#!/bin/bash
# Copyright 2017 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

#### CATEGORY=Device management
### reboot a target fuchsia system

## usage: fx reboot [-r|--recovery] [-b|--bootloader]
##   -r|--recovery   Reboot into recovery image
##   -b|--bootloader Reboot into bootloader
##
## This will reboot the device specified with `fx set-device`; otherwise
## one of the devices on the link-local network.

set -e

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/lib/vars.sh || exit $?
fx-config-read

function usage() {
    fx-command-help
}

reboot_type="reboot"
while [[ "$1" =~ ^- ]]; do
  case "$1" in
  -h|--help)
    usage
    exit 0
    ;;
  -r|--recovery)
    reboot_type="reboot-recovery"
    ;;
  -b|--bootloader)
    reboot_type="reboot-bootloader"
    ;;
  *)
    break
  esac
  shift
done

if [[ $# -gt 1 ]]; then
  usage
  exit 1
fi

timeout_flag="--nowait"

device=$(get-device-name)
if [[ -z ${device} ]] &&
   [[ $("${ZIRCON_TOOLS_DIR}/netls" "${timeout_flag}" | grep -i -c "device ") > "1" ]] ; then
  echo "Rebooting some device... Consider using \`fx set-device\` if you have multiple devices."
else
  echo "Rebooting ${device}..."
fi

"${ZIRCON_TOOLS_DIR}/netruncmd" "${timeout_flag}" "${device}" "dm ${reboot_type}"

# Check that the device is reachable over SSH, otherwise let the user know.
# This establishes a ControlMaster.
monotime=$(fx-command-run shell clock --monotonic)
if [[ $? -ne 0 ]]; then
  fx-error "Could not reach ${device} over SSH"
  exit 1
fi

# Note: the background and exit trick here loosely gives us a "successful"
# command completion, provided the shell parses our input. As dm reboot is
# synchronous, we can't wait for it to complete, as the shell/ssh get no
# shutdown message, and will simply observe a peer connection dropping.
# Sometimes the reboot races the exit, in which case this command also exits
# with error, but the following SSH check will fail (provided the device
# doesn't reboot to SSH in less than a few seconds), so the loop will exit with
# success.
fx-command-run shell "dm \"${reboot_type}\" & exit 0"

# Wait for the SSH connection to go down. As we use ControlMaster, we can
# observe this using the control master check.
i=0
while fx-command-run shell -O check > /dev/null 2>&1; do
  if [[ "$monotime" -gt $(fx-command-run shell clock --monotonic) ]]; then
    # If we get here, then we raced between reboot and check, the device
    # rebooted so fast that someone reconnected our SSH ControlMaster before we
    # observed it going down (this generally only happens if the 'exit 0' above
    # also races, and `fx serve` is busy trying to re-connect).
    exit 0
  fi

  sleep 0.5
  if [[ "$((i++))" -gt "10" ]]; then
    fx-error "SSH still connected after $((i/2))s, reboot may have failed"
    exit 1
  fi
done