LOOKUPD

Section: Maintenance Commands (8)
Updated: July 21, 1992
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NAME

lookupd - lookup daemon

SYNOPSIS

lookupd [ -i ] | [ [ -f ] [ -m minutes ] ] [ -L | -l filename ]

DESCRIPTION

The lookupd daemon is used in conjunction with NetInfo to speed up various system lookups, such as host entries, user names, and printer names. For performance reasons lookupd caches information about the location of NetInfo domains. It also caches various other information, including groups, user accounts, and mount entries. There are three different types of caches: the user entry cache (also called the pwent cache), the logged-in user and root user cache, and the other caches (hostname, mounts, and printers). By default, the user entry cache is preloaded once, and lookupd then waits until thegetpwent(2) library routine is used before checking whether the cache contents have expired. (This is called lazy cache refresh.) lookupd writes a file with its process ID number (pid file) in /etc/lookupd.pid.

The logged-in user and root user account caches are loaded when a user logs in through loginwindow(8), and are flushed when that user logs out. They are both refreshed every twenty minutes, and when the logged-in user changes his or her password.

Other caches are maintained in a consistent fashion: prior to using the cached information, lookupd checks whether the source NetInfo database has changed. If not, the cached information is used; if so, that cache is refreshed and the new information used.

The lookupd daemon supports the Network Information Service (NIS, formerly called Yellow Pages or YP) and BIND. By default, these features are turned off. NIS can be enabled using the HostManager application, by setting the NIS Domain Name. BIND is enabled by the existence of a /locations/resolver NetInfo directory or an /etc/resolv.conf file. The search policy when these are enabled is to try NetInfo first. If the information is located there, the result is returned. Otherwise, BIND is tried next (for host names and addresses), then NIS. Note that when NIS is consulted, full NIS semantics are implemented, including examining the UNIX flat files, or not, and honoring the presence or absence of the NIS ``+'' magic cookie, depending on the information being requested.

The lookupd daemon will restart itself in response to a hangup signal, SIGHUP. This is useful to tell lookupd that things have changed. For example, if the network gets turned on later, sending a SIGHUP to lookupd will get lookupd to recognize the network and look for information on it.

When lookupd receives a user1 signal, SIGUSR1, it reports its current connections through syslog(5) using the daemon facility at priority info (daemon.info). When lookupd receives a user2 signal, SIGUSR2, it toggles logging. If logging is on, it turns it off. If logging is off, it turns it on. If logging was not configured using either the -L or -l options, the SIGUSR2R signal is ignored.

OPTIONS

-f: Force regularly scheduled updates of the pwent cache (by turning off lazy cache refresh); default is every 30 minutes.
-f -m X: The pwent cache is flushed every X minutes. Note: the value of X cannot be 0 (zero).
-m minutes: Set the lazy refresh interval for the pwent cache to the specified number of minutes. A value of zero turns off pwent caching altogether.
-i: Flushes the pwent cache if it is out-of-date; it will be reloaded the next time it is used. Incompatible with all other options.
-L filename: Asks that all lookup requests be logged to the specified file. Information logged includes the routine called, argument to the routine (an asterisk here denotes a cache hit), total number of calls to the routine, CPU time this call took (in milliseconds), and total CPU time used by this routine (also in milliseconds). Note that the lookupd log can become quite large over time.
-l filename: Configures logging like the -L option, except that logging is initially disabled.

FILES

/etc/lookupd.pid

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Time: 03:03:02 GMT, December 07, 2024