workloads: port shellscript workload from WA2

Port shellscript workload that allows running an arbitrary shellscript
as a WA workload from WA2.

wa/workloads/shellscript/__init__.py

@@ -0,0 +1,70 @@
+#    Copyright 2014-2017 ARM Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# pylint: disable=E1101,W0201,E0203
+
+import os
+
+from wa import Workload, Parameter
+from wa.framework.exception import ConfigError, WorkloadError
+
+
+class ShellScript(Workload):
+
+    name = 'shellscript'
+    description = """
+    Runs an arbitrary shellscript on the target.
+
+    """
+
+    parameters = [
+        Parameter('script_file', mandatory=True,
+                  description='''
+                  The path (on the host) to the shell script file. This must be
+                  an absolute path (though it may contain ~).
+                  '''),
+        Parameter('argstring', default='',
+                  description='A string that should contain arguments passed to the script.'),
+        Parameter('as_root', kind=bool, default=False,
+                  description='Specify whether the script should be run as root.'),
+        Parameter('timeout', kind=int, default=60,
+                  description='Timeout, in seconds, for the script run time.'),
+    ]
+
+    def initialize(self, context):
+        if self.as_root and not self.target.is_rooted:
+            raise WorkloadError('Cannot run script as root -- target appears to be unrooted.')
+
+        self.script_file = os.path.expanduser(self.script_file)
+        if not os.path.isfile(self.script_file):
+            raise ConfigError('Can\'t access file (is the path correct?): {}'.format(self.script_file))
+        self.output = None
+        self.command = None
+        self.on_target_script_file = None
+
+    def setup(self, context):
+        self.on_target_script_file = self.target.get_workpath(os.path.basename(self.script_file))
+        self.target.push(self.script_file, self.on_target_script_file)
+        self.command = 'sh {} {}'.format(self.on_target_script_file, self.argstring)
+
+    def run(self, context):
+        self.output = self.target.execute(self.command, timeout=self.timeout, as_root=self.as_root)
+
+    def extract_results(self, context):
+        with open(os.path.join(context.output_directory, 'output.txt'), 'w') as wfh:
+            wfh.write(self.output)
+
+    def teardown(self, context):
+        self.target.remove(self.on_target_script_file)