reftable/blocksource: handle allocation failures

Handle allocation failures in the blocksource code.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pks-t

reftable/blocksource.c

@@ -30,6 +30,8 @@ static int strbuf_read_block(void *v, struct reftable_block *dest, uint64_t off,
 	struct strbuf *b = v;
 	assert(off + size <= b->len);
 	REFTABLE_CALLOC_ARRAY(dest->data, size);
+	if (!dest->data)
+		return -1;
 	memcpy(dest->data, b->buf + off, size);
 	dest->len = size;
 	return size;
@@ -98,27 +100,40 @@ int reftable_block_source_from_file(struct reftable_block_source *bs,
 {
 	struct file_block_source *p;
 	struct stat st;
-	int fd;
+	int fd, err;
 
 	fd = open(name, O_RDONLY);
 	if (fd < 0) {
 		if (errno == ENOENT)
 			return REFTABLE_NOT_EXIST_ERROR;
-		return -1;
+		err = -1;
+		goto out;
 	}
 
 	if (fstat(fd, &st) < 0) {
-		close(fd);
-		return REFTABLE_IO_ERROR;
+		err = REFTABLE_IO_ERROR;
+		goto out;
 	}
 
 	REFTABLE_CALLOC_ARRAY(p, 1);
+	if (!p) {
+		err = REFTABLE_OUT_OF_MEMORY_ERROR;
+		goto out;
+	}
+
 	p->size = st.st_size;
 	p->data = xmmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
-	close(fd);
 
 	assert(!bs->ops);
 	bs->ops = &file_vtable;
 	bs->arg = p;
+
+	err = 0;
+
+out:
+	if (fd >= 0)
+		close(fd);
+	if (err < 0)
+		reftable_free(p);
 	return 0;
 }