libpayload: allow compression at file header level

Decompression is handled transparently within cbfs_get_file_content:

	const char *name = "foo.bmp";
	void *dst = cbfs_get_file_content(media, name, type, NULL);

To keep things consistent, a couple of API changes were necessary:
- cbfs_get_file_content always returns a copy of the data, even for
  uncompressed files. It's the callers responsibility to free the
  memory.
- same for cbfs_load_payload and cbfs_find_file.
- cbfs_load_optionrom doesn't take a "dest" argument anymore but always
  returns a copy of the data, for compressed and uncompressed files.
  Like with cbfs_get_file_content, the caller is responsible to free it.
  It also decompresses based on extended file attributes instead of the
  cbfs_optionrom subheader that libpayload specified but that (AFAIK)
  nobody ever used, given that there's not even tooling for that.

Change-Id: If959e3dff9b93c6ae45ec7358afcc7840bc17218
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: http://review.coreboot.org/10938
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)

1 files changed, 32 insertions, 1 deletions

diff --git a/payloads/libpayload/libcbfs/cbfs_core.c b/payloads/libpayload/libcbfs/cbfs_core.c
index 5541f0242d..5a46af8daa 100644
--- a/payloads/libpayload/libcbfs/cbfs_core.c
+++ b/payloads/libpayload/libcbfs/cbfs_core.c
@@ -210,7 +210,38 @@ void *cbfs_get_file_content(struct cbfs_media *media, const char *name,
 	if (sz)
 		*sz = ntohl(file->len);
 
-	return (void *)CBFS_SUBHEADER(file);
+	void *file_content = (void *)CBFS_SUBHEADER(file);
+
+	struct cbfs_file_attribute *attr = cbfs_file_first_attr(file);
+	while (attr) {
+		if (ntohl(attr->tag) == CBFS_FILE_ATTR_TAG_COMPRESSION)
+			break;
+		attr = cbfs_file_next_attr(file, attr);
+	}
+
+	int compression_algo = CBFS_COMPRESS_NONE;
+	if (attr) {
+		struct cbfs_file_attr_compression *comp =
+			(struct cbfs_file_attr_compression *)attr;
+		compression_algo = ntohl(comp->compression);
+		DEBUG("File '%s' is compressed (alg=%d)\n", compression_algo);
+		*sz = ntohl(comp->decompressed_size);
+	}
+
+	void *dst = malloc(*sz);
+	if (dst == NULL)
+		goto err;
+
+	if (!cbfs_decompress(compression_algo, file_content, dst, *sz))
+		goto err;
+
+	media->unmap(media, file);
+	return dst;
+
+err:
+	media->unmap(media, file);
+	free(dst);
+	return NULL;
 }
 
 struct cbfs_file_attribute *cbfs_file_first_attr(struct cbfs_file *file)