pikeyd165 – Rev 1
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/**** daemon.c *****************************/
/* M. Moller 2013-01-16 */
/* Univeral RPi GPIO keyboard daemon */
/*******************************************/
/*
Copyright (C) 2013 Michael Moller.
This file is part of the Universal Raspberry Pi GPIO keyboard daemon.
This is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The software 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA.
*/
#include <stdio.h>
#include <signal.h>
#include <syslog.h>
#include <errno.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include "daemon.h"
#define DAEMON_NAME "pikeyd"
void daemonShutdown(void);
void signal_handler(int sig);
void daemonize(char *rundir, char *pidfile);
int pid_fd;
char *pid_lock_file;
void daemonShutdown(void)
{
close(pid_fd);
unlink(pid_lock_file);
}
void signal_handler(int sig)
{
switch(sig){
case SIGHUP:
syslog(LOG_WARNING, "Received SIGHUP.");
break;
case SIGINT:
case SIGTERM:
syslog(LOG_INFO, "Exiting.");
daemonShutdown();
exit(0);
break;
default:
syslog(LOG_WARNING, "Unhandled signal %s", strsignal(sig));
}
}
/* get the pid from the pid lock file and terminate the daemon */
void daemonKill(char *pidfile)
{
int n;
pid_t pid;
char str[10];
pid_fd = open(pidfile, O_RDONLY, 0600);
if(pid_fd < 0){
perror(pidfile);
}
else{
if( read(pid_fd, str, 10) > 0 ){
pid = strtol(str, NULL, 0);
if(pid){
printf("terminating %d\n", pid);
n = kill(pid, SIGTERM);
if(n<0){
perror("kill");
}
}
}
close(pid_fd);
}
}
void daemonize(char *rundir, char *pidfile)
{
int pid, sid, i, r;
char str[10];
struct sigaction newSA;
sigset_t newSS;
if(getppid() == 1){
/* don't need to do it twice */
return;
}
setlogmask(LOG_UPTO(LOG_INFO));
openlog(DAEMON_NAME, LOG_CONS | LOG_PERROR, LOG_USER);
syslog(LOG_INFO, "Daemon starting");
sigemptyset(&newSS);
sigaddset(&newSS, SIGCHLD);
sigaddset(&newSS, SIGTSTP);
sigaddset(&newSS, SIGTTOU);
sigaddset(&newSS, SIGTTIN);
sigprocmask(SIG_BLOCK, &newSS, NULL); /* block these signals */
newSA.sa_handler = signal_handler;
sigemptyset(&newSA.sa_mask);
newSA.sa_flags = 0;
sigaction(SIGHUP, &newSA, NULL);
sigaction(SIGTERM, &newSA, NULL);
sigaction(SIGINT, &newSA, NULL);
pid = fork();
if(pid < 0){
perror("fork");
exit(EXIT_FAILURE);
}
if(pid > 0){ /* success. terminate the parent */
exit(0);
}
/* child continues here. */
umask(027);
sid = setsid();
if(sid < 0){
perror("set SID");
exit(EXIT_FAILURE);
}
for(i = getdtablesize(); i>=0; --i){
close(i);
}
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
if( chdir(rundir) < 0 ){
perror(rundir);
}
/* only one at a time */
pid_lock_file = pidfile;
pid_fd = open(pidfile, O_RDWR|O_CREAT, 0600);
if(pid_fd < 0){
syslog(LOG_INFO, "Could not open lock file %s. Exiting.", pidfile);
exit(EXIT_FAILURE);
}
if(lockf(pid_fd, F_TLOCK, 0) < 0){
syslog(LOG_INFO, "Could not lock lock file %s. Exiting.", pidfile);
unlink(pidfile);
exit(EXIT_FAILURE);
}
sprintf(str, "%d\n", getpid());
if( write(pid_fd, str, strlen(str)) < 0 ){
perror(pidfile);
}
syslog(LOG_INFO, "Daemon running.");
}