diagnostics/init/cros_healthd.conf

# Copyright 2019 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 cros_healthd daemon"
author         "chromium-os-dev@chromium.org"

# Start the cros_healthd daemon, which is responsible for reporting telemetry
# data and running diagnostics.
start on starting system-services
stop on stopping system-services

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

expect fork

pre-start script
  # Prepare directory for diagnostics routine test files.
  mkdir -p /var/cache/diagnostics
  chown cros_healthd:cros_healthd /var/cache/diagnostics
end script

# Used jailing parameters:
#   -e: new network namespace;
#   -G: inherit supplementary groups;
#   -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;
#   -P: set /mnt/empty as rootfs;
#   -b: bind /, /proc and /dev. /dev is necessary to send ioctls to the system's
#       block devices.
#   -k /run: a new tmpfs filesystem for /run, with the subsequent parameters
#       mounting specific files into this directory;
#   -b /run/dbus: shared socket file for talking with the D-Bus daemon;
#   -b /run/systemd/journal: needed for logging;
#   -b /run/chromeos-config/v1: needed for access to chromeos-config;
#   -k /sys: a new tmpfs filesystem for /sys, with the subsequent parameters
#       mounting specific files into this directory;
#   -b /sys/class/backlight: files related to the system's backlights;
#   -b /sys/class/block: files related to the system's block devices;
#   -b /sys/class/chromeos: files related to Chrome OS hardware devices;
#   -b /sys/class/power_supply: files related to the system's power supplies;
#   -b /sys/devices: needed to get the names of the block device dev nodes;
#   -b /sys/firmware/vpd/ro: files with cached VPD;
#   -k /var: new tmpfs for var, with the subsequent parameters
#       mounting specific files into this directory;
#   -b /var/lib/timezone: symlink for reading the timezone file;
#   -b /usr/share/zoneinfo: directory holding timezone files;
#   -b /sys/devices/system/cpu: directory of both global and individual CPU
#       attributes which used to diagnose the CPU by the stressapptest.
#   -b /dev/shm: allows creation of shared memory files that are used to set up
#       mojo::ScopedHandles which can be returned by GetRoutineUpdate.
#   -b /var/cache/diagnostics: allow test routine to create a test
#       file under filesystem;
#   -S: apply seccomp filters.
script
  # Evaluate which directories are present for binding. Do this without starting
  # subshells to avoid breaking upstart's PID tracking.
  set --
  if [ -e /sys/class/backlight ]; then
    set -- "$@" -b /sys/class/backlight
  fi
  if [ -e /sys/class/chromeos ]; then
    set -- "$@" -b /sys/class/chromeos
  fi
  if [ -e /sys/class/power_supply ]; then
    set -- "$@" -b /sys/class/power_supply
  fi
  if [ -e /sys/firmware/vpd/ro ]; then
    set -- "$@" -b /sys/firmware/vpd/ro
  fi

  exec minijail0 -e -G -i -l -n -p -r -t -v --uts \
    -u cros_healthd -g cros_healthd \
    -P /mnt/empty \
    -b / -b /proc -b /dev \
    -k 'tmpfs,/run,tmpfs,MS_NODEV|MS_NOSUID|MS_NOEXEC,mode=755,size=10M' \
    -b /run/dbus -b /run/systemd/journal \
    -b /run/chromeos-config/v1 \
    -k 'tmpfs,/sys,tmpfs,MS_NODEV|MS_NOSUID|MS_NOEXEC,mode=755,size=10M' \
    -b /sys/class/block -b /sys/devices \
    -b /usr/share/zoneinfo \
    -k 'tmpfs,/var,tmpfs,MS_NODEV|MS_NOSUID|MS_NOEXEC,mode=755,size=10M' \
    -b /var/lib/timezone \
    -b /sys/devices/system/cpu \
    -b /dev/shm,,1 \
    "$@" \
    -b /var/cache/diagnostics,,1 \
    -S /usr/share/policy/cros_healthd-seccomp.policy \
    -- /usr/bin/cros_healthd
end script

# Wait for daemon to claim its D-Bus name before transitioning to started.
post-start exec minijail0 -u cros_healthd -g cros_healthd /usr/bin/gdbus \
    wait --system --timeout 15 org.chromium.CrosHealthd