debvm-run: extract kernel image before inspecting it

Reported-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 11 insertions, 6 deletions

diff --git a/bin/debvm-run b/bin/debvm-run
index 10e19be..0c4ad2e 100755
--- a/bin/debvm-run
+++ b/bin/debvm-run
@@ -104,6 +104,13 @@ die() {
 	echo "$*" 1>&2
 	exit 1
 }
+with_set_ex() {
+	local ret
+	echo "+ $*" 1>&2
+	ret=0
+	"$@" || ret=$?
+	test "$ret" = 0 || die "failed with exit code $ret"
+}
 usage() {
 	die "usage: $0 [-g] [-i image] [-s sshport] [-- qemu options]"
 }
@@ -203,6 +210,9 @@ INITRDNAME=$(/sbin/debugfs "$IMAGE" -R "stat ${BOOTDIR}initrd.img" | sed 's/Fast
 test -n "$INITRDNAME" || die "failed to discover initrd image"
 test "${INITRDNAME#/}" = "$INITRDNAME" && INITRDNAME="$BOOTDIR$INITRDNAME"
 
+with_set_ex /sbin/debugfs "$IMAGE" -R "cat $KERNELNAME" > "$KERNELTMP"
+with_set_ex /sbin/debugfs "$IMAGE" -R "cat $INITRDNAME" > "$INITRDTMP"
+
 # Refine our VMARCH guess from /bin/true using the kernel image to improve
 # experience for multiarch kernels.
 if command -v file >/dev/null 2>&1; then
@@ -342,9 +352,4 @@ set -- \
 	-device "$NIC_DEV" \
 	"$@"
 
-set -ex
-
-/sbin/debugfs "$IMAGE" -R "cat $KERNELNAME" > "$KERNELTMP"
-/sbin/debugfs "$IMAGE" -R "cat $INITRDNAME" > "$INITRDTMP"
-
-"$QEMU" "$@"
+with_set_ex "$QEMU" "$@"