blobutil/download: don't hardcode me.bin paths

Bruteforce it. Some executables are just using inno
archival but some are simple LZMA. This patch handles
both of them, and also the event where you have LZMA
compressed files (even LZMA compressed files within
LZMA compressed archives) within any inno/lzma compressed
executable.

It recursively scans inside a vendor update, to find
a me.bin files for neutering with me_cleaner.

This is in preparation for two new ports in Libreboot:

* HP EliteBook 8560w
* Apple MacBook Air 4,2 (2011)

This script can literally be used with multiple vendors now.
It is no longer specific just to Lenovo. I originally did
this and other recent commits to the file, as one big
commit, but I decided to split it all up into small commits.

resources/scripts/blobs/download

@@ -5,6 +5,9 @@
 # SPDX-FileCopyrightText: 2023 Leah Rowe <info@minifree.org>
 # SPDX-License-Identifier: GPL-3.0-only
 
+_7ztest="a"
+mecleaner="$(pwd)/me_cleaner/me_cleaner.py"
+me7updateparser="$(pwd)/resources/blobs/me7_update_parser.py"
 board="${1}"
 # A shorthand for each board, to avoid duplicating configs per flash size
 board_short=${board%%_*mb}
@@ -114,8 +117,6 @@ Download_me() {
 Fetch_update() {
 	printf "Fetching vendor update for board: `%s`\n" ${board}
 
-	_me_destination=${CONFIG_ME_BIN_PATH#../../}
-
 	if [ -z "${dl_url+x}" ]; then
 		printf "No vendor update specified for board: `%s`\n" ${board}
 		return 1
@@ -146,6 +147,8 @@ Vendor_checksum() {
 Extract_me(){
 	printf "Extracting neutered ME for ${board}\n"
 
+	_me_destination=${CONFIG_ME_BIN_PATH#../../}
+
 	if [ ! -d "${_me_destination%/*}" ]; then
 		mkdir -p ${_me_destination%/*}
 	fi
@@ -160,11 +163,61 @@ Extract_me(){
 	fi
 
 	printf 'extracting and stripping intel management engine\n'
-	innoextract blobs/me.exe -d blobs || Fail 'could not extract me executable with innoextract' 
+	innoextract blobs/me.exe -d blobs \
-	./me_cleaner/me_cleaner.py -r -t -O ${_me_destination} blobs/app/*ME*.bin \
+		|| 7z x blobs/me.exe -oblobs/app \
-	|| ./resources/blobs/me7_update_parser.py -O ${_me_destination} blobs/app/ME7*.bin \
+		|| Fail 'could not extract me executable with innoextract' 
-	|| return 1
+
+	Bruteforce_extract_me "$(pwd)/${_me_destination}" "$(pwd)/blobs/app" \
+		|| return 1
+
 	printf "Truncated and cleaned me output to ${_me_destination}\n"
+	return 0
+}
+
+# cursed, carcinogenic code. TODO rewrite it better
+Bruteforce_extract_me() {
+       _me_destination="${1}"
+       cdir="${2}" # must be an absolute path, not relative
+
+	if [ -f "${_me_destination}" ]; then
+		return 0
+	fi
+
+       (
+       printf "Entering %s\n" "${cdir}"
+       cd "${cdir}" || exit 1
+       for i in *; do
+               if [ -f "${_me_destination}" ]; then
+                       # me.bin found, so avoid needless further traversal
+                       break
+               elif [ -L "${i}" ]; then
+                       # symlinks are a security risk, in this context
+                       continue
+               elif [ -f "${i}" ]; then
+                       "${mecleaner}" -r -t -O "${_me_destination}" "${i}" \
+                               && break # (we found me.bin)
+			"${me7updateparser}" -O ${_me_destination} "${i}" \
+				&& break
+                       _7ztest="${_7ztest}a"
+                       7z x "${i}" -o${_7ztest} || continue
+                       Bruteforce_extract_me "${_me_destination}" "${cdir}/${_7ztest}"
+                       cdir="${1}"
+                       cd "${cdir}"
+               elif [ -d "$i" ]; then
+                       Bruteforce_extract_me "${_me_destination}" "${cdir}/${i}"
+                       cdir="${1}"
+                       cd "${cdir}"
+               else
+                       printf "SKIPPING: %s\n" "${i}"
+               fi
+       done
+       )
+       if [ ! -f "${_me_destination}" ]; then
+               printf "me.bin not found in vendor update for board: `%s`\n" ${board}
+               return 1
+       else
+               return 0
+       fi
 }
 
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