Make the CBFS file lookup skip file data instead of brute-forcing

its way through it, looking for magic numbers.
For one, it should speed up file access, esp. with many entries,
but it also helps against false positives (eg. seabios, which
contains the magic number for its own CBFS support, which _might_
just be aligned properly)

Also avoid infinite loops and give up searching for new files for
invalid magic numbers.

Signed-off-by: Patrick Georgi <patrick.georgi@coresystems.de>
Acked-by: Stefan Reinauer <stepan@coresystems.de>


git-svn-id: svn://svn.coreboot.org/coreboot/trunk@4210 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

1 files changed, 13 insertions, 4 deletions

diff --git a/src/lib/cbfs.c b/src/lib/cbfs.c
index 11098b6b86..3a79502fbb 100644
--- a/src/lib/cbfs.c
+++ b/src/lib/cbfs.c
@@ -96,14 +96,23 @@ struct cbfs_file *cbfs_find(const char *name)
 		return NULL;
 	offset = 0 - ntohl(header->romsize) + ntohl(header->offset);
 
+	int align= ntohl(header->align);
+
 	while(1) {
 		struct cbfs_file *file = (struct cbfs_file *) offset;
-		if (cbfs_check_magic(file)) printk_info("Check %s\n", CBFS_NAME(file));
-		if (cbfs_check_magic(file) &&
-		    !strcmp(CBFS_NAME(file), name))
+		if (!cbfs_check_magic(file)) return NULL;
+		printk_info("Check %s\n", CBFS_NAME(file));
+		if (!strcmp(CBFS_NAME(file), name))
 			return file;
 
-		offset += ntohl(header->align);
+		int flen = ntohl(file->len);
+		int foffset = ntohl(file->offset);
+		printk_spew("CBFS: follow chain: %p + %x + %x + align -> ", offset, foffset, flen);
+
+		unsigned long oldoffset = offset;
+		offset = ALIGN(offset + foffset + flen, align);
+		printk_spew("%p\n", offset);
+		if (offset <= oldoffset) return NULL;
 
 		if (offset < 0xFFFFFFFF - ntohl(header->romsize))
 			return NULL;