# Copyright 2018 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

description    "Start the wilco_dtc daemon"
author         "chromium-os-dev@chromium.org"

# Start the wilco_dtc daemon (diagnostics and telemetry collector), which is
# responsible for processing and analyzing telemetry and diagnostics information
# obtained from wilco_dtc_supportd. `wilco_dtc_dispatcher` will manage the
# lifecycle of both this process and wilco_dtc_supportd.
start on starting wilco_dtc_dispatcher
stop on stopped wilco_dtc_dispatcher

respawn
# If the job respawns 3 times in 10 seconds, stop trying.
respawn limit 3 10

env MAITRED_LISTEN_PORT=7788
env MAITRED_PORT=8888
env VM_CPUS=1
env VM_MEM=64
env VM_CID=512
env VM_PATH=/opt/wilco/dtc-vm
env RUNTIME_PATH=/run/wilco-vm
env STORAGE_PATH=/var/lib/wilco
env STORAGE_FILE=/var/lib/wilco/storage.img

pre-start script
  # Make sure the vsock module is loaded.
  modprobe -q vhost-vsock

  # Create the runtime directory.
  if [ -d "${RUNTIME_PATH}" ]; then
    rm -r "${RUNTIME_PATH}"
  fi
  mkdir "${RUNTIME_PATH}"
  chown -R wilco_dtc:wilco_dtc "${RUNTIME_PATH}"

  # Create persistent VM storage if it does not exist.
  if [ ! -d "${STORAGE_PATH}" ]; then
    mkdir -p "${STORAGE_PATH}"
  fi

  if [ ! -f "${STORAGE_FILE}" ]; then
    truncate  --size 32M "${STORAGE_FILE}"
    mkfs.ext4 "${STORAGE_FILE}"
    chown wilco_dtc:wilco_dtc "${STORAGE_FILE}"
  fi

end script

# Used jailing parameters:
#   -e: new network namespace;
#   -i: exit after forking;
#   -l: new IPC namespace;
#   -n: the no_new_privs bit;
#   -p: new PID namespace;
#   -r: remount /proc readonly;
#   -t: a new tmpfs filesystem for /tmp;
#   -v: new VFS namespace;
#   --uts: new UTS/hostname namespace;
#   -u, -g: user account and group;
#   -G: inherit supplementary groups;
#   --mount-dev: a new /dev mount;
#   --profile: minimalistic mount namespace;
#   -k /run: a new tmpfs filesystem for /run, with the subsequent parameters
#       mounting specific files into this directory;
#   -k /var: a new tmpfs filesystem for /var
#   -b /dev/chromeos-low-mem: crosvm can alert system of low memory;
#   -b /dev/log: provide minijail log access;
#   -b /dev/kvm: give access to crosvm to start VMs;
#   -b /dev/vhost-vsock: give access for VM communication;
#   -b ${STORAGE_PATH}: give access to persistent storage;
#   -b ${DIAGNOSTICS_PARTITION}: give read only access to diagnostics partition;
#   -b ${RUNTIME_PATH}: temporary directories to create VM sock
script

  # Give wilco_dtc permission to read the diagnostics parition
  DIAGNOSTICS_PARTITION="$(cgpt find -l DIAGNOSTICS $(rootdev -d -s) | head -1)"
  setfacl -m u:wilco_dtc:r "${DIAGNOSTICS_PARTITION}"

  exec minijail0 -e -l -n -p -r -t -v --uts \
    -u wilco_dtc -g wilco_dtc \
    -G \
    --mount-dev \
    --profile=minimalistic-mountns \
    -k 'tmpfs,/run,tmpfs,MS_NODEV|MS_NOSUID|MS_NOEXEC,mode=755,size=10M' \
    -k 'var,/var,tmpfs,MS_NODEV|MS_NOSUID|MS_NOEXEC,mode=755,size=32M' \
    -b /dev/chromeos-low-mem \
    -b /dev/log \
    -b /dev/kvm,,1 \
    -b /dev/vhost-vsock,,1 \
    -b "${STORAGE_PATH}",,1 \
    -b "${DIAGNOSTICS_PARTITION}" \
    -b "${RUNTIME_PATH}",,1 \
    -- /usr/bin/crosvm run \
         -r "${VM_PATH}"/vm_rootfs.img \
         -p maitred.listen_port="${MAITRED_LISTEN_PORT}" \
         -p printk.devkmsg=on \
         --serial num=1,type=syslog,console=false \
         --syslog-tag wilco_dtc \
         -c "${VM_CPUS}" \
         -m "${VM_MEM}" \
         -s "${RUNTIME_PATH}" \
         --cid "${VM_CID}" \
         -d "${DIAGNOSTICS_PARTITION}" \
         --rwdisk "${STORAGE_FILE}" \
         "${VM_PATH}"/vm_kernel
end script

post-start script
  # Default cpu.shares is 1024. Limit the Wilco VM to 1/8th of that.
  cgroup_dir="/sys/fs/cgroup/cpu/wilco-dtc"
  mkdir -p "${cgroup_dir}"
  echo $(status | cut -f 4 -d ' ') > "${cgroup_dir}/tasks"
  echo 128 > "${cgroup_dir}/cpu.shares"
end script

pre-stop script
  maitred_client --cid=512 --port=8888 --shutdown
end script