image-android-sparse: add option to fill holes with zeros

By default 'holes' are converted into "don't care" areas. This adds an
option to fill the area with zeros instead.

Signed-off-by: Michael Olbrich <[email protected]>

Author: michaelolbrich

Makefile.am

@@ -146,6 +146,7 @@ EXTRA_DIST += \
 	test/rauc.config \
 	test/sharness.sh \
 	test/sparse.config \
+	test/sparse-fill.config \
 	test/squashfs.config \
 	test/tar.config \
 	test/test.raucb.info.1 \

README.rst

@@ -251,6 +251,8 @@ Options:
 :block-size:		The granularity that the sparse image uses to
 			find "don't care" or "fill" blocks. The supported
 			block sizes depend on the user. The default is 4k.
+:fill-holes:		If enabled, 'holes' are filled with zero instead of
+			"don't care". Disabled by default.
 
 cpio
 ****

genimage.h

@@ -175,6 +175,8 @@ struct extent {
 };
 
 int open_file(struct image *image, const char *filename, int extra_flags);
+int whole_file_exent(size_t size, struct extent **extents,
+		     size_t *extent_count);
 int map_file_extents(struct image *image, const char *filename, int fd,
 		     size_t size, struct extent **extents, size_t *extent_count);
 int is_block_device(const char *filename);

image-android-sparse.c

@@ -28,6 +28,7 @@
 
 struct sparse {
 	uint32_t block_size;
+	cfg_bool_t fill_holes;
 };
 
 struct sparse_header {
@@ -147,9 +148,13 @@ static int android_sparse_generate(struct image *image)
 	block_count = (s.st_size - 1 + sparse->block_size) / sparse->block_size;
 	header.output_blocks = block_count;
 
-	ret = map_file_extents(inimage, infile, in_fd, s.st_size, &extents, &extent_count);
-	if (ret < 0)
-		goto out;
+	if (sparse->fill_holes)
+		whole_file_exent(s.st_size, &extents, &extent_count);
+	else {
+		ret = map_file_extents(inimage, infile, in_fd, s.st_size, &extents, &extent_count);
+		if (ret < 0)
+			goto out;
+	}
 
 	/* The extents may have a different granularity than the chosen block size.
 	   So all start and end of all extents must be aligned accordingly. The
@@ -391,6 +396,7 @@ static int android_sparse_setup(struct image *image, cfg_t *cfg)
 			    sparse->block_size);
 		return -EINVAL;
 	}
+	sparse->fill_holes = cfg_getbool(cfg, "fill-holes");
 
 	image->handler_priv = sparse;
 	return 0;
@@ -399,6 +405,7 @@ static int android_sparse_setup(struct image *image, cfg_t *cfg)
 static cfg_opt_t android_sparse_opts[] = {
 	CFG_STR("image", NULL, CFGF_NONE),
 	CFG_STR("block-size", "4k", CFGF_NONE),
+	CFG_BOOL("fill-holes", cfg_false, CFGF_NONE),
 	CFG_END()
 };
 

test/misc.test

@@ -93,6 +93,17 @@ test_expect_success simg2img "android-sparse" "
 	simg2img images/test.sparse images/test.hdimage &&
 	simg2img images/interleaved.sparse input/interleaved &&
 	simg2img images/not-aligned.sparse input/not-aligned &&
+	md5sum -c md5sum &&
+
+	run_genimage sparse-fill.config &&
+	# simg2img will expand the partial block
+	truncate --size=12k input/not-aligned
+	md5sum images/test.hdimage input/interleaved input/not-aligned > md5sum &&
+	rm images/test.hdimage input/interleaved input/not-aligned &&
+	check_size_range images/interleaved.sparse 9732464 9732636 &&
+	simg2img images/test.sparse images/test.hdimage &&
+	simg2img images/interleaved.sparse input/interleaved &&
+	simg2img images/not-aligned.sparse input/not-aligned &&
 	md5sum -c md5sum
 "
 

util.c

@@ -398,8 +398,8 @@ int open_file(struct image *image, const char *filename, int extra_flags)
 }
 
 /* Build a file extent covering the whole file */
-static int whole_file_exent(size_t size, struct extent **extents,
-			    size_t *extent_count)
+int whole_file_exent(size_t size, struct extent **extents,
+		     size_t *extent_count)
 {
 	*extents = xzalloc(sizeof(struct extent));
 	(*extents)[0].start = 0;