tools/create-image.sh: add option to specify output prefix

Add an option, -o / --output, to specify a prefix used for the name of the
directory where debootstrap generates the system, and the final disk image
and SSH key filenames.

The default remains using the distro release codename.

For now, ban the use of slashes, spaces, . and .. as output names.

Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>

Author: ajdlinux

tools/create-image.sh

@@ -29,9 +29,12 @@ display_help() {
     echo "   -d, --distribution         Set on which Debian distribution to create (default: $RELEASE)"
     echo "   -f, --feature              Check what packages to install in the image, options are minimal, full (default: $FEATURE)"
     echo "   -h, --help                 Display help message"
+    echo "   -o, --output               Set output prefix (default: value of --distribution)"
     echo "   -p, --add-perf             Add perf support. Requires environment variable \$KERNEL pointing to kernel source tree"
     echo "   -s, --seek                 Image size in MB (default: $(($SEEK + 1)))"
     echo
+    echo "The chroot will be created in ./<output>, the final image will be created in ./<output>.img, and SSH keys will be named"
+    echo "./<output>.id_rsa[.pub]."
 }
 
 while true; do
@@ -56,6 +59,15 @@ while true; do
             FEATURE=$2
             shift 2
             ;;
+        -o | --output)
+            if [[ "$2" == *"/"* || "$2" == *" "* || "$2" == "." || "$2" == ".." ]]
+            then
+                echo "Error: output prefix cannot contain /, spaces, or be . or .."
+                exit 1
+            fi
+            OUTPUT="$2"
+            shift 2
+            ;;
         -p | --add-perf)
             PERF=true
             shift 1
@@ -127,7 +139,7 @@ if [ $FEATURE = "full" ]; then
     PREINSTALL_PKGS=$PREINSTALL_PKGS","$ADD_PACKAGE
 fi
 
-DIR=$RELEASE
+DIR="${OUTPUT:-$RELEASE}"
 sudo rm -rf $DIR
 sudo mkdir -p $DIR
 sudo chmod 0755 $DIR
@@ -174,9 +186,9 @@ echo 'binfmt_misc /proc/sys/fs/binfmt_misc binfmt_misc defaults 0 0' | sudo tee
 echo -en "127.0.0.1\tlocalhost\n" | sudo tee $DIR/etc/hosts
 echo "nameserver 8.8.8.8" | sudo tee -a $DIR/etc/resolv.conf
 echo "syzkaller" | sudo tee $DIR/etc/hostname
-ssh-keygen -f $RELEASE.id_rsa -t rsa -N ''
+ssh-keygen -f $DIR.id_rsa -t rsa -N ''
 sudo mkdir -p $DIR/root/.ssh/
-cat $RELEASE.id_rsa.pub | sudo tee $DIR/root/.ssh/authorized_keys
+cat $DIR.id_rsa.pub | sudo tee $DIR/root/.ssh/authorized_keys
 
 # Add perf support
 if [ $PERF = "true" ]; then
@@ -195,9 +207,9 @@ fi
 echo 'ATTR{name}=="vim2m", SYMLINK+="vim2m"' | sudo tee -a $DIR/etc/udev/rules.d/50-udev-default.rules
 
 # Build a disk image
-dd if=/dev/zero of=$RELEASE.img bs=1M seek=$SEEK count=1
-sudo mkfs.ext4 -F $RELEASE.img
+dd if=/dev/zero of=$DIR.img bs=1M seek=$SEEK count=1
+sudo mkfs.ext4 -F $DIR.img
 sudo mkdir -p /mnt/$DIR
-sudo mount -o loop $RELEASE.img /mnt/$DIR
+sudo mount -o loop $DIR.img /mnt/$DIR
 sudo cp -a $DIR/. /mnt/$DIR/.
 sudo umount /mnt/$DIR