import fcntl
import os

def close_fds(pass_fds=()):
    try:
        MAXFD = os.sysconf('SC_OPEN_MAX')
    except:
        MAXFD = 256
    for i in range(3, MAXFD):
        if i in pass_fds:
            continue
        try:
            os.close(i)
        except OSError:
            pass

def fcntl_setfd_cloexec(file, bool):
        f = fcntl.fcntl(file, fcntl.F_GETFD)
        if bool: f |= fcntl.FD_CLOEXEC
        else: f &= ~fcntl.FD_CLOEXEC
        fcntl.fcntl(file, fcntl.F_SETFD, f)

def waitstatus_description(st):
        if os.WIFEXITED(st):
                es = os.WEXITSTATUS(st)
                if es: return "exited with nonzero status %i" % es
                else: return "exited"
        elif os.WIFSIGNALED(st):
                s = "died due to signal %i" % os.WTERMSIG(st)
                if os.WCOREDUMP(st): s += " (core dumped)"
                return s
        else:
                return "failed with unexpected wait status %i" % st