| /* |
| * 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); |
| } |
| |