linux/install_service/install_service.sh

	install_service.sh revision e2def7e73a45db215192dc910e9388cd08f5b2e8
#!/bin/sh

#
# Script to install services within a VirtualBox installation.
#
# Copyright (C) 2012 Oracle Corporation
#
# This file is part of VirtualBox Open Source Edition (OSE), as
# available from http://www.virtualbox.org. This file is free software;
# you can redistribute it and/or modify it under the terms of the GNU
# General Public License (GPL) as published by the Free Software
# Foundation, in version 2 as it comes in the "COPYING" file of the
# VirtualBox OSE distribution. VirtualBox OSE is distributed in the
# hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.

# Clean up before we start.
cr="
"
tab="   "
IFS=" ${cr}${tab}"
'unset' -f unalias
'unalias' -a 2>/dev/null
'unset' -f command
PATH=/bin:/sbin:/usr/bin:/usr/sbin:$PATH

# Get the folder we are running from, as we need other files there.
script_folder="`dirname "$0"`"

## Script usage documentation.
usage() {
  cat << EOF
Usage:

  `basename $0` --help|--enable|--disable|--force-enable|--force-disable
                      |--remove <options>

Create a system service which runs a command.  In order to make it possible to
do this in a simple and portable manner, we place a number of requirements on
the command to be run:
 - That it can be started safely even if all its dependencies are not started
   and will sleep if necessary until it can start work.  Ideally it should start
   accepting input as early as it can, but delay handling it if necessary.
 - That it does not background to simplify service process management.
 - That it can be safely shut down using SIGTERM.
 - That if all running copies of the main process binary are stopped first the
   service can be re-started and will do any necessary clean-up automatically.
 - That any output which must not be lost go either to the system log or to the
   service's private log.

We currently support System V init only.  This will probably soon be extended
to BSD init, OpenRC, Pardus Comar and systemd, but probably not Upstart which
currently requires modifying init files to disable a service.  We also try to
enable our service (if requested) in all init systems we find, as we do not know
which one is in active use.  We assume that this will not have any adverse
effects.

 --help|--usage
     Print this help text and exit.

  --enable|--disable|--force-enable|--force-disable
      These actions install the service.  If a version of the service was not
      installed previously, "--enable" and "--force-enable" make it start when
      entering normal user run-levels and "--disable" and "--force-disable"
      prevents it from starting when entering any run-level.  If a version of
      the service was already installed previously, "--enable" and "--disable"
      simply update it without changing when it starts; "--force-enable" and
      "--force-disable" behave the same as when no previous version was found.
      Only one of these options or "--remove" may be specified.

  --remove
      This action uninstalls the service.  It may not be used in combination
      with "--enable", "--disable", "--force-enable" or "--force-disable".

Basic options:

  --prefix <prefix>
      Treat all paths as relative to <prefix> rather than /etc.

Required service options:

EOF
    "${script_folder}/../helpers/generate_service_file" --list-options
}

## The function definition at the start of every non-trivial shell script!
abort() {
    ## $1 Error text to output to standard error.
    cat >&2 << EOF
$1
EOF
    exit 1
}

ACTION=""
PREFIX="/etc/"
ARGUMENTS=""
SERVICE_NAME=""

# Process arguments.
## @todo Pass more through unmodified to generate_service_file to reduce
#        duplication.  Or then again, maybe the hassle of perserving the
#        positional parameters is not worth it.
while test x"${#}" != "x0"; do
    case "${1}" in
    "--help"|"--usage")
        usage
        exit 0;;
    "--enable"|"--disable"|"--force-enable"|"--force-disable"|"--remove")
        test -z "${ACTION}" || abort "More than one action specified."
        ACTION="true"
        ENABLE=""
        INSTALL="true"
        UPDATE=""
        { test "${1}" = "--enable" || test "${1}" = "--disable"; } &&
            UPDATE="true"
        { test "${1}" = "--enable" || test "${1}" = "--force-enable"; } &&
            ENABLE="true"
        test "${1}" = "--remove" &&
            INSTALL=""
        shift;;
    "--prefix")
        test -z "${2}" && abort "${1}: missing argument."
        PREFIX="${2}"
        shift 2;;
    "--command")
        test -z "${2}" && abort "${1}: missing argument."
        COMMAND="${2}"
        shift 2;;
    "--arguments")
        test -z "${2}" && abort "${1}: missing argument."
        ARGUMENTS="${2}"
        shift 2;;
    "--description")
        test -z "${2}" && abort "${1}: missing argument."
        DESCRIPTION="${2}"
        shift 2;;
    "--service-name")
        test -z "${2}" && abort "${1}: missing argument."
        SERVICE_NAME="${2}"
        shift 2;;
    *)
        abort "Unknown option ${1}.";;
    esac
done

# Check required options and set default values for others.
test -z "${ACTION}" &&
    abort "Please supply an install action."
if test -n "${INSTALL}"; then
    test -z "${COMMAND}" &&
        abort "Please supply a start command."
    test -f "${COMMAND}" && test -x "${COMMAND}" ||
        abort "The start command must be an executable file."
    case "${COMMAND}" in
        /*) ;;
        *) abort "The start command must have an absolute path." ;;
    esac
    test -z "${DESCRIPTION}" &&
        abort "Please supply a service description."
else
    test -z "${COMMAND}" && test -z "${SERVICE_NAME}" &&
        abort "Please supply a service name or a start command."
fi
# Get the service name from the command path if not explicitly
# supplied.
test -z "${SERVICE_NAME}" &&
    SERVICE_NAME="`expr "${COMMAND}" : '.*/\(.*\)\..*'`"
test -z "${SERVICE_NAME}" &&
    SERVICE_NAME="`expr "${COMMAND}" : '.*/\(.*\)'`"

# Keep track of whether we found at least one initialisation system.
found_init=""

# Find the best System V/BSD init path if any is present.
for path in "${PREFIX}/init.d/rc.d" "${PREFIX}/init.d/" "${PREFIX}/rc.d/init.d" "${PREFIX}/rc.d"; do
    if test -d "${path}"; then
        test -w "${path}" || abort "No permission to write to \"${path}\"."
        for i in rc0.d rc1.d rc6.d rc.d/rc0.d rc.d/rc1.d rc.d/rc6.d; do
            if test -d "${PREFIX}/${i}"; then
                test -w "${PREFIX}/${i}" ||
                    abort "No permission to write to \"${PREFIX}/${i}\"".
            fi
        done
        found_init="true"
        update=""
        test -f "${path}/${SERVICE_NAME}" && update="${UPDATE}"
        if test -n "${INSTALL}"; then
            "${script_folder}/../helpers/generate_service_file" --format shell --command "${COMMAND}" --arguments "${ARGUMENTS}" --description "${DESCRIPTION}" --service-name "${SERVICE_NAME}" < "${script_folder}/init_template.sh" > "${path}/${SERVICE_NAME}"
            chmod a+x "${path}/${SERVICE_NAME}"
        else
            rm "${path}/${SERVICE_NAME}"
        fi
        # Attempt to install using both system V symlinks and OpenRC, assuming
        # that both will not be in operation simultaneously (but may be
        # switchable).  BSD init expects the user to enable services explicitly.
        if test -z "${update}"; then
            # Various known combinations of sysvinit rc directories.
            for i in "${PREFIX}"/rc*.d/[KS]??"${SERVICE_NAME}" "${PREFIX}"/rc.d/rc*.d/[KS]??"${SERVICE_NAME}"; do
                rm -f "$i"
            done
            # And OpenRC.
            type rc-update > /dev/null 2>&1 &&
                rc-update del "${1}" > /dev/null 2>&1
            # Various known combinations of sysvinit rc directories.
            if test -n "${ENABLE}"; then
                for i in rc0.d rc1.d rc6.d rc.d/rc0.d rc.d/rc1.d rc.d/rc6.d; do
                    if test -d "${PREFIX}/${i}"; then
                        # Paranoia test first.
                        test -d "${PREFIX}/${i}/K80${SERVICE_NAME}" ||
                            ln -sf "${path}/${SERVICE_NAME}" "${PREFIX}/${i}/K80${SERVICE_NAME}"
                    fi
                done
                for i in rc.d rc3.d rc4.d rc5.d rc.d/rc2.d rc.d/rc3.d rc.d/rc4.d rc.d/rc5.d; do
                    if test -d "${PREFIX}/${i}"; then
                        # Paranoia test first.
                        test -d "${PREFIX}/${i}/S20${SERVICE_NAME}" ||
                            ln -sf "${path}/${SERVICE_NAME}" "${PREFIX}/${i}/S20${SERVICE_NAME}"
                    fi
                done
                # And OpenRC.
                type rc-update > /dev/null 2>&1 &&
                    rc-update add "${1}" default > /dev/null 2>&1
            fi
        fi
        break
    fi
done

test -z "${found_init}" &&
    abort "No supported initialisation system found."
exit 0