shocker-exec

#!/bin/sh
cgroups='cpu,cpuacct,memory'
btrfs_path='/var/shocker'
dirname=$(dirname "$(readlink -f "$0")")

#shellcheck disable=SC1090
. "$dirname"/utils.sh

usage () {
cat << USAGE
  shocker-exec - run a command inside a container

  Usage: shocker exec <container> <command>

  Options:
   -h, --help output usage information

  Examples:
   $ shocker exec ps_1234 top   # run top inside a running container
USAGE
}

[ "$#" -eq 0 ] && { usage; exit 1; }
case "$1" in
  -h|--help ) usage && exit 1 ;;
esac

shocker_exec() {
  fn_mine () {
    xargs ps ho pid,command \
      < "/sys/fs/cgroup/cpu/$1/tasks" \
      | awk '$2 == "unshare" {print $1}' \
      | xargs pgrep -P | head -1
  }

  cid="$(fn_mine "$1")"
  shocker_log_command "$1" "${@:2}"
  nsenter -t "$cid" -m -u -i -n -p \
    chroot "$btrfs_path/containers/$1" \
    /usr/bin/env -i /bin/sh -c "export PS1=\"\x1b[1m${1} \w\x1b[0m # \"; \
    ${*:2}"
}

cstate=$(get_state "$1")
ctype=$(get_type "$1")

case "$ctype" in
  image    ) printf "'%s' does not exist as a container\n" "$1" >&2; exit 1 ;;
  container)
    case "$cstate" in
      running) shocker_exec "$@" ;;
      stopped) printf "Container '%s' is not running\n" "$1" >&2; exit 1 ;;
      crashed) printf "Container '%s' is not running\n" "$1" >&2; exit 1 ;;
      missing) printf "Container '%s' does not exist\n" "$1" >&2; exit 1 ;;
      *      ) usage; exit 1 ;;
    esac ;;
  unknown  ) printf "Can not determine type of '%s'\n" "$1" >&2; exit 1 ;;
  *        ) usage; exit 1 ;;
esac