/*
 * Copyright 2007, Haiku, Inc. All Rights Reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *              Axel Dörfler, axeld@pinc-software.de
 */

#include <fcntl.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>


static void
restore_old_sighup(int result, struct sigaction *action)
{
        if (result != -1)
                sigaction(SIGHUP, action, NULL);
}


int
daemon(int noChangeDir, int noClose)
{
        struct sigaction oldAction, action;
        int oldActionResult;
        pid_t newGroup;
        pid_t pid;

        /* Ignore eventually send SIGHUPS on parent exit */
        sigemptyset(&action.sa_mask);
        action.sa_handler = SIG_IGN;
        action.sa_flags = 0;
        oldActionResult = sigaction(SIGHUP, &action, &oldAction);

        pid = fork();
        if (pid == -1) {
                restore_old_sighup(oldActionResult, &oldAction);
                return -1;
        }
        if (pid > 0) {
                // we're the parent - let's exit
                exit(0);
        }

        newGroup = setsid();
        restore_old_sighup(oldActionResult, &oldAction);

        if (newGroup == -1)
                return -1;

        if (!noChangeDir)
                chdir("/");

        if (!noClose) {
                int fd = open("/dev/null", O_RDWR);
                if (fd != -1) {
                        dup2(fd, STDIN_FILENO);
                        dup2(fd, STDOUT_FILENO);
                        dup2(fd, STDERR_FILENO);
                        if (fd > STDERR_FILENO)
                                close(fd);
                }
        }

        return 0;
}