vidb(8)

NAME

vidb - manually edit SFS user-authentication database file

SYNOPSIS

vidb  [-w]  [-R]  {-S  |  -a  [-f  file]  |  [-e  editor]}
sfs-users-file

DESCRIPTION

vidb manually edits an SFS user-authentication file , ac

quiring locks to prevent concurrent updates from overwriting each

other. If sfsauthd has been compiled with Sleepycat database

(http://www.sleepycat.com/) support, and the name of the file

ends in .db/, vidb will consider the user authentication file to

be a database directory, and convert the contents into regular

ASCII text for editing. If the name of the file ends in .db,

vidb assumes the user authentication file is database file (un

less the pathname corresponds to an existing directory). Note

that database files (as opposed to directories) are required to

be read-only, and thus cannot be updated by vidb.

OPTIONS

vidb has the following options:

-a [-f file]

The -a option adds SFS user records in text form to a

database. The records are taken from standard input, or from

file if specified. Records for an existing user or group will

replace the values already in the database. Unlike vidb's ordi

nary mode of operation, -a does not add all records atomically.

In the event of a system crash, some but not all of the records

may have been added to the database. Simply re-running the same

vidb command after a crash is perfectly safe, however, since pre

viously added entries will just be overwritten (by themselves)

the second time through. For database files, because -a does not

accumulate records into one large transaction, it can be signifi

cantly more efficient than simply adding the records in an edi

tor, using vidb's ordinary mode of operation.

-e editor

Specifies the editor to use for editing the file. The

default is to use the command specified by the environment vari

able EDITOR. If there is no environment variable and -e is not

specified, vidb uses vi.

-w One of the points of vidb is to avoid concurrent edits

to the database and the corresponding inconsistencies that might

result. Ordinarily, if the database is already being edited,

vidb will just exit with an error message. The -w flag tells

vidb to wait until it can acquire the lock on the database before

launching the editor.

-R Runs catastrophic recovery on the database environ

ment. (For those familiar with Sleepycat database software, this

corresponds to the -c flag of the db_recover utility, or the

DB_RECOVER_FATAL

of the database log records present in the supporting files directory. You may need to use this, for example, when restoring a
database from backup tapes if the log files were backed up more
recently than the entire database. The -R has no effect on flat
text databases, or if the -S has been specified. Warning: The authors have encountered bugs in the catastrophic recovery code
of at least some versions of the Sleepycat database package. As
a precaution, before attempting to use -R, we strongly recommend
salvaging whatever records possible from the database file itself
using vidb -S sfs-users-file>saved_sfs_users. If, subsequently, the -R option corrupts the database, you can at least salvage
some of the records from the saved_sfs_users file. -S Attempt to salvage a database file with corrupt or

lost logs by dumping the contents of the database itself. Ordi

narily, databases use write-ahead logging. Before opening a

database file, both vidb and sfsauthd attempt to recover from any

previous incomplete transactions using the log. The -S option

opens and prints out the contents of a database without regard to

the log files. This is useful if you have lost the log files or

are worried that they are corrupt, or if you wish to examine the

contents of a database you have read but not write permission to.

Ordinarily, however, if you wish to dump the contents of a

database to standard output, use the command vidb -e cat

sfs-users-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),

sfs_environ(7), funmount(8), nfsmounter(8), sfsauthd(8),

sfscd(8), sfsrosd(8), sfsrwcd(8), sfsrwsd(8), sfssd(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/.

BUGS

vidb should really recreate any publicly-readable versions

of user authentication databases (either by parsing

sfsauthd_config for -pub=... options to Userfile directives or

signaling sfsauthd). Currently you must manually kill sfssd or

sfsauthd for this to happen.

While vidb attempts to make the smallest number of changes

to a database, editing sessions that add or remove a large number

of records can potentially exhaust resources such as locks.

Sites with large user databases can tune the database by creating

a file called DB_CONFIG in the database directory. The specifics

of the configuration file are documented in the Sleepycat

database documentation. As an example, if performance is slow

and you run out of locks, you can set the cache size to 128MB and

increase the number of locks with the following DB_CONFIG file:

set_cachesize 0 134217728 1
set_lk_max_locks 50000
set_lk_max_objects 50000

When editing a database, vidb creates a temporary text

file in the /tmp directory. For huge databases, it is conceiv

able that /tmp does not have enough space. If this happens, /tmp

can be overridden with the TMPDIR environment variable.

AUTHOR

sfsdev@redlab.lcs.mit.edu

SFS 0.8pre 2006-07-20

VIDB(8)