@matheusbsbs / matheus-bagliano / commits / 75a9549047

avoid segfaults on parse_object failure

Many call-sites of parse_object assume that they will get a non-NULL return value; this is not the case if we encounter an error while parsing the object. This patch adds a wrapper function around parse_object that handles dying automatically, and uses it anywhere we immediately try to access the return value as a non-NULL pointer (i.e., anywhere that we would currently segfault). This wrapper may also be useful in other places. The most obvious one is code like: o = parse_object(sha1); if (!o) die(...); However, these should not be mechanically converted to parse_object_or_die, as the die message is sometimes customized. Later patches can address these sites on a case-by-case basis. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed Mar 17, 2013 at 04:22 UTC 75a95490474ab6e991cbbbd10d980498a9109648

4 files changed +26 -5

bundle.c

+3 -3

@@ -279,12 +279,12 @@ int create_bundle(struct bundle_header *header, const char *path,

279 if (buf.len > 0 && buf.buf[0] == '-') {

280 write_or_die(bundle_fd, buf.buf, buf.len);

281 if (!get_sha1_hex(buf.buf + 1, sha1)) {

282 - struct object *object = parse_object(sha1);

282 + struct object *object = parse_object_or_die(sha1, buf.buf);

283 object->flags |= UNINTERESTING;

284 add_pending_object(&revs, object, xstrdup(buf.buf));

285 }

286 } else if (!get_sha1_hex(buf.buf, sha1)) {

287 - struct object *object = parse_object(sha1);

287 + struct object *object = parse_object_or_die(sha1, buf.buf);

288 object->flags |= SHOWN;

289 }

290 }

@@ -361,7 +361,7 @@ int create_bundle(struct bundle_header *header, const char *path,

361 * end up triggering "empty bundle"

362 * error.

363 */

364 - obj = parse_object(sha1);

364 + obj = parse_object_or_die(sha1, e->name);

365 obj->flags |= SHOWN;

366 add_pending_object(&revs, obj, e->name);

367 }

object.c

+10

@@ -185,6 +185,16 @@ struct object *parse_object_buffer(const unsigned char *sha1, enum object_type t

185 return obj;

186 }

187

188 +struct object *parse_object_or_die(const unsigned char *sha1,

189 + const char *name)

190 +{

191 + struct object *o = parse_object(sha1);

192 + if (o)

193 + return o;

194 +

195 + die(_("unable to parse object: %s"), name ? name : sha1_to_hex(sha1));

196 +}

197 +

198 struct object *parse_object(const unsigned char *sha1)

199 {

200 unsigned long size;

object.h

+12 -1

@@ -54,9 +54,20 @@ struct object *lookup_object(const unsigned char *sha1);

55 extern void *create_object(const unsigned char *sha1, int type, void *obj);

57 -/** Returns the object, having parsed it to find out what it is. **/

57 +/*

58 + * Returns the object, having parsed it to find out what it is.

59 + *

60 + * Returns NULL if the object is missing or corrupt.

61 + */

62 struct object *parse_object(const unsigned char *sha1);

64 +/*

65 + * Like parse_object, but will die() instead of returning NULL. If the

66 + * "name" parameter is not NULL, it is included in the error message

67 + * (otherwise, the sha1 hex is given).

68 + */

69 +struct object *parse_object_or_die(const unsigned char *sha1, const char *name);

70 +

71 /* Given the result of read_sha1_file(), returns the object after

72 * parsing it. eaten_p indicates if the object has a borrowed copy

73 * of buffer and the caller should not free() it.

pack-refs.c

+1 -1

@@ -40,7 +40,7 @@ static int handle_one_ref(const char *path, const unsigned char *sha1,

41 fprintf(cb->refs_file, "%s %s\n", sha1_to_hex(sha1), path);

42 if (is_tag_ref) {

43 - struct object *o = parse_object(sha1);

43 + struct object *o = parse_object_or_die(sha1, path);

44 if (o->type == OBJ_TAG) {

45 o = deref_tag(o, path, 0);

46 if (o)