1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2012 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "gdb_string.h"
25 #include "gdb_assert.h"
26 #ifdef HAVE_TKILL_SYSCALL
28 #include <sys/syscall.h>
30 #include <sys/ptrace.h>
31 #include "linux-nat.h"
32 #include "linux-ptrace.h"
33 #include "linux-procfs.h"
34 #include "linux-fork.h"
35 #include "gdbthread.h"
39 #include "inf-ptrace.h"
41 #include <sys/param.h> /* for MAXPATHLEN */
42 #include <sys/procfs.h> /* for elf_gregset etc. */
43 #include "elf-bfd.h" /* for elfcore_write_* */
44 #include "gregset.h" /* for gregset */
45 #include "gdbcore.h" /* for get_exec_file */
46 #include <ctype.h> /* for isdigit */
47 #include "gdbthread.h" /* for struct thread_info etc. */
48 #include "gdb_stat.h" /* for struct stat */
49 #include <fcntl.h> /* for O_RDONLY */
51 #include "event-loop.h"
52 #include "event-top.h"
54 #include <sys/types.h>
55 #include "gdb_dirent.h"
56 #include "xml-support.h"
60 #include "linux-osdata.h"
61 #include "linux-tdep.h"
64 #include "tracepoint.h"
65 #include "exceptions.h"
66 #include "linux-ptrace.h"
70 #define SPUFS_MAGIC 0x23c9b64e
73 #ifdef HAVE_PERSONALITY
74 # include <sys/personality.h>
75 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
76 # define ADDR_NO_RANDOMIZE 0x0040000
78 #endif /* HAVE_PERSONALITY */
80 /* This comment documents high-level logic of this file.
82 Waiting for events in sync mode
83 ===============================
85 When waiting for an event in a specific thread, we just use waitpid, passing
86 the specific pid, and not passing WNOHANG.
88 When waiting for an event in all threads, waitpid is not quite good. Prior to
89 version 2.4, Linux can either wait for event in main thread, or in secondary
90 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
91 miss an event. The solution is to use non-blocking waitpid, together with
92 sigsuspend. First, we use non-blocking waitpid to get an event in the main
93 process, if any. Second, we use non-blocking waitpid with the __WCLONED
94 flag to check for events in cloned processes. If nothing is found, we use
95 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
96 happened to a child process -- and SIGCHLD will be delivered both for events
97 in main debugged process and in cloned processes. As soon as we know there's
98 an event, we get back to calling nonblocking waitpid with and without
101 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
102 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
103 blocked, the signal becomes pending and sigsuspend immediately
104 notices it and returns.
106 Waiting for events in async mode
107 ================================
109 In async mode, GDB should always be ready to handle both user input
110 and target events, so neither blocking waitpid nor sigsuspend are
111 viable options. Instead, we should asynchronously notify the GDB main
112 event loop whenever there's an unprocessed event from the target. We
113 detect asynchronous target events by handling SIGCHLD signals. To
114 notify the event loop about target events, the self-pipe trick is used
115 --- a pipe is registered as waitable event source in the event loop,
116 the event loop select/poll's on the read end of this pipe (as well on
117 other event sources, e.g., stdin), and the SIGCHLD handler writes a
118 byte to this pipe. This is more portable than relying on
119 pselect/ppoll, since on kernels that lack those syscalls, libc
120 emulates them with select/poll+sigprocmask, and that is racy
121 (a.k.a. plain broken).
123 Obviously, if we fail to notify the event loop if there's a target
124 event, it's bad. OTOH, if we notify the event loop when there's no
125 event from the target, linux_nat_wait will detect that there's no real
126 event to report, and return event of type TARGET_WAITKIND_IGNORE.
127 This is mostly harmless, but it will waste time and is better avoided.
129 The main design point is that every time GDB is outside linux-nat.c,
130 we have a SIGCHLD handler installed that is called when something
131 happens to the target and notifies the GDB event loop. Whenever GDB
132 core decides to handle the event, and calls into linux-nat.c, we
133 process things as in sync mode, except that the we never block in
136 While processing an event, we may end up momentarily blocked in
137 waitpid calls. Those waitpid calls, while blocking, are guarantied to
138 return quickly. E.g., in all-stop mode, before reporting to the core
139 that an LWP hit a breakpoint, all LWPs are stopped by sending them
140 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
141 Note that this is different from blocking indefinitely waiting for the
142 next event --- here, we're already handling an event.
147 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
148 signal is not entirely significant; we just need for a signal to be delivered,
149 so that we can intercept it. SIGSTOP's advantage is that it can not be
150 blocked. A disadvantage is that it is not a real-time signal, so it can only
151 be queued once; we do not keep track of other sources of SIGSTOP.
153 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
154 use them, because they have special behavior when the signal is generated -
155 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
156 kills the entire thread group.
158 A delivered SIGSTOP would stop the entire thread group, not just the thread we
159 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
160 cancel it (by PTRACE_CONT without passing SIGSTOP).
162 We could use a real-time signal instead. This would solve those problems; we
163 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
164 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
165 generates it, and there are races with trying to find a signal that is not
169 #define O_LARGEFILE 0
172 /* Unlike other extended result codes, WSTOPSIG (status) on
173 PTRACE_O_TRACESYSGOOD syscall events doesn't return SIGTRAP, but
174 instead SIGTRAP with bit 7 set. */
175 #define SYSCALL_SIGTRAP (SIGTRAP | 0x80)
177 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
178 the use of the multi-threaded target. */
179 static struct target_ops *linux_ops;
180 static struct target_ops linux_ops_saved;
182 /* The method to call, if any, when a new thread is attached. */
183 static void (*linux_nat_new_thread) (struct lwp_info *);
185 /* Hook to call prior to resuming a thread. */
186 static void (*linux_nat_prepare_to_resume) (struct lwp_info *);
188 /* The method to call, if any, when the siginfo object needs to be
189 converted between the layout returned by ptrace, and the layout in
190 the architecture of the inferior. */
191 static int (*linux_nat_siginfo_fixup) (siginfo_t *,
195 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
196 Called by our to_xfer_partial. */
197 static LONGEST (*super_xfer_partial) (struct target_ops *,
199 const char *, gdb_byte *,
203 static int debug_linux_nat;
205 show_debug_linux_nat (struct ui_file *file, int from_tty,
206 struct cmd_list_element *c, const char *value)
208 fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
212 struct simple_pid_list
216 struct simple_pid_list *next;
218 struct simple_pid_list *stopped_pids;
220 /* This variable is a tri-state flag: -1 for unknown, 0 if PTRACE_O_TRACEFORK
221 can not be used, 1 if it can. */
223 static int linux_supports_tracefork_flag = -1;
225 /* This variable is a tri-state flag: -1 for unknown, 0 if
226 PTRACE_O_TRACESYSGOOD can not be used, 1 if it can. */
228 static int linux_supports_tracesysgood_flag = -1;
230 /* If we have PTRACE_O_TRACEFORK, this flag indicates whether we also have
231 PTRACE_O_TRACEVFORKDONE. */
233 static int linux_supports_tracevforkdone_flag = -1;
235 /* Stores the current used ptrace() options. */
236 static int current_ptrace_options = 0;
238 /* Async mode support. */
240 /* The read/write ends of the pipe registered as waitable file in the
242 static int linux_nat_event_pipe[2] = { -1, -1 };
244 /* Flush the event pipe. */
247 async_file_flush (void)
254 ret = read (linux_nat_event_pipe[0], &buf, 1);
256 while (ret >= 0 || (ret == -1 && errno == EINTR));
259 /* Put something (anything, doesn't matter what, or how much) in event
260 pipe, so that the select/poll in the event-loop realizes we have
261 something to process. */
264 async_file_mark (void)
268 /* It doesn't really matter what the pipe contains, as long we end
269 up with something in it. Might as well flush the previous
275 ret = write (linux_nat_event_pipe[1], "+", 1);
277 while (ret == -1 && errno == EINTR);
279 /* Ignore EAGAIN. If the pipe is full, the event loop will already
280 be awakened anyway. */
283 static void linux_nat_async (void (*callback)
284 (enum inferior_event_type event_type,
287 static int kill_lwp (int lwpid, int signo);
289 static int stop_callback (struct lwp_info *lp, void *data);
291 static void block_child_signals (sigset_t *prev_mask);
292 static void restore_child_signals_mask (sigset_t *prev_mask);
295 static struct lwp_info *add_lwp (ptid_t ptid);
296 static void purge_lwp_list (int pid);
297 static void delete_lwp (ptid_t ptid);
298 static struct lwp_info *find_lwp_pid (ptid_t ptid);
301 /* Trivial list manipulation functions to keep track of a list of
302 new stopped processes. */
304 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
306 struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
309 new_pid->status = status;
310 new_pid->next = *listp;
315 in_pid_list_p (struct simple_pid_list *list, int pid)
317 struct simple_pid_list *p;
319 for (p = list; p != NULL; p = p->next)
326 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
328 struct simple_pid_list **p;
330 for (p = listp; *p != NULL; p = &(*p)->next)
331 if ((*p)->pid == pid)
333 struct simple_pid_list *next = (*p)->next;
335 *statusp = (*p)->status;
344 /* A helper function for linux_test_for_tracefork, called after fork (). */
347 linux_tracefork_child (void)
349 ptrace (PTRACE_TRACEME, 0, 0, 0);
350 kill (getpid (), SIGSTOP);
355 /* Wrapper function for waitpid which handles EINTR. */
358 my_waitpid (int pid, int *statusp, int flags)
364 ret = waitpid (pid, statusp, flags);
366 while (ret == -1 && errno == EINTR);
371 /* Determine if PTRACE_O_TRACEFORK can be used to follow fork events.
373 First, we try to enable fork tracing on ORIGINAL_PID. If this fails,
374 we know that the feature is not available. This may change the tracing
375 options for ORIGINAL_PID, but we'll be setting them shortly anyway.
377 However, if it succeeds, we don't know for sure that the feature is
378 available; old versions of PTRACE_SETOPTIONS ignored unknown options. We
379 create a child process, attach to it, use PTRACE_SETOPTIONS to enable
380 fork tracing, and let it fork. If the process exits, we assume that we
381 can't use TRACEFORK; if we get the fork notification, and we can extract
382 the new child's PID, then we assume that we can. */
385 linux_test_for_tracefork (int original_pid)
387 int child_pid, ret, status;
391 /* We don't want those ptrace calls to be interrupted. */
392 block_child_signals (&prev_mask);
394 linux_supports_tracefork_flag = 0;
395 linux_supports_tracevforkdone_flag = 0;
397 ret = ptrace (PTRACE_SETOPTIONS, original_pid, 0, PTRACE_O_TRACEFORK);
400 restore_child_signals_mask (&prev_mask);
406 perror_with_name (("fork"));
409 linux_tracefork_child ();
411 ret = my_waitpid (child_pid, &status, 0);
413 perror_with_name (("waitpid"));
414 else if (ret != child_pid)
415 error (_("linux_test_for_tracefork: waitpid: unexpected result %d."), ret);
416 if (! WIFSTOPPED (status))
417 error (_("linux_test_for_tracefork: waitpid: unexpected status %d."),
420 ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0, PTRACE_O_TRACEFORK);
423 ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
426 warning (_("linux_test_for_tracefork: failed to kill child"));
427 restore_child_signals_mask (&prev_mask);
431 ret = my_waitpid (child_pid, &status, 0);
432 if (ret != child_pid)
433 warning (_("linux_test_for_tracefork: failed "
434 "to wait for killed child"));
435 else if (!WIFSIGNALED (status))
436 warning (_("linux_test_for_tracefork: unexpected "
437 "wait status 0x%x from killed child"), status);
439 restore_child_signals_mask (&prev_mask);
443 /* Check whether PTRACE_O_TRACEVFORKDONE is available. */
444 ret = ptrace (PTRACE_SETOPTIONS, child_pid, 0,
445 PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORKDONE);
446 linux_supports_tracevforkdone_flag = (ret == 0);
448 ret = ptrace (PTRACE_CONT, child_pid, 0, 0);
450 warning (_("linux_test_for_tracefork: failed to resume child"));
452 ret = my_waitpid (child_pid, &status, 0);
454 if (ret == child_pid && WIFSTOPPED (status)
455 && status >> 16 == PTRACE_EVENT_FORK)
458 ret = ptrace (PTRACE_GETEVENTMSG, child_pid, 0, &second_pid);
459 if (ret == 0 && second_pid != 0)
463 linux_supports_tracefork_flag = 1;
464 my_waitpid (second_pid, &second_status, 0);
465 ret = ptrace (PTRACE_KILL, second_pid, 0, 0);
467 warning (_("linux_test_for_tracefork: "
468 "failed to kill second child"));
469 my_waitpid (second_pid, &status, 0);
473 warning (_("linux_test_for_tracefork: unexpected result from waitpid "
474 "(%d, status 0x%x)"), ret, status);
476 ret = ptrace (PTRACE_KILL, child_pid, 0, 0);
478 warning (_("linux_test_for_tracefork: failed to kill child"));
479 my_waitpid (child_pid, &status, 0);
481 restore_child_signals_mask (&prev_mask);
484 /* Determine if PTRACE_O_TRACESYSGOOD can be used to follow syscalls.
486 We try to enable syscall tracing on ORIGINAL_PID. If this fails,
487 we know that the feature is not available. This may change the tracing
488 options for ORIGINAL_PID, but we'll be setting them shortly anyway. */
491 linux_test_for_tracesysgood (int original_pid)
496 /* We don't want those ptrace calls to be interrupted. */
497 block_child_signals (&prev_mask);
499 linux_supports_tracesysgood_flag = 0;
501 ret = ptrace (PTRACE_SETOPTIONS, original_pid, 0, PTRACE_O_TRACESYSGOOD);
505 linux_supports_tracesysgood_flag = 1;
507 restore_child_signals_mask (&prev_mask);
510 /* Determine wether we support PTRACE_O_TRACESYSGOOD option available.
511 This function also sets linux_supports_tracesysgood_flag. */
514 linux_supports_tracesysgood (int pid)
516 if (linux_supports_tracesysgood_flag == -1)
517 linux_test_for_tracesysgood (pid);
518 return linux_supports_tracesysgood_flag;
521 /* Return non-zero iff we have tracefork functionality available.
522 This function also sets linux_supports_tracefork_flag. */
525 linux_supports_tracefork (int pid)
527 if (linux_supports_tracefork_flag == -1)
528 linux_test_for_tracefork (pid);
529 return linux_supports_tracefork_flag;
533 linux_supports_tracevforkdone (int pid)
535 if (linux_supports_tracefork_flag == -1)
536 linux_test_for_tracefork (pid);
537 return linux_supports_tracevforkdone_flag;
541 linux_enable_tracesysgood (ptid_t ptid)
543 int pid = ptid_get_lwp (ptid);
546 pid = ptid_get_pid (ptid);
548 if (linux_supports_tracesysgood (pid) == 0)
551 current_ptrace_options |= PTRACE_O_TRACESYSGOOD;
553 ptrace (PTRACE_SETOPTIONS, pid, 0, current_ptrace_options);
558 linux_enable_event_reporting (ptid_t ptid)
560 int pid = ptid_get_lwp (ptid);
563 pid = ptid_get_pid (ptid);
565 if (! linux_supports_tracefork (pid))
568 current_ptrace_options |= PTRACE_O_TRACEFORK | PTRACE_O_TRACEVFORK
569 | PTRACE_O_TRACEEXEC | PTRACE_O_TRACECLONE;
571 if (linux_supports_tracevforkdone (pid))
572 current_ptrace_options |= PTRACE_O_TRACEVFORKDONE;
574 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to support
575 read-only process state. */
577 ptrace (PTRACE_SETOPTIONS, pid, 0, current_ptrace_options);
581 linux_child_post_attach (int pid)
583 linux_enable_event_reporting (pid_to_ptid (pid));
584 linux_enable_tracesysgood (pid_to_ptid (pid));
588 linux_child_post_startup_inferior (ptid_t ptid)
590 linux_enable_event_reporting (ptid);
591 linux_enable_tracesysgood (ptid);
594 /* Return the number of known LWPs in the tgid given by PID. */
602 for (lp = lwp_list; lp; lp = lp->next)
603 if (ptid_get_pid (lp->ptid) == pid)
609 /* Call delete_lwp with prototype compatible for make_cleanup. */
612 delete_lwp_cleanup (void *lp_voidp)
614 struct lwp_info *lp = lp_voidp;
616 delete_lwp (lp->ptid);
620 linux_child_follow_fork (struct target_ops *ops, int follow_child)
624 int parent_pid, child_pid;
626 block_child_signals (&prev_mask);
628 has_vforked = (inferior_thread ()->pending_follow.kind
629 == TARGET_WAITKIND_VFORKED);
630 parent_pid = ptid_get_lwp (inferior_ptid);
632 parent_pid = ptid_get_pid (inferior_ptid);
633 child_pid = PIDGET (inferior_thread ()->pending_follow.value.related_pid);
636 linux_enable_event_reporting (pid_to_ptid (child_pid));
639 && !non_stop /* Non-stop always resumes both branches. */
640 && (!target_is_async_p () || sync_execution)
641 && !(follow_child || detach_fork || sched_multi))
643 /* The parent stays blocked inside the vfork syscall until the
644 child execs or exits. If we don't let the child run, then
645 the parent stays blocked. If we're telling the parent to run
646 in the foreground, the user will not be able to ctrl-c to get
647 back the terminal, effectively hanging the debug session. */
648 fprintf_filtered (gdb_stderr, _("\
649 Can not resume the parent process over vfork in the foreground while\n\
650 holding the child stopped. Try \"set detach-on-fork\" or \
651 \"set schedule-multiple\".\n"));
652 /* FIXME output string > 80 columns. */
658 struct lwp_info *child_lp = NULL;
660 /* We're already attached to the parent, by default. */
662 /* Detach new forked process? */
665 struct cleanup *old_chain;
667 /* Before detaching from the child, remove all breakpoints
668 from it. If we forked, then this has already been taken
669 care of by infrun.c. If we vforked however, any
670 breakpoint inserted in the parent is visible in the
671 child, even those added while stopped in a vfork
672 catchpoint. This will remove the breakpoints from the
673 parent also, but they'll be reinserted below. */
676 /* keep breakpoints list in sync. */
677 remove_breakpoints_pid (GET_PID (inferior_ptid));
680 if (info_verbose || debug_linux_nat)
682 target_terminal_ours ();
683 fprintf_filtered (gdb_stdlog,
684 "Detaching after fork from "
685 "child process %d.\n",
689 old_chain = save_inferior_ptid ();
690 inferior_ptid = ptid_build (child_pid, child_pid, 0);
692 child_lp = add_lwp (inferior_ptid);
693 child_lp->stopped = 1;
694 child_lp->last_resume_kind = resume_stop;
695 make_cleanup (delete_lwp_cleanup, child_lp);
697 /* CHILD_LP has new PID, therefore linux_nat_new_thread is not called for it.
698 See i386_inferior_data_get for the Linux kernel specifics.
699 Ensure linux_nat_prepare_to_resume will reset the hardware debug
700 registers. It is done by the linux_nat_new_thread call, which is
701 being skipped in add_lwp above for the first lwp of a pid. */
702 gdb_assert (num_lwps (GET_PID (child_lp->ptid)) == 1);
703 if (linux_nat_new_thread != NULL)
704 linux_nat_new_thread (child_lp);
706 if (linux_nat_prepare_to_resume != NULL)
707 linux_nat_prepare_to_resume (child_lp);
708 ptrace (PTRACE_DETACH, child_pid, 0, 0);
710 do_cleanups (old_chain);
714 struct inferior *parent_inf, *child_inf;
715 struct cleanup *old_chain;
717 /* Add process to GDB's tables. */
718 child_inf = add_inferior (child_pid);
720 parent_inf = current_inferior ();
721 child_inf->attach_flag = parent_inf->attach_flag;
722 copy_terminal_info (child_inf, parent_inf);
724 old_chain = save_inferior_ptid ();
725 save_current_program_space ();
727 inferior_ptid = ptid_build (child_pid, child_pid, 0);
728 add_thread (inferior_ptid);
729 child_lp = add_lwp (inferior_ptid);
730 child_lp->stopped = 1;
731 child_lp->last_resume_kind = resume_stop;
732 child_inf->symfile_flags = SYMFILE_NO_READ;
734 /* If this is a vfork child, then the address-space is
735 shared with the parent. */
738 child_inf->pspace = parent_inf->pspace;
739 child_inf->aspace = parent_inf->aspace;
741 /* The parent will be frozen until the child is done
742 with the shared region. Keep track of the
744 child_inf->vfork_parent = parent_inf;
745 child_inf->pending_detach = 0;
746 parent_inf->vfork_child = child_inf;
747 parent_inf->pending_detach = 0;
751 child_inf->aspace = new_address_space ();
752 child_inf->pspace = add_program_space (child_inf->aspace);
753 child_inf->removable = 1;
754 set_current_program_space (child_inf->pspace);
755 clone_program_space (child_inf->pspace, parent_inf->pspace);
757 /* Let the shared library layer (solib-svr4) learn about
758 this new process, relocate the cloned exec, pull in
759 shared libraries, and install the solib event
760 breakpoint. If a "cloned-VM" event was propagated
761 better throughout the core, this wouldn't be
763 solib_create_inferior_hook (0);
766 /* Let the thread_db layer learn about this new process. */
767 check_for_thread_db ();
769 do_cleanups (old_chain);
774 struct lwp_info *parent_lp;
775 struct inferior *parent_inf;
777 parent_inf = current_inferior ();
779 /* If we detached from the child, then we have to be careful
780 to not insert breakpoints in the parent until the child
781 is done with the shared memory region. However, if we're
782 staying attached to the child, then we can and should
783 insert breakpoints, so that we can debug it. A
784 subsequent child exec or exit is enough to know when does
785 the child stops using the parent's address space. */
786 parent_inf->waiting_for_vfork_done = detach_fork;
787 parent_inf->pspace->breakpoints_not_allowed = detach_fork;
789 parent_lp = find_lwp_pid (pid_to_ptid (parent_pid));
790 gdb_assert (linux_supports_tracefork_flag >= 0);
792 if (linux_supports_tracevforkdone (0))
795 fprintf_unfiltered (gdb_stdlog,
796 "LCFF: waiting for VFORK_DONE on %d\n",
798 parent_lp->stopped = 1;
800 /* We'll handle the VFORK_DONE event like any other
801 event, in target_wait. */
805 /* We can't insert breakpoints until the child has
806 finished with the shared memory region. We need to
807 wait until that happens. Ideal would be to just
809 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
810 - waitpid (parent_pid, &status, __WALL);
811 However, most architectures can't handle a syscall
812 being traced on the way out if it wasn't traced on
815 We might also think to loop, continuing the child
816 until it exits or gets a SIGTRAP. One problem is
817 that the child might call ptrace with PTRACE_TRACEME.
819 There's no simple and reliable way to figure out when
820 the vforked child will be done with its copy of the
821 shared memory. We could step it out of the syscall,
822 two instructions, let it go, and then single-step the
823 parent once. When we have hardware single-step, this
824 would work; with software single-step it could still
825 be made to work but we'd have to be able to insert
826 single-step breakpoints in the child, and we'd have
827 to insert -just- the single-step breakpoint in the
828 parent. Very awkward.
830 In the end, the best we can do is to make sure it
831 runs for a little while. Hopefully it will be out of
832 range of any breakpoints we reinsert. Usually this
833 is only the single-step breakpoint at vfork's return
837 fprintf_unfiltered (gdb_stdlog,
838 "LCFF: no VFORK_DONE "
839 "support, sleeping a bit\n");
843 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
844 and leave it pending. The next linux_nat_resume call
845 will notice a pending event, and bypasses actually
846 resuming the inferior. */
847 parent_lp->status = 0;
848 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
849 parent_lp->stopped = 1;
851 /* If we're in async mode, need to tell the event loop
852 there's something here to process. */
853 if (target_can_async_p ())
860 struct inferior *parent_inf, *child_inf;
861 struct lwp_info *child_lp;
862 struct program_space *parent_pspace;
864 if (info_verbose || debug_linux_nat)
866 target_terminal_ours ();
868 fprintf_filtered (gdb_stdlog,
869 _("Attaching after process %d "
870 "vfork to child process %d.\n"),
871 parent_pid, child_pid);
873 fprintf_filtered (gdb_stdlog,
874 _("Attaching after process %d "
875 "fork to child process %d.\n"),
876 parent_pid, child_pid);
879 /* Add the new inferior first, so that the target_detach below
880 doesn't unpush the target. */
882 child_inf = add_inferior (child_pid);
884 parent_inf = current_inferior ();
885 child_inf->attach_flag = parent_inf->attach_flag;
886 copy_terminal_info (child_inf, parent_inf);
888 parent_pspace = parent_inf->pspace;
890 /* If we're vforking, we want to hold on to the parent until the
891 child exits or execs. At child exec or exit time we can
892 remove the old breakpoints from the parent and detach or
893 resume debugging it. Otherwise, detach the parent now; we'll
894 want to reuse it's program/address spaces, but we can't set
895 them to the child before removing breakpoints from the
896 parent, otherwise, the breakpoints module could decide to
897 remove breakpoints from the wrong process (since they'd be
898 assigned to the same address space). */
902 gdb_assert (child_inf->vfork_parent == NULL);
903 gdb_assert (parent_inf->vfork_child == NULL);
904 child_inf->vfork_parent = parent_inf;
905 child_inf->pending_detach = 0;
906 parent_inf->vfork_child = child_inf;
907 parent_inf->pending_detach = detach_fork;
908 parent_inf->waiting_for_vfork_done = 0;
910 else if (detach_fork)
911 target_detach (NULL, 0);
913 /* Note that the detach above makes PARENT_INF dangling. */
915 /* Add the child thread to the appropriate lists, and switch to
916 this new thread, before cloning the program space, and
917 informing the solib layer about this new process. */
919 inferior_ptid = ptid_build (child_pid, child_pid, 0);
920 add_thread (inferior_ptid);
921 child_lp = add_lwp (inferior_ptid);
922 child_lp->stopped = 1;
923 child_lp->last_resume_kind = resume_stop;
925 /* If this is a vfork child, then the address-space is shared
926 with the parent. If we detached from the parent, then we can
927 reuse the parent's program/address spaces. */
928 if (has_vforked || detach_fork)
930 child_inf->pspace = parent_pspace;
931 child_inf->aspace = child_inf->pspace->aspace;
935 child_inf->aspace = new_address_space ();
936 child_inf->pspace = add_program_space (child_inf->aspace);
937 child_inf->removable = 1;
938 child_inf->symfile_flags = SYMFILE_NO_READ;
939 set_current_program_space (child_inf->pspace);
940 clone_program_space (child_inf->pspace, parent_pspace);
942 /* Let the shared library layer (solib-svr4) learn about
943 this new process, relocate the cloned exec, pull in
944 shared libraries, and install the solib event breakpoint.
945 If a "cloned-VM" event was propagated better throughout
946 the core, this wouldn't be required. */
947 solib_create_inferior_hook (0);
950 /* Let the thread_db layer learn about this new process. */
951 check_for_thread_db ();
954 restore_child_signals_mask (&prev_mask);
960 linux_child_insert_fork_catchpoint (int pid)
962 return !linux_supports_tracefork (pid);
966 linux_child_remove_fork_catchpoint (int pid)
972 linux_child_insert_vfork_catchpoint (int pid)
974 return !linux_supports_tracefork (pid);
978 linux_child_remove_vfork_catchpoint (int pid)
984 linux_child_insert_exec_catchpoint (int pid)
986 return !linux_supports_tracefork (pid);
990 linux_child_remove_exec_catchpoint (int pid)
996 linux_child_set_syscall_catchpoint (int pid, int needed, int any_count,
997 int table_size, int *table)
999 if (!linux_supports_tracesysgood (pid))
1002 /* On GNU/Linux, we ignore the arguments. It means that we only
1003 enable the syscall catchpoints, but do not disable them.
1005 Also, we do not use the `table' information because we do not
1006 filter system calls here. We let GDB do the logic for us. */
1010 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
1011 are processes sharing the same VM space. A multi-threaded process
1012 is basically a group of such processes. However, such a grouping
1013 is almost entirely a user-space issue; the kernel doesn't enforce
1014 such a grouping at all (this might change in the future). In
1015 general, we'll rely on the threads library (i.e. the GNU/Linux
1016 Threads library) to provide such a grouping.
1018 It is perfectly well possible to write a multi-threaded application
1019 without the assistance of a threads library, by using the clone
1020 system call directly. This module should be able to give some
1021 rudimentary support for debugging such applications if developers
1022 specify the CLONE_PTRACE flag in the clone system call, and are
1023 using the Linux kernel 2.4 or above.
1025 Note that there are some peculiarities in GNU/Linux that affect
1028 - In general one should specify the __WCLONE flag to waitpid in
1029 order to make it report events for any of the cloned processes
1030 (and leave it out for the initial process). However, if a cloned
1031 process has exited the exit status is only reported if the
1032 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
1033 we cannot use it since GDB must work on older systems too.
1035 - When a traced, cloned process exits and is waited for by the
1036 debugger, the kernel reassigns it to the original parent and
1037 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
1038 library doesn't notice this, which leads to the "zombie problem":
1039 When debugged a multi-threaded process that spawns a lot of
1040 threads will run out of processes, even if the threads exit,
1041 because the "zombies" stay around. */
1043 /* List of known LWPs. */
1044 struct lwp_info *lwp_list;
1047 /* Original signal mask. */
1048 static sigset_t normal_mask;
1050 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
1051 _initialize_linux_nat. */
1052 static sigset_t suspend_mask;
1054 /* Signals to block to make that sigsuspend work. */
1055 static sigset_t blocked_mask;
1057 /* SIGCHLD action. */
1058 struct sigaction sigchld_action;
1060 /* Block child signals (SIGCHLD and linux threads signals), and store
1061 the previous mask in PREV_MASK. */
1064 block_child_signals (sigset_t *prev_mask)
1066 /* Make sure SIGCHLD is blocked. */
1067 if (!sigismember (&blocked_mask, SIGCHLD))
1068 sigaddset (&blocked_mask, SIGCHLD);
1070 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
1073 /* Restore child signals mask, previously returned by
1074 block_child_signals. */
1077 restore_child_signals_mask (sigset_t *prev_mask)
1079 sigprocmask (SIG_SETMASK, prev_mask, NULL);
1082 /* Mask of signals to pass directly to the inferior. */
1083 static sigset_t pass_mask;
1085 /* Update signals to pass to the inferior. */
1087 linux_nat_pass_signals (int numsigs, unsigned char *pass_signals)
1091 sigemptyset (&pass_mask);
1093 for (signo = 1; signo < NSIG; signo++)
1095 int target_signo = target_signal_from_host (signo);
1096 if (target_signo < numsigs && pass_signals[target_signo])
1097 sigaddset (&pass_mask, signo);
1103 /* Prototypes for local functions. */
1104 static int stop_wait_callback (struct lwp_info *lp, void *data);
1105 static int linux_thread_alive (ptid_t ptid);
1106 static char *linux_child_pid_to_exec_file (int pid);
1109 /* Convert wait status STATUS to a string. Used for printing debug
1113 status_to_str (int status)
1115 static char buf[64];
1117 if (WIFSTOPPED (status))
1119 if (WSTOPSIG (status) == SYSCALL_SIGTRAP)
1120 snprintf (buf, sizeof (buf), "%s (stopped at syscall)",
1121 strsignal (SIGTRAP));
1123 snprintf (buf, sizeof (buf), "%s (stopped)",
1124 strsignal (WSTOPSIG (status)));
1126 else if (WIFSIGNALED (status))
1127 snprintf (buf, sizeof (buf), "%s (terminated)",
1128 strsignal (WTERMSIG (status)));
1130 snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status));
1135 /* Destroy and free LP. */
1138 lwp_free (struct lwp_info *lp)
1140 xfree (lp->arch_private);
1144 /* Remove all LWPs belong to PID from the lwp list. */
1147 purge_lwp_list (int pid)
1149 struct lwp_info *lp, *lpprev, *lpnext;
1153 for (lp = lwp_list; lp; lp = lpnext)
1157 if (ptid_get_pid (lp->ptid) == pid)
1160 lwp_list = lp->next;
1162 lpprev->next = lp->next;
1171 /* Add the LWP specified by PID to the list. Return a pointer to the
1172 structure describing the new LWP. The LWP should already be stopped
1173 (with an exception for the very first LWP). */
1175 static struct lwp_info *
1176 add_lwp (ptid_t ptid)
1178 struct lwp_info *lp;
1180 gdb_assert (is_lwp (ptid));
1182 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
1184 memset (lp, 0, sizeof (struct lwp_info));
1186 lp->last_resume_kind = resume_continue;
1187 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
1192 lp->next = lwp_list;
1195 /* Let the arch specific bits know about this new thread. Current
1196 clients of this callback take the opportunity to install
1197 watchpoints in the new thread. Don't do this for the first
1198 thread though. If we're spawning a child ("run"), the thread
1199 executes the shell wrapper first, and we shouldn't touch it until
1200 it execs the program we want to debug. For "attach", it'd be
1201 okay to call the callback, but it's not necessary, because
1202 watchpoints can't yet have been inserted into the inferior. */
1203 if (num_lwps (GET_PID (ptid)) > 1 && linux_nat_new_thread != NULL)
1204 linux_nat_new_thread (lp);
1209 /* Remove the LWP specified by PID from the list. */
1212 delete_lwp (ptid_t ptid)
1214 struct lwp_info *lp, *lpprev;
1218 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
1219 if (ptid_equal (lp->ptid, ptid))
1226 lpprev->next = lp->next;
1228 lwp_list = lp->next;
1233 /* Return a pointer to the structure describing the LWP corresponding
1234 to PID. If no corresponding LWP could be found, return NULL. */
1236 static struct lwp_info *
1237 find_lwp_pid (ptid_t ptid)
1239 struct lwp_info *lp;
1243 lwp = GET_LWP (ptid);
1245 lwp = GET_PID (ptid);
1247 for (lp = lwp_list; lp; lp = lp->next)
1248 if (lwp == GET_LWP (lp->ptid))
1254 /* Call CALLBACK with its second argument set to DATA for every LWP in
1255 the list. If CALLBACK returns 1 for a particular LWP, return a
1256 pointer to the structure describing that LWP immediately.
1257 Otherwise return NULL. */
1260 iterate_over_lwps (ptid_t filter,
1261 int (*callback) (struct lwp_info *, void *),
1264 struct lwp_info *lp, *lpnext;
1266 for (lp = lwp_list; lp; lp = lpnext)
1270 if (ptid_match (lp->ptid, filter))
1272 if ((*callback) (lp, data))
1280 /* Iterate like iterate_over_lwps does except when forking-off a child call
1281 CALLBACK with CALLBACK_DATA specifically only for that new child PID. */
1284 linux_nat_iterate_watchpoint_lwps
1285 (linux_nat_iterate_watchpoint_lwps_ftype callback, void *callback_data)
1287 int inferior_pid = ptid_get_pid (inferior_ptid);
1288 struct inferior *inf = current_inferior ();
1290 if (inf->pid == inferior_pid)
1292 /* Iterate all the threads of the current inferior. Without specifying
1293 INFERIOR_PID it would iterate all threads of all inferiors, which is
1294 inappropriate for watchpoints. */
1296 iterate_over_lwps (pid_to_ptid (inferior_pid), callback, callback_data);
1300 /* Detaching a new child PID temporarily present in INFERIOR_PID. */
1302 struct lwp_info *child_lp;
1303 struct cleanup *old_chain;
1304 pid_t child_pid = GET_PID (inferior_ptid);
1305 ptid_t child_ptid = ptid_build (child_pid, child_pid, 0);
1307 gdb_assert (!is_lwp (inferior_ptid));
1308 gdb_assert (find_lwp_pid (child_ptid) == NULL);
1309 child_lp = add_lwp (child_ptid);
1310 child_lp->stopped = 1;
1311 child_lp->last_resume_kind = resume_stop;
1312 old_chain = make_cleanup (delete_lwp_cleanup, child_lp);
1314 callback (child_lp, callback_data);
1316 do_cleanups (old_chain);
1320 /* Update our internal state when changing from one checkpoint to
1321 another indicated by NEW_PTID. We can only switch single-threaded
1322 applications, so we only create one new LWP, and the previous list
1326 linux_nat_switch_fork (ptid_t new_ptid)
1328 struct lwp_info *lp;
1330 purge_lwp_list (GET_PID (inferior_ptid));
1332 lp = add_lwp (new_ptid);
1335 /* This changes the thread's ptid while preserving the gdb thread
1336 num. Also changes the inferior pid, while preserving the
1338 thread_change_ptid (inferior_ptid, new_ptid);
1340 /* We've just told GDB core that the thread changed target id, but,
1341 in fact, it really is a different thread, with different register
1343 registers_changed ();
1346 /* Handle the exit of a single thread LP. */
1349 exit_lwp (struct lwp_info *lp)
1351 struct thread_info *th = find_thread_ptid (lp->ptid);
1355 if (print_thread_events)
1356 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
1358 delete_thread (lp->ptid);
1361 delete_lwp (lp->ptid);
1364 /* Wait for the LWP specified by LP, which we have just attached to.
1365 Returns a wait status for that LWP, to cache. */
1368 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
1371 pid_t new_pid, pid = GET_LWP (ptid);
1374 if (linux_proc_pid_is_stopped (pid))
1376 if (debug_linux_nat)
1377 fprintf_unfiltered (gdb_stdlog,
1378 "LNPAW: Attaching to a stopped process\n");
1380 /* The process is definitely stopped. It is in a job control
1381 stop, unless the kernel predates the TASK_STOPPED /
1382 TASK_TRACED distinction, in which case it might be in a
1383 ptrace stop. Make sure it is in a ptrace stop; from there we
1384 can kill it, signal it, et cetera.
1386 First make sure there is a pending SIGSTOP. Since we are
1387 already attached, the process can not transition from stopped
1388 to running without a PTRACE_CONT; so we know this signal will
1389 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1390 probably already in the queue (unless this kernel is old
1391 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1392 is not an RT signal, it can only be queued once. */
1393 kill_lwp (pid, SIGSTOP);
1395 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1396 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1397 ptrace (PTRACE_CONT, pid, 0, 0);
1400 /* Make sure the initial process is stopped. The user-level threads
1401 layer might want to poke around in the inferior, and that won't
1402 work if things haven't stabilized yet. */
1403 new_pid = my_waitpid (pid, &status, 0);
1404 if (new_pid == -1 && errno == ECHILD)
1407 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
1409 /* Try again with __WCLONE to check cloned processes. */
1410 new_pid = my_waitpid (pid, &status, __WCLONE);
1414 gdb_assert (pid == new_pid);
1416 if (!WIFSTOPPED (status))
1418 /* The pid we tried to attach has apparently just exited. */
1419 if (debug_linux_nat)
1420 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
1421 pid, status_to_str (status));
1425 if (WSTOPSIG (status) != SIGSTOP)
1428 if (debug_linux_nat)
1429 fprintf_unfiltered (gdb_stdlog,
1430 "LNPAW: Received %s after attaching\n",
1431 status_to_str (status));
1437 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1438 the new LWP could not be attached, or 1 if we're already auto
1439 attached to this thread, but haven't processed the
1440 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1441 its existance, without considering it an error. */
1444 lin_lwp_attach_lwp (ptid_t ptid)
1446 struct lwp_info *lp;
1450 gdb_assert (is_lwp (ptid));
1452 block_child_signals (&prev_mask);
1454 lp = find_lwp_pid (ptid);
1455 lwpid = GET_LWP (ptid);
1457 /* We assume that we're already attached to any LWP that has an id
1458 equal to the overall process id, and to any LWP that is already
1459 in our list of LWPs. If we're not seeing exit events from threads
1460 and we've had PID wraparound since we last tried to stop all threads,
1461 this assumption might be wrong; fortunately, this is very unlikely
1463 if (lwpid != GET_PID (ptid) && lp == NULL)
1465 int status, cloned = 0, signalled = 0;
1467 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1469 if (linux_supports_tracefork_flag)
1471 /* If we haven't stopped all threads when we get here,
1472 we may have seen a thread listed in thread_db's list,
1473 but not processed the PTRACE_EVENT_CLONE yet. If
1474 that's the case, ignore this new thread, and let
1475 normal event handling discover it later. */
1476 if (in_pid_list_p (stopped_pids, lwpid))
1478 /* We've already seen this thread stop, but we
1479 haven't seen the PTRACE_EVENT_CLONE extended
1481 restore_child_signals_mask (&prev_mask);
1489 /* See if we've got a stop for this new child
1490 pending. If so, we're already attached. */
1491 new_pid = my_waitpid (lwpid, &status, WNOHANG);
1492 if (new_pid == -1 && errno == ECHILD)
1493 new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
1496 if (WIFSTOPPED (status))
1497 add_to_pid_list (&stopped_pids, lwpid, status);
1499 restore_child_signals_mask (&prev_mask);
1505 /* If we fail to attach to the thread, issue a warning,
1506 but continue. One way this can happen is if thread
1507 creation is interrupted; as of Linux kernel 2.6.19, a
1508 bug may place threads in the thread list and then fail
1510 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1511 safe_strerror (errno));
1512 restore_child_signals_mask (&prev_mask);
1516 if (debug_linux_nat)
1517 fprintf_unfiltered (gdb_stdlog,
1518 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1519 target_pid_to_str (ptid));
1521 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1522 if (!WIFSTOPPED (status))
1524 restore_child_signals_mask (&prev_mask);
1528 lp = add_lwp (ptid);
1530 lp->cloned = cloned;
1531 lp->signalled = signalled;
1532 if (WSTOPSIG (status) != SIGSTOP)
1535 lp->status = status;
1538 target_post_attach (GET_LWP (lp->ptid));
1540 if (debug_linux_nat)
1542 fprintf_unfiltered (gdb_stdlog,
1543 "LLAL: waitpid %s received %s\n",
1544 target_pid_to_str (ptid),
1545 status_to_str (status));
1550 /* We assume that the LWP representing the original process is
1551 already stopped. Mark it as stopped in the data structure
1552 that the GNU/linux ptrace layer uses to keep track of
1553 threads. Note that this won't have already been done since
1554 the main thread will have, we assume, been stopped by an
1555 attach from a different layer. */
1557 lp = add_lwp (ptid);
1561 lp->last_resume_kind = resume_stop;
1562 restore_child_signals_mask (&prev_mask);
1567 linux_nat_create_inferior (struct target_ops *ops,
1568 char *exec_file, char *allargs, char **env,
1571 #ifdef HAVE_PERSONALITY
1572 int personality_orig = 0, personality_set = 0;
1573 #endif /* HAVE_PERSONALITY */
1575 /* The fork_child mechanism is synchronous and calls target_wait, so
1576 we have to mask the async mode. */
1578 #ifdef HAVE_PERSONALITY
1579 if (disable_randomization)
1582 personality_orig = personality (0xffffffff);
1583 if (errno == 0 && !(personality_orig & ADDR_NO_RANDOMIZE))
1585 personality_set = 1;
1586 personality (personality_orig | ADDR_NO_RANDOMIZE);
1588 if (errno != 0 || (personality_set
1589 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE)))
1590 warning (_("Error disabling address space randomization: %s"),
1591 safe_strerror (errno));
1593 #endif /* HAVE_PERSONALITY */
1595 /* Make sure we report all signals during startup. */
1596 linux_nat_pass_signals (0, NULL);
1598 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1600 #ifdef HAVE_PERSONALITY
1601 if (personality_set)
1604 personality (personality_orig);
1606 warning (_("Error restoring address space randomization: %s"),
1607 safe_strerror (errno));
1609 #endif /* HAVE_PERSONALITY */
1613 linux_nat_attach (struct target_ops *ops, char *args, int from_tty)
1615 struct lwp_info *lp;
1618 volatile struct gdb_exception ex;
1620 /* Make sure we report all signals during attach. */
1621 linux_nat_pass_signals (0, NULL);
1623 TRY_CATCH (ex, RETURN_MASK_ERROR)
1625 linux_ops->to_attach (ops, args, from_tty);
1629 pid_t pid = parse_pid_to_attach (args);
1630 struct buffer buffer;
1631 char *message, *buffer_s;
1633 message = xstrdup (ex.message);
1634 make_cleanup (xfree, message);
1636 buffer_init (&buffer);
1637 linux_ptrace_attach_warnings (pid, &buffer);
1639 buffer_grow_str0 (&buffer, "");
1640 buffer_s = buffer_finish (&buffer);
1641 make_cleanup (xfree, buffer_s);
1643 throw_error (ex.error, "%s%s", buffer_s, message);
1646 /* The ptrace base target adds the main thread with (pid,0,0)
1647 format. Decorate it with lwp info. */
1648 ptid = BUILD_LWP (GET_PID (inferior_ptid), GET_PID (inferior_ptid));
1649 thread_change_ptid (inferior_ptid, ptid);
1651 /* Add the initial process as the first LWP to the list. */
1652 lp = add_lwp (ptid);
1654 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1656 if (!WIFSTOPPED (status))
1658 if (WIFEXITED (status))
1660 int exit_code = WEXITSTATUS (status);
1662 target_terminal_ours ();
1663 target_mourn_inferior ();
1665 error (_("Unable to attach: program exited normally."));
1667 error (_("Unable to attach: program exited with code %d."),
1670 else if (WIFSIGNALED (status))
1672 enum target_signal signo;
1674 target_terminal_ours ();
1675 target_mourn_inferior ();
1677 signo = target_signal_from_host (WTERMSIG (status));
1678 error (_("Unable to attach: program terminated with signal "
1680 target_signal_to_name (signo),
1681 target_signal_to_string (signo));
1684 internal_error (__FILE__, __LINE__,
1685 _("unexpected status %d for PID %ld"),
1686 status, (long) GET_LWP (ptid));
1691 /* Save the wait status to report later. */
1693 if (debug_linux_nat)
1694 fprintf_unfiltered (gdb_stdlog,
1695 "LNA: waitpid %ld, saving status %s\n",
1696 (long) GET_PID (lp->ptid), status_to_str (status));
1698 lp->status = status;
1700 if (target_can_async_p ())
1701 target_async (inferior_event_handler, 0);
1704 /* Get pending status of LP. */
1706 get_pending_status (struct lwp_info *lp, int *status)
1708 enum target_signal signo = TARGET_SIGNAL_0;
1710 /* If we paused threads momentarily, we may have stored pending
1711 events in lp->status or lp->waitstatus (see stop_wait_callback),
1712 and GDB core hasn't seen any signal for those threads.
1713 Otherwise, the last signal reported to the core is found in the
1714 thread object's stop_signal.
1716 There's a corner case that isn't handled here at present. Only
1717 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1718 stop_signal make sense as a real signal to pass to the inferior.
1719 Some catchpoint related events, like
1720 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1721 to TARGET_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1722 those traps are debug API (ptrace in our case) related and
1723 induced; the inferior wouldn't see them if it wasn't being
1724 traced. Hence, we should never pass them to the inferior, even
1725 when set to pass state. Since this corner case isn't handled by
1726 infrun.c when proceeding with a signal, for consistency, neither
1727 do we handle it here (or elsewhere in the file we check for
1728 signal pass state). Normally SIGTRAP isn't set to pass state, so
1729 this is really a corner case. */
1731 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1732 signo = TARGET_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1733 else if (lp->status)
1734 signo = target_signal_from_host (WSTOPSIG (lp->status));
1735 else if (non_stop && !is_executing (lp->ptid))
1737 struct thread_info *tp = find_thread_ptid (lp->ptid);
1739 signo = tp->suspend.stop_signal;
1743 struct target_waitstatus last;
1746 get_last_target_status (&last_ptid, &last);
1748 if (GET_LWP (lp->ptid) == GET_LWP (last_ptid))
1750 struct thread_info *tp = find_thread_ptid (lp->ptid);
1752 signo = tp->suspend.stop_signal;
1758 if (signo == TARGET_SIGNAL_0)
1760 if (debug_linux_nat)
1761 fprintf_unfiltered (gdb_stdlog,
1762 "GPT: lwp %s has no pending signal\n",
1763 target_pid_to_str (lp->ptid));
1765 else if (!signal_pass_state (signo))
1767 if (debug_linux_nat)
1768 fprintf_unfiltered (gdb_stdlog,
1769 "GPT: lwp %s had signal %s, "
1770 "but it is in no pass state\n",
1771 target_pid_to_str (lp->ptid),
1772 target_signal_to_string (signo));
1776 *status = W_STOPCODE (target_signal_to_host (signo));
1778 if (debug_linux_nat)
1779 fprintf_unfiltered (gdb_stdlog,
1780 "GPT: lwp %s has pending signal %s\n",
1781 target_pid_to_str (lp->ptid),
1782 target_signal_to_string (signo));
1789 detach_callback (struct lwp_info *lp, void *data)
1791 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1793 if (debug_linux_nat && lp->status)
1794 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1795 strsignal (WSTOPSIG (lp->status)),
1796 target_pid_to_str (lp->ptid));
1798 /* If there is a pending SIGSTOP, get rid of it. */
1801 if (debug_linux_nat)
1802 fprintf_unfiltered (gdb_stdlog,
1803 "DC: Sending SIGCONT to %s\n",
1804 target_pid_to_str (lp->ptid));
1806 kill_lwp (GET_LWP (lp->ptid), SIGCONT);
1810 /* We don't actually detach from the LWP that has an id equal to the
1811 overall process id just yet. */
1812 if (GET_LWP (lp->ptid) != GET_PID (lp->ptid))
1816 /* Pass on any pending signal for this LWP. */
1817 get_pending_status (lp, &status);
1819 if (linux_nat_prepare_to_resume != NULL)
1820 linux_nat_prepare_to_resume (lp);
1822 if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0,
1823 WSTOPSIG (status)) < 0)
1824 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1825 safe_strerror (errno));
1827 if (debug_linux_nat)
1828 fprintf_unfiltered (gdb_stdlog,
1829 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1830 target_pid_to_str (lp->ptid),
1831 strsignal (WSTOPSIG (status)));
1833 delete_lwp (lp->ptid);
1840 linux_nat_detach (struct target_ops *ops, char *args, int from_tty)
1844 struct lwp_info *main_lwp;
1846 pid = GET_PID (inferior_ptid);
1848 if (target_can_async_p ())
1849 linux_nat_async (NULL, 0);
1851 /* Stop all threads before detaching. ptrace requires that the
1852 thread is stopped to sucessfully detach. */
1853 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1854 /* ... and wait until all of them have reported back that
1855 they're no longer running. */
1856 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1858 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1860 /* Only the initial process should be left right now. */
1861 gdb_assert (num_lwps (GET_PID (inferior_ptid)) == 1);
1863 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1865 /* Pass on any pending signal for the last LWP. */
1866 if ((args == NULL || *args == '\0')
1867 && get_pending_status (main_lwp, &status) != -1
1868 && WIFSTOPPED (status))
1870 /* Put the signal number in ARGS so that inf_ptrace_detach will
1871 pass it along with PTRACE_DETACH. */
1873 sprintf (args, "%d", (int) WSTOPSIG (status));
1874 if (debug_linux_nat)
1875 fprintf_unfiltered (gdb_stdlog,
1876 "LND: Sending signal %s to %s\n",
1878 target_pid_to_str (main_lwp->ptid));
1881 if (linux_nat_prepare_to_resume != NULL)
1882 linux_nat_prepare_to_resume (main_lwp);
1883 delete_lwp (main_lwp->ptid);
1885 if (forks_exist_p ())
1887 /* Multi-fork case. The current inferior_ptid is being detached
1888 from, but there are other viable forks to debug. Detach from
1889 the current fork, and context-switch to the first
1891 linux_fork_detach (args, from_tty);
1893 if (non_stop && target_can_async_p ())
1894 target_async (inferior_event_handler, 0);
1897 linux_ops->to_detach (ops, args, from_tty);
1903 resume_lwp (struct lwp_info *lp, int step)
1907 struct inferior *inf = find_inferior_pid (GET_PID (lp->ptid));
1909 if (inf->vfork_child != NULL)
1911 if (debug_linux_nat)
1912 fprintf_unfiltered (gdb_stdlog,
1913 "RC: Not resuming %s (vfork parent)\n",
1914 target_pid_to_str (lp->ptid));
1916 else if (lp->status == 0
1917 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
1919 if (debug_linux_nat)
1920 fprintf_unfiltered (gdb_stdlog,
1921 "RC: PTRACE_CONT %s, 0, 0 (resuming sibling)\n",
1922 target_pid_to_str (lp->ptid));
1924 if (linux_nat_prepare_to_resume != NULL)
1925 linux_nat_prepare_to_resume (lp);
1926 linux_ops->to_resume (linux_ops,
1927 pid_to_ptid (GET_LWP (lp->ptid)),
1928 step, TARGET_SIGNAL_0);
1931 memset (&lp->siginfo, 0, sizeof (lp->siginfo));
1932 lp->stopped_by_watchpoint = 0;
1936 if (debug_linux_nat)
1937 fprintf_unfiltered (gdb_stdlog,
1938 "RC: Not resuming sibling %s (has pending)\n",
1939 target_pid_to_str (lp->ptid));
1944 if (debug_linux_nat)
1945 fprintf_unfiltered (gdb_stdlog,
1946 "RC: Not resuming sibling %s (not stopped)\n",
1947 target_pid_to_str (lp->ptid));
1952 resume_callback (struct lwp_info *lp, void *data)
1959 resume_clear_callback (struct lwp_info *lp, void *data)
1962 lp->last_resume_kind = resume_stop;
1967 resume_set_callback (struct lwp_info *lp, void *data)
1970 lp->last_resume_kind = resume_continue;
1975 linux_nat_resume (struct target_ops *ops,
1976 ptid_t ptid, int step, enum target_signal signo)
1979 struct lwp_info *lp;
1982 if (debug_linux_nat)
1983 fprintf_unfiltered (gdb_stdlog,
1984 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1985 step ? "step" : "resume",
1986 target_pid_to_str (ptid),
1987 (signo != TARGET_SIGNAL_0
1988 ? strsignal (target_signal_to_host (signo)) : "0"),
1989 target_pid_to_str (inferior_ptid));
1991 block_child_signals (&prev_mask);
1993 /* A specific PTID means `step only this process id'. */
1994 resume_many = (ptid_equal (minus_one_ptid, ptid)
1995 || ptid_is_pid (ptid));
1997 /* Mark the lwps we're resuming as resumed. */
1998 iterate_over_lwps (ptid, resume_set_callback, NULL);
2000 /* See if it's the current inferior that should be handled
2003 lp = find_lwp_pid (inferior_ptid);
2005 lp = find_lwp_pid (ptid);
2006 gdb_assert (lp != NULL);
2008 /* Remember if we're stepping. */
2010 lp->last_resume_kind = step ? resume_step : resume_continue;
2012 /* If we have a pending wait status for this thread, there is no
2013 point in resuming the process. But first make sure that
2014 linux_nat_wait won't preemptively handle the event - we
2015 should never take this short-circuit if we are going to
2016 leave LP running, since we have skipped resuming all the
2017 other threads. This bit of code needs to be synchronized
2018 with linux_nat_wait. */
2020 if (lp->status && WIFSTOPPED (lp->status))
2023 && WSTOPSIG (lp->status)
2024 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
2026 if (debug_linux_nat)
2027 fprintf_unfiltered (gdb_stdlog,
2028 "LLR: Not short circuiting for ignored "
2029 "status 0x%x\n", lp->status);
2031 /* FIXME: What should we do if we are supposed to continue
2032 this thread with a signal? */
2033 gdb_assert (signo == TARGET_SIGNAL_0);
2034 signo = target_signal_from_host (WSTOPSIG (lp->status));
2039 if (lp->status || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2041 /* FIXME: What should we do if we are supposed to continue
2042 this thread with a signal? */
2043 gdb_assert (signo == TARGET_SIGNAL_0);
2045 if (debug_linux_nat)
2046 fprintf_unfiltered (gdb_stdlog,
2047 "LLR: Short circuiting for status 0x%x\n",
2050 restore_child_signals_mask (&prev_mask);
2051 if (target_can_async_p ())
2053 target_async (inferior_event_handler, 0);
2054 /* Tell the event loop we have something to process. */
2060 /* Mark LWP as not stopped to prevent it from being continued by
2065 iterate_over_lwps (ptid, resume_callback, NULL);
2067 /* Convert to something the lower layer understands. */
2068 ptid = pid_to_ptid (GET_LWP (lp->ptid));
2070 if (linux_nat_prepare_to_resume != NULL)
2071 linux_nat_prepare_to_resume (lp);
2072 linux_ops->to_resume (linux_ops, ptid, step, signo);
2073 memset (&lp->siginfo, 0, sizeof (lp->siginfo));
2074 lp->stopped_by_watchpoint = 0;
2076 if (debug_linux_nat)
2077 fprintf_unfiltered (gdb_stdlog,
2078 "LLR: %s %s, %s (resume event thread)\n",
2079 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
2080 target_pid_to_str (ptid),
2081 (signo != TARGET_SIGNAL_0
2082 ? strsignal (target_signal_to_host (signo)) : "0"));
2084 restore_child_signals_mask (&prev_mask);
2085 if (target_can_async_p ())
2086 target_async (inferior_event_handler, 0);
2089 /* Send a signal to an LWP. */
2092 kill_lwp (int lwpid, int signo)
2094 /* Use tkill, if possible, in case we are using nptl threads. If tkill
2095 fails, then we are not using nptl threads and we should be using kill. */
2097 #ifdef HAVE_TKILL_SYSCALL
2099 static int tkill_failed;
2106 ret = syscall (__NR_tkill, lwpid, signo);
2107 if (errno != ENOSYS)
2114 return kill (lwpid, signo);
2117 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
2118 event, check if the core is interested in it: if not, ignore the
2119 event, and keep waiting; otherwise, we need to toggle the LWP's
2120 syscall entry/exit status, since the ptrace event itself doesn't
2121 indicate it, and report the trap to higher layers. */
2124 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
2126 struct target_waitstatus *ourstatus = &lp->waitstatus;
2127 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
2128 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
2132 /* If we're stopping threads, there's a SIGSTOP pending, which
2133 makes it so that the LWP reports an immediate syscall return,
2134 followed by the SIGSTOP. Skip seeing that "return" using
2135 PTRACE_CONT directly, and let stop_wait_callback collect the
2136 SIGSTOP. Later when the thread is resumed, a new syscall
2137 entry event. If we didn't do this (and returned 0), we'd
2138 leave a syscall entry pending, and our caller, by using
2139 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
2140 itself. Later, when the user re-resumes this LWP, we'd see
2141 another syscall entry event and we'd mistake it for a return.
2143 If stop_wait_callback didn't force the SIGSTOP out of the LWP
2144 (leaving immediately with LWP->signalled set, without issuing
2145 a PTRACE_CONT), it would still be problematic to leave this
2146 syscall enter pending, as later when the thread is resumed,
2147 it would then see the same syscall exit mentioned above,
2148 followed by the delayed SIGSTOP, while the syscall didn't
2149 actually get to execute. It seems it would be even more
2150 confusing to the user. */
2152 if (debug_linux_nat)
2153 fprintf_unfiltered (gdb_stdlog,
2154 "LHST: ignoring syscall %d "
2155 "for LWP %ld (stopping threads), "
2156 "resuming with PTRACE_CONT for SIGSTOP\n",
2158 GET_LWP (lp->ptid));
2160 lp->syscall_state = TARGET_WAITKIND_IGNORE;
2161 ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
2165 if (catch_syscall_enabled ())
2167 /* Always update the entry/return state, even if this particular
2168 syscall isn't interesting to the core now. In async mode,
2169 the user could install a new catchpoint for this syscall
2170 between syscall enter/return, and we'll need to know to
2171 report a syscall return if that happens. */
2172 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
2173 ? TARGET_WAITKIND_SYSCALL_RETURN
2174 : TARGET_WAITKIND_SYSCALL_ENTRY);
2176 if (catching_syscall_number (syscall_number))
2178 /* Alright, an event to report. */
2179 ourstatus->kind = lp->syscall_state;
2180 ourstatus->value.syscall_number = syscall_number;
2182 if (debug_linux_nat)
2183 fprintf_unfiltered (gdb_stdlog,
2184 "LHST: stopping for %s of syscall %d"
2187 == TARGET_WAITKIND_SYSCALL_ENTRY
2188 ? "entry" : "return",
2190 GET_LWP (lp->ptid));
2194 if (debug_linux_nat)
2195 fprintf_unfiltered (gdb_stdlog,
2196 "LHST: ignoring %s of syscall %d "
2198 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
2199 ? "entry" : "return",
2201 GET_LWP (lp->ptid));
2205 /* If we had been syscall tracing, and hence used PT_SYSCALL
2206 before on this LWP, it could happen that the user removes all
2207 syscall catchpoints before we get to process this event.
2208 There are two noteworthy issues here:
2210 - When stopped at a syscall entry event, resuming with
2211 PT_STEP still resumes executing the syscall and reports a
2214 - Only PT_SYSCALL catches syscall enters. If we last
2215 single-stepped this thread, then this event can't be a
2216 syscall enter. If we last single-stepped this thread, this
2217 has to be a syscall exit.
2219 The points above mean that the next resume, be it PT_STEP or
2220 PT_CONTINUE, can not trigger a syscall trace event. */
2221 if (debug_linux_nat)
2222 fprintf_unfiltered (gdb_stdlog,
2223 "LHST: caught syscall event "
2224 "with no syscall catchpoints."
2225 " %d for LWP %ld, ignoring\n",
2227 GET_LWP (lp->ptid));
2228 lp->syscall_state = TARGET_WAITKIND_IGNORE;
2231 /* The core isn't interested in this event. For efficiency, avoid
2232 stopping all threads only to have the core resume them all again.
2233 Since we're not stopping threads, if we're still syscall tracing
2234 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
2235 subsequent syscall. Simply resume using the inf-ptrace layer,
2236 which knows when to use PT_SYSCALL or PT_CONTINUE. */
2238 /* Note that gdbarch_get_syscall_number may access registers, hence
2240 registers_changed ();
2241 if (linux_nat_prepare_to_resume != NULL)
2242 linux_nat_prepare_to_resume (lp);
2243 linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
2244 lp->step, TARGET_SIGNAL_0);
2248 /* Handle a GNU/Linux extended wait response. If we see a clone
2249 event, we need to add the new LWP to our list (and not report the
2250 trap to higher layers). This function returns non-zero if the
2251 event should be ignored and we should wait again. If STOPPING is
2252 true, the new LWP remains stopped, otherwise it is continued. */
2255 linux_handle_extended_wait (struct lwp_info *lp, int status,
2258 int pid = GET_LWP (lp->ptid);
2259 struct target_waitstatus *ourstatus = &lp->waitstatus;
2260 int event = status >> 16;
2262 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
2263 || event == PTRACE_EVENT_CLONE)
2265 unsigned long new_pid;
2268 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
2270 /* If we haven't already seen the new PID stop, wait for it now. */
2271 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
2273 /* The new child has a pending SIGSTOP. We can't affect it until it
2274 hits the SIGSTOP, but we're already attached. */
2275 ret = my_waitpid (new_pid, &status,
2276 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
2278 perror_with_name (_("waiting for new child"));
2279 else if (ret != new_pid)
2280 internal_error (__FILE__, __LINE__,
2281 _("wait returned unexpected PID %d"), ret);
2282 else if (!WIFSTOPPED (status))
2283 internal_error (__FILE__, __LINE__,
2284 _("wait returned unexpected status 0x%x"), status);
2287 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
2289 if (event == PTRACE_EVENT_FORK
2290 && linux_fork_checkpointing_p (GET_PID (lp->ptid)))
2292 /* Handle checkpointing by linux-fork.c here as a special
2293 case. We don't want the follow-fork-mode or 'catch fork'
2294 to interfere with this. */
2296 /* This won't actually modify the breakpoint list, but will
2297 physically remove the breakpoints from the child. */
2298 detach_breakpoints (new_pid);
2300 /* Retain child fork in ptrace (stopped) state. */
2301 if (!find_fork_pid (new_pid))
2304 /* Report as spurious, so that infrun doesn't want to follow
2305 this fork. We're actually doing an infcall in
2307 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
2308 linux_enable_event_reporting (pid_to_ptid (new_pid));
2310 /* Report the stop to the core. */
2314 if (event == PTRACE_EVENT_FORK)
2315 ourstatus->kind = TARGET_WAITKIND_FORKED;
2316 else if (event == PTRACE_EVENT_VFORK)
2317 ourstatus->kind = TARGET_WAITKIND_VFORKED;
2320 struct lwp_info *new_lp;
2322 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2324 if (debug_linux_nat)
2325 fprintf_unfiltered (gdb_stdlog,
2326 "LHEW: Got clone event "
2327 "from LWP %d, new child is LWP %ld\n",
2330 new_lp = add_lwp (BUILD_LWP (new_pid, GET_PID (lp->ptid)));
2332 new_lp->stopped = 1;
2334 if (WSTOPSIG (status) != SIGSTOP)
2336 /* This can happen if someone starts sending signals to
2337 the new thread before it gets a chance to run, which
2338 have a lower number than SIGSTOP (e.g. SIGUSR1).
2339 This is an unlikely case, and harder to handle for
2340 fork / vfork than for clone, so we do not try - but
2341 we handle it for clone events here. We'll send
2342 the other signal on to the thread below. */
2344 new_lp->signalled = 1;
2348 struct thread_info *tp;
2350 /* When we stop for an event in some other thread, and
2351 pull the thread list just as this thread has cloned,
2352 we'll have seen the new thread in the thread_db list
2353 before handling the CLONE event (glibc's
2354 pthread_create adds the new thread to the thread list
2355 before clone'ing, and has the kernel fill in the
2356 thread's tid on the clone call with
2357 CLONE_PARENT_SETTID). If that happened, and the core
2358 had requested the new thread to stop, we'll have
2359 killed it with SIGSTOP. But since SIGSTOP is not an
2360 RT signal, it can only be queued once. We need to be
2361 careful to not resume the LWP if we wanted it to
2362 stop. In that case, we'll leave the SIGSTOP pending.
2363 It will later be reported as TARGET_SIGNAL_0. */
2364 tp = find_thread_ptid (new_lp->ptid);
2365 if (tp != NULL && tp->stop_requested)
2366 new_lp->last_resume_kind = resume_stop;
2373 /* Add the new thread to GDB's lists as soon as possible
2376 1) the frontend doesn't have to wait for a stop to
2379 2) we tag it with the correct running state. */
2381 /* If the thread_db layer is active, let it know about
2382 this new thread, and add it to GDB's list. */
2383 if (!thread_db_attach_lwp (new_lp->ptid))
2385 /* We're not using thread_db. Add it to GDB's
2387 target_post_attach (GET_LWP (new_lp->ptid));
2388 add_thread (new_lp->ptid);
2393 set_running (new_lp->ptid, 1);
2394 set_executing (new_lp->ptid, 1);
2395 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2397 new_lp->last_resume_kind = resume_continue;
2403 /* We created NEW_LP so it cannot yet contain STATUS. */
2404 gdb_assert (new_lp->status == 0);
2406 /* Save the wait status to report later. */
2407 if (debug_linux_nat)
2408 fprintf_unfiltered (gdb_stdlog,
2409 "LHEW: waitpid of new LWP %ld, "
2410 "saving status %s\n",
2411 (long) GET_LWP (new_lp->ptid),
2412 status_to_str (status));
2413 new_lp->status = status;
2416 /* Note the need to use the low target ops to resume, to
2417 handle resuming with PT_SYSCALL if we have syscall
2421 new_lp->resumed = 1;
2425 gdb_assert (new_lp->last_resume_kind == resume_continue);
2426 if (debug_linux_nat)
2427 fprintf_unfiltered (gdb_stdlog,
2428 "LHEW: resuming new LWP %ld\n",
2429 GET_LWP (new_lp->ptid));
2430 if (linux_nat_prepare_to_resume != NULL)
2431 linux_nat_prepare_to_resume (new_lp);
2432 linux_ops->to_resume (linux_ops, pid_to_ptid (new_pid),
2433 0, TARGET_SIGNAL_0);
2434 new_lp->stopped = 0;
2438 if (debug_linux_nat)
2439 fprintf_unfiltered (gdb_stdlog,
2440 "LHEW: resuming parent LWP %d\n", pid);
2441 if (linux_nat_prepare_to_resume != NULL)
2442 linux_nat_prepare_to_resume (lp);
2443 linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
2444 0, TARGET_SIGNAL_0);
2452 if (event == PTRACE_EVENT_EXEC)
2454 if (debug_linux_nat)
2455 fprintf_unfiltered (gdb_stdlog,
2456 "LHEW: Got exec event from LWP %ld\n",
2457 GET_LWP (lp->ptid));
2459 ourstatus->kind = TARGET_WAITKIND_EXECD;
2460 ourstatus->value.execd_pathname
2461 = xstrdup (linux_child_pid_to_exec_file (pid));
2466 if (event == PTRACE_EVENT_VFORK_DONE)
2468 if (current_inferior ()->waiting_for_vfork_done)
2470 if (debug_linux_nat)
2471 fprintf_unfiltered (gdb_stdlog,
2472 "LHEW: Got expected PTRACE_EVENT_"
2473 "VFORK_DONE from LWP %ld: stopping\n",
2474 GET_LWP (lp->ptid));
2476 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2480 if (debug_linux_nat)
2481 fprintf_unfiltered (gdb_stdlog,
2482 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2483 "from LWP %ld: resuming\n",
2484 GET_LWP (lp->ptid));
2485 ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
2489 internal_error (__FILE__, __LINE__,
2490 _("unknown ptrace event %d"), event);
2493 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2497 wait_lwp (struct lwp_info *lp)
2501 int thread_dead = 0;
2504 gdb_assert (!lp->stopped);
2505 gdb_assert (lp->status == 0);
2507 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2508 block_child_signals (&prev_mask);
2512 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2513 was right and we should just call sigsuspend. */
2515 pid = my_waitpid (GET_LWP (lp->ptid), &status, WNOHANG);
2516 if (pid == -1 && errno == ECHILD)
2517 pid = my_waitpid (GET_LWP (lp->ptid), &status, __WCLONE | WNOHANG);
2518 if (pid == -1 && errno == ECHILD)
2520 /* The thread has previously exited. We need to delete it
2521 now because, for some vendor 2.4 kernels with NPTL
2522 support backported, there won't be an exit event unless
2523 it is the main thread. 2.6 kernels will report an exit
2524 event for each thread that exits, as expected. */
2526 if (debug_linux_nat)
2527 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2528 target_pid_to_str (lp->ptid));
2533 /* Bugs 10970, 12702.
2534 Thread group leader may have exited in which case we'll lock up in
2535 waitpid if there are other threads, even if they are all zombies too.
2536 Basically, we're not supposed to use waitpid this way.
2537 __WCLONE is not applicable for the leader so we can't use that.
2538 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2539 process; it gets ESRCH both for the zombie and for running processes.
2541 As a workaround, check if we're waiting for the thread group leader and
2542 if it's a zombie, and avoid calling waitpid if it is.
2544 This is racy, what if the tgl becomes a zombie right after we check?
2545 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2546 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2548 if (GET_PID (lp->ptid) == GET_LWP (lp->ptid)
2549 && linux_proc_pid_is_zombie (GET_LWP (lp->ptid)))
2552 if (debug_linux_nat)
2553 fprintf_unfiltered (gdb_stdlog,
2554 "WL: Thread group leader %s vanished.\n",
2555 target_pid_to_str (lp->ptid));
2559 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2560 get invoked despite our caller had them intentionally blocked by
2561 block_child_signals. This is sensitive only to the loop of
2562 linux_nat_wait_1 and there if we get called my_waitpid gets called
2563 again before it gets to sigsuspend so we can safely let the handlers
2564 get executed here. */
2566 sigsuspend (&suspend_mask);
2569 restore_child_signals_mask (&prev_mask);
2573 gdb_assert (pid == GET_LWP (lp->ptid));
2575 if (debug_linux_nat)
2577 fprintf_unfiltered (gdb_stdlog,
2578 "WL: waitpid %s received %s\n",
2579 target_pid_to_str (lp->ptid),
2580 status_to_str (status));
2583 /* Check if the thread has exited. */
2584 if (WIFEXITED (status) || WIFSIGNALED (status))
2587 if (debug_linux_nat)
2588 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2589 target_pid_to_str (lp->ptid));
2599 gdb_assert (WIFSTOPPED (status));
2601 /* Handle GNU/Linux's syscall SIGTRAPs. */
2602 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2604 /* No longer need the sysgood bit. The ptrace event ends up
2605 recorded in lp->waitstatus if we care for it. We can carry
2606 on handling the event like a regular SIGTRAP from here
2608 status = W_STOPCODE (SIGTRAP);
2609 if (linux_handle_syscall_trap (lp, 1))
2610 return wait_lwp (lp);
2613 /* Handle GNU/Linux's extended waitstatus for trace events. */
2614 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2616 if (debug_linux_nat)
2617 fprintf_unfiltered (gdb_stdlog,
2618 "WL: Handling extended status 0x%06x\n",
2620 if (linux_handle_extended_wait (lp, status, 1))
2621 return wait_lwp (lp);
2627 /* Save the most recent siginfo for LP. This is currently only called
2628 for SIGTRAP; some ports use the si_addr field for
2629 target_stopped_data_address. In the future, it may also be used to
2630 restore the siginfo of requeued signals. */
2633 save_siginfo (struct lwp_info *lp)
2636 ptrace (PTRACE_GETSIGINFO, GET_LWP (lp->ptid),
2637 (PTRACE_TYPE_ARG3) 0, &lp->siginfo);
2640 memset (&lp->siginfo, 0, sizeof (lp->siginfo));
2643 /* Send a SIGSTOP to LP. */
2646 stop_callback (struct lwp_info *lp, void *data)
2648 if (!lp->stopped && !lp->signalled)
2652 if (debug_linux_nat)
2654 fprintf_unfiltered (gdb_stdlog,
2655 "SC: kill %s **<SIGSTOP>**\n",
2656 target_pid_to_str (lp->ptid));
2659 ret = kill_lwp (GET_LWP (lp->ptid), SIGSTOP);
2660 if (debug_linux_nat)
2662 fprintf_unfiltered (gdb_stdlog,
2663 "SC: lwp kill %d %s\n",
2665 errno ? safe_strerror (errno) : "ERRNO-OK");
2669 gdb_assert (lp->status == 0);
2675 /* Request a stop on LWP. */
2678 linux_stop_lwp (struct lwp_info *lwp)
2680 stop_callback (lwp, NULL);
2683 /* Return non-zero if LWP PID has a pending SIGINT. */
2686 linux_nat_has_pending_sigint (int pid)
2688 sigset_t pending, blocked, ignored;
2690 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2692 if (sigismember (&pending, SIGINT)
2693 && !sigismember (&ignored, SIGINT))
2699 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2702 set_ignore_sigint (struct lwp_info *lp, void *data)
2704 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2705 flag to consume the next one. */
2706 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2707 && WSTOPSIG (lp->status) == SIGINT)
2710 lp->ignore_sigint = 1;
2715 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2716 This function is called after we know the LWP has stopped; if the LWP
2717 stopped before the expected SIGINT was delivered, then it will never have
2718 arrived. Also, if the signal was delivered to a shared queue and consumed
2719 by a different thread, it will never be delivered to this LWP. */
2722 maybe_clear_ignore_sigint (struct lwp_info *lp)
2724 if (!lp->ignore_sigint)
2727 if (!linux_nat_has_pending_sigint (GET_LWP (lp->ptid)))
2729 if (debug_linux_nat)
2730 fprintf_unfiltered (gdb_stdlog,
2731 "MCIS: Clearing bogus flag for %s\n",
2732 target_pid_to_str (lp->ptid));
2733 lp->ignore_sigint = 0;
2737 /* Fetch the possible triggered data watchpoint info and store it in
2740 On some archs, like x86, that use debug registers to set
2741 watchpoints, it's possible that the way to know which watched
2742 address trapped, is to check the register that is used to select
2743 which address to watch. Problem is, between setting the watchpoint
2744 and reading back which data address trapped, the user may change
2745 the set of watchpoints, and, as a consequence, GDB changes the
2746 debug registers in the inferior. To avoid reading back a stale
2747 stopped-data-address when that happens, we cache in LP the fact
2748 that a watchpoint trapped, and the corresponding data address, as
2749 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2750 registers meanwhile, we have the cached data we can rely on. */
2753 save_sigtrap (struct lwp_info *lp)
2755 struct cleanup *old_chain;
2757 if (linux_ops->to_stopped_by_watchpoint == NULL)
2759 lp->stopped_by_watchpoint = 0;
2763 old_chain = save_inferior_ptid ();
2764 inferior_ptid = lp->ptid;
2766 lp->stopped_by_watchpoint = linux_ops->to_stopped_by_watchpoint ();
2768 if (lp->stopped_by_watchpoint)
2770 if (linux_ops->to_stopped_data_address != NULL)
2771 lp->stopped_data_address_p =
2772 linux_ops->to_stopped_data_address (¤t_target,
2773 &lp->stopped_data_address);
2775 lp->stopped_data_address_p = 0;
2778 do_cleanups (old_chain);
2781 /* See save_sigtrap. */
2784 linux_nat_stopped_by_watchpoint (void)
2786 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2788 gdb_assert (lp != NULL);
2790 return lp->stopped_by_watchpoint;
2794 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2796 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2798 gdb_assert (lp != NULL);
2800 *addr_p = lp->stopped_data_address;
2802 return lp->stopped_data_address_p;
2805 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2808 sigtrap_is_event (int status)
2810 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2813 /* SIGTRAP-like events recognizer. */
2815 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
2817 /* Check for SIGTRAP-like events in LP. */
2820 linux_nat_lp_status_is_event (struct lwp_info *lp)
2822 /* We check for lp->waitstatus in addition to lp->status, because we can
2823 have pending process exits recorded in lp->status
2824 and W_EXITCODE(0,0) == 0. We should probably have an additional
2825 lp->status_p flag. */
2827 return (lp->waitstatus.kind == TARGET_WAITKIND_IGNORE
2828 && linux_nat_status_is_event (lp->status));
2831 /* Set alternative SIGTRAP-like events recognizer. If
2832 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2836 linux_nat_set_status_is_event (struct target_ops *t,
2837 int (*status_is_event) (int status))
2839 linux_nat_status_is_event = status_is_event;
2842 /* Wait until LP is stopped. */
2845 stop_wait_callback (struct lwp_info *lp, void *data)
2847 struct inferior *inf = find_inferior_pid (GET_PID (lp->ptid));
2849 /* If this is a vfork parent, bail out, it is not going to report
2850 any SIGSTOP until the vfork is done with. */
2851 if (inf->vfork_child != NULL)
2858 status = wait_lwp (lp);
2862 if (lp->ignore_sigint && WIFSTOPPED (status)
2863 && WSTOPSIG (status) == SIGINT)
2865 lp->ignore_sigint = 0;
2868 ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
2869 if (debug_linux_nat)
2870 fprintf_unfiltered (gdb_stdlog,
2871 "PTRACE_CONT %s, 0, 0 (%s) "
2872 "(discarding SIGINT)\n",
2873 target_pid_to_str (lp->ptid),
2874 errno ? safe_strerror (errno) : "OK");
2876 return stop_wait_callback (lp, NULL);
2879 maybe_clear_ignore_sigint (lp);
2881 if (WSTOPSIG (status) != SIGSTOP)
2883 if (linux_nat_status_is_event (status))
2885 /* If a LWP other than the LWP that we're reporting an
2886 event for has hit a GDB breakpoint (as opposed to
2887 some random trap signal), then just arrange for it to
2888 hit it again later. We don't keep the SIGTRAP status
2889 and don't forward the SIGTRAP signal to the LWP. We
2890 will handle the current event, eventually we will
2891 resume all LWPs, and this one will get its breakpoint
2894 If we do not do this, then we run the risk that the
2895 user will delete or disable the breakpoint, but the
2896 thread will have already tripped on it. */
2898 /* Save the trap's siginfo in case we need it later. */
2903 /* Now resume this LWP and get the SIGSTOP event. */
2905 ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
2906 if (debug_linux_nat)
2908 fprintf_unfiltered (gdb_stdlog,
2909 "PTRACE_CONT %s, 0, 0 (%s)\n",
2910 target_pid_to_str (lp->ptid),
2911 errno ? safe_strerror (errno) : "OK");
2913 fprintf_unfiltered (gdb_stdlog,
2914 "SWC: Candidate SIGTRAP event in %s\n",
2915 target_pid_to_str (lp->ptid));
2917 /* Hold this event/waitstatus while we check to see if
2918 there are any more (we still want to get that SIGSTOP). */
2919 stop_wait_callback (lp, NULL);
2921 /* Hold the SIGTRAP for handling by linux_nat_wait. If
2922 there's another event, throw it back into the
2926 if (debug_linux_nat)
2927 fprintf_unfiltered (gdb_stdlog,
2928 "SWC: kill %s, %s\n",
2929 target_pid_to_str (lp->ptid),
2930 status_to_str ((int) status));
2931 kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (lp->status));
2934 /* Save the sigtrap event. */
2935 lp->status = status;
2940 /* The thread was stopped with a signal other than
2941 SIGSTOP, and didn't accidentally trip a breakpoint. */
2943 if (debug_linux_nat)
2945 fprintf_unfiltered (gdb_stdlog,
2946 "SWC: Pending event %s in %s\n",
2947 status_to_str ((int) status),
2948 target_pid_to_str (lp->ptid));
2950 /* Now resume this LWP and get the SIGSTOP event. */
2952 ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
2953 if (debug_linux_nat)
2954 fprintf_unfiltered (gdb_stdlog,
2955 "SWC: PTRACE_CONT %s, 0, 0 (%s)\n",
2956 target_pid_to_str (lp->ptid),
2957 errno ? safe_strerror (errno) : "OK");
2959 /* Hold this event/waitstatus while we check to see if
2960 there are any more (we still want to get that SIGSTOP). */
2961 stop_wait_callback (lp, NULL);
2963 /* If the lp->status field is still empty, use it to
2964 hold this event. If not, then this event must be
2965 returned to the event queue of the LWP. */
2968 if (debug_linux_nat)
2970 fprintf_unfiltered (gdb_stdlog,
2971 "SWC: kill %s, %s\n",
2972 target_pid_to_str (lp->ptid),
2973 status_to_str ((int) status));
2975 kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (status));
2978 lp->status = status;
2984 /* We caught the SIGSTOP that we intended to catch, so
2985 there's no SIGSTOP pending. */
2994 /* Return non-zero if LP has a wait status pending. */
2997 status_callback (struct lwp_info *lp, void *data)
2999 /* Only report a pending wait status if we pretend that this has
3000 indeed been resumed. */
3004 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3006 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
3007 or a pending process exit. Note that `W_EXITCODE(0,0) ==
3008 0', so a clean process exit can not be stored pending in
3009 lp->status, it is indistinguishable from
3010 no-pending-status. */
3014 if (lp->status != 0)
3020 /* Return non-zero if LP isn't stopped. */
3023 running_callback (struct lwp_info *lp, void *data)
3025 return (!lp->stopped
3026 || ((lp->status != 0
3027 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3031 /* Count the LWP's that have had events. */
3034 count_events_callback (struct lwp_info *lp, void *data)
3038 gdb_assert (count != NULL);
3040 /* Count only resumed LWPs that have a SIGTRAP event pending. */
3041 if (lp->resumed && linux_nat_lp_status_is_event (lp))
3047 /* Select the LWP (if any) that is currently being single-stepped. */
3050 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
3052 if (lp->last_resume_kind == resume_step
3059 /* Select the Nth LWP that has had a SIGTRAP event. */
3062 select_event_lwp_callback (struct lwp_info *lp, void *data)
3064 int *selector = data;
3066 gdb_assert (selector != NULL);
3068 /* Select only resumed LWPs that have a SIGTRAP event pending. */
3069 if (lp->resumed && linux_nat_lp_status_is_event (lp))
3070 if ((*selector)-- == 0)
3077 cancel_breakpoint (struct lwp_info *lp)
3079 /* Arrange for a breakpoint to be hit again later. We don't keep
3080 the SIGTRAP status and don't forward the SIGTRAP signal to the
3081 LWP. We will handle the current event, eventually we will resume
3082 this LWP, and this breakpoint will trap again.
3084 If we do not do this, then we run the risk that the user will
3085 delete or disable the breakpoint, but the LWP will have already
3088 struct regcache *regcache = get_thread_regcache (lp->ptid);
3089 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3092 pc = regcache_read_pc (regcache) - gdbarch_decr_pc_after_break (gdbarch);
3093 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3095 if (debug_linux_nat)
3096 fprintf_unfiltered (gdb_stdlog,
3097 "CB: Push back breakpoint for %s\n",
3098 target_pid_to_str (lp->ptid));
3100 /* Back up the PC if necessary. */
3101 if (gdbarch_decr_pc_after_break (gdbarch))
3102 regcache_write_pc (regcache, pc);
3110 cancel_breakpoints_callback (struct lwp_info *lp, void *data)
3112 struct lwp_info *event_lp = data;
3114 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
3118 /* If a LWP other than the LWP that we're reporting an event for has
3119 hit a GDB breakpoint (as opposed to some random trap signal),
3120 then just arrange for it to hit it again later. We don't keep
3121 the SIGTRAP status and don't forward the SIGTRAP signal to the
3122 LWP. We will handle the current event, eventually we will resume
3123 all LWPs, and this one will get its breakpoint trap again.
3125 If we do not do this, then we run the risk that the user will
3126 delete or disable the breakpoint, but the LWP will have already
3129 if (linux_nat_lp_status_is_event (lp)
3130 && cancel_breakpoint (lp))
3131 /* Throw away the SIGTRAP. */
3137 /* Select one LWP out of those that have events pending. */
3140 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
3143 int random_selector;
3144 struct lwp_info *event_lp;
3146 /* Record the wait status for the original LWP. */
3147 (*orig_lp)->status = *status;
3149 /* Give preference to any LWP that is being single-stepped. */
3150 event_lp = iterate_over_lwps (filter,
3151 select_singlestep_lwp_callback, NULL);
3152 if (event_lp != NULL)
3154 if (debug_linux_nat)
3155 fprintf_unfiltered (gdb_stdlog,
3156 "SEL: Select single-step %s\n",
3157 target_pid_to_str (event_lp->ptid));
3161 /* No single-stepping LWP. Select one at random, out of those
3162 which have had SIGTRAP events. */
3164 /* First see how many SIGTRAP events we have. */
3165 iterate_over_lwps (filter, count_events_callback, &num_events);
3167 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
3168 random_selector = (int)
3169 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
3171 if (debug_linux_nat && num_events > 1)
3172 fprintf_unfiltered (gdb_stdlog,
3173 "SEL: Found %d SIGTRAP events, selecting #%d\n",
3174 num_events, random_selector);
3176 event_lp = iterate_over_lwps (filter,
3177 select_event_lwp_callback,
3181 if (event_lp != NULL)
3183 /* Switch the event LWP. */
3184 *orig_lp = event_lp;
3185 *status = event_lp->status;
3188 /* Flush the wait status for the event LWP. */
3189 (*orig_lp)->status = 0;
3192 /* Return non-zero if LP has been resumed. */
3195 resumed_callback (struct lwp_info *lp, void *data)
3200 /* Stop an active thread, verify it still exists, then resume it. If
3201 the thread ends up with a pending status, then it is not resumed,
3202 and *DATA (really a pointer to int), is set. */
3205 stop_and_resume_callback (struct lwp_info *lp, void *data)
3207 int *new_pending_p = data;
3211 ptid_t ptid = lp->ptid;
3213 stop_callback (lp, NULL);
3214 stop_wait_callback (lp, NULL);
3216 /* Resume if the lwp still exists, and the core wanted it
3218 lp = find_lwp_pid (ptid);
3221 if (lp->last_resume_kind == resume_stop
3224 /* The core wanted the LWP to stop. Even if it stopped
3225 cleanly (with SIGSTOP), leave the event pending. */
3226 if (debug_linux_nat)
3227 fprintf_unfiltered (gdb_stdlog,
3228 "SARC: core wanted LWP %ld stopped "
3229 "(leaving SIGSTOP pending)\n",
3230 GET_LWP (lp->ptid));
3231 lp->status = W_STOPCODE (SIGSTOP);
3234 if (lp->status == 0)
3236 if (debug_linux_nat)
3237 fprintf_unfiltered (gdb_stdlog,
3238 "SARC: re-resuming LWP %ld\n",
3239 GET_LWP (lp->ptid));
3240 resume_lwp (lp, lp->step);
3244 if (debug_linux_nat)
3245 fprintf_unfiltered (gdb_stdlog,
3246 "SARC: not re-resuming LWP %ld "
3248 GET_LWP (lp->ptid));
3257 /* Check if we should go on and pass this event to common code.
3258 Return the affected lwp if we are, or NULL otherwise. If we stop
3259 all lwps temporarily, we may end up with new pending events in some
3260 other lwp. In that case set *NEW_PENDING_P to true. */
3262 static struct lwp_info *
3263 linux_nat_filter_event (int lwpid, int status, int *new_pending_p)
3265 struct lwp_info *lp;
3269 lp = find_lwp_pid (pid_to_ptid (lwpid));
3271 /* Check for stop events reported by a process we didn't already
3272 know about - anything not already in our LWP list.
3274 If we're expecting to receive stopped processes after
3275 fork, vfork, and clone events, then we'll just add the
3276 new one to our list and go back to waiting for the event
3277 to be reported - the stopped process might be returned
3278 from waitpid before or after the event is.
3280 But note the case of a non-leader thread exec'ing after the
3281 leader having exited, and gone from our lists. The non-leader
3282 thread changes its tid to the tgid. */
3284 if (WIFSTOPPED (status) && lp == NULL
3285 && (WSTOPSIG (status) == SIGTRAP && status >> 16 == PTRACE_EVENT_EXEC))
3287 /* A multi-thread exec after we had seen the leader exiting. */
3288 if (debug_linux_nat)
3289 fprintf_unfiltered (gdb_stdlog,
3290 "LLW: Re-adding thread group leader LWP %d.\n",
3293 lp = add_lwp (BUILD_LWP (lwpid, lwpid));
3296 add_thread (lp->ptid);
3299 if (WIFSTOPPED (status) && !lp)
3301 add_to_pid_list (&stopped_pids, lwpid, status);
3305 /* Make sure we don't report an event for the exit of an LWP not in
3306 our list, i.e. not part of the current process. This can happen
3307 if we detach from a program we originally forked and then it
3309 if (!WIFSTOPPED (status) && !lp)
3312 /* Handle GNU/Linux's syscall SIGTRAPs. */
3313 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
3315 /* No longer need the sysgood bit. The ptrace event ends up
3316 recorded in lp->waitstatus if we care for it. We can carry
3317 on handling the event like a regular SIGTRAP from here
3319 status = W_STOPCODE (SIGTRAP);
3320 if (linux_handle_syscall_trap (lp, 0))
3324 /* Handle GNU/Linux's extended waitstatus for trace events. */
3325 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
3327 if (debug_linux_nat)
3328 fprintf_unfiltered (gdb_stdlog,
3329 "LLW: Handling extended status 0x%06x\n",
3331 if (linux_handle_extended_wait (lp, status, 0))
3335 if (linux_nat_status_is_event (status))
3337 /* Save the trap's siginfo in case we need it later. */
3343 /* Check if the thread has exited. */
3344 if ((WIFEXITED (status) || WIFSIGNALED (status))
3345 && num_lwps (GET_PID (lp->ptid)) > 1)
3347 /* If this is the main thread, we must stop all threads and verify
3348 if they are still alive. This is because in the nptl thread model
3349 on Linux 2.4, there is no signal issued for exiting LWPs
3350 other than the main thread. We only get the main thread exit
3351 signal once all child threads have already exited. If we
3352 stop all the threads and use the stop_wait_callback to check
3353 if they have exited we can determine whether this signal
3354 should be ignored or whether it means the end of the debugged
3355 application, regardless of which threading model is being
3357 if (GET_PID (lp->ptid) == GET_LWP (lp->ptid))
3360 iterate_over_lwps (pid_to_ptid (GET_PID (lp->ptid)),
3361 stop_and_resume_callback, new_pending_p);
3364 if (debug_linux_nat)
3365 fprintf_unfiltered (gdb_stdlog,
3366 "LLW: %s exited.\n",
3367 target_pid_to_str (lp->ptid));
3369 if (num_lwps (GET_PID (lp->ptid)) > 1)
3371 /* If there is at least one more LWP, then the exit signal
3372 was not the end of the debugged application and should be
3379 /* Check if the current LWP has previously exited. In the nptl
3380 thread model, LWPs other than the main thread do not issue
3381 signals when they exit so we must check whenever the thread has
3382 stopped. A similar check is made in stop_wait_callback(). */
3383 if (num_lwps (GET_PID (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3385 ptid_t ptid = pid_to_ptid (GET_PID (lp->ptid));
3387 if (debug_linux_nat)
3388 fprintf_unfiltered (gdb_stdlog,
3389 "LLW: %s exited.\n",
3390 target_pid_to_str (lp->ptid));
3394 /* Make sure there is at least one thread running. */
3395 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3397 /* Discard the event. */
3401 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3402 an attempt to stop an LWP. */
3404 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3406 if (debug_linux_nat)
3407 fprintf_unfiltered (gdb_stdlog,
3408 "LLW: Delayed SIGSTOP caught for %s.\n",
3409 target_pid_to_str (lp->ptid));
3413 if (lp->last_resume_kind != resume_stop)
3415 /* This is a delayed SIGSTOP. */
3417 registers_changed ();
3419 if (linux_nat_prepare_to_resume != NULL)
3420 linux_nat_prepare_to_resume (lp);
3421 linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
3422 lp->step, TARGET_SIGNAL_0);
3423 if (debug_linux_nat)
3424 fprintf_unfiltered (gdb_stdlog,
3425 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3427 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3428 target_pid_to_str (lp->ptid));
3431 gdb_assert (lp->resumed);
3433 /* Discard the event. */
3438 /* Make sure we don't report a SIGINT that we have already displayed
3439 for another thread. */
3440 if (lp->ignore_sigint
3441 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3443 if (debug_linux_nat)
3444 fprintf_unfiltered (gdb_stdlog,
3445 "LLW: Delayed SIGINT caught for %s.\n",
3446 target_pid_to_str (lp->ptid));
3448 /* This is a delayed SIGINT. */
3449 lp->ignore_sigint = 0;
3451 registers_changed ();
3452 if (linux_nat_prepare_to_resume != NULL)
3453 linux_nat_prepare_to_resume (lp);
3454 linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
3455 lp->step, TARGET_SIGNAL_0);
3456 if (debug_linux_nat)
3457 fprintf_unfiltered (gdb_stdlog,
3458 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3460 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3461 target_pid_to_str (lp->ptid));
3464 gdb_assert (lp->resumed);
3466 /* Discard the event. */
3470 /* An interesting event. */
3472 lp->status = status;
3476 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3477 their exits until all other threads in the group have exited. */
3480 check_zombie_leaders (void)
3482 struct inferior *inf;
3486 struct lwp_info *leader_lp;
3491 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3492 if (leader_lp != NULL
3493 /* Check if there are other threads in the group, as we may
3494 have raced with the inferior simply exiting. */
3495 && num_lwps (inf->pid) > 1
3496 && linux_proc_pid_is_zombie (inf->pid))
3498 if (debug_linux_nat)
3499 fprintf_unfiltered (gdb_stdlog,
3500 "CZL: Thread group leader %d zombie "
3501 "(it exited, or another thread execd).\n",
3504 /* A leader zombie can mean one of two things:
3506 - It exited, and there's an exit status pending
3507 available, or only the leader exited (not the whole
3508 program). In the latter case, we can't waitpid the
3509 leader's exit status until all other threads are gone.
3511 - There are 3 or more threads in the group, and a thread
3512 other than the leader exec'd. On an exec, the Linux
3513 kernel destroys all other threads (except the execing
3514 one) in the thread group, and resets the execing thread's
3515 tid to the tgid. No exit notification is sent for the
3516 execing thread -- from the ptracer's perspective, it
3517 appears as though the execing thread just vanishes.
3518 Until we reap all other threads except the leader and the
3519 execing thread, the leader will be zombie, and the
3520 execing thread will be in `D (disc sleep)'. As soon as
3521 all other threads are reaped, the execing thread changes
3522 it's tid to the tgid, and the previous (zombie) leader
3523 vanishes, giving place to the "new" leader. We could try
3524 distinguishing the exit and exec cases, by waiting once
3525 more, and seeing if something comes out, but it doesn't
3526 sound useful. The previous leader _does_ go away, and
3527 we'll re-add the new one once we see the exec event
3528 (which is just the same as what would happen if the
3529 previous leader did exit voluntarily before some other
3532 if (debug_linux_nat)
3533 fprintf_unfiltered (gdb_stdlog,
3534 "CZL: Thread group leader %d vanished.\n",
3536 exit_lwp (leader_lp);
3542 linux_nat_wait_1 (struct target_ops *ops,
3543 ptid_t ptid, struct target_waitstatus *ourstatus,
3546 static sigset_t prev_mask;
3547 enum resume_kind last_resume_kind;
3548 struct lwp_info *lp;
3551 if (debug_linux_nat)
3552 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3554 /* The first time we get here after starting a new inferior, we may
3555 not have added it to the LWP list yet - this is the earliest
3556 moment at which we know its PID. */
3557 if (ptid_is_pid (inferior_ptid))
3559 /* Upgrade the main thread's ptid. */
3560 thread_change_ptid (inferior_ptid,
3561 BUILD_LWP (GET_PID (inferior_ptid),
3562 GET_PID (inferior_ptid)));
3564 lp = add_lwp (inferior_ptid);
3568 /* Make sure SIGCHLD is blocked. */
3569 block_child_signals (&prev_mask);
3575 /* First check if there is a LWP with a wait status pending. */
3576 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3578 /* Any LWP in the PTID group that's been resumed will do. */
3579 lp = iterate_over_lwps (ptid, status_callback, NULL);
3582 if (debug_linux_nat && lp->status)
3583 fprintf_unfiltered (gdb_stdlog,
3584 "LLW: Using pending wait status %s for %s.\n",
3585 status_to_str (lp->status),
3586 target_pid_to_str (lp->ptid));
3589 else if (is_lwp (ptid))
3591 if (debug_linux_nat)
3592 fprintf_unfiltered (gdb_stdlog,
3593 "LLW: Waiting for specific LWP %s.\n",
3594 target_pid_to_str (ptid));
3596 /* We have a specific LWP to check. */
3597 lp = find_lwp_pid (ptid);
3600 if (debug_linux_nat && lp->status)
3601 fprintf_unfiltered (gdb_stdlog,
3602 "LLW: Using pending wait status %s for %s.\n",
3603 status_to_str (lp->status),
3604 target_pid_to_str (lp->ptid));
3606 /* We check for lp->waitstatus in addition to lp->status,
3607 because we can have pending process exits recorded in
3608 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3609 an additional lp->status_p flag. */
3610 if (lp->status == 0 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3614 if (lp && lp->signalled && lp->last_resume_kind != resume_stop)
3616 /* A pending SIGSTOP may interfere with the normal stream of
3617 events. In a typical case where interference is a problem,
3618 we have a SIGSTOP signal pending for LWP A while
3619 single-stepping it, encounter an event in LWP B, and take the
3620 pending SIGSTOP while trying to stop LWP A. After processing
3621 the event in LWP B, LWP A is continued, and we'll never see
3622 the SIGTRAP associated with the last time we were
3623 single-stepping LWP A. */
3625 /* Resume the thread. It should halt immediately returning the
3627 registers_changed ();
3628 if (linux_nat_prepare_to_resume != NULL)
3629 linux_nat_prepare_to_resume (lp);
3630 linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
3631 lp->step, TARGET_SIGNAL_0);
3632 if (debug_linux_nat)
3633 fprintf_unfiltered (gdb_stdlog,
3634 "LLW: %s %s, 0, 0 (expect SIGSTOP)\n",
3635 lp->step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3636 target_pid_to_str (lp->ptid));
3638 gdb_assert (lp->resumed);
3640 /* Catch the pending SIGSTOP. */
3641 status = lp->status;
3644 stop_wait_callback (lp, NULL);
3646 /* If the lp->status field isn't empty, we caught another signal
3647 while flushing the SIGSTOP. Return it back to the event
3648 queue of the LWP, as we already have an event to handle. */
3651 if (debug_linux_nat)
3652 fprintf_unfiltered (gdb_stdlog,
3653 "LLW: kill %s, %s\n",
3654 target_pid_to_str (lp->ptid),
3655 status_to_str (lp->status));
3656 kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (lp->status));
3659 lp->status = status;
3662 if (!target_can_async_p ())
3664 /* Causes SIGINT to be passed on to the attached process. */
3668 /* But if we don't find a pending event, we'll have to wait. */
3674 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3677 - If the thread group leader exits while other threads in the
3678 thread group still exist, waitpid(TGID, ...) hangs. That
3679 waitpid won't return an exit status until the other threads
3680 in the group are reapped.
3682 - When a non-leader thread execs, that thread just vanishes
3683 without reporting an exit (so we'd hang if we waited for it
3684 explicitly in that case). The exec event is reported to
3688 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3689 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3690 lwpid = my_waitpid (-1, &status, WNOHANG);
3692 if (debug_linux_nat)
3693 fprintf_unfiltered (gdb_stdlog,
3694 "LNW: waitpid(-1, ...) returned %d, %s\n",
3695 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3699 /* If this is true, then we paused LWPs momentarily, and may
3700 now have pending events to handle. */
3703 if (debug_linux_nat)
3705 fprintf_unfiltered (gdb_stdlog,
3706 "LLW: waitpid %ld received %s\n",
3707 (long) lwpid, status_to_str (status));
3710 lp = linux_nat_filter_event (lwpid, status, &new_pending);
3712 /* STATUS is now no longer valid, use LP->STATUS instead. */
3715 if (lp && !ptid_match (lp->ptid, ptid))
3717 gdb_assert (lp->resumed);
3719 if (debug_linux_nat)
3721 "LWP %ld got an event %06x, leaving pending.\n",
3722 ptid_get_lwp (lp->ptid), lp->status);
3724 if (WIFSTOPPED (lp->status))
3726 if (WSTOPSIG (lp->status) != SIGSTOP)
3728 /* Cancel breakpoint hits. The breakpoint may
3729 be removed before we fetch events from this
3730 process to report to the core. It is best
3731 not to assume the moribund breakpoints
3732 heuristic always handles these cases --- it
3733 could be too many events go through to the
3734 core before this one is handled. All-stop
3735 always cancels breakpoint hits in all
3738 && linux_nat_lp_status_is_event (lp)
3739 && cancel_breakpoint (lp))
3741 /* Throw away the SIGTRAP. */
3744 if (debug_linux_nat)
3746 "LLW: LWP %ld hit a breakpoint while"
3747 " waiting for another process;"
3749 ptid_get_lwp (lp->ptid));
3759 else if (WIFEXITED (lp->status) || WIFSIGNALED (lp->status))
3761 if (debug_linux_nat)
3763 "Process %ld exited while stopping LWPs\n",
3764 ptid_get_lwp (lp->ptid));
3766 /* This was the last lwp in the process. Since
3767 events are serialized to GDB core, and we can't
3768 report this one right now, but GDB core and the
3769 other target layers will want to be notified
3770 about the exit code/signal, leave the status
3771 pending for the next time we're able to report
3774 /* Prevent trying to stop this thread again. We'll
3775 never try to resume it because it has a pending
3779 /* Dead LWP's aren't expected to reported a pending
3783 /* Store the pending event in the waitstatus as
3784 well, because W_EXITCODE(0,0) == 0. */
3785 store_waitstatus (&lp->waitstatus, lp->status);
3794 /* Some LWP now has a pending event. Go all the way
3795 back to check it. */
3801 /* We got an event to report to the core. */
3805 /* Retry until nothing comes out of waitpid. A single
3806 SIGCHLD can indicate more than one child stopped. */
3810 /* Check for zombie thread group leaders. Those can't be reaped
3811 until all other threads in the thread group are. */
3812 check_zombie_leaders ();
3814 /* If there are no resumed children left, bail. We'd be stuck
3815 forever in the sigsuspend call below otherwise. */
3816 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3818 if (debug_linux_nat)
3819 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3821 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3823 if (!target_can_async_p ())
3824 clear_sigint_trap ();
3826 restore_child_signals_mask (&prev_mask);
3827 return minus_one_ptid;
3830 /* No interesting event to report to the core. */
3832 if (target_options & TARGET_WNOHANG)
3834 if (debug_linux_nat)
3835 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3837 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3838 restore_child_signals_mask (&prev_mask);
3839 return minus_one_ptid;
3842 /* We shouldn't end up here unless we want to try again. */
3843 gdb_assert (lp == NULL);
3845 /* Block until we get an event reported with SIGCHLD. */
3846 sigsuspend (&suspend_mask);
3849 if (!target_can_async_p ())
3850 clear_sigint_trap ();
3854 status = lp->status;
3857 /* Don't report signals that GDB isn't interested in, such as
3858 signals that are neither printed nor stopped upon. Stopping all
3859 threads can be a bit time-consuming so if we want decent
3860 performance with heavily multi-threaded programs, especially when
3861 they're using a high frequency timer, we'd better avoid it if we
3864 if (WIFSTOPPED (status))
3866 enum target_signal signo = target_signal_from_host (WSTOPSIG (status));
3868 /* When using hardware single-step, we need to report every signal.
3869 Otherwise, signals in pass_mask may be short-circuited. */
3871 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status)))
3873 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3874 here? It is not clear we should. GDB may not expect
3875 other threads to run. On the other hand, not resuming
3876 newly attached threads may cause an unwanted delay in
3877 getting them running. */
3878 registers_changed ();
3879 if (linux_nat_prepare_to_resume != NULL)
3880 linux_nat_prepare_to_resume (lp);
3881 linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
3883 if (debug_linux_nat)
3884 fprintf_unfiltered (gdb_stdlog,
3885 "LLW: %s %s, %s (preempt 'handle')\n",
3887 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3888 target_pid_to_str (lp->ptid),
3889 (signo != TARGET_SIGNAL_0
3890 ? strsignal (target_signal_to_host (signo))
3898 /* Only do the below in all-stop, as we currently use SIGINT
3899 to implement target_stop (see linux_nat_stop) in
3901 if (signo == TARGET_SIGNAL_INT && signal_pass_state (signo) == 0)
3903 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3904 forwarded to the entire process group, that is, all LWPs
3905 will receive it - unless they're using CLONE_THREAD to
3906 share signals. Since we only want to report it once, we
3907 mark it as ignored for all LWPs except this one. */
3908 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid)),
3909 set_ignore_sigint, NULL);
3910 lp->ignore_sigint = 0;
3913 maybe_clear_ignore_sigint (lp);
3917 /* This LWP is stopped now. */
3920 if (debug_linux_nat)
3921 fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
3922 status_to_str (status), target_pid_to_str (lp->ptid));
3926 /* Now stop all other LWP's ... */
3927 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3929 /* ... and wait until all of them have reported back that
3930 they're no longer running. */
3931 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3933 /* If we're not waiting for a specific LWP, choose an event LWP
3934 from among those that have had events. Giving equal priority
3935 to all LWPs that have had events helps prevent
3937 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3938 select_event_lwp (ptid, &lp, &status);
3940 /* Now that we've selected our final event LWP, cancel any
3941 breakpoints in other LWPs that have hit a GDB breakpoint.
3942 See the comment in cancel_breakpoints_callback to find out
3944 iterate_over_lwps (minus_one_ptid, cancel_breakpoints_callback, lp);
3946 /* We'll need this to determine whether to report a SIGSTOP as
3947 TARGET_WAITKIND_0. Need to take a copy because
3948 resume_clear_callback clears it. */
3949 last_resume_kind = lp->last_resume_kind;
3951 /* In all-stop, from the core's perspective, all LWPs are now
3952 stopped until a new resume action is sent over. */
3953 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3958 last_resume_kind = lp->last_resume_kind;
3959 resume_clear_callback (lp, NULL);
3962 if (linux_nat_status_is_event (status))
3964 if (debug_linux_nat)
3965 fprintf_unfiltered (gdb_stdlog,
3966 "LLW: trap ptid is %s.\n",
3967 target_pid_to_str (lp->ptid));
3970 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3972 *ourstatus = lp->waitstatus;
3973 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3976 store_waitstatus (ourstatus, status);
3978 if (debug_linux_nat)
3979 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3981 restore_child_signals_mask (&prev_mask);
3983 if (last_resume_kind == resume_stop
3984 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3985 && WSTOPSIG (status) == SIGSTOP)
3987 /* A thread that has been requested to stop by GDB with
3988 target_stop, and it stopped cleanly, so report as SIG0. The
3989 use of SIGSTOP is an implementation detail. */
3990 ourstatus->value.sig = TARGET_SIGNAL_0;
3993 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3994 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3997 lp->core = linux_common_core_of_thread (lp->ptid);
4002 /* Resume LWPs that are currently stopped without any pending status
4003 to report, but are resumed from the core's perspective. */
4006 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
4008 ptid_t *wait_ptid_p = data;
4013 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
4015 struct regcache *regcache = get_thread_regcache (lp->ptid);
4016 struct gdbarch *gdbarch = get_regcache_arch (regcache);
4017 CORE_ADDR pc = regcache_read_pc (regcache);
4019 gdb_assert (is_executing (lp->ptid));
4021 /* Don't bother if there's a breakpoint at PC that we'd hit
4022 immediately, and we're not waiting for this LWP. */
4023 if (!ptid_match (lp->ptid, *wait_ptid_p))
4025 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
4029 if (debug_linux_nat)
4030 fprintf_unfiltered (gdb_stdlog,
4031 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
4032 target_pid_to_str (lp->ptid),
4033 paddress (gdbarch, pc),
4036 registers_changed ();
4037 if (linux_nat_prepare_to_resume != NULL)
4038 linux_nat_prepare_to_resume (lp);
4039 linux_ops->to_resume (linux_ops, pid_to_ptid (GET_LWP (lp->ptid)),
4040 lp->step, TARGET_SIGNAL_0);
4042 memset (&lp->siginfo, 0, sizeof (lp->siginfo));
4043 lp->stopped_by_watchpoint = 0;
4050 linux_nat_wait (struct target_ops *ops,
4051 ptid_t ptid, struct target_waitstatus *ourstatus,
4056 if (debug_linux_nat)
4057 fprintf_unfiltered (gdb_stdlog,
4058 "linux_nat_wait: [%s]\n", target_pid_to_str (ptid));
4060 /* Flush the async file first. */
4061 if (target_can_async_p ())
4062 async_file_flush ();
4064 /* Resume LWPs that are currently stopped without any pending status
4065 to report, but are resumed from the core's perspective. LWPs get
4066 in this state if we find them stopping at a time we're not
4067 interested in reporting the event (target_wait on a
4068 specific_process, for example, see linux_nat_wait_1), and
4069 meanwhile the event became uninteresting. Don't bother resuming
4070 LWPs we're not going to wait for if they'd stop immediately. */
4072 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
4074 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
4076 /* If we requested any event, and something came out, assume there
4077 may be more. If we requested a specific lwp or process, also
4078 assume there may be more. */
4079 if (target_can_async_p ()
4080 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
4081 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
4082 || !ptid_equal (ptid, minus_one_ptid)))
4085 /* Get ready for the next event. */
4086 if (target_can_async_p ())
4087 target_async (inferior_event_handler, 0);
4093 kill_callback (struct lwp_info *lp, void *data)
4095 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
4098 kill (GET_LWP (lp->ptid), SIGKILL);
4099 if (debug_linux_nat)
4100 fprintf_unfiltered (gdb_stdlog,
4101 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
4102 target_pid_to_str (lp->ptid),
4103 errno ? safe_strerror (errno) : "OK");
4105 /* Some kernels ignore even SIGKILL for processes under ptrace. */
4108 ptrace (PTRACE_KILL, GET_LWP (lp->ptid), 0, 0);
4109 if (debug_linux_nat)
4110 fprintf_unfiltered (gdb_stdlog,
4111 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
4112 target_pid_to_str (lp->ptid),
4113 errno ? safe_strerror (errno) : "OK");
4119 kill_wait_callback (struct lwp_info *lp, void *data)
4123 /* We must make sure that there are no pending events (delayed
4124 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
4125 program doesn't interfere with any following debugging session. */
4127 /* For cloned processes we must check both with __WCLONE and
4128 without, since the exit status of a cloned process isn't reported
4134 pid = my_waitpid (GET_LWP (lp->ptid), NULL, __WCLONE);
4135 if (pid != (pid_t) -1)
4137 if (debug_linux_nat)
4138 fprintf_unfiltered (gdb_stdlog,
4139 "KWC: wait %s received unknown.\n",
4140 target_pid_to_str (lp->ptid));
4141 /* The Linux kernel sometimes fails to kill a thread
4142 completely after PTRACE_KILL; that goes from the stop
4143 point in do_fork out to the one in
4144 get_signal_to_deliever and waits again. So kill it
4146 kill_callback (lp, NULL);
4149 while (pid == GET_LWP (lp->ptid));
4151 gdb_assert (pid == -1 && errno == ECHILD);
4156 pid = my_waitpid (GET_LWP (lp->ptid), NULL, 0);
4157 if (pid != (pid_t) -1)
4159 if (debug_linux_nat)
4160 fprintf_unfiltered (gdb_stdlog,
4161 "KWC: wait %s received unk.\n",
4162 target_pid_to_str (lp->ptid));
4163 /* See the call to kill_callback above. */
4164 kill_callback (lp, NULL);
4167 while (pid == GET_LWP (lp->ptid));
4169 gdb_assert (pid == -1 && errno == ECHILD);
4174 linux_nat_kill (struct target_ops *ops)
4176 struct target_waitstatus last;
4180 /* If we're stopped while forking and we haven't followed yet,
4181 kill the other task. We need to do this first because the
4182 parent will be sleeping if this is a vfork. */
4184 get_last_target_status (&last_ptid, &last);
4186 if (last.kind == TARGET_WAITKIND_FORKED
4187 || last.kind == TARGET_WAITKIND_VFORKED)
4189 ptrace (PT_KILL, PIDGET (last.value.related_pid), 0, 0);
4193 if (forks_exist_p ())
4194 linux_fork_killall ();
4197 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
4199 /* Stop all threads before killing them, since ptrace requires
4200 that the thread is stopped to sucessfully PTRACE_KILL. */
4201 iterate_over_lwps (ptid, stop_callback, NULL);
4202 /* ... and wait until all of them have reported back that
4203 they're no longer running. */
4204 iterate_over_lwps (ptid, stop_wait_callback, NULL);
4206 /* Kill all LWP's ... */
4207 iterate_over_lwps (ptid, kill_callback, NULL);
4209 /* ... and wait until we've flushed all events. */
4210 iterate_over_lwps (ptid, kill_wait_callback, NULL);
4213 target_mourn_inferior ();
4217 linux_nat_mourn_inferior (struct target_ops *ops)
4219 purge_lwp_list (ptid_get_pid (inferior_ptid));
4221 if (! forks_exist_p ())
4222 /* Normal case, no other forks available. */
4223 linux_ops->to_mourn_inferior (ops);
4225 /* Multi-fork case. The current inferior_ptid has exited, but
4226 there are other viable forks to debug. Delete the exiting
4227 one and context-switch to the first available. */
4228 linux_fork_mourn_inferior ();
4231 /* Convert a native/host siginfo object, into/from the siginfo in the
4232 layout of the inferiors' architecture. */
4235 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
4239 if (linux_nat_siginfo_fixup != NULL)
4240 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
4242 /* If there was no callback, or the callback didn't do anything,
4243 then just do a straight memcpy. */
4247 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
4249 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
4254 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
4255 const char *annex, gdb_byte *readbuf,
4256 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
4260 gdb_byte inf_siginfo[sizeof (siginfo_t)];
4262 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
4263 gdb_assert (readbuf || writebuf);
4265 pid = GET_LWP (inferior_ptid);
4267 pid = GET_PID (inferior_ptid);
4269 if (offset > sizeof (siginfo))
4273 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
4277 /* When GDB is built as a 64-bit application, ptrace writes into
4278 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
4279 inferior with a 64-bit GDB should look the same as debugging it
4280 with a 32-bit GDB, we need to convert it. GDB core always sees
4281 the converted layout, so any read/write will have to be done
4283 siginfo_fixup (&siginfo, inf_siginfo, 0);
4285 if (offset + len > sizeof (siginfo))
4286 len = sizeof (siginfo) - offset;
4288 if (readbuf != NULL)
4289 memcpy (readbuf, inf_siginfo + offset, len);
4292 memcpy (inf_siginfo + offset, writebuf, len);
4294 /* Convert back to ptrace layout before flushing it out. */
4295 siginfo_fixup (&siginfo, inf_siginfo, 1);
4298 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
4307 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
4308 const char *annex, gdb_byte *readbuf,
4309 const gdb_byte *writebuf,
4310 ULONGEST offset, LONGEST len)
4312 struct cleanup *old_chain;
4315 if (object == TARGET_OBJECT_SIGNAL_INFO)
4316 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
4319 /* The target is connected but no live inferior is selected. Pass
4320 this request down to a lower stratum (e.g., the executable
4322 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
4325 old_chain = save_inferior_ptid ();
4327 if (is_lwp (inferior_ptid))
4328 inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid));
4330 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
4333 do_cleanups (old_chain);
4338 linux_thread_alive (ptid_t ptid)
4342 gdb_assert (is_lwp (ptid));
4344 /* Send signal 0 instead of anything ptrace, because ptracing a
4345 running thread errors out claiming that the thread doesn't
4347 err = kill_lwp (GET_LWP (ptid), 0);
4349 if (debug_linux_nat)
4350 fprintf_unfiltered (gdb_stdlog,
4351 "LLTA: KILL(SIG0) %s (%s)\n",
4352 target_pid_to_str (ptid),
4353 err ? safe_strerror (tmp_errno) : "OK");
4362 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
4364 return linux_thread_alive (ptid);
4368 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
4370 static char buf[64];
4373 && (GET_PID (ptid) != GET_LWP (ptid)
4374 || num_lwps (GET_PID (ptid)) > 1))
4376 snprintf (buf, sizeof (buf), "LWP %ld", GET_LWP (ptid));
4380 return normal_pid_to_str (ptid);
4384 linux_nat_thread_name (struct thread_info *thr)
4386 int pid = ptid_get_pid (thr->ptid);
4387 long lwp = ptid_get_lwp (thr->ptid);
4388 #define FORMAT "/proc/%d/task/%ld/comm"
4389 char buf[sizeof (FORMAT) + 30];
4391 char *result = NULL;
4393 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
4394 comm_file = fopen (buf, "r");
4397 /* Not exported by the kernel, so we define it here. */
4399 static char line[COMM_LEN + 1];
4401 if (fgets (line, sizeof (line), comm_file))
4403 char *nl = strchr (line, '\n');
4420 /* Accepts an integer PID; Returns a string representing a file that
4421 can be opened to get the symbols for the child process. */
4424 linux_child_pid_to_exec_file (int pid)
4426 char *name1, *name2;
4428 name1 = xmalloc (MAXPATHLEN);
4429 name2 = xmalloc (MAXPATHLEN);
4430 make_cleanup (xfree, name1);
4431 make_cleanup (xfree, name2);
4432 memset (name2, 0, MAXPATHLEN);
4434 sprintf (name1, "/proc/%d/exe", pid);
4435 if (readlink (name1, name2, MAXPATHLEN) > 0)
4441 /* Records the thread's register state for the corefile note
4445 linux_nat_collect_thread_registers (const struct regcache *regcache,
4446 ptid_t ptid, bfd *obfd,
4447 char *note_data, int *note_size,
4448 enum target_signal stop_signal)
4450 struct gdbarch *gdbarch = get_regcache_arch (regcache);
4451 const struct regset *regset;
4453 gdb_gregset_t gregs;
4454 gdb_fpregset_t fpregs;
4456 core_regset_p = gdbarch_regset_from_core_section_p (gdbarch);
4459 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg",
4461 != NULL && regset->collect_regset != NULL)
4462 regset->collect_regset (regset, regcache, -1, &gregs, sizeof (gregs));
4464 fill_gregset (regcache, &gregs, -1);
4466 note_data = (char *) elfcore_write_prstatus
4467 (obfd, note_data, note_size, ptid_get_lwp (ptid),
4468 target_signal_to_host (stop_signal), &gregs);
4471 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
4473 != NULL && regset->collect_regset != NULL)
4474 regset->collect_regset (regset, regcache, -1, &fpregs, sizeof (fpregs));
4476 fill_fpregset (regcache, &fpregs, -1);
4478 note_data = (char *) elfcore_write_prfpreg (obfd, note_data, note_size,
4479 &fpregs, sizeof (fpregs));
4484 /* Fills the "to_make_corefile_note" target vector. Builds the note
4485 section for a corefile, and returns it in a malloc buffer. */
4488 linux_nat_make_corefile_notes (bfd *obfd, int *note_size)
4490 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4491 converted to gdbarch_core_regset_sections, this function can go away. */
4492 return linux_make_corefile_notes (target_gdbarch, obfd, note_size,
4493 linux_nat_collect_thread_registers);
4496 /* Implement the to_xfer_partial interface for memory reads using the /proc
4497 filesystem. Because we can use a single read() call for /proc, this
4498 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4499 but it doesn't support writes. */
4502 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
4503 const char *annex, gdb_byte *readbuf,
4504 const gdb_byte *writebuf,
4505 ULONGEST offset, LONGEST len)
4511 if (object != TARGET_OBJECT_MEMORY || !readbuf)
4514 /* Don't bother for one word. */
4515 if (len < 3 * sizeof (long))
4518 /* We could keep this file open and cache it - possibly one per
4519 thread. That requires some juggling, but is even faster. */
4520 sprintf (filename, "/proc/%d/mem", PIDGET (inferior_ptid));
4521 fd = open (filename, O_RDONLY | O_LARGEFILE);
4525 /* If pread64 is available, use it. It's faster if the kernel
4526 supports it (only one syscall), and it's 64-bit safe even on
4527 32-bit platforms (for instance, SPARC debugging a SPARC64
4530 if (pread64 (fd, readbuf, len, offset) != len)
4532 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
4543 /* Enumerate spufs IDs for process PID. */
4545 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, LONGEST len)
4547 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
4549 LONGEST written = 0;
4552 struct dirent *entry;
4554 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4555 dir = opendir (path);
4560 while ((entry = readdir (dir)) != NULL)
4566 fd = atoi (entry->d_name);
4570 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4571 if (stat (path, &st) != 0)
4573 if (!S_ISDIR (st.st_mode))
4576 if (statfs (path, &stfs) != 0)
4578 if (stfs.f_type != SPUFS_MAGIC)
4581 if (pos >= offset && pos + 4 <= offset + len)
4583 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4593 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4594 object type, using the /proc file system. */
4596 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
4597 const char *annex, gdb_byte *readbuf,
4598 const gdb_byte *writebuf,
4599 ULONGEST offset, LONGEST len)
4604 int pid = PIDGET (inferior_ptid);
4611 return spu_enumerate_spu_ids (pid, readbuf, offset, len);
4614 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4615 fd = open (buf, writebuf? O_WRONLY : O_RDONLY);
4620 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4627 ret = write (fd, writebuf, (size_t) len);
4629 ret = read (fd, readbuf, (size_t) len);
4636 /* Parse LINE as a signal set and add its set bits to SIGS. */
4639 add_line_to_sigset (const char *line, sigset_t *sigs)
4641 int len = strlen (line) - 1;
4645 if (line[len] != '\n')
4646 error (_("Could not parse signal set: %s"), line);
4654 if (*p >= '0' && *p <= '9')
4656 else if (*p >= 'a' && *p <= 'f')
4657 digit = *p - 'a' + 10;
4659 error (_("Could not parse signal set: %s"), line);
4664 sigaddset (sigs, signum + 1);
4666 sigaddset (sigs, signum + 2);
4668 sigaddset (sigs, signum + 3);
4670 sigaddset (sigs, signum + 4);
4676 /* Find process PID's pending signals from /proc/pid/status and set
4680 linux_proc_pending_signals (int pid, sigset_t *pending,
4681 sigset_t *blocked, sigset_t *ignored)
4684 char buffer[MAXPATHLEN], fname[MAXPATHLEN];
4685 struct cleanup *cleanup;
4687 sigemptyset (pending);
4688 sigemptyset (blocked);
4689 sigemptyset (ignored);
4690 sprintf (fname, "/proc/%d/status", pid);
4691 procfile = fopen (fname, "r");
4692 if (procfile == NULL)
4693 error (_("Could not open %s"), fname);
4694 cleanup = make_cleanup_fclose (procfile);
4696 while (fgets (buffer, MAXPATHLEN, procfile) != NULL)
4698 /* Normal queued signals are on the SigPnd line in the status
4699 file. However, 2.6 kernels also have a "shared" pending
4700 queue for delivering signals to a thread group, so check for
4703 Unfortunately some Red Hat kernels include the shared pending
4704 queue but not the ShdPnd status field. */
4706 if (strncmp (buffer, "SigPnd:\t", 8) == 0)
4707 add_line_to_sigset (buffer + 8, pending);
4708 else if (strncmp (buffer, "ShdPnd:\t", 8) == 0)
4709 add_line_to_sigset (buffer + 8, pending);
4710 else if (strncmp (buffer, "SigBlk:\t", 8) == 0)
4711 add_line_to_sigset (buffer + 8, blocked);
4712 else if (strncmp (buffer, "SigIgn:\t", 8) == 0)
4713 add_line_to_sigset (buffer + 8, ignored);
4716 do_cleanups (cleanup);
4720 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4721 const char *annex, gdb_byte *readbuf,
4722 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
4724 gdb_assert (object == TARGET_OBJECT_OSDATA);
4726 return linux_common_xfer_osdata (annex, readbuf, offset, len);
4730 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4731 const char *annex, gdb_byte *readbuf,
4732 const gdb_byte *writebuf, ULONGEST offset, LONGEST len)
4736 if (object == TARGET_OBJECT_AUXV)
4737 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4740 if (object == TARGET_OBJECT_OSDATA)
4741 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4744 if (object == TARGET_OBJECT_SPU)
4745 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4748 /* GDB calculates all the addresses in possibly larget width of the address.
4749 Address width needs to be masked before its final use - either by
4750 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4752 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4754 if (object == TARGET_OBJECT_MEMORY)
4756 int addr_bit = gdbarch_addr_bit (target_gdbarch);
4758 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4759 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4762 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4767 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4772 cleanup_target_stop (void *arg)
4774 ptid_t *ptid = (ptid_t *) arg;
4776 gdb_assert (arg != NULL);
4779 target_resume (*ptid, 0, TARGET_SIGNAL_0);
4782 static VEC(static_tracepoint_marker_p) *
4783 linux_child_static_tracepoint_markers_by_strid (const char *strid)
4785 char s[IPA_CMD_BUF_SIZE];
4786 struct cleanup *old_chain;
4787 int pid = ptid_get_pid (inferior_ptid);
4788 VEC(static_tracepoint_marker_p) *markers = NULL;
4789 struct static_tracepoint_marker *marker = NULL;
4791 ptid_t ptid = ptid_build (pid, 0, 0);
4796 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4797 s[sizeof ("qTfSTM")] = 0;
4799 agent_run_command (pid, s, strlen (s) + 1);
4801 old_chain = make_cleanup (free_current_marker, &marker);
4802 make_cleanup (cleanup_target_stop, &ptid);
4807 marker = XCNEW (struct static_tracepoint_marker);
4811 parse_static_tracepoint_marker_definition (p, &p, marker);
4813 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4815 VEC_safe_push (static_tracepoint_marker_p,
4821 release_static_tracepoint_marker (marker);
4822 memset (marker, 0, sizeof (*marker));
4825 while (*p++ == ','); /* comma-separated list */
4827 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4828 s[sizeof ("qTsSTM")] = 0;
4829 agent_run_command (pid, s, strlen (s) + 1);
4833 do_cleanups (old_chain);
4838 /* Create a prototype generic GNU/Linux target. The client can override
4839 it with local methods. */
4842 linux_target_install_ops (struct target_ops *t)
4844 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4845 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4846 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4847 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4848 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4849 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4850 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4851 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4852 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4853 t->to_post_attach = linux_child_post_attach;
4854 t->to_follow_fork = linux_child_follow_fork;
4855 t->to_make_corefile_notes = linux_nat_make_corefile_notes;
4857 super_xfer_partial = t->to_xfer_partial;
4858 t->to_xfer_partial = linux_xfer_partial;
4860 t->to_static_tracepoint_markers_by_strid
4861 = linux_child_static_tracepoint_markers_by_strid;
4867 struct target_ops *t;
4869 t = inf_ptrace_target ();
4870 linux_target_install_ops (t);
4876 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4878 struct target_ops *t;
4880 t = inf_ptrace_trad_target (register_u_offset);
4881 linux_target_install_ops (t);
4886 /* target_is_async_p implementation. */
4889 linux_nat_is_async_p (void)
4891 /* NOTE: palves 2008-03-21: We're only async when the user requests
4892 it explicitly with the "set target-async" command.
4893 Someday, linux will always be async. */
4894 return target_async_permitted;
4897 /* target_can_async_p implementation. */
4900 linux_nat_can_async_p (void)
4902 /* NOTE: palves 2008-03-21: We're only async when the user requests
4903 it explicitly with the "set target-async" command.
4904 Someday, linux will always be async. */
4905 return target_async_permitted;
4909 linux_nat_supports_non_stop (void)
4914 /* True if we want to support multi-process. To be removed when GDB
4915 supports multi-exec. */
4917 int linux_multi_process = 1;
4920 linux_nat_supports_multi_process (void)
4922 return linux_multi_process;
4926 linux_nat_supports_disable_randomization (void)
4928 #ifdef HAVE_PERSONALITY
4935 static int async_terminal_is_ours = 1;
4937 /* target_terminal_inferior implementation. */
4940 linux_nat_terminal_inferior (void)
4942 if (!target_is_async_p ())
4944 /* Async mode is disabled. */
4945 terminal_inferior ();
4949 terminal_inferior ();
4951 /* Calls to target_terminal_*() are meant to be idempotent. */
4952 if (!async_terminal_is_ours)
4955 delete_file_handler (input_fd);
4956 async_terminal_is_ours = 0;
4960 /* target_terminal_ours implementation. */
4963 linux_nat_terminal_ours (void)
4965 if (!target_is_async_p ())
4967 /* Async mode is disabled. */
4972 /* GDB should never give the terminal to the inferior if the
4973 inferior is running in the background (run&, continue&, etc.),
4974 but claiming it sure should. */
4977 if (async_terminal_is_ours)
4980 clear_sigint_trap ();
4981 add_file_handler (input_fd, stdin_event_handler, 0);
4982 async_terminal_is_ours = 1;
4985 static void (*async_client_callback) (enum inferior_event_type event_type,
4987 static void *async_client_context;
4989 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4990 so we notice when any child changes state, and notify the
4991 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4992 above to wait for the arrival of a SIGCHLD. */
4995 sigchld_handler (int signo)
4997 int old_errno = errno;
4999 if (debug_linux_nat)
5000 ui_file_write_async_safe (gdb_stdlog,
5001 "sigchld\n", sizeof ("sigchld\n") - 1);
5003 if (signo == SIGCHLD
5004 && linux_nat_event_pipe[0] != -1)
5005 async_file_mark (); /* Let the event loop know that there are
5006 events to handle. */
5011 /* Callback registered with the target events file descriptor. */
5014 handle_target_event (int error, gdb_client_data client_data)
5016 (*async_client_callback) (INF_REG_EVENT, async_client_context);
5019 /* Create/destroy the target events pipe. Returns previous state. */
5022 linux_async_pipe (int enable)
5024 int previous = (linux_nat_event_pipe[0] != -1);
5026 if (previous != enable)
5030 block_child_signals (&prev_mask);
5034 if (pipe (linux_nat_event_pipe) == -1)
5035 internal_error (__FILE__, __LINE__,
5036 "creating event pipe failed.");
5038 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
5039 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
5043 close (linux_nat_event_pipe[0]);
5044 close (linux_nat_event_pipe[1]);
5045 linux_nat_event_pipe[0] = -1;
5046 linux_nat_event_pipe[1] = -1;
5049 restore_child_signals_mask (&prev_mask);
5055 /* target_async implementation. */
5058 linux_nat_async (void (*callback) (enum inferior_event_type event_type,
5059 void *context), void *context)
5061 if (callback != NULL)
5063 async_client_callback = callback;
5064 async_client_context = context;
5065 if (!linux_async_pipe (1))
5067 add_file_handler (linux_nat_event_pipe[0],
5068 handle_target_event, NULL);
5069 /* There may be pending events to handle. Tell the event loop
5076 async_client_callback = callback;
5077 async_client_context = context;
5078 delete_file_handler (linux_nat_event_pipe[0]);
5079 linux_async_pipe (0);
5084 /* Stop an LWP, and push a TARGET_SIGNAL_0 stop status if no other
5088 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
5092 ptid_t ptid = lwp->ptid;
5094 if (debug_linux_nat)
5095 fprintf_unfiltered (gdb_stdlog,
5096 "LNSL: running -> suspending %s\n",
5097 target_pid_to_str (lwp->ptid));
5100 if (lwp->last_resume_kind == resume_stop)
5102 if (debug_linux_nat)
5103 fprintf_unfiltered (gdb_stdlog,
5104 "linux-nat: already stopping LWP %ld at "
5106 ptid_get_lwp (lwp->ptid));
5110 stop_callback (lwp, NULL);
5111 lwp->last_resume_kind = resume_stop;
5115 /* Already known to be stopped; do nothing. */
5117 if (debug_linux_nat)
5119 if (find_thread_ptid (lwp->ptid)->stop_requested)
5120 fprintf_unfiltered (gdb_stdlog,
5121 "LNSL: already stopped/stop_requested %s\n",
5122 target_pid_to_str (lwp->ptid));
5124 fprintf_unfiltered (gdb_stdlog,
5125 "LNSL: already stopped/no "
5126 "stop_requested yet %s\n",
5127 target_pid_to_str (lwp->ptid));
5134 linux_nat_stop (ptid_t ptid)
5137 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
5139 linux_ops->to_stop (ptid);
5143 linux_nat_close (int quitting)
5145 /* Unregister from the event loop. */
5146 if (linux_nat_is_async_p ())
5147 linux_nat_async (NULL, 0);
5149 if (linux_ops->to_close)
5150 linux_ops->to_close (quitting);
5153 /* When requests are passed down from the linux-nat layer to the
5154 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
5155 used. The address space pointer is stored in the inferior object,
5156 but the common code that is passed such ptid can't tell whether
5157 lwpid is a "main" process id or not (it assumes so). We reverse
5158 look up the "main" process id from the lwp here. */
5160 static struct address_space *
5161 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
5163 struct lwp_info *lwp;
5164 struct inferior *inf;
5167 pid = GET_LWP (ptid);
5168 if (GET_LWP (ptid) == 0)
5170 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
5172 lwp = find_lwp_pid (ptid);
5173 pid = GET_PID (lwp->ptid);
5177 /* A (pid,lwpid,0) ptid. */
5178 pid = GET_PID (ptid);
5181 inf = find_inferior_pid (pid);
5182 gdb_assert (inf != NULL);
5186 /* Return the cached value of the processor core for thread PTID. */
5189 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
5191 struct lwp_info *info = find_lwp_pid (ptid);
5199 linux_nat_add_target (struct target_ops *t)
5201 /* Save the provided single-threaded target. We save this in a separate
5202 variable because another target we've inherited from (e.g. inf-ptrace)
5203 may have saved a pointer to T; we want to use it for the final
5204 process stratum target. */
5205 linux_ops_saved = *t;
5206 linux_ops = &linux_ops_saved;
5208 /* Override some methods for multithreading. */
5209 t->to_create_inferior = linux_nat_create_inferior;
5210 t->to_attach = linux_nat_attach;
5211 t->to_detach = linux_nat_detach;
5212 t->to_resume = linux_nat_resume;
5213 t->to_wait = linux_nat_wait;
5214 t->to_pass_signals = linux_nat_pass_signals;
5215 t->to_xfer_partial = linux_nat_xfer_partial;
5216 t->to_kill = linux_nat_kill;
5217 t->to_mourn_inferior = linux_nat_mourn_inferior;
5218 t->to_thread_alive = linux_nat_thread_alive;
5219 t->to_pid_to_str = linux_nat_pid_to_str;
5220 t->to_thread_name = linux_nat_thread_name;
5221 t->to_has_thread_control = tc_schedlock;
5222 t->to_thread_address_space = linux_nat_thread_address_space;
5223 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
5224 t->to_stopped_data_address = linux_nat_stopped_data_address;
5226 t->to_can_async_p = linux_nat_can_async_p;
5227 t->to_is_async_p = linux_nat_is_async_p;
5228 t->to_supports_non_stop = linux_nat_supports_non_stop;
5229 t->to_async = linux_nat_async;
5230 t->to_terminal_inferior = linux_nat_terminal_inferior;
5231 t->to_terminal_ours = linux_nat_terminal_ours;
5232 t->to_close = linux_nat_close;
5234 /* Methods for non-stop support. */
5235 t->to_stop = linux_nat_stop;
5237 t->to_supports_multi_process = linux_nat_supports_multi_process;
5239 t->to_supports_disable_randomization
5240 = linux_nat_supports_disable_randomization;
5242 t->to_core_of_thread = linux_nat_core_of_thread;
5244 /* We don't change the stratum; this target will sit at
5245 process_stratum and thread_db will set at thread_stratum. This
5246 is a little strange, since this is a multi-threaded-capable
5247 target, but we want to be on the stack below thread_db, and we
5248 also want to be used for single-threaded processes. */
5253 /* Register a method to call whenever a new thread is attached. */
5255 linux_nat_set_new_thread (struct target_ops *t,
5256 void (*new_thread) (struct lwp_info *))
5258 /* Save the pointer. We only support a single registered instance
5259 of the GNU/Linux native target, so we do not need to map this to
5261 linux_nat_new_thread = new_thread;
5264 /* Register a method that converts a siginfo object between the layout
5265 that ptrace returns, and the layout in the architecture of the
5268 linux_nat_set_siginfo_fixup (struct target_ops *t,
5269 int (*siginfo_fixup) (siginfo_t *,
5273 /* Save the pointer. */
5274 linux_nat_siginfo_fixup = siginfo_fixup;
5277 /* Register a method to call prior to resuming a thread. */
5280 linux_nat_set_prepare_to_resume (struct target_ops *t,
5281 void (*prepare_to_resume) (struct lwp_info *))
5283 /* Save the pointer. */
5284 linux_nat_prepare_to_resume = prepare_to_resume;
5287 /* Return the saved siginfo associated with PTID. */
5289 linux_nat_get_siginfo (ptid_t ptid)
5291 struct lwp_info *lp = find_lwp_pid (ptid);
5293 gdb_assert (lp != NULL);
5295 return &lp->siginfo;
5298 /* Provide a prototype to silence -Wmissing-prototypes. */
5299 extern initialize_file_ftype _initialize_linux_nat;
5302 _initialize_linux_nat (void)
5304 add_setshow_zinteger_cmd ("lin-lwp", class_maintenance,
5305 &debug_linux_nat, _("\
5306 Set debugging of GNU/Linux lwp module."), _("\
5307 Show debugging of GNU/Linux lwp module."), _("\
5308 Enables printf debugging output."),
5310 show_debug_linux_nat,
5311 &setdebuglist, &showdebuglist);
5313 /* Save this mask as the default. */
5314 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
5316 /* Install a SIGCHLD handler. */
5317 sigchld_action.sa_handler = sigchld_handler;
5318 sigemptyset (&sigchld_action.sa_mask);
5319 sigchld_action.sa_flags = SA_RESTART;
5321 /* Make it the default. */
5322 sigaction (SIGCHLD, &sigchld_action, NULL);
5324 /* Make sure we don't block SIGCHLD during a sigsuspend. */
5325 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
5326 sigdelset (&suspend_mask, SIGCHLD);
5328 sigemptyset (&blocked_mask);
5332 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
5333 the GNU/Linux Threads library and therefore doesn't really belong
5336 /* Read variable NAME in the target and return its value if found.
5337 Otherwise return zero. It is assumed that the type of the variable
5341 get_signo (const char *name)
5343 struct minimal_symbol *ms;
5346 ms = lookup_minimal_symbol (name, NULL, NULL);
5350 if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
5351 sizeof (signo)) != 0)
5357 /* Return the set of signals used by the threads library in *SET. */
5360 lin_thread_get_thread_signals (sigset_t *set)
5362 struct sigaction action;
5363 int restart, cancel;
5365 sigemptyset (&blocked_mask);
5368 restart = get_signo ("__pthread_sig_restart");
5369 cancel = get_signo ("__pthread_sig_cancel");
5371 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5372 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5373 not provide any way for the debugger to query the signal numbers -
5374 fortunately they don't change! */
5377 restart = __SIGRTMIN;
5380 cancel = __SIGRTMIN + 1;
5382 sigaddset (set, restart);
5383 sigaddset (set, cancel);
5385 /* The GNU/Linux Threads library makes terminating threads send a
5386 special "cancel" signal instead of SIGCHLD. Make sure we catch
5387 those (to prevent them from terminating GDB itself, which is
5388 likely to be their default action) and treat them the same way as
5391 action.sa_handler = sigchld_handler;
5392 sigemptyset (&action.sa_mask);
5393 action.sa_flags = SA_RESTART;
5394 sigaction (cancel, &action, NULL);
5396 /* We block the "cancel" signal throughout this code ... */
5397 sigaddset (&blocked_mask, cancel);
5398 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
5400 /* ... except during a sigsuspend. */
5401 sigdelset (&suspend_mask, cancel);