kernelCTF: add local runner

kernelctf/simulator/.gitignore

@@ -0,0 +1,5 @@
+releases/
+ramdisk*.img
+rootfs*.img
+qemu*.sh
+flag

kernelctf/simulator/local_runner.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+set -e
+
+usage() {
+    echo "Usage: $0 <release-name> [--root]";
+    exit 1;
+}
+
+INIT_FN="/home/user/run.sh"
+
+ARGS=()
+while [[ $# -gt 0 ]]; do
+  case $1 in
+    --root) INIT_FN="/bin/bash"; shift;;
+    -*|--*) echo "Unknown option $1"; exit 1;;
+    *) ARGS+=("$1"); shift;;
+  esac
+done
+set -- "${ARGS[@]}"
+
+RELEASE_NAME="$1"
+if [ -z "$RELEASE_NAME" ]; then usage; fi
+
+if [ ! -f "qemu_v2.sh" ]; then wget https://storage.googleapis.com/kernelctf-build/files/qemu_v2.sh; fi
+chmod u+x qemu_v2.sh
+
+if [ ! -d "releases/$RELEASE_NAME" ]; then mkdir -p "releases/$RELEASE_NAME"; fi
+if [ ! -f "releases/$RELEASE_NAME/bzImage" ]; then
+    wget -O "releases/$RELEASE_NAME/bzImage" "https://storage.googleapis.com/kernelctf-build/releases/$RELEASE_NAME/bzImage"
+fi
+
+if [ ! -f "rootfs_v1.img" ]; then
+    wget https://storage.googleapis.com/kernelctf-build/files/rootfs_v1.img.gz
+    gzip -d rootfs_v1.img.gz
+fi
+
+if [ ! -f "ramdisk_v1.img" ]; then wget https://storage.googleapis.com/kernelctf-build/files/ramdisk_v1.img; fi
+if [ ! -f "flag" ]; then echo "kernelCTF{example_flag}" > flag; fi
+
+exec ./qemu_v2.sh "releases/$RELEASE_NAME" flag "$INIT_FN"