grep: fix grep -x to not set REG_NOSUB

When -F isn't specified (and !ENABLE_EXTRA_COMPAT), grep -x uses
regexec's regmatch_t output to determine if the match was the entire
line. However it also set the REG_NOSUB flag which makes it ignore the
regmatch_t argument.

Add an exception to the setting of REG_NOSUB for OPT_x and add some test
cases to test the behaviour of -x.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Natanael Copa <ncopa@alpinelinux.org>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/testsuite/grep.tests b/testsuite/grep.tests
index 5696fa7e1..64d99a905 100755
--- a/testsuite/grep.tests
+++ b/testsuite/grep.tests
@@ -82,6 +82,20 @@ testing "grep -F handles -i" "grep -F -i foo input ; echo \$?" \
 testing "grep can read regexps from stdin" "grep -f - input ; echo \$?" \
 	"two\nthree\n0\n" "tw\ntwo\nthree\n" "tw.\nthr\n"
 
+# -x (whole line match)
+testing "grep -x (full match)" "grep -x foo input ; echo \$?" \
+	"foo\n0\n" "foo\n" ""
+testing "grep -x (partial match 1)" "grep -x foo input ; echo \$?" \
+	"1\n" "foo bar\n" ""
+testing "grep -x (partial match 2)" "grep -x foo input ; echo \$?" \
+	"1\n" "bar foo\n" ""
+testing "grep -x -F (full match)" "grep -x -F foo input ; echo \$?" \
+	"foo\n0\n" "foo\n" ""
+testing "grep -x -F (partial match 1)" "grep -x -F foo input ; echo \$?" \
+	"1\n" "foo bar\n" ""
+testing "grep -x -F (partial match 2)" "grep -x -F foo input ; echo \$?" \
+	"1\n" "bar foo\n" ""
+
 optional FEATURE_GREP_EGREP_ALIAS
 testing "grep -E supports extended regexps" "grep -E fo+" "foo\n" "" \
 	"b\ar\nfoo\nbaz"