Asserts when encountering invalid files

[Winterhuman]

Version: 0.11-1
systemd: 256.9-1
kernel: 6.12.4-arch1-1

While writing a script to find all dl-opened libraries on a system, I ran into this assert when encountering .py files:

Traceback (most recent call last):
  File "/usr/bin/dlopen-notes", line 142, in <module>
    notes = [read_dlopen_notes(filename) for filename in args.filenames]
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/bin/dlopen-notes", line 24, in wrap
    return list(f(*args, **kwargs))
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/bin/dlopen-notes", line 29, in read_dlopen_notes
    elffile = ELFFile(open(filename, 'rb'))
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/site-packages/elftools/elf/elffile.py", line 84, in __init__
    self._identify_file()
  File "/usr/lib/python3.12/site-packages/elftools/elf/elffile.py", line 570, in _identify_file
    elf_assert(magic == b'\x7fELF', 'Magic number does not match')
  File "/usr/lib/python3.12/site-packages/elftools/common/utils.py", line 80, in elf_assert
    _assert_with_exception(cond, msg, ELFError)
  File "/usr/lib/python3.12/site-packages/elftools/common/utils.py", line 143, in _assert_with_exception
    raise exception_type(msg)
elftools.common.exceptions.ELFError: Magic number does not match

Ideally, invalid & non-existent files (& directories) wouldn't cause asserts like this.

[keszybz]

I think the idea is to just not invoke it on files that it doesn't understand. We could add a wrapper not to print the exception, but having it printed helps with debuging… This is not a "crash", just "graceful verbose error handling" ;)