def process_library()

in test-snapshot-binaries/linux_load_commands.py [0:0]

• 39 lines of code
• 11 McCabe index (conditional complexity)

def process_library(args, lib):
    assert(len(lib) > 0)

    numberOfLines = None
    numberOfLinesSeen = 0

    print("Visiting lib: {}".format(lib))
    lines = list(reversed(subprocess.check_output([args.read_elf, "--program-headers", lib], universal_newlines=True).split("\n")[:-1]))
    p = ParseState()

    # Until we finish parsing or run out of lines to parse...
    while len(lines) > 0:
        l = lines.pop()
        print("DUMP: '{}'".format(l))
        assert(p is not None)
        curState = p

        m = curState.matches(l)
        if m is None:
            continue

        p = curState.next
        if curState.value == ParseState.firstLine:
            numberOfLines = int(m.group(1))
            continue

        if curState.value == ParseState.programHeadersLine:
            continue

        if curState.value == ParseState.dataHeader:
            continue

        if curState.value == ParseState.data:
            val = m.group(1)
            if val == "LOAD":
                flags = m.group(2)
                print("Found LOAD command! Flags: '{}'. Full match: '{}'".format(flags, l))
                if "W" in flags and "E" in flags:
                    raise RuntimeError("Found a load command that loads something executable and writeable")

            # If we haven't seen enough lines, continue.
            assert(numberOfLines is not None)
            if numberOfLinesSeen != numberOfLines - 1:
                numberOfLinesSeen += 1
                continue

            # If we have seen enough lines, be sure to not only break out
            # of the switch, but additionally break out of the whole
            # parsing loop. We could go through the rest of the output from
            # llvm-readelf, but there isn't any point.
            p = None
            break

    # If we ran out of lines to parse without finishing parsing, we failed.
    assert(p is None)
    assert(numberOfLines is not None)
    assert(numberOfLinesSeen == numberOfLines - 1)