Hello,
while implementing whitelist mechanism in my shell scripting, I've
noticed an inconsistency between busybox's grep and GNU grep. They
handle -xf EMPTY_FILE flags differently when EMPTY_FILE is well...
empty.
GNU grep in that case handles it as if /.*/ pattern was provided, while
busybox uses //.
Attached patch fixes this issue. I've both added a test case into grep's
testsuite and I've also used following shell script to verify that the
behavior does match now:
#!/bin/sh
set -eu
# Sanity checks if this is run outside of my setup
[ ! -x ./busybox ] && ( echo >&2 './busybox missing'; exit 1 )
if ! grep --version | head -n1 | grep -Eq '^grep \(GNU grep\) '; then
echo >&2 'grep is not GNU grep'
exit 1
fi
[ -f empty ] && rm empty
[ -f blank ] && rm blank
touch empty
echo >blank
# Yeah yeah GNU grep is not coreutils, but core and busy both have 4 letters so
# it all nicely aligns.
tmpdir=/tmp/grep_test
bpref="$tmpdir/busy."
cpref="$tmpdir/core."
[ -d "$tmpdir" ] && rm -r "$tmpdir"
mkdir -p "$tmpdir"
busy_grep() {
./busybox grep "$@"
}
core_grep() {
grep "$@"
}
data() {
echo a
echo b
echo c
}
cmp() (
printf 'Test: %s ... ' "$*"
data | busy_grep "$@" >"$bpref$$" || :
data | core_grep "$@" >"$cpref$$" || :
if diff -u "$bpref$$" "$cpref$$" >/dev/null; then
echo 'OK'
else
echo 'FAIL'
diff -u "$bpref$$" "$cpref$$" || :
fi
)
cmp -Evxf ./empty
cmp -Evxf ./blank
cmp -Evf ./empty
cmp -Evf ./blank
cmp -Exf ./empty
cmp -Exf ./blank
cmp -vxf ./empty
cmp -vxf ./blank
cmp -Ef ./empty
cmp -Ef ./blank
cmp -vf ./empty
cmp -vf ./blank
cmp -xf ./empty
cmp -xf ./blank
cmp -f ./empty
cmp -f ./blank
With output being:
+ $ ./test.sh
Test: -Evxf ./empty ... OK
Test: -Evxf ./blank ... OK
Test: -Evf ./empty ... OK
Test: -Evf ./blank ... OK
Test: -Exf ./empty ... OK
Test: -Exf ./blank ... OK
Test: -vxf ./empty ... OK
Test: -vxf ./blank ... OK
Test: -Ef ./empty ... OK
Test: -Ef ./blank ... OK
Test: -vf ./empty ... OK
Test: -vf ./blank ... OK
Test: -xf ./empty ... OK
Test: -xf ./blank ... OK
Test: -f ./empty ... OK
Test: -f ./blank ... OK
_______________________________________________
busybox mailing list
[email protected]
http://lists.busybox.net/mailman/listinfo/busybox
