Change in coreboot[master]: util/cbfstool: Add "expand" command to make CBFS span an fmap region

[Patrick Georgi (Code Review)]

Patrick Georgi has uploaded this change for review. ( https://review.coreboot.org/21598

Change subject: util/cbfstool: Add "expand" command to make CBFS span an fmap region
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util/cbfstool: Add "expand" command to make CBFS span an fmap region

vboot images come with multiple regions carrying CBFS file systems. To
expedite hashing (from slow flash memory), the FW_MAIN_* regions are
truncated since they typically have pretty large unused space at the
end that is of no interest.
For test purposes it can be useful to re-engage that space, so add a
command that creates a new empty file entry covering that area (except
for the last 4 bytes for the master header pointer, as usual).

BUG=b:65853903
BRANCH=none
TEST=`cbfstool test.bin expand -r FW_MAIN_A` creates a new empty file of
the expected size on a Chrome OS firmware image.

Change-Id: I160c8529ce4bfcc28685166b6d9035ade4f6f1d1
Signed-off-by: Patrick Georgi 
---
M util/cbfstool/cbfs_image.c
M util/cbfstool/cbfs_image.h
M util/cbfstool/cbfstool.c
3 files changed, 61 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/98/21598/1

diff --git a/util/cbfstool/cbfs_image.c b/util/cbfstool/cbfs_image.c
index 1f4b49a..e3bc624 100644
--- a/util/cbfstool/cbfs_image.c
+++ b/util/cbfstool/cbfs_image.c
@@ -442,6 +442,41 @@
    return 0;
 }

+int cbfs_expand_to_region(struct buffer *region)
+{
+	struct cbfs_image image;
+	memset(&image, 0, sizeof(image));
+	if (cbfs_image_from_buffer(&image, region, 0)) {
+		ERROR("reading CBFS failed!\n");
+		return 1;
+	}
+
+	uint32_t region_sz = buffer_size(region);
+
+	struct cbfs_file *entry;
+	for (entry = buffer_get(region);
+	     entry && cbfs_is_valid_entry(&image, entry);
+	     entry = cbfs_find_next_entry(&image, entry)) {
+	     /* just iterate through */
+	}
+
+	/* entry now points to the first aligned address after the last valid
+	 * file header. That's either outside the image or exactly the place
+	 * where we need to create a new file.
+	 */
+	int last_entry_size = region_sz - ((void *)entry - buffer_get(region))
+		- cbfs_calculate_file_header_size("") - sizeof(int32_t);
+
+	if (last_entry_size > 0) {
+		cbfs_create_empty_entry(entry, CBFS_COMPONENT_NULL,
+			last_entry_size, "");
+		/* If the last entry was an empty file, merge them. */
+		cbfs_walk(&image, cbfs_merge_empty_entry, NULL);
+	}
+
+	return 0;
+}
+
 static size_t cbfs_file_entry_metadata_size(const struct cbfs_file *f)
 {
    return ntohl(f->offset);
diff --git a/util/cbfstool/cbfs_image.h b/util/cbfstool/cbfs_image.h
index 0d7877a..1bd74ce 100644
--- a/util/cbfstool/cbfs_image.h
+++ b/util/cbfstool/cbfs_image.h
@@ -80,6 +80,10 @@
  * beginning of the image. Returns 0 on success, otherwise non-zero.  */
 int cbfs_compact_instance(struct cbfs_image *image);

+/* Expand a CBFS image inside an fmap region to the entire region's space.
+   Returns 0 on success, otherwise non-zero. */
+int cbfs_expand_to_region(struct buffer *region);
+
 /* Releases the CBFS image. Returns 0 on success, otherwise non-zero. */
 int cbfs_image_delete(struct cbfs_image *image);

diff --git a/util/cbfstool/cbfstool.c b/util/cbfstool/cbfstool.c
index cc31751..9925358 100644
--- a/util/cbfstool/cbfstool.c
+++ b/util/cbfstool/cbfstool.c
@@ -1107,6 +1107,25 @@
    return cbfs_compact_instance(&image);
 }

+static int cbfs_expand(void)
+{
+	struct buffer src_buf;
+
+	if (!param.region_name) {
+		ERROR("You need to specify -r/--fmap-regions.\n");
+		return 1;
+	}
+
+	/* Obtain the source region. */
+	if (!partitioned_file_read_region(&src_buf, param.image_file,
+						param.region_name)) {
+		ERROR("Region not found in image: %s\n", param.source_region);
+		return 1;
+	}
+
+	return cbfs_expand_to_region(param.image_region);
+}
+
 static const struct command commands[] = {
    {"add", "H:r:f:n:t:c:b:a:yvA:gh?", cbfs_add, true, true},
    {"add-flat-binary", "H:r:f:n:l:e:c:b:vA:gh?", cbfs_add_flat_binary,
@@ -1127,6 +1146,7 @@
    {"remove", "H:r:n:vh?", cbfs_remove, true, true},
    {"update-fit", "H:r:n:x:vh?", cbfs_update_fit, true, true},
    {"write", "r:f:i:Fudvh?", cbfs_write, true, true},
+	{"expand", "r:h?", cbfs_expand, true, true},
 };

static struct option long_options[] = {
@@ -1276,6 +1296,8 @@
    		"Write file into same-size [or larger] raw region\n"
         " read [-r fmap-region] -f file                               "
    		"Extract raw region contents into binary file\n"
+	     " expand [-r fmap-region]                                     "
+			"Expand CBFS to span entire region\n"
         " update-fit [-r image,regions] -n MICROCODE_BLOB_NAME \\n"
         "        -x EMTPY_FIT_ENTRIES                                 "
    		"Updates the FIT table with microcode entries\n"