1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2014 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "nat/linux-nat.h"
24 #include "nat/linux-waitpid.h"
27 #include "gdb_assert.h"
28 #ifdef HAVE_TKILL_SYSCALL
30 #include <sys/syscall.h>
32 #include <sys/ptrace.h>
33 #include "linux-nat.h"
34 #include "linux-ptrace.h"
35 #include "linux-procfs.h"
36 #include "linux-fork.h"
37 #include "gdbthread.h"
41 #include "inf-child.h"
42 #include "inf-ptrace.h"
44 #include <sys/procfs.h> /* for elf_gregset etc. */
45 #include "elf-bfd.h" /* for elfcore_write_* */
46 #include "gregset.h" /* for gregset */
47 #include "gdbcore.h" /* for get_exec_file */
48 #include <ctype.h> /* for isdigit */
49 #include <sys/stat.h> /* for struct stat */
50 #include <fcntl.h> /* for O_RDONLY */
52 #include "event-loop.h"
53 #include "event-top.h"
55 #include <sys/types.h>
57 #include "xml-support.h"
61 #include "linux-osdata.h"
62 #include "linux-tdep.h"
65 #include "tracepoint.h"
66 #include "exceptions.h"
68 #include "target-descriptions.h"
69 #include "filestuff.h"
73 #define SPUFS_MAGIC 0x23c9b64e
76 #ifdef HAVE_PERSONALITY
77 # include <sys/personality.h>
78 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
79 # define ADDR_NO_RANDOMIZE 0x0040000
81 #endif /* HAVE_PERSONALITY */
83 /* This comment documents high-level logic of this file.
85 Waiting for events in sync mode
86 ===============================
88 When waiting for an event in a specific thread, we just use waitpid, passing
89 the specific pid, and not passing WNOHANG.
91 When waiting for an event in all threads, waitpid is not quite good. Prior to
92 version 2.4, Linux can either wait for event in main thread, or in secondary
93 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
94 miss an event. The solution is to use non-blocking waitpid, together with
95 sigsuspend. First, we use non-blocking waitpid to get an event in the main
96 process, if any. Second, we use non-blocking waitpid with the __WCLONED
97 flag to check for events in cloned processes. If nothing is found, we use
98 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
99 happened to a child process -- and SIGCHLD will be delivered both for events
100 in main debugged process and in cloned processes. As soon as we know there's
101 an event, we get back to calling nonblocking waitpid with and without
104 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
105 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
106 blocked, the signal becomes pending and sigsuspend immediately
107 notices it and returns.
109 Waiting for events in async mode
110 ================================
112 In async mode, GDB should always be ready to handle both user input
113 and target events, so neither blocking waitpid nor sigsuspend are
114 viable options. Instead, we should asynchronously notify the GDB main
115 event loop whenever there's an unprocessed event from the target. We
116 detect asynchronous target events by handling SIGCHLD signals. To
117 notify the event loop about target events, the self-pipe trick is used
118 --- a pipe is registered as waitable event source in the event loop,
119 the event loop select/poll's on the read end of this pipe (as well on
120 other event sources, e.g., stdin), and the SIGCHLD handler writes a
121 byte to this pipe. This is more portable than relying on
122 pselect/ppoll, since on kernels that lack those syscalls, libc
123 emulates them with select/poll+sigprocmask, and that is racy
124 (a.k.a. plain broken).
126 Obviously, if we fail to notify the event loop if there's a target
127 event, it's bad. OTOH, if we notify the event loop when there's no
128 event from the target, linux_nat_wait will detect that there's no real
129 event to report, and return event of type TARGET_WAITKIND_IGNORE.
130 This is mostly harmless, but it will waste time and is better avoided.
132 The main design point is that every time GDB is outside linux-nat.c,
133 we have a SIGCHLD handler installed that is called when something
134 happens to the target and notifies the GDB event loop. Whenever GDB
135 core decides to handle the event, and calls into linux-nat.c, we
136 process things as in sync mode, except that the we never block in
139 While processing an event, we may end up momentarily blocked in
140 waitpid calls. Those waitpid calls, while blocking, are guarantied to
141 return quickly. E.g., in all-stop mode, before reporting to the core
142 that an LWP hit a breakpoint, all LWPs are stopped by sending them
143 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
144 Note that this is different from blocking indefinitely waiting for the
145 next event --- here, we're already handling an event.
150 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
151 signal is not entirely significant; we just need for a signal to be delivered,
152 so that we can intercept it. SIGSTOP's advantage is that it can not be
153 blocked. A disadvantage is that it is not a real-time signal, so it can only
154 be queued once; we do not keep track of other sources of SIGSTOP.
156 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
157 use them, because they have special behavior when the signal is generated -
158 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
159 kills the entire thread group.
161 A delivered SIGSTOP would stop the entire thread group, not just the thread we
162 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
163 cancel it (by PTRACE_CONT without passing SIGSTOP).
165 We could use a real-time signal instead. This would solve those problems; we
166 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
167 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
168 generates it, and there are races with trying to find a signal that is not
172 #define O_LARGEFILE 0
175 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
176 the use of the multi-threaded target. */
177 static struct target_ops *linux_ops;
178 static struct target_ops linux_ops_saved;
180 /* The method to call, if any, when a new thread is attached. */
181 static void (*linux_nat_new_thread) (struct lwp_info *);
183 /* The method to call, if any, when a new fork is attached. */
184 static linux_nat_new_fork_ftype *linux_nat_new_fork;
186 /* The method to call, if any, when a process is no longer
188 static linux_nat_forget_process_ftype *linux_nat_forget_process_hook;
190 /* Hook to call prior to resuming a thread. */
191 static void (*linux_nat_prepare_to_resume) (struct lwp_info *);
193 /* The method to call, if any, when the siginfo object needs to be
194 converted between the layout returned by ptrace, and the layout in
195 the architecture of the inferior. */
196 static int (*linux_nat_siginfo_fixup) (siginfo_t *,
200 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
201 Called by our to_xfer_partial. */
202 static target_xfer_partial_ftype *super_xfer_partial;
204 static unsigned int debug_linux_nat;
206 show_debug_linux_nat (struct ui_file *file, int from_tty,
207 struct cmd_list_element *c, const char *value)
209 fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
213 struct simple_pid_list
217 struct simple_pid_list *next;
219 struct simple_pid_list *stopped_pids;
221 /* Async mode support. */
223 /* The read/write ends of the pipe registered as waitable file in the
225 static int linux_nat_event_pipe[2] = { -1, -1 };
227 /* Flush the event pipe. */
230 async_file_flush (void)
237 ret = read (linux_nat_event_pipe[0], &buf, 1);
239 while (ret >= 0 || (ret == -1 && errno == EINTR));
242 /* Put something (anything, doesn't matter what, or how much) in event
243 pipe, so that the select/poll in the event-loop realizes we have
244 something to process. */
247 async_file_mark (void)
251 /* It doesn't really matter what the pipe contains, as long we end
252 up with something in it. Might as well flush the previous
258 ret = write (linux_nat_event_pipe[1], "+", 1);
260 while (ret == -1 && errno == EINTR);
262 /* Ignore EAGAIN. If the pipe is full, the event loop will already
263 be awakened anyway. */
266 static int kill_lwp (int lwpid, int signo);
268 static int stop_callback (struct lwp_info *lp, void *data);
270 static void block_child_signals (sigset_t *prev_mask);
271 static void restore_child_signals_mask (sigset_t *prev_mask);
274 static struct lwp_info *add_lwp (ptid_t ptid);
275 static void purge_lwp_list (int pid);
276 static void delete_lwp (ptid_t ptid);
277 static struct lwp_info *find_lwp_pid (ptid_t ptid);
280 /* Trivial list manipulation functions to keep track of a list of
281 new stopped processes. */
283 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
285 struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
288 new_pid->status = status;
289 new_pid->next = *listp;
294 in_pid_list_p (struct simple_pid_list *list, int pid)
296 struct simple_pid_list *p;
298 for (p = list; p != NULL; p = p->next)
305 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
307 struct simple_pid_list **p;
309 for (p = listp; *p != NULL; p = &(*p)->next)
310 if ((*p)->pid == pid)
312 struct simple_pid_list *next = (*p)->next;
314 *statusp = (*p)->status;
322 /* Initialize ptrace warnings and check for supported ptrace
323 features given PID. */
326 linux_init_ptrace (pid_t pid)
328 linux_enable_event_reporting (pid);
329 linux_ptrace_init_warnings ();
333 linux_child_post_attach (struct target_ops *self, int pid)
335 linux_init_ptrace (pid);
339 linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
341 linux_init_ptrace (ptid_get_pid (ptid));
344 /* Return the number of known LWPs in the tgid given by PID. */
352 for (lp = lwp_list; lp; lp = lp->next)
353 if (ptid_get_pid (lp->ptid) == pid)
359 /* Call delete_lwp with prototype compatible for make_cleanup. */
362 delete_lwp_cleanup (void *lp_voidp)
364 struct lwp_info *lp = lp_voidp;
366 delete_lwp (lp->ptid);
370 linux_child_follow_fork (struct target_ops *ops, int follow_child,
374 int parent_pid, child_pid;
376 has_vforked = (inferior_thread ()->pending_follow.kind
377 == TARGET_WAITKIND_VFORKED);
378 parent_pid = ptid_get_lwp (inferior_ptid);
380 parent_pid = ptid_get_pid (inferior_ptid);
382 = ptid_get_pid (inferior_thread ()->pending_follow.value.related_pid);
385 && !non_stop /* Non-stop always resumes both branches. */
386 && (!target_is_async_p () || sync_execution)
387 && !(follow_child || detach_fork || sched_multi))
389 /* The parent stays blocked inside the vfork syscall until the
390 child execs or exits. If we don't let the child run, then
391 the parent stays blocked. If we're telling the parent to run
392 in the foreground, the user will not be able to ctrl-c to get
393 back the terminal, effectively hanging the debug session. */
394 fprintf_filtered (gdb_stderr, _("\
395 Can not resume the parent process over vfork in the foreground while\n\
396 holding the child stopped. Try \"set detach-on-fork\" or \
397 \"set schedule-multiple\".\n"));
398 /* FIXME output string > 80 columns. */
404 struct lwp_info *child_lp = NULL;
406 /* We're already attached to the parent, by default. */
408 /* Detach new forked process? */
411 struct cleanup *old_chain;
413 /* Before detaching from the child, remove all breakpoints
414 from it. If we forked, then this has already been taken
415 care of by infrun.c. If we vforked however, any
416 breakpoint inserted in the parent is visible in the
417 child, even those added while stopped in a vfork
418 catchpoint. This will remove the breakpoints from the
419 parent also, but they'll be reinserted below. */
422 /* keep breakpoints list in sync. */
423 remove_breakpoints_pid (ptid_get_pid (inferior_ptid));
426 if (info_verbose || debug_linux_nat)
428 target_terminal_ours ();
429 fprintf_filtered (gdb_stdlog,
430 "Detaching after fork from "
431 "child process %d.\n",
435 old_chain = save_inferior_ptid ();
436 inferior_ptid = ptid_build (child_pid, child_pid, 0);
438 child_lp = add_lwp (inferior_ptid);
439 child_lp->stopped = 1;
440 child_lp->last_resume_kind = resume_stop;
441 make_cleanup (delete_lwp_cleanup, child_lp);
443 if (linux_nat_prepare_to_resume != NULL)
444 linux_nat_prepare_to_resume (child_lp);
445 ptrace (PTRACE_DETACH, child_pid, 0, 0);
447 do_cleanups (old_chain);
451 struct inferior *parent_inf, *child_inf;
452 struct cleanup *old_chain;
454 /* Add process to GDB's tables. */
455 child_inf = add_inferior (child_pid);
457 parent_inf = current_inferior ();
458 child_inf->attach_flag = parent_inf->attach_flag;
459 copy_terminal_info (child_inf, parent_inf);
460 child_inf->gdbarch = parent_inf->gdbarch;
461 copy_inferior_target_desc_info (child_inf, parent_inf);
463 old_chain = save_inferior_ptid ();
464 save_current_program_space ();
466 inferior_ptid = ptid_build (child_pid, child_pid, 0);
467 add_thread (inferior_ptid);
468 child_lp = add_lwp (inferior_ptid);
469 child_lp->stopped = 1;
470 child_lp->last_resume_kind = resume_stop;
471 child_inf->symfile_flags = SYMFILE_NO_READ;
473 /* If this is a vfork child, then the address-space is
474 shared with the parent. */
477 child_inf->pspace = parent_inf->pspace;
478 child_inf->aspace = parent_inf->aspace;
480 /* The parent will be frozen until the child is done
481 with the shared region. Keep track of the
483 child_inf->vfork_parent = parent_inf;
484 child_inf->pending_detach = 0;
485 parent_inf->vfork_child = child_inf;
486 parent_inf->pending_detach = 0;
490 child_inf->aspace = new_address_space ();
491 child_inf->pspace = add_program_space (child_inf->aspace);
492 child_inf->removable = 1;
493 set_current_program_space (child_inf->pspace);
494 clone_program_space (child_inf->pspace, parent_inf->pspace);
496 /* Let the shared library layer (solib-svr4) learn about
497 this new process, relocate the cloned exec, pull in
498 shared libraries, and install the solib event
499 breakpoint. If a "cloned-VM" event was propagated
500 better throughout the core, this wouldn't be
502 solib_create_inferior_hook (0);
505 /* Let the thread_db layer learn about this new process. */
506 check_for_thread_db ();
508 do_cleanups (old_chain);
513 struct lwp_info *parent_lp;
514 struct inferior *parent_inf;
516 parent_inf = current_inferior ();
518 /* If we detached from the child, then we have to be careful
519 to not insert breakpoints in the parent until the child
520 is done with the shared memory region. However, if we're
521 staying attached to the child, then we can and should
522 insert breakpoints, so that we can debug it. A
523 subsequent child exec or exit is enough to know when does
524 the child stops using the parent's address space. */
525 parent_inf->waiting_for_vfork_done = detach_fork;
526 parent_inf->pspace->breakpoints_not_allowed = detach_fork;
528 parent_lp = find_lwp_pid (pid_to_ptid (parent_pid));
529 gdb_assert (linux_supports_tracefork () >= 0);
531 if (linux_supports_tracevforkdone ())
534 fprintf_unfiltered (gdb_stdlog,
535 "LCFF: waiting for VFORK_DONE on %d\n",
537 parent_lp->stopped = 1;
539 /* We'll handle the VFORK_DONE event like any other
540 event, in target_wait. */
544 /* We can't insert breakpoints until the child has
545 finished with the shared memory region. We need to
546 wait until that happens. Ideal would be to just
548 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
549 - waitpid (parent_pid, &status, __WALL);
550 However, most architectures can't handle a syscall
551 being traced on the way out if it wasn't traced on
554 We might also think to loop, continuing the child
555 until it exits or gets a SIGTRAP. One problem is
556 that the child might call ptrace with PTRACE_TRACEME.
558 There's no simple and reliable way to figure out when
559 the vforked child will be done with its copy of the
560 shared memory. We could step it out of the syscall,
561 two instructions, let it go, and then single-step the
562 parent once. When we have hardware single-step, this
563 would work; with software single-step it could still
564 be made to work but we'd have to be able to insert
565 single-step breakpoints in the child, and we'd have
566 to insert -just- the single-step breakpoint in the
567 parent. Very awkward.
569 In the end, the best we can do is to make sure it
570 runs for a little while. Hopefully it will be out of
571 range of any breakpoints we reinsert. Usually this
572 is only the single-step breakpoint at vfork's return
576 fprintf_unfiltered (gdb_stdlog,
577 "LCFF: no VFORK_DONE "
578 "support, sleeping a bit\n");
582 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
583 and leave it pending. The next linux_nat_resume call
584 will notice a pending event, and bypasses actually
585 resuming the inferior. */
586 parent_lp->status = 0;
587 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
588 parent_lp->stopped = 1;
590 /* If we're in async mode, need to tell the event loop
591 there's something here to process. */
592 if (target_can_async_p ())
599 struct inferior *parent_inf, *child_inf;
600 struct lwp_info *child_lp;
601 struct program_space *parent_pspace;
603 if (info_verbose || debug_linux_nat)
605 target_terminal_ours ();
607 fprintf_filtered (gdb_stdlog,
608 _("Attaching after process %d "
609 "vfork to child process %d.\n"),
610 parent_pid, child_pid);
612 fprintf_filtered (gdb_stdlog,
613 _("Attaching after process %d "
614 "fork to child process %d.\n"),
615 parent_pid, child_pid);
618 /* Add the new inferior first, so that the target_detach below
619 doesn't unpush the target. */
621 child_inf = add_inferior (child_pid);
623 parent_inf = current_inferior ();
624 child_inf->attach_flag = parent_inf->attach_flag;
625 copy_terminal_info (child_inf, parent_inf);
626 child_inf->gdbarch = parent_inf->gdbarch;
627 copy_inferior_target_desc_info (child_inf, parent_inf);
629 parent_pspace = parent_inf->pspace;
631 /* If we're vforking, we want to hold on to the parent until the
632 child exits or execs. At child exec or exit time we can
633 remove the old breakpoints from the parent and detach or
634 resume debugging it. Otherwise, detach the parent now; we'll
635 want to reuse it's program/address spaces, but we can't set
636 them to the child before removing breakpoints from the
637 parent, otherwise, the breakpoints module could decide to
638 remove breakpoints from the wrong process (since they'd be
639 assigned to the same address space). */
643 gdb_assert (child_inf->vfork_parent == NULL);
644 gdb_assert (parent_inf->vfork_child == NULL);
645 child_inf->vfork_parent = parent_inf;
646 child_inf->pending_detach = 0;
647 parent_inf->vfork_child = child_inf;
648 parent_inf->pending_detach = detach_fork;
649 parent_inf->waiting_for_vfork_done = 0;
651 else if (detach_fork)
652 target_detach (NULL, 0);
654 /* Note that the detach above makes PARENT_INF dangling. */
656 /* Add the child thread to the appropriate lists, and switch to
657 this new thread, before cloning the program space, and
658 informing the solib layer about this new process. */
660 inferior_ptid = ptid_build (child_pid, child_pid, 0);
661 add_thread (inferior_ptid);
662 child_lp = add_lwp (inferior_ptid);
663 child_lp->stopped = 1;
664 child_lp->last_resume_kind = resume_stop;
666 /* If this is a vfork child, then the address-space is shared
667 with the parent. If we detached from the parent, then we can
668 reuse the parent's program/address spaces. */
669 if (has_vforked || detach_fork)
671 child_inf->pspace = parent_pspace;
672 child_inf->aspace = child_inf->pspace->aspace;
676 child_inf->aspace = new_address_space ();
677 child_inf->pspace = add_program_space (child_inf->aspace);
678 child_inf->removable = 1;
679 child_inf->symfile_flags = SYMFILE_NO_READ;
680 set_current_program_space (child_inf->pspace);
681 clone_program_space (child_inf->pspace, parent_pspace);
683 /* Let the shared library layer (solib-svr4) learn about
684 this new process, relocate the cloned exec, pull in
685 shared libraries, and install the solib event breakpoint.
686 If a "cloned-VM" event was propagated better throughout
687 the core, this wouldn't be required. */
688 solib_create_inferior_hook (0);
691 /* Let the thread_db layer learn about this new process. */
692 check_for_thread_db ();
700 linux_child_insert_fork_catchpoint (struct target_ops *self, int pid)
702 return !linux_supports_tracefork ();
706 linux_child_remove_fork_catchpoint (struct target_ops *self, int pid)
712 linux_child_insert_vfork_catchpoint (struct target_ops *self, int pid)
714 return !linux_supports_tracefork ();
718 linux_child_remove_vfork_catchpoint (struct target_ops *self, int pid)
724 linux_child_insert_exec_catchpoint (struct target_ops *self, int pid)
726 return !linux_supports_tracefork ();
730 linux_child_remove_exec_catchpoint (struct target_ops *self, int pid)
736 linux_child_set_syscall_catchpoint (struct target_ops *self,
737 int pid, int needed, int any_count,
738 int table_size, int *table)
740 if (!linux_supports_tracesysgood ())
743 /* On GNU/Linux, we ignore the arguments. It means that we only
744 enable the syscall catchpoints, but do not disable them.
746 Also, we do not use the `table' information because we do not
747 filter system calls here. We let GDB do the logic for us. */
751 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
752 are processes sharing the same VM space. A multi-threaded process
753 is basically a group of such processes. However, such a grouping
754 is almost entirely a user-space issue; the kernel doesn't enforce
755 such a grouping at all (this might change in the future). In
756 general, we'll rely on the threads library (i.e. the GNU/Linux
757 Threads library) to provide such a grouping.
759 It is perfectly well possible to write a multi-threaded application
760 without the assistance of a threads library, by using the clone
761 system call directly. This module should be able to give some
762 rudimentary support for debugging such applications if developers
763 specify the CLONE_PTRACE flag in the clone system call, and are
764 using the Linux kernel 2.4 or above.
766 Note that there are some peculiarities in GNU/Linux that affect
769 - In general one should specify the __WCLONE flag to waitpid in
770 order to make it report events for any of the cloned processes
771 (and leave it out for the initial process). However, if a cloned
772 process has exited the exit status is only reported if the
773 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
774 we cannot use it since GDB must work on older systems too.
776 - When a traced, cloned process exits and is waited for by the
777 debugger, the kernel reassigns it to the original parent and
778 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
779 library doesn't notice this, which leads to the "zombie problem":
780 When debugged a multi-threaded process that spawns a lot of
781 threads will run out of processes, even if the threads exit,
782 because the "zombies" stay around. */
784 /* List of known LWPs. */
785 struct lwp_info *lwp_list;
788 /* Original signal mask. */
789 static sigset_t normal_mask;
791 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
792 _initialize_linux_nat. */
793 static sigset_t suspend_mask;
795 /* Signals to block to make that sigsuspend work. */
796 static sigset_t blocked_mask;
798 /* SIGCHLD action. */
799 struct sigaction sigchld_action;
801 /* Block child signals (SIGCHLD and linux threads signals), and store
802 the previous mask in PREV_MASK. */
805 block_child_signals (sigset_t *prev_mask)
807 /* Make sure SIGCHLD is blocked. */
808 if (!sigismember (&blocked_mask, SIGCHLD))
809 sigaddset (&blocked_mask, SIGCHLD);
811 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
814 /* Restore child signals mask, previously returned by
815 block_child_signals. */
818 restore_child_signals_mask (sigset_t *prev_mask)
820 sigprocmask (SIG_SETMASK, prev_mask, NULL);
823 /* Mask of signals to pass directly to the inferior. */
824 static sigset_t pass_mask;
826 /* Update signals to pass to the inferior. */
828 linux_nat_pass_signals (struct target_ops *self,
829 int numsigs, unsigned char *pass_signals)
833 sigemptyset (&pass_mask);
835 for (signo = 1; signo < NSIG; signo++)
837 int target_signo = gdb_signal_from_host (signo);
838 if (target_signo < numsigs && pass_signals[target_signo])
839 sigaddset (&pass_mask, signo);
845 /* Prototypes for local functions. */
846 static int stop_wait_callback (struct lwp_info *lp, void *data);
847 static int linux_thread_alive (ptid_t ptid);
848 static char *linux_child_pid_to_exec_file (struct target_ops *self, int pid);
852 /* Destroy and free LP. */
855 lwp_free (struct lwp_info *lp)
857 xfree (lp->arch_private);
861 /* Remove all LWPs belong to PID from the lwp list. */
864 purge_lwp_list (int pid)
866 struct lwp_info *lp, *lpprev, *lpnext;
870 for (lp = lwp_list; lp; lp = lpnext)
874 if (ptid_get_pid (lp->ptid) == pid)
879 lpprev->next = lp->next;
888 /* Add the LWP specified by PTID to the list. PTID is the first LWP
889 in the process. Return a pointer to the structure describing the
892 This differs from add_lwp in that we don't let the arch specific
893 bits know about this new thread. Current clients of this callback
894 take the opportunity to install watchpoints in the new thread, and
895 we shouldn't do that for the first thread. If we're spawning a
896 child ("run"), the thread executes the shell wrapper first, and we
897 shouldn't touch it until it execs the program we want to debug.
898 For "attach", it'd be okay to call the callback, but it's not
899 necessary, because watchpoints can't yet have been inserted into
902 static struct lwp_info *
903 add_initial_lwp (ptid_t ptid)
907 gdb_assert (ptid_lwp_p (ptid));
909 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
911 memset (lp, 0, sizeof (struct lwp_info));
913 lp->last_resume_kind = resume_continue;
914 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
925 /* Add the LWP specified by PID to the list. Return a pointer to the
926 structure describing the new LWP. The LWP should already be
929 static struct lwp_info *
930 add_lwp (ptid_t ptid)
934 lp = add_initial_lwp (ptid);
936 /* Let the arch specific bits know about this new thread. Current
937 clients of this callback take the opportunity to install
938 watchpoints in the new thread. We don't do this for the first
939 thread though. See add_initial_lwp. */
940 if (linux_nat_new_thread != NULL)
941 linux_nat_new_thread (lp);
946 /* Remove the LWP specified by PID from the list. */
949 delete_lwp (ptid_t ptid)
951 struct lwp_info *lp, *lpprev;
955 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
956 if (ptid_equal (lp->ptid, ptid))
963 lpprev->next = lp->next;
970 /* Return a pointer to the structure describing the LWP corresponding
971 to PID. If no corresponding LWP could be found, return NULL. */
973 static struct lwp_info *
974 find_lwp_pid (ptid_t ptid)
979 if (ptid_lwp_p (ptid))
980 lwp = ptid_get_lwp (ptid);
982 lwp = ptid_get_pid (ptid);
984 for (lp = lwp_list; lp; lp = lp->next)
985 if (lwp == ptid_get_lwp (lp->ptid))
991 /* Call CALLBACK with its second argument set to DATA for every LWP in
992 the list. If CALLBACK returns 1 for a particular LWP, return a
993 pointer to the structure describing that LWP immediately.
994 Otherwise return NULL. */
997 iterate_over_lwps (ptid_t filter,
998 int (*callback) (struct lwp_info *, void *),
1001 struct lwp_info *lp, *lpnext;
1003 for (lp = lwp_list; lp; lp = lpnext)
1007 if (ptid_match (lp->ptid, filter))
1009 if ((*callback) (lp, data))
1017 /* Update our internal state when changing from one checkpoint to
1018 another indicated by NEW_PTID. We can only switch single-threaded
1019 applications, so we only create one new LWP, and the previous list
1023 linux_nat_switch_fork (ptid_t new_ptid)
1025 struct lwp_info *lp;
1027 purge_lwp_list (ptid_get_pid (inferior_ptid));
1029 lp = add_lwp (new_ptid);
1032 /* This changes the thread's ptid while preserving the gdb thread
1033 num. Also changes the inferior pid, while preserving the
1035 thread_change_ptid (inferior_ptid, new_ptid);
1037 /* We've just told GDB core that the thread changed target id, but,
1038 in fact, it really is a different thread, with different register
1040 registers_changed ();
1043 /* Handle the exit of a single thread LP. */
1046 exit_lwp (struct lwp_info *lp)
1048 struct thread_info *th = find_thread_ptid (lp->ptid);
1052 if (print_thread_events)
1053 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
1055 delete_thread (lp->ptid);
1058 delete_lwp (lp->ptid);
1061 /* Wait for the LWP specified by LP, which we have just attached to.
1062 Returns a wait status for that LWP, to cache. */
1065 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
1068 pid_t new_pid, pid = ptid_get_lwp (ptid);
1071 if (linux_proc_pid_is_stopped (pid))
1073 if (debug_linux_nat)
1074 fprintf_unfiltered (gdb_stdlog,
1075 "LNPAW: Attaching to a stopped process\n");
1077 /* The process is definitely stopped. It is in a job control
1078 stop, unless the kernel predates the TASK_STOPPED /
1079 TASK_TRACED distinction, in which case it might be in a
1080 ptrace stop. Make sure it is in a ptrace stop; from there we
1081 can kill it, signal it, et cetera.
1083 First make sure there is a pending SIGSTOP. Since we are
1084 already attached, the process can not transition from stopped
1085 to running without a PTRACE_CONT; so we know this signal will
1086 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1087 probably already in the queue (unless this kernel is old
1088 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1089 is not an RT signal, it can only be queued once. */
1090 kill_lwp (pid, SIGSTOP);
1092 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1093 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1094 ptrace (PTRACE_CONT, pid, 0, 0);
1097 /* Make sure the initial process is stopped. The user-level threads
1098 layer might want to poke around in the inferior, and that won't
1099 work if things haven't stabilized yet. */
1100 new_pid = my_waitpid (pid, &status, 0);
1101 if (new_pid == -1 && errno == ECHILD)
1104 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
1106 /* Try again with __WCLONE to check cloned processes. */
1107 new_pid = my_waitpid (pid, &status, __WCLONE);
1111 gdb_assert (pid == new_pid);
1113 if (!WIFSTOPPED (status))
1115 /* The pid we tried to attach has apparently just exited. */
1116 if (debug_linux_nat)
1117 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
1118 pid, status_to_str (status));
1122 if (WSTOPSIG (status) != SIGSTOP)
1125 if (debug_linux_nat)
1126 fprintf_unfiltered (gdb_stdlog,
1127 "LNPAW: Received %s after attaching\n",
1128 status_to_str (status));
1134 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1135 the new LWP could not be attached, or 1 if we're already auto
1136 attached to this thread, but haven't processed the
1137 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1138 its existance, without considering it an error. */
1141 lin_lwp_attach_lwp (ptid_t ptid)
1143 struct lwp_info *lp;
1146 gdb_assert (ptid_lwp_p (ptid));
1148 lp = find_lwp_pid (ptid);
1149 lwpid = ptid_get_lwp (ptid);
1151 /* We assume that we're already attached to any LWP that has an id
1152 equal to the overall process id, and to any LWP that is already
1153 in our list of LWPs. If we're not seeing exit events from threads
1154 and we've had PID wraparound since we last tried to stop all threads,
1155 this assumption might be wrong; fortunately, this is very unlikely
1157 if (lwpid != ptid_get_pid (ptid) && lp == NULL)
1159 int status, cloned = 0, signalled = 0;
1161 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1163 if (linux_supports_tracefork ())
1165 /* If we haven't stopped all threads when we get here,
1166 we may have seen a thread listed in thread_db's list,
1167 but not processed the PTRACE_EVENT_CLONE yet. If
1168 that's the case, ignore this new thread, and let
1169 normal event handling discover it later. */
1170 if (in_pid_list_p (stopped_pids, lwpid))
1172 /* We've already seen this thread stop, but we
1173 haven't seen the PTRACE_EVENT_CLONE extended
1182 /* See if we've got a stop for this new child
1183 pending. If so, we're already attached. */
1184 new_pid = my_waitpid (lwpid, &status, WNOHANG);
1185 if (new_pid == -1 && errno == ECHILD)
1186 new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
1189 if (WIFSTOPPED (status))
1190 add_to_pid_list (&stopped_pids, lwpid, status);
1196 /* If we fail to attach to the thread, issue a warning,
1197 but continue. One way this can happen is if thread
1198 creation is interrupted; as of Linux kernel 2.6.19, a
1199 bug may place threads in the thread list and then fail
1201 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1202 safe_strerror (errno));
1206 if (debug_linux_nat)
1207 fprintf_unfiltered (gdb_stdlog,
1208 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1209 target_pid_to_str (ptid));
1211 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1212 if (!WIFSTOPPED (status))
1215 lp = add_lwp (ptid);
1217 lp->cloned = cloned;
1218 lp->signalled = signalled;
1219 if (WSTOPSIG (status) != SIGSTOP)
1222 lp->status = status;
1225 target_post_attach (ptid_get_lwp (lp->ptid));
1227 if (debug_linux_nat)
1229 fprintf_unfiltered (gdb_stdlog,
1230 "LLAL: waitpid %s received %s\n",
1231 target_pid_to_str (ptid),
1232 status_to_str (status));
1237 /* We assume that the LWP representing the original process is
1238 already stopped. Mark it as stopped in the data structure
1239 that the GNU/linux ptrace layer uses to keep track of
1240 threads. Note that this won't have already been done since
1241 the main thread will have, we assume, been stopped by an
1242 attach from a different layer. */
1244 lp = add_lwp (ptid);
1248 lp->last_resume_kind = resume_stop;
1253 linux_nat_create_inferior (struct target_ops *ops,
1254 char *exec_file, char *allargs, char **env,
1257 #ifdef HAVE_PERSONALITY
1258 int personality_orig = 0, personality_set = 0;
1259 #endif /* HAVE_PERSONALITY */
1261 /* The fork_child mechanism is synchronous and calls target_wait, so
1262 we have to mask the async mode. */
1264 #ifdef HAVE_PERSONALITY
1265 if (disable_randomization)
1268 personality_orig = personality (0xffffffff);
1269 if (errno == 0 && !(personality_orig & ADDR_NO_RANDOMIZE))
1271 personality_set = 1;
1272 personality (personality_orig | ADDR_NO_RANDOMIZE);
1274 if (errno != 0 || (personality_set
1275 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE)))
1276 warning (_("Error disabling address space randomization: %s"),
1277 safe_strerror (errno));
1279 #endif /* HAVE_PERSONALITY */
1281 /* Make sure we report all signals during startup. */
1282 linux_nat_pass_signals (ops, 0, NULL);
1284 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1286 #ifdef HAVE_PERSONALITY
1287 if (personality_set)
1290 personality (personality_orig);
1292 warning (_("Error restoring address space randomization: %s"),
1293 safe_strerror (errno));
1295 #endif /* HAVE_PERSONALITY */
1299 linux_nat_attach (struct target_ops *ops, char *args, int from_tty)
1301 struct lwp_info *lp;
1304 volatile struct gdb_exception ex;
1306 /* Make sure we report all signals during attach. */
1307 linux_nat_pass_signals (ops, 0, NULL);
1309 TRY_CATCH (ex, RETURN_MASK_ERROR)
1311 linux_ops->to_attach (ops, args, from_tty);
1315 pid_t pid = parse_pid_to_attach (args);
1316 struct buffer buffer;
1317 char *message, *buffer_s;
1319 message = xstrdup (ex.message);
1320 make_cleanup (xfree, message);
1322 buffer_init (&buffer);
1323 linux_ptrace_attach_warnings (pid, &buffer);
1325 buffer_grow_str0 (&buffer, "");
1326 buffer_s = buffer_finish (&buffer);
1327 make_cleanup (xfree, buffer_s);
1329 throw_error (ex.error, "%s%s", buffer_s, message);
1332 /* The ptrace base target adds the main thread with (pid,0,0)
1333 format. Decorate it with lwp info. */
1334 ptid = ptid_build (ptid_get_pid (inferior_ptid),
1335 ptid_get_pid (inferior_ptid),
1337 thread_change_ptid (inferior_ptid, ptid);
1339 /* Add the initial process as the first LWP to the list. */
1340 lp = add_initial_lwp (ptid);
1342 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1344 if (!WIFSTOPPED (status))
1346 if (WIFEXITED (status))
1348 int exit_code = WEXITSTATUS (status);
1350 target_terminal_ours ();
1351 target_mourn_inferior ();
1353 error (_("Unable to attach: program exited normally."));
1355 error (_("Unable to attach: program exited with code %d."),
1358 else if (WIFSIGNALED (status))
1360 enum gdb_signal signo;
1362 target_terminal_ours ();
1363 target_mourn_inferior ();
1365 signo = gdb_signal_from_host (WTERMSIG (status));
1366 error (_("Unable to attach: program terminated with signal "
1368 gdb_signal_to_name (signo),
1369 gdb_signal_to_string (signo));
1372 internal_error (__FILE__, __LINE__,
1373 _("unexpected status %d for PID %ld"),
1374 status, (long) ptid_get_lwp (ptid));
1379 /* Save the wait status to report later. */
1381 if (debug_linux_nat)
1382 fprintf_unfiltered (gdb_stdlog,
1383 "LNA: waitpid %ld, saving status %s\n",
1384 (long) ptid_get_pid (lp->ptid), status_to_str (status));
1386 lp->status = status;
1388 if (target_can_async_p ())
1389 target_async (inferior_event_handler, 0);
1392 /* Get pending status of LP. */
1394 get_pending_status (struct lwp_info *lp, int *status)
1396 enum gdb_signal signo = GDB_SIGNAL_0;
1398 /* If we paused threads momentarily, we may have stored pending
1399 events in lp->status or lp->waitstatus (see stop_wait_callback),
1400 and GDB core hasn't seen any signal for those threads.
1401 Otherwise, the last signal reported to the core is found in the
1402 thread object's stop_signal.
1404 There's a corner case that isn't handled here at present. Only
1405 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1406 stop_signal make sense as a real signal to pass to the inferior.
1407 Some catchpoint related events, like
1408 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1409 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1410 those traps are debug API (ptrace in our case) related and
1411 induced; the inferior wouldn't see them if it wasn't being
1412 traced. Hence, we should never pass them to the inferior, even
1413 when set to pass state. Since this corner case isn't handled by
1414 infrun.c when proceeding with a signal, for consistency, neither
1415 do we handle it here (or elsewhere in the file we check for
1416 signal pass state). Normally SIGTRAP isn't set to pass state, so
1417 this is really a corner case. */
1419 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1420 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1421 else if (lp->status)
1422 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1423 else if (non_stop && !is_executing (lp->ptid))
1425 struct thread_info *tp = find_thread_ptid (lp->ptid);
1427 signo = tp->suspend.stop_signal;
1431 struct target_waitstatus last;
1434 get_last_target_status (&last_ptid, &last);
1436 if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
1438 struct thread_info *tp = find_thread_ptid (lp->ptid);
1440 signo = tp->suspend.stop_signal;
1446 if (signo == GDB_SIGNAL_0)
1448 if (debug_linux_nat)
1449 fprintf_unfiltered (gdb_stdlog,
1450 "GPT: lwp %s has no pending signal\n",
1451 target_pid_to_str (lp->ptid));
1453 else if (!signal_pass_state (signo))
1455 if (debug_linux_nat)
1456 fprintf_unfiltered (gdb_stdlog,
1457 "GPT: lwp %s had signal %s, "
1458 "but it is in no pass state\n",
1459 target_pid_to_str (lp->ptid),
1460 gdb_signal_to_string (signo));
1464 *status = W_STOPCODE (gdb_signal_to_host (signo));
1466 if (debug_linux_nat)
1467 fprintf_unfiltered (gdb_stdlog,
1468 "GPT: lwp %s has pending signal %s\n",
1469 target_pid_to_str (lp->ptid),
1470 gdb_signal_to_string (signo));
1477 detach_callback (struct lwp_info *lp, void *data)
1479 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1481 if (debug_linux_nat && lp->status)
1482 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1483 strsignal (WSTOPSIG (lp->status)),
1484 target_pid_to_str (lp->ptid));
1486 /* If there is a pending SIGSTOP, get rid of it. */
1489 if (debug_linux_nat)
1490 fprintf_unfiltered (gdb_stdlog,
1491 "DC: Sending SIGCONT to %s\n",
1492 target_pid_to_str (lp->ptid));
1494 kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
1498 /* We don't actually detach from the LWP that has an id equal to the
1499 overall process id just yet. */
1500 if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
1504 /* Pass on any pending signal for this LWP. */
1505 get_pending_status (lp, &status);
1507 if (linux_nat_prepare_to_resume != NULL)
1508 linux_nat_prepare_to_resume (lp);
1510 if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
1511 WSTOPSIG (status)) < 0)
1512 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1513 safe_strerror (errno));
1515 if (debug_linux_nat)
1516 fprintf_unfiltered (gdb_stdlog,
1517 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1518 target_pid_to_str (lp->ptid),
1519 strsignal (WSTOPSIG (status)));
1521 delete_lwp (lp->ptid);
1528 linux_nat_detach (struct target_ops *ops, const char *args, int from_tty)
1532 struct lwp_info *main_lwp;
1534 pid = ptid_get_pid (inferior_ptid);
1536 /* Don't unregister from the event loop, as there may be other
1537 inferiors running. */
1539 /* Stop all threads before detaching. ptrace requires that the
1540 thread is stopped to sucessfully detach. */
1541 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1542 /* ... and wait until all of them have reported back that
1543 they're no longer running. */
1544 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1546 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1548 /* Only the initial process should be left right now. */
1549 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
1551 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1553 /* Pass on any pending signal for the last LWP. */
1554 if ((args == NULL || *args == '\0')
1555 && get_pending_status (main_lwp, &status) != -1
1556 && WIFSTOPPED (status))
1560 /* Put the signal number in ARGS so that inf_ptrace_detach will
1561 pass it along with PTRACE_DETACH. */
1563 xsnprintf (tem, 8, "%d", (int) WSTOPSIG (status));
1565 if (debug_linux_nat)
1566 fprintf_unfiltered (gdb_stdlog,
1567 "LND: Sending signal %s to %s\n",
1569 target_pid_to_str (main_lwp->ptid));
1572 if (linux_nat_prepare_to_resume != NULL)
1573 linux_nat_prepare_to_resume (main_lwp);
1574 delete_lwp (main_lwp->ptid);
1576 if (forks_exist_p ())
1578 /* Multi-fork case. The current inferior_ptid is being detached
1579 from, but there are other viable forks to debug. Detach from
1580 the current fork, and context-switch to the first
1582 linux_fork_detach (args, from_tty);
1585 linux_ops->to_detach (ops, args, from_tty);
1591 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1595 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
1597 if (inf->vfork_child != NULL)
1599 if (debug_linux_nat)
1600 fprintf_unfiltered (gdb_stdlog,
1601 "RC: Not resuming %s (vfork parent)\n",
1602 target_pid_to_str (lp->ptid));
1604 else if (lp->status == 0
1605 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
1607 if (debug_linux_nat)
1608 fprintf_unfiltered (gdb_stdlog,
1609 "RC: Resuming sibling %s, %s, %s\n",
1610 target_pid_to_str (lp->ptid),
1611 (signo != GDB_SIGNAL_0
1612 ? strsignal (gdb_signal_to_host (signo))
1614 step ? "step" : "resume");
1616 if (linux_nat_prepare_to_resume != NULL)
1617 linux_nat_prepare_to_resume (lp);
1618 linux_ops->to_resume (linux_ops,
1619 pid_to_ptid (ptid_get_lwp (lp->ptid)),
1623 lp->stopped_by_watchpoint = 0;
1627 if (debug_linux_nat)
1628 fprintf_unfiltered (gdb_stdlog,
1629 "RC: Not resuming sibling %s (has pending)\n",
1630 target_pid_to_str (lp->ptid));
1635 if (debug_linux_nat)
1636 fprintf_unfiltered (gdb_stdlog,
1637 "RC: Not resuming sibling %s (not stopped)\n",
1638 target_pid_to_str (lp->ptid));
1642 /* Resume LWP, with the last stop signal, if it is in pass state. */
1645 linux_nat_resume_callback (struct lwp_info *lp, void *data)
1647 enum gdb_signal signo = GDB_SIGNAL_0;
1651 struct thread_info *thread;
1653 thread = find_thread_ptid (lp->ptid);
1656 if (signal_pass_state (thread->suspend.stop_signal))
1657 signo = thread->suspend.stop_signal;
1658 thread->suspend.stop_signal = GDB_SIGNAL_0;
1662 resume_lwp (lp, 0, signo);
1667 resume_clear_callback (struct lwp_info *lp, void *data)
1670 lp->last_resume_kind = resume_stop;
1675 resume_set_callback (struct lwp_info *lp, void *data)
1678 lp->last_resume_kind = resume_continue;
1683 linux_nat_resume (struct target_ops *ops,
1684 ptid_t ptid, int step, enum gdb_signal signo)
1686 struct lwp_info *lp;
1689 if (debug_linux_nat)
1690 fprintf_unfiltered (gdb_stdlog,
1691 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1692 step ? "step" : "resume",
1693 target_pid_to_str (ptid),
1694 (signo != GDB_SIGNAL_0
1695 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1696 target_pid_to_str (inferior_ptid));
1698 /* A specific PTID means `step only this process id'. */
1699 resume_many = (ptid_equal (minus_one_ptid, ptid)
1700 || ptid_is_pid (ptid));
1702 /* Mark the lwps we're resuming as resumed. */
1703 iterate_over_lwps (ptid, resume_set_callback, NULL);
1705 /* See if it's the current inferior that should be handled
1708 lp = find_lwp_pid (inferior_ptid);
1710 lp = find_lwp_pid (ptid);
1711 gdb_assert (lp != NULL);
1713 /* Remember if we're stepping. */
1715 lp->last_resume_kind = step ? resume_step : resume_continue;
1717 /* If we have a pending wait status for this thread, there is no
1718 point in resuming the process. But first make sure that
1719 linux_nat_wait won't preemptively handle the event - we
1720 should never take this short-circuit if we are going to
1721 leave LP running, since we have skipped resuming all the
1722 other threads. This bit of code needs to be synchronized
1723 with linux_nat_wait. */
1725 if (lp->status && WIFSTOPPED (lp->status))
1728 && WSTOPSIG (lp->status)
1729 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1731 if (debug_linux_nat)
1732 fprintf_unfiltered (gdb_stdlog,
1733 "LLR: Not short circuiting for ignored "
1734 "status 0x%x\n", lp->status);
1736 /* FIXME: What should we do if we are supposed to continue
1737 this thread with a signal? */
1738 gdb_assert (signo == GDB_SIGNAL_0);
1739 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1744 if (lp->status || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1746 /* FIXME: What should we do if we are supposed to continue
1747 this thread with a signal? */
1748 gdb_assert (signo == GDB_SIGNAL_0);
1750 if (debug_linux_nat)
1751 fprintf_unfiltered (gdb_stdlog,
1752 "LLR: Short circuiting for status 0x%x\n",
1755 if (target_can_async_p ())
1757 target_async (inferior_event_handler, 0);
1758 /* Tell the event loop we have something to process. */
1764 /* Mark LWP as not stopped to prevent it from being continued by
1765 linux_nat_resume_callback. */
1769 iterate_over_lwps (ptid, linux_nat_resume_callback, NULL);
1771 /* Convert to something the lower layer understands. */
1772 ptid = pid_to_ptid (ptid_get_lwp (lp->ptid));
1774 if (linux_nat_prepare_to_resume != NULL)
1775 linux_nat_prepare_to_resume (lp);
1776 linux_ops->to_resume (linux_ops, ptid, step, signo);
1777 lp->stopped_by_watchpoint = 0;
1779 if (debug_linux_nat)
1780 fprintf_unfiltered (gdb_stdlog,
1781 "LLR: %s %s, %s (resume event thread)\n",
1782 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1783 target_pid_to_str (ptid),
1784 (signo != GDB_SIGNAL_0
1785 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1787 if (target_can_async_p ())
1788 target_async (inferior_event_handler, 0);
1791 /* Send a signal to an LWP. */
1794 kill_lwp (int lwpid, int signo)
1796 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1797 fails, then we are not using nptl threads and we should be using kill. */
1799 #ifdef HAVE_TKILL_SYSCALL
1801 static int tkill_failed;
1808 ret = syscall (__NR_tkill, lwpid, signo);
1809 if (errno != ENOSYS)
1816 return kill (lwpid, signo);
1819 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1820 event, check if the core is interested in it: if not, ignore the
1821 event, and keep waiting; otherwise, we need to toggle the LWP's
1822 syscall entry/exit status, since the ptrace event itself doesn't
1823 indicate it, and report the trap to higher layers. */
1826 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1828 struct target_waitstatus *ourstatus = &lp->waitstatus;
1829 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1830 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1834 /* If we're stopping threads, there's a SIGSTOP pending, which
1835 makes it so that the LWP reports an immediate syscall return,
1836 followed by the SIGSTOP. Skip seeing that "return" using
1837 PTRACE_CONT directly, and let stop_wait_callback collect the
1838 SIGSTOP. Later when the thread is resumed, a new syscall
1839 entry event. If we didn't do this (and returned 0), we'd
1840 leave a syscall entry pending, and our caller, by using
1841 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1842 itself. Later, when the user re-resumes this LWP, we'd see
1843 another syscall entry event and we'd mistake it for a return.
1845 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1846 (leaving immediately with LWP->signalled set, without issuing
1847 a PTRACE_CONT), it would still be problematic to leave this
1848 syscall enter pending, as later when the thread is resumed,
1849 it would then see the same syscall exit mentioned above,
1850 followed by the delayed SIGSTOP, while the syscall didn't
1851 actually get to execute. It seems it would be even more
1852 confusing to the user. */
1854 if (debug_linux_nat)
1855 fprintf_unfiltered (gdb_stdlog,
1856 "LHST: ignoring syscall %d "
1857 "for LWP %ld (stopping threads), "
1858 "resuming with PTRACE_CONT for SIGSTOP\n",
1860 ptid_get_lwp (lp->ptid));
1862 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1863 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1867 if (catch_syscall_enabled ())
1869 /* Always update the entry/return state, even if this particular
1870 syscall isn't interesting to the core now. In async mode,
1871 the user could install a new catchpoint for this syscall
1872 between syscall enter/return, and we'll need to know to
1873 report a syscall return if that happens. */
1874 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1875 ? TARGET_WAITKIND_SYSCALL_RETURN
1876 : TARGET_WAITKIND_SYSCALL_ENTRY);
1878 if (catching_syscall_number (syscall_number))
1880 /* Alright, an event to report. */
1881 ourstatus->kind = lp->syscall_state;
1882 ourstatus->value.syscall_number = syscall_number;
1884 if (debug_linux_nat)
1885 fprintf_unfiltered (gdb_stdlog,
1886 "LHST: stopping for %s of syscall %d"
1889 == TARGET_WAITKIND_SYSCALL_ENTRY
1890 ? "entry" : "return",
1892 ptid_get_lwp (lp->ptid));
1896 if (debug_linux_nat)
1897 fprintf_unfiltered (gdb_stdlog,
1898 "LHST: ignoring %s of syscall %d "
1900 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1901 ? "entry" : "return",
1903 ptid_get_lwp (lp->ptid));
1907 /* If we had been syscall tracing, and hence used PT_SYSCALL
1908 before on this LWP, it could happen that the user removes all
1909 syscall catchpoints before we get to process this event.
1910 There are two noteworthy issues here:
1912 - When stopped at a syscall entry event, resuming with
1913 PT_STEP still resumes executing the syscall and reports a
1916 - Only PT_SYSCALL catches syscall enters. If we last
1917 single-stepped this thread, then this event can't be a
1918 syscall enter. If we last single-stepped this thread, this
1919 has to be a syscall exit.
1921 The points above mean that the next resume, be it PT_STEP or
1922 PT_CONTINUE, can not trigger a syscall trace event. */
1923 if (debug_linux_nat)
1924 fprintf_unfiltered (gdb_stdlog,
1925 "LHST: caught syscall event "
1926 "with no syscall catchpoints."
1927 " %d for LWP %ld, ignoring\n",
1929 ptid_get_lwp (lp->ptid));
1930 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1933 /* The core isn't interested in this event. For efficiency, avoid
1934 stopping all threads only to have the core resume them all again.
1935 Since we're not stopping threads, if we're still syscall tracing
1936 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1937 subsequent syscall. Simply resume using the inf-ptrace layer,
1938 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1940 /* Note that gdbarch_get_syscall_number may access registers, hence
1942 registers_changed ();
1943 if (linux_nat_prepare_to_resume != NULL)
1944 linux_nat_prepare_to_resume (lp);
1945 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
1946 lp->step, GDB_SIGNAL_0);
1950 /* Handle a GNU/Linux extended wait response. If we see a clone
1951 event, we need to add the new LWP to our list (and not report the
1952 trap to higher layers). This function returns non-zero if the
1953 event should be ignored and we should wait again. If STOPPING is
1954 true, the new LWP remains stopped, otherwise it is continued. */
1957 linux_handle_extended_wait (struct lwp_info *lp, int status,
1960 int pid = ptid_get_lwp (lp->ptid);
1961 struct target_waitstatus *ourstatus = &lp->waitstatus;
1962 int event = status >> 16;
1964 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1965 || event == PTRACE_EVENT_CLONE)
1967 unsigned long new_pid;
1970 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
1972 /* If we haven't already seen the new PID stop, wait for it now. */
1973 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
1975 /* The new child has a pending SIGSTOP. We can't affect it until it
1976 hits the SIGSTOP, but we're already attached. */
1977 ret = my_waitpid (new_pid, &status,
1978 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
1980 perror_with_name (_("waiting for new child"));
1981 else if (ret != new_pid)
1982 internal_error (__FILE__, __LINE__,
1983 _("wait returned unexpected PID %d"), ret);
1984 else if (!WIFSTOPPED (status))
1985 internal_error (__FILE__, __LINE__,
1986 _("wait returned unexpected status 0x%x"), status);
1989 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
1991 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
1993 /* The arch-specific native code may need to know about new
1994 forks even if those end up never mapped to an
1996 if (linux_nat_new_fork != NULL)
1997 linux_nat_new_fork (lp, new_pid);
2000 if (event == PTRACE_EVENT_FORK
2001 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
2003 /* Handle checkpointing by linux-fork.c here as a special
2004 case. We don't want the follow-fork-mode or 'catch fork'
2005 to interfere with this. */
2007 /* This won't actually modify the breakpoint list, but will
2008 physically remove the breakpoints from the child. */
2009 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
2011 /* Retain child fork in ptrace (stopped) state. */
2012 if (!find_fork_pid (new_pid))
2015 /* Report as spurious, so that infrun doesn't want to follow
2016 this fork. We're actually doing an infcall in
2018 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
2020 /* Report the stop to the core. */
2024 if (event == PTRACE_EVENT_FORK)
2025 ourstatus->kind = TARGET_WAITKIND_FORKED;
2026 else if (event == PTRACE_EVENT_VFORK)
2027 ourstatus->kind = TARGET_WAITKIND_VFORKED;
2030 struct lwp_info *new_lp;
2032 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2034 if (debug_linux_nat)
2035 fprintf_unfiltered (gdb_stdlog,
2036 "LHEW: Got clone event "
2037 "from LWP %d, new child is LWP %ld\n",
2040 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
2042 new_lp->stopped = 1;
2044 if (WSTOPSIG (status) != SIGSTOP)
2046 /* This can happen if someone starts sending signals to
2047 the new thread before it gets a chance to run, which
2048 have a lower number than SIGSTOP (e.g. SIGUSR1).
2049 This is an unlikely case, and harder to handle for
2050 fork / vfork than for clone, so we do not try - but
2051 we handle it for clone events here. We'll send
2052 the other signal on to the thread below. */
2054 new_lp->signalled = 1;
2058 struct thread_info *tp;
2060 /* When we stop for an event in some other thread, and
2061 pull the thread list just as this thread has cloned,
2062 we'll have seen the new thread in the thread_db list
2063 before handling the CLONE event (glibc's
2064 pthread_create adds the new thread to the thread list
2065 before clone'ing, and has the kernel fill in the
2066 thread's tid on the clone call with
2067 CLONE_PARENT_SETTID). If that happened, and the core
2068 had requested the new thread to stop, we'll have
2069 killed it with SIGSTOP. But since SIGSTOP is not an
2070 RT signal, it can only be queued once. We need to be
2071 careful to not resume the LWP if we wanted it to
2072 stop. In that case, we'll leave the SIGSTOP pending.
2073 It will later be reported as GDB_SIGNAL_0. */
2074 tp = find_thread_ptid (new_lp->ptid);
2075 if (tp != NULL && tp->stop_requested)
2076 new_lp->last_resume_kind = resume_stop;
2083 /* Add the new thread to GDB's lists as soon as possible
2086 1) the frontend doesn't have to wait for a stop to
2089 2) we tag it with the correct running state. */
2091 /* If the thread_db layer is active, let it know about
2092 this new thread, and add it to GDB's list. */
2093 if (!thread_db_attach_lwp (new_lp->ptid))
2095 /* We're not using thread_db. Add it to GDB's
2097 target_post_attach (ptid_get_lwp (new_lp->ptid));
2098 add_thread (new_lp->ptid);
2103 set_running (new_lp->ptid, 1);
2104 set_executing (new_lp->ptid, 1);
2105 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2107 new_lp->last_resume_kind = resume_continue;
2113 /* We created NEW_LP so it cannot yet contain STATUS. */
2114 gdb_assert (new_lp->status == 0);
2116 /* Save the wait status to report later. */
2117 if (debug_linux_nat)
2118 fprintf_unfiltered (gdb_stdlog,
2119 "LHEW: waitpid of new LWP %ld, "
2120 "saving status %s\n",
2121 (long) ptid_get_lwp (new_lp->ptid),
2122 status_to_str (status));
2123 new_lp->status = status;
2126 /* Note the need to use the low target ops to resume, to
2127 handle resuming with PT_SYSCALL if we have syscall
2131 new_lp->resumed = 1;
2135 gdb_assert (new_lp->last_resume_kind == resume_continue);
2136 if (debug_linux_nat)
2137 fprintf_unfiltered (gdb_stdlog,
2138 "LHEW: resuming new LWP %ld\n",
2139 ptid_get_lwp (new_lp->ptid));
2140 if (linux_nat_prepare_to_resume != NULL)
2141 linux_nat_prepare_to_resume (new_lp);
2142 linux_ops->to_resume (linux_ops, pid_to_ptid (new_pid),
2144 new_lp->stopped = 0;
2148 if (debug_linux_nat)
2149 fprintf_unfiltered (gdb_stdlog,
2150 "LHEW: resuming parent LWP %d\n", pid);
2151 if (linux_nat_prepare_to_resume != NULL)
2152 linux_nat_prepare_to_resume (lp);
2153 linux_ops->to_resume (linux_ops,
2154 pid_to_ptid (ptid_get_lwp (lp->ptid)),
2163 if (event == PTRACE_EVENT_EXEC)
2165 if (debug_linux_nat)
2166 fprintf_unfiltered (gdb_stdlog,
2167 "LHEW: Got exec event from LWP %ld\n",
2168 ptid_get_lwp (lp->ptid));
2170 ourstatus->kind = TARGET_WAITKIND_EXECD;
2171 ourstatus->value.execd_pathname
2172 = xstrdup (linux_child_pid_to_exec_file (NULL, pid));
2177 if (event == PTRACE_EVENT_VFORK_DONE)
2179 if (current_inferior ()->waiting_for_vfork_done)
2181 if (debug_linux_nat)
2182 fprintf_unfiltered (gdb_stdlog,
2183 "LHEW: Got expected PTRACE_EVENT_"
2184 "VFORK_DONE from LWP %ld: stopping\n",
2185 ptid_get_lwp (lp->ptid));
2187 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2191 if (debug_linux_nat)
2192 fprintf_unfiltered (gdb_stdlog,
2193 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2194 "from LWP %ld: resuming\n",
2195 ptid_get_lwp (lp->ptid));
2196 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2200 internal_error (__FILE__, __LINE__,
2201 _("unknown ptrace event %d"), event);
2204 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2208 wait_lwp (struct lwp_info *lp)
2212 int thread_dead = 0;
2215 gdb_assert (!lp->stopped);
2216 gdb_assert (lp->status == 0);
2218 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2219 block_child_signals (&prev_mask);
2223 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2224 was right and we should just call sigsuspend. */
2226 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
2227 if (pid == -1 && errno == ECHILD)
2228 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
2229 if (pid == -1 && errno == ECHILD)
2231 /* The thread has previously exited. We need to delete it
2232 now because, for some vendor 2.4 kernels with NPTL
2233 support backported, there won't be an exit event unless
2234 it is the main thread. 2.6 kernels will report an exit
2235 event for each thread that exits, as expected. */
2237 if (debug_linux_nat)
2238 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2239 target_pid_to_str (lp->ptid));
2244 /* Bugs 10970, 12702.
2245 Thread group leader may have exited in which case we'll lock up in
2246 waitpid if there are other threads, even if they are all zombies too.
2247 Basically, we're not supposed to use waitpid this way.
2248 __WCLONE is not applicable for the leader so we can't use that.
2249 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2250 process; it gets ESRCH both for the zombie and for running processes.
2252 As a workaround, check if we're waiting for the thread group leader and
2253 if it's a zombie, and avoid calling waitpid if it is.
2255 This is racy, what if the tgl becomes a zombie right after we check?
2256 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2257 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2259 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2260 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2263 if (debug_linux_nat)
2264 fprintf_unfiltered (gdb_stdlog,
2265 "WL: Thread group leader %s vanished.\n",
2266 target_pid_to_str (lp->ptid));
2270 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2271 get invoked despite our caller had them intentionally blocked by
2272 block_child_signals. This is sensitive only to the loop of
2273 linux_nat_wait_1 and there if we get called my_waitpid gets called
2274 again before it gets to sigsuspend so we can safely let the handlers
2275 get executed here. */
2277 sigsuspend (&suspend_mask);
2280 restore_child_signals_mask (&prev_mask);
2284 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2286 if (debug_linux_nat)
2288 fprintf_unfiltered (gdb_stdlog,
2289 "WL: waitpid %s received %s\n",
2290 target_pid_to_str (lp->ptid),
2291 status_to_str (status));
2294 /* Check if the thread has exited. */
2295 if (WIFEXITED (status) || WIFSIGNALED (status))
2298 if (debug_linux_nat)
2299 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2300 target_pid_to_str (lp->ptid));
2310 gdb_assert (WIFSTOPPED (status));
2312 /* Handle GNU/Linux's syscall SIGTRAPs. */
2313 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2315 /* No longer need the sysgood bit. The ptrace event ends up
2316 recorded in lp->waitstatus if we care for it. We can carry
2317 on handling the event like a regular SIGTRAP from here
2319 status = W_STOPCODE (SIGTRAP);
2320 if (linux_handle_syscall_trap (lp, 1))
2321 return wait_lwp (lp);
2324 /* Handle GNU/Linux's extended waitstatus for trace events. */
2325 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2327 if (debug_linux_nat)
2328 fprintf_unfiltered (gdb_stdlog,
2329 "WL: Handling extended status 0x%06x\n",
2331 if (linux_handle_extended_wait (lp, status, 1))
2332 return wait_lwp (lp);
2338 /* Send a SIGSTOP to LP. */
2341 stop_callback (struct lwp_info *lp, void *data)
2343 if (!lp->stopped && !lp->signalled)
2347 if (debug_linux_nat)
2349 fprintf_unfiltered (gdb_stdlog,
2350 "SC: kill %s **<SIGSTOP>**\n",
2351 target_pid_to_str (lp->ptid));
2354 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2355 if (debug_linux_nat)
2357 fprintf_unfiltered (gdb_stdlog,
2358 "SC: lwp kill %d %s\n",
2360 errno ? safe_strerror (errno) : "ERRNO-OK");
2364 gdb_assert (lp->status == 0);
2370 /* Request a stop on LWP. */
2373 linux_stop_lwp (struct lwp_info *lwp)
2375 stop_callback (lwp, NULL);
2378 /* Return non-zero if LWP PID has a pending SIGINT. */
2381 linux_nat_has_pending_sigint (int pid)
2383 sigset_t pending, blocked, ignored;
2385 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2387 if (sigismember (&pending, SIGINT)
2388 && !sigismember (&ignored, SIGINT))
2394 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2397 set_ignore_sigint (struct lwp_info *lp, void *data)
2399 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2400 flag to consume the next one. */
2401 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2402 && WSTOPSIG (lp->status) == SIGINT)
2405 lp->ignore_sigint = 1;
2410 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2411 This function is called after we know the LWP has stopped; if the LWP
2412 stopped before the expected SIGINT was delivered, then it will never have
2413 arrived. Also, if the signal was delivered to a shared queue and consumed
2414 by a different thread, it will never be delivered to this LWP. */
2417 maybe_clear_ignore_sigint (struct lwp_info *lp)
2419 if (!lp->ignore_sigint)
2422 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2424 if (debug_linux_nat)
2425 fprintf_unfiltered (gdb_stdlog,
2426 "MCIS: Clearing bogus flag for %s\n",
2427 target_pid_to_str (lp->ptid));
2428 lp->ignore_sigint = 0;
2432 /* Fetch the possible triggered data watchpoint info and store it in
2435 On some archs, like x86, that use debug registers to set
2436 watchpoints, it's possible that the way to know which watched
2437 address trapped, is to check the register that is used to select
2438 which address to watch. Problem is, between setting the watchpoint
2439 and reading back which data address trapped, the user may change
2440 the set of watchpoints, and, as a consequence, GDB changes the
2441 debug registers in the inferior. To avoid reading back a stale
2442 stopped-data-address when that happens, we cache in LP the fact
2443 that a watchpoint trapped, and the corresponding data address, as
2444 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2445 registers meanwhile, we have the cached data we can rely on. */
2448 save_sigtrap (struct lwp_info *lp)
2450 struct cleanup *old_chain;
2452 if (linux_ops->to_stopped_by_watchpoint == NULL)
2454 lp->stopped_by_watchpoint = 0;
2458 old_chain = save_inferior_ptid ();
2459 inferior_ptid = lp->ptid;
2461 lp->stopped_by_watchpoint = linux_ops->to_stopped_by_watchpoint (linux_ops);
2463 if (lp->stopped_by_watchpoint)
2465 if (linux_ops->to_stopped_data_address != NULL)
2466 lp->stopped_data_address_p =
2467 linux_ops->to_stopped_data_address (¤t_target,
2468 &lp->stopped_data_address);
2470 lp->stopped_data_address_p = 0;
2473 do_cleanups (old_chain);
2476 /* See save_sigtrap. */
2479 linux_nat_stopped_by_watchpoint (struct target_ops *ops)
2481 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2483 gdb_assert (lp != NULL);
2485 return lp->stopped_by_watchpoint;
2489 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2491 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2493 gdb_assert (lp != NULL);
2495 *addr_p = lp->stopped_data_address;
2497 return lp->stopped_data_address_p;
2500 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2503 sigtrap_is_event (int status)
2505 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2508 /* SIGTRAP-like events recognizer. */
2510 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
2512 /* Check for SIGTRAP-like events in LP. */
2515 linux_nat_lp_status_is_event (struct lwp_info *lp)
2517 /* We check for lp->waitstatus in addition to lp->status, because we can
2518 have pending process exits recorded in lp->status
2519 and W_EXITCODE(0,0) == 0. We should probably have an additional
2520 lp->status_p flag. */
2522 return (lp->waitstatus.kind == TARGET_WAITKIND_IGNORE
2523 && linux_nat_status_is_event (lp->status));
2526 /* Set alternative SIGTRAP-like events recognizer. If
2527 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2531 linux_nat_set_status_is_event (struct target_ops *t,
2532 int (*status_is_event) (int status))
2534 linux_nat_status_is_event = status_is_event;
2537 /* Wait until LP is stopped. */
2540 stop_wait_callback (struct lwp_info *lp, void *data)
2542 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2544 /* If this is a vfork parent, bail out, it is not going to report
2545 any SIGSTOP until the vfork is done with. */
2546 if (inf->vfork_child != NULL)
2553 status = wait_lwp (lp);
2557 if (lp->ignore_sigint && WIFSTOPPED (status)
2558 && WSTOPSIG (status) == SIGINT)
2560 lp->ignore_sigint = 0;
2563 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2564 if (debug_linux_nat)
2565 fprintf_unfiltered (gdb_stdlog,
2566 "PTRACE_CONT %s, 0, 0 (%s) "
2567 "(discarding SIGINT)\n",
2568 target_pid_to_str (lp->ptid),
2569 errno ? safe_strerror (errno) : "OK");
2571 return stop_wait_callback (lp, NULL);
2574 maybe_clear_ignore_sigint (lp);
2576 if (WSTOPSIG (status) != SIGSTOP)
2578 /* The thread was stopped with a signal other than SIGSTOP. */
2582 if (debug_linux_nat)
2583 fprintf_unfiltered (gdb_stdlog,
2584 "SWC: Pending event %s in %s\n",
2585 status_to_str ((int) status),
2586 target_pid_to_str (lp->ptid));
2588 /* Save the sigtrap event. */
2589 lp->status = status;
2590 gdb_assert (!lp->stopped);
2591 gdb_assert (lp->signalled);
2596 /* We caught the SIGSTOP that we intended to catch, so
2597 there's no SIGSTOP pending. */
2599 if (debug_linux_nat)
2600 fprintf_unfiltered (gdb_stdlog,
2601 "SWC: Delayed SIGSTOP caught for %s.\n",
2602 target_pid_to_str (lp->ptid));
2606 /* Reset SIGNALLED only after the stop_wait_callback call
2607 above as it does gdb_assert on SIGNALLED. */
2615 /* Return non-zero if LP has a wait status pending. */
2618 status_callback (struct lwp_info *lp, void *data)
2620 /* Only report a pending wait status if we pretend that this has
2621 indeed been resumed. */
2625 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2627 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2628 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2629 0', so a clean process exit can not be stored pending in
2630 lp->status, it is indistinguishable from
2631 no-pending-status. */
2635 if (lp->status != 0)
2641 /* Return non-zero if LP isn't stopped. */
2644 running_callback (struct lwp_info *lp, void *data)
2646 return (!lp->stopped
2647 || ((lp->status != 0
2648 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2652 /* Count the LWP's that have had events. */
2655 count_events_callback (struct lwp_info *lp, void *data)
2659 gdb_assert (count != NULL);
2661 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2662 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2668 /* Select the LWP (if any) that is currently being single-stepped. */
2671 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2673 if (lp->last_resume_kind == resume_step
2680 /* Select the Nth LWP that has had a SIGTRAP event. */
2683 select_event_lwp_callback (struct lwp_info *lp, void *data)
2685 int *selector = data;
2687 gdb_assert (selector != NULL);
2689 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2690 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2691 if ((*selector)-- == 0)
2698 cancel_breakpoint (struct lwp_info *lp)
2700 /* Arrange for a breakpoint to be hit again later. We don't keep
2701 the SIGTRAP status and don't forward the SIGTRAP signal to the
2702 LWP. We will handle the current event, eventually we will resume
2703 this LWP, and this breakpoint will trap again.
2705 If we do not do this, then we run the risk that the user will
2706 delete or disable the breakpoint, but the LWP will have already
2709 struct regcache *regcache = get_thread_regcache (lp->ptid);
2710 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2713 pc = regcache_read_pc (regcache) - target_decr_pc_after_break (gdbarch);
2714 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2716 if (debug_linux_nat)
2717 fprintf_unfiltered (gdb_stdlog,
2718 "CB: Push back breakpoint for %s\n",
2719 target_pid_to_str (lp->ptid));
2721 /* Back up the PC if necessary. */
2722 if (target_decr_pc_after_break (gdbarch))
2723 regcache_write_pc (regcache, pc);
2731 cancel_breakpoints_callback (struct lwp_info *lp, void *data)
2733 struct lwp_info *event_lp = data;
2735 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2739 /* If a LWP other than the LWP that we're reporting an event for has
2740 hit a GDB breakpoint (as opposed to some random trap signal),
2741 then just arrange for it to hit it again later. We don't keep
2742 the SIGTRAP status and don't forward the SIGTRAP signal to the
2743 LWP. We will handle the current event, eventually we will resume
2744 all LWPs, and this one will get its breakpoint trap again.
2746 If we do not do this, then we run the risk that the user will
2747 delete or disable the breakpoint, but the LWP will have already
2750 if (linux_nat_lp_status_is_event (lp)
2751 && cancel_breakpoint (lp))
2752 /* Throw away the SIGTRAP. */
2758 /* Select one LWP out of those that have events pending. */
2761 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2764 int random_selector;
2765 struct lwp_info *event_lp;
2767 /* Record the wait status for the original LWP. */
2768 (*orig_lp)->status = *status;
2770 /* Give preference to any LWP that is being single-stepped. */
2771 event_lp = iterate_over_lwps (filter,
2772 select_singlestep_lwp_callback, NULL);
2773 if (event_lp != NULL)
2775 if (debug_linux_nat)
2776 fprintf_unfiltered (gdb_stdlog,
2777 "SEL: Select single-step %s\n",
2778 target_pid_to_str (event_lp->ptid));
2782 /* No single-stepping LWP. Select one at random, out of those
2783 which have had SIGTRAP events. */
2785 /* First see how many SIGTRAP events we have. */
2786 iterate_over_lwps (filter, count_events_callback, &num_events);
2788 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2789 random_selector = (int)
2790 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2792 if (debug_linux_nat && num_events > 1)
2793 fprintf_unfiltered (gdb_stdlog,
2794 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2795 num_events, random_selector);
2797 event_lp = iterate_over_lwps (filter,
2798 select_event_lwp_callback,
2802 if (event_lp != NULL)
2804 /* Switch the event LWP. */
2805 *orig_lp = event_lp;
2806 *status = event_lp->status;
2809 /* Flush the wait status for the event LWP. */
2810 (*orig_lp)->status = 0;
2813 /* Return non-zero if LP has been resumed. */
2816 resumed_callback (struct lwp_info *lp, void *data)
2821 /* Stop an active thread, verify it still exists, then resume it. If
2822 the thread ends up with a pending status, then it is not resumed,
2823 and *DATA (really a pointer to int), is set. */
2826 stop_and_resume_callback (struct lwp_info *lp, void *data)
2828 int *new_pending_p = data;
2832 ptid_t ptid = lp->ptid;
2834 stop_callback (lp, NULL);
2835 stop_wait_callback (lp, NULL);
2837 /* Resume if the lwp still exists, and the core wanted it
2839 lp = find_lwp_pid (ptid);
2842 if (lp->last_resume_kind == resume_stop
2845 /* The core wanted the LWP to stop. Even if it stopped
2846 cleanly (with SIGSTOP), leave the event pending. */
2847 if (debug_linux_nat)
2848 fprintf_unfiltered (gdb_stdlog,
2849 "SARC: core wanted LWP %ld stopped "
2850 "(leaving SIGSTOP pending)\n",
2851 ptid_get_lwp (lp->ptid));
2852 lp->status = W_STOPCODE (SIGSTOP);
2855 if (lp->status == 0)
2857 if (debug_linux_nat)
2858 fprintf_unfiltered (gdb_stdlog,
2859 "SARC: re-resuming LWP %ld\n",
2860 ptid_get_lwp (lp->ptid));
2861 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
2865 if (debug_linux_nat)
2866 fprintf_unfiltered (gdb_stdlog,
2867 "SARC: not re-resuming LWP %ld "
2869 ptid_get_lwp (lp->ptid));
2878 /* Check if we should go on and pass this event to common code.
2879 Return the affected lwp if we are, or NULL otherwise. If we stop
2880 all lwps temporarily, we may end up with new pending events in some
2881 other lwp. In that case set *NEW_PENDING_P to true. */
2883 static struct lwp_info *
2884 linux_nat_filter_event (int lwpid, int status, int *new_pending_p)
2886 struct lwp_info *lp;
2890 lp = find_lwp_pid (pid_to_ptid (lwpid));
2892 /* Check for stop events reported by a process we didn't already
2893 know about - anything not already in our LWP list.
2895 If we're expecting to receive stopped processes after
2896 fork, vfork, and clone events, then we'll just add the
2897 new one to our list and go back to waiting for the event
2898 to be reported - the stopped process might be returned
2899 from waitpid before or after the event is.
2901 But note the case of a non-leader thread exec'ing after the
2902 leader having exited, and gone from our lists. The non-leader
2903 thread changes its tid to the tgid. */
2905 if (WIFSTOPPED (status) && lp == NULL
2906 && (WSTOPSIG (status) == SIGTRAP && status >> 16 == PTRACE_EVENT_EXEC))
2908 /* A multi-thread exec after we had seen the leader exiting. */
2909 if (debug_linux_nat)
2910 fprintf_unfiltered (gdb_stdlog,
2911 "LLW: Re-adding thread group leader LWP %d.\n",
2914 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
2917 add_thread (lp->ptid);
2920 if (WIFSTOPPED (status) && !lp)
2922 add_to_pid_list (&stopped_pids, lwpid, status);
2926 /* Make sure we don't report an event for the exit of an LWP not in
2927 our list, i.e. not part of the current process. This can happen
2928 if we detach from a program we originally forked and then it
2930 if (!WIFSTOPPED (status) && !lp)
2933 /* Handle GNU/Linux's syscall SIGTRAPs. */
2934 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2936 /* No longer need the sysgood bit. The ptrace event ends up
2937 recorded in lp->waitstatus if we care for it. We can carry
2938 on handling the event like a regular SIGTRAP from here
2940 status = W_STOPCODE (SIGTRAP);
2941 if (linux_handle_syscall_trap (lp, 0))
2945 /* Handle GNU/Linux's extended waitstatus for trace events. */
2946 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2948 if (debug_linux_nat)
2949 fprintf_unfiltered (gdb_stdlog,
2950 "LLW: Handling extended status 0x%06x\n",
2952 if (linux_handle_extended_wait (lp, status, 0))
2956 if (linux_nat_status_is_event (status))
2959 /* Check if the thread has exited. */
2960 if ((WIFEXITED (status) || WIFSIGNALED (status))
2961 && num_lwps (ptid_get_pid (lp->ptid)) > 1)
2963 /* If this is the main thread, we must stop all threads and verify
2964 if they are still alive. This is because in the nptl thread model
2965 on Linux 2.4, there is no signal issued for exiting LWPs
2966 other than the main thread. We only get the main thread exit
2967 signal once all child threads have already exited. If we
2968 stop all the threads and use the stop_wait_callback to check
2969 if they have exited we can determine whether this signal
2970 should be ignored or whether it means the end of the debugged
2971 application, regardless of which threading model is being
2973 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
2976 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
2977 stop_and_resume_callback, new_pending_p);
2980 if (debug_linux_nat)
2981 fprintf_unfiltered (gdb_stdlog,
2982 "LLW: %s exited.\n",
2983 target_pid_to_str (lp->ptid));
2985 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
2987 /* If there is at least one more LWP, then the exit signal
2988 was not the end of the debugged application and should be
2995 /* Check if the current LWP has previously exited. In the nptl
2996 thread model, LWPs other than the main thread do not issue
2997 signals when they exit so we must check whenever the thread has
2998 stopped. A similar check is made in stop_wait_callback(). */
2999 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3001 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
3003 if (debug_linux_nat)
3004 fprintf_unfiltered (gdb_stdlog,
3005 "LLW: %s exited.\n",
3006 target_pid_to_str (lp->ptid));
3010 /* Make sure there is at least one thread running. */
3011 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3013 /* Discard the event. */
3017 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3018 an attempt to stop an LWP. */
3020 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3022 if (debug_linux_nat)
3023 fprintf_unfiltered (gdb_stdlog,
3024 "LLW: Delayed SIGSTOP caught for %s.\n",
3025 target_pid_to_str (lp->ptid));
3029 if (lp->last_resume_kind != resume_stop)
3031 /* This is a delayed SIGSTOP. */
3033 registers_changed ();
3035 if (linux_nat_prepare_to_resume != NULL)
3036 linux_nat_prepare_to_resume (lp);
3037 linux_ops->to_resume (linux_ops,
3038 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3039 lp->step, GDB_SIGNAL_0);
3040 if (debug_linux_nat)
3041 fprintf_unfiltered (gdb_stdlog,
3042 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3044 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3045 target_pid_to_str (lp->ptid));
3048 gdb_assert (lp->resumed);
3050 /* Discard the event. */
3055 /* Make sure we don't report a SIGINT that we have already displayed
3056 for another thread. */
3057 if (lp->ignore_sigint
3058 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3060 if (debug_linux_nat)
3061 fprintf_unfiltered (gdb_stdlog,
3062 "LLW: Delayed SIGINT caught for %s.\n",
3063 target_pid_to_str (lp->ptid));
3065 /* This is a delayed SIGINT. */
3066 lp->ignore_sigint = 0;
3068 registers_changed ();
3069 if (linux_nat_prepare_to_resume != NULL)
3070 linux_nat_prepare_to_resume (lp);
3071 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3072 lp->step, GDB_SIGNAL_0);
3073 if (debug_linux_nat)
3074 fprintf_unfiltered (gdb_stdlog,
3075 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3077 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3078 target_pid_to_str (lp->ptid));
3081 gdb_assert (lp->resumed);
3083 /* Discard the event. */
3087 /* An interesting event. */
3089 lp->status = status;
3093 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3094 their exits until all other threads in the group have exited. */
3097 check_zombie_leaders (void)
3099 struct inferior *inf;
3103 struct lwp_info *leader_lp;
3108 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3109 if (leader_lp != NULL
3110 /* Check if there are other threads in the group, as we may
3111 have raced with the inferior simply exiting. */
3112 && num_lwps (inf->pid) > 1
3113 && linux_proc_pid_is_zombie (inf->pid))
3115 if (debug_linux_nat)
3116 fprintf_unfiltered (gdb_stdlog,
3117 "CZL: Thread group leader %d zombie "
3118 "(it exited, or another thread execd).\n",
3121 /* A leader zombie can mean one of two things:
3123 - It exited, and there's an exit status pending
3124 available, or only the leader exited (not the whole
3125 program). In the latter case, we can't waitpid the
3126 leader's exit status until all other threads are gone.
3128 - There are 3 or more threads in the group, and a thread
3129 other than the leader exec'd. On an exec, the Linux
3130 kernel destroys all other threads (except the execing
3131 one) in the thread group, and resets the execing thread's
3132 tid to the tgid. No exit notification is sent for the
3133 execing thread -- from the ptracer's perspective, it
3134 appears as though the execing thread just vanishes.
3135 Until we reap all other threads except the leader and the
3136 execing thread, the leader will be zombie, and the
3137 execing thread will be in `D (disc sleep)'. As soon as
3138 all other threads are reaped, the execing thread changes
3139 it's tid to the tgid, and the previous (zombie) leader
3140 vanishes, giving place to the "new" leader. We could try
3141 distinguishing the exit and exec cases, by waiting once
3142 more, and seeing if something comes out, but it doesn't
3143 sound useful. The previous leader _does_ go away, and
3144 we'll re-add the new one once we see the exec event
3145 (which is just the same as what would happen if the
3146 previous leader did exit voluntarily before some other
3149 if (debug_linux_nat)
3150 fprintf_unfiltered (gdb_stdlog,
3151 "CZL: Thread group leader %d vanished.\n",
3153 exit_lwp (leader_lp);
3159 linux_nat_wait_1 (struct target_ops *ops,
3160 ptid_t ptid, struct target_waitstatus *ourstatus,
3163 static sigset_t prev_mask;
3164 enum resume_kind last_resume_kind;
3165 struct lwp_info *lp;
3168 if (debug_linux_nat)
3169 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3171 /* The first time we get here after starting a new inferior, we may
3172 not have added it to the LWP list yet - this is the earliest
3173 moment at which we know its PID. */
3174 if (ptid_is_pid (inferior_ptid))
3176 /* Upgrade the main thread's ptid. */
3177 thread_change_ptid (inferior_ptid,
3178 ptid_build (ptid_get_pid (inferior_ptid),
3179 ptid_get_pid (inferior_ptid), 0));
3181 lp = add_initial_lwp (inferior_ptid);
3185 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3186 block_child_signals (&prev_mask);
3192 /* First check if there is a LWP with a wait status pending. */
3193 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3195 /* Any LWP in the PTID group that's been resumed will do. */
3196 lp = iterate_over_lwps (ptid, status_callback, NULL);
3199 if (debug_linux_nat && lp->status)
3200 fprintf_unfiltered (gdb_stdlog,
3201 "LLW: Using pending wait status %s for %s.\n",
3202 status_to_str (lp->status),
3203 target_pid_to_str (lp->ptid));
3206 else if (ptid_lwp_p (ptid))
3208 if (debug_linux_nat)
3209 fprintf_unfiltered (gdb_stdlog,
3210 "LLW: Waiting for specific LWP %s.\n",
3211 target_pid_to_str (ptid));
3213 /* We have a specific LWP to check. */
3214 lp = find_lwp_pid (ptid);
3217 if (debug_linux_nat && lp->status)
3218 fprintf_unfiltered (gdb_stdlog,
3219 "LLW: Using pending wait status %s for %s.\n",
3220 status_to_str (lp->status),
3221 target_pid_to_str (lp->ptid));
3223 /* We check for lp->waitstatus in addition to lp->status,
3224 because we can have pending process exits recorded in
3225 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3226 an additional lp->status_p flag. */
3227 if (lp->status == 0 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3231 if (!target_can_async_p ())
3233 /* Causes SIGINT to be passed on to the attached process. */
3237 /* But if we don't find a pending event, we'll have to wait. */
3243 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3246 - If the thread group leader exits while other threads in the
3247 thread group still exist, waitpid(TGID, ...) hangs. That
3248 waitpid won't return an exit status until the other threads
3249 in the group are reapped.
3251 - When a non-leader thread execs, that thread just vanishes
3252 without reporting an exit (so we'd hang if we waited for it
3253 explicitly in that case). The exec event is reported to
3257 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3258 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3259 lwpid = my_waitpid (-1, &status, WNOHANG);
3261 if (debug_linux_nat)
3262 fprintf_unfiltered (gdb_stdlog,
3263 "LNW: waitpid(-1, ...) returned %d, %s\n",
3264 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3268 /* If this is true, then we paused LWPs momentarily, and may
3269 now have pending events to handle. */
3272 if (debug_linux_nat)
3274 fprintf_unfiltered (gdb_stdlog,
3275 "LLW: waitpid %ld received %s\n",
3276 (long) lwpid, status_to_str (status));
3279 lp = linux_nat_filter_event (lwpid, status, &new_pending);
3281 /* STATUS is now no longer valid, use LP->STATUS instead. */
3284 if (lp && !ptid_match (lp->ptid, ptid))
3286 gdb_assert (lp->resumed);
3288 if (debug_linux_nat)
3290 "LWP %ld got an event %06x, leaving pending.\n",
3291 ptid_get_lwp (lp->ptid), lp->status);
3293 if (WIFSTOPPED (lp->status))
3295 if (WSTOPSIG (lp->status) != SIGSTOP)
3297 /* Cancel breakpoint hits. The breakpoint may
3298 be removed before we fetch events from this
3299 process to report to the core. It is best
3300 not to assume the moribund breakpoints
3301 heuristic always handles these cases --- it
3302 could be too many events go through to the
3303 core before this one is handled. All-stop
3304 always cancels breakpoint hits in all
3307 && linux_nat_lp_status_is_event (lp)
3308 && cancel_breakpoint (lp))
3310 /* Throw away the SIGTRAP. */
3313 if (debug_linux_nat)
3315 "LLW: LWP %ld hit a breakpoint while"
3316 " waiting for another process;"
3318 ptid_get_lwp (lp->ptid));
3328 else if (WIFEXITED (lp->status) || WIFSIGNALED (lp->status))
3330 if (debug_linux_nat)
3332 "Process %ld exited while stopping LWPs\n",
3333 ptid_get_lwp (lp->ptid));
3335 /* This was the last lwp in the process. Since
3336 events are serialized to GDB core, and we can't
3337 report this one right now, but GDB core and the
3338 other target layers will want to be notified
3339 about the exit code/signal, leave the status
3340 pending for the next time we're able to report
3343 /* Prevent trying to stop this thread again. We'll
3344 never try to resume it because it has a pending
3348 /* Dead LWP's aren't expected to reported a pending
3352 /* Store the pending event in the waitstatus as
3353 well, because W_EXITCODE(0,0) == 0. */
3354 store_waitstatus (&lp->waitstatus, lp->status);
3363 /* Some LWP now has a pending event. Go all the way
3364 back to check it. */
3370 /* We got an event to report to the core. */
3374 /* Retry until nothing comes out of waitpid. A single
3375 SIGCHLD can indicate more than one child stopped. */
3379 /* Check for zombie thread group leaders. Those can't be reaped
3380 until all other threads in the thread group are. */
3381 check_zombie_leaders ();
3383 /* If there are no resumed children left, bail. We'd be stuck
3384 forever in the sigsuspend call below otherwise. */
3385 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3387 if (debug_linux_nat)
3388 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3390 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3392 if (!target_can_async_p ())
3393 clear_sigint_trap ();
3395 restore_child_signals_mask (&prev_mask);
3396 return minus_one_ptid;
3399 /* No interesting event to report to the core. */
3401 if (target_options & TARGET_WNOHANG)
3403 if (debug_linux_nat)
3404 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3406 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3407 restore_child_signals_mask (&prev_mask);
3408 return minus_one_ptid;
3411 /* We shouldn't end up here unless we want to try again. */
3412 gdb_assert (lp == NULL);
3414 /* Block until we get an event reported with SIGCHLD. */
3415 sigsuspend (&suspend_mask);
3418 if (!target_can_async_p ())
3419 clear_sigint_trap ();
3423 status = lp->status;
3426 /* Don't report signals that GDB isn't interested in, such as
3427 signals that are neither printed nor stopped upon. Stopping all
3428 threads can be a bit time-consuming so if we want decent
3429 performance with heavily multi-threaded programs, especially when
3430 they're using a high frequency timer, we'd better avoid it if we
3433 if (WIFSTOPPED (status))
3435 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3437 /* When using hardware single-step, we need to report every signal.
3438 Otherwise, signals in pass_mask may be short-circuited. */
3440 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status)))
3442 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3443 here? It is not clear we should. GDB may not expect
3444 other threads to run. On the other hand, not resuming
3445 newly attached threads may cause an unwanted delay in
3446 getting them running. */
3447 registers_changed ();
3448 if (linux_nat_prepare_to_resume != NULL)
3449 linux_nat_prepare_to_resume (lp);
3450 linux_ops->to_resume (linux_ops,
3451 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3453 if (debug_linux_nat)
3454 fprintf_unfiltered (gdb_stdlog,
3455 "LLW: %s %s, %s (preempt 'handle')\n",
3457 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3458 target_pid_to_str (lp->ptid),
3459 (signo != GDB_SIGNAL_0
3460 ? strsignal (gdb_signal_to_host (signo))
3468 /* Only do the below in all-stop, as we currently use SIGINT
3469 to implement target_stop (see linux_nat_stop) in
3471 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3473 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3474 forwarded to the entire process group, that is, all LWPs
3475 will receive it - unless they're using CLONE_THREAD to
3476 share signals. Since we only want to report it once, we
3477 mark it as ignored for all LWPs except this one. */
3478 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid)),
3479 set_ignore_sigint, NULL);
3480 lp->ignore_sigint = 0;
3483 maybe_clear_ignore_sigint (lp);
3487 /* This LWP is stopped now. */
3490 if (debug_linux_nat)
3491 fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
3492 status_to_str (status), target_pid_to_str (lp->ptid));
3496 /* Now stop all other LWP's ... */
3497 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3499 /* ... and wait until all of them have reported back that
3500 they're no longer running. */
3501 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3503 /* If we're not waiting for a specific LWP, choose an event LWP
3504 from among those that have had events. Giving equal priority
3505 to all LWPs that have had events helps prevent
3507 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3508 select_event_lwp (ptid, &lp, &status);
3510 /* Now that we've selected our final event LWP, cancel any
3511 breakpoints in other LWPs that have hit a GDB breakpoint.
3512 See the comment in cancel_breakpoints_callback to find out
3514 iterate_over_lwps (minus_one_ptid, cancel_breakpoints_callback, lp);
3516 /* We'll need this to determine whether to report a SIGSTOP as
3517 TARGET_WAITKIND_0. Need to take a copy because
3518 resume_clear_callback clears it. */
3519 last_resume_kind = lp->last_resume_kind;
3521 /* In all-stop, from the core's perspective, all LWPs are now
3522 stopped until a new resume action is sent over. */
3523 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3528 last_resume_kind = lp->last_resume_kind;
3529 resume_clear_callback (lp, NULL);
3532 if (linux_nat_status_is_event (status))
3534 if (debug_linux_nat)
3535 fprintf_unfiltered (gdb_stdlog,
3536 "LLW: trap ptid is %s.\n",
3537 target_pid_to_str (lp->ptid));
3540 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3542 *ourstatus = lp->waitstatus;
3543 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3546 store_waitstatus (ourstatus, status);
3548 if (debug_linux_nat)
3549 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3551 restore_child_signals_mask (&prev_mask);
3553 if (last_resume_kind == resume_stop
3554 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3555 && WSTOPSIG (status) == SIGSTOP)
3557 /* A thread that has been requested to stop by GDB with
3558 target_stop, and it stopped cleanly, so report as SIG0. The
3559 use of SIGSTOP is an implementation detail. */
3560 ourstatus->value.sig = GDB_SIGNAL_0;
3563 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3564 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3567 lp->core = linux_common_core_of_thread (lp->ptid);
3572 /* Resume LWPs that are currently stopped without any pending status
3573 to report, but are resumed from the core's perspective. */
3576 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3578 ptid_t *wait_ptid_p = data;
3583 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3585 struct regcache *regcache = get_thread_regcache (lp->ptid);
3586 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3587 CORE_ADDR pc = regcache_read_pc (regcache);
3589 gdb_assert (is_executing (lp->ptid));
3591 /* Don't bother if there's a breakpoint at PC that we'd hit
3592 immediately, and we're not waiting for this LWP. */
3593 if (!ptid_match (lp->ptid, *wait_ptid_p))
3595 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3599 if (debug_linux_nat)
3600 fprintf_unfiltered (gdb_stdlog,
3601 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3602 target_pid_to_str (lp->ptid),
3603 paddress (gdbarch, pc),
3606 registers_changed ();
3607 if (linux_nat_prepare_to_resume != NULL)
3608 linux_nat_prepare_to_resume (lp);
3609 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3610 lp->step, GDB_SIGNAL_0);
3612 lp->stopped_by_watchpoint = 0;
3619 linux_nat_wait (struct target_ops *ops,
3620 ptid_t ptid, struct target_waitstatus *ourstatus,
3625 if (debug_linux_nat)
3627 char *options_string;
3629 options_string = target_options_to_string (target_options);
3630 fprintf_unfiltered (gdb_stdlog,
3631 "linux_nat_wait: [%s], [%s]\n",
3632 target_pid_to_str (ptid),
3634 xfree (options_string);
3637 /* Flush the async file first. */
3638 if (target_can_async_p ())
3639 async_file_flush ();
3641 /* Resume LWPs that are currently stopped without any pending status
3642 to report, but are resumed from the core's perspective. LWPs get
3643 in this state if we find them stopping at a time we're not
3644 interested in reporting the event (target_wait on a
3645 specific_process, for example, see linux_nat_wait_1), and
3646 meanwhile the event became uninteresting. Don't bother resuming
3647 LWPs we're not going to wait for if they'd stop immediately. */
3649 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3651 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3653 /* If we requested any event, and something came out, assume there
3654 may be more. If we requested a specific lwp or process, also
3655 assume there may be more. */
3656 if (target_can_async_p ()
3657 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3658 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3659 || !ptid_equal (ptid, minus_one_ptid)))
3662 /* Get ready for the next event. */
3663 if (target_can_async_p ())
3664 target_async (inferior_event_handler, 0);
3670 kill_callback (struct lwp_info *lp, void *data)
3672 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3675 kill (ptid_get_lwp (lp->ptid), SIGKILL);
3676 if (debug_linux_nat)
3677 fprintf_unfiltered (gdb_stdlog,
3678 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3679 target_pid_to_str (lp->ptid),
3680 errno ? safe_strerror (errno) : "OK");
3682 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3685 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3686 if (debug_linux_nat)
3687 fprintf_unfiltered (gdb_stdlog,
3688 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3689 target_pid_to_str (lp->ptid),
3690 errno ? safe_strerror (errno) : "OK");
3696 kill_wait_callback (struct lwp_info *lp, void *data)
3700 /* We must make sure that there are no pending events (delayed
3701 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3702 program doesn't interfere with any following debugging session. */
3704 /* For cloned processes we must check both with __WCLONE and
3705 without, since the exit status of a cloned process isn't reported
3711 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3712 if (pid != (pid_t) -1)
3714 if (debug_linux_nat)
3715 fprintf_unfiltered (gdb_stdlog,
3716 "KWC: wait %s received unknown.\n",
3717 target_pid_to_str (lp->ptid));
3718 /* The Linux kernel sometimes fails to kill a thread
3719 completely after PTRACE_KILL; that goes from the stop
3720 point in do_fork out to the one in
3721 get_signal_to_deliever and waits again. So kill it
3723 kill_callback (lp, NULL);
3726 while (pid == ptid_get_lwp (lp->ptid));
3728 gdb_assert (pid == -1 && errno == ECHILD);
3733 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3734 if (pid != (pid_t) -1)
3736 if (debug_linux_nat)
3737 fprintf_unfiltered (gdb_stdlog,
3738 "KWC: wait %s received unk.\n",
3739 target_pid_to_str (lp->ptid));
3740 /* See the call to kill_callback above. */
3741 kill_callback (lp, NULL);
3744 while (pid == ptid_get_lwp (lp->ptid));
3746 gdb_assert (pid == -1 && errno == ECHILD);
3751 linux_nat_kill (struct target_ops *ops)
3753 struct target_waitstatus last;
3757 /* If we're stopped while forking and we haven't followed yet,
3758 kill the other task. We need to do this first because the
3759 parent will be sleeping if this is a vfork. */
3761 get_last_target_status (&last_ptid, &last);
3763 if (last.kind == TARGET_WAITKIND_FORKED
3764 || last.kind == TARGET_WAITKIND_VFORKED)
3766 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3769 /* Let the arch-specific native code know this process is
3771 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3774 if (forks_exist_p ())
3775 linux_fork_killall ();
3778 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3780 /* Stop all threads before killing them, since ptrace requires
3781 that the thread is stopped to sucessfully PTRACE_KILL. */
3782 iterate_over_lwps (ptid, stop_callback, NULL);
3783 /* ... and wait until all of them have reported back that
3784 they're no longer running. */
3785 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3787 /* Kill all LWP's ... */
3788 iterate_over_lwps (ptid, kill_callback, NULL);
3790 /* ... and wait until we've flushed all events. */
3791 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3794 target_mourn_inferior ();
3798 linux_nat_mourn_inferior (struct target_ops *ops)
3800 int pid = ptid_get_pid (inferior_ptid);
3802 purge_lwp_list (pid);
3804 if (! forks_exist_p ())
3805 /* Normal case, no other forks available. */
3806 linux_ops->to_mourn_inferior (ops);
3808 /* Multi-fork case. The current inferior_ptid has exited, but
3809 there are other viable forks to debug. Delete the exiting
3810 one and context-switch to the first available. */
3811 linux_fork_mourn_inferior ();
3813 /* Let the arch-specific native code know this process is gone. */
3814 linux_nat_forget_process (pid);
3817 /* Convert a native/host siginfo object, into/from the siginfo in the
3818 layout of the inferiors' architecture. */
3821 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3825 if (linux_nat_siginfo_fixup != NULL)
3826 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3828 /* If there was no callback, or the callback didn't do anything,
3829 then just do a straight memcpy. */
3833 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3835 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3839 static enum target_xfer_status
3840 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3841 const char *annex, gdb_byte *readbuf,
3842 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3843 ULONGEST *xfered_len)
3847 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3849 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3850 gdb_assert (readbuf || writebuf);
3852 pid = ptid_get_lwp (inferior_ptid);
3854 pid = ptid_get_pid (inferior_ptid);
3856 if (offset > sizeof (siginfo))
3857 return TARGET_XFER_E_IO;
3860 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3862 return TARGET_XFER_E_IO;
3864 /* When GDB is built as a 64-bit application, ptrace writes into
3865 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3866 inferior with a 64-bit GDB should look the same as debugging it
3867 with a 32-bit GDB, we need to convert it. GDB core always sees
3868 the converted layout, so any read/write will have to be done
3870 siginfo_fixup (&siginfo, inf_siginfo, 0);
3872 if (offset + len > sizeof (siginfo))
3873 len = sizeof (siginfo) - offset;
3875 if (readbuf != NULL)
3876 memcpy (readbuf, inf_siginfo + offset, len);
3879 memcpy (inf_siginfo + offset, writebuf, len);
3881 /* Convert back to ptrace layout before flushing it out. */
3882 siginfo_fixup (&siginfo, inf_siginfo, 1);
3885 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3887 return TARGET_XFER_E_IO;
3891 return TARGET_XFER_OK;
3894 static enum target_xfer_status
3895 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3896 const char *annex, gdb_byte *readbuf,
3897 const gdb_byte *writebuf,
3898 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3900 struct cleanup *old_chain;
3901 enum target_xfer_status xfer;
3903 if (object == TARGET_OBJECT_SIGNAL_INFO)
3904 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3905 offset, len, xfered_len);
3907 /* The target is connected but no live inferior is selected. Pass
3908 this request down to a lower stratum (e.g., the executable
3910 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3911 return TARGET_XFER_EOF;
3913 old_chain = save_inferior_ptid ();
3915 if (ptid_lwp_p (inferior_ptid))
3916 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3918 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3919 offset, len, xfered_len);
3921 do_cleanups (old_chain);
3926 linux_thread_alive (ptid_t ptid)
3930 gdb_assert (ptid_lwp_p (ptid));
3932 /* Send signal 0 instead of anything ptrace, because ptracing a
3933 running thread errors out claiming that the thread doesn't
3935 err = kill_lwp (ptid_get_lwp (ptid), 0);
3937 if (debug_linux_nat)
3938 fprintf_unfiltered (gdb_stdlog,
3939 "LLTA: KILL(SIG0) %s (%s)\n",
3940 target_pid_to_str (ptid),
3941 err ? safe_strerror (tmp_errno) : "OK");
3950 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3952 return linux_thread_alive (ptid);
3956 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3958 static char buf[64];
3960 if (ptid_lwp_p (ptid)
3961 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
3962 || num_lwps (ptid_get_pid (ptid)) > 1))
3964 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
3968 return normal_pid_to_str (ptid);
3972 linux_nat_thread_name (struct target_ops *self, struct thread_info *thr)
3974 int pid = ptid_get_pid (thr->ptid);
3975 long lwp = ptid_get_lwp (thr->ptid);
3976 #define FORMAT "/proc/%d/task/%ld/comm"
3977 char buf[sizeof (FORMAT) + 30];
3979 char *result = NULL;
3981 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
3982 comm_file = gdb_fopen_cloexec (buf, "r");
3985 /* Not exported by the kernel, so we define it here. */
3987 static char line[COMM_LEN + 1];
3989 if (fgets (line, sizeof (line), comm_file))
3991 char *nl = strchr (line, '\n');
4008 /* Accepts an integer PID; Returns a string representing a file that
4009 can be opened to get the symbols for the child process. */
4012 linux_child_pid_to_exec_file (struct target_ops *self, int pid)
4014 static char buf[PATH_MAX];
4015 char name[PATH_MAX];
4017 xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
4018 memset (buf, 0, PATH_MAX);
4019 if (readlink (name, buf, PATH_MAX - 1) <= 0)
4025 /* Records the thread's register state for the corefile note
4029 linux_nat_collect_thread_registers (const struct regcache *regcache,
4030 ptid_t ptid, bfd *obfd,
4031 char *note_data, int *note_size,
4032 enum gdb_signal stop_signal)
4034 struct gdbarch *gdbarch = get_regcache_arch (regcache);
4035 const struct regset *regset;
4037 gdb_gregset_t gregs;
4038 gdb_fpregset_t fpregs;
4040 core_regset_p = gdbarch_regset_from_core_section_p (gdbarch);
4043 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg",
4045 != NULL && regset->collect_regset != NULL)
4046 regset->collect_regset (regset, regcache, -1, &gregs, sizeof (gregs));
4048 fill_gregset (regcache, &gregs, -1);
4050 note_data = (char *) elfcore_write_prstatus
4051 (obfd, note_data, note_size, ptid_get_lwp (ptid),
4052 gdb_signal_to_host (stop_signal), &gregs);
4055 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
4057 != NULL && regset->collect_regset != NULL)
4058 regset->collect_regset (regset, regcache, -1, &fpregs, sizeof (fpregs));
4060 fill_fpregset (regcache, &fpregs, -1);
4062 note_data = (char *) elfcore_write_prfpreg (obfd, note_data, note_size,
4063 &fpregs, sizeof (fpregs));
4068 /* Fills the "to_make_corefile_note" target vector. Builds the note
4069 section for a corefile, and returns it in a malloc buffer. */
4072 linux_nat_make_corefile_notes (struct target_ops *self,
4073 bfd *obfd, int *note_size)
4075 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4076 converted to gdbarch_core_regset_sections, this function can go away. */
4077 return linux_make_corefile_notes (target_gdbarch (), obfd, note_size,
4078 linux_nat_collect_thread_registers);
4081 /* Implement the to_xfer_partial interface for memory reads using the /proc
4082 filesystem. Because we can use a single read() call for /proc, this
4083 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4084 but it doesn't support writes. */
4086 static enum target_xfer_status
4087 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
4088 const char *annex, gdb_byte *readbuf,
4089 const gdb_byte *writebuf,
4090 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
4096 if (object != TARGET_OBJECT_MEMORY || !readbuf)
4099 /* Don't bother for one word. */
4100 if (len < 3 * sizeof (long))
4101 return TARGET_XFER_EOF;
4103 /* We could keep this file open and cache it - possibly one per
4104 thread. That requires some juggling, but is even faster. */
4105 xsnprintf (filename, sizeof filename, "/proc/%d/mem",
4106 ptid_get_pid (inferior_ptid));
4107 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
4109 return TARGET_XFER_EOF;
4111 /* If pread64 is available, use it. It's faster if the kernel
4112 supports it (only one syscall), and it's 64-bit safe even on
4113 32-bit platforms (for instance, SPARC debugging a SPARC64
4116 if (pread64 (fd, readbuf, len, offset) != len)
4118 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
4127 return TARGET_XFER_EOF;
4131 return TARGET_XFER_OK;
4136 /* Enumerate spufs IDs for process PID. */
4138 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
4140 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4142 LONGEST written = 0;
4145 struct dirent *entry;
4147 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4148 dir = opendir (path);
4153 while ((entry = readdir (dir)) != NULL)
4159 fd = atoi (entry->d_name);
4163 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4164 if (stat (path, &st) != 0)
4166 if (!S_ISDIR (st.st_mode))
4169 if (statfs (path, &stfs) != 0)
4171 if (stfs.f_type != SPUFS_MAGIC)
4174 if (pos >= offset && pos + 4 <= offset + len)
4176 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4186 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4187 object type, using the /proc file system. */
4189 static enum target_xfer_status
4190 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
4191 const char *annex, gdb_byte *readbuf,
4192 const gdb_byte *writebuf,
4193 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
4198 int pid = ptid_get_pid (inferior_ptid);
4203 return TARGET_XFER_E_IO;
4206 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
4209 return TARGET_XFER_E_IO;
4211 return TARGET_XFER_EOF;
4214 *xfered_len = (ULONGEST) l;
4215 return TARGET_XFER_OK;
4220 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4221 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4223 return TARGET_XFER_E_IO;
4226 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4229 return TARGET_XFER_EOF;
4233 ret = write (fd, writebuf, (size_t) len);
4235 ret = read (fd, readbuf, (size_t) len);
4240 return TARGET_XFER_E_IO;
4242 return TARGET_XFER_EOF;
4245 *xfered_len = (ULONGEST) ret;
4246 return TARGET_XFER_OK;
4251 /* Parse LINE as a signal set and add its set bits to SIGS. */
4254 add_line_to_sigset (const char *line, sigset_t *sigs)
4256 int len = strlen (line) - 1;
4260 if (line[len] != '\n')
4261 error (_("Could not parse signal set: %s"), line);
4269 if (*p >= '0' && *p <= '9')
4271 else if (*p >= 'a' && *p <= 'f')
4272 digit = *p - 'a' + 10;
4274 error (_("Could not parse signal set: %s"), line);
4279 sigaddset (sigs, signum + 1);
4281 sigaddset (sigs, signum + 2);
4283 sigaddset (sigs, signum + 3);
4285 sigaddset (sigs, signum + 4);
4291 /* Find process PID's pending signals from /proc/pid/status and set
4295 linux_proc_pending_signals (int pid, sigset_t *pending,
4296 sigset_t *blocked, sigset_t *ignored)
4299 char buffer[PATH_MAX], fname[PATH_MAX];
4300 struct cleanup *cleanup;
4302 sigemptyset (pending);
4303 sigemptyset (blocked);
4304 sigemptyset (ignored);
4305 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4306 procfile = gdb_fopen_cloexec (fname, "r");
4307 if (procfile == NULL)
4308 error (_("Could not open %s"), fname);
4309 cleanup = make_cleanup_fclose (procfile);
4311 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4313 /* Normal queued signals are on the SigPnd line in the status
4314 file. However, 2.6 kernels also have a "shared" pending
4315 queue for delivering signals to a thread group, so check for
4318 Unfortunately some Red Hat kernels include the shared pending
4319 queue but not the ShdPnd status field. */
4321 if (strncmp (buffer, "SigPnd:\t", 8) == 0)
4322 add_line_to_sigset (buffer + 8, pending);
4323 else if (strncmp (buffer, "ShdPnd:\t", 8) == 0)
4324 add_line_to_sigset (buffer + 8, pending);
4325 else if (strncmp (buffer, "SigBlk:\t", 8) == 0)
4326 add_line_to_sigset (buffer + 8, blocked);
4327 else if (strncmp (buffer, "SigIgn:\t", 8) == 0)
4328 add_line_to_sigset (buffer + 8, ignored);
4331 do_cleanups (cleanup);
4334 static enum target_xfer_status
4335 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4336 const char *annex, gdb_byte *readbuf,
4337 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4338 ULONGEST *xfered_len)
4340 gdb_assert (object == TARGET_OBJECT_OSDATA);
4342 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4343 if (*xfered_len == 0)
4344 return TARGET_XFER_EOF;
4346 return TARGET_XFER_OK;
4349 static enum target_xfer_status
4350 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4351 const char *annex, gdb_byte *readbuf,
4352 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4353 ULONGEST *xfered_len)
4355 enum target_xfer_status xfer;
4357 if (object == TARGET_OBJECT_AUXV)
4358 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4359 offset, len, xfered_len);
4361 if (object == TARGET_OBJECT_OSDATA)
4362 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4363 offset, len, xfered_len);
4365 if (object == TARGET_OBJECT_SPU)
4366 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4367 offset, len, xfered_len);
4369 /* GDB calculates all the addresses in possibly larget width of the address.
4370 Address width needs to be masked before its final use - either by
4371 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4373 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4375 if (object == TARGET_OBJECT_MEMORY)
4377 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4379 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4380 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4383 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4384 offset, len, xfered_len);
4385 if (xfer != TARGET_XFER_EOF)
4388 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4389 offset, len, xfered_len);
4393 cleanup_target_stop (void *arg)
4395 ptid_t *ptid = (ptid_t *) arg;
4397 gdb_assert (arg != NULL);
4400 target_resume (*ptid, 0, GDB_SIGNAL_0);
4403 static VEC(static_tracepoint_marker_p) *
4404 linux_child_static_tracepoint_markers_by_strid (struct target_ops *self,
4407 char s[IPA_CMD_BUF_SIZE];
4408 struct cleanup *old_chain;
4409 int pid = ptid_get_pid (inferior_ptid);
4410 VEC(static_tracepoint_marker_p) *markers = NULL;
4411 struct static_tracepoint_marker *marker = NULL;
4413 ptid_t ptid = ptid_build (pid, 0, 0);
4418 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4419 s[sizeof ("qTfSTM")] = 0;
4421 agent_run_command (pid, s, strlen (s) + 1);
4423 old_chain = make_cleanup (free_current_marker, &marker);
4424 make_cleanup (cleanup_target_stop, &ptid);
4429 marker = XCNEW (struct static_tracepoint_marker);
4433 parse_static_tracepoint_marker_definition (p, &p, marker);
4435 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4437 VEC_safe_push (static_tracepoint_marker_p,
4443 release_static_tracepoint_marker (marker);
4444 memset (marker, 0, sizeof (*marker));
4447 while (*p++ == ','); /* comma-separated list */
4449 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4450 s[sizeof ("qTsSTM")] = 0;
4451 agent_run_command (pid, s, strlen (s) + 1);
4455 do_cleanups (old_chain);
4460 /* Create a prototype generic GNU/Linux target. The client can override
4461 it with local methods. */
4464 linux_target_install_ops (struct target_ops *t)
4466 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4467 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4468 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4469 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4470 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4471 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4472 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4473 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4474 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4475 t->to_post_attach = linux_child_post_attach;
4476 t->to_follow_fork = linux_child_follow_fork;
4477 t->to_make_corefile_notes = linux_nat_make_corefile_notes;
4479 super_xfer_partial = t->to_xfer_partial;
4480 t->to_xfer_partial = linux_xfer_partial;
4482 t->to_static_tracepoint_markers_by_strid
4483 = linux_child_static_tracepoint_markers_by_strid;
4489 struct target_ops *t;
4491 t = inf_ptrace_target ();
4492 linux_target_install_ops (t);
4498 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4500 struct target_ops *t;
4502 t = inf_ptrace_trad_target (register_u_offset);
4503 linux_target_install_ops (t);
4508 /* target_is_async_p implementation. */
4511 linux_nat_is_async_p (struct target_ops *ops)
4513 /* NOTE: palves 2008-03-21: We're only async when the user requests
4514 it explicitly with the "set target-async" command.
4515 Someday, linux will always be async. */
4516 return target_async_permitted;
4519 /* target_can_async_p implementation. */
4522 linux_nat_can_async_p (struct target_ops *ops)
4524 /* NOTE: palves 2008-03-21: We're only async when the user requests
4525 it explicitly with the "set target-async" command.
4526 Someday, linux will always be async. */
4527 return target_async_permitted;
4531 linux_nat_supports_non_stop (struct target_ops *self)
4536 /* True if we want to support multi-process. To be removed when GDB
4537 supports multi-exec. */
4539 int linux_multi_process = 1;
4542 linux_nat_supports_multi_process (struct target_ops *self)
4544 return linux_multi_process;
4548 linux_nat_supports_disable_randomization (struct target_ops *self)
4550 #ifdef HAVE_PERSONALITY
4557 static int async_terminal_is_ours = 1;
4559 /* target_terminal_inferior implementation. */
4562 linux_nat_terminal_inferior (struct target_ops *self)
4564 if (!target_is_async_p ())
4566 /* Async mode is disabled. */
4567 child_terminal_inferior (self);
4571 child_terminal_inferior (self);
4573 /* Calls to target_terminal_*() are meant to be idempotent. */
4574 if (!async_terminal_is_ours)
4577 delete_file_handler (input_fd);
4578 async_terminal_is_ours = 0;
4582 /* target_terminal_ours implementation. */
4585 linux_nat_terminal_ours (struct target_ops *self)
4587 if (!target_is_async_p ())
4589 /* Async mode is disabled. */
4590 child_terminal_ours (self);
4594 /* GDB should never give the terminal to the inferior if the
4595 inferior is running in the background (run&, continue&, etc.),
4596 but claiming it sure should. */
4597 child_terminal_ours (self);
4599 if (async_terminal_is_ours)
4602 clear_sigint_trap ();
4603 add_file_handler (input_fd, stdin_event_handler, 0);
4604 async_terminal_is_ours = 1;
4607 static void (*async_client_callback) (enum inferior_event_type event_type,
4609 static void *async_client_context;
4611 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4612 so we notice when any child changes state, and notify the
4613 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4614 above to wait for the arrival of a SIGCHLD. */
4617 sigchld_handler (int signo)
4619 int old_errno = errno;
4621 if (debug_linux_nat)
4622 ui_file_write_async_safe (gdb_stdlog,
4623 "sigchld\n", sizeof ("sigchld\n") - 1);
4625 if (signo == SIGCHLD
4626 && linux_nat_event_pipe[0] != -1)
4627 async_file_mark (); /* Let the event loop know that there are
4628 events to handle. */
4633 /* Callback registered with the target events file descriptor. */
4636 handle_target_event (int error, gdb_client_data client_data)
4638 (*async_client_callback) (INF_REG_EVENT, async_client_context);
4641 /* Create/destroy the target events pipe. Returns previous state. */
4644 linux_async_pipe (int enable)
4646 int previous = (linux_nat_event_pipe[0] != -1);
4648 if (previous != enable)
4652 /* Block child signals while we create/destroy the pipe, as
4653 their handler writes to it. */
4654 block_child_signals (&prev_mask);
4658 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4659 internal_error (__FILE__, __LINE__,
4660 "creating event pipe failed.");
4662 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4663 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4667 close (linux_nat_event_pipe[0]);
4668 close (linux_nat_event_pipe[1]);
4669 linux_nat_event_pipe[0] = -1;
4670 linux_nat_event_pipe[1] = -1;
4673 restore_child_signals_mask (&prev_mask);
4679 /* target_async implementation. */
4682 linux_nat_async (struct target_ops *ops,
4683 void (*callback) (enum inferior_event_type event_type,
4687 if (callback != NULL)
4689 async_client_callback = callback;
4690 async_client_context = context;
4691 if (!linux_async_pipe (1))
4693 add_file_handler (linux_nat_event_pipe[0],
4694 handle_target_event, NULL);
4695 /* There may be pending events to handle. Tell the event loop
4702 async_client_callback = callback;
4703 async_client_context = context;
4704 delete_file_handler (linux_nat_event_pipe[0]);
4705 linux_async_pipe (0);
4710 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4714 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4718 if (debug_linux_nat)
4719 fprintf_unfiltered (gdb_stdlog,
4720 "LNSL: running -> suspending %s\n",
4721 target_pid_to_str (lwp->ptid));
4724 if (lwp->last_resume_kind == resume_stop)
4726 if (debug_linux_nat)
4727 fprintf_unfiltered (gdb_stdlog,
4728 "linux-nat: already stopping LWP %ld at "
4730 ptid_get_lwp (lwp->ptid));
4734 stop_callback (lwp, NULL);
4735 lwp->last_resume_kind = resume_stop;
4739 /* Already known to be stopped; do nothing. */
4741 if (debug_linux_nat)
4743 if (find_thread_ptid (lwp->ptid)->stop_requested)
4744 fprintf_unfiltered (gdb_stdlog,
4745 "LNSL: already stopped/stop_requested %s\n",
4746 target_pid_to_str (lwp->ptid));
4748 fprintf_unfiltered (gdb_stdlog,
4749 "LNSL: already stopped/no "
4750 "stop_requested yet %s\n",
4751 target_pid_to_str (lwp->ptid));
4758 linux_nat_stop (struct target_ops *self, ptid_t ptid)
4761 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4763 linux_ops->to_stop (linux_ops, ptid);
4767 linux_nat_close (struct target_ops *self)
4769 /* Unregister from the event loop. */
4770 if (linux_nat_is_async_p (NULL))
4771 linux_nat_async (NULL, NULL, 0);
4773 if (linux_ops->to_close)
4774 linux_ops->to_close (linux_ops);
4777 /* When requests are passed down from the linux-nat layer to the
4778 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4779 used. The address space pointer is stored in the inferior object,
4780 but the common code that is passed such ptid can't tell whether
4781 lwpid is a "main" process id or not (it assumes so). We reverse
4782 look up the "main" process id from the lwp here. */
4784 static struct address_space *
4785 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4787 struct lwp_info *lwp;
4788 struct inferior *inf;
4791 pid = ptid_get_lwp (ptid);
4792 if (ptid_get_lwp (ptid) == 0)
4794 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4796 lwp = find_lwp_pid (ptid);
4797 pid = ptid_get_pid (lwp->ptid);
4801 /* A (pid,lwpid,0) ptid. */
4802 pid = ptid_get_pid (ptid);
4805 inf = find_inferior_pid (pid);
4806 gdb_assert (inf != NULL);
4810 /* Return the cached value of the processor core for thread PTID. */
4813 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4815 struct lwp_info *info = find_lwp_pid (ptid);
4823 linux_nat_add_target (struct target_ops *t)
4825 /* Save the provided single-threaded target. We save this in a separate
4826 variable because another target we've inherited from (e.g. inf-ptrace)
4827 may have saved a pointer to T; we want to use it for the final
4828 process stratum target. */
4829 linux_ops_saved = *t;
4830 linux_ops = &linux_ops_saved;
4832 /* Override some methods for multithreading. */
4833 t->to_create_inferior = linux_nat_create_inferior;
4834 t->to_attach = linux_nat_attach;
4835 t->to_detach = linux_nat_detach;
4836 t->to_resume = linux_nat_resume;
4837 t->to_wait = linux_nat_wait;
4838 t->to_pass_signals = linux_nat_pass_signals;
4839 t->to_xfer_partial = linux_nat_xfer_partial;
4840 t->to_kill = linux_nat_kill;
4841 t->to_mourn_inferior = linux_nat_mourn_inferior;
4842 t->to_thread_alive = linux_nat_thread_alive;
4843 t->to_pid_to_str = linux_nat_pid_to_str;
4844 t->to_thread_name = linux_nat_thread_name;
4845 t->to_has_thread_control = tc_schedlock;
4846 t->to_thread_address_space = linux_nat_thread_address_space;
4847 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4848 t->to_stopped_data_address = linux_nat_stopped_data_address;
4850 t->to_can_async_p = linux_nat_can_async_p;
4851 t->to_is_async_p = linux_nat_is_async_p;
4852 t->to_supports_non_stop = linux_nat_supports_non_stop;
4853 t->to_async = linux_nat_async;
4854 t->to_terminal_inferior = linux_nat_terminal_inferior;
4855 t->to_terminal_ours = linux_nat_terminal_ours;
4856 t->to_close = linux_nat_close;
4858 /* Methods for non-stop support. */
4859 t->to_stop = linux_nat_stop;
4861 t->to_supports_multi_process = linux_nat_supports_multi_process;
4863 t->to_supports_disable_randomization
4864 = linux_nat_supports_disable_randomization;
4866 t->to_core_of_thread = linux_nat_core_of_thread;
4868 /* We don't change the stratum; this target will sit at
4869 process_stratum and thread_db will set at thread_stratum. This
4870 is a little strange, since this is a multi-threaded-capable
4871 target, but we want to be on the stack below thread_db, and we
4872 also want to be used for single-threaded processes. */
4877 /* Register a method to call whenever a new thread is attached. */
4879 linux_nat_set_new_thread (struct target_ops *t,
4880 void (*new_thread) (struct lwp_info *))
4882 /* Save the pointer. We only support a single registered instance
4883 of the GNU/Linux native target, so we do not need to map this to
4885 linux_nat_new_thread = new_thread;
4888 /* See declaration in linux-nat.h. */
4891 linux_nat_set_new_fork (struct target_ops *t,
4892 linux_nat_new_fork_ftype *new_fork)
4894 /* Save the pointer. */
4895 linux_nat_new_fork = new_fork;
4898 /* See declaration in linux-nat.h. */
4901 linux_nat_set_forget_process (struct target_ops *t,
4902 linux_nat_forget_process_ftype *fn)
4904 /* Save the pointer. */
4905 linux_nat_forget_process_hook = fn;
4908 /* See declaration in linux-nat.h. */
4911 linux_nat_forget_process (pid_t pid)
4913 if (linux_nat_forget_process_hook != NULL)
4914 linux_nat_forget_process_hook (pid);
4917 /* Register a method that converts a siginfo object between the layout
4918 that ptrace returns, and the layout in the architecture of the
4921 linux_nat_set_siginfo_fixup (struct target_ops *t,
4922 int (*siginfo_fixup) (siginfo_t *,
4926 /* Save the pointer. */
4927 linux_nat_siginfo_fixup = siginfo_fixup;
4930 /* Register a method to call prior to resuming a thread. */
4933 linux_nat_set_prepare_to_resume (struct target_ops *t,
4934 void (*prepare_to_resume) (struct lwp_info *))
4936 /* Save the pointer. */
4937 linux_nat_prepare_to_resume = prepare_to_resume;
4940 /* See linux-nat.h. */
4943 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4947 pid = ptid_get_lwp (ptid);
4949 pid = ptid_get_pid (ptid);
4952 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4955 memset (siginfo, 0, sizeof (*siginfo));
4961 /* Provide a prototype to silence -Wmissing-prototypes. */
4962 extern initialize_file_ftype _initialize_linux_nat;
4965 _initialize_linux_nat (void)
4967 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4968 &debug_linux_nat, _("\
4969 Set debugging of GNU/Linux lwp module."), _("\
4970 Show debugging of GNU/Linux lwp module."), _("\
4971 Enables printf debugging output."),
4973 show_debug_linux_nat,
4974 &setdebuglist, &showdebuglist);
4976 /* Save this mask as the default. */
4977 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
4979 /* Install a SIGCHLD handler. */
4980 sigchld_action.sa_handler = sigchld_handler;
4981 sigemptyset (&sigchld_action.sa_mask);
4982 sigchld_action.sa_flags = SA_RESTART;
4984 /* Make it the default. */
4985 sigaction (SIGCHLD, &sigchld_action, NULL);
4987 /* Make sure we don't block SIGCHLD during a sigsuspend. */
4988 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
4989 sigdelset (&suspend_mask, SIGCHLD);
4991 sigemptyset (&blocked_mask);
4995 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
4996 the GNU/Linux Threads library and therefore doesn't really belong
4999 /* Read variable NAME in the target and return its value if found.
5000 Otherwise return zero. It is assumed that the type of the variable
5004 get_signo (const char *name)
5006 struct bound_minimal_symbol ms;
5009 ms = lookup_minimal_symbol (name, NULL, NULL);
5010 if (ms.minsym == NULL)
5013 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
5014 sizeof (signo)) != 0)
5020 /* Return the set of signals used by the threads library in *SET. */
5023 lin_thread_get_thread_signals (sigset_t *set)
5025 struct sigaction action;
5026 int restart, cancel;
5028 sigemptyset (&blocked_mask);
5031 restart = get_signo ("__pthread_sig_restart");
5032 cancel = get_signo ("__pthread_sig_cancel");
5034 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5035 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5036 not provide any way for the debugger to query the signal numbers -
5037 fortunately they don't change! */
5040 restart = __SIGRTMIN;
5043 cancel = __SIGRTMIN + 1;
5045 sigaddset (set, restart);
5046 sigaddset (set, cancel);
5048 /* The GNU/Linux Threads library makes terminating threads send a
5049 special "cancel" signal instead of SIGCHLD. Make sure we catch
5050 those (to prevent them from terminating GDB itself, which is
5051 likely to be their default action) and treat them the same way as
5054 action.sa_handler = sigchld_handler;
5055 sigemptyset (&action.sa_mask);
5056 action.sa_flags = SA_RESTART;
5057 sigaction (cancel, &action, NULL);
5059 /* We block the "cancel" signal throughout this code ... */
5060 sigaddset (&blocked_mask, cancel);
5061 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
5063 /* ... except during a sigsuspend. */
5064 sigdelset (&suspend_mask, cancel);