bootdirD1135799889Aziphos (207.183.171.11)#In Mid December 2002, a new feature was added to the system. It#changes 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 a#script 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#lists the files to be placed in #//boot. There are no binaries in #/#itself anymore.##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 listed#as /boot. It is now /boot/boot, and no longer a special case.##Now that everything is in /boot, initcode had to change for all the#kernels; /boot/boot itself had to change to exec /boot/ipconfig#(instead of /ipconfig), etc. Finally, auth_getkey changed. It looks#for /factotum and then /boot/factotum, to deal with either type of#kernel.##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. You#could imagine just using the last path element, but that might lead#to weird build inconsistencies if kernels were using two different#files with the same last element. One unfortunate consequence of the#big name is that _386_bin_auth_factotum.root.s is too long for the#current file servers to deal with. You could use lnfs to get around#this, but I didn't want to require lnfs(4) for the kernel build, so#we have a rule in portmkfile that copies factotum and ipconfig to#factotum.hack and ipconfig.hack and then the bootdir section#actually looks 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 namespace#that /boot/boot can be a shell script. Eventually the other#architectures should change too, though it's not urgent. If someone#wants to do the bitsy, send me mail and I'll let you know what it#took 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 other#night. It uses rx and trampoline to connect through a Plan 9 gateway#machine 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#pushes cfs onto the connection.##The point is that bootext is a shell script, which makes it easier#to tweak 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 srvthru#as the way to establish /srv/boot (and also /srv/emelie, just for#kicks).#