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/* Wrapper implementation for waitpid for GNU/Linux (LWP layer).
Copyright (C) 2001-2014 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/>. */
#ifdef GDBSERVER
#include "server.h"
#else
#include "defs.h"
#include "signal.h"
#endif
#include "nat/linux-nat.h"
#include "nat/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);
}
#else
/* GDB-specific debugging output. */
#endif
}
/* 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);
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;
}
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, status ? *status : -1, ret);
errno = out_errno;
return ret;
}
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