SunOS man pages : yp_match (3)
Networking Services Library Functions ypclnt(3NSL)
NAME
ypclnt, yp_get_default_domain, yp_bind, yp_unbind, yp_match,
yp_first, yp_next, yp_all, yp_order, yp_master,
yperr_string, ypprot_err - NIS Version 2 client interface
SYNOPSIS
cc [ flag ... ] file ... -lnsl [ library ... ]
#include <rpcsvc/ypclnt.h>
#include <rpcsvc/yp_prot.h>
DESCRIPTION
This package of functions provides an interface to NIS, Net-
work Information Service Version 2, formerly referred to as
YP. In this version of SunOS, NIS version 2 is supported
only for compatibility with previous versions. The recom-
mended enterprise level information service is NIS+ or NIS
version 3, see nis+(1). Moreover, this version of SunOS
supports only the client interface to NIS version 2. It is
expected that this client interface will be served either by
an existing ypserv process running on another machine on the
network that has an earlier version of SunOS or by an NIS+
server, see rpc.nisd(1M), running in "YP-compatibility
mode". Refer to the NOTES section in ypfiles(4) for implica-
tions of being an NIS client of an NIS+ server in "YP-
compatibility mode", and to ypbind(1M), ypwhich(1),
ypmatch(1), and ypcat(1) for commands to access NIS from a
client machine. The package can be loaded from the standard
library, /usr/lib/libnsl.so.1.
All input parameter names begin with in. Output parameters
begin with out. Output parameters of type char ** should be
addresses of uninitialized character pointers. Memory is
allocated by the NIS client package using malloc(3C), and
may be freed by the user code if it has no continuing need
for it. For each outkey and outval, two extra bytes of
memory are allocated at the end that contain NEWLINE and
null, respectively, but these two bytes are not reflected in
outkeylen or outvallen . indomain and inmap strings must be
non-null and null-terminated. String parameters which are
accompanied by a count parameter may not be null, but may
point to null strings, with the count parameter indicating
this. Counted strings need not be null-terminated.
All functions in this package of type int return 0 if they
succeed, and a failure code (YPERR_xxxx) otherwise. Failure
codes are described in the ERRORS section.
Routines
yp_bind (char *indomain);
To use the NIS name services, the client process must
be "bound" to an NIS server that serves the appropri-
ate domain using yp_bind(). Binding need not be done
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Networking Services Library Functions ypclnt(3NSL)
explicitly by user code; this is done automatically
whenever an NIS lookup function is called. yp_bind()
can be called directly for processes that make use of
a backup strategy (for example, a local file) in cases
when NIS services are not available. If a process
calls yp_bind(), it should call yp_unbind() when it is
done using NIS in order to free up resources.
void yp_unbind(char *indomain);
Each binding allocates (uses up) one client process
socket descriptor; each bound domain costs one socket
descriptor. However, multiple requests to the same
domain use that same descriptor. yp_unbind() is avail-
able at the client interface for processes that expli-
citly manage their socket descriptors while accessing
multiple domains. The call to yp_unbind() makes the
domain unbound, and frees all per-process and per-node
resources used to bind it.
If an RPC failure results upon use of a binding, that
domain will be unbound automatically. At that point,
the ypclnt() layer will retry a few more times or
until the operation succeeds, provided that
rpcbind(1M) and ypbind(1M) are running, and either
o the client process cannot bind a server for the
proper domain, or
o RPC requests to the server fail.
If an error is not RPC-related, or if rpcbind is not
running, or if ypbind is not running, or if a bound
ypserv process returns any answer (success or
failure), the ypclnt layer will return control to the
user code, either with an error code, or a success
code and any results.
yp_get_default_domain (char **outdomain);
The NIS lookup calls require a map name and a domain
name, at minimum. It is assumed that the client pro-
cess knows the name of the map of interest. Client
processes should fetch the node's default domain by
calling yp_get_default_domain(), and use the returned
outdomain as the indomain parameter to successive NIS
name service calls. The domain thus returned is the
same as that returned using the SI_SRPC_DOMAIN command
to the sysinfo(2) system call. The value returned in
outdomain should not be freed.
yp_match(char *indomain,
char *inmap, char *inkey, int inkeylen, char **outval,
int *outvallen);" 6 yp_match() returns the value
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Networking Services Library Functions ypclnt(3NSL)
associated with a passed key. This key must be exact;
no pattern matching is available. yp_match() requires
a full YP map name; for example, hosts.byname instead
of the nickname hosts.
yp_first(char *indomain,
char *inmap, char **outkey, int *outkeylen, char
**outval, int *outvallen);" 6 yp_first() returns the
first key-value pair from the named map in the named
domain.
yp_next(char *indomain, char
*inmap, char *inkey, int inkeylen, char **outkey, int
*outkeylen, char **outval, int *outvallen);" 6
yp_next() returns the next key-value pair in a named
map. The inkey parameter must be the outkey returned
from an initial call to yp_first() (to get the second
key-value pair) or the one returned from the nth call
to yp_next() (to get the nth + second key-value pair).
Similarly, the inkeylen parameter must be the
outkeylen returned from the earlier yp_first() or
yp_next() call.
The concept of first (and, for that matter, of next)
is particular to the structure of the NIS map being
processing; there is no relation in retrieval order to
either the lexical order within any original (non-NIS
name service) data base, or to any obvious numerical
sorting order on the keys, values, or key-value pairs.
The only ordering guarantee made is that if the
yp_first() function is called on a particular map, and
then the yp_next() function is repeatedly called on
the same map at the same server until the call fails
with a reason of YPERR_NOMORE, every entry in the data
base will be seen exactly once. Further, if the same
sequence of operations is performed on the same map at
the same server, the entries will be seen in the same
order.
Under conditions of heavy server load or server
failure, it is possible for the domain to become
unbound, then bound once again (perhaps to a different
server) while a client is running. This can cause a
break in one of the enumeration rules; specific
entries may be seen twice by the client, or not at
all. This approach protects the client from error mes-
sages that would otherwise be returned in the midst of
the enumeration. The next paragraph describes a better
solution to enumerating all entries in a map.
yp_all(char *indomain, char
*inmap, struct ypall_callback *incallback);" 6 The
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Networking Services Library Functions ypclnt(3NSL)
function yp_all() provides a way to transfer an entire
map from server to client in a single request using
TCP (rather than UDP as with other functions in this
package). The entire transaction take place as a sin-
gle RPC request and response. yp_all() can be used
just like any other NIS name service procedure, iden-
tify the map in the normal manner, and supply the name
of a function which will be called to process each
key-value pair within the map. The call to yp_all()
returns only when the transaction is completed (suc-
cessfully or unsuccessfully), or the foreach() func-
tion decides that it does not want to see any more
key-value pairs.
The third parameter to yp_all() is
struct ypall_callback *incallback {
int (*foreach)();
char *data;
};
The function foreach() is called
foreach(int instatus, char *inkey,
int inkeylen, char *inval,
int invallen, char *indata);
The instatus parameter will hold one of the
return status values defined in <rpcsvc/yp_prot.h
- either YP_TRUE or an error code. (See
ypprot_err(), below, for a function which con-
verts an NIS name service protocol error code to
a ypclnt layer error code.)
The key and value parameters are somewhat dif-
ferent than defined in the synopsis section
above. First, the memory pointed to by the inkey
and inval parameters is private to the yp_all()
function, and is overwritten with the arrival of
each new key-value pair. It is the responsibility
of the foreach() function to do something useful
with the contents of that memory, but it does not
own the memory itself. Key and value objects
presented to the foreach() function look exactly
as they do in the server's map - if they were not
NEWLINE-terminated or null-terminated in the map,
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Networking Services Library Functions ypclnt(3NSL)
they will not be here either.
The indata parameter is the contents of the
incallback=>data element passed to yp_all(). The
data element of the callback structure may be
used to share state information between the
foreach() function and the mainline code. Its
use is optional, and no part of the NIS client
package inspects its contents - cast it to some-
thing useful, or ignore it.
The foreach() function is a Boolean. It
should return 0 to indicate that it wants to
be called again for further received key-
value pairs, or non-zero to stop the flow of
key-value pairs. If foreach() returns a
non-zero value, it is not called again; the
functional value of yp_all() is then 0.
yp_order(char *indomain,
char *inmap, unsigned long *outorder);" 6
yp_order() returns the order number for a
map. This function is not supported if the
ypbind process on the client's system is
bound to an NIS+ server running in "YP-
compatibility mode".
yp_master(char *indomain,
char *inmap, char **outname);" 6 yp_master()
returns the machine name of the master NIS
server for a map.
char *yperr_string(int incode);
yperr_string() returns a pointer to an
error message string that is null-
terminated but contains no period or <NEW-
LINE>.
ypprot_err (unsigned int incode);
ypprot_err() takes an NIS name service pro-
tocol error code as input, and returns a
ypclnt layer error code, which may be used
in turn as an input to yperr_string().
RETURN VALUES
All integer functions return 0 if the requested operation is
successful, or one of the following errors if the operation
fails.
YPERR_ACCESS
Access violation.
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YPERR_BADARGS
The arguments to the function are bad.
YPERR_BADDB
The YP database is bad.
YPERR_BUSY
The database is busy.
YPERR_DOMAIN
Cannot bind to server on this domain.
YPERR_KEY
No such key in map.
YPERR_MAP
No such map in server's domain.
YPERR_NODOM
Local domain name not set.
YPERR_NOMORE
No more records in map database.
YPERR_PMAP
Cannot communicate with rpcbind.
YPERR_RESRC
Resource allocation failure.
YPERR_RPC
RPC failure; domain has been unbound.
YPERR_YPBIND
Cannot communicate with ypbind.
YPERR_YPERR
Internal YP server or client error.
YPERR_YPSERV
Cannot communicate with ypserv.
YPERR_VERS
YP version mismatch.
FILES
/usr/lib/libnsl.so.1
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
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Networking Services Library Functions ypclnt(3NSL)
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| MT-Level | Safe |
|_____________________________|_____________________________|
SEE ALSO
nis+(1), ypcat(1), ypmatch(1), ypwhich(1), rpc.nisd(1M),
rpcbind(1M), ypbind(1M), ypserv(1M), sysinfo(2), malloc(3C),
ypfiles(4), attributes(5)
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