Pinkbyte/yasnd
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Revert "remove unneeded fork(for now)"

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This reverts commit 955aeb64b7.
Implement pid file management and locking. Only single instance of daemon is allowed
This commit is contained in:
Sergey Popov 2012-01-03 03:48:26 +04:00
parent 1610c1394f
commit 9668922f8f
1 changed files with 45 additions and 0 deletions
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45
yasnd.c
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@ -8,6 +8,7 @@
#include "yasnd.h"
cfg_t *cfg; // pointer to configuration structure
char pidfile[]="/var/run/yasnd.pid"; // pidfile path
host_decl* hosts=NULL; // structure with hosts' definitions
int hosts_count=0; // count of hosts
int debug_flag=0;
@ -94,6 +95,28 @@ int cb_validate_host(cfg_t *cfg, cfg_opt_t *opt)
return 0; // success
}
void pidfile_init()
{
int pidfile_d=open(pidfile,O_RDWR|O_CREAT,0640);
/* Can not open/create pidfile? */
if (pidfile_d<0)
{
log_event("Error: can not open/create pid file");
exit(EXIT_FAILURE);
}
/* Can not lock pidfile? */
if (lockf(pidfile_d,F_TLOCK,0)<0)
{
log_event("Error: can not lock pid file, maybe another yasnd instance still running?");
exit(EXIT_FAILURE);
}
/* First daemon instance continues */
char pidstr[20];
sprintf(pidstr,"%d\n",getpid());
/* Record pid to pidfile and hold it */
write(pidfile_d,pidstr,strlen(pidstr));
}
void init()
{
static cfg_opt_t host_opts[] = {
@ -311,6 +334,8 @@ void signal_handler(int signum)
// free hosts structures memory
if (hosts!=NULL)
free(hosts);
// remove pid file
remove(pidfile);
}
if (signum==SIGHUP)
@ -366,12 +391,29 @@ int main(int argc, char *argv[])
/* Our process ID and Session ID */
pid_t pid, sid;
/* Fork off the parent process */
pid = fork();
if (pid < 0) {
exit(EXIT_FAILURE);
}
/* If we got a good PID, then we can exit the parent process. */
if (pid > 0) {
exit(EXIT_SUCCESS);
}
/* Change the file mode mask */
umask(0);
/* Open any logs here */
openlog("yasnd", LOG_PID|LOG_CONS, LOG_USER);
/* Create a new SID for the child process */
sid = setsid();
if (sid < 0) {
/* Log the failure */
exit(EXIT_FAILURE);
}
/* Change the current working directory */
if ((chdir("/")) < 0) {
/* Log the failure */
@ -383,6 +425,9 @@ int main(int argc, char *argv[])
close(STDOUT_FILENO);
close(STDERR_FILENO);
// create pid file and write current process pid
pidfile_init();
// initialize IPC queue and create process
// that will watch for new messages in it
ipc_init();