# OSError, 1 means some other error. errpipe_read, errpipe_write = os.pipe() self._set_cloexec_flag(errpipe_write) self.pid = os.fork() self._child_created = True if self.pid == 0: # Child try: # Close parent's pipe ends if p2cwrite: os.close(p2cwrite) if c2pread: os.close(c2pread) if errread: os.close(errread) os.close(errpipe_read) # Dup fds for child if p2cread: os.dup2(p2cread, 0) if c2pwrite: os.dup2(c2pwrite, 1) if errwrite: os.dup2(errwrite, 2) # Close pipe fds. Make sure we don't close the same # fd more than once, or standard fds. if p2cread and p2cread not in (0,): os.close(p2cread) if c2pwrite and c2pwrite not in (p2cread, 1): os.close(c2pwrite) if errwrite and errwrite not in (p2cread, c2pwrite, 2): os.close(errwrite) # Close all other fds, if asked for if close_fds: self._close_fds(but=errpipe_write) if cwd is not None: os.chdir(cwd) if preexec_fn: apply(preexec_fn) if env is None: os.execvp(executable, args) else: os.execvpe(executable, args, env) except: exc_type, exc_value, tb = sys.exc_info() # Save the traceback and attach it to the exception object exc_lines = traceback.format_exception(exc_type, exc_value, tb) exc_value.child_traceback = ''.join(exc_lines) os.write(errpipe_write, pickle.dumps(exc_value)) # This exitcode won't be reported to applications, so it # really doesn't matter what we return. os._exit(255) # Parent os.close(errpipe_write) if p2cread and p2cwrite: os.close(p2cread) if c2pwrite and c2pread: os.close(c2pwrite) if errwrite and errread: os.close(errwrite) # Wait for exec to fail or succeed; possibly raising exception data = os.read(errpipe_read, 1048576) # Exceptions limited to 1 MB os.close(errpipe_read) if data != "": os.waitpid(self.pid, 0) child_exception = pickle.loads(data) raise child_exception def _handle_exitstatus(self, sts): if os.WIFSIGNALED(sts): self.returncode = -os.WTERMSIG(sts) elif os.WIFEXITED(sts): self.returncode = os.WEXITSTATUS(sts) else: # Should never happen raise RuntimeError("Unknown child exit status!") def poll(self, _deadstate=None): """Check if child process has terminated. Returns returncode attribute.""" if self.returncode is None: try: pid, sts = os.waitpid(self.pid, os.WNOHANG) if pid == self.pid: self._handle_exitstatus(sts) except os.error: if _deadstate is not None: self.returncode = _deadstate return self.returncode def wait(self): """Wait for child process to terminate. Returns returncode attribute.""" if self.returncode is None: pid, sts = os.waitpid(self.pid, 0) self._handle_exitstatus(sts) return self.returncode def _communicate(self, input): read_set = [] write_set = [] stdout = None # Return stderr = None # Return if self.stdin: # Flush stdio buffer. This might block, if the user has # been writing to .stdin in an uncontrolled fashion. self.stdin.flush() if input: write_set.append(self.stdin) else: self.stdin.close() if self.stdout: read_set.append(self.stdout) stdout = [] if self.stderr: read_set.append(self.stderr) stderr = [] input_offset = 0 while read_set or write_set: rlist, wlist, xlist = select.select(read_set, write_set, []) if self.stdin in wlist: # When select has indicated that the file is writable, # we can write up to PIPE_BUF bytes without risk # blocking. POSIX defines PIPE_BUF >= 512 bytes_written = os.write(self.stdin.fileno(), buffer(input, input_offset, 512)) input_offset += bytes_written if input_offset >= len(input): self.stdin.close() write_set.remove(self.stdin) if self.stdout in rlist: data = os.read(self.stdout.fileno(), 1024) if data == "": self.stdout.close() read_set.remove(self.stdout) stdout.append(data) if self.stderr in rlist: data = os.read(self.stderr.fileno(), 1024) if data == "": self.stderr.close() read_set.remove(self.stderr) stderr.append(data) # All data exchanged. Translate lists into strings. if stdout is not None: stdout = ''.join(stdout) if stderr is not None: stderr = ''.join(stderr) # Translate newlines, if requested. We cannot let the file # object do the translation: It is based on stdio, which is # impossible to combine with select (unless forcing no # buffering). if self.universal_newlines and hasattr(file, 'newlines'): if stdout: stdout = self._translate_newlines(stdout) if stderr: stderr = self._translate_newlines(stderr) self.wait() return (stdout, stderr) def _demo_posix(): # # Example 1: Simple redirection: Get process list # plist = Popen(["ps"], stdout=PIPE).communicate()[0] print "Process list:" print plist # # Example 2: Change uid before executing child # if os.getuid() == 0: p = Popen(["id"], preexec_fn=lambda: os.setuid(100)) p.wait() # # Example 3: Connecting several subprocesses # print "Looking for 'hda'..." p1 = Popen(["dmesg"], stdout=PIPE) p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE) print repr(p2.communicate()[0]) # # Example 4: Catch execution error # print print "Trying a weird file..." try: print Popen(["/this/path/does/not/exist"]).communicate() except OSError, e: if e.errno == errno.ENOENT: print "The file didn't exist. I thought so..." print "Child traceback:" print e.child_traceback else: print "Error", e.errno else: print >>sys.stderr, "Gosh. No error." def _demo_windows(): # # Example 1: Connecting several subprocesses # print "Looking for 'PROMPT' in set output..." p1 = Popen("set", stdout=PIPE, shell=True) p2 = Popen('find "PROMPT"', stdin=p1.stdout, stdout=PIPE) print repr(p2.communicate()[0]) # # Example 2: Simple execution of program # print "Executing calc..." p = Popen("calc") p.wait() if __name__ == "__main__": if mswindows: _demo_windows() else: _demo_posix()Lines 1001–1246 of 1246. Previous lines
# OSError, 1 means some other error. errpipe_read, errpipe_write = os.pipe() self._set_cloexec_flag(errpipe_write) self.pid = os.fork() self._child_created = True if self.pid == 0: # Child try: # Close parent's pipe ends if p2cwrite: os.close(p2cwrite) if c2pread: os.close(c2pread) if errread: os.close(errread) os.close(errpipe_read) # Dup fds for child if p2cread: os.dup2(p2cread, 0) if c2pwrite: os.dup2(c2pwrite, 1) if errwrite: os.dup2(errwrite, 2) # Close pipe fds. Make sure we don't close the same # fd more than once, or standard fds. if p2cread and p2cread not in (0,): os.close(p2cread) if c2pwrite and c2pwrite not in (p2cread, 1): os.close(c2pwrite) if errwrite and errwrite not in (p2cread, c2pwrite, 2): os.close(errwrite) # Close all other fds, if asked for if close_fds: self._close_fds(but=errpipe_write) if cwd is not None: os.chdir(cwd) if preexec_fn: apply(preexec_fn) if env is None: os.execvp(executable, args) else: os.execvpe(executable, args, env) except: exc_type, exc_value, tb = sys.exc_info() # Save the traceback and attach it to the exception object exc_lines = traceback.format_exception(exc_type, exc_value, tb) exc_value.child_traceback = ''.join(exc_lines) os.write(errpipe_write, pickle.dumps(exc_value)) # This exitcode won't be reported to applications, so it # really doesn't matter what we return. os._exit(255) # Parent os.close(errpipe_write) if p2cread and p2cwrite: os.close(p2cread) if c2pwrite and c2pread: os.close(c2pwrite) if errwrite and errread: os.close(errwrite) # Wait for exec to fail or succeed; possibly raising exception data = os.read(errpipe_read, 1048576) # Exceptions limited to 1 MB os.close(errpipe_read) if data != "": os.waitpid(self.pid, 0) child_exception = pickle.loads(data) raise child_exception def _handle_exitstatus(self, sts): if os.WIFSIGNALED(sts): self.returncode = -os.WTERMSIG(sts) elif os.WIFEXITED(sts): self.returncode = os.WEXITSTATUS(sts) else: # Should never happen raise RuntimeError("Unknown child exit status!") def poll(self, _deadstate=None): """Check if child process has terminated. Returns returncode attribute.""" if self.returncode is None: try: pid, sts = os.waitpid(self.pid, os.WNOHANG) if pid == self.pid: self._handle_exitstatus(sts) except os.error: if _deadstate is not None: self.returncode = _deadstate return self.returncode def wait(self): """Wait for child process to terminate. Returns returncode attribute.""" if self.returncode is None: pid, sts = os.waitpid(self.pid, 0) self._handle_exitstatus(sts) return self.returncode def _communicate(self, input): read_set = [] write_set = [] stdout = None # Return stderr = None # Return if self.stdin: # Flush stdio buffer. This might block, if the user has # been writing to .stdin in an uncontrolled fashion. self.stdin.flush() if input: write_set.append(self.stdin) else: self.stdin.close() if self.stdout: read_set.append(self.stdout) stdout = [] if self.stderr: read_set.append(self.stderr) stderr = [] input_offset = 0 while read_set or write_set: rlist, wlist, xlist = select.select(read_set, write_set, []) if self.stdin in wlist: # When select has indicated that the file is writable, # we can write up to PIPE_BUF bytes without risk # blocking. POSIX defines PIPE_BUF >= 512 bytes_written = os.write(self.stdin.fileno(), buffer(input, input_offset, 512)) input_offset += bytes_written if input_offset >= len(input): self.stdin.close() write_set.remove(self.stdin) if self.stdout in rlist: data = os.read(self.stdout.fileno(), 1024) if data == "": self.stdout.close() read_set.remove(self.stdout) stdout.append(data) if self.stderr in rlist: data = os.read(self.stderr.fileno(), 1024) if data == "": self.stderr.close() read_set.remove(self.stderr) stderr.append(data) # All data exchanged. Translate lists into strings. if stdout is not None: stdout = ''.join(stdout) if stderr is not None: stderr = ''.join(stderr) # Translate newlines, if requested. We cannot let the file # object do the translation: It is based on stdio, which is # impossible to combine with select (unless forcing no # buffering). if self.universal_newlines and hasattr(file, 'newlines'): if stdout: stdout = self._translate_newlines(stdout) if stderr: stderr = self._translate_newlines(stderr) self.wait() return (stdout, stderr) def _demo_posix(): # # Example 1: Simple redirection: Get process list # plist = Popen(["ps"], stdout=PIPE).communicate()[0] print "Process list:" print plist # # Example 2: Change uid before executing child # if os.getuid() == 0: p = Popen(["id"], preexec_fn=lambda: os.setuid(100)) p.wait() # # Example 3: Connecting several subprocesses # print "Looking for 'hda'..." p1 = Popen(["dmesg"], stdout=PIPE) p2 = Popen(["grep", "hda"], stdin=p1.stdout, stdout=PIPE) print repr(p2.communicate()[0]) # # Example 4: Catch execution error # print print "Trying a weird file..." try: print Popen(["/this/path/does/not/exist"]).communicate() except OSError, e: if e.errno == errno.ENOENT: print "The file didn't exist. I thought so..." print "Child traceback:" print e.child_traceback else: print "Error", e.errno else: print >>sys.stderr, "Gosh. No error." def _demo_windows(): # # Example 1: Connecting several subprocesses # print "Looking for 'PROMPT' in set output..." p1 = Popen("set", stdout=PIPE, shell=True) p2 = Popen('find "PROMPT"', stdin=p1.stdout, stdout=PIPE) print repr(p2.communicate()[0]) # # Example 2: Simple execution of program # print "Executing calc..." p = Popen("calc") p.wait() if __name__ == "__main__": if mswindows: _demo_windows() else: _demo_posix()