From 194029ffaf74282a81f0c299c07f73caca3232ca Mon Sep 17 00:00:00 2001 From: Lasse Collin Date: Mon, 11 Jan 2021 22:01:51 +0200 Subject: [PATCH] Scripts: Fix exit status of xzdiff/xzcmp. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This is a minor fix since this affects only the situation when the files differ and the exit status is something else than 0. In such case there could be SIGPIPE from a decompression tool and that would result in exit status of 2 from xzdiff/xzcmp while the correct behavior would be to return 1 or whatever else diff or cmp may have returned. This commit omits the -q option from xz/gzip/bzip2/lzop arguments. I'm not sure why the -q was used in the first place, perhaps it hides warnings in some situation that I cannot see at the moment. Hopefully the removal won't introduce a new bug. With gzip the -q option was harmful because it made gzip return 2 instead of >= 128 with SIGPIPE. Ignoring exit status 2 (warning from gzip) isn't practical because bzip2 uses exit status 2 to indicate corrupt input file. It's better if SIGPIPE results in exit status >= 128. With bzip2 the removal of -q seems to be good because with -q it prints nothing if input is corrupt. The other tools aren't silent in this situation even with -q. On the other hand, if zstd support is added, it will need -q since otherwise it's noisy in normal situations. Thanks to Étienne Mollier and Sebastian Andrzej Siewior. --- src/scripts/xzdiff.in | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) diff --git a/src/scripts/xzdiff.in b/src/scripts/xzdiff.in index eb7825c..98ac0e5 100644 --- a/src/scripts/xzdiff.in +++ b/src/scripts/xzdiff.in @@ -116,23 +116,18 @@ elif test $# -eq 2; then if test "$1$2" = --; then xz_status=$( exec 4>&1 - ($xz1 -cdfq - 4>&-; echo $? >&4) 3>&- | + ($xz1 -cdf - 4>&-; echo $? >&4) 3>&- | eval "$cmp" - - >&3 ) elif # Reject Solaris 8's buggy /bin/bash 2.03. echo X | (echo X | eval "$cmp" /dev/fd/5 - >/dev/null 2>&1) 5<&0; then + # NOTE: xz_status will contain two numbers. xz_status=$( exec 4>&1 - ($xz1 -cdfq -- "$1" 4>&-; echo $? >&4) 3>&- | - ( ($xz2 -cdfq -- "$2" 4>&-; echo $? >&4) 3>&- 5<&- &-; echo $? >&4) 3>&- | + ( ($xz2 -cdf -- "$2" 4>&-; echo $? >&4) 3>&- 5<&- &3) 5<&0 ) - cmp_status=$? - case $xz_status in - *[1-9]*) xz_status=1;; - *) xz_status=0;; - esac - (exit $cmp_status) else F=`expr "/$2" : '.*/\(.*\)[-.][ablmotxz2]*$'` || F=$prog tmp= @@ -161,10 +156,10 @@ elif test $# -eq 2; then mkdir -- "${TMPDIR-/tmp}/$prog.$$" || exit 2 tmp="${TMPDIR-/tmp}/$prog.$$" fi - $xz2 -cdfq -- "$2" > "$tmp/$F" || exit 2 + $xz2 -cdf -- "$2" > "$tmp/$F" || exit 2 xz_status=$( exec 4>&1 - ($xz1 -cdfq -- "$1" 4>&-; echo $? >&4) 3>&- | + ($xz1 -cdf -- "$1" 4>&-; echo $? >&4) 3>&- | eval "$cmp" - '"$tmp/$F"' >&3 ) cmp_status=$? @@ -175,7 +170,7 @@ elif test $# -eq 2; then *) xz_status=$( exec 4>&1 - ($xz1 -cdfq -- "$1" 4>&-; echo $? >&4) 3>&- | + ($xz1 -cdf -- "$1" 4>&-; echo $? >&4) 3>&- | eval "$cmp" - '"$2"' >&3 );; esac;; @@ -184,7 +179,7 @@ elif test $# -eq 2; then *[-.][zZ] | *_z | *[-.][gx]z | *[-.]bz2 | *[-.]lzma | *.t[abglx]z | *.tbz2 | *[-.]lzo | *.tzo | -) xz_status=$( exec 4>&1 - ($xz2 -cdfq -- "$2" 4>&-; echo $? >&4) 3>&- | + ($xz2 -cdf -- "$2" 4>&-; echo $? >&4) 3>&- | eval "$cmp" '"$1"' - >&3 );; *) @@ -197,5 +192,17 @@ else fi cmp_status=$? -test "$xz_status" -eq 0 || exit 2 +for num in $xz_status ; do + # 0 from decompressor means successful decompression. SIGPIPE from + # decompressor is possible when diff or cmp exits before the whole file + # has been decompressed. In that case we want to retain the exit status + # from diff or cmp. Note that using "trap '' PIPE" is not possible + # because gzip changes its behavior (including exit status) if SIGPIPE + # is ignored. + test "$num" -eq 0 && continue + test "$num" -ge 128 \ + && test "$(kill -l "$num" 2> /dev/null)" = "PIPE" \ + && continue + exit 2 +done exit $cmp_status