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/* Process handling
*
* Copyright © 2006, Thomas Bernard
* Copyright © 2013, Benoît Knecht <benoit.knecht@fsfe.org>
*
* 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.
* * The name of the author may not 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 LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <signal.h>
#include <sys/wait.h>
#include "process.h"
#include "config.h"
#include "log.h"
static const int max_number_of_children = 5;
static int number_of_children = 0;
pid_t
process_fork(void)
{
if (number_of_children >= max_number_of_children)
{
errno = EAGAIN;
return -1;
}
pid_t pid = fork();
if (pid > 0)
++number_of_children;
return pid;
}
void
process_handle_child_termination(int signal)
{
waitpid(-1, NULL, WNOHANG);
--number_of_children;
}
int
process_daemonize(void)
{
int pid;
#ifndef USE_DAEMON
int i;
switch(process_fork())
{
/* fork error */
case -1:
perror("fork()");
exit(1);
/* child process */
case 0:
/* obtain a new process group */
if( (pid = setsid()) < 0)
{
perror("setsid()");
exit(1);
}
/* close all descriptors */
for (i=getdtablesize();i>=0;--i) close(i);
i = open("/dev/null",O_RDWR); /* open stdin */
dup(i); /* stdout */
dup(i); /* stderr */
umask(027);
chdir("/");
break;
/* parent process */
default:
exit(0);
}
#else
if( daemon(0, 0) < 0 )
perror("daemon()");
pid = getpid();
#endif
return pid;
}
int
process_check_if_running(const char *fname)
{
char buffer[64];
int pidfile;
pid_t pid;
if(!fname || *fname == '\0')
return -1;
if( (pidfile = open(fname, O_RDONLY)) < 0)
return 0;
memset(buffer, 0, 64);
if(read(pidfile, buffer, 63))
{
if( (pid = atol(buffer)) > 0)
{
if(!kill(pid, 0))
{
close(pidfile);
return -2;
}
}
}
close(pidfile);
return 0;
}