sfs_environ(7)

NAME

sfs_environ - SFS environment variables

DESCRIPTION

The following environment variables affect many of SFS's

component programs. (Note that for security reasons, the setuid

programs suidconnect and newaid interpret some of these slightly

differently--ignoring some and dropping privilege if others are

set.)

ACLNT_TRACE

Used mostly for debugging, ACLNT_TRACE causes most SFS

commands to print a trace of all the RPCs they make. The envi

ronment variable must be set to an integer. The higher the val

ue, the more trace information. The value 1 causes only anoma

lous situations such as retransmissions to be reported. 2 causes

every RPC to be printed. 4 causes both RPC calls and replies to

be printed. Arguments over 5 cause the actual RPC argument and

result data structures to be pretty-printed-the higher the number

the greater the depth to which recursive data structures will be

expanded. A value of 10 is generally sufficient to get a very

complete RPC trace.

ACLNT_TIME

A boolean value. When this environment variable and

ACLNT_TRACE are both set, the trace includes timestamps as well,

which can be useful in debugging.

ASRV_TRACE
ASRV_TIME

These perform an analogous function to ACLNT_TRACE and

ACLNT_TIME

than ones made.
BINDADDR

If set, must contain an IPv4 address. Whenever SFS

creates a socket that would be bound to INADDR_ANY, it will be

bound to BINDADDR instead (unless BINDADDR is no longer a valid

local address).

FDLIM_HARD
FDLIM_SOFT

Most of the daemons that comprise SFS use asynchronous

I/O to handle multiple network connections concurrently. In or

der to be able to handle as many concurrent connections as possi

ble, the library raises the per-process file descriptor limit to

the maximum allowable value. For privileged processes, this ad

ditionally means raising the so-called ``hard'' file descriptor

limit. When raising these values, if the FDLIM_SOFT and

FDLIM_HARD

old limit values in the environment variables.
An example of how this is used is by rexd, the remote

execution daemon. rexd reduces the file descriptor limits to the

original values specified by these environment variables before

spawning an unprivileged user program. These variables ordinari

ly should not be of concern to users of SFS, and are documented

here mostly for people who notice them and are curious.

SFS_AGENTSOCK

Ordinarily sfskey connects to sfsagent through the SFS

client daemon, sfscd. However, by passing the -S option to

sfsagent, it is possible to have sfsagent bind an arbitrary Unix

domain socket for connections. SFS_AGENTSOCK can be set to such

a pathname, and sfskey will then connect to that socket.

As a special case, if SFS_AGENTSOCK is set to a nega

tive number, this is interpreted to mean a file descriptor number

already connected to the agent. This feature is particularly

useful when atomically killing and starting sfsagent with the -k

flag. In this case, and program specified on the command line,

or the default /usr/local/share/sfs/agentrc script, will be run

with SFS_AGENTSOCK set to a file descriptor. Thus, if the script

loads keys into the agent by running sfskey, these keys will be

loaded into the new agent (before it takes over), rather than in

to the old agent.

SFS_CONFIG

The location in which to find the sfs_config file. By

default, SFS uses configuration files in

/usr/local/share/sfs/sfs_config and /etc/sfs/sfs_config. sfssd

sets this environment variable when given the -S option, so that

subsidiary daemons read the same configuration file.

SFS_HOSTNAME

Overrides SFS's default algorithm for figuring out the

local hostname. Several SFS programs must know the machine's

fully-qualified hostname. In particular, this name constitutes

the official Location in a server's self-certifying pathname

(since a given file system should have only one self-certifying

hostname). The hostname of an SFS server must exist in the DNS

(as opposed to just /etc/hosts) for many of the servers to work.

The algorithm used by SFS is to determine a host's

name is as follows. It checks the system's name with the

gethostname system call, and if it is fully-qualified (i.e., has

a ``.domain'' at the end) uses that. Otherwise, it appends the

default domain name to the system name.

Sometimes SFS's algorithm will not produce the correct

hostname. In that case, you can specify the real hostname for

each individual daemon such as sfsrwsd and sfsauthd in their con

firuation files. Or, you can just set the environment variable

SFS_HOSTNAME

a DNS name, you can also set SFS_HOSTNAME to the numeric IPv4 address of your host, and then use the IP address as the Location in self-certifying pathnames.
SFS_PORT

This variable, if set, specifies official port number

of an SFS server--i.e. the %port that clients must append to the

hostname in the Location of the self-certifying pathname. By de

fault (or if SFS_PORT is set to 0), the self-ceritying pathname

contains no port number, which means to check DNS for SRV

records, and if none are found to use port 4.

Because servers have only one canonical self-certify

ing pathname, setting SFS_PORT to 4 is not the same thing as set

ting it to 0, even without SRV records. If you set SFS_PORT to

4, then clients who do not specify %4 in the self-certifying

pathname will need to be redirected to a pathname containing %4

via a symbolic link, and pwd run on a client will show the %4 as

part of the self-certifying pathname.

Note further that the effects of this environment

variable should not be confused with the BindAddr option in

sfssd_config. For example, if you set up SRV records pointing to

TCP port 5 on your server, you might want to specify BindAddr

0.0.0.0 5 in sfssd_config, but you almost certainly would not

want to set the SFS_PORT environment variable to 5, as setting

SFS_PORT

name contains %5, which in turn means DNS SRV records should not
be used. (I.e., a client accessing @host.domain,hostid would be redirected to @host.domain%5,hostid, which would bypass any SRV records for host.domain and, depending on DNS data, might not even resolve to the same IP address as the pathname without a %.)
SFS_ROOT

Sets the root directory of the SFS file system, which

is usually /sfs. Changing this for anything other than debugging

purposes is not recommended, as many symbolic links will break.

SFS_RUNINPLACE

SFS consists of a large number of interacting daemons.

Ordinarily, these are launched by sfscd and sfssd. If you wish

to run SFS without installing it, however, these commands will

not be able to find the subsidiary daemons they are supposed to

launch. Setting SFS_RUNINPLACE to the root of your build direc

tory allows SFS to be run without installing it. Because this

option is mainly used for development, however, several programs

behave slightly differently when it is set. sfscd and sfssd both

remain in the forground and send their output to standard error,

rather than to the system log. Moreover, sfsagent does take

steps to protect itself from the ptrace system call, so that you

can attach to it with the debugger when running in place.

TMPDIR

Some SFS programs need to create temporary files or

Unix-domain sockets in the local file system. By default, these

programs use the /tmp directory or created protected subdirecto

ries of /tmp. However, you can override the location by setting

the TMPDIR environment variable.

USER

In various places SFS needs a default username--for

example, when running sfskey login. SFS looks first at the USER

environment variable, then uses the getlogin system call, and if

that fails, looks up the current user ID in the system password

file.

SEE ALSO

dirsearch(1), newaid(1), rex(1), sfsagent(1), sfskey(1),

ssu(1), sfs_config(5), sfs_hosts(5), sfs_srp_params(5),

sfs_users(5), sfsauthd_config(5), sfscd_config(5),

sfsrosd_config(5), sfsrwsd_config(5), sfssd_config(5),

funmount(8), nfsmounter(8), sfsauthd(8), sfscd(8), sfsrosd(8),

sfsrwcd(8), sfsrwsd(8), sfssd(8), vidb(8)

The full documentation for SFS is maintained as a Texinfo

manual. If the info and SFS programs are properly installed at

your site, the command info SFS should give you access to the

complete manual.

For updates, documentation, and software distribution,

please see the SFS website at http://www.fs.net/.

AUTHOR

sfsdev@redlab.lcs.mit.edu

SFS 0.8pre 2006-07-20

SFS_ENVIRON(7)