cksum: accept new option: --base64 (-b)

* src/digest.c [HASH_ALGO_CKSUM]: Include "base64.h"
[HASH_ALGO_CKSUM] (base64_digest): New global.
[HASH_ALGO_CKSUM] (enum BASE64_DIGEST_OPTION): New enum.
[HASH_ALGO_CKSUM] (long_options): Add "base64".
(valid_digits): Rename from hex_digits, now taking an input length argument.
Adjust callers.
(bsd_split_3): Rename arg from hex_digits to digest.
Add new *d_len parameter for length of extracted digest.
Move "i" declaration down to first use.
(split_3): Rename arg from hex_digits to digest.
Add new *d_len parameter for length of extracted digest.
Instead of relying on "known" length of digest to find the following
must-be-whitespace byte, search for the first whitespace byte.
[HASH_ALGO_CKSUM] (output_file): Handle base64_digest.
[HASH_ALGO_CKSUM] (main): Set base64_digest.
[HASH_ALGO_CKSUM] (b64_equal): New function.
(hex_equal): New function, factored out of digest_check.
(digest_check) Factored part into b64_equal and hex_equal.
Rename local hex_digest to digest.
* tests/misc/cksum-base64.pl: Add tests.
* tests/local.mk (all_tests): Add to the list.
* cfg.mk (_cksum): Define.
(exclude_file_name_regexp--sc_prohibit_test_backticks): Exempt new test.
(exclude_file_name_regexp--sc_long_lines): Likewise.
* doc/coreutils.texi (cksum invocation): Document it.
(md5sum invocation) [--check]: Mention digest encoding auto-detect.
* NEWS (New Features): Mention this.

2 files changed, 100 insertions, 0 deletions

diff --git a/tests/local.mk b/tests/local.mk
index f6e3746b6..70a8f6e73 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -293,6 +293,7 @@ all_tests =					\
   tests/misc/cksum.sh				\
   tests/misc/cksum-a.sh				\
   tests/misc/cksum-c.sh				\
+  tests/misc/cksum-base64.pl			\
   tests/misc/comm.pl				\
   tests/misc/csplit.sh				\
   tests/misc/csplit-1000.sh			\
diff --git a/tests/misc/cksum-base64.pl b/tests/misc/cksum-base64.pl
new file mode 100755
index 000000000..4fec7a5d7
--- /dev/null
+++ b/tests/misc/cksum-base64.pl
@@ -0,0 +1,99 @@
+#!/usr/bin/perl
+# Exercise cksum's --base64 option.
+
+# Copyright (C) 2023 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use strict;
+
+(my $program_name = $0) =~ s|.*/||;
+
+# Turn off localization of executable's output.
+@ENV{qw(LANGUAGE LANG LC_ALL)} = ('C') x 3;
+
+# Pairs of hash,degenerate_output, given file name of "f":
+my @pairs =
+  (
+   ['sysv', "0 0 f"],
+   ['bsd', "00000     0 f"],
+   ['crc', "4294967295 0 f"],
+   ['md5', "1B2M2Y8AsgTpgAmY7PhCfg=="],
+   ['sha1', "2jmj7l5rSw0yVb/vlWAYkK/YBwk="],
+   ['sha224', "0UoCjCo6K8lHYQK7KII0xBWisB+CjqYqxbPkLw=="],
+   ['sha256', "47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU="],
+   ['sha384', "OLBgp1GsljhM2TJ+sbHjaiH9txEUvgdDTAzHv2P24donTt6/529l+9Ua0vFImLlb"],
+   ['sha512', "z4PhNX7vuL3xVChQ1m2AB9Yg5AULVxXcg/SpIdNs6c5H0NE8XYXysP+DGNKHfuwvY7kxvUdBeoGlODJ6+SfaPg=="],
+   ['blake2b', "eGoC90IBWQPGxv2FJVLScpEvR0DhWEdhiobiF/cfVBnSXhAxr+5YUxOJZESTTrBLkDpoWxRIt1XVb3Aa/pvizg=="],
+   ['sm3', "GrIdg1XPoX+OYRlIMegajyK+yMco/vt0ftA161CCqis="],
+  );
+
+# Return the formatted output for a given hash name/value pair.
+# Use the hard-coded "f" as file name.
+sub fmt ($$) {
+  my ($h, $v) = @_;
+  $h !~ m{^(sysv|bsd|crc)$} and $v = uc($h). " (f) = $v";
+  # BLAKE2b is inconsistent:
+  $v =~ s{BLAKE2B}{BLAKE2b};
+  return "$v"
+}
+
+my @Tests =
+  (
+   # Ensure that each of the above works with -b:
+   (map {my ($h,$v)= @$_; my $o=fmt $h,$v;
+         [$h, "-ba $h", {IN=>{f=>''}}, {OUT=>"$o\n"}]} @pairs),
+
+   # For each that accepts --check, ensure that works with base64 digests:
+   (map {my ($h,$v)= @$_; my $o=fmt $h,$v;
+         ["chk-".$h, "--check --strict", {IN=>$o},
+          {AUX=>{f=>''}}, {OUT=>"f: OK\n"}]}
+      grep { $_->[0] !~ m{^(sysv|bsd|crc)$} } @pairs),
+
+   # For digests ending in "=", ensure --check fails if any "=" is removed.
+   (map {my ($h,$v)= @$_; my $o=fmt $h,$v;
+         ["chk-eq1-".$h, "--check", {IN=>$o}, {AUX=>{f=>''}},
+          {ERR_SUBST=>"s/.*: //"}, {OUT=>''}, {EXIT=>1},
+          {ERR=>"no properly formatted checksum lines found\n"}]}
+      ( map {my ($h,$v)=@$_; $v =~ s/=$//; [$h,$v] }
+        grep { $_->[1] =~ m{=$} } @pairs)),
+
+   # Same as above, but for those ending in "==":
+   (map {my ($h,$v)= @$_; my $o=fmt $h,$v;
+         ["chk-eq2-".$h, "--check", {IN=>$o}, {AUX=>{f=>''}},
+          {ERR_SUBST=>"s/.*: //"}, {OUT=>''}, {EXIT=>1},
+          {ERR=>"no properly formatted checksum lines found\n"}]}
+      ( map {my ($h,$v)=@$_; $v =~ s/==$//; [$h,$v] }
+        grep { $_->[1] =~ m{==$} } @pairs)),
+
+   # Trigger a read-buffer-overrun error in an early (not committed)
+   # version of the --base64-adding patch.
+   ['nul', '-a sha1 --check', {IN=>'\0\0\0'},
+    {ERR=>"no properly formatted checksum lines found\n"},
+    {ERR_SUBST=>"s/.*: //"}, {OUT=>''}, {EXIT=>1}],
+  );
+
+my $save_temps = $ENV{DEBUG};
+my $verbose = $ENV{VERBOSE};
+
+my $prog = 'cksum';
+my $fail = run_tests ($program_name, $prog, \@Tests, $save_temps, $verbose);
+
+# Ensure hash names from cksum --help match those in @pairs above.
+my $help_algs = join ' ', map { m{^  ([[:alpha:]]\S+)} }
+  grep { m{^  ([[:alpha:]]\S+)} } split ('\n', `cksum --help`);
+my $test_algs = join ' ', map {$_->[0]} @pairs;
+$help_algs eq $test_algs or die "$help_algs not equal to\n$test_algs";
+
+exit $fail;