Initial version of the abi monitoring utilities

Add a generic abitool implementation that is capable of translating
common abi operations like dumping and diffing to concrete tool
implementation.

Also add the cmd line utilities `diff_abi` and `dump_abi`.

Bug: 111449103
Co-authored-by: Jayant Chowdhary <jchowdhary@google.com>
Change-Id: I1c4dedb96f4806ea58cf11786d0e7464e26f3059
Signed-off-by: Matthias Maennich <maennich@google.com>

5 files changed, 190 insertions, 0 deletions

diff --git a/abi/.gitignore b/abi/.gitignore
index 3438f57..6ddc8a7 100644
--- a/abi/.gitignore
+++ b/abi/.gitignore
@@ -1 +1,3 @@
 abigail-*
+*.pyc
+__pycache__
diff --git a/abi/README.md b/abi/README.md
index 4b8544a..23541b7 100644
--- a/abi/README.md
+++ b/abi/README.md
@@ -18,3 +18,23 @@ the local `${PATH}` to be used by the remaining utilities.
 
 You can skip this step if your host system provides a suitable version of the
 libabigail tooling including the binaries `abidw` and `abidiff`.
+
+
+Creating ABI dumps from kernel trees
+------------------------------------
+Provided a linux kernel tree with built vmlinux and kernel modules, the tool
+`dump_abi` creates an ABI representation using the selected abi tool. As of now
+there is only one option: 'libabigail' (default). A sample invocation looks as
+follows:
+  $ dump_abi --linux-tree path/to/out --out-file /path/to/abidump.out
+
+
+Comparing ABI dumps
+-------------------
+ABI dumps created by `dump_abi` can be compared with `diff_abi`. Ensure to use
+the same abi-tool for `dump_abi` and `diff_abi`. A sample invocation looks as
+follows:
+  $ diff_abi --baseline dump1.out --new dump2.out --report report.out
+
+The report created is tool specific, but generally lists ABI changes detected
+that affect the Kernel's module interface.
diff --git a/abi/abitool.py b/abi/abitool.py
new file mode 100644
index 0000000..9491c3f
--- /dev/null
+++ b/abi/abitool.py
@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2019 The Android Open Source Project
+#
+# 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.
+#
+
+import subprocess
+import logging
+
+log = logging.getLogger(__name__)
+
+class AbiTool(object):
+    """ Base class for different kinds of abi analysis tools"""
+    def dump_kernel_abi(self, linux_tree, dump_path):
+        raise NotImplementedError()
+
+    def diff_abi(self, old_dump, new_dump, diff_report):
+        raise NotImplementedError()
+
+    def name(self):
+        raise NotImplementedError()
+
+class Libabigail(AbiTool):
+    """" Concrete AbiTool implementation for libabigail """
+    def dump_kernel_abi(self, linux_tree, dump_path):
+        dump_abi_cmd = ['abidw',
+                        '--linux-tree',
+                        linux_tree,
+                        '--out-file',
+                        dump_path]
+        subprocess.check_call(dump_abi_cmd)
+
+    def diff_abi(self, old_dump, new_dump, diff_report):
+        log.info('libabigail diffing: {} and {} at {}'.format(old_dump,
+                                                                new_dump,
+                                                                diff_report))
+        diff_abi_cmd = ['abidiff',
+                        '--impacted-interfaces',
+                        '--leaf-changes-only',
+                        '--dump-diff-tree',
+                        old_dump,
+                        new_dump]
+
+        with open(diff_report, 'w') as out:
+            try:
+                subprocess.check_call(diff_abi_cmd, stdout=out, stderr=out)
+            except subprocess.CalledProcessError as e:
+                if e.returncode in (1, 2):  # abigail error, user error
+                    raise
+                return True  # actual abi change
+
+        return False  # no abi change
+
+def get_abi_tool(abi_tool):
+    if abi_tool == 'libabigail':
+        log.info('using libabigail for abi analysis')
+        return Libabigail()
+
+    raise ValueError("not a valid abi_tool: %s" % abi_tool)
+
diff --git a/abi/diff_abi b/abi/diff_abi
new file mode 100755
index 0000000..7ea4448
--- /dev/null
+++ b/abi/diff_abi
@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2019 The Android Open Source Project
+#
+# 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.
+#
+
+import argparse
+import os
+import sys
+
+from abitool import get_abi_tool
+
+def diff_abi(abitool, baseline, new, out_file):
+    tool = get_abi_tool(abitool)
+    return tool.diff_abi(baseline, new, out_file)
+
+def main():
+    """ Build the linux kernel, freshly cloning if needed"""
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--baseline', help='baseline dump to compare to',
+                        required=True)
+    parser.add_argument('--new', help='new dump to compare to baseline',
+                        required=True)
+    parser.add_argument('--abi-tool', default='libabigail',
+                        help='abi tool to be used to monitor abi')
+    parser.add_argument('--report', help='where to write the report to',
+                        required=True)
+
+    args = parser.parse_args()
+
+    abi_changed = diff_abi(args.abi_tool,
+                           args.baseline,
+                           args.new,
+                           args.report)
+    if abi_changed:
+        return 8
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/abi/dump_abi b/abi/dump_abi
new file mode 100755
index 0000000..3791504
--- /dev/null
+++ b/abi/dump_abi
@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2019 The Android Open Source Project
+#
+# 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.
+#
+
+import argparse
+import os
+import sys
+
+from abitool import get_abi_tool
+
+def dump_abi(abitool, linux_tree, out_file):
+    tool = get_abi_tool(abitool)
+    tool.dump_kernel_abi(linux_tree, out_file)
+
+def main():
+    """ Build the linux kernel, freshly cloning if needed"""
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--linux-tree',
+                        help='Path to kernel tree containing '
+                             'vmlinux and modules',
+                        required=True)
+    parser.add_argument('--abi-tool', default='libabigail',
+                        help='abi tool to be used to monitor abi')
+    parser.add_argument('--out-file', default=None,
+                        help='where to write the abi dump to')
+
+    args = parser.parse_args()
+
+    dump_abi(args.abi_tool,
+             args.linux_tree,
+             args.out_file or os.path.join(args.linux_tree, "abi.out"))
+
+if __name__ == "__main__":
+    sys.exit(main())