lp.rc

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

#!/bin/rc
# lp - enqueues the file to be printed and starts the daemon, when necessary.
# Make changes to /sys/src/cmd/lp/lp.rc;
# changes made directly to /rc/bin/lp will be lost.

rfork en	# so that environment and name space are not polluted
# 
# put 'fn sigexit { rm /tmp/lpcrap; exit interrupted }' into processes that create /tmp/lpcrap.

ifs=' 	
'		# set ifs in case it is munged in user's environment

LPLIB=/sys/lib/lp		# lp scripts directories and configuration file are here
LPBIN=/$cputype/bin/aux		# lp specific binaries are here
LPSPOOL=$LPLIB/queue		# lp queues
LPLOGDIR=$LPLIB/log		# lp logs

$LPLIB/bin/lpscratch
x=$status
if(! ~ $x '') exit $x

# build /bin from the ground up
bind /$cputype/bin /bin			# general compiled binaries
bind -a /rc/bin /bin			# general rc scripts
# This needs to be fixed for the real thing
bind -a $LPLIB/bin /bin			# lp specific rc scripts
bind -a $LPBIN /bin				# lp specific compiled binaries
path=(/bin)

if (! test -w /tmp) bind -bc $LPLIB/tmp /tmp

USAGE='usage:	lp [-d printer] [-p process] [options] [files]
		lp [-d printer] -q
		lp [-d printer] -k jobnos

		options include:
		-D			turn on debugging output
		-H			no header
		-L			landscape mode
		-M<mach>	print on machine <mach>
		-Q			put task only into the queue
		-R			restart printer daemon
		-c<n>		make <n> copies
		-f<font.size>	specify font and size
		-i<src>		take media from <src> input bin
		-l<n>		print <n> lines per logical page
		-m<n>		magnify <n> times
		-n<n>		print <n> logical pages per physical page
		-o<i-j,k>	print only pages i-j and k
		-r			reverse pages
		-u<userid>	print as <userid>
		-x<n>		x page offset in inches
		-y<n>		y page offset in inches
'

# umask 000	# this doesn't work in plan 9
if (~ $#sysname 0)
	THIS_HOST=plan9
if not {
	THIS_HOST=`{ndb/query sys $sysname dom}
	if(~ $#THIS_HOST 0)
		THIS_HOST=$sysname
}

LPMACHID=$THIS_HOST
THIS_USERID=$user
LPUSERID=$THIS_USERID
LPLOC=''

# Set default printer to be output device
if (~ $#LPDEST 0 && test -f $LPLIB/defdevice) LPDEST=`{cat $LPLIB/defdevice}

# option parameters
COPIES=1
FONT=''
IBIN=''
KILLFLAG=0
LAND=''
LINES=''
LPQ=0
MAG=''
NOHEAD=''
NPAG=''
OLIST=''
POINT=''
RESET=''
REVERSE=''
QONLY=''
TRAY=''
XOFF=''
YOFF=''

# Process options
flagfmt='D,H,L,Q,R,r,q,M mach,c copies,d printer,f font.size,i src,k jobnos,l lines,m magnify,n lpages,o pages,p proc,u userid,x offset,y offset'
argv0=lp

if(! ifs=() eval `{aux/getflags $*}) {
	echo $USAGE
	exit usage
}
if(~ $flagd '?'){
	awk 'BEGIN {print "device       location  host                   class"}
/^[^#]/	{ printf "%-12s %-9s %-22s %s\n", $1, $2, $3, $6 }' $LPLIB/devices
	exit
}
if(~ $flagp '?'){
	ls $LPLIB/process
	exit
}

if (! ~ $#flagD 0) { DEBUG=1; flag x + }; if not { DEBUG=''; flag x - }
if (! ~ $#flagH 0) NOHEAD=1
if (! ~ $#flagL 0) LAND=1
if (! ~ $#flagM 0 && ~ $LPUSERID daemon) LPMACHID=$flagM
if (! ~ $#flagQ 0) QONLY=1
if (! ~ $#flagR 0) RESET=1
if (! ~ $#flagc 0) COPIES=$flagc
if(! ~ $#flagd 0) LPDEST=$flagd
if (! ~ $#flagf 0) eval `{echo $flagf | sed -e 's/([^.]*)\.([0-9.]*)/FONT=\1;POINT=\2;/'}
if (! ~ $#flagi 0) IBIN=$flagi
if (! ~ $#flagk 0) KILLFLAG=1
if (! ~ $#flagl 0) LINES=$flagl
if (! ~ $#flagm 0) MAG=$flagm
if (! ~ $#flagn 0) NPAG=$flagn
if (! ~ $#flago 0) OLIST=-o^$flago
if (! ~ $#flagp 0) LPPROC=$flagp
if (! ~ $#flagq 0) LPQ=1
if (! ~ $#flagr 0) REVERSE=1
if (! ~ $#flagu 0) LPUSERID=$flagu
if (! ~ $#flagx 0) XOFF=$flagx
if (! ~ $#flagy 0) YOFF=$flagy

if (~ $#LPDEST 0) {
	echo 'Set environment variable LPDEST or use the
''-d printer'' option to set the destination.' >[1=2]
	exit 'LPDEST not set'
}
if (~ $LPDEST */*) {	# handles MHCC destinations like mh/lino
	LPLOC=`{echo $LPDEST|sed 's/^(.*)\/(.*)/\1/'}
	LPDEST=`{echo $LPDEST|sed 's/^(.*)\/(.*)/\2/'}
}

# look up device, get info
LPDLINE=`{grep '^'$LPDEST'[ 	]' $LPLIB/devices}
if (! ~ $status '') {
	echo 'device '$LPDEST' is not in '$LPLIB'/devices' >[1=2]
	exit 'LPDEST is bad'
}
LOC=$LPDLINE(2)
DEST_HOST=$LPDLINE(3)
OUTDEV=$LPDLINE(4)
SPEED=$LPDLINE(5)
LPCLASS=$LPDLINE(6)
if (~ $#LPPROC 0) LPPROC=$LPDLINE(7)
SPOOLER=$LPDLINE(8)
STAT=$LPDLINE(9)
KILL=$LPDLINE(10)
DAEMON=$LPDLINE(11)
SCHED=$LPDLINE(12)
if (~ $#SCHED 0) SCHED=FIFO	# everyone uses FIFO
if (~ $KILLFLAG 1)
	switch ($KILL) {
	case -;	echo kill option not available on $LPDEST >[1=2]
		exit 'kill n/a'
	case *;	bind -b $LPLIB/kill /bin
		exec $KILL $*
		exit 'kill command '"$KILL"' not found'
	}
if (~ $LPQ 1)
	switch ($STAT) {
	case -;	echo queue status option not available on $LPDEST >[1=2]
		exit 'stat option not available'
	case *;	bind -b $LPLIB/stat /bin
		exec $STAT $* < /dev/null
		exit 'stat command '"$STAT"' not found'
	}
DATE=`{date}
LPLOG=$LPLOGDIR/$LPDEST
if (! test -e $LPLOG) {
	>$LPLOG
	chmod +rwa $LPLOG >[2]/dev/null
}

if (~ $RESET '') {
	switch ($SPOOLER) {
	case -;	echo spooler does not exist for $LPDEST >[1=2]
		exit 'no spooler'
	case *;	bind -b $LPLIB/spooler /bin
		if (~ $#* 0) $SPOOLER
		if not $SPOOLER $*
	}
}
if not {
	echo restarting daemon for printer $LPDEST >[1=2]
	UNLOCK $LPSPOOL/$LPDEST
	sleep 5
}

# run daemon
if (~ $QONLY '') {
	if (! ~ $DAEMON -) {
		bind -b $LPLIB/daemon /bin
		$DAEMON $* >>$LPLOG >[2=1] &
	}
}
exit ''