release/src/router/minidlna/daemonize.c

   1 /* $Id: daemonize.c,v 1.4 2011/02/15 02:46:28 jmaggard Exp $ */
   2 /* MiniUPnP project
   3  * http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
   4  *
   5  * Copyright (c) 2006, Thomas Bernard
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *     * Redistributions of source code must retain the above copyright
  11  *       notice, this list of conditions and the following disclaimer.
  12  *     * Redistributions in binary form must reproduce the above copyright
  13  *       notice, this list of conditions and the following disclaimer in the
  14  *       documentation and/or other materials provided with the distribution.
  15  *     * The name of the author may not be used to endorse or promote products
  16  *       derived from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  19  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  22  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28  * POSSIBILITY OF SUCH DAMAGE.
  29  */
  30 #include <sys/types.h>
  31 #include <sys/stat.h>
  32 #include <unistd.h>
  33 #include <fcntl.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <errno.h>
  37 #include <string.h>
  38 #include <signal.h>
  39
  40 #include "daemonize.h"
  41 #include "config.h"
  42 #include "log.h"
  43
  44 #ifndef USE_DAEMON
  45
  46 int
  47 daemonize(void)
  48 {
  49         int pid, i;
  50
  51         switch(fork())
  52         {
  53         /* fork error */
  54         case -1:
  55                 perror("fork()");
  56                 exit(1);
  57
  58         /* child process */
  59         case 0:
  60                 /* obtain a new process group */
  61                 if( (pid = setsid()) < 0)
  62                 {
  63                         perror("setsid()");
  64                         exit(1);
  65                 }
  66
  67                 /* close all descriptors */
  68                 for (i=getdtablesize();i>=0;--i) close(i);
  69
  70                 i = open("/dev/null",O_RDWR); /* open stdin */
  71                 dup(i); /* stdout */
  72                 dup(i); /* stderr */
  73
  74                 umask(027);
  75                 chdir("/"); /* chdir to /tmp ? */
  76
  77                 return pid;
  78
  79         /* parent process */
  80         default:
  81                 exit(0);
  82         }
  83 }
  84 #endif
  85
  86 int
  87 writepidfile(const char * fname, int pid)
  88 {
  89         char pidstring[16];
  90         int pidstringlen;
  91         int pidfile;
  92
  93         if(!fname || (strlen(fname) == 0))
  94                 return -1;
  95
  96         if( (pidfile = open(fname, O_WRONLY|O_CREAT, 0644)) < 0)
  97         {
  98                 DPRINTF(E_INFO, L_GENERAL, "Unable to open pidfile for writing %s: %s\n", fname, strerror(errno));
  99                 return -1;
 100         }
 101
 102         pidstringlen = snprintf(pidstring, sizeof(pidstring), "%d\n", pid);
 103         if(pidstringlen <= 0)
 104         {
 105                 DPRINTF(E_INFO, L_GENERAL,
 106                         "Unable to write to pidfile %s: snprintf(): FAILED\n", fname);
 107                 close(pidfile);
 108                 return -1;
 109         }
 110         else
 111         {
 112                 if(write(pidfile, pidstring, pidstringlen) < 0)
 113                         DPRINTF(E_INFO, L_GENERAL, "Unable to write to pidfile %s: %s\n", fname, strerror(errno));
 114         }
 115
 116         close(pidfile);
 117
 118         return 0;
 119 }
 120
 121 int
 122 checkforrunning(const char * fname)
 123 {
 124         char buffer[64];
 125         int pidfile;
 126         pid_t pid;
 127
 128         if(!fname || (strlen(fname) == 0))
 129                 return -1;
 130
 131         if( (pidfile = open(fname, O_RDONLY)) < 0)
 132                 return 0;
 133
 134         memset(buffer, 0, 64);
 135
 136         if(read(pidfile, buffer, 63))
 137         {
 138                 if( (pid = atol(buffer)) > 0)
 139                 {
 140                         if(!kill(pid, 0))
 141                         {
 142                                 close(pidfile);
 143                                 return -2;
 144                         }
 145                 }
 146         }
 147
 148         close(pidfile);
 149
 150         return 0;
 151 }
 152