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# Copyright 2018 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import logging
import os
import subprocess
import threading
from common import SubprocessCallWithTimeout
_SSH = ['ssh']
_SCP = ['scp', '-C'] # Use gzip compression.
_SSH_LOGGER = logging.getLogger('ssh')
COPY_TO_TARGET = 0
COPY_FROM_TARGET = 1
def _IsLinkLocalIPv6(hostname):
return hostname.startswith('fe80::')
def _EscapeIfIPv6Address(address):
if ':' in address:
return '[' + address + ']'
else:
return address
class CommandRunner(object):
"""Helper class used to execute commands on a remote host over SSH."""
def __init__(self, config_path, host, port):
"""Creates a CommandRunner that connects to the specified |host| and |port|
using the ssh config at the specified |config_path|.
config_path: Full path to SSH configuration.
host: The hostname or IP address of the remote host.
port: The port to connect to."""
self._config_path = config_path
self._host = host
self._port = port
def _GetSshCommandLinePrefix(self):
cmd_prefix = _SSH + ['-F', self._config_path, self._host]
if self._port:
cmd_prefix += ['-p', str(self._port)]
return cmd_prefix
def RunCommand(self, command, silent, timeout_secs=None):
"""Executes an SSH command on the remote host and blocks until completion.
command: A list of strings containing the command and its arguments.
silent: If true, suppresses all output from 'ssh'.
timeout_secs: If set, limits the amount of time that |command| may run.
Commands which exceed the timeout are killed.
Returns the exit code from the remote command."""
ssh_command = self._GetSshCommandLinePrefix() + command
logging.warning(ssh_command)
_SSH_LOGGER.debug('ssh exec: ' + ' '.join(ssh_command))
retval, _, _ = SubprocessCallWithTimeout(ssh_command, silent, timeout_secs)
return retval
def RunCommandPiped(self, command, stdout, stderr, ssh_args = None, **kwargs):
"""Executes an SSH command on the remote host and returns a process object
with access to the command's stdio streams. Does not block.
command: A list of strings containing the command and its arguments.
stdout: subprocess stdout. Must not be None.
stderr: subprocess stderr. Must not be None.
ssh_args: Arguments that will be passed to SSH.
kwargs: A dictionary of parameters to be passed to subprocess.Popen().
The parameters can be used to override stdin and stdout, for
example.
Returns a Popen object for the command."""
if not stdout or not stderr:
raise Exception('Stdout/stderr must be specified explicitly')
if not ssh_args:
ssh_args = []
ssh_command = self._GetSshCommandLinePrefix() + ssh_args + ['--'] + command
logging.warning(ssh_command)
_SSH_LOGGER.debug(' '.join(ssh_command))
return subprocess.Popen(ssh_command, stdout=stdout, stderr=stderr, **kwargs)
def RunScp(self, sources, dest, direction, recursive=False):
"""Copies a file to or from a remote host using SCP and blocks until
completion.
sources: Paths of the files to be copied.
dest: The path that |source| will be copied to.
direction: Indicates whether the file should be copied to
or from the remote side.
Valid values are COPY_TO_TARGET or COPY_FROM_TARGET.
recursive: If true, performs a recursive copy.
Function will raise an assertion if a failure occurred."""
scp_command = _SCP[:]
if _SSH_LOGGER.getEffectiveLevel() == logging.DEBUG:
scp_command.append('-v')
if recursive:
scp_command.append('-r')
host = _EscapeIfIPv6Address(self._host)
if direction == COPY_TO_TARGET:
dest = "%s:%s" % (host, dest)
else:
sources = ["%s:%s" % (host, source) for source in sources]
scp_command += ['-F', self._config_path]
if self._port:
scp_command += ['-P', str(self._port)]
scp_command += sources
scp_command += [dest]
_SSH_LOGGER.debug(' '.join(scp_command))
try:
scp_output = subprocess.check_output(scp_command,
stderr=subprocess.STDOUT)
except subprocess.CalledProcessError as error:
_SSH_LOGGER.info(error.output)
raise