From c285a5ff7665f41684a1f100679b6361ad6383af Mon Sep 17 00:00:00 2001 From: Helmut Grohne Date: Fri, 9 Dec 2016 10:29:55 +0100 Subject: improve sub process handling: return child exit code Wrap the management of the sub process in a new class ForkPty. This reduces the length and number of variables in the main function. Turn it into a context manager to allow closing the masterfd and actually waiting for the forked child (rather than reparenting it to init on exit). This also allows propagating the exit code. Document the new exit semantics. --- tcvt.py | 169 +++++++++++++++++++++++++++++++++++++--------------------------- 1 file changed, 98 insertions(+), 71 deletions(-) (limited to 'tcvt.py') diff --git a/tcvt.py b/tcvt.py index 97df94c..edb102f 100755 --- a/tcvt.py +++ b/tcvt.py @@ -649,6 +649,46 @@ def set_cloexec(fd): flags |= fcntl.FD_CLOEXEC fcntl.fcntl(fd, fcntl.F_SETFD, flags) +class ExecutionError(Exception): + pass + +class ForkPty(object): + def __init__(self, argv, environ={}): + self.argv = argv + self.environ = environ + self.pid = -1 + self.masterfd = -1 + self.exitcode = 255 + + def __enter__(self): + assert self.pid == -1 + assert self.masterfd == -1 + errpiper, errpipew = os.pipe() + set_cloexec(errpipew) + self.pid, self.masterfd = pty.fork() + if self.pid == 0: # child + os.close(errpiper) + os.environ.update(self.environ) + try: + os.execvp(self.argv[0], self.argv) + except OSError as err: + os.write(errpipew, "exec failed: %s" % (err,)) + sys.exit(255) + + os.close(errpipew) + data = os.read(errpiper, 1024) + os.close(errpiper) + if data: + raise ExecutionError(data) + + return self.masterfd + + def __exit__(self, *_): + os.close(self.masterfd) + status = os.waitpid(self.pid, 0)[1] + if status & 0xff == 0: # not killed by a signal + self.exitcode = status >> 8 + def main(): parser = optparse.OptionParser() parser.disable_interspersed_args() @@ -660,79 +700,66 @@ def main(): options, args = parser.parse_args() keymapping, acsc = compute_keymap(symbolic_keymapping) - errpiper, errpipew = os.pipe() - set_cloexec(errpipew) - pid, masterfd = pty.fork() - if pid == 0: # child - os.close(errpiper) - os.environ["TERM"] = "ansi" - try: - if len(args) < 1: - os.execvp(os.environ["SHELL"], [os.environ["SHELL"]]) - else: - os.execvp(args[0], args) - except OSError as err: - os.write(errpipew, "exec failed: %s" % (err,)) - sys.exit(1) - - os.close(errpipew) - data = os.read(errpiper, 1024) - os.close(errpiper) - if data: - print(data) - sys.exit(1) - - with Terminal(acsc, options.columns, reverse=options.reverse) as t: - t.resizepty(masterfd) - refreshpending = None - while True: - try: - res, _, _ = select.select([0, masterfd], [], [], - refreshpending and 0) - except select.error as err: - if err.args[0] == errno.EINTR: - t.resized() - t.resizepty(masterfd) - continue - raise - if 0 in res: + process = ForkPty(args or [os.environ["SHELL"]], dict(TERM="ansi")) + try: + with process as masterfd: + with Terminal(acsc, options.columns, reverse=options.reverse) as t: + t.resizepty(masterfd) + refreshpending = None while True: - key = t.realscreen.getch() - if key == -1: - break - if key == 0xb3: - t.switchmode() - t.resizepty(masterfd) - elif key in keymapping: - os.write(masterfd, keymapping[key]) - elif key <= 0xff: - os.write(masterfd, struct.pack("B", key)) - else: - if "TCVT_DEVEL" in os.environ: - raise ValueError("getch returned %d" % key) - elif masterfd in res: - try: - data = os.read(masterfd, 1024) - except OSError: - break - if not data: - break - for char in bytearray(data): - if "TCVT_DEVEL" in os.environ: - t.feed(char) - else: + try: + res, _, _ = select.select([0, masterfd], [], [], + refreshpending and 0) + except select.error as err: + if err.args[0] == errno.EINTR: + t.resized() + t.resizepty(masterfd) + continue + raise + if 0 in res: + while True: + key = t.realscreen.getch() + if key == -1: + break + if key == 0xb3: + t.switchmode() + t.resizepty(masterfd) + elif key in keymapping: + os.write(masterfd, keymapping[key]) + elif key <= 0xff: + os.write(masterfd, struct.pack("B", key)) + else: + if "TCVT_DEVEL" in os.environ: + raise ValueError("getch returned %d" % key) + elif masterfd in res: try: - t.feed(char) - except ValueError: - t.feed_reset() - if refreshpending is None: - refreshpending = time.time() + 0.1 - elif refreshpending is not None: - t.screen.refresh() - refreshpending = None - if refreshpending is not None and refreshpending < time.time(): - t.screen.refresh() - refreshpending = None + data = os.read(masterfd, 1024) + except OSError: + break + if not data: + break + for char in bytearray(data): + if "TCVT_DEVEL" in os.environ: + t.feed(char) + else: + try: + t.feed(char) + except ValueError: + t.feed_reset() + if refreshpending is None: + refreshpending = time.time() + 0.1 + elif refreshpending is not None: + t.screen.refresh() + refreshpending = None + if refreshpending is not None and \ + refreshpending < time.time(): + t.screen.refresh() + refreshpending = None + except ExecutionError as err: + print(str(err)) + sys.exit(255) + else: + sys.exit(process.exitcode) if __name__ == '__main__': main() -- cgit v1.2.3