Error out in `gclient config` if --name is relative

This helps prevent behavior such as setting '--name .' so that the .gclient
file contains '.' as the name of the solution, and the .gclient file ends
up a sibling of the .git file, rather than a sibling of the git checkout's
containing directory.

R=iannucci@chromium.org, thestig@chromium.org

Review URL: https://codereview.chromium.org/1406053003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@297343 0039d316-1c4b-4281-b951-d872f2087c98

gclient.py

@@ -1886,6 +1886,12 @@ def CMDconfig(parser, args):
     else:
       # specify an alternate relpath for the given URL.
       name = options.name
+      if not os.path.abspath(os.path.join(os.getcwd(), name)).startswith(
+          os.getcwd()):
+        parser.error('Do not pass a relative path for --name.')
+      if any(x in ('..', '.', '/', '\\') for x in name.split(os.sep)):
+        parser.error('Do not include relative path components in --name.')
+
     deps_file = options.deps_file
     safesync_url = ''
     if len(args) > 1: