[PATCH 1/2] bcm4908img: store offset of tail data

[Rafał Miłecki]

From: Rafał Miłecki <ra...@milecki.pl>

This simplifies some operations as it doesn't have to be caculated over
and over. It will also allow adding support for more vendor formats.

Signed-off-by: Rafał Miłecki <ra...@milecki.pl>
---
 package/utils/bcm4908img/Makefile         |  2 +-
 package/utils/bcm4908img/src/bcm4908img.c | 23 +++++++++++++----------
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/package/utils/bcm4908img/Makefile 
b/package/utils/bcm4908img/Makefile
index c18ac958f8..ff504a8078 100644
--- a/package/utils/bcm4908img/Makefile
+++ b/package/utils/bcm4908img/Makefile
@@ -3,7 +3,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=bcm4908img
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_FLAGS:=nonshared
 
diff --git a/package/utils/bcm4908img/src/bcm4908img.c 
b/package/utils/bcm4908img/src/bcm4908img.c
index 402d317190..f2023ced9f 100644
--- a/package/utils/bcm4908img/src/bcm4908img.c
+++ b/package/utils/bcm4908img/src/bcm4908img.c
@@ -79,11 +79,11 @@ struct bcm4908img_tail {
  * 6. BCM4908 tail
  */
 struct bcm4908img_info {
-       size_t file_size;
        size_t cferom_offset;
        size_t bootfs_offset;
        size_t padding_offset;
        size_t rootfs_offset;
+       size_t tail_offset;
        uint32_t crc32;                 /* Calculated checksum */
        struct bcm4908img_tail tail;
 };
@@ -219,7 +219,7 @@ static int bcm4908img_calc_crc32(FILE *fp, struct 
bcm4908img_info *info) {
        fseek(fp, info->cferom_offset, SEEK_SET);
 
        info->crc32 = 0xffffffff;
-       length = info->file_size - info->cferom_offset - sizeof(struct 
bcm4908img_tail);
+       length = info->tail_offset - info->cferom_offset;
        while (length && (bytes = fread(buf, 1, bcm4908img_min(sizeof(buf), 
length), fp)) > 0) {
                info->crc32 = bcm4908img_crc32(info->crc32, buf, bytes);
                length -= bytes;
@@ -267,6 +267,7 @@ static int bcm4908img_parse(FILE *fp, struct 
bcm4908img_info *info) {
        struct chk_header *chk;
        struct stat st;
        uint8_t buf[1024];
+       size_t file_size;
        uint16_t tmp16;
        size_t length;
        size_t bytes;
@@ -281,7 +282,9 @@ static int bcm4908img_parse(FILE *fp, struct 
bcm4908img_info *info) {
                fprintf(stderr, "Failed to fstat: %d\n", err);
                return err;
        }
-       info->file_size = st.st_size;
+       file_size = st.st_size;
+
+       info->tail_offset = file_size - sizeof(*tail);
 
        /* Vendor formats */
 
@@ -297,7 +300,7 @@ static int bcm4908img_parse(FILE *fp, struct 
bcm4908img_info *info) {
        /* Offsets */
 
        for (info->bootfs_offset = info->cferom_offset;
-            info->bootfs_offset < info->file_size;
+            info->bootfs_offset < info->tail_offset;
             info->bootfs_offset += 0x20000) {
                if (fseek(fp, info->bootfs_offset, SEEK_SET)) {
                        err = -errno;
@@ -311,13 +314,13 @@ static int bcm4908img_parse(FILE *fp, struct 
bcm4908img_info *info) {
                if (be16_to_cpu(tmp16) == 0x8519)
                        break;
        }
-       if (info->bootfs_offset >= info->file_size) {
+       if (info->bootfs_offset >= info->tail_offset) {
                fprintf(stderr, "Failed to find bootfs offset\n");
                return -EPROTO;
        }
 
        for (info->rootfs_offset = info->bootfs_offset;
-            info->rootfs_offset < info->file_size;
+            info->rootfs_offset < info->tail_offset;
             info->rootfs_offset += 0x20000) {
                uint32_t *magic = (uint32_t *)&buf[0];
 
@@ -340,7 +343,7 @@ static int bcm4908img_parse(FILE *fp, struct 
bcm4908img_info *info) {
                if (be32_to_cpu(*magic) == UBI_EC_HDR_MAGIC)
                        break;
        }
-       if (info->rootfs_offset >= info->file_size) {
+       if (info->rootfs_offset >= info->tail_offset) {
                fprintf(stderr, "Failed to find rootfs offset\n");
                return -EPROTO;
        }
@@ -351,7 +354,7 @@ static int bcm4908img_parse(FILE *fp, struct 
bcm4908img_info *info) {
        fseek(fp, info->cferom_offset, SEEK_SET);
 
        info->crc32 = 0xffffffff;
-       length = info->file_size - info->cferom_offset - sizeof(*tail);
+       length = info->tail_offset - info->cferom_offset;
        while (length && (bytes = fread(buf, 1, bcm4908img_min(sizeof(buf), 
length), fp)) > 0) {
                info->crc32 = bcm4908img_crc32(info->crc32, buf, bytes);
                length -= bytes;
@@ -617,10 +620,10 @@ static int bcm4908img_extract(int argc, char **argv) {
                length = (info.padding_offset ? info.padding_offset : 
info.rootfs_offset) - offset;
        } else if (!strcmp(type, "rootfs")) {
                offset = info.rootfs_offset;
-               length = info.file_size - offset - sizeof(struct 
bcm4908img_tail);
+               length = info.tail_offset - offset;
        } else if (!strcmp(type, "firmware")) {
                offset = info.bootfs_offset;
-               length = info.file_size - offset - sizeof(struct 
bcm4908img_tail);
+               length = info.tail_offset - offset;
        } else {
                err = -EINVAL;
                fprintf(stderr, "Unsupported extract type: %s\n", type);
-- 
2.26.2


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