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Diffstat (limited to 'man/man5/nss.5')
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diff --git a/man/man5/nss.5 b/man/man5/nss.5 new file mode 100644 index 0000000..258cc11 --- /dev/null +++ b/man/man5/nss.5 @@ -0,0 +1,101 @@ +.\" Copyright (C) 2006 Red Hat, Inc. All rights reserved. +.\" Author: Ulrich Drepper <drepper@redhat.com> +.\" +.\" SPDX-License-Identifier: GPL-2.0-only +.\" +.TH nss 5 2024-05-02 "Linux man-pages (unreleased)" +.SH NAME +nss \- Name Service Switch configuration file +.SH DESCRIPTION +Each call to a function which retrieves data from a system database +like the password or group database is handled by the Name Service +Switch implementation in the GNU C library. +The various services +provided are implemented by independent modules, each of which +naturally varies widely from the other. +.P +The default implementations coming with the GNU C library are by +default conservative and do not use unsafe data. +This might be very costly in some situations, especially when the databases +are large. +Some modules allow the system administrator to request +taking shortcuts if these are known to be safe. +It is then the system administrator's responsibility to ensure the assumption +is correct. +.P +There are other modules where the implementation changed over time. +If an implementation used to sacrifice speed for memory consumption, +it might create problems if the preference is switched. +.P +The +.I /etc/default/nss +file contains a number of variable assignments. +Each variable controls the behavior of one or more +NSS modules. +White spaces are ignored. +Lines beginning with \[aq]#\[aq] +are treated as comments. +.P +The variables currently recognized are: +.TP +\fBNETID_AUTHORITATIVE =\fR \fITRUE\fR|\fIFALSE\fR +If set to TRUE, the NIS backend for the +.BR initgroups (3) +function will accept the information +from the +.I netid.byname +NIS map as authoritative. +This can speed up the function significantly if the +.I group.byname +map is large. +The content of the +.I netid.byname +map is used \fBas is\fR. +The system administrator has to make sure it is correctly generated. +.TP +\fBSERVICES_AUTHORITATIVE =\fR \fITRUE\fR|\fIFALSE\fR +If set to TRUE, the NIS backend for the +.BR getservbyname (3) +and +.BR getservbyname_r (3) +functions will assume that the +.I services.byservicename +NIS map exists and is authoritative, particularly +that it contains both keys with /proto and without /proto for both +primary service names and service aliases. +The system administrator has to make sure it is correctly generated. +.TP +\fBSETENT_BATCH_READ =\fR \fITRUE\fR|\fIFALSE\fR +If set to TRUE, the NIS backend for the +.BR setpwent (3) +and +.BR setgrent (3) +functions will read the entire database at once and then +hand out the requests one by one from memory with every corresponding +.BR getpwent (3) +or +.BR getgrent (3) +call respectively. +Otherwise, each +.BR getpwent (3) +or +.BR getgrent (3) +call might result in a network communication with the server to get +the next entry. +.SH FILES +\fI/etc/default/nss\fR +.SH EXAMPLES +The default configuration corresponds to the following configuration file: +.P +.in +4n +.EX +NETID_AUTHORITATIVE=FALSE +SERVICES_AUTHORITATIVE=FALSE +SETENT_BATCH_READ=FALSE +.EE +.in +.\" .SH AUTHOR +.\" Ulrich Drepper <drepper@redhat.com> +.\" +.SH SEE ALSO +\fInsswitch.conf\fR |