[env/kvm] Launch task script, if any, on student SSH login

base-containers/kvm/Dockerfile

@@ -95,7 +95,7 @@ RUN	git clone https://github.com/amluto/virtme &&\
 WORKDIR /
 
 # Get expect script launching the VM
-COPY run.expect setup.sh /
+COPY run.expect setup.sh telnet_login.sh /
 ENV KVM_START_PATH=/run.expect
 
 # Add telnetd config

base-containers/kvm/setup.sh

@@ -1,11 +1,28 @@
 #! /bin/bash -x
 
+# Load env variables
 STUDENT_DIR=/task/student
 KVM_DIR="${STUDENT_DIR}/kvm"
+SCRIPTS_DIR="${STUDENT_DIR}/scripts"
+STUDENT_LOGIN="${SCRIPTS_DIR}/student_login"
 
+# Set kvm group in human-readable way
 groupdel kvm
 groupadd -g $(stat -c '%g' /dev/kvm) kvm
+
+# Create RW dir mounted in the KVM
 mkdir "${KVM_DIR}"
+chown worker:worker /task
 chown worker:worker "${KVM_DIR}"
-cp "${STUDENT_DIR}/scripts/bzImage" /tmp
+
+# Copy the kernel in a path readable by "worker" within the SSH container
+cp "${SCRIPTS_DIR}/bzImage" /tmp
+
+# Copy student_login file, if any, in a path readable by "worker" within the VM
+if [[ -f "${STUDENT_LOGIN}" ]]
+then
+    cp "${STUDENT_LOGIN}" /
+fi
+
+# Launch the KVM as "worker"
 su - worker -G worker -G kvm -c "virtme-run --cpus 2 --memory 256 --kimg /tmp/bzImage --rwdir=/tmp/student=${KVM_DIR}"

base-containers/kvm/telnet

@@ -5,6 +5,6 @@ socket_type = stream
 wait = no
 user = root
 server = /usr/sbin/telnetd
-server_args = -E /bin/bash
+server_args = -E /telnet_login.sh
 disable = no
 }

base-containers/kvm/telnet_login.sh

@@ -0,0 +1,21 @@
+#! /bin/bash
+
+FIRST=/tmp/.first
+STUDENT_LOGIN="/student_login"
+
+if [[ ! -f "${FIRST}" ]]
+then
+    # On first login within the KVM
+    touch "${FIRST}"
+
+    if [[ -f "${STUDENT_LOGIN}" ]]
+    then
+	# If the task specifies a given setup to launch (e.g. a mininet script), run it
+	./"${STUDENT_LOGIN}"
+    else
+	# Else, simply spawn a shell in the KVM
+	/bin/bash
+    fi
+else
+    /bin/bash
+fi