criu/scripts/magic-gen.py

#!/bin/env python3
import sys


# This program parses criu magic.h file and produces
# magic.py with all *_MAGIC constants except RAW and V1.
def main(argv):
    if len(argv) != 3:
        print("Usage: magic-gen.py path/to/image.h path/to/magic.py")
        exit(1)

    magic_c_header = argv[1]
    magic_py = argv[2]

    # all_magic is used to parse constructions like:
    # #define PAGEMAP_MAGIC          0x56084025
    # #define SHMEM_PAGEMAP_MAGIC    PAGEMAP_MAGIC
    all_magic = {}
    # and magic is used to store only unique magic.
    magic = {}

    with open(magic_c_header, 'r') as f:
        for line in f:
            split = line.split()

            if len(split) < 3:
                continue

            if '#define' not in split[0]:
                continue

            key = split[1]
            value = split[2]

            if value in all_magic:
                value = all_magic[value]
            else:
                magic[key] = value

            all_magic[key] = value

    with open(magic_py, 'w+') as out:
        out.write('#Autogenerated. Do not edit!\n')
        out.write('by_name = {}\n')
        out.write('by_val = {}\n')
        for k, v in list(magic.items()):
            # We don't need RAW or V1 magic, because
            # they can't be used to identify images.
            if v == '0x0' or v == '1' or k == '0x0' or v == '1':
                continue
            if k.endswith("_MAGIC"):
                # Just cutting _MAGIC suffix
                k = k[:-6]
            v = int(v, 16)
            out.write("by_name['" + k + "'] = " + str(v) + "\n")
            out.write("by_val[" + str(v) + "] = '" + k + "'\n")


if __name__ == "__main__":
    main(sys.argv)