util/build-id: Return a pointer rather than copying the data

We're about to use the build-id as the starting point for another SHA1
hash in the Intel Vulkan driver, and returning a pointer is far more
convenient.

Reviewed-by: Chad Versace <chadversary@chromium.org>

src/intel/vulkan/anv_device.c

@@ -63,7 +63,7 @@ anv_device_get_cache_uuid(void *uuid)
    if (len < VK_UUID_SIZE)
       return false;
 
-   build_id_read(note, uuid, VK_UUID_SIZE);
+   memcpy(uuid, build_id_data(note), VK_UUID_SIZE);
    return true;
 }
 

src/util/build_id.c

@@ -107,11 +107,10 @@ build_id_length(const struct build_id_note *note)
    return note->nhdr.n_descsz;
 }
 
-void
-build_id_read(const struct build_id_note *note,
-              unsigned char *build_id, size_t n)
+const uint8_t *
+build_id_data(const struct build_id_note *note)
 {
-   memcpy(build_id, note->build_id, n);
+   return note->build_id;
 }
 
 #endif

src/util/build_id.h

@@ -31,8 +31,7 @@ build_id_find_nhdr(const char *filename);
 unsigned
 build_id_length(const struct build_id_note *note);
 
-void
-build_id_read(const struct build_id_note *note,
-              unsigned char *build_id, size_t n);
+const uint8_t *
+build_id_data(const struct build_id_note *note);
 
 #endif