<html><head><title>bootdir (Editing Wed Dec 28 14:58:09 EST 2005 version)</title><META http-equiv="Content-Type" content="text/html; charset=utf-8"></head><!-- FFFFE9 is acme yellow; FFFFE9 is as close as you can get to it before charon decides to use  grey instead of map entry 254 --><body bgcolor="#FFFFE9" link="#0000AA" alink="#0000AA" vlink="#0000AA"><center><font size=+2><b>bootdir</b></font> (Editing Wed Dec 28 14:58:09 EST 2005 version)</center><p> For information on editing, see thedescription of <a href="../0">Plan 9 wiki syntax</a>.<p><form action="/magic/wikipost" method="post"><table><tr><td valign=top><input type="submit" name="x" value="Put"></td><td><table><tr><td align=right>(optional) Comment:</td><td><input type="text" name="comment" value="" cols=40></td></tr><tr><td align=right>(optional) Email:</td><td><input type="text" name="author" value="" cols=40></td></tr></table><input type="hidden" name="title" value="bootdir"><input type="hidden" name="version" value="1135799889"><input type="hidden" name="service" value="plan9"><input type="hidden" name="base" value="/wiki/plan9"><p><textarea name="text" wrap="virtual" cols="80" rows="25">In Mid December 2002, a new feature was added to the system. Itchanges the previous #//boot to be a directory rather than a file,and allows what used to be a binary that had to be compiled to be ascript instead. Russ Cox said something like this in[http://groups.google.com/groups?dq=&hl=en&lr=&ie=UTF-8&selm=606456fcdc17ce997666a1895d86f9ba%40plan9.bell-labs.com] There is a new kernel config file section called "bootdir" that liststhe files to be placed in #//boot. There are no binaries in #/ itselfanymore. A typical bootdir section might look like ! 	bootdir! 		bootpcdisk.out boot! 		/386/bin/ip/ipconfig! 		/386/bin/auth/factotum! 		/386/bin/disk/kfs! 		/386/bin/cfs which says that /boot will contain four files: boot, ipconfig,factotum, kfs, and cfs, copied from the listed paths. The kernels have always special cased boot$CONF.out to get it listedas /boot. It is now /boot/boot, and no longer a special case. Now that everything is in /boot, initcode had to change for all thekernels; /boot/boot itself had to change to exec /boot/ipconfig(instead of /ipconfig), etc. Finally, auth_getkey changed. It looksfor /factotum and then /boot/factotum, to deal with either type ofkernel. The boot file /386/bin/ip/ipconfig (e.g.) turns into_386_bin_ip_ipconfig.root.s and then _386_bin_ip_ipconfig.root.8.It's a bit of an ugly name, but mk clean will get rid of them. Youcould imagine just using the last path element, but that might leadto weird build inconsistencies if kernels were using two differentfiles with the same last element. One unfortunate consequence of thebig name is that _386_bin_auth_factotum.root.s is too long for thecurrent file servers to deal with. You could use lnfs to get aroundthis, but I didn't want to require lnfs(4) for the kernel build, sowe have a rule in portmkfile that copies factotum and ipconfig tofactotum.hack and ipconfig.hack and then the bootdir section actuallylooks like: ! 	bootdir! 		bootpcdisk.out boot! 		ipconfig.hack ipconfig! 		factotum.hack factotum! 		/386/bin/disk/kfs! 		/386/bin/cfs sadly. That will go away when we get long file names. The pc initcode is also changed. Whereas before it used to do ! 	exec("/boot", ["boot", 0]); in hand-coded assembly (pc/initcode.s), it now does ! 	open("#c/cons", OREAD);! 	open("#c/cons", OWRITE);! 	open("#c/cons", OWRITE);! 	bind("#c", "/dev", MAFTER);! 	bind("#ec", "/env", MAFTER);! 	bind("#e", "/env", MCREATE|MAFTER);! 	bind("#s", "/srv", MREPL|MCREATE);! 	execl("/boot/boot", "/boot/boot", 0); in C (port/initcode.c). The point is to set up enough of a namespacethat /boot/boot can be a shell script. Eventually the otherarchitectures should change too, though it's not urgent. If someonewants to do the bitsy, send me mail and I'll let you know what ittook to get one of the old undistributed mips kernels changed over.(The compiler setup is similar.) As a much bigger example, I built a kernel called pcext the othernight. It uses rx and trampoline to connect through a Plan 9 gatewaymachine to the root file server. It uses this bootdir: ! 	bootdir! 		bootext boot! 		/386/bin/rc! 		/rc/lib/rcmain! 		/386/bin/bind! 		/386/bin/cat! 		/386/bin/cp! 		/386/bin/echo! 		/386/bin/mount! 		/386/bin/sleep! 		factotum.hack factotum! 		/386/bin/ip/ipconfig! 		/386/bin/cfs! 		/386/bin/aux/srvthru (and does require lnfs to build). Srvthru is the obvious program -- it connects to rx, authenticates,starts trampoline to the real file server, and then optionally pushescfs onto the connection. The point is that bootext is a shell script, which makes it easier totweak than when /boot was a binary building out of /sys/src/9/boot. ! 	#!/boot/rc -m /boot/rcmain! 	! 	cd /boot! 	cp '#r/rtc' '#c/time'! 	bind -a /boot /bin! 	bind -a '#I' /net! 	bind -a '#l0' /net! 	bind -a '#S' /dev! 	bind '#p' /proc! 	bind '#d' /fd! 	bind -a /boot /! 	ipconfig! 	echo 'authdom=cs.bell-labs.com auth=204.178.31.3' >>/net/ndb! 	factotum -sfactotum -u -a 204.178.31.3! 	cargs=()! 	if(~ $#cfs 1 && ! ~ $cfs off)! 		cargs=(-c $cfs)! 	srvthru $cargs tcp!204.178.31.2!17009 il!emelie!9fs boot emelie! 	mount -c /srv/boot /root! 	bind -ac /root /! 	bind -c /root/mnt /mnt! 	mount -a '#s/factotum' /mnt! 	rootdir=/root! 	rootspec=''! 	/386/init -t! 	/boot/rc -m/boot/rcmain -i	# in case init fails It takes care of everything /boot traditionally does, using srvthruas the way to establish /srv/boot (and also /srv/emelie, just forkicks). </textarea><p></td></table></form> <hr><table width=100%><tr><td valign=center align=left></td><td valign=center align=right><a href="../about.html">About the server</a>| <a href="http://plan9.bell-labs.com/plan9"><img src="http://plan9.bell-labs.com/plan9/img/power36.gif"alt="Powered by Plan 9"></a></td></tr></table></html></body>