Linuxでのデーモンの作成
8608 ワード
引用:Creating a daemon in Linux-Pascal Werkl
/*
* daemonize.c
* This example daemonizes a process, writes a few log messages,
* sleeps 20 seconds and terminates afterwards.
*/
#include
#include
#include
#include
#include
static void skeleton_daemon()
{
pid_t pid;
/* Fork off the parent process */
pid = fork();
/* An error occurred */
if (pid < 0)
exit(EXIT_FAILURE);
/* Success: Let the parent terminate */
if (pid > 0)
exit(EXIT_SUCCESS);
/* On Success: The child process becomes session leader */
if (setsid() < 0)
exit(EXIT_FAILURE);
/* Catch, ignore and handle signals */
//TODO: Implement a working signal handler
signal(SIGCHLD, SIG_IGN);
signal(SIGHUP, SIG_IGN);
/* Fork off for the second time */
pid = fork();
/* An error occurred */
if (pid < 0)
exit(EXIT_FAILURE);
/* Success: Let the parent terminate */
if (pid > 0)
exit(EXIT_SUCCESS);
/* Set new file permissions */
umask(0);
/* Change the working directory to the root directory */
/* or another appropriated directory */
chdir("/");
/* Close all open file descriptors */
int x;
for (x = sysconf(_SC_OPEN_MAX); x>=0; x--)
{
close(x);
}
/* Open the log file */
openlog("firstdaemon", LOG_PID, LOG_DAEMON);
}
int main()
{
skeleton_daemon();
while (1)
{
//TODO: Insert daemon code here.
syslog(LOG_NOTICE, "First daemon started.");
sleep(20);
break;
}
syslog(LOG_NOTICE, "First daemon terminated.");
closelog();
return EXIT_SUCCESS;
}