mirror of
https://github.com/sheumann/hush.git
synced 2024-11-05 21:04:56 +00:00
78 lines
2.1 KiB
C
78 lines
2.1 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/* signalpipe.c
|
|
*
|
|
* Signal pipe infrastructure. A reliable way of delivering signals.
|
|
*
|
|
* Russ Dill <Russ.Dill@asu.edu> December 2003
|
|
*
|
|
* 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 2 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, write to the Free Software
|
|
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
|
|
#include "common.h"
|
|
|
|
|
|
static int signal_pipe[2];
|
|
|
|
static void signal_handler(int sig)
|
|
{
|
|
if (send(signal_pipe[1], &sig, sizeof(sig), MSG_DONTWAIT) < 0)
|
|
bb_perror_msg("cannot send signal");
|
|
}
|
|
|
|
|
|
/* Call this before doing anything else. Sets up the socket pair
|
|
* and installs the signal handler */
|
|
void udhcp_sp_setup(void)
|
|
{
|
|
socketpair(AF_UNIX, SOCK_STREAM, 0, signal_pipe);
|
|
fcntl(signal_pipe[0], F_SETFD, FD_CLOEXEC);
|
|
fcntl(signal_pipe[1], F_SETFD, FD_CLOEXEC);
|
|
signal(SIGUSR1, signal_handler);
|
|
signal(SIGUSR2, signal_handler);
|
|
signal(SIGTERM, signal_handler);
|
|
}
|
|
|
|
|
|
/* Quick little function to setup the rfds. Will return the
|
|
* max_fd for use with select. Limited in that you can only pass
|
|
* one extra fd */
|
|
int udhcp_sp_fd_set(fd_set *rfds, int extra_fd)
|
|
{
|
|
FD_ZERO(rfds);
|
|
FD_SET(signal_pipe[0], rfds);
|
|
if (extra_fd >= 0) {
|
|
fcntl(extra_fd, F_SETFD, FD_CLOEXEC);
|
|
FD_SET(extra_fd, rfds);
|
|
}
|
|
return signal_pipe[0] > extra_fd ? signal_pipe[0] : extra_fd;
|
|
}
|
|
|
|
|
|
/* 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 udhcp_sp_read(fd_set *rfds)
|
|
{
|
|
int sig;
|
|
|
|
if (!FD_ISSET(signal_pipe[0], rfds))
|
|
return 0;
|
|
|
|
if (read(signal_pipe[0], &sig, sizeof(sig)) < 0)
|
|
return -1;
|
|
|
|
return sig;
|
|
}
|