usr.sbin/i4b/isdnd/process.c

   1 /*
   2  * Copyright (c) 1997, 1999 Hellmuth Michaelis. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  16  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  19  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  20  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  23  * SUCH DAMAGE.
  24  *
  25  *---------------------------------------------------------------------------
  26  *
  27  *      i4b daemon - process handling routines
  28  *      --------------------------------------
  29  *
  30  *      $Id: process.c,v 1.8 1999/12/13 21:25:25 hm Exp $
  31  *
  32  * $FreeBSD: src/usr.sbin/i4b/isdnd/process.c,v 1.6.2.1 2001/08/01 17:45:03 obrien Exp $
  33  *
  34  *      last edit-date: [Mon Dec 13 21:48:19 1999]
  35  *
  36  *---------------------------------------------------------------------------*/
  37
  38 #include "isdnd.h"
  39
  40 /*---------------------------------------------------------------------------*
  41  *      check if another instance of us is already running
  42  *---------------------------------------------------------------------------*/
  43 void
  44 check_pid(void)
  45 {
  46         FILE *fp;
  47
  48         /* check if another lock-file already exists */
  49
  50         if((fp = fopen(PIDFILE, "r")) != NULL)
  51         {
  52                 /* lockfile found, check */
  53
  54                 int oldpid;
  55
  56                 /* read pid from file */
  57
  58                 if((fscanf(fp, "%d", &oldpid)) != 1)
  59                 {
  60                         log(LL_ERR, "ERROR, reading pid from lockfile failed, terminating!");
  61                         exit(1);
  62                 }
  63
  64                 /* check if process got from file is still alive */
  65
  66                 if((kill(oldpid, 0)) != 0)
  67                 {
  68                         /* process does not exist */
  69
  70                         /* close file */
  71
  72                         fclose(fp);
  73
  74                         DBGL(DL_PROC, (log(LL_DBG, "removing old lock-file %s", PIDFILE)));
  75
  76                         /* remove file */
  77
  78                         unlink(PIDFILE);
  79                 }
  80                 else
  81                 {
  82                         /* process is still alive */
  83
  84                         log(LL_ERR, "ERROR, another daemon is already running, pid = %d, terminating!", oldpid);
  85                         exit(1);
  86                 }
  87         }
  88 }
  89
  90 /*---------------------------------------------------------------------------*
  91  *      establish and init process lock file
  92  *---------------------------------------------------------------------------*/
  93 void
  94 write_pid(void)
  95 {
  96         FILE *fp;
  97
  98         /* write my pid into lock-file */
  99
 100         if((fp = fopen(PIDFILE, "w")) == NULL)
 101         {
 102                 log(LL_ERR, "ERROR, can't open lockfile for writing, terminating");
 103                 do_exit(1);
 104         }
 105
 106         if((fprintf(fp, "%d", (int)getpid())) == EOF)
 107         {
 108                 log(LL_ERR, "ERROR, can't write pid to lockfile, terminating");
 109                 do_exit(1);
 110         }
 111
 112         fsync(fileno(fp));
 113
 114         fclose(fp);
 115 }
 116
 117 /*---------------------------------------------------------------------------*
 118  *      become a daemon
 119  *---------------------------------------------------------------------------*/
 120 void
 121 daemonize(void)
 122 {
 123         int fd;
 124
 125         switch (fork())
 126         {
 127                 case -1:                /* error */
 128                         log(LL_ERR, "ERROR, daemonize/fork: %s", strerror(errno));
 129                         exit(1);
 130                 case 0:                 /* child */
 131                         break;
 132                 default:                /* parent */
 133                         exit(0);
 134         }
 135
 136         /* new session / no control tty */
 137
 138         if(setsid() == -1)
 139         {
 140                 log(LL_ERR, "ERROR, setsid returns: %s", strerror(errno));
 141                 exit(1);
 142         }
 143
 144         /* go away from mounted dir */
 145
 146         chdir("/");
 147
 148         /* move i/o to another device ? */
 149
 150         if(do_fullscreen && do_rdev)
 151         {
 152                 char *tp;
 153
 154                 if((fd = open(rdev, O_RDWR, 0)) != -1)
 155                 {
 156                         if(!isatty(fd))
 157                         {
 158                                 log(LL_ERR, "ERROR, device %s is not a tty!", rdev);
 159                                 exit(1);
 160                         }
 161                         if((dup2(fd, STDIN_FILENO)) == -1)
 162                         {
 163                                 log(LL_ERR, "ERROR, dup2 stdin: %s", strerror(errno));
 164                                 exit(1);
 165                         }
 166                         if((dup2(fd, STDOUT_FILENO)) == -1)
 167                         {
 168                                 log(LL_ERR, "ERROR, dup2 stdout: %s", strerror(errno));
 169                                 exit(1);
 170                         }
 171                         if((dup2(fd, STDERR_FILENO)) == -1)
 172                         {
 173                                 log(LL_ERR, "ERROR, dup2 stderr: %s", strerror(errno));
 174                                 exit(1);
 175                         }
 176                 }
 177                 else
 178                 {
 179                         log(LL_ERR, "ERROR, cannot open redirected device: %s", strerror(errno));
 180                         exit(1);
 181                 }
 182
 183                 if(fd > 2)
 184                 {
 185                         if((close(fd)) == -1)
 186                         {
 187                                 log(LL_ERR, "ERROR, close in daemonize: %s", strerror(errno));
 188                                 exit(1);
 189                         }
 190                 }
 191
 192                 /* curses output && fork NEEDS controlling tty */
 193
 194                 if((ioctl(STDIN_FILENO, TIOCSCTTY, (char *)NULL)) < 0)
 195                 {
 196                         log(LL_ERR, "ERROR, cannot setup tty as controlling terminal: %s", strerror(errno));
 197                         exit(1);
 198                 }
 199
 200                 /* in case there is no environment ... */
 201
 202                 if(((tp = getenv("TERM")) == NULL) || (*tp == '\0'))
 203                 {
 204                         if(do_ttytype == 0)
 205                         {
 206                                 log(LL_ERR, "ERROR, no environment variable TERM found and -t not specified!");
 207                                 exit(1);
 208                         }
 209
 210                         if((setenv("TERM", ttype, 1)) != 0)
 211                         {
 212                                 log(LL_ERR, "ERROR, setenv TERM=%s failed: %s", ttype, strerror(errno));
 213                                 exit(1);
 214                         }
 215                 }
 216         }
 217 }
 218
 219 /* EOF */