bin/vm: Support -n for dry-run and "-- --flags" forwarding to QEMU

1 files changed, 51 insertions, 18 deletions

diff --git a/bin/vm b/bin/vm
index 52bcce5..7304cb9 100755
--- a/bin/vm
+++ b/bin/vm
@@ -5,7 +5,7 @@ set -eu
 usage() {
 	cat <<-'EOF'
 		Usage:
-		  vm [-G] [-S] [-v] ACTION [OS]
+		  vm [-G] [-n] [-S] [-v] ACTION [OS [-- QEMU_OPTIONS...]]
 		  vm -h
 	EOF
 }
@@ -15,16 +15,18 @@ help() {
 
 
 		Options:
-		  -G            use graphics
-		  -S            don't write to VM image (snapshot on)
-		  -v            verbose mode
-		  -h, --help    show this message
+		  -G              use graphics
+		  -n              dry-run: don't execute any code, assumes -v
+		  -S              don't write to VM image (snapshot on)
+		  -v              verbose mode
+		  -h, --help      show this message
 
-		  ACTION        one of:
-		                - up
-		                - down
-		                - status
-		  OS            the name of the OS to be acted upon
+		  ACTION          one of:
+		                  - up
+		                  - down
+		                  - status
+		  OS              the name of the OS to be acted upon
+		  QEMU_OPTIONS    command line options to be given verbatim to QEMU
 
 
 		Manage the state of known virtual machines.
@@ -78,14 +80,19 @@ for flag in "$@"; do
 	esac
 done
 
+DRY_RUN=false
 GRAPHICS=false
 SNAPSHOT=false
 VERBOSE=false
-while getopts 'GSvh' flag; do
+while getopts 'GnSvh' flag; do
 	case "$flag" in
 		G)
 			GRAPHICS=true
 			;;
+		n)
+			DRY_RUN=true
+			VERBOSE=true
+			;;
 		S)
 			SNAPSHOT=true
 			;;
@@ -150,6 +157,7 @@ ACTION="${1:-}"
 OS="${2:-}"
 
 eval "$(assert-arg "$ACTION" 'ACTION')"
+shift
 
 
 FLAGS=''
@@ -180,6 +188,11 @@ case "$ACTION" in
 		;;
 	up)
 		eval "$(assert-arg "$OS" 'OS')"
+		shift
+		if [ "${1:-}" = '--' ]; then
+			shift
+		fi
+
 		OS="$(guess_name "$OS")"
 		PID_F="$RUNDIR/$OS.pid"
 		PORT_F="$RUNDIR/$OS.port"
@@ -192,16 +205,25 @@ case "$ACTION" in
 
 		PORT="$(free-port)"
 		QCOW="$QCOW_DIR"/"$OS".qcow2
-		if [ "$VERBOSE" = true ]; then
-			set -x
-		fi
+
 		# shellcheck disable=2086
-		qemu-system-x86_64 \
+		set -- qemu-system-x86_64 \
 			-m 1G                                           \
 			-nic user,model=virtio,hostfwd=tcp::"$PORT"-:22 \
 			-drive file="$QCOW",media=disk,if=virtio        \
 			-enable-kvm                                     \
-			$FLAGS 1>>"$LOGS" 2>&1 &
+			$FLAGS "$@"
+
+		if [ "$DRY_RUN" = true ]; then
+			echo "$@"
+			exit
+		fi
+
+		if [ "$VERBOSE" = true ]; then
+			set -x
+		fi
+
+		"$@" 1>>"$LOGS" 2>&1 &
 		PID=$!
 		set +x
 		printf '%s' "$PID"  > "$PID_F"
@@ -211,6 +233,11 @@ case "$ACTION" in
 		;;
 	down)
 		eval "$(assert-arg "$OS" 'OS')"
+		shift
+		if [ "${1:-}" = '--' ]; then
+			shift
+		fi
+
 		OS="$(guess_name "$OS")"
 		PID_F="$RUNDIR/$OS.pid"
 		PORT_F="$RUNDIR/$OS.port"
@@ -221,8 +248,14 @@ case "$ACTION" in
 		fi
 
 		PID="$(cat "$PID_F")"
-		rm -f "$PID_F" "$PORT_F"
-		kill "$PID"
+
+		if [ "$DRY_RUN" = true ]; then
+			echo rm -f "$PID_F" "$PORT_F"
+			echo kill "$PID"
+		else
+			rm -f "$PID_F" "$PORT_F"
+			kill "$PID"
+		fi
 
 		write_ssh_config
 		;;