release/src/router/minidlna/daemonize.c

   1 /* MiniUPnP project
   2  * http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
   3  *
   4  * Copyright (c) 2006, Thomas Bernard
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions are met:
   9  *     * Redistributions of source code must retain the above copyright
  10  *       notice, this list of conditions and the following disclaimer.
  11  *     * Redistributions in binary form must reproduce the above copyright
  12  *       notice, this list of conditions and the following disclaimer in the
  13  *       documentation and/or other materials provided with the distribution.
  14  *     * The name of the author may not be used to endorse or promote products
  15  *       derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  18  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  21  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  27  * POSSIBILITY OF SUCH DAMAGE.
  28  */
  29 #include <sys/types.h>
  30 #include <sys/stat.h>
  31 #include <unistd.h>
  32 #include <fcntl.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <errno.h>
  36 #include <string.h>
  37 #include <signal.h>
  38
  39 #include "daemonize.h"
  40 #include "config.h"
  41 #include "log.h"
  42
  43 int
  44 daemonize(void)
  45 {
  46         int pid;
  47 #ifndef USE_DAEMON
  48         int i;
  49
  50         switch(fork())
  51         {
  52         /* fork error */
  53         case -1:
  54                 perror("fork()");
  55                 exit(1);
  56
  57         /* child process */
  58         case 0:
  59                 /* obtain a new process group */
  60                 if( (pid = setsid()) < 0)
  61                 {
  62                         perror("setsid()");
  63                         exit(1);
  64                 }
  65
  66                 /* close all descriptors */
  67                 for (i=getdtablesize();i>=0;--i) close(i);
  68
  69                 i = open("/dev/null",O_RDWR); /* open stdin */
  70                 dup(i); /* stdout */
  71                 dup(i); /* stderr */
  72
  73                 umask(027);
  74                 chdir("/");
  75
  76                 break;
  77         /* parent process */
  78         default:
  79                 exit(0);
  80         }
  81 #else
  82         if( daemon(0, 0) < 0 )
  83                 perror("daemon()");
  84         pid = getpid();
  85 #endif
  86         return pid;
  87 }
  88
  89 int
  90 writepidfile(const char * fname, int pid)
  91 {
  92         char pidstring[16];
  93         int pidstringlen;
  94         int pidfile;
  95
  96         if(!fname || (strlen(fname) == 0))
  97                 return -1;
  98
  99         if( (pidfile = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0644)) < 0)
 100         {
 101                 DPRINTF(E_INFO, L_GENERAL, "Unable to open pidfile for writing %s: %s\n", fname, strerror(errno));
 102                 return -1;
 103         }
 104
 105         pidstringlen = snprintf(pidstring, sizeof(pidstring), "%d\n", pid);
 106         if(pidstringlen <= 0)
 107         {
 108                 DPRINTF(E_INFO, L_GENERAL,
 109                         "Unable to write to pidfile %s: snprintf(): FAILED\n", fname);
 110                 close(pidfile);
 111                 return -1;
 112         }
 113         else
 114         {
 115                 if(write(pidfile, pidstring, pidstringlen) < 0)
 116                         DPRINTF(E_INFO, L_GENERAL, "Unable to write to pidfile %s: %s\n", fname, strerror(errno));
 117         }
 118
 119         close(pidfile);
 120
 121         return 0;
 122 }
 123
 124 int
 125 checkforrunning(const char * fname)
 126 {
 127         char buffer[64];
 128         int pidfile;
 129         pid_t pid;
 130
 131         if(!fname || (strlen(fname) == 0))
 132                 return -1;
 133
 134         if( (pidfile = open(fname, O_RDONLY)) < 0)
 135                 return 0;
 136
 137         memset(buffer, 0, 64);
 138
 139         if(read(pidfile, buffer, 63))
 140         {
 141                 if( (pid = atol(buffer)) > 0)
 142                 {
 143                         if(!kill(pid, 0))
 144                         {
 145                                 close(pidfile);
 146                                 return -2;
 147                         }
 148                 }
 149         }
 150
 151         close(pidfile);
 152
 153         return 0;
 154 }
 155