1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2014 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
28 #include "gdb_assert.h"
29 #ifdef HAVE_TKILL_SYSCALL
31 #include <sys/syscall.h>
33 #include <sys/ptrace.h>
34 #include "linux-nat.h"
35 #include "linux-ptrace.h"
36 #include "linux-procfs.h"
37 #include "linux-fork.h"
38 #include "gdbthread.h"
42 #include "inf-child.h"
43 #include "inf-ptrace.h"
45 #include <sys/procfs.h> /* for elf_gregset etc. */
46 #include "elf-bfd.h" /* for elfcore_write_* */
47 #include "gregset.h" /* for gregset */
48 #include "gdbcore.h" /* for get_exec_file */
49 #include <ctype.h> /* for isdigit */
50 #include <sys/stat.h> /* for struct stat */
51 #include <fcntl.h> /* for O_RDONLY */
53 #include "event-loop.h"
54 #include "event-top.h"
56 #include <sys/types.h>
58 #include "xml-support.h"
62 #include "linux-osdata.h"
63 #include "linux-tdep.h"
66 #include "tracepoint.h"
67 #include "exceptions.h"
69 #include "target-descriptions.h"
70 #include "filestuff.h"
74 #define SPUFS_MAGIC 0x23c9b64e
77 #ifdef HAVE_PERSONALITY
78 # include <sys/personality.h>
79 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
80 # define ADDR_NO_RANDOMIZE 0x0040000
82 #endif /* HAVE_PERSONALITY */
84 /* This comment documents high-level logic of this file.
86 Waiting for events in sync mode
87 ===============================
89 When waiting for an event in a specific thread, we just use waitpid, passing
90 the specific pid, and not passing WNOHANG.
92 When waiting for an event in all threads, waitpid is not quite good. Prior to
93 version 2.4, Linux can either wait for event in main thread, or in secondary
94 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
95 miss an event. The solution is to use non-blocking waitpid, together with
96 sigsuspend. First, we use non-blocking waitpid to get an event in the main
97 process, if any. Second, we use non-blocking waitpid with the __WCLONED
98 flag to check for events in cloned processes. If nothing is found, we use
99 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
100 happened to a child process -- and SIGCHLD will be delivered both for events
101 in main debugged process and in cloned processes. As soon as we know there's
102 an event, we get back to calling nonblocking waitpid with and without
105 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
106 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
107 blocked, the signal becomes pending and sigsuspend immediately
108 notices it and returns.
110 Waiting for events in async mode
111 ================================
113 In async mode, GDB should always be ready to handle both user input
114 and target events, so neither blocking waitpid nor sigsuspend are
115 viable options. Instead, we should asynchronously notify the GDB main
116 event loop whenever there's an unprocessed event from the target. We
117 detect asynchronous target events by handling SIGCHLD signals. To
118 notify the event loop about target events, the self-pipe trick is used
119 --- a pipe is registered as waitable event source in the event loop,
120 the event loop select/poll's on the read end of this pipe (as well on
121 other event sources, e.g., stdin), and the SIGCHLD handler writes a
122 byte to this pipe. This is more portable than relying on
123 pselect/ppoll, since on kernels that lack those syscalls, libc
124 emulates them with select/poll+sigprocmask, and that is racy
125 (a.k.a. plain broken).
127 Obviously, if we fail to notify the event loop if there's a target
128 event, it's bad. OTOH, if we notify the event loop when there's no
129 event from the target, linux_nat_wait will detect that there's no real
130 event to report, and return event of type TARGET_WAITKIND_IGNORE.
131 This is mostly harmless, but it will waste time and is better avoided.
133 The main design point is that every time GDB is outside linux-nat.c,
134 we have a SIGCHLD handler installed that is called when something
135 happens to the target and notifies the GDB event loop. Whenever GDB
136 core decides to handle the event, and calls into linux-nat.c, we
137 process things as in sync mode, except that the we never block in
140 While processing an event, we may end up momentarily blocked in
141 waitpid calls. Those waitpid calls, while blocking, are guarantied to
142 return quickly. E.g., in all-stop mode, before reporting to the core
143 that an LWP hit a breakpoint, all LWPs are stopped by sending them
144 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
145 Note that this is different from blocking indefinitely waiting for the
146 next event --- here, we're already handling an event.
151 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
152 signal is not entirely significant; we just need for a signal to be delivered,
153 so that we can intercept it. SIGSTOP's advantage is that it can not be
154 blocked. A disadvantage is that it is not a real-time signal, so it can only
155 be queued once; we do not keep track of other sources of SIGSTOP.
157 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
158 use them, because they have special behavior when the signal is generated -
159 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
160 kills the entire thread group.
162 A delivered SIGSTOP would stop the entire thread group, not just the thread we
163 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
164 cancel it (by PTRACE_CONT without passing SIGSTOP).
166 We could use a real-time signal instead. This would solve those problems; we
167 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
168 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
169 generates it, and there are races with trying to find a signal that is not
173 #define O_LARGEFILE 0
176 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
177 the use of the multi-threaded target. */
178 static struct target_ops *linux_ops;
179 static struct target_ops linux_ops_saved;
181 /* The method to call, if any, when a new thread is attached. */
182 static void (*linux_nat_new_thread) (struct lwp_info *);
184 /* The method to call, if any, when a new fork is attached. */
185 static linux_nat_new_fork_ftype *linux_nat_new_fork;
187 /* The method to call, if any, when a process is no longer
189 static linux_nat_forget_process_ftype *linux_nat_forget_process_hook;
191 /* Hook to call prior to resuming a thread. */
192 static void (*linux_nat_prepare_to_resume) (struct lwp_info *);
194 /* The method to call, if any, when the siginfo object needs to be
195 converted between the layout returned by ptrace, and the layout in
196 the architecture of the inferior. */
197 static int (*linux_nat_siginfo_fixup) (siginfo_t *,
201 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
202 Called by our to_xfer_partial. */
203 static target_xfer_partial_ftype *super_xfer_partial;
205 /* The saved to_close method, inherited from inf-ptrace.c.
206 Called by our to_close. */
207 static void (*super_close) (struct target_ops *);
209 static unsigned int debug_linux_nat;
211 show_debug_linux_nat (struct ui_file *file, int from_tty,
212 struct cmd_list_element *c, const char *value)
214 fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
218 struct simple_pid_list
222 struct simple_pid_list *next;
224 struct simple_pid_list *stopped_pids;
226 /* Async mode support. */
228 /* The read/write ends of the pipe registered as waitable file in the
230 static int linux_nat_event_pipe[2] = { -1, -1 };
232 /* Flush the event pipe. */
235 async_file_flush (void)
242 ret = read (linux_nat_event_pipe[0], &buf, 1);
244 while (ret >= 0 || (ret == -1 && errno == EINTR));
247 /* Put something (anything, doesn't matter what, or how much) in event
248 pipe, so that the select/poll in the event-loop realizes we have
249 something to process. */
252 async_file_mark (void)
256 /* It doesn't really matter what the pipe contains, as long we end
257 up with something in it. Might as well flush the previous
263 ret = write (linux_nat_event_pipe[1], "+", 1);
265 while (ret == -1 && errno == EINTR);
267 /* Ignore EAGAIN. If the pipe is full, the event loop will already
268 be awakened anyway. */
271 static int kill_lwp (int lwpid, int signo);
273 static int stop_callback (struct lwp_info *lp, void *data);
275 static void block_child_signals (sigset_t *prev_mask);
276 static void restore_child_signals_mask (sigset_t *prev_mask);
279 static struct lwp_info *add_lwp (ptid_t ptid);
280 static void purge_lwp_list (int pid);
281 static void delete_lwp (ptid_t ptid);
282 static struct lwp_info *find_lwp_pid (ptid_t ptid);
285 /* Trivial list manipulation functions to keep track of a list of
286 new stopped processes. */
288 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
290 struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
293 new_pid->status = status;
294 new_pid->next = *listp;
299 in_pid_list_p (struct simple_pid_list *list, int pid)
301 struct simple_pid_list *p;
303 for (p = list; p != NULL; p = p->next)
310 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
312 struct simple_pid_list **p;
314 for (p = listp; *p != NULL; p = &(*p)->next)
315 if ((*p)->pid == pid)
317 struct simple_pid_list *next = (*p)->next;
319 *statusp = (*p)->status;
327 /* Initialize ptrace warnings and check for supported ptrace
328 features given PID. */
331 linux_init_ptrace (pid_t pid)
333 linux_enable_event_reporting (pid);
334 linux_ptrace_init_warnings ();
338 linux_child_post_attach (struct target_ops *self, int pid)
340 linux_init_ptrace (pid);
344 linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
346 linux_init_ptrace (ptid_get_pid (ptid));
349 /* Return the number of known LWPs in the tgid given by PID. */
357 for (lp = lwp_list; lp; lp = lp->next)
358 if (ptid_get_pid (lp->ptid) == pid)
364 /* Call delete_lwp with prototype compatible for make_cleanup. */
367 delete_lwp_cleanup (void *lp_voidp)
369 struct lwp_info *lp = lp_voidp;
371 delete_lwp (lp->ptid);
375 linux_child_follow_fork (struct target_ops *ops, int follow_child,
379 int parent_pid, child_pid;
381 has_vforked = (inferior_thread ()->pending_follow.kind
382 == TARGET_WAITKIND_VFORKED);
383 parent_pid = ptid_get_lwp (inferior_ptid);
385 parent_pid = ptid_get_pid (inferior_ptid);
387 = ptid_get_pid (inferior_thread ()->pending_follow.value.related_pid);
390 && !non_stop /* Non-stop always resumes both branches. */
391 && (!target_is_async_p () || sync_execution)
392 && !(follow_child || detach_fork || sched_multi))
394 /* The parent stays blocked inside the vfork syscall until the
395 child execs or exits. If we don't let the child run, then
396 the parent stays blocked. If we're telling the parent to run
397 in the foreground, the user will not be able to ctrl-c to get
398 back the terminal, effectively hanging the debug session. */
399 fprintf_filtered (gdb_stderr, _("\
400 Can not resume the parent process over vfork in the foreground while\n\
401 holding the child stopped. Try \"set detach-on-fork\" or \
402 \"set schedule-multiple\".\n"));
403 /* FIXME output string > 80 columns. */
409 struct lwp_info *child_lp = NULL;
411 /* We're already attached to the parent, by default. */
413 /* Detach new forked process? */
416 struct cleanup *old_chain;
419 /* Before detaching from the child, remove all breakpoints
420 from it. If we forked, then this has already been taken
421 care of by infrun.c. If we vforked however, any
422 breakpoint inserted in the parent is visible in the
423 child, even those added while stopped in a vfork
424 catchpoint. This will remove the breakpoints from the
425 parent also, but they'll be reinserted below. */
428 /* keep breakpoints list in sync. */
429 remove_breakpoints_pid (ptid_get_pid (inferior_ptid));
432 if (info_verbose || debug_linux_nat)
434 target_terminal_ours ();
435 fprintf_filtered (gdb_stdlog,
436 "Detaching after fork from "
437 "child process %d.\n",
441 old_chain = save_inferior_ptid ();
442 inferior_ptid = ptid_build (child_pid, child_pid, 0);
444 child_lp = add_lwp (inferior_ptid);
445 child_lp->stopped = 1;
446 child_lp->last_resume_kind = resume_stop;
447 make_cleanup (delete_lwp_cleanup, child_lp);
449 if (linux_nat_prepare_to_resume != NULL)
450 linux_nat_prepare_to_resume (child_lp);
452 /* When debugging an inferior in an architecture that supports
453 hardware single stepping on a kernel without commit
454 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
455 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
456 set if the parent process had them set.
457 To work around this, single step the child process
458 once before detaching to clear the flags. */
460 if (!gdbarch_software_single_step_p (target_thread_architecture
465 linux_disable_event_reporting (child_pid);
466 if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
467 perror_with_name (_("Couldn't do single step"));
468 if (my_waitpid (child_pid, &status, 0) < 0)
469 perror_with_name (_("Couldn't wait vfork process"));
472 if (WIFSTOPPED (status))
473 ptrace (PTRACE_DETACH, child_pid, 0, WSTOPSIG (status));
475 do_cleanups (old_chain);
479 struct inferior *parent_inf, *child_inf;
480 struct cleanup *old_chain;
482 /* Add process to GDB's tables. */
483 child_inf = add_inferior (child_pid);
485 parent_inf = current_inferior ();
486 child_inf->attach_flag = parent_inf->attach_flag;
487 copy_terminal_info (child_inf, parent_inf);
488 child_inf->gdbarch = parent_inf->gdbarch;
489 copy_inferior_target_desc_info (child_inf, parent_inf);
491 old_chain = save_inferior_ptid ();
492 save_current_program_space ();
494 inferior_ptid = ptid_build (child_pid, child_pid, 0);
495 add_thread (inferior_ptid);
496 child_lp = add_lwp (inferior_ptid);
497 child_lp->stopped = 1;
498 child_lp->last_resume_kind = resume_stop;
499 child_inf->symfile_flags = SYMFILE_NO_READ;
501 /* If this is a vfork child, then the address-space is
502 shared with the parent. */
505 child_inf->pspace = parent_inf->pspace;
506 child_inf->aspace = parent_inf->aspace;
508 /* The parent will be frozen until the child is done
509 with the shared region. Keep track of the
511 child_inf->vfork_parent = parent_inf;
512 child_inf->pending_detach = 0;
513 parent_inf->vfork_child = child_inf;
514 parent_inf->pending_detach = 0;
518 child_inf->aspace = new_address_space ();
519 child_inf->pspace = add_program_space (child_inf->aspace);
520 child_inf->removable = 1;
521 set_current_program_space (child_inf->pspace);
522 clone_program_space (child_inf->pspace, parent_inf->pspace);
524 /* Let the shared library layer (solib-svr4) learn about
525 this new process, relocate the cloned exec, pull in
526 shared libraries, and install the solib event
527 breakpoint. If a "cloned-VM" event was propagated
528 better throughout the core, this wouldn't be
530 solib_create_inferior_hook (0);
533 /* Let the thread_db layer learn about this new process. */
534 check_for_thread_db ();
536 do_cleanups (old_chain);
541 struct lwp_info *parent_lp;
542 struct inferior *parent_inf;
544 parent_inf = current_inferior ();
546 /* If we detached from the child, then we have to be careful
547 to not insert breakpoints in the parent until the child
548 is done with the shared memory region. However, if we're
549 staying attached to the child, then we can and should
550 insert breakpoints, so that we can debug it. A
551 subsequent child exec or exit is enough to know when does
552 the child stops using the parent's address space. */
553 parent_inf->waiting_for_vfork_done = detach_fork;
554 parent_inf->pspace->breakpoints_not_allowed = detach_fork;
556 parent_lp = find_lwp_pid (pid_to_ptid (parent_pid));
557 gdb_assert (linux_supports_tracefork () >= 0);
559 if (linux_supports_tracevforkdone ())
562 fprintf_unfiltered (gdb_stdlog,
563 "LCFF: waiting for VFORK_DONE on %d\n",
565 parent_lp->stopped = 1;
567 /* We'll handle the VFORK_DONE event like any other
568 event, in target_wait. */
572 /* We can't insert breakpoints until the child has
573 finished with the shared memory region. We need to
574 wait until that happens. Ideal would be to just
576 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
577 - waitpid (parent_pid, &status, __WALL);
578 However, most architectures can't handle a syscall
579 being traced on the way out if it wasn't traced on
582 We might also think to loop, continuing the child
583 until it exits or gets a SIGTRAP. One problem is
584 that the child might call ptrace with PTRACE_TRACEME.
586 There's no simple and reliable way to figure out when
587 the vforked child will be done with its copy of the
588 shared memory. We could step it out of the syscall,
589 two instructions, let it go, and then single-step the
590 parent once. When we have hardware single-step, this
591 would work; with software single-step it could still
592 be made to work but we'd have to be able to insert
593 single-step breakpoints in the child, and we'd have
594 to insert -just- the single-step breakpoint in the
595 parent. Very awkward.
597 In the end, the best we can do is to make sure it
598 runs for a little while. Hopefully it will be out of
599 range of any breakpoints we reinsert. Usually this
600 is only the single-step breakpoint at vfork's return
604 fprintf_unfiltered (gdb_stdlog,
605 "LCFF: no VFORK_DONE "
606 "support, sleeping a bit\n");
610 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
611 and leave it pending. The next linux_nat_resume call
612 will notice a pending event, and bypasses actually
613 resuming the inferior. */
614 parent_lp->status = 0;
615 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
616 parent_lp->stopped = 1;
618 /* If we're in async mode, need to tell the event loop
619 there's something here to process. */
620 if (target_can_async_p ())
627 struct inferior *parent_inf, *child_inf;
628 struct lwp_info *child_lp;
629 struct program_space *parent_pspace;
631 if (info_verbose || debug_linux_nat)
633 target_terminal_ours ();
635 fprintf_filtered (gdb_stdlog,
636 _("Attaching after process %d "
637 "vfork to child process %d.\n"),
638 parent_pid, child_pid);
640 fprintf_filtered (gdb_stdlog,
641 _("Attaching after process %d "
642 "fork to child process %d.\n"),
643 parent_pid, child_pid);
646 /* Add the new inferior first, so that the target_detach below
647 doesn't unpush the target. */
649 child_inf = add_inferior (child_pid);
651 parent_inf = current_inferior ();
652 child_inf->attach_flag = parent_inf->attach_flag;
653 copy_terminal_info (child_inf, parent_inf);
654 child_inf->gdbarch = parent_inf->gdbarch;
655 copy_inferior_target_desc_info (child_inf, parent_inf);
657 parent_pspace = parent_inf->pspace;
659 /* If we're vforking, we want to hold on to the parent until the
660 child exits or execs. At child exec or exit time we can
661 remove the old breakpoints from the parent and detach or
662 resume debugging it. Otherwise, detach the parent now; we'll
663 want to reuse it's program/address spaces, but we can't set
664 them to the child before removing breakpoints from the
665 parent, otherwise, the breakpoints module could decide to
666 remove breakpoints from the wrong process (since they'd be
667 assigned to the same address space). */
671 gdb_assert (child_inf->vfork_parent == NULL);
672 gdb_assert (parent_inf->vfork_child == NULL);
673 child_inf->vfork_parent = parent_inf;
674 child_inf->pending_detach = 0;
675 parent_inf->vfork_child = child_inf;
676 parent_inf->pending_detach = detach_fork;
677 parent_inf->waiting_for_vfork_done = 0;
679 else if (detach_fork)
680 target_detach (NULL, 0);
682 /* Note that the detach above makes PARENT_INF dangling. */
684 /* Add the child thread to the appropriate lists, and switch to
685 this new thread, before cloning the program space, and
686 informing the solib layer about this new process. */
688 inferior_ptid = ptid_build (child_pid, child_pid, 0);
689 add_thread (inferior_ptid);
690 child_lp = add_lwp (inferior_ptid);
691 child_lp->stopped = 1;
692 child_lp->last_resume_kind = resume_stop;
694 /* If this is a vfork child, then the address-space is shared
695 with the parent. If we detached from the parent, then we can
696 reuse the parent's program/address spaces. */
697 if (has_vforked || detach_fork)
699 child_inf->pspace = parent_pspace;
700 child_inf->aspace = child_inf->pspace->aspace;
704 child_inf->aspace = new_address_space ();
705 child_inf->pspace = add_program_space (child_inf->aspace);
706 child_inf->removable = 1;
707 child_inf->symfile_flags = SYMFILE_NO_READ;
708 set_current_program_space (child_inf->pspace);
709 clone_program_space (child_inf->pspace, parent_pspace);
711 /* Let the shared library layer (solib-svr4) learn about
712 this new process, relocate the cloned exec, pull in
713 shared libraries, and install the solib event breakpoint.
714 If a "cloned-VM" event was propagated better throughout
715 the core, this wouldn't be required. */
716 solib_create_inferior_hook (0);
719 /* Let the thread_db layer learn about this new process. */
720 check_for_thread_db ();
728 linux_child_insert_fork_catchpoint (struct target_ops *self, int pid)
730 return !linux_supports_tracefork ();
734 linux_child_remove_fork_catchpoint (struct target_ops *self, int pid)
740 linux_child_insert_vfork_catchpoint (struct target_ops *self, int pid)
742 return !linux_supports_tracefork ();
746 linux_child_remove_vfork_catchpoint (struct target_ops *self, int pid)
752 linux_child_insert_exec_catchpoint (struct target_ops *self, int pid)
754 return !linux_supports_tracefork ();
758 linux_child_remove_exec_catchpoint (struct target_ops *self, int pid)
764 linux_child_set_syscall_catchpoint (struct target_ops *self,
765 int pid, int needed, int any_count,
766 int table_size, int *table)
768 if (!linux_supports_tracesysgood ())
771 /* On GNU/Linux, we ignore the arguments. It means that we only
772 enable the syscall catchpoints, but do not disable them.
774 Also, we do not use the `table' information because we do not
775 filter system calls here. We let GDB do the logic for us. */
779 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
780 are processes sharing the same VM space. A multi-threaded process
781 is basically a group of such processes. However, such a grouping
782 is almost entirely a user-space issue; the kernel doesn't enforce
783 such a grouping at all (this might change in the future). In
784 general, we'll rely on the threads library (i.e. the GNU/Linux
785 Threads library) to provide such a grouping.
787 It is perfectly well possible to write a multi-threaded application
788 without the assistance of a threads library, by using the clone
789 system call directly. This module should be able to give some
790 rudimentary support for debugging such applications if developers
791 specify the CLONE_PTRACE flag in the clone system call, and are
792 using the Linux kernel 2.4 or above.
794 Note that there are some peculiarities in GNU/Linux that affect
797 - In general one should specify the __WCLONE flag to waitpid in
798 order to make it report events for any of the cloned processes
799 (and leave it out for the initial process). However, if a cloned
800 process has exited the exit status is only reported if the
801 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
802 we cannot use it since GDB must work on older systems too.
804 - When a traced, cloned process exits and is waited for by the
805 debugger, the kernel reassigns it to the original parent and
806 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
807 library doesn't notice this, which leads to the "zombie problem":
808 When debugged a multi-threaded process that spawns a lot of
809 threads will run out of processes, even if the threads exit,
810 because the "zombies" stay around. */
812 /* List of known LWPs. */
813 struct lwp_info *lwp_list;
816 /* Original signal mask. */
817 static sigset_t normal_mask;
819 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
820 _initialize_linux_nat. */
821 static sigset_t suspend_mask;
823 /* Signals to block to make that sigsuspend work. */
824 static sigset_t blocked_mask;
826 /* SIGCHLD action. */
827 struct sigaction sigchld_action;
829 /* Block child signals (SIGCHLD and linux threads signals), and store
830 the previous mask in PREV_MASK. */
833 block_child_signals (sigset_t *prev_mask)
835 /* Make sure SIGCHLD is blocked. */
836 if (!sigismember (&blocked_mask, SIGCHLD))
837 sigaddset (&blocked_mask, SIGCHLD);
839 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
842 /* Restore child signals mask, previously returned by
843 block_child_signals. */
846 restore_child_signals_mask (sigset_t *prev_mask)
848 sigprocmask (SIG_SETMASK, prev_mask, NULL);
851 /* Mask of signals to pass directly to the inferior. */
852 static sigset_t pass_mask;
854 /* Update signals to pass to the inferior. */
856 linux_nat_pass_signals (struct target_ops *self,
857 int numsigs, unsigned char *pass_signals)
861 sigemptyset (&pass_mask);
863 for (signo = 1; signo < NSIG; signo++)
865 int target_signo = gdb_signal_from_host (signo);
866 if (target_signo < numsigs && pass_signals[target_signo])
867 sigaddset (&pass_mask, signo);
873 /* Prototypes for local functions. */
874 static int stop_wait_callback (struct lwp_info *lp, void *data);
875 static int linux_thread_alive (ptid_t ptid);
876 static char *linux_child_pid_to_exec_file (struct target_ops *self, int pid);
880 /* Destroy and free LP. */
883 lwp_free (struct lwp_info *lp)
885 xfree (lp->arch_private);
889 /* Remove all LWPs belong to PID from the lwp list. */
892 purge_lwp_list (int pid)
894 struct lwp_info *lp, *lpprev, *lpnext;
898 for (lp = lwp_list; lp; lp = lpnext)
902 if (ptid_get_pid (lp->ptid) == pid)
907 lpprev->next = lp->next;
916 /* Add the LWP specified by PTID to the list. PTID is the first LWP
917 in the process. Return a pointer to the structure describing the
920 This differs from add_lwp in that we don't let the arch specific
921 bits know about this new thread. Current clients of this callback
922 take the opportunity to install watchpoints in the new thread, and
923 we shouldn't do that for the first thread. If we're spawning a
924 child ("run"), the thread executes the shell wrapper first, and we
925 shouldn't touch it until it execs the program we want to debug.
926 For "attach", it'd be okay to call the callback, but it's not
927 necessary, because watchpoints can't yet have been inserted into
930 static struct lwp_info *
931 add_initial_lwp (ptid_t ptid)
935 gdb_assert (ptid_lwp_p (ptid));
937 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
939 memset (lp, 0, sizeof (struct lwp_info));
941 lp->last_resume_kind = resume_continue;
942 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
953 /* Add the LWP specified by PID to the list. Return a pointer to the
954 structure describing the new LWP. The LWP should already be
957 static struct lwp_info *
958 add_lwp (ptid_t ptid)
962 lp = add_initial_lwp (ptid);
964 /* Let the arch specific bits know about this new thread. Current
965 clients of this callback take the opportunity to install
966 watchpoints in the new thread. We don't do this for the first
967 thread though. See add_initial_lwp. */
968 if (linux_nat_new_thread != NULL)
969 linux_nat_new_thread (lp);
974 /* Remove the LWP specified by PID from the list. */
977 delete_lwp (ptid_t ptid)
979 struct lwp_info *lp, *lpprev;
983 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
984 if (ptid_equal (lp->ptid, ptid))
991 lpprev->next = lp->next;
998 /* Return a pointer to the structure describing the LWP corresponding
999 to PID. If no corresponding LWP could be found, return NULL. */
1001 static struct lwp_info *
1002 find_lwp_pid (ptid_t ptid)
1004 struct lwp_info *lp;
1007 if (ptid_lwp_p (ptid))
1008 lwp = ptid_get_lwp (ptid);
1010 lwp = ptid_get_pid (ptid);
1012 for (lp = lwp_list; lp; lp = lp->next)
1013 if (lwp == ptid_get_lwp (lp->ptid))
1019 /* Call CALLBACK with its second argument set to DATA for every LWP in
1020 the list. If CALLBACK returns 1 for a particular LWP, return a
1021 pointer to the structure describing that LWP immediately.
1022 Otherwise return NULL. */
1025 iterate_over_lwps (ptid_t filter,
1026 int (*callback) (struct lwp_info *, void *),
1029 struct lwp_info *lp, *lpnext;
1031 for (lp = lwp_list; lp; lp = lpnext)
1035 if (ptid_match (lp->ptid, filter))
1037 if ((*callback) (lp, data))
1045 /* Update our internal state when changing from one checkpoint to
1046 another indicated by NEW_PTID. We can only switch single-threaded
1047 applications, so we only create one new LWP, and the previous list
1051 linux_nat_switch_fork (ptid_t new_ptid)
1053 struct lwp_info *lp;
1055 purge_lwp_list (ptid_get_pid (inferior_ptid));
1057 lp = add_lwp (new_ptid);
1060 /* This changes the thread's ptid while preserving the gdb thread
1061 num. Also changes the inferior pid, while preserving the
1063 thread_change_ptid (inferior_ptid, new_ptid);
1065 /* We've just told GDB core that the thread changed target id, but,
1066 in fact, it really is a different thread, with different register
1068 registers_changed ();
1071 /* Handle the exit of a single thread LP. */
1074 exit_lwp (struct lwp_info *lp)
1076 struct thread_info *th = find_thread_ptid (lp->ptid);
1080 if (print_thread_events)
1081 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
1083 delete_thread (lp->ptid);
1086 delete_lwp (lp->ptid);
1089 /* Wait for the LWP specified by LP, which we have just attached to.
1090 Returns a wait status for that LWP, to cache. */
1093 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
1096 pid_t new_pid, pid = ptid_get_lwp (ptid);
1099 if (linux_proc_pid_is_stopped (pid))
1101 if (debug_linux_nat)
1102 fprintf_unfiltered (gdb_stdlog,
1103 "LNPAW: Attaching to a stopped process\n");
1105 /* The process is definitely stopped. It is in a job control
1106 stop, unless the kernel predates the TASK_STOPPED /
1107 TASK_TRACED distinction, in which case it might be in a
1108 ptrace stop. Make sure it is in a ptrace stop; from there we
1109 can kill it, signal it, et cetera.
1111 First make sure there is a pending SIGSTOP. Since we are
1112 already attached, the process can not transition from stopped
1113 to running without a PTRACE_CONT; so we know this signal will
1114 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1115 probably already in the queue (unless this kernel is old
1116 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1117 is not an RT signal, it can only be queued once. */
1118 kill_lwp (pid, SIGSTOP);
1120 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1121 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1122 ptrace (PTRACE_CONT, pid, 0, 0);
1125 /* Make sure the initial process is stopped. The user-level threads
1126 layer might want to poke around in the inferior, and that won't
1127 work if things haven't stabilized yet. */
1128 new_pid = my_waitpid (pid, &status, 0);
1129 if (new_pid == -1 && errno == ECHILD)
1132 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
1134 /* Try again with __WCLONE to check cloned processes. */
1135 new_pid = my_waitpid (pid, &status, __WCLONE);
1139 gdb_assert (pid == new_pid);
1141 if (!WIFSTOPPED (status))
1143 /* The pid we tried to attach has apparently just exited. */
1144 if (debug_linux_nat)
1145 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
1146 pid, status_to_str (status));
1150 if (WSTOPSIG (status) != SIGSTOP)
1153 if (debug_linux_nat)
1154 fprintf_unfiltered (gdb_stdlog,
1155 "LNPAW: Received %s after attaching\n",
1156 status_to_str (status));
1162 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1163 the new LWP could not be attached, or 1 if we're already auto
1164 attached to this thread, but haven't processed the
1165 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1166 its existance, without considering it an error. */
1169 lin_lwp_attach_lwp (ptid_t ptid)
1171 struct lwp_info *lp;
1174 gdb_assert (ptid_lwp_p (ptid));
1176 lp = find_lwp_pid (ptid);
1177 lwpid = ptid_get_lwp (ptid);
1179 /* We assume that we're already attached to any LWP that has an id
1180 equal to the overall process id, and to any LWP that is already
1181 in our list of LWPs. If we're not seeing exit events from threads
1182 and we've had PID wraparound since we last tried to stop all threads,
1183 this assumption might be wrong; fortunately, this is very unlikely
1185 if (lwpid != ptid_get_pid (ptid) && lp == NULL)
1187 int status, cloned = 0, signalled = 0;
1189 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1191 if (linux_supports_tracefork ())
1193 /* If we haven't stopped all threads when we get here,
1194 we may have seen a thread listed in thread_db's list,
1195 but not processed the PTRACE_EVENT_CLONE yet. If
1196 that's the case, ignore this new thread, and let
1197 normal event handling discover it later. */
1198 if (in_pid_list_p (stopped_pids, lwpid))
1200 /* We've already seen this thread stop, but we
1201 haven't seen the PTRACE_EVENT_CLONE extended
1210 /* See if we've got a stop for this new child
1211 pending. If so, we're already attached. */
1212 new_pid = my_waitpid (lwpid, &status, WNOHANG);
1213 if (new_pid == -1 && errno == ECHILD)
1214 new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
1217 if (WIFSTOPPED (status))
1218 add_to_pid_list (&stopped_pids, lwpid, status);
1224 /* If we fail to attach to the thread, issue a warning,
1225 but continue. One way this can happen is if thread
1226 creation is interrupted; as of Linux kernel 2.6.19, a
1227 bug may place threads in the thread list and then fail
1229 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1230 safe_strerror (errno));
1234 if (debug_linux_nat)
1235 fprintf_unfiltered (gdb_stdlog,
1236 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1237 target_pid_to_str (ptid));
1239 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1240 if (!WIFSTOPPED (status))
1243 lp = add_lwp (ptid);
1245 lp->cloned = cloned;
1246 lp->signalled = signalled;
1247 if (WSTOPSIG (status) != SIGSTOP)
1250 lp->status = status;
1253 target_post_attach (ptid_get_lwp (lp->ptid));
1255 if (debug_linux_nat)
1257 fprintf_unfiltered (gdb_stdlog,
1258 "LLAL: waitpid %s received %s\n",
1259 target_pid_to_str (ptid),
1260 status_to_str (status));
1265 /* We assume that the LWP representing the original process is
1266 already stopped. Mark it as stopped in the data structure
1267 that the GNU/linux ptrace layer uses to keep track of
1268 threads. Note that this won't have already been done since
1269 the main thread will have, we assume, been stopped by an
1270 attach from a different layer. */
1272 lp = add_lwp (ptid);
1276 lp->last_resume_kind = resume_stop;
1281 linux_nat_create_inferior (struct target_ops *ops,
1282 char *exec_file, char *allargs, char **env,
1285 #ifdef HAVE_PERSONALITY
1286 int personality_orig = 0, personality_set = 0;
1287 #endif /* HAVE_PERSONALITY */
1289 /* The fork_child mechanism is synchronous and calls target_wait, so
1290 we have to mask the async mode. */
1292 #ifdef HAVE_PERSONALITY
1293 if (disable_randomization)
1296 personality_orig = personality (0xffffffff);
1297 if (errno == 0 && !(personality_orig & ADDR_NO_RANDOMIZE))
1299 personality_set = 1;
1300 personality (personality_orig | ADDR_NO_RANDOMIZE);
1302 if (errno != 0 || (personality_set
1303 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE)))
1304 warning (_("Error disabling address space randomization: %s"),
1305 safe_strerror (errno));
1307 #endif /* HAVE_PERSONALITY */
1309 /* Make sure we report all signals during startup. */
1310 linux_nat_pass_signals (ops, 0, NULL);
1312 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1314 #ifdef HAVE_PERSONALITY
1315 if (personality_set)
1318 personality (personality_orig);
1320 warning (_("Error restoring address space randomization: %s"),
1321 safe_strerror (errno));
1323 #endif /* HAVE_PERSONALITY */
1327 linux_nat_attach (struct target_ops *ops, const char *args, int from_tty)
1329 struct lwp_info *lp;
1332 volatile struct gdb_exception ex;
1334 /* Make sure we report all signals during attach. */
1335 linux_nat_pass_signals (ops, 0, NULL);
1337 TRY_CATCH (ex, RETURN_MASK_ERROR)
1339 linux_ops->to_attach (ops, args, from_tty);
1343 pid_t pid = parse_pid_to_attach (args);
1344 struct buffer buffer;
1345 char *message, *buffer_s;
1347 message = xstrdup (ex.message);
1348 make_cleanup (xfree, message);
1350 buffer_init (&buffer);
1351 linux_ptrace_attach_fail_reason (pid, &buffer);
1353 buffer_grow_str0 (&buffer, "");
1354 buffer_s = buffer_finish (&buffer);
1355 make_cleanup (xfree, buffer_s);
1357 if (*buffer_s != '\0')
1358 throw_error (ex.error, "warning: %s\n%s", buffer_s, message);
1360 throw_error (ex.error, "%s", message);
1363 /* The ptrace base target adds the main thread with (pid,0,0)
1364 format. Decorate it with lwp info. */
1365 ptid = ptid_build (ptid_get_pid (inferior_ptid),
1366 ptid_get_pid (inferior_ptid),
1368 thread_change_ptid (inferior_ptid, ptid);
1370 /* Add the initial process as the first LWP to the list. */
1371 lp = add_initial_lwp (ptid);
1373 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1375 if (!WIFSTOPPED (status))
1377 if (WIFEXITED (status))
1379 int exit_code = WEXITSTATUS (status);
1381 target_terminal_ours ();
1382 target_mourn_inferior ();
1384 error (_("Unable to attach: program exited normally."));
1386 error (_("Unable to attach: program exited with code %d."),
1389 else if (WIFSIGNALED (status))
1391 enum gdb_signal signo;
1393 target_terminal_ours ();
1394 target_mourn_inferior ();
1396 signo = gdb_signal_from_host (WTERMSIG (status));
1397 error (_("Unable to attach: program terminated with signal "
1399 gdb_signal_to_name (signo),
1400 gdb_signal_to_string (signo));
1403 internal_error (__FILE__, __LINE__,
1404 _("unexpected status %d for PID %ld"),
1405 status, (long) ptid_get_lwp (ptid));
1410 /* Save the wait status to report later. */
1412 if (debug_linux_nat)
1413 fprintf_unfiltered (gdb_stdlog,
1414 "LNA: waitpid %ld, saving status %s\n",
1415 (long) ptid_get_pid (lp->ptid), status_to_str (status));
1417 lp->status = status;
1419 if (target_can_async_p ())
1420 target_async (inferior_event_handler, 0);
1423 /* Get pending status of LP. */
1425 get_pending_status (struct lwp_info *lp, int *status)
1427 enum gdb_signal signo = GDB_SIGNAL_0;
1429 /* If we paused threads momentarily, we may have stored pending
1430 events in lp->status or lp->waitstatus (see stop_wait_callback),
1431 and GDB core hasn't seen any signal for those threads.
1432 Otherwise, the last signal reported to the core is found in the
1433 thread object's stop_signal.
1435 There's a corner case that isn't handled here at present. Only
1436 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1437 stop_signal make sense as a real signal to pass to the inferior.
1438 Some catchpoint related events, like
1439 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1440 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1441 those traps are debug API (ptrace in our case) related and
1442 induced; the inferior wouldn't see them if it wasn't being
1443 traced. Hence, we should never pass them to the inferior, even
1444 when set to pass state. Since this corner case isn't handled by
1445 infrun.c when proceeding with a signal, for consistency, neither
1446 do we handle it here (or elsewhere in the file we check for
1447 signal pass state). Normally SIGTRAP isn't set to pass state, so
1448 this is really a corner case. */
1450 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1451 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1452 else if (lp->status)
1453 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1454 else if (non_stop && !is_executing (lp->ptid))
1456 struct thread_info *tp = find_thread_ptid (lp->ptid);
1458 signo = tp->suspend.stop_signal;
1462 struct target_waitstatus last;
1465 get_last_target_status (&last_ptid, &last);
1467 if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
1469 struct thread_info *tp = find_thread_ptid (lp->ptid);
1471 signo = tp->suspend.stop_signal;
1477 if (signo == GDB_SIGNAL_0)
1479 if (debug_linux_nat)
1480 fprintf_unfiltered (gdb_stdlog,
1481 "GPT: lwp %s has no pending signal\n",
1482 target_pid_to_str (lp->ptid));
1484 else if (!signal_pass_state (signo))
1486 if (debug_linux_nat)
1487 fprintf_unfiltered (gdb_stdlog,
1488 "GPT: lwp %s had signal %s, "
1489 "but it is in no pass state\n",
1490 target_pid_to_str (lp->ptid),
1491 gdb_signal_to_string (signo));
1495 *status = W_STOPCODE (gdb_signal_to_host (signo));
1497 if (debug_linux_nat)
1498 fprintf_unfiltered (gdb_stdlog,
1499 "GPT: lwp %s has pending signal %s\n",
1500 target_pid_to_str (lp->ptid),
1501 gdb_signal_to_string (signo));
1508 detach_callback (struct lwp_info *lp, void *data)
1510 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1512 if (debug_linux_nat && lp->status)
1513 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1514 strsignal (WSTOPSIG (lp->status)),
1515 target_pid_to_str (lp->ptid));
1517 /* If there is a pending SIGSTOP, get rid of it. */
1520 if (debug_linux_nat)
1521 fprintf_unfiltered (gdb_stdlog,
1522 "DC: Sending SIGCONT to %s\n",
1523 target_pid_to_str (lp->ptid));
1525 kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
1529 /* We don't actually detach from the LWP that has an id equal to the
1530 overall process id just yet. */
1531 if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
1535 /* Pass on any pending signal for this LWP. */
1536 get_pending_status (lp, &status);
1538 if (linux_nat_prepare_to_resume != NULL)
1539 linux_nat_prepare_to_resume (lp);
1541 if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
1542 WSTOPSIG (status)) < 0)
1543 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1544 safe_strerror (errno));
1546 if (debug_linux_nat)
1547 fprintf_unfiltered (gdb_stdlog,
1548 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1549 target_pid_to_str (lp->ptid),
1550 strsignal (WSTOPSIG (status)));
1552 delete_lwp (lp->ptid);
1559 linux_nat_detach (struct target_ops *ops, const char *args, int from_tty)
1563 struct lwp_info *main_lwp;
1565 pid = ptid_get_pid (inferior_ptid);
1567 /* Don't unregister from the event loop, as there may be other
1568 inferiors running. */
1570 /* Stop all threads before detaching. ptrace requires that the
1571 thread is stopped to sucessfully detach. */
1572 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1573 /* ... and wait until all of them have reported back that
1574 they're no longer running. */
1575 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1577 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1579 /* Only the initial process should be left right now. */
1580 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
1582 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1584 /* Pass on any pending signal for the last LWP. */
1585 if ((args == NULL || *args == '\0')
1586 && get_pending_status (main_lwp, &status) != -1
1587 && WIFSTOPPED (status))
1591 /* Put the signal number in ARGS so that inf_ptrace_detach will
1592 pass it along with PTRACE_DETACH. */
1594 xsnprintf (tem, 8, "%d", (int) WSTOPSIG (status));
1596 if (debug_linux_nat)
1597 fprintf_unfiltered (gdb_stdlog,
1598 "LND: Sending signal %s to %s\n",
1600 target_pid_to_str (main_lwp->ptid));
1603 if (linux_nat_prepare_to_resume != NULL)
1604 linux_nat_prepare_to_resume (main_lwp);
1605 delete_lwp (main_lwp->ptid);
1607 if (forks_exist_p ())
1609 /* Multi-fork case. The current inferior_ptid is being detached
1610 from, but there are other viable forks to debug. Detach from
1611 the current fork, and context-switch to the first
1613 linux_fork_detach (args, from_tty);
1616 linux_ops->to_detach (ops, args, from_tty);
1622 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1626 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
1628 if (inf->vfork_child != NULL)
1630 if (debug_linux_nat)
1631 fprintf_unfiltered (gdb_stdlog,
1632 "RC: Not resuming %s (vfork parent)\n",
1633 target_pid_to_str (lp->ptid));
1635 else if (lp->status == 0
1636 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
1638 if (debug_linux_nat)
1639 fprintf_unfiltered (gdb_stdlog,
1640 "RC: Resuming sibling %s, %s, %s\n",
1641 target_pid_to_str (lp->ptid),
1642 (signo != GDB_SIGNAL_0
1643 ? strsignal (gdb_signal_to_host (signo))
1645 step ? "step" : "resume");
1647 if (linux_nat_prepare_to_resume != NULL)
1648 linux_nat_prepare_to_resume (lp);
1649 linux_ops->to_resume (linux_ops,
1650 pid_to_ptid (ptid_get_lwp (lp->ptid)),
1654 lp->stopped_by_watchpoint = 0;
1658 if (debug_linux_nat)
1659 fprintf_unfiltered (gdb_stdlog,
1660 "RC: Not resuming sibling %s (has pending)\n",
1661 target_pid_to_str (lp->ptid));
1666 if (debug_linux_nat)
1667 fprintf_unfiltered (gdb_stdlog,
1668 "RC: Not resuming sibling %s (not stopped)\n",
1669 target_pid_to_str (lp->ptid));
1673 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1674 Resume LWP with the last stop signal, if it is in pass state. */
1677 linux_nat_resume_callback (struct lwp_info *lp, void *except)
1679 enum gdb_signal signo = GDB_SIGNAL_0;
1686 struct thread_info *thread;
1688 thread = find_thread_ptid (lp->ptid);
1691 if (signal_pass_state (thread->suspend.stop_signal))
1692 signo = thread->suspend.stop_signal;
1693 thread->suspend.stop_signal = GDB_SIGNAL_0;
1697 resume_lwp (lp, 0, signo);
1702 resume_clear_callback (struct lwp_info *lp, void *data)
1705 lp->last_resume_kind = resume_stop;
1710 resume_set_callback (struct lwp_info *lp, void *data)
1713 lp->last_resume_kind = resume_continue;
1718 linux_nat_resume (struct target_ops *ops,
1719 ptid_t ptid, int step, enum gdb_signal signo)
1721 struct lwp_info *lp;
1724 if (debug_linux_nat)
1725 fprintf_unfiltered (gdb_stdlog,
1726 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1727 step ? "step" : "resume",
1728 target_pid_to_str (ptid),
1729 (signo != GDB_SIGNAL_0
1730 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1731 target_pid_to_str (inferior_ptid));
1733 /* A specific PTID means `step only this process id'. */
1734 resume_many = (ptid_equal (minus_one_ptid, ptid)
1735 || ptid_is_pid (ptid));
1737 /* Mark the lwps we're resuming as resumed. */
1738 iterate_over_lwps (ptid, resume_set_callback, NULL);
1740 /* See if it's the current inferior that should be handled
1743 lp = find_lwp_pid (inferior_ptid);
1745 lp = find_lwp_pid (ptid);
1746 gdb_assert (lp != NULL);
1748 /* Remember if we're stepping. */
1750 lp->last_resume_kind = step ? resume_step : resume_continue;
1752 /* If we have a pending wait status for this thread, there is no
1753 point in resuming the process. But first make sure that
1754 linux_nat_wait won't preemptively handle the event - we
1755 should never take this short-circuit if we are going to
1756 leave LP running, since we have skipped resuming all the
1757 other threads. This bit of code needs to be synchronized
1758 with linux_nat_wait. */
1760 if (lp->status && WIFSTOPPED (lp->status))
1763 && WSTOPSIG (lp->status)
1764 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1766 if (debug_linux_nat)
1767 fprintf_unfiltered (gdb_stdlog,
1768 "LLR: Not short circuiting for ignored "
1769 "status 0x%x\n", lp->status);
1771 /* FIXME: What should we do if we are supposed to continue
1772 this thread with a signal? */
1773 gdb_assert (signo == GDB_SIGNAL_0);
1774 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1779 if (lp->status || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1781 /* FIXME: What should we do if we are supposed to continue
1782 this thread with a signal? */
1783 gdb_assert (signo == GDB_SIGNAL_0);
1785 if (debug_linux_nat)
1786 fprintf_unfiltered (gdb_stdlog,
1787 "LLR: Short circuiting for status 0x%x\n",
1790 if (target_can_async_p ())
1792 target_async (inferior_event_handler, 0);
1793 /* Tell the event loop we have something to process. */
1800 iterate_over_lwps (ptid, linux_nat_resume_callback, lp);
1802 /* Convert to something the lower layer understands. */
1803 ptid = pid_to_ptid (ptid_get_lwp (lp->ptid));
1805 if (linux_nat_prepare_to_resume != NULL)
1806 linux_nat_prepare_to_resume (lp);
1807 linux_ops->to_resume (linux_ops, ptid, step, signo);
1808 lp->stopped_by_watchpoint = 0;
1811 if (debug_linux_nat)
1812 fprintf_unfiltered (gdb_stdlog,
1813 "LLR: %s %s, %s (resume event thread)\n",
1814 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1815 target_pid_to_str (ptid),
1816 (signo != GDB_SIGNAL_0
1817 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1819 if (target_can_async_p ())
1820 target_async (inferior_event_handler, 0);
1823 /* Send a signal to an LWP. */
1826 kill_lwp (int lwpid, int signo)
1828 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1829 fails, then we are not using nptl threads and we should be using kill. */
1831 #ifdef HAVE_TKILL_SYSCALL
1833 static int tkill_failed;
1840 ret = syscall (__NR_tkill, lwpid, signo);
1841 if (errno != ENOSYS)
1848 return kill (lwpid, signo);
1851 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1852 event, check if the core is interested in it: if not, ignore the
1853 event, and keep waiting; otherwise, we need to toggle the LWP's
1854 syscall entry/exit status, since the ptrace event itself doesn't
1855 indicate it, and report the trap to higher layers. */
1858 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1860 struct target_waitstatus *ourstatus = &lp->waitstatus;
1861 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1862 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1866 /* If we're stopping threads, there's a SIGSTOP pending, which
1867 makes it so that the LWP reports an immediate syscall return,
1868 followed by the SIGSTOP. Skip seeing that "return" using
1869 PTRACE_CONT directly, and let stop_wait_callback collect the
1870 SIGSTOP. Later when the thread is resumed, a new syscall
1871 entry event. If we didn't do this (and returned 0), we'd
1872 leave a syscall entry pending, and our caller, by using
1873 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1874 itself. Later, when the user re-resumes this LWP, we'd see
1875 another syscall entry event and we'd mistake it for a return.
1877 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1878 (leaving immediately with LWP->signalled set, without issuing
1879 a PTRACE_CONT), it would still be problematic to leave this
1880 syscall enter pending, as later when the thread is resumed,
1881 it would then see the same syscall exit mentioned above,
1882 followed by the delayed SIGSTOP, while the syscall didn't
1883 actually get to execute. It seems it would be even more
1884 confusing to the user. */
1886 if (debug_linux_nat)
1887 fprintf_unfiltered (gdb_stdlog,
1888 "LHST: ignoring syscall %d "
1889 "for LWP %ld (stopping threads), "
1890 "resuming with PTRACE_CONT for SIGSTOP\n",
1892 ptid_get_lwp (lp->ptid));
1894 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1895 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1900 if (catch_syscall_enabled ())
1902 /* Always update the entry/return state, even if this particular
1903 syscall isn't interesting to the core now. In async mode,
1904 the user could install a new catchpoint for this syscall
1905 between syscall enter/return, and we'll need to know to
1906 report a syscall return if that happens. */
1907 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1908 ? TARGET_WAITKIND_SYSCALL_RETURN
1909 : TARGET_WAITKIND_SYSCALL_ENTRY);
1911 if (catching_syscall_number (syscall_number))
1913 /* Alright, an event to report. */
1914 ourstatus->kind = lp->syscall_state;
1915 ourstatus->value.syscall_number = syscall_number;
1917 if (debug_linux_nat)
1918 fprintf_unfiltered (gdb_stdlog,
1919 "LHST: stopping for %s of syscall %d"
1922 == TARGET_WAITKIND_SYSCALL_ENTRY
1923 ? "entry" : "return",
1925 ptid_get_lwp (lp->ptid));
1929 if (debug_linux_nat)
1930 fprintf_unfiltered (gdb_stdlog,
1931 "LHST: ignoring %s of syscall %d "
1933 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1934 ? "entry" : "return",
1936 ptid_get_lwp (lp->ptid));
1940 /* If we had been syscall tracing, and hence used PT_SYSCALL
1941 before on this LWP, it could happen that the user removes all
1942 syscall catchpoints before we get to process this event.
1943 There are two noteworthy issues here:
1945 - When stopped at a syscall entry event, resuming with
1946 PT_STEP still resumes executing the syscall and reports a
1949 - Only PT_SYSCALL catches syscall enters. If we last
1950 single-stepped this thread, then this event can't be a
1951 syscall enter. If we last single-stepped this thread, this
1952 has to be a syscall exit.
1954 The points above mean that the next resume, be it PT_STEP or
1955 PT_CONTINUE, can not trigger a syscall trace event. */
1956 if (debug_linux_nat)
1957 fprintf_unfiltered (gdb_stdlog,
1958 "LHST: caught syscall event "
1959 "with no syscall catchpoints."
1960 " %d for LWP %ld, ignoring\n",
1962 ptid_get_lwp (lp->ptid));
1963 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1966 /* The core isn't interested in this event. For efficiency, avoid
1967 stopping all threads only to have the core resume them all again.
1968 Since we're not stopping threads, if we're still syscall tracing
1969 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1970 subsequent syscall. Simply resume using the inf-ptrace layer,
1971 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1973 /* Note that gdbarch_get_syscall_number may access registers, hence
1975 registers_changed ();
1976 if (linux_nat_prepare_to_resume != NULL)
1977 linux_nat_prepare_to_resume (lp);
1978 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
1979 lp->step, GDB_SIGNAL_0);
1984 /* Handle a GNU/Linux extended wait response. If we see a clone
1985 event, we need to add the new LWP to our list (and not report the
1986 trap to higher layers). This function returns non-zero if the
1987 event should be ignored and we should wait again. If STOPPING is
1988 true, the new LWP remains stopped, otherwise it is continued. */
1991 linux_handle_extended_wait (struct lwp_info *lp, int status,
1994 int pid = ptid_get_lwp (lp->ptid);
1995 struct target_waitstatus *ourstatus = &lp->waitstatus;
1996 int event = status >> 16;
1998 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
1999 || event == PTRACE_EVENT_CLONE)
2001 unsigned long new_pid;
2004 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
2006 /* If we haven't already seen the new PID stop, wait for it now. */
2007 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
2009 /* The new child has a pending SIGSTOP. We can't affect it until it
2010 hits the SIGSTOP, but we're already attached. */
2011 ret = my_waitpid (new_pid, &status,
2012 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
2014 perror_with_name (_("waiting for new child"));
2015 else if (ret != new_pid)
2016 internal_error (__FILE__, __LINE__,
2017 _("wait returned unexpected PID %d"), ret);
2018 else if (!WIFSTOPPED (status))
2019 internal_error (__FILE__, __LINE__,
2020 _("wait returned unexpected status 0x%x"), status);
2023 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
2025 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
2027 /* The arch-specific native code may need to know about new
2028 forks even if those end up never mapped to an
2030 if (linux_nat_new_fork != NULL)
2031 linux_nat_new_fork (lp, new_pid);
2034 if (event == PTRACE_EVENT_FORK
2035 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
2037 /* Handle checkpointing by linux-fork.c here as a special
2038 case. We don't want the follow-fork-mode or 'catch fork'
2039 to interfere with this. */
2041 /* This won't actually modify the breakpoint list, but will
2042 physically remove the breakpoints from the child. */
2043 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
2045 /* Retain child fork in ptrace (stopped) state. */
2046 if (!find_fork_pid (new_pid))
2049 /* Report as spurious, so that infrun doesn't want to follow
2050 this fork. We're actually doing an infcall in
2052 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
2054 /* Report the stop to the core. */
2058 if (event == PTRACE_EVENT_FORK)
2059 ourstatus->kind = TARGET_WAITKIND_FORKED;
2060 else if (event == PTRACE_EVENT_VFORK)
2061 ourstatus->kind = TARGET_WAITKIND_VFORKED;
2064 struct lwp_info *new_lp;
2066 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2068 if (debug_linux_nat)
2069 fprintf_unfiltered (gdb_stdlog,
2070 "LHEW: Got clone event "
2071 "from LWP %d, new child is LWP %ld\n",
2074 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
2076 new_lp->stopped = 1;
2078 if (WSTOPSIG (status) != SIGSTOP)
2080 /* This can happen if someone starts sending signals to
2081 the new thread before it gets a chance to run, which
2082 have a lower number than SIGSTOP (e.g. SIGUSR1).
2083 This is an unlikely case, and harder to handle for
2084 fork / vfork than for clone, so we do not try - but
2085 we handle it for clone events here. We'll send
2086 the other signal on to the thread below. */
2088 new_lp->signalled = 1;
2092 struct thread_info *tp;
2094 /* When we stop for an event in some other thread, and
2095 pull the thread list just as this thread has cloned,
2096 we'll have seen the new thread in the thread_db list
2097 before handling the CLONE event (glibc's
2098 pthread_create adds the new thread to the thread list
2099 before clone'ing, and has the kernel fill in the
2100 thread's tid on the clone call with
2101 CLONE_PARENT_SETTID). If that happened, and the core
2102 had requested the new thread to stop, we'll have
2103 killed it with SIGSTOP. But since SIGSTOP is not an
2104 RT signal, it can only be queued once. We need to be
2105 careful to not resume the LWP if we wanted it to
2106 stop. In that case, we'll leave the SIGSTOP pending.
2107 It will later be reported as GDB_SIGNAL_0. */
2108 tp = find_thread_ptid (new_lp->ptid);
2109 if (tp != NULL && tp->stop_requested)
2110 new_lp->last_resume_kind = resume_stop;
2117 /* Add the new thread to GDB's lists as soon as possible
2120 1) the frontend doesn't have to wait for a stop to
2123 2) we tag it with the correct running state. */
2125 /* If the thread_db layer is active, let it know about
2126 this new thread, and add it to GDB's list. */
2127 if (!thread_db_attach_lwp (new_lp->ptid))
2129 /* We're not using thread_db. Add it to GDB's
2131 target_post_attach (ptid_get_lwp (new_lp->ptid));
2132 add_thread (new_lp->ptid);
2137 set_running (new_lp->ptid, 1);
2138 set_executing (new_lp->ptid, 1);
2139 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2141 new_lp->last_resume_kind = resume_continue;
2147 /* We created NEW_LP so it cannot yet contain STATUS. */
2148 gdb_assert (new_lp->status == 0);
2150 /* Save the wait status to report later. */
2151 if (debug_linux_nat)
2152 fprintf_unfiltered (gdb_stdlog,
2153 "LHEW: waitpid of new LWP %ld, "
2154 "saving status %s\n",
2155 (long) ptid_get_lwp (new_lp->ptid),
2156 status_to_str (status));
2157 new_lp->status = status;
2160 /* Note the need to use the low target ops to resume, to
2161 handle resuming with PT_SYSCALL if we have syscall
2165 new_lp->resumed = 1;
2169 gdb_assert (new_lp->last_resume_kind == resume_continue);
2170 if (debug_linux_nat)
2171 fprintf_unfiltered (gdb_stdlog,
2172 "LHEW: resuming new LWP %ld\n",
2173 ptid_get_lwp (new_lp->ptid));
2174 if (linux_nat_prepare_to_resume != NULL)
2175 linux_nat_prepare_to_resume (new_lp);
2176 linux_ops->to_resume (linux_ops, pid_to_ptid (new_pid),
2178 new_lp->stopped = 0;
2182 if (debug_linux_nat)
2183 fprintf_unfiltered (gdb_stdlog,
2184 "LHEW: resuming parent LWP %d\n", pid);
2185 if (linux_nat_prepare_to_resume != NULL)
2186 linux_nat_prepare_to_resume (lp);
2187 linux_ops->to_resume (linux_ops,
2188 pid_to_ptid (ptid_get_lwp (lp->ptid)),
2197 if (event == PTRACE_EVENT_EXEC)
2199 if (debug_linux_nat)
2200 fprintf_unfiltered (gdb_stdlog,
2201 "LHEW: Got exec event from LWP %ld\n",
2202 ptid_get_lwp (lp->ptid));
2204 ourstatus->kind = TARGET_WAITKIND_EXECD;
2205 ourstatus->value.execd_pathname
2206 = xstrdup (linux_child_pid_to_exec_file (NULL, pid));
2211 if (event == PTRACE_EVENT_VFORK_DONE)
2213 if (current_inferior ()->waiting_for_vfork_done)
2215 if (debug_linux_nat)
2216 fprintf_unfiltered (gdb_stdlog,
2217 "LHEW: Got expected PTRACE_EVENT_"
2218 "VFORK_DONE from LWP %ld: stopping\n",
2219 ptid_get_lwp (lp->ptid));
2221 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2225 if (debug_linux_nat)
2226 fprintf_unfiltered (gdb_stdlog,
2227 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2228 "from LWP %ld: resuming\n",
2229 ptid_get_lwp (lp->ptid));
2230 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2234 internal_error (__FILE__, __LINE__,
2235 _("unknown ptrace event %d"), event);
2238 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2242 wait_lwp (struct lwp_info *lp)
2246 int thread_dead = 0;
2249 gdb_assert (!lp->stopped);
2250 gdb_assert (lp->status == 0);
2252 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2253 block_child_signals (&prev_mask);
2257 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2258 was right and we should just call sigsuspend. */
2260 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
2261 if (pid == -1 && errno == ECHILD)
2262 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
2263 if (pid == -1 && errno == ECHILD)
2265 /* The thread has previously exited. We need to delete it
2266 now because, for some vendor 2.4 kernels with NPTL
2267 support backported, there won't be an exit event unless
2268 it is the main thread. 2.6 kernels will report an exit
2269 event for each thread that exits, as expected. */
2271 if (debug_linux_nat)
2272 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2273 target_pid_to_str (lp->ptid));
2278 /* Bugs 10970, 12702.
2279 Thread group leader may have exited in which case we'll lock up in
2280 waitpid if there are other threads, even if they are all zombies too.
2281 Basically, we're not supposed to use waitpid this way.
2282 __WCLONE is not applicable for the leader so we can't use that.
2283 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2284 process; it gets ESRCH both for the zombie and for running processes.
2286 As a workaround, check if we're waiting for the thread group leader and
2287 if it's a zombie, and avoid calling waitpid if it is.
2289 This is racy, what if the tgl becomes a zombie right after we check?
2290 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2291 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2293 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2294 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2297 if (debug_linux_nat)
2298 fprintf_unfiltered (gdb_stdlog,
2299 "WL: Thread group leader %s vanished.\n",
2300 target_pid_to_str (lp->ptid));
2304 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2305 get invoked despite our caller had them intentionally blocked by
2306 block_child_signals. This is sensitive only to the loop of
2307 linux_nat_wait_1 and there if we get called my_waitpid gets called
2308 again before it gets to sigsuspend so we can safely let the handlers
2309 get executed here. */
2311 sigsuspend (&suspend_mask);
2314 restore_child_signals_mask (&prev_mask);
2318 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2320 if (debug_linux_nat)
2322 fprintf_unfiltered (gdb_stdlog,
2323 "WL: waitpid %s received %s\n",
2324 target_pid_to_str (lp->ptid),
2325 status_to_str (status));
2328 /* Check if the thread has exited. */
2329 if (WIFEXITED (status) || WIFSIGNALED (status))
2332 if (debug_linux_nat)
2333 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2334 target_pid_to_str (lp->ptid));
2344 gdb_assert (WIFSTOPPED (status));
2347 /* Handle GNU/Linux's syscall SIGTRAPs. */
2348 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2350 /* No longer need the sysgood bit. The ptrace event ends up
2351 recorded in lp->waitstatus if we care for it. We can carry
2352 on handling the event like a regular SIGTRAP from here
2354 status = W_STOPCODE (SIGTRAP);
2355 if (linux_handle_syscall_trap (lp, 1))
2356 return wait_lwp (lp);
2359 /* Handle GNU/Linux's extended waitstatus for trace events. */
2360 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2362 if (debug_linux_nat)
2363 fprintf_unfiltered (gdb_stdlog,
2364 "WL: Handling extended status 0x%06x\n",
2366 if (linux_handle_extended_wait (lp, status, 1))
2367 return wait_lwp (lp);
2373 /* Send a SIGSTOP to LP. */
2376 stop_callback (struct lwp_info *lp, void *data)
2378 if (!lp->stopped && !lp->signalled)
2382 if (debug_linux_nat)
2384 fprintf_unfiltered (gdb_stdlog,
2385 "SC: kill %s **<SIGSTOP>**\n",
2386 target_pid_to_str (lp->ptid));
2389 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2390 if (debug_linux_nat)
2392 fprintf_unfiltered (gdb_stdlog,
2393 "SC: lwp kill %d %s\n",
2395 errno ? safe_strerror (errno) : "ERRNO-OK");
2399 gdb_assert (lp->status == 0);
2405 /* Request a stop on LWP. */
2408 linux_stop_lwp (struct lwp_info *lwp)
2410 stop_callback (lwp, NULL);
2413 /* Return non-zero if LWP PID has a pending SIGINT. */
2416 linux_nat_has_pending_sigint (int pid)
2418 sigset_t pending, blocked, ignored;
2420 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2422 if (sigismember (&pending, SIGINT)
2423 && !sigismember (&ignored, SIGINT))
2429 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2432 set_ignore_sigint (struct lwp_info *lp, void *data)
2434 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2435 flag to consume the next one. */
2436 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2437 && WSTOPSIG (lp->status) == SIGINT)
2440 lp->ignore_sigint = 1;
2445 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2446 This function is called after we know the LWP has stopped; if the LWP
2447 stopped before the expected SIGINT was delivered, then it will never have
2448 arrived. Also, if the signal was delivered to a shared queue and consumed
2449 by a different thread, it will never be delivered to this LWP. */
2452 maybe_clear_ignore_sigint (struct lwp_info *lp)
2454 if (!lp->ignore_sigint)
2457 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2459 if (debug_linux_nat)
2460 fprintf_unfiltered (gdb_stdlog,
2461 "MCIS: Clearing bogus flag for %s\n",
2462 target_pid_to_str (lp->ptid));
2463 lp->ignore_sigint = 0;
2467 /* Fetch the possible triggered data watchpoint info and store it in
2470 On some archs, like x86, that use debug registers to set
2471 watchpoints, it's possible that the way to know which watched
2472 address trapped, is to check the register that is used to select
2473 which address to watch. Problem is, between setting the watchpoint
2474 and reading back which data address trapped, the user may change
2475 the set of watchpoints, and, as a consequence, GDB changes the
2476 debug registers in the inferior. To avoid reading back a stale
2477 stopped-data-address when that happens, we cache in LP the fact
2478 that a watchpoint trapped, and the corresponding data address, as
2479 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2480 registers meanwhile, we have the cached data we can rely on. */
2483 save_sigtrap (struct lwp_info *lp)
2485 struct cleanup *old_chain;
2487 if (linux_ops->to_stopped_by_watchpoint == NULL)
2489 lp->stopped_by_watchpoint = 0;
2493 old_chain = save_inferior_ptid ();
2494 inferior_ptid = lp->ptid;
2496 lp->stopped_by_watchpoint = linux_ops->to_stopped_by_watchpoint (linux_ops);
2498 if (lp->stopped_by_watchpoint)
2500 if (linux_ops->to_stopped_data_address != NULL)
2501 lp->stopped_data_address_p =
2502 linux_ops->to_stopped_data_address (¤t_target,
2503 &lp->stopped_data_address);
2505 lp->stopped_data_address_p = 0;
2508 do_cleanups (old_chain);
2511 /* See save_sigtrap. */
2514 linux_nat_stopped_by_watchpoint (struct target_ops *ops)
2516 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2518 gdb_assert (lp != NULL);
2520 return lp->stopped_by_watchpoint;
2524 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2526 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2528 gdb_assert (lp != NULL);
2530 *addr_p = lp->stopped_data_address;
2532 return lp->stopped_data_address_p;
2535 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2538 sigtrap_is_event (int status)
2540 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2543 /* SIGTRAP-like events recognizer. */
2545 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
2547 /* Check for SIGTRAP-like events in LP. */
2550 linux_nat_lp_status_is_event (struct lwp_info *lp)
2552 /* We check for lp->waitstatus in addition to lp->status, because we can
2553 have pending process exits recorded in lp->status
2554 and W_EXITCODE(0,0) == 0. We should probably have an additional
2555 lp->status_p flag. */
2557 return (lp->waitstatus.kind == TARGET_WAITKIND_IGNORE
2558 && linux_nat_status_is_event (lp->status));
2561 /* Set alternative SIGTRAP-like events recognizer. If
2562 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2566 linux_nat_set_status_is_event (struct target_ops *t,
2567 int (*status_is_event) (int status))
2569 linux_nat_status_is_event = status_is_event;
2572 /* Wait until LP is stopped. */
2575 stop_wait_callback (struct lwp_info *lp, void *data)
2577 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2579 /* If this is a vfork parent, bail out, it is not going to report
2580 any SIGSTOP until the vfork is done with. */
2581 if (inf->vfork_child != NULL)
2588 status = wait_lwp (lp);
2592 if (lp->ignore_sigint && WIFSTOPPED (status)
2593 && WSTOPSIG (status) == SIGINT)
2595 lp->ignore_sigint = 0;
2598 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2600 if (debug_linux_nat)
2601 fprintf_unfiltered (gdb_stdlog,
2602 "PTRACE_CONT %s, 0, 0 (%s) "
2603 "(discarding SIGINT)\n",
2604 target_pid_to_str (lp->ptid),
2605 errno ? safe_strerror (errno) : "OK");
2607 return stop_wait_callback (lp, NULL);
2610 maybe_clear_ignore_sigint (lp);
2612 if (WSTOPSIG (status) != SIGSTOP)
2614 /* The thread was stopped with a signal other than SIGSTOP. */
2618 if (debug_linux_nat)
2619 fprintf_unfiltered (gdb_stdlog,
2620 "SWC: Pending event %s in %s\n",
2621 status_to_str ((int) status),
2622 target_pid_to_str (lp->ptid));
2624 /* Save the sigtrap event. */
2625 lp->status = status;
2626 gdb_assert (lp->signalled);
2630 /* We caught the SIGSTOP that we intended to catch, so
2631 there's no SIGSTOP pending. */
2633 if (debug_linux_nat)
2634 fprintf_unfiltered (gdb_stdlog,
2635 "SWC: Delayed SIGSTOP caught for %s.\n",
2636 target_pid_to_str (lp->ptid));
2638 /* Reset SIGNALLED only after the stop_wait_callback call
2639 above as it does gdb_assert on SIGNALLED. */
2647 /* Return non-zero if LP has a wait status pending. */
2650 status_callback (struct lwp_info *lp, void *data)
2652 /* Only report a pending wait status if we pretend that this has
2653 indeed been resumed. */
2657 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2659 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2660 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2661 0', so a clean process exit can not be stored pending in
2662 lp->status, it is indistinguishable from
2663 no-pending-status. */
2667 if (lp->status != 0)
2673 /* Return non-zero if LP isn't stopped. */
2676 running_callback (struct lwp_info *lp, void *data)
2678 return (!lp->stopped
2679 || ((lp->status != 0
2680 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2684 /* Count the LWP's that have had events. */
2687 count_events_callback (struct lwp_info *lp, void *data)
2691 gdb_assert (count != NULL);
2693 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2694 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2700 /* Select the LWP (if any) that is currently being single-stepped. */
2703 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2705 if (lp->last_resume_kind == resume_step
2712 /* Select the Nth LWP that has had a SIGTRAP event. */
2715 select_event_lwp_callback (struct lwp_info *lp, void *data)
2717 int *selector = data;
2719 gdb_assert (selector != NULL);
2721 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2722 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2723 if ((*selector)-- == 0)
2730 cancel_breakpoint (struct lwp_info *lp)
2732 /* Arrange for a breakpoint to be hit again later. We don't keep
2733 the SIGTRAP status and don't forward the SIGTRAP signal to the
2734 LWP. We will handle the current event, eventually we will resume
2735 this LWP, and this breakpoint will trap again.
2737 If we do not do this, then we run the risk that the user will
2738 delete or disable the breakpoint, but the LWP will have already
2741 struct regcache *regcache = get_thread_regcache (lp->ptid);
2742 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2745 pc = regcache_read_pc (regcache) - target_decr_pc_after_break (gdbarch);
2746 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2748 if (debug_linux_nat)
2749 fprintf_unfiltered (gdb_stdlog,
2750 "CB: Push back breakpoint for %s\n",
2751 target_pid_to_str (lp->ptid));
2753 /* Back up the PC if necessary. */
2754 if (target_decr_pc_after_break (gdbarch))
2755 regcache_write_pc (regcache, pc);
2763 cancel_breakpoints_callback (struct lwp_info *lp, void *data)
2765 struct lwp_info *event_lp = data;
2767 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2771 /* If a LWP other than the LWP that we're reporting an event for has
2772 hit a GDB breakpoint (as opposed to some random trap signal),
2773 then just arrange for it to hit it again later. We don't keep
2774 the SIGTRAP status and don't forward the SIGTRAP signal to the
2775 LWP. We will handle the current event, eventually we will resume
2776 all LWPs, and this one will get its breakpoint trap again.
2778 If we do not do this, then we run the risk that the user will
2779 delete or disable the breakpoint, but the LWP will have already
2782 if (linux_nat_lp_status_is_event (lp)
2783 && cancel_breakpoint (lp))
2784 /* Throw away the SIGTRAP. */
2790 /* Select one LWP out of those that have events pending. */
2793 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2796 int random_selector;
2797 struct lwp_info *event_lp;
2799 /* Record the wait status for the original LWP. */
2800 (*orig_lp)->status = *status;
2802 /* Give preference to any LWP that is being single-stepped. */
2803 event_lp = iterate_over_lwps (filter,
2804 select_singlestep_lwp_callback, NULL);
2805 if (event_lp != NULL)
2807 if (debug_linux_nat)
2808 fprintf_unfiltered (gdb_stdlog,
2809 "SEL: Select single-step %s\n",
2810 target_pid_to_str (event_lp->ptid));
2814 /* No single-stepping LWP. Select one at random, out of those
2815 which have had SIGTRAP events. */
2817 /* First see how many SIGTRAP events we have. */
2818 iterate_over_lwps (filter, count_events_callback, &num_events);
2820 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2821 random_selector = (int)
2822 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2824 if (debug_linux_nat && num_events > 1)
2825 fprintf_unfiltered (gdb_stdlog,
2826 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2827 num_events, random_selector);
2829 event_lp = iterate_over_lwps (filter,
2830 select_event_lwp_callback,
2834 if (event_lp != NULL)
2836 /* Switch the event LWP. */
2837 *orig_lp = event_lp;
2838 *status = event_lp->status;
2841 /* Flush the wait status for the event LWP. */
2842 (*orig_lp)->status = 0;
2845 /* Return non-zero if LP has been resumed. */
2848 resumed_callback (struct lwp_info *lp, void *data)
2853 /* Stop an active thread, verify it still exists, then resume it. If
2854 the thread ends up with a pending status, then it is not resumed,
2855 and *DATA (really a pointer to int), is set. */
2858 stop_and_resume_callback (struct lwp_info *lp, void *data)
2860 int *new_pending_p = data;
2864 ptid_t ptid = lp->ptid;
2866 stop_callback (lp, NULL);
2867 stop_wait_callback (lp, NULL);
2869 /* Resume if the lwp still exists, and the core wanted it
2871 lp = find_lwp_pid (ptid);
2874 if (lp->last_resume_kind == resume_stop
2877 /* The core wanted the LWP to stop. Even if it stopped
2878 cleanly (with SIGSTOP), leave the event pending. */
2879 if (debug_linux_nat)
2880 fprintf_unfiltered (gdb_stdlog,
2881 "SARC: core wanted LWP %ld stopped "
2882 "(leaving SIGSTOP pending)\n",
2883 ptid_get_lwp (lp->ptid));
2884 lp->status = W_STOPCODE (SIGSTOP);
2887 if (lp->status == 0)
2889 if (debug_linux_nat)
2890 fprintf_unfiltered (gdb_stdlog,
2891 "SARC: re-resuming LWP %ld\n",
2892 ptid_get_lwp (lp->ptid));
2893 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
2897 if (debug_linux_nat)
2898 fprintf_unfiltered (gdb_stdlog,
2899 "SARC: not re-resuming LWP %ld "
2901 ptid_get_lwp (lp->ptid));
2910 /* Check if we should go on and pass this event to common code.
2911 Return the affected lwp if we are, or NULL otherwise. If we stop
2912 all lwps temporarily, we may end up with new pending events in some
2913 other lwp. In that case set *NEW_PENDING_P to true. */
2915 static struct lwp_info *
2916 linux_nat_filter_event (int lwpid, int status, int *new_pending_p)
2918 struct lwp_info *lp;
2922 lp = find_lwp_pid (pid_to_ptid (lwpid));
2924 /* Check for stop events reported by a process we didn't already
2925 know about - anything not already in our LWP list.
2927 If we're expecting to receive stopped processes after
2928 fork, vfork, and clone events, then we'll just add the
2929 new one to our list and go back to waiting for the event
2930 to be reported - the stopped process might be returned
2931 from waitpid before or after the event is.
2933 But note the case of a non-leader thread exec'ing after the
2934 leader having exited, and gone from our lists. The non-leader
2935 thread changes its tid to the tgid. */
2937 if (WIFSTOPPED (status) && lp == NULL
2938 && (WSTOPSIG (status) == SIGTRAP && status >> 16 == PTRACE_EVENT_EXEC))
2940 /* A multi-thread exec after we had seen the leader exiting. */
2941 if (debug_linux_nat)
2942 fprintf_unfiltered (gdb_stdlog,
2943 "LLW: Re-adding thread group leader LWP %d.\n",
2946 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
2949 add_thread (lp->ptid);
2952 if (WIFSTOPPED (status) && !lp)
2954 add_to_pid_list (&stopped_pids, lwpid, status);
2958 /* Make sure we don't report an event for the exit of an LWP not in
2959 our list, i.e. not part of the current process. This can happen
2960 if we detach from a program we originally forked and then it
2962 if (!WIFSTOPPED (status) && !lp)
2965 /* This LWP is stopped now. (And if dead, this prevents it from
2966 ever being continued.) */
2969 /* Handle GNU/Linux's syscall SIGTRAPs. */
2970 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2972 /* No longer need the sysgood bit. The ptrace event ends up
2973 recorded in lp->waitstatus if we care for it. We can carry
2974 on handling the event like a regular SIGTRAP from here
2976 status = W_STOPCODE (SIGTRAP);
2977 if (linux_handle_syscall_trap (lp, 0))
2981 /* Handle GNU/Linux's extended waitstatus for trace events. */
2982 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2984 if (debug_linux_nat)
2985 fprintf_unfiltered (gdb_stdlog,
2986 "LLW: Handling extended status 0x%06x\n",
2988 if (linux_handle_extended_wait (lp, status, 0))
2992 if (linux_nat_status_is_event (status))
2995 /* Check if the thread has exited. */
2996 if ((WIFEXITED (status) || WIFSIGNALED (status))
2997 && num_lwps (ptid_get_pid (lp->ptid)) > 1)
2999 /* If this is the main thread, we must stop all threads and verify
3000 if they are still alive. This is because in the nptl thread model
3001 on Linux 2.4, there is no signal issued for exiting LWPs
3002 other than the main thread. We only get the main thread exit
3003 signal once all child threads have already exited. If we
3004 stop all the threads and use the stop_wait_callback to check
3005 if they have exited we can determine whether this signal
3006 should be ignored or whether it means the end of the debugged
3007 application, regardless of which threading model is being
3009 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
3011 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3012 stop_and_resume_callback, new_pending_p);
3015 if (debug_linux_nat)
3016 fprintf_unfiltered (gdb_stdlog,
3017 "LLW: %s exited.\n",
3018 target_pid_to_str (lp->ptid));
3020 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3022 /* If there is at least one more LWP, then the exit signal
3023 was not the end of the debugged application and should be
3030 /* Check if the current LWP has previously exited. In the nptl
3031 thread model, LWPs other than the main thread do not issue
3032 signals when they exit so we must check whenever the thread has
3033 stopped. A similar check is made in stop_wait_callback(). */
3034 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3036 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
3038 if (debug_linux_nat)
3039 fprintf_unfiltered (gdb_stdlog,
3040 "LLW: %s exited.\n",
3041 target_pid_to_str (lp->ptid));
3045 /* Make sure there is at least one thread running. */
3046 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3048 /* Discard the event. */
3052 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3053 an attempt to stop an LWP. */
3055 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3057 if (debug_linux_nat)
3058 fprintf_unfiltered (gdb_stdlog,
3059 "LLW: Delayed SIGSTOP caught for %s.\n",
3060 target_pid_to_str (lp->ptid));
3064 if (lp->last_resume_kind != resume_stop)
3066 /* This is a delayed SIGSTOP. */
3068 registers_changed ();
3070 if (linux_nat_prepare_to_resume != NULL)
3071 linux_nat_prepare_to_resume (lp);
3072 linux_ops->to_resume (linux_ops,
3073 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3074 lp->step, GDB_SIGNAL_0);
3075 if (debug_linux_nat)
3076 fprintf_unfiltered (gdb_stdlog,
3077 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3079 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3080 target_pid_to_str (lp->ptid));
3083 gdb_assert (lp->resumed);
3085 /* Discard the event. */
3090 /* Make sure we don't report a SIGINT that we have already displayed
3091 for another thread. */
3092 if (lp->ignore_sigint
3093 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3095 if (debug_linux_nat)
3096 fprintf_unfiltered (gdb_stdlog,
3097 "LLW: Delayed SIGINT caught for %s.\n",
3098 target_pid_to_str (lp->ptid));
3100 /* This is a delayed SIGINT. */
3101 lp->ignore_sigint = 0;
3103 registers_changed ();
3104 if (linux_nat_prepare_to_resume != NULL)
3105 linux_nat_prepare_to_resume (lp);
3106 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3107 lp->step, GDB_SIGNAL_0);
3108 if (debug_linux_nat)
3109 fprintf_unfiltered (gdb_stdlog,
3110 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3112 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3113 target_pid_to_str (lp->ptid));
3116 gdb_assert (lp->resumed);
3118 /* Discard the event. */
3122 /* An interesting event. */
3124 lp->status = status;
3128 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3129 their exits until all other threads in the group have exited. */
3132 check_zombie_leaders (void)
3134 struct inferior *inf;
3138 struct lwp_info *leader_lp;
3143 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3144 if (leader_lp != NULL
3145 /* Check if there are other threads in the group, as we may
3146 have raced with the inferior simply exiting. */
3147 && num_lwps (inf->pid) > 1
3148 && linux_proc_pid_is_zombie (inf->pid))
3150 if (debug_linux_nat)
3151 fprintf_unfiltered (gdb_stdlog,
3152 "CZL: Thread group leader %d zombie "
3153 "(it exited, or another thread execd).\n",
3156 /* A leader zombie can mean one of two things:
3158 - It exited, and there's an exit status pending
3159 available, or only the leader exited (not the whole
3160 program). In the latter case, we can't waitpid the
3161 leader's exit status until all other threads are gone.
3163 - There are 3 or more threads in the group, and a thread
3164 other than the leader exec'd. On an exec, the Linux
3165 kernel destroys all other threads (except the execing
3166 one) in the thread group, and resets the execing thread's
3167 tid to the tgid. No exit notification is sent for the
3168 execing thread -- from the ptracer's perspective, it
3169 appears as though the execing thread just vanishes.
3170 Until we reap all other threads except the leader and the
3171 execing thread, the leader will be zombie, and the
3172 execing thread will be in `D (disc sleep)'. As soon as
3173 all other threads are reaped, the execing thread changes
3174 it's tid to the tgid, and the previous (zombie) leader
3175 vanishes, giving place to the "new" leader. We could try
3176 distinguishing the exit and exec cases, by waiting once
3177 more, and seeing if something comes out, but it doesn't
3178 sound useful. The previous leader _does_ go away, and
3179 we'll re-add the new one once we see the exec event
3180 (which is just the same as what would happen if the
3181 previous leader did exit voluntarily before some other
3184 if (debug_linux_nat)
3185 fprintf_unfiltered (gdb_stdlog,
3186 "CZL: Thread group leader %d vanished.\n",
3188 exit_lwp (leader_lp);
3194 linux_nat_wait_1 (struct target_ops *ops,
3195 ptid_t ptid, struct target_waitstatus *ourstatus,
3198 static sigset_t prev_mask;
3199 enum resume_kind last_resume_kind;
3200 struct lwp_info *lp;
3203 if (debug_linux_nat)
3204 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3206 /* The first time we get here after starting a new inferior, we may
3207 not have added it to the LWP list yet - this is the earliest
3208 moment at which we know its PID. */
3209 if (ptid_is_pid (inferior_ptid))
3211 /* Upgrade the main thread's ptid. */
3212 thread_change_ptid (inferior_ptid,
3213 ptid_build (ptid_get_pid (inferior_ptid),
3214 ptid_get_pid (inferior_ptid), 0));
3216 lp = add_initial_lwp (inferior_ptid);
3220 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3221 block_child_signals (&prev_mask);
3227 /* First check if there is a LWP with a wait status pending. */
3228 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3230 /* Any LWP in the PTID group that's been resumed will do. */
3231 lp = iterate_over_lwps (ptid, status_callback, NULL);
3234 if (debug_linux_nat && lp->status)
3235 fprintf_unfiltered (gdb_stdlog,
3236 "LLW: Using pending wait status %s for %s.\n",
3237 status_to_str (lp->status),
3238 target_pid_to_str (lp->ptid));
3241 else if (ptid_lwp_p (ptid))
3243 if (debug_linux_nat)
3244 fprintf_unfiltered (gdb_stdlog,
3245 "LLW: Waiting for specific LWP %s.\n",
3246 target_pid_to_str (ptid));
3248 /* We have a specific LWP to check. */
3249 lp = find_lwp_pid (ptid);
3252 if (debug_linux_nat && lp->status)
3253 fprintf_unfiltered (gdb_stdlog,
3254 "LLW: Using pending wait status %s for %s.\n",
3255 status_to_str (lp->status),
3256 target_pid_to_str (lp->ptid));
3258 /* We check for lp->waitstatus in addition to lp->status,
3259 because we can have pending process exits recorded in
3260 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3261 an additional lp->status_p flag. */
3262 if (lp->status == 0 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3266 if (!target_can_async_p ())
3268 /* Causes SIGINT to be passed on to the attached process. */
3272 /* But if we don't find a pending event, we'll have to wait. */
3278 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3281 - If the thread group leader exits while other threads in the
3282 thread group still exist, waitpid(TGID, ...) hangs. That
3283 waitpid won't return an exit status until the other threads
3284 in the group are reapped.
3286 - When a non-leader thread execs, that thread just vanishes
3287 without reporting an exit (so we'd hang if we waited for it
3288 explicitly in that case). The exec event is reported to
3292 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3293 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3294 lwpid = my_waitpid (-1, &status, WNOHANG);
3296 if (debug_linux_nat)
3297 fprintf_unfiltered (gdb_stdlog,
3298 "LNW: waitpid(-1, ...) returned %d, %s\n",
3299 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3303 /* If this is true, then we paused LWPs momentarily, and may
3304 now have pending events to handle. */
3307 if (debug_linux_nat)
3309 fprintf_unfiltered (gdb_stdlog,
3310 "LLW: waitpid %ld received %s\n",
3311 (long) lwpid, status_to_str (status));
3314 lp = linux_nat_filter_event (lwpid, status, &new_pending);
3316 /* STATUS is now no longer valid, use LP->STATUS instead. */
3319 if (lp && !ptid_match (lp->ptid, ptid))
3321 gdb_assert (lp->resumed);
3323 if (debug_linux_nat)
3325 "LWP %ld got an event %06x, leaving pending.\n",
3326 ptid_get_lwp (lp->ptid), lp->status);
3328 if (WIFSTOPPED (lp->status))
3330 if (WSTOPSIG (lp->status) != SIGSTOP)
3332 /* Cancel breakpoint hits. The breakpoint may
3333 be removed before we fetch events from this
3334 process to report to the core. It is best
3335 not to assume the moribund breakpoints
3336 heuristic always handles these cases --- it
3337 could be too many events go through to the
3338 core before this one is handled. All-stop
3339 always cancels breakpoint hits in all
3342 && linux_nat_lp_status_is_event (lp)
3343 && cancel_breakpoint (lp))
3345 /* Throw away the SIGTRAP. */
3348 if (debug_linux_nat)
3350 "LLW: LWP %ld hit a breakpoint while"
3351 " waiting for another process;"
3353 ptid_get_lwp (lp->ptid));
3359 else if (WIFEXITED (lp->status) || WIFSIGNALED (lp->status))
3361 if (debug_linux_nat)
3363 "Process %ld exited while stopping LWPs\n",
3364 ptid_get_lwp (lp->ptid));
3366 /* This was the last lwp in the process. Since
3367 events are serialized to GDB core, and we can't
3368 report this one right now, but GDB core and the
3369 other target layers will want to be notified
3370 about the exit code/signal, leave the status
3371 pending for the next time we're able to report
3374 /* Dead LWP's aren't expected to reported a pending
3378 /* Store the pending event in the waitstatus as
3379 well, because W_EXITCODE(0,0) == 0. */
3380 store_waitstatus (&lp->waitstatus, lp->status);
3389 /* Some LWP now has a pending event. Go all the way
3390 back to check it. */
3396 /* We got an event to report to the core. */
3400 /* Retry until nothing comes out of waitpid. A single
3401 SIGCHLD can indicate more than one child stopped. */
3405 /* Check for zombie thread group leaders. Those can't be reaped
3406 until all other threads in the thread group are. */
3407 check_zombie_leaders ();
3409 /* If there are no resumed children left, bail. We'd be stuck
3410 forever in the sigsuspend call below otherwise. */
3411 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3413 if (debug_linux_nat)
3414 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3416 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3418 if (!target_can_async_p ())
3419 clear_sigint_trap ();
3421 restore_child_signals_mask (&prev_mask);
3422 return minus_one_ptid;
3425 /* No interesting event to report to the core. */
3427 if (target_options & TARGET_WNOHANG)
3429 if (debug_linux_nat)
3430 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3432 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3433 restore_child_signals_mask (&prev_mask);
3434 return minus_one_ptid;
3437 /* We shouldn't end up here unless we want to try again. */
3438 gdb_assert (lp == NULL);
3440 /* Block until we get an event reported with SIGCHLD. */
3441 sigsuspend (&suspend_mask);
3444 if (!target_can_async_p ())
3445 clear_sigint_trap ();
3449 status = lp->status;
3452 /* Don't report signals that GDB isn't interested in, such as
3453 signals that are neither printed nor stopped upon. Stopping all
3454 threads can be a bit time-consuming so if we want decent
3455 performance with heavily multi-threaded programs, especially when
3456 they're using a high frequency timer, we'd better avoid it if we
3459 if (WIFSTOPPED (status))
3461 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3463 /* When using hardware single-step, we need to report every signal.
3464 Otherwise, signals in pass_mask may be short-circuited. */
3466 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status)))
3468 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3469 here? It is not clear we should. GDB may not expect
3470 other threads to run. On the other hand, not resuming
3471 newly attached threads may cause an unwanted delay in
3472 getting them running. */
3473 registers_changed ();
3474 if (linux_nat_prepare_to_resume != NULL)
3475 linux_nat_prepare_to_resume (lp);
3476 linux_ops->to_resume (linux_ops,
3477 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3479 if (debug_linux_nat)
3480 fprintf_unfiltered (gdb_stdlog,
3481 "LLW: %s %s, %s (preempt 'handle')\n",
3483 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3484 target_pid_to_str (lp->ptid),
3485 (signo != GDB_SIGNAL_0
3486 ? strsignal (gdb_signal_to_host (signo))
3494 /* Only do the below in all-stop, as we currently use SIGINT
3495 to implement target_stop (see linux_nat_stop) in
3497 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3499 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3500 forwarded to the entire process group, that is, all LWPs
3501 will receive it - unless they're using CLONE_THREAD to
3502 share signals. Since we only want to report it once, we
3503 mark it as ignored for all LWPs except this one. */
3504 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid)),
3505 set_ignore_sigint, NULL);
3506 lp->ignore_sigint = 0;
3509 maybe_clear_ignore_sigint (lp);
3513 /* This LWP is stopped now. */
3516 if (debug_linux_nat)
3517 fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
3518 status_to_str (status), target_pid_to_str (lp->ptid));
3522 /* Now stop all other LWP's ... */
3523 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3525 /* ... and wait until all of them have reported back that
3526 they're no longer running. */
3527 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3529 /* If we're not waiting for a specific LWP, choose an event LWP
3530 from among those that have had events. Giving equal priority
3531 to all LWPs that have had events helps prevent
3533 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3534 select_event_lwp (ptid, &lp, &status);
3536 /* Now that we've selected our final event LWP, cancel any
3537 breakpoints in other LWPs that have hit a GDB breakpoint.
3538 See the comment in cancel_breakpoints_callback to find out
3540 iterate_over_lwps (minus_one_ptid, cancel_breakpoints_callback, lp);
3542 /* We'll need this to determine whether to report a SIGSTOP as
3543 TARGET_WAITKIND_0. Need to take a copy because
3544 resume_clear_callback clears it. */
3545 last_resume_kind = lp->last_resume_kind;
3547 /* In all-stop, from the core's perspective, all LWPs are now
3548 stopped until a new resume action is sent over. */
3549 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3554 last_resume_kind = lp->last_resume_kind;
3555 resume_clear_callback (lp, NULL);
3558 if (linux_nat_status_is_event (status))
3560 if (debug_linux_nat)
3561 fprintf_unfiltered (gdb_stdlog,
3562 "LLW: trap ptid is %s.\n",
3563 target_pid_to_str (lp->ptid));
3566 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3568 *ourstatus = lp->waitstatus;
3569 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3572 store_waitstatus (ourstatus, status);
3574 if (debug_linux_nat)
3575 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3577 restore_child_signals_mask (&prev_mask);
3579 if (last_resume_kind == resume_stop
3580 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3581 && WSTOPSIG (status) == SIGSTOP)
3583 /* A thread that has been requested to stop by GDB with
3584 target_stop, and it stopped cleanly, so report as SIG0. The
3585 use of SIGSTOP is an implementation detail. */
3586 ourstatus->value.sig = GDB_SIGNAL_0;
3589 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3590 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3593 lp->core = linux_common_core_of_thread (lp->ptid);
3598 /* Resume LWPs that are currently stopped without any pending status
3599 to report, but are resumed from the core's perspective. */
3602 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3604 ptid_t *wait_ptid_p = data;
3609 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3611 struct regcache *regcache = get_thread_regcache (lp->ptid);
3612 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3613 CORE_ADDR pc = regcache_read_pc (regcache);
3615 gdb_assert (is_executing (lp->ptid));
3617 /* Don't bother if there's a breakpoint at PC that we'd hit
3618 immediately, and we're not waiting for this LWP. */
3619 if (!ptid_match (lp->ptid, *wait_ptid_p))
3621 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3625 if (debug_linux_nat)
3626 fprintf_unfiltered (gdb_stdlog,
3627 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3628 target_pid_to_str (lp->ptid),
3629 paddress (gdbarch, pc),
3632 registers_changed ();
3633 if (linux_nat_prepare_to_resume != NULL)
3634 linux_nat_prepare_to_resume (lp);
3635 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3636 lp->step, GDB_SIGNAL_0);
3638 lp->stopped_by_watchpoint = 0;
3645 linux_nat_wait (struct target_ops *ops,
3646 ptid_t ptid, struct target_waitstatus *ourstatus,
3651 if (debug_linux_nat)
3653 char *options_string;
3655 options_string = target_options_to_string (target_options);
3656 fprintf_unfiltered (gdb_stdlog,
3657 "linux_nat_wait: [%s], [%s]\n",
3658 target_pid_to_str (ptid),
3660 xfree (options_string);
3663 /* Flush the async file first. */
3664 if (target_can_async_p ())
3665 async_file_flush ();
3667 /* Resume LWPs that are currently stopped without any pending status
3668 to report, but are resumed from the core's perspective. LWPs get
3669 in this state if we find them stopping at a time we're not
3670 interested in reporting the event (target_wait on a
3671 specific_process, for example, see linux_nat_wait_1), and
3672 meanwhile the event became uninteresting. Don't bother resuming
3673 LWPs we're not going to wait for if they'd stop immediately. */
3675 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3677 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3679 /* If we requested any event, and something came out, assume there
3680 may be more. If we requested a specific lwp or process, also
3681 assume there may be more. */
3682 if (target_can_async_p ()
3683 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3684 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3685 || !ptid_equal (ptid, minus_one_ptid)))
3688 /* Get ready for the next event. */
3689 if (target_can_async_p ())
3690 target_async (inferior_event_handler, 0);
3696 kill_callback (struct lwp_info *lp, void *data)
3698 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3701 kill (ptid_get_lwp (lp->ptid), SIGKILL);
3702 if (debug_linux_nat)
3703 fprintf_unfiltered (gdb_stdlog,
3704 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3705 target_pid_to_str (lp->ptid),
3706 errno ? safe_strerror (errno) : "OK");
3708 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3711 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3712 if (debug_linux_nat)
3713 fprintf_unfiltered (gdb_stdlog,
3714 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3715 target_pid_to_str (lp->ptid),
3716 errno ? safe_strerror (errno) : "OK");
3722 kill_wait_callback (struct lwp_info *lp, void *data)
3726 /* We must make sure that there are no pending events (delayed
3727 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3728 program doesn't interfere with any following debugging session. */
3730 /* For cloned processes we must check both with __WCLONE and
3731 without, since the exit status of a cloned process isn't reported
3737 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3738 if (pid != (pid_t) -1)
3740 if (debug_linux_nat)
3741 fprintf_unfiltered (gdb_stdlog,
3742 "KWC: wait %s received unknown.\n",
3743 target_pid_to_str (lp->ptid));
3744 /* The Linux kernel sometimes fails to kill a thread
3745 completely after PTRACE_KILL; that goes from the stop
3746 point in do_fork out to the one in
3747 get_signal_to_deliever and waits again. So kill it
3749 kill_callback (lp, NULL);
3752 while (pid == ptid_get_lwp (lp->ptid));
3754 gdb_assert (pid == -1 && errno == ECHILD);
3759 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3760 if (pid != (pid_t) -1)
3762 if (debug_linux_nat)
3763 fprintf_unfiltered (gdb_stdlog,
3764 "KWC: wait %s received unk.\n",
3765 target_pid_to_str (lp->ptid));
3766 /* See the call to kill_callback above. */
3767 kill_callback (lp, NULL);
3770 while (pid == ptid_get_lwp (lp->ptid));
3772 gdb_assert (pid == -1 && errno == ECHILD);
3777 linux_nat_kill (struct target_ops *ops)
3779 struct target_waitstatus last;
3783 /* If we're stopped while forking and we haven't followed yet,
3784 kill the other task. We need to do this first because the
3785 parent will be sleeping if this is a vfork. */
3787 get_last_target_status (&last_ptid, &last);
3789 if (last.kind == TARGET_WAITKIND_FORKED
3790 || last.kind == TARGET_WAITKIND_VFORKED)
3792 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3795 /* Let the arch-specific native code know this process is
3797 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3800 if (forks_exist_p ())
3801 linux_fork_killall ();
3804 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3806 /* Stop all threads before killing them, since ptrace requires
3807 that the thread is stopped to sucessfully PTRACE_KILL. */
3808 iterate_over_lwps (ptid, stop_callback, NULL);
3809 /* ... and wait until all of them have reported back that
3810 they're no longer running. */
3811 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3813 /* Kill all LWP's ... */
3814 iterate_over_lwps (ptid, kill_callback, NULL);
3816 /* ... and wait until we've flushed all events. */
3817 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3820 target_mourn_inferior ();
3824 linux_nat_mourn_inferior (struct target_ops *ops)
3826 int pid = ptid_get_pid (inferior_ptid);
3828 purge_lwp_list (pid);
3830 if (! forks_exist_p ())
3831 /* Normal case, no other forks available. */
3832 linux_ops->to_mourn_inferior (ops);
3834 /* Multi-fork case. The current inferior_ptid has exited, but
3835 there are other viable forks to debug. Delete the exiting
3836 one and context-switch to the first available. */
3837 linux_fork_mourn_inferior ();
3839 /* Let the arch-specific native code know this process is gone. */
3840 linux_nat_forget_process (pid);
3843 /* Convert a native/host siginfo object, into/from the siginfo in the
3844 layout of the inferiors' architecture. */
3847 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3851 if (linux_nat_siginfo_fixup != NULL)
3852 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3854 /* If there was no callback, or the callback didn't do anything,
3855 then just do a straight memcpy. */
3859 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3861 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3865 static enum target_xfer_status
3866 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3867 const char *annex, gdb_byte *readbuf,
3868 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3869 ULONGEST *xfered_len)
3873 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3875 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3876 gdb_assert (readbuf || writebuf);
3878 pid = ptid_get_lwp (inferior_ptid);
3880 pid = ptid_get_pid (inferior_ptid);
3882 if (offset > sizeof (siginfo))
3883 return TARGET_XFER_E_IO;
3886 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3888 return TARGET_XFER_E_IO;
3890 /* When GDB is built as a 64-bit application, ptrace writes into
3891 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3892 inferior with a 64-bit GDB should look the same as debugging it
3893 with a 32-bit GDB, we need to convert it. GDB core always sees
3894 the converted layout, so any read/write will have to be done
3896 siginfo_fixup (&siginfo, inf_siginfo, 0);
3898 if (offset + len > sizeof (siginfo))
3899 len = sizeof (siginfo) - offset;
3901 if (readbuf != NULL)
3902 memcpy (readbuf, inf_siginfo + offset, len);
3905 memcpy (inf_siginfo + offset, writebuf, len);
3907 /* Convert back to ptrace layout before flushing it out. */
3908 siginfo_fixup (&siginfo, inf_siginfo, 1);
3911 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3913 return TARGET_XFER_E_IO;
3917 return TARGET_XFER_OK;
3920 static enum target_xfer_status
3921 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3922 const char *annex, gdb_byte *readbuf,
3923 const gdb_byte *writebuf,
3924 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3926 struct cleanup *old_chain;
3927 enum target_xfer_status xfer;
3929 if (object == TARGET_OBJECT_SIGNAL_INFO)
3930 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3931 offset, len, xfered_len);
3933 /* The target is connected but no live inferior is selected. Pass
3934 this request down to a lower stratum (e.g., the executable
3936 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3937 return TARGET_XFER_EOF;
3939 old_chain = save_inferior_ptid ();
3941 if (ptid_lwp_p (inferior_ptid))
3942 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3944 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3945 offset, len, xfered_len);
3947 do_cleanups (old_chain);
3952 linux_thread_alive (ptid_t ptid)
3956 gdb_assert (ptid_lwp_p (ptid));
3958 /* Send signal 0 instead of anything ptrace, because ptracing a
3959 running thread errors out claiming that the thread doesn't
3961 err = kill_lwp (ptid_get_lwp (ptid), 0);
3963 if (debug_linux_nat)
3964 fprintf_unfiltered (gdb_stdlog,
3965 "LLTA: KILL(SIG0) %s (%s)\n",
3966 target_pid_to_str (ptid),
3967 err ? safe_strerror (tmp_errno) : "OK");
3976 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3978 return linux_thread_alive (ptid);
3982 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3984 static char buf[64];
3986 if (ptid_lwp_p (ptid)
3987 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
3988 || num_lwps (ptid_get_pid (ptid)) > 1))
3990 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
3994 return normal_pid_to_str (ptid);
3998 linux_nat_thread_name (struct target_ops *self, struct thread_info *thr)
4000 int pid = ptid_get_pid (thr->ptid);
4001 long lwp = ptid_get_lwp (thr->ptid);
4002 #define FORMAT "/proc/%d/task/%ld/comm"
4003 char buf[sizeof (FORMAT) + 30];
4005 char *result = NULL;
4007 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
4008 comm_file = gdb_fopen_cloexec (buf, "r");
4011 /* Not exported by the kernel, so we define it here. */
4013 static char line[COMM_LEN + 1];
4015 if (fgets (line, sizeof (line), comm_file))
4017 char *nl = strchr (line, '\n');
4034 /* Accepts an integer PID; Returns a string representing a file that
4035 can be opened to get the symbols for the child process. */
4038 linux_child_pid_to_exec_file (struct target_ops *self, int pid)
4040 static char buf[PATH_MAX];
4041 char name[PATH_MAX];
4043 xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
4044 memset (buf, 0, PATH_MAX);
4045 if (readlink (name, buf, PATH_MAX - 1) <= 0)
4051 /* Records the thread's register state for the corefile note
4055 linux_nat_collect_thread_registers (const struct regcache *regcache,
4056 ptid_t ptid, bfd *obfd,
4057 char *note_data, int *note_size,
4058 enum gdb_signal stop_signal)
4060 struct gdbarch *gdbarch = get_regcache_arch (regcache);
4061 const struct regset *regset;
4063 gdb_gregset_t gregs;
4064 gdb_fpregset_t fpregs;
4066 core_regset_p = gdbarch_regset_from_core_section_p (gdbarch);
4069 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg",
4071 != NULL && regset->collect_regset != NULL)
4072 regset->collect_regset (regset, regcache, -1, &gregs, sizeof (gregs));
4074 fill_gregset (regcache, &gregs, -1);
4076 note_data = (char *) elfcore_write_prstatus
4077 (obfd, note_data, note_size, ptid_get_lwp (ptid),
4078 gdb_signal_to_host (stop_signal), &gregs);
4081 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
4083 != NULL && regset->collect_regset != NULL)
4084 regset->collect_regset (regset, regcache, -1, &fpregs, sizeof (fpregs));
4086 fill_fpregset (regcache, &fpregs, -1);
4088 note_data = (char *) elfcore_write_prfpreg (obfd, note_data, note_size,
4089 &fpregs, sizeof (fpregs));
4094 /* Fills the "to_make_corefile_note" target vector. Builds the note
4095 section for a corefile, and returns it in a malloc buffer. */
4098 linux_nat_make_corefile_notes (struct target_ops *self,
4099 bfd *obfd, int *note_size)
4101 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4102 converted to gdbarch_core_regset_sections, this function can go away. */
4103 return linux_make_corefile_notes (target_gdbarch (), obfd, note_size,
4104 linux_nat_collect_thread_registers);
4107 /* Implement the to_xfer_partial interface for memory reads using the /proc
4108 filesystem. Because we can use a single read() call for /proc, this
4109 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4110 but it doesn't support writes. */
4112 static enum target_xfer_status
4113 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
4114 const char *annex, gdb_byte *readbuf,
4115 const gdb_byte *writebuf,
4116 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
4122 if (object != TARGET_OBJECT_MEMORY || !readbuf)
4125 /* Don't bother for one word. */
4126 if (len < 3 * sizeof (long))
4127 return TARGET_XFER_EOF;
4129 /* We could keep this file open and cache it - possibly one per
4130 thread. That requires some juggling, but is even faster. */
4131 xsnprintf (filename, sizeof filename, "/proc/%d/mem",
4132 ptid_get_pid (inferior_ptid));
4133 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
4135 return TARGET_XFER_EOF;
4137 /* If pread64 is available, use it. It's faster if the kernel
4138 supports it (only one syscall), and it's 64-bit safe even on
4139 32-bit platforms (for instance, SPARC debugging a SPARC64
4142 if (pread64 (fd, readbuf, len, offset) != len)
4144 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
4153 return TARGET_XFER_EOF;
4157 return TARGET_XFER_OK;
4162 /* Enumerate spufs IDs for process PID. */
4164 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
4166 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4168 LONGEST written = 0;
4171 struct dirent *entry;
4173 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4174 dir = opendir (path);
4179 while ((entry = readdir (dir)) != NULL)
4185 fd = atoi (entry->d_name);
4189 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4190 if (stat (path, &st) != 0)
4192 if (!S_ISDIR (st.st_mode))
4195 if (statfs (path, &stfs) != 0)
4197 if (stfs.f_type != SPUFS_MAGIC)
4200 if (pos >= offset && pos + 4 <= offset + len)
4202 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4212 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4213 object type, using the /proc file system. */
4215 static enum target_xfer_status
4216 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
4217 const char *annex, gdb_byte *readbuf,
4218 const gdb_byte *writebuf,
4219 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
4224 int pid = ptid_get_pid (inferior_ptid);
4229 return TARGET_XFER_E_IO;
4232 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
4235 return TARGET_XFER_E_IO;
4237 return TARGET_XFER_EOF;
4240 *xfered_len = (ULONGEST) l;
4241 return TARGET_XFER_OK;
4246 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4247 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4249 return TARGET_XFER_E_IO;
4252 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4255 return TARGET_XFER_EOF;
4259 ret = write (fd, writebuf, (size_t) len);
4261 ret = read (fd, readbuf, (size_t) len);
4266 return TARGET_XFER_E_IO;
4268 return TARGET_XFER_EOF;
4271 *xfered_len = (ULONGEST) ret;
4272 return TARGET_XFER_OK;
4277 /* Parse LINE as a signal set and add its set bits to SIGS. */
4280 add_line_to_sigset (const char *line, sigset_t *sigs)
4282 int len = strlen (line) - 1;
4286 if (line[len] != '\n')
4287 error (_("Could not parse signal set: %s"), line);
4295 if (*p >= '0' && *p <= '9')
4297 else if (*p >= 'a' && *p <= 'f')
4298 digit = *p - 'a' + 10;
4300 error (_("Could not parse signal set: %s"), line);
4305 sigaddset (sigs, signum + 1);
4307 sigaddset (sigs, signum + 2);
4309 sigaddset (sigs, signum + 3);
4311 sigaddset (sigs, signum + 4);
4317 /* Find process PID's pending signals from /proc/pid/status and set
4321 linux_proc_pending_signals (int pid, sigset_t *pending,
4322 sigset_t *blocked, sigset_t *ignored)
4325 char buffer[PATH_MAX], fname[PATH_MAX];
4326 struct cleanup *cleanup;
4328 sigemptyset (pending);
4329 sigemptyset (blocked);
4330 sigemptyset (ignored);
4331 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4332 procfile = gdb_fopen_cloexec (fname, "r");
4333 if (procfile == NULL)
4334 error (_("Could not open %s"), fname);
4335 cleanup = make_cleanup_fclose (procfile);
4337 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4339 /* Normal queued signals are on the SigPnd line in the status
4340 file. However, 2.6 kernels also have a "shared" pending
4341 queue for delivering signals to a thread group, so check for
4344 Unfortunately some Red Hat kernels include the shared pending
4345 queue but not the ShdPnd status field. */
4347 if (strncmp (buffer, "SigPnd:\t", 8) == 0)
4348 add_line_to_sigset (buffer + 8, pending);
4349 else if (strncmp (buffer, "ShdPnd:\t", 8) == 0)
4350 add_line_to_sigset (buffer + 8, pending);
4351 else if (strncmp (buffer, "SigBlk:\t", 8) == 0)
4352 add_line_to_sigset (buffer + 8, blocked);
4353 else if (strncmp (buffer, "SigIgn:\t", 8) == 0)
4354 add_line_to_sigset (buffer + 8, ignored);
4357 do_cleanups (cleanup);
4360 static enum target_xfer_status
4361 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4362 const char *annex, gdb_byte *readbuf,
4363 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4364 ULONGEST *xfered_len)
4366 gdb_assert (object == TARGET_OBJECT_OSDATA);
4368 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4369 if (*xfered_len == 0)
4370 return TARGET_XFER_EOF;
4372 return TARGET_XFER_OK;
4375 static enum target_xfer_status
4376 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4377 const char *annex, gdb_byte *readbuf,
4378 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4379 ULONGEST *xfered_len)
4381 enum target_xfer_status xfer;
4383 if (object == TARGET_OBJECT_AUXV)
4384 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4385 offset, len, xfered_len);
4387 if (object == TARGET_OBJECT_OSDATA)
4388 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4389 offset, len, xfered_len);
4391 if (object == TARGET_OBJECT_SPU)
4392 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4393 offset, len, xfered_len);
4395 /* GDB calculates all the addresses in possibly larget width of the address.
4396 Address width needs to be masked before its final use - either by
4397 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4399 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4401 if (object == TARGET_OBJECT_MEMORY)
4403 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4405 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4406 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4409 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4410 offset, len, xfered_len);
4411 if (xfer != TARGET_XFER_EOF)
4414 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4415 offset, len, xfered_len);
4419 cleanup_target_stop (void *arg)
4421 ptid_t *ptid = (ptid_t *) arg;
4423 gdb_assert (arg != NULL);
4426 target_resume (*ptid, 0, GDB_SIGNAL_0);
4429 static VEC(static_tracepoint_marker_p) *
4430 linux_child_static_tracepoint_markers_by_strid (struct target_ops *self,
4433 char s[IPA_CMD_BUF_SIZE];
4434 struct cleanup *old_chain;
4435 int pid = ptid_get_pid (inferior_ptid);
4436 VEC(static_tracepoint_marker_p) *markers = NULL;
4437 struct static_tracepoint_marker *marker = NULL;
4439 ptid_t ptid = ptid_build (pid, 0, 0);
4444 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4445 s[sizeof ("qTfSTM")] = 0;
4447 agent_run_command (pid, s, strlen (s) + 1);
4449 old_chain = make_cleanup (free_current_marker, &marker);
4450 make_cleanup (cleanup_target_stop, &ptid);
4455 marker = XCNEW (struct static_tracepoint_marker);
4459 parse_static_tracepoint_marker_definition (p, &p, marker);
4461 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4463 VEC_safe_push (static_tracepoint_marker_p,
4469 release_static_tracepoint_marker (marker);
4470 memset (marker, 0, sizeof (*marker));
4473 while (*p++ == ','); /* comma-separated list */
4475 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4476 s[sizeof ("qTsSTM")] = 0;
4477 agent_run_command (pid, s, strlen (s) + 1);
4481 do_cleanups (old_chain);
4486 /* Create a prototype generic GNU/Linux target. The client can override
4487 it with local methods. */
4490 linux_target_install_ops (struct target_ops *t)
4492 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4493 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4494 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4495 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4496 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4497 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4498 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4499 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4500 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4501 t->to_post_attach = linux_child_post_attach;
4502 t->to_follow_fork = linux_child_follow_fork;
4503 t->to_make_corefile_notes = linux_nat_make_corefile_notes;
4505 super_xfer_partial = t->to_xfer_partial;
4506 t->to_xfer_partial = linux_xfer_partial;
4508 t->to_static_tracepoint_markers_by_strid
4509 = linux_child_static_tracepoint_markers_by_strid;
4515 struct target_ops *t;
4517 t = inf_ptrace_target ();
4518 linux_target_install_ops (t);
4524 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4526 struct target_ops *t;
4528 t = inf_ptrace_trad_target (register_u_offset);
4529 linux_target_install_ops (t);
4534 /* target_is_async_p implementation. */
4537 linux_nat_is_async_p (struct target_ops *ops)
4539 /* NOTE: palves 2008-03-21: We're only async when the user requests
4540 it explicitly with the "set target-async" command.
4541 Someday, linux will always be async. */
4542 return target_async_permitted;
4545 /* target_can_async_p implementation. */
4548 linux_nat_can_async_p (struct target_ops *ops)
4550 /* NOTE: palves 2008-03-21: We're only async when the user requests
4551 it explicitly with the "set target-async" command.
4552 Someday, linux will always be async. */
4553 return target_async_permitted;
4557 linux_nat_supports_non_stop (struct target_ops *self)
4562 /* True if we want to support multi-process. To be removed when GDB
4563 supports multi-exec. */
4565 int linux_multi_process = 1;
4568 linux_nat_supports_multi_process (struct target_ops *self)
4570 return linux_multi_process;
4574 linux_nat_supports_disable_randomization (struct target_ops *self)
4576 #ifdef HAVE_PERSONALITY
4583 static int async_terminal_is_ours = 1;
4585 /* target_terminal_inferior implementation. */
4588 linux_nat_terminal_inferior (struct target_ops *self)
4590 if (!target_is_async_p ())
4592 /* Async mode is disabled. */
4593 child_terminal_inferior (self);
4597 child_terminal_inferior (self);
4599 /* Calls to target_terminal_*() are meant to be idempotent. */
4600 if (!async_terminal_is_ours)
4603 delete_file_handler (input_fd);
4604 async_terminal_is_ours = 0;
4608 /* target_terminal_ours implementation. */
4611 linux_nat_terminal_ours (struct target_ops *self)
4613 if (!target_is_async_p ())
4615 /* Async mode is disabled. */
4616 child_terminal_ours (self);
4620 /* GDB should never give the terminal to the inferior if the
4621 inferior is running in the background (run&, continue&, etc.),
4622 but claiming it sure should. */
4623 child_terminal_ours (self);
4625 if (async_terminal_is_ours)
4628 clear_sigint_trap ();
4629 add_file_handler (input_fd, stdin_event_handler, 0);
4630 async_terminal_is_ours = 1;
4633 static void (*async_client_callback) (enum inferior_event_type event_type,
4635 static void *async_client_context;
4637 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4638 so we notice when any child changes state, and notify the
4639 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4640 above to wait for the arrival of a SIGCHLD. */
4643 sigchld_handler (int signo)
4645 int old_errno = errno;
4647 if (debug_linux_nat)
4648 ui_file_write_async_safe (gdb_stdlog,
4649 "sigchld\n", sizeof ("sigchld\n") - 1);
4651 if (signo == SIGCHLD
4652 && linux_nat_event_pipe[0] != -1)
4653 async_file_mark (); /* Let the event loop know that there are
4654 events to handle. */
4659 /* Callback registered with the target events file descriptor. */
4662 handle_target_event (int error, gdb_client_data client_data)
4664 (*async_client_callback) (INF_REG_EVENT, async_client_context);
4667 /* Create/destroy the target events pipe. Returns previous state. */
4670 linux_async_pipe (int enable)
4672 int previous = (linux_nat_event_pipe[0] != -1);
4674 if (previous != enable)
4678 /* Block child signals while we create/destroy the pipe, as
4679 their handler writes to it. */
4680 block_child_signals (&prev_mask);
4684 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4685 internal_error (__FILE__, __LINE__,
4686 "creating event pipe failed.");
4688 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4689 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4693 close (linux_nat_event_pipe[0]);
4694 close (linux_nat_event_pipe[1]);
4695 linux_nat_event_pipe[0] = -1;
4696 linux_nat_event_pipe[1] = -1;
4699 restore_child_signals_mask (&prev_mask);
4705 /* target_async implementation. */
4708 linux_nat_async (struct target_ops *ops,
4709 void (*callback) (enum inferior_event_type event_type,
4713 if (callback != NULL)
4715 async_client_callback = callback;
4716 async_client_context = context;
4717 if (!linux_async_pipe (1))
4719 add_file_handler (linux_nat_event_pipe[0],
4720 handle_target_event, NULL);
4721 /* There may be pending events to handle. Tell the event loop
4728 async_client_callback = callback;
4729 async_client_context = context;
4730 delete_file_handler (linux_nat_event_pipe[0]);
4731 linux_async_pipe (0);
4736 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4740 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4744 if (debug_linux_nat)
4745 fprintf_unfiltered (gdb_stdlog,
4746 "LNSL: running -> suspending %s\n",
4747 target_pid_to_str (lwp->ptid));
4750 if (lwp->last_resume_kind == resume_stop)
4752 if (debug_linux_nat)
4753 fprintf_unfiltered (gdb_stdlog,
4754 "linux-nat: already stopping LWP %ld at "
4756 ptid_get_lwp (lwp->ptid));
4760 stop_callback (lwp, NULL);
4761 lwp->last_resume_kind = resume_stop;
4765 /* Already known to be stopped; do nothing. */
4767 if (debug_linux_nat)
4769 if (find_thread_ptid (lwp->ptid)->stop_requested)
4770 fprintf_unfiltered (gdb_stdlog,
4771 "LNSL: already stopped/stop_requested %s\n",
4772 target_pid_to_str (lwp->ptid));
4774 fprintf_unfiltered (gdb_stdlog,
4775 "LNSL: already stopped/no "
4776 "stop_requested yet %s\n",
4777 target_pid_to_str (lwp->ptid));
4784 linux_nat_stop (struct target_ops *self, ptid_t ptid)
4787 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4789 linux_ops->to_stop (linux_ops, ptid);
4793 linux_nat_close (struct target_ops *self)
4795 /* Unregister from the event loop. */
4796 if (linux_nat_is_async_p (NULL))
4797 linux_nat_async (NULL, NULL, 0);
4799 if (linux_ops->to_close)
4800 linux_ops->to_close (linux_ops);
4805 /* When requests are passed down from the linux-nat layer to the
4806 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4807 used. The address space pointer is stored in the inferior object,
4808 but the common code that is passed such ptid can't tell whether
4809 lwpid is a "main" process id or not (it assumes so). We reverse
4810 look up the "main" process id from the lwp here. */
4812 static struct address_space *
4813 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4815 struct lwp_info *lwp;
4816 struct inferior *inf;
4819 pid = ptid_get_lwp (ptid);
4820 if (ptid_get_lwp (ptid) == 0)
4822 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4824 lwp = find_lwp_pid (ptid);
4825 pid = ptid_get_pid (lwp->ptid);
4829 /* A (pid,lwpid,0) ptid. */
4830 pid = ptid_get_pid (ptid);
4833 inf = find_inferior_pid (pid);
4834 gdb_assert (inf != NULL);
4838 /* Return the cached value of the processor core for thread PTID. */
4841 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4843 struct lwp_info *info = find_lwp_pid (ptid);
4851 linux_nat_add_target (struct target_ops *t)
4853 /* Save the provided single-threaded target. We save this in a separate
4854 variable because another target we've inherited from (e.g. inf-ptrace)
4855 may have saved a pointer to T; we want to use it for the final
4856 process stratum target. */
4857 linux_ops_saved = *t;
4858 linux_ops = &linux_ops_saved;
4860 /* Override some methods for multithreading. */
4861 t->to_create_inferior = linux_nat_create_inferior;
4862 t->to_attach = linux_nat_attach;
4863 t->to_detach = linux_nat_detach;
4864 t->to_resume = linux_nat_resume;
4865 t->to_wait = linux_nat_wait;
4866 t->to_pass_signals = linux_nat_pass_signals;
4867 t->to_xfer_partial = linux_nat_xfer_partial;
4868 t->to_kill = linux_nat_kill;
4869 t->to_mourn_inferior = linux_nat_mourn_inferior;
4870 t->to_thread_alive = linux_nat_thread_alive;
4871 t->to_pid_to_str = linux_nat_pid_to_str;
4872 t->to_thread_name = linux_nat_thread_name;
4873 t->to_has_thread_control = tc_schedlock;
4874 t->to_thread_address_space = linux_nat_thread_address_space;
4875 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4876 t->to_stopped_data_address = linux_nat_stopped_data_address;
4878 t->to_can_async_p = linux_nat_can_async_p;
4879 t->to_is_async_p = linux_nat_is_async_p;
4880 t->to_supports_non_stop = linux_nat_supports_non_stop;
4881 t->to_async = linux_nat_async;
4882 t->to_terminal_inferior = linux_nat_terminal_inferior;
4883 t->to_terminal_ours = linux_nat_terminal_ours;
4885 super_close = t->to_close;
4886 t->to_close = linux_nat_close;
4888 /* Methods for non-stop support. */
4889 t->to_stop = linux_nat_stop;
4891 t->to_supports_multi_process = linux_nat_supports_multi_process;
4893 t->to_supports_disable_randomization
4894 = linux_nat_supports_disable_randomization;
4896 t->to_core_of_thread = linux_nat_core_of_thread;
4898 /* We don't change the stratum; this target will sit at
4899 process_stratum and thread_db will set at thread_stratum. This
4900 is a little strange, since this is a multi-threaded-capable
4901 target, but we want to be on the stack below thread_db, and we
4902 also want to be used for single-threaded processes. */
4907 /* Register a method to call whenever a new thread is attached. */
4909 linux_nat_set_new_thread (struct target_ops *t,
4910 void (*new_thread) (struct lwp_info *))
4912 /* Save the pointer. We only support a single registered instance
4913 of the GNU/Linux native target, so we do not need to map this to
4915 linux_nat_new_thread = new_thread;
4918 /* See declaration in linux-nat.h. */
4921 linux_nat_set_new_fork (struct target_ops *t,
4922 linux_nat_new_fork_ftype *new_fork)
4924 /* Save the pointer. */
4925 linux_nat_new_fork = new_fork;
4928 /* See declaration in linux-nat.h. */
4931 linux_nat_set_forget_process (struct target_ops *t,
4932 linux_nat_forget_process_ftype *fn)
4934 /* Save the pointer. */
4935 linux_nat_forget_process_hook = fn;
4938 /* See declaration in linux-nat.h. */
4941 linux_nat_forget_process (pid_t pid)
4943 if (linux_nat_forget_process_hook != NULL)
4944 linux_nat_forget_process_hook (pid);
4947 /* Register a method that converts a siginfo object between the layout
4948 that ptrace returns, and the layout in the architecture of the
4951 linux_nat_set_siginfo_fixup (struct target_ops *t,
4952 int (*siginfo_fixup) (siginfo_t *,
4956 /* Save the pointer. */
4957 linux_nat_siginfo_fixup = siginfo_fixup;
4960 /* Register a method to call prior to resuming a thread. */
4963 linux_nat_set_prepare_to_resume (struct target_ops *t,
4964 void (*prepare_to_resume) (struct lwp_info *))
4966 /* Save the pointer. */
4967 linux_nat_prepare_to_resume = prepare_to_resume;
4970 /* See linux-nat.h. */
4973 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
4977 pid = ptid_get_lwp (ptid);
4979 pid = ptid_get_pid (ptid);
4982 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
4985 memset (siginfo, 0, sizeof (*siginfo));
4991 /* Provide a prototype to silence -Wmissing-prototypes. */
4992 extern initialize_file_ftype _initialize_linux_nat;
4995 _initialize_linux_nat (void)
4997 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
4998 &debug_linux_nat, _("\
4999 Set debugging of GNU/Linux lwp module."), _("\
5000 Show debugging of GNU/Linux lwp module."), _("\
5001 Enables printf debugging output."),
5003 show_debug_linux_nat,
5004 &setdebuglist, &showdebuglist);
5006 /* Save this mask as the default. */
5007 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
5009 /* Install a SIGCHLD handler. */
5010 sigchld_action.sa_handler = sigchld_handler;
5011 sigemptyset (&sigchld_action.sa_mask);
5012 sigchld_action.sa_flags = SA_RESTART;
5014 /* Make it the default. */
5015 sigaction (SIGCHLD, &sigchld_action, NULL);
5017 /* Make sure we don't block SIGCHLD during a sigsuspend. */
5018 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
5019 sigdelset (&suspend_mask, SIGCHLD);
5021 sigemptyset (&blocked_mask);
5025 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
5026 the GNU/Linux Threads library and therefore doesn't really belong
5029 /* Read variable NAME in the target and return its value if found.
5030 Otherwise return zero. It is assumed that the type of the variable
5034 get_signo (const char *name)
5036 struct bound_minimal_symbol ms;
5039 ms = lookup_minimal_symbol (name, NULL, NULL);
5040 if (ms.minsym == NULL)
5043 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
5044 sizeof (signo)) != 0)
5050 /* Return the set of signals used by the threads library in *SET. */
5053 lin_thread_get_thread_signals (sigset_t *set)
5055 struct sigaction action;
5056 int restart, cancel;
5058 sigemptyset (&blocked_mask);
5061 restart = get_signo ("__pthread_sig_restart");
5062 cancel = get_signo ("__pthread_sig_cancel");
5064 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5065 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5066 not provide any way for the debugger to query the signal numbers -
5067 fortunately they don't change! */
5070 restart = __SIGRTMIN;
5073 cancel = __SIGRTMIN + 1;
5075 sigaddset (set, restart);
5076 sigaddset (set, cancel);
5078 /* The GNU/Linux Threads library makes terminating threads send a
5079 special "cancel" signal instead of SIGCHLD. Make sure we catch
5080 those (to prevent them from terminating GDB itself, which is
5081 likely to be their default action) and treat them the same way as
5084 action.sa_handler = sigchld_handler;
5085 sigemptyset (&action.sa_mask);
5086 action.sa_flags = SA_RESTART;
5087 sigaction (cancel, &action, NULL);
5089 /* We block the "cancel" signal throughout this code ... */
5090 sigaddset (&blocked_mask, cancel);
5091 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
5093 /* ... except during a sigsuspend. */
5094 sigdelset (&suspend_mask, cancel);