#!/bin/sh
# This file is part of cloud-init. See LICENSE file for license information.

DATA_PRE="/var/lib/cloud/sem/bootper"
INST_PRE="/var/lib/cloud/instance/sem/bootper"

Usage() {
    cat << EOF
Usage: ${0##*/} frequency name cmd [ arg1 [ arg2 [ ... ] ]
   run cmd with arguments provided.

   This utility can make it easier to use boothooks or bootcmd
   on a per "once" or "always" basis.

   If frequency is:
      * once: run only once (do not re-run for new instance-id)
      * instance: run only the first boot for a given instance-id
      * always: run every boot

EOF
}
error() { echo "$@" 1>&2; }
fail() {
    [ $# -eq 0 ] || error "$@"
    exit 1
}

# support the old 'cloud-init-run-module freq name "execute" cmd arg1'
# if < 3 arguments, it will fail below on usage.
if [ "${0##*/}" = "cloud-init-run-module" ]; then
    if [ $# -le 2 -o "$3" = "execute" ]; then
        error "Warning: ${0##*/} is deprecated. Please use cloud-init-per."
        freq=$1
        name=$2
        [ $# -le 2 ] || shift 3
        set -- "$freq" "$name" "$@"
    else
        fail "legacy cloud-init-run-module only supported with module 'execute'"
    fi
fi

[ "$1" = "-h" -o "$1" = "--help" ] && {
    Usage
    exit 0
}
[ $# -ge 3 ] || {
    Usage 1>&2
    exit 1
}
freq=$1
name=$(echo $2 | sed 's/-/_/g')
shift 2

[ "${name#*/}" = "${name}" ] || fail "name cannot contain a /"
[ "$(id -u)" = "0" ] || fail "must be root"

case "$freq" in
    once | always) sem="${DATA_PRE}.$name.$freq" ;;
    instance) sem="${INST_PRE}.$name.$freq" ;;
    *)
        Usage 1>&2
        fail "invalid frequency: $freq"
        ;;
esac

[ -d "${sem%/*}" ] || mkdir -p "${sem%/*}" ||
    fail "failed to make directory for ${sem}"

# Rename legacy sem files with dashes in their names. Do not overwrite existing
# sem files to prevent clobbering those which may have been created from calls
# outside of cloud-init.
sem_legacy=$(echo $sem | sed 's/_/-/g')
[ "$sem" != "$sem_legacy" -a -e "$sem_legacy" ] && mv -n "$sem_legacy" "$sem"

[ "$freq" != "always" -a -e "$sem" ] && exit 0
"$@"
ret=$?
printf "%s\t%s\n" "$ret" "$(date +%s)" > "$sem" ||
    fail "failed to write to $sem"
exit $ret
