1
0
Fork 0
mirror of https://github.com/warmcat/libwebsockets.git synced 2025-03-09 00:00:04 +01:00

include daemonization file whoops

Signed-off-by: Andy Green <andy.green@linaro.org>
This commit is contained in:
Andy Green 2013-01-17 15:49:27 +08:00
parent eff73742bc
commit b2de95d2d4

151
lib/daemonize.c Normal file
View file

@ -0,0 +1,151 @@
/*
* This code is mainly taken from Doug Potter's page
*
* http://www-theorie.physik.unizh.ch/~dpotter/howto/daemonize
*
* I contacted him 2007-04-16 about the license for the original code,
* he replied it is Public Domain. Use the URL above to get the original
* Public Domain version if you want it.
*
* This version is LGPL2 and is (c)2006 - 2013 Andy Green <andy@warmcat.com>
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <limits.h>
#include <unistd.h>
#include <errno.h>
static int pid_daemon;
static char lock_path[PATH_MAX];
static void child_handler(int signum)
{
int fd;
char sz[20];
switch (signum) {
case SIGALRM: /* timedout daemonizing */
exit(1);
break;
case SIGUSR1: /* positive confirmation we daemonized well */
/* Create the lock file as the current user */
fd = open(lock_path, O_TRUNC | O_RDWR | O_CREAT, 0640);
if (fd < 0) {
fprintf(stderr, "unable to create lock"
" file %s, code=%d (%s)",
lock_path, errno, strerror(errno));
exit(1);
}
sprintf(sz, "%u", pid_daemon);
write(fd, sz, strlen(sz));
close(fd);
exit(0);
case SIGCHLD: /* daemonization failed */
exit(1);
break;
}
}
/*
* You just need to call this from your main(), when it
* returns you are all set "in the background" decoupled
* from the console you were started from.
*
* The process context you called from has been terminated then.
*/
int lws_daemonize(const char *_lock_path)
{
pid_t sid, parent;
/* already a daemon */
if (getppid() == 1)
return (1);
strncpy(lock_path, _lock_path, sizeof lock_path);
lock_path[sizeof(lock_path) - 1] = '\0';
/* Trap signals that we expect to recieve */
signal(SIGCHLD, child_handler); /* died */
signal(SIGUSR1, child_handler); /* was happy */
signal(SIGALRM, child_handler); /* timeout daemonizing */
/* Fork off the parent process */
pid_daemon = fork();
if (pid_daemon < 0) {
fprintf(stderr, "unable to fork daemon, code=%d (%s)",
errno, strerror(errno));
exit(1);
}
/* If we got a good PID, then we can exit the parent process. */
if (pid_daemon > 0) {
/*
* Wait for confirmation signal from the child via
* SIGCHILD / USR1, or for two seconds to elapse
* (SIGALRM). pause() should not return.
*/
alarm(2);
pause();
/* should not be reachable */
exit(1);
}
/* At this point we are executing as the child process */
parent = getppid();
/* Cancel certain signals */
signal(SIGCHLD, SIG_DFL); /* A child process dies */
signal(SIGTSTP, SIG_IGN); /* Various TTY signals */
signal(SIGTTOU, SIG_IGN);
signal(SIGTTIN, SIG_IGN);
signal(SIGHUP, SIG_IGN); /* Ignore hangup signal */
/* Change the file mode mask */
umask(0);
/* Create a new SID for the child process */
sid = setsid();
if (sid < 0) {
fprintf(stderr,
"unable to create a new session, code %d (%s)",
errno, strerror(errno));
exit(1);
}
/*
* Change the current working directory. This prevents the current
* directory from being locked; hence not being able to remove it.
*/
if ((chdir("/")) < 0) {
fprintf(stderr,
"unable to change directory to %s, code %d (%s)",
"/", errno, strerror(errno));
exit(1);
}
/* Redirect standard files to /dev/null */
freopen("/dev/null", "r", stdin);
freopen("/dev/null", "w", stdout);
freopen("/dev/null", "w", stderr);
/* Tell the parent process that we are A-okay */
kill(parent, SIGUSR1);
/* return to continue what is now "the daemon" */
return (0);
}