shell.py revision effb81e5f8246d0db0270817048dc992db66e9fb 
1# Copyright 2013 The Chromium Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5"""A module for the shell command."""
6
7import os
8import tempfile
9
10import cr
11
12
13class ShellCommand(cr.Command):
14  """The implementation of the shell command.
15
16  The shell command is the escape hatch that lets user run any program in the
17  same environment that cr would use if it were running it.
18  """
19
20  def __init__(self):
21    super(ShellCommand, self).__init__()
22    self.help = 'Launch a shell'
23    self.description = ("""
24        If no arguments are present, this launches an interactive system
25        shell (ie bash) with the environment modified to that used for the
26        build systems.
27        If any arguments are present, they are used as a command line to run
28        in that shell.
29        This allows you to run commands that are not yet available natively
30        in cr.
31        """)
32
33  def AddArguments(self, subparsers):
34    parser = super(ShellCommand, self).AddArguments(subparsers)
35    self.ConsumeArgs(parser, 'the shell')
36    return parser
37
38  def Run(self):
39    if cr.context.remains:
40      cr.Host.Shell(*cr.context.remains)
41      return
42    # If we get here, we are trying to launch an interactive shell
43    shell = os.environ.get('SHELL', None)
44    if shell is None:
45      print 'Don\'t know how to run a shell on this system'
46    elif shell.endswith('bash'):
47      ps1 = '[CR] ' + os.environ.get('PS1', '')
48      with tempfile.NamedTemporaryFile() as rcfile:
49        rcfile.write('source ~/.bashrc\nPS1="'+ps1+'"')
50        rcfile.flush()
51        cr.Host.Execute(shell, '--rcfile', rcfile.name)
52    else:
53      cr.Host.Execute(shell)
54