source: vendor/synergy/current/lib/arch/CArchDaemonUnix.cpp

/*
 * synergy -- mouse and keyboard sharing utility
 * Copyright (C) 2002 Chris Schoeneman
 * 
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file COPYING that should have accompanied this file.
 * 
 * This package is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include "CArchDaemonUnix.h"
#include "XArchUnix.h"
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>

//
// CArchDaemonUnix
//

CArchDaemonUnix::CArchDaemonUnix()
{
        // do nothing
}

CArchDaemonUnix::~CArchDaemonUnix()
{
        // do nothing
}

int
CArchDaemonUnix::daemonize(const char* name, DaemonFunc func)
{
        // fork so shell thinks we're done and so we're not a process
        // group leader
        switch (fork()) {
        case -1:
                // failed
                throw XArchDaemonFailed(new XArchEvalUnix(errno));

        case 0:
                // child
                break;

        default:
                // parent exits
                exit(0);
        }

        // become leader of a new session
        setsid();

        // chdir to root so we don't keep mounted filesystems points busy
        chdir("/");

        // mask off permissions for any but owner
        umask(077);

        // close open files.  we only expect stdin, stdout, stderr to be open.
        close(0);
        close(1);
        close(2);

        // attach file descriptors 0, 1, 2 to /dev/null so inadvertent use
        // of standard I/O safely goes in the bit bucket.
        open("/dev/null", O_RDONLY);
        open("/dev/null", O_RDWR);
        dup(1);

        // invoke function
        return func(1, &name);
}