Gllin

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gllin is an userpsace driver for a hammerhead GPS chip. It was distributed on phase1 openmokos.

Thanks to a tremendous amount of hard work by many people, we have ready a release of gllin, the GPS drives. Here is how you can get it:

http://3rdparty.downloads.openmoko.org/gllin/

Instructions, how to use the driver, are given at:

http://lists.openmoko.org/pipermail/community/2007-November/011916.html.

The similar instructions are described in more details at getting GPS console output with gllin.


Unfortunately, gllin expects paths such as /sys/bus/platform/devices/gta01-pm-gps.0/pwron ... and 2.6.24 kernel provides neo1973-pm-gps.0 instead :-(.

-- The following steps seem to be not necessary (anymore?). -- homyx Mar 08, 2008

root@fic-gta01:/media/card/home/root/gllin# cat gllin.real | grep /sys/bus/platform/devices/
/sys/bus/platform/devices/gta01-pm-gps.0/reset
...

root@fic-gta01:/sys/bus/platform/devices# ls -l gta01-pm-gps.0
lrwxrwxrwx    1 root     root            0 Mar  8 11:01 gta01-pm-gps.0 -> ../../../devices/platform/s3c2410-i2c/i2c-adapter/i2c-0/0-0008/neo1973-pm-gps.0
root@fic-gta01:/sys/bus/platform/devices# ls -l neo1973-pm-gps.0
lrwxrwxrwx    1 root     root            0 Mar  8 11:01 neo1973-pm-gps.0 -> ../../../devices/platform/s3c2410-i2c/i2c-adapter/i2c-0/0-0008/neo1973-pm-gps.0
root@fic-gta01:/sys/bus/platform/devices# uname -a
Linux fic-gta01 2.6.24 #1 PREEMPT Wed Mar 5 00:16:31 UTC 2008 armv4tl unknown

Fortunately, you can do evil hack:

cat gllin.real | sed 's-/sys/-/s/s/-g' > gllin.real2
mkdir -p /s/s/bus/platform/devices/
ln -s  /sys/bus/platform/devices/neo1973-pm-gps.0/ /s/s/bus/platform/devices/gta01-pm-gps.0

WARNING:The first step above should not be executed on the phone itself, as BusyBox's sed will corrupt the binary file. It worked for me when run on my host (thanks balrog-kun!)

# gllin.real2 was produced by BusyBox sed
lib/ld-linux.so.2 --library-path /home/root/gllin/lib:/home/root/gllin/usr/lib /home/root/gllin/gllin.real2 -low 5
/home/root/gllin/gllin.real2: error while loading shared libraries: /home/root/gllin/gllin.real2: ELF file version does not match current one

# gllin.real3 was produced by GNU sed version 4.1.5
$ lib/ld-linux.so.2 --library-path /home/root/gllin/lib:/home/root/gllin/usr/lib /home/root/gllin/gllin.real3 -low 5
GPSpwr "1" > /s/s/bus/platform/devices/gta01-pm-gps.0/power_lp_io_3v3
GPSpwr "1" > /s/s/bus/platform/devices/gta01-pm-gps.0/power_lp_io_3v3
...

Contents

gllin options

The /home/root/gllin/gllin file installed by the new (legitimate!) .ipk package is really just a shell script. You can modify the options passed to gllin.real by editing that script. Here are the options:

Usage:

-help                    Help
-board <type>            Defines board type    Ex: '-board matchbox'
                         supported: matchbox, trident
-com <com port>          GPS com port;         Ex: '-com com6'
-baud <baud rate>        Set baud rate;        Ex: '-baud 115200'
-rft <RF type>           Set RF type;          Ex: '-rft RF_LN22OUT'
-freq <freq plan> | ?    set frequency plan for GPS or show the list of all available plans
                         Ex: '-freq FRQ_PLAN_OCXO_10000'
                         Ex: '-freq ?' -- Show all available plans
-g <URL>                 SUPL Server URL or IP address;
                         Ex: '-g 216.15.9.46'
-p <port>                SUPL Server port number;
                         Ex: '-p 9118'
-udp <port>              Local UDP port to send NMEA to.
                         '-udp 6000'      [default]
-gsm_cell <cell ID>      set GSM Cell ID information
                         cell ID has the following format: '<MCC>.<MNC>.<LAC>.<CI>'
                         Where:
                               MCC - Mobile Country Code
                               MNC - Mobile Network Code
                               LAC - Location Area Code
                               CI  - Cell Identification
                         Ex: '-gsm_cell 310.170.367.25732'
-set_assisted_off        disable SET assisted capability
-set_based_off           disable SET based capability
-msisdn <MSISDN>         set value for MSISDN (international phone number) as SET id
                         Ex: '-msisdn 14081234567'
-nai <nai>               specify Network Access Identifier as SET id
                         Ex: '-nai 12345@mywebsite.com'
-periodic <s>            make periodic request every s second (-1 to 64)
                         -1  single shot: perform one fix, then quit
                          0       native: perform fixes as fast as possible
                         <s>       timed: report a position every <s> seconds
                                          where <s> is 1 to 64
-recover                 recover GLLIN after signaled exit
-low [<count>]           low level test.  Default <count> is 1
-low_debug               Low level debug ON
+low_debug               Low level debug OFF
-train <count>           Send train data <count> times
+pty | -pty              Enable or disable NMEA output to pty "/tmp/nmeaPTY"
                         Default is off [-pty]
+np | -np                Enable or disable NMEA output to named pipe "/tmp/nmeaNP"
                         Default is on [-np]
+nmea | -nmea            Enable or disable NMEA output to log file
                         Default is off [-nmea]
+daemon | -daemon        Become a daemon (or not)
                         Default is -daemon
-a2 | -a3 | -a0          Select a GTA01 board revision.  Default is a3
-batch <st> <n> <fix>    perform batch test of <n> starts of type <st>
                         <st> is hot, warm, cold, or SNR.
                         Each start has <fix> fixes.
-i                       start GLLIN command line
+pnd                     optimize for PND
-pnd                     look for low signal strength signals
+sim                     using simulator so don't use almanac
-sim                     not using simulator
SNR                      manufacturing SNR test mode
hot                      hot start [default]
warm                     warm start
cold                     cold start
-v[n]                    Report GLLIN version string.
                         n is 1234 to report selected versions.
 version 1.1.7

Using gpsd with gllin

edit /etc/default/gpsd and set the GPS_DEV to /tmp/nmeaNP start gpsd before gllin.

Some notes:

The listed defaults don't seem to be correct. By default it DOES generate NMEA data in log files. These log files are on your flash (/home/root/gllin/log/*) and are written to once every second. Ridiculous!

To stop this, add the option "-nmea" to the second of the two gllin.real commands in the startup script.

But note further that the startup script also spawns a command to 'cat' the output of the /tmp/nmeaNP named pipe to a gzipped file in /home/root. If you want this to stop, you can do one of two things:

 * cat to /dev/null instead of | gzip >> file
 * add "-np" to the second gllin.real command

You can't just take the 'cat' command out of the script, because with the named pipe activated, gllin will QUIT if it doesn't see anybody taking the output from the pipe. To keep it going, either open that pipe or turn it off.

You can use this gllin initscript to start and stop gllin.

Another option:

#!/bin/sh
echo "Starting gllin..."

killall cat
killall gllin.real

mknod /tmp/nmeaNP p
cat /tmp/nmeaNP > /dev/null &
cd /home/root/gllin
lib/ld-linux.so.2 --library-path /home/root/gllin/lib:/home/root/gllin/usr/lib /home/root/gllin/gllin.real -low 5
lib/ld-linux.so.2 --library-path /home/root/gllin/lib:/home/root/gllin/usr/lib /home/root/gllin/gllin.real -periodic 1 -nmea

More Initscripts

The gllin package doesn't come with a very good set of initscripts, and gpsd is flexible enough to use gllin or some other source of GPS coordinates.

For gpsd and gllin to run together well, upon boot, the following scripts have worked well for me:

/etc/init.d/gpsd:

#!/bin/sh
#
# gpsd	This shell script starts and stops gpsd.
#
# chkconfig: 345 90 40
# description: Gpsd manages access to a serial- or USB-connected GPS
# processname: gpsd

# Source function library.
#. /etc/rc.d/init.d/functions

RETVAL=0
prog="gpsd"

test -f /etc/default/${prog} && . /etc/default/${prog}

start() {
	# Start daemons.
	echo -n "Starting ${prog}: "
	# We don't use the daemon function here because of a known bug
	# in initlog -- it spuriously returns a nonzero status when 
	# starting daemons that fork themselves.  See
	# http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=130629
	# for discussion.  Fortunately:
	#
	# 1. gpsd startup can't fail, or at least not in the absence of
	# much larger resource-exhaustion problems that would be very obvious.
	#
	# 2. We don't need all the logging crud that daemon/initlog sets
	# up -- gpsd does its own syslog calls.
	#
	
	if [ -e "${GPS_DEV}" ]
	then
	    ${prog} -n ${GPSD_OPTS} ${GPS_DEV}
	    RETVAL=$?
	    echo "success"
	else
	    # User needs to symlink ${GPS_DEV} to the right thing
	    # Do it automatically if the name contains "NP"
	    if echo ${GPS_DEV} | grep -q NP
	    then
	        mknod ${GPS_DEV} p
	        ${prog} -n ${GPSD_OPTS} ${GPS_DEV}
	        RETVAL=$?
	        echo "success"
	    else
	        RETVAL=$?
	        echo "No ${GPS_DEV} GPS device, aborting gpsd startup. Check /etc/default/${prog}"
	    fi
	fi
	[ $RETVAL -eq 0 ] && touch /var/lock/subsys/gpsd
	return $RETVAL
}

stop() {
	# Stop daemons.
	echo -n "Shutting down ${prog}: "
        killall ${prog}
	RETVAL=$?
	echo
	if [ $RETVAL -eq 0 ]
	then
	    test -e /var/lock/subsys/gpsd && rm -f /var/lock/subsys/gpsd;
	fi
	return $RETVAL
}

# See how we were called.
case "$1" in
  start)
	start
	;;
  stop)
	stop
	;;
  restart|reload)
	stop
	start
	RETVAL=$?
	;;
  condrestart)
	if [ -f /var/lock/subsys/gpsd ]; then
	    stop
	    start
	    RETVAL=$?
	fi
	;;
  status)
#	status gpsd
#	RETVAL=$?
	;;
  *)
	echo "Usage: $0 {start|stop|restart|condrestart|status}"
	exit 1
esac

exit $RETVAL

/etc/init.d/gllin:

#!/bin/sh
#
# This shell script starts and stops gllin.
#

RETVAL=0
prog="gllin"
GLLIN_PATH=/home/root/gllin

test -f /etc/default/${prog} && . /etc/default/${prog}

start() {
	# Make fifo if it doesn't already exist
	if [ ! -p /tmp/nmeaNP ]
	then
	  mknod /tmp/nmeaNP p
	fi

	# Check for gpsd ready (max 5 seconds)
	echo -n "Waiting for gpsd . . . "
	sleep 1
	if [ ! "$(pidof gpsd)" ]
	then
	  sleep 4
	  if [ ! "$(pidof gpsd)" ]
	  then
	    RETVAL=1
	    echo "failure."
	    return $RETVAL
	  fi
	fi
	
	# Start daemons.
	echo -n "starting ${prog}: "
	cd $GLLIN_PATH
	sleep 1
	if [ -e $GLLIN_PATH/${prog}.real ]
	then
	  $GLLIN_PATH/lib/ld-linux.so.2 --library-path $GLLIN_PATH/lib $GLLIN_PATH/${prog}.real -low 5 > /dev/null
	  $GLLIN_PATH/lib/ld-linux.so.2 --library-path $GLLIN_PATH/lib $GLLIN_PATH/${prog}.real -periodic 1 +daemon
	else
	  $GLLIN_PATH/lib/ld-linux.so.2 --library-path $GLLIN_PATH/lib $GLLIN_PATH/${prog} -low 5 > /dev/null
	  $GLLIN_PATH/lib/ld-linux.so.2 --library-path $GLLIN_PATH/lib $GLLIN_PATH/${prog} -periodic 1 +daemon
	fi
	echo "success."
	RETVAL=$?
	echo
	return $RETVAL
}

stop() {
	# Stop daemons.
	echo -n "Shutting down ${prog}: "
	pkill ld-linux.so.2	
    	RETVAL=$?
	echo "success."
	return $RETVAL
}

# See how we were called.
case "$1" in
  start)
	start
	;;
  stop)
	stop
	;;
  restart|reload)
	stop
	start
	RETVAL=$?
	;;
  status)
#	RETVAL=$?
	;;
  *)
	echo "Usage: $0 {start|stop|restart|condrestart|status}"
	exit 1
esac

exit $RETVAL

These scripts allow you (or init, if you have them numbered in rcX.d appropriately) to start gpsd *before* gllin. This way, gpsd starts listening on /tmp/nmeaNP immediately, and gllin doesn't need to send output to /dev/null in order to stay alive.

This version of the gpsd script will create the named pipe (if the device name includes "NP" in the filename) if it doesn't exist.

Personal tools

gllin is an userpsace driver for a hammerhead GPS chip. It was distributed on phase1 openmokos.

Thanks to a tremendous amount of hard work by many people, we have ready a release of gllin, the GPS drives. Here is how you can get it:

http://3rdparty.downloads.openmoko.org/gllin/

Instructions, how to use the driver, are given at:

http://lists.openmoko.org/pipermail/community/2007-November/011916.html.

The similar instructions are described in more details at getting GPS console output with gllin.


Unfortunately, gllin expects paths such as /sys/bus/platform/devices/gta01-pm-gps.0/pwron ... and 2.6.24 kernel provides neo1973-pm-gps.0 instead :-(.

-- The following steps seem to be not necessary (anymore?). -- homyx Mar 08, 2008

root@fic-gta01:/media/card/home/root/gllin# cat gllin.real | grep /sys/bus/platform/devices/
/sys/bus/platform/devices/gta01-pm-gps.0/reset
...

root@fic-gta01:/sys/bus/platform/devices# ls -l gta01-pm-gps.0
lrwxrwxrwx    1 root     root            0 Mar  8 11:01 gta01-pm-gps.0 -> ../../../devices/platform/s3c2410-i2c/i2c-adapter/i2c-0/0-0008/neo1973-pm-gps.0
root@fic-gta01:/sys/bus/platform/devices# ls -l neo1973-pm-gps.0
lrwxrwxrwx    1 root     root            0 Mar  8 11:01 neo1973-pm-gps.0 -> ../../../devices/platform/s3c2410-i2c/i2c-adapter/i2c-0/0-0008/neo1973-pm-gps.0
root@fic-gta01:/sys/bus/platform/devices# uname -a
Linux fic-gta01 2.6.24 #1 PREEMPT Wed Mar 5 00:16:31 UTC 2008 armv4tl unknown

Fortunately, you can do evil hack:

cat gllin.real | sed 's-/sys/-/s/s/-g' > gllin.real2
mkdir -p /s/s/bus/platform/devices/
ln -s  /sys/bus/platform/devices/neo1973-pm-gps.0/ /s/s/bus/platform/devices/gta01-pm-gps.0

WARNING:The first step above should not be executed on the phone itself, as BusyBox's sed will corrupt the binary file. It worked for me when run on my host (thanks balrog-kun!)

# gllin.real2 was produced by BusyBox sed
lib/ld-linux.so.2 --library-path /home/root/gllin/lib:/home/root/gllin/usr/lib /home/root/gllin/gllin.real2 -low 5
/home/root/gllin/gllin.real2: error while loading shared libraries: /home/root/gllin/gllin.real2: ELF file version does not match current one

# gllin.real3 was produced by GNU sed version 4.1.5
$ lib/ld-linux.so.2 --library-path /home/root/gllin/lib:/home/root/gllin/usr/lib /home/root/gllin/gllin.real3 -low 5
GPSpwr "1" > /s/s/bus/platform/devices/gta01-pm-gps.0/power_lp_io_3v3
GPSpwr "1" > /s/s/bus/platform/devices/gta01-pm-gps.0/power_lp_io_3v3
...

gllin options

The /home/root/gllin/gllin file installed by the new (legitimate!) .ipk package is really just a shell script. You can modify the options passed to gllin.real by editing that script. Here are the options:

Usage:

-help                    Help
-board <type>            Defines board type    Ex: '-board matchbox'
                         supported: matchbox, trident
-com <com port>          GPS com port;         Ex: '-com com6'
-baud <baud rate>        Set baud rate;        Ex: '-baud 115200'
-rft <RF type>           Set RF type;          Ex: '-rft RF_LN22OUT'
-freq <freq plan> | ?    set frequency plan for GPS or show the list of all available plans
                         Ex: '-freq FRQ_PLAN_OCXO_10000'
                         Ex: '-freq ?' -- Show all available plans
-g <URL>                 SUPL Server URL or IP address;
                         Ex: '-g 216.15.9.46'
-p <port>                SUPL Server port number;
                         Ex: '-p 9118'
-udp <port>              Local UDP port to send NMEA to.
                         '-udp 6000'      [default]
-gsm_cell <cell ID>      set GSM Cell ID information
                         cell ID has the following format: '<MCC>.<MNC>.<LAC>.<CI>'
                         Where:
                               MCC - Mobile Country Code
                               MNC - Mobile Network Code
                               LAC - Location Area Code
                               CI  - Cell Identification
                         Ex: '-gsm_cell 310.170.367.25732'
-set_assisted_off        disable SET assisted capability
-set_based_off           disable SET based capability
-msisdn <MSISDN>         set value for MSISDN (international phone number) as SET id
                         Ex: '-msisdn 14081234567'
-nai <nai>               specify Network Access Identifier as SET id
                         Ex: '-nai 12345@mywebsite.com'
-periodic <s>            make periodic request every s second (-1 to 64)
                         -1  single shot: perform one fix, then quit
                          0       native: perform fixes as fast as possible
                         <s>       timed: report a position every <s> seconds
                                          where <s> is 1 to 64
-recover                 recover GLLIN after signaled exit
-low [<count>]           low level test.  Default <count> is 1
-low_debug               Low level debug ON
+low_debug               Low level debug OFF
-train <count>           Send train data <count> times
+pty | -pty              Enable or disable NMEA output to pty "/tmp/nmeaPTY"
                         Default is off [-pty]
+np | -np                Enable or disable NMEA output to named pipe "/tmp/nmeaNP"
                         Default is on [-np]
+nmea | -nmea            Enable or disable NMEA output to log file
                         Default is off [-nmea]
+daemon | -daemon        Become a daemon (or not)
                         Default is -daemon
-a2 | -a3 | -a0          Select a GTA01 board revision.  Default is a3
-batch <st> <n> <fix>    perform batch test of <n> starts of type <st>
                         <st> is hot, warm, cold, or SNR.
                         Each start has <fix> fixes.
-i                       start GLLIN command line
+pnd                     optimize for PND
-pnd                     look for low signal strength signals
+sim                     using simulator so don't use almanac
-sim                     not using simulator
SNR                      manufacturing SNR test mode
hot                      hot start [default]
warm                     warm start
cold                     cold start
-v[n]                    Report GLLIN version string.
                         n is 1234 to report selected versions.
 version 1.1.7

Using gpsd with gllin

edit /etc/default/gpsd and set the GPS_DEV to /tmp/nmeaNP start gpsd before gllin.

Some notes:

The listed defaults don't seem to be correct. By default it DOES generate NMEA data in log files. These log files are on your flash (/home/root/gllin/log/*) and are written to once every second. Ridiculous!

To stop this, add the option "-nmea" to the second of the two gllin.real commands in the startup script.

But note further that the startup script also spawns a command to 'cat' the output of the /tmp/nmeaNP named pipe to a gzipped file in /home/root. If you want this to stop, you can do one of two things:

 * cat to /dev/null instead of | gzip >> file
 * add "-np" to the second gllin.real command

You can't just take the 'cat' command out of the script, because with the named pipe activated, gllin will QUIT if it doesn't see anybody taking the output from the pipe. To keep it going, either open that pipe or turn it off.

You can use this gllin initscript to start and stop gllin.

Another option:

#!/bin/sh
echo "Starting gllin..."

killall cat
killall gllin.real

mknod /tmp/nmeaNP p
cat /tmp/nmeaNP > /dev/null &
cd /home/root/gllin
lib/ld-linux.so.2 --library-path /home/root/gllin/lib:/home/root/gllin/usr/lib /home/root/gllin/gllin.real -low 5
lib/ld-linux.so.2 --library-path /home/root/gllin/lib:/home/root/gllin/usr/lib /home/root/gllin/gllin.real -periodic 1 -nmea

More Initscripts

The gllin package doesn't come with a very good set of initscripts, and gpsd is flexible enough to use gllin or some other source of GPS coordinates.

For gpsd and gllin to run together well, upon boot, the following scripts have worked well for me:

/etc/init.d/gpsd:

#!/bin/sh
#
# gpsd	This shell script starts and stops gpsd.
#
# chkconfig: 345 90 40
# description: Gpsd manages access to a serial- or USB-connected GPS
# processname: gpsd

# Source function library.
#. /etc/rc.d/init.d/functions

RETVAL=0
prog="gpsd"

test -f /etc/default/${prog} && . /etc/default/${prog}

start() {
	# Start daemons.
	echo -n "Starting ${prog}: "
	# We don't use the daemon function here because of a known bug
	# in initlog -- it spuriously returns a nonzero status when 
	# starting daemons that fork themselves.  See
	# http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=130629
	# for discussion.  Fortunately:
	#
	# 1. gpsd startup can't fail, or at least not in the absence of
	# much larger resource-exhaustion problems that would be very obvious.
	#
	# 2. We don't need all the logging crud that daemon/initlog sets
	# up -- gpsd does its own syslog calls.
	#
	
	if [ -e "${GPS_DEV}" ]
	then
	    ${prog} -n ${GPSD_OPTS} ${GPS_DEV}
	    RETVAL=$?
	    echo "success"
	else
	    # User needs to symlink ${GPS_DEV} to the right thing
	    # Do it automatically if the name contains "NP"
	    if echo ${GPS_DEV} | grep -q NP
	    then
	        mknod ${GPS_DEV} p
	        ${prog} -n ${GPSD_OPTS} ${GPS_DEV}
	        RETVAL=$?
	        echo "success"
	    else
	        RETVAL=$?
	        echo "No ${GPS_DEV} GPS device, aborting gpsd startup. Check /etc/default/${prog}"
	    fi
	fi
	[ $RETVAL -eq 0 ] && touch /var/lock/subsys/gpsd
	return $RETVAL
}

stop() {
	# Stop daemons.
	echo -n "Shutting down ${prog}: "
        killall ${prog}
	RETVAL=$?
	echo
	if [ $RETVAL -eq 0 ]
	then
	    test -e /var/lock/subsys/gpsd && rm -f /var/lock/subsys/gpsd;
	fi
	return $RETVAL
}

# See how we were called.
case "$1" in
  start)
	start
	;;
  stop)
	stop
	;;
  restart|reload)
	stop
	start
	RETVAL=$?
	;;
  condrestart)
	if [ -f /var/lock/subsys/gpsd ]; then
	    stop
	    start
	    RETVAL=$?
	fi
	;;
  status)
#	status gpsd
#	RETVAL=$?
	;;
  *)
	echo "Usage: $0 {start|stop|restart|condrestart|status}"
	exit 1
esac

exit $RETVAL

/etc/init.d/gllin:

#!/bin/sh
#
# This shell script starts and stops gllin.
#

RETVAL=0
prog="gllin"
GLLIN_PATH=/home/root/gllin

test -f /etc/default/${prog} && . /etc/default/${prog}

start() {
	# Make fifo if it doesn't already exist
	if [ ! -p /tmp/nmeaNP ]
	then
	  mknod /tmp/nmeaNP p
	fi

	# Check for gpsd ready (max 5 seconds)
	echo -n "Waiting for gpsd . . . "
	sleep 1
	if [ ! "$(pidof gpsd)" ]
	then
	  sleep 4
	  if [ ! "$(pidof gpsd)" ]
	  then
	    RETVAL=1
	    echo "failure."
	    return $RETVAL
	  fi
	fi
	
	# Start daemons.
	echo -n "starting ${prog}: "
	cd $GLLIN_PATH
	sleep 1
	if [ -e $GLLIN_PATH/${prog}.real ]
	then
	  $GLLIN_PATH/lib/ld-linux.so.2 --library-path $GLLIN_PATH/lib $GLLIN_PATH/${prog}.real -low 5 > /dev/null
	  $GLLIN_PATH/lib/ld-linux.so.2 --library-path $GLLIN_PATH/lib $GLLIN_PATH/${prog}.real -periodic 1 +daemon
	else
	  $GLLIN_PATH/lib/ld-linux.so.2 --library-path $GLLIN_PATH/lib $GLLIN_PATH/${prog} -low 5 > /dev/null
	  $GLLIN_PATH/lib/ld-linux.so.2 --library-path $GLLIN_PATH/lib $GLLIN_PATH/${prog} -periodic 1 +daemon
	fi
	echo "success."
	RETVAL=$?
	echo
	return $RETVAL
}

stop() {
	# Stop daemons.
	echo -n "Shutting down ${prog}: "
	pkill ld-linux.so.2	
    	RETVAL=$?
	echo "success."
	return $RETVAL
}

# See how we were called.
case "$1" in
  start)
	start
	;;
  stop)
	stop
	;;
  restart|reload)
	stop
	start
	RETVAL=$?
	;;
  status)
#	RETVAL=$?
	;;
  *)
	echo "Usage: $0 {start|stop|restart|condrestart|status}"
	exit 1
esac

exit $RETVAL

These scripts allow you (or init, if you have them numbered in rcX.d appropriately) to start gpsd *before* gllin. This way, gpsd starts listening on /tmp/nmeaNP immediately, and gllin doesn't need to send output to /dev/null in order to stay alive.

This version of the gpsd script will create the named pipe (if the device name includes "NP" in the filename) if it doesn't exist.