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  * $DragonFly: src/usr.sbin/i4b/isdnd/process.c,v 1.2 2003/06/17 04:29:54 dillon Exp $
  34  *
  35  *      last edit-date: [Mon Dec 13 21:48:19 1999]
  36  *
  37  *---------------------------------------------------------------------------*/
  38
  39 #include "isdnd.h"
  40
  41 /*---------------------------------------------------------------------------*
  42  *      check if another instance of us is already running
  43  *---------------------------------------------------------------------------*/
  44 void
  45 check_pid(void)
  46 {
  47         FILE *fp;
  48
  49         /* check if another lock-file already exists */
  50
  51         if((fp = fopen(PIDFILE, "r")) != NULL)
  52         {
  53                 /* lockfile found, check */
  54
  55                 int oldpid;
  56
  57                 /* read pid from file */
  58
  59                 if((fscanf(fp, "%d", &oldpid)) != 1)
  60                 {
  61                         dolog(LL_ERR, "ERROR, reading pid from lockfile failed, terminating!");
  62                         exit(1);
  63                 }
  64
  65                 /* check if process got from file is still alive */
  66
  67                 if((kill(oldpid, 0)) != 0)
  68                 {
  69                         /* process does not exist */
  70
  71                         /* close file */
  72
  73                         fclose(fp);
  74
  75                         DBGL(DL_PROC, (dolog(LL_DBG, "removing old lock-file %s", PIDFILE)));
  76
  77                         /* remove file */
  78
  79                         unlink(PIDFILE);
  80                 }
  81                 else
  82                 {
  83                         /* process is still alive */
  84
  85                         dolog(LL_ERR, "ERROR, another daemon is already running, pid = %d, terminating!", oldpid);
  86                         exit(1);
  87                 }
  88         }
  89 }
  90
  91 /*---------------------------------------------------------------------------*
  92  *      establish and init process lock file
  93  *---------------------------------------------------------------------------*/
  94 void
  95 write_pid(void)
  96 {
  97         FILE *fp;
  98
  99         /* write my pid into lock-file */
 100
 101         if((fp = fopen(PIDFILE, "w")) == NULL)
 102         {
 103                 dolog(LL_ERR, "ERROR, can't open lockfile for writing, terminating");
 104                 do_exit(1);
 105         }
 106
 107         if((fprintf(fp, "%d", (int)getpid())) == EOF)
 108         {
 109                 dolog(LL_ERR, "ERROR, can't write pid to lockfile, terminating");
 110                 do_exit(1);
 111         }
 112
 113         fsync(fileno(fp));
 114
 115         fclose(fp);
 116 }
 117
 118 /*---------------------------------------------------------------------------*
 119  *      become a daemon
 120  *---------------------------------------------------------------------------*/
 121 void
 122 daemonize(void)
 123 {
 124         int fd;
 125
 126         switch (fork())
 127         {
 128                 case -1:                /* error */
 129                         dolog(LL_ERR, "ERROR, daemonize/fork: %s", strerror(errno));
 130                         exit(1);
 131                 case 0:                 /* child */
 132                         break;
 133                 default:                /* parent */
 134                         exit(0);
 135         }
 136
 137         /* new session / no control tty */
 138
 139         if(setsid() == -1)
 140         {
 141                 dolog(LL_ERR, "ERROR, setsid returns: %s", strerror(errno));
 142                 exit(1);
 143         }
 144
 145         /* go away from mounted dir */
 146
 147         chdir("/");
 148
 149         /* move i/o to another device ? */
 150
 151         if(do_fullscreen && do_rdev)
 152         {
 153                 char *tp;
 154
 155                 if((fd = open(rdev, O_RDWR, 0)) != -1)
 156                 {
 157                         if(!isatty(fd))
 158                         {
 159                                 dolog(LL_ERR, "ERROR, device %s is not a tty!", rdev);
 160                                 exit(1);
 161                         }
 162                         if((dup2(fd, STDIN_FILENO)) == -1)
 163                         {
 164                                 dolog(LL_ERR, "ERROR, dup2 stdin: %s", strerror(errno));
 165                                 exit(1);
 166                         }
 167                         if((dup2(fd, STDOUT_FILENO)) == -1)
 168                         {
 169                                 dolog(LL_ERR, "ERROR, dup2 stdout: %s", strerror(errno));
 170                                 exit(1);
 171                         }
 172                         if((dup2(fd, STDERR_FILENO)) == -1)
 173                         {
 174                                 dolog(LL_ERR, "ERROR, dup2 stderr: %s", strerror(errno));
 175                                 exit(1);
 176                         }
 177                 }
 178                 else
 179                 {
 180                         dolog(LL_ERR, "ERROR, cannot open redirected device: %s", strerror(errno));
 181                         exit(1);
 182                 }
 183
 184                 if(fd > 2)
 185                 {
 186                         if((close(fd)) == -1)
 187                         {
 188                                 dolog(LL_ERR, "ERROR, close in daemonize: %s", strerror(errno));
 189                                 exit(1);
 190                         }
 191                 }
 192
 193                 /* curses output && fork NEEDS controlling tty */
 194
 195                 if((ioctl(STDIN_FILENO, TIOCSCTTY, NULL)) < 0)
 196                 {
 197                         dolog(LL_ERR, "ERROR, cannot setup tty as controlling terminal: %s", strerror(errno));
 198                         exit(1);
 199                 }
 200
 201                 /* in case there is no environment ... */
 202
 203                 if(((tp = getenv("TERM")) == NULL) || (*tp == '\0'))
 204                 {
 205                         if(do_ttytype == 0)
 206                         {
 207                                 dolog(LL_ERR, "ERROR, no environment variable TERM found and -t not specified!");
 208                                 exit(1);
 209                         }
 210
 211                         if((setenv("TERM", ttype, 1)) != 0)
 212                         {
 213                                 dolog(LL_ERR, "ERROR, setenv TERM=%s failed: %s", ttype, strerror(errno));
 214                                 exit(1);
 215                         }
 216                 }
 217         }
 218 }
 219
 220 /* EOF */