xdasd_unix.c

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/*----------------------------------------------------------------------------
 * Copyright (c) 2006, Novell, Inc.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are 
 * met:
 * 
 *     * Redistributions of source code must retain the above copyright 
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright 
 *       notice, this list of conditions and the following disclaimer in the 
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Novell nor the names of its contributors 
 *       may be used to endorse or promote products derived from this 
 *       software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
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 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *--------------------------------------------------------------------------*/

#include "xdasd_main.h"
#include "xdasd_log.h"
#include "xdasd_cmdline.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
#include <unistd.h>

static int xdasd_check_pid(const char * pidfile)
{
   pid_t pid;
   FILE * f;
   char pidstr[14] = {0};

   /* make sure that we're not already running */
   if ((f = fopen(pidfile, "r")) != 0)
   {
      fgets(pidstr, sizeof(pidstr), f);
      pid = atoi(pidstr);
      if (pid && kill(pid, 0) == 0)
         return -1;  /* already running */
      fclose(f);
   }
   return 0;
}

static int xdasd_write_pid(const char * pidfile, pid_t pid)
{
   FILE * f;

   if ((f = fopen(pidfile, "w")) == 0)
      return -1;

   fprintf(f, "%i", (int)pid);
   fclose(f);
   return 0;
}

static int xdasd_daemonize(void)
{
   int i;
   pid_t pid;

   switch (pid = fork())
   {
      case -1: return -1;  /* Error! (errno is set) */
      case  0: break;      /* The child. */
      default:             /* The parent - just die. */
         exit(0);
   }

   /* child continues... */
   setsid();

   chdir("/");

   umask(0);

   for (i = 0; i < 64; i++)
      close(i);

   return 0;
}

static void xdasd_signal_handler(int signum)
{
   switch(signum)
   {
      case SIGALRM: xdasd_set_signal(XDASD_SIGALRM); break;
      case SIGTERM: xdasd_set_signal(XDASD_SIGTERM); break;
      case SIGHUP:  xdasd_set_signal(XDASD_SIGHUP);  break;
   }
}

static int xdasd_setup_signal_handler(void)
{
   int result;
   struct sigaction sa;

   sa.sa_handler = xdasd_signal_handler;
   sigemptyset(&sa.sa_mask);
   sa.sa_flags = 0;

#ifdef HAVE_SA_RESTORER
   sa.sa_restorer = 0;
#endif

   result =  sigaction(SIGALRM, &sa, 0);
   result |= sigaction(SIGTERM, &sa, 0);
   result |= sigaction(SIGPIPE, &sa, 0);
   result |= sigaction(SIGHUP,  &sa, 0);

   signal(SIGHUP, xdasd_signal_handler);
   return result;
}

int main(int argc, char ** argv) 
{
   int err;
   XDASDCmdLine cmdline;
   char pidfile[FILENAME_MAX];

   if (xdasd_parse_cmdline(argc, argv, &cmdline) < 0)
      xdasd_fatal("Invalid command line.\n");

   /* create runpath if necessary, build pid file path */
   mkdir(cmdline.runpath, 0777);
   snprintf(pidfile, sizeof(pidfile), "%s/" XDASD_PIDFNAME, cmdline.runpath);

   if (xdasd_check_pid(pidfile))
      xdasd_fatal("xdasd is already running. Check %s.\n", pidfile);

   if (cmdline.detach && xdasd_daemonize() < 0)
      xdasd_fatal("Could not daemonize (%d).\n", errno);

   if (xdasd_setup_signal_handler())
      xdasd_fatal("Error setting up signal handlers (%d).\n", errno);

   if ((err = xdasd_main_init(&cmdline)) == 0)
   {
      xdasd_write_pid(pidfile, getpid());
      xdasd_main_run();
   }
   return err;
}