Merge run-skip into main

1 files changed, 80 insertions, 14 deletions

diff --git a/bin/debvm-run b/bin/debvm-run
index 1019ac7..bba0c15 100755
--- a/bin/debvm-run
+++ b/bin/debvm-run
@@ -49,6 +49,40 @@ Using this option, you can customize the value of that B<-netdev> option.
 For instance, you can set up additional port forwards by passing e.g. C<--netopt hostfwd=:127.0.0.1:8080-:80>.
 It can be used multiple times.
 
+=item B<--skip>=I<task>
+
+Skip a particular task or feature.
+The option may be specified multiple times or list multiple tasks to be skipped by separating them with a comma.
+By default, no tasks are skipped.
+The following tasks may be skipped.
+
+=over 4
+
+=item B<network>
+
+Do not pass configure network card.
+
+=item B<rngdev>
+
+Do not pass a random number generator device.
+
+=item B<root>
+
+Skip all of the following tasks matching C<root/*>.
+If either of these is present, the VM will not boot unless a suitable replacement is added in another way.
+
+=item B<root/cmd>
+
+Since B<debvm-run> uses B<qemu> as bootloader it normally passes the label of the root block device via the kernel command line.
+This passing can be inhibited to supply a different location.
+
+=item B<root/dev>
+
+A block device for the root filesystem is no longer passed.
+This can be used to customize the block device.
+
+=back
+
 =item B<-s> I<sshport>, B<--sshport>=I<sshport>
 
 If given, B<qemu> is configured to pass connections to I<127.0.0.1:sshport> to port 22 of the virtual machine.
@@ -113,6 +147,7 @@ IMAGE=rootfs.ext4
 GRAPHICAL=
 CMDLINE_APPEND=
 NETOPTS=
+SKIP=,
 SSHPORT=
 
 nth_arg() {
@@ -152,6 +187,9 @@ opt_image() {
 opt_netopt() {
 	NETOPTS="$NETOPTS,$1"
 }
+opt_skip() {
+	SKIP="$SKIP$1,"
+}
 opt_sshport() {
 	SSHPORT=$1
 }
@@ -169,12 +207,12 @@ while getopts :gi:s:-: OPTCHAR; do
 				graphical)
 					"opt_$OPTARG"
 				;;
-				append|image|netopt|sshport)
+				append|image|netopt|skip|sshport)
 					test "$OPTIND" -gt "$#" && usage_error "missing argument for --$OPTARG"
 					"opt_$OPTARG" "$(nth_arg "$OPTIND" "$@")"
 					OPTIND=$((OPTIND+1))
 				;;
-				append=*|image=*|netopt=*|sshport=*)
+				append=*|image=*|netopt=*|skip=*|sshport=*)
 					"opt_${OPTARG%%=*}" "${OPTARG#*=}"
 				;;
 				*)
@@ -206,6 +244,18 @@ if ! printf '\123\357' | cmp --bytes=2 "$IMAGE" - 1080; then
 	die "image '$IMAGE' is not in ext4 format"
 fi
 
+check_skip() {
+	while :; do
+		case "$SKIP" in
+			*",$1,"*)	return 0 ;;
+		esac
+		if test "$1" = "${1%/*}"; then
+			return 1
+		fi
+		set -- "${1%/*}"
+	done
+}
+
 cleanup() {
 	set +x
 	test -n "$KERNELTMP" && rm -f "$KERNELTMP"
@@ -271,7 +321,10 @@ case "$IMAGE_LABEL" in
 	;;
 esac
 
-KERNEL_CMDLINE="root=LABEL=$IMAGE_LABEL rw"
+KERNEL_CMDLINE=
+if ! check_skip root/cmd; then
+	KERNEL_CMDLINE="root=LABEL=$IMAGE_LABEL rw"
+fi
 
 KERNELFD=3
 while test -h "/proc/self/fd/$KERNELFD"; do
@@ -293,10 +346,14 @@ set -- \
 	-m 1G \
 	-kernel "/proc/self/fd/$KERNELFD" \
 	-initrd "/proc/self/fd/$INITRDFD" \
-	-drive "media=disk,format=raw,discard=unmap,file=$IMAGE,if=virtio,cache=unsafe" \
-	-object rng-random,filename=/dev/urandom,id=rng0 \
 	"$@"
 
+if ! check_skip root/dev; then
+	set -- \
+		-drive "media=disk,format=raw,discard=unmap,file=$IMAGE,if=virtio,cache=unsafe" \
+		"$@"
+fi
+
 # Translate KERNELARCH (a Debian architecture) to a Debian CPU name.
 # This utilizes the QEMU Debian package symlink mapping that ensures that
 # calling qemu-system-${DEB_HOST_ARCH_CPU} will run the QEMU binary providing
@@ -385,19 +442,22 @@ if test -z "$MAX_SMP" || test "$MAX_SMP" -gt 1; then
 		set -- -smp "$NPROC" "$@"
 	fi
 fi
-if test -n "$RNG_DEV"; then
-	set -- -device "$RNG_DEV" "$@"
+if test -n "$RNG_DEV" && ! check_skip rngdev; then
+	set -- \
+		-device "$RNG_DEV" \
+		-object rng-random,filename=/dev/urandom,id=rng0 \
+		"$@"
 fi
 
 if test -z "$GRAPHICAL"; then
 	set -- -nographic "$@"
 	case "$KERNELARCH" in
 		amd64|i386)
-			KERNEL_CMDLINE="$KERNEL_CMDLINE console=ttyS0"
+			KERNEL_CMDLINE="${KERNEL_CMDLINE:+"$KERNEL_CMDLINE "}console=ttyS0"
 		;;
 	esac
 	if test -t 0 && test -t 1 && test -n "$TERM"; then
-		KERNEL_CMDLINE="$KERNEL_CMDLINE TERM=$TERM"
+		KERNEL_CMDLINE="${KERNEL_CMDLINE:+"$KERNEL_CMDLINE "}TERM=$TERM"
 	fi
 else
 	case "$KERNELARCH" in
@@ -421,11 +481,17 @@ DNSSEARCH=$(dnsdomainname)
 if test -n "$DNSSEARCH"; then
 	NETOPTS=",domainname=$DNSSEARCH$NETOPTS"
 fi
-set -- \
-	-append "$KERNEL_CMDLINE${CMDLINE_APPEND:+ $CMDLINE_APPEND}" \
-	-netdev "user,id=net0$NETOPTS" \
-	-device "$NIC_DEV" \
-	"$@"
+
+if test -n "$CMDLINE_APPEND"; then
+	KERNEL_CMDLINE="${KERNEL_CMDLINE:+"$KERNEL_CMDLINE "}$CMDLINE_APPEND"
+fi
+if test -n "$KERNEL_CMDLINE"; then
+	set -- -append "$KERNEL_CMDLINE" "$@"
+fi
+
+if ! check_skip network; then
+	set -- -netdev "user,id=net0$NETOPTS" -device "$NIC_DEV" "$@"
+fi
 
 echo "+ $QEMU $*" 1>&2
 exec "$QEMU" "$@"