Python/apps/py-cutils: shasum.py comparison

comparison shasum.py @ 51:58d5a0b6e5b3

Implement the OpenBSD variant (with --base64) to encode digests in base64, not hexadecimal

author	Franz Glasner <f.glasner@feldmann-mg.com>
date	Wed, 26 Jan 2022 14:15:43 +0100
parents	5bec7a5d894a
children	5935055edea6

comparison

equal deleted inserted replaced

-:cc3d6fe7eda7
+:58d5a0b6e5b3
 __revision__ = "|VCSRevision|"
 __date__ = "|VCSJustDate|"
 import argparse
+import base64
+import binascii
 import hashlib
 import io
 try:
 import mmap
 except ImportError:
 fromfile_prefix_chars='@')
 aparser.add_argument(
 "--algorithm", "-a", action="store", type=argv2algo,
 help="1 (default), 224, 256, 384, 512, 3-224, 3-256, 3-384, 3-512, blake2b, blake2s, md5")
 aparser.add_argument(
+"--base64", action="store_true",
+help="output checksums in base64 notation, not hexadecimal (OpenBSD).")
+aparser.add_argument(
 "--binary", "-b", action="store_false", dest="text_mode", default=False,
 help="read in binary mode (default)")
 aparser.add_argument(
 "--bsd", "-B", action="store_true", dest="bsd", default=False,
 help="Write BSD style output. This is also the default output format of :command:`openssl dgst`.")
 return shasum(opts)
 def gen_opts(files=[], algorithm="SHA1", bsd=False, text_mode=False,
-checklist=False, check=False, dest=None):
+checklist=False, check=False, dest=None, base64=False):
 if text_mode:
 raise ValueError("text mode not supported")
 if checklist and check:
 raise ValueError("only one of `checklist' or `check' is allowed")
 opts = argparse.Namespace(files=files,
 algorithm),
 bsd=bsd,
 checklist=checklist,
 check=check,
 text_mode=False,
-dest=dest)
+dest=dest,
+base64=base64)
 return opts
 def shasum(opts):
 if opts.check:
 source = sys.stdin.buffer
 out(sys.stdout,
 compute_digest_stream(opts.algorithm[0], source),
 None,
 opts.algorithm[1],
-True)
+True,
+opts.base64)
 else:
 for fn in opts.files:
 out(opts.dest or sys.stdout,
 compute_digest_file(opts.algorithm[0], fn),
 fn,
 opts.algorithm[1],
-True)
+True,
+opts.base64)
 return 0
+def compare_digests_equal(given_digest, expected_digest, algo):
+"""Compare a newly computed binary digest `given_digest` with a digest
+string (hex or base64) in `expected_digest`.
+:param bytes given_digest:
+:param str expected_digest: hexlified or base64 encoded digest
+:param algo: The algorithm (factory)
+:return: `True` if the digests are equal, `False` if not
+:rtype: bool
+"""
+if len(expected_digest) == algo().digest_size * 2:
+# hex
+try:
+exd = binascii.unhexlify(expected_digest)
+except TypeError:
+return False
+else:
+# base64
+try:
+exd = base64.b64decode(expected_digest)
+except TypeError:
+return False
+return given_digest == exd
 def verify_digests_with_checklist(opts):
 dest = opts.dest or sys.stdout
 exit_code = 0
 exit_code = 1
 print("-: MISSING", file=dest)
 else:
 tag, algo, cl_filename, cl_digest = pl
 computed_digest = compute_digest_stream(algo, source)
-if cl_digest.lower() == computed_digest.lower():
+if compare_digests_equal(computed_digest, cl_digest, algo):
 res = "OK"
 else:
 res = "FAILED"
 exit_code = 1
 print("{}: {}: {}".format(tag, "-", res), file=dest)
 print("{}: MISSING".format(fn), file=dest)
 exit_code = 1
 else:
 tag, algo, cl_filename, cl_digest = pl
 computed_digest = compute_digest_file(algo, fn)
-if cl_digest.lower() == computed_digest.lower():
+if compare_digests_equal(computed_digest, cl_digest, algo):
 res = "OK"
 else:
 exit_code = 1
 res = "FAILED"
 print("{}: {}: {}".format(tag, fn, res), file=dest)
 raise ValueError(
 "improperly formatted digest line: {}".format(line))
 tag, algo, fn, digest = parts
 try:
 d = compute_digest_file(algo, fn)
-if d.lower() == digest.lower():
+if compare_digests_equal(d, digest, algo):
 return ("ok", fn, tag)
 else:
 return ("failed", fn, tag)
 except EnvironmentError:
 return ("missing", fn, tag)
 return hashlib.md5
 else:
 raise ValueError("unknown algorithm: {}".format(s))
-def out_bsd(dest, digest, filename, digestname, binary):
+def out_bsd(dest, digest, filename, digestname, binary, use_base64):
 """BSD format output, also :command:`openssl dgst` and
 :command:`b2sum --tag" format output
 """
+if use_base64:
+digest = base64.b64encode(digest).decode("ascii")
+else:
+digest = binascii.hexlify(digest).decode("ascii")
 if filename is None:
 print(digest, file=dest)
 else:
 print("{} ({}) = {}".format(digestname,
 normalize_filename(filename),
 digest),
 file=dest)
-def out_std(dest, digest, filename, digestname, binary):
+def out_std(dest, digest, filename, digestname, binary, use_base64):
 """Coreutils format (:command:`shasum` et al.)
 """
+if use_base64:
+digest = base64.b64encode(digest).decode("ascii")
+else:
+digest = binascii.hexlify(digest).decode("ascii")
 print("{} {}{}".format(
 digest,
 '*' if binary else ' ',
 '-' if filename is None else normalize_filename(filename)),
 file=dest)
 mapoffset += mapsize
 if rest < mapsize:
 mapsize = rest
 finally:
 os.close(fd)
-return h.hexdigest()
+return h.digest()
 def compute_digest_stream(hashobj, instream):
 """
 buf = instream.read(CHUNK_SIZE)
 if buf is not None:
 if len(buf) == 0:
 break
 h.update(buf)
-return h.hexdigest()
+return h.digest()
 def normalize_filename(filename, strip_leading_dot_slash=False):
 filename = filename.replace("\\", "/")
 if strip_leading_dot_slash:

Mercurial > hgrepos > Python > apps > py-cutils

comparison shasum.py @ 51:58d5a0b6e5b3