@@ -160,6 +160,14 @@ export_partdevice() {
return 1
}
+hex_le32_to_cpu() {
+ [ "$(echo 01 | hexdump -v -n 2 -e '/2 "%x"')" == "3031" ] && {
+ echo "${1:0:2}${1:8:2}${1:6:2}${1:4:2}${1:2:2}"
+ return
+ }
+ echo "$@"
+}
+
get_partitions() { # <device> <filename>
local disk="$1"
local filename="$2"
@@ -167,8 +175,8 @@ get_partitions() { # <device> <filename>
if [ -b "$disk" -o -f "$disk" ]; then
v "Reading partition table from $filename..."
- local magic="$(hexdump -v -n 2 -s 0x1FE -e '1/2 "0x%04X"' "$disk")"
- if [ "$magic" != 0xAA55 ]; then
+ local magic=$(dd if="$disk" bs=2 count=1 skip=255 2>/dev/null)
+ if [ "$magic" != $'\x55\xAA' ]; then
v "Invalid partition table on $disk"
exit
fi
@@ -179,9 +187,9 @@ get_partitions() { # <device> <filename>
for part in 1 2 3 4; do
set -- $(hexdump -v -n 12 -s "$((0x1B2 + $part * 16))" -e '3/4 "0x%08X "' "$disk")
- local type="$(($1 % 256))"
- local lba="$(($2))"
- local num="$(($3))"
+ local type="$(( $(hex_le32_to_cpu $1) % 256))"
+ local lba="$(( $(hex_le32_to_cpu $2) ))"
+ local num="$(( $(hex_le32_to_cpu $3) ))"
[ $type -gt 0 ] || continue
This patch fixes two issues with the current get_partitions() function. First: "Invalid partition table on $disk" will pop up on legitimate images on big endian system. This is because the little-endian representation of "55 AA" is assumed in the context of little-endian architectures. On these comparing it to the 16-bit word 0xAA55 does work as intented. Whereas on big-endian systems, this would have to be 0x55AA. This patch fixes the issue by replacing the integer conversion and value match check with just a string comparision. Second: The extraction of the type, start LBA and LBA num from the partition table has the same endianness issue. This has been fixed by using the new hex_le32_to_cpu() function. This function will translate the stored little-endian data to the correct byte-order if necessary. Signed-off-by: Christian Lamparter <chunkeey@gmail.com> --- I stumbled upon this bug, when I was porting over the x86's sysupgrade code to the PPC MyBook Live. I'm not entirely happy with this yet. I'm looking for a better way that could to without the hex_le32_to_cpu. Any ideas? --- package/base-files/files/lib/upgrade/common.sh | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)