#!/usr/bin/env bash

# Microsoft Azure Linux Agent
#
# Copyright 2018 Microsoft Corporation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

#
# Returns the path for the 'waagent' command.
#
set -euo pipefail

# On most distros, 'waagent' is in PATH
if which waagent 2> /dev/null; then
  exit 0
fi

# if the agent is running, get the path from 'cmdline' in the /proc file system
if test -e /run/waagent.pid; then
  cmdline="/proc/$(cat /run/waagent.pid)/cmdline"
  if test -e "$cmdline"; then
    # cmdline is a sequence of null-terminated strings; break into lines and look for waagent
    if tr '\0' '\n' < "$cmdline" | grep waagent; then
      exit 0
    fi
  fi
fi

# try some well-known locations
declare -a known_locations=(
  "/usr/sbin/waagent"
  "/usr/share/oem/bin/waagent"
)

for path in "${known_locations[@]}"
do
    if [[ -e $path ]]; then
      echo "$path"
      exit 0
    fi
done

echo "Can't find the path for the 'waagent' command" >&2
exit 1
