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      1 # Copyright 2014 The Chromium OS 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 import os
      6 
      7 from autotest_lib.client.bin import utils
      8 from autotest_lib.client.common_lib import error
      9 
     10 
     11 def get_install_path(filename, host=None):
     12     """
     13     Checks if a file exists on a remote machine in one of several paths.
     14 
     15     @param filename String name of the file to check for existence.
     16     @param host Host object representing the remote machine.
     17     @return String full path of installed file, or None if not found.
     18 
     19     """
     20     run = utils.run
     21     if host is not None:
     22         run = host.run
     23     PATHS = ['/bin',
     24              '/sbin',
     25              '/system/bin',
     26              '/system/xbin',
     27              '/usr/bin',
     28              '/usr/sbin',
     29              '/usr/local/bin',
     30              '/usr/local/sbin']
     31     glob_list = [os.path.join(path, filename) for path in PATHS]
     32     # Some hosts have poor support for which.  Sometimes none.
     33     # Others have shells that can't perform advanced globbing.
     34     result = host.run('ls %s 2> /dev/null' % ' '.join(glob_list),
     35                       ignore_status=True)
     36     found_path = result.stdout.split('\n')[0].strip()
     37     return found_path or None
     38 
     39 
     40 def must_be_installed(cmd, host=None):
     41     """
     42     Asserts that cmd is installed on a remote machine at some path and raises
     43     an exception if this is not the case.
     44 
     45     @param cmd String name of the command to check for existence.
     46     @param host Host object representing the remote machine.
     47     @return String full path of cmd on success.  Error raised on failure.
     48 
     49     """
     50     run = utils.run
     51     if host is not None:
     52         run = host.run
     53     if run('ls %s >/dev/null 2>&1' % cmd,
     54            ignore_status=True).exit_status == 0:
     55         return cmd
     56 
     57     # Hunt for the equivalent file in a bunch of places.
     58     cmd_base = os.path.basename(cmd)
     59     alternate_path = get_install_path(cmd_base, host=host)
     60     if alternate_path:
     61         return alternate_path
     62 
     63     error_msg = 'Unable to find %s' % cmd
     64     if host is not None:
     65         error_msg += ' on %s' % host.hostname
     66     raise error.TestError(error_msg)
     67