mirror of
https://sourceware.org/git/binutils-gdb.git
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21987b9c06
This adds configury support and an RAII class that can be used to temporarily block signals that are used by gdb. (This class is not used in this patch, but it split out for easier review.) The idea of this patch is that these signals should only be delivered to the main thread. So, when creating a background thread, they are temporarily blocked; the blocked state is inherited by the new thread. The sigprocmask man page says: The use of sigprocmask() is unspecified in a multithreaded process; see pthread_sigmask(3). This patch changes gdb to use pthread_sigmask when appropriate, by introducing a convenience define. I've updated gdbserver as well, because I had to touch gdbsupport, and because the threading patches will make it link against the thread library. I chose not to touch the NTO code, because I don't know anything about that platform and because I cannot test it. Finally, this modifies an existing spot in the Guile layer to use the new facility. gdb/ChangeLog 2019-11-26 Tom Tromey <tom@tromey.com> * gdbsupport/signals-state-save-restore.c (original_signal_mask): Remove comment. (save_original_signals_state, restore_original_signals_state): Use gdb_sigmask. * linux-nat.c (block_child_signals, restore_child_signals_mask) (_initialize_linux_nat): Use gdb_sigmask. * guile/guile.c (_initialize_guile): Use block_signals. * Makefile.in (HFILES_NO_SRCDIR): Add gdb-sigmask.h. * gdbsupport/gdb-sigmask.h: New file. * event-top.c (async_sigtstp_handler): Use gdb_sigmask. * cp-support.c (gdb_demangle): Use gdb_sigmask. * gdbsupport/common.m4 (GDB_AC_COMMON): Check for pthread_sigmask. * configure, config.in: Rebuild. * gdbsupport/block-signals.h: New file. gdb/gdbserver/ChangeLog 2019-11-26 Tom Tromey <tom@tromey.com> * remote-utils.c (block_unblock_async_io): Use gdb_sigmask. * linux-low.c (linux_wait_for_event_filtered, linux_async): Use gdb_sigmask. * configure, config.in: Rebuild. Change-Id: If3f37dc57dd859c226e9e4d79458a0514746e8c6
4594 lines
126 KiB
C
4594 lines
126 KiB
C
/* GNU/Linux native-dependent code common to multiple platforms.
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Copyright (C) 2001-2019 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "inferior.h"
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#include "infrun.h"
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#include "target.h"
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#include "nat/linux-nat.h"
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#include "nat/linux-waitpid.h"
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#include "gdbsupport/gdb_wait.h"
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#include <unistd.h>
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#include <sys/syscall.h>
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#include "nat/gdb_ptrace.h"
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#include "linux-nat.h"
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#include "nat/linux-ptrace.h"
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#include "nat/linux-procfs.h"
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#include "nat/linux-personality.h"
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#include "linux-fork.h"
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#include "gdbthread.h"
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#include "gdbcmd.h"
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#include "regcache.h"
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#include "regset.h"
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#include "inf-child.h"
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#include "inf-ptrace.h"
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#include "auxv.h"
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#include <sys/procfs.h> /* for elf_gregset etc. */
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#include "elf-bfd.h" /* for elfcore_write_* */
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#include "gregset.h" /* for gregset */
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#include "gdbcore.h" /* for get_exec_file */
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#include <ctype.h> /* for isdigit */
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#include <sys/stat.h> /* for struct stat */
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#include <fcntl.h> /* for O_RDONLY */
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#include "inf-loop.h"
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#include "event-loop.h"
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#include "event-top.h"
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#include <pwd.h>
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#include <sys/types.h>
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#include <dirent.h>
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#include "xml-support.h"
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#include <sys/vfs.h>
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#include "solib.h"
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#include "nat/linux-osdata.h"
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#include "linux-tdep.h"
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#include "symfile.h"
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#include "gdbsupport/agent.h"
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#include "tracepoint.h"
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#include "gdbsupport/buffer.h"
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#include "target-descriptions.h"
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#include "gdbsupport/filestuff.h"
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#include "objfiles.h"
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#include "nat/linux-namespaces.h"
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#include "gdbsupport/fileio.h"
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#include "gdbsupport/scope-exit.h"
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#include "gdbsupport/gdb-sigmask.h"
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/* This comment documents high-level logic of this file.
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Waiting for events in sync mode
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===============================
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When waiting for an event in a specific thread, we just use waitpid,
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passing the specific pid, and not passing WNOHANG.
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When waiting for an event in all threads, waitpid is not quite good:
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- If the thread group leader exits while other threads in the thread
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group still exist, waitpid(TGID, ...) hangs. That waitpid won't
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return an exit status until the other threads in the group are
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reaped.
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- When a non-leader thread execs, that thread just vanishes without
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reporting an exit (so we'd hang if we waited for it explicitly in
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that case). The exec event is instead reported to the TGID pid.
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The solution is to always use -1 and WNOHANG, together with
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sigsuspend.
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First, we use non-blocking waitpid to check for events. If nothing is
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found, we use sigsuspend to wait for SIGCHLD. When SIGCHLD arrives,
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it means something happened to a child process. As soon as we know
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there's an event, we get back to calling nonblocking waitpid.
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Note that SIGCHLD should be blocked between waitpid and sigsuspend
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calls, so that we don't miss a signal. If SIGCHLD arrives in between,
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when it's blocked, the signal becomes pending and sigsuspend
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immediately notices it and returns.
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Waiting for events in async mode (TARGET_WNOHANG)
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=================================================
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In async mode, GDB should always be ready to handle both user input
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and target events, so neither blocking waitpid nor sigsuspend are
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viable options. Instead, we should asynchronously notify the GDB main
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event loop whenever there's an unprocessed event from the target. We
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detect asynchronous target events by handling SIGCHLD signals. To
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notify the event loop about target events, the self-pipe trick is used
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--- a pipe is registered as waitable event source in the event loop,
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the event loop select/poll's on the read end of this pipe (as well on
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other event sources, e.g., stdin), and the SIGCHLD handler writes a
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byte to this pipe. This is more portable than relying on
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pselect/ppoll, since on kernels that lack those syscalls, libc
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emulates them with select/poll+sigprocmask, and that is racy
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(a.k.a. plain broken).
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Obviously, if we fail to notify the event loop if there's a target
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event, it's bad. OTOH, if we notify the event loop when there's no
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event from the target, linux_nat_wait will detect that there's no real
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event to report, and return event of type TARGET_WAITKIND_IGNORE.
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This is mostly harmless, but it will waste time and is better avoided.
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The main design point is that every time GDB is outside linux-nat.c,
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we have a SIGCHLD handler installed that is called when something
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happens to the target and notifies the GDB event loop. Whenever GDB
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core decides to handle the event, and calls into linux-nat.c, we
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process things as in sync mode, except that the we never block in
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sigsuspend.
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While processing an event, we may end up momentarily blocked in
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waitpid calls. Those waitpid calls, while blocking, are guarantied to
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return quickly. E.g., in all-stop mode, before reporting to the core
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that an LWP hit a breakpoint, all LWPs are stopped by sending them
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SIGSTOP, and synchronously waiting for the SIGSTOP to be reported.
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Note that this is different from blocking indefinitely waiting for the
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next event --- here, we're already handling an event.
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Use of signals
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==============
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We stop threads by sending a SIGSTOP. The use of SIGSTOP instead of another
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signal is not entirely significant; we just need for a signal to be delivered,
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so that we can intercept it. SIGSTOP's advantage is that it can not be
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blocked. A disadvantage is that it is not a real-time signal, so it can only
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be queued once; we do not keep track of other sources of SIGSTOP.
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Two other signals that can't be blocked are SIGCONT and SIGKILL. But we can't
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use them, because they have special behavior when the signal is generated -
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not when it is delivered. SIGCONT resumes the entire thread group and SIGKILL
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kills the entire thread group.
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A delivered SIGSTOP would stop the entire thread group, not just the thread we
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tkill'd. But we never let the SIGSTOP be delivered; we always intercept and
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cancel it (by PTRACE_CONT without passing SIGSTOP).
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We could use a real-time signal instead. This would solve those problems; we
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could use PTRACE_GETSIGINFO to locate the specific stop signals sent by GDB.
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But we would still have to have some support for SIGSTOP, since PTRACE_ATTACH
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generates it, and there are races with trying to find a signal that is not
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blocked.
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Exec events
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===========
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The case of a thread group (process) with 3 or more threads, and a
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thread other than the leader execs is worth detailing:
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On an exec, the Linux kernel destroys all threads except the execing
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one in the thread group, and resets the execing thread's tid to the
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tgid. No exit notification is sent for the execing thread -- from the
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ptracer's perspective, it appears as though the execing thread just
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vanishes. Until we reap all other threads except the leader and the
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execing thread, the leader will be zombie, and the execing thread will
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be in `D (disc sleep)' state. As soon as all other threads are
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reaped, the execing thread changes its tid to the tgid, and the
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previous (zombie) leader vanishes, giving place to the "new"
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leader. */
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#ifndef O_LARGEFILE
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#define O_LARGEFILE 0
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#endif
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struct linux_nat_target *linux_target;
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/* Does the current host support PTRACE_GETREGSET? */
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enum tribool have_ptrace_getregset = TRIBOOL_UNKNOWN;
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static unsigned int debug_linux_nat;
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static void
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show_debug_linux_nat (struct ui_file *file, int from_tty,
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struct cmd_list_element *c, const char *value)
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{
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fprintf_filtered (file, _("Debugging of GNU/Linux lwp module is %s.\n"),
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value);
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}
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struct simple_pid_list
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{
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int pid;
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int status;
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struct simple_pid_list *next;
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};
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struct simple_pid_list *stopped_pids;
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/* Whether target_thread_events is in effect. */
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static int report_thread_events;
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/* Async mode support. */
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/* The read/write ends of the pipe registered as waitable file in the
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event loop. */
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static int linux_nat_event_pipe[2] = { -1, -1 };
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/* True if we're currently in async mode. */
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#define linux_is_async_p() (linux_nat_event_pipe[0] != -1)
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/* Flush the event pipe. */
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static void
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async_file_flush (void)
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{
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int ret;
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char buf;
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do
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{
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ret = read (linux_nat_event_pipe[0], &buf, 1);
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}
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while (ret >= 0 || (ret == -1 && errno == EINTR));
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}
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/* Put something (anything, doesn't matter what, or how much) in event
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pipe, so that the select/poll in the event-loop realizes we have
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something to process. */
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static void
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async_file_mark (void)
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{
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int ret;
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/* It doesn't really matter what the pipe contains, as long we end
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up with something in it. Might as well flush the previous
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left-overs. */
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async_file_flush ();
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do
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{
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ret = write (linux_nat_event_pipe[1], "+", 1);
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}
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while (ret == -1 && errno == EINTR);
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/* Ignore EAGAIN. If the pipe is full, the event loop will already
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be awakened anyway. */
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}
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static int kill_lwp (int lwpid, int signo);
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static int stop_callback (struct lwp_info *lp);
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static void block_child_signals (sigset_t *prev_mask);
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static void restore_child_signals_mask (sigset_t *prev_mask);
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struct lwp_info;
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static struct lwp_info *add_lwp (ptid_t ptid);
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static void purge_lwp_list (int pid);
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static void delete_lwp (ptid_t ptid);
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static struct lwp_info *find_lwp_pid (ptid_t ptid);
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static int lwp_status_pending_p (struct lwp_info *lp);
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static void save_stop_reason (struct lwp_info *lp);
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/* LWP accessors. */
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/* See nat/linux-nat.h. */
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ptid_t
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ptid_of_lwp (struct lwp_info *lwp)
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{
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return lwp->ptid;
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}
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/* See nat/linux-nat.h. */
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void
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lwp_set_arch_private_info (struct lwp_info *lwp,
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struct arch_lwp_info *info)
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{
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lwp->arch_private = info;
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}
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/* See nat/linux-nat.h. */
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struct arch_lwp_info *
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lwp_arch_private_info (struct lwp_info *lwp)
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{
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return lwp->arch_private;
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}
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/* See nat/linux-nat.h. */
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int
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lwp_is_stopped (struct lwp_info *lwp)
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{
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return lwp->stopped;
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}
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/* See nat/linux-nat.h. */
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enum target_stop_reason
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lwp_stop_reason (struct lwp_info *lwp)
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{
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return lwp->stop_reason;
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}
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/* See nat/linux-nat.h. */
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int
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lwp_is_stepping (struct lwp_info *lwp)
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{
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return lwp->step;
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}
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/* Trivial list manipulation functions to keep track of a list of
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new stopped processes. */
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static void
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add_to_pid_list (struct simple_pid_list **listp, int pid, int status)
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{
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struct simple_pid_list *new_pid = XNEW (struct simple_pid_list);
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new_pid->pid = pid;
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new_pid->status = status;
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new_pid->next = *listp;
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*listp = new_pid;
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}
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static int
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pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp)
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{
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struct simple_pid_list **p;
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for (p = listp; *p != NULL; p = &(*p)->next)
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if ((*p)->pid == pid)
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{
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struct simple_pid_list *next = (*p)->next;
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*statusp = (*p)->status;
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xfree (*p);
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*p = next;
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return 1;
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}
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return 0;
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}
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/* Return the ptrace options that we want to try to enable. */
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static int
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linux_nat_ptrace_options (int attached)
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{
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int options = 0;
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if (!attached)
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options |= PTRACE_O_EXITKILL;
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options |= (PTRACE_O_TRACESYSGOOD
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| PTRACE_O_TRACEVFORKDONE
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| PTRACE_O_TRACEVFORK
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| PTRACE_O_TRACEFORK
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| PTRACE_O_TRACEEXEC);
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return options;
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}
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/* Initialize ptrace and procfs warnings and check for supported
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ptrace features given PID.
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ATTACHED should be nonzero iff we attached to the inferior. */
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static void
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linux_init_ptrace_procfs (pid_t pid, int attached)
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{
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int options = linux_nat_ptrace_options (attached);
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linux_enable_event_reporting (pid, options);
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linux_ptrace_init_warnings ();
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linux_proc_init_warnings ();
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}
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linux_nat_target::~linux_nat_target ()
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{}
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void
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linux_nat_target::post_attach (int pid)
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{
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linux_init_ptrace_procfs (pid, 1);
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}
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void
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linux_nat_target::post_startup_inferior (ptid_t ptid)
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{
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linux_init_ptrace_procfs (ptid.pid (), 0);
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}
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/* Return the number of known LWPs in the tgid given by PID. */
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static int
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num_lwps (int pid)
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{
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int count = 0;
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struct lwp_info *lp;
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for (lp = lwp_list; lp; lp = lp->next)
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if (lp->ptid.pid () == pid)
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count++;
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return count;
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}
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||
/* Deleter for lwp_info unique_ptr specialisation. */
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||
struct lwp_deleter
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||
{
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||
void operator() (struct lwp_info *lwp) const
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{
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delete_lwp (lwp->ptid);
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||
}
|
||
};
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||
|
||
/* A unique_ptr specialisation for lwp_info. */
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||
typedef std::unique_ptr<struct lwp_info, lwp_deleter> lwp_info_up;
|
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||
/* Target hook for follow_fork. On entry inferior_ptid must be the
|
||
ptid of the followed inferior. At return, inferior_ptid will be
|
||
unchanged. */
|
||
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||
int
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||
linux_nat_target::follow_fork (int follow_child, int detach_fork)
|
||
{
|
||
if (!follow_child)
|
||
{
|
||
struct lwp_info *child_lp = NULL;
|
||
int has_vforked;
|
||
ptid_t parent_ptid, child_ptid;
|
||
int parent_pid, child_pid;
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||
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||
has_vforked = (inferior_thread ()->pending_follow.kind
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||
== TARGET_WAITKIND_VFORKED);
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||
parent_ptid = inferior_ptid;
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||
child_ptid = inferior_thread ()->pending_follow.value.related_pid;
|
||
parent_pid = parent_ptid.lwp ();
|
||
child_pid = child_ptid.lwp ();
|
||
|
||
/* We're already attached to the parent, by default. */
|
||
child_lp = add_lwp (child_ptid);
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||
child_lp->stopped = 1;
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||
child_lp->last_resume_kind = resume_stop;
|
||
|
||
/* Detach new forked process? */
|
||
if (detach_fork)
|
||
{
|
||
int child_stop_signal = 0;
|
||
bool detach_child = true;
|
||
|
||
/* Move CHILD_LP into a unique_ptr and clear the source pointer
|
||
to prevent us doing anything stupid with it. */
|
||
lwp_info_up child_lp_ptr (child_lp);
|
||
child_lp = nullptr;
|
||
|
||
linux_target->low_prepare_to_resume (child_lp_ptr.get ());
|
||
|
||
/* When debugging an inferior in an architecture that supports
|
||
hardware single stepping on a kernel without commit
|
||
6580807da14c423f0d0a708108e6df6ebc8bc83d, the vfork child
|
||
process starts with the TIF_SINGLESTEP/X86_EFLAGS_TF bits
|
||
set if the parent process had them set.
|
||
To work around this, single step the child process
|
||
once before detaching to clear the flags. */
|
||
|
||
/* Note that we consult the parent's architecture instead of
|
||
the child's because there's no inferior for the child at
|
||
this point. */
|
||
if (!gdbarch_software_single_step_p (target_thread_architecture
|
||
(parent_ptid)))
|
||
{
|
||
int status;
|
||
|
||
linux_disable_event_reporting (child_pid);
|
||
if (ptrace (PTRACE_SINGLESTEP, child_pid, 0, 0) < 0)
|
||
perror_with_name (_("Couldn't do single step"));
|
||
if (my_waitpid (child_pid, &status, 0) < 0)
|
||
perror_with_name (_("Couldn't wait vfork process"));
|
||
else
|
||
{
|
||
detach_child = WIFSTOPPED (status);
|
||
child_stop_signal = WSTOPSIG (status);
|
||
}
|
||
}
|
||
|
||
if (detach_child)
|
||
{
|
||
int signo = child_stop_signal;
|
||
|
||
if (signo != 0
|
||
&& !signal_pass_state (gdb_signal_from_host (signo)))
|
||
signo = 0;
|
||
ptrace (PTRACE_DETACH, child_pid, 0, signo);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
scoped_restore save_inferior_ptid
|
||
= make_scoped_restore (&inferior_ptid);
|
||
inferior_ptid = child_ptid;
|
||
|
||
/* Let the thread_db layer learn about this new process. */
|
||
check_for_thread_db ();
|
||
}
|
||
|
||
if (has_vforked)
|
||
{
|
||
struct lwp_info *parent_lp;
|
||
|
||
parent_lp = find_lwp_pid (parent_ptid);
|
||
gdb_assert (linux_supports_tracefork () >= 0);
|
||
|
||
if (linux_supports_tracevforkdone ())
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LCFF: waiting for VFORK_DONE on %d\n",
|
||
parent_pid);
|
||
parent_lp->stopped = 1;
|
||
|
||
/* We'll handle the VFORK_DONE event like any other
|
||
event, in target_wait. */
|
||
}
|
||
else
|
||
{
|
||
/* We can't insert breakpoints until the child has
|
||
finished with the shared memory region. We need to
|
||
wait until that happens. Ideal would be to just
|
||
call:
|
||
- ptrace (PTRACE_SYSCALL, parent_pid, 0, 0);
|
||
- waitpid (parent_pid, &status, __WALL);
|
||
However, most architectures can't handle a syscall
|
||
being traced on the way out if it wasn't traced on
|
||
the way in.
|
||
|
||
We might also think to loop, continuing the child
|
||
until it exits or gets a SIGTRAP. One problem is
|
||
that the child might call ptrace with PTRACE_TRACEME.
|
||
|
||
There's no simple and reliable way to figure out when
|
||
the vforked child will be done with its copy of the
|
||
shared memory. We could step it out of the syscall,
|
||
two instructions, let it go, and then single-step the
|
||
parent once. When we have hardware single-step, this
|
||
would work; with software single-step it could still
|
||
be made to work but we'd have to be able to insert
|
||
single-step breakpoints in the child, and we'd have
|
||
to insert -just- the single-step breakpoint in the
|
||
parent. Very awkward.
|
||
|
||
In the end, the best we can do is to make sure it
|
||
runs for a little while. Hopefully it will be out of
|
||
range of any breakpoints we reinsert. Usually this
|
||
is only the single-step breakpoint at vfork's return
|
||
point. */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LCFF: no VFORK_DONE "
|
||
"support, sleeping a bit\n");
|
||
|
||
usleep (10000);
|
||
|
||
/* Pretend we've seen a PTRACE_EVENT_VFORK_DONE event,
|
||
and leave it pending. The next linux_nat_resume call
|
||
will notice a pending event, and bypasses actually
|
||
resuming the inferior. */
|
||
parent_lp->status = 0;
|
||
parent_lp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE;
|
||
parent_lp->stopped = 1;
|
||
|
||
/* If we're in async mode, need to tell the event loop
|
||
there's something here to process. */
|
||
if (target_is_async_p ())
|
||
async_file_mark ();
|
||
}
|
||
}
|
||
}
|
||
else
|
||
{
|
||
struct lwp_info *child_lp;
|
||
|
||
child_lp = add_lwp (inferior_ptid);
|
||
child_lp->stopped = 1;
|
||
child_lp->last_resume_kind = resume_stop;
|
||
|
||
/* Let the thread_db layer learn about this new process. */
|
||
check_for_thread_db ();
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
|
||
int
|
||
linux_nat_target::insert_fork_catchpoint (int pid)
|
||
{
|
||
return !linux_supports_tracefork ();
|
||
}
|
||
|
||
int
|
||
linux_nat_target::remove_fork_catchpoint (int pid)
|
||
{
|
||
return 0;
|
||
}
|
||
|
||
int
|
||
linux_nat_target::insert_vfork_catchpoint (int pid)
|
||
{
|
||
return !linux_supports_tracefork ();
|
||
}
|
||
|
||
int
|
||
linux_nat_target::remove_vfork_catchpoint (int pid)
|
||
{
|
||
return 0;
|
||
}
|
||
|
||
int
|
||
linux_nat_target::insert_exec_catchpoint (int pid)
|
||
{
|
||
return !linux_supports_tracefork ();
|
||
}
|
||
|
||
int
|
||
linux_nat_target::remove_exec_catchpoint (int pid)
|
||
{
|
||
return 0;
|
||
}
|
||
|
||
int
|
||
linux_nat_target::set_syscall_catchpoint (int pid, bool needed, int any_count,
|
||
gdb::array_view<const int> syscall_counts)
|
||
{
|
||
if (!linux_supports_tracesysgood ())
|
||
return 1;
|
||
|
||
/* On GNU/Linux, we ignore the arguments. It means that we only
|
||
enable the syscall catchpoints, but do not disable them.
|
||
|
||
Also, we do not use the `syscall_counts' information because we do not
|
||
filter system calls here. We let GDB do the logic for us. */
|
||
return 0;
|
||
}
|
||
|
||
/* List of known LWPs, keyed by LWP PID. This speeds up the common
|
||
case of mapping a PID returned from the kernel to our corresponding
|
||
lwp_info data structure. */
|
||
static htab_t lwp_lwpid_htab;
|
||
|
||
/* Calculate a hash from a lwp_info's LWP PID. */
|
||
|
||
static hashval_t
|
||
lwp_info_hash (const void *ap)
|
||
{
|
||
const struct lwp_info *lp = (struct lwp_info *) ap;
|
||
pid_t pid = lp->ptid.lwp ();
|
||
|
||
return iterative_hash_object (pid, 0);
|
||
}
|
||
|
||
/* Equality function for the lwp_info hash table. Compares the LWP's
|
||
PID. */
|
||
|
||
static int
|
||
lwp_lwpid_htab_eq (const void *a, const void *b)
|
||
{
|
||
const struct lwp_info *entry = (const struct lwp_info *) a;
|
||
const struct lwp_info *element = (const struct lwp_info *) b;
|
||
|
||
return entry->ptid.lwp () == element->ptid.lwp ();
|
||
}
|
||
|
||
/* Create the lwp_lwpid_htab hash table. */
|
||
|
||
static void
|
||
lwp_lwpid_htab_create (void)
|
||
{
|
||
lwp_lwpid_htab = htab_create (100, lwp_info_hash, lwp_lwpid_htab_eq, NULL);
|
||
}
|
||
|
||
/* Add LP to the hash table. */
|
||
|
||
static void
|
||
lwp_lwpid_htab_add_lwp (struct lwp_info *lp)
|
||
{
|
||
void **slot;
|
||
|
||
slot = htab_find_slot (lwp_lwpid_htab, lp, INSERT);
|
||
gdb_assert (slot != NULL && *slot == NULL);
|
||
*slot = lp;
|
||
}
|
||
|
||
/* Head of doubly-linked list of known LWPs. Sorted by reverse
|
||
creation order. This order is assumed in some cases. E.g.,
|
||
reaping status after killing alls lwps of a process: the leader LWP
|
||
must be reaped last. */
|
||
struct lwp_info *lwp_list;
|
||
|
||
/* Add LP to sorted-by-reverse-creation-order doubly-linked list. */
|
||
|
||
static void
|
||
lwp_list_add (struct lwp_info *lp)
|
||
{
|
||
lp->next = lwp_list;
|
||
if (lwp_list != NULL)
|
||
lwp_list->prev = lp;
|
||
lwp_list = lp;
|
||
}
|
||
|
||
/* Remove LP from sorted-by-reverse-creation-order doubly-linked
|
||
list. */
|
||
|
||
static void
|
||
lwp_list_remove (struct lwp_info *lp)
|
||
{
|
||
/* Remove from sorted-by-creation-order list. */
|
||
if (lp->next != NULL)
|
||
lp->next->prev = lp->prev;
|
||
if (lp->prev != NULL)
|
||
lp->prev->next = lp->next;
|
||
if (lp == lwp_list)
|
||
lwp_list = lp->next;
|
||
}
|
||
|
||
|
||
|
||
/* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
|
||
_initialize_linux_nat. */
|
||
static sigset_t suspend_mask;
|
||
|
||
/* Signals to block to make that sigsuspend work. */
|
||
static sigset_t blocked_mask;
|
||
|
||
/* SIGCHLD action. */
|
||
struct sigaction sigchld_action;
|
||
|
||
/* Block child signals (SIGCHLD and linux threads signals), and store
|
||
the previous mask in PREV_MASK. */
|
||
|
||
static void
|
||
block_child_signals (sigset_t *prev_mask)
|
||
{
|
||
/* Make sure SIGCHLD is blocked. */
|
||
if (!sigismember (&blocked_mask, SIGCHLD))
|
||
sigaddset (&blocked_mask, SIGCHLD);
|
||
|
||
gdb_sigmask (SIG_BLOCK, &blocked_mask, prev_mask);
|
||
}
|
||
|
||
/* Restore child signals mask, previously returned by
|
||
block_child_signals. */
|
||
|
||
static void
|
||
restore_child_signals_mask (sigset_t *prev_mask)
|
||
{
|
||
gdb_sigmask (SIG_SETMASK, prev_mask, NULL);
|
||
}
|
||
|
||
/* Mask of signals to pass directly to the inferior. */
|
||
static sigset_t pass_mask;
|
||
|
||
/* Update signals to pass to the inferior. */
|
||
void
|
||
linux_nat_target::pass_signals
|
||
(gdb::array_view<const unsigned char> pass_signals)
|
||
{
|
||
int signo;
|
||
|
||
sigemptyset (&pass_mask);
|
||
|
||
for (signo = 1; signo < NSIG; signo++)
|
||
{
|
||
int target_signo = gdb_signal_from_host (signo);
|
||
if (target_signo < pass_signals.size () && pass_signals[target_signo])
|
||
sigaddset (&pass_mask, signo);
|
||
}
|
||
}
|
||
|
||
|
||
|
||
/* Prototypes for local functions. */
|
||
static int stop_wait_callback (struct lwp_info *lp);
|
||
static int resume_stopped_resumed_lwps (struct lwp_info *lp, const ptid_t wait_ptid);
|
||
static int check_ptrace_stopped_lwp_gone (struct lwp_info *lp);
|
||
|
||
|
||
|
||
/* Destroy and free LP. */
|
||
|
||
static void
|
||
lwp_free (struct lwp_info *lp)
|
||
{
|
||
/* Let the arch specific bits release arch_lwp_info. */
|
||
linux_target->low_delete_thread (lp->arch_private);
|
||
|
||
xfree (lp);
|
||
}
|
||
|
||
/* Traversal function for purge_lwp_list. */
|
||
|
||
static int
|
||
lwp_lwpid_htab_remove_pid (void **slot, void *info)
|
||
{
|
||
struct lwp_info *lp = (struct lwp_info *) *slot;
|
||
int pid = *(int *) info;
|
||
|
||
if (lp->ptid.pid () == pid)
|
||
{
|
||
htab_clear_slot (lwp_lwpid_htab, slot);
|
||
lwp_list_remove (lp);
|
||
lwp_free (lp);
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Remove all LWPs belong to PID from the lwp list. */
|
||
|
||
static void
|
||
purge_lwp_list (int pid)
|
||
{
|
||
htab_traverse_noresize (lwp_lwpid_htab, lwp_lwpid_htab_remove_pid, &pid);
|
||
}
|
||
|
||
/* Add the LWP specified by PTID to the list. PTID is the first LWP
|
||
in the process. Return a pointer to the structure describing the
|
||
new LWP.
|
||
|
||
This differs from add_lwp in that we don't let the arch specific
|
||
bits know about this new thread. Current clients of this callback
|
||
take the opportunity to install watchpoints in the new thread, and
|
||
we shouldn't do that for the first thread. If we're spawning a
|
||
child ("run"), the thread executes the shell wrapper first, and we
|
||
shouldn't touch it until it execs the program we want to debug.
|
||
For "attach", it'd be okay to call the callback, but it's not
|
||
necessary, because watchpoints can't yet have been inserted into
|
||
the inferior. */
|
||
|
||
static struct lwp_info *
|
||
add_initial_lwp (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
|
||
gdb_assert (ptid.lwp_p ());
|
||
|
||
lp = XNEW (struct lwp_info);
|
||
|
||
memset (lp, 0, sizeof (struct lwp_info));
|
||
|
||
lp->last_resume_kind = resume_continue;
|
||
lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
|
||
|
||
lp->ptid = ptid;
|
||
lp->core = -1;
|
||
|
||
/* Add to sorted-by-reverse-creation-order list. */
|
||
lwp_list_add (lp);
|
||
|
||
/* Add to keyed-by-pid htab. */
|
||
lwp_lwpid_htab_add_lwp (lp);
|
||
|
||
return lp;
|
||
}
|
||
|
||
/* Add the LWP specified by PID to the list. Return a pointer to the
|
||
structure describing the new LWP. The LWP should already be
|
||
stopped. */
|
||
|
||
static struct lwp_info *
|
||
add_lwp (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
|
||
lp = add_initial_lwp (ptid);
|
||
|
||
/* Let the arch specific bits know about this new thread. Current
|
||
clients of this callback take the opportunity to install
|
||
watchpoints in the new thread. We don't do this for the first
|
||
thread though. See add_initial_lwp. */
|
||
linux_target->low_new_thread (lp);
|
||
|
||
return lp;
|
||
}
|
||
|
||
/* Remove the LWP specified by PID from the list. */
|
||
|
||
static void
|
||
delete_lwp (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
void **slot;
|
||
struct lwp_info dummy;
|
||
|
||
dummy.ptid = ptid;
|
||
slot = htab_find_slot (lwp_lwpid_htab, &dummy, NO_INSERT);
|
||
if (slot == NULL)
|
||
return;
|
||
|
||
lp = *(struct lwp_info **) slot;
|
||
gdb_assert (lp != NULL);
|
||
|
||
htab_clear_slot (lwp_lwpid_htab, slot);
|
||
|
||
/* Remove from sorted-by-creation-order list. */
|
||
lwp_list_remove (lp);
|
||
|
||
/* Release. */
|
||
lwp_free (lp);
|
||
}
|
||
|
||
/* Return a pointer to the structure describing the LWP corresponding
|
||
to PID. If no corresponding LWP could be found, return NULL. */
|
||
|
||
static struct lwp_info *
|
||
find_lwp_pid (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
int lwp;
|
||
struct lwp_info dummy;
|
||
|
||
if (ptid.lwp_p ())
|
||
lwp = ptid.lwp ();
|
||
else
|
||
lwp = ptid.pid ();
|
||
|
||
dummy.ptid = ptid_t (0, lwp, 0);
|
||
lp = (struct lwp_info *) htab_find (lwp_lwpid_htab, &dummy);
|
||
return lp;
|
||
}
|
||
|
||
/* See nat/linux-nat.h. */
|
||
|
||
struct lwp_info *
|
||
iterate_over_lwps (ptid_t filter,
|
||
gdb::function_view<iterate_over_lwps_ftype> callback)
|
||
{
|
||
struct lwp_info *lp, *lpnext;
|
||
|
||
for (lp = lwp_list; lp; lp = lpnext)
|
||
{
|
||
lpnext = lp->next;
|
||
|
||
if (lp->ptid.matches (filter))
|
||
{
|
||
if (callback (lp) != 0)
|
||
return lp;
|
||
}
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
/* Update our internal state when changing from one checkpoint to
|
||
another indicated by NEW_PTID. We can only switch single-threaded
|
||
applications, so we only create one new LWP, and the previous list
|
||
is discarded. */
|
||
|
||
void
|
||
linux_nat_switch_fork (ptid_t new_ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
|
||
purge_lwp_list (inferior_ptid.pid ());
|
||
|
||
lp = add_lwp (new_ptid);
|
||
lp->stopped = 1;
|
||
|
||
/* This changes the thread's ptid while preserving the gdb thread
|
||
num. Also changes the inferior pid, while preserving the
|
||
inferior num. */
|
||
thread_change_ptid (inferior_ptid, new_ptid);
|
||
|
||
/* We've just told GDB core that the thread changed target id, but,
|
||
in fact, it really is a different thread, with different register
|
||
contents. */
|
||
registers_changed ();
|
||
}
|
||
|
||
/* Handle the exit of a single thread LP. */
|
||
|
||
static void
|
||
exit_lwp (struct lwp_info *lp)
|
||
{
|
||
struct thread_info *th = find_thread_ptid (lp->ptid);
|
||
|
||
if (th)
|
||
{
|
||
if (print_thread_events)
|
||
printf_unfiltered (_("[%s exited]\n"),
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
|
||
delete_thread (th);
|
||
}
|
||
|
||
delete_lwp (lp->ptid);
|
||
}
|
||
|
||
/* Wait for the LWP specified by LP, which we have just attached to.
|
||
Returns a wait status for that LWP, to cache. */
|
||
|
||
static int
|
||
linux_nat_post_attach_wait (ptid_t ptid, int *signalled)
|
||
{
|
||
pid_t new_pid, pid = ptid.lwp ();
|
||
int status;
|
||
|
||
if (linux_proc_pid_is_stopped (pid))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNPAW: Attaching to a stopped process\n");
|
||
|
||
/* The process is definitely stopped. It is in a job control
|
||
stop, unless the kernel predates the TASK_STOPPED /
|
||
TASK_TRACED distinction, in which case it might be in a
|
||
ptrace stop. Make sure it is in a ptrace stop; from there we
|
||
can kill it, signal it, et cetera.
|
||
|
||
First make sure there is a pending SIGSTOP. Since we are
|
||
already attached, the process can not transition from stopped
|
||
to running without a PTRACE_CONT; so we know this signal will
|
||
go into the queue. The SIGSTOP generated by PTRACE_ATTACH is
|
||
probably already in the queue (unless this kernel is old
|
||
enough to use TASK_STOPPED for ptrace stops); but since SIGSTOP
|
||
is not an RT signal, it can only be queued once. */
|
||
kill_lwp (pid, SIGSTOP);
|
||
|
||
/* Finally, resume the stopped process. This will deliver the SIGSTOP
|
||
(or a higher priority signal, just like normal PTRACE_ATTACH). */
|
||
ptrace (PTRACE_CONT, pid, 0, 0);
|
||
}
|
||
|
||
/* Make sure the initial process is stopped. The user-level threads
|
||
layer might want to poke around in the inferior, and that won't
|
||
work if things haven't stabilized yet. */
|
||
new_pid = my_waitpid (pid, &status, __WALL);
|
||
gdb_assert (pid == new_pid);
|
||
|
||
if (!WIFSTOPPED (status))
|
||
{
|
||
/* The pid we tried to attach has apparently just exited. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "LNPAW: Failed to stop %d: %s",
|
||
pid, status_to_str (status));
|
||
return status;
|
||
}
|
||
|
||
if (WSTOPSIG (status) != SIGSTOP)
|
||
{
|
||
*signalled = 1;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNPAW: Received %s after attaching\n",
|
||
status_to_str (status));
|
||
}
|
||
|
||
return status;
|
||
}
|
||
|
||
void
|
||
linux_nat_target::create_inferior (const char *exec_file,
|
||
const std::string &allargs,
|
||
char **env, int from_tty)
|
||
{
|
||
maybe_disable_address_space_randomization restore_personality
|
||
(disable_randomization);
|
||
|
||
/* The fork_child mechanism is synchronous and calls target_wait, so
|
||
we have to mask the async mode. */
|
||
|
||
/* Make sure we report all signals during startup. */
|
||
pass_signals ({});
|
||
|
||
inf_ptrace_target::create_inferior (exec_file, allargs, env, from_tty);
|
||
}
|
||
|
||
/* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not
|
||
already attached. Returns true if a new LWP is found, false
|
||
otherwise. */
|
||
|
||
static int
|
||
attach_proc_task_lwp_callback (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lp;
|
||
|
||
/* Ignore LWPs we're already attached to. */
|
||
lp = find_lwp_pid (ptid);
|
||
if (lp == NULL)
|
||
{
|
||
int lwpid = ptid.lwp ();
|
||
|
||
if (ptrace (PTRACE_ATTACH, lwpid, 0, 0) < 0)
|
||
{
|
||
int err = errno;
|
||
|
||
/* Be quiet if we simply raced with the thread exiting.
|
||
EPERM is returned if the thread's task still exists, and
|
||
is marked as exited or zombie, as well as other
|
||
conditions, so in that case, confirm the status in
|
||
/proc/PID/status. */
|
||
if (err == ESRCH
|
||
|| (err == EPERM && linux_proc_pid_is_gone (lwpid)))
|
||
{
|
||
if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"Cannot attach to lwp %d: "
|
||
"thread is gone (%d: %s)\n",
|
||
lwpid, err, safe_strerror (err));
|
||
}
|
||
}
|
||
else
|
||
{
|
||
std::string reason
|
||
= linux_ptrace_attach_fail_reason_string (ptid, err);
|
||
|
||
warning (_("Cannot attach to lwp %d: %s"),
|
||
lwpid, reason.c_str ());
|
||
}
|
||
}
|
||
else
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"PTRACE_ATTACH %s, 0, 0 (OK)\n",
|
||
target_pid_to_str (ptid).c_str ());
|
||
|
||
lp = add_lwp (ptid);
|
||
|
||
/* The next time we wait for this LWP we'll see a SIGSTOP as
|
||
PTRACE_ATTACH brings it to a halt. */
|
||
lp->signalled = 1;
|
||
|
||
/* We need to wait for a stop before being able to make the
|
||
next ptrace call on this LWP. */
|
||
lp->must_set_ptrace_flags = 1;
|
||
|
||
/* So that wait collects the SIGSTOP. */
|
||
lp->resumed = 1;
|
||
|
||
/* Also add the LWP to gdb's thread list, in case a
|
||
matching libthread_db is not found (or the process uses
|
||
raw clone). */
|
||
add_thread (lp->ptid);
|
||
set_running (lp->ptid, 1);
|
||
set_executing (lp->ptid, 1);
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
void
|
||
linux_nat_target::attach (const char *args, int from_tty)
|
||
{
|
||
struct lwp_info *lp;
|
||
int status;
|
||
ptid_t ptid;
|
||
|
||
/* Make sure we report all signals during attach. */
|
||
pass_signals ({});
|
||
|
||
try
|
||
{
|
||
inf_ptrace_target::attach (args, from_tty);
|
||
}
|
||
catch (const gdb_exception_error &ex)
|
||
{
|
||
pid_t pid = parse_pid_to_attach (args);
|
||
std::string reason = linux_ptrace_attach_fail_reason (pid);
|
||
|
||
if (!reason.empty ())
|
||
throw_error (ex.error, "warning: %s\n%s", reason.c_str (),
|
||
ex.what ());
|
||
else
|
||
throw_error (ex.error, "%s", ex.what ());
|
||
}
|
||
|
||
/* The ptrace base target adds the main thread with (pid,0,0)
|
||
format. Decorate it with lwp info. */
|
||
ptid = ptid_t (inferior_ptid.pid (),
|
||
inferior_ptid.pid (),
|
||
0);
|
||
thread_change_ptid (inferior_ptid, ptid);
|
||
|
||
/* Add the initial process as the first LWP to the list. */
|
||
lp = add_initial_lwp (ptid);
|
||
|
||
status = linux_nat_post_attach_wait (lp->ptid, &lp->signalled);
|
||
if (!WIFSTOPPED (status))
|
||
{
|
||
if (WIFEXITED (status))
|
||
{
|
||
int exit_code = WEXITSTATUS (status);
|
||
|
||
target_terminal::ours ();
|
||
target_mourn_inferior (inferior_ptid);
|
||
if (exit_code == 0)
|
||
error (_("Unable to attach: program exited normally."));
|
||
else
|
||
error (_("Unable to attach: program exited with code %d."),
|
||
exit_code);
|
||
}
|
||
else if (WIFSIGNALED (status))
|
||
{
|
||
enum gdb_signal signo;
|
||
|
||
target_terminal::ours ();
|
||
target_mourn_inferior (inferior_ptid);
|
||
|
||
signo = gdb_signal_from_host (WTERMSIG (status));
|
||
error (_("Unable to attach: program terminated with signal "
|
||
"%s, %s."),
|
||
gdb_signal_to_name (signo),
|
||
gdb_signal_to_string (signo));
|
||
}
|
||
|
||
internal_error (__FILE__, __LINE__,
|
||
_("unexpected status %d for PID %ld"),
|
||
status, (long) ptid.lwp ());
|
||
}
|
||
|
||
lp->stopped = 1;
|
||
|
||
/* Save the wait status to report later. */
|
||
lp->resumed = 1;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNA: waitpid %ld, saving status %s\n",
|
||
(long) lp->ptid.pid (), status_to_str (status));
|
||
|
||
lp->status = status;
|
||
|
||
/* We must attach to every LWP. If /proc is mounted, use that to
|
||
find them now. The inferior may be using raw clone instead of
|
||
using pthreads. But even if it is using pthreads, thread_db
|
||
walks structures in the inferior's address space to find the list
|
||
of threads/LWPs, and those structures may well be corrupted.
|
||
Note that once thread_db is loaded, we'll still use it to list
|
||
threads and associate pthread info with each LWP. */
|
||
linux_proc_attach_tgid_threads (lp->ptid.pid (),
|
||
attach_proc_task_lwp_callback);
|
||
|
||
if (target_can_async_p ())
|
||
target_async (1);
|
||
}
|
||
|
||
/* Get pending signal of THREAD as a host signal number, for detaching
|
||
purposes. This is the signal the thread last stopped for, which we
|
||
need to deliver to the thread when detaching, otherwise, it'd be
|
||
suppressed/lost. */
|
||
|
||
static int
|
||
get_detach_signal (struct lwp_info *lp)
|
||
{
|
||
enum gdb_signal signo = GDB_SIGNAL_0;
|
||
|
||
/* If we paused threads momentarily, we may have stored pending
|
||
events in lp->status or lp->waitstatus (see stop_wait_callback),
|
||
and GDB core hasn't seen any signal for those threads.
|
||
Otherwise, the last signal reported to the core is found in the
|
||
thread object's stop_signal.
|
||
|
||
There's a corner case that isn't handled here at present. Only
|
||
if the thread stopped with a TARGET_WAITKIND_STOPPED does
|
||
stop_signal make sense as a real signal to pass to the inferior.
|
||
Some catchpoint related events, like
|
||
TARGET_WAITKIND_(V)FORK|EXEC|SYSCALL, have their stop_signal set
|
||
to GDB_SIGNAL_SIGTRAP when the catchpoint triggers. But,
|
||
those traps are debug API (ptrace in our case) related and
|
||
induced; the inferior wouldn't see them if it wasn't being
|
||
traced. Hence, we should never pass them to the inferior, even
|
||
when set to pass state. Since this corner case isn't handled by
|
||
infrun.c when proceeding with a signal, for consistency, neither
|
||
do we handle it here (or elsewhere in the file we check for
|
||
signal pass state). Normally SIGTRAP isn't set to pass state, so
|
||
this is really a corner case. */
|
||
|
||
if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
|
||
signo = GDB_SIGNAL_0; /* a pending ptrace event, not a real signal. */
|
||
else if (lp->status)
|
||
signo = gdb_signal_from_host (WSTOPSIG (lp->status));
|
||
else
|
||
{
|
||
struct thread_info *tp = find_thread_ptid (lp->ptid);
|
||
|
||
if (target_is_non_stop_p () && !tp->executing)
|
||
{
|
||
if (tp->suspend.waitstatus_pending_p)
|
||
signo = tp->suspend.waitstatus.value.sig;
|
||
else
|
||
signo = tp->suspend.stop_signal;
|
||
}
|
||
else if (!target_is_non_stop_p ())
|
||
{
|
||
struct target_waitstatus last;
|
||
ptid_t last_ptid;
|
||
|
||
get_last_target_status (&last_ptid, &last);
|
||
|
||
if (lp->ptid.lwp () == last_ptid.lwp ())
|
||
signo = tp->suspend.stop_signal;
|
||
}
|
||
}
|
||
|
||
if (signo == GDB_SIGNAL_0)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"GPT: lwp %s has no pending signal\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
else if (!signal_pass_state (signo))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"GPT: lwp %s had signal %s, "
|
||
"but it is in no pass state\n",
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
gdb_signal_to_string (signo));
|
||
}
|
||
else
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"GPT: lwp %s has pending signal %s\n",
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
gdb_signal_to_string (signo));
|
||
|
||
return gdb_signal_to_host (signo);
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Detach from LP. If SIGNO_P is non-NULL, then it points to the
|
||
signal number that should be passed to the LWP when detaching.
|
||
Otherwise pass any pending signal the LWP may have, if any. */
|
||
|
||
static void
|
||
detach_one_lwp (struct lwp_info *lp, int *signo_p)
|
||
{
|
||
int lwpid = lp->ptid.lwp ();
|
||
int signo;
|
||
|
||
gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
|
||
|
||
if (debug_linux_nat && lp->status)
|
||
fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
|
||
strsignal (WSTOPSIG (lp->status)),
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
|
||
/* If there is a pending SIGSTOP, get rid of it. */
|
||
if (lp->signalled)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"DC: Sending SIGCONT to %s\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
|
||
kill_lwp (lwpid, SIGCONT);
|
||
lp->signalled = 0;
|
||
}
|
||
|
||
if (signo_p == NULL)
|
||
{
|
||
/* Pass on any pending signal for this LWP. */
|
||
signo = get_detach_signal (lp);
|
||
}
|
||
else
|
||
signo = *signo_p;
|
||
|
||
/* Preparing to resume may try to write registers, and fail if the
|
||
lwp is zombie. If that happens, ignore the error. We'll handle
|
||
it below, when detach fails with ESRCH. */
|
||
try
|
||
{
|
||
linux_target->low_prepare_to_resume (lp);
|
||
}
|
||
catch (const gdb_exception_error &ex)
|
||
{
|
||
if (!check_ptrace_stopped_lwp_gone (lp))
|
||
throw;
|
||
}
|
||
|
||
if (ptrace (PTRACE_DETACH, lwpid, 0, signo) < 0)
|
||
{
|
||
int save_errno = errno;
|
||
|
||
/* We know the thread exists, so ESRCH must mean the lwp is
|
||
zombie. This can happen if one of the already-detached
|
||
threads exits the whole thread group. In that case we're
|
||
still attached, and must reap the lwp. */
|
||
if (save_errno == ESRCH)
|
||
{
|
||
int ret, status;
|
||
|
||
ret = my_waitpid (lwpid, &status, __WALL);
|
||
if (ret == -1)
|
||
{
|
||
warning (_("Couldn't reap LWP %d while detaching: %s"),
|
||
lwpid, safe_strerror (errno));
|
||
}
|
||
else if (!WIFEXITED (status) && !WIFSIGNALED (status))
|
||
{
|
||
warning (_("Reaping LWP %d while detaching "
|
||
"returned unexpected status 0x%x"),
|
||
lwpid, status);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
error (_("Can't detach %s: %s"),
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
safe_strerror (save_errno));
|
||
}
|
||
}
|
||
else if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"PTRACE_DETACH (%s, %s, 0) (OK)\n",
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
strsignal (signo));
|
||
}
|
||
|
||
delete_lwp (lp->ptid);
|
||
}
|
||
|
||
static int
|
||
detach_callback (struct lwp_info *lp)
|
||
{
|
||
/* We don't actually detach from the thread group leader just yet.
|
||
If the thread group exits, we must reap the zombie clone lwps
|
||
before we're able to reap the leader. */
|
||
if (lp->ptid.lwp () != lp->ptid.pid ())
|
||
detach_one_lwp (lp, NULL);
|
||
return 0;
|
||
}
|
||
|
||
void
|
||
linux_nat_target::detach (inferior *inf, int from_tty)
|
||
{
|
||
struct lwp_info *main_lwp;
|
||
int pid = inf->pid;
|
||
|
||
/* Don't unregister from the event loop, as there may be other
|
||
inferiors running. */
|
||
|
||
/* Stop all threads before detaching. ptrace requires that the
|
||
thread is stopped to successfully detach. */
|
||
iterate_over_lwps (ptid_t (pid), stop_callback);
|
||
/* ... and wait until all of them have reported back that
|
||
they're no longer running. */
|
||
iterate_over_lwps (ptid_t (pid), stop_wait_callback);
|
||
|
||
iterate_over_lwps (ptid_t (pid), detach_callback);
|
||
|
||
/* Only the initial process should be left right now. */
|
||
gdb_assert (num_lwps (pid) == 1);
|
||
|
||
main_lwp = find_lwp_pid (ptid_t (pid));
|
||
|
||
if (forks_exist_p ())
|
||
{
|
||
/* Multi-fork case. The current inferior_ptid is being detached
|
||
from, but there are other viable forks to debug. Detach from
|
||
the current fork, and context-switch to the first
|
||
available. */
|
||
linux_fork_detach (from_tty);
|
||
}
|
||
else
|
||
{
|
||
target_announce_detach (from_tty);
|
||
|
||
/* Pass on any pending signal for the last LWP. */
|
||
int signo = get_detach_signal (main_lwp);
|
||
|
||
detach_one_lwp (main_lwp, &signo);
|
||
|
||
detach_success (inf);
|
||
}
|
||
}
|
||
|
||
/* Resume execution of the inferior process. If STEP is nonzero,
|
||
single-step it. If SIGNAL is nonzero, give it that signal. */
|
||
|
||
static void
|
||
linux_resume_one_lwp_throw (struct lwp_info *lp, int step,
|
||
enum gdb_signal signo)
|
||
{
|
||
lp->step = step;
|
||
|
||
/* stop_pc doubles as the PC the LWP had when it was last resumed.
|
||
We only presently need that if the LWP is stepped though (to
|
||
handle the case of stepping a breakpoint instruction). */
|
||
if (step)
|
||
{
|
||
struct regcache *regcache = get_thread_regcache (lp->ptid);
|
||
|
||
lp->stop_pc = regcache_read_pc (regcache);
|
||
}
|
||
else
|
||
lp->stop_pc = 0;
|
||
|
||
linux_target->low_prepare_to_resume (lp);
|
||
linux_target->low_resume (lp->ptid, step, signo);
|
||
|
||
/* Successfully resumed. Clear state that no longer makes sense,
|
||
and mark the LWP as running. Must not do this before resuming
|
||
otherwise if that fails other code will be confused. E.g., we'd
|
||
later try to stop the LWP and hang forever waiting for a stop
|
||
status. Note that we must not throw after this is cleared,
|
||
otherwise handle_zombie_lwp_error would get confused. */
|
||
lp->stopped = 0;
|
||
lp->core = -1;
|
||
lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
|
||
registers_changed_ptid (lp->ptid);
|
||
}
|
||
|
||
/* Called when we try to resume a stopped LWP and that errors out. If
|
||
the LWP is no longer in ptrace-stopped state (meaning it's zombie,
|
||
or about to become), discard the error, clear any pending status
|
||
the LWP may have, and return true (we'll collect the exit status
|
||
soon enough). Otherwise, return false. */
|
||
|
||
static int
|
||
check_ptrace_stopped_lwp_gone (struct lwp_info *lp)
|
||
{
|
||
/* If we get an error after resuming the LWP successfully, we'd
|
||
confuse !T state for the LWP being gone. */
|
||
gdb_assert (lp->stopped);
|
||
|
||
/* We can't just check whether the LWP is in 'Z (Zombie)' state,
|
||
because even if ptrace failed with ESRCH, the tracee may be "not
|
||
yet fully dead", but already refusing ptrace requests. In that
|
||
case the tracee has 'R (Running)' state for a little bit
|
||
(observed in Linux 3.18). See also the note on ESRCH in the
|
||
ptrace(2) man page. Instead, check whether the LWP has any state
|
||
other than ptrace-stopped. */
|
||
|
||
/* Don't assume anything if /proc/PID/status can't be read. */
|
||
if (linux_proc_pid_is_trace_stopped_nowarn (lp->ptid.lwp ()) == 0)
|
||
{
|
||
lp->stop_reason = TARGET_STOPPED_BY_NO_REASON;
|
||
lp->status = 0;
|
||
lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
|
||
return 1;
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP
|
||
disappears while we try to resume it. */
|
||
|
||
static void
|
||
linux_resume_one_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
|
||
{
|
||
try
|
||
{
|
||
linux_resume_one_lwp_throw (lp, step, signo);
|
||
}
|
||
catch (const gdb_exception_error &ex)
|
||
{
|
||
if (!check_ptrace_stopped_lwp_gone (lp))
|
||
throw;
|
||
}
|
||
}
|
||
|
||
/* Resume LP. */
|
||
|
||
static void
|
||
resume_lwp (struct lwp_info *lp, int step, enum gdb_signal signo)
|
||
{
|
||
if (lp->stopped)
|
||
{
|
||
struct inferior *inf = find_inferior_ptid (lp->ptid);
|
||
|
||
if (inf->vfork_child != NULL)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RC: Not resuming %s (vfork parent)\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
else if (!lwp_status_pending_p (lp))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RC: Resuming sibling %s, %s, %s\n",
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
(signo != GDB_SIGNAL_0
|
||
? strsignal (gdb_signal_to_host (signo))
|
||
: "0"),
|
||
step ? "step" : "resume");
|
||
|
||
linux_resume_one_lwp (lp, step, signo);
|
||
}
|
||
else
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RC: Not resuming sibling %s (has pending)\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
}
|
||
else
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RC: Not resuming sibling %s (not stopped)\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
}
|
||
|
||
/* Callback for iterate_over_lwps. If LWP is EXCEPT, do nothing.
|
||
Resume LWP with the last stop signal, if it is in pass state. */
|
||
|
||
static int
|
||
linux_nat_resume_callback (struct lwp_info *lp, struct lwp_info *except)
|
||
{
|
||
enum gdb_signal signo = GDB_SIGNAL_0;
|
||
|
||
if (lp == except)
|
||
return 0;
|
||
|
||
if (lp->stopped)
|
||
{
|
||
struct thread_info *thread;
|
||
|
||
thread = find_thread_ptid (lp->ptid);
|
||
if (thread != NULL)
|
||
{
|
||
signo = thread->suspend.stop_signal;
|
||
thread->suspend.stop_signal = GDB_SIGNAL_0;
|
||
}
|
||
}
|
||
|
||
resume_lwp (lp, 0, signo);
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
resume_clear_callback (struct lwp_info *lp)
|
||
{
|
||
lp->resumed = 0;
|
||
lp->last_resume_kind = resume_stop;
|
||
return 0;
|
||
}
|
||
|
||
static int
|
||
resume_set_callback (struct lwp_info *lp)
|
||
{
|
||
lp->resumed = 1;
|
||
lp->last_resume_kind = resume_continue;
|
||
return 0;
|
||
}
|
||
|
||
void
|
||
linux_nat_target::resume (ptid_t ptid, int step, enum gdb_signal signo)
|
||
{
|
||
struct lwp_info *lp;
|
||
int resume_many;
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLR: Preparing to %s %s, %s, inferior_ptid %s\n",
|
||
step ? "step" : "resume",
|
||
target_pid_to_str (ptid).c_str (),
|
||
(signo != GDB_SIGNAL_0
|
||
? strsignal (gdb_signal_to_host (signo)) : "0"),
|
||
target_pid_to_str (inferior_ptid).c_str ());
|
||
|
||
/* A specific PTID means `step only this process id'. */
|
||
resume_many = (minus_one_ptid == ptid
|
||
|| ptid.is_pid ());
|
||
|
||
/* Mark the lwps we're resuming as resumed. */
|
||
iterate_over_lwps (ptid, resume_set_callback);
|
||
|
||
/* See if it's the current inferior that should be handled
|
||
specially. */
|
||
if (resume_many)
|
||
lp = find_lwp_pid (inferior_ptid);
|
||
else
|
||
lp = find_lwp_pid (ptid);
|
||
gdb_assert (lp != NULL);
|
||
|
||
/* Remember if we're stepping. */
|
||
lp->last_resume_kind = step ? resume_step : resume_continue;
|
||
|
||
/* If we have a pending wait status for this thread, there is no
|
||
point in resuming the process. But first make sure that
|
||
linux_nat_wait won't preemptively handle the event - we
|
||
should never take this short-circuit if we are going to
|
||
leave LP running, since we have skipped resuming all the
|
||
other threads. This bit of code needs to be synchronized
|
||
with linux_nat_wait. */
|
||
|
||
if (lp->status && WIFSTOPPED (lp->status))
|
||
{
|
||
if (!lp->step
|
||
&& WSTOPSIG (lp->status)
|
||
&& sigismember (&pass_mask, WSTOPSIG (lp->status)))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLR: Not short circuiting for ignored "
|
||
"status 0x%x\n", lp->status);
|
||
|
||
/* FIXME: What should we do if we are supposed to continue
|
||
this thread with a signal? */
|
||
gdb_assert (signo == GDB_SIGNAL_0);
|
||
signo = gdb_signal_from_host (WSTOPSIG (lp->status));
|
||
lp->status = 0;
|
||
}
|
||
}
|
||
|
||
if (lwp_status_pending_p (lp))
|
||
{
|
||
/* FIXME: What should we do if we are supposed to continue
|
||
this thread with a signal? */
|
||
gdb_assert (signo == GDB_SIGNAL_0);
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLR: Short circuiting for status 0x%x\n",
|
||
lp->status);
|
||
|
||
if (target_can_async_p ())
|
||
{
|
||
target_async (1);
|
||
/* Tell the event loop we have something to process. */
|
||
async_file_mark ();
|
||
}
|
||
return;
|
||
}
|
||
|
||
if (resume_many)
|
||
iterate_over_lwps (ptid, [=] (struct lwp_info *info)
|
||
{
|
||
return linux_nat_resume_callback (info, lp);
|
||
});
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLR: %s %s, %s (resume event thread)\n",
|
||
step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
(signo != GDB_SIGNAL_0
|
||
? strsignal (gdb_signal_to_host (signo)) : "0"));
|
||
|
||
linux_resume_one_lwp (lp, step, signo);
|
||
|
||
if (target_can_async_p ())
|
||
target_async (1);
|
||
}
|
||
|
||
/* Send a signal to an LWP. */
|
||
|
||
static int
|
||
kill_lwp (int lwpid, int signo)
|
||
{
|
||
int ret;
|
||
|
||
errno = 0;
|
||
ret = syscall (__NR_tkill, lwpid, signo);
|
||
if (errno == ENOSYS)
|
||
{
|
||
/* If tkill fails, then we are not using nptl threads, a
|
||
configuration we no longer support. */
|
||
perror_with_name (("tkill"));
|
||
}
|
||
return ret;
|
||
}
|
||
|
||
/* Handle a GNU/Linux syscall trap wait response. If we see a syscall
|
||
event, check if the core is interested in it: if not, ignore the
|
||
event, and keep waiting; otherwise, we need to toggle the LWP's
|
||
syscall entry/exit status, since the ptrace event itself doesn't
|
||
indicate it, and report the trap to higher layers. */
|
||
|
||
static int
|
||
linux_handle_syscall_trap (struct lwp_info *lp, int stopping)
|
||
{
|
||
struct target_waitstatus *ourstatus = &lp->waitstatus;
|
||
struct gdbarch *gdbarch = target_thread_architecture (lp->ptid);
|
||
thread_info *thread = find_thread_ptid (lp->ptid);
|
||
int syscall_number = (int) gdbarch_get_syscall_number (gdbarch, thread);
|
||
|
||
if (stopping)
|
||
{
|
||
/* If we're stopping threads, there's a SIGSTOP pending, which
|
||
makes it so that the LWP reports an immediate syscall return,
|
||
followed by the SIGSTOP. Skip seeing that "return" using
|
||
PTRACE_CONT directly, and let stop_wait_callback collect the
|
||
SIGSTOP. Later when the thread is resumed, a new syscall
|
||
entry event. If we didn't do this (and returned 0), we'd
|
||
leave a syscall entry pending, and our caller, by using
|
||
PTRACE_CONT to collect the SIGSTOP, skips the syscall return
|
||
itself. Later, when the user re-resumes this LWP, we'd see
|
||
another syscall entry event and we'd mistake it for a return.
|
||
|
||
If stop_wait_callback didn't force the SIGSTOP out of the LWP
|
||
(leaving immediately with LWP->signalled set, without issuing
|
||
a PTRACE_CONT), it would still be problematic to leave this
|
||
syscall enter pending, as later when the thread is resumed,
|
||
it would then see the same syscall exit mentioned above,
|
||
followed by the delayed SIGSTOP, while the syscall didn't
|
||
actually get to execute. It seems it would be even more
|
||
confusing to the user. */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHST: ignoring syscall %d "
|
||
"for LWP %ld (stopping threads), "
|
||
"resuming with PTRACE_CONT for SIGSTOP\n",
|
||
syscall_number,
|
||
lp->ptid.lwp ());
|
||
|
||
lp->syscall_state = TARGET_WAITKIND_IGNORE;
|
||
ptrace (PTRACE_CONT, lp->ptid.lwp (), 0, 0);
|
||
lp->stopped = 0;
|
||
return 1;
|
||
}
|
||
|
||
/* Always update the entry/return state, even if this particular
|
||
syscall isn't interesting to the core now. In async mode,
|
||
the user could install a new catchpoint for this syscall
|
||
between syscall enter/return, and we'll need to know to
|
||
report a syscall return if that happens. */
|
||
lp->syscall_state = (lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
|
||
? TARGET_WAITKIND_SYSCALL_RETURN
|
||
: TARGET_WAITKIND_SYSCALL_ENTRY);
|
||
|
||
if (catch_syscall_enabled ())
|
||
{
|
||
if (catching_syscall_number (syscall_number))
|
||
{
|
||
/* Alright, an event to report. */
|
||
ourstatus->kind = lp->syscall_state;
|
||
ourstatus->value.syscall_number = syscall_number;
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHST: stopping for %s of syscall %d"
|
||
" for LWP %ld\n",
|
||
lp->syscall_state
|
||
== TARGET_WAITKIND_SYSCALL_ENTRY
|
||
? "entry" : "return",
|
||
syscall_number,
|
||
lp->ptid.lwp ());
|
||
return 0;
|
||
}
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHST: ignoring %s of syscall %d "
|
||
"for LWP %ld\n",
|
||
lp->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY
|
||
? "entry" : "return",
|
||
syscall_number,
|
||
lp->ptid.lwp ());
|
||
}
|
||
else
|
||
{
|
||
/* If we had been syscall tracing, and hence used PT_SYSCALL
|
||
before on this LWP, it could happen that the user removes all
|
||
syscall catchpoints before we get to process this event.
|
||
There are two noteworthy issues here:
|
||
|
||
- When stopped at a syscall entry event, resuming with
|
||
PT_STEP still resumes executing the syscall and reports a
|
||
syscall return.
|
||
|
||
- Only PT_SYSCALL catches syscall enters. If we last
|
||
single-stepped this thread, then this event can't be a
|
||
syscall enter. If we last single-stepped this thread, this
|
||
has to be a syscall exit.
|
||
|
||
The points above mean that the next resume, be it PT_STEP or
|
||
PT_CONTINUE, can not trigger a syscall trace event. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHST: caught syscall event "
|
||
"with no syscall catchpoints."
|
||
" %d for LWP %ld, ignoring\n",
|
||
syscall_number,
|
||
lp->ptid.lwp ());
|
||
lp->syscall_state = TARGET_WAITKIND_IGNORE;
|
||
}
|
||
|
||
/* The core isn't interested in this event. For efficiency, avoid
|
||
stopping all threads only to have the core resume them all again.
|
||
Since we're not stopping threads, if we're still syscall tracing
|
||
and not stepping, we can't use PTRACE_CONT here, as we'd miss any
|
||
subsequent syscall. Simply resume using the inf-ptrace layer,
|
||
which knows when to use PT_SYSCALL or PT_CONTINUE. */
|
||
|
||
linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
|
||
return 1;
|
||
}
|
||
|
||
/* Handle a GNU/Linux extended wait response. If we see a clone
|
||
event, we need to add the new LWP to our list (and not report the
|
||
trap to higher layers). This function returns non-zero if the
|
||
event should be ignored and we should wait again. If STOPPING is
|
||
true, the new LWP remains stopped, otherwise it is continued. */
|
||
|
||
static int
|
||
linux_handle_extended_wait (struct lwp_info *lp, int status)
|
||
{
|
||
int pid = lp->ptid.lwp ();
|
||
struct target_waitstatus *ourstatus = &lp->waitstatus;
|
||
int event = linux_ptrace_get_extended_event (status);
|
||
|
||
/* All extended events we currently use are mid-syscall. Only
|
||
PTRACE_EVENT_STOP is delivered more like a signal-stop, but
|
||
you have to be using PTRACE_SEIZE to get that. */
|
||
lp->syscall_state = TARGET_WAITKIND_SYSCALL_ENTRY;
|
||
|
||
if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK
|
||
|| event == PTRACE_EVENT_CLONE)
|
||
{
|
||
unsigned long new_pid;
|
||
int ret;
|
||
|
||
ptrace (PTRACE_GETEVENTMSG, pid, 0, &new_pid);
|
||
|
||
/* If we haven't already seen the new PID stop, wait for it now. */
|
||
if (! pull_pid_from_list (&stopped_pids, new_pid, &status))
|
||
{
|
||
/* The new child has a pending SIGSTOP. We can't affect it until it
|
||
hits the SIGSTOP, but we're already attached. */
|
||
ret = my_waitpid (new_pid, &status, __WALL);
|
||
if (ret == -1)
|
||
perror_with_name (_("waiting for new child"));
|
||
else if (ret != new_pid)
|
||
internal_error (__FILE__, __LINE__,
|
||
_("wait returned unexpected PID %d"), ret);
|
||
else if (!WIFSTOPPED (status))
|
||
internal_error (__FILE__, __LINE__,
|
||
_("wait returned unexpected status 0x%x"), status);
|
||
}
|
||
|
||
ourstatus->value.related_pid = ptid_t (new_pid, new_pid, 0);
|
||
|
||
if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK)
|
||
{
|
||
/* The arch-specific native code may need to know about new
|
||
forks even if those end up never mapped to an
|
||
inferior. */
|
||
linux_target->low_new_fork (lp, new_pid);
|
||
}
|
||
|
||
if (event == PTRACE_EVENT_FORK
|
||
&& linux_fork_checkpointing_p (lp->ptid.pid ()))
|
||
{
|
||
/* Handle checkpointing by linux-fork.c here as a special
|
||
case. We don't want the follow-fork-mode or 'catch fork'
|
||
to interfere with this. */
|
||
|
||
/* This won't actually modify the breakpoint list, but will
|
||
physically remove the breakpoints from the child. */
|
||
detach_breakpoints (ptid_t (new_pid, new_pid, 0));
|
||
|
||
/* Retain child fork in ptrace (stopped) state. */
|
||
if (!find_fork_pid (new_pid))
|
||
add_fork (new_pid);
|
||
|
||
/* Report as spurious, so that infrun doesn't want to follow
|
||
this fork. We're actually doing an infcall in
|
||
linux-fork.c. */
|
||
ourstatus->kind = TARGET_WAITKIND_SPURIOUS;
|
||
|
||
/* Report the stop to the core. */
|
||
return 0;
|
||
}
|
||
|
||
if (event == PTRACE_EVENT_FORK)
|
||
ourstatus->kind = TARGET_WAITKIND_FORKED;
|
||
else if (event == PTRACE_EVENT_VFORK)
|
||
ourstatus->kind = TARGET_WAITKIND_VFORKED;
|
||
else if (event == PTRACE_EVENT_CLONE)
|
||
{
|
||
struct lwp_info *new_lp;
|
||
|
||
ourstatus->kind = TARGET_WAITKIND_IGNORE;
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: Got clone event "
|
||
"from LWP %d, new child is LWP %ld\n",
|
||
pid, new_pid);
|
||
|
||
new_lp = add_lwp (ptid_t (lp->ptid.pid (), new_pid, 0));
|
||
new_lp->stopped = 1;
|
||
new_lp->resumed = 1;
|
||
|
||
/* If the thread_db layer is active, let it record the user
|
||
level thread id and status, and add the thread to GDB's
|
||
list. */
|
||
if (!thread_db_notice_clone (lp->ptid, new_lp->ptid))
|
||
{
|
||
/* The process is not using thread_db. Add the LWP to
|
||
GDB's list. */
|
||
target_post_attach (new_lp->ptid.lwp ());
|
||
add_thread (new_lp->ptid);
|
||
}
|
||
|
||
/* Even if we're stopping the thread for some reason
|
||
internal to this module, from the perspective of infrun
|
||
and the user/frontend, this new thread is running until
|
||
it next reports a stop. */
|
||
set_running (new_lp->ptid, 1);
|
||
set_executing (new_lp->ptid, 1);
|
||
|
||
if (WSTOPSIG (status) != SIGSTOP)
|
||
{
|
||
/* This can happen if someone starts sending signals to
|
||
the new thread before it gets a chance to run, which
|
||
have a lower number than SIGSTOP (e.g. SIGUSR1).
|
||
This is an unlikely case, and harder to handle for
|
||
fork / vfork than for clone, so we do not try - but
|
||
we handle it for clone events here. */
|
||
|
||
new_lp->signalled = 1;
|
||
|
||
/* We created NEW_LP so it cannot yet contain STATUS. */
|
||
gdb_assert (new_lp->status == 0);
|
||
|
||
/* Save the wait status to report later. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: waitpid of new LWP %ld, "
|
||
"saving status %s\n",
|
||
(long) new_lp->ptid.lwp (),
|
||
status_to_str (status));
|
||
new_lp->status = status;
|
||
}
|
||
else if (report_thread_events)
|
||
{
|
||
new_lp->waitstatus.kind = TARGET_WAITKIND_THREAD_CREATED;
|
||
new_lp->status = status;
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
if (event == PTRACE_EVENT_EXEC)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: Got exec event from LWP %ld\n",
|
||
lp->ptid.lwp ());
|
||
|
||
ourstatus->kind = TARGET_WAITKIND_EXECD;
|
||
ourstatus->value.execd_pathname
|
||
= xstrdup (linux_proc_pid_to_exec_file (pid));
|
||
|
||
/* The thread that execed must have been resumed, but, when a
|
||
thread execs, it changes its tid to the tgid, and the old
|
||
tgid thread might have not been resumed. */
|
||
lp->resumed = 1;
|
||
return 0;
|
||
}
|
||
|
||
if (event == PTRACE_EVENT_VFORK_DONE)
|
||
{
|
||
if (current_inferior ()->waiting_for_vfork_done)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: Got expected PTRACE_EVENT_"
|
||
"VFORK_DONE from LWP %ld: stopping\n",
|
||
lp->ptid.lwp ());
|
||
|
||
ourstatus->kind = TARGET_WAITKIND_VFORK_DONE;
|
||
return 0;
|
||
}
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: Got PTRACE_EVENT_VFORK_DONE "
|
||
"from LWP %ld: ignoring\n",
|
||
lp->ptid.lwp ());
|
||
return 1;
|
||
}
|
||
|
||
internal_error (__FILE__, __LINE__,
|
||
_("unknown ptrace event %d"), event);
|
||
}
|
||
|
||
/* Suspend waiting for a signal. We're mostly interested in
|
||
SIGCHLD/SIGINT. */
|
||
|
||
static void
|
||
wait_for_signal ()
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "linux-nat: about to sigsuspend\n");
|
||
sigsuspend (&suspend_mask);
|
||
|
||
/* If the quit flag is set, it means that the user pressed Ctrl-C
|
||
and we're debugging a process that is running on a separate
|
||
terminal, so we must forward the Ctrl-C to the inferior. (If the
|
||
inferior is sharing GDB's terminal, then the Ctrl-C reaches the
|
||
inferior directly.) We must do this here because functions that
|
||
need to block waiting for a signal loop forever until there's an
|
||
event to report before returning back to the event loop. */
|
||
if (!target_terminal::is_ours ())
|
||
{
|
||
if (check_quit_flag ())
|
||
target_pass_ctrlc ();
|
||
}
|
||
}
|
||
|
||
/* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
|
||
exited. */
|
||
|
||
static int
|
||
wait_lwp (struct lwp_info *lp)
|
||
{
|
||
pid_t pid;
|
||
int status = 0;
|
||
int thread_dead = 0;
|
||
sigset_t prev_mask;
|
||
|
||
gdb_assert (!lp->stopped);
|
||
gdb_assert (lp->status == 0);
|
||
|
||
/* Make sure SIGCHLD is blocked for sigsuspend avoiding a race below. */
|
||
block_child_signals (&prev_mask);
|
||
|
||
for (;;)
|
||
{
|
||
pid = my_waitpid (lp->ptid.lwp (), &status, __WALL | WNOHANG);
|
||
if (pid == -1 && errno == ECHILD)
|
||
{
|
||
/* The thread has previously exited. We need to delete it
|
||
now because if this was a non-leader thread execing, we
|
||
won't get an exit event. See comments on exec events at
|
||
the top of the file. */
|
||
thread_dead = 1;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
if (pid != 0)
|
||
break;
|
||
|
||
/* Bugs 10970, 12702.
|
||
Thread group leader may have exited in which case we'll lock up in
|
||
waitpid if there are other threads, even if they are all zombies too.
|
||
Basically, we're not supposed to use waitpid this way.
|
||
tkill(pid,0) cannot be used here as it gets ESRCH for both
|
||
for zombie and running processes.
|
||
|
||
As a workaround, check if we're waiting for the thread group leader and
|
||
if it's a zombie, and avoid calling waitpid if it is.
|
||
|
||
This is racy, what if the tgl becomes a zombie right after we check?
|
||
Therefore always use WNOHANG with sigsuspend - it is equivalent to
|
||
waiting waitpid but linux_proc_pid_is_zombie is safe this way. */
|
||
|
||
if (lp->ptid.pid () == lp->ptid.lwp ()
|
||
&& linux_proc_pid_is_zombie (lp->ptid.lwp ()))
|
||
{
|
||
thread_dead = 1;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"WL: Thread group leader %s vanished.\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
break;
|
||
}
|
||
|
||
/* Wait for next SIGCHLD and try again. This may let SIGCHLD handlers
|
||
get invoked despite our caller had them intentionally blocked by
|
||
block_child_signals. This is sensitive only to the loop of
|
||
linux_nat_wait_1 and there if we get called my_waitpid gets called
|
||
again before it gets to sigsuspend so we can safely let the handlers
|
||
get executed here. */
|
||
wait_for_signal ();
|
||
}
|
||
|
||
restore_child_signals_mask (&prev_mask);
|
||
|
||
if (!thread_dead)
|
||
{
|
||
gdb_assert (pid == lp->ptid.lwp ());
|
||
|
||
if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"WL: waitpid %s received %s\n",
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
status_to_str (status));
|
||
}
|
||
|
||
/* Check if the thread has exited. */
|
||
if (WIFEXITED (status) || WIFSIGNALED (status))
|
||
{
|
||
if (report_thread_events
|
||
|| lp->ptid.pid () == lp->ptid.lwp ())
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "WL: LWP %d exited.\n",
|
||
lp->ptid.pid ());
|
||
|
||
/* If this is the leader exiting, it means the whole
|
||
process is gone. Store the status to report to the
|
||
core. Store it in lp->waitstatus, because lp->status
|
||
would be ambiguous (W_EXITCODE(0,0) == 0). */
|
||
store_waitstatus (&lp->waitstatus, status);
|
||
return 0;
|
||
}
|
||
|
||
thread_dead = 1;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
}
|
||
|
||
if (thread_dead)
|
||
{
|
||
exit_lwp (lp);
|
||
return 0;
|
||
}
|
||
|
||
gdb_assert (WIFSTOPPED (status));
|
||
lp->stopped = 1;
|
||
|
||
if (lp->must_set_ptrace_flags)
|
||
{
|
||
struct inferior *inf = find_inferior_pid (lp->ptid.pid ());
|
||
int options = linux_nat_ptrace_options (inf->attach_flag);
|
||
|
||
linux_enable_event_reporting (lp->ptid.lwp (), options);
|
||
lp->must_set_ptrace_flags = 0;
|
||
}
|
||
|
||
/* Handle GNU/Linux's syscall SIGTRAPs. */
|
||
if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
|
||
{
|
||
/* No longer need the sysgood bit. The ptrace event ends up
|
||
recorded in lp->waitstatus if we care for it. We can carry
|
||
on handling the event like a regular SIGTRAP from here
|
||
on. */
|
||
status = W_STOPCODE (SIGTRAP);
|
||
if (linux_handle_syscall_trap (lp, 1))
|
||
return wait_lwp (lp);
|
||
}
|
||
else
|
||
{
|
||
/* Almost all other ptrace-stops are known to be outside of system
|
||
calls, with further exceptions in linux_handle_extended_wait. */
|
||
lp->syscall_state = TARGET_WAITKIND_IGNORE;
|
||
}
|
||
|
||
/* Handle GNU/Linux's extended waitstatus for trace events. */
|
||
if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
|
||
&& linux_is_extended_waitstatus (status))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"WL: Handling extended status 0x%06x\n",
|
||
status);
|
||
linux_handle_extended_wait (lp, status);
|
||
return 0;
|
||
}
|
||
|
||
return status;
|
||
}
|
||
|
||
/* Send a SIGSTOP to LP. */
|
||
|
||
static int
|
||
stop_callback (struct lwp_info *lp)
|
||
{
|
||
if (!lp->stopped && !lp->signalled)
|
||
{
|
||
int ret;
|
||
|
||
if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SC: kill %s **<SIGSTOP>**\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
errno = 0;
|
||
ret = kill_lwp (lp->ptid.lwp (), SIGSTOP);
|
||
if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SC: lwp kill %d %s\n",
|
||
ret,
|
||
errno ? safe_strerror (errno) : "ERRNO-OK");
|
||
}
|
||
|
||
lp->signalled = 1;
|
||
gdb_assert (lp->status == 0);
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Request a stop on LWP. */
|
||
|
||
void
|
||
linux_stop_lwp (struct lwp_info *lwp)
|
||
{
|
||
stop_callback (lwp);
|
||
}
|
||
|
||
/* See linux-nat.h */
|
||
|
||
void
|
||
linux_stop_and_wait_all_lwps (void)
|
||
{
|
||
/* Stop all LWP's ... */
|
||
iterate_over_lwps (minus_one_ptid, stop_callback);
|
||
|
||
/* ... and wait until all of them have reported back that
|
||
they're no longer running. */
|
||
iterate_over_lwps (minus_one_ptid, stop_wait_callback);
|
||
}
|
||
|
||
/* See linux-nat.h */
|
||
|
||
void
|
||
linux_unstop_all_lwps (void)
|
||
{
|
||
iterate_over_lwps (minus_one_ptid,
|
||
[] (struct lwp_info *info)
|
||
{
|
||
return resume_stopped_resumed_lwps (info, minus_one_ptid);
|
||
});
|
||
}
|
||
|
||
/* Return non-zero if LWP PID has a pending SIGINT. */
|
||
|
||
static int
|
||
linux_nat_has_pending_sigint (int pid)
|
||
{
|
||
sigset_t pending, blocked, ignored;
|
||
|
||
linux_proc_pending_signals (pid, &pending, &blocked, &ignored);
|
||
|
||
if (sigismember (&pending, SIGINT)
|
||
&& !sigismember (&ignored, SIGINT))
|
||
return 1;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Set a flag in LP indicating that we should ignore its next SIGINT. */
|
||
|
||
static int
|
||
set_ignore_sigint (struct lwp_info *lp)
|
||
{
|
||
/* If a thread has a pending SIGINT, consume it; otherwise, set a
|
||
flag to consume the next one. */
|
||
if (lp->stopped && lp->status != 0 && WIFSTOPPED (lp->status)
|
||
&& WSTOPSIG (lp->status) == SIGINT)
|
||
lp->status = 0;
|
||
else
|
||
lp->ignore_sigint = 1;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* If LP does not have a SIGINT pending, then clear the ignore_sigint flag.
|
||
This function is called after we know the LWP has stopped; if the LWP
|
||
stopped before the expected SIGINT was delivered, then it will never have
|
||
arrived. Also, if the signal was delivered to a shared queue and consumed
|
||
by a different thread, it will never be delivered to this LWP. */
|
||
|
||
static void
|
||
maybe_clear_ignore_sigint (struct lwp_info *lp)
|
||
{
|
||
if (!lp->ignore_sigint)
|
||
return;
|
||
|
||
if (!linux_nat_has_pending_sigint (lp->ptid.lwp ()))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"MCIS: Clearing bogus flag for %s\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
lp->ignore_sigint = 0;
|
||
}
|
||
}
|
||
|
||
/* Fetch the possible triggered data watchpoint info and store it in
|
||
LP.
|
||
|
||
On some archs, like x86, that use debug registers to set
|
||
watchpoints, it's possible that the way to know which watched
|
||
address trapped, is to check the register that is used to select
|
||
which address to watch. Problem is, between setting the watchpoint
|
||
and reading back which data address trapped, the user may change
|
||
the set of watchpoints, and, as a consequence, GDB changes the
|
||
debug registers in the inferior. To avoid reading back a stale
|
||
stopped-data-address when that happens, we cache in LP the fact
|
||
that a watchpoint trapped, and the corresponding data address, as
|
||
soon as we see LP stop with a SIGTRAP. If GDB changes the debug
|
||
registers meanwhile, we have the cached data we can rely on. */
|
||
|
||
static int
|
||
check_stopped_by_watchpoint (struct lwp_info *lp)
|
||
{
|
||
scoped_restore save_inferior_ptid = make_scoped_restore (&inferior_ptid);
|
||
inferior_ptid = lp->ptid;
|
||
|
||
if (linux_target->low_stopped_by_watchpoint ())
|
||
{
|
||
lp->stop_reason = TARGET_STOPPED_BY_WATCHPOINT;
|
||
lp->stopped_data_address_p
|
||
= linux_target->low_stopped_data_address (&lp->stopped_data_address);
|
||
}
|
||
|
||
return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
|
||
}
|
||
|
||
/* Returns true if the LWP had stopped for a watchpoint. */
|
||
|
||
bool
|
||
linux_nat_target::stopped_by_watchpoint ()
|
||
{
|
||
struct lwp_info *lp = find_lwp_pid (inferior_ptid);
|
||
|
||
gdb_assert (lp != NULL);
|
||
|
||
return lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT;
|
||
}
|
||
|
||
bool
|
||
linux_nat_target::stopped_data_address (CORE_ADDR *addr_p)
|
||
{
|
||
struct lwp_info *lp = find_lwp_pid (inferior_ptid);
|
||
|
||
gdb_assert (lp != NULL);
|
||
|
||
*addr_p = lp->stopped_data_address;
|
||
|
||
return lp->stopped_data_address_p;
|
||
}
|
||
|
||
/* Commonly any breakpoint / watchpoint generate only SIGTRAP. */
|
||
|
||
bool
|
||
linux_nat_target::low_status_is_event (int status)
|
||
{
|
||
return WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP;
|
||
}
|
||
|
||
/* Wait until LP is stopped. */
|
||
|
||
static int
|
||
stop_wait_callback (struct lwp_info *lp)
|
||
{
|
||
struct inferior *inf = find_inferior_ptid (lp->ptid);
|
||
|
||
/* If this is a vfork parent, bail out, it is not going to report
|
||
any SIGSTOP until the vfork is done with. */
|
||
if (inf->vfork_child != NULL)
|
||
return 0;
|
||
|
||
if (!lp->stopped)
|
||
{
|
||
int status;
|
||
|
||
status = wait_lwp (lp);
|
||
if (status == 0)
|
||
return 0;
|
||
|
||
if (lp->ignore_sigint && WIFSTOPPED (status)
|
||
&& WSTOPSIG (status) == SIGINT)
|
||
{
|
||
lp->ignore_sigint = 0;
|
||
|
||
errno = 0;
|
||
ptrace (PTRACE_CONT, lp->ptid.lwp (), 0, 0);
|
||
lp->stopped = 0;
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"PTRACE_CONT %s, 0, 0 (%s) "
|
||
"(discarding SIGINT)\n",
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
errno ? safe_strerror (errno) : "OK");
|
||
|
||
return stop_wait_callback (lp);
|
||
}
|
||
|
||
maybe_clear_ignore_sigint (lp);
|
||
|
||
if (WSTOPSIG (status) != SIGSTOP)
|
||
{
|
||
/* The thread was stopped with a signal other than SIGSTOP. */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SWC: Pending event %s in %s\n",
|
||
status_to_str ((int) status),
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
|
||
/* Save the sigtrap event. */
|
||
lp->status = status;
|
||
gdb_assert (lp->signalled);
|
||
save_stop_reason (lp);
|
||
}
|
||
else
|
||
{
|
||
/* We caught the SIGSTOP that we intended to catch. */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SWC: Expected SIGSTOP caught for %s.\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
|
||
lp->signalled = 0;
|
||
|
||
/* If we are waiting for this stop so we can report the thread
|
||
stopped then we need to record this status. Otherwise, we can
|
||
now discard this stop event. */
|
||
if (lp->last_resume_kind == resume_stop)
|
||
{
|
||
lp->status = status;
|
||
save_stop_reason (lp);
|
||
}
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Return non-zero if LP has a wait status pending. Discard the
|
||
pending event and resume the LWP if the event that originally
|
||
caused the stop became uninteresting. */
|
||
|
||
static int
|
||
status_callback (struct lwp_info *lp)
|
||
{
|
||
/* Only report a pending wait status if we pretend that this has
|
||
indeed been resumed. */
|
||
if (!lp->resumed)
|
||
return 0;
|
||
|
||
if (!lwp_status_pending_p (lp))
|
||
return 0;
|
||
|
||
if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
|
||
|| lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
|
||
{
|
||
struct regcache *regcache = get_thread_regcache (lp->ptid);
|
||
CORE_ADDR pc;
|
||
int discard = 0;
|
||
|
||
pc = regcache_read_pc (regcache);
|
||
|
||
if (pc != lp->stop_pc)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SC: PC of %s changed. was=%s, now=%s\n",
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
paddress (target_gdbarch (), lp->stop_pc),
|
||
paddress (target_gdbarch (), pc));
|
||
discard = 1;
|
||
}
|
||
|
||
#if !USE_SIGTRAP_SIGINFO
|
||
else if (!breakpoint_inserted_here_p (regcache->aspace (), pc))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SC: previous breakpoint of %s, at %s gone\n",
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
paddress (target_gdbarch (), lp->stop_pc));
|
||
|
||
discard = 1;
|
||
}
|
||
#endif
|
||
|
||
if (discard)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SC: pending event of %s cancelled.\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
|
||
lp->status = 0;
|
||
linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Count the LWP's that have had events. */
|
||
|
||
static int
|
||
count_events_callback (struct lwp_info *lp, int *count)
|
||
{
|
||
gdb_assert (count != NULL);
|
||
|
||
/* Select only resumed LWPs that have an event pending. */
|
||
if (lp->resumed && lwp_status_pending_p (lp))
|
||
(*count)++;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Select the LWP (if any) that is currently being single-stepped. */
|
||
|
||
static int
|
||
select_singlestep_lwp_callback (struct lwp_info *lp)
|
||
{
|
||
if (lp->last_resume_kind == resume_step
|
||
&& lp->status != 0)
|
||
return 1;
|
||
else
|
||
return 0;
|
||
}
|
||
|
||
/* Returns true if LP has a status pending. */
|
||
|
||
static int
|
||
lwp_status_pending_p (struct lwp_info *lp)
|
||
{
|
||
/* We check for lp->waitstatus in addition to lp->status, because we
|
||
can have pending process exits recorded in lp->status and
|
||
W_EXITCODE(0,0) happens to be 0. */
|
||
return lp->status != 0 || lp->waitstatus.kind != TARGET_WAITKIND_IGNORE;
|
||
}
|
||
|
||
/* Select the Nth LWP that has had an event. */
|
||
|
||
static int
|
||
select_event_lwp_callback (struct lwp_info *lp, int *selector)
|
||
{
|
||
gdb_assert (selector != NULL);
|
||
|
||
/* Select only resumed LWPs that have an event pending. */
|
||
if (lp->resumed && lwp_status_pending_p (lp))
|
||
if ((*selector)-- == 0)
|
||
return 1;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Called when the LWP stopped for a signal/trap. If it stopped for a
|
||
trap check what caused it (breakpoint, watchpoint, trace, etc.),
|
||
and save the result in the LWP's stop_reason field. If it stopped
|
||
for a breakpoint, decrement the PC if necessary on the lwp's
|
||
architecture. */
|
||
|
||
static void
|
||
save_stop_reason (struct lwp_info *lp)
|
||
{
|
||
struct regcache *regcache;
|
||
struct gdbarch *gdbarch;
|
||
CORE_ADDR pc;
|
||
CORE_ADDR sw_bp_pc;
|
||
#if USE_SIGTRAP_SIGINFO
|
||
siginfo_t siginfo;
|
||
#endif
|
||
|
||
gdb_assert (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON);
|
||
gdb_assert (lp->status != 0);
|
||
|
||
if (!linux_target->low_status_is_event (lp->status))
|
||
return;
|
||
|
||
regcache = get_thread_regcache (lp->ptid);
|
||
gdbarch = regcache->arch ();
|
||
|
||
pc = regcache_read_pc (regcache);
|
||
sw_bp_pc = pc - gdbarch_decr_pc_after_break (gdbarch);
|
||
|
||
#if USE_SIGTRAP_SIGINFO
|
||
if (linux_nat_get_siginfo (lp->ptid, &siginfo))
|
||
{
|
||
if (siginfo.si_signo == SIGTRAP)
|
||
{
|
||
if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code)
|
||
&& GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
|
||
{
|
||
/* The si_code is ambiguous on this arch -- check debug
|
||
registers. */
|
||
if (!check_stopped_by_watchpoint (lp))
|
||
lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
|
||
}
|
||
else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code))
|
||
{
|
||
/* If we determine the LWP stopped for a SW breakpoint,
|
||
trust it. Particularly don't check watchpoint
|
||
registers, because at least on s390, we'd find
|
||
stopped-by-watchpoint as long as there's a watchpoint
|
||
set. */
|
||
lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
|
||
}
|
||
else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
|
||
{
|
||
/* This can indicate either a hardware breakpoint or
|
||
hardware watchpoint. Check debug registers. */
|
||
if (!check_stopped_by_watchpoint (lp))
|
||
lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
|
||
}
|
||
else if (siginfo.si_code == TRAP_TRACE)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CSBB: %s stopped by trace\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
|
||
/* We may have single stepped an instruction that
|
||
triggered a watchpoint. In that case, on some
|
||
architectures (such as x86), instead of TRAP_HWBKPT,
|
||
si_code indicates TRAP_TRACE, and we need to check
|
||
the debug registers separately. */
|
||
check_stopped_by_watchpoint (lp);
|
||
}
|
||
}
|
||
}
|
||
#else
|
||
if ((!lp->step || lp->stop_pc == sw_bp_pc)
|
||
&& software_breakpoint_inserted_here_p (regcache->aspace (),
|
||
sw_bp_pc))
|
||
{
|
||
/* The LWP was either continued, or stepped a software
|
||
breakpoint instruction. */
|
||
lp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT;
|
||
}
|
||
|
||
if (hardware_breakpoint_inserted_here_p (regcache->aspace (), pc))
|
||
lp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT;
|
||
|
||
if (lp->stop_reason == TARGET_STOPPED_BY_NO_REASON)
|
||
check_stopped_by_watchpoint (lp);
|
||
#endif
|
||
|
||
if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CSBB: %s stopped by software breakpoint\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
|
||
/* Back up the PC if necessary. */
|
||
if (pc != sw_bp_pc)
|
||
regcache_write_pc (regcache, sw_bp_pc);
|
||
|
||
/* Update this so we record the correct stop PC below. */
|
||
pc = sw_bp_pc;
|
||
}
|
||
else if (lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CSBB: %s stopped by hardware breakpoint\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
else if (lp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CSBB: %s stopped by hardware watchpoint\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
|
||
lp->stop_pc = pc;
|
||
}
|
||
|
||
|
||
/* Returns true if the LWP had stopped for a software breakpoint. */
|
||
|
||
bool
|
||
linux_nat_target::stopped_by_sw_breakpoint ()
|
||
{
|
||
struct lwp_info *lp = find_lwp_pid (inferior_ptid);
|
||
|
||
gdb_assert (lp != NULL);
|
||
|
||
return lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT;
|
||
}
|
||
|
||
/* Implement the supports_stopped_by_sw_breakpoint method. */
|
||
|
||
bool
|
||
linux_nat_target::supports_stopped_by_sw_breakpoint ()
|
||
{
|
||
return USE_SIGTRAP_SIGINFO;
|
||
}
|
||
|
||
/* Returns true if the LWP had stopped for a hardware
|
||
breakpoint/watchpoint. */
|
||
|
||
bool
|
||
linux_nat_target::stopped_by_hw_breakpoint ()
|
||
{
|
||
struct lwp_info *lp = find_lwp_pid (inferior_ptid);
|
||
|
||
gdb_assert (lp != NULL);
|
||
|
||
return lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT;
|
||
}
|
||
|
||
/* Implement the supports_stopped_by_hw_breakpoint method. */
|
||
|
||
bool
|
||
linux_nat_target::supports_stopped_by_hw_breakpoint ()
|
||
{
|
||
return USE_SIGTRAP_SIGINFO;
|
||
}
|
||
|
||
/* Select one LWP out of those that have events pending. */
|
||
|
||
static void
|
||
select_event_lwp (ptid_t filter, struct lwp_info **orig_lp, int *status)
|
||
{
|
||
int num_events = 0;
|
||
int random_selector;
|
||
struct lwp_info *event_lp = NULL;
|
||
|
||
/* Record the wait status for the original LWP. */
|
||
(*orig_lp)->status = *status;
|
||
|
||
/* In all-stop, give preference to the LWP that is being
|
||
single-stepped. There will be at most one, and it will be the
|
||
LWP that the core is most interested in. If we didn't do this,
|
||
then we'd have to handle pending step SIGTRAPs somehow in case
|
||
the core later continues the previously-stepped thread, as
|
||
otherwise we'd report the pending SIGTRAP then, and the core, not
|
||
having stepped the thread, wouldn't understand what the trap was
|
||
for, and therefore would report it to the user as a random
|
||
signal. */
|
||
if (!target_is_non_stop_p ())
|
||
{
|
||
event_lp = iterate_over_lwps (filter, select_singlestep_lwp_callback);
|
||
if (event_lp != NULL)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SEL: Select single-step %s\n",
|
||
target_pid_to_str (event_lp->ptid).c_str ());
|
||
}
|
||
}
|
||
|
||
if (event_lp == NULL)
|
||
{
|
||
/* Pick one at random, out of those which have had events. */
|
||
|
||
/* First see how many events we have. */
|
||
iterate_over_lwps (filter,
|
||
[&] (struct lwp_info *info)
|
||
{
|
||
return count_events_callback (info, &num_events);
|
||
});
|
||
gdb_assert (num_events > 0);
|
||
|
||
/* Now randomly pick a LWP out of those that have had
|
||
events. */
|
||
random_selector = (int)
|
||
((num_events * (double) rand ()) / (RAND_MAX + 1.0));
|
||
|
||
if (debug_linux_nat && num_events > 1)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"SEL: Found %d events, selecting #%d\n",
|
||
num_events, random_selector);
|
||
|
||
event_lp
|
||
= (iterate_over_lwps
|
||
(filter,
|
||
[&] (struct lwp_info *info)
|
||
{
|
||
return select_event_lwp_callback (info,
|
||
&random_selector);
|
||
}));
|
||
}
|
||
|
||
if (event_lp != NULL)
|
||
{
|
||
/* Switch the event LWP. */
|
||
*orig_lp = event_lp;
|
||
*status = event_lp->status;
|
||
}
|
||
|
||
/* Flush the wait status for the event LWP. */
|
||
(*orig_lp)->status = 0;
|
||
}
|
||
|
||
/* Return non-zero if LP has been resumed. */
|
||
|
||
static int
|
||
resumed_callback (struct lwp_info *lp)
|
||
{
|
||
return lp->resumed;
|
||
}
|
||
|
||
/* Check if we should go on and pass this event to common code.
|
||
Return the affected lwp if we are, or NULL otherwise. */
|
||
|
||
static struct lwp_info *
|
||
linux_nat_filter_event (int lwpid, int status)
|
||
{
|
||
struct lwp_info *lp;
|
||
int event = linux_ptrace_get_extended_event (status);
|
||
|
||
lp = find_lwp_pid (ptid_t (lwpid));
|
||
|
||
/* Check for stop events reported by a process we didn't already
|
||
know about - anything not already in our LWP list.
|
||
|
||
If we're expecting to receive stopped processes after
|
||
fork, vfork, and clone events, then we'll just add the
|
||
new one to our list and go back to waiting for the event
|
||
to be reported - the stopped process might be returned
|
||
from waitpid before or after the event is.
|
||
|
||
But note the case of a non-leader thread exec'ing after the
|
||
leader having exited, and gone from our lists. The non-leader
|
||
thread changes its tid to the tgid. */
|
||
|
||
if (WIFSTOPPED (status) && lp == NULL
|
||
&& (WSTOPSIG (status) == SIGTRAP && event == PTRACE_EVENT_EXEC))
|
||
{
|
||
/* A multi-thread exec after we had seen the leader exiting. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: Re-adding thread group leader LWP %d.\n",
|
||
lwpid);
|
||
|
||
lp = add_lwp (ptid_t (lwpid, lwpid, 0));
|
||
lp->stopped = 1;
|
||
lp->resumed = 1;
|
||
add_thread (lp->ptid);
|
||
}
|
||
|
||
if (WIFSTOPPED (status) && !lp)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LHEW: saving LWP %ld status %s in stopped_pids list\n",
|
||
(long) lwpid, status_to_str (status));
|
||
add_to_pid_list (&stopped_pids, lwpid, status);
|
||
return NULL;
|
||
}
|
||
|
||
/* Make sure we don't report an event for the exit of an LWP not in
|
||
our list, i.e. not part of the current process. This can happen
|
||
if we detach from a program we originally forked and then it
|
||
exits. */
|
||
if (!WIFSTOPPED (status) && !lp)
|
||
return NULL;
|
||
|
||
/* This LWP is stopped now. (And if dead, this prevents it from
|
||
ever being continued.) */
|
||
lp->stopped = 1;
|
||
|
||
if (WIFSTOPPED (status) && lp->must_set_ptrace_flags)
|
||
{
|
||
struct inferior *inf = find_inferior_pid (lp->ptid.pid ());
|
||
int options = linux_nat_ptrace_options (inf->attach_flag);
|
||
|
||
linux_enable_event_reporting (lp->ptid.lwp (), options);
|
||
lp->must_set_ptrace_flags = 0;
|
||
}
|
||
|
||
/* Handle GNU/Linux's syscall SIGTRAPs. */
|
||
if (WIFSTOPPED (status) && WSTOPSIG (status) == SYSCALL_SIGTRAP)
|
||
{
|
||
/* No longer need the sysgood bit. The ptrace event ends up
|
||
recorded in lp->waitstatus if we care for it. We can carry
|
||
on handling the event like a regular SIGTRAP from here
|
||
on. */
|
||
status = W_STOPCODE (SIGTRAP);
|
||
if (linux_handle_syscall_trap (lp, 0))
|
||
return NULL;
|
||
}
|
||
else
|
||
{
|
||
/* Almost all other ptrace-stops are known to be outside of system
|
||
calls, with further exceptions in linux_handle_extended_wait. */
|
||
lp->syscall_state = TARGET_WAITKIND_IGNORE;
|
||
}
|
||
|
||
/* Handle GNU/Linux's extended waitstatus for trace events. */
|
||
if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
|
||
&& linux_is_extended_waitstatus (status))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: Handling extended status 0x%06x\n",
|
||
status);
|
||
if (linux_handle_extended_wait (lp, status))
|
||
return NULL;
|
||
}
|
||
|
||
/* Check if the thread has exited. */
|
||
if (WIFEXITED (status) || WIFSIGNALED (status))
|
||
{
|
||
if (!report_thread_events
|
||
&& num_lwps (lp->ptid.pid ()) > 1)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: %s exited.\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
|
||
/* If there is at least one more LWP, then the exit signal
|
||
was not the end of the debugged application and should be
|
||
ignored. */
|
||
exit_lwp (lp);
|
||
return NULL;
|
||
}
|
||
|
||
/* Note that even if the leader was ptrace-stopped, it can still
|
||
exit, if e.g., some other thread brings down the whole
|
||
process (calls `exit'). So don't assert that the lwp is
|
||
resumed. */
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LWP %ld exited (resumed=%d)\n",
|
||
lp->ptid.lwp (), lp->resumed);
|
||
|
||
/* Dead LWP's aren't expected to reported a pending sigstop. */
|
||
lp->signalled = 0;
|
||
|
||
/* Store the pending event in the waitstatus, because
|
||
W_EXITCODE(0,0) == 0. */
|
||
store_waitstatus (&lp->waitstatus, status);
|
||
return lp;
|
||
}
|
||
|
||
/* Make sure we don't report a SIGSTOP that we sent ourselves in
|
||
an attempt to stop an LWP. */
|
||
if (lp->signalled
|
||
&& WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
|
||
{
|
||
lp->signalled = 0;
|
||
|
||
if (lp->last_resume_kind == resume_stop)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: resume_stop SIGSTOP caught for %s.\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
else
|
||
{
|
||
/* This is a delayed SIGSTOP. Filter out the event. */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n",
|
||
lp->step ?
|
||
"PTRACE_SINGLESTEP" : "PTRACE_CONT",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
|
||
linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
|
||
gdb_assert (lp->resumed);
|
||
return NULL;
|
||
}
|
||
}
|
||
|
||
/* Make sure we don't report a SIGINT that we have already displayed
|
||
for another thread. */
|
||
if (lp->ignore_sigint
|
||
&& WIFSTOPPED (status) && WSTOPSIG (status) == SIGINT)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: Delayed SIGINT caught for %s.\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
|
||
/* This is a delayed SIGINT. */
|
||
lp->ignore_sigint = 0;
|
||
|
||
linux_resume_one_lwp (lp, lp->step, GDB_SIGNAL_0);
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: %s %s, 0, 0 (discard SIGINT)\n",
|
||
lp->step ?
|
||
"PTRACE_SINGLESTEP" : "PTRACE_CONT",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
gdb_assert (lp->resumed);
|
||
|
||
/* Discard the event. */
|
||
return NULL;
|
||
}
|
||
|
||
/* Don't report signals that GDB isn't interested in, such as
|
||
signals that are neither printed nor stopped upon. Stopping all
|
||
threads can be a bit time-consuming so if we want decent
|
||
performance with heavily multi-threaded programs, especially when
|
||
they're using a high frequency timer, we'd better avoid it if we
|
||
can. */
|
||
if (WIFSTOPPED (status))
|
||
{
|
||
enum gdb_signal signo = gdb_signal_from_host (WSTOPSIG (status));
|
||
|
||
if (!target_is_non_stop_p ())
|
||
{
|
||
/* Only do the below in all-stop, as we currently use SIGSTOP
|
||
to implement target_stop (see linux_nat_stop) in
|
||
non-stop. */
|
||
if (signo == GDB_SIGNAL_INT && signal_pass_state (signo) == 0)
|
||
{
|
||
/* If ^C/BREAK is typed at the tty/console, SIGINT gets
|
||
forwarded to the entire process group, that is, all LWPs
|
||
will receive it - unless they're using CLONE_THREAD to
|
||
share signals. Since we only want to report it once, we
|
||
mark it as ignored for all LWPs except this one. */
|
||
iterate_over_lwps (ptid_t (lp->ptid.pid ()), set_ignore_sigint);
|
||
lp->ignore_sigint = 0;
|
||
}
|
||
else
|
||
maybe_clear_ignore_sigint (lp);
|
||
}
|
||
|
||
/* When using hardware single-step, we need to report every signal.
|
||
Otherwise, signals in pass_mask may be short-circuited
|
||
except signals that might be caused by a breakpoint, or SIGSTOP
|
||
if we sent the SIGSTOP and are waiting for it to arrive. */
|
||
if (!lp->step
|
||
&& WSTOPSIG (status) && sigismember (&pass_mask, WSTOPSIG (status))
|
||
&& (WSTOPSIG (status) != SIGSTOP
|
||
|| !find_thread_ptid (lp->ptid)->stop_requested)
|
||
&& !linux_wstatus_maybe_breakpoint (status))
|
||
{
|
||
linux_resume_one_lwp (lp, lp->step, signo);
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: %s %s, %s (preempt 'handle')\n",
|
||
lp->step ?
|
||
"PTRACE_SINGLESTEP" : "PTRACE_CONT",
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
(signo != GDB_SIGNAL_0
|
||
? strsignal (gdb_signal_to_host (signo))
|
||
: "0"));
|
||
return NULL;
|
||
}
|
||
}
|
||
|
||
/* An interesting event. */
|
||
gdb_assert (lp);
|
||
lp->status = status;
|
||
save_stop_reason (lp);
|
||
return lp;
|
||
}
|
||
|
||
/* Detect zombie thread group leaders, and "exit" them. We can't reap
|
||
their exits until all other threads in the group have exited. */
|
||
|
||
static void
|
||
check_zombie_leaders (void)
|
||
{
|
||
for (inferior *inf : all_inferiors ())
|
||
{
|
||
struct lwp_info *leader_lp;
|
||
|
||
if (inf->pid == 0)
|
||
continue;
|
||
|
||
leader_lp = find_lwp_pid (ptid_t (inf->pid));
|
||
if (leader_lp != NULL
|
||
/* Check if there are other threads in the group, as we may
|
||
have raced with the inferior simply exiting. */
|
||
&& num_lwps (inf->pid) > 1
|
||
&& linux_proc_pid_is_zombie (inf->pid))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CZL: Thread group leader %d zombie "
|
||
"(it exited, or another thread execd).\n",
|
||
inf->pid);
|
||
|
||
/* A leader zombie can mean one of two things:
|
||
|
||
- It exited, and there's an exit status pending
|
||
available, or only the leader exited (not the whole
|
||
program). In the latter case, we can't waitpid the
|
||
leader's exit status until all other threads are gone.
|
||
|
||
- There are 3 or more threads in the group, and a thread
|
||
other than the leader exec'd. See comments on exec
|
||
events at the top of the file. We could try
|
||
distinguishing the exit and exec cases, by waiting once
|
||
more, and seeing if something comes out, but it doesn't
|
||
sound useful. The previous leader _does_ go away, and
|
||
we'll re-add the new one once we see the exec event
|
||
(which is just the same as what would happen if the
|
||
previous leader did exit voluntarily before some other
|
||
thread execs). */
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"CZL: Thread group leader %d vanished.\n",
|
||
inf->pid);
|
||
exit_lwp (leader_lp);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Convenience function that is called when the kernel reports an exit
|
||
event. This decides whether to report the event to GDB as a
|
||
process exit event, a thread exit event, or to suppress the
|
||
event. */
|
||
|
||
static ptid_t
|
||
filter_exit_event (struct lwp_info *event_child,
|
||
struct target_waitstatus *ourstatus)
|
||
{
|
||
ptid_t ptid = event_child->ptid;
|
||
|
||
if (num_lwps (ptid.pid ()) > 1)
|
||
{
|
||
if (report_thread_events)
|
||
ourstatus->kind = TARGET_WAITKIND_THREAD_EXITED;
|
||
else
|
||
ourstatus->kind = TARGET_WAITKIND_IGNORE;
|
||
|
||
exit_lwp (event_child);
|
||
}
|
||
|
||
return ptid;
|
||
}
|
||
|
||
static ptid_t
|
||
linux_nat_wait_1 (ptid_t ptid, struct target_waitstatus *ourstatus,
|
||
int target_options)
|
||
{
|
||
sigset_t prev_mask;
|
||
enum resume_kind last_resume_kind;
|
||
struct lwp_info *lp;
|
||
int status;
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "LLW: enter\n");
|
||
|
||
/* The first time we get here after starting a new inferior, we may
|
||
not have added it to the LWP list yet - this is the earliest
|
||
moment at which we know its PID. */
|
||
if (inferior_ptid.is_pid ())
|
||
{
|
||
/* Upgrade the main thread's ptid. */
|
||
thread_change_ptid (inferior_ptid,
|
||
ptid_t (inferior_ptid.pid (),
|
||
inferior_ptid.pid (), 0));
|
||
|
||
lp = add_initial_lwp (inferior_ptid);
|
||
lp->resumed = 1;
|
||
}
|
||
|
||
/* Make sure SIGCHLD is blocked until the sigsuspend below. */
|
||
block_child_signals (&prev_mask);
|
||
|
||
/* First check if there is a LWP with a wait status pending. */
|
||
lp = iterate_over_lwps (ptid, status_callback);
|
||
if (lp != NULL)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: Using pending wait status %s for %s.\n",
|
||
status_to_str (lp->status),
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
|
||
/* But if we don't find a pending event, we'll have to wait. Always
|
||
pull all events out of the kernel. We'll randomly select an
|
||
event LWP out of all that have events, to prevent starvation. */
|
||
|
||
while (lp == NULL)
|
||
{
|
||
pid_t lwpid;
|
||
|
||
/* Always use -1 and WNOHANG, due to couple of a kernel/ptrace
|
||
quirks:
|
||
|
||
- If the thread group leader exits while other threads in the
|
||
thread group still exist, waitpid(TGID, ...) hangs. That
|
||
waitpid won't return an exit status until the other threads
|
||
in the group are reaped.
|
||
|
||
- When a non-leader thread execs, that thread just vanishes
|
||
without reporting an exit (so we'd hang if we waited for it
|
||
explicitly in that case). The exec event is reported to
|
||
the TGID pid. */
|
||
|
||
errno = 0;
|
||
lwpid = my_waitpid (-1, &status, __WALL | WNOHANG);
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNW: waitpid(-1, ...) returned %d, %s\n",
|
||
lwpid, errno ? safe_strerror (errno) : "ERRNO-OK");
|
||
|
||
if (lwpid > 0)
|
||
{
|
||
if (debug_linux_nat)
|
||
{
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: waitpid %ld received %s\n",
|
||
(long) lwpid, status_to_str (status));
|
||
}
|
||
|
||
linux_nat_filter_event (lwpid, status);
|
||
/* Retry until nothing comes out of waitpid. A single
|
||
SIGCHLD can indicate more than one child stopped. */
|
||
continue;
|
||
}
|
||
|
||
/* Now that we've pulled all events out of the kernel, resume
|
||
LWPs that don't have an interesting event to report. */
|
||
iterate_over_lwps (minus_one_ptid,
|
||
[] (struct lwp_info *info)
|
||
{
|
||
return resume_stopped_resumed_lwps (info, minus_one_ptid);
|
||
});
|
||
|
||
/* ... and find an LWP with a status to report to the core, if
|
||
any. */
|
||
lp = iterate_over_lwps (ptid, status_callback);
|
||
if (lp != NULL)
|
||
break;
|
||
|
||
/* Check for zombie thread group leaders. Those can't be reaped
|
||
until all other threads in the thread group are. */
|
||
check_zombie_leaders ();
|
||
|
||
/* If there are no resumed children left, bail. We'd be stuck
|
||
forever in the sigsuspend call below otherwise. */
|
||
if (iterate_over_lwps (ptid, resumed_callback) == NULL)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "LLW: exit (no resumed LWP)\n");
|
||
|
||
ourstatus->kind = TARGET_WAITKIND_NO_RESUMED;
|
||
|
||
restore_child_signals_mask (&prev_mask);
|
||
return minus_one_ptid;
|
||
}
|
||
|
||
/* No interesting event to report to the core. */
|
||
|
||
if (target_options & TARGET_WNOHANG)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "LLW: exit (ignore)\n");
|
||
|
||
ourstatus->kind = TARGET_WAITKIND_IGNORE;
|
||
restore_child_signals_mask (&prev_mask);
|
||
return minus_one_ptid;
|
||
}
|
||
|
||
/* We shouldn't end up here unless we want to try again. */
|
||
gdb_assert (lp == NULL);
|
||
|
||
/* Block until we get an event reported with SIGCHLD. */
|
||
wait_for_signal ();
|
||
}
|
||
|
||
gdb_assert (lp);
|
||
|
||
status = lp->status;
|
||
lp->status = 0;
|
||
|
||
if (!target_is_non_stop_p ())
|
||
{
|
||
/* Now stop all other LWP's ... */
|
||
iterate_over_lwps (minus_one_ptid, stop_callback);
|
||
|
||
/* ... and wait until all of them have reported back that
|
||
they're no longer running. */
|
||
iterate_over_lwps (minus_one_ptid, stop_wait_callback);
|
||
}
|
||
|
||
/* If we're not waiting for a specific LWP, choose an event LWP from
|
||
among those that have had events. Giving equal priority to all
|
||
LWPs that have had events helps prevent starvation. */
|
||
if (ptid == minus_one_ptid || ptid.is_pid ())
|
||
select_event_lwp (ptid, &lp, &status);
|
||
|
||
gdb_assert (lp != NULL);
|
||
|
||
/* Now that we've selected our final event LWP, un-adjust its PC if
|
||
it was a software breakpoint, and we can't reliably support the
|
||
"stopped by software breakpoint" stop reason. */
|
||
if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT
|
||
&& !USE_SIGTRAP_SIGINFO)
|
||
{
|
||
struct regcache *regcache = get_thread_regcache (lp->ptid);
|
||
struct gdbarch *gdbarch = regcache->arch ();
|
||
int decr_pc = gdbarch_decr_pc_after_break (gdbarch);
|
||
|
||
if (decr_pc != 0)
|
||
{
|
||
CORE_ADDR pc;
|
||
|
||
pc = regcache_read_pc (regcache);
|
||
regcache_write_pc (regcache, pc + decr_pc);
|
||
}
|
||
}
|
||
|
||
/* We'll need this to determine whether to report a SIGSTOP as
|
||
GDB_SIGNAL_0. Need to take a copy because resume_clear_callback
|
||
clears it. */
|
||
last_resume_kind = lp->last_resume_kind;
|
||
|
||
if (!target_is_non_stop_p ())
|
||
{
|
||
/* In all-stop, from the core's perspective, all LWPs are now
|
||
stopped until a new resume action is sent over. */
|
||
iterate_over_lwps (minus_one_ptid, resume_clear_callback);
|
||
}
|
||
else
|
||
{
|
||
resume_clear_callback (lp);
|
||
}
|
||
|
||
if (linux_target->low_status_is_event (status))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LLW: trap ptid is %s.\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
|
||
if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
|
||
{
|
||
*ourstatus = lp->waitstatus;
|
||
lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
|
||
}
|
||
else
|
||
store_waitstatus (ourstatus, status);
|
||
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog, "LLW: exit\n");
|
||
|
||
restore_child_signals_mask (&prev_mask);
|
||
|
||
if (last_resume_kind == resume_stop
|
||
&& ourstatus->kind == TARGET_WAITKIND_STOPPED
|
||
&& WSTOPSIG (status) == SIGSTOP)
|
||
{
|
||
/* A thread that has been requested to stop by GDB with
|
||
target_stop, and it stopped cleanly, so report as SIG0. The
|
||
use of SIGSTOP is an implementation detail. */
|
||
ourstatus->value.sig = GDB_SIGNAL_0;
|
||
}
|
||
|
||
if (ourstatus->kind == TARGET_WAITKIND_EXITED
|
||
|| ourstatus->kind == TARGET_WAITKIND_SIGNALLED)
|
||
lp->core = -1;
|
||
else
|
||
lp->core = linux_common_core_of_thread (lp->ptid);
|
||
|
||
if (ourstatus->kind == TARGET_WAITKIND_EXITED)
|
||
return filter_exit_event (lp, ourstatus);
|
||
|
||
return lp->ptid;
|
||
}
|
||
|
||
/* Resume LWPs that are currently stopped without any pending status
|
||
to report, but are resumed from the core's perspective. */
|
||
|
||
static int
|
||
resume_stopped_resumed_lwps (struct lwp_info *lp, const ptid_t wait_ptid)
|
||
{
|
||
if (!lp->stopped)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RSRL: NOT resuming LWP %s, not stopped\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
else if (!lp->resumed)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RSRL: NOT resuming LWP %s, not resumed\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
else if (lwp_status_pending_p (lp))
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RSRL: NOT resuming LWP %s, has pending status\n",
|
||
target_pid_to_str (lp->ptid).c_str ());
|
||
}
|
||
else
|
||
{
|
||
struct regcache *regcache = get_thread_regcache (lp->ptid);
|
||
struct gdbarch *gdbarch = regcache->arch ();
|
||
|
||
try
|
||
{
|
||
CORE_ADDR pc = regcache_read_pc (regcache);
|
||
int leave_stopped = 0;
|
||
|
||
/* Don't bother if there's a breakpoint at PC that we'd hit
|
||
immediately, and we're not waiting for this LWP. */
|
||
if (!lp->ptid.matches (wait_ptid))
|
||
{
|
||
if (breakpoint_inserted_here_p (regcache->aspace (), pc))
|
||
leave_stopped = 1;
|
||
}
|
||
|
||
if (!leave_stopped)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"RSRL: resuming stopped-resumed LWP %s at "
|
||
"%s: step=%d\n",
|
||
target_pid_to_str (lp->ptid).c_str (),
|
||
paddress (gdbarch, pc),
|
||
lp->step);
|
||
|
||
linux_resume_one_lwp_throw (lp, lp->step, GDB_SIGNAL_0);
|
||
}
|
||
}
|
||
catch (const gdb_exception_error &ex)
|
||
{
|
||
if (!check_ptrace_stopped_lwp_gone (lp))
|
||
throw;
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
ptid_t
|
||
linux_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
|
||
int target_options)
|
||
{
|
||
ptid_t event_ptid;
|
||
|
||
if (debug_linux_nat)
|
||
{
|
||
std::string options_string = target_options_to_string (target_options);
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"linux_nat_wait: [%s], [%s]\n",
|
||
target_pid_to_str (ptid).c_str (),
|
||
options_string.c_str ());
|
||
}
|
||
|
||
/* Flush the async file first. */
|
||
if (target_is_async_p ())
|
||
async_file_flush ();
|
||
|
||
/* Resume LWPs that are currently stopped without any pending status
|
||
to report, but are resumed from the core's perspective. LWPs get
|
||
in this state if we find them stopping at a time we're not
|
||
interested in reporting the event (target_wait on a
|
||
specific_process, for example, see linux_nat_wait_1), and
|
||
meanwhile the event became uninteresting. Don't bother resuming
|
||
LWPs we're not going to wait for if they'd stop immediately. */
|
||
if (target_is_non_stop_p ())
|
||
iterate_over_lwps (minus_one_ptid,
|
||
[=] (struct lwp_info *info)
|
||
{
|
||
return resume_stopped_resumed_lwps (info, ptid);
|
||
});
|
||
|
||
event_ptid = linux_nat_wait_1 (ptid, ourstatus, target_options);
|
||
|
||
/* If we requested any event, and something came out, assume there
|
||
may be more. If we requested a specific lwp or process, also
|
||
assume there may be more. */
|
||
if (target_is_async_p ()
|
||
&& ((ourstatus->kind != TARGET_WAITKIND_IGNORE
|
||
&& ourstatus->kind != TARGET_WAITKIND_NO_RESUMED)
|
||
|| ptid != minus_one_ptid))
|
||
async_file_mark ();
|
||
|
||
return event_ptid;
|
||
}
|
||
|
||
/* Kill one LWP. */
|
||
|
||
static void
|
||
kill_one_lwp (pid_t pid)
|
||
{
|
||
/* PTRACE_KILL may resume the inferior. Send SIGKILL first. */
|
||
|
||
errno = 0;
|
||
kill_lwp (pid, SIGKILL);
|
||
if (debug_linux_nat)
|
||
{
|
||
int save_errno = errno;
|
||
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"KC: kill (SIGKILL) %ld, 0, 0 (%s)\n", (long) pid,
|
||
save_errno ? safe_strerror (save_errno) : "OK");
|
||
}
|
||
|
||
/* Some kernels ignore even SIGKILL for processes under ptrace. */
|
||
|
||
errno = 0;
|
||
ptrace (PTRACE_KILL, pid, 0, 0);
|
||
if (debug_linux_nat)
|
||
{
|
||
int save_errno = errno;
|
||
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"KC: PTRACE_KILL %ld, 0, 0 (%s)\n", (long) pid,
|
||
save_errno ? safe_strerror (save_errno) : "OK");
|
||
}
|
||
}
|
||
|
||
/* Wait for an LWP to die. */
|
||
|
||
static void
|
||
kill_wait_one_lwp (pid_t pid)
|
||
{
|
||
pid_t res;
|
||
|
||
/* We must make sure that there are no pending events (delayed
|
||
SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
|
||
program doesn't interfere with any following debugging session. */
|
||
|
||
do
|
||
{
|
||
res = my_waitpid (pid, NULL, __WALL);
|
||
if (res != (pid_t) -1)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"KWC: wait %ld received unknown.\n",
|
||
(long) pid);
|
||
/* The Linux kernel sometimes fails to kill a thread
|
||
completely after PTRACE_KILL; that goes from the stop
|
||
point in do_fork out to the one in get_signal_to_deliver
|
||
and waits again. So kill it again. */
|
||
kill_one_lwp (pid);
|
||
}
|
||
}
|
||
while (res == pid);
|
||
|
||
gdb_assert (res == -1 && errno == ECHILD);
|
||
}
|
||
|
||
/* Callback for iterate_over_lwps. */
|
||
|
||
static int
|
||
kill_callback (struct lwp_info *lp)
|
||
{
|
||
kill_one_lwp (lp->ptid.lwp ());
|
||
return 0;
|
||
}
|
||
|
||
/* Callback for iterate_over_lwps. */
|
||
|
||
static int
|
||
kill_wait_callback (struct lwp_info *lp)
|
||
{
|
||
kill_wait_one_lwp (lp->ptid.lwp ());
|
||
return 0;
|
||
}
|
||
|
||
/* Kill the fork children of any threads of inferior INF that are
|
||
stopped at a fork event. */
|
||
|
||
static void
|
||
kill_unfollowed_fork_children (struct inferior *inf)
|
||
{
|
||
for (thread_info *thread : inf->non_exited_threads ())
|
||
{
|
||
struct target_waitstatus *ws = &thread->pending_follow;
|
||
|
||
if (ws->kind == TARGET_WAITKIND_FORKED
|
||
|| ws->kind == TARGET_WAITKIND_VFORKED)
|
||
{
|
||
ptid_t child_ptid = ws->value.related_pid;
|
||
int child_pid = child_ptid.pid ();
|
||
int child_lwp = child_ptid.lwp ();
|
||
|
||
kill_one_lwp (child_lwp);
|
||
kill_wait_one_lwp (child_lwp);
|
||
|
||
/* Let the arch-specific native code know this process is
|
||
gone. */
|
||
linux_target->low_forget_process (child_pid);
|
||
}
|
||
}
|
||
}
|
||
|
||
void
|
||
linux_nat_target::kill ()
|
||
{
|
||
/* If we're stopped while forking and we haven't followed yet,
|
||
kill the other task. We need to do this first because the
|
||
parent will be sleeping if this is a vfork. */
|
||
kill_unfollowed_fork_children (current_inferior ());
|
||
|
||
if (forks_exist_p ())
|
||
linux_fork_killall ();
|
||
else
|
||
{
|
||
ptid_t ptid = ptid_t (inferior_ptid.pid ());
|
||
|
||
/* Stop all threads before killing them, since ptrace requires
|
||
that the thread is stopped to successfully PTRACE_KILL. */
|
||
iterate_over_lwps (ptid, stop_callback);
|
||
/* ... and wait until all of them have reported back that
|
||
they're no longer running. */
|
||
iterate_over_lwps (ptid, stop_wait_callback);
|
||
|
||
/* Kill all LWP's ... */
|
||
iterate_over_lwps (ptid, kill_callback);
|
||
|
||
/* ... and wait until we've flushed all events. */
|
||
iterate_over_lwps (ptid, kill_wait_callback);
|
||
}
|
||
|
||
target_mourn_inferior (inferior_ptid);
|
||
}
|
||
|
||
void
|
||
linux_nat_target::mourn_inferior ()
|
||
{
|
||
int pid = inferior_ptid.pid ();
|
||
|
||
purge_lwp_list (pid);
|
||
|
||
if (! forks_exist_p ())
|
||
/* Normal case, no other forks available. */
|
||
inf_ptrace_target::mourn_inferior ();
|
||
else
|
||
/* Multi-fork case. The current inferior_ptid has exited, but
|
||
there are other viable forks to debug. Delete the exiting
|
||
one and context-switch to the first available. */
|
||
linux_fork_mourn_inferior ();
|
||
|
||
/* Let the arch-specific native code know this process is gone. */
|
||
linux_target->low_forget_process (pid);
|
||
}
|
||
|
||
/* Convert a native/host siginfo object, into/from the siginfo in the
|
||
layout of the inferiors' architecture. */
|
||
|
||
static void
|
||
siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction)
|
||
{
|
||
/* If the low target didn't do anything, then just do a straight
|
||
memcpy. */
|
||
if (!linux_target->low_siginfo_fixup (siginfo, inf_siginfo, direction))
|
||
{
|
||
if (direction == 1)
|
||
memcpy (siginfo, inf_siginfo, sizeof (siginfo_t));
|
||
else
|
||
memcpy (inf_siginfo, siginfo, sizeof (siginfo_t));
|
||
}
|
||
}
|
||
|
||
static enum target_xfer_status
|
||
linux_xfer_siginfo (enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
|
||
ULONGEST *xfered_len)
|
||
{
|
||
int pid;
|
||
siginfo_t siginfo;
|
||
gdb_byte inf_siginfo[sizeof (siginfo_t)];
|
||
|
||
gdb_assert (object == TARGET_OBJECT_SIGNAL_INFO);
|
||
gdb_assert (readbuf || writebuf);
|
||
|
||
pid = inferior_ptid.lwp ();
|
||
if (pid == 0)
|
||
pid = inferior_ptid.pid ();
|
||
|
||
if (offset > sizeof (siginfo))
|
||
return TARGET_XFER_E_IO;
|
||
|
||
errno = 0;
|
||
ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
|
||
if (errno != 0)
|
||
return TARGET_XFER_E_IO;
|
||
|
||
/* When GDB is built as a 64-bit application, ptrace writes into
|
||
SIGINFO an object with 64-bit layout. Since debugging a 32-bit
|
||
inferior with a 64-bit GDB should look the same as debugging it
|
||
with a 32-bit GDB, we need to convert it. GDB core always sees
|
||
the converted layout, so any read/write will have to be done
|
||
post-conversion. */
|
||
siginfo_fixup (&siginfo, inf_siginfo, 0);
|
||
|
||
if (offset + len > sizeof (siginfo))
|
||
len = sizeof (siginfo) - offset;
|
||
|
||
if (readbuf != NULL)
|
||
memcpy (readbuf, inf_siginfo + offset, len);
|
||
else
|
||
{
|
||
memcpy (inf_siginfo + offset, writebuf, len);
|
||
|
||
/* Convert back to ptrace layout before flushing it out. */
|
||
siginfo_fixup (&siginfo, inf_siginfo, 1);
|
||
|
||
errno = 0;
|
||
ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo);
|
||
if (errno != 0)
|
||
return TARGET_XFER_E_IO;
|
||
}
|
||
|
||
*xfered_len = len;
|
||
return TARGET_XFER_OK;
|
||
}
|
||
|
||
static enum target_xfer_status
|
||
linux_nat_xfer_osdata (enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
|
||
ULONGEST *xfered_len);
|
||
|
||
static enum target_xfer_status
|
||
linux_proc_xfer_partial (enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf,
|
||
ULONGEST offset, LONGEST len, ULONGEST *xfered_len);
|
||
|
||
enum target_xfer_status
|
||
linux_nat_target::xfer_partial (enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf,
|
||
ULONGEST offset, ULONGEST len, ULONGEST *xfered_len)
|
||
{
|
||
enum target_xfer_status xfer;
|
||
|
||
if (object == TARGET_OBJECT_SIGNAL_INFO)
|
||
return linux_xfer_siginfo (object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
|
||
/* The target is connected but no live inferior is selected. Pass
|
||
this request down to a lower stratum (e.g., the executable
|
||
file). */
|
||
if (object == TARGET_OBJECT_MEMORY && inferior_ptid == null_ptid)
|
||
return TARGET_XFER_EOF;
|
||
|
||
if (object == TARGET_OBJECT_AUXV)
|
||
return memory_xfer_auxv (this, object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
|
||
if (object == TARGET_OBJECT_OSDATA)
|
||
return linux_nat_xfer_osdata (object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
|
||
/* GDB calculates all addresses in the largest possible address
|
||
width.
|
||
The address width must be masked before its final use - either by
|
||
linux_proc_xfer_partial or inf_ptrace_target::xfer_partial.
|
||
|
||
Compare ADDR_BIT first to avoid a compiler warning on shift overflow. */
|
||
|
||
if (object == TARGET_OBJECT_MEMORY)
|
||
{
|
||
int addr_bit = gdbarch_addr_bit (target_gdbarch ());
|
||
|
||
if (addr_bit < (sizeof (ULONGEST) * HOST_CHAR_BIT))
|
||
offset &= ((ULONGEST) 1 << addr_bit) - 1;
|
||
}
|
||
|
||
xfer = linux_proc_xfer_partial (object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
if (xfer != TARGET_XFER_EOF)
|
||
return xfer;
|
||
|
||
return inf_ptrace_target::xfer_partial (object, annex, readbuf, writebuf,
|
||
offset, len, xfered_len);
|
||
}
|
||
|
||
bool
|
||
linux_nat_target::thread_alive (ptid_t ptid)
|
||
{
|
||
/* As long as a PTID is in lwp list, consider it alive. */
|
||
return find_lwp_pid (ptid) != NULL;
|
||
}
|
||
|
||
/* Implement the to_update_thread_list target method for this
|
||
target. */
|
||
|
||
void
|
||
linux_nat_target::update_thread_list ()
|
||
{
|
||
struct lwp_info *lwp;
|
||
|
||
/* We add/delete threads from the list as clone/exit events are
|
||
processed, so just try deleting exited threads still in the
|
||
thread list. */
|
||
delete_exited_threads ();
|
||
|
||
/* Update the processor core that each lwp/thread was last seen
|
||
running on. */
|
||
ALL_LWPS (lwp)
|
||
{
|
||
/* Avoid accessing /proc if the thread hasn't run since we last
|
||
time we fetched the thread's core. Accessing /proc becomes
|
||
noticeably expensive when we have thousands of LWPs. */
|
||
if (lwp->core == -1)
|
||
lwp->core = linux_common_core_of_thread (lwp->ptid);
|
||
}
|
||
}
|
||
|
||
std::string
|
||
linux_nat_target::pid_to_str (ptid_t ptid)
|
||
{
|
||
if (ptid.lwp_p ()
|
||
&& (ptid.pid () != ptid.lwp ()
|
||
|| num_lwps (ptid.pid ()) > 1))
|
||
return string_printf ("LWP %ld", ptid.lwp ());
|
||
|
||
return normal_pid_to_str (ptid);
|
||
}
|
||
|
||
const char *
|
||
linux_nat_target::thread_name (struct thread_info *thr)
|
||
{
|
||
return linux_proc_tid_get_name (thr->ptid);
|
||
}
|
||
|
||
/* Accepts an integer PID; Returns a string representing a file that
|
||
can be opened to get the symbols for the child process. */
|
||
|
||
char *
|
||
linux_nat_target::pid_to_exec_file (int pid)
|
||
{
|
||
return linux_proc_pid_to_exec_file (pid);
|
||
}
|
||
|
||
/* Implement the to_xfer_partial target method using /proc/<pid>/mem.
|
||
Because we can use a single read/write call, this can be much more
|
||
efficient than banging away at PTRACE_PEEKTEXT. */
|
||
|
||
static enum target_xfer_status
|
||
linux_proc_xfer_partial (enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf,
|
||
ULONGEST offset, LONGEST len, ULONGEST *xfered_len)
|
||
{
|
||
LONGEST ret;
|
||
int fd;
|
||
char filename[64];
|
||
|
||
if (object != TARGET_OBJECT_MEMORY)
|
||
return TARGET_XFER_EOF;
|
||
|
||
/* Don't bother for one word. */
|
||
if (len < 3 * sizeof (long))
|
||
return TARGET_XFER_EOF;
|
||
|
||
/* We could keep this file open and cache it - possibly one per
|
||
thread. That requires some juggling, but is even faster. */
|
||
xsnprintf (filename, sizeof filename, "/proc/%ld/mem",
|
||
inferior_ptid.lwp ());
|
||
fd = gdb_open_cloexec (filename, ((readbuf ? O_RDONLY : O_WRONLY)
|
||
| O_LARGEFILE), 0);
|
||
if (fd == -1)
|
||
return TARGET_XFER_EOF;
|
||
|
||
/* Use pread64/pwrite64 if available, since they save a syscall and can
|
||
handle 64-bit offsets even on 32-bit platforms (for instance, SPARC
|
||
debugging a SPARC64 application). */
|
||
#ifdef HAVE_PREAD64
|
||
ret = (readbuf ? pread64 (fd, readbuf, len, offset)
|
||
: pwrite64 (fd, writebuf, len, offset));
|
||
#else
|
||
ret = lseek (fd, offset, SEEK_SET);
|
||
if (ret != -1)
|
||
ret = (readbuf ? read (fd, readbuf, len)
|
||
: write (fd, writebuf, len));
|
||
#endif
|
||
|
||
close (fd);
|
||
|
||
if (ret == -1 || ret == 0)
|
||
return TARGET_XFER_EOF;
|
||
else
|
||
{
|
||
*xfered_len = ret;
|
||
return TARGET_XFER_OK;
|
||
}
|
||
}
|
||
|
||
|
||
/* Parse LINE as a signal set and add its set bits to SIGS. */
|
||
|
||
static void
|
||
add_line_to_sigset (const char *line, sigset_t *sigs)
|
||
{
|
||
int len = strlen (line) - 1;
|
||
const char *p;
|
||
int signum;
|
||
|
||
if (line[len] != '\n')
|
||
error (_("Could not parse signal set: %s"), line);
|
||
|
||
p = line;
|
||
signum = len * 4;
|
||
while (len-- > 0)
|
||
{
|
||
int digit;
|
||
|
||
if (*p >= '0' && *p <= '9')
|
||
digit = *p - '0';
|
||
else if (*p >= 'a' && *p <= 'f')
|
||
digit = *p - 'a' + 10;
|
||
else
|
||
error (_("Could not parse signal set: %s"), line);
|
||
|
||
signum -= 4;
|
||
|
||
if (digit & 1)
|
||
sigaddset (sigs, signum + 1);
|
||
if (digit & 2)
|
||
sigaddset (sigs, signum + 2);
|
||
if (digit & 4)
|
||
sigaddset (sigs, signum + 3);
|
||
if (digit & 8)
|
||
sigaddset (sigs, signum + 4);
|
||
|
||
p++;
|
||
}
|
||
}
|
||
|
||
/* Find process PID's pending signals from /proc/pid/status and set
|
||
SIGS to match. */
|
||
|
||
void
|
||
linux_proc_pending_signals (int pid, sigset_t *pending,
|
||
sigset_t *blocked, sigset_t *ignored)
|
||
{
|
||
char buffer[PATH_MAX], fname[PATH_MAX];
|
||
|
||
sigemptyset (pending);
|
||
sigemptyset (blocked);
|
||
sigemptyset (ignored);
|
||
xsnprintf (fname, sizeof fname, "/proc/%d/status", pid);
|
||
gdb_file_up procfile = gdb_fopen_cloexec (fname, "r");
|
||
if (procfile == NULL)
|
||
error (_("Could not open %s"), fname);
|
||
|
||
while (fgets (buffer, PATH_MAX, procfile.get ()) != NULL)
|
||
{
|
||
/* Normal queued signals are on the SigPnd line in the status
|
||
file. However, 2.6 kernels also have a "shared" pending
|
||
queue for delivering signals to a thread group, so check for
|
||
a ShdPnd line also.
|
||
|
||
Unfortunately some Red Hat kernels include the shared pending
|
||
queue but not the ShdPnd status field. */
|
||
|
||
if (startswith (buffer, "SigPnd:\t"))
|
||
add_line_to_sigset (buffer + 8, pending);
|
||
else if (startswith (buffer, "ShdPnd:\t"))
|
||
add_line_to_sigset (buffer + 8, pending);
|
||
else if (startswith (buffer, "SigBlk:\t"))
|
||
add_line_to_sigset (buffer + 8, blocked);
|
||
else if (startswith (buffer, "SigIgn:\t"))
|
||
add_line_to_sigset (buffer + 8, ignored);
|
||
}
|
||
}
|
||
|
||
static enum target_xfer_status
|
||
linux_nat_xfer_osdata (enum target_object object,
|
||
const char *annex, gdb_byte *readbuf,
|
||
const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
|
||
ULONGEST *xfered_len)
|
||
{
|
||
gdb_assert (object == TARGET_OBJECT_OSDATA);
|
||
|
||
*xfered_len = linux_common_xfer_osdata (annex, readbuf, offset, len);
|
||
if (*xfered_len == 0)
|
||
return TARGET_XFER_EOF;
|
||
else
|
||
return TARGET_XFER_OK;
|
||
}
|
||
|
||
std::vector<static_tracepoint_marker>
|
||
linux_nat_target::static_tracepoint_markers_by_strid (const char *strid)
|
||
{
|
||
char s[IPA_CMD_BUF_SIZE];
|
||
int pid = inferior_ptid.pid ();
|
||
std::vector<static_tracepoint_marker> markers;
|
||
const char *p = s;
|
||
ptid_t ptid = ptid_t (pid, 0, 0);
|
||
static_tracepoint_marker marker;
|
||
|
||
/* Pause all */
|
||
target_stop (ptid);
|
||
|
||
memcpy (s, "qTfSTM", sizeof ("qTfSTM"));
|
||
s[sizeof ("qTfSTM")] = 0;
|
||
|
||
agent_run_command (pid, s, strlen (s) + 1);
|
||
|
||
/* Unpause all. */
|
||
SCOPE_EXIT { target_continue_no_signal (ptid); };
|
||
|
||
while (*p++ == 'm')
|
||
{
|
||
do
|
||
{
|
||
parse_static_tracepoint_marker_definition (p, &p, &marker);
|
||
|
||
if (strid == NULL || marker.str_id == strid)
|
||
markers.push_back (std::move (marker));
|
||
}
|
||
while (*p++ == ','); /* comma-separated list */
|
||
|
||
memcpy (s, "qTsSTM", sizeof ("qTsSTM"));
|
||
s[sizeof ("qTsSTM")] = 0;
|
||
agent_run_command (pid, s, strlen (s) + 1);
|
||
p = s;
|
||
}
|
||
|
||
return markers;
|
||
}
|
||
|
||
/* target_is_async_p implementation. */
|
||
|
||
bool
|
||
linux_nat_target::is_async_p ()
|
||
{
|
||
return linux_is_async_p ();
|
||
}
|
||
|
||
/* target_can_async_p implementation. */
|
||
|
||
bool
|
||
linux_nat_target::can_async_p ()
|
||
{
|
||
/* We're always async, unless the user explicitly prevented it with the
|
||
"maint set target-async" command. */
|
||
return target_async_permitted;
|
||
}
|
||
|
||
bool
|
||
linux_nat_target::supports_non_stop ()
|
||
{
|
||
return 1;
|
||
}
|
||
|
||
/* to_always_non_stop_p implementation. */
|
||
|
||
bool
|
||
linux_nat_target::always_non_stop_p ()
|
||
{
|
||
return 1;
|
||
}
|
||
|
||
/* True if we want to support multi-process. To be removed when GDB
|
||
supports multi-exec. */
|
||
|
||
int linux_multi_process = 1;
|
||
|
||
bool
|
||
linux_nat_target::supports_multi_process ()
|
||
{
|
||
return linux_multi_process;
|
||
}
|
||
|
||
bool
|
||
linux_nat_target::supports_disable_randomization ()
|
||
{
|
||
#ifdef HAVE_PERSONALITY
|
||
return 1;
|
||
#else
|
||
return 0;
|
||
#endif
|
||
}
|
||
|
||
/* SIGCHLD handler that serves two purposes: In non-stop/async mode,
|
||
so we notice when any child changes state, and notify the
|
||
event-loop; it allows us to use sigsuspend in linux_nat_wait_1
|
||
above to wait for the arrival of a SIGCHLD. */
|
||
|
||
static void
|
||
sigchld_handler (int signo)
|
||
{
|
||
int old_errno = errno;
|
||
|
||
if (debug_linux_nat)
|
||
ui_file_write_async_safe (gdb_stdlog,
|
||
"sigchld\n", sizeof ("sigchld\n") - 1);
|
||
|
||
if (signo == SIGCHLD
|
||
&& linux_nat_event_pipe[0] != -1)
|
||
async_file_mark (); /* Let the event loop know that there are
|
||
events to handle. */
|
||
|
||
errno = old_errno;
|
||
}
|
||
|
||
/* Callback registered with the target events file descriptor. */
|
||
|
||
static void
|
||
handle_target_event (int error, gdb_client_data client_data)
|
||
{
|
||
inferior_event_handler (INF_REG_EVENT, NULL);
|
||
}
|
||
|
||
/* Create/destroy the target events pipe. Returns previous state. */
|
||
|
||
static int
|
||
linux_async_pipe (int enable)
|
||
{
|
||
int previous = linux_is_async_p ();
|
||
|
||
if (previous != enable)
|
||
{
|
||
sigset_t prev_mask;
|
||
|
||
/* Block child signals while we create/destroy the pipe, as
|
||
their handler writes to it. */
|
||
block_child_signals (&prev_mask);
|
||
|
||
if (enable)
|
||
{
|
||
if (gdb_pipe_cloexec (linux_nat_event_pipe) == -1)
|
||
internal_error (__FILE__, __LINE__,
|
||
"creating event pipe failed.");
|
||
|
||
fcntl (linux_nat_event_pipe[0], F_SETFL, O_NONBLOCK);
|
||
fcntl (linux_nat_event_pipe[1], F_SETFL, O_NONBLOCK);
|
||
}
|
||
else
|
||
{
|
||
close (linux_nat_event_pipe[0]);
|
||
close (linux_nat_event_pipe[1]);
|
||
linux_nat_event_pipe[0] = -1;
|
||
linux_nat_event_pipe[1] = -1;
|
||
}
|
||
|
||
restore_child_signals_mask (&prev_mask);
|
||
}
|
||
|
||
return previous;
|
||
}
|
||
|
||
/* target_async implementation. */
|
||
|
||
void
|
||
linux_nat_target::async (int enable)
|
||
{
|
||
if (enable)
|
||
{
|
||
if (!linux_async_pipe (1))
|
||
{
|
||
add_file_handler (linux_nat_event_pipe[0],
|
||
handle_target_event, NULL);
|
||
/* There may be pending events to handle. Tell the event loop
|
||
to poll them. */
|
||
async_file_mark ();
|
||
}
|
||
}
|
||
else
|
||
{
|
||
delete_file_handler (linux_nat_event_pipe[0]);
|
||
linux_async_pipe (0);
|
||
}
|
||
return;
|
||
}
|
||
|
||
/* Stop an LWP, and push a GDB_SIGNAL_0 stop status if no other
|
||
event came out. */
|
||
|
||
static int
|
||
linux_nat_stop_lwp (struct lwp_info *lwp)
|
||
{
|
||
if (!lwp->stopped)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNSL: running -> suspending %s\n",
|
||
target_pid_to_str (lwp->ptid).c_str ());
|
||
|
||
|
||
if (lwp->last_resume_kind == resume_stop)
|
||
{
|
||
if (debug_linux_nat)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"linux-nat: already stopping LWP %ld at "
|
||
"GDB's request\n",
|
||
lwp->ptid.lwp ());
|
||
return 0;
|
||
}
|
||
|
||
stop_callback (lwp);
|
||
lwp->last_resume_kind = resume_stop;
|
||
}
|
||
else
|
||
{
|
||
/* Already known to be stopped; do nothing. */
|
||
|
||
if (debug_linux_nat)
|
||
{
|
||
if (find_thread_ptid (lwp->ptid)->stop_requested)
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNSL: already stopped/stop_requested %s\n",
|
||
target_pid_to_str (lwp->ptid).c_str ());
|
||
else
|
||
fprintf_unfiltered (gdb_stdlog,
|
||
"LNSL: already stopped/no "
|
||
"stop_requested yet %s\n",
|
||
target_pid_to_str (lwp->ptid).c_str ());
|
||
}
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
void
|
||
linux_nat_target::stop (ptid_t ptid)
|
||
{
|
||
iterate_over_lwps (ptid, linux_nat_stop_lwp);
|
||
}
|
||
|
||
void
|
||
linux_nat_target::close ()
|
||
{
|
||
/* Unregister from the event loop. */
|
||
if (is_async_p ())
|
||
async (0);
|
||
|
||
inf_ptrace_target::close ();
|
||
}
|
||
|
||
/* When requests are passed down from the linux-nat layer to the
|
||
single threaded inf-ptrace layer, ptids of (lwpid,0,0) form are
|
||
used. The address space pointer is stored in the inferior object,
|
||
but the common code that is passed such ptid can't tell whether
|
||
lwpid is a "main" process id or not (it assumes so). We reverse
|
||
look up the "main" process id from the lwp here. */
|
||
|
||
struct address_space *
|
||
linux_nat_target::thread_address_space (ptid_t ptid)
|
||
{
|
||
struct lwp_info *lwp;
|
||
struct inferior *inf;
|
||
int pid;
|
||
|
||
if (ptid.lwp () == 0)
|
||
{
|
||
/* An (lwpid,0,0) ptid. Look up the lwp object to get at the
|
||
tgid. */
|
||
lwp = find_lwp_pid (ptid);
|
||
pid = lwp->ptid.pid ();
|
||
}
|
||
else
|
||
{
|
||
/* A (pid,lwpid,0) ptid. */
|
||
pid = ptid.pid ();
|
||
}
|
||
|
||
inf = find_inferior_pid (pid);
|
||
gdb_assert (inf != NULL);
|
||
return inf->aspace;
|
||
}
|
||
|
||
/* Return the cached value of the processor core for thread PTID. */
|
||
|
||
int
|
||
linux_nat_target::core_of_thread (ptid_t ptid)
|
||
{
|
||
struct lwp_info *info = find_lwp_pid (ptid);
|
||
|
||
if (info)
|
||
return info->core;
|
||
return -1;
|
||
}
|
||
|
||
/* Implementation of to_filesystem_is_local. */
|
||
|
||
bool
|
||
linux_nat_target::filesystem_is_local ()
|
||
{
|
||
struct inferior *inf = current_inferior ();
|
||
|
||
if (inf->fake_pid_p || inf->pid == 0)
|
||
return true;
|
||
|
||
return linux_ns_same (inf->pid, LINUX_NS_MNT);
|
||
}
|
||
|
||
/* Convert the INF argument passed to a to_fileio_* method
|
||
to a process ID suitable for passing to its corresponding
|
||
linux_mntns_* function. If INF is non-NULL then the
|
||
caller is requesting the filesystem seen by INF. If INF
|
||
is NULL then the caller is requesting the filesystem seen
|
||
by the GDB. We fall back to GDB's filesystem in the case
|
||
that INF is non-NULL but its PID is unknown. */
|
||
|
||
static pid_t
|
||
linux_nat_fileio_pid_of (struct inferior *inf)
|
||
{
|
||
if (inf == NULL || inf->fake_pid_p || inf->pid == 0)
|
||
return getpid ();
|
||
else
|
||
return inf->pid;
|
||
}
|
||
|
||
/* Implementation of to_fileio_open. */
|
||
|
||
int
|
||
linux_nat_target::fileio_open (struct inferior *inf, const char *filename,
|
||
int flags, int mode, int warn_if_slow,
|
||
int *target_errno)
|
||
{
|
||
int nat_flags;
|
||
mode_t nat_mode;
|
||
int fd;
|
||
|
||
if (fileio_to_host_openflags (flags, &nat_flags) == -1
|
||
|| fileio_to_host_mode (mode, &nat_mode) == -1)
|
||
{
|
||
*target_errno = FILEIO_EINVAL;
|
||
return -1;
|
||
}
|
||
|
||
fd = linux_mntns_open_cloexec (linux_nat_fileio_pid_of (inf),
|
||
filename, nat_flags, nat_mode);
|
||
if (fd == -1)
|
||
*target_errno = host_to_fileio_error (errno);
|
||
|
||
return fd;
|
||
}
|
||
|
||
/* Implementation of to_fileio_readlink. */
|
||
|
||
gdb::optional<std::string>
|
||
linux_nat_target::fileio_readlink (struct inferior *inf, const char *filename,
|
||
int *target_errno)
|
||
{
|
||
char buf[PATH_MAX];
|
||
int len;
|
||
|
||
len = linux_mntns_readlink (linux_nat_fileio_pid_of (inf),
|
||
filename, buf, sizeof (buf));
|
||
if (len < 0)
|
||
{
|
||
*target_errno = host_to_fileio_error (errno);
|
||
return {};
|
||
}
|
||
|
||
return std::string (buf, len);
|
||
}
|
||
|
||
/* Implementation of to_fileio_unlink. */
|
||
|
||
int
|
||
linux_nat_target::fileio_unlink (struct inferior *inf, const char *filename,
|
||
int *target_errno)
|
||
{
|
||
int ret;
|
||
|
||
ret = linux_mntns_unlink (linux_nat_fileio_pid_of (inf),
|
||
filename);
|
||
if (ret == -1)
|
||
*target_errno = host_to_fileio_error (errno);
|
||
|
||
return ret;
|
||
}
|
||
|
||
/* Implementation of the to_thread_events method. */
|
||
|
||
void
|
||
linux_nat_target::thread_events (int enable)
|
||
{
|
||
report_thread_events = enable;
|
||
}
|
||
|
||
linux_nat_target::linux_nat_target ()
|
||
{
|
||
/* We don't change the stratum; this target will sit at
|
||
process_stratum and thread_db will set at thread_stratum. This
|
||
is a little strange, since this is a multi-threaded-capable
|
||
target, but we want to be on the stack below thread_db, and we
|
||
also want to be used for single-threaded processes. */
|
||
}
|
||
|
||
/* See linux-nat.h. */
|
||
|
||
int
|
||
linux_nat_get_siginfo (ptid_t ptid, siginfo_t *siginfo)
|
||
{
|
||
int pid;
|
||
|
||
pid = ptid.lwp ();
|
||
if (pid == 0)
|
||
pid = ptid.pid ();
|
||
|
||
errno = 0;
|
||
ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, siginfo);
|
||
if (errno != 0)
|
||
{
|
||
memset (siginfo, 0, sizeof (*siginfo));
|
||
return 0;
|
||
}
|
||
return 1;
|
||
}
|
||
|
||
/* See nat/linux-nat.h. */
|
||
|
||
ptid_t
|
||
current_lwp_ptid (void)
|
||
{
|
||
gdb_assert (inferior_ptid.lwp_p ());
|
||
return inferior_ptid;
|
||
}
|
||
|
||
void
|
||
_initialize_linux_nat (void)
|
||
{
|
||
add_setshow_zuinteger_cmd ("lin-lwp", class_maintenance,
|
||
&debug_linux_nat, _("\
|
||
Set debugging of GNU/Linux lwp module."), _("\
|
||
Show debugging of GNU/Linux lwp module."), _("\
|
||
Enables printf debugging output."),
|
||
NULL,
|
||
show_debug_linux_nat,
|
||
&setdebuglist, &showdebuglist);
|
||
|
||
add_setshow_boolean_cmd ("linux-namespaces", class_maintenance,
|
||
&debug_linux_namespaces, _("\
|
||
Set debugging of GNU/Linux namespaces module."), _("\
|
||
Show debugging of GNU/Linux namespaces module."), _("\
|
||
Enables printf debugging output."),
|
||
NULL,
|
||
NULL,
|
||
&setdebuglist, &showdebuglist);
|
||
|
||
/* Install a SIGCHLD handler. */
|
||
sigchld_action.sa_handler = sigchld_handler;
|
||
sigemptyset (&sigchld_action.sa_mask);
|
||
sigchld_action.sa_flags = SA_RESTART;
|
||
|
||
/* Make it the default. */
|
||
sigaction (SIGCHLD, &sigchld_action, NULL);
|
||
|
||
/* Make sure we don't block SIGCHLD during a sigsuspend. */
|
||
gdb_sigmask (SIG_SETMASK, NULL, &suspend_mask);
|
||
sigdelset (&suspend_mask, SIGCHLD);
|
||
|
||
sigemptyset (&blocked_mask);
|
||
|
||
lwp_lwpid_htab_create ();
|
||
}
|
||
|
||
|
||
/* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
|
||
the GNU/Linux Threads library and therefore doesn't really belong
|
||
here. */
|
||
|
||
/* Return the set of signals used by the threads library in *SET. */
|
||
|
||
void
|
||
lin_thread_get_thread_signals (sigset_t *set)
|
||
{
|
||
sigemptyset (set);
|
||
|
||
/* NPTL reserves the first two RT signals, but does not provide any
|
||
way for the debugger to query the signal numbers - fortunately
|
||
they don't change. */
|
||
sigaddset (set, __SIGRTMIN);
|
||
sigaddset (set, __SIGRTMIN + 1);
|
||
}
|