git/diffcore-pickaxe.c
Junio C Hamano 6a67695268 Merge branch 'js/regexec-buf'
Some codepaths in "git diff" used regexec(3) on a buffer that was
mmap(2)ed, which may not have a terminating NUL, leading to a read
beyond the end of the mapped region.  This was fixed by introducing
a regexec_buf() helper that takes a <ptr,len> pair with REG_STARTEND
extension.

* js/regexec-buf:
  regex: use regexec_buf()
  regex: add regexec_buf() that can work on a non NUL-terminated string
  regex: -G<pattern> feeds a non NUL-terminated string to regexec() and fails
2016-09-26 16:09:19 -07:00

252 lines
6.1 KiB
C

/*
* Copyright (C) 2005 Junio C Hamano
* Copyright (C) 2010 Google Inc.
*/
#include "cache.h"
#include "diff.h"
#include "diffcore.h"
#include "xdiff-interface.h"
#include "kwset.h"
#include "commit.h"
#include "quote.h"
typedef int (*pickaxe_fn)(mmfile_t *one, mmfile_t *two,
struct diff_options *o,
regex_t *regexp, kwset_t kws);
struct diffgrep_cb {
regex_t *regexp;
int hit;
};
static void diffgrep_consume(void *priv, char *line, unsigned long len)
{
struct diffgrep_cb *data = priv;
regmatch_t regmatch;
if (line[0] != '+' && line[0] != '-')
return;
if (data->hit)
/*
* NEEDSWORK: we should have a way to terminate the
* caller early.
*/
return;
data->hit = !regexec_buf(data->regexp, line + 1, len - 1, 1,
&regmatch, 0);
}
static int diff_grep(mmfile_t *one, mmfile_t *two,
struct diff_options *o,
regex_t *regexp, kwset_t kws)
{
regmatch_t regmatch;
struct diffgrep_cb ecbdata;
xpparam_t xpp;
xdemitconf_t xecfg;
if (!one)
return !regexec_buf(regexp, two->ptr, two->size,
1, &regmatch, 0);
if (!two)
return !regexec_buf(regexp, one->ptr, one->size,
1, &regmatch, 0);
/*
* We have both sides; need to run textual diff and see if
* the pattern appears on added/deleted lines.
*/
memset(&xpp, 0, sizeof(xpp));
memset(&xecfg, 0, sizeof(xecfg));
ecbdata.regexp = regexp;
ecbdata.hit = 0;
xecfg.ctxlen = o->context;
xecfg.interhunkctxlen = o->interhunkcontext;
if (xdi_diff_outf(one, two, diffgrep_consume, &ecbdata, &xpp, &xecfg))
return 0;
return ecbdata.hit;
}
static unsigned int contains(mmfile_t *mf, regex_t *regexp, kwset_t kws)
{
unsigned int cnt;
unsigned long sz;
const char *data;
sz = mf->size;
data = mf->ptr;
cnt = 0;
if (regexp) {
regmatch_t regmatch;
int flags = 0;
while (*data &&
!regexec_buf(regexp, data, sz, 1, &regmatch, flags)) {
flags |= REG_NOTBOL;
data += regmatch.rm_eo;
if (*data && regmatch.rm_so == regmatch.rm_eo)
data++;
cnt++;
}
} else { /* Classic exact string match */
while (sz) {
struct kwsmatch kwsm;
size_t offset = kwsexec(kws, data, sz, &kwsm);
if (offset == -1)
break;
sz -= offset + kwsm.size[0];
data += offset + kwsm.size[0];
cnt++;
}
}
return cnt;
}
static int has_changes(mmfile_t *one, mmfile_t *two,
struct diff_options *o,
regex_t *regexp, kwset_t kws)
{
unsigned int one_contains = one ? contains(one, regexp, kws) : 0;
unsigned int two_contains = two ? contains(two, regexp, kws) : 0;
return one_contains != two_contains;
}
static int pickaxe_match(struct diff_filepair *p, struct diff_options *o,
regex_t *regexp, kwset_t kws, pickaxe_fn fn)
{
struct userdiff_driver *textconv_one = NULL;
struct userdiff_driver *textconv_two = NULL;
mmfile_t mf1, mf2;
int ret;
if (!o->pickaxe[0])
return 0;
/* ignore unmerged */
if (!DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two))
return 0;
if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
textconv_one = get_textconv(p->one);
textconv_two = get_textconv(p->two);
}
/*
* If we have an unmodified pair, we know that the count will be the
* same and don't even have to load the blobs. Unless textconv is in
* play, _and_ we are using two different textconv filters (e.g.,
* because a pair is an exact rename with different textconv attributes
* for each side, which might generate different content).
*/
if (textconv_one == textconv_two && diff_unmodified_pair(p))
return 0;
mf1.size = fill_textconv(textconv_one, p->one, &mf1.ptr);
mf2.size = fill_textconv(textconv_two, p->two, &mf2.ptr);
ret = fn(DIFF_FILE_VALID(p->one) ? &mf1 : NULL,
DIFF_FILE_VALID(p->two) ? &mf2 : NULL,
o, regexp, kws);
if (textconv_one)
free(mf1.ptr);
if (textconv_two)
free(mf2.ptr);
diff_free_filespec_data(p->one);
diff_free_filespec_data(p->two);
return ret;
}
static void pickaxe(struct diff_queue_struct *q, struct diff_options *o,
regex_t *regexp, kwset_t kws, pickaxe_fn fn)
{
int i;
struct diff_queue_struct outq;
DIFF_QUEUE_CLEAR(&outq);
if (o->pickaxe_opts & DIFF_PICKAXE_ALL) {
/* Showing the whole changeset if needle exists */
for (i = 0; i < q->nr; i++) {
struct diff_filepair *p = q->queue[i];
if (pickaxe_match(p, o, regexp, kws, fn))
return; /* do not munge the queue */
}
/*
* Otherwise we will clear the whole queue by copying
* the empty outq at the end of this function, but
* first clear the current entries in the queue.
*/
for (i = 0; i < q->nr; i++)
diff_free_filepair(q->queue[i]);
} else {
/* Showing only the filepairs that has the needle */
for (i = 0; i < q->nr; i++) {
struct diff_filepair *p = q->queue[i];
if (pickaxe_match(p, o, regexp, kws, fn))
diff_q(&outq, p);
else
diff_free_filepair(p);
}
}
free(q->queue);
*q = outq;
}
static void regcomp_or_die(regex_t *regex, const char *needle, int cflags)
{
int err = regcomp(regex, needle, cflags);
if (err) {
/* The POSIX.2 people are surely sick */
char errbuf[1024];
regerror(err, regex, errbuf, 1024);
regfree(regex);
die("invalid regex: %s", errbuf);
}
}
void diffcore_pickaxe(struct diff_options *o)
{
const char *needle = o->pickaxe;
int opts = o->pickaxe_opts;
regex_t regex, *regexp = NULL;
kwset_t kws = NULL;
if (opts & (DIFF_PICKAXE_REGEX | DIFF_PICKAXE_KIND_G)) {
int cflags = REG_EXTENDED | REG_NEWLINE;
if (DIFF_OPT_TST(o, PICKAXE_IGNORE_CASE))
cflags |= REG_ICASE;
regcomp_or_die(&regex, needle, cflags);
regexp = &regex;
} else if (DIFF_OPT_TST(o, PICKAXE_IGNORE_CASE) &&
has_non_ascii(needle)) {
struct strbuf sb = STRBUF_INIT;
int cflags = REG_NEWLINE | REG_ICASE;
basic_regex_quote_buf(&sb, needle);
regcomp_or_die(&regex, sb.buf, cflags);
strbuf_release(&sb);
regexp = &regex;
} else {
kws = kwsalloc(DIFF_OPT_TST(o, PICKAXE_IGNORE_CASE)
? tolower_trans_tbl : NULL);
kwsincr(kws, needle, strlen(needle));
kwsprep(kws);
}
/* Might want to warn when both S and G are on; I don't care... */
pickaxe(&diff_queued_diff, o, regexp, kws,
(opts & DIFF_PICKAXE_KIND_G) ? diff_grep : has_changes);
if (regexp)
regfree(regexp);
else
kwsfree(kws);
return;
}