warden_filer.py 文件源码

def daemonize(
        work_dir = None, chroot_dir = None,
        umask = None, uid = None, gid = None,
        pidfile = None, files_preserve = [], signals = {}):
    # Dirs, limits, users
    if chroot_dir is not None:
        os.chdir(chroot_dir)
        os.chroot(chroot_dir)
    if umask is not None:
        os.umask(umask)
    if work_dir is not None:
        os.chdir(work_dir)
    if gid is not None:
        os.setgid(gid)
    if uid is not None:
        os.setuid(uid)
    # Doublefork, split session
    if os.fork()>0:
        os._exit(0)
    os.setsid()
    if os.fork()>0:
        os._exit(0)
    # Setup signal handlers
    for (signum, handler) in signals.items():
        signal.signal(signum, handler)
    # Close descriptors
    descr_preserve = set(f.fileno() for f in files_preserve)
    maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1]
    if maxfd==resource.RLIM_INFINITY:
        maxfd = 65535
    for fd in range(maxfd, 3, -1):  # 3 means omit stdin, stdout, stderr
        if fd not in descr_preserve:
            try:
                os.close(fd)
            except Exception:
                pass
    # Redirect stdin, stdout, stderr to /dev/null
    devnull = os.open(os.devnull, os.O_RDWR)
    for fd in range(3):
        os.dup2(devnull, fd)
    # PID file
    if pidfile is not None:
        pidd = os.open(pidfile, os.O_RDWR|os.O_CREAT|os.O_EXCL|os.O_TRUNC)
        os.write(pidd, str(os.getpid())+"\n")
        os.close(pidd)
        # Define and setup atexit closure
        @atexit.register
        def unlink_pid():
            try:
                os.unlink(pidfile)
            except Exception:
                pass