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 = linux_ptrace_get_extended_event (status);
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
2366 && linux_is_extended_waitstatus (status))
2368 if (debug_linux_nat)
2369 fprintf_unfiltered (gdb_stdlog,
2370 "WL: Handling extended status 0x%06x\n",
2372 if (linux_handle_extended_wait (lp, status, 1))
2373 return wait_lwp (lp);
2379 /* Send a SIGSTOP to LP. */
2382 stop_callback (struct lwp_info *lp, void *data)
2384 if (!lp->stopped && !lp->signalled)
2388 if (debug_linux_nat)
2390 fprintf_unfiltered (gdb_stdlog,
2391 "SC: kill %s **<SIGSTOP>**\n",
2392 target_pid_to_str (lp->ptid));
2395 ret = kill_lwp (ptid_get_lwp (lp->ptid), SIGSTOP);
2396 if (debug_linux_nat)
2398 fprintf_unfiltered (gdb_stdlog,
2399 "SC: lwp kill %d %s\n",
2401 errno ? safe_strerror (errno) : "ERRNO-OK");
2405 gdb_assert (lp->status == 0);
2411 /* Request a stop on LWP. */
2414 linux_stop_lwp (struct lwp_info *lwp)
2416 stop_callback (lwp, NULL);
2419 /* Return non-zero if LWP PID has a pending SIGINT. */
2422 linux_nat_has_pending_sigint (int pid)
2424 sigset_t pending, blocked, ignored;
2426 linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
2428 if (sigismember (&pending, SIGINT)
2429 && !sigismember (&ignored, SIGINT))
2435 /* Set a flag in LP indicating that we should ignore its next SIGINT. */
2438 set_ignore_sigint (struct lwp_info *lp, void *data)
2440 /* If a thread has a pending SIGINT, consume it; otherwise, set a
2441 flag to consume the next one. */
2442 if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
2443 && WSTOPSIG (lp->status) == SIGINT)
2446 lp->ignore_sigint = 1;
2451 /* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
2452 This function is called after we know the LWP has stopped; if the LWP
2453 stopped before the expected SIGINT was delivered, then it will never have
2454 arrived. Also, if the signal was delivered to a shared queue and consumed
2455 by a different thread, it will never be delivered to this LWP. */
2458 maybe_clear_ignore_sigint (struct lwp_info *lp)
2460 if (!lp->ignore_sigint)
2463 if (!linux_nat_has_pending_sigint (ptid_get_lwp (lp->ptid)))
2465 if (debug_linux_nat)
2466 fprintf_unfiltered (gdb_stdlog,
2467 "MCIS: Clearing bogus flag for %s\n",
2468 target_pid_to_str (lp->ptid));
2469 lp->ignore_sigint = 0;
2473 /* Fetch the possible triggered data watchpoint info and store it in
2476 On some archs, like x86, that use debug registers to set
2477 watchpoints, it's possible that the way to know which watched
2478 address trapped, is to check the register that is used to select
2479 which address to watch. Problem is, between setting the watchpoint
2480 and reading back which data address trapped, the user may change
2481 the set of watchpoints, and, as a consequence, GDB changes the
2482 debug registers in the inferior. To avoid reading back a stale
2483 stopped-data-address when that happens, we cache in LP the fact
2484 that a watchpoint trapped, and the corresponding data address, as
2485 soon as we see LP stop with a SIGTRAP. If GDB changes the debug
2486 registers meanwhile, we have the cached data we can rely on. */
2489 save_sigtrap (struct lwp_info *lp)
2491 struct cleanup *old_chain;
2493 if (linux_ops->to_stopped_by_watchpoint == NULL)
2495 lp->stopped_by_watchpoint = 0;
2499 old_chain = save_inferior_ptid ();
2500 inferior_ptid = lp->ptid;
2502 lp->stopped_by_watchpoint = linux_ops->to_stopped_by_watchpoint (linux_ops);
2504 if (lp->stopped_by_watchpoint)
2506 if (linux_ops->to_stopped_data_address != NULL)
2507 lp->stopped_data_address_p =
2508 linux_ops->to_stopped_data_address (¤t_target,
2509 &lp->stopped_data_address);
2511 lp->stopped_data_address_p = 0;
2514 do_cleanups (old_chain);
2517 /* See save_sigtrap. */
2520 linux_nat_stopped_by_watchpoint (struct target_ops *ops)
2522 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2524 gdb_assert (lp != NULL);
2526 return lp->stopped_by_watchpoint;
2530 linux_nat_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
2532 struct lwp_info *lp = find_lwp_pid (inferior_ptid);
2534 gdb_assert (lp != NULL);
2536 *addr_p = lp->stopped_data_address;
2538 return lp->stopped_data_address_p;
2541 /* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
2544 sigtrap_is_event (int status)
2546 return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
2549 /* SIGTRAP-like events recognizer. */
2551 static int (*linux_nat_status_is_event) (int status) = sigtrap_is_event;
2553 /* Check for SIGTRAP-like events in LP. */
2556 linux_nat_lp_status_is_event (struct lwp_info *lp)
2558 /* We check for lp->waitstatus in addition to lp->status, because we can
2559 have pending process exits recorded in lp->status
2560 and W_EXITCODE(0,0) == 0. We should probably have an additional
2561 lp->status_p flag. */
2563 return (lp->waitstatus.kind == TARGET_WAITKIND_IGNORE
2564 && linux_nat_status_is_event (lp->status));
2567 /* Set alternative SIGTRAP-like events recognizer. If
2568 breakpoint_inserted_here_p there then gdbarch_decr_pc_after_break will be
2572 linux_nat_set_status_is_event (struct target_ops *t,
2573 int (*status_is_event) (int status))
2575 linux_nat_status_is_event = status_is_event;
2578 /* Wait until LP is stopped. */
2581 stop_wait_callback (struct lwp_info *lp, void *data)
2583 struct inferior *inf = find_inferior_pid (ptid_get_pid (lp->ptid));
2585 /* If this is a vfork parent, bail out, it is not going to report
2586 any SIGSTOP until the vfork is done with. */
2587 if (inf->vfork_child != NULL)
2594 status = wait_lwp (lp);
2598 if (lp->ignore_sigint && WIFSTOPPED (status)
2599 && WSTOPSIG (status) == SIGINT)
2601 lp->ignore_sigint = 0;
2604 ptrace (PTRACE_CONT, ptid_get_lwp (lp->ptid), 0, 0);
2606 if (debug_linux_nat)
2607 fprintf_unfiltered (gdb_stdlog,
2608 "PTRACE_CONT %s, 0, 0 (%s) "
2609 "(discarding SIGINT)\n",
2610 target_pid_to_str (lp->ptid),
2611 errno ? safe_strerror (errno) : "OK");
2613 return stop_wait_callback (lp, NULL);
2616 maybe_clear_ignore_sigint (lp);
2618 if (WSTOPSIG (status) != SIGSTOP)
2620 /* The thread was stopped with a signal other than SIGSTOP. */
2624 if (debug_linux_nat)
2625 fprintf_unfiltered (gdb_stdlog,
2626 "SWC: Pending event %s in %s\n",
2627 status_to_str ((int) status),
2628 target_pid_to_str (lp->ptid));
2630 /* Save the sigtrap event. */
2631 lp->status = status;
2632 gdb_assert (lp->signalled);
2636 /* We caught the SIGSTOP that we intended to catch, so
2637 there's no SIGSTOP pending. */
2639 if (debug_linux_nat)
2640 fprintf_unfiltered (gdb_stdlog,
2641 "SWC: Delayed SIGSTOP caught for %s.\n",
2642 target_pid_to_str (lp->ptid));
2644 /* Reset SIGNALLED only after the stop_wait_callback call
2645 above as it does gdb_assert on SIGNALLED. */
2653 /* Return non-zero if LP has a wait status pending. */
2656 status_callback (struct lwp_info *lp, void *data)
2658 /* Only report a pending wait status if we pretend that this has
2659 indeed been resumed. */
2663 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2665 /* A ptrace event, like PTRACE_FORK|VFORK|EXEC, syscall event,
2666 or a pending process exit. Note that `W_EXITCODE(0,0) ==
2667 0', so a clean process exit can not be stored pending in
2668 lp->status, it is indistinguishable from
2669 no-pending-status. */
2673 if (lp->status != 0)
2679 /* Return non-zero if LP isn't stopped. */
2682 running_callback (struct lwp_info *lp, void *data)
2684 return (!lp->stopped
2685 || ((lp->status != 0
2686 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
2690 /* Count the LWP's that have had events. */
2693 count_events_callback (struct lwp_info *lp, void *data)
2697 gdb_assert (count != NULL);
2699 /* Count only resumed LWPs that have a SIGTRAP event pending. */
2700 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2706 /* Select the LWP (if any) that is currently being single-stepped. */
2709 select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
2711 if (lp->last_resume_kind == resume_step
2718 /* Select the Nth LWP that has had a SIGTRAP event. */
2721 select_event_lwp_callback (struct lwp_info *lp, void *data)
2723 int *selector = data;
2725 gdb_assert (selector != NULL);
2727 /* Select only resumed LWPs that have a SIGTRAP event pending. */
2728 if (lp->resumed && linux_nat_lp_status_is_event (lp))
2729 if ((*selector)-- == 0)
2736 cancel_breakpoint (struct lwp_info *lp)
2738 /* Arrange for a breakpoint to be hit again later. We don't keep
2739 the SIGTRAP status and don't forward the SIGTRAP signal to the
2740 LWP. We will handle the current event, eventually we will resume
2741 this LWP, and this breakpoint will trap again.
2743 If we do not do this, then we run the risk that the user will
2744 delete or disable the breakpoint, but the LWP will have already
2747 struct regcache *regcache = get_thread_regcache (lp->ptid);
2748 struct gdbarch *gdbarch = get_regcache_arch (regcache);
2751 pc = regcache_read_pc (regcache) - target_decr_pc_after_break (gdbarch);
2752 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
2754 if (debug_linux_nat)
2755 fprintf_unfiltered (gdb_stdlog,
2756 "CB: Push back breakpoint for %s\n",
2757 target_pid_to_str (lp->ptid));
2759 /* Back up the PC if necessary. */
2760 if (target_decr_pc_after_break (gdbarch))
2761 regcache_write_pc (regcache, pc);
2769 cancel_breakpoints_callback (struct lwp_info *lp, void *data)
2771 struct lwp_info *event_lp = data;
2773 /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
2777 /* If a LWP other than the LWP that we're reporting an event for has
2778 hit a GDB breakpoint (as opposed to some random trap signal),
2779 then just arrange for it to hit it again later. We don't keep
2780 the SIGTRAP status and don't forward the SIGTRAP signal to the
2781 LWP. We will handle the current event, eventually we will resume
2782 all LWPs, and this one will get its breakpoint trap again.
2784 If we do not do this, then we run the risk that the user will
2785 delete or disable the breakpoint, but the LWP will have already
2788 if (linux_nat_lp_status_is_event (lp)
2789 && cancel_breakpoint (lp))
2790 /* Throw away the SIGTRAP. */
2796 /* Select one LWP out of those that have events pending. */
2799 select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
2802 int random_selector;
2803 struct lwp_info *event_lp;
2805 /* Record the wait status for the original LWP. */
2806 (*orig_lp)->status = *status;
2808 /* Give preference to any LWP that is being single-stepped. */
2809 event_lp = iterate_over_lwps (filter,
2810 select_singlestep_lwp_callback, NULL);
2811 if (event_lp != NULL)
2813 if (debug_linux_nat)
2814 fprintf_unfiltered (gdb_stdlog,
2815 "SEL: Select single-step %s\n",
2816 target_pid_to_str (event_lp->ptid));
2820 /* No single-stepping LWP. Select one at random, out of those
2821 which have had SIGTRAP events. */
2823 /* First see how many SIGTRAP events we have. */
2824 iterate_over_lwps (filter, count_events_callback, &num_events);
2826 /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
2827 random_selector = (int)
2828 ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
2830 if (debug_linux_nat && num_events > 1)
2831 fprintf_unfiltered (gdb_stdlog,
2832 "SEL: Found %d SIGTRAP events, selecting #%d\n",
2833 num_events, random_selector);
2835 event_lp = iterate_over_lwps (filter,
2836 select_event_lwp_callback,
2840 if (event_lp != NULL)
2842 /* Switch the event LWP. */
2843 *orig_lp = event_lp;
2844 *status = event_lp->status;
2847 /* Flush the wait status for the event LWP. */
2848 (*orig_lp)->status = 0;
2851 /* Return non-zero if LP has been resumed. */
2854 resumed_callback (struct lwp_info *lp, void *data)
2859 /* Stop an active thread, verify it still exists, then resume it. If
2860 the thread ends up with a pending status, then it is not resumed,
2861 and *DATA (really a pointer to int), is set. */
2864 stop_and_resume_callback (struct lwp_info *lp, void *data)
2866 int *new_pending_p = data;
2870 ptid_t ptid = lp->ptid;
2872 stop_callback (lp, NULL);
2873 stop_wait_callback (lp, NULL);
2875 /* Resume if the lwp still exists, and the core wanted it
2877 lp = find_lwp_pid (ptid);
2880 if (lp->last_resume_kind == resume_stop
2883 /* The core wanted the LWP to stop. Even if it stopped
2884 cleanly (with SIGSTOP), leave the event pending. */
2885 if (debug_linux_nat)
2886 fprintf_unfiltered (gdb_stdlog,
2887 "SARC: core wanted LWP %ld stopped "
2888 "(leaving SIGSTOP pending)\n",
2889 ptid_get_lwp (lp->ptid));
2890 lp->status = W_STOPCODE (SIGSTOP);
2893 if (lp->status == 0)
2895 if (debug_linux_nat)
2896 fprintf_unfiltered (gdb_stdlog,
2897 "SARC: re-resuming LWP %ld\n",
2898 ptid_get_lwp (lp->ptid));
2899 resume_lwp (lp, lp->step, GDB_SIGNAL_0);
2903 if (debug_linux_nat)
2904 fprintf_unfiltered (gdb_stdlog,
2905 "SARC: not re-resuming LWP %ld "
2907 ptid_get_lwp (lp->ptid));
2916 /* Check if we should go on and pass this event to common code.
2917 Return the affected lwp if we are, or NULL otherwise. If we stop
2918 all lwps temporarily, we may end up with new pending events in some
2919 other lwp. In that case set *NEW_PENDING_P to true. */
2921 static struct lwp_info *
2922 linux_nat_filter_event (int lwpid, int status, int *new_pending_p)
2924 struct lwp_info *lp;
2925 int event = linux_ptrace_get_extended_event (status);
2929 lp = find_lwp_pid (pid_to_ptid (lwpid));
2931 /* Check for stop events reported by a process we didn't already
2932 know about - anything not already in our LWP list.
2934 If we're expecting to receive stopped processes after
2935 fork, vfork, and clone events, then we'll just add the
2936 new one to our list and go back to waiting for the event
2937 to be reported - the stopped process might be returned
2938 from waitpid before or after the event is.
2940 But note the case of a non-leader thread exec'ing after the
2941 leader having exited, and gone from our lists. The non-leader
2942 thread changes its tid to the tgid. */
2944 if (WIFSTOPPED (status) && lp == NULL
2945 && (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC))
2947 /* A multi-thread exec after we had seen the leader exiting. */
2948 if (debug_linux_nat)
2949 fprintf_unfiltered (gdb_stdlog,
2950 "LLW: Re-adding thread group leader LWP %d.\n",
2953 lp = add_lwp (ptid_build (lwpid, lwpid, 0));
2956 add_thread (lp->ptid);
2959 if (WIFSTOPPED (status) && !lp)
2961 add_to_pid_list (&stopped_pids, lwpid, status);
2965 /* Make sure we don't report an event for the exit of an LWP not in
2966 our list, i.e. not part of the current process. This can happen
2967 if we detach from a program we originally forked and then it
2969 if (!WIFSTOPPED (status) && !lp)
2972 /* This LWP is stopped now. (And if dead, this prevents it from
2973 ever being continued.) */
2976 /* Handle GNU/Linux's syscall SIGTRAPs. */
2977 if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
2979 /* No longer need the sysgood bit. The ptrace event ends up
2980 recorded in lp->waitstatus if we care for it. We can carry
2981 on handling the event like a regular SIGTRAP from here
2983 status = W_STOPCODE (SIGTRAP);
2984 if (linux_handle_syscall_trap (lp, 0))
2988 /* Handle GNU/Linux's extended waitstatus for trace events. */
2989 if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
2990 && linux_is_extended_waitstatus (status))
2992 if (debug_linux_nat)
2993 fprintf_unfiltered (gdb_stdlog,
2994 "LLW: Handling extended status 0x%06x\n",
2996 if (linux_handle_extended_wait (lp, status, 0))
3000 if (linux_nat_status_is_event (status))
3003 /* Check if the thread has exited. */
3004 if ((WIFEXITED (status) || WIFSIGNALED (status))
3005 && num_lwps (ptid_get_pid (lp->ptid)) > 1)
3007 /* If this is the main thread, we must stop all threads and verify
3008 if they are still alive. This is because in the nptl thread model
3009 on Linux 2.4, there is no signal issued for exiting LWPs
3010 other than the main thread. We only get the main thread exit
3011 signal once all child threads have already exited. If we
3012 stop all the threads and use the stop_wait_callback to check
3013 if they have exited we can determine whether this signal
3014 should be ignored or whether it means the end of the debugged
3015 application, regardless of which threading model is being
3017 if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid))
3019 iterate_over_lwps (pid_to_ptid (ptid_get_pid (lp->ptid)),
3020 stop_and_resume_callback, new_pending_p);
3023 if (debug_linux_nat)
3024 fprintf_unfiltered (gdb_stdlog,
3025 "LLW: %s exited.\n",
3026 target_pid_to_str (lp->ptid));
3028 if (num_lwps (ptid_get_pid (lp->ptid)) > 1)
3030 /* If there is at least one more LWP, then the exit signal
3031 was not the end of the debugged application and should be
3038 /* Check if the current LWP has previously exited. In the nptl
3039 thread model, LWPs other than the main thread do not issue
3040 signals when they exit so we must check whenever the thread has
3041 stopped. A similar check is made in stop_wait_callback(). */
3042 if (num_lwps (ptid_get_pid (lp->ptid)) > 1 && !linux_thread_alive (lp->ptid))
3044 ptid_t ptid = pid_to_ptid (ptid_get_pid (lp->ptid));
3046 if (debug_linux_nat)
3047 fprintf_unfiltered (gdb_stdlog,
3048 "LLW: %s exited.\n",
3049 target_pid_to_str (lp->ptid));
3053 /* Make sure there is at least one thread running. */
3054 gdb_assert (iterate_over_lwps (ptid, running_callback, NULL));
3056 /* Discard the event. */
3060 /* Make sure we don't report a SIGSTOP that we sent ourselves in
3061 an attempt to stop an LWP. */
3063 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
3065 if (debug_linux_nat)
3066 fprintf_unfiltered (gdb_stdlog,
3067 "LLW: Delayed SIGSTOP caught for %s.\n",
3068 target_pid_to_str (lp->ptid));
3072 if (lp->last_resume_kind != resume_stop)
3074 /* This is a delayed SIGSTOP. */
3076 registers_changed ();
3078 if (linux_nat_prepare_to_resume != NULL)
3079 linux_nat_prepare_to_resume (lp);
3080 linux_ops->to_resume (linux_ops,
3081 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3082 lp->step, GDB_SIGNAL_0);
3083 if (debug_linux_nat)
3084 fprintf_unfiltered (gdb_stdlog,
3085 "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
3087 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3088 target_pid_to_str (lp->ptid));
3091 gdb_assert (lp->resumed);
3093 /* Discard the event. */
3098 /* Make sure we don't report a SIGINT that we have already displayed
3099 for another thread. */
3100 if (lp->ignore_sigint
3101 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
3103 if (debug_linux_nat)
3104 fprintf_unfiltered (gdb_stdlog,
3105 "LLW: Delayed SIGINT caught for %s.\n",
3106 target_pid_to_str (lp->ptid));
3108 /* This is a delayed SIGINT. */
3109 lp->ignore_sigint = 0;
3111 registers_changed ();
3112 if (linux_nat_prepare_to_resume != NULL)
3113 linux_nat_prepare_to_resume (lp);
3114 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3115 lp->step, GDB_SIGNAL_0);
3116 if (debug_linux_nat)
3117 fprintf_unfiltered (gdb_stdlog,
3118 "LLW: %s %s, 0, 0 (discard SIGINT)\n",
3120 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3121 target_pid_to_str (lp->ptid));
3124 gdb_assert (lp->resumed);
3126 /* Discard the event. */
3130 /* An interesting event. */
3132 lp->status = status;
3136 /* Detect zombie thread group leaders, and "exit" them. We can't reap
3137 their exits until all other threads in the group have exited. */
3140 check_zombie_leaders (void)
3142 struct inferior *inf;
3146 struct lwp_info *leader_lp;
3151 leader_lp = find_lwp_pid (pid_to_ptid (inf->pid));
3152 if (leader_lp != NULL
3153 /* Check if there are other threads in the group, as we may
3154 have raced with the inferior simply exiting. */
3155 && num_lwps (inf->pid) > 1
3156 && linux_proc_pid_is_zombie (inf->pid))
3158 if (debug_linux_nat)
3159 fprintf_unfiltered (gdb_stdlog,
3160 "CZL: Thread group leader %d zombie "
3161 "(it exited, or another thread execd).\n",
3164 /* A leader zombie can mean one of two things:
3166 - It exited, and there's an exit status pending
3167 available, or only the leader exited (not the whole
3168 program). In the latter case, we can't waitpid the
3169 leader's exit status until all other threads are gone.
3171 - There are 3 or more threads in the group, and a thread
3172 other than the leader exec'd. On an exec, the Linux
3173 kernel destroys all other threads (except the execing
3174 one) in the thread group, and resets the execing thread's
3175 tid to the tgid. No exit notification is sent for the
3176 execing thread -- from the ptracer's perspective, it
3177 appears as though the execing thread just vanishes.
3178 Until we reap all other threads except the leader and the
3179 execing thread, the leader will be zombie, and the
3180 execing thread will be in `D (disc sleep)'. As soon as
3181 all other threads are reaped, the execing thread changes
3182 it's tid to the tgid, and the previous (zombie) leader
3183 vanishes, giving place to the "new" leader. We could try
3184 distinguishing the exit and exec cases, by waiting once
3185 more, and seeing if something comes out, but it doesn't
3186 sound useful. The previous leader _does_ go away, and
3187 we'll re-add the new one once we see the exec event
3188 (which is just the same as what would happen if the
3189 previous leader did exit voluntarily before some other
3192 if (debug_linux_nat)
3193 fprintf_unfiltered (gdb_stdlog,
3194 "CZL: Thread group leader %d vanished.\n",
3196 exit_lwp (leader_lp);
3202 linux_nat_wait_1 (struct target_ops *ops,
3203 ptid_t ptid, struct target_waitstatus *ourstatus,
3206 static sigset_t prev_mask;
3207 enum resume_kind last_resume_kind;
3208 struct lwp_info *lp;
3211 if (debug_linux_nat)
3212 fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
3214 /* The first time we get here after starting a new inferior, we may
3215 not have added it to the LWP list yet - this is the earliest
3216 moment at which we know its PID. */
3217 if (ptid_is_pid (inferior_ptid))
3219 /* Upgrade the main thread's ptid. */
3220 thread_change_ptid (inferior_ptid,
3221 ptid_build (ptid_get_pid (inferior_ptid),
3222 ptid_get_pid (inferior_ptid), 0));
3224 lp = add_initial_lwp (inferior_ptid);
3228 /* Make sure SIGCHLD is blocked until the sigsuspend below. */
3229 block_child_signals (&prev_mask);
3235 /* First check if there is a LWP with a wait status pending. */
3236 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3238 /* Any LWP in the PTID group that's been resumed will do. */
3239 lp = iterate_over_lwps (ptid, status_callback, NULL);
3242 if (debug_linux_nat && lp->status)
3243 fprintf_unfiltered (gdb_stdlog,
3244 "LLW: Using pending wait status %s for %s.\n",
3245 status_to_str (lp->status),
3246 target_pid_to_str (lp->ptid));
3249 else if (ptid_lwp_p (ptid))
3251 if (debug_linux_nat)
3252 fprintf_unfiltered (gdb_stdlog,
3253 "LLW: Waiting for specific LWP %s.\n",
3254 target_pid_to_str (ptid));
3256 /* We have a specific LWP to check. */
3257 lp = find_lwp_pid (ptid);
3260 if (debug_linux_nat && lp->status)
3261 fprintf_unfiltered (gdb_stdlog,
3262 "LLW: Using pending wait status %s for %s.\n",
3263 status_to_str (lp->status),
3264 target_pid_to_str (lp->ptid));
3266 /* We check for lp->waitstatus in addition to lp->status,
3267 because we can have pending process exits recorded in
3268 lp->status and W_EXITCODE(0,0) == 0. We should probably have
3269 an additional lp->status_p flag. */
3270 if (lp->status == 0 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3274 if (!target_can_async_p ())
3276 /* Causes SIGINT to be passed on to the attached process. */
3280 /* But if we don't find a pending event, we'll have to wait. */
3286 /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
3289 - If the thread group leader exits while other threads in the
3290 thread group still exist, waitpid(TGID, ...) hangs. That
3291 waitpid won't return an exit status until the other threads
3292 in the group are reapped.
3294 - When a non-leader thread execs, that thread just vanishes
3295 without reporting an exit (so we'd hang if we waited for it
3296 explicitly in that case). The exec event is reported to
3300 lwpid = my_waitpid (-1, &status, __WCLONE | WNOHANG);
3301 if (lwpid == 0 || (lwpid == -1 && errno == ECHILD))
3302 lwpid = my_waitpid (-1, &status, WNOHANG);
3304 if (debug_linux_nat)
3305 fprintf_unfiltered (gdb_stdlog,
3306 "LNW: waitpid(-1, ...) returned %d, %s\n",
3307 lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
3311 /* If this is true, then we paused LWPs momentarily, and may
3312 now have pending events to handle. */
3315 if (debug_linux_nat)
3317 fprintf_unfiltered (gdb_stdlog,
3318 "LLW: waitpid %ld received %s\n",
3319 (long) lwpid, status_to_str (status));
3322 lp = linux_nat_filter_event (lwpid, status, &new_pending);
3324 /* STATUS is now no longer valid, use LP->STATUS instead. */
3327 if (lp && !ptid_match (lp->ptid, ptid))
3329 gdb_assert (lp->resumed);
3331 if (debug_linux_nat)
3332 fprintf_unfiltered (gdb_stdlog,
3333 "LWP %ld got an event %06x, "
3334 "leaving pending.\n",
3335 ptid_get_lwp (lp->ptid), lp->status);
3337 if (WIFSTOPPED (lp->status))
3339 if (WSTOPSIG (lp->status) != SIGSTOP)
3341 /* Cancel breakpoint hits. The breakpoint may
3342 be removed before we fetch events from this
3343 process to report to the core. It is best
3344 not to assume the moribund breakpoints
3345 heuristic always handles these cases --- it
3346 could be too many events go through to the
3347 core before this one is handled. All-stop
3348 always cancels breakpoint hits in all
3351 && linux_nat_lp_status_is_event (lp)
3352 && cancel_breakpoint (lp))
3354 /* Throw away the SIGTRAP. */
3357 if (debug_linux_nat)
3358 fprintf_unfiltered (gdb_stdlog,
3359 "LLW: LWP %ld hit a "
3361 "waiting for another "
3364 ptid_get_lwp (lp->ptid));
3370 else if (WIFEXITED (lp->status) || WIFSIGNALED (lp->status))
3372 if (debug_linux_nat)
3373 fprintf_unfiltered (gdb_stdlog,
3374 "Process %ld exited while stopping "
3376 ptid_get_lwp (lp->ptid));
3378 /* This was the last lwp in the process. Since
3379 events are serialized to GDB core, and we can't
3380 report this one right now, but GDB core and the
3381 other target layers will want to be notified
3382 about the exit code/signal, leave the status
3383 pending for the next time we're able to report
3386 /* Dead LWP's aren't expected to reported a pending
3390 /* Store the pending event in the waitstatus as
3391 well, because W_EXITCODE(0,0) == 0. */
3392 store_waitstatus (&lp->waitstatus, lp->status);
3401 /* Some LWP now has a pending event. Go all the way
3402 back to check it. */
3408 /* We got an event to report to the core. */
3412 /* Retry until nothing comes out of waitpid. A single
3413 SIGCHLD can indicate more than one child stopped. */
3417 /* Check for zombie thread group leaders. Those can't be reaped
3418 until all other threads in the thread group are. */
3419 check_zombie_leaders ();
3421 /* If there are no resumed children left, bail. We'd be stuck
3422 forever in the sigsuspend call below otherwise. */
3423 if (iterate_over_lwps (ptid, resumed_callback, NULL) == NULL)
3425 if (debug_linux_nat)
3426 fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
3428 ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
3430 if (!target_can_async_p ())
3431 clear_sigint_trap ();
3433 restore_child_signals_mask (&prev_mask);
3434 return minus_one_ptid;
3437 /* No interesting event to report to the core. */
3439 if (target_options & TARGET_WNOHANG)
3441 if (debug_linux_nat)
3442 fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
3444 ourstatus->kind = TARGET_WAITKIND_IGNORE;
3445 restore_child_signals_mask (&prev_mask);
3446 return minus_one_ptid;
3449 /* We shouldn't end up here unless we want to try again. */
3450 gdb_assert (lp == NULL);
3452 /* Block until we get an event reported with SIGCHLD. */
3453 if (debug_linux_nat)
3454 fprintf_unfiltered (gdb_stdlog, "LNW: about to sigsuspend\n");
3455 sigsuspend (&suspend_mask);
3458 if (!target_can_async_p ())
3459 clear_sigint_trap ();
3463 status = lp->status;
3466 /* Don't report signals that GDB isn't interested in, such as
3467 signals that are neither printed nor stopped upon. Stopping all
3468 threads can be a bit time-consuming so if we want decent
3469 performance with heavily multi-threaded programs, especially when
3470 they're using a high frequency timer, we'd better avoid it if we
3473 if (WIFSTOPPED (status))
3475 enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
3477 /* When using hardware single-step, we need to report every signal.
3478 Otherwise, signals in pass_mask may be short-circuited. */
3480 && WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status)))
3482 /* FIMXE: kettenis/2001-06-06: Should we resume all threads
3483 here? It is not clear we should. GDB may not expect
3484 other threads to run. On the other hand, not resuming
3485 newly attached threads may cause an unwanted delay in
3486 getting them running. */
3487 registers_changed ();
3488 if (linux_nat_prepare_to_resume != NULL)
3489 linux_nat_prepare_to_resume (lp);
3490 linux_ops->to_resume (linux_ops,
3491 pid_to_ptid (ptid_get_lwp (lp->ptid)),
3493 if (debug_linux_nat)
3494 fprintf_unfiltered (gdb_stdlog,
3495 "LLW: %s %s, %s (preempt 'handle')\n",
3497 "PTRACE_SINGLESTEP" : "PTRACE_CONT",
3498 target_pid_to_str (lp->ptid),
3499 (signo != GDB_SIGNAL_0
3500 ? strsignal (gdb_signal_to_host (signo))
3508 /* Only do the below in all-stop, as we currently use SIGINT
3509 to implement target_stop (see linux_nat_stop) in
3511 if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
3513 /* If ^C/BREAK is typed at the tty/console, SIGINT gets
3514 forwarded to the entire process group, that is, all LWPs
3515 will receive it - unless they're using CLONE_THREAD to
3516 share signals. Since we only want to report it once, we
3517 mark it as ignored for all LWPs except this one. */
3518 iterate_over_lwps (pid_to_ptid (ptid_get_pid (ptid)),
3519 set_ignore_sigint, NULL);
3520 lp->ignore_sigint = 0;
3523 maybe_clear_ignore_sigint (lp);
3527 /* This LWP is stopped now. */
3530 if (debug_linux_nat)
3531 fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
3532 status_to_str (status), target_pid_to_str (lp->ptid));
3536 /* Now stop all other LWP's ... */
3537 iterate_over_lwps (minus_one_ptid, stop_callback, NULL);
3539 /* ... and wait until all of them have reported back that
3540 they're no longer running. */
3541 iterate_over_lwps (minus_one_ptid, stop_wait_callback, NULL);
3543 /* If we're not waiting for a specific LWP, choose an event LWP
3544 from among those that have had events. Giving equal priority
3545 to all LWPs that have had events helps prevent
3547 if (ptid_equal (ptid, minus_one_ptid) || ptid_is_pid (ptid))
3548 select_event_lwp (ptid, &lp, &status);
3550 /* Now that we've selected our final event LWP, cancel any
3551 breakpoints in other LWPs that have hit a GDB breakpoint.
3552 See the comment in cancel_breakpoints_callback to find out
3554 iterate_over_lwps (minus_one_ptid, cancel_breakpoints_callback, lp);
3556 /* We'll need this to determine whether to report a SIGSTOP as
3557 TARGET_WAITKIND_0. Need to take a copy because
3558 resume_clear_callback clears it. */
3559 last_resume_kind = lp->last_resume_kind;
3561 /* In all-stop, from the core's perspective, all LWPs are now
3562 stopped until a new resume action is sent over. */
3563 iterate_over_lwps (minus_one_ptid, resume_clear_callback, NULL);
3568 last_resume_kind = lp->last_resume_kind;
3569 resume_clear_callback (lp, NULL);
3572 if (linux_nat_status_is_event (status))
3574 if (debug_linux_nat)
3575 fprintf_unfiltered (gdb_stdlog,
3576 "LLW: trap ptid is %s.\n",
3577 target_pid_to_str (lp->ptid));
3580 if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
3582 *ourstatus = lp->waitstatus;
3583 lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
3586 store_waitstatus (ourstatus, status);
3588 if (debug_linux_nat)
3589 fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
3591 restore_child_signals_mask (&prev_mask);
3593 if (last_resume_kind == resume_stop
3594 && ourstatus->kind == TARGET_WAITKIND_STOPPED
3595 && WSTOPSIG (status) == SIGSTOP)
3597 /* A thread that has been requested to stop by GDB with
3598 target_stop, and it stopped cleanly, so report as SIG0. The
3599 use of SIGSTOP is an implementation detail. */
3600 ourstatus->value.sig = GDB_SIGNAL_0;
3603 if (ourstatus->kind == TARGET_WAITKIND_EXITED
3604 || ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
3607 lp->core = linux_common_core_of_thread (lp->ptid);
3612 /* Resume LWPs that are currently stopped without any pending status
3613 to report, but are resumed from the core's perspective. */
3616 resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
3618 ptid_t *wait_ptid_p = data;
3623 && lp->waitstatus.kind == TARGET_WAITKIND_IGNORE)
3625 struct regcache *regcache = get_thread_regcache (lp->ptid);
3626 struct gdbarch *gdbarch = get_regcache_arch (regcache);
3627 CORE_ADDR pc = regcache_read_pc (regcache);
3629 gdb_assert (is_executing (lp->ptid));
3631 /* Don't bother if there's a breakpoint at PC that we'd hit
3632 immediately, and we're not waiting for this LWP. */
3633 if (!ptid_match (lp->ptid, *wait_ptid_p))
3635 if (breakpoint_inserted_here_p (get_regcache_aspace (regcache), pc))
3639 if (debug_linux_nat)
3640 fprintf_unfiltered (gdb_stdlog,
3641 "RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n",
3642 target_pid_to_str (lp->ptid),
3643 paddress (gdbarch, pc),
3646 registers_changed ();
3647 if (linux_nat_prepare_to_resume != NULL)
3648 linux_nat_prepare_to_resume (lp);
3649 linux_ops->to_resume (linux_ops, pid_to_ptid (ptid_get_lwp (lp->ptid)),
3650 lp->step, GDB_SIGNAL_0);
3652 lp->stopped_by_watchpoint = 0;
3659 linux_nat_wait (struct target_ops *ops,
3660 ptid_t ptid, struct target_waitstatus *ourstatus,
3665 if (debug_linux_nat)
3667 char *options_string;
3669 options_string = target_options_to_string (target_options);
3670 fprintf_unfiltered (gdb_stdlog,
3671 "linux_nat_wait: [%s], [%s]\n",
3672 target_pid_to_str (ptid),
3674 xfree (options_string);
3677 /* Flush the async file first. */
3678 if (target_can_async_p ())
3679 async_file_flush ();
3681 /* Resume LWPs that are currently stopped without any pending status
3682 to report, but are resumed from the core's perspective. LWPs get
3683 in this state if we find them stopping at a time we're not
3684 interested in reporting the event (target_wait on a
3685 specific_process, for example, see linux_nat_wait_1), and
3686 meanwhile the event became uninteresting. Don't bother resuming
3687 LWPs we're not going to wait for if they'd stop immediately. */
3689 iterate_over_lwps (minus_one_ptid, resume_stopped_resumed_lwps, &ptid);
3691 event_ptid = linux_nat_wait_1 (ops, ptid, ourstatus, target_options);
3693 /* If we requested any event, and something came out, assume there
3694 may be more. If we requested a specific lwp or process, also
3695 assume there may be more. */
3696 if (target_can_async_p ()
3697 && ((ourstatus->kind != TARGET_WAITKIND_IGNORE
3698 && ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
3699 || !ptid_equal (ptid, minus_one_ptid)))
3702 /* Get ready for the next event. */
3703 if (target_can_async_p ())
3704 target_async (inferior_event_handler, 0);
3710 kill_callback (struct lwp_info *lp, void *data)
3712 /* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
3715 kill_lwp (ptid_get_lwp (lp->ptid), SIGKILL);
3716 if (debug_linux_nat)
3718 int save_errno = errno;
3720 fprintf_unfiltered (gdb_stdlog,
3721 "KC: kill (SIGKILL) %s, 0, 0 (%s)\n",
3722 target_pid_to_str (lp->ptid),
3723 save_errno ? safe_strerror (save_errno) : "OK");
3726 /* Some kernels ignore even SIGKILL for processes under ptrace. */
3729 ptrace (PTRACE_KILL, ptid_get_lwp (lp->ptid), 0, 0);
3730 if (debug_linux_nat)
3732 int save_errno = errno;
3734 fprintf_unfiltered (gdb_stdlog,
3735 "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
3736 target_pid_to_str (lp->ptid),
3737 save_errno ? safe_strerror (save_errno) : "OK");
3744 kill_wait_callback (struct lwp_info *lp, void *data)
3748 /* We must make sure that there are no pending events (delayed
3749 SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
3750 program doesn't interfere with any following debugging session. */
3752 /* For cloned processes we must check both with __WCLONE and
3753 without, since the exit status of a cloned process isn't reported
3759 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, __WCLONE);
3760 if (pid != (pid_t) -1)
3762 if (debug_linux_nat)
3763 fprintf_unfiltered (gdb_stdlog,
3764 "KWC: wait %s received unknown.\n",
3765 target_pid_to_str (lp->ptid));
3766 /* The Linux kernel sometimes fails to kill a thread
3767 completely after PTRACE_KILL; that goes from the stop
3768 point in do_fork out to the one in
3769 get_signal_to_deliever and waits again. So kill it
3771 kill_callback (lp, NULL);
3774 while (pid == ptid_get_lwp (lp->ptid));
3776 gdb_assert (pid == -1 && errno == ECHILD);
3781 pid = my_waitpid (ptid_get_lwp (lp->ptid), NULL, 0);
3782 if (pid != (pid_t) -1)
3784 if (debug_linux_nat)
3785 fprintf_unfiltered (gdb_stdlog,
3786 "KWC: wait %s received unk.\n",
3787 target_pid_to_str (lp->ptid));
3788 /* See the call to kill_callback above. */
3789 kill_callback (lp, NULL);
3792 while (pid == ptid_get_lwp (lp->ptid));
3794 gdb_assert (pid == -1 && errno == ECHILD);
3799 linux_nat_kill (struct target_ops *ops)
3801 struct target_waitstatus last;
3805 /* If we're stopped while forking and we haven't followed yet,
3806 kill the other task. We need to do this first because the
3807 parent will be sleeping if this is a vfork. */
3809 get_last_target_status (&last_ptid, &last);
3811 if (last.kind == TARGET_WAITKIND_FORKED
3812 || last.kind == TARGET_WAITKIND_VFORKED)
3814 ptrace (PT_KILL, ptid_get_pid (last.value.related_pid), 0, 0);
3817 /* Let the arch-specific native code know this process is
3819 linux_nat_forget_process (ptid_get_pid (last.value.related_pid));
3822 if (forks_exist_p ())
3823 linux_fork_killall ();
3826 ptid_t ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
3828 /* Stop all threads before killing them, since ptrace requires
3829 that the thread is stopped to sucessfully PTRACE_KILL. */
3830 iterate_over_lwps (ptid, stop_callback, NULL);
3831 /* ... and wait until all of them have reported back that
3832 they're no longer running. */
3833 iterate_over_lwps (ptid, stop_wait_callback, NULL);
3835 /* Kill all LWP's ... */
3836 iterate_over_lwps (ptid, kill_callback, NULL);
3838 /* ... and wait until we've flushed all events. */
3839 iterate_over_lwps (ptid, kill_wait_callback, NULL);
3842 target_mourn_inferior ();
3846 linux_nat_mourn_inferior (struct target_ops *ops)
3848 int pid = ptid_get_pid (inferior_ptid);
3850 purge_lwp_list (pid);
3852 if (! forks_exist_p ())
3853 /* Normal case, no other forks available. */
3854 linux_ops->to_mourn_inferior (ops);
3856 /* Multi-fork case. The current inferior_ptid has exited, but
3857 there are other viable forks to debug. Delete the exiting
3858 one and context-switch to the first available. */
3859 linux_fork_mourn_inferior ();
3861 /* Let the arch-specific native code know this process is gone. */
3862 linux_nat_forget_process (pid);
3865 /* Convert a native/host siginfo object, into/from the siginfo in the
3866 layout of the inferiors' architecture. */
3869 siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
3873 if (linux_nat_siginfo_fixup != NULL)
3874 done = linux_nat_siginfo_fixup (siginfo, inf_siginfo, direction);
3876 /* If there was no callback, or the callback didn't do anything,
3877 then just do a straight memcpy. */
3881 memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
3883 memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
3887 static enum target_xfer_status
3888 linux_xfer_siginfo (struct target_ops *ops, enum target_object object,
3889 const char *annex, gdb_byte *readbuf,
3890 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
3891 ULONGEST *xfered_len)
3895 gdb_byte inf_siginfo[sizeof (siginfo_t)];
3897 gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
3898 gdb_assert (readbuf || writebuf);
3900 pid = ptid_get_lwp (inferior_ptid);
3902 pid = ptid_get_pid (inferior_ptid);
3904 if (offset > sizeof (siginfo))
3905 return TARGET_XFER_E_IO;
3908 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3910 return TARGET_XFER_E_IO;
3912 /* When GDB is built as a 64-bit application, ptrace writes into
3913 SIGINFO an object with 64-bit layout. Since debugging a 32-bit
3914 inferior with a 64-bit GDB should look the same as debugging it
3915 with a 32-bit GDB, we need to convert it. GDB core always sees
3916 the converted layout, so any read/write will have to be done
3918 siginfo_fixup (&siginfo, inf_siginfo, 0);
3920 if (offset + len > sizeof (siginfo))
3921 len = sizeof (siginfo) - offset;
3923 if (readbuf != NULL)
3924 memcpy (readbuf, inf_siginfo + offset, len);
3927 memcpy (inf_siginfo + offset, writebuf, len);
3929 /* Convert back to ptrace layout before flushing it out. */
3930 siginfo_fixup (&siginfo, inf_siginfo, 1);
3933 ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
3935 return TARGET_XFER_E_IO;
3939 return TARGET_XFER_OK;
3942 static enum target_xfer_status
3943 linux_nat_xfer_partial (struct target_ops *ops, enum target_object object,
3944 const char *annex, gdb_byte *readbuf,
3945 const gdb_byte *writebuf,
3946 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
3948 struct cleanup *old_chain;
3949 enum target_xfer_status xfer;
3951 if (object == TARGET_OBJECT_SIGNAL_INFO)
3952 return linux_xfer_siginfo (ops, object, annex, readbuf, writebuf,
3953 offset, len, xfered_len);
3955 /* The target is connected but no live inferior is selected. Pass
3956 this request down to a lower stratum (e.g., the executable
3958 if (object == TARGET_OBJECT_MEMORY && ptid_equal (inferior_ptid, null_ptid))
3959 return TARGET_XFER_EOF;
3961 old_chain = save_inferior_ptid ();
3963 if (ptid_lwp_p (inferior_ptid))
3964 inferior_ptid = pid_to_ptid (ptid_get_lwp (inferior_ptid));
3966 xfer = linux_ops->to_xfer_partial (ops, object, annex, readbuf, writebuf,
3967 offset, len, xfered_len);
3969 do_cleanups (old_chain);
3974 linux_thread_alive (ptid_t ptid)
3978 gdb_assert (ptid_lwp_p (ptid));
3980 /* Send signal 0 instead of anything ptrace, because ptracing a
3981 running thread errors out claiming that the thread doesn't
3983 err = kill_lwp (ptid_get_lwp (ptid), 0);
3985 if (debug_linux_nat)
3986 fprintf_unfiltered (gdb_stdlog,
3987 "LLTA: KILL(SIG0) %s (%s)\n",
3988 target_pid_to_str (ptid),
3989 err ? safe_strerror (tmp_errno) : "OK");
3998 linux_nat_thread_alive (struct target_ops *ops, ptid_t ptid)
4000 return linux_thread_alive (ptid);
4004 linux_nat_pid_to_str (struct target_ops *ops, ptid_t ptid)
4006 static char buf[64];
4008 if (ptid_lwp_p (ptid)
4009 && (ptid_get_pid (ptid) != ptid_get_lwp (ptid)
4010 || num_lwps (ptid_get_pid (ptid)) > 1))
4012 snprintf (buf, sizeof (buf), "LWP %ld", ptid_get_lwp (ptid));
4016 return normal_pid_to_str (ptid);
4020 linux_nat_thread_name (struct target_ops *self, struct thread_info *thr)
4022 int pid = ptid_get_pid (thr->ptid);
4023 long lwp = ptid_get_lwp (thr->ptid);
4024 #define FORMAT "/proc/%d/task/%ld/comm"
4025 char buf[sizeof (FORMAT) + 30];
4027 char *result = NULL;
4029 snprintf (buf, sizeof (buf), FORMAT, pid, lwp);
4030 comm_file = gdb_fopen_cloexec (buf, "r");
4033 /* Not exported by the kernel, so we define it here. */
4035 static char line[COMM_LEN + 1];
4037 if (fgets (line, sizeof (line), comm_file))
4039 char *nl = strchr (line, '\n');
4056 /* Accepts an integer PID; Returns a string representing a file that
4057 can be opened to get the symbols for the child process. */
4060 linux_child_pid_to_exec_file (struct target_ops *self, int pid)
4062 static char buf[PATH_MAX];
4063 char name[PATH_MAX];
4065 xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
4066 memset (buf, 0, PATH_MAX);
4067 if (readlink (name, buf, PATH_MAX - 1) <= 0)
4073 /* Records the thread's register state for the corefile note
4077 linux_nat_collect_thread_registers (const struct regcache *regcache,
4078 ptid_t ptid, bfd *obfd,
4079 char *note_data, int *note_size,
4080 enum gdb_signal stop_signal)
4082 struct gdbarch *gdbarch = get_regcache_arch (regcache);
4083 const struct regset *regset;
4085 gdb_gregset_t gregs;
4086 gdb_fpregset_t fpregs;
4088 core_regset_p = gdbarch_regset_from_core_section_p (gdbarch);
4091 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg",
4093 != NULL && regset->collect_regset != NULL)
4094 regset->collect_regset (regset, regcache, -1, &gregs, sizeof (gregs));
4096 fill_gregset (regcache, &gregs, -1);
4098 note_data = (char *) elfcore_write_prstatus
4099 (obfd, note_data, note_size, ptid_get_lwp (ptid),
4100 gdb_signal_to_host (stop_signal), &gregs);
4103 && (regset = gdbarch_regset_from_core_section (gdbarch, ".reg2",
4105 != NULL && regset->collect_regset != NULL)
4106 regset->collect_regset (regset, regcache, -1, &fpregs, sizeof (fpregs));
4108 fill_fpregset (regcache, &fpregs, -1);
4110 note_data = (char *) elfcore_write_prfpreg (obfd, note_data, note_size,
4111 &fpregs, sizeof (fpregs));
4116 /* Fills the "to_make_corefile_note" target vector. Builds the note
4117 section for a corefile, and returns it in a malloc buffer. */
4120 linux_nat_make_corefile_notes (struct target_ops *self,
4121 bfd *obfd, int *note_size)
4123 /* FIXME: uweigand/2011-10-06: Once all GNU/Linux architectures have been
4124 converted to gdbarch_core_regset_sections, this function can go away. */
4125 return linux_make_corefile_notes (target_gdbarch (), obfd, note_size,
4126 linux_nat_collect_thread_registers);
4129 /* Implement the to_xfer_partial interface for memory reads using the /proc
4130 filesystem. Because we can use a single read() call for /proc, this
4131 can be much more efficient than banging away at PTRACE_PEEKTEXT,
4132 but it doesn't support writes. */
4134 static enum target_xfer_status
4135 linux_proc_xfer_partial (struct target_ops *ops, enum target_object object,
4136 const char *annex, gdb_byte *readbuf,
4137 const gdb_byte *writebuf,
4138 ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
4144 if (object != TARGET_OBJECT_MEMORY || !readbuf)
4147 /* Don't bother for one word. */
4148 if (len < 3 * sizeof (long))
4149 return TARGET_XFER_EOF;
4151 /* We could keep this file open and cache it - possibly one per
4152 thread. That requires some juggling, but is even faster. */
4153 xsnprintf (filename, sizeof filename, "/proc/%d/mem",
4154 ptid_get_pid (inferior_ptid));
4155 fd = gdb_open_cloexec (filename, O_RDONLY | O_LARGEFILE, 0);
4157 return TARGET_XFER_EOF;
4159 /* If pread64 is available, use it. It's faster if the kernel
4160 supports it (only one syscall), and it's 64-bit safe even on
4161 32-bit platforms (for instance, SPARC debugging a SPARC64
4164 if (pread64 (fd, readbuf, len, offset) != len)
4166 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf, len) != len)
4175 return TARGET_XFER_EOF;
4179 return TARGET_XFER_OK;
4184 /* Enumerate spufs IDs for process PID. */
4186 spu_enumerate_spu_ids (int pid, gdb_byte *buf, ULONGEST offset, ULONGEST len)
4188 enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
4190 LONGEST written = 0;
4193 struct dirent *entry;
4195 xsnprintf (path, sizeof path, "/proc/%d/fd", pid);
4196 dir = opendir (path);
4201 while ((entry = readdir (dir)) != NULL)
4207 fd = atoi (entry->d_name);
4211 xsnprintf (path, sizeof path, "/proc/%d/fd/%d", pid, fd);
4212 if (stat (path, &st) != 0)
4214 if (!S_ISDIR (st.st_mode))
4217 if (statfs (path, &stfs) != 0)
4219 if (stfs.f_type != SPUFS_MAGIC)
4222 if (pos >= offset && pos + 4 <= offset + len)
4224 store_unsigned_integer (buf + pos - offset, 4, byte_order, fd);
4234 /* Implement the to_xfer_partial interface for the TARGET_OBJECT_SPU
4235 object type, using the /proc file system. */
4237 static enum target_xfer_status
4238 linux_proc_xfer_spu (struct target_ops *ops, enum target_object object,
4239 const char *annex, gdb_byte *readbuf,
4240 const gdb_byte *writebuf,
4241 ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
4246 int pid = ptid_get_pid (inferior_ptid);
4251 return TARGET_XFER_E_IO;
4254 LONGEST l = spu_enumerate_spu_ids (pid, readbuf, offset, len);
4257 return TARGET_XFER_E_IO;
4259 return TARGET_XFER_EOF;
4262 *xfered_len = (ULONGEST) l;
4263 return TARGET_XFER_OK;
4268 xsnprintf (buf, sizeof buf, "/proc/%d/fd/%s", pid, annex);
4269 fd = gdb_open_cloexec (buf, writebuf? O_WRONLY : O_RDONLY, 0);
4271 return TARGET_XFER_E_IO;
4274 && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
4277 return TARGET_XFER_EOF;
4281 ret = write (fd, writebuf, (size_t) len);
4283 ret = read (fd, readbuf, (size_t) len);
4288 return TARGET_XFER_E_IO;
4290 return TARGET_XFER_EOF;
4293 *xfered_len = (ULONGEST) ret;
4294 return TARGET_XFER_OK;
4299 /* Parse LINE as a signal set and add its set bits to SIGS. */
4302 add_line_to_sigset (const char *line, sigset_t *sigs)
4304 int len = strlen (line) - 1;
4308 if (line[len] != '\n')
4309 error (_("Could not parse signal set: %s"), line);
4317 if (*p >= '0' && *p <= '9')
4319 else if (*p >= 'a' && *p <= 'f')
4320 digit = *p - 'a' + 10;
4322 error (_("Could not parse signal set: %s"), line);
4327 sigaddset (sigs, signum + 1);
4329 sigaddset (sigs, signum + 2);
4331 sigaddset (sigs, signum + 3);
4333 sigaddset (sigs, signum + 4);
4339 /* Find process PID's pending signals from /proc/pid/status and set
4343 linux_proc_pending_signals (int pid, sigset_t *pending,
4344 sigset_t *blocked, sigset_t *ignored)
4347 char buffer[PATH_MAX], fname[PATH_MAX];
4348 struct cleanup *cleanup;
4350 sigemptyset (pending);
4351 sigemptyset (blocked);
4352 sigemptyset (ignored);
4353 xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
4354 procfile = gdb_fopen_cloexec (fname, "r");
4355 if (procfile == NULL)
4356 error (_("Could not open %s"), fname);
4357 cleanup = make_cleanup_fclose (procfile);
4359 while (fgets (buffer, PATH_MAX, procfile) != NULL)
4361 /* Normal queued signals are on the SigPnd line in the status
4362 file. However, 2.6 kernels also have a "shared" pending
4363 queue for delivering signals to a thread group, so check for
4366 Unfortunately some Red Hat kernels include the shared pending
4367 queue but not the ShdPnd status field. */
4369 if (strncmp (buffer, "SigPnd:\t", 8) == 0)
4370 add_line_to_sigset (buffer + 8, pending);
4371 else if (strncmp (buffer, "ShdPnd:\t", 8) == 0)
4372 add_line_to_sigset (buffer + 8, pending);
4373 else if (strncmp (buffer, "SigBlk:\t", 8) == 0)
4374 add_line_to_sigset (buffer + 8, blocked);
4375 else if (strncmp (buffer, "SigIgn:\t", 8) == 0)
4376 add_line_to_sigset (buffer + 8, ignored);
4379 do_cleanups (cleanup);
4382 static enum target_xfer_status
4383 linux_nat_xfer_osdata (struct target_ops *ops, enum target_object object,
4384 const char *annex, gdb_byte *readbuf,
4385 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4386 ULONGEST *xfered_len)
4388 gdb_assert (object == TARGET_OBJECT_OSDATA);
4390 *xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
4391 if (*xfered_len == 0)
4392 return TARGET_XFER_EOF;
4394 return TARGET_XFER_OK;
4397 static enum target_xfer_status
4398 linux_xfer_partial (struct target_ops *ops, enum target_object object,
4399 const char *annex, gdb_byte *readbuf,
4400 const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
4401 ULONGEST *xfered_len)
4403 enum target_xfer_status xfer;
4405 if (object == TARGET_OBJECT_AUXV)
4406 return memory_xfer_auxv (ops, object, annex, readbuf, writebuf,
4407 offset, len, xfered_len);
4409 if (object == TARGET_OBJECT_OSDATA)
4410 return linux_nat_xfer_osdata (ops, object, annex, readbuf, writebuf,
4411 offset, len, xfered_len);
4413 if (object == TARGET_OBJECT_SPU)
4414 return linux_proc_xfer_spu (ops, object, annex, readbuf, writebuf,
4415 offset, len, xfered_len);
4417 /* GDB calculates all the addresses in possibly larget width of the address.
4418 Address width needs to be masked before its final use - either by
4419 linux_proc_xfer_partial or inf_ptrace_xfer_partial.
4421 Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
4423 if (object == TARGET_OBJECT_MEMORY)
4425 int addr_bit = gdbarch_addr_bit (target_gdbarch ());
4427 if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
4428 offset &= ((ULONGEST) 1 << addr_bit) - 1;
4431 xfer = linux_proc_xfer_partial (ops, object, annex, readbuf, writebuf,
4432 offset, len, xfered_len);
4433 if (xfer != TARGET_XFER_EOF)
4436 return super_xfer_partial (ops, object, annex, readbuf, writebuf,
4437 offset, len, xfered_len);
4441 cleanup_target_stop (void *arg)
4443 ptid_t *ptid = (ptid_t *) arg;
4445 gdb_assert (arg != NULL);
4448 target_resume (*ptid, 0, GDB_SIGNAL_0);
4451 static VEC(static_tracepoint_marker_p) *
4452 linux_child_static_tracepoint_markers_by_strid (struct target_ops *self,
4455 char s[IPA_CMD_BUF_SIZE];
4456 struct cleanup *old_chain;
4457 int pid = ptid_get_pid (inferior_ptid);
4458 VEC(static_tracepoint_marker_p) *markers = NULL;
4459 struct static_tracepoint_marker *marker = NULL;
4461 ptid_t ptid = ptid_build (pid, 0, 0);
4466 memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
4467 s[sizeof ("qTfSTM")] = 0;
4469 agent_run_command (pid, s, strlen (s) + 1);
4471 old_chain = make_cleanup (free_current_marker, &marker);
4472 make_cleanup (cleanup_target_stop, &ptid);
4477 marker = XCNEW (struct static_tracepoint_marker);
4481 parse_static_tracepoint_marker_definition (p, &p, marker);
4483 if (strid == NULL || strcmp (strid, marker->str_id) == 0)
4485 VEC_safe_push (static_tracepoint_marker_p,
4491 release_static_tracepoint_marker (marker);
4492 memset (marker, 0, sizeof (*marker));
4495 while (*p++ == ','); /* comma-separated list */
4497 memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
4498 s[sizeof ("qTsSTM")] = 0;
4499 agent_run_command (pid, s, strlen (s) + 1);
4503 do_cleanups (old_chain);
4508 /* Create a prototype generic GNU/Linux target. The client can override
4509 it with local methods. */
4512 linux_target_install_ops (struct target_ops *t)
4514 t->to_insert_fork_catchpoint = linux_child_insert_fork_catchpoint;
4515 t->to_remove_fork_catchpoint = linux_child_remove_fork_catchpoint;
4516 t->to_insert_vfork_catchpoint = linux_child_insert_vfork_catchpoint;
4517 t->to_remove_vfork_catchpoint = linux_child_remove_vfork_catchpoint;
4518 t->to_insert_exec_catchpoint = linux_child_insert_exec_catchpoint;
4519 t->to_remove_exec_catchpoint = linux_child_remove_exec_catchpoint;
4520 t->to_set_syscall_catchpoint = linux_child_set_syscall_catchpoint;
4521 t->to_pid_to_exec_file = linux_child_pid_to_exec_file;
4522 t->to_post_startup_inferior = linux_child_post_startup_inferior;
4523 t->to_post_attach = linux_child_post_attach;
4524 t->to_follow_fork = linux_child_follow_fork;
4525 t->to_make_corefile_notes = linux_nat_make_corefile_notes;
4527 super_xfer_partial = t->to_xfer_partial;
4528 t->to_xfer_partial = linux_xfer_partial;
4530 t->to_static_tracepoint_markers_by_strid
4531 = linux_child_static_tracepoint_markers_by_strid;
4537 struct target_ops *t;
4539 t = inf_ptrace_target ();
4540 linux_target_install_ops (t);
4546 linux_trad_target (CORE_ADDR (*register_u_offset)(struct gdbarch *, int, int))
4548 struct target_ops *t;
4550 t = inf_ptrace_trad_target (register_u_offset);
4551 linux_target_install_ops (t);
4556 /* target_is_async_p implementation. */
4559 linux_nat_is_async_p (struct target_ops *ops)
4561 /* NOTE: palves 2008-03-21: We're only async when the user requests
4562 it explicitly with the "set target-async" command.
4563 Someday, linux will always be async. */
4564 return target_async_permitted;
4567 /* target_can_async_p implementation. */
4570 linux_nat_can_async_p (struct target_ops *ops)
4572 /* NOTE: palves 2008-03-21: We're only async when the user requests
4573 it explicitly with the "set target-async" command.
4574 Someday, linux will always be async. */
4575 return target_async_permitted;
4579 linux_nat_supports_non_stop (struct target_ops *self)
4584 /* True if we want to support multi-process. To be removed when GDB
4585 supports multi-exec. */
4587 int linux_multi_process = 1;
4590 linux_nat_supports_multi_process (struct target_ops *self)
4592 return linux_multi_process;
4596 linux_nat_supports_disable_randomization (struct target_ops *self)
4598 #ifdef HAVE_PERSONALITY
4605 static int async_terminal_is_ours = 1;
4607 /* target_terminal_inferior implementation.
4609 This is a wrapper around child_terminal_inferior to add async support. */
4612 linux_nat_terminal_inferior (struct target_ops *self)
4614 if (!target_is_async_p ())
4616 /* Async mode is disabled. */
4617 child_terminal_inferior (self);
4621 child_terminal_inferior (self);
4623 /* Calls to target_terminal_*() are meant to be idempotent. */
4624 if (!async_terminal_is_ours)
4627 delete_file_handler (input_fd);
4628 async_terminal_is_ours = 0;
4632 /* target_terminal_ours implementation.
4634 This is a wrapper around child_terminal_ours to add async support (and
4635 implement the target_terminal_ours vs target_terminal_ours_for_output
4636 distinction). child_terminal_ours is currently no different than
4637 child_terminal_ours_for_output.
4638 We leave target_terminal_ours_for_output alone, leaving it to
4639 child_terminal_ours_for_output. */
4642 linux_nat_terminal_ours (struct target_ops *self)
4644 if (!target_is_async_p ())
4646 /* Async mode is disabled. */
4647 child_terminal_ours (self);
4651 /* GDB should never give the terminal to the inferior if the
4652 inferior is running in the background (run&, continue&, etc.),
4653 but claiming it sure should. */
4654 child_terminal_ours (self);
4656 if (async_terminal_is_ours)
4659 clear_sigint_trap ();
4660 add_file_handler (input_fd, stdin_event_handler, 0);
4661 async_terminal_is_ours = 1;
4664 static void (*async_client_callback) (enum inferior_event_type event_type,
4666 static void *async_client_context;
4668 /* SIGCHLD handler that serves two purposes: In non-stop/async mode,
4669 so we notice when any child changes state, and notify the
4670 event-loop; it allows us to use sigsuspend in linux_nat_wait_1
4671 above to wait for the arrival of a SIGCHLD. */
4674 sigchld_handler (int signo)
4676 int old_errno = errno;
4678 if (debug_linux_nat)
4679 ui_file_write_async_safe (gdb_stdlog,
4680 "sigchld\n", sizeof ("sigchld\n") - 1);
4682 if (signo == SIGCHLD
4683 && linux_nat_event_pipe[0] != -1)
4684 async_file_mark (); /* Let the event loop know that there are
4685 events to handle. */
4690 /* Callback registered with the target events file descriptor. */
4693 handle_target_event (int error, gdb_client_data client_data)
4695 (*async_client_callback) (INF_REG_EVENT, async_client_context);
4698 /* Create/destroy the target events pipe. Returns previous state. */
4701 linux_async_pipe (int enable)
4703 int previous = (linux_nat_event_pipe[0] != -1);
4705 if (previous != enable)
4709 /* Block child signals while we create/destroy the pipe, as
4710 their handler writes to it. */
4711 block_child_signals (&prev_mask);
4715 if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
4716 internal_error (__FILE__, __LINE__,
4717 "creating event pipe failed.");
4719 fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
4720 fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
4724 close (linux_nat_event_pipe[0]);
4725 close (linux_nat_event_pipe[1]);
4726 linux_nat_event_pipe[0] = -1;
4727 linux_nat_event_pipe[1] = -1;
4730 restore_child_signals_mask (&prev_mask);
4736 /* target_async implementation. */
4739 linux_nat_async (struct target_ops *ops,
4740 void (*callback) (enum inferior_event_type event_type,
4744 if (callback != NULL)
4746 async_client_callback = callback;
4747 async_client_context = context;
4748 if (!linux_async_pipe (1))
4750 add_file_handler (linux_nat_event_pipe[0],
4751 handle_target_event, NULL);
4752 /* There may be pending events to handle. Tell the event loop
4759 async_client_callback = callback;
4760 async_client_context = context;
4761 delete_file_handler (linux_nat_event_pipe[0]);
4762 linux_async_pipe (0);
4767 /* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
4771 linux_nat_stop_lwp (struct lwp_info *lwp, void *data)
4775 if (debug_linux_nat)
4776 fprintf_unfiltered (gdb_stdlog,
4777 "LNSL: running -> suspending %s\n",
4778 target_pid_to_str (lwp->ptid));
4781 if (lwp->last_resume_kind == resume_stop)
4783 if (debug_linux_nat)
4784 fprintf_unfiltered (gdb_stdlog,
4785 "linux-nat: already stopping LWP %ld at "
4787 ptid_get_lwp (lwp->ptid));
4791 stop_callback (lwp, NULL);
4792 lwp->last_resume_kind = resume_stop;
4796 /* Already known to be stopped; do nothing. */
4798 if (debug_linux_nat)
4800 if (find_thread_ptid (lwp->ptid)->stop_requested)
4801 fprintf_unfiltered (gdb_stdlog,
4802 "LNSL: already stopped/stop_requested %s\n",
4803 target_pid_to_str (lwp->ptid));
4805 fprintf_unfiltered (gdb_stdlog,
4806 "LNSL: already stopped/no "
4807 "stop_requested yet %s\n",
4808 target_pid_to_str (lwp->ptid));
4815 linux_nat_stop (struct target_ops *self, ptid_t ptid)
4818 iterate_over_lwps (ptid, linux_nat_stop_lwp, NULL);
4820 linux_ops->to_stop (linux_ops, ptid);
4824 linux_nat_close (struct target_ops *self)
4826 /* Unregister from the event loop. */
4827 if (linux_nat_is_async_p (self))
4828 linux_nat_async (self, NULL, NULL);
4830 if (linux_ops->to_close)
4831 linux_ops->to_close (linux_ops);
4836 /* When requests are passed down from the linux-nat layer to the
4837 single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
4838 used. The address space pointer is stored in the inferior object,
4839 but the common code that is passed such ptid can't tell whether
4840 lwpid is a "main" process id or not (it assumes so). We reverse
4841 look up the "main" process id from the lwp here. */
4843 static struct address_space *
4844 linux_nat_thread_address_space (struct target_ops *t, ptid_t ptid)
4846 struct lwp_info *lwp;
4847 struct inferior *inf;
4850 if (ptid_get_lwp (ptid) == 0)
4852 /* An (lwpid,0,0) ptid. Look up the lwp object to get at the
4854 lwp = find_lwp_pid (ptid);
4855 pid = ptid_get_pid (lwp->ptid);
4859 /* A (pid,lwpid,0) ptid. */
4860 pid = ptid_get_pid (ptid);
4863 inf = find_inferior_pid (pid);
4864 gdb_assert (inf != NULL);
4868 /* Return the cached value of the processor core for thread PTID. */
4871 linux_nat_core_of_thread (struct target_ops *ops, ptid_t ptid)
4873 struct lwp_info *info = find_lwp_pid (ptid);
4881 linux_nat_add_target (struct target_ops *t)
4883 /* Save the provided single-threaded target. We save this in a separate
4884 variable because another target we've inherited from (e.g. inf-ptrace)
4885 may have saved a pointer to T; we want to use it for the final
4886 process stratum target. */
4887 linux_ops_saved = *t;
4888 linux_ops = &linux_ops_saved;
4890 /* Override some methods for multithreading. */
4891 t->to_create_inferior = linux_nat_create_inferior;
4892 t->to_attach = linux_nat_attach;
4893 t->to_detach = linux_nat_detach;
4894 t->to_resume = linux_nat_resume;
4895 t->to_wait = linux_nat_wait;
4896 t->to_pass_signals = linux_nat_pass_signals;
4897 t->to_xfer_partial = linux_nat_xfer_partial;
4898 t->to_kill = linux_nat_kill;
4899 t->to_mourn_inferior = linux_nat_mourn_inferior;
4900 t->to_thread_alive = linux_nat_thread_alive;
4901 t->to_pid_to_str = linux_nat_pid_to_str;
4902 t->to_thread_name = linux_nat_thread_name;
4903 t->to_has_thread_control = tc_schedlock;
4904 t->to_thread_address_space = linux_nat_thread_address_space;
4905 t->to_stopped_by_watchpoint = linux_nat_stopped_by_watchpoint;
4906 t->to_stopped_data_address = linux_nat_stopped_data_address;
4908 t->to_can_async_p = linux_nat_can_async_p;
4909 t->to_is_async_p = linux_nat_is_async_p;
4910 t->to_supports_non_stop = linux_nat_supports_non_stop;
4911 t->to_async = linux_nat_async;
4912 t->to_terminal_inferior = linux_nat_terminal_inferior;
4913 t->to_terminal_ours = linux_nat_terminal_ours;
4915 super_close = t->to_close;
4916 t->to_close = linux_nat_close;
4918 /* Methods for non-stop support. */
4919 t->to_stop = linux_nat_stop;
4921 t->to_supports_multi_process = linux_nat_supports_multi_process;
4923 t->to_supports_disable_randomization
4924 = linux_nat_supports_disable_randomization;
4926 t->to_core_of_thread = linux_nat_core_of_thread;
4928 /* We don't change the stratum; this target will sit at
4929 process_stratum and thread_db will set at thread_stratum. This
4930 is a little strange, since this is a multi-threaded-capable
4931 target, but we want to be on the stack below thread_db, and we
4932 also want to be used for single-threaded processes. */
4937 /* Register a method to call whenever a new thread is attached. */
4939 linux_nat_set_new_thread (struct target_ops *t,
4940 void (*new_thread) (struct lwp_info *))
4942 /* Save the pointer. We only support a single registered instance
4943 of the GNU/Linux native target, so we do not need to map this to
4945 linux_nat_new_thread = new_thread;
4948 /* See declaration in linux-nat.h. */
4951 linux_nat_set_new_fork (struct target_ops *t,
4952 linux_nat_new_fork_ftype *new_fork)
4954 /* Save the pointer. */
4955 linux_nat_new_fork = new_fork;
4958 /* See declaration in linux-nat.h. */
4961 linux_nat_set_forget_process (struct target_ops *t,
4962 linux_nat_forget_process_ftype *fn)
4964 /* Save the pointer. */
4965 linux_nat_forget_process_hook = fn;
4968 /* See declaration in linux-nat.h. */
4971 linux_nat_forget_process (pid_t pid)
4973 if (linux_nat_forget_process_hook != NULL)
4974 linux_nat_forget_process_hook (pid);
4977 /* Register a method that converts a siginfo object between the layout
4978 that ptrace returns, and the layout in the architecture of the
4981 linux_nat_set_siginfo_fixup (struct target_ops *t,
4982 int (*siginfo_fixup) (siginfo_t *,
4986 /* Save the pointer. */
4987 linux_nat_siginfo_fixup = siginfo_fixup;
4990 /* Register a method to call prior to resuming a thread. */
4993 linux_nat_set_prepare_to_resume (struct target_ops *t,
4994 void (*prepare_to_resume) (struct lwp_info *))
4996 /* Save the pointer. */
4997 linux_nat_prepare_to_resume = prepare_to_resume;
5000 /* See linux-nat.h. */
5003 linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
5007 pid = ptid_get_lwp (ptid);
5009 pid = ptid_get_pid (ptid);
5012 ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
5015 memset (siginfo, 0, sizeof (*siginfo));
5021 /* Provide a prototype to silence -Wmissing-prototypes. */
5022 extern initialize_file_ftype _initialize_linux_nat;
5025 _initialize_linux_nat (void)
5027 add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
5028 &debug_linux_nat, _("\
5029 Set debugging of GNU/Linux lwp module."), _("\
5030 Show debugging of GNU/Linux lwp module."), _("\
5031 Enables printf debugging output."),
5033 show_debug_linux_nat,
5034 &setdebuglist, &showdebuglist);
5036 /* Save this mask as the default. */
5037 sigprocmask (SIG_SETMASK, NULL, &normal_mask);
5039 /* Install a SIGCHLD handler. */
5040 sigchld_action.sa_handler = sigchld_handler;
5041 sigemptyset (&sigchld_action.sa_mask);
5042 sigchld_action.sa_flags = SA_RESTART;
5044 /* Make it the default. */
5045 sigaction (SIGCHLD, &sigchld_action, NULL);
5047 /* Make sure we don't block SIGCHLD during a sigsuspend. */
5048 sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
5049 sigdelset (&suspend_mask, SIGCHLD);
5051 sigemptyset (&blocked_mask);
5053 /* Do not enable PTRACE_O_TRACEEXIT until GDB is more prepared to
5054 support read-only process state. */
5055 linux_ptrace_set_additional_flags (PTRACE_O_TRACESYSGOOD
5056 | PTRACE_O_TRACEVFORKDONE
5057 | PTRACE_O_TRACEVFORK
5058 | PTRACE_O_TRACEFORK
5059 | PTRACE_O_TRACEEXEC);
5063 /* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
5064 the GNU/Linux Threads library and therefore doesn't really belong
5067 /* Read variable NAME in the target and return its value if found.
5068 Otherwise return zero. It is assumed that the type of the variable
5072 get_signo (const char *name)
5074 struct bound_minimal_symbol ms;
5077 ms = lookup_minimal_symbol (name, NULL, NULL);
5078 if (ms.minsym == NULL)
5081 if (target_read_memory (BMSYMBOL_VALUE_ADDRESS (ms), (gdb_byte *) &signo,
5082 sizeof (signo)) != 0)
5088 /* Return the set of signals used by the threads library in *SET. */
5091 lin_thread_get_thread_signals (sigset_t *set)
5093 struct sigaction action;
5094 int restart, cancel;
5096 sigemptyset (&blocked_mask);
5099 restart = get_signo ("__pthread_sig_restart");
5100 cancel = get_signo ("__pthread_sig_cancel");
5102 /* LinuxThreads normally uses the first two RT signals, but in some legacy
5103 cases may use SIGUSR1/SIGUSR2. NPTL always uses RT signals, but does
5104 not provide any way for the debugger to query the signal numbers -
5105 fortunately they don't change! */
5108 restart = __SIGRTMIN;
5111 cancel = __SIGRTMIN + 1;
5113 sigaddset (set, restart);
5114 sigaddset (set, cancel);
5116 /* The GNU/Linux Threads library makes terminating threads send a
5117 special "cancel" signal instead of SIGCHLD. Make sure we catch
5118 those (to prevent them from terminating GDB itself, which is
5119 likely to be their default action) and treat them the same way as
5122 action.sa_handler = sigchld_handler;
5123 sigemptyset (&action.sa_mask);
5124 action.sa_flags = SA_RESTART;
5125 sigaction (cancel, &action, NULL);
5127 /* We block the "cancel" signal throughout this code ... */
5128 sigaddset (&blocked_mask, cancel);
5129 sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
5131 /* ... except during a sigsuspend. */
5132 sigdelset (&suspend_mask, cancel);