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sfsagent reference guide

sfsagent is the program users run to authenticate themselves to remote file servers, to create symbolic links in /sfs on the fly, and to look for revocation certificates. Many of the features in sfsagent are controlled by the sfskey program and described in the sfskey documentation.

Ordinarily, a user runs sfsagent at the start of a session. sfsagent runs sfskey add to obtain a private key. As the user touches each SFS file server for the first time, the agent authenticates the user to the file server transparently using the private key it has. At the end of the session, the user should run sfskey kill to kill the agent.

The usage is as follows:

sfsagent [-dnkF] -S sock [-c [prog [arg ...]] | keyname]

-d

Stay in the foreground rather than forking and going into the background

-n

Do not attempt to communicate with the SFS file system. This can be useful for debugging, or for running an agent on a machine that is not running an SFS client. If you specify -n, you must also use the -S option, otherwise your agent will be useless as there will be no way to communicate with it.

-k

Atomically kill and replace any existing agent. Otherwise, if your agent is already running, sfsagent will refuse to run again.

-F

Turn off forwarding. By default programs other than the file system can ask the agent to authenticate the user. Specifying this option disables this functionality.

-S sock

Listen for connections from programs like sfskey on the Unix domain socket sock. Ordinarily sfskey connects to the agent through the client file system software, but it can use a named Unix domain socket as well.

-c [prog [arg ...]]

By default, sfsagent on startup runs the command sfskey add giving it whatever -t option and keyname you specified. This allows you to fetch your first key as you start or restart the agent. If you wish to run a different program, you can specify it using -c. You might, for instance, wish to run a shell-script that executes a sfskey add followed by several sfskey certprog commands.

sfsagent runs the program with the environment variable SFS_AGENTSOCK set to -0 and a Unix domain socket on standard input. Thus, when atomically killing and restarting the agent using -k, the commands run by sfsagent talk to the new agent and not the old.

If you don't wish to run any program at all when starting sfsagent, simply supply the -c option with no prog. This will start an new agent that has no private keys.