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![Martin Ågren](/assets/img/avatar_default.png)
It is apparently undefined behavior to call `regfree()` on a regex where `regcomp()` failed. The language in [1] is a bit muddy, at least to me, but the clearest hint is this (`preg` is the `regex_t *`): Upon successful completion, the regcomp() function shall return 0. Otherwise, it shall return an integer value indicating an error as described in <regex.h>, and the content of preg is undefined. Funnily enough, there is also the `regerror()` function which should be given a pointer to such a "failed" `regex_t` -- the content of which would supposedly be undefined -- and which may investigate it to come up with a detailed error message. In any case, the example in that document shows how `regfree()` is not called after `regcomp()` fails. We have quite a few users of this API and most get this right. These three users do not. Several implementations can handle this just fine [2] and these code paths supposedly have not wreaked havoc or we'd have heard about it. (These are all in code paths where git got bad input and is just about to die anyway.) But let's just avoid the issue altogether. [1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/regcomp.html [2] https://www.redhat.com/archives/libvir-list/2013-September/msg00262.html Researched-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-byi Martin Ågren <martin.agren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
262 lines
6.3 KiB
C
262 lines
6.3 KiB
C
/*
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* Copyright (C) 2005 Junio C Hamano
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* Copyright (C) 2010 Google Inc.
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*/
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#include "cache.h"
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#include "diff.h"
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#include "diffcore.h"
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#include "xdiff-interface.h"
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#include "kwset.h"
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#include "commit.h"
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#include "quote.h"
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typedef int (*pickaxe_fn)(mmfile_t *one, mmfile_t *two,
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struct diff_options *o,
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regex_t *regexp, kwset_t kws);
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struct diffgrep_cb {
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regex_t *regexp;
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int hit;
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};
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static void diffgrep_consume(void *priv, char *line, unsigned long len)
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{
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struct diffgrep_cb *data = priv;
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regmatch_t regmatch;
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if (line[0] != '+' && line[0] != '-')
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return;
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if (data->hit)
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/*
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* NEEDSWORK: we should have a way to terminate the
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* caller early.
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*/
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return;
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data->hit = !regexec_buf(data->regexp, line + 1, len - 1, 1,
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®match, 0);
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}
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static int diff_grep(mmfile_t *one, mmfile_t *two,
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struct diff_options *o,
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regex_t *regexp, kwset_t kws)
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{
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regmatch_t regmatch;
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struct diffgrep_cb ecbdata;
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xpparam_t xpp;
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xdemitconf_t xecfg;
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if (!one)
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return !regexec_buf(regexp, two->ptr, two->size,
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1, ®match, 0);
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if (!two)
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return !regexec_buf(regexp, one->ptr, one->size,
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1, ®match, 0);
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/*
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* We have both sides; need to run textual diff and see if
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* the pattern appears on added/deleted lines.
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*/
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memset(&xpp, 0, sizeof(xpp));
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memset(&xecfg, 0, sizeof(xecfg));
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ecbdata.regexp = regexp;
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ecbdata.hit = 0;
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xecfg.ctxlen = o->context;
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xecfg.interhunkctxlen = o->interhunkcontext;
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if (xdi_diff_outf(one, two, diffgrep_consume, &ecbdata, &xpp, &xecfg))
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return 0;
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return ecbdata.hit;
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}
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static unsigned int contains(mmfile_t *mf, regex_t *regexp, kwset_t kws)
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{
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unsigned int cnt;
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unsigned long sz;
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const char *data;
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sz = mf->size;
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data = mf->ptr;
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cnt = 0;
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if (regexp) {
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regmatch_t regmatch;
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int flags = 0;
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while (sz && *data &&
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!regexec_buf(regexp, data, sz, 1, ®match, flags)) {
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flags |= REG_NOTBOL;
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data += regmatch.rm_eo;
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sz -= regmatch.rm_eo;
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if (sz && *data && regmatch.rm_so == regmatch.rm_eo) {
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data++;
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sz--;
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}
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cnt++;
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}
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} else { /* Classic exact string match */
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while (sz) {
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struct kwsmatch kwsm;
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size_t offset = kwsexec(kws, data, sz, &kwsm);
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if (offset == -1)
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break;
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sz -= offset + kwsm.size[0];
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data += offset + kwsm.size[0];
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cnt++;
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}
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}
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return cnt;
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}
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static int has_changes(mmfile_t *one, mmfile_t *two,
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struct diff_options *o,
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regex_t *regexp, kwset_t kws)
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{
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unsigned int one_contains = one ? contains(one, regexp, kws) : 0;
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unsigned int two_contains = two ? contains(two, regexp, kws) : 0;
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return one_contains != two_contains;
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}
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static int pickaxe_match(struct diff_filepair *p, struct diff_options *o,
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regex_t *regexp, kwset_t kws, pickaxe_fn fn)
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{
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struct userdiff_driver *textconv_one = NULL;
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struct userdiff_driver *textconv_two = NULL;
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mmfile_t mf1, mf2;
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int ret;
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/* ignore unmerged */
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if (!DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two))
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return 0;
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if (o->objfind) {
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return (DIFF_FILE_VALID(p->one) &&
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oidset_contains(o->objfind, &p->one->oid)) ||
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(DIFF_FILE_VALID(p->two) &&
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oidset_contains(o->objfind, &p->two->oid));
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}
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if (!o->pickaxe[0])
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return 0;
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if (o->flags.allow_textconv) {
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textconv_one = get_textconv(p->one);
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textconv_two = get_textconv(p->two);
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}
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/*
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* If we have an unmodified pair, we know that the count will be the
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* same and don't even have to load the blobs. Unless textconv is in
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* play, _and_ we are using two different textconv filters (e.g.,
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* because a pair is an exact rename with different textconv attributes
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* for each side, which might generate different content).
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*/
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if (textconv_one == textconv_two && diff_unmodified_pair(p))
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return 0;
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mf1.size = fill_textconv(textconv_one, p->one, &mf1.ptr);
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mf2.size = fill_textconv(textconv_two, p->two, &mf2.ptr);
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ret = fn(DIFF_FILE_VALID(p->one) ? &mf1 : NULL,
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DIFF_FILE_VALID(p->two) ? &mf2 : NULL,
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o, regexp, kws);
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if (textconv_one)
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free(mf1.ptr);
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if (textconv_two)
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free(mf2.ptr);
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diff_free_filespec_data(p->one);
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diff_free_filespec_data(p->two);
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return ret;
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}
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static void pickaxe(struct diff_queue_struct *q, struct diff_options *o,
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regex_t *regexp, kwset_t kws, pickaxe_fn fn)
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{
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int i;
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struct diff_queue_struct outq;
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DIFF_QUEUE_CLEAR(&outq);
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if (o->pickaxe_opts & DIFF_PICKAXE_ALL) {
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/* Showing the whole changeset if needle exists */
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for (i = 0; i < q->nr; i++) {
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struct diff_filepair *p = q->queue[i];
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if (pickaxe_match(p, o, regexp, kws, fn))
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return; /* do not munge the queue */
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}
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/*
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* Otherwise we will clear the whole queue by copying
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* the empty outq at the end of this function, but
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* first clear the current entries in the queue.
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*/
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for (i = 0; i < q->nr; i++)
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diff_free_filepair(q->queue[i]);
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} else {
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/* Showing only the filepairs that has the needle */
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for (i = 0; i < q->nr; i++) {
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struct diff_filepair *p = q->queue[i];
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if (pickaxe_match(p, o, regexp, kws, fn))
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diff_q(&outq, p);
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else
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diff_free_filepair(p);
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}
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}
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free(q->queue);
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*q = outq;
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}
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static void regcomp_or_die(regex_t *regex, const char *needle, int cflags)
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{
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int err = regcomp(regex, needle, cflags);
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if (err) {
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/* The POSIX.2 people are surely sick */
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char errbuf[1024];
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regerror(err, regex, errbuf, 1024);
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die("invalid regex: %s", errbuf);
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}
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}
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void diffcore_pickaxe(struct diff_options *o)
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{
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const char *needle = o->pickaxe;
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int opts = o->pickaxe_opts;
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regex_t regex, *regexp = NULL;
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kwset_t kws = NULL;
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if (opts & (DIFF_PICKAXE_REGEX | DIFF_PICKAXE_KIND_G)) {
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int cflags = REG_EXTENDED | REG_NEWLINE;
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if (o->pickaxe_opts & DIFF_PICKAXE_IGNORE_CASE)
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cflags |= REG_ICASE;
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regcomp_or_die(®ex, needle, cflags);
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regexp = ®ex;
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} else if (opts & DIFF_PICKAXE_KIND_S) {
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if (o->pickaxe_opts & DIFF_PICKAXE_IGNORE_CASE &&
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has_non_ascii(needle)) {
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struct strbuf sb = STRBUF_INIT;
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int cflags = REG_NEWLINE | REG_ICASE;
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basic_regex_quote_buf(&sb, needle);
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regcomp_or_die(®ex, sb.buf, cflags);
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strbuf_release(&sb);
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regexp = ®ex;
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} else {
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kws = kwsalloc(o->pickaxe_opts & DIFF_PICKAXE_IGNORE_CASE
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? tolower_trans_tbl : NULL);
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kwsincr(kws, needle, strlen(needle));
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kwsprep(kws);
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}
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}
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pickaxe(&diff_queued_diff, o, regexp, kws,
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(opts & DIFF_PICKAXE_KIND_G) ? diff_grep : has_changes);
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if (regexp)
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regfree(regexp);
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if (kws)
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kwsfree(kws);
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return;
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}
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