tests: rewrite file access checker in Python

As part of a goal to eliminate Perl from libvirt build tools,
rewrite the check-file-access.pl tool in Python.

This was a straight conversion, manually going line-by-line to
change the syntax from Perl to Python. Thus the overall structure
of the file and approach is the same.

Reviewed-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

scripts/check-file-access.py

@@ -0,0 +1,125 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2016-2019 Red Hat, Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library.  If not, see
+# <http://www.gnu.org/licenses/>.
+#
+# This script is supposed to check test_file_access.txt file and
+# warn about file accesses outside our working tree.
+#
+#
+
+import re
+import sys
+
+if len(sys.argv) != 3:
+    print("syntax: %s ACCESS-FILE ACCESS-WHITELIST")
+    sys.exit(1)
+
+access_file = sys.argv[1]
+whitelist_file = sys.argv[2]
+
+known_actions = ["open", "fopen", "access", "stat", "lstat", "connect"]
+
+files = []
+whitelist = []
+
+with open(access_file, "r") as fh:
+    for line in fh:
+        line = line.rstrip("\n")
+
+        m = re.search(r'''^(\S*):\s*(\S*):\s*(\S*)(\s*:\s*(.*))?$''', line)
+        if m is not None:
+            rec = {
+                "path": m.group(1),
+                "action": m.group(2),
+                "progname": m.group(3),
+                "testname": m.group(5),
+            }
+            files.append(rec)
+        else:
+            raise Exception("Malformed line %s" % line)
+
+with open(whitelist_file, "r") as fh:
+    for line in fh:
+        line = line.rstrip("\n")
+
+        if re.search(r'''^\s*#.*$''', line):
+            continue  # comment
+        if line == "":
+            continue
+
+        m = re.search(r'''^(\S*):\s*(\S*)(:\s*(\S*)(\s*:\s*(.*))?)?$''', line)
+        if m is not None and m.group(2) in known_actions:
+            # $path: $action: $progname: $testname
+            rec = {
+                "path": m.group(1),
+                "action": m.group(3),
+                "progname": m.group(4),
+                "testname": m.group(6),
+            }
+            whitelist.append(rec)
+        else:
+            m = re.search(r'''^(\S*)(:\s*(\S*)(\s*:\s*(.*))?)?$''', line)
+            if m is not None:
+                # $path: $progname: $testname
+                rec = {
+                    "path": m.group(1),
+                    "action": None,
+                    "progname": m.group(3),
+                    "testname": m.group(5),
+                }
+                whitelist.append(rec)
+            else:
+                raise Exception("Malformed line %s" % line)
+
+
+# Now we should check if %traces is included in $whitelist. For
+# now checking just keys is sufficient
+err = False
+for file in files:
+    match = False
+
+    for rule in whitelist:
+        if not re.match("^" + rule["path"] + "$", file["path"]):
+            continue
+
+        if (rule["action"] is not None and
+                not re.match("^" + rule["action"] + "$", file["action"])):
+            continue
+
+        if (rule["progname"] is not None and
+                not re.match("^" + rule["progname"] + "$", file["progname"])):
+            continue
+
+        if (rule["testname"] is not None and
+                file["testname"] is not None and
+                not re.match("^" + rule["testname"] + "$", file["testname"])):
+            continue
+
+        match = True
+
+    if not match:
+        err = True
+        print("%s: %s: %s" %
+              (file["path"], file["action"], file["progname"]),
+              end="")
+        if file["testname"] is not None:
+            print(": %s" % file["testname"], end="")
+        print("")
+
+if err:
+    sys.exit(1)
+sys.exit(0)