tgl becomes a zombie right after we check?
2263 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2264 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2266 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
)
2267 && linux_proc_pid_is_zombie (ptid_get_lwp (lp
->ptid
)))
2270 if (debug_linux_nat
)
2271 fprintf_unfiltered (gdb_stdlog
,
2272 "WL: Thread group leader %s vanished.\n",
2273 target_pid_to_str (lp
->ptid
));
2277 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2278 get invoked despite our caller had them intentionally blocked by
2279 block_child_signals. This is sensitive only to the loop of
2280 linux_nat_wait_1 and there if we get called my_waitpid gets called
2281 again before it gets to sigsuspend so we can safely let the handlers
2282 get executed here. */
2284 sigsuspend (&suspend_mask
);
2287 restore_child_signals_mask (&prev_mask
);
2291 gdb_assert (pid
== ptid_get_lwp (lp
->ptid
));
2293 if (debug_linux_nat
)
2295 fprintf_unfiltered (gdb_stdlog
,
2296 "WL: waitpid %s received %s\n",
2297 target_pid_to_str (lp
->ptid
),
2298 status_to_str (status
));
2301 /* Check if the thread has exited. */
2302 if (WIFEXITED (status
) || WIFSIGNALED (status
))
2305 if (debug_linux_nat
)
2306 fprintf_unfiltered (gdb_stdlog
, "WL: %s exited.\n",
2307 target_pid_to_str (lp
->ptid
));
2317 gdb_assert (WIFSTOPPED (status
));
2319 /* Handle GNU/Linux's syscall SIGTRAPs. */
2320 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2322 /* No longer need the sysgood bit. The ptrace event ends up
2323 recorded in lp->waitstatus if we care for it. We can carry
2324 on handling the event like a regular SIGTRAP from here
2326 status
= W_STOPCODE (SIGTRAP
);
2327 if (linux_handle_syscall_trap (lp
, 1))
2328 return wait_lwp (lp
);
2331 /* Handle GNU/Linux's extended waitstatus for trace events. */
2332 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2334 if (debug_linux_nat
)
2335 fprintf_unfiltered (gdb_stdlog
,
2336 "WL: Handling extended status 0x%06x\n",
2338 if (linux_handle_extended_wait (lp
, status
, 1))
2339 return wait_lwp (lp
);
2345 /* Send a SIGSTOP to LP. */
2348 stop_callback (struct lwp_info
*lp
, void *data
)
2350 if (!lp
->stopped
&& !lp
->signalled
)
2354 if (debug_linux_nat
)
2356 fprintf_unfiltered (gdb_stdlog
,
2357 "SC: kill %s **<SIGSTOP>**\n",
2358 target_pid_to_str (lp
->ptid
));
2361 ret
= kill_lwp (ptid_get_lwp (lp
->ptid
), SIGSTOP
);
2362 if (debug_linux_nat
)
2364 fprintf_unfiltered (gdb_stdlog
,
2365 "SC: lwp kill %d %s\n",
2367 errno
? safe_strerror (errno
) : "ERRNO-OK");
2371 gdb_assert (lp
->status
== 0);
2377 /* Request a stop on LWP. */
2380 linux_stop_lwp (struct lwp_info
*lwp
)
2382 stop_callback (lwp
, NULL
);
2385 /* Return non-zero if LWP PID has a pending SIGINT. */
2388 linux_nat_has_pending_sigint (int pid
)
2390 sigset_t pending
, blocked
, ignored
;
2392 linux_proc_pending_signals (pid
, &pending
, &blocked
, &ignored
);
2394 if (sigismember (&pending
, SIGINT
)
2395 && !sigismember (&ignored
, SIGINT
))
2401 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2404 set_ignore_sigint (struct lwp_info
*lp
, void *data
)
2406 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2407 flag to consume the next one. */
2408 if (lp
->stopped
&& lp
->status
!= 0 && WIFSTOPPED (lp
->status
)
2409 && WSTOPSIG (lp
->status
) == SIGINT
)
2412 lp
->ignore_sigint
= 1;
2417 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2418 This function is called after we know the LWP has stopped; if the LWP
2419 stopped before the expected SIGINT was delivered, then it will never have
2420 arrived. Also, if the signal was delivered to a shared queue and consumed
2421 by a different thread, it will never be delivered to this LWP. */
2424 maybe_clear_ignore_sigint (struct lwp_info
*lp
)
2426 if (!lp
->ignore_sigint
)
2429 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp
->ptid
)))
2431 if (debug_linux_nat
)
2432 fprintf_unfiltered (gdb_stdlog
,
2433 "MCIS: Clearing bogus flag for %s\n",
2434 target_pid_to_str (lp
->ptid
));
2435 lp
->ignore_sigint
= 0;
2439 /* Fetch the possible triggered data watchpoint info and store it in
2442 On some archs, like x86, that use debug registers to set
2443 watchpoints, it's possible that the way to know which watched
2444 address trapped, is to check the register that is used to select
2445 which address to watch. Problem is, between setting the watchpoint
2446 and reading back which data address trapped, the user may change
2447 the set of watchpoints, and, as a consequence, GDB changes the
2448 debug registers in the inferior. To avoid reading back a stale
2449 stopped-data-address when that happens, we cache in LP the fact
2450 that a watchpoint trapped, and the corresponding data address, as
2451 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2452 registers meanwhile, we have the cached data we can rely on. */
2455 save_sigtrap (struct lwp_info
*lp
)
2457 struct cleanup
*old_chain
;
2459 if (linux_ops
->to_stopped_by_watchpoint
== NULL
)
2461 lp
->stopped_by_watchpoint
= 0;
2465 old_chain
= save_inferior_ptid ();
2466 inferior_ptid
= lp
->ptid
;
2468 lp
->stopped_by_watchpoint
= linux_ops
->to_stopped_by_watchpoint (linux_ops
);
2470 if (lp
->stopped_by_watchpoint
)
2472 if (linux_ops
->to_stopped_data_address
!= NULL
)
2473 lp
->stopped_data_address_p
=
2474 linux_ops
->to_stopped_data_address (¤t_target
,
2475 &lp
->stopped_data_address
);
2477 lp
->stopped_data_address_p
= 0;
2480 do_cleanups (old_chain
);
2483 /* See save_sigtrap. */
2486 linux_nat_stopped_by_watchpoint (struct target_ops
*ops
)
2488 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2490 gdb_assert (lp
!= NULL
);
2492 return lp
->stopped_by_watchpoint
;
2496 linux_nat_stopped_data_address (struct target_ops
*ops
, CORE_ADDR
*addr_p
)
2498 struct lwp_info
*lp
= find_lwp_pid (inferior_ptid
);
2500 gdb_assert (lp
!= NULL
);
2502 *addr_p
= lp
->stopped_data_address
;
2504 return lp
->stopped_data_address_p
;
2507 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2510 sigtrap_is_event (int status
)
2512 return WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
;
2515 /* SIGTRAP-like events recognizer. */
2517 static int (*linux_nat_status_is_event
) (int status
) = sigtrap_is_event
;
2519 /* Check for SIGTRAP-like events in LP. */
2522 linux_nat_lp_status_is_event (struct lwp_info
*lp
)
2524 /* We check for lp->waitstatus in addition to lp->status, because we can
2525 have pending process exits recorded in lp->status
2526 and W_EXITCODE(0,0) == 0. We should probably have an additional
2527 lp->status_p flag. */
2529 return (lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
2530 && linux_nat_status_is_event (lp
->status
));
2533 /* Set alternative SIGTRAP-like events recognizer. If
2534 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2538 linux_nat_set_status_is_event (struct target_ops
*t
,
2539 int (*status_is_event
) (int status
))
2541 linux_nat_status_is_event
= status_is_event
;
2544 /* Wait until LP is stopped. */
2547 stop_wait_callback (struct lwp_info
*lp
, void *data
)
2549 struct inferior
*inf
= find_inferior_pid (ptid_get_pid (lp
->ptid
));
2551 /* If this is a vfork parent, bail out, it is not going to report
2552 any SIGSTOP until the vfork is done with. */
2553 if (inf
->vfork_child
!= NULL
)
2560 status
= wait_lwp (lp
);
2564 if (lp
->ignore_sigint
&& WIFSTOPPED (status
)
2565 && WSTOPSIG (status
) == SIGINT
)
2567 lp
->ignore_sigint
= 0;
2570 ptrace (PTRACE_CONT
, ptid_get_lwp (lp
->ptid
), 0, 0);
2571 if (debug_linux_nat
)
2572 fprintf_unfiltered (gdb_stdlog
,
2573 "PTRACE_CONT %s, 0, 0 (%s) "
2574 "(discarding SIGINT)\n",
2575 target_pid_to_str (lp
->ptid
),
2576 errno
? safe_strerror (errno
) : "OK");
2578 return stop_wait_callback (lp
, NULL
);
2581 maybe_clear_ignore_sigint (lp
);
2583 if (WSTOPSIG (status
) != SIGSTOP
)
2585 /* The thread was stopped with a signal other than SIGSTOP. */
2589 if (debug_linux_nat
)
2590 fprintf_unfiltered (gdb_stdlog
,
2591 "SWC: Pending event %s in %s\n",
2592 status_to_str ((int) status
),
2593 target_pid_to_str (lp
->ptid
));
2595 /* Save the sigtrap event. */
2596 lp
->status
= status
;
2597 gdb_assert (!lp
->stopped
);
2598 gdb_assert (lp
->signalled
);
2603 /* We caught the SIGSTOP that we intended to catch, so
2604 there's no SIGSTOP pending. */
2606 if (debug_linux_nat
)
2607 fprintf_unfiltered (gdb_stdlog
,
2608 "SWC: Delayed SIGSTOP caught for %s.\n",
2609 target_pid_to_str (lp
->ptid
));
2613 /* Reset SIGNALLED only after the stop_wait_callback call
2614 above as it does gdb_assert on SIGNALLED. */
2622 /* Return non-zero if LP has a wait status pending. */
2625 status_callback (struct lwp_info
*lp
, void *data
)
2627 /* Only report a pending wait status if we pretend that this has
2628 indeed been resumed. */
2632 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2634 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2635 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2636 0', so a clean process exit can not be stored pending in
2637 lp->status, it is indistinguishable from
2638 no-pending-status. */
2642 if (lp
->status
!= 0)
2648 /* Return non-zero if LP isn't stopped. */
2651 running_callback (struct lwp_info
*lp
, void *data
)
2653 return (!lp
->stopped
2654 || ((lp
->status
!= 0
2655 || lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
2659 /* Count the LWP's that have had events. */
2662 count_events_callback (struct lwp_info
*lp
, void *data
)
2666 gdb_assert (count
!= NULL
);
2668 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2669 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2675 /* Select the LWP (if any) that is currently being single-stepped. */
2678 select_singlestep_lwp_callback (struct lwp_info
*lp
, void *data
)
2680 if (lp
->last_resume_kind
== resume_step
2687 /* Select the Nth LWP that has had a SIGTRAP event. */
2690 select_event_lwp_callback (struct lwp_info
*lp
, void *data
)
2692 int *selector
= data
;
2694 gdb_assert (selector
!= NULL
);
2696 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2697 if (lp
->resumed
&& linux_nat_lp_status_is_event (lp
))
2698 if ((*selector
)-- == 0)
2705 cancel_breakpoint (struct lwp_info
*lp
)
2707 /* Arrange for a breakpoint to be hit again later. We don't keep
2708 the SIGTRAP status and don't forward the SIGTRAP signal to the
2709 LWP. We will handle the current event, eventually we will resume
2710 this LWP, and this breakpoint will trap again.
2712 If we do not do this, then we run the risk that the user will
2713 delete or disable the breakpoint, but the LWP will have already
2716 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
2717 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
2720 pc
= regcache_read_pc (regcache
) - target_decr_pc_after_break (gdbarch
);
2721 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
2723 if (debug_linux_nat
)
2724 fprintf_unfiltered (gdb_stdlog
,
2725 "CB: Push back breakpoint for %s\n",
2726 target_pid_to_str (lp
->ptid
));
2728 /* Back up the PC if necessary. */
2729 if (target_decr_pc_after_break (gdbarch
))
2730 regcache_write_pc (regcache
, pc
);
2738 cancel_breakpoints_callback (struct lwp_info
*lp
, void *data
)
2740 struct lwp_info
*event_lp
= data
;
2742 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2746 /* If a LWP other than the LWP that we're reporting an event for has
2747 hit a GDB breakpoint (as opposed to some random trap signal),
2748 then just arrange for it to hit it again later. We don't keep
2749 the SIGTRAP status and don't forward the SIGTRAP signal to the
2750 LWP. We will handle the current event, eventually we will resume
2751 all LWPs, and this one will get its breakpoint trap again.
2753 If we do not do this, then we run the risk that the user will
2754 delete or disable the breakpoint, but the LWP will have already
2757 if (linux_nat_lp_status_is_event (lp
)
2758 && cancel_breakpoint (lp
))
2759 /* Throw away the SIGTRAP. */
2765 /* Select one LWP out of those that have events pending. */
2768 select_event_lwp (ptid_t filter
, struct lwp_info
**orig_lp
, int *status
)
2771 int random_selector
;
2772 struct lwp_info
*event_lp
;
2774 /* Record the wait status for the original LWP. */
2775 (*orig_lp
)->status
= *status
;
2777 /* Give preference to any LWP that is being single-stepped. */
2778 event_lp
= iterate_over_lwps (filter
,
2779 select_singlestep_lwp_callback
, NULL
);
2780 if (event_lp
!= NULL
)
2782 if (debug_linux_nat
)
2783 fprintf_unfiltered (gdb_stdlog
,
2784 "SEL: Select single-step %s\n",
2785 target_pid_to_str (event_lp
->ptid
));
2789 /* No single-stepping LWP. Select one at random, out of those
2790 which have had SIGTRAP events. */
2792 /* First see how many SIGTRAP events we have. */
2793 iterate_over_lwps (filter
, count_events_callback
, &num_events
);
2795 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2796 random_selector
= (int)
2797 ((num_events
* (double) rand ()) / (RAND_MAX
+ 1.0));
2799 if (debug_linux_nat
&& num_events
> 1)
2800 fprintf_unfiltered (gdb_stdlog
,
2801 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2802 num_events
, random_selector
);
2804 event_lp
= iterate_over_lwps (filter
,
2805 select_event_lwp_callback
,
2809 if (event_lp
!= NULL
)
2811 /* Switch the event LWP. */
2812 *orig_lp
= event_lp
;
2813 *status
= event_lp
->status
;
2816 /* Flush the wait status for the event LWP. */
2817 (*orig_lp
)->status
= 0;
2820 /* Return non-zero if LP has been resumed. */
2823 resumed_callback (struct lwp_info
*lp
, void *data
)
2828 /* Stop an active thread, verify it still exists, then resume it. If
2829 the thread ends up with a pending status, then it is not resumed,
2830 and *DATA (really a pointer to int), is set. */
2833 stop_and_resume_callback (struct lwp_info
*lp
, void *data
)
2835 int *new_pending_p
= data
;
2839 ptid_t ptid
= lp
->ptid
;
2841 stop_callback (lp
, NULL
);
2842 stop_wait_callback (lp
, NULL
);
2844 /* Resume if the lwp still exists, and the core wanted it
2846 lp
= find_lwp_pid (ptid
);
2849 if (lp
->last_resume_kind
== resume_stop
2852 /* The core wanted the LWP to stop. Even if it stopped
2853 cleanly (with SIGSTOP), leave the event pending. */
2854 if (debug_linux_nat
)
2855 fprintf_unfiltered (gdb_stdlog
,
2856 "SARC: core wanted LWP %ld stopped "
2857 "(leaving SIGSTOP pending)\n",
2858 ptid_get_lwp (lp
->ptid
));
2859 lp
->status
= W_STOPCODE (SIGSTOP
);
2862 if (lp
->status
== 0)
2864 if (debug_linux_nat
)
2865 fprintf_unfiltered (gdb_stdlog
,
2866 "SARC: re-resuming LWP %ld\n",
2867 ptid_get_lwp (lp
->ptid
));
2868 resume_lwp (lp
, lp
->step
, GDB_SIGNAL_0
);
2872 if (debug_linux_nat
)
2873 fprintf_unfiltered (gdb_stdlog
,
2874 "SARC: not re-resuming LWP %ld "
2876 ptid_get_lwp (lp
->ptid
));
2885 /* Check if we should go on and pass this event to common code.
2886 Return the affected lwp if we are, or NULL otherwise. If we stop
2887 all lwps temporarily, we may end up with new pending events in some
2888 other lwp. In that case set *NEW_PENDING_P to true. */
2890 static struct lwp_info
*
2891 linux_nat_filter_event (int lwpid
, int status
, int *new_pending_p
)
2893 struct lwp_info
*lp
;
2897 lp
= find_lwp_pid (pid_to_ptid (lwpid
));
2899 /* Check for stop events reported by a process we didn't already
2900 know about - anything not already in our LWP list.
2902 If we're expecting to receive stopped processes after
2903 fork, vfork, and clone events, then we'll just add the
2904 new one to our list and go back to waiting for the event
2905 to be reported - the stopped process might be returned
2906 from waitpid before or after the event is.
2908 But note the case of a non-leader thread exec'ing after the
2909 leader having exited, and gone from our lists. The non-leader
2910 thread changes its tid to the tgid. */
2912 if (WIFSTOPPED (status
) && lp
== NULL
2913 && (WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 == PTRACE_EVENT_EXEC
))
2915 /* A multi-thread exec after we had seen the leader exiting. */
2916 if (debug_linux_nat
)
2917 fprintf_unfiltered (gdb_stdlog
,
2918 "LLW: Re-adding thread group leader LWP %d.\n",
2921 lp
= add_lwp (ptid_build (lwpid
, lwpid
, 0));
2924 add_thread (lp
->ptid
);
2927 if (WIFSTOPPED (status
) && !lp
)
2929 add_to_pid_list (&stopped_pids
, lwpid
, status
);
2933 /* Make sure we don't report an event for the exit of an LWP not in
2934 our list, i.e. not part of the current process. This can happen
2935 if we detach from a program we originally forked and then it
2937 if (!WIFSTOPPED (status
) && !lp
)
2940 /* Handle GNU/Linux's syscall SIGTRAPs. */
2941 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SYSCALL_SIGTRAP
)
2943 /* No longer need the sysgood bit. The ptrace event ends up
2944 recorded in lp->waitstatus if we care for it. We can carry
2945 on handling the event like a regular SIGTRAP from here
2947 status
= W_STOPCODE (SIGTRAP
);
2948 if (linux_handle_syscall_trap (lp
, 0))
2952 /* Handle GNU/Linux's extended waitstatus for trace events. */
2953 if (WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGTRAP
&& status
>> 16 != 0)
2955 if (debug_linux_nat
)
2956 fprintf_unfiltered (gdb_stdlog
,
2957 "LLW: Handling extended status 0x%06x\n",
2959 if (linux_handle_extended_wait (lp
, status
, 0))
2963 if (linux_nat_status_is_event (status
))
2966 /* Check if the thread has exited. */
2967 if ((WIFEXITED (status
) || WIFSIGNALED (status
))
2968 && num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
2970 /* If this is the main thread, we must stop all threads and verify
2971 if they are still alive. This is because in the nptl thread model
2972 on Linux 2.4, there is no signal issued for exiting LWPs
2973 other than the main thread. We only get the main thread exit
2974 signal once all child threads have already exited. If we
2975 stop all the threads and use the stop_wait_callback to check
2976 if they have exited we can determine whether this signal
2977 should be ignored or whether it means the end of the debugged
2978 application, regardless of which threading model is being
2980 if (ptid_get_pid (lp
->ptid
) == ptid_get_lwp (lp
->ptid
))
2983 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp
->ptid
)),
2984 stop_and_resume_callback
, new_pending_p
);
2987 if (debug_linux_nat
)
2988 fprintf_unfiltered (gdb_stdlog
,
2989 "LLW: %s exited.\n",
2990 target_pid_to_str (lp
->ptid
));
2992 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1)
2994 /* If there is at least one more LWP, then the exit signal
2995 was not the end of the debugged application and should be
3002 /* Check if the current LWP has previously exited. In the nptl
3003 thread model, LWPs other than the main thread do not issue
3004 signals when they exit so we must check whenever the thread has
3005 stopped. A similar check is made in stop_wait_callback(). */
3006 if (num_lwps (ptid_get_pid (lp
->ptid
)) > 1 && !linux_thread_alive (lp
->ptid
))
3008 ptid_t ptid
= pid_to_ptid (ptid_get_pid (lp
->ptid
));
3010 if (debug_linux_nat
)
3011 fprintf_unfiltered (gdb_stdlog
,
3012 "LLW: %s exited.\n",
3013 target_pid_to_str (lp
->ptid
));
3017 /* Make sure there is at least one thread running. */
3018 gdb_assert (iterate_over_lwps (ptid
, running_callback
, NULL
));
3020 /* Discard the event. */
3024 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3025 an attempt to stop an LWP. */
3027 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGSTOP
)
3029 if (debug_linux_nat
)
3030 fprintf_unfiltered (gdb_stdlog
,
3031 "LLW: Delayed SIGSTOP caught for %s.\n",
3032 target_pid_to_str (lp
->ptid
));
3036 if (lp
->last_resume_kind
!= resume_stop
)
3038 /* This is a delayed SIGSTOP. */
3040 registers_changed ();
3042 if (linux_nat_prepare_to_resume
!= NULL
)
3043 linux_nat_prepare_to_resume (lp
);
3044 linux_ops
->to_resume (linux_ops
,
3045 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3046 lp
->step
, GDB_SIGNAL_0
);
3047 if (debug_linux_nat
)
3048 fprintf_unfiltered (gdb_stdlog
,
3049 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3051 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3052 target_pid_to_str (lp
->ptid
));
3055 gdb_assert (lp
->resumed
);
3057 /* Discard the event. */
3062 /* Make sure we don't report a SIGINT that we have already displayed
3063 for another thread. */
3064 if (lp
->ignore_sigint
3065 && WIFSTOPPED (status
) && WSTOPSIG (status
) == SIGINT
)
3067 if (debug_linux_nat
)
3068 fprintf_unfiltered (gdb_stdlog
,
3069 "LLW: Delayed SIGINT caught for %s.\n",
3070 target_pid_to_str (lp
->ptid
));
3072 /* This is a delayed SIGINT. */
3073 lp
->ignore_sigint
= 0;
3075 registers_changed ();
3076 if (linux_nat_prepare_to_resume
!= NULL
)
3077 linux_nat_prepare_to_resume (lp
);
3078 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3079 lp
->step
, GDB_SIGNAL_0
);
3080 if (debug_linux_nat
)
3081 fprintf_unfiltered (gdb_stdlog
,
3082 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3084 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3085 target_pid_to_str (lp
->ptid
));
3088 gdb_assert (lp
->resumed
);
3090 /* Discard the event. */
3094 /* An interesting event. */
3096 lp
->status
= status
;
3100 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3101 their exits until all other threads in the group have exited. */
3104 check_zombie_leaders (void)
3106 struct inferior
*inf
;
3110 struct lwp_info
*leader_lp
;
3115 leader_lp
= find_lwp_pid (pid_to_ptid (inf
->pid
));
3116 if (leader_lp
!= NULL
3117 /* Check if there are other threads in the group, as we may
3118 have raced with the inferior simply exiting. */
3119 && num_lwps (inf
->pid
) > 1
3120 && linux_proc_pid_is_zombie (inf
->pid
))
3122 if (debug_linux_nat
)
3123 fprintf_unfiltered (gdb_stdlog
,
3124 "CZL: Thread group leader %d zombie "
3125 "(it exited, or another thread execd).\n",
3128 /* A leader zombie can mean one of two things:
3130 - It exited, and there's an exit status pending
3131 available, or only the leader exited (not the whole
3132 program). In the latter case, we can't waitpid the
3133 leader's exit status until all other threads are gone.
3135 - There are 3 or more threads in the group, and a thread
3136 other than the leader exec'd. On an exec, the Linux
3137 kernel destroys all other threads (except the execing
3138 one) in the thread group, and resets the execing thread's
3139 tid to the tgid. No exit notification is sent for the
3140 execing thread -- from the ptracer's perspective, it
3141 appears as though the execing thread just vanishes.
3142 Until we reap all other threads except the leader and the
3143 execing thread, the leader will be zombie, and the
3144 execing thread will be in `D (disc sleep)'. As soon as
3145 all other threads are reaped, the execing thread changes
3146 it's tid to the tgid, and the previous (zombie) leader
3147 vanishes, giving place to the "new" leader. We could try
3148 distinguishing the exit and exec cases, by waiting once
3149 more, and seeing if something comes out, but it doesn't
3150 sound useful. The previous leader _does_ go away, and
3151 we'll re-add the new one once we see the exec event
3152 (which is just the same as what would happen if the
3153 previous leader did exit voluntarily before some other
3156 if (debug_linux_nat
)
3157 fprintf_unfiltered (gdb_stdlog
,
3158 "CZL: Thread group leader %d vanished.\n",
3160 exit_lwp (leader_lp
);
3166 linux_nat_wait_1 (struct target_ops
*ops
,
3167 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3170 static sigset_t prev_mask
;
3171 enum resume_kind last_resume_kind
;
3172 struct lwp_info
*lp
;
3175 if (debug_linux_nat
)
3176 fprintf_unfiltered (gdb_stdlog
, "LLW: enter\n");
3178 /* The first time we get here after starting a new inferior, we may
3179 not have added it to the LWP list yet - this is the earliest
3180 moment at which we know its PID. */
3181 if (ptid_is_pid (inferior_ptid
))
3183 /* Upgrade the main thread's ptid. */
3184 thread_change_ptid (inferior_ptid
,
3185 ptid_build (ptid_get_pid (inferior_ptid
),
3186 ptid_get_pid (inferior_ptid
), 0));
3188 lp
= add_initial_lwp (inferior_ptid
);
3192 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3193 block_child_signals (&prev_mask
);
3199 /* First check if there is a LWP with a wait status pending. */
3200 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3202 /* Any LWP in the PTID group that's been resumed will do. */
3203 lp
= iterate_over_lwps (ptid
, status_callback
, NULL
);
3206 if (debug_linux_nat
&& lp
->status
)
3207 fprintf_unfiltered (gdb_stdlog
,
3208 "LLW: Using pending wait status %s for %s.\n",
3209 status_to_str (lp
->status
),
3210 target_pid_to_str (lp
->ptid
));
3213 else if (ptid_lwp_p (ptid
))
3215 if (debug_linux_nat
)
3216 fprintf_unfiltered (gdb_stdlog
,
3217 "LLW: Waiting for specific LWP %s.\n",
3218 target_pid_to_str (ptid
));
3220 /* We have a specific LWP to check. */
3221 lp
= find_lwp_pid (ptid
);
3224 if (debug_linux_nat
&& lp
->status
)
3225 fprintf_unfiltered (gdb_stdlog
,
3226 "LLW: Using pending wait status %s for %s.\n",
3227 status_to_str (lp
->status
),
3228 target_pid_to_str (lp
->ptid
));
3230 /* We check for lp->waitstatus in addition to lp->status,
3231 because we can have pending process exits recorded in
3232 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3233 an additional lp->status_p flag. */
3234 if (lp
->status
== 0 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3238 if (!target_can_async_p ())
3240 /* Causes SIGINT to be passed on to the attached process. */
3244 /* But if we don't find a pending event, we'll have to wait. */
3250 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3253 - If the thread group leader exits while other threads in the
3254 thread group still exist, waitpid(TGID, ...) hangs. That
3255 waitpid won't return an exit status until the other threads
3256 in the group are reapped.
3258 - When a non-leader thread execs, that thread just vanishes
3259 without reporting an exit (so we'd hang if we waited for it
3260 explicitly in that case). The exec event is reported to
3264 lwpid
= my_waitpid (-1, &status
, __WCLONE
| WNOHANG
);
3265 if (lwpid
== 0 || (lwpid
== -1 && errno
== ECHILD
))
3266 lwpid
= my_waitpid (-1, &status
, WNOHANG
);
3268 if (debug_linux_nat
)
3269 fprintf_unfiltered (gdb_stdlog
,
3270 "LNW: waitpid(-1, ...) returned %d, %s\n",
3271 lwpid
, errno
? safe_strerror (errno
) : "ERRNO-OK");
3275 /* If this is true, then we paused LWPs momentarily, and may
3276 now have pending events to handle. */
3279 if (debug_linux_nat
)
3281 fprintf_unfiltered (gdb_stdlog
,
3282 "LLW: waitpid %ld received %s\n",
3283 (long) lwpid
, status_to_str (status
));
3286 lp
= linux_nat_filter_event (lwpid
, status
, &new_pending
);
3288 /* STATUS is now no longer valid, use LP->STATUS instead. */
3291 if (lp
&& !ptid_match (lp
->ptid
, ptid
))
3293 gdb_assert (lp
->resumed
);
3295 if (debug_linux_nat
)
3297 "LWP %ld got an event %06x, leaving pending.\n",
3298 ptid_get_lwp (lp
->ptid
), lp
->status
);
3300 if (WIFSTOPPED (lp
->status
))
3302 if (WSTOPSIG (lp
->status
) != SIGSTOP
)
3304 /* Cancel breakpoint hits. The breakpoint may
3305 be removed before we fetch events from this
3306 process to report to the core. It is best
3307 not to assume the moribund breakpoints
3308 heuristic always handles these cases --- it
3309 could be too many events go through to the
3310 core before this one is handled. All-stop
3311 always cancels breakpoint hits in all
3314 && linux_nat_lp_status_is_event (lp
)
3315 && cancel_breakpoint (lp
))
3317 /* Throw away the SIGTRAP. */
3320 if (debug_linux_nat
)
3322 "LLW: LWP %ld hit a breakpoint while"
3323 " waiting for another process;"
3325 ptid_get_lwp (lp
->ptid
));
3335 else if (WIFEXITED (lp
->status
) || WIFSIGNALED (lp
->status
))
3337 if (debug_linux_nat
)
3339 "Process %ld exited while stopping LWPs\n",
3340 ptid_get_lwp (lp
->ptid
));
3342 /* This was the last lwp in the process. Since
3343 events are serialized to GDB core, and we can't
3344 report this one right now, but GDB core and the
3345 other target layers will want to be notified
3346 about the exit code/signal, leave the status
3347 pending for the next time we're able to report
3350 /* Prevent trying to stop this thread again. We'll
3351 never try to resume it because it has a pending
3355 /* Dead LWP's aren't expected to reported a pending
3359 /* Store the pending event in the waitstatus as
3360 well, because W_EXITCODE(0,0) == 0. */
3361 store_waitstatus (&lp
->waitstatus
, lp
->status
);
3370 /* Some LWP now has a pending event. Go all the way
3371 back to check it. */
3377 /* We got an event to report to the core. */
3381 /* Retry until nothing comes out of waitpid. A single
3382 SIGCHLD can indicate more than one child stopped. */
3386 /* Check for zombie thread group leaders. Those can't be reaped
3387 until all other threads in the thread group are. */
3388 check_zombie_leaders ();
3390 /* If there are no resumed children left, bail. We'd be stuck
3391 forever in the sigsuspend call below otherwise. */
3392 if (iterate_over_lwps (ptid
, resumed_callback
, NULL
) == NULL
)
3394 if (debug_linux_nat
)
3395 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (no resumed LWP)\n");
3397 ourstatus
->kind
= TARGET_WAITKIND_NO_RESUMED
;
3399 if (!target_can_async_p ())
3400 clear_sigint_trap ();
3402 restore_child_signals_mask (&prev_mask
);
3403 return minus_one_ptid
;
3406 /* No interesting event to report to the core. */
3408 if (target_options
& TARGET_WNOHANG
)
3410 if (debug_linux_nat
)
3411 fprintf_unfiltered (gdb_stdlog
, "LLW: exit (ignore)\n");
3413 ourstatus
->kind
= TARGET_WAITKIND_IGNORE
;
3414 restore_child_signals_mask (&prev_mask
);
3415 return minus_one_ptid
;
3418 /* We shouldn't end up here unless we want to try again. */
3419 gdb_assert (lp
== NULL
);
3421 /* Block until we get an event reported with SIGCHLD. */
3422 sigsuspend (&suspend_mask
);
3425 if (!target_can_async_p ())
3426 clear_sigint_trap ();
3430 status
= lp
->status
;
3433 /* Don't report signals that GDB isn't interested in, such as
3434 signals that are neither printed nor stopped upon. Stopping all
3435 threads can be a bit time-consuming so if we want decent
3436 performance with heavily multi-threaded programs, especially when
3437 they're using a high frequency timer, we'd better avoid it if we
3440 if (WIFSTOPPED (status
))
3442 enum gdb_signal signo
= gdb_signal_from_host (WSTOPSIG (status
));
3444 /* When using hardware single-step, we need to report every signal.
3445 Otherwise, signals in pass_mask may be short-circuited. */
3447 && WSTOPSIG (status
) && sigismember (&pass_mask
, WSTOPSIG (status
)))
3449 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3450 here? It is not clear we should. GDB may not expect
3451 other threads to run. On the other hand, not resuming
3452 newly attached threads may cause an unwanted delay in
3453 getting them running. */
3454 registers_changed ();
3455 if (linux_nat_prepare_to_resume
!= NULL
)
3456 linux_nat_prepare_to_resume (lp
);
3457 linux_ops
->to_resume (linux_ops
,
3458 pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3460 if (debug_linux_nat
)
3461 fprintf_unfiltered (gdb_stdlog
,
3462 "LLW: %s %s, %s (preempt 'handle')\n",
3464 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3465 target_pid_to_str (lp
->ptid
),
3466 (signo
!= GDB_SIGNAL_0
3467 ? strsignal (gdb_signal_to_host (signo
))
3475 /* Only do the below in all-stop, as we currently use SIGINT
3476 to implement target_stop (see linux_nat_stop) in
3478 if (signo
== GDB_SIGNAL_INT
&& signal_pass_state (signo
) == 0)
3480 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3481 forwarded to the entire process group, that is, all LWPs
3482 will receive it - unless they're using CLONE_THREAD to
3483 share signals. Since we only want to report it once, we
3484 mark it as ignored for all LWPs except this one. */
3485 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid
)),
3486 set_ignore_sigint
, NULL
);
3487 lp
->ignore_sigint
= 0;
3490 maybe_clear_ignore_sigint (lp
);
3494 /* This LWP is stopped now. */
3497 if (debug_linux_nat
)
3498 fprintf_unfiltered (gdb_stdlog
, "LLW: Candidate event %s in %s.\n",
3499 status_to_str (status
), target_pid_to_str (lp
->ptid
));
3503 /* Now stop all other LWP's ... */
3504 iterate_over_lwps (minus_one_ptid
, stop_callback
, NULL
);
3506 /* ... and wait until all of them have reported back that
3507 they're no longer running. */
3508 iterate_over_lwps (minus_one_ptid
, stop_wait_callback
, NULL
);
3510 /* If we're not waiting for a specific LWP, choose an event LWP
3511 from among those that have had events. Giving equal priority
3512 to all LWPs that have had events helps prevent
3514 if (ptid_equal (ptid
, minus_one_ptid
) || ptid_is_pid (ptid
))
3515 select_event_lwp (ptid
, &lp
, &status
);
3517 /* Now that we've selected our final event LWP, cancel any
3518 breakpoints in other LWPs that have hit a GDB breakpoint.
3519 See the comment in cancel_breakpoints_callback to find out
3521 iterate_over_lwps (minus_one_ptid
, cancel_breakpoints_callback
, lp
);
3523 /* We'll need this to determine whether to report a SIGSTOP as
3524 TARGET_WAITKIND_0. Need to take a copy because
3525 resume_clear_callback clears it. */
3526 last_resume_kind
= lp
->last_resume_kind
;
3528 /* In all-stop, from the core's perspective, all LWPs are now
3529 stopped until a new resume action is sent over. */
3530 iterate_over_lwps (minus_one_ptid
, resume_clear_callback
, NULL
);
3535 last_resume_kind
= lp
->last_resume_kind
;
3536 resume_clear_callback (lp
, NULL
);
3539 if (linux_nat_status_is_event (status
))
3541 if (debug_linux_nat
)
3542 fprintf_unfiltered (gdb_stdlog
,
3543 "LLW: trap ptid is %s.\n",
3544 target_pid_to_str (lp
->ptid
));
3547 if (lp
->waitstatus
.kind
!= TARGET_WAITKIND_IGNORE
)
3549 *ourstatus
= lp
->waitstatus
;
3550 lp
->waitstatus
.kind
= TARGET_WAITKIND_IGNORE
;
3553 store_waitstatus (ourstatus
, status
);
3555 if (debug_linux_nat
)
3556 fprintf_unfiltered (gdb_stdlog
, "LLW: exit\n");
3558 restore_child_signals_mask (&prev_mask
);
3560 if (last_resume_kind
== resume_stop
3561 && ourstatus
->kind
== TARGET_WAITKIND_STOPPED
3562 && WSTOPSIG (status
) == SIGSTOP
)
3564 /* A thread that has been requested to stop by GDB with
3565 target_stop, and it stopped cleanly, so report as SIG0. The
3566 use of SIGSTOP is an implementation detail. */
3567 ourstatus
->value
.sig
= GDB_SIGNAL_0
;
3570 if (ourstatus
->kind
== TARGET_WAITKIND_EXITED
3571 || ourstatus
->kind
== TARGET_WAITKIND_SIGNALLED
)
3574 lp
->core
= linux_common_core_of_thread (lp
->ptid
);
3579 /* Resume LWPs that are currently stopped without any pending status
3580 to report, but are resumed from the core's perspective. */
3583 resume_stopped_resumed_lwps (struct lwp_info
*lp
, void *data
)
3585 ptid_t
*wait_ptid_p
= data
;
3590 && lp
->waitstatus
.kind
== TARGET_WAITKIND_IGNORE
)
3592 struct regcache
*regcache
= get_thread_regcache (lp
->ptid
);
3593 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
3594 CORE_ADDR pc
= regcache_read_pc (regcache
);
3596 gdb_assert (is_executing (lp
->ptid
));
3598 /* Don't bother if there's a breakpoint at PC that we'd hit
3599 immediately, and we're not waiting for this LWP. */
3600 if (!ptid_match (lp
->ptid
, *wait_ptid_p
))
3602 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache
), pc
))
3606 if (debug_linux_nat
)
3607 fprintf_unfiltered (gdb_stdlog
,
3608 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3609 target_pid_to_str (lp
->ptid
),
3610 paddress (gdbarch
, pc
),
3613 registers_changed ();
3614 if (linux_nat_prepare_to_resume
!= NULL
)
3615 linux_nat_prepare_to_resume (lp
);
3616 linux_ops
->to_resume (linux_ops
, pid_to_ptid (ptid_get_lwp (lp
->ptid
)),
3617 lp
->step
, GDB_SIGNAL_0
);
3619 lp
->stopped_by_watchpoint
= 0;
3626 linux_nat_wait (struct target_ops
*ops
,
3627 ptid_t ptid
, struct target_waitstatus
*ourstatus
,
3632 if (debug_linux_nat
)
3634 char *options_string
;
3636 options_string
= target_options_to_string (target_options
);
3637 fprintf_unfiltered (gdb_stdlog
,
3638 "linux_nat_wait: [%s], [%s]\n",
3639 target_pid_to_str (ptid
),
3641 xfree (options_string
);
3644 /* Flush the async file first. */
3645 if (target_can_async_p ())
3646 async_file_flush ();
3648 /* Resume LWPs that are currently stopped without any pending status
3649 to report, but are resumed from the core's perspective. LWPs get
3650 in this state if we find them stopping at a time we're not
3651 interested in reporting the event (target_wait on a
3652 specific_process, for example, see linux_nat_wait_1), and
3653 meanwhile the event became uninteresting. Don't bother resuming
3654 LWPs we're not going to wait for if they'd stop immediately. */
3656 iterate_over_lwps (minus_one_ptid
, resume_stopped_resumed_lwps
, &ptid
);
3658 event_ptid
= linux_nat_wait_1 (ops
, ptid
, ourstatus
, target_options
);
3660 /* If we requested any event, and something came out, assume there
3661 may be more. If we requested a specific lwp or process, also
3662 assume there may be more. */
3663 if (target_can_async_p ()
3664 && ((ourstatus
->kind
!= TARGET_WAITKIND_IGNORE
3665 && ourstatus
->kind
!= TARGET_WAITKIND_NO_RESUMED
)
3666 || !ptid_equal (ptid
, minus_one_ptid
)))
3669 /* Get ready for the next event. */
3670 if (target_can_async_p ())
3671 target_async (inferior_event_handler
, 0);
3677 kill_callback (struct lwp_info
*lp
, void *data
)
3679 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3682 kill (ptid_get_lwp (lp
->ptid
), SIGKILL
);
3683 if (debug_linux_nat
)
3684 fprintf_unfiltered (gdb_stdlog
,
3685 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3686 target_pid_to_str (lp
->ptid
),
3687 errno
? safe_strerror (errno
) : "OK");
3689 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3692 ptrace (PTRACE_KILL
, ptid_get_lwp (lp
->ptid
), 0, 0);
3693 if (debug_linux_nat
)
3694 fprintf_unfiltered (gdb_stdlog
,
3695 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3696 target_pid_to_str (lp
->ptid
),
3697 errno
? safe_strerror (errno
) : "OK");
3703 kill_wait_callback (struct lwp_info
*lp
, void *data
)
3707 /* We must make sure that there are no pending events (delayed
3708 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3709 program doesn't interfere with any following debugging session. */
3711 /* For cloned processes we must check both with __WCLONE and
3712 without, since the exit status of a cloned process isn't reported
3718 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, __WCLONE
);
3719 if (pid
!= (pid_t
) -1)
3721 if (debug_linux_nat
)
3722 fprintf_unfiltered (gdb_stdlog
,
3723 "KWC: wait %s received unknown.\n",
3724 target_pid_to_str (lp
->ptid
));
3725 /* The Linux kernel sometimes fails to kill a thread
3726 completely after PTRACE_KILL; that goes from the stop
3727 point in do_fork out to the one in
3728 get_signal_to_deliever and waits again. So kill it
3730 kill_callback (lp
, NULL
);
3733 while (pid
== ptid_get_lwp (lp
->ptid
));
3735 gdb_assert (pid
== -1 && errno
== ECHILD
);
3740 pid
= my_waitpid (ptid_get_lwp (lp
->ptid
), NULL
, 0);
3741 if (pid
!= (pid_t
) -1)
3743 if (debug_linux_nat
)
3744 fprintf_unfiltered (gdb_stdlog
,
3745 "KWC: wait %s received unk.\n",
3746 target_pid_to_str (lp
->ptid
));
3747 /* See the call to kill_callback above. */
3748 kill_callback (lp
, NULL
);
3751 while (pid
== ptid_get_lwp (lp
->ptid
));
3753 gdb_assert (pid
== -1 && errno
== ECHILD
);
3758 linux_nat_kill (struct target_ops
*ops
)
3760 struct target_waitstatus last
;
3764 /* If we're stopped while forking and we haven't followed yet,
3765 kill the other task. We need to do this first because the
3766 parent will be sleeping if this is a vfork. */
3768 get_last_target_status (&last_ptid
, &last
);
3770 if (last
.kind
== TARGET_WAITKIND_FORKED
3771 || last
.kind
== TARGET_WAITKIND_VFORKED
)
3773 ptrace (PT_KILL
, ptid_get_pid (last
.value
.related_pid
), 0, 0);
3776 /* Let the arch-specific native code know this process is
3778 linux_nat_forget_process (ptid_get_pid (last
.value
.related_pid
));
3781 if (forks_exist_p ())
3782 linux_fork_killall ();
3785 ptid_t ptid
= pid_to_ptid (ptid_get_pid (inferior_ptid
));
3787 /* Stop all threads before killing them, since ptrace requires
3788 that the thread is stopped to sucessfully PTRACE_KILL. */
3789 iterate_over_lwps (ptid
, stop_callback
, NULL
);
3790 /* ... and wait until all of them have reported back that
3791 they're no longer running. */
3792 iterate_over_lwps (ptid
, stop_wait_callback
, NULL
);
3794 /* Kill all LWP's ... */
3795 iterate_over_lwps (ptid
, kill_callback
, NULL
);
3797 /* ... and wait until we've flushed all events. */
3798 iterate_over_lwps (ptid
, kill_wait_callback
, NULL
);
3801 target_mourn_inferior ();
3805 linux_nat_mourn_inferior (struct target_ops
*ops
)
3807 int pid
= ptid_get_pid (inferior_ptid
);
3809 purge_lwp_list (pid
);
3811 if (! forks_exist_p ())
3812 /* Normal case, no other forks available. */
3813 linux_ops
->to_mourn_inferior (ops
);
3815 /* Multi-fork case. The current inferior_ptid has exited, but
3816 there are other viable forks to debug. Delete the exiting
3817 one and context-switch to the first available. */
3818 linux_fork_mourn_inferior ();
3820 /* Let the arch-specific native code know this process is gone. */
3821 linux_nat_forget_process (pid
);
3824 /* Convert a native/host siginfo object, into/from the siginfo in the
3825 layout of the inferiors' architecture. */
3828 siginfo_fixup (siginfo_t
*siginfo
, gdb_byte
*inf_siginfo
, int direction
)
3832 if (linux_nat_siginfo_fixup
!= NULL
)
3833 done
= linux_nat_siginfo_fixup (siginfo
, inf_siginfo
, direction
);
3835 /* If there was no callback, or the callback didn't do anything,
3836 then just do a straight memcpy. */
3840 memcpy (siginfo
, inf_siginfo
, sizeof (siginfo_t
));
3842 memcpy (inf_siginfo
, siginfo
, sizeof (siginfo_t
));
3846 static enum target_xfer_status
3847 linux_xfer_siginfo (struct target_ops
*ops
, enum target_object object
,
3848 const char *annex
, gdb_byte
*readbuf
,
3849 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
3850 ULONGEST
*xfered_len
)
3854 gdb_byte inf_siginfo
[sizeof (siginfo_t
)];
3856 gdb_assert (object
== TARGET_OBJECT_SIGNAL_INFO
);
3857 gdb_assert (readbuf
|| writebuf
);
3859 pid
= ptid_get_lwp (inferior_ptid
);
3861 pid
= ptid_get_pid (inferior_ptid
);
3863 if (offset
> sizeof (siginfo
))
3864 return TARGET_XFER_E_IO
;
3867 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3869 return TARGET_XFER_E_IO
;
3871 /* When GDB is built as a 64-bit application, ptrace writes into
3872 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3873 inferior with a 64-bit GDB should look the same as debugging it
3874 with a 32-bit GDB, we need to convert it. GDB core always sees
3875 the converted layout, so any read/write will have to be done
3877 siginfo_fixup (&siginfo
, inf_siginfo
, 0);
3879 if (offset
+ len
> sizeof (siginfo
))
3880 len
= sizeof (siginfo
) - offset
;
3882 if (readbuf
!= NULL
)
3883 memcpy (readbuf
, inf_siginfo
+ offset
, len
);
3886 memcpy (inf_siginfo
+ offset
, writebuf
, len
);
3888 /* Convert back to ptrace layout before flushing it out. */
3889 siginfo_fixup (&siginfo
, inf_siginfo
, 1);
3892 ptrace (PTRACE_SETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, &siginfo
);
3894 return TARGET_XFER_E_IO
;
3898 return TARGET_XFER_OK
;
3901 static enum target_xfer_status
3902 linux_nat_xfer_partial (struct target_ops
*ops
, enum target_object object
,
3903 const char *annex
, gdb_byte
*readbuf
,
3904 const gdb_byte
*writebuf
,
3905 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
3907 struct cleanup
*old_chain
;
3908 enum target_xfer_status xfer
;
3910 if (object
== TARGET_OBJECT_SIGNAL_INFO
)
3911 return linux_xfer_siginfo (ops
, object
, annex
, readbuf
, writebuf
,
3912 offset
, len
, xfered_len
);
3914 /* The target is connected but no live inferior is selected. Pass
3915 this request down to a lower stratum (e.g., the executable
3917 if (object
== TARGET_OBJECT_MEMORY
&& ptid_equal (inferior_ptid
, null_ptid
))
3918 return TARGET_XFER_EOF
;
3920 old_chain
= save_inferior_ptid ();
3922 if (ptid_lwp_p (inferior_ptid
))
3923 inferior_ptid
= pid_to_ptid (ptid_get_lwp (inferior_ptid
));
3925 xfer
= linux_ops
->to_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
3926 offset
, len
, xfered_len
);
3928 do_cleanups (old_chain
);
3933 linux_thread_alive (ptid_t ptid
)
3937 gdb_assert (ptid_lwp_p (ptid
));
3939 /* Send signal 0 instead of anything ptrace, because ptracing a
3940 running thread errors out claiming that the thread doesn't
3942 err
= kill_lwp (ptid_get_lwp (ptid
), 0);
3944 if (debug_linux_nat
)
3945 fprintf_unfiltered (gdb_stdlog
,
3946 "LLTA: KILL(SIG0) %s (%s)\n",
3947 target_pid_to_str (ptid
),
3948 err
? safe_strerror (tmp_errno
) : "OK");
3957 linux_nat_thread_alive (struct target_ops
*ops
, ptid_t ptid
)
3959 return linux_thread_alive (ptid
);
3963 linux_nat_pid_to_str (struct target_ops
*ops
, ptid_t ptid
)
3965 static char buf
[64];
3967 if (ptid_lwp_p (ptid
)
3968 && (ptid_get_pid (ptid
) != ptid_get_lwp (ptid
)
3969 || num_lwps (ptid_get_pid (ptid
)) > 1))
3971 snprintf (buf
, sizeof (buf
), "LWP %ld", ptid_get_lwp (ptid
));
3975 return normal_pid_to_str (ptid
);
3979 linux_nat_thread_name (struct target_ops
*self
, struct thread_info
*thr
)
3981 int pid
= ptid_get_pid (thr
->ptid
);
3982 long lwp
= ptid_get_lwp (thr
->ptid
);
3983 #define FORMAT "/proc/%d/task/%ld/comm"
3984 char buf
[sizeof (FORMAT
) + 30];
3986 char *result
= NULL
;
3988 snprintf (buf
, sizeof (buf
), FORMAT
, pid
, lwp
);
3989 comm_file
= gdb_fopen_cloexec (buf
, "r");
3992 /* Not exported by the kernel, so we define it here. */
3994 static char line
[COMM_LEN
+ 1];
3996 if (fgets (line
, sizeof (line
), comm_file
))
3998 char *nl
= strchr (line
, '\n');
4015 /* Accepts an integer PID; Returns a string representing a file that
4016 can be opened to get the symbols for the child process. */
4019 linux_child_pid_to_exec_file (struct target_ops
*self
, int pid
)
4021 static char buf
[PATH_MAX
];
4022 char name
[PATH_MAX
];
4024 xsnprintf (name
, PATH_MAX
, "/proc/%d/exe", pid
);
4025 memset (buf
, 0, PATH_MAX
);
4026 if (readlink (name
, buf
, PATH_MAX
- 1) <= 0)
4032 /* Records the thread's register state for the corefile note
4036 linux_nat_collect_thread_registers (const struct regcache
*regcache
,
4037 ptid_t ptid
, bfd
*obfd
,
4038 char *note_data
, int *note_size
,
4039 enum gdb_signal stop_signal
)
4041 struct gdbarch
*gdbarch
= get_regcache_arch (regcache
);
4042 const struct regset
*regset
;
4044 gdb_gregset_t gregs
;
4045 gdb_fpregset_t fpregs
;
4047 core_regset_p
= gdbarch_regset_from_core_section_p (gdbarch
);
4050 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg",
4052 != NULL
&& regset
->collect_regset
!= NULL
)
4053 regset
->collect_regset (regset
, regcache
, -1, &gregs
, sizeof (gregs
));
4055 fill_gregset (regcache
, &gregs
, -1);
4057 note_data
= (char *) elfcore_write_prstatus
4058 (obfd
, note_data
, note_size
, ptid_get_lwp (ptid
),
4059 gdb_signal_to_host (stop_signal
), &gregs
);
4062 && (regset
= gdbarch_regset_from_core_section (gdbarch
, ".reg2",
4064 != NULL
&& regset
->collect_regset
!= NULL
)
4065 regset
->collect_regset (regset
, regcache
, -1, &fpregs
, sizeof (fpregs
));
4067 fill_fpregset (regcache
, &fpregs
, -1);
4069 note_data
= (char *) elfcore_write_prfpreg (obfd
, note_data
, note_size
,
4070 &fpregs
, sizeof (fpregs
));
4075 /* Fills the "to_make_corefile_note" target vector. Builds the note
4076 section for a corefile, and returns it in a malloc buffer. */
4079 linux_nat_make_corefile_notes (struct target_ops
*self
,
4080 bfd
*obfd
, int *note_size
)
4082 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4083 converted to gdbarch_core_regset_sections, this function can go away. */
4084 return linux_make_corefile_notes (target_gdbarch (), obfd
, note_size
,
4085 linux_nat_collect_thread_registers
);
4088 /* Implement the to_xfer_partial interface for memory reads using the /proc
4089 filesystem. Because we can use a single read() call for /proc, this
4090 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4091 but it doesn't support writes. */
4093 static enum target_xfer_status
4094 linux_proc_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4095 const char *annex
, gdb_byte
*readbuf
,
4096 const gdb_byte
*writebuf
,
4097 ULONGEST offset
, LONGEST len
, ULONGEST
*xfered_len
)
4103 if (object
!= TARGET_OBJECT_MEMORY
|| !readbuf
)
4106 /* Don't bother for one word. */
4107 if (len
< 3 * sizeof (long))
4108 return TARGET_XFER_EOF
;
4110 /* We could keep this file open and cache it - possibly one per
4111 thread. That requires some juggling, but is even faster. */
4112 xsnprintf (filename
, sizeof filename
, "/proc/%d/mem",
4113 ptid_get_pid (inferior_ptid
));
4114 fd
= gdb_open_cloexec (filename
, O_RDONLY
| O_LARGEFILE
, 0);
4116 return TARGET_XFER_EOF
;
4118 /* If pread64 is available, use it. It's faster if the kernel
4119 supports it (only one syscall), and it's 64-bit safe even on
4120 32-bit platforms (for instance, SPARC debugging a SPARC64
4123 if (pread64 (fd
, readbuf
, len
, offset
) != len
)
4125 if (lseek (fd
, offset
, SEEK_SET
) == -1 || read (fd
, readbuf
, len
) != len
)
4134 return TARGET_XFER_EOF
;
4138 return TARGET_XFER_OK
;
4143 /* Enumerate spufs IDs for process PID. */
4145 spu_enumerate_spu_ids (int pid
, gdb_byte
*buf
, ULONGEST offset
, ULONGEST len
)
4147 enum bfd_endian byte_order
= gdbarch_byte_order (target_gdbarch ());
4149 LONGEST written
= 0;
4152 struct dirent
*entry
;
4154 xsnprintf (path
, sizeof path
, "/proc/%d/fd", pid
);
4155 dir
= opendir (path
);
4160 while ((entry
= readdir (dir
)) != NULL
)
4166 fd
= atoi (entry
->d_name
);
4170 xsnprintf (path
, sizeof path
, "/proc/%d/fd/%d", pid
, fd
);
4171 if (stat (path
, &st
) != 0)
4173 if (!S_ISDIR (st
.st_mode
))
4176 if (statfs (path
, &stfs
) != 0)
4178 if (stfs
.f_type
!= SPUFS_MAGIC
)
4181 if (pos
>= offset
&& pos
+ 4 <= offset
+ len
)
4183 store_unsigned_integer (buf
+ pos
- offset
, 4, byte_order
, fd
);
4193 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4194 object type, using the /proc file system. */
4196 static enum target_xfer_status
4197 linux_proc_xfer_spu (struct target_ops
*ops
, enum target_object object
,
4198 const char *annex
, gdb_byte
*readbuf
,
4199 const gdb_byte
*writebuf
,
4200 ULONGEST offset
, ULONGEST len
, ULONGEST
*xfered_len
)
4205 int pid
= ptid_get_pid (inferior_ptid
);
4210 return TARGET_XFER_E_IO
;
4213 LONGEST l
= spu_enumerate_spu_ids (pid
, readbuf
, offset
, len
);
4216 return TARGET_XFER_E_IO
;
4218 return TARGET_XFER_EOF
;
4221 *xfered_len
= (ULONGEST
) l
;
4222 return TARGET_XFER_OK
;
4227 xsnprintf (buf
, sizeof buf
, "/proc/%d/fd/%s", pid
, annex
);
4228 fd
= gdb_open_cloexec (buf
, writebuf
? O_WRONLY
: O_RDONLY
, 0);
4230 return TARGET_XFER_E_IO
;
4233 && lseek (fd
, (off_t
) offset
, SEEK_SET
) != (off_t
) offset
)
4236 return TARGET_XFER_EOF
;
4240 ret
= write (fd
, writebuf
, (size_t) len
);
4242 ret
= read (fd
, readbuf
, (size_t) len
);
4247 return TARGET_XFER_E_IO
;
4249 return TARGET_XFER_EOF
;
4252 *xfered_len
= (ULONGEST
) ret
;
4253 return TARGET_XFER_OK
;
4258 /* Parse LINE as a signal set and add its set bits to SIGS. */
4261 add_line_to_sigset (const char *line
, sigset_t
*sigs
)
4263 int len
= strlen (line
) - 1;
4267 if (line
[len
] != '\n')
4268 error (_("Could not parse signal set: %s"), line
);
4276 if (*p
>= '0' && *p
<= '9')
4278 else if (*p
>= 'a' && *p
<= 'f')
4279 digit
= *p
- 'a' + 10;
4281 error (_("Could not parse signal set: %s"), line
);
4286 sigaddset (sigs
, signum
+ 1);
4288 sigaddset (sigs
, signum
+ 2);
4290 sigaddset (sigs
, signum
+ 3);
4292 sigaddset (sigs
, signum
+ 4);
4298 /* Find process PID's pending signals from /proc/pid/status and set
4302 linux_proc_pending_signals (int pid
, sigset_t
*pending
,
4303 sigset_t
*blocked
, sigset_t
*ignored
)
4306 char buffer
[PATH_MAX
], fname
[PATH_MAX
];
4307 struct cleanup
*cleanup
;
4309 sigemptyset (pending
);
4310 sigemptyset (blocked
);
4311 sigemptyset (ignored
);
4312 xsnprintf (fname
, sizeof fname
, "/proc/%d/status", pid
);
4313 procfile
= gdb_fopen_cloexec (fname
, "r");
4314 if (procfile
== NULL
)
4315 error (_("Could not open %s"), fname
);
4316 cleanup
= make_cleanup_fclose (procfile
);
4318 while (fgets (buffer
, PATH_MAX
, procfile
) != NULL
)
4320 /* Normal queued signals are on the SigPnd line in the status
4321 file. However, 2.6 kernels also have a "shared" pending
4322 queue for delivering signals to a thread group, so check for
4325 Unfortunately some Red Hat kernels include the shared pending
4326 queue but not the ShdPnd status field. */
4328 if (strncmp (buffer
, "SigPnd:\t", 8) == 0)
4329 add_line_to_sigset (buffer
+ 8, pending
);
4330 else if (strncmp (buffer
, "ShdPnd:\t", 8) == 0)
4331 add_line_to_sigset (buffer
+ 8, pending
);
4332 else if (strncmp (buffer
, "SigBlk:\t", 8) == 0)
4333 add_line_to_sigset (buffer
+ 8, blocked
);
4334 else if (strncmp (buffer
, "SigIgn:\t", 8) == 0)
4335 add_line_to_sigset (buffer
+ 8, ignored
);
4338 do_cleanups (cleanup
);
4341 static enum target_xfer_status
4342 linux_nat_xfer_osdata (struct target_ops
*ops
, enum target_object object
,
4343 const char *annex
, gdb_byte
*readbuf
,
4344 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4345 ULONGEST
*xfered_len
)
4347 gdb_assert (object
== TARGET_OBJECT_OSDATA
);
4349 *xfered_len
= linux_common_xfer_osdata (annex
, readbuf
, offset
, len
);
4350 if (*xfered_len
== 0)
4351 return TARGET_XFER_EOF
;
4353 return TARGET_XFER_OK
;
4356 static enum target_xfer_status
4357 linux_xfer_partial (struct target_ops
*ops
, enum target_object object
,
4358 const char *annex
, gdb_byte
*readbuf
,
4359 const gdb_byte
*writebuf
, ULONGEST offset
, ULONGEST len
,
4360 ULONGEST
*xfered_len
)
4362 enum target_xfer_status xfer
;
4364 if (object
== TARGET_OBJECT_AUXV
)
4365 return memory_xfer_auxv (ops
, object
, annex
, readbuf
, writebuf
,
4366 offset
, len
, xfered_len
);
4368 if (object
== TARGET_OBJECT_OSDATA
)
4369 return linux_nat_xfer_osdata (ops
, object
, annex
, readbuf
, writebuf
,
4370 offset
, len
, xfered_len
);
4372 if (object
== TARGET_OBJECT_SPU
)
4373 return linux_proc_xfer_spu (ops
, object
, annex
, readbuf
, writebuf
,
4374 offset
, len
, xfered_len
);
4376 /* GDB calculates all the addresses in possibly larget width of the address.
4377 Address width needs to be masked before its final use - either by
4378 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4380 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4382 if (object
== TARGET_OBJECT_MEMORY
)
4384 int addr_bit
= gdbarch_addr_bit (target_gdbarch ());
4386 if (addr_bit
< (sizeof (ULONGEST
) * HOST_CHAR_BIT
))
4387 offset
&= ((ULONGEST
) 1 << addr_bit
) - 1;
4390 xfer
= linux_proc_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4391 offset
, len
, xfered_len
);
4392 if (xfer
!= TARGET_XFER_EOF
)
4395 return super_xfer_partial (ops
, object
, annex
, readbuf
, writebuf
,
4396 offset
, len
, xfered_len
);
4400 cleanup_target_stop (void *arg
)
4402 ptid_t
*ptid
= (ptid_t
*) arg
;
4404 gdb_assert (arg
!= NULL
);
4407 target_resume (*ptid
, 0, GDB_SIGNAL_0
);
4410 static VEC(static_tracepoint_marker_p
) *
4411 linux_child_static_tracepoint_markers_by_strid (struct target_ops
*self
,
4414 char s
[IPA_CMD_BUF_SIZE
];
4415 struct cleanup
*old_chain
;
4416 int pid
= ptid_get_pid (inferior_ptid
);
4417 VEC(static_tracepoint_marker_p
) *markers
= NULL
;
4418 struct static_tracepoint_marker
*marker
= NULL
;
4420 ptid_t ptid
= ptid_build (pid
, 0, 0);
4425 memcpy (s
, "qTfSTM", sizeof ("qTfSTM"));
4426 s
[sizeof ("qTfSTM")] = 0;
4428 agent_run_command (pid
, s
, strlen (s
) + 1);
4430 old_chain
= make_cleanup (free_current_marker
, &marker
);
4431 make_cleanup (cleanup_target_stop
, &ptid
);
4436 marker
= XCNEW (struct static_tracepoint_marker
);
4440 parse_static_tracepoint_marker_definition (p
, &p
, marker
);
4442 if (strid
== NULL
|| strcmp (strid
, marker
->str_id
) == 0)
4444 VEC_safe_push (static_tracepoint_marker_p
,
4450 release_static_tracepoint_marker (marker
);
4451 memset (marker
, 0, sizeof (*marker
));
4454 while (*p
++ == ','); /* comma-separated list */
4456 memcpy (s
, "qTsSTM", sizeof ("qTsSTM"));
4457 s
[sizeof ("qTsSTM")] = 0;
4458 agent_run_command (pid
, s
, strlen (s
) + 1);
4462 do_cleanups (old_chain
);
4467 /* Create a prototype generic GNU/Linux target. The client can override
4468 it with local methods. */
4471 linux_target_install_ops (struct target_ops
*t
)
4473 t
->to_insert_fork_catchpoint
= linux_child_insert_fork_catchpoint
;
4474 t
->to_remove_fork_catchpoint
= linux_child_remove_fork_catchpoint
;
4475 t
->to_insert_vfork_catchpoint
= linux_child_insert_vfork_catchpoint
;
4476 t
->to_remove_vfork_catchpoint
= linux_child_remove_vfork_catchpoint
;
4477 t
->to_insert_exec_catchpoint
= linux_child_insert_exec_catchpoint
;
4478 t
->to_remove_exec_catchpoint
= linux_child_remove_exec_catchpoint
;
4479 t
->to_set_syscall_catchpoint
= linux_child_set_syscall_catchpoint
;
4480 t
->to_pid_to_exec_file
= linux_child_pid_to_exec_file
;
4481 t
->to_post_startup_inferior
= linux_child_post_startup_inferior
;
4482 t
->to_post_attach
= linux_child_post_attach
;
4483 t
->to_follow_fork
= linux_child_follow_fork
;
4484 t
->to_make_corefile_notes
= linux_nat_make_corefile_notes
;
4486 super_xfer_partial
= t
->to_xfer_partial
;
4487 t
->to_xfer_partial
= linux_xfer_partial
;
4489 t
->to_static_tracepoint_markers_by_strid
4490 = linux_child_static_tracepoint_markers_by_strid
;
4496 struct target_ops
*t
;
4498 t
= inf_ptrace_target ();
4499 linux_target_install_ops (t
);
4505 linux_trad_target (CORE_ADDR (*register_u_offset
)(struct gdbarch
*, int, int))
4507 struct target_ops
*t
;
4509 t
= inf_ptrace_trad_target (register_u_offset
);
4510 linux_target_install_ops (t
);
4515 /* target_is_async_p implementation. */
4518 linux_nat_is_async_p (struct target_ops
*ops
)
4520 /* NOTE: palves 2008-03-21: We're only async when the user requests
4521 it explicitly with the "set target-async" command.
4522 Someday, linux will always be async. */
4523 return target_async_permitted
;
4526 /* target_can_async_p implementation. */
4529 linux_nat_can_async_p (struct target_ops
*ops
)
4531 /* NOTE: palves 2008-03-21: We're only async when the user requests
4532 it explicitly with the "set target-async" command.
4533 Someday, linux will always be async. */
4534 return target_async_permitted
;
4538 linux_nat_supports_non_stop (struct target_ops
*self
)
4543 /* True if we want to support multi-process. To be removed when GDB
4544 supports multi-exec. */
4546 int linux_multi_process
= 1;
4549 linux_nat_supports_multi_process (struct target_ops
*self
)
4551 return linux_multi_process
;
4555 linux_nat_supports_disable_randomization (struct target_ops
*self
)
4557 #ifdef HAVE_PERSONALITY
4564 static int async_terminal_is_ours
= 1;
4566 /* target_terminal_inferior implementation. */
4569 linux_nat_terminal_inferior (struct target_ops
*self
)
4571 if (!target_is_async_p ())
4573 /* Async mode is disabled. */
4574 child_terminal_inferior (self
);
4578 child_terminal_inferior (self
);
4580 /* Calls to target_terminal_*() are meant to be idempotent. */
4581 if (!async_terminal_is_ours
)
4584 delete_file_handler (input_fd
);
4585 async_terminal_is_ours
= 0;
4589 /* target_terminal_ours implementation. */
4592 linux_nat_terminal_ours (struct target_ops
*self
)
4594 if (!target_is_async_p ())
4596 /* Async mode is disabled. */
4597 child_terminal_ours (self
);
4601 /* GDB should never give the terminal to the inferior if the
4602 inferior is running in the background (run&, continue&, etc.),
4603 but claiming it sure should. */
4604 child_terminal_ours (self
);
4606 if (async_terminal_is_ours
)
4609 clear_sigint_trap ();
4610 add_file_handler (input_fd
, stdin_event_handler
, 0);
4611 async_terminal_is_ours
= 1;
4614 static void (*async_client_callback
) (enum inferior_event_type event_type
,
4616 static void *async_client_context
;
4618 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4619 so we notice when any child changes state, and notify the
4620 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4621 above to wait for the arrival of a SIGCHLD. */
4624 sigchld_handler (int signo
)
4626 int old_errno
= errno
;
4628 if (debug_linux_nat
)
4629 ui_file_write_async_safe (gdb_stdlog
,
4630 "sigchld\n", sizeof ("sigchld\n") - 1);
4632 if (signo
== SIGCHLD
4633 && linux_nat_event_pipe
[0] != -1)
4634 async_file_mark (); /* Let the event loop know that there are
4635 events to handle. */
4640 /* Callback registered with the target events file descriptor. */
4643 handle_target_event (int error
, gdb_client_data client_data
)
4645 (*async_client_callback
) (INF_REG_EVENT
, async_client_context
);
4648 /* Create/destroy the target events pipe. Returns previous state. */
4651 linux_async_pipe (int enable
)
4653 int previous
= (linux_nat_event_pipe
[0] != -1);
4655 if (previous
!= enable
)
4659 /* Block child signals while we create/destroy the pipe, as
4660 their handler writes to it. */
4661 block_child_signals (&prev_mask
);
4665 if (gdb_pipe_cloexec (linux_nat_event_pipe
) == -1)
4666 internal_error (__FILE__
, __LINE__
,
4667 "creating event pipe failed.");
4669 fcntl (linux_nat_event_pipe
[0], F_SETFL
, O_NONBLOCK
);
4670 fcntl (linux_nat_event_pipe
[1], F_SETFL
, O_NONBLOCK
);
4674 close (linux_nat_event_pipe
[0]);
4675 close (linux_nat_event_pipe
[1]);
4676 linux_nat_event_pipe
[0] = -1;
4677 linux_nat_event_pipe
[1] = -1;
4680 restore_child_signals_mask (&prev_mask
);
4686 /* target_async implementation. */
4689 linux_nat_async (struct target_ops
*ops
,
4690 void (*callback
) (enum inferior_event_type event_type
,
4694 if (callback
!= NULL
)
4696 async_client_callback
= callback
;
4697 async_client_context
= context
;
4698 if (!linux_async_pipe (1))
4700 add_file_handler (linux_nat_event_pipe
[0],
4701 handle_target_event
, NULL
);
4702 /* There may be pending events to handle. Tell the event loop
4709 async_client_callback
= callback
;
4710 async_client_context
= context
;
4711 delete_file_handler (linux_nat_event_pipe
[0]);
4712 linux_async_pipe (0);
4717 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4721 linux_nat_stop_lwp (struct lwp_info
*lwp
, void *data
)
4725 if (debug_linux_nat
)
4726 fprintf_unfiltered (gdb_stdlog
,
4727 "LNSL: running -> suspending %s\n",
4728 target_pid_to_str (lwp
->ptid
));
4731 if (lwp
->last_resume_kind
== resume_stop
)
4733 if (debug_linux_nat
)
4734 fprintf_unfiltered (gdb_stdlog
,
4735 "linux-nat: already stopping LWP %ld at "
4737 ptid_get_lwp (lwp
->ptid
));
4741 stop_callback (lwp
, NULL
);
4742 lwp
->last_resume_kind
= resume_stop
;
4746 /* Already known to be stopped; do nothing. */
4748 if (debug_linux_nat
)
4750 if (find_thread_ptid (lwp
->ptid
)->stop_requested
)
4751 fprintf_unfiltered (gdb_stdlog
,
4752 "LNSL: already stopped/stop_requested %s\n",
4753 target_pid_to_str (lwp
->ptid
));
4755 fprintf_unfiltered (gdb_stdlog
,
4756 "LNSL: already stopped/no "
4757 "stop_requested yet %s\n",
4758 target_pid_to_str (lwp
->ptid
));
4765 linux_nat_stop (struct target_ops
*self
, ptid_t ptid
)
4768 iterate_over_lwps (ptid
, linux_nat_stop_lwp
, NULL
);
4770 linux_ops
->to_stop (linux_ops
, ptid
);
4774 linux_nat_close (struct target_ops
*self
)
4776 /* Unregister from the event loop. */
4777 if (linux_nat_is_async_p (NULL
))
4778 linux_nat_async (NULL
, NULL
, 0);
4780 if (linux_ops
->to_close
)
4781 linux_ops
->to_close (linux_ops
);
4786 /* When requests are passed down from the linux-nat layer to the
4787 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4788 used. The address space pointer is stored in the inferior object,
4789 but the common code that is passed such ptid can't tell whether
4790 lwpid is a "main" process id or not (it assumes so). We reverse
4791 look up the "main" process id from the lwp here. */
4793 static struct address_space
*
4794 linux_nat_thread_address_space (struct target_ops
*t
, ptid_t ptid
)
4796 struct lwp_info
*lwp
;
4797 struct inferior
*inf
;
4800 pid
= ptid_get_lwp (ptid
);
4801 if (ptid_get_lwp (ptid
) == 0)
4803 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4805 lwp
= find_lwp_pid (ptid
);
4806 pid
= ptid_get_pid (lwp
->ptid
);
4810 /* A (pid,lwpid,0) ptid. */
4811 pid
= ptid_get_pid (ptid
);
4814 inf
= find_inferior_pid (pid
);
4815 gdb_assert (inf
!= NULL
);
4819 /* Return the cached value of the processor core for thread PTID. */
4822 linux_nat_core_of_thread (struct target_ops
*ops
, ptid_t ptid
)
4824 struct lwp_info
*info
= find_lwp_pid (ptid
);
4832 linux_nat_add_target (struct target_ops
*t
)
4834 /* Save the provided single-threaded target. We save this in a separate
4835 variable because another target we've inherited from (e.g. inf-ptrace)
4836 may have saved a pointer to T; we want to use it for the final
4837 process stratum target. */
4838 linux_ops_saved
= *t
;
4839 linux_ops
= &linux_ops_saved
;
4841 /* Override some methods for multithreading. */
4842 t
->to_create_inferior
= linux_nat_create_inferior
;
4843 t
->to_attach
= linux_nat_attach
;
4844 t
->to_detach
= linux_nat_detach
;
4845 t
->to_resume
= linux_nat_resume
;
4846 t
->to_wait
= linux_nat_wait
;
4847 t
->to_pass_signals
= linux_nat_pass_signals
;
4848 t
->to_xfer_partial
= linux_nat_xfer_partial
;
4849 t
->to_kill
= linux_nat_kill
;
4850 t
->to_mourn_inferior
= linux_nat_mourn_inferior
;
4851 t
->to_thread_alive
= linux_nat_thread_alive
;
4852 t
->to_pid_to_str
= linux_nat_pid_to_str
;
4853 t
->to_thread_name
= linux_nat_thread_name
;
4854 t
->to_has_thread_control
= tc_schedlock
;
4855 t
->to_thread_address_space
= linux_nat_thread_address_space
;
4856 t
->to_stopped_by_watchpoint
= linux_nat_stopped_by_watchpoint
;
4857 t
->to_stopped_data_address
= linux_nat_stopped_data_address
;
4859 t
->to_can_async_p
= linux_nat_can_async_p
;
4860 t
->to_is_async_p
= linux_nat_is_async_p
;
4861 t
->to_supports_non_stop
= linux_nat_supports_non_stop
;
4862 t
->to_async
= linux_nat_async
;
4863 t
->to_terminal_inferior
= linux_nat_terminal_inferior
;
4864 t
->to_terminal_ours
= linux_nat_terminal_ours
;
4866 super_close
= t
->to_close
;
4867 t
->to_close
= linux_nat_close
;
4869 /* Methods for non-stop support. */
4870 t
->to_stop
= linux_nat_stop
;
4872 t
->to_supports_multi_process
= linux_nat_supports_multi_process
;
4874 t
->to_supports_disable_randomization
4875 = linux_nat_supports_disable_randomization
;
4877 t
->to_core_of_thread
= linux_nat_core_of_thread
;
4879 /* We don't change the stratum; this target will sit at
4880 process_stratum and thread_db will set at thread_stratum. This
4881 is a little strange, since this is a multi-threaded-capable
4882 target, but we want to be on the stack below thread_db, and we
4883 also want to be used for single-threaded processes. */
4888 /* Register a method to call whenever a new thread is attached. */
4890 linux_nat_set_new_thread (struct target_ops
*t
,
4891 void (*new_thread
) (struct lwp_info
*))
4893 /* Save the pointer. We only support a single registered instance
4894 of the GNU/Linux native target, so we do not need to map this to
4896 linux_nat_new_thread
= new_thread
;
4899 /* See declaration in linux-nat.h. */
4902 linux_nat_set_new_fork (struct target_ops
*t
,
4903 linux_nat_new_fork_ftype
*new_fork
)
4905 /* Save the pointer. */
4906 linux_nat_new_fork
= new_fork
;
4909 /* See declaration in linux-nat.h. */
4912 linux_nat_set_forget_process (struct target_ops
*t
,
4913 linux_nat_forget_process_ftype
*fn
)
4915 /* Save the pointer. */
4916 linux_nat_forget_process_hook
= fn
;
4919 /* See declaration in linux-nat.h. */
4922 linux_nat_forget_process (pid_t pid
)
4924 if (linux_nat_forget_process_hook
!= NULL
)
4925 linux_nat_forget_process_hook (pid
);
4928 /* Register a method that converts a siginfo object between the layout
4929 that ptrace returns, and the layout in the architecture of the
4932 linux_nat_set_siginfo_fixup (struct target_ops
*t
,
4933 int (*siginfo_fixup
) (siginfo_t
*,
4937 /* Save the pointer. */
4938 linux_nat_siginfo_fixup
= siginfo_fixup
;
4941 /* Register a method to call prior to resuming a thread. */
4944 linux_nat_set_prepare_to_resume (struct target_ops
*t
,
4945 void (*prepare_to_resume
) (struct lwp_info
*))
4947 /* Save the pointer. */
4948 linux_nat_prepare_to_resume
= prepare_to_resume
;
4951 /* See linux-nat.h. */
4954 linux_nat_get_siginfo (ptid_t ptid
, siginfo_t
*siginfo
)
4958 pid
= ptid_get_lwp (ptid
);
4960 pid
= ptid_get_pid (ptid
);
4963 ptrace (PTRACE_GETSIGINFO
, pid
, (PTRACE_TYPE_ARG3
) 0, siginfo
);
4966 memset (siginfo
, 0, sizeof (*siginfo
));
4972 /* Provide a prototype to silence -Wmissing-prototypes. */
4973 extern initialize_file_ftype _initialize_linux_nat
;
4976 _initialize_linux_nat (void)
4978 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance
,
4979 &debug_linux_nat
, _("\
4980 Set debugging of GNU/Linux lwp module."), _("\
4981 Show debugging of GNU/Linux lwp module."), _("\
4982 Enables printf debugging output."),
4984 show_debug_linux_nat
,
4985 &setdebuglist
, &showdebuglist
);
4987 /* Save this mask as the default. */
4988 sigprocmask (SIG_SETMASK
, NULL
, &normal_mask
);
4990 /* Install a SIGCHLD handler. */
4991 sigchld_action
.sa_handler
= sigchld_handler
;
4992 sigemptyset (&sigchld_action
.sa_mask
);
4993 sigchld_action
.sa_flags
= SA_RESTART
;
4995 /* Make it the default. */
4996 sigaction (SIGCHLD
, &sigchld_action
, NULL
);
4998 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4999 sigprocmask (SIG_SETMASK
, NULL
, &suspend_mask
);
5000 sigdelset (&suspend_mask
, SIGCHLD
);
5002 sigemptyset (&blocked_mask
);
5006 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
5007 the GNU/Linux Threads library and therefore doesn't really belong
5010 /* Read variable NAME in the target and return its value if found.
5011 Otherwise return zero. It is assumed that the type of the variable
5015 get_signo (const char *name
)
5017 struct bound_minimal_symbol ms
;
5020 ms
= lookup_minimal_symbol (name
, NULL
, NULL
);
5021 if (ms
.minsym
== NULL
)
5024 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms
), (gdb_byte
*) &signo
,
5025 sizeof (signo
)) != 0)
5031 /* Return the set of signals used by the threads library in *SET. */
5034 lin_thread_get_thread_signals (sigset_t
*set
)
5036 struct sigaction action
;
5037 int restart
, cancel
;
5039 sigemptyset (&blocked_mask
);
5042 restart
= get_signo ("__pthread_sig_restart");
5043 cancel
= get_signo ("__pthread_sig_cancel");
5045 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5046 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5047 not provide any way for the debugger to query the signal numbers -
5048 fortunately they don't change! */
5051 restart
= __SIGRTMIN
;
5054 cancel
= __SIGRTMIN
+ 1;
5056 sigaddset (set
, restart
);
5057 sigaddset (set
, cancel
);
5059 /* The GNU/Linux Threads library makes terminating threads send a
5060 special "cancel" signal instead of SIGCHLD. Make sure we catch
5061 those (to prevent them from terminating GDB itself, which is
5062 likely to be their default action) and treat them the same way as
5065 action
.sa_handler
= sigchld_handler
;
5066 sigemptyset (&action
.sa_mask
);
5067 action
.sa_flags
= SA_RESTART
;
5068 sigaction (cancel
, &action
, NULL
);
5070 /* We block the "cancel" signal throughout this code ... */
5071 sigaddset (&blocked_mask
, cancel
);
5072 sigprocmask (SIG_BLOCK
, &blocked_mask
, NULL
);
5074 /* ... except during a sigsuspend. */
5075 sigdelset (&suspend_mask
, cancel
);