Victor Stinner | addaaaa | 2020-03-09 23:45:59 +0100 | [diff] [blame] | 1 | """ |
| 2 | Basic subprocess implementation for POSIX which only uses os functions. Only |
| 3 | implement features required by setup.py to build C extension modules when |
| 4 | subprocess is unavailable. setup.py is not used on Windows. |
| 5 | """ |
| 6 | import os |
| 7 | |
| 8 | |
| 9 | # distutils.spawn used by distutils.command.build_ext |
| 10 | # calls subprocess.Popen().wait() |
| 11 | class Popen: |
| 12 | def __init__(self, cmd, env=None): |
| 13 | self._cmd = cmd |
| 14 | self._env = env |
| 15 | self.returncode = None |
| 16 | |
| 17 | def wait(self): |
| 18 | pid = os.fork() |
| 19 | if pid == 0: |
| 20 | # Child process |
| 21 | try: |
| 22 | if self._env is not None: |
| 23 | os.execve(self._cmd[0], self._cmd, self._env) |
| 24 | else: |
| 25 | os.execv(self._cmd[0], self._cmd) |
| 26 | finally: |
| 27 | os._exit(1) |
| 28 | else: |
| 29 | # Parent process |
Victor Stinner | 40bfdb1 | 2020-03-31 23:45:13 +0200 | [diff] [blame] | 30 | _, status = os.waitpid(pid, 0) |
Victor Stinner | 65a796e | 2020-04-01 18:49:29 +0200 | [diff] [blame] | 31 | self.returncode = os.waitstatus_to_exitcode(status) |
Victor Stinner | addaaaa | 2020-03-09 23:45:59 +0100 | [diff] [blame] | 32 | |
| 33 | return self.returncode |
| 34 | |
| 35 | |
| 36 | def _check_cmd(cmd): |
| 37 | # Use regex [a-zA-Z0-9./-]+: reject empty string, space, etc. |
| 38 | safe_chars = [] |
| 39 | for first, last in (("a", "z"), ("A", "Z"), ("0", "9")): |
| 40 | for ch in range(ord(first), ord(last) + 1): |
| 41 | safe_chars.append(chr(ch)) |
| 42 | safe_chars.append("./-") |
| 43 | safe_chars = ''.join(safe_chars) |
| 44 | |
| 45 | if isinstance(cmd, (tuple, list)): |
| 46 | check_strs = cmd |
| 47 | elif isinstance(cmd, str): |
| 48 | check_strs = [cmd] |
| 49 | else: |
| 50 | return False |
| 51 | |
| 52 | for arg in check_strs: |
| 53 | if not isinstance(arg, str): |
| 54 | return False |
| 55 | if not arg: |
| 56 | # reject empty string |
| 57 | return False |
| 58 | for ch in arg: |
| 59 | if ch not in safe_chars: |
| 60 | return False |
| 61 | |
| 62 | return True |
| 63 | |
| 64 | |
| 65 | # _aix_support used by distutil.util calls subprocess.check_output() |
| 66 | def check_output(cmd, **kwargs): |
| 67 | if kwargs: |
| 68 | raise NotImplementedError(repr(kwargs)) |
| 69 | |
| 70 | if not _check_cmd(cmd): |
| 71 | raise ValueError(f"unsupported command: {cmd!r}") |
| 72 | |
| 73 | tmp_filename = "check_output.tmp" |
| 74 | if not isinstance(cmd, str): |
| 75 | cmd = " ".join(cmd) |
| 76 | cmd = f"{cmd} >{tmp_filename}" |
| 77 | |
| 78 | try: |
| 79 | # system() spawns a shell |
| 80 | status = os.system(cmd) |
Victor Stinner | 65a796e | 2020-04-01 18:49:29 +0200 | [diff] [blame] | 81 | exitcode = os.waitstatus_to_exitcode(status) |
Victor Stinner | 40bfdb1 | 2020-03-31 23:45:13 +0200 | [diff] [blame] | 82 | if exitcode: |
| 83 | raise ValueError(f"Command {cmd!r} returned non-zero " |
| 84 | f"exit status {exitcode!r}") |
Victor Stinner | addaaaa | 2020-03-09 23:45:59 +0100 | [diff] [blame] | 85 | |
| 86 | try: |
| 87 | with open(tmp_filename, "rb") as fp: |
| 88 | stdout = fp.read() |
| 89 | except FileNotFoundError: |
| 90 | stdout = b'' |
| 91 | finally: |
| 92 | try: |
| 93 | os.unlink(tmp_filename) |
| 94 | except OSError: |
| 95 | pass |
| 96 | |
| 97 | return stdout |