Add CLI options: --help, --quiet, and --dry-run

patch.sh

@@ -1,7 +1,78 @@
 #!/bin/bash
 set -euo pipefail
 
-BINARY_FILE=$1
+# CLI options
+QUIET=0
+DRY_RUN=0
+BINARY_FILE=""
+
+# Help text
+show_help() {
+    cat << EOF
+Usage: $0 [OPTIONS] <binary_file>
+
+Patches Mattermost Enterprise Edition binary to bypass license validation.
+
+Options:
+  -h, --help     Show this help message and exit
+  -q, --quiet    Suppress non-error output
+  --dry-run      Show what would be patched without making changes
+
+Exit codes:
+  0  Success
+  1  General error
+  2  Missing dependencies
+  3  No binary file specified
+  4  File does not exist
+  5  No write permission
+  6  Already patched
+  7  Pattern not found
+  8  Invalid offset calculated
+  9  Failed to write patch
+  10 Patch verification failed
+  11 Not an ELF binary
+
+EOF
+}
+
+# Parse arguments
+while [[ $# -gt 0 ]]; do
+    case $1 in
+        -h|--help)
+            show_help
+            exit 0
+            ;;
+        -q|--quiet)
+            QUIET=1
+            shift
+            ;;
+        --dry-run)
+            DRY_RUN=1
+            shift
+            ;;
+        -*)
+            echo "Error: Unknown option: $1" >&2
+            echo "Use '$0 --help' for usage information." >&2
+            exit 1
+            ;;
+        *)
+            if [ -z "$BINARY_FILE" ]; then
+                BINARY_FILE="$1"
+            else
+                echo "Error: Multiple binary files specified." >&2
+                exit 1
+            fi
+            shift
+            ;;
+    esac
+done
+
+# Helper for conditional output
+log() {
+    if [ "$QUIET" -eq 0 ]; then
+        echo "$@"
+    fi
+}
 PATTERN="48 89 C1 48 8B 84 24 ?? ?? ?? ?? E8 ?? ?? ?? ?? 48 85 C0 74 53"
 REPLACEMENT="75"
 OFFSET=19
@@ -36,25 +107,25 @@ fi
 
 # Check binary file argument exists and is writable
 if [ -z "$BINARY_FILE" ]; then
-    echo "Error: No binary file specified."
-    echo "Usage: $0 <binary_file>"
+    echo "Error: No binary file specified." >&2
+    show_help >&2
     exit 3
 fi
 
 if [ ! -f "$BINARY_FILE" ]; then
-    echo "Error: File '$BINARY_FILE' does not exist."
+    echo "Error: File '$BINARY_FILE' does not exist." >&2
     exit 4
 fi
 
 if [ ! -w "$BINARY_FILE" ]; then
-    echo "Error: No write permission for '$BINARY_FILE'."
+    echo "Error: No write permission for '$BINARY_FILE'." >&2
     exit 5
 fi
 
 # Check if file is an ELF binary
 FILE_TYPE=$(file -b "$BINARY_FILE" 2>/dev/null || echo "unknown")
 if ! echo "$FILE_TYPE" | grep -q "ELF"; then
-    echo "Error: '$BINARY_FILE' does not appear to be an ELF binary (detected: $FILE_TYPE)."
+    echo "Error: '$BINARY_FILE' does not appear to be an ELF binary (detected: $FILE_TYPE)." >&2
     exit 11
 fi
 
@@ -78,31 +149,31 @@ if [ ! -w "$BINARY_FILE" ]; then
     exit 1
 fi
 
-echo "Dumping hexcode of original binary"
+log "Dumping hexcode of original binary"
 
 TEMP_FILE=$(mktemp)
 hexdump -ve '1/1 "%.2x"' "$BINARY_FILE" > "$TEMP_FILE"
 
-echo "Searching for rsa.VerifyPKCS1v15 call inside LicenseValidatorImpl.ValidateLicense()"
+log "Searching for rsa.VerifyPKCS1v15 call inside LicenseValidatorImpl.ValidateLicense()"
 
 # Check if already patched
 PATCHED_COUNT=$(grep -Eo -b "$PATCHED_PATTERN" "$TEMP_FILE" 2>/dev/null | wc -l)
 if [ "$PATCHED_COUNT" -gt 0 ]; then
-    echo "Binary appears to already be patched (jnz instruction found)."
+    log "Binary appears to already be patched (jnz instruction found)."
     exit 6
 fi
 
 MATCH_COUNT=$(grep -Eo -b "$SEARCH_PATTERN" "$TEMP_FILE" | wc -l)
 if [ "$MATCH_COUNT" -gt 1 ]; then
-    echo "Warning: Found $MATCH_COUNT matches for the pattern. Using the first match."
-    echo "If patching fails or produces unexpected results, please report this at:"
-    echo "  https://github.com/<your-repo>/issues"
+    log "Warning: Found $MATCH_COUNT matches for the pattern. Using the first match."
+    log "If patching fails or produces unexpected results, please report this at:"
+    log "  https://github.com/<your-repo>/issues"
 fi
 
 FOUND_OFFSET=$(grep -Eo -b "$SEARCH_PATTERN" "$TEMP_FILE" | awk -F: '{print $1}' | head -n 1)
 
 if [ -z "$FOUND_OFFSET" ]; then
-  echo "Call not found!"
+  echo "Call not found!" >&2
   exit 7
 fi
 
@@ -110,22 +181,28 @@ BYTE_OFFSET=$((FOUND_OFFSET / 2 + OFFSET))
 BYTE_OFFSET_HEX=$(printf "%x" "$BYTE_OFFSET")
 
 if [ "$BYTE_OFFSET" -lt 0 ]; then
-  echo "Error: Calculated offset is before the start of the file!"
+  echo "Error: Calculated offset is before the start of the file!" >&2
   exit 8
 fi
 
-echo "Call found, patching jz at offset 0x$BYTE_OFFSET_HEX with jnz"
+log "Call found, patching jz at offset 0x$BYTE_OFFSET_HEX with jnz"
+
+if [ "$DRY_RUN" -eq 1 ]; then
+    log "Dry run: Would patch byte at offset 0x$BYTE_OFFSET_HEX from 0x74 to 0x75"
+    log "No changes made to '$BINARY_FILE'."
+    exit 0
+fi
 
 if ! printf "$REPLACEMENT" | xxd -r -p | dd of="$BINARY_FILE" bs=1 seek="$BYTE_OFFSET" conv=notrunc > /dev/null 2>&1; then
-    echo "Error: Failed to write patch to '$BINARY_FILE'."
+    echo "Error: Failed to write patch to '$BINARY_FILE'." >&2
     exit 9
 fi
 
 # Verify the patch was applied
 WRITTEN_BYTE=$(dd if="$BINARY_FILE" bs=1 skip="$BYTE_OFFSET" count=1 2>/dev/null | xxd -p)
 if [ "$WRITTEN_BYTE" != "$REPLACEMENT" ]; then
-    echo "Error: Patch verification failed! Expected '$REPLACEMENT' but found '$WRITTEN_BYTE' at offset 0x$BYTE_OFFSET_HEX."
+    echo "Error: Patch verification failed! Expected '$REPLACEMENT' but found '$WRITTEN_BYTE' at offset 0x$BYTE_OFFSET_HEX." >&2
     exit 10
 fi
 
-echo "Licensing code patched!"
+log "Licensing code patched!"