firmware-utils: bcm4908img: find cferom size

It's important for modifying / extracting firmware content. cferom is
optional image content at the file beginning.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

diff --git a/tools/firmware-utils/src/bcm4908img.c b/tools/firmware-utils/src/bcm4908img.c
index 56a790423b7e6ad5c8c8108f4272b487b0a89e66..b04916443b6b980bf91d39b573a61cc3c5d330a1 100644 (file)
--- a/tools/firmware-utils/src/bcm4908img.c
+++ b/tools/firmware-utils/src/bcm4908img.c
@@ -22,11 +22,19 @@
 #define le32_to_cpu(x) bswap_32(x)
 #define cpu_to_be32(x) (x)
 #define be32_to_cpu(x) (x)
+#define cpu_to_le16(x) bswap_16(x)
+#define le16_to_cpu(x) bswap_16(x)
+#define cpu_to_be16(x) (x)
+#define be16_to_cpu(x) (x)
 #elif __BYTE_ORDER == __LITTLE_ENDIAN
 #define cpu_to_le32(x) (x)
 #define le32_to_cpu(x) (x)
 #define cpu_to_be32(x) bswap_32(x)
 #define be32_to_cpu(x) bswap_32(x)
+#define cpu_to_le16(x) (x)
+#define le16_to_cpu(x) (x)
+#define cpu_to_be16(x) bswap_16(x)
+#define be16_to_cpu(x) bswap_16(x)
 #else
 #error "Unsupported endianness"
 #endif
@@ -57,6 +65,7 @@ struct bcm4908img_tail {
 struct bcm4908img_info {
        size_t file_size;
        size_t vendor_header_size;      /* Vendor header size */
+       size_t cferom_size;
        uint32_t crc32;                 /* Calculated checksum */
        struct bcm4908img_tail tail;
 };
@@ -203,6 +212,7 @@ static int bcm4908img_parse(FILE *fp, struct bcm4908img_info *info) {
        struct chk_header *chk;
        struct stat st;
        uint8_t buf[1024];
+       uint16_t tmp16;
        size_t length;
        size_t bytes;
        int err = 0;
@@ -229,6 +239,26 @@ static int bcm4908img_parse(FILE *fp, struct bcm4908img_info *info) {
        if (be32_to_cpu(chk->magic) == 0x2a23245e)
                info->vendor_header_size = be32_to_cpu(chk->header_len);
 
+       /* Sizes */
+
+       for (; info->vendor_header_size + info->cferom_size <= info->file_size; info->cferom_size += 0x20000) {
+               if (fseek(fp, info->vendor_header_size + info->cferom_size, SEEK_SET)) {
+                       err = -errno;
+                       fprintf(stderr, "Failed to fseek to the 0x%zx\n", info->cferom_size);
+                       return err;
+               }
+               if (fread(&tmp16, 1, sizeof(tmp16), fp) != sizeof(tmp16)) {
+                       fprintf(stderr, "Failed to read while looking for JFFS2\n");
+                       return -EIO;
+               }
+               if (be16_to_cpu(tmp16) == 0x8519)
+                       break;
+       }
+       if (info->vendor_header_size + info->cferom_size >= info->file_size) {
+               fprintf(stderr, "Failed to find cferom size (no bootfs found)\n");
+               return -EPROTO;
+       }
+
        /* CRC32 */
 
        fseek(fp, info->vendor_header_size, SEEK_SET);
@@ -294,6 +324,7 @@ static int bcm4908img_info(int argc, char **argv) {
        }
 
        printf("Vendor header length:\t%zu\n", info.vendor_header_size);
+       printf("cferom size:\t0x%zx\n", info.cferom_size);
        printf("Checksum:\t0x%08x\n", info.crc32);
 
 err_close: