qemu guest agent based patching

patchviasocket.sh

#!/bin/bash
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# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you 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
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# specific language governing permissions and limitations
# under the License.

set -e

while getopts "n:p:h" opt; do
  case ${opt} in
    n )
      name=$OPTARG
      ;;
    p )
      cmdline=$(echo $OPTARG | tr '%' ' ' | base64 -w 0)
      ;;
    h )
      echo "Usage: $0 -n [VM name] -p [command line]"
      exit 0
      ;;
  esac
done

SOCK_FILE="/var/lib/libvirt/qemu/${name}.agent"
SSHKEY_FILE="/root/.ssh/id_rsa.pub.cloud"

if [ ! -e $SOCK_FILE ]; then
    echo "Socket file $SOCK_FILE not found!"
    exit 1
fi

if [ ! -e $SSHKEY_FILE ]; then
    echo "SSH public key file $SSHKEY_FILE not found!"
    exit 1
fi

while ! virsh qemu-agent-command $name '{"execute":"guest-ping"}' >/dev/null 2>&1
do
    sleep 0.1
done

while [ $(virsh qemu-agent-command $name '{"execute":"guest-sync","arguments":{"id":1234567890}}' 2>/dev/null) != '{"return":1234567890}' ]
do
    sleep 0.1
done

write_file() {
    local name=${1}
    local path=${2}
    local content=${@:3}
    fd=$(virsh qemu-agent-command $name "{\"execute\":\"guest-file-open\", \"arguments\":{\"path\":\"$path\",\"mode\":\"w+\"}}" | sed 's/[^:]*:\([^}]*\).*/\1/')
    virsh qemu-agent-command $name "{\"execute\":\"guest-file-write\", \"arguments\":{\"handle\":$fd,\"buf-b64\":\"$content\"}}" > /dev/null
    virsh qemu-agent-command $name "{\"execute\":\"guest-file-close\", \"arguments\":{\"handle\":$fd}}" > /dev/null
}

# Write cmdline payload
write_file $name "/var/cache/cloud/cmdline" $cmdline
# Write ssh public key
write_file $name "/root/.ssh/authorized_keys" $(cat $SSHKEY_FILE | base64 -w 0)
# Fix ssh public key permission
virsh qemu-agent-command $name '{"execute":"guest-exec","arguments":{"path":"chmod","arg":["go-rwx","/root/.ssh/authorized_keys"]}}' > /dev/null