[PATCH] grep: disable lookahead on error
regexec(3) can fail. E.g. on macOS it fails if it is used with an UTF-8 locale to match a valid regex against a buffer containing invalid UTF-8 characters.
git grep has two ways to search for matches in a file: Either it splits its contents into lines and matches them separately, or it matches the whole content and figures out line boundaries later. The latter is done by look_ahead() and it's quicker in the common case where most files don't contain a match.
Fall back to line-by-line matching if look_ahead() encounters an regexec(3) error by propagating errors out of patmatch() and bailing out of look_ahead() if there is one. This way we at least can find matches in lines that contain only valid characters. That matches the behavior of grep(1) on macOS.
pcre2match() dies if pcre2_jit_match() or pcre2_match() fail, but since we use the flag PCRE2_MATCH_INVALID_UTF it handles invalid UTF-8 characters gracefully. So implement the fall-back only for regexec(3) and leave the PCRE2 matching unchanged.
Reported-by: David Gstir <david@sigma-star.at>
Signed-off-by: René Scharfe <l.s.r@web.de>
---
grep.c | 30 ++++++++++++++++++++----------
t/t7810-grep.sh | 9 +++++++++
2 files changed, 29 insertions(+), 10 deletions(-)
diff --git a/grep.c b/grep.c
index 701e58de04..506f0423c8 100644
--- a/grep.c
+++ b/grep.c
@@ -906,15 +906,17 @@ static int patmatch(struct grep_pat *p,
const char *line, const char *eol,
regmatch_t *match, int eflags)
{
- int hit;
-
if (p->pcre2_pattern)
- hit = !pcre2match(p, line, eol, match, eflags);
- else
- hit = !regexec_buf(&p->regexp, line, eol - line, 1, match,
- eflags);
+ return !pcre2match(p, line, eol, match, eflags);
- return hit;
+ switch (regexec_buf(&p->regexp, line, eol - line, 1, match, eflags)) {
+ case 0:
+ return 1;
+ case REG_NOMATCH:
+ return 0;
+ default:
+ return -1;
+ }
}
static void strip_timestamp(const char *bol, const char **eol_p)
@@ -952,6 +954,8 @@ static int headerless_match_one_pattern(struct grep_pat *p,
again:
hit = patmatch(p, bol, eol, pmatch, eflags);
+ if (hit < 0)
+ hit = 0;
if (hit && p->word_regexp) {
if ((pmatch[0].rm_so < 0) ||
@@ -1461,6 +1465,8 @@ static int look_ahead(struct grep_opt *opt,
regmatch_t m;
hit = patmatch(p, bol, bol + *left_p, &m, 0);
+ if (hit < 0)
+ return -1;
if (!hit || m.rm_so < 0 || m.rm_eo < 0)
continue;
if (earliest < 0 || m.rm_so < earliest)
@@ -1655,9 +1661,13 @@ static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int colle
if (try_lookahead
&& !(last_hit
&& (show_function ||
- lno <= last_hit + opt->post_context))
- && look_ahead(opt, &left, &lno, &bol))
- break;
+ lno <= last_hit + opt->post_context))) {
+ hit = look_ahead(opt, &left, &lno, &bol);
+ if (hit < 0)
+ try_lookahead = 0;
+ else if (hit)
+ break;
+ }
eol = end_of_line(bol, &left);
if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index af2cf2f78a..64ac4f04ee 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -87,6 +87,7 @@ test_expect_success setup '
# Still a no-op.
function dummy() {}
EOF
+ printf "\200\nASCII\n" >invalid-utf8 &&
if test_have_prereq FUNNYNAMES
then
echo unusual >"\"unusual\" pathname" &&
@@ -534,6 +535,14 @@ do
test_cmp expected actual
'
+ test_expect_success "grep $L searches past invalid lines on UTF-8 locale" '
+ LC_ALL=en_US.UTF-8 git grep A. invalid-utf8 >actual &&
+ cat >expected <<-EOF &&
+ invalid-utf8:ASCII
+ EOF
+ test_cmp expected actual
+ '
+
test_expect_success FUNNYNAMES "grep $L should quote unusual pathnames" '
cat >expected <<-EOF &&
${HC}"\"unusual\" pathname":unusual
--
2.47.0
