release/src/router/miniupnpd/daemonize.c

   1 /* $Id: daemonize.c,v 1.13 2012/03/05 20:36:15 nanard Exp $ */
   2 /* MiniUPnP project
   3  * http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
   4  * (c) 2006 Thomas Bernard
   5  * This software is subject to the conditions detailed
   6  * in the LICENCE file provided within the distribution */
   7
   8 #include <sys/types.h>
   9 #include <sys/stat.h>
  10 #include <unistd.h>
  11 #include <fcntl.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <syslog.h>
  15 #include <string.h>
  16 #include <signal.h>
  17
  18 #include "daemonize.h"
  19 #include "config.h"
  20
  21 #ifndef USE_DAEMON
  22
  23 int
  24 daemonize(void)
  25 {
  26         int pid, i;
  27
  28         switch(fork())
  29         {
  30         /* fork error */
  31         case -1:
  32                 perror("fork()");
  33                 exit(1);
  34
  35         /* child process */
  36         case 0:
  37                 /* obtain a new process group */
  38                 if( (pid = setsid()) < 0)
  39                 {
  40                         perror("setsid()");
  41                         exit(1);
  42                 }
  43
  44                 /* close all descriptors */
  45                 for (i=getdtablesize();i>=0;--i) close(i);
  46
  47                 i = open("/dev/null", O_RDWR); /* open stdin */
  48                 dup(i); /* stdout */
  49                 dup(i); /* stderr */
  50
  51                 umask(027);
  52                 chdir("/"); /* chdir to /tmp ? */
  53
  54                 return pid;
  55
  56         /* parent process */
  57         default:
  58                 exit(0);
  59         }
  60 }
  61 #endif
  62
  63 int
  64 writepidfile(const char * fname, int pid)
  65 {
  66         char pidstring[16];
  67         int pidstringlen;
  68         int pidfile;
  69
  70         if(!fname || (strlen(fname) == 0))
  71                 return -1;
  72
  73         if( (pidfile = open(fname, O_WRONLY|O_CREAT, 0644)) < 0)
  74         {
  75                 syslog(LOG_ERR, "Unable to open pidfile for writing %s: %m", fname);
  76                 return -1;
  77         }
  78
  79         pidstringlen = snprintf(pidstring, sizeof(pidstring), "%d\n", pid);
  80         if(pidstringlen <= 0)
  81         {
  82                 syslog(LOG_ERR,
  83                         "Unable to write to pidfile %s: snprintf(): FAILED", fname);
  84                 close(pidfile);
  85                 return -1;
  86         }
  87         else
  88         {
  89                 if(write(pidfile, pidstring, pidstringlen) < 0)
  90                         syslog(LOG_ERR, "Unable to write to pidfile %s: %m", fname);
  91         }
  92
  93         close(pidfile);
  94
  95         return 0;
  96 }
  97
  98 int
  99 checkforrunning(const char * fname)
 100 {
 101         char buffer[64];
 102         int pidfile;
 103         pid_t pid;
 104
 105         if(!fname || (strlen(fname) == 0))
 106                 return -1;
 107
 108         if( (pidfile = open(fname, O_RDONLY)) < 0)
 109                 return 0;
 110
 111         memset(buffer, 0, 64);
 112
 113         if(read(pidfile, buffer, 63))
 114         {
 115                 if( (pid = atol(buffer)) > 0)
 116                 {
 117                         if(!kill(pid, 0))
 118                         {
 119                                 close(pidfile);
 120                                 return -2;
 121                         }
 122                 }
 123         }
 124
 125         close(pidfile);
 126
 127         return 0;
 128 }
 129