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Diffstat (limited to 'lib/libc/net/nsdispatch.3')
| -rw-r--r-- | lib/libc/net/nsdispatch.3 | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/lib/libc/net/nsdispatch.3 b/lib/libc/net/nsdispatch.3 new file mode 100644 index 0000000..d1d8d5a --- /dev/null +++ b/lib/libc/net/nsdispatch.3 @@ -0,0 +1,259 @@ +.\" $NetBSD: nsdispatch.3,v 1.8 1999/03/22 19:44:53 garbled Exp $ +.\" +.\" Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc. +.\" All rights reserved. +.\" +.\" This code is derived from software contributed to The NetBSD Foundation +.\" by Luke Mewburn. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 4. Neither the name of The NetBSD Foundation nor the names of its +.\" contributors may be used to endorse or promote products derived +.\" from this software without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS +.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED +.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS +.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +.\" POSSIBILITY OF SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd April 4, 2010 +.Dt NSDISPATCH 3 +.Os +.Sh NAME +.Nm nsdispatch +.Nd name-service switch dispatcher routine +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In sys/types.h +.In stdarg.h +.In nsswitch.h +.Ft int +.Fo nsdispatch +.Fa "void *retval" +.Fa "const ns_dtab dtab[]" +.Fa "const char *database" +.Fa "const char *method_name" +.Fa "const ns_src defaults[]" +.Fa "..." +.Fc +.Sh DESCRIPTION +The +.Fn nsdispatch +function invokes the methods specified in +.Va dtab +in the order given by +.Xr nsswitch.conf 5 +for the database +.Va database +until a successful entry is found. +.Pp +.Va retval +is passed to each method to modify as necessary, to pass back results to +the caller of +.Fn nsdispatch . +.Pp +Each method has the function signature described by the typedef: +.Pp +.Ft typedef int +.Fn \*(lp*nss_method\*(rp "void *retval" "void *mdata" "va_list *ap" ; +.Pp +.Va dtab +is an array of +.Va ns_dtab +structures, which have the following format: +.Bd -literal -offset indent +typedef struct _ns_dtab { + const char *src; + nss_method method; + void *mdata; +} ns_dtab; +.Ed +.Bd -ragged -offset indent +The +.Fa dtab +array should consist of one entry for each source type that is +implemented, with +.Va src +as the name of the source, +.Va method +as a function which handles that source, and +.Va mdata +as a handle on arbitrary data to be passed to the method. +The last entry in +.Va dtab +should contain +.Dv NULL +values for +.Va src , +.Va method , +and +.Va mdata . +.Ed +.Pp +Additionally, methods may be implemented in NSS modules, in +which case they are selected using the +.Fa database +and +.Fa method_name +arguments along with the configured source. +(The methods supplied via +.Fa dtab +take priority over those implemented in NSS modules in the event +of a conflict.) +.Pp +.Va defaults +contains a list of default sources to try if +.Xr nsswitch.conf 5 +is missing or corrupted, or if there is no relevant entry for +.Va database . +It is an array of +.Va ns_src +structures, which have the following format: +.Bd -literal -offset indent +typedef struct _ns_src { + const char *src; + u_int32_t flags; +} ns_src; +.Ed +.Bd -ragged -offset indent +The +.Fa defaults +array should consist of one entry for each source to be configured by +default indicated by +.Va src , +and +.Va flags +set to the criterion desired +(usually +.Dv NS_SUCCESS ; +refer to +.Sx Method return values +for more information). +The last entry in +.Va defaults +should have +.Va src +set to +.Dv NULL +and +.Va flags +set to 0. +.Pp +For convenience, a global variable defined as: +.Dl extern const ns_src __nsdefaultsrc[]; +exists which contains a single default entry for the source +.Sq files +that may be used by callers which do not require complicated default +rules. +.Ed +.Pp +.Sq Va ... +are optional extra arguments, which are passed to the appropriate method +as a variable argument list of the type +.Vt va_list . +.Ss Valid source types +While there is support for arbitrary sources, the following +#defines for commonly implemented sources are available: +.Bl -column NSSRC_COMPAT compat -offset indent +.It Sy "#define value" +.It Dv NSSRC_FILES Ta """files"" +.It Dv NSSRC_DB Ta """db"" +.It Dv NSSRC_DNS Ta """dns"" +.It Dv NSSRC_NIS Ta """nis"" +.It Dv NSSRC_COMPAT Ta """compat"" +.El +.Pp +Refer to +.Xr nsswitch.conf 5 +for a complete description of what each source type is. +.Pp +.Ss Method return values +The +.Vt nss_method +functions must return one of the following values depending upon status +of the lookup: +.Bl -column "Return value" "Status code" +.It Sy "Return value Status code" +.It Dv NS_SUCCESS Ta success +.It Dv NS_NOTFOUND Ta notfound +.It Dv NS_UNAVAIL Ta unavail +.It Dv NS_TRYAGAIN Ta tryagain +.It Dv NS_RETURN Ta -none- +.El +.Pp +Refer to +.Xr nsswitch.conf 5 +for a complete description of each status code. +.Pp +The +.Fn nsdispatch +function returns the value of the method that caused the dispatcher to +terminate, or +.Dv NS_NOTFOUND +otherwise. +.Sh NOTES +.Fx Ns 's +.Lb libc +provides stubs for compatibility with NSS modules +written for the +.Tn GNU +C Library +.Nm nsswitch +interface. +However, these stubs only support the use of the +.Dq Li passwd +and +.Dq Li group +databases. +.Sh SEE ALSO +.Xr hesiod 3 , +.Xr stdarg 3 , +.Xr nsswitch.conf 5 , +.Xr yp 8 +.Sh HISTORY +The +.Fn nsdispatch +function first appeared in +.Fx 5.0 . +It was imported from the +.Nx +Project, +where it appeared first in +.Nx 1.4 . +Support for NSS modules first appeared in +.Fx 5.1 . +.Sh AUTHORS +Luke Mewburn +.Aq lukem@netbsd.org +wrote this freely-distributable name-service switch implementation, +using ideas from the +.Tn ULTRIX +svc.conf(5) +and +.Tn Solaris +nsswitch.conf(4) +manual pages. +The +.Fx +Project +added the support for threads and NSS modules, and normalized the uses +of +.Fn nsdispatch +within the standard C library. |
