xref: /freebsd/usr.sbin/nscd/nscd.8 (revision 4d846d260e2b9a3d4d0a701462568268cbfe7a5b)
1.\" Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
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25.\" $FreeBSD$
26.\"
27.Dd October 5, 2018
28.Dt NSCD 8
29.Os
30.Sh NAME
31.Nm nscd
32.Nd "name service caching daemon"
33.Sh SYNOPSIS
34.Nm
35.Op Fl dnst
36.Op Fl i Ar cachename
37.Op Fl I Ar cachename
38.Sh DESCRIPTION
39The
40.Nm
41utility
42is the system caching daemon.
43It can cache almost all types of data and is basically intended to be used
44with the
45.Nm nsswitch
46subsystem.
47The cache is actually per-user.
48This means that each user can work only with the
49cached data that were cached by themselves, and cannot poison the
50cache of other users.
51The
52.Nm
53utility supports two types of caching:
54.Bl -tag -width ".Sy Type"
55.It Sy Type
56.Sy Description
57.It Common caching
58Each cached element is the key+value pair.
59This type of caching supports policies which are applied when maximum
60number of cached elements is exceeded.
61Three policies are available:
62.Cm FIFO
63(first in - first out),
64.Cm LRU
65(least recently used) and
66.Cm LFU
67(least frequently used).
68This type of caching is used with the
69.Fn getXXXbyname
70family of functions.
71.It Multipart caching
72Each cached element is the part of the elements sequence.
73This type of caching is intended to be used with the
74.Fn getXXXent
75family of functions.
76.El
77.Pp
78The
79.Nm
80utility is able not only to cache elements, but to perform the actual nsswitch
81lookups by itself.
82To enable this feature, use the
83.Va perform-actual-lookups
84parameter in
85.Xr nscd.conf 5 .
86.Pp
87The
88.Nm
89utility recognizes the following runtime options:
90.Bl -tag -width indent
91.\" .It Fl d
92.\" XXX Document me!
93.It Fl n
94Do not daemonize;
95.Nm
96will not fork or disconnect itself from the terminal.
97.It Fl s
98Single-threaded mode.
99Forces using only one thread for all processing purposes (it overrides
100the
101.Va threads
102parameter in the
103.Xr nscd.conf 5
104file).
105.It Fl t
106Trace mode.
107All trace messages will be written to stdout.
108This mode is usually used with
109.Fl n
110and
111.Fl s
112flags are used for debugging purposes.
113.It Fl i Ar cachename
114Invalidates personal cache.
115When specified,
116.Nm
117acts as the administration tool.
118It asks the already running
119.Nm
120to invalidate the specified part of the cache of the
121calling user.
122For example, sometimes you may want to invalidate your
123.Dq Li hosts
124cache.
125You can specify
126.Dq Li all
127as the
128.Ar cachename
129to invalidate your personal cache as a whole.
130You cannot use this option for the
131.Ar cachename
132for which the
133.Va perform-actual-lookups
134option is enabled.
135.It Fl I Ar cachename
136Invalidates the cache for every user.
137When specified,
138.Nm
139acts as the administration tool.
140It asks the already
141running
142.Nm
143to invalidate the specified part of the cache for
144every user.
145You can specify
146.Dq Li all
147as the
148.Ar cachename
149to invalidate the whole cache.
150Only the root can use this option.
151.El
152.Sh FILES
153.Bl -tag -width ".Pa /etc/nscd.conf" -compact
154.It Pa /etc/nscd.conf
155The default configuration file.
156.El
157.Sh SEE ALSO
158.Xr nsdispatch 3 ,
159.Xr nscd.conf 5 ,
160.Xr nsswitch.conf 5
161.Sh AUTHORS
162.An Michael Bushkov Aq Mt bushman@FreeBSD.org
163