/* * dhcpcd - DHCP client daemon * Copyright 2006-2008 Roy Marples * 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 #include #include #include #include #include #include #include "common.h" #include "signals.h" static int signal_pipe[2]; static const int handle_sigs[] = { SIGHUP, SIGALRM, SIGTERM, SIGINT }; static void signal_handler(int sig) { int serrno = errno; if (write(signal_pipe[1], &sig, sizeof(sig)) != sizeof(sig)) syslog(LOG_ERR, "write signal %d: %s", sig, strerror(errno)); /* Restore errno */ errno = serrno; } int signal_fd(void) { return (signal_pipe[0]); } /* 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 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); }