vcontainer: add auto-start daemon with idle timeout

Add automatic daemon startup and idle timeout cleanup for vdkr/vpdmn:

- vmemres daemon auto-starts on first command (no manual start needed)
- Daemon auto-stops after idle timeout (default: 30 minutes)
- --no-daemon flag for ephemeral mode (single-shot QEMU)
- New config keys: idle-timeout, auto-daemon

Changes:
- vcontainer-init-common.sh: Parse idle_timeout from cmdline, add
  read -t timeout to daemon loop for auto-shutdown
- vrunner.sh: Add --idle-timeout option, pass to kernel cmdline
- vcontainer-common.sh: Auto-start logic in run_runtime_command(),
  --no-daemon flag, config defaults
- container-cross-install.bbclass: Add --no-daemon for explicit
  ephemeral mode during Yocto builds

Configuration:
  vdkr vconfig idle-timeout 3600    # 1 hour timeout
  vdkr vconfig auto-daemon false    # Disable auto-start

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

3 files changed, 100 insertions, 15 deletions

diff --git a/recipes-containers/vcontainer/files/vcontainer-common.sh b/recipes-containers/vcontainer/files/vcontainer-common.sh
index c63d2b3c..7fd62514 100755
--- a/recipes-containers/vcontainer/files/vcontainer-common.sh
+++ b/recipes-containers/vcontainer/files/vcontainer-common.sh
@@ -36,7 +36,7 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 #   3. Default: ~/.config/${VCONTAINER_RUNTIME_NAME}
 #
 # Config file format: key=value (one per line)
-# Supported keys: arch, timeout, state-dir, verbose
+# Supported keys: arch, timeout, state-dir, verbose, idle-timeout, auto-daemon
 # ============================================================================
 
 # Pre-parse --config-dir from command line (needs to happen before detect_default_arch)
@@ -128,11 +128,13 @@ config_list() {
 config_default() {
     local key="$1"
     case "$key" in
-        arch)      uname -m ;;
-        timeout)   echo "300" ;;
-        state-dir) echo "$HOME/.$VCONTAINER_RUNTIME_NAME" ;;
-        verbose)   echo "false" ;;
-        *)         echo "" ;;
+        arch)         uname -m ;;
+        timeout)      echo "300" ;;
+        state-dir)    echo "$HOME/.$VCONTAINER_RUNTIME_NAME" ;;
+        verbose)      echo "false" ;;
+        idle-timeout) echo "1800" ;;   # 30 minutes
+        auto-daemon)  echo "true" ;;   # Auto-start daemon by default
+        *)            echo "" ;;
     esac
 }
 
@@ -387,9 +389,12 @@ ${BOLD}CONFIGURATION (vconfig):${NC}
     ${CYAN}vconfig${NC} <key> <value>        Set configuration value
     ${CYAN}vconfig${NC} <key> --reset        Reset to default value
 
-    Supported keys: arch, timeout, state-dir, verbose
+    Supported keys: arch, timeout, state-dir, verbose, idle-timeout, auto-daemon
     Config file: \$CONFIG_DIR/config (default: ~/.config/${VCONTAINER_RUNTIME_NAME}/config)
 
+    idle-timeout: Daemon idle timeout in seconds [default: 1800]
+    auto-daemon:  Auto-start daemon on first command [default: true]
+
 ${BOLD}GLOBAL OPTIONS:${NC}
     --arch, -a <arch>     Target architecture: x86_64 or aarch64 [default: ${DEFAULT_ARCH}]
     --config-dir <path>   Configuration directory [default: ~/.config/${VCONTAINER_RUNTIME_NAME}]
@@ -400,6 +405,7 @@ ${BOLD}GLOBAL OPTIONS:${NC}
     --storage <file>      Export ${VCONTAINER_RUNTIME_CMD} storage after command (tar file)
     --input-storage <tar> Load ${RUNTIME_UPPER} state from tar before command
     --no-kvm              Disable KVM acceleration (use TCG emulation)
+    --no-daemon           Run in ephemeral mode (don't auto-start/use daemon)
     --verbose, -v         Enable verbose output
     --help, -h            Show this help
 
@@ -529,6 +535,7 @@ NETWORK="true"
 INTERACTIVE="false"
 PORT_FORWARDS=()
 DISABLE_KVM="false"
+NO_DAEMON="false"
 COMMAND=""
 COMMAND_ARGS=()
 
@@ -585,6 +592,10 @@ while [ $# -gt 0 ]; do
             DISABLE_KVM="true"
             shift
             ;;
+        --no-daemon)
+            NO_DAEMON="true"
+            shift
+            ;;
         -it|--interactive)
             INTERACTIVE="true"
             shift
@@ -682,13 +693,37 @@ run_runtime_command() {
     local runtime_cmd="$1"
     local runner_args=$(build_runner_args)
 
+    # Check for --no-daemon flag - use ephemeral mode
+    if [ "$NO_DAEMON" = "true" ]; then
+        [ "$VERBOSE" = "true" ] && echo -e "${CYAN}[$VCONTAINER_RUNTIME_NAME]${NC} Using ephemeral mode (--no-daemon)" >&2
+        "$RUNNER" $runner_args -- "$runtime_cmd"
+        return $?
+    fi
+
     if daemon_is_running; then
         # Use daemon mode - faster
         [ "$VERBOSE" = "true" ] && echo -e "${CYAN}[$VCONTAINER_RUNTIME_NAME]${NC} Using daemon mode" >&2
         "$RUNNER" $runner_args --daemon-send "$runtime_cmd"
     else
-        # Regular mode - start QEMU for this command
-        "$RUNNER" $runner_args -- "$runtime_cmd"
+        # Check if auto-daemon is enabled
+        local auto_daemon=$(config_get "auto-daemon" "true")
+        if [ "$auto_daemon" = "true" ]; then
+            # Auto-start daemon
+            echo -e "${CYAN}[$VCONTAINER_RUNTIME_NAME]${NC} Starting daemon..." >&2
+            local idle_timeout=$(config_get "idle-timeout" "1800")
+            "$RUNNER" $runner_args --idle-timeout "$idle_timeout" --daemon-start
+
+            if daemon_is_running; then
+                [ "$VERBOSE" = "true" ] && echo -e "${CYAN}[$VCONTAINER_RUNTIME_NAME]${NC} Using daemon mode" >&2
+                "$RUNNER" $runner_args --daemon-send "$runtime_cmd"
+            else
+                echo -e "${RED}[$VCONTAINER_RUNTIME_NAME]${NC} Failed to start daemon, using ephemeral mode" >&2
+                "$RUNNER" $runner_args -- "$runtime_cmd"
+            fi
+        else
+            # Auto-daemon disabled - use ephemeral mode
+            "$RUNNER" $runner_args -- "$runtime_cmd"
+        fi
     fi
 }
 
@@ -700,13 +735,37 @@ run_runtime_command_with_input() {
     local runtime_cmd="$3"
     local runner_args=$(build_runner_args)
 
+    # Check for --no-daemon flag - use ephemeral mode
+    if [ "$NO_DAEMON" = "true" ]; then
+        [ "$VERBOSE" = "true" ] && echo -e "${CYAN}[$VCONTAINER_RUNTIME_NAME]${NC} Using ephemeral mode (--no-daemon)" >&2
+        "$RUNNER" $runner_args --input "$input_path" --input-type "$input_type" -- "$runtime_cmd"
+        return $?
+    fi
+
     if daemon_is_running; then
         # Use daemon mode with virtio-9p shared directory
         [ "$VERBOSE" = "true" ] && echo -e "${CYAN}[$VCONTAINER_RUNTIME_NAME]${NC} Using daemon mode for file I/O" >&2
         "$RUNNER" $runner_args --input "$input_path" --input-type "$input_type" --daemon-send-input -- "$runtime_cmd"
     else
-        # Regular mode - start QEMU for this command
-        "$RUNNER" $runner_args --input "$input_path" --input-type "$input_type" -- "$runtime_cmd"
+        # Check if auto-daemon is enabled
+        local auto_daemon=$(config_get "auto-daemon" "true")
+        if [ "$auto_daemon" = "true" ]; then
+            # Auto-start daemon
+            echo -e "${CYAN}[$VCONTAINER_RUNTIME_NAME]${NC} Starting daemon..." >&2
+            local idle_timeout=$(config_get "idle-timeout" "1800")
+            "$RUNNER" $runner_args --idle-timeout "$idle_timeout" --daemon-start
+
+            if daemon_is_running; then
+                [ "$VERBOSE" = "true" ] && echo -e "${CYAN}[$VCONTAINER_RUNTIME_NAME]${NC} Using daemon mode for file I/O" >&2
+                "$RUNNER" $runner_args --input "$input_path" --input-type "$input_type" --daemon-send-input -- "$runtime_cmd"
+            else
+                echo -e "${RED}[$VCONTAINER_RUNTIME_NAME]${NC} Failed to start daemon, using ephemeral mode" >&2
+                "$RUNNER" $runner_args --input "$input_path" --input-type "$input_type" -- "$runtime_cmd"
+            fi
+        else
+            # Auto-daemon disabled - use ephemeral mode
+            "$RUNNER" $runner_args --input "$input_path" --input-type "$input_type" -- "$runtime_cmd"
+        fi
     fi
 }
 
diff --git a/recipes-containers/vcontainer/files/vcontainer-init-common.sh b/recipes-containers/vcontainer/files/vcontainer-init-common.sh
index 872508db..5bfee9b7 100755
--- a/recipes-containers/vcontainer/files/vcontainer-init-common.sh
+++ b/recipes-containers/vcontainer/files/vcontainer-init-common.sh
@@ -106,6 +106,7 @@ parse_cmdline() {
     RUNTIME_NETWORK="0"
     RUNTIME_INTERACTIVE="0"
     RUNTIME_DAEMON="0"
+    RUNTIME_IDLE_TIMEOUT="1800"  # Default: 30 minutes
 
     for param in $(cat /proc/cmdline); do
         case "$param" in
@@ -130,6 +131,9 @@ parse_cmdline() {
             ${VCONTAINER_RUNTIME_PREFIX}_daemon=*)
                 RUNTIME_DAEMON="${param#${VCONTAINER_RUNTIME_PREFIX}_daemon=}"
                 ;;
+            ${VCONTAINER_RUNTIME_PREFIX}_idle_timeout=*)
+                RUNTIME_IDLE_TIMEOUT="${param#${VCONTAINER_RUNTIME_PREFIX}_idle_timeout=}"
+                ;;
         esac
     done
 
@@ -284,6 +288,7 @@ DNSEOF
 
 run_daemon_mode() {
     log "=== Daemon Mode ==="
+    log "Idle timeout: ${RUNTIME_IDLE_TIMEOUT}s"
 
     # Find the virtio-serial port for command channel
     DAEMON_PORT=""
@@ -321,10 +326,10 @@ run_daemon_mode() {
 
     log "Daemon ready, waiting for commands..."
 
-    # Command loop
+    # Command loop with idle timeout
     while true; do
         CMD_B64=""
-        if read -r CMD_B64 <&3; then
+        if read -t "$RUNTIME_IDLE_TIMEOUT" -r CMD_B64 <&3; then
             log "Received: '$CMD_B64'"
             # Handle special commands
             case "$CMD_B64" in
@@ -414,7 +419,15 @@ run_daemon_mode() {
 
             log "Command completed (exit code: $EXEC_EXIT_CODE)"
         else
-            sleep 1
+            # Read returned non-zero: either timeout or error
+            if [ -z "$CMD_B64" ]; then
+                # Timeout expired with no data - shut down
+                log "Idle timeout (${RUNTIME_IDLE_TIMEOUT}s), shutting down..."
+                echo "===IDLE_SHUTDOWN===" | cat >&3
+                break
+            fi
+            # Empty line or other issue - just continue
+            sleep 0.1
         fi
     done
 
diff --git a/recipes-containers/vcontainer/files/vrunner.sh b/recipes-containers/vcontainer/files/vrunner.sh
index 2be33765..cd504f7b 100755
--- a/recipes-containers/vcontainer/files/vrunner.sh
+++ b/recipes-containers/vcontainer/files/vrunner.sh
@@ -122,7 +122,9 @@ OPTIONS:
     --network, -n        Enable networking (slirp user-mode, outbound only)
     --interactive, -it   Run in interactive mode (connects terminal to container)
     --timeout <secs>     QEMU timeout [default: 300]
+    --idle-timeout <s>   Daemon idle timeout in seconds [default: 1800]
     --no-kvm             Disable KVM acceleration (use TCG emulation)
+    --no-daemon          Placeholder for CLI wrapper (ignored by vrunner)
     --batch-import       Batch import mode: import multiple OCI containers in one session
     --keep-temp          Keep temporary files for debugging
     --verbose, -v        Enable verbose output
@@ -195,6 +197,7 @@ BATCH_IMPORT="false"
 # Daemon mode options
 DAEMON_MODE=""          # start, send, stop, status
 DAEMON_SOCKET_DIR=""    # Directory for daemon socket/PID files
+IDLE_TIMEOUT="1800"     # Default: 30 minutes
 
 while [ $# -gt 0 ]; do
     case $1 in
@@ -293,6 +296,15 @@ while [ $# -gt 0 ]; do
             DAEMON_SOCKET_DIR="$2"
             shift 2
             ;;
+        --idle-timeout)
+            IDLE_TIMEOUT="$2"
+            shift 2
+            ;;
+        --no-daemon)
+            # Placeholder for CLI wrapper - vrunner.sh itself doesn't use this
+            # but we accept it so callers can pass it through
+            shift
+            ;;
         --verbose|-v)
             VERBOSE="true"
             shift
@@ -1061,8 +1073,9 @@ if [ "$DAEMON_MODE" = "start" ]; then
     QEMU_OPTS="$QEMU_OPTS -device virtio-serial-pci"
     QEMU_OPTS="$QEMU_OPTS -device virtserialport,chardev=vdkr,name=vdkr"
 
-    # Tell init script to run in daemon mode
+    # Tell init script to run in daemon mode with idle timeout
     KERNEL_APPEND="$KERNEL_APPEND ${CMDLINE_PREFIX}_daemon=1"
+    KERNEL_APPEND="$KERNEL_APPEND ${CMDLINE_PREFIX}_idle_timeout=$IDLE_TIMEOUT"
 
     # Always enable networking for daemon mode
     if [ "$NETWORK" != "true" ]; then