Re: V3 [PATCH 4/4] Add a skeleton for init scripts

[Darren Hart <dvhart@linux.intel.com>]

On 05/16/2011 07:40 PM, Robert Yang wrote:
> Add a skeleton for init scripts, the original structure is from
> /etc/init.d/skeleton of Ubuntu 10.10, it is in sysvinit_2.87dsf, so add
> the COPYRIGHT(GPLv2) of sysvinit_2.87dsf. Modified the original skeleton
> a lot to make it as easy as possible, just use posix shell command, and
> have tested it with core-image-minimal.
> 
> * The skeleton implements the following actions:
>   - start, stop, restart, status, try-restart and force-reload.
>     # force-reload is a alias of try-restart.
> 
>   - not implements reload, since only a few programs have it, just leave
>     it as placeholder.
> 
> * Add /usr/sbin/skeleton-test to test /etc/init.d/skeleton
> 
> * The /etc/init.d/skeleton can be run and output the example messages:
>   1) #./skeleton start (test start)
>      Starting skeleton ...
> 
>   2) #./skeleton start (test start again when running)
>      skeleton already running (1078).
> 
>   3) #./skeleton status (test status when running)
>      skeleton is running (1078).
> 
>   4) #./skeleton stop (test stop)
>      Stopped skeleton (1078).
> 
>   5) #./skeleton stop (test stop again)
>      skeleton is not running; none killed.
> 
>   6) #./skeleton status (test status when stopped)
>      skeleton is not running.
> 
>   7) #./skeleton restart (test restart when running)
>      Stopped skeleton (1128).
>      Starting skeleton ...
> 
>   8) #./skeleton restart (test restart when stopped)
>      skeleton is not running; none killed.
>      Starting skeleton ...
> 
>   9)  try-restart (or force-reload) means restart the service if the
>       service is already running
> 
>      #./skeleton try-restart (test try-restart when stopped)
>      skeleton is not running; none killed.
> 
>      #./skeleton try-restart (test try-restart when running)
>       Stopped skeleton (1181).
>       Starting skeleton ...
> 
> * Have used syslogd to test it in a real world(with both
>   core-image-minimal and core-image-sato)
> 
> Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
> ---
>  .../recipes-skeleton/service/service/COPYRIGHT     |   15 ++
>  .../recipes-skeleton/service/service/skeleton      |  193 ++++++++++++++++++++
>  .../service/service/skeleton_test.c                |   11 +
>  .../recipes-skeleton/service/service_0.1.bb        |   32 ++++
>  4 files changed, 251 insertions(+), 0 deletions(-)
>  create mode 100644 meta-skeleton/recipes-skeleton/service/service/COPYRIGHT
>  create mode 100644 meta-skeleton/recipes-skeleton/service/service/skeleton
>  create mode 100644 meta-skeleton/recipes-skeleton/service/service/skeleton_test.c
>  create mode 100644 meta-skeleton/recipes-skeleton/service/service_0.1.bb
> 
> diff --git a/meta-skeleton/recipes-skeleton/service/service/COPYRIGHT b/meta-skeleton/recipes-skeleton/service/service/COPYRIGHT
> new file mode 100644
> index 0000000..ec3e171
> --- /dev/null
> +++ b/meta-skeleton/recipes-skeleton/service/service/COPYRIGHT
> @@ -0,0 +1,15 @@
> +Sysvinit is Copyright (C) 1991-2004 Miquel van Smoorenburg
> +
> +    This program is free software; you can redistribute it and/or modify
> +    it under the terms of the GNU General Public License as published by
> +    the Free Software Foundation; either version 2 of the License, or
> +    (at your option) any later version.
> +
> +    This program is distributed in the hope that it will be useful,
> +    but WITHOUT ANY WARRANTY; without even the implied warranty of
> +    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +    GNU General Public License for more details.
> +
> +    You should have received a copy of the GNU General Public License
> +    along with this program; if not, write to the Free Software
> +    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
> diff --git a/meta-skeleton/recipes-skeleton/service/service/skeleton b/meta-skeleton/recipes-skeleton/service/service/skeleton
> new file mode 100644
> index 0000000..a3edc9d
> --- /dev/null
> +++ b/meta-skeleton/recipes-skeleton/service/service/skeleton
> @@ -0,0 +1,193 @@
> +#! /bin/sh
> +### BEGIN INIT INFO
> +# Provides:          skeleton
> +# Required-Start:    $local_fs
> +# Should-Start:
> +# Required-Stop:     $local_fs
> +# Should-Stop:
> +# Default-Start:     2 3 4 5
> +# Default-Stop:      0 1 6
> +# Short-Description: Example initscript
> +# Description:       This file should be used to construct scripts to be
> +#                    placed in /etc/init.d
> +### END INIT INFO
> +
> +# The definition of actions: (From LSB 3.1.0)
> +# start         start the service
> +# stop          stop the service
> +# restart       stop and restart the service if the service is already running,
> +#               otherwise start the service
> +# try-restart	restart the service if the service is already running
> +# reload	cause the configuration of the service to be reloaded without
> +#               actually stopping and restarting the service
> +# force-reload	cause the configuration to be reloaded if the service supports
> +#               this, otherwise restart the service if it is running
> +# status	print the current status of the service
> +
> +# The start, stop, restart, force-reload, and status actions shall be supported
> +# by all init scripts; the reload and the try-restart actions are optional
> +
> +# Common steps to convert this skeleton into a real init script
> +# 1) cp skeleton <the_real_name>
> +# 2) Set DESC and NAME
> +# 3) Check whether the daemon app is /usr/sbin/$NAME, if not, set it.
> +# 4) Set DAEMON_ARGS if there is any
> +# 5) Remove the useless code
> +
> +# NOTE: The skeleton doesn't support the daemon which is a script unless the
> +#       pidof supports "-x" option, please see more comments for pidofproc ()
> +#       in /etc/init.d/functions
> +
> +# PATH should only include /usr/* if it runs after the mountnfs.sh script
> +PATH=/sbin:/usr/sbin:/bin:/usr/bin
> +
> +DESC="skeleton"
> +NAME="skeleton-test"
> +DAEMON=/usr/sbin/$NAME
> +DAEMON_ARGS=""
> +PIDFILE=/var/run/$NAME.pid
> +
> +. /etc/init.d/functions || exit 1
> +
> +# Exit if the package is not installed
> +[ -x "$DAEMON" ] || exit 0
> +
> +# Read configuration variable file if it is present
> +[ -r /etc/default/$NAME ] && . /etc/default/$NAME
> +
> +#
> +# Function that starts the daemon/service
> +#
> +do_start() {
> +	local status pid
> +
> +	status=0
> +	pid=`pidofproc $NAME` || status=$?
> +	case $status in
> +	0)
> +		echo "$DESC already running ($pid)."
> +		exit 1
> +		;;
> +	*)
> +		echo "Starting $DESC ..."
> +		exec $DAEMON $DAEMON_ARGS >/dev/null 2>&1 || status=$?
> +		echo "ERROR: Failed to start $DESC."
> +		exit $status
> +		;;
> +	esac
> +
> +	# Add code here, if necessary, that waits for the process to be ready
> +	# to handle requests from services started subsequently which depend
> +	# on this one.  As a last resort, sleep for some time.
> +}
> +
> +#
> +# Function that stops the daemon/service
> +#
> +do_stop() {
> +	local pid status
> +
> +	status=0
> +	pid=`pidofproc $NAME` || status=$?
> +	case $status in
> +	0)
> +		# Exit when fail to stop, the kill would complain when fail
> +		kill -s 15 $pid >/dev/null && rm -f $PIDFILE && \
> +			echo "Stopped $DESC ($pid)." || exit $?
> +		;;
> +	*)
> +		echo "$DESC is not running; none killed." >&2
> +		;;
> +	esac
> +
> +	# Wait for children to finish too if this is a daemon that forks
> +	# and if the daemon is only ever run from this initscript.
> +	# If the above conditions are not satisfied then add some other code
> +	# that waits for the process to drop all resources that could be
> +	# needed by services started subsequently.  A last resort is to
> +	# sleep for some time.
> +	return $status
> +}
> +
> +#
> +# Function that sends a SIGHUP to the daemon/service
> +#
> +do_reload() {
> +	local pid status
> +
> +	status=0
> +        # If the daemon can reload its configuration without
> +        # restarting (for example, when it is sent a SIGHUP),
> +        # then implement that here.
> +	pid=`pidofproc $NAME` || status=$?
> +	case $status in
> +	0)
> +		echo "Reloading $DESC ..."
> +		kill -s 1 $pid || exit $?
> +		;;
> +	*)
> +		echo "$DESC is not running; none reloaded." >&2
> +		;;
> +	esac
> +	exit $status
> +}
> +
> +
> +#
> +# Function that shows the daemon/service status
> +#
> +status_of_proc () {
> +	local pid status
> +
> +	status=0
> +	# pidof output null when no program is running, so no "2>/dev/null".
> +	pid=`pidofproc $NAME` || status=$?
> +	case $status in
> +	0)
> +		echo "$DESC is running ($pid)."
> +		exit 0
> +		;;
> +	*)
> +		echo "$DESC is not running." >&2
> +		exit $status
> +		;;
> +	esac
> +}
> +
> +case "$1" in
> +start)
> +	do_start
> +	;;
> +stop)
> +	do_stop || exit $?
> +	;;
> +status)
> +	status_of_proc
> +	;;
> +restart)
> +	# Always start the service regardless the status of do_stop
> +	do_stop
> +	do_start
> +	;;
> +try-restart|force-reload)
> +	# force-reload is the same as reload or try-restart according
> +	# to its definition, the reload is not implemented here, so
> +	# force-reload is the alias of try-restart here, but it should
> +	# be the alias of reload if reload is implemented.
> +	#
> +	# Only start the service when do_stop succeeds
> +	do_stop && do_start
> +	;;
> +#reload)
> +	# If the "reload" action is implemented properly, then let the
> +	# force-reload be the alias of reload, and remove it from
> +	# try-restart|force-reload)
> +	#
> +	#do_reload
> +	#;;
> +*)
> +	echo "Usage: $0 {start|stop|status|restart|try-restart|force-reload}" >&2
> +	exit 3
> +	;;
> +esac
> +
> diff --git a/meta-skeleton/recipes-skeleton/service/service/skeleton_test.c b/meta-skeleton/recipes-skeleton/service/service/skeleton_test.c
> new file mode 100644
> index 0000000..465d430
> --- /dev/null
> +++ b/meta-skeleton/recipes-skeleton/service/service/skeleton_test.c
> @@ -0,0 +1,11 @@
> +#include <unistd.h>
> +
> +/* This demo does nothing except for testing /etc/init.d/skeleton */
> +

There aren't a lot of .c examples in our repository, and those we do
have do not serve as good examples of C formatting. Let's make sure this
one starts off right:

> +int

typically best to start with the type, although not entirely necessary.
For this example though, there is no advantage to splitting the type
from the function name.

> +main () {

Function braces should start on a new line
No need for a gap between function and argument parenthetical
Include the proper signature for main, even if you aren't using it.

> +	daemon (0, 0);
> +	while (1) {

space between condition keyword and parenthetical is appropriate.

> +		sleep (1);
> +	}

main returns an int, be sure to provide a proper return otherwise the
caller just reads garbage from the stack (or it would if it ever
returned ;-)

> +}



In summary:

int main(int argc, char *argv[]) {
	daemon(0, 0);
	while (1) {
		sleep(1);
	}
	return 0;
}

Thanks,

Darren

> diff --git a/meta-skeleton/recipes-skeleton/service/service_0.1.bb b/meta-skeleton/recipes-skeleton/service/service_0.1.bb
> new file mode 100644
> index 0000000..22137a5
> --- /dev/null
> +++ b/meta-skeleton/recipes-skeleton/service/service_0.1.bb
> @@ -0,0 +1,32 @@
> +DESCRIPTION = "The canonical example of init scripts"
> +SECTION = "base"
> +LICENSE = "GPLv2"
> +LIC_FILES_CHKSUM = "file://${WORKDIR}/COPYRIGHT;md5=349c872e0066155e1818b786938876a4"
> +RDEPENDS_${PN} = "initscripts"
> +PR = "r0"
> +
> +SRC_URI = "file://skeleton \
> +	   file://skeleton_test.c \
> +	   file://COPYRIGHT \
> +	   "
> +
> +CONFFILES_${PN} += "${sysconfdir}/init.d/skeleton"
> +
> +do_compile () {
> +	${CC} ${WORKDIR}/skeleton_test.c -o ${WORKDIR}/skeleton-test
> +}
> +
> +do_install () {
> +	install -d ${D}${sysconfdir}/init.d
> +	cat ${WORKDIR}/skeleton | \
> +	  sed -e 's,/etc,${sysconfdir},g' \
> +	      -e 's,/usr/sbin,${sbindir},g' \
> +	      -e 's,/var,${localstatedir},g' \
> +	      -e 's,/usr/bin,${bindir},g' \
> +	      -e 's,/usr,${prefix},g' > ${D}${sysconfdir}/init.d/skeleton
> +	chmod a+x ${D}${sysconfdir}/init.d/skeleton
> +
> +	install -d ${D}${sbindir}
> +	install -m 0755 ${WORKDIR}/skeleton-test ${D}${sbindir}/
> +}
> +

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel