tools/create-gce-image.sh: support both nbd and loop

Pass target OS/arch and VM type to kernel.CreateImage.
Use nbd for gce and loop for qemu VM type.

2 files changed, 39 insertions, 12 deletions

diff --git a/pkg/kernel/generated.go b/pkg/kernel/generated.go
index a20e4aea8..9c8fe51e8 100644
--- a/pkg/kernel/generated.go
+++ b/pkg/kernel/generated.go
@@ -7,8 +7,6 @@ const createImageScript = `#!/bin/bash
 
 set -eux
 
-trap "" SIGINT
-
 CLEANUP=""
 trap 'eval " $CLEANUP"' EXIT
 
@@ -22,20 +20,41 @@ if [ "$(basename $2)" != "bzImage" ]; then
 	exit 1
 fi
 
+SYZ_VM_TYPE="${SYZ_VM_TYPE:-qemu}"
+if [ "$SYZ_VM_TYPE" == "qemu" ]; then
+	:
+elif [ "$SYZ_VM_TYPE" == "gce" ]; then
+	:
+else
+	echo "SYZ_VM_TYPE has unsupported value $SYZ_VM_TYPE"
+	exit 1
+fi
+
 sudo umount disk.mnt || true
-sudo qemu-nbd -d /dev/nbd0 || true
+if [ "$SYZ_VM_TYPE" == "qemu" ]; then
+	:
+elif [ "$SYZ_VM_TYPE" == "gce" ]; then
+	sudo modprobe nbd
+	sudo qemu-nbd -d /dev/nbd0 || true
+fi
 rm -rf disk.mnt disk.raw || true
 
-sudo modprobe nbd
 fallocate -l 2G disk.raw
-sudo qemu-nbd -c /dev/nbd0 --format=raw disk.raw
-CLEANUP="sudo qemu-nbd -d /dev/nbd0; $CLEANUP"
-echo -en "o\nn\np\n1\n\n\na\nw\n" | sudo fdisk /dev/nbd0
-until [ -e /dev/nbd0p1 ]; do sleep 1; done
-sudo -E mkfs.ext4 /dev/nbd0p1
+if [ "$SYZ_VM_TYPE" == "qemu" ]; then
+	DISKDEV="$(sudo losetup -f --show -P disk.raw)"
+	CLEANUP="sudo losetup -d $DISKDEV; $CLEANUP"
+elif [ "$SYZ_VM_TYPE" == "gce" ]; then
+	DISKDEV="/dev/nbd0"
+	sudo qemu-nbd -c $DISKDEV --format=raw disk.raw
+	CLEANUP="sudo qemu-nbd -d $DISKDEV; $CLEANUP"
+fi
+echo -en "o\nn\np\n1\n\n\na\nw\n" | sudo fdisk $DISKDEV
+PARTDEV=$DISKDEV"p1"
+until [ -e $PARTDEV ]; do sleep 1; done
+sudo -E mkfs.ext4 $PARTDEV
 mkdir -p disk.mnt
 CLEANUP="rm -rf disk.mnt; $CLEANUP"
-sudo mount /dev/nbd0p1 disk.mnt
+sudo mount $PARTDEV disk.mnt
 CLEANUP="sudo umount disk.mnt; $CLEANUP"
 sudo cp -a $1/. disk.mnt/.
 sudo cp $2 disk.mnt/vmlinuz
@@ -90,5 +109,5 @@ menuentry 'linux' --class gnu-linux --class gnu --class os {
 	linux /vmlinuz root=/dev/sda1 console=ttyS0 earlyprintk=serial vsyscall=native rodata=n ftrace_dump_on_oops=orig_cpu oops=panic panic_on_warn=1 nmi_watchdog=panic panic=86400 $CMDLINE
 }
 EOF
-sudo grub-install --target=i386-pc --boot-directory=disk.mnt/boot --no-floppy /dev/nbd0
+sudo grub-install --target=i386-pc --boot-directory=disk.mnt/boot --no-floppy $DISKDEV
 `
diff --git a/pkg/kernel/kernel.go b/pkg/kernel/kernel.go
index fce4c1b1f..21612f10a 100644
--- a/pkg/kernel/kernel.go
+++ b/pkg/kernel/kernel.go
@@ -70,7 +70,14 @@ func Clean(dir string) error {
 // If cmdlineFile is not empty, contents of the file are appended to the kernel command line.
 // If sysctlFile is not empty, contents of the file are appended to the image /etc/sysctl.conf.
 // Produces image and root ssh key in the specified files.
-func CreateImage(kernelDir, userspaceDir, cmdlineFile, sysctlFile, image, sshkey string) error {
+func CreateImage(targetOS, targetArch, vmType, kernelDir, userspaceDir, cmdlineFile, sysctlFile,
+	image, sshkey string) error {
+	if targetOS != "linux" || targetArch != "amd64" {
+		return fmt.Errorf("only linux/amd64 is supported")
+	}
+	if vmType != "qemu" && vmType != "gce" {
+		return fmt.Errorf("images can be built only for qemu/gce machines")
+	}
 	tempDir, err := ioutil.TempDir("", "syz-build")
 	if err != nil {
 		return err
@@ -85,6 +92,7 @@ func CreateImage(kernelDir, userspaceDir, cmdlineFile, sysctlFile, image, sshkey
 	cmd.Dir = tempDir
 	cmd.Env = append([]string{}, os.Environ()...)
 	cmd.Env = append(cmd.Env,
+		"SYZ_VM_TYPE="+vmType,
 		"SYZ_CMDLINE_FILE="+osutil.Abs(cmdlineFile),
 		"SYZ_SYSCTL_FILE="+osutil.Abs(sysctlFile),
 	)