[feat] Validate and execute commands by subprocess

This commit adds a way to validate and execute commands using an
argument validator. Commands are executed via subprocess.

1 files changed, 54 insertions, 0 deletions

diff --git a/common/src/leap/soledad/common/command.py b/common/src/leap/soledad/common/command.py
new file mode 100644
index 00000000..978cec91
--- /dev/null
+++ b/common/src/leap/soledad/common/command.py
@@ -0,0 +1,54 @@
+# -*- coding: utf-8 -*-
+# command.py
+# Copyright (C) 2015 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+"""
+Utility to sanitize and run shell commands.
+"""
+
+
+import subprocess
+
+
+def exec_validated_cmd(cmd, args, validator=None):
+    """
+    Executes cmd, validating args with validator.
+
+    :param cmd: command.
+    :type dbname: str
+    :param args: arguments.
+    :type args: str
+    :param validator: optional function to validate args
+    :type validator: function
+
+    :return: exit code and stdout or stderr (if code != 0)
+    :rtype: (int, str)
+    """
+    if validator and not validator(args):
+        return 1, "invalid argument"
+    command = cmd.split(' ')
+    command.append(args)
+    try:
+        process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    except OSError, e:
+        return 1, e
+    (out, err) = process.communicate()
+    code = process.wait()
+    if code is not 0:
+        return code, err
+    else:
+        return code, out