Here are a couple of daemons useful for netbooting old hardware such as Sun and Silicon Graphics workstations from a modern OS X server. SGI machines generally need bootparamd, and old Sun machines (e.g., SparcStations) need rarpd. To actually boot them you'll need to set up tftp, DHCP/BOOTP and NFS, but those do not need custom daemons (though I recommend dnsmasq).

These programs have only been tested on 10.8 Mountain Lion and 10.9 Mavericks servers so far, but they do work for netbooting an SGI Indy and a Sun SparcStation 5… for me, at least. As always, use at your own risk only.

~ Kimmo Kulovesi, 2013-09-08

bootparamd

Current versions of Mac OS X do not support bootparams anymore, so I ported the FreeBSD bootparamd to OS X. It reads boot parameters from a bootparams file only (i.e., not from OS X netinfo like Apple's bootparamd). The daemon itself works just like the FreeBSD bootparamd does.

Installing bootparamd

To install bootparamd as a system daemon on OS X, follow these steps:

make bootparamd
sudo mkdir -p /usr/local/sbin
sudo cp bootparamd /usr/local/sbin/bootparamd
sudo cp com.arkku.bootparamd.plist /Library/LaunchDaemons/
sudo launchctl load -w /Library/LaunchDaemons/com.arkku.bootparamd.plist

Edit the .plist to configure arguments, and place your boot parameters file as /etc/bootparams (see bootparams(5) for the file format).

An example /etc/bootparams file for netbooting an SGI machine would be:

# SGI Indy
indy    root=server:/exports/indy/root \
        swap=server:/exports/indy/swap

Here indy is the hostname of the machine being booted, server is the hostname of the NFS server, and /exports/indy is a path on the server that is being exported via NFS. The directory root should contain the filesystem for the client, while the directory swap should contain just a file called _swap that is the size of the desired swap. A bootparams entry may specify any number of other parameters as well, the meaning of which depends on the system being booted.

The installation may be tested with the included program callbootd, e.g., ./callbootd 127.0.0.1 indy root should print the root path when run on the server with the above /etc/bootparams. (In my experience the callbootd program is a bit unreliable, so try booting the actual client machine even if the test doesn't work.)

rarpd

Mac OS X does still ship with rarpd, but unfortunately the included daemon effectively needs to be run as root and it only serves requests for hosts that have a bootfile matching their hexadecimal IP address in the /tftpboot directory on the system. So, I took the source code of Apple's rarpd and modified it with the following changes:

• support argument -e to respond to every RARP request, i.e., skip checking for /tftpboot for files named after the IP address of the machine requesting RARP (the original purpose of this check is to allow multiple RARP servers on the same network, each responding only to requests for hosts it has a netboot file for)

• add command-line option -u user to drop root privileges after setting up the daemon (e.g., rarpd -u nobody en0)

• add command-line option -c /directory to chroot to the directory after setting up the daemon - note that the new root must still contain /etc and the files required to resolve the requests, so the intended use is -c /private on OS X where /etc symlinks to /private/etc

• add command-line option -t /directory to specify a tftpboot directory other than the default /tftpboot where to search for netboot files (when -e is not specified), e.g., rarpd -t /private/tftpboot

Installing rarpd

To install rarpd as a system daemon on OS X, follow these steps:

make rarpd
sudo mkdir -p /usr/local/sbin
sudo cp rarpd /usr/local/sbin/rarpd
sudo cp com.arkku.rarpd.plist /Library/LaunchDaemons/
sudo launchctl load -w /Library/LaunchDaemons/com.arkku.rarpd.plist

Edit the .plist to configure arguments. For the daemon to actually serve any requests, create /etc/ethers to specify mappings from ethernet addresses to hostnames, and edit /etc/hosts to map those hostnames to IPv4 addresses.

To test rarpd before installation, I recommend running it in debug mode in a terminal while booting the client machine, e.g., with the command line:

sudo ./rarpd -d -e -c /private -u nobody en0

I added a bunch of debug messages to the program, so this should output all requests and responses. If you intend to run without the argument -e, you can also find out the names of the bootfiles rarpd looks for by looking at the debug messages (in case you are lazy and don't want to convert the client IP addresses to hexadecimal by hand).