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#include <rpcsvc/ypclnt.h> #include <rpcsvc/yp_prot.h>int yp_bind (char *indomain);
void yp_unbind (char *indomain);
int yp_get_default_domain (char **outdomain);
int yp_match(char *indomain, char *inmap, char *inkey, int inkeylen, char **outval, int *outvallen);
int yp_first(char *indomain, char *inmap, char **outkey, int *outkeylen, char **outval, int *outvallen);
int yp_next(char *indomain, char *inmap, char *inkey, int inkeylen, char **outkey, int *outkeylen, char **outval, int *outvallen);
int yp_all(char *indomain, char *inmap, struct ypall_callback *incallback);
int yp_order(char *indomain, char *inmap, int *outorder);
int yp_master(char *indomain, char *inmap, char **outname);
const char *yperr_string(int incode);
int ypprot_err (unsigned int incode);
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 if the user code 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.
Functions requiring a full YP map name cannot use nicknames.
For example, hosts.byname must be used instead of the
nickname hosts.
Failure codes are described in the ``Return values'' section.
int yp_bind (char *indomain);To use the NIS name services, the client process must be ``bound'' to a NIS server that serves the appropriate domain using yp_bind. Binding need not be done explicitly by user code; this is done automatically whenever a 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.
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 available at the client interface for processes that explicitly manage their socket descriptors while accessing multiple domains. The call to yp_unbind make the domain ``unbound'', and free 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 forever or until the operation succeeds, provided that ypbind is running, and either the client process cannot bind a server for the proper domain or RPC requests to the server fail.
If an error is not RPC-related, 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.
int 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 process 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.
int yp_match(char *indomain, char *inmap, char *inkey, int inkeylen, char **outval, int *outvallen);yp_match returns the value associated with a passed key. This key must be exact; no pattern matching is available.
int yp_first(char *indomain, char *inmap, char **outkey, int *outkeylen, char **outval, int *outvallen);yp_first returns the first key-value pair from the named map in the named domain.
int yp_next(char *indomain, char *inmap, char *inkey, int inkeylen, char **outkey, int *outkeylen, char **outval, int *outvallen);yp_next returns the next key-value pair in a named map. The inkey parameter should 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).
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 messages 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.
int yp_all(char *indomain, char *inmap, struct ypall_callback *incallback);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 single RPC request and response. yp_all can be used just like any other NIS name service procedure, identify 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 (successfully or unsuccessfully), or the foreach function 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:
int 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 the description of ypprot_err for a function which converts a NIS name service protocol error code to a ypclnt layer error code.)
The key and value parameters are somewhat different from those defined in the ``Synopsis'' section. 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, 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 something useful,
or ignore it.
The foreach function is a boolean. It should return zero 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.
int yp_order(char *indomain, char *inmap, int *outorder);yp_order returns the order number for a map.
int yp_master(char *indomain, char *inmap, char **outname);yp_master returns the machine name of the master NIS server for a map.
const char *yperr_string(int incode);yperr_string returns a pointer to a read-only error message string that is NULL-terminated but contains no period or newline.
int ypprot_err (unsigned int incode);ypprot_err takes a NIS name service protocol error code as input, and returns a ypclnt layer error code, which may be used in turn as an input to yperr_string.
| 1 | YPERR_BADARGS | Args to function are bad |
| 2 | YPERR_RPC | RPC failure - domain has been unbound |
| 3 | YPERR_DOMAIN | Cannot bind to server in this domain |
| 4 | YPERR_MAP | No such map in server's domain |
| 5 | YPERR_KEY | No such key in map |
| 6 | YPERR_YPERR | Internal NIS server or client error |
| 7 | YPERR_RESRC | Resource allocation failure |
| 8 | YPERR_NOMORE | No more records in map database |
| 9 | YPERR_PMAP | Cannot communicate with RPC binder |
| 10 | YPERR_YPBIND | Cannot communicate with ypbind |
| 11 | YPERR_YPSERV | Cannot communicate with ypserv |
| 12 | YPERR_NODOM | Local domain name not set |
| 13 | YPERR_BADDB | NIS database is bad |
| 14 | YPERR_VERS | NIS version mismatch |
| 15 | YPERR_ACCESS | Access violation |
| 16 | YPERR_BUSY | Database busy |