Provided by: sfs-common_0.8-0+pre20060720.1-1.1_i386
sfs_environ - SFS environment variables
The following environment variables affect many of SFS’s component pro‐
grams. (Note that for security reasons, the setuid programs suidcon
nect and newaid interpret some of these slightly differently--ignoring
some and dropping privilege if others are set.)
Used mostly for debugging, ACLNT_TRACE causes most SFS commands to
print a trace of all the RPCs they make. The environment variable
must be set to an integer. The higher the value, the more trace
information. The value 1 causes only anomalous 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 gen‐
erally sufficient to get a very complete RPC trace.
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.
These perform an analogous function to ACLNT_TRACE and ACLNT_TIME,
but print out RPCs received (as a server), rather than ones made.
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
Most of the daemons that comprise SFS use asynchronous I/O to han‐
dle multiple network connections concurrently. In order to be able
to handle as many concurrent connections as possible, the library
raises the per-process file descriptor limit to the maximum allow‐
able value. For privileged processes, this additionally means
raising the so-called ‘‘hard’’ file descriptor limit. When raising
these values, if the FDLIM_SOFT and FDLIM_HARD environment vari‐
ables are not set, SFS saves their the old limit values in the
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 ordinarily should not
be of concern to users of SFS, and are documented here mostly for
people who notice them and are curious.
Ordinarily sfskey connects to sfsagent through the SFS client dae‐
mon, 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 negative number,
this is interpreted to mean a file descriptor number already con‐
nected 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 into the old agent.
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 con‐
Overrides SFS’s default algorithm for figuring out the local host‐
name. Several SFS programs must know the machine’s fully-qualified
hostname. In particular, this name constitutes the official Loca‐
tion in a server’s self-certifying pathname (since a given file
system should have only one self-certifying hostname). The host‐
name 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 fol‐
lows. 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 confiruation files.
Or, you can just set the environment variable SFS_HOSTNAME before
running sfssd. Note that if you do not have 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 path‐
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 default (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-certifying pathname,
setting SFS_PORT to 4 is not the same thing as setting 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
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_con‐
fig, but you almost certainly would not want to set the SFS_PORT
environment variable to 5, as setting SFS_PORT to anything other
than 0 means the self-certifying pathname 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 %.)
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 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 directory 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.
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 subdirectories of /tmp.
However, you can override the location by setting the TMPDIR envi‐
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.
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_con‐
fig(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 com‐
mand 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/.