Fix variable quoting to prevent word splitting

This properly quotes all variable expansions and uses bash arrays for
file lists to prevent word splitting issues:
- Use mapfile to populate SOURCES array instead of command substitution
- Quote all command substitutions and variable assignments
- Use "${SOURCES[@]}" for proper array expansion
- Quote exit codes and function parameters

Author: jserv

.ci/check-format.sh

@@ -2,8 +2,9 @@
 
 set -euo pipefail
 
-SOURCES=$(git ls-files '*.c' '*.cxx' '*.cpp' '*.h' '*.hpp')
+# Get list of source files into array
+mapfile -t SOURCES < <(git ls-files '*.c' '*.cxx' '*.cpp' '*.h' '*.hpp')
 
 # Use clang-format dry-run mode with --Werror to fail on format violations
 # This eliminates the need for temporary files and manual diff comparisons
-clang-format-18 -n --Werror ${SOURCES}
+clang-format-18 -n --Werror "${SOURCES[@]}"

.ci/common.sh

@@ -4,8 +4,8 @@
 set -euo pipefail
 
 # Detect platform
-MACHINE_TYPE=$(uname -m)
-OS_TYPE=$(uname -s)
+MACHINE_TYPE="$(uname -m)"
+OS_TYPE="$(uname -s)"
 
 # Cleanup function - kills all semu processes
 cleanup() {
@@ -22,14 +22,14 @@ ASSERT() {
     local exit_code
 
     set +e
-    cmd_output=$("$@" 2>&1)
+    cmd_output="$("$@" 2>&1)"
     exit_code=$?
     set -e
 
-    if [ $exit_code -ne 0 ]; then
+    if [ "$exit_code" -ne 0 ]; then
         echo "Assert failed: $*" >&2
         echo "Output: $cmd_output" >&2
-        exit $exit_code
+        exit "$exit_code"
     fi
 }
 
@@ -59,7 +59,7 @@ get_timeout() {
 }
 
 # Export TIMEOUT for use in scripts
-TIMEOUT=$(get_timeout)
+TIMEOUT="$(get_timeout)"
 export TIMEOUT
 
 # Color codes for output

.ci/test-netdev.sh

@@ -20,7 +20,7 @@ esac
 
 # Test network device functionality
 TEST_NETDEV() {
-    local NETDEV=$1
+    local NETDEV="$1"
     local CMD_PREFIX=""
 
     if [ "$NETDEV" == "tap" ]; then

.github/workflows/main.yml

@@ -111,20 +111,20 @@ jobs:
       run: |
         set -euo pipefail
 
-        # Get list of source files
-        SOURCES=$(git ls-files '*.c' '*.cxx' '*.cpp' '*.h' '*.hpp')
+        # Get list of source files into array
+        mapfile -t SOURCES < <(git ls-files '*.c' '*.cxx' '*.cpp' '*.h' '*.hpp')
 
         # Register cleanup function to restore files on exit
         cleanup_files() {
-          if [ -n "${SOURCES:-}" ]; then
+          if [ ${#SOURCES[@]} -gt 0 ]; then
             echo "Restoring files to original state..."
-            git checkout -- ${SOURCES} 2>/dev/null || true
+            git checkout -- "${SOURCES[@]}" 2>/dev/null || true
           fi
         }
         trap cleanup_files EXIT INT TERM
 
         # Apply clang-format in-place to generate diff
-        clang-format-18 -i ${SOURCES}
+        clang-format-18 -i "${SOURCES[@]}"
 
         # Generate diff and pipe to reviewdog
         # Note: reviewdog exit code doesn't affect cleanup due to trap