spawn.py 文件源码

def _spawn_posix(cmd, search_path=1, verbose=0, dry_run=0):
    log.info(' '.join(cmd))
    if dry_run:
        return
    exec_fn = search_path and os.execvp or os.execv
    pid = os.fork()

    if pid == 0:  # in the child
        try:
            exec_fn(cmd[0], cmd)
        except OSError, e:
            sys.stderr.write("unable to execute %s: %s\n" %
                             (cmd[0], e.strerror))
            os._exit(1)

        sys.stderr.write("unable to execute %s for unknown reasons" % cmd[0])
        os._exit(1)
    else:   # in the parent
        # Loop until the child either exits or is terminated by a signal
        # (ie. keep waiting if it's merely stopped)
        while 1:
            try:
                pid, status = os.waitpid(pid, 0)
            except OSError, exc:
                import errno
                if exc.errno == errno.EINTR:
                    continue
                raise DistutilsExecError, \
                      "command '%s' failed: %s" % (cmd[0], exc[-1])
            if os.WIFSIGNALED(status):
                raise DistutilsExecError, \
                      "command '%s' terminated by signal %d" % \
                      (cmd[0], os.WTERMSIG(status))

            elif os.WIFEXITED(status):
                exit_status = os.WEXITSTATUS(status)
                if exit_status == 0:
                    return   # hey, it succeeded!
                else:
                    raise DistutilsExecError, \
                          "command '%s' failed with exit status %d" % \
                          (cmd[0], exit_status)

            elif os.WIFSTOPPED(status):
                continue

            else:
                raise DistutilsExecError, \
                      "unknown error executing '%s': termination status %d" % \
                      (cmd[0], status)