db-check-package-libraries: Make it more robust.

First, to ease debugging, put some information in tmpdir filenames.

Then, to avoid issues with reading files that are mode unreadable, or
stat()ing them in unexecutable directories, add two `find` commands
that reset bad permissions to 755/644.

Then, skip over symlinks.  Beside absolute links being broken in our
implementation, it also means that links to files in different
packages are broken.  This leads to an exception being thrown, as the
file can't be open()ed.

Finally, skip over non-regular-file files.  One package I tried
contained a named FIFO, which caused it to hang on open().

1 files changed, 13 insertions, 3 deletions

diff --git a/db-check-package-libraries b/db-check-package-libraries
index 612fc4f..e24b58e 100755
--- a/db-check-package-libraries
+++ b/db-check-package-libraries
@@ -89,9 +89,17 @@ def add_package(con, package):
     # Extract to a temporary directory.  This could be done more
     # efficiently, since there is no need to store more than one file
     # at once.
-    with tempfile.TemporaryDirectory() as temp:
-        tar = subprocess.Popen(("bsdtar", "xf", package, "-C", temp))
-        tar.communicate()
+    print("adding package:", package)
+    with tempfile.TemporaryDirectory(None, "db-check-package-libraries."+os.path.basename(package)+".") as temp:
+        subprocess.Popen(("bsdtar", "xf", package, "-C", temp)).communicate()
+        subprocess.Popen(('find', temp,
+                          '-type', 'd',
+                          '(', '-not', '-readable', '-o', '-not', '-executable', ')',
+                          '-exec', 'chmod', '755', '--', '{}', ';')).communicate()
+        subprocess.Popen(('find', temp,
+                          '-type', 'f',
+                          '-not', '-readable',
+                          '-exec', 'chmod', '644', '--', '{}', ';')).communicate()
         with open(os.path.join(temp, ".PKGINFO")) as pkginfo:
             for line in pkginfo:
                 if line.startswith("pkgname ="):
@@ -106,6 +114,8 @@ def add_package(con, package):
             assert dirnames is not None  # unused, avoid pylint warning
             for file_name in filenames:
                 path = os.path.join(dirname, file_name)
+                if os.path.islink(path) or not os.path.isfile(path):
+                    continue
                 with open(path, "rb") as file_object:
                     if file_object.read(4) != b"\177ELF":
                         continue