cbfstool: add unprocessed flag for file exporting

Add an unprocessed flag (-U) which modifies how files are exported.
In the case of a compressed raw file, extract without decompressing.
In the case of a stage or payload, extract without decompressing or
converting to an ELF.

This can be useful for verifying the integrity of a stage or payload,
since converting to an ELF may not be a deterministic process on
different platforms or coreboot versions.

BUG=b:111577108
TEST=USE=cb_legacy_tianocore emerge-eve edk2 coreboot-utils chromeos-bootimage
     cd /build/eve/firmware
     /build/eve/usr/bin/cbfstool image.bin extract -r RW_LEGACY \
       -n payload -f /tmp/payload_1 -U
     START=$((16#`xxd -s 20 -l 4 -p tianocore.cbfs`))
     SIZE=$((16#`xxd -s 8 -l 4 -p tianocore.cbfs`))
     dd if=tianocore.cbfs skip=$START count=$SIZE bs=1 > /tmp/payload_2
     diff /tmp/payload_1 /tmp/payload_2
     rm /tmp/payload_1 /tmp/payload_2

Change-Id: I351d471d699daedd51adf4a860661877f25607e6
Signed-off-by: Joel Kitching <kitching@chromium.org>
Reviewed-on: https://review.coreboot.org/29616
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Julius Werner <jwerner@chromium.org>

1 files changed, 34 insertions, 17 deletions

diff --git a/util/cbfstool/cbfs_image.c b/util/cbfstool/cbfs_image.c
index c84eaab48d28..3c5d29cbea8e 100644
--- a/util/cbfstool/cbfs_image.c
+++ b/util/cbfstool/cbfs_image.c
@@ -1286,7 +1286,7 @@ out:
 }
 
 int cbfs_export_entry(struct cbfs_image *image, const char *entry_name,
-		      const char *filename, uint32_t arch)
+		      const char *filename, uint32_t arch, bool do_processing)
 {
 	struct cbfs_file *entry = cbfs_get_entry(image, entry_name);
 	struct buffer buffer;
@@ -1295,26 +1295,37 @@ int cbfs_export_entry(struct cbfs_image *image, const char *entry_name,
 		return -1;
 	}
 
+	unsigned int compressed_size = ntohl(entry->len);
 	unsigned int decompressed_size = 0;
 	unsigned int compression = cbfs_file_get_compression_info(entry,
 		&decompressed_size);
+	unsigned int buffer_size;
+	decomp_func_ptr decompress;
 
-	decomp_func_ptr decompress = decompression_function(compression);
-	if (!decompress) {
-		ERROR("looking up decompression routine failed\n");
-		return -1;
+	if (do_processing) {
+		decompress = decompression_function(compression);
+		if (!decompress) {
+			ERROR("looking up decompression routine failed\n");
+			return -1;
+		}
+		buffer_size = decompressed_size;
+	} else {
+		/* Force nop decompression */
+		decompress = decompression_function(CBFS_COMPRESS_NONE);
+		buffer_size = compressed_size;
 	}
 
-	LOG("Found file %.30s at 0x%x, type %.12s, size %d\n",
+	LOG("Found file %.30s at 0x%x, type %.12s, compressed %d, size %d\n",
 	    entry_name, cbfs_get_entry_addr(image, entry),
-	    get_cbfs_entry_type_name(ntohl(entry->type)), decompressed_size);
+	    get_cbfs_entry_type_name(ntohl(entry->type)), compressed_size,
+	    decompressed_size);
 
 	buffer_init(&buffer, strdup("(cbfs_export_entry)"), NULL, 0);
+	buffer.data = malloc(buffer_size);
+	buffer.size = buffer_size;
 
-	buffer.data = malloc(decompressed_size);
-	buffer.size = decompressed_size;
-	if (decompress(CBFS_SUBHEADER(entry), ntohl(entry->len),
-		buffer.data, buffer.size, NULL)) {
+	if (decompress(CBFS_SUBHEADER(entry), compressed_size,
+		       buffer.data, buffer.size, NULL)) {
 		ERROR("decompression failed for %s\n", entry_name);
 		buffer_delete(&buffer);
 		return -1;
@@ -1326,13 +1337,19 @@ int cbfs_export_entry(struct cbfs_image *image, const char *entry_name,
 	 * one has to do a second pass for stages to potentially decompress
 	 * the stage data to make it more meaningful.
 	 */
-	if (ntohl(entry->type) == CBFS_COMPONENT_STAGE) {
-		if (cbfs_stage_make_elf(&buffer, arch)) {
-			buffer_delete(&buffer);
-			return -1;
+	if (do_processing) {
+		int (*make_elf)(struct buffer *, uint32_t) = NULL;
+		switch (ntohl(entry->type)) {
+		case CBFS_COMPONENT_STAGE:
+			make_elf = cbfs_stage_make_elf;
+			break;
+		case CBFS_COMPONENT_SELF:
+			make_elf = cbfs_payload_make_elf;
+			break;
 		}
-	} else if (ntohl(entry->type) == CBFS_COMPONENT_SELF) {
-		if (cbfs_payload_make_elf(&buffer, arch)) {
+		if (make_elf && make_elf(&buffer, arch)) {
+			ERROR("Failed to write %s into %s.\n",
+			      entry_name, filename);
 			buffer_delete(&buffer);
 			return -1;
 		}