release/src/router/libdaemon/examples/testd.c

   1 /***
   2   This file is part of libdaemon.
   3
   4   Copyright 2003-2008 Lennart Poettering
   5
   6   libdaemon is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU Lesser General Public License as
   8   published by the Free Software Foundation, either version 2.1 of the
   9   License, or (at your option) any later version.
  10
  11   libdaemon is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public
  17   License along with libdaemon. If not, see
  18   <http://www.gnu.org/licenses/>.
  19 ***/
  20
  21 #include <signal.h>
  22 #include <errno.h>
  23 #include <string.h>
  24 #include <sys/types.h>
  25 #include <sys/time.h>
  26 #include <sys/unistd.h>
  27 #include <sys/select.h>
  28
  29 #include <libdaemon/dfork.h>
  30 #include <libdaemon/dsignal.h>
  31 #include <libdaemon/dlog.h>
  32 #include <libdaemon/dpid.h>
  33 #include <libdaemon/dexec.h>
  34
  35 int main(int argc, char *argv[]) {
  36     pid_t pid;
  37
  38     /* Reset signal handlers */
  39     if (daemon_reset_sigs(-1) < 0) {
  40         daemon_log(LOG_ERR, "Failed to reset all signal handlers: %s", strerror(errno));
  41         return 1;
  42     }
  43
  44     /* Unblock signals */
  45     if (daemon_unblock_sigs(-1) < 0) {
  46         daemon_log(LOG_ERR, "Failed to unblock all signals: %s", strerror(errno));
  47         return 1;
  48     }
  49
  50     /* Set indetification string for the daemon for both syslog and PID file */
  51     daemon_pid_file_ident = daemon_log_ident = daemon_ident_from_argv0(argv[0]);
  52
  53     /* Check if we are called with -k parameter */
  54     if (argc >= 2 && !strcmp(argv[1], "-k")) {
  55         int ret;
  56
  57         /* Kill daemon with SIGTERM */
  58
  59         /* Check if the new function daemon_pid_file_kill_wait() is available, if it is, use it. */
  60         if ((ret = daemon_pid_file_kill_wait(SIGTERM, 5)) < 0)
  61             daemon_log(LOG_WARNING, "Failed to kill daemon: %s", strerror(errno));
  62
  63         return ret < 0 ? 1 : 0;
  64     }
  65
  66     /* Check that the daemon is not rung twice a the same time */
  67     if ((pid = daemon_pid_file_is_running()) >= 0) {
  68         daemon_log(LOG_ERR, "Daemon already running on PID file %u", pid);
  69         return 1;
  70     }
  71
  72     /* Prepare for return value passing from the initialization procedure of the daemon process */
  73     if (daemon_retval_init() < 0) {
  74         daemon_log(LOG_ERR, "Failed to create pipe.");
  75         return 1;
  76     }
  77
  78     /* Do the fork */
  79     if ((pid = daemon_fork()) < 0) {
  80
  81         /* Exit on error */
  82         daemon_retval_done();
  83         return 1;
  84
  85     } else if (pid) { /* The parent */
  86         int ret;
  87
  88         /* Wait for 20 seconds for the return value passed from the daemon process */
  89         if ((ret = daemon_retval_wait(20)) < 0) {
  90             daemon_log(LOG_ERR, "Could not recieve return value from daemon process: %s", strerror(errno));
  91             return 255;
  92         }
  93
  94         daemon_log(ret != 0 ? LOG_ERR : LOG_INFO, "Daemon returned %i as return value.", ret);
  95         return ret;
  96
  97     } else { /* The daemon */
  98         int fd, quit = 0;
  99         fd_set fds;
 100
 101         /* Close FDs */
 102         if (daemon_close_all(-1) < 0) {
 103             daemon_log(LOG_ERR, "Failed to close all file descriptors: %s", strerror(errno));
 104
 105             /* Send the error condition to the parent process */
 106             daemon_retval_send(1);
 107             goto finish;
 108         }
 109
 110         /* Create the PID file */
 111         if (daemon_pid_file_create() < 0) {
 112             daemon_log(LOG_ERR, "Could not create PID file (%s).", strerror(errno));
 113             daemon_retval_send(2);
 114             goto finish;
 115         }
 116
 117         /* Initialize signal handling */
 118         if (daemon_signal_init(SIGINT, SIGTERM, SIGQUIT, SIGHUP, 0) < 0) {
 119             daemon_log(LOG_ERR, "Could not register signal handlers (%s).", strerror(errno));
 120             daemon_retval_send(3);
 121             goto finish;
 122         }
 123
 124         /*... do some further init work here */
 125
 126
 127         /* Send OK to parent process */
 128         daemon_retval_send(0);
 129
 130         daemon_log(LOG_INFO, "Sucessfully started");
 131
 132         /* Prepare for select() on the signal fd */
 133         FD_ZERO(&fds);
 134         fd = daemon_signal_fd();
 135         FD_SET(fd, &fds);
 136
 137         while (!quit) {
 138             fd_set fds2 = fds;
 139
 140             /* Wait for an incoming signal */
 141             if (select(FD_SETSIZE, &fds2, 0, 0, 0) < 0) {
 142
 143                 /* If we've been interrupted by an incoming signal, continue */
 144                 if (errno == EINTR)
 145                     continue;
 146
 147                 daemon_log(LOG_ERR, "select(): %s", strerror(errno));
 148                 break;
 149             }
 150
 151             /* Check if a signal has been recieved */
 152             if (FD_ISSET(fd, &fds2)) {
 153                 int sig;
 154
 155                 /* Get signal */
 156                 if ((sig = daemon_signal_next()) <= 0) {
 157                     daemon_log(LOG_ERR, "daemon_signal_next() failed: %s", strerror(errno));
 158                     break;
 159                 }
 160
 161                 /* Dispatch signal */
 162                 switch (sig) {
 163
 164                     case SIGINT:
 165                     case SIGQUIT:
 166                     case SIGTERM:
 167                         daemon_log(LOG_WARNING, "Got SIGINT, SIGQUIT or SIGTERM.");
 168                         quit = 1;
 169                         break;
 170
 171                     case SIGHUP:
 172                         daemon_log(LOG_INFO, "Got a HUP");
 173                         daemon_exec("/", NULL, "/bin/ls", "ls", (char*) NULL);
 174                         break;
 175
 176                 }
 177             }
 178         }
 179
 180         /* Do a cleanup */
 181 finish:
 182         daemon_log(LOG_INFO, "Exiting...");
 183         daemon_retval_send(255);
 184         daemon_signal_done();
 185         daemon_pid_file_remove();
 186
 187         return 0;
 188     }
 189 }