util/cbfstool: Add "truncate" command

It does the opposite to "expand", removing a trailing empty file from
CBFS. It also returns the size of the CBFS post processing on stdout.

BUG=b:65853903
BRANCH=none
TEST=`cbfstool test.bin truncate -r FW_MAIN_A` removes the trailing
empty file in FW_MAIN_A. Without a trailing empty file, the region is
left alone (tested using COREBOOT which comes with a master header
pointer).

Change-Id: I0c747090813898539f3428936afa9d8459adee9c
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/21608
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
This commit is contained in:
Patrick Georgi
2017-09-20 11:59:18 +02:00
parent d6c0af6c54
commit 12631a4d1d
3 changed files with 63 additions and 0 deletions

View File

@@ -480,6 +480,44 @@ int cbfs_expand_to_region(struct buffer *region)
return 0;
}
int cbfs_truncate_space(struct buffer *region, uint32_t *size)
{
if (buffer_get(region) == NULL)
return 1;
struct cbfs_image image;
memset(&image, 0, sizeof(image));
if (cbfs_image_from_buffer(&image, region, 0)) {
ERROR("reading CBFS failed!\n");
return 1;
}
struct cbfs_file *entry, *trailer;
for (trailer = entry = buffer_get(region);
cbfs_is_valid_entry(&image, entry);
trailer = entry,
entry = cbfs_find_next_entry(&image, entry)) {
/* just iterate through */
}
/* trailer now points to the last valid CBFS entry's header.
* If that file is empty, remove it and report its header's offset as
* maximum size.
*/
if ((strlen(trailer->filename) != 0) &&
(trailer->type != htonl(CBFS_COMPONENT_NULL)) &&
(trailer->type != htonl(CBFS_COMPONENT_DELETED))) {
/* nothing to truncate. Return de-facto CBFS size in case it
* was already truncated. */
*size = (void *)entry - buffer_get(region);
return 0;
}
*size = (void *)trailer - buffer_get(region);
memset(trailer, 0xff, buffer_size(region) - *size);
return 0;
}
static size_t cbfs_file_entry_metadata_size(const struct cbfs_file *f)
{
return ntohl(f->offset);