1 /* GNU/Linux native-dependent code common to multiple platforms.
3 Copyright (C) 2001-2014 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "nat/linux-nat.h"
25 #include "nat/linux-waitpid.h"
27 #ifdef HAVE_TKILL_SYSCALL
29 #include <sys/syscall.h>
31 #include <sys/ptrace.h>
32 #include "linux-nat.h"
33 #include "nat/linux-ptrace.h"
34 #include "nat/linux-procfs.h"
35 #include "linux-fork.h"
36 #include "gdbthread.h"
40 #include "inf-child.h"
41 #include "inf-ptrace.h"
43 #include <sys/procfs.h> /* for elf_gregset etc. */
44 #include "elf-bfd.h" /* for elfcore_write_* */
45 #include "gregset.h" /* for gregset */
46 #include "gdbcore.h" /* for get_exec_file */
47 #include <ctype.h> /* for isdigit */
48 #include <sys/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>
56 #include "xml-support.h"
60 #include "nat/linux-osdata.h"
61 #include "linux-tdep.h"
64 #include "tracepoint.h"
65 #include "exceptions.h"
67 #include "target-descriptions.h"
68 #include "filestuff.h"
72 #define SPUFS_MAGIC 0x23c9b64e
75 #ifdef HAVE_PERSONALITY
76 # include <sys/personality.h>
77 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
78 # define ADDR_NO_RANDOMIZE 0x0040000
80 #endif /* HAVE_PERSONALITY */
82 /* This comment documents high-level logic of this file.
84 Waiting for events in sync mode
85 ===============================
87 When waiting for an event in a specific thread, we just use waitpid, passing
88 the specific pid, and not passing WNOHANG.
90 When waiting for an event in all threads, waitpid is not quite good. Prior to
91 version 2.4, Linux can either wait for event in main thread, or in secondary
92 threads. (2.4 has the __WALL flag). So, if we use blocking waitpid, we might
93 miss an event. The solution is to use non-blocking waitpid, together with
94 sigsuspend. First, we use non-blocking waitpid to get an event in the main
95 process, if any. Second, we use non-blocking waitpid with the __WCLONED
96 flag to check for events in cloned processes. If nothing is found, we use
97 sigsuspend to wait for SIGCHLD. When SIGCHLD arrives, it means something
98 happened to a child process -- and SIGCHLD will be delivered both for events
99 in main debugged process and in cloned processes. As soon as we know there's
100 an event, we get back to calling nonblocking waitpid with and without
103 Note that SIGCHLD should be blocked between waitpid and sigsuspend calls,
104 so that we don't miss a signal. If SIGCHLD arrives in between, when it's
105 blocked, the signal becomes pending and sigsuspend immediately
106 notices it and returns.
108 Waiting for events in async mode
109 ================================
111 In async mode, GDB should always be ready to handle both user input
112 and target events, so neither blocking waitpid nor sigsuspend are
113 viable options. Instead, we should asynchronously notify the GDB main
114 event loop whenever there's an unprocessed event from the target. We
115 detect asynchronous target events by handling SIGCHLD signals. To
116 notify the event loop about target events, the self-pipe trick is used
117 --- a pipe is registered as waitable event source in the event loop,
118 the event loop select/poll's on the read end of this pipe (as well on
119 other event sources, e.g., stdin), and the SIGCHLD handler writes a
120 byte to this pipe. This is more portable than relying on
121 pselect/ppoll, since on kernels that lack those syscalls, libc
122 emulates them with select/poll+sigprocmask, and that is racy
123 (a.k.a. plain broken).
125 Obviously, if we fail to notify the event loop if there's a target
126 event, it's bad. OTOH, if we notify the event loop when there's no
127 event from the target, linux_nat_wait will detect that there's no real
128 event to report, and return event of type TARGET_WAITKIND_IGNORE.
129 This is mostly harmless, but it will waste time and is better avoided.
131 The main design point is that every time GDB is outside linux-nat.c,
132 we have a SIGCHLD handler installed that is called when something
133 happens to the target and notifies the GDB event loop. Whenever GDB
134 core decides to handle the event, and calls into linux-nat.c, we
135 process things as in sync mode, except that the we never block in
138 While processing an event, we may end up momentarily blocked in
139 waitpid calls. Those waitpid calls, while blocking, are guarantied to
140 return quickly. E.g., in all-stop mode, before reporting to the core
141 that an LWP hit a breakpoint, all LWPs are stopped by sending them
142 SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
143 Note that this is different from blocking indefinitely waiting for the
144 next event --- here, we're already handling an event.
149 We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
150 signal is not entirely significant; we just need for a signal to be delivered,
151 so that we can intercept it. SIGSTOP's advantage is that it can not be
152 blocked. A disadvantage is that it is not a real-time signal, so it can only
153 be queued once; we do not keep track of other sources of SIGSTOP.
155 Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
156 use them, because they have special behavior when the signal is generated -
157 not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
158 kills the entire thread group.
160 A delivered SIGSTOP would stop the entire thread group, not just the thread we
161 tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
162 cancel it (by PTRACE_CONT without passing SIGSTOP).
164 We could use a real-time signal instead. This would solve those problems; we
165 could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
166 But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
167 generates it, and there are races with trying to find a signal that is not
171 #define O_LARGEFILE 0
174 /* The single-threaded native GNU/Linux target_ops. We save a pointer for
175 the use of the multi-threaded target. */
176 static struct target_ops *linux_ops;
177 static struct target_ops linux_ops_saved;
179 /* The method to call, if any, when a new thread is attached. */
180 static void (*linux_nat_new_thread) (struct lwp_info *);
182 /* The method to call, if any, when a new fork is attached. */
183 static linux_nat_new_fork_ftype *linux_nat_new_fork;
185 /* The method to call, if any, when a process is no longer
187 static linux_nat_forget_process_ftype *linux_nat_forget_process_hook;
189 /* Hook to call prior to resuming a thread. */
190 static void (*linux_nat_prepare_to_resume) (struct lwp_info *);
192 /* The method to call, if any, when the siginfo object needs to be
193 converted between the layout returned by ptrace, and the layout in
194 the architecture of the inferior. */
195 static int (*linux_nat_siginfo_fixup) (siginfo_t *,
199 /* The saved to_xfer_partial method, inherited from inf-ptrace.c.
200 Called by our to_xfer_partial. */
201 static target_xfer_partial_ftype *super_xfer_partial;
203 /* The saved to_close method, inherited from inf-ptrace.c.
204 Called by our to_close. */
205 static void (*super_close) (struct target_ops *);
207 static unsigned int debug_linux_nat;
209 show_debug_linux_nat (struct ui_file *file, int from_tty,
210 struct cmd_list_element *c, const char *value)
212 fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
216 struct simple_pid_list
220 struct simple_pid_list *next;
222 struct simple_pid_list *stopped_pids;
224 /* Async mode support. */
226 /* The read/write ends of the pipe registered as waitable file in the
228 static int linux_nat_event_pipe[2] = { -1, -1 };
230 /* Flush the event pipe. */
233 async_file_flush (void)
240 ret = read (linux_nat_event_pipe[0], &buf, 1);
242 while (ret >= 0 || (ret == -1 && errno == EINTR));
245 /* Put something (anything, doesn't matter what, or how much) in event
246 pipe, so that the select/poll in the event-loop realizes we have
247 something to process. */
250 async_file_mark (void)
254 /* It doesn't really matter what the pipe contains, as long we end
255 up with something in it. Might as well flush the previous
261 ret = write (linux_nat_event_pipe[1], "+", 1);
263 while (ret == -1 && errno == EINTR);
265 /* Ignore EAGAIN. If the pipe is full, the event loop will already
266 be awakened anyway. */
269 static int kill_lwp (int lwpid, int signo);
271 static int stop_callback (struct lwp_info *lp, void *data);
273 static void block_child_signals (sigset_t *prev_mask);
274 static void restore_child_signals_mask (sigset_t *prev_mask);
277 static struct lwp_info *add_lwp (ptid_t ptid);
278 static void purge_lwp_list (int pid);
279 static void delete_lwp (ptid_t ptid);
280 static struct lwp_info *find_lwp_pid (ptid_t ptid);
283 /* Trivial list manipulation functions to keep track of a list of
284 new stopped processes. */
286 add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
288 struct simple_pid_list *new_pid = xmalloc (sizeof (struct simple_pid_list));
291 new_pid->status = status;
292 new_pid->next = *listp;
297 in_pid_list_p (struct simple_pid_list *list, int pid)
299 struct simple_pid_list *p;
301 for (p = list; p != NULL; p = p->next)
308 pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
310 struct simple_pid_list **p;
312 for (p = listp; *p != NULL; p = &(*p)->next)
313 if ((*p)->pid == pid)
315 struct simple_pid_list *next = (*p)->next;
317 *statusp = (*p)->status;
325 /* Initialize ptrace warnings and check for supported ptrace
326 features given PID. */
329 linux_init_ptrace (pid_t pid)
331 linux_enable_event_reporting (pid);
332 linux_ptrace_init_warnings ();
336 linux_child_post_attach (struct target_ops *self, int pid)
338 linux_init_ptrace (pid);
342 linux_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
344 linux_init_ptrace (ptid_get_pid (ptid));
347 /* Return the number of known LWPs in the tgid given by PID. */
355 for (lp = lwp_list; lp; lp = lp->next)
356 if (ptid_get_pid (lp->ptid) == pid)
362 /* Call delete_lwp with prototype compatible for make_cleanup. */
365 delete_lwp_cleanup (void *lp_voidp)
367 struct lwp_info *lp = lp_voidp;
369 delete_lwp (lp->ptid);
373 linux_child_follow_fork (struct target_ops *ops, int follow_child,
377 int parent_pid, child_pid;
379 has_vforked = (inferior_thread ()->pending_follow.kind
380 == TARGET_WAITKIND_VFORKED);
381 parent_pid = ptid_get_lwp (inferior_ptid);
383 parent_pid = ptid_get_pid (inferior_ptid);
385 = ptid_get_pid (inferior_thread ()->pending_follow.value.related_pid);
388 && !non_stop /* Non-stop always resumes both branches. */
389 && (!target_is_async_p () || sync_execution)
390 && !(follow_child || detach_fork || sched_multi))
392 /* The parent stays blocked inside the vfork syscall until the
393 child execs or exits. If we don't let the child run, then
394 the parent stays blocked. If we're telling the parent to run
395 in the foreground, the user will not be able to ctrl-c to get
396 back the terminal, effectively hanging the debug session. */
397 fprintf_filtered (gdb_stderr, _("\
398 Can not resume the parent process over vfork in the foreground while\n\
399 holding the child stopped. Try \"set detach-on-fork\" or \
400 \"set schedule-multiple\".\n"));
401 /* FIXME output string > 80 columns. */
407 struct lwp_info *child_lp = NULL;
409 /* We're already attached to the parent, by default. */
411 /* Detach new forked process? */
414 struct cleanup *old_chain;
415 int status = W_STOPCODE (0);
417 /* Before detaching from the child, remove all breakpoints
418 from it. If we forked, then this has already been taken
419 care of by infrun.c. If we vforked however, any
420 breakpoint inserted in the parent is visible in the
421 child, even those added while stopped in a vfork
422 catchpoint. This will remove the breakpoints from the
423 parent also, but they'll be reinserted below. */
426 /* keep breakpoints list in sync. */
427 remove_breakpoints_pid (ptid_get_pid (inferior_ptid));
430 if (info_verbose || debug_linux_nat)
432 target_terminal_ours ();
433 fprintf_filtered (gdb_stdlog,
434 "Detaching after fork from "
435 "child process %d.\n",
439 old_chain = save_inferior_ptid ();
440 inferior_ptid = ptid_build (child_pid, child_pid, 0);
442 child_lp = add_lwp (inferior_ptid);
443 child_lp->stopped = 1;
444 child_lp->last_resume_kind = resume_stop;
445 make_cleanup (delete_lwp_cleanup, child_lp);
447 if (linux_nat_prepare_to_resume != NULL)
448 linux_nat_prepare_to_resume (child_lp);
450 /* When debugging an inferior in an architecture that supports
451 hardware single stepping on a kernel without commit
452 6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
453 process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
454 set if the parent process had them set.
455 To work around this, single step the child process
456 once before detaching to clear the flags. */
458 if (!gdbarch_software_single_step_p (target_thread_architecture
461 linux_disable_event_reporting (child_pid);
462 if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
463 perror_with_name (_("Couldn't do single step"));
464 if (my_waitpid (child_pid, &status, 0) < 0)
465 perror_with_name (_("Couldn't wait vfork process"));
468 if (WIFSTOPPED (status))
472 signo = WSTOPSIG (status);
474 && !signal_pass_state (gdb_signal_from_host (signo)))
476 ptrace (PTRACE_DETACH, child_pid, 0, signo);
479 do_cleanups (old_chain);
483 struct inferior *parent_inf, *child_inf;
484 struct cleanup *old_chain;
486 /* Add process to GDB's tables. */
487 child_inf = add_inferior (child_pid);
489 parent_inf = current_inferior ();
490 child_inf->attach_flag = parent_inf->attach_flag;
491 copy_terminal_info (child_inf, parent_inf);
492 child_inf->gdbarch = parent_inf->gdbarch;
493 copy_inferior_target_desc_info (child_inf, parent_inf);
495 old_chain = save_inferior_ptid ();
496 save_current_program_space ();
498 inferior_ptid = ptid_build (child_pid, child_pid, 0);
499 add_thread (inferior_ptid);
500 child_lp = add_lwp (inferior_ptid);
501 child_lp->stopped = 1;
502 child_lp->last_resume_kind = resume_stop;
503 child_inf->symfile_flags = SYMFILE_NO_READ;
505 /* If this is a vfork child, then the address-space is
506 shared with the parent. */
509 child_inf->pspace = parent_inf->pspace;
510 child_inf->aspace = parent_inf->aspace;
512 /* The parent will be frozen until the child is done
513 with the shared region. Keep track of the
515 child_inf->vfork_parent = parent_inf;
516 child_inf->pending_detach = 0;
517 parent_inf->vfork_child = child_inf;
518 parent_inf->pending_detach = 0;
522 child_inf->aspace = new_address_space ();
523 child_inf->pspace = add_program_space (child_inf->aspace);
524 child_inf->removable = 1;
525 set_current_program_space (child_inf->pspace);
526 clone_program_space (child_inf->pspace, parent_inf->pspace);
528 /* Let the shared library layer (solib-svr4) learn about
529 this new process, relocate the cloned exec, pull in
530 shared libraries, and install the solib event
531 breakpoint. If a "cloned-VM" event was propagated
532 better throughout the core, this wouldn't be
534 solib_create_inferior_hook (0);
537 /* Let the thread_db layer learn about this new process. */
538 check_for_thread_db ();
540 do_cleanups (old_chain);
545 struct lwp_info *parent_lp;
546 struct inferior *parent_inf;
548 parent_inf = current_inferior ();
550 /* If we detached from the child, then we have to be careful
551 to not insert breakpoints in the parent until the child
552 is done with the shared memory region. However, if we're
553 staying attached to the child, then we can and should
554 insert breakpoints, so that we can debug it. A
555 subsequent child exec or exit is enough to know when does
556 the child stops using the parent's address space. */
557 parent_inf->waiting_for_vfork_done = detach_fork;
558 parent_inf->pspace->breakpoints_not_allowed = detach_fork;
560 parent_lp = find_lwp_pid (pid_to_ptid (parent_pid));
561 gdb_assert (linux_supports_tracefork () >= 0);
563 if (linux_supports_tracevforkdone ())
566 fprintf_unfiltered (gdb_stdlog,
567 "LCFF: waiting for VFORK_DONE on %d\n",
569 parent_lp->stopped = 1;
571 /* We'll handle the VFORK_DONE event like any other
572 event, in target_wait. */
576 /* We can't insert breakpoints until the child has
577 finished with the shared memory region. We need to
578 wait until that happens. Ideal would be to just
580 - ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
581 - waitpid (parent_pid, &status, __WALL);
582 However, most architectures can't handle a syscall
583 being traced on the way out if it wasn't traced on
586 We might also think to loop, continuing the child
587 until it exits or gets a SIGTRAP. One problem is
588 that the child might call ptrace with PTRACE_TRACEME.
590 There's no simple and reliable way to figure out when
591 the vforked child will be done with its copy of the
592 shared memory. We could step it out of the syscall,
593 two instructions, let it go, and then single-step the
594 parent once. When we have hardware single-step, this
595 would work; with software single-step it could still
596 be made to work but we'd have to be able to insert
597 single-step breakpoints in the child, and we'd have
598 to insert -just- the single-step breakpoint in the
599 parent. Very awkward.
601 In the end, the best we can do is to make sure it
602 runs for a little while. Hopefully it will be out of
603 range of any breakpoints we reinsert. Usually this
604 is only the single-step breakpoint at vfork's return
608 fprintf_unfiltered (gdb_stdlog,
609 "LCFF: no VFORK_DONE "
610 "support, sleeping a bit\n");
614 /* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
615 and leave it pending. The next linux_nat_resume call
616 will notice a pending event, and bypasses actually
617 resuming the inferior. */
618 parent_lp->status = 0;
619 parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
620 parent_lp->stopped = 1;
622 /* If we're in async mode, need to tell the event loop
623 there's something here to process. */
624 if (target_can_async_p ())
631 struct inferior *parent_inf, *child_inf;
632 struct lwp_info *child_lp;
633 struct program_space *parent_pspace;
635 if (info_verbose || debug_linux_nat)
637 target_terminal_ours ();
639 fprintf_filtered (gdb_stdlog,
640 _("Attaching after process %d "
641 "vfork to child process %d.\n"),
642 parent_pid, child_pid);
644 fprintf_filtered (gdb_stdlog,
645 _("Attaching after process %d "
646 "fork to child process %d.\n"),
647 parent_pid, child_pid);
650 /* Add the new inferior first, so that the target_detach below
651 doesn't unpush the target. */
653 child_inf = add_inferior (child_pid);
655 parent_inf = current_inferior ();
656 child_inf->attach_flag = parent_inf->attach_flag;
657 copy_terminal_info (child_inf, parent_inf);
658 child_inf->gdbarch = parent_inf->gdbarch;
659 copy_inferior_target_desc_info (child_inf, parent_inf);
661 parent_pspace = parent_inf->pspace;
663 /* If we're vforking, we want to hold on to the parent until the
664 child exits or execs. At child exec or exit time we can
665 remove the old breakpoints from the parent and detach or
666 resume debugging it. Otherwise, detach the parent now; we'll
667 want to reuse it's program/address spaces, but we can't set
668 them to the child before removing breakpoints from the
669 parent, otherwise, the breakpoints module could decide to
670 remove breakpoints from the wrong process (since they'd be
671 assigned to the same address space). */
675 gdb_assert (child_inf->vfork_parent == NULL);
676 gdb_assert (parent_inf->vfork_child == NULL);
677 child_inf->vfork_parent = parent_inf;
678 child_inf->pending_detach = 0;
679 parent_inf->vfork_child = child_inf;
680 parent_inf->pending_detach = detach_fork;
681 parent_inf->waiting_for_vfork_done = 0;
683 else if (detach_fork)
684 target_detach (NULL, 0);
686 /* Note that the detach above makes PARENT_INF dangling. */
688 /* Add the child thread to the appropriate lists, and switch to
689 this new thread, before cloning the program space, and
690 informing the solib layer about this new process. */
692 inferior_ptid = ptid_build (child_pid, child_pid, 0);
693 add_thread (inferior_ptid);
694 child_lp = add_lwp (inferior_ptid);
695 child_lp->stopped = 1;
696 child_lp->last_resume_kind = resume_stop;
698 /* If this is a vfork child, then the address-space is shared
699 with the parent. If we detached from the parent, then we can
700 reuse the parent's program/address spaces. */
701 if (has_vforked || detach_fork)
703 child_inf->pspace = parent_pspace;
704 child_inf->aspace = child_inf->pspace->aspace;
708 child_inf->aspace = new_address_space ();
709 child_inf->pspace = add_program_space (child_inf->aspace);
710 child_inf->removable = 1;
711 child_inf->symfile_flags = SYMFILE_NO_READ;
712 set_current_program_space (child_inf->pspace);
713 clone_program_space (child_inf->pspace, parent_pspace);
715 /* Let the shared library layer (solib-svr4) learn about
716 this new process, relocate the cloned exec, pull in
717 shared libraries, and install the solib event breakpoint.
718 If a "cloned-VM" event was propagated better throughout
719 the core, this wouldn't be required. */
720 solib_create_inferior_hook (0);
723 /* Let the thread_db layer learn about this new process. */
724 check_for_thread_db ();
732 linux_child_insert_fork_catchpoint (struct target_ops *self, int pid)
734 return !linux_supports_tracefork ();
738 linux_child_remove_fork_catchpoint (struct target_ops *self, int pid)
744 linux_child_insert_vfork_catchpoint (struct target_ops *self, int pid)
746 return !linux_supports_tracefork ();
750 linux_child_remove_vfork_catchpoint (struct target_ops *self, int pid)
756 linux_child_insert_exec_catchpoint (struct target_ops *self, int pid)
758 return !linux_supports_tracefork ();
762 linux_child_remove_exec_catchpoint (struct target_ops *self, int pid)
768 linux_child_set_syscall_catchpoint (struct target_ops *self,
769 int pid, int needed, int any_count,
770 int table_size, int *table)
772 if (!linux_supports_tracesysgood ())
775 /* On GNU/Linux, we ignore the arguments. It means that we only
776 enable the syscall catchpoints, but do not disable them.
778 Also, we do not use the `table' information because we do not
779 filter system calls here. We let GDB do the logic for us. */
783 /* On GNU/Linux there are no real LWP's. The closest thing to LWP's
784 are processes sharing the same VM space. A multi-threaded process
785 is basically a group of such processes. However, such a grouping
786 is almost entirely a user-space issue; the kernel doesn't enforce
787 such a grouping at all (this might change in the future). In
788 general, we'll rely on the threads library (i.e. the GNU/Linux
789 Threads library) to provide such a grouping.
791 It is perfectly well possible to write a multi-threaded application
792 without the assistance of a threads library, by using the clone
793 system call directly. This module should be able to give some
794 rudimentary support for debugging such applications if developers
795 specify the CLONE_PTRACE flag in the clone system call, and are
796 using the Linux kernel 2.4 or above.
798 Note that there are some peculiarities in GNU/Linux that affect
801 - In general one should specify the __WCLONE flag to waitpid in
802 order to make it report events for any of the cloned processes
803 (and leave it out for the initial process). However, if a cloned
804 process has exited the exit status is only reported if the
805 __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
806 we cannot use it since GDB must work on older systems too.
808 - When a traced, cloned process exits and is waited for by the
809 debugger, the kernel reassigns it to the original parent and
810 keeps it around as a "zombie". Somehow, the GNU/Linux Threads
811 library doesn't notice this, which leads to the "zombie problem":
812 When debugged a multi-threaded process that spawns a lot of
813 threads will run out of processes, even if the threads exit,
814 because the "zombies" stay around. */
816 /* List of known LWPs. */
817 struct lwp_info *lwp_list;
820 /* Original signal mask. */
821 static sigset_t normal_mask;
823 /* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
824 _initialize_linux_nat. */
825 static sigset_t suspend_mask;
827 /* Signals to block to make that sigsuspend work. */
828 static sigset_t blocked_mask;
830 /* SIGCHLD action. */
831 struct sigaction sigchld_action;
833 /* Block child signals (SIGCHLD and linux threads signals), and store
834 the previous mask in PREV_MASK. */
837 block_child_signals (sigset_t *prev_mask)
839 /* Make sure SIGCHLD is blocked. */
840 if (!sigismember (&blocked_mask, SIGCHLD))
841 sigaddset (&blocked_mask, SIGCHLD);
843 sigprocmask (SIG_BLOCK, &blocked_mask, prev_mask);
846 /* Restore child signals mask, previously returned by
847 block_child_signals. */
850 restore_child_signals_mask (sigset_t *prev_mask)
852 sigprocmask (SIG_SETMASK, prev_mask, NULL);
855 /* Mask of signals to pass directly to the inferior. */
856 static sigset_t pass_mask;
858 /* Update signals to pass to the inferior. */
860 linux_nat_pass_signals (struct target_ops *self,
861 int numsigs, unsigned char *pass_signals)
865 sigemptyset (&pass_mask);
867 for (signo = 1; signo < NSIG; signo++)
869 int target_signo = gdb_signal_from_host (signo);
870 if (target_signo < numsigs && pass_signals[target_signo])
871 sigaddset (&pass_mask, signo);
877 /* Prototypes for local functions. */
878 static int stop_wait_callback (struct lwp_info *lp, void *data);
879 static int linux_thread_alive (ptid_t ptid);
880 static char *linux_child_pid_to_exec_file (struct target_ops *self, int pid);
884 /* Destroy and free LP. */
887 lwp_free (struct lwp_info *lp)
889 xfree (lp->arch_private);
893 /* Remove all LWPs belong to PID from the lwp list. */
896 purge_lwp_list (int pid)
898 struct lwp_info *lp, *lpprev, *lpnext;
902 for (lp = lwp_list; lp; lp = lpnext)
906 if (ptid_get_pid (lp->ptid) == pid)
911 lpprev->next = lp->next;
920 /* Add the LWP specified by PTID to the list. PTID is the first LWP
921 in the process. Return a pointer to the structure describing the
924 This differs from add_lwp in that we don't let the arch specific
925 bits know about this new thread. Current clients of this callback
926 take the opportunity to install watchpoints in the new thread, and
927 we shouldn't do that for the first thread. If we're spawning a
928 child ("run"), the thread executes the shell wrapper first, and we
929 shouldn't touch it until it execs the program we want to debug.
930 For "attach", it'd be okay to call the callback, but it's not
931 necessary, because watchpoints can't yet have been inserted into
934 static struct lwp_info *
935 add_initial_lwp (ptid_t ptid)
939 gdb_assert (ptid_lwp_p (ptid));
941 lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
943 memset (lp, 0, sizeof (struct lwp_info));
945 lp->last_resume_kind = resume_continue;
946 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
957 /* Add the LWP specified by PID to the list. Return a pointer to the
958 structure describing the new LWP. The LWP should already be
961 static struct lwp_info *
962 add_lwp (ptid_t ptid)
966 lp = add_initial_lwp (ptid);
968 /* Let the arch specific bits know about this new thread. Current
969 clients of this callback take the opportunity to install
970 watchpoints in the new thread. We don't do this for the first
971 thread though. See add_initial_lwp. */
972 if (linux_nat_new_thread != NULL)
973 linux_nat_new_thread (lp);
978 /* Remove the LWP specified by PID from the list. */
981 delete_lwp (ptid_t ptid)
983 struct lwp_info *lp, *lpprev;
987 for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
988 if (ptid_equal (lp->ptid, ptid))
995 lpprev->next = lp->next;
1002 /* Return a pointer to the structure describing the LWP corresponding
1003 to PID. If no corresponding LWP could be found, return NULL. */
1005 static struct lwp_info *
1006 find_lwp_pid (ptid_t ptid)
1008 struct lwp_info *lp;
1011 if (ptid_lwp_p (ptid))
1012 lwp = ptid_get_lwp (ptid);
1014 lwp = ptid_get_pid (ptid);
1016 for (lp = lwp_list; lp; lp = lp->next)
1017 if (lwp == ptid_get_lwp (lp->ptid))
1023 /* Call CALLBACK with its second argument set to DATA for every LWP in
1024 the list. If CALLBACK returns 1 for a particular LWP, return a
1025 pointer to the structure describing that LWP immediately.
1026 Otherwise return NULL. */
1029 iterate_over_lwps (ptid_t filter,
1030 int (*callback) (struct lwp_info *, void *),
1033 struct lwp_info *lp, *lpnext;
1035 for (lp = lwp_list; lp; lp = lpnext)
1039 if (ptid_match (lp->ptid, filter))
1041 if ((*callback) (lp, data))
1049 /* Update our internal state when changing from one checkpoint to
1050 another indicated by NEW_PTID. We can only switch single-threaded
1051 applications, so we only create one new LWP, and the previous list
1055 linux_nat_switch_fork (ptid_t new_ptid)
1057 struct lwp_info *lp;
1059 purge_lwp_list (ptid_get_pid (inferior_ptid));
1061 lp = add_lwp (new_ptid);
1064 /* This changes the thread's ptid while preserving the gdb thread
1065 num. Also changes the inferior pid, while preserving the
1067 thread_change_ptid (inferior_ptid, new_ptid);
1069 /* We've just told GDB core that the thread changed target id, but,
1070 in fact, it really is a different thread, with different register
1072 registers_changed ();
1075 /* Handle the exit of a single thread LP. */
1078 exit_lwp (struct lwp_info *lp)
1080 struct thread_info *th = find_thread_ptid (lp->ptid);
1084 if (print_thread_events)
1085 printf_unfiltered (_("[%s exited]\n"), target_pid_to_str (lp->ptid));
1087 delete_thread (lp->ptid);
1090 delete_lwp (lp->ptid);
1093 /* Wait for the LWP specified by LP, which we have just attached to.
1094 Returns a wait status for that LWP, to cache. */
1097 linux_nat_post_attach_wait (ptid_t ptid, int first, int *cloned,
1100 pid_t new_pid, pid = ptid_get_lwp (ptid);
1103 if (linux_proc_pid_is_stopped (pid))
1105 if (debug_linux_nat)
1106 fprintf_unfiltered (gdb_stdlog,
1107 "LNPAW: Attaching to a stopped process\n");
1109 /* The process is definitely stopped. It is in a job control
1110 stop, unless the kernel predates the TASK_STOPPED /
1111 TASK_TRACED distinction, in which case it might be in a
1112 ptrace stop. Make sure it is in a ptrace stop; from there we
1113 can kill it, signal it, et cetera.
1115 First make sure there is a pending SIGSTOP. Since we are
1116 already attached, the process can not transition from stopped
1117 to running without a PTRACE_CONT; so we know this signal will
1118 go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
1119 probably already in the queue (unless this kernel is old
1120 enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
1121 is not an RT signal, it can only be queued once. */
1122 kill_lwp (pid, SIGSTOP);
1124 /* Finally, resume the stopped process. This will deliver the SIGSTOP
1125 (or a higher priority signal, just like normal PTRACE_ATTACH). */
1126 ptrace (PTRACE_CONT, pid, 0, 0);
1129 /* Make sure the initial process is stopped. The user-level threads
1130 layer might want to poke around in the inferior, and that won't
1131 work if things haven't stabilized yet. */
1132 new_pid = my_waitpid (pid, &status, 0);
1133 if (new_pid == -1 && errno == ECHILD)
1136 warning (_("%s is a cloned process"), target_pid_to_str (ptid));
1138 /* Try again with __WCLONE to check cloned processes. */
1139 new_pid = my_waitpid (pid, &status, __WCLONE);
1143 gdb_assert (pid == new_pid);
1145 if (!WIFSTOPPED (status))
1147 /* The pid we tried to attach has apparently just exited. */
1148 if (debug_linux_nat)
1149 fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
1150 pid, status_to_str (status));
1154 if (WSTOPSIG (status) != SIGSTOP)
1157 if (debug_linux_nat)
1158 fprintf_unfiltered (gdb_stdlog,
1159 "LNPAW: Received %s after attaching\n",
1160 status_to_str (status));
1166 /* Attach to the LWP specified by PID. Return 0 if successful, -1 if
1167 the new LWP could not be attached, or 1 if we're already auto
1168 attached to this thread, but haven't processed the
1169 PTRACE_EVENT_CLONE event of its parent thread, so we just ignore
1170 its existance, without considering it an error. */
1173 lin_lwp_attach_lwp (ptid_t ptid)
1175 struct lwp_info *lp;
1178 gdb_assert (ptid_lwp_p (ptid));
1180 lp = find_lwp_pid (ptid);
1181 lwpid = ptid_get_lwp (ptid);
1183 /* We assume that we're already attached to any LWP that has an id
1184 equal to the overall process id, and to any LWP that is already
1185 in our list of LWPs. If we're not seeing exit events from threads
1186 and we've had PID wraparound since we last tried to stop all threads,
1187 this assumption might be wrong; fortunately, this is very unlikely
1189 if (lwpid != ptid_get_pid (ptid) && lp == NULL)
1191 int status, cloned = 0, signalled = 0;
1193 if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
1195 if (linux_supports_tracefork ())
1197 /* If we haven't stopped all threads when we get here,
1198 we may have seen a thread listed in thread_db's list,
1199 but not processed the PTRACE_EVENT_CLONE yet. If
1200 that's the case, ignore this new thread, and let
1201 normal event handling discover it later. */
1202 if (in_pid_list_p (stopped_pids, lwpid))
1204 /* We've already seen this thread stop, but we
1205 haven't seen the PTRACE_EVENT_CLONE extended
1214 /* See if we've got a stop for this new child
1215 pending. If so, we're already attached. */
1216 new_pid = my_waitpid (lwpid, &status, WNOHANG);
1217 if (new_pid == -1 && errno == ECHILD)
1218 new_pid = my_waitpid (lwpid, &status, __WCLONE | WNOHANG);
1221 if (WIFSTOPPED (status))
1222 add_to_pid_list (&stopped_pids, lwpid, status);
1228 /* If we fail to attach to the thread, issue a warning,
1229 but continue. One way this can happen is if thread
1230 creation is interrupted; as of Linux kernel 2.6.19, a
1231 bug may place threads in the thread list and then fail
1233 warning (_("Can't attach %s: %s"), target_pid_to_str (ptid),
1234 safe_strerror (errno));
1238 if (debug_linux_nat)
1239 fprintf_unfiltered (gdb_stdlog,
1240 "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
1241 target_pid_to_str (ptid));
1243 status = linux_nat_post_attach_wait (ptid, 0, &cloned, &signalled);
1244 if (!WIFSTOPPED (status))
1247 lp = add_lwp (ptid);
1249 lp->cloned = cloned;
1250 lp->signalled = signalled;
1251 if (WSTOPSIG (status) != SIGSTOP)
1254 lp->status = status;
1257 target_post_attach (ptid_get_lwp (lp->ptid));
1259 if (debug_linux_nat)
1261 fprintf_unfiltered (gdb_stdlog,
1262 "LLAL: waitpid %s received %s\n",
1263 target_pid_to_str (ptid),
1264 status_to_str (status));
1269 /* We assume that the LWP representing the original process is
1270 already stopped. Mark it as stopped in the data structure
1271 that the GNU/linux ptrace layer uses to keep track of
1272 threads. Note that this won't have already been done since
1273 the main thread will have, we assume, been stopped by an
1274 attach from a different layer. */
1276 lp = add_lwp (ptid);
1280 lp->last_resume_kind = resume_stop;
1285 linux_nat_create_inferior (struct target_ops *ops,
1286 char *exec_file, char *allargs, char **env,
1289 #ifdef HAVE_PERSONALITY
1290 int personality_orig = 0, personality_set = 0;
1291 #endif /* HAVE_PERSONALITY */
1293 /* The fork_child mechanism is synchronous and calls target_wait, so
1294 we have to mask the async mode. */
1296 #ifdef HAVE_PERSONALITY
1297 if (disable_randomization)
1300 personality_orig = personality (0xffffffff);
1301 if (errno == 0 && !(personality_orig & ADDR_NO_RANDOMIZE))
1303 personality_set = 1;
1304 personality (personality_orig | ADDR_NO_RANDOMIZE);
1306 if (errno != 0 || (personality_set
1307 && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE)))
1308 warning (_("Error disabling address space randomization: %s"),
1309 safe_strerror (errno));
1311 #endif /* HAVE_PERSONALITY */
1313 /* Make sure we report all signals during startup. */
1314 linux_nat_pass_signals (ops, 0, NULL);
1316 linux_ops->to_create_inferior (ops, exec_file, allargs, env, from_tty);
1318 #ifdef HAVE_PERSONALITY
1319 if (personality_set)
1322 personality (personality_orig);
1324 warning (_("Error restoring address space randomization: %s"),
1325 safe_strerror (errno));
1327 #endif /* HAVE_PERSONALITY */
1331 linux_nat_attach (struct target_ops *ops, const char *args, int from_tty)
1333 struct lwp_info *lp;
1336 volatile struct gdb_exception ex;
1338 /* Make sure we report all signals during attach. */
1339 linux_nat_pass_signals (ops, 0, NULL);
1341 TRY_CATCH (ex, RETURN_MASK_ERROR)
1343 linux_ops->to_attach (ops, args, from_tty);
1347 pid_t pid = parse_pid_to_attach (args);
1348 struct buffer buffer;
1349 char *message, *buffer_s;
1351 message = xstrdup (ex.message);
1352 make_cleanup (xfree, message);
1354 buffer_init (&buffer);
1355 linux_ptrace_attach_fail_reason (pid, &buffer);
1357 buffer_grow_str0 (&buffer, "");
1358 buffer_s = buffer_finish (&buffer);
1359 make_cleanup (xfree, buffer_s);
1361 if (*buffer_s != '\0')
1362 throw_error (ex.error, "warning: %s\n%s", buffer_s, message);
1364 throw_error (ex.error, "%s", message);
1367 /* The ptrace base target adds the main thread with (pid,0,0)
1368 format. Decorate it with lwp info. */
1369 ptid = ptid_build (ptid_get_pid (inferior_ptid),
1370 ptid_get_pid (inferior_ptid),
1372 thread_change_ptid (inferior_ptid, ptid);
1374 /* Add the initial process as the first LWP to the list. */
1375 lp = add_initial_lwp (ptid);
1377 status = linux_nat_post_attach_wait (lp->ptid, 1, &lp->cloned,
1379 if (!WIFSTOPPED (status))
1381 if (WIFEXITED (status))
1383 int exit_code = WEXITSTATUS (status);
1385 target_terminal_ours ();
1386 target_mourn_inferior ();
1388 error (_("Unable to attach: program exited normally."));
1390 error (_("Unable to attach: program exited with code %d."),
1393 else if (WIFSIGNALED (status))
1395 enum gdb_signal signo;
1397 target_terminal_ours ();
1398 target_mourn_inferior ();
1400 signo = gdb_signal_from_host (WTERMSIG (status));
1401 error (_("Unable to attach: program terminated with signal "
1403 gdb_signal_to_name (signo),
1404 gdb_signal_to_string (signo));
1407 internal_error (__FILE__, __LINE__,
1408 _("unexpected status %d for PID %ld"),
1409 status, (long) ptid_get_lwp (ptid));
1414 /* Save the wait status to report later. */
1416 if (debug_linux_nat)
1417 fprintf_unfiltered (gdb_stdlog,
1418 "LNA: waitpid %ld, saving status %s\n",
1419 (long) ptid_get_pid (lp->ptid), status_to_str (status));
1421 lp->status = status;
1423 if (target_can_async_p ())
1424 target_async (inferior_event_handler, 0);
1427 /* Get pending status of LP. */
1429 get_pending_status (struct lwp_info *lp, int *status)
1431 enum gdb_signal signo = GDB_SIGNAL_0;
1433 /* If we paused threads momentarily, we may have stored pending
1434 events in lp->status or lp->waitstatus (see stop_wait_callback),
1435 and GDB core hasn't seen any signal for those threads.
1436 Otherwise, the last signal reported to the core is found in the
1437 thread object's stop_signal.
1439 There's a corner case that isn't handled here at present. Only
1440 if the thread stopped with a TARGET_WAITKIND_STOPPED does
1441 stop_signal make sense as a real signal to pass to the inferior.
1442 Some catchpoint related events, like
1443 TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
1444 to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
1445 those traps are debug API (ptrace in our case) related and
1446 induced; the inferior wouldn't see them if it wasn't being
1447 traced. Hence, we should never pass them to the inferior, even
1448 when set to pass state. Since this corner case isn't handled by
1449 infrun.c when proceeding with a signal, for consistency, neither
1450 do we handle it here (or elsewhere in the file we check for
1451 signal pass state). Normally SIGTRAP isn't set to pass state, so
1452 this is really a corner case. */
1454 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1455 signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
1456 else if (lp->status)
1457 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1458 else if (non_stop && !is_executing (lp->ptid))
1460 struct thread_info *tp = find_thread_ptid (lp->ptid);
1462 signo = tp->suspend.stop_signal;
1466 struct target_waitstatus last;
1469 get_last_target_status (&last_ptid, &last);
1471 if (ptid_get_lwp (lp->ptid) == ptid_get_lwp (last_ptid))
1473 struct thread_info *tp = find_thread_ptid (lp->ptid);
1475 signo = tp->suspend.stop_signal;
1481 if (signo == GDB_SIGNAL_0)
1483 if (debug_linux_nat)
1484 fprintf_unfiltered (gdb_stdlog,
1485 "GPT: lwp %s has no pending signal\n",
1486 target_pid_to_str (lp->ptid));
1488 else if (!signal_pass_state (signo))
1490 if (debug_linux_nat)
1491 fprintf_unfiltered (gdb_stdlog,
1492 "GPT: lwp %s had signal %s, "
1493 "but it is in no pass state\n",
1494 target_pid_to_str (lp->ptid),
1495 gdb_signal_to_string (signo));
1499 *status = W_STOPCODE (gdb_signal_to_host (signo));
1501 if (debug_linux_nat)
1502 fprintf_unfiltered (gdb_stdlog,
1503 "GPT: lwp %s has pending signal %s\n",
1504 target_pid_to_str (lp->ptid),
1505 gdb_signal_to_string (signo));
1512 detach_callback (struct lwp_info *lp, void *data)
1514 gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
1516 if (debug_linux_nat && lp->status)
1517 fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
1518 strsignal (WSTOPSIG (lp->status)),
1519 target_pid_to_str (lp->ptid));
1521 /* If there is a pending SIGSTOP, get rid of it. */
1524 if (debug_linux_nat)
1525 fprintf_unfiltered (gdb_stdlog,
1526 "DC: Sending SIGCONT to %s\n",
1527 target_pid_to_str (lp->ptid));
1529 kill_lwp (ptid_get_lwp (lp->ptid), SIGCONT);
1533 /* We don't actually detach from the LWP that has an id equal to the
1534 overall process id just yet. */
1535 if (ptid_get_lwp (lp->ptid) != ptid_get_pid (lp->ptid))
1539 /* Pass on any pending signal for this LWP. */
1540 get_pending_status (lp, &status);
1542 if (linux_nat_prepare_to_resume != NULL)
1543 linux_nat_prepare_to_resume (lp);
1545 if (ptrace (PTRACE_DETACH, ptid_get_lwp (lp->ptid), 0,
1546 WSTOPSIG (status)) < 0)
1547 error (_("Can't detach %s: %s"), target_pid_to_str (lp->ptid),
1548 safe_strerror (errno));
1550 if (debug_linux_nat)
1551 fprintf_unfiltered (gdb_stdlog,
1552 "PTRACE_DETACH (%s, %s, 0) (OK)\n",
1553 target_pid_to_str (lp->ptid),
1554 strsignal (WSTOPSIG (status)));
1556 delete_lwp (lp->ptid);
1563 linux_nat_detach (struct target_ops *ops, const char *args, int from_tty)
1567 struct lwp_info *main_lwp;
1569 pid = ptid_get_pid (inferior_ptid);
1571 /* Don't unregister from the event loop, as there may be other
1572 inferiors running. */
1574 /* Stop all threads before detaching. ptrace requires that the
1575 thread is stopped to sucessfully detach. */
1576 iterate_over_lwps (pid_to_ptid (pid), stop_callback, NULL);
1577 /* ... and wait until all of them have reported back that
1578 they're no longer running. */
1579 iterate_over_lwps (pid_to_ptid (pid), stop_wait_callback, NULL);
1581 iterate_over_lwps (pid_to_ptid (pid), detach_callback, NULL);
1583 /* Only the initial process should be left right now. */
1584 gdb_assert (num_lwps (ptid_get_pid (inferior_ptid)) == 1);
1586 main_lwp = find_lwp_pid (pid_to_ptid (pid));
1588 /* Pass on any pending signal for the last LWP. */
1589 if ((args == NULL || *args == '\0')
1590 && get_pending_status (main_lwp, &status) != -1
1591 && WIFSTOPPED (status))
1595 /* Put the signal number in ARGS so that inf_ptrace_detach will
1596 pass it along with PTRACE_DETACH. */
1598 xsnprintf (tem, 8, "%d", (int) WSTOPSIG (status));
1600 if (debug_linux_nat)
1601 fprintf_unfiltered (gdb_stdlog,
1602 "LND: Sending signal %s to %s\n",
1604 target_pid_to_str (main_lwp->ptid));
1607 if (linux_nat_prepare_to_resume != NULL)
1608 linux_nat_prepare_to_resume (main_lwp);
1609 delete_lwp (main_lwp->ptid);
1611 if (forks_exist_p ())
1613 /* Multi-fork case. The current inferior_ptid is being detached
1614 from, but there are other viable forks to debug. Detach from
1615 the current fork, and context-switch to the first
1617 linux_fork_detach (args, from_tty);
1620 linux_ops->to_detach (ops, args, from_tty);
1626 resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
1630 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
1632 if (inf->vfork_child != NULL)
1634 if (debug_linux_nat)
1635 fprintf_unfiltered (gdb_stdlog,
1636 "RC: Not resuming %s (vfork parent)\n",
1637 target_pid_to_str (lp->ptid));
1639 else if (lp->status == 0
1640 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
1642 if (debug_linux_nat)
1643 fprintf_unfiltered (gdb_stdlog,
1644 "RC: Resuming sibling %s, %s, %s\n",
1645 target_pid_to_str (lp->ptid),
1646 (signo != GDB_SIGNAL_0
1647 ? strsignal (gdb_signal_to_host (signo))
1649 step ? "step" : "resume");
1651 if (linux_nat_prepare_to_resume != NULL)
1652 linux_nat_prepare_to_resume (lp);
1653 linux_ops->to_resume (linux_ops,
1654 pid_to_ptid (ptid_get_lwp (lp->ptid)),
1658 lp->stopped_by_watchpoint = 0;
1662 if (debug_linux_nat)
1663 fprintf_unfiltered (gdb_stdlog,
1664 "RC: Not resuming sibling %s (has pending)\n",
1665 target_pid_to_str (lp->ptid));
1670 if (debug_linux_nat)
1671 fprintf_unfiltered (gdb_stdlog,
1672 "RC: Not resuming sibling %s (not stopped)\n",
1673 target_pid_to_str (lp->ptid));
1677 /* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
1678 Resume LWP with the last stop signal, if it is in pass state. */
1681 linux_nat_resume_callback (struct lwp_info *lp, void *except)
1683 enum gdb_signal signo = GDB_SIGNAL_0;
1690 struct thread_info *thread;
1692 thread = find_thread_ptid (lp->ptid);
1695 signo = thread->suspend.stop_signal;
1696 thread->suspend.stop_signal = GDB_SIGNAL_0;
1700 resume_lwp (lp, 0, signo);
1705 resume_clear_callback (struct lwp_info *lp, void *data)
1708 lp->last_resume_kind = resume_stop;
1713 resume_set_callback (struct lwp_info *lp, void *data)
1716 lp->last_resume_kind = resume_continue;
1721 linux_nat_resume (struct target_ops *ops,
1722 ptid_t ptid, int step, enum gdb_signal signo)
1724 struct lwp_info *lp;
1727 if (debug_linux_nat)
1728 fprintf_unfiltered (gdb_stdlog,
1729 "LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
1730 step ? "step" : "resume",
1731 target_pid_to_str (ptid),
1732 (signo != GDB_SIGNAL_0
1733 ? strsignal (gdb_signal_to_host (signo)) : "0"),
1734 target_pid_to_str (inferior_ptid));
1736 /* A specific PTID means `step only this process id'. */
1737 resume_many = (ptid_equal (minus_one_ptid, ptid)
1738 || ptid_is_pid (ptid));
1740 /* Mark the lwps we're resuming as resumed. */
1741 iterate_over_lwps (ptid, resume_set_callback, NULL);
1743 /* See if it's the current inferior that should be handled
1746 lp = find_lwp_pid (inferior_ptid);
1748 lp = find_lwp_pid (ptid);
1749 gdb_assert (lp != NULL);
1751 /* Remember if we're stepping. */
1753 lp->last_resume_kind = step ? resume_step : resume_continue;
1755 /* If we have a pending wait status for this thread, there is no
1756 point in resuming the process. But first make sure that
1757 linux_nat_wait won't preemptively handle the event - we
1758 should never take this short-circuit if we are going to
1759 leave LP running, since we have skipped resuming all the
1760 other threads. This bit of code needs to be synchronized
1761 with linux_nat_wait. */
1763 if (lp->status && WIFSTOPPED (lp->status))
1766 && WSTOPSIG (lp->status)
1767 && sigismember (&pass_mask, WSTOPSIG (lp->status)))
1769 if (debug_linux_nat)
1770 fprintf_unfiltered (gdb_stdlog,
1771 "LLR: Not short circuiting for ignored "
1772 "status 0x%x\n", lp->status);
1774 /* FIXME: What should we do if we are supposed to continue
1775 this thread with a signal? */
1776 gdb_assert (signo == GDB_SIGNAL_0);
1777 signo = gdb_signal_from_host (WSTOPSIG (lp->status));
1782 if (lp->status || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
1784 /* FIXME: What should we do if we are supposed to continue
1785 this thread with a signal? */
1786 gdb_assert (signo == GDB_SIGNAL_0);
1788 if (debug_linux_nat)
1789 fprintf_unfiltered (gdb_stdlog,
1790 "LLR: Short circuiting for status 0x%x\n",
1793 if (target_can_async_p ())
1795 target_async (inferior_event_handler, 0);
1796 /* Tell the event loop we have something to process. */
1803 iterate_over_lwps (ptid, linux_nat_resume_callback, lp);
1805 /* Convert to something the lower layer understands. */
1806 ptid = pid_to_ptid (ptid_get_lwp (lp->ptid));
1808 if (linux_nat_prepare_to_resume != NULL)
1809 linux_nat_prepare_to_resume (lp);
1810 linux_ops->to_resume (linux_ops, ptid, step, signo);
1811 lp->stopped_by_watchpoint = 0;
1814 if (debug_linux_nat)
1815 fprintf_unfiltered (gdb_stdlog,
1816 "LLR: %s %s, %s (resume event thread)\n",
1817 step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
1818 target_pid_to_str (ptid),
1819 (signo != GDB_SIGNAL_0
1820 ? strsignal (gdb_signal_to_host (signo)) : "0"));
1822 if (target_can_async_p ())
1823 target_async (inferior_event_handler, 0);
1826 /* Send a signal to an LWP. */
1829 kill_lwp (int lwpid, int signo)
1831 /* Use tkill, if possible, in case we are using nptl threads. If tkill
1832 fails, then we are not using nptl threads and we should be using kill. */
1834 #ifdef HAVE_TKILL_SYSCALL
1836 static int tkill_failed;
1843 ret = syscall (__NR_tkill, lwpid, signo);
1844 if (errno != ENOSYS)
1851 return kill (lwpid, signo);
1854 /* Handle a GNU/Linux syscall trap wait response. If we see a syscall
1855 event, check if the core is interested in it: if not, ignore the
1856 event, and keep waiting; otherwise, we need to toggle the LWP's
1857 syscall entry/exit status, since the ptrace event itself doesn't
1858 indicate it, and report the trap to higher layers. */
1861 linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
1863 struct target_waitstatus *ourstatus = &lp->waitstatus;
1864 struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
1865 int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, lp->ptid);
1869 /* If we're stopping threads, there's a SIGSTOP pending, which
1870 makes it so that the LWP reports an immediate syscall return,
1871 followed by the SIGSTOP. Skip seeing that "return" using
1872 PTRACE_CONT directly, and let stop_wait_callback collect the
1873 SIGSTOP. Later when the thread is resumed, a new syscall
1874 entry event. If we didn't do this (and returned 0), we'd
1875 leave a syscall entry pending, and our caller, by using
1876 PTRACE_CONT to collect the SIGSTOP, skips the syscall return
1877 itself. Later, when the user re-resumes this LWP, we'd see
1878 another syscall entry event and we'd mistake it for a return.
1880 If stop_wait_callback didn't force the SIGSTOP out of the LWP
1881 (leaving immediately with LWP->signalled set, without issuing
1882 a PTRACE_CONT), it would still be problematic to leave this
1883 syscall enter pending, as later when the thread is resumed,
1884 it would then see the same syscall exit mentioned above,
1885 followed by the delayed SIGSTOP, while the syscall didn't
1886 actually get to execute. It seems it would be even more
1887 confusing to the user. */
1889 if (debug_linux_nat)
1890 fprintf_unfiltered (gdb_stdlog,
1891 "LHST: ignoring syscall %d "
1892 "for LWP %ld (stopping threads), "
1893 "resuming with PTRACE_CONT for SIGSTOP\n",
1895 ptid_get_lwp (lp->ptid));
1897 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1898 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
1903 if (catch_syscall_enabled ())
1905 /* Always update the entry/return state, even if this particular
1906 syscall isn't interesting to the core now. In async mode,
1907 the user could install a new catchpoint for this syscall
1908 between syscall enter/return, and we'll need to know to
1909 report a syscall return if that happens. */
1910 lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1911 ? TARGET_WAITKIND_SYSCALL_RETURN
1912 : TARGET_WAITKIND_SYSCALL_ENTRY);
1914 if (catching_syscall_number (syscall_number))
1916 /* Alright, an event to report. */
1917 ourstatus->kind = lp->syscall_state;
1918 ourstatus->value.syscall_number = syscall_number;
1920 if (debug_linux_nat)
1921 fprintf_unfiltered (gdb_stdlog,
1922 "LHST: stopping for %s of syscall %d"
1925 == TARGET_WAITKIND_SYSCALL_ENTRY
1926 ? "entry" : "return",
1928 ptid_get_lwp (lp->ptid));
1932 if (debug_linux_nat)
1933 fprintf_unfiltered (gdb_stdlog,
1934 "LHST: ignoring %s of syscall %d "
1936 lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
1937 ? "entry" : "return",
1939 ptid_get_lwp (lp->ptid));
1943 /* If we had been syscall tracing, and hence used PT_SYSCALL
1944 before on this LWP, it could happen that the user removes all
1945 syscall catchpoints before we get to process this event.
1946 There are two noteworthy issues here:
1948 - When stopped at a syscall entry event, resuming with
1949 PT_STEP still resumes executing the syscall and reports a
1952 - Only PT_SYSCALL catches syscall enters. If we last
1953 single-stepped this thread, then this event can't be a
1954 syscall enter. If we last single-stepped this thread, this
1955 has to be a syscall exit.
1957 The points above mean that the next resume, be it PT_STEP or
1958 PT_CONTINUE, can not trigger a syscall trace event. */
1959 if (debug_linux_nat)
1960 fprintf_unfiltered (gdb_stdlog,
1961 "LHST: caught syscall event "
1962 "with no syscall catchpoints."
1963 " %d for LWP %ld, ignoring\n",
1965 ptid_get_lwp (lp->ptid));
1966 lp->syscall_state = TARGET_WAITKIND_IGNORE;
1969 /* The core isn't interested in this event. For efficiency, avoid
1970 stopping all threads only to have the core resume them all again.
1971 Since we're not stopping threads, if we're still syscall tracing
1972 and not stepping, we can't use PTRACE_CONT here, as we'd miss any
1973 subsequent syscall. Simply resume using the inf-ptrace layer,
1974 which knows when to use PT_SYSCALL or PT_CONTINUE. */
1976 /* Note that gdbarch_get_syscall_number may access registers, hence
1978 registers_changed ();
1979 if (linux_nat_prepare_to_resume != NULL)
1980 linux_nat_prepare_to_resume (lp);
1981 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
1982 lp->step, GDB_SIGNAL_0);
1987 /* Handle a GNU/Linux extended wait response. If we see a clone
1988 event, we need to add the new LWP to our list (and not report the
1989 trap to higher layers). This function returns non-zero if the
1990 event should be ignored and we should wait again. If STOPPING is
1991 true, the new LWP remains stopped, otherwise it is continued. */
1994 linux_handle_extended_wait (struct lwp_info *lp, int status,
1997 int pid = ptid_get_lwp (lp->ptid);
1998 struct target_waitstatus *ourstatus = &lp->waitstatus;
1999 int event = status >> 16;
2001 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
2002 || event == PTRACE_EVENT_CLONE)
2004 unsigned long new_pid;
2007 ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
2009 /* If we haven't already seen the new PID stop, wait for it now. */
2010 if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
2012 /* The new child has a pending SIGSTOP. We can't affect it until it
2013 hits the SIGSTOP, but we're already attached. */
2014 ret = my_waitpid (new_pid, &status,
2015 (event == PTRACE_EVENT_CLONE) ? __WCLONE : 0);
2017 perror_with_name (_("waiting for new child"));
2018 else if (ret != new_pid)
2019 internal_error (__FILE__, __LINE__,
2020 _("wait returned unexpected PID %d"), ret);
2021 else if (!WIFSTOPPED (status))
2022 internal_error (__FILE__, __LINE__,
2023 _("wait returned unexpected status 0x%x"), status);
2026 ourstatus->value.related_pid = ptid_build (new_pid, new_pid, 0);
2028 if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
2030 /* The arch-specific native code may need to know about new
2031 forks even if those end up never mapped to an
2033 if (linux_nat_new_fork != NULL)
2034 linux_nat_new_fork (lp, new_pid);
2037 if (event == PTRACE_EVENT_FORK
2038 && linux_fork_checkpointing_p (ptid_get_pid (lp->ptid)))
2040 /* Handle checkpointing by linux-fork.c here as a special
2041 case. We don't want the follow-fork-mode or 'catch fork'
2042 to interfere with this. */
2044 /* This won't actually modify the breakpoint list, but will
2045 physically remove the breakpoints from the child. */
2046 detach_breakpoints (ptid_build (new_pid, new_pid, 0));
2048 /* Retain child fork in ptrace (stopped) state. */
2049 if (!find_fork_pid (new_pid))
2052 /* Report as spurious, so that infrun doesn't want to follow
2053 this fork. We're actually doing an infcall in
2055 ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
2057 /* Report the stop to the core. */
2061 if (event == PTRACE_EVENT_FORK)
2062 ourstatus->kind = TARGET_WAITKIND_FORKED;
2063 else if (event == PTRACE_EVENT_VFORK)
2064 ourstatus->kind = TARGET_WAITKIND_VFORKED;
2067 struct lwp_info *new_lp;
2069 ourstatus->kind = TARGET_WAITKIND_IGNORE;
2071 if (debug_linux_nat)
2072 fprintf_unfiltered (gdb_stdlog,
2073 "LHEW: Got clone event "
2074 "from LWP %d, new child is LWP %ld\n",
2077 new_lp = add_lwp (ptid_build (ptid_get_pid (lp->ptid), new_pid, 0));
2079 new_lp->stopped = 1;
2081 if (WSTOPSIG (status) != SIGSTOP)
2083 /* This can happen if someone starts sending signals to
2084 the new thread before it gets a chance to run, which
2085 have a lower number than SIGSTOP (e.g. SIGUSR1).
2086 This is an unlikely case, and harder to handle for
2087 fork / vfork than for clone, so we do not try - but
2088 we handle it for clone events here. We'll send
2089 the other signal on to the thread below. */
2091 new_lp->signalled = 1;
2095 struct thread_info *tp;
2097 /* When we stop for an event in some other thread, and
2098 pull the thread list just as this thread has cloned,
2099 we'll have seen the new thread in the thread_db list
2100 before handling the CLONE event (glibc's
2101 pthread_create adds the new thread to the thread list
2102 before clone'ing, and has the kernel fill in the
2103 thread's tid on the clone call with
2104 CLONE_PARENT_SETTID). If that happened, and the core
2105 had requested the new thread to stop, we'll have
2106 killed it with SIGSTOP. But since SIGSTOP is not an
2107 RT signal, it can only be queued once. We need to be
2108 careful to not resume the LWP if we wanted it to
2109 stop. In that case, we'll leave the SIGSTOP pending.
2110 It will later be reported as GDB_SIGNAL_0. */
2111 tp = find_thread_ptid (new_lp->ptid);
2112 if (tp != NULL && tp->stop_requested)
2113 new_lp->last_resume_kind = resume_stop;
2120 /* Add the new thread to GDB's lists as soon as possible
2123 1) the frontend doesn't have to wait for a stop to
2126 2) we tag it with the correct running state. */
2128 /* If the thread_db layer is active, let it know about
2129 this new thread, and add it to GDB's list. */
2130 if (!thread_db_attach_lwp (new_lp->ptid))
2132 /* We're not using thread_db. Add it to GDB's
2134 target_post_attach (ptid_get_lwp (new_lp->ptid));
2135 add_thread (new_lp->ptid);
2140 set_running (new_lp->ptid, 1);
2141 set_executing (new_lp->ptid, 1);
2142 /* thread_db_attach_lwp -> lin_lwp_attach_lwp forced
2144 new_lp->last_resume_kind = resume_continue;
2150 /* We created NEW_LP so it cannot yet contain STATUS. */
2151 gdb_assert (new_lp->status == 0);
2153 /* Save the wait status to report later. */
2154 if (debug_linux_nat)
2155 fprintf_unfiltered (gdb_stdlog,
2156 "LHEW: waitpid of new LWP %ld, "
2157 "saving status %s\n",
2158 (long) ptid_get_lwp (new_lp->ptid),
2159 status_to_str (status));
2160 new_lp->status = status;
2163 /* Note the need to use the low target ops to resume, to
2164 handle resuming with PT_SYSCALL if we have syscall
2168 new_lp->resumed = 1;
2172 gdb_assert (new_lp->last_resume_kind == resume_continue);
2173 if (debug_linux_nat)
2174 fprintf_unfiltered (gdb_stdlog,
2175 "LHEW: resuming new LWP %ld\n",
2176 ptid_get_lwp (new_lp->ptid));
2177 if (linux_nat_prepare_to_resume != NULL)
2178 linux_nat_prepare_to_resume (new_lp);
2179 linux_ops->to_resume (linux_ops, pid_to_ptid (new_pid),
2181 new_lp->stopped = 0;
2185 if (debug_linux_nat)
2186 fprintf_unfiltered (gdb_stdlog,
2187 "LHEW: resuming parent LWP %d\n", pid);
2188 if (linux_nat_prepare_to_resume != NULL)
2189 linux_nat_prepare_to_resume (lp);
2190 linux_ops->to_resume (linux_ops,
2191 pid_to_ptid (ptid_get_lwp (lp->ptid)),
2200 if (event == PTRACE_EVENT_EXEC)
2202 if (debug_linux_nat)
2203 fprintf_unfiltered (gdb_stdlog,
2204 "LHEW: Got exec event from LWP %ld\n",
2205 ptid_get_lwp (lp->ptid));
2207 ourstatus->kind = TARGET_WAITKIND_EXECD;
2208 ourstatus->value.execd_pathname
2209 = xstrdup (linux_child_pid_to_exec_file (NULL, pid));
2214 if (event == PTRACE_EVENT_VFORK_DONE)
2216 if (current_inferior ()->waiting_for_vfork_done)
2218 if (debug_linux_nat)
2219 fprintf_unfiltered (gdb_stdlog,
2220 "LHEW: Got expected PTRACE_EVENT_"
2221 "VFORK_DONE from LWP %ld: stopping\n",
2222 ptid_get_lwp (lp->ptid));
2224 ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
2228 if (debug_linux_nat)
2229 fprintf_unfiltered (gdb_stdlog,
2230 "LHEW: Got PTRACE_EVENT_VFORK_DONE "
2231 "from LWP %ld: resuming\n",
2232 ptid_get_lwp (lp->ptid));
2233 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2237 internal_error (__FILE__, __LINE__,
2238 _("unknown ptrace event %d"), event);
2241 /* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
2245 wait_lwp (struct lwp_info *lp)
2249 int thread_dead = 0;
2252 gdb_assert (!lp->stopped);
2253 gdb_assert (lp->status == 0);
2255 /* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
2256 block_child_signals (&prev_mask);
2260 /* If my_waitpid returns 0 it means the __WCLONE vs. non-__WCLONE kind
2261 was right and we should just call sigsuspend. */
2263 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, WNOHANG);
2264 if (pid == -1 && errno == ECHILD)
2265 pid = my_waitpid (ptid_get_lwp (lp->ptid), &status, __WCLONE | WNOHANG);
2266 if (pid == -1 && errno == ECHILD)
2268 /* The thread has previously exited. We need to delete it
2269 now because, for some vendor 2.4 kernels with NPTL
2270 support backported, there won't be an exit event unless
2271 it is the main thread. 2.6 kernels will report an exit
2272 event for each thread that exits, as expected. */
2274 if (debug_linux_nat)
2275 fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
2276 target_pid_to_str (lp->ptid));
2281 /* Bugs 10970, 12702.
2282 Thread group leader may have exited in which case we'll lock up in
2283 waitpid if there are other threads, even if they are all zombies too.
2284 Basically, we're not supposed to use waitpid this way.
2285 __WCLONE is not applicable for the leader so we can't use that.
2286 LINUX_NAT_THREAD_ALIVE cannot be used here as it requires a STOPPED
2287 process; it gets ESRCH both for the zombie and for running processes.
2289 As a workaround, check if we're waiting for the thread group leader and
2290 if it's a zombie, and avoid calling waitpid if it is.
2292 This is racy, what if the tgl becomes a zombie right after we check?
2293 Therefore always use WNOHANG with sigsuspend - it is equivalent to
2294 waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
2296 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)
2297 && linux_proc_pid_is_zombie (ptid_get_lwp (lp->ptid)))
2300 if (debug_linux_nat)
2301 fprintf_unfiltered (gdb_stdlog,
2302 "WL: Thread group leader %s vanished.\n",
2303 target_pid_to_str (lp->ptid));
2307 /* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
2308 get invoked despite our caller had them intentionally blocked by
2309 block_child_signals. This is sensitive only to the loop of
2310 linux_nat_wait_1 and there if we get called my_waitpid gets called
2311 again before it gets to sigsuspend so we can safely let the handlers
2312 get executed here. */
2314 if (debug_linux_nat)
2315 fprintf_unfiltered (gdb_stdlog, "WL: about to sigsuspend\n");
2316 sigsuspend (&suspend_mask);
2319 restore_child_signals_mask (&prev_mask);
2323 gdb_assert (pid == ptid_get_lwp (lp->ptid));
2325 if (debug_linux_nat)
2327 fprintf_unfiltered (gdb_stdlog,
2328 "WL: waitpid %s received %s\n",
2329 target_pid_to_str (lp->ptid),
2330 status_to_str (status));
2333 /* Check if the thread has exited. */
2334 if (WIFEXITED (status) || WIFSIGNALED (status))
2337 if (debug_linux_nat)
2338 fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
2339 target_pid_to_str (lp->ptid));
2349 gdb_assert (WIFSTOPPED (status));
2352 /* Handle GNU/Linux's syscall SIGTRAPs. */
2353 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2355 /* No longer need the sysgood bit. The ptrace event ends up
2356 recorded in lp->waitstatus if we care for it. We can carry
2357 on handling the event like a regular SIGTRAP from here
2359 status = W_STOPCODE (SIGTRAP);
2360 if (linux_handle_syscall_trap (lp, 1))
2361 return wait_lwp (lp);
2364 /* Handle GNU/Linux's extended waitstatus for trace events. */
2365 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2367 if (debug_linux_nat)
2368 fprintf_unfiltered (gdb_stdlog,
2369 "WL: Handling extended status 0x%06x\n",
2371 if (linux_handle_extended_wait (lp, status, 1))
2372 return wait_lwp (lp);
2378 /* Send a SIGSTOP to LP. */
2381 stop_callback (struct lwp_info *lp, void *data)
2383 if (!lp->stopped && !lp->signalled)
2387 if (debug_linux_nat)
2389 fprintf_unfiltered (gdb_stdlog,
2390 "SC: kill %s **<SIGSTOP>**\n",
2391 target_pid_to_str (lp->ptid));
2394 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2395 if (debug_linux_nat)
2397 fprintf_unfiltered (gdb_stdlog,
2398 "SC: lwp kill %d %s\n",
2400 errno ? safe_strerror (errno) : "ERRNO-OK");
2404 gdb_assert (lp->status == 0);
2410 /* Request a stop on LWP. */
2413 linux_stop_lwp (struct lwp_info *lwp)
2415 stop_callback (lwp, NULL);
2418 /* Return non-zero if LWP PID has a pending SIGINT. */
2421 linux_nat_has_pending_sigint (int pid)
2423 sigset_t pending, blocked, ignored;
2425 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2427 if (sigismember (&pending, SIGINT)
2428 && !sigismember (&ignored, SIGINT))
2434 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2437 set_ignore_sigint (struct lwp_info *lp, void *data)
2439 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2440 flag to consume the next one. */
2441 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2442 && WSTOPSIG (lp->status) == SIGINT)
2445 lp->ignore_sigint = 1;
2450 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2451 This function is called after we know the LWP has stopped; if the LWP
2452 stopped before the expected SIGINT was delivered, then it will never have
2453 arrived. Also, if the signal was delivered to a shared queue and consumed
2454 by a different thread, it will never be delivered to this LWP. */
2457 maybe_clear_ignore_sigint (struct lwp_info *lp)
2459 if (!lp->ignore_sigint)
2462 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2464 if (debug_linux_nat)
2465 fprintf_unfiltered (gdb_stdlog,
2466 "MCIS: Clearing bogus flag for %s\n",
2467 target_pid_to_str (lp->ptid));
2468 lp->ignore_sigint = 0;
2472 /* Fetch the possible triggered data watchpoint info and store it in
2475 On some archs, like x86, that use debug registers to set
2476 watchpoints, it's possible that the way to know which watched
2477 address trapped, is to check the register that is used to select
2478 which address to watch. Problem is, between setting the watchpoint
2479 and reading back which data address trapped, the user may change
2480 the set of watchpoints, and, as a consequence, GDB changes the
2481 debug registers in the inferior. To avoid reading back a stale
2482 stopped-data-address when that happens, we cache in LP the fact
2483 that a watchpoint trapped, and the corresponding data address, as
2484 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2485 registers meanwhile, we have the cached data we can rely on. */
2488 save_sigtrap (struct lwp_info *lp)
2490 struct cleanup *old_chain;
2492 if (linux_ops->to_stopped_by_watchpoint == NULL)
2494 lp->stopped_by_watchpoint = 0;
2498 old_chain = save_inferior_ptid ();
2499 inferior_ptid = lp->ptid;
2501 lp->stopped_by_watchpoint = linux_ops->to_stopped_by_watchpoint (linux_ops);
2503 if (lp->stopped_by_watchpoint)
2505 if (linux_ops->to_stopped_data_address != NULL)
2506 lp->stopped_data_address_p =
2507 linux_ops->to_stopped_data_address (¤t_target,
2508 &lp->stopped_data_address);
2510 lp->stopped_data_address_p = 0;
2513 do_cleanups (old_chain);
2516 /* See save_sigtrap. */
2519 linux_nat_stopped_by_watchpoint (struct target_ops *ops)
2521 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2523 gdb_assert (lp != NULL);
2525 return lp->stopped_by_watchpoint;
2529 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2531 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2533 gdb_assert (lp != NULL);
2535 *addr_p = lp->stopped_data_address;
2537 return lp->stopped_data_address_p;
2540 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2543 sigtrap_is_event (int status)
2545 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2548 /* SIGTRAP-like events recognizer. */
2550 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
2552 /* Check for SIGTRAP-like events in LP. */
2555 linux_nat_lp_status_is_event (struct lwp_info *lp)
2557 /* We check for lp->waitstatus in addition to lp->status, because we can
2558 have pending process exits recorded in lp->status
2559 and W_EXITCODE(0,0) == 0. We should probably have an additional
2560 lp->status_p flag. */
2562 return (lp->waitstatus.kind == TARGET_WAITKIND_IGNORE
2563 && linux_nat_status_is_event (lp->status));
2566 /* Set alternative SIGTRAP-like events recognizer. If
2567 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2571 linux_nat_set_status_is_event (struct target_ops *t,
2572 int (*status_is_event) (int status))
2574 linux_nat_status_is_event = status_is_event;
2577 /* Wait until LP is stopped. */
2580 stop_wait_callback (struct lwp_info *lp, void *data)
2582 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2584 /* If this is a vfork parent, bail out, it is not going to report
2585 any SIGSTOP until the vfork is done with. */
2586 if (inf->vfork_child != NULL)
2593 status = wait_lwp (lp);
2597 if (lp->ignore_sigint && WIFSTOPPED (status)
2598 && WSTOPSIG (status) == SIGINT)
2600 lp->ignore_sigint = 0;
2603 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2605 if (debug_linux_nat)
2606 fprintf_unfiltered (gdb_stdlog,
2607 "PTRACE_CONT %s, 0, 0 (%s) "
2608 "(discarding SIGINT)\n",
2609 target_pid_to_str (lp->ptid),
2610 errno ? safe_strerror (errno) : "OK");
2612 return stop_wait_callback (lp, NULL);
2615 maybe_clear_ignore_sigint (lp);
2617 if (WSTOPSIG (status) != SIGSTOP)
2619 /* The thread was stopped with a signal other than SIGSTOP. */
2623 if (debug_linux_nat)
2624 fprintf_unfiltered (gdb_stdlog,
2625 "SWC: Pending event %s in %s\n",
2626 status_to_str ((int) status),
2627 target_pid_to_str (lp->ptid));
2629 /* Save the sigtrap event. */
2630 lp->status = status;
2631 gdb_assert (lp->signalled);
2635 /* We caught the SIGSTOP that we intended to catch, so
2636 there's no SIGSTOP pending. */
2638 if (debug_linux_nat)
2639 fprintf_unfiltered (gdb_stdlog,
2640 "SWC: Delayed SIGSTOP caught for %s.\n",
2641 target_pid_to_str (lp->ptid));
2643 /* Reset SIGNALLED only after the stop_wait_callback call
2644 above as it does gdb_assert on SIGNALLED. */
2652 /* Return non-zero if LP has a wait status pending. */
2655 status_callback (struct lwp_info *lp, void *data)
2657 /* Only report a pending wait status if we pretend that this has
2658 indeed been resumed. */
2662 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2664 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2665 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2666 0', so a clean process exit can not be stored pending in
2667 lp->status, it is indistinguishable from
2668 no-pending-status. */
2672 if (lp->status != 0)
2678 /* Return non-zero if LP isn't stopped. */
2681 running_callback (struct lwp_info *lp, void *data)
2683 return (!lp->stopped
2684 || ((lp->status != 0
2685 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2689 /* Count the LWP's that have had events. */
2692 count_events_callback (struct lwp_info *lp, void *data)
2696 gdb_assert (count != NULL);
2698 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2699 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2705 /* Select the LWP (if any) that is currently being single-stepped. */
2708 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2710 if (lp->last_resume_kind == resume_step
2717 /* Select the Nth LWP that has had a SIGTRAP event. */
2720 select_event_lwp_callback (struct lwp_info *lp, void *data)
2722 int *selector = data;
2724 gdb_assert (selector != NULL);
2726 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2727 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2728 if ((*selector)-- == 0)
2735 cancel_breakpoint (struct lwp_info *lp)
2737 /* Arrange for a breakpoint to be hit again later. We don't keep
2738 the SIGTRAP status and don't forward the SIGTRAP signal to the
2739 LWP. We will handle the current event, eventually we will resume
2740 this LWP, and this breakpoint will trap again.
2742 If we do not do this, then we run the risk that the user will
2743 delete or disable the breakpoint, but the LWP will have already
2746 struct regcache *regcache = get_thread_regcache (lp->ptid);
2747 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2750 pc = regcache_read_pc (regcache) - target_decr_pc_after_break (gdbarch);
2751 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2753 if (debug_linux_nat)
2754 fprintf_unfiltered (gdb_stdlog,
2755 "CB: Push back breakpoint for %s\n",
2756 target_pid_to_str (lp->ptid));
2758 /* Back up the PC if necessary. */
2759 if (target_decr_pc_after_break (gdbarch))
2760 regcache_write_pc (regcache, pc);
2768 cancel_breakpoints_callback (struct lwp_info *lp, void *data)
2770 struct lwp_info *event_lp = data;
2772 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2776 /* If a LWP other than the LWP that we're reporting an event for has
2777 hit a GDB breakpoint (as opposed to some random trap signal),
2778 then just arrange for it to hit it again later. We don't keep
2779 the SIGTRAP status and don't forward the SIGTRAP signal to the
2780 LWP. We will handle the current event, eventually we will resume
2781 all LWPs, and this one will get its breakpoint trap again.
2783 If we do not do this, then we run the risk that the user will
2784 delete or disable the breakpoint, but the LWP will have already
2787 if (linux_nat_lp_status_is_event (lp)
2788 && cancel_breakpoint (lp))
2789 /* Throw away the SIGTRAP. */
2795 /* Select one LWP out of those that have events pending. */
2798 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2801 int random_selector;
2802 struct lwp_info *event_lp;
2804 /* Record the wait status for the original LWP. */
2805 (*orig_lp)->status = *status;
2807 /* Give preference to any LWP that is being single-stepped. */
2808 event_lp = iterate_over_lwps (filter,
2809 select_singlestep_lwp_callback, NULL);
2810 if (event_lp != NULL)
2812 if (debug_linux_nat)
2813 fprintf_unfiltered (gdb_stdlog,
2814 "SEL: Select single-step %s\n",
2815 target_pid_to_str (event_lp->ptid));
2819 /* No single-stepping LWP. Select one at random, out of those
2820 which have had SIGTRAP events. */
2822 /* First see how many SIGTRAP events we have. */
2823 iterate_over_lwps (filter, count_events_callback, &num_events);
2825 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2826 random_selector = (int)
2827 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2829 if (debug_linux_nat && num_events > 1)
2830 fprintf_unfiltered (gdb_stdlog,
2831 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2832 num_events, random_selector);
2834 event_lp = iterate_over_lwps (filter,
2835 select_event_lwp_callback,
2839 if (event_lp != NULL)
2841 /* Switch the event LWP. */
2842 *orig_lp = event_lp;
2843 *status = event_lp->status;
2846 /* Flush the wait status for the event LWP. */
2847 (*orig_lp)->status = 0;
2850 /* Return non-zero if LP has been resumed. */
2853 resumed_callback (struct lwp_info *lp, void *data)
2858 /* Stop an active thread, verify it still exists, then resume it. If
2859 the thread ends up with a pending status, then it is not resumed,
2860 and *DATA (really a pointer to int), is set. */
2863 stop_and_resume_callback (struct lwp_info *lp, void *data)
2865 int *new_pending_p = data;
2869 ptid_t ptid = lp->ptid;
2871 stop_callback (lp, NULL);
2872 stop_wait_callback (lp, NULL);
2874 /* Resume if the lwp still exists, and the core wanted it
2876 lp = find_lwp_pid (ptid);
2879 if (lp->last_resume_kind == resume_stop
2882 /* The core wanted the LWP to stop. Even if it stopped
2883 cleanly (with SIGSTOP), leave the event pending. */
2884 if (debug_linux_nat)
2885 fprintf_unfiltered (gdb_stdlog,
2886 "SARC: core wanted LWP %ld stopped "
2887 "(leaving SIGSTOP pending)\n",
2888 ptid_get_lwp (lp->ptid));
2889 lp->status = W_STOPCODE (SIGSTOP);
2892 if (lp->status == 0)
2894 if (debug_linux_nat)
2895 fprintf_unfiltered (gdb_stdlog,
2896 "SARC: re-resuming LWP %ld\n",
2897 ptid_get_lwp (lp->ptid));
2898 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
2902 if (debug_linux_nat)
2903 fprintf_unfiltered (gdb_stdlog,
2904 "SARC: not re-resuming LWP %ld "
2906 ptid_get_lwp (lp->ptid));
2915 /* Check if we should go on and pass this event to common code.
2916 Return the affected lwp if we are, or NULL otherwise. If we stop
2917 all lwps temporarily, we may end up with new pending events in some
2918 other lwp. In that case set *NEW_PENDING_P to true. */
2920 static struct lwp_info *
2921 linux_nat_filter_event (int lwpid, int status, int *new_pending_p)
2923 struct lwp_info *lp;
2927 lp = find_lwp_pid (pid_to_ptid (lwpid));
2929 /* Check for stop events reported by a process we didn't already
2930 know about - anything not already in our LWP list.
2932 If we're expecting to receive stopped processes after
2933 fork, vfork, and clone events, then we'll just add the
2934 new one to our list and go back to waiting for the event
2935 to be reported - the stopped process might be returned
2936 from waitpid before or after the event is.
2938 But note the case of a non-leader thread exec'ing after the
2939 leader having exited, and gone from our lists. The non-leader
2940 thread changes its tid to the tgid. */
2942 if (WIFSTOPPED (status) && lp == NULL
2943 && (WSTOPSIG (status) == SIGTRAP && status >> 16 == PTRACE_EVENT_EXEC))
2945 /* A multi-thread exec after we had seen the leader exiting. */
2946 if (debug_linux_nat)
2947 fprintf_unfiltered (gdb_stdlog,
2948 "LLW: Re-adding thread group leader LWP %d.\n",
2951 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
2954 add_thread (lp->ptid);
2957 if (WIFSTOPPED (status) && !lp)
2959 add_to_pid_list (&stopped_pids, lwpid, status);
2963 /* Make sure we don't report an event for the exit of an LWP not in
2964 our list, i.e. not part of the current process. This can happen
2965 if we detach from a program we originally forked and then it
2967 if (!WIFSTOPPED (status) && !lp)
2970 /* This LWP is stopped now. (And if dead, this prevents it from
2971 ever being continued.) */
2974 /* Handle GNU/Linux's syscall SIGTRAPs. */
2975 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2977 /* No longer need the sysgood bit. The ptrace event ends up
2978 recorded in lp->waitstatus if we care for it. We can carry
2979 on handling the event like a regular SIGTRAP from here
2981 status = W_STOPCODE (SIGTRAP);
2982 if (linux_handle_syscall_trap (lp, 0))
2986 /* Handle GNU/Linux's extended waitstatus for trace events. */
2987 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
2989 if (debug_linux_nat)
2990 fprintf_unfiltered (gdb_stdlog,
2991 "LLW: Handling extended status 0x%06x\n",
2993 if (linux_handle_extended_wait (lp, status, 0))
2997 if (linux_nat_status_is_event (status))
3000 /* Check if the thread has exited. */
3001 if ((WIFEXITED (status) || WIFSIGNALED (status))
3002 && num_lwps (ptid_get_pid (lp->ptid)) > 1)
3004 /* If this is the main thread, we must stop all threads and verify
3005 if they are still alive. This is because in the nptl thread model
3006 on Linux 2.4, there is no signal issued for exiting LWPs
3007 other than the main thread. We only get the main thread exit
3008 signal once all child threads have already exited. If we
3009 stop all the threads and use the stop_wait_callback to check
3010 if they have exited we can determine whether this signal
3011 should be ignored or whether it means the end of the debugged
3012 application, regardless of which threading model is being
3014 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
3016 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3017 stop_and_resume_callback, new_pending_p);
3020 if (debug_linux_nat)
3021 fprintf_unfiltered (gdb_stdlog,
3022 "LLW: %s exited.\n",
3023 target_pid_to_str (lp->ptid));
3025 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3027 /* If there is at least one more LWP, then the exit signal
3028 was not the end of the debugged application and should be
3035 /* Check if the current LWP has previously exited. In the nptl
3036 thread model, LWPs other than the main thread do not issue
3037 signals when they exit so we must check whenever the thread has
3038 stopped. A similar check is made in stop_wait_callback(). */
3039 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3041 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
3043 if (debug_linux_nat)
3044 fprintf_unfiltered (gdb_stdlog,
3045 "LLW: %s exited.\n",
3046 target_pid_to_str (lp->ptid));
3050 /* Make sure there is at least one thread running. */
3051 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3053 /* Discard the event. */
3057 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3058 an attempt to stop an LWP. */
3060 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3062 if (debug_linux_nat)
3063 fprintf_unfiltered (gdb_stdlog,
3064 "LLW: Delayed SIGSTOP caught for %s.\n",
3065 target_pid_to_str (lp->ptid));
3069 if (lp->last_resume_kind != resume_stop)
3071 /* This is a delayed SIGSTOP. */
3073 registers_changed ();
3075 if (linux_nat_prepare_to_resume != NULL)
3076 linux_nat_prepare_to_resume (lp);
3077 linux_ops->to_resume (linux_ops,
3078 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3079 lp->step, GDB_SIGNAL_0);
3080 if (debug_linux_nat)
3081 fprintf_unfiltered (gdb_stdlog,
3082 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3084 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3085 target_pid_to_str (lp->ptid));
3088 gdb_assert (lp->resumed);
3090 /* Discard the event. */
3095 /* Make sure we don't report a SIGINT that we have already displayed
3096 for another thread. */
3097 if (lp->ignore_sigint
3098 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3100 if (debug_linux_nat)
3101 fprintf_unfiltered (gdb_stdlog,
3102 "LLW: Delayed SIGINT caught for %s.\n",
3103 target_pid_to_str (lp->ptid));
3105 /* This is a delayed SIGINT. */
3106 lp->ignore_sigint = 0;
3108 registers_changed ();
3109 if (linux_nat_prepare_to_resume != NULL)
3110 linux_nat_prepare_to_resume (lp);
3111 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3112 lp->step, GDB_SIGNAL_0);
3113 if (debug_linux_nat)
3114 fprintf_unfiltered (gdb_stdlog,
3115 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3117 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3118 target_pid_to_str (lp->ptid));
3121 gdb_assert (lp->resumed);
3123 /* Discard the event. */
3127 /* An interesting event. */
3129 lp->status = status;
3133 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3134 their exits until all other threads in the group have exited. */
3137 check_zombie_leaders (void)
3139 struct inferior *inf;
3143 struct lwp_info *leader_lp;
3148 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3149 if (leader_lp != NULL
3150 /* Check if there are other threads in the group, as we may
3151 have raced with the inferior simply exiting. */
3152 && num_lwps (inf->pid) > 1
3153 && linux_proc_pid_is_zombie (inf->pid))
3155 if (debug_linux_nat)
3156 fprintf_unfiltered (gdb_stdlog,
3157 "CZL: Thread group leader %d zombie "
3158 "(it exited, or another thread execd).\n",
3161 /* A leader zombie can mean one of two things:
3163 - It exited, and there's an exit status pending
3164 available, or only the leader exited (not the whole
3165 program). In the latter case, we can't waitpid the
3166 leader's exit status until all other threads are gone.
3168 - There are 3 or more threads in the group, and a thread
3169 other than the leader exec'd. On an exec, the Linux
3170 kernel destroys all other threads (except the execing
3171 one) in the thread group, and resets the execing thread's
3172 tid to the tgid. No exit notification is sent for the
3173 execing thread -- from the ptracer's perspective, it
3174 appears as though the execing thread just vanishes.
3175 Until we reap all other threads except the leader and the
3176 execing thread, the leader will be zombie, and the
3177 execing thread will be in `D (disc sleep)'. As soon as
3178 all other threads are reaped, the execing thread changes
3179 it's tid to the tgid, and the previous (zombie) leader
3180 vanishes, giving place to the "new" leader. We could try
3181 distinguishing the exit and exec cases, by waiting once
3182 more, and seeing if something comes out, but it doesn't
3183 sound useful. The previous leader _does_ go away, and
3184 we'll re-add the new one once we see the exec event
3185 (which is just the same as what would happen if the
3186 previous leader did exit voluntarily before some other
3189 if (debug_linux_nat)
3190 fprintf_unfiltered (gdb_stdlog,
3191 "CZL: Thread group leader %d vanished.\n",
3193 exit_lwp (leader_lp);
3199 linux_nat_wait_1 (struct target_ops *ops,
3200 ptid_t ptid, struct target_waitstatus *ourstatus,
3203 static sigset_t prev_mask;
3204 enum resume_kind last_resume_kind;
3205 struct lwp_info *lp;
3208 if (debug_linux_nat)
3209 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3211 /* The first time we get here after starting a new inferior, we may
3212 not have added it to the LWP list yet - this is the earliest
3213 moment at which we know its PID. */
3214 if (ptid_is_pid (inferior_ptid))
3216 /* Upgrade the main thread's ptid. */
3217 thread_change_ptid (inferior_ptid,
3218 ptid_build (ptid_get_pid (inferior_ptid),
3219 ptid_get_pid (inferior_ptid), 0));
3221 lp = add_initial_lwp (inferior_ptid);
3225 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3226 block_child_signals (&prev_mask);
3232 /* First check if there is a LWP with a wait status pending. */
3233 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3235 /* Any LWP in the PTID group that's been resumed will do. */
3236 lp = iterate_over_lwps (ptid, status_callback, NULL);
3239 if (debug_linux_nat && lp->status)
3240 fprintf_unfiltered (gdb_stdlog,
3241 "LLW: Using pending wait status %s for %s.\n",
3242 status_to_str (lp->status),
3243 target_pid_to_str (lp->ptid));
3246 else if (ptid_lwp_p (ptid))
3248 if (debug_linux_nat)
3249 fprintf_unfiltered (gdb_stdlog,
3250 "LLW: Waiting for specific LWP %s.\n",
3251 target_pid_to_str (ptid));
3253 /* We have a specific LWP to check. */
3254 lp = find_lwp_pid (ptid);
3257 if (debug_linux_nat && lp->status)
3258 fprintf_unfiltered (gdb_stdlog,
3259 "LLW: Using pending wait status %s for %s.\n",
3260 status_to_str (lp->status),
3261 target_pid_to_str (lp->ptid));
3263 /* We check for lp->waitstatus in addition to lp->status,
3264 because we can have pending process exits recorded in
3265 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3266 an additional lp->status_p flag. */
3267 if (lp->status == 0 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3271 if (!target_can_async_p ())
3273 /* Causes SIGINT to be passed on to the attached process. */
3277 /* But if we don't find a pending event, we'll have to wait. */
3283 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3286 - If the thread group leader exits while other threads in the
3287 thread group still exist, waitpid(TGID, ...) hangs. That
3288 waitpid won't return an exit status until the other threads
3289 in the group are reapped.
3291 - When a non-leader thread execs, that thread just vanishes
3292 without reporting an exit (so we'd hang if we waited for it
3293 explicitly in that case). The exec event is reported to
3297 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3298 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3299 lwpid = my_waitpid (-1, &status, WNOHANG);
3301 if (debug_linux_nat)
3302 fprintf_unfiltered (gdb_stdlog,
3303 "LNW: waitpid(-1, ...) returned %d, %s\n",
3304 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3308 /* If this is true, then we paused LWPs momentarily, and may
3309 now have pending events to handle. */
3312 if (debug_linux_nat)
3314 fprintf_unfiltered (gdb_stdlog,
3315 "LLW: waitpid %ld received %s\n",
3316 (long) lwpid, status_to_str (status));
3319 lp = linux_nat_filter_event (lwpid, status, &new_pending);
3321 /* STATUS is now no longer valid, use LP->STATUS instead. */
3324 if (lp && !ptid_match (lp->ptid, ptid))
3326 gdb_assert (lp->resumed);
3328 if (debug_linux_nat)
3330 "LWP %ld got an event %06x, leaving pending.\n",
3331 ptid_get_lwp (lp->ptid), lp->status);
3333 if (WIFSTOPPED (lp->status))
3335 if (WSTOPSIG (lp->status) != SIGSTOP)
3337 /* Cancel breakpoint hits. The breakpoint may
3338 be removed before we fetch events from this
3339 process to report to the core. It is best
3340 not to assume the moribund breakpoints
3341 heuristic always handles these cases --- it
3342 could be too many events go through to the
3343 core before this one is handled. All-stop
3344 always cancels breakpoint hits in all
3347 && linux_nat_lp_status_is_event (lp)
3348 && cancel_breakpoint (lp))
3350 /* Throw away the SIGTRAP. */
3353 if (debug_linux_nat)
3355 "LLW: LWP %ld hit a breakpoint while"
3356 " waiting for another process;"
3358 ptid_get_lwp (lp->ptid));
3364 else if (WIFEXITED (lp->status) || WIFSIGNALED (lp->status))
3366 if (debug_linux_nat)
3368 "Process %ld exited while stopping LWPs\n",
3369 ptid_get_lwp (lp->ptid));
3371 /* This was the last lwp in the process. Since
3372 events are serialized to GDB core, and we can't
3373 report this one right now, but GDB core and the
3374 other target layers will want to be notified
3375 about the exit code/signal, leave the status
3376 pending for the next time we're able to report
3379 /* Dead LWP's aren't expected to reported a pending
3383 /* Store the pending event in the waitstatus as
3384 well, because W_EXITCODE(0,0) == 0. */
3385 store_waitstatus (&lp->waitstatus, lp->status);
3394 /* Some LWP now has a pending event. Go all the way
3395 back to check it. */
3401 /* We got an event to report to the core. */
3405 /* Retry until nothing comes out of waitpid. A single
3406 SIGCHLD can indicate more than one child stopped. */
3410 /* Check for zombie thread group leaders. Those can't be reaped
3411 until all other threads in the thread group are. */
3412 check_zombie_leaders ();
3414 /* If there are no resumed children left, bail. We'd be stuck
3415 forever in the sigsuspend call below otherwise. */
3416 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3418 if (debug_linux_nat)
3419 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3421 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3423 if (!target_can_async_p ())
3424 clear_sigint_trap ();
3426 restore_child_signals_mask (&prev_mask);
3427 return minus_one_ptid;
3430 /* No interesting event to report to the core. */
3432 if (target_options & TARGET_WNOHANG)
3434 if (debug_linux_nat)
3435 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3437 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3438 restore_child_signals_mask (&prev_mask);
3439 return minus_one_ptid;
3442 /* We shouldn't end up here unless we want to try again. */
3443 gdb_assert (lp == NULL);
3445 /* Block until we get an event reported with SIGCHLD. */
3446 if (debug_linux_nat)
3447 fprintf_unfiltered (gdb_stdlog, "LNW: about to sigsuspend\n");
3448 sigsuspend (&suspend_mask);
3451 if (!target_can_async_p ())
3452 clear_sigint_trap ();
3456 status = lp->status;
3459 /* Don't report signals that GDB isn't interested in, such as
3460 signals that are neither printed nor stopped upon. Stopping all
3461 threads can be a bit time-consuming so if we want decent
3462 performance with heavily multi-threaded programs, especially when
3463 they're using a high frequency timer, we'd better avoid it if we
3466 if (WIFSTOPPED (status))
3468 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3470 /* When using hardware single-step, we need to report every signal.
3471 Otherwise, signals in pass_mask may be short-circuited. */
3473 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status)))
3475 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3476 here? It is not clear we should. GDB may not expect
3477 other threads to run. On the other hand, not resuming
3478 newly attached threads may cause an unwanted delay in
3479 getting them running. */
3480 registers_changed ();
3481 if (linux_nat_prepare_to_resume != NULL)
3482 linux_nat_prepare_to_resume (lp);
3483 linux_ops->to_resume (linux_ops,
3484 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3486 if (debug_linux_nat)
3487 fprintf_unfiltered (gdb_stdlog,
3488 "LLW: %s %s, %s (preempt 'handle')\n",
3490 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3491 target_pid_to_str (lp->ptid),
3492 (signo != GDB_SIGNAL_0
3493 ? strsignal (gdb_signal_to_host (signo))
3501 /* Only do the below in all-stop, as we currently use SIGINT
3502 to implement target_stop (see linux_nat_stop) in
3504 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3506 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3507 forwarded to the entire process group, that is, all LWPs
3508 will receive it - unless they're using CLONE_THREAD to
3509 share signals. Since we only want to report it once, we
3510 mark it as ignored for all LWPs except this one. */
3511 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid)),
3512 set_ignore_sigint, NULL);
3513 lp->ignore_sigint = 0;
3516 maybe_clear_ignore_sigint (lp);
3520 /* This LWP is stopped now. */
3523 if (debug_linux_nat)
3524 fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
3525 status_to_str (status), target_pid_to_str (lp->ptid));
3529 /* Now stop all other LWP's ... */
3530 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3532 /* ... and wait until all of them have reported back that
3533 they're no longer running. */
3534 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3536 /* If we're not waiting for a specific LWP, choose an event LWP
3537 from among those that have had events. Giving equal priority
3538 to all LWPs that have had events helps prevent
3540 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3541 select_event_lwp (ptid, &lp, &status);
3543 /* Now that we've selected our final event LWP, cancel any
3544 breakpoints in other LWPs that have hit a GDB breakpoint.
3545 See the comment in cancel_breakpoints_callback to find out
3547 iterate_over_lwps (minus_one_ptid, cancel_breakpoints_callback, lp);
3549 /* We'll need this to determine whether to report a SIGSTOP as
3550 TARGET_WAITKIND_0. Need to take a copy because
3551 resume_clear_callback clears it. */
3552 last_resume_kind = lp->last_resume_kind;
3554 /* In all-stop, from the core's perspective, all LWPs are now
3555 stopped until a new resume action is sent over. */
3556 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3561 last_resume_kind = lp->last_resume_kind;
3562 resume_clear_callback (lp, NULL);
3565 if (linux_nat_status_is_event (status))
3567 if (debug_linux_nat)
3568 fprintf_unfiltered (gdb_stdlog,
3569 "LLW: trap ptid is %s.\n",
3570 target_pid_to_str (lp->ptid));
3573 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3575 *ourstatus = lp->waitstatus;
3576 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3579 store_waitstatus (ourstatus, status);
3581 if (debug_linux_nat)
3582 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3584 restore_child_signals_mask (&prev_mask);
3586 if (last_resume_kind == resume_stop
3587 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3588 && WSTOPSIG (status) == SIGSTOP)
3590 /* A thread that has been requested to stop by GDB with
3591 target_stop, and it stopped cleanly, so report as SIG0. The
3592 use of SIGSTOP is an implementation detail. */
3593 ourstatus->value.sig = GDB_SIGNAL_0;
3596 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3597 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3600 lp->core = linux_common_core_of_thread (lp->ptid);
3605 /* Resume LWPs that are currently stopped without any pending status
3606 to report, but are resumed from the core's perspective. */
3609 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3611 ptid_t *wait_ptid_p = data;
3616 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3618 struct regcache *regcache = get_thread_regcache (lp->ptid);
3619 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3620 CORE_ADDR pc = regcache_read_pc (regcache);
3622 gdb_assert (is_executing (lp->ptid));
3624 /* Don't bother if there's a breakpoint at PC that we'd hit
3625 immediately, and we're not waiting for this LWP. */
3626 if (!ptid_match (lp->ptid, *wait_ptid_p))
3628 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3632 if (debug_linux_nat)
3633 fprintf_unfiltered (gdb_stdlog,
3634 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3635 target_pid_to_str (lp->ptid),
3636 paddress (gdbarch, pc),
3639 registers_changed ();
3640 if (linux_nat_prepare_to_resume != NULL)
3641 linux_nat_prepare_to_resume (lp);
3642 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3643 lp->step, GDB_SIGNAL_0);
3645 lp->stopped_by_watchpoint = 0;
3652 linux_nat_wait (struct target_ops *ops,
3653 ptid_t ptid, struct target_waitstatus *ourstatus,
3658 if (debug_linux_nat)
3660 char *options_string;
3662 options_string = target_options_to_string (target_options);
3663 fprintf_unfiltered (gdb_stdlog,
3664 "linux_nat_wait: [%s], [%s]\n",
3665 target_pid_to_str (ptid),
3667 xfree (options_string);
3670 /* Flush the async file first. */
3671 if (target_can_async_p ())
3672 async_file_flush ();
3674 /* Resume LWPs that are currently stopped without any pending status
3675 to report, but are resumed from the core's perspective. LWPs get
3676 in this state if we find them stopping at a time we're not
3677 interested in reporting the event (target_wait on a
3678 specific_process, for example, see linux_nat_wait_1), and
3679 meanwhile the event became uninteresting. Don't bother resuming
3680 LWPs we're not going to wait for if they'd stop immediately. */
3682 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3684 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3686 /* If we requested any event, and something came out, assume there
3687 may be more. If we requested a specific lwp or process, also
3688 assume there may be more. */
3689 if (target_can_async_p ()
3690 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3691 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3692 || !ptid_equal (ptid, minus_one_ptid)))
3695 /* Get ready for the next event. */
3696 if (target_can_async_p ())
3697 target_async (inferior_event_handler, 0);
3703 kill_callback (struct lwp_info *lp, void *data)
3705 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3708 kill_lwp (ptid_get_lwp (lp->ptid), SIGKILL);
3709 if (debug_linux_nat)
3711 int save_errno = errno;
3713 fprintf_unfiltered (gdb_stdlog,
3714 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3715 target_pid_to_str (lp->ptid),
3716 save_errno ? safe_strerror (save_errno) : "OK");
3719 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3722 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3723 if (debug_linux_nat)
3725 int save_errno = errno;
3727 fprintf_unfiltered (gdb_stdlog,
3728 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3729 target_pid_to_str (lp->ptid),
3730 save_errno ? safe_strerror (save_errno) : "OK");
3737 kill_wait_callback (struct lwp_info *lp, void *data)
3741 /* We must make sure that there are no pending events (delayed
3742 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3743 program doesn't interfere with any following debugging session. */
3745 /* For cloned processes we must check both with __WCLONE and
3746 without, since the exit status of a cloned process isn't reported
3752 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3753 if (pid != (pid_t) -1)
3755 if (debug_linux_nat)
3756 fprintf_unfiltered (gdb_stdlog,
3757 "KWC: wait %s received unknown.\n",
3758 target_pid_to_str (lp->ptid));
3759 /* The Linux kernel sometimes fails to kill a thread
3760 completely after PTRACE_KILL; that goes from the stop
3761 point in do_fork out to the one in
3762 get_signal_to_deliever and waits again. So kill it
3764 kill_callback (lp, NULL);
3767 while (pid == ptid_get_lwp (lp->ptid));
3769 gdb_assert (pid == -1 && errno == ECHILD);
3774 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3775 if (pid != (pid_t) -1)
3777 if (debug_linux_nat)
3778 fprintf_unfiltered (gdb_stdlog,
3779 "KWC: wait %s received unk.\n",
3780 target_pid_to_str (lp->ptid));
3781 /* See the call to kill_callback above. */
3782 kill_callback (lp, NULL);
3785 while (pid == ptid_get_lwp (lp->ptid));
3787 gdb_assert (pid == -1 && errno == ECHILD);
3792 linux_nat_kill (struct target_ops *ops)
3794 struct target_waitstatus last;
3798 /* If we're stopped while forking and we haven't followed yet,
3799 kill the other task. We need to do this first because the
3800 parent will be sleeping if this is a vfork. */
3802 get_last_target_status (&last_ptid, &last);
3804 if (last.kind == TARGET_WAITKIND_FORKED
3805 || last.kind == TARGET_WAITKIND_VFORKED)
3807 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3810 /* Let the arch-specific native code know this process is
3812 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3815 if (forks_exist_p ())
3816 linux_fork_killall ();
3819 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3821 /* Stop all threads before killing them, since ptrace requires
3822 that the thread is stopped to sucessfully PTRACE_KILL. */
3823 iterate_over_lwps (ptid, stop_callback, NULL);
3824 /* ... and wait until all of them have reported back that
3825 they're no longer running. */
3826 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3828 /* Kill all LWP's ... */
3829 iterate_over_lwps (ptid, kill_callback, NULL);
3831 /* ... and wait until we've flushed all events. */
3832 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3835 target_mourn_inferior ();
3839 linux_nat_mourn_inferior (struct target_ops *ops)
3841 int pid = ptid_get_pid (inferior_ptid);
3843 purge_lwp_list (pid);
3845 if (! forks_exist_p ())
3846 /* Normal case, no other forks available. */
3847 linux_ops->to_mourn_inferior (ops);
3849 /* Multi-fork case. The current inferior_ptid has exited, but
3850 there are other viable forks to debug. Delete the exiting
3851 one and context-switch to the first available. */
3852 linux_fork_mourn_inferior ();
3854 /* Let the arch-specific native code know this process is gone. */
3855 linux_nat_forget_process (pid);
3858 /* Convert a native/host siginfo object, into/from the siginfo in the
3859 layout of the inferiors' architecture. */
3862 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3866 if (linux_nat_siginfo_fixup != NULL)
3867 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3869 /* If there was no callback, or the callback didn't do anything,
3870 then just do a straight memcpy. */
3874 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3876 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3880 static enum target_xfer_status
3881 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3882 const char *annex, gdb_byte *readbuf,
3883 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3884 ULONGEST *xfered_len)
3888 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3890 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3891 gdb_assert (readbuf || writebuf);
3893 pid = ptid_get_lwp (inferior_ptid);
3895 pid = ptid_get_pid (inferior_ptid);
3897 if (offset > sizeof (siginfo))
3898 return TARGET_XFER_E_IO;
3901 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3903 return TARGET_XFER_E_IO;
3905 /* When GDB is built as a 64-bit application, ptrace writes into
3906 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3907 inferior with a 64-bit GDB should look the same as debugging it
3908 with a 32-bit GDB, we need to convert it. GDB core always sees
3909 the converted layout, so any read/write will have to be done
3911 siginfo_fixup (&siginfo, inf_siginfo, 0);
3913 if (offset + len > sizeof (siginfo))
3914 len = sizeof (siginfo) - offset;
3916 if (readbuf != NULL)
3917 memcpy (readbuf, inf_siginfo + offset, len);
3920 memcpy (inf_siginfo + offset, writebuf, len);
3922 /* Convert back to ptrace layout before flushing it out. */
3923 siginfo_fixup (&siginfo, inf_siginfo, 1);
3926 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3928 return TARGET_XFER_E_IO;
3932 return TARGET_XFER_OK;
3935 static enum target_xfer_status
3936 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3937 const char *annex, gdb_byte *readbuf,
3938 const gdb_byte *writebuf,
3939 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3941 struct cleanup *old_chain;
3942 enum target_xfer_status xfer;
3944 if (object == TARGET_OBJECT_SIGNAL_INFO)
3945 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3946 offset, len, xfered_len);
3948 /* The target is connected but no live inferior is selected. Pass
3949 this request down to a lower stratum (e.g., the executable
3951 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3952 return TARGET_XFER_EOF;
3954 old_chain = save_inferior_ptid ();
3956 if (ptid_lwp_p (inferior_ptid))
3957 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3959 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3960 offset, len, xfered_len);
3962 do_cleanups (old_chain);
3967 linux_thread_alive (ptid_t ptid)
3971 gdb_assert (ptid_lwp_p (ptid));
3973 /* Send signal 0 instead of anything ptrace, because ptracing a
3974 running thread errors out claiming that the thread doesn't
3976 err = kill_lwp (ptid_get_lwp (ptid), 0);
3978 if (debug_linux_nat)
3979 fprintf_unfiltered (gdb_stdlog,
3980 "LLTA: KILL(SIG0) %s (%s)\n",
3981 target_pid_to_str (ptid),
3982 err ? safe_strerror (tmp_errno) : "OK");
3991 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
3993 return linux_thread_alive (ptid);
3997 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
3999 static char buf[64];
4001 if (ptid_lwp_p (ptid)
4002 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
4003 || num_lwps (ptid_get_pid (ptid)) > 1))
4005 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
4009 return normal_pid_to_str (ptid);
4013 linux_nat_thread_name (struct target_ops *self, struct thread_info *thr)
4015 int pid = ptid_get_pid (thr->ptid);
4016 long lwp = ptid_get_lwp (thr->ptid);
4017 #define FORMAT "/proc/%d/task/%ld/comm"
4018 char buf[sizeof (FORMAT) + 30];
4020 char *result = NULL;
4022 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
4023 comm_file = gdb_fopen_cloexec (buf, "r");
4026 /* Not exported by the kernel, so we define it here. */
4028 static char line[COMM_LEN + 1];
4030 if (fgets (line, sizeof (line), comm_file))
4032 char *nl = strchr (line, '\n');
4049 /* Accepts an integer PID; Returns a string representing a file that
4050 can be opened to get the symbols for the child process. */
4053 linux_child_pid_to_exec_file (struct target_ops *self, int pid)
4055 static char buf[PATH_MAX];
4056 char name[PATH_MAX];
4058 xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
4059 memset (buf, 0, PATH_MAX);
4060 if (readlink (name, buf, PATH_MAX - 1) <= 0)
4066 /* Records the thread's register state for the corefile note
4070 linux_nat_collect_thread_registers (const struct regcache *regcache,
4071 ptid_t ptid, bfd *obfd,
4072 char *note_data, int *note_size,
4073 enum gdb_signal stop_signal)
4075 struct gdbarch *gdbarch = get_regcache_arch (regcache);
4076 const struct regset *regset;
4078 gdb_gregset_t gregs;
4079 gdb_fpregset_t fpregs;
4081 core_regset_p = gdbarch_regset_from_core_section_p (gdbarch);
4084 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg",
4086 != NULL && regset->collect_regset != NULL)
4087 regset->collect_regset (regset, regcache, -1, &gregs, sizeof (gregs));
4089 fill_gregset (regcache, &gregs, -1);
4091 note_data = (char *) elfcore_write_prstatus
4092 (obfd, note_data, note_size, ptid_get_lwp (ptid),
4093 gdb_signal_to_host (stop_signal), &gregs);
4096 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
4098 != NULL && regset->collect_regset != NULL)
4099 regset->collect_regset (regset, regcache, -1, &fpregs, sizeof (fpregs));
4101 fill_fpregset (regcache, &fpregs, -1);
4103 note_data = (char *) elfcore_write_prfpreg (obfd, note_data, note_size,
4104 &fpregs, sizeof (fpregs));
4109 /* Fills the "to_make_corefile_note" target vector. Builds the note
4110 section for a corefile, and returns it in a malloc buffer. */
4113 linux_nat_make_corefile_notes (struct target_ops *self,
4114 bfd *obfd, int *note_size)
4116 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4117 converted to gdbarch_core_regset_sections, this function can go away. */
4118 return linux_make_corefile_notes (target_gdbarch (), obfd, note_size,
4119 linux_nat_collect_thread_registers);
4122 /* Implement the to_xfer_partial interface for memory reads using the /proc
4123 filesystem. Because we can use a single read() call for /proc, this
4124 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4125 but it doesn't support writes. */
4127 static enum target_xfer_status
4128 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
4129 const char *annex, gdb_byte *readbuf,
4130 const gdb_byte *writebuf,
4131 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
4137 if (object != TARGET_OBJECT_MEMORY || !readbuf)
4140 /* Don't bother for one word. */
4141 if (len < 3 * sizeof (long))
4142 return TARGET_XFER_EOF;
4144 /* We could keep this file open and cache it - possibly one per
4145 thread. That requires some juggling, but is even faster. */
4146 xsnprintf (filename, sizeof filename, "/proc/%d/mem",
4147 ptid_get_pid (inferior_ptid));
4148 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
4150 return TARGET_XFER_EOF;
4152 /* If pread64 is available, use it. It's faster if the kernel
4153 supports it (only one syscall), and it's 64-bit safe even on
4154 32-bit platforms (for instance, SPARC debugging a SPARC64
4157 if (pread64 (fd, readbuf, len, offset) != len)
4159 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
4168 return TARGET_XFER_EOF;
4172 return TARGET_XFER_OK;
4177 /* Enumerate spufs IDs for process PID. */
4179 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
4181 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4183 LONGEST written = 0;
4186 struct dirent *entry;
4188 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4189 dir = opendir (path);
4194 while ((entry = readdir (dir)) != NULL)
4200 fd = atoi (entry->d_name);
4204 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4205 if (stat (path, &st) != 0)
4207 if (!S_ISDIR (st.st_mode))
4210 if (statfs (path, &stfs) != 0)
4212 if (stfs.f_type != SPUFS_MAGIC)
4215 if (pos >= offset && pos + 4 <= offset + len)
4217 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4227 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4228 object type, using the /proc file system. */
4230 static enum target_xfer_status
4231 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
4232 const char *annex, gdb_byte *readbuf,
4233 const gdb_byte *writebuf,
4234 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
4239 int pid = ptid_get_pid (inferior_ptid);
4244 return TARGET_XFER_E_IO;
4247 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
4250 return TARGET_XFER_E_IO;
4252 return TARGET_XFER_EOF;
4255 *xfered_len = (ULONGEST) l;
4256 return TARGET_XFER_OK;
4261 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4262 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4264 return TARGET_XFER_E_IO;
4267 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4270 return TARGET_XFER_EOF;
4274 ret = write (fd, writebuf, (size_t) len);
4276 ret = read (fd, readbuf, (size_t) len);
4281 return TARGET_XFER_E_IO;
4283 return TARGET_XFER_EOF;
4286 *xfered_len = (ULONGEST) ret;
4287 return TARGET_XFER_OK;
4292 /* Parse LINE as a signal set and add its set bits to SIGS. */
4295 add_line_to_sigset (const char *line, sigset_t *sigs)
4297 int len = strlen (line) - 1;
4301 if (line[len] != '\n')
4302 error (_("Could not parse signal set: %s"), line);
4310 if (*p >= '0' && *p <= '9')
4312 else if (*p >= 'a' && *p <= 'f')
4313 digit = *p - 'a' + 10;
4315 error (_("Could not parse signal set: %s"), line);
4320 sigaddset (sigs, signum + 1);
4322 sigaddset (sigs, signum + 2);
4324 sigaddset (sigs, signum + 3);
4326 sigaddset (sigs, signum + 4);
4332 /* Find process PID's pending signals from /proc/pid/status and set
4336 linux_proc_pending_signals (int pid, sigset_t *pending,
4337 sigset_t *blocked, sigset_t *ignored)
4340 char buffer[PATH_MAX], fname[PATH_MAX];
4341 struct cleanup *cleanup;
4343 sigemptyset (pending);
4344 sigemptyset (blocked);
4345 sigemptyset (ignored);
4346 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4347 procfile = gdb_fopen_cloexec (fname, "r");
4348 if (procfile == NULL)
4349 error (_("Could not open %s"), fname);
4350 cleanup = make_cleanup_fclose (procfile);
4352 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4354 /* Normal queued signals are on the SigPnd line in the status
4355 file. However, 2.6 kernels also have a "shared" pending
4356 queue for delivering signals to a thread group, so check for
4359 Unfortunately some Red Hat kernels include the shared pending
4360 queue but not the ShdPnd status field. */
4362 if (strncmp (buffer, "SigPnd:\t", 8) == 0)
4363 add_line_to_sigset (buffer + 8, pending);
4364 else if (strncmp (buffer, "ShdPnd:\t", 8) == 0)
4365 add_line_to_sigset (buffer + 8, pending);
4366 else if (strncmp (buffer, "SigBlk:\t", 8) == 0)
4367 add_line_to_sigset (buffer + 8, blocked);
4368 else if (strncmp (buffer, "SigIgn:\t", 8) == 0)
4369 add_line_to_sigset (buffer + 8, ignored);
4372 do_cleanups (cleanup);
4375 static enum target_xfer_status
4376 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4377 const char *annex, gdb_byte *readbuf,
4378 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4379 ULONGEST *xfered_len)
4381 gdb_assert (object == TARGET_OBJECT_OSDATA);
4383 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4384 if (*xfered_len == 0)
4385 return TARGET_XFER_EOF;
4387 return TARGET_XFER_OK;
4390 static enum target_xfer_status
4391 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4392 const char *annex, gdb_byte *readbuf,
4393 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4394 ULONGEST *xfered_len)
4396 enum target_xfer_status xfer;
4398 if (object == TARGET_OBJECT_AUXV)
4399 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4400 offset, len, xfered_len);
4402 if (object == TARGET_OBJECT_OSDATA)
4403 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4404 offset, len, xfered_len);
4406 if (object == TARGET_OBJECT_SPU)
4407 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4408 offset, len, xfered_len);
4410 /* GDB calculates all the addresses in possibly larget width of the address.
4411 Address width needs to be masked before its final use - either by
4412 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4414 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4416 if (object == TARGET_OBJECT_MEMORY)
4418 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4420 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4421 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4424 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4425 offset, len, xfered_len);
4426 if (xfer != TARGET_XFER_EOF)
4429 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4430 offset, len, xfered_len);
4434 cleanup_target_stop (void *arg)
4436 ptid_t *ptid = (ptid_t *) arg;
4438 gdb_assert (arg != NULL);
4441 target_resume (*ptid, 0, GDB_SIGNAL_0);
4444 static VEC(static_tracepoint_marker_p) *
4445 linux_child_static_tracepoint_markers_by_strid (struct target_ops *self,
4448 char s[IPA_CMD_BUF_SIZE];
4449 struct cleanup *old_chain;
4450 int pid = ptid_get_pid (inferior_ptid);
4451 VEC(static_tracepoint_marker_p) *markers = NULL;
4452 struct static_tracepoint_marker *marker = NULL;
4454 ptid_t ptid = ptid_build (pid, 0, 0);
4459 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4460 s[sizeof ("qTfSTM")] = 0;
4462 agent_run_command (pid, s, strlen (s) + 1);
4464 old_chain = make_cleanup (free_current_marker, &marker);
4465 make_cleanup (cleanup_target_stop, &ptid);
4470 marker = XCNEW (struct static_tracepoint_marker);
4474 parse_static_tracepoint_marker_definition (p, &p, marker);
4476 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4478 VEC_safe_push (static_tracepoint_marker_p,
4484 release_static_tracepoint_marker (marker);
4485 memset (marker, 0, sizeof (*marker));
4488 while (*p++ == ','); /* comma-separated list */
4490 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4491 s[sizeof ("qTsSTM")] = 0;
4492 agent_run_command (pid, s, strlen (s) + 1);
4496 do_cleanups (old_chain);
4501 /* Create a prototype generic GNU/Linux target. The client can override
4502 it with local methods. */
4505 linux_target_install_ops (struct target_ops *t)
4507 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4508 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4509 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4510 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4511 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4512 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4513 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4514 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4515 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4516 t->to_post_attach = linux_child_post_attach;
4517 t->to_follow_fork = linux_child_follow_fork;
4518 t->to_make_corefile_notes = linux_nat_make_corefile_notes;
4520 super_xfer_partial = t->to_xfer_partial;
4521 t->to_xfer_partial = linux_xfer_partial;
4523 t->to_static_tracepoint_markers_by_strid
4524 = linux_child_static_tracepoint_markers_by_strid;
4530 struct target_ops *t;
4532 t = inf_ptrace_target ();
4533 linux_target_install_ops (t);
4539 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4541 struct target_ops *t;
4543 t = inf_ptrace_trad_target (register_u_offset);
4544 linux_target_install_ops (t);
4549 /* target_is_async_p implementation. */
4552 linux_nat_is_async_p (struct target_ops *ops)
4554 /* NOTE: palves 2008-03-21: We're only async when the user requests
4555 it explicitly with the "set target-async" command.
4556 Someday, linux will always be async. */
4557 return target_async_permitted;
4560 /* target_can_async_p implementation. */
4563 linux_nat_can_async_p (struct target_ops *ops)
4565 /* NOTE: palves 2008-03-21: We're only async when the user requests
4566 it explicitly with the "set target-async" command.
4567 Someday, linux will always be async. */
4568 return target_async_permitted;
4572 linux_nat_supports_non_stop (struct target_ops *self)
4577 /* True if we want to support multi-process. To be removed when GDB
4578 supports multi-exec. */
4580 int linux_multi_process = 1;
4583 linux_nat_supports_multi_process (struct target_ops *self)
4585 return linux_multi_process;
4589 linux_nat_supports_disable_randomization (struct target_ops *self)
4591 #ifdef HAVE_PERSONALITY
4598 static int async_terminal_is_ours = 1;
4600 /* target_terminal_inferior implementation.
4602 This is a wrapper around child_terminal_inferior to add async support. */
4605 linux_nat_terminal_inferior (struct target_ops *self)
4607 if (!target_is_async_p ())
4609 /* Async mode is disabled. */
4610 child_terminal_inferior (self);
4614 child_terminal_inferior (self);
4616 /* Calls to target_terminal_*() are meant to be idempotent. */
4617 if (!async_terminal_is_ours)
4620 delete_file_handler (input_fd);
4621 async_terminal_is_ours = 0;
4625 /* target_terminal_ours implementation.
4627 This is a wrapper around child_terminal_ours to add async support (and
4628 implement the target_terminal_ours vs target_terminal_ours_for_output
4629 distinction). child_terminal_ours is currently no different than
4630 child_terminal_ours_for_output.
4631 We leave target_terminal_ours_for_output alone, leaving it to
4632 child_terminal_ours_for_output. */
4635 linux_nat_terminal_ours (struct target_ops *self)
4637 if (!target_is_async_p ())
4639 /* Async mode is disabled. */
4640 child_terminal_ours (self);
4644 /* GDB should never give the terminal to the inferior if the
4645 inferior is running in the background (run&, continue&, etc.),
4646 but claiming it sure should. */
4647 child_terminal_ours (self);
4649 if (async_terminal_is_ours)
4652 clear_sigint_trap ();
4653 add_file_handler (input_fd, stdin_event_handler, 0);
4654 async_terminal_is_ours = 1;
4657 static void (*async_client_callback) (enum inferior_event_type event_type,
4659 static void *async_client_context;
4661 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4662 so we notice when any child changes state, and notify the
4663 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4664 above to wait for the arrival of a SIGCHLD. */
4667 sigchld_handler (int signo)
4669 int old_errno = errno;
4671 if (debug_linux_nat)
4672 ui_file_write_async_safe (gdb_stdlog,
4673 "sigchld\n", sizeof ("sigchld\n") - 1);
4675 if (signo == SIGCHLD
4676 && linux_nat_event_pipe[0] != -1)
4677 async_file_mark (); /* Let the event loop know that there are
4678 events to handle. */
4683 /* Callback registered with the target events file descriptor. */
4686 handle_target_event (int error, gdb_client_data client_data)
4688 (*async_client_callback) (INF_REG_EVENT, async_client_context);
4691 /* Create/destroy the target events pipe. Returns previous state. */
4694 linux_async_pipe (int enable)
4696 int previous = (linux_nat_event_pipe[0] != -1);
4698 if (previous != enable)
4702 /* Block child signals while we create/destroy the pipe, as
4703 their handler writes to it. */
4704 block_child_signals (&prev_mask);
4708 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4709 internal_error (__FILE__, __LINE__,
4710 "creating event pipe failed.");
4712 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4713 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4717 close (linux_nat_event_pipe[0]);
4718 close (linux_nat_event_pipe[1]);
4719 linux_nat_event_pipe[0] = -1;
4720 linux_nat_event_pipe[1] = -1;
4723 restore_child_signals_mask (&prev_mask);
4729 /* target_async implementation. */
4732 linux_nat_async (struct target_ops *ops,
4733 void (*callback) (enum inferior_event_type event_type,
4737 if (callback != NULL)
4739 async_client_callback = callback;
4740 async_client_context = context;
4741 if (!linux_async_pipe (1))
4743 add_file_handler (linux_nat_event_pipe[0],
4744 handle_target_event, NULL);
4745 /* There may be pending events to handle. Tell the event loop
4752 async_client_callback = callback;
4753 async_client_context = context;
4754 delete_file_handler (linux_nat_event_pipe[0]);
4755 linux_async_pipe (0);
4760 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4764 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4768 if (debug_linux_nat)
4769 fprintf_unfiltered (gdb_stdlog,
4770 "LNSL: running -> suspending %s\n",
4771 target_pid_to_str (lwp->ptid));
4774 if (lwp->last_resume_kind == resume_stop)
4776 if (debug_linux_nat)
4777 fprintf_unfiltered (gdb_stdlog,
4778 "linux-nat: already stopping LWP %ld at "
4780 ptid_get_lwp (lwp->ptid));
4784 stop_callback (lwp, NULL);
4785 lwp->last_resume_kind = resume_stop;
4789 /* Already known to be stopped; do nothing. */
4791 if (debug_linux_nat)
4793 if (find_thread_ptid (lwp->ptid)->stop_requested)
4794 fprintf_unfiltered (gdb_stdlog,
4795 "LNSL: already stopped/stop_requested %s\n",
4796 target_pid_to_str (lwp->ptid));
4798 fprintf_unfiltered (gdb_stdlog,
4799 "LNSL: already stopped/no "
4800 "stop_requested yet %s\n",
4801 target_pid_to_str (lwp->ptid));
4808 linux_nat_stop (struct target_ops *self, ptid_t ptid)
4811 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4813 linux_ops->to_stop (linux_ops, ptid);
4817 linux_nat_close (struct target_ops *self)
4819 /* Unregister from the event loop. */
4820 if (linux_nat_is_async_p (self))
4821 linux_nat_async (self, NULL, NULL);
4823 if (linux_ops->to_close)
4824 linux_ops->to_close (linux_ops);
4829 /* When requests are passed down from the linux-nat layer to the
4830 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4831 used. The address space pointer is stored in the inferior object,
4832 but the common code that is passed such ptid can't tell whether
4833 lwpid is a "main" process id or not (it assumes so). We reverse
4834 look up the "main" process id from the lwp here. */
4836 static struct address_space *
4837 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4839 struct lwp_info *lwp;
4840 struct inferior *inf;
4843 if (ptid_get_lwp (ptid) == 0)
4845 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4847 lwp = find_lwp_pid (ptid);
4848 pid = ptid_get_pid (lwp->ptid);
4852 /* A (pid,lwpid,0) ptid. */
4853 pid = ptid_get_pid (ptid);
4856 inf = find_inferior_pid (pid);
4857 gdb_assert (inf != NULL);
4861 /* Return the cached value of the processor core for thread PTID. */
4864 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4866 struct lwp_info *info = find_lwp_pid (ptid);
4874 linux_nat_add_target (struct target_ops *t)
4876 /* Save the provided single-threaded target. We save this in a separate
4877 variable because another target we've inherited from (e.g. inf-ptrace)
4878 may have saved a pointer to T; we want to use it for the final
4879 process stratum target. */
4880 linux_ops_saved = *t;
4881 linux_ops = &linux_ops_saved;
4883 /* Override some methods for multithreading. */
4884 t->to_create_inferior = linux_nat_create_inferior;
4885 t->to_attach = linux_nat_attach;
4886 t->to_detach = linux_nat_detach;
4887 t->to_resume = linux_nat_resume;
4888 t->to_wait = linux_nat_wait;
4889 t->to_pass_signals = linux_nat_pass_signals;
4890 t->to_xfer_partial = linux_nat_xfer_partial;
4891 t->to_kill = linux_nat_kill;
4892 t->to_mourn_inferior = linux_nat_mourn_inferior;
4893 t->to_thread_alive = linux_nat_thread_alive;
4894 t->to_pid_to_str = linux_nat_pid_to_str;
4895 t->to_thread_name = linux_nat_thread_name;
4896 t->to_has_thread_control = tc_schedlock;
4897 t->to_thread_address_space = linux_nat_thread_address_space;
4898 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4899 t->to_stopped_data_address = linux_nat_stopped_data_address;
4901 t->to_can_async_p = linux_nat_can_async_p;
4902 t->to_is_async_p = linux_nat_is_async_p;
4903 t->to_supports_non_stop = linux_nat_supports_non_stop;
4904 t->to_async = linux_nat_async;
4905 t->to_terminal_inferior = linux_nat_terminal_inferior;
4906 t->to_terminal_ours = linux_nat_terminal_ours;
4908 super_close = t->to_close;
4909 t->to_close = linux_nat_close;
4911 /* Methods for non-stop support. */
4912 t->to_stop = linux_nat_stop;
4914 t->to_supports_multi_process = linux_nat_supports_multi_process;
4916 t->to_supports_disable_randomization
4917 = linux_nat_supports_disable_randomization;
4919 t->to_core_of_thread = linux_nat_core_of_thread;
4921 /* We don't change the stratum; this target will sit at
4922 process_stratum and thread_db will set at thread_stratum. This
4923 is a little strange, since this is a multi-threaded-capable
4924 target, but we want to be on the stack below thread_db, and we
4925 also want to be used for single-threaded processes. */
4930 /* Register a method to call whenever a new thread is attached. */
4932 linux_nat_set_new_thread (struct target_ops *t,
4933 void (*new_thread) (struct lwp_info *))
4935 /* Save the pointer. We only support a single registered instance
4936 of the GNU/Linux native target, so we do not need to map this to
4938 linux_nat_new_thread = new_thread;
4941 /* See declaration in linux-nat.h. */
4944 linux_nat_set_new_fork (struct target_ops *t,
4945 linux_nat_new_fork_ftype *new_fork)
4947 /* Save the pointer. */
4948 linux_nat_new_fork = new_fork;
4951 /* See declaration in linux-nat.h. */
4954 linux_nat_set_forget_process (struct target_ops *t,
4955 linux_nat_forget_process_ftype *fn)
4957 /* Save the pointer. */
4958 linux_nat_forget_process_hook = fn;
4961 /* See declaration in linux-nat.h. */
4964 linux_nat_forget_process (pid_t pid)
4966 if (linux_nat_forget_process_hook != NULL)
4967 linux_nat_forget_process_hook (pid);
4970 /* Register a method that converts a siginfo object between the layout
4971 that ptrace returns, and the layout in the architecture of the
4974 linux_nat_set_siginfo_fixup (struct target_ops *t,
4975 int (*siginfo_fixup) (siginfo_t *,
4979 /* Save the pointer. */
4980 linux_nat_siginfo_fixup = siginfo_fixup;
4983 /* Register a method to call prior to resuming a thread. */
4986 linux_nat_set_prepare_to_resume (struct target_ops *t,
4987 void (*prepare_to_resume) (struct lwp_info *))
4989 /* Save the pointer. */
4990 linux_nat_prepare_to_resume = prepare_to_resume;
4993 /* See linux-nat.h. */
4996 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
5000 pid = ptid_get_lwp (ptid);
5002 pid = ptid_get_pid (ptid);
5005 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
5008 memset (siginfo, 0, sizeof (*siginfo));
5014 /* Provide a prototype to silence -Wmissing-prototypes. */
5015 extern initialize_file_ftype _initialize_linux_nat;
5018 _initialize_linux_nat (void)
5020 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
5021 &debug_linux_nat, _("\
5022 Set debugging of GNU/Linux lwp module."), _("\
5023 Show debugging of GNU/Linux lwp module."), _("\
5024 Enables printf debugging output."),
5026 show_debug_linux_nat,
5027 &setdebuglist, &showdebuglist);
5029 /* Save this mask as the default. */
5030 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
5032 /* Install a SIGCHLD handler. */
5033 sigchld_action.sa_handler = sigchld_handler;
5034 sigemptyset (&sigchld_action.sa_mask);
5035 sigchld_action.sa_flags = SA_RESTART;
5037 /* Make it the default. */
5038 sigaction (SIGCHLD, &sigchld_action, NULL);
5040 /* Make sure we don't block SIGCHLD during a sigsuspend. */
5041 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
5042 sigdelset (&suspend_mask, SIGCHLD);
5044 sigemptyset (&blocked_mask);
5046 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
5047 support read-only process state. */
5048 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
5049 | PTRACE_O_TRACEVFORKDONE
5050 | PTRACE_O_TRACEVFORK
5051 | PTRACE_O_TRACEFORK
5052 | PTRACE_O_TRACEEXEC);
5056 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
5057 the GNU/Linux Threads library and therefore doesn't really belong
5060 /* Read variable NAME in the target and return its value if found.
5061 Otherwise return zero. It is assumed that the type of the variable
5065 get_signo (const char *name)
5067 struct bound_minimal_symbol ms;
5070 ms = lookup_minimal_symbol (name, NULL, NULL);
5071 if (ms.minsym == NULL)
5074 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
5075 sizeof (signo)) != 0)
5081 /* Return the set of signals used by the threads library in *SET. */
5084 lin_thread_get_thread_signals (sigset_t *set)
5086 struct sigaction action;
5087 int restart, cancel;
5089 sigemptyset (&blocked_mask);
5092 restart = get_signo ("__pthread_sig_restart");
5093 cancel = get_signo ("__pthread_sig_cancel");
5095 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5096 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5097 not provide any way for the debugger to query the signal numbers -
5098 fortunately they don't change! */
5101 restart = __SIGRTMIN;
5104 cancel = __SIGRTMIN + 1;
5106 sigaddset (set, restart);
5107 sigaddset (set, cancel);
5109 /* The GNU/Linux Threads library makes terminating threads send a
5110 special "cancel" signal instead of SIGCHLD. Make sure we catch
5111 those (to prevent them from terminating GDB itself, which is
5112 likely to be their default action) and treat them the same way as
5115 action.sa_handler = sigchld_handler;
5116 sigemptyset (&action.sa_mask);
5117 action.sa_flags = SA_RESTART;
5118 sigaction (cancel, &action, NULL);
5120 /* We block the "cancel" signal throughout this code ... */
5121 sigaddset (&blocked_mask, cancel);
5122 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
5124 /* ... except during a sigsuspend. */
5125 sigdelset (&suspend_mask, cancel);