source: asp3_tinet_ecnl_arm/trunk/musl-1.1.18/src/legacy/daemon.c@ 352

#define _GNU_SOURCE
#include <fcntl.h>
#include <unistd.h>

int daemon(int nochdir, int noclose)
{
        if (!nochdir && chdir("/"))
                return -1;
        if (!noclose) {
                int fd, failed = 0;
                if ((fd = open("/dev/null", O_RDWR)) < 0) return -1;
                if (dup2(fd, 0) < 0 || dup2(fd, 1) < 0 || dup2(fd, 2) < 0)
                        failed++;
                if (fd > 2) close(fd);
                if (failed) return -1;
        }

        switch(fork()) {
        case 0: break;
        case -1: return -1;
        default: _exit(0);
        }

        if (setsid() < 0) return -1;

        switch(fork()) {
        case 0: break;
        case -1: return -1;
        default: _exit(0);
        }

        return 0;
}