util,stdlib: Add util/md5.py

This is a useful script for quickly checking the hash values of
resources. Since this uses the same function as the downloader, using
this utility ensures the values are identical to that found in
resources.json (i.e., what the downloader checks against to see if a
resource has changed).

Change-Id: I37f39cb8fd2c92725d956170b3656cbfb4480ce6
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/58850
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/util/md5.py b/util/md5.py
new file mode 100644
index 0000000..333f714
--- /dev/null
+++ b/util/md5.py
@@ -0,0 +1,51 @@
+# Copyright (c) 2022 The Regents of the University of California
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import argparse
+from pathlib import Path
+from gem5.resources.md5_utils import md5_file, md5_dir
+
+parser = argparse.ArgumentParser(
+    description="A utility to determine the md5 hash of files and "
+    "directories. These will correspond the hash values recorded "
+    "for gem5-resources entries."
+)
+
+parser.add_argument("path", type=str, help="The path to the file/directory.")
+
+args = parser.parse_args()
+
+path = Path(args.path)
+
+if path.is_file():
+    print(md5_file(path))
+    exit(0)
+elif path.is_dir():
+    print(md5_dir(path))
+    exit(0)
+
+print("Input path is neither a file nor directory.")
+exit(1)