From ef37aa6d6448f66114c741cac0dd8da54967bf7b Mon Sep 17 00:00:00 2001
From: Ian Skinner <56081713+IanSkinner1982@users.noreply.github.com>
Date: Sun, 20 Aug 2023 20:55:48 -0400
Subject: [PATCH]

---
 extract-updater-rofs.sh | 53 ++++++++++++++++++++++-------------------
 1 file changed, 28 insertions(+), 25 deletions(-)

diff --git a/extract-updater-rofs.sh b/extract-updater-rofs.sh
index e794186..124a62a 100644
--- a/extract-updater-rofs.sh
+++ b/extract-updater-rofs.sh
@@ -1,6 +1,6 @@
 #   extract-updater-rofs
 # Extracts firmware CIAs from ROFS containers for some gigaleak SystemUpdaters.
-# Place in same directory as ROFS named "romfs.bin"
+# Place in same directory as an extracted "romfs.bin" OR "Contents.cnt"
 
 echo "Finding CIA headers in file..."
 od -t x -A d romfs.bin | grep "00002020 00000000 00000a00 00000350" | sed 's/ .*//' | sed 's/^0*//' > romfs-dir.txt
@@ -76,27 +76,30 @@ START_HEADER=$( tail -n 1 romfs-dir.txt )
 NEXT_HEADER=$((16#$(xxd romfs.bin | grep "226e 6f6e 6522" | sed 's/: .*//' | sed 's/^0*//')));
 # Find "226e 6f6e 6522" as it is the last predictable data to mark the end of Contents.cnt and the last CIA.
 # Upsettingly I have to use xxd because od wouldn't turn up any results for this... I liked od's formatting more :despair:
-echo "    Check CIA length"
-echo "Final CIA header at          ${START_HEADER}"
-echo "Contents.cnt end at         ${NEXT_HEADER}"
-echo "Finding end of final CIA from Contents.cnt end..."
-y="00"
-x=16
-# Start x as 16 to skip changing data and go right to padding
-while [ "$y" = "00" ]; do
-    x+=1
-    y=$(od -j $((NEXT_HEADER - x)) -N 1 -x -A n romfs.bin | sed 's|[ ,]||g' | sed 's/^..//');
-    # Get bytes one backwards from next header
-    # printf '%x\n' $((NEXT_HEADER - x))
-    # echo $y
-    # echo $x
-done
-echo "End found!"
-echo "Non-zerobyte ($y) at $((NEXT_HEADER - x))"
-echo "Padding from final CIA to Content.cnt end is $((x - 1)) bytes."
-echo "    Extract CIA"
-CIA_LENGTH=$(((NEXT_HEADER - START_HEADER) - x + 1))
-dd skip=${START_HEADER} count=${CIA_LENGTH} if=romfs.bin of="0.cia" bs=1
-echo "Final CIA output as '0.cia', ${CIA_LENGTH} bytes."
-echo "================================================="
-echo "All CIAs extracted from RomFS!"
\ No newline at end of file
+if [ $NEXT_HEADER != "" ]; then
+    echo "    Check CIA length"
+    echo "Final CIA header at          ${START_HEADER}"
+    echo "Contents.cnt end at         ${NEXT_HEADER}"
+    echo "Finding end of final CIA from Contents.cnt end..."
+    y="00"
+    x=16
+    # Start x as 16 to skip changing data and go right to padding
+    while [ "$y" = "00" ]; do
+        x+=1
+        y=$(od -j $((NEXT_HEADER - x)) -N 1 -x -A n romfs.bin | sed 's|[ ,]||g' | sed 's/^..//');
+        # Get bytes one backwards from next header
+        # printf '%x\n' $((NEXT_HEADER - x))
+        # echo $y
+        # echo $x
+    done
+    echo "End found!"
+    echo "Non-zerobyte ($y) at $((NEXT_HEADER - x))"
+    echo "Padding from final CIA to Content.cnt end is $((x - 1)) bytes."
+    echo "    Extract CIA"
+    CIA_LENGTH=$(((NEXT_HEADER - START_HEADER) - x + 1))
+    dd skip=${START_HEADER} count=${CIA_LENGTH} if=romfs.bin of="0.cia" bs=1
+    echo "Final CIA output as '0.cia', ${CIA_LENGTH} bytes."
+    echo "================================================="
+    echo "All CIAs extracted from RomFS!"
+else
+    echo "Could not find end of last CIA! For extracting manually, start address is ${START_HEADER} (decimal)"
\ No newline at end of file