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/*
* dhcpcd - DHCP client daemon
* Copyright (c) 2006-2009 Roy Marples <roy@marples.name>
* All rights reserved
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "common.h"
#include "signals.h"
static int signal_pipe[2];
static const int handle_sigs[] = {
SIGALRM,
SIGHUP,
SIGINT,
SIGPIPE,
SIGTERM,
SIGUSR1,
};
static void
signal_handler(int sig)
{
int serrno = errno;
if (write(signal_pipe[1], &sig, sizeof(sig)) != sizeof(sig))
syslog(LOG_ERR, "failed to write signal %d: %m", sig);
/* Restore errno */
errno = serrno;
}
/* Read a signal from the signal pipe. Returns 0 if there is
* no signal, -1 on error (and sets errno appropriately), and
* your signal on success */
int
signal_read(void)
{
int sig = -1;
char buf[16];
ssize_t bytes;
memset(buf, 0, sizeof(buf));
bytes = read(signal_pipe[0], buf, sizeof(buf));
if (bytes >= 0 && (size_t)bytes >= sizeof(sig))
memcpy(&sig, buf, sizeof(sig));
return sig;
}
/* Call this before doing anything else. Sets up the socket pair
* and installs the signal handler */
int
signal_init(void)
{
if (pipe(signal_pipe) == -1)
return -1;
/* Don't block on read */
if (set_nonblock(signal_pipe[0]) == -1)
return -1;
/* Stop any scripts from inheriting us */
if (set_cloexec(signal_pipe[0]) == -1)
return -1;
if (set_cloexec(signal_pipe[1]) == -1)
return -1;
return signal_pipe[0];
}
static int
signal_handle(void (*func)(int))
{
unsigned int i;
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = func;
sigemptyset(&sa.sa_mask);
for (i = 0; i < sizeof(handle_sigs) / sizeof(handle_sigs[0]); i++)
if (sigaction(handle_sigs[i], &sa, NULL) == -1)
return -1;
return 0;
}
int
signal_setup(void)
{
return signal_handle(signal_handler);
}
int
signal_reset(void)
{
return signal_handle(SIG_DFL);
}
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