[reboot] log reboot progress and add a sanity check before reboot (#526)

* [reboot] log reboot progress and add a sanity check before reboot

- Do not reboot device if the next image is not there.
- Log if the filesystem is read-only or full

Signed-off-by: Ying Xie <ying.xie@microsoft.com>

* Remove unnecessary if condition since the purpose is warning and logging

scripts/reboot

@@ -7,11 +7,21 @@ ASIC_TYPE=$(sonic-cfggen -y /etc/sonic/sonic_version.yml -v asic_type)
 DEVPATH="/usr/share/sonic/device"
 PLAT_REBOOT="platform_reboot"
 REBOOT_CAUSE_FILE="/host/reboot-cause/reboot-cause.txt"
+VERBOSE=no
+EXIT_NEXT_IMAGE_NOT_EXISTS=4
+
+function debug()
+{
+ if [[ x"${VERBOSE}" == x"yes" ]]; then
+ echo `date` $@
+ fi
+ logger "$@"
+}
 
 function stop_sonic_services()
 {
  if [[ x"$ASIC_TYPE" != x"mellanox" ]]; then
- echo "Stopping syncd process..."
+ debug "Stopping syncd process..."
  docker exec -i syncd /usr/bin/syncd_request_shutdown --cold > /dev/null
  sleep 3
  fi
@@ -44,13 +54,41 @@ function show_help_and_exit()
  exit 0
 }
 
+function setup_reboot_variables()
+{
+ NEXT_SONIC_IMAGE=$(sonic_installer list | grep "Next: " | cut -d ' ' -f 2)
+ IMAGE_PATH="/host/image-${NEXT_SONIC_IMAGE#SONiC-OS-}"
+}
+
+function reboot_pre_check()
+{
+ # Make sure that the file system is normal: read-write able
+ filename="/host/test-`date +%Y%m%d-%H%M%S`"
+ ERR=0
+ touch ${filename} || ERR=$?
+ if [[ ${ERR} -ne 0 ]]; then
+ # Continue rebooting in this case, but log the error
+ VERBOSE=yes debug "Filesystem might be read-only or full ..."
+ fi
+ rm ${filename}
+
+ # Make sure that the next image exists
+ if [[ ! -d ${IMAGE_PATH} ]]; then
+ VERBOSE=yes debug "Next image ${NEXT_SONIC_IMAGE} doesn't exist ..."
+ exit ${EXIT_NEXT_IMAGE_NOT_EXISTS}
+ fi
+}
+
 function parse_options()
 {
- while getopts "h?" opt; do
+ while getopts "h?v" opt; do
  case ${opt} in
  h|\? )
  show_help_and_exit
  ;;
+ v )
+ VERBOSE=yes
+ ;;
  esac
  done
 }
@@ -63,6 +101,11 @@ if [[ "$EUID" -ne 0 ]]; then
  exit 1
 fi
 
+debug "User requested rebooting device ..."
+
+setup_reboot_variables
+reboot_pre_check
+
 # Stop SONiC services gracefully.
 stop_sonic_services
 
@@ -81,13 +124,13 @@ if [ -x /sbin/hwclock ]; then
 fi
 
 if [ -x ${DEVPATH}/${PLATFORM}/${PLAT_REBOOT} ]; then
- echo "Rebooting with platform ${PLATFORM} specific tool ..."
+ VERBOSE=yes debug "Rebooting with platform ${PLATFORM} specific tool ..."
  exec ${DEVPATH}/${PLATFORM}/${PLAT_REBOOT} $@
 else
  # If no platform-specific reboot tool, just run /sbin/reboot
  exec /sbin/reboot $@
 fi
 
 # Should never reach here
-echo "Reboot failed!" >&2
+VERBOSE=yes debug "Reboot failed!" >&2
 exit 1