• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1# SPDX-License-Identifier: GPL-2.0+
2# Copyright (c) 2011 The Chromium OS Authors.
3#
4
5import os
6import cros_subprocess
7
8"""Shell command ease-ups for Python."""
9
10class CommandResult:
11    """A class which captures the result of executing a command.
12
13    Members:
14        stdout: stdout obtained from command, as a string
15        stderr: stderr obtained from command, as a string
16        return_code: Return code from command
17        exception: Exception received, or None if all ok
18    """
19    def __init__(self):
20        self.stdout = None
21        self.stderr = None
22        self.combined = None
23        self.return_code = None
24        self.exception = None
25
26    def __init__(self, stdout='', stderr='', combined='', return_code=0,
27                 exception=None):
28        self.stdout = stdout
29        self.stderr = stderr
30        self.combined = combined
31        self.return_code = return_code
32        self.exception = exception
33
34
35# This permits interception of RunPipe for test purposes. If it is set to
36# a function, then that function is called with the pipe list being
37# executed. Otherwise, it is assumed to be a CommandResult object, and is
38# returned as the result for every RunPipe() call.
39# When this value is None, commands are executed as normal.
40test_result = None
41
42def RunPipe(pipe_list, infile=None, outfile=None,
43            capture=False, capture_stderr=False, oneline=False,
44            raise_on_error=True, cwd=None, **kwargs):
45    """
46    Perform a command pipeline, with optional input/output filenames.
47
48    Args:
49        pipe_list: List of command lines to execute. Each command line is
50            piped into the next, and is itself a list of strings. For
51            example [ ['ls', '.git'] ['wc'] ] will pipe the output of
52            'ls .git' into 'wc'.
53        infile: File to provide stdin to the pipeline
54        outfile: File to store stdout
55        capture: True to capture output
56        capture_stderr: True to capture stderr
57        oneline: True to strip newline chars from output
58        kwargs: Additional keyword arguments to cros_subprocess.Popen()
59    Returns:
60        CommandResult object
61    """
62    if test_result:
63        if hasattr(test_result, '__call__'):
64            return test_result(pipe_list=pipe_list)
65        return test_result
66    result = CommandResult()
67    last_pipe = None
68    pipeline = list(pipe_list)
69    user_pipestr =  '|'.join([' '.join(pipe) for pipe in pipe_list])
70    kwargs['stdout'] = None
71    kwargs['stderr'] = None
72    while pipeline:
73        cmd = pipeline.pop(0)
74        if last_pipe is not None:
75            kwargs['stdin'] = last_pipe.stdout
76        elif infile:
77            kwargs['stdin'] = open(infile, 'rb')
78        if pipeline or capture:
79            kwargs['stdout'] = cros_subprocess.PIPE
80        elif outfile:
81            kwargs['stdout'] = open(outfile, 'wb')
82        if capture_stderr:
83            kwargs['stderr'] = cros_subprocess.PIPE
84
85        try:
86            last_pipe = cros_subprocess.Popen(cmd, cwd=cwd, **kwargs)
87        except Exception as err:
88            result.exception = err
89            if raise_on_error:
90                raise Exception("Error running '%s': %s" % (user_pipestr, str))
91            result.return_code = 255
92            return result
93
94    if capture:
95        result.stdout, result.stderr, result.combined = (
96                last_pipe.CommunicateFilter(None))
97        if result.stdout and oneline:
98            result.output = result.stdout.rstrip('\r\n')
99        result.return_code = last_pipe.wait()
100    else:
101        result.return_code = os.waitpid(last_pipe.pid, 0)[1]
102    if raise_on_error and result.return_code:
103        raise Exception("Error running '%s'" % user_pipestr)
104    return result
105
106def Output(*cmd, **kwargs):
107    raise_on_error = kwargs.get('raise_on_error', True)
108    return RunPipe([cmd], capture=True, raise_on_error=raise_on_error).stdout
109
110def OutputOneLine(*cmd, **kwargs):
111    raise_on_error = kwargs.pop('raise_on_error', True)
112    return (RunPipe([cmd], capture=True, oneline=True,
113            raise_on_error=raise_on_error,
114            **kwargs).stdout.strip())
115
116def Run(*cmd, **kwargs):
117    return RunPipe([cmd], **kwargs).stdout
118
119def RunList(cmd):
120    return RunPipe([cmd], capture=True).stdout
121
122def StopAll():
123    cros_subprocess.stay_alive = False
124