The new regexec_buf() function operates on buffers with an explicitly
specified length, rather than NUL-terminated strings.
We need to use this function whenever the buffer we want to pass to
regexec() may have been mmap()ed (and is hence not NUL-terminated).
Note: the original motivation for this patch was to fix a bug where
`git diff -G <regex>` would crash. This patch converts more callers,
though, some of which explicitly allocated and constructed
NUL-terminated strings (or worse: modified read-only buffers to insert
NULs).
Some of the buffers actually may be NUL-terminated. As regexec_buf()
uses REG_STARTEND where available, but has to fall back to allocating
and constructing NUL-terminated strings where REG_STARTEND is not
available, this makes the code less efficient in the latter case.
However, given the widespread support for REG_STARTEND, combined with
the improved ease of code maintenance, we strike the balance in favor
of REG_STARTEND.
Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
---
diff.c | 3 ++-
diffcore-pickaxe.c | 18 ++++++++----------
t/t4061-diff-pickaxe.sh | 2 +-
xdiff-interface.c | 13 ++++---------
4 files changed, 15 insertions(+), 21 deletions(-)
diff --git a/diff.c b/diff.c
index 534c12e..526775a 100644
--- a/diff.c
+++ b/diff.c
@@ -951,7 +951,8 @@ static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
{
if (word_regex && *begin < buffer->size) {
regmatch_t match[1];
- if (!regexec(word_regex, buffer->ptr + *begin, 1, match, 0)) {
+ if (!regexec_buf(word_regex, buffer->ptr + *begin,
+ buffer->size - *begin, 1, match, 0)) {
char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
'\n', match[0].rm_eo - match[0].rm_so);
*end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
diff --git a/diffcore-pickaxe.c b/diffcore-pickaxe.c
index 55067ca..9795ca1 100644
--- a/diffcore-pickaxe.c
+++ b/diffcore-pickaxe.c
@@ -23,7 +23,6 @@ static void diffgrep_consume(void *priv, char *line, unsigned long len)
{
struct diffgrep_cb *data = priv;
regmatch_t regmatch;
- int hold;
if (line[0] != '+' && line[0] != '-')
return;
@@ -33,11 +32,8 @@ static void diffgrep_consume(void *priv, char *line, unsigned long len)
* caller early.
*/
return;
- /* Yuck -- line ought to be "const char *"! */
- hold = line[len];
- line[len] = '\0';
- data->hit = !regexec(data->regexp, line + 1, 1, ®match, 0);
- line[len] = hold;
+ data->hit = !regexec_buf(data->regexp, line + 1, len - 1, 1,
+ ®match, 0);
}
static int diff_grep(mmfile_t *one, mmfile_t *two,
@@ -50,9 +46,11 @@ static int diff_grep(mmfile_t *one, mmfile_t *two,
xdemitconf_t xecfg;
if (!one)
- return !regexec(regexp, two->ptr, 1, ®match, 0);
+ return !regexec_buf(regexp, two->ptr, two->size,
+ 1, ®match, 0);
if (!two)
- return !regexec(regexp, one->ptr, 1, ®match, 0);
+ return !regexec_buf(regexp, one->ptr, one->size,
+ 1, ®match, 0);
/*
* We have both sides; need to run textual diff and see if
@@ -83,8 +81,8 @@ static unsigned int contains(mmfile_t *mf, regex_t *regexp, kwset_t kws)
regmatch_t regmatch;
int flags = 0;
- assert(data[sz] == '\0');
- while (*data && !regexec(regexp, data, 1, ®match, flags)) {
+ while (*data &&
+ !regexec_buf(regexp, data, sz, 1, ®match, flags)) {
flags |= REG_NOTBOL;
data += regmatch.rm_eo;
if (*data && regmatch.rm_so == regmatch.rm_eo)
diff --git a/t/t4061-diff-pickaxe.sh b/t/t4061-diff-pickaxe.sh
index 5929f2e..f0bf50b 100755
--- a/t/t4061-diff-pickaxe.sh
+++ b/t/t4061-diff-pickaxe.sh
@@ -14,7 +14,7 @@ test_expect_success setup '
test_tick &&
git commit -m "A 4k file"
'
-test_expect_failure '-G matches' '
+test_expect_success '-G matches' '
git diff --name-only -G "^0{4096}$" HEAD^ >out &&
test 4096-zeroes.txt = "$(cat out)"
'
diff --git a/xdiff-interface.c b/xdiff-interface.c
index f34ea76..50702a2 100644
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -214,11 +214,10 @@ struct ff_regs {
static long ff_regexp(const char *line, long len,
char *buffer, long buffer_size, void *priv)
{
- char *line_buffer;
struct ff_regs *regs = priv;
regmatch_t pmatch[2];
int i;
- int result = -1;
+ int result;
/* Exclude terminating newline (and cr) from matching */
if (len > 0 && line[len-1] == '\n') {
@@ -228,18 +227,16 @@ static long ff_regexp(const char *line, long len,
len--;
}
- line_buffer = xstrndup(line, len); /* make NUL terminated */
-
for (i = 0; i < regs->nr; i++) {
struct ff_reg *reg = regs->array + i;
- if (!regexec(®->re, line_buffer, 2, pmatch, 0)) {
+ if (!regexec_buf(®->re, line, len, 2, pmatch, 0)) {
if (reg->negate)
- goto fail;
+ return -1;
break;
}
}
if (regs->nr <= i)
- goto fail;
+ return -1;
i = pmatch[1].rm_so >= 0 ? 1 : 0;
line += pmatch[i].rm_so;
result = pmatch[i].rm_eo - pmatch[i].rm_so;
@@ -248,8 +245,6 @@ static long ff_regexp(const char *line, long len,
while (result > 0 && (isspace(line[result - 1])))
result--;
memcpy(buffer, line, result);
- fail:
- free(line_buffer);
return result;
}
--
2.10.0.windows.1.10.g803177d