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/* Wrapper implementation for waitpid for GNU/Linux (LWP layer).
Copyright (C) 2001-2015 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "common-defs.h"
#ifdef GDBSERVER
/* FIXME: server.h is required for the definition of debug_threads
which is used in the gdbserver-specific debug printing in
linux_debug. This code should be made available to GDB also,
but the lack of a suitable flag to enable it prevents this. */
#include "server.h"
#endif
#include "linux-nat.h"
#include "linux-waitpid.h"
#include "gdb_wait.h"
/* Print debugging output based on the format string FORMAT and
its parameters. */
static inline void
linux_debug (const char *format, ...)
{
#ifdef GDBSERVER
if (debug_threads)
{
va_list args;
va_start (args, format);
vfprintf (stderr, format, args);
va_end (args);
}
#endif
}
/* Convert wait status STATUS to a string. Used for printing debug
messages only. */
char *
status_to_str (int status)
{
static char buf[64];
if (WIFSTOPPED (status))
{
if (WSTOPSIG (status) == SYSCALL_SIGTRAP)
snprintf (buf, sizeof (buf), "%s (stopped at syscall)",
strsignal (SIGTRAP));
else
snprintf (buf, sizeof (buf), "%s (stopped)",
strsignal (WSTOPSIG (status)));
}
else if (WIFSIGNALED (status))
snprintf (buf, sizeof (buf), "%s (terminated)",
strsignal (WTERMSIG (status)));
else
snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status));
return buf;
}
/* Wrapper function for waitpid which handles EINTR, and emulates
__WALL for systems where that is not available. */
int
my_waitpid (int pid, int *status, int flags)
{
int ret, out_errno;
linux_debug ("my_waitpid (%d, 0x%x)\n", pid, flags);
if (flags & __WALL)
{
sigset_t block_mask, org_mask, wake_mask;
int wnohang;
wnohang = (flags & WNOHANG) != 0;
flags &= ~(__WALL | __WCLONE);
if (!wnohang)
{
flags |= WNOHANG;
/* Block all signals while here. This avoids knowing about
LinuxThread's signals. */
sigfillset (&block_mask);
sigprocmask (SIG_BLOCK, &block_mask, &org_mask);
/* ... except during the sigsuspend below. */
sigemptyset (&wake_mask);
}
while (1)
{
/* Since all signals are blocked, there's no need to check
for EINTR here. */
ret = waitpid (pid, status, flags);
out_errno = errno;
if (ret == -1 && out_errno != ECHILD)
break;
else if (ret > 0)
break;
if (flags & __WCLONE)
{
/* We've tried both flavors now. If WNOHANG is set,
there's nothing else to do, just bail out. */
if (wnohang)
break;
linux_debug ("blocking\n");
/* Block waiting for signals. */
sigsuspend (&wake_mask);
}
flags ^= __WCLONE;
}
if (!wnohang)
sigprocmask (SIG_SETMASK, &org_mask, NULL);
}
else
{
do
ret = waitpid (pid, status, flags);
while (ret == -1 && errno == EINTR);
out_errno = errno;
}
linux_debug ("my_waitpid (%d, 0x%x): status(%x), %d\n",
pid, flags, (ret > 0 && status != NULL) ? *status : -1, ret);
errno = out_errno;
return ret;
}
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