cksum: add --raw option to output a binary digest

--raw output is the most composable format, and also is a
robust way to discard the file name without parsing (escaped) output.

Examples:

  $ cksum --raw -a crc "$afile" | basenc --base16
  4ACFC4F0

  $ cksum --raw -a crc "$afile" | basenc --base2msbf
  01001010110011111100010011110000

  $ cksum --raw -a sha256 "$bfile" | basenc --base32
  AAAAAAAADHLGRHAILLQWLAY6SNH7OY5OI2RKNQLSWPY3MCUM4JXQ====

* doc/coreutils.texi (cksum invocation): Describe the new feature.
* src/digest.c (output_file): Inspect the new RAW_DIGEST global,
and output the bytes directly if set.
* src/cksum.c (output_crc): Likewise.
* src/sum.c (output_bsd, output_sysv): Likewise.
* tests/misc/cksum-raw.sh: A new test.
* tests/local.mk: Reference the new test.
* NEWS: Mention the new feature.

2 files changed, 61 insertions, 0 deletions

diff --git a/tests/local.mk b/tests/local.mk
index 70a8f6e73..4c40fd115 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -294,6 +294,7 @@ all_tests =					\
   tests/misc/cksum-a.sh				\
   tests/misc/cksum-c.sh				\
   tests/misc/cksum-base64.pl			\
+  tests/misc/cksum-raw.sh			\
   tests/misc/comm.pl				\
   tests/misc/csplit.sh				\
   tests/misc/csplit-1000.sh			\
diff --git a/tests/misc/cksum-raw.sh b/tests/misc/cksum-raw.sh
new file mode 100755
index 000000000..a5f14be88
--- /dev/null
+++ b/tests/misc/cksum-raw.sh
@@ -0,0 +1,60 @@
+#!/bin/sh
+# Validate cksum --raw operation
+
+# 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/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ cksum date od
+
+cat > digest_types <<\EOF || framework_failure_
+bsd     u2
+sysv    u2
+crc     u4
+md5     x1
+sha1    x1
+sha224  x1
+sha256  x1
+sha384  x1
+sha512  x1
+blake2b x1
+sm3     x1
+EOF
+
+date > file.in || framework_failure_
+
+while read algo type; do
+  # Binary converted back to text
+  cksum --raw --algorithm $algo file.in > digest.bin || fail=1
+  d='digest.bin.txt'
+  od --endian=big -An -w1024 -t$type < digest.bin | tr -d ' ' \
+    > "$d" || framework_failure_
+  # Pad the bsd checksum with leading 0's, if needed.
+  case $algo in bsd) n=$(cat "$d"); printf '%05d\n' "$n" > "$d" ;; esac
+
+  # Standard text output
+  cksum --untagged --algorithm $algo < file.in | cut -d ' ' -f1 \
+    > digest.txt || fail=1
+
+  compare digest.txt "$d" || fail=1
+done < digest_types
+
+# Ensure --base64 and --raw not used together
+returns_ 1 cksum --base64 --raw </dev/null || fail=1
+
+# Ensure --raw not supported with multiple files
+returns_ 1 cksum --raw /dev/null /dev/null || fail=1
+
+Exit $fail