/*
* dhcpcd - DHCP client daemon
* Copyright 2006-2008 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 <poll.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include "common.h"
#include "logger.h"
#include "signal.h"
static int signal_pipe[2];
static int signals[5];
static const int handle_sigs[] = {
SIGHUP,
SIGALRM,
SIGTERM,
SIGINT
};
static void signal_handler (int sig)
{
unsigned int i = 0;
int serrno = errno;
/* Add a signal to our stack */
while (signals[i])
i++;
if (i > sizeof (signals) / sizeof (signals[0]))
logger (LOG_ERR, "signal buffer overrun");
else
signals[i] = sig;
if (write (signal_pipe[1], &sig, sizeof (sig)) == -1)
logger (LOG_ERR, "Could not send signal: %s", strerror (errno));
/* Restore errno */
errno = serrno;
}
int signal_fd (void)
{
return (signal_pipe[0]);
}
/* Check if we have a signal or not */
int signal_exists (const struct pollfd *fd)
{
if (signals[0] || (fd && fd->revents & POLLIN))
return (0);
return (-1);
}
/* 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 (struct pollfd *fd)
{
int sig = -1;
/* Pop a signal off the our stack */
if (signals[0]) {
unsigned int i = 0;
sig = signals[0];
while (i < (sizeof (signals) / sizeof (signals[0])) - 1) {
signals[i] = signals[i + 1];
if (! signals[++i])
break;
}
}
if (fd && fd->revents & POLLIN) {
char buf[16];
size_t bytes;
memset (buf, 0, sizeof (buf));
bytes = read (signal_pipe[0], buf, sizeof (buf));
if (bytes >= sizeof (sig))
memcpy (&sig, buf, sizeof (sig));
/* We need to clear us from rset if nothing left in the buffer
* in case we are called many times */
if (bytes == sizeof (sig))
fd->revents = 0;
}
return (sig);
}
/* Call this before doing anything else. Sets up the socket pair
* and installs the signal handler */
int signal_init (void)
{
struct sigaction sa;
if (pipe (signal_pipe) == -1) {
logger (LOG_ERR, "pipe: %s", strerror (errno));
return (-1);
}
/* Stop any scripts from inheriting us */
close_on_exec (signal_pipe[0]);
close_on_exec (signal_pipe[1]);
/* Ignore child signals and don't make zombies.
* Because we do this, we don't need to be in signal_setup */
memset (&sa, 0, sizeof (sa));
sa.sa_handler = SIG_DFL;
sa.sa_flags = SA_NOCLDSTOP | SA_NOCLDWAIT;
if (sigaction (SIGCHLD, &sa, NULL) == -1) {
logger (LOG_ERR, "sigaction: %s", strerror (errno));
return (-1);
}
memset (signals, 0, sizeof (signals));
return (0);
}
int signal_setup (void)
{
unsigned int i;
struct sigaction sa;
memset (&sa, 0, sizeof (sa));
sa.sa_handler = signal_handler;
sigemptyset (&sa.sa_mask);
for (i = 0; i < sizeof (handle_sigs) / sizeof (handle_sigs[0]); i++)
if (sigaction (handle_sigs[i], &sa, NULL) == -1) {
logger (LOG_ERR, "sigaction: %s", strerror (errno));
return (-1);
}
return (0);
}
int signal_reset (void)
{
struct sigaction sa;
unsigned int i;
memset (&sa, 0, sizeof (sa));
sa.sa_handler = SIG_DFL;
sigemptyset (&sa.sa_mask);
for (i = 0; i < sizeof (handle_sigs) / sizeof (handle_sigs[0]); i++)
if (sigaction (handle_sigs[i], &sa, NULL) == -1) {
logger (LOG_ERR, "sigaction: %s", strerror (errno));
return (-1);
}
return (0);
}
