tag: allow lookup_tag to handle arbitrary repositories

diff --git a/ewah/ewah_io.c b/ewah/ewah_io.c
index bed1994551cd03532fe56913b0e27343834c805f..33c08c40f896f32d9a1c251c1456755e949d91bd 100644 (file)
--- a/ewah/ewah_io.c
+++ b/ewah/ewah_io.c
@@ -122,16 +122,23 @@ int ewah_serialize_strbuf(struct ewah_bitmap *self, struct strbuf *sb)
        return ewah_serialize_to(self, write_strbuf, sb);
 }
 
-int ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
+ssize_t ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
 {
        const uint8_t *ptr = map;
+       size_t data_len;
        size_t i;
 
+       if (len < sizeof(uint32_t))
+               return error("corrupt ewah bitmap: eof before bit size");
        self->bit_size = get_be32(ptr);
        ptr += sizeof(uint32_t);
+       len -= sizeof(uint32_t);
 
+       if (len < sizeof(uint32_t))
+               return error("corrupt ewah bitmap: eof before length");
        self->buffer_size = self->alloc_size = get_be32(ptr);
        ptr += sizeof(uint32_t);
+       len -= sizeof(uint32_t);
 
        REALLOC_ARRAY(self->buffer, self->alloc_size);
 
@@ -141,15 +148,25 @@ int ewah_read_mmap(struct ewah_bitmap *self, const void *map, size_t len)
         * the endianness conversion in a separate pass to ensure
         * we're loading 8-byte aligned words.
         */
-       memcpy(self->buffer, ptr, self->buffer_size * sizeof(eword_t));
-       ptr += self->buffer_size * sizeof(eword_t);
+       data_len = st_mult(self->buffer_size, sizeof(eword_t));
+       if (len < data_len)
+               return error("corrupt ewah bitmap: eof in data "
+                            "(%"PRIuMAX" bytes short)",
+                            (uintmax_t)(data_len - len));
+       memcpy(self->buffer, ptr, data_len);
+       ptr += data_len;
+       len -= data_len;
 
        for (i = 0; i < self->buffer_size; ++i)
                self->buffer[i] = ntohll(self->buffer[i]);
 
+       if (len < sizeof(uint32_t))
+               return error("corrupt ewah bitmap: eof before rlw");
        self->rlw = self->buffer + get_be32(ptr);
+       ptr += sizeof(uint32_t);
+       len -= sizeof(uint32_t);
 
-       return (3 * 4) + (self->buffer_size * 8);
+       return ptr - (const uint8_t *)map;
 }
 
 int ewah_deserialize(struct ewah_bitmap *self, int fd)