cbfs: add cbfs_read()

Allow for reading from cbfs media without having a handle
to a non-CBFS_DEFAULT_MEDIA cbfs_media. In conjunction with
cbfs_locate_file() one can locate and cbfs_read() a file
without bringing the entire file through a potentially
temporary buffer (non-memory-mappable cbfs media platforms).

BUG=chrome-os-partner:29922
BRANCH=None
TEST=Built.

Original-Change-Id: Ib5d965334bce1267650fc23c9e9f496675cf8450
Original-Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/205991
Original-Reviewed-by: Furquan Shaikh <furquan@chromium.org>
(cherry picked from commit 85200f28863e5ea8888322f5787dc6de9a2999f0)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I25e3221beefd0155305ad63da6be9f47e756f7d0
Reviewed-on: http://review.coreboot.org/8181
Tested-by: build bot (Jenkins)
Reviewed-by: Furquan Shaikh <furquan@google.com>
This commit is contained in:
Aaron Durbin 2014-06-27 15:28:39 -05:00 committed by Marc Jones
parent b312b7f466
commit b3e0202fd4
2 changed files with 20 additions and 0 deletions

View File

@ -224,6 +224,10 @@ struct cbfs_media {
ssize_t cbfs_locate_file(struct cbfs_media *media, struct cbfs_file *file,
const char *name);
/* Read count bytes at offset into dest. Return number of bytes read. */
size_t cbfs_read(struct cbfs_media *media, void *dest, size_t offset,
size_t count);
/* returns pointer to a file entry inside CBFS or NULL */
struct cbfs_file *cbfs_get_file(struct cbfs_media *media, const char *name);

View File

@ -194,6 +194,22 @@ ssize_t cbfs_locate_file(struct cbfs_media *media, struct cbfs_file *file,
return -1;
}
size_t cbfs_read(struct cbfs_media *media, void *dest, size_t offset,
size_t count)
{
struct cbfs_media default_media;
size_t nread;
if (init_media(&media, &default_media))
return 0;
media->open(media);
nread = media->read(media, dest, offset, count);
media->close(media);
return nread;
}
struct cbfs_file *cbfs_get_file(struct cbfs_media *media, const char *name)
{
struct cbfs_media default_media;