On 2021-01-08 Lasse Collin wrote:
> It's tempting to ignore exit statuses >= 128 at the end of the script
> where it current checks for "$xz_status" -eq 0 but that doesn't work
> because in the middle of the script there is also this:
>
> case $xz_status in
> *[1-9]*) xz_status=1;;
> *) xz_status=0;;
> esac
>
> There xz_status contains two numbers and the "case" finds out if they
> are both zero. Perhaps this "case" should be replaced with something
> more sophisticated that checks both numbers separately and ignores
> values >= 128.
I found it easy to change the above "case" and ignore >= 128 at the
bottom of the script. But that still isn't enough.
gzip -q turns SIGPIPE into exit status of 2. Ignoring 2 would work for
gzip but that is incompatible with bzip2 which uses exit status 2 to
indicate corrupt input. Trying to handle exit statuses separately for
each compressor is complicated because two different tools may be in
use at the same time. Getting rid of gzip -q sounds more reasonable.
The script uses -cdfq to decompress and I'm not sure why the -q is
there. There is an exception when only one argument is given, then -cd
is used. The -f option is needed with xz (and it's fine with gzip too)
to handle uncompressed files: xz -cdf or gzip -cdf with unknown file
format behaves like cat and just copies the input to the output. The
use of -f (and the non-use in the single-file case) looks fine, but I
don't know what to think about -q. Perhaps it hides warnings in some
rare cases where they aren't wanted.
The following patch replace -cdfq with -cdf and ignores decompressor
exit statuses >= 128. Could someone test if it fixes the original bug
without introducing any obvious new bugs with some of the supported
compression tools?
diff --git a/src/scripts/xzdiff.in b/src/scripts/xzdiff.in
index eb7825c..b285572 100644
--- a/src/scripts/xzdiff.in
+++ b/src/scripts/xzdiff.in
@@ -116,23 +116,17 @@ 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 "$cmp" /dev/fd/5 - >/dev/null 2>&1)
5<&0; then
xz_status=$(
exec 4>&1
- ($xz1 -cdfq -- "$1" 4>&-; echo $? >&4) 3>&- |
- ( ($xz2 -cdfq -- "$2" 4>&-; echo $? >&4) 3>&- 5<&- </dev/null |
+ ($xz1 -cdf -- "$1" 4>&-; echo $? >&4) 3>&- |
+ ( ($xz2 -cdf -- "$2" 4>&-; echo $? >&4) 3>&- 5<&- </dev/null |
eval "$cmp" /dev/fd/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 +155,10 @@ 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 +169,7 @@ 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 +178,7 @@ 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" '"$1"' - >&3
);;
*)
@@ -197,5 +191,9 @@ else
fi
cmp_status=$?
-test "$xz_status" -eq 0 || exit 2
+for num in $xz_status ; do
+ test "$num" -eq 0 && continue
+ test "$num" -ge 128 && continue
+ exit 2
+done
exit $cmp_status
--
Lasse Collin | IRC: Larhzu @ IRCnet & Freenode
