YPCLNT(3) | Library Functions Manual | YPCLNT(3) |
int
yp_all(const char *indomain, const char *inmap, struct ypall_callback *incallback);
int
yp_bind(const char *dom);
int
yp_first(const char *indomain, const char *inmap, char **outkey, int *outkeylen, char **outval, int *outvallen);
int
yp_get_default_domain(char **outdomain);
int
yp_master(const char *indomain, const char *inmap, char **outname);
int
yp_match(const char *indomain, const char *inmap, const char *inkey, int inkeylen, char **outval, int *outvallen);
int
yp_next(const char *indomain, const char *inmap, const char *inkey, int inkeylen, char **outkey, int *outkeylen, char **outval, int *outvallen);
int
yp_order(const char *indomain, const char *inmap, int *outorder);
void
yp_unbind(const char *dom);
char *
yperr_string(int incode);
int
ypprot_err(unsigned int incode);
For all functions, input values begin with in and output values begin with out.
Any output values of type char ** should be the addresses of uninitialized character pointers. These values will be reset to the null pointer (unless the address itself is the null pointer, in which case the error YPERR_BADARGS will be returned). If necessary, memory will be allocated by the YP client routines using malloc(), and the result will be stored in the appropriate output value. If the invocation of a YP client routine doesn't return an error, and an output value is not the null pointer, then this memory should be freed by the user when there is no additional need for the data stored there. For outkey and outval, two extra bytes of memory are allocated for a ‘\n
' and ‘\0
', which are not reflected in the values of outkeylen or outvallen.
All occurrences of indomain and inmap must be non-null, NUL-terminated strings. All input strings which also have a corresponding length parameter cannot be the null pointer unless the corresponding length value is zero. Such strings need not be NUL-terminated.
All YP lookup calls (the functions yp_all(), yp_first(), yp_master(), yp_match(), yp_next(), yp_order()) require a YP domain name and a YP map name. The default domain name may be obtained by calling yp_get_default_domain(), and should thus be used before all other YP calls in a client program. The value it places outdomain is suitable for use as the indomain parameter to all subsequent YP calls.
In order for YP lookup calls to succeed, the client process must be bound to a YP server process. The client process need not explicitly bind to the server, as it happens automatically whenever a lookup occurs. The function yp_bind() is provided for a backup strategy, e.g. a local file, when a YP server process is not available. Each binding uses one socket descriptor on the client process, which may be explicitly freed using yp_unbind(), which frees all per-process and per-node resources to bind the domain and marks the domain unbound.
If, during a YP lookup, an RPC failure occurs, the domain used in the lookup is automatically marked unbound and the ypclnt layer retries the lookup as long as ypbind(8) is running and either the client process cannot bind to a server for the domain specified in the lookup, or RPC requests to the YP server process fail. If an error is not RPC-related, one of the YP error codes described below is returned and control given back to the user code.
The ypclnt suite provides the following functionality:
Of course, the notions of “first” and “next” are particular to the type of YP map being accessed, and thus there is no guarantee of lexical order. The only guarantees provided with yp_first() and yp_next(), providing that the same map on the same server is polled repeatedly until yp_next() returns YPERR_NOMORE, are that all key-value pairs in that map will be accessed exactly once, and if the entire procedure is repeated, the order will be the same.
If the server is heavily loaded or the server fails for some reason, the domain being used may become unbound. If this happens, and the client process re-binds, the retrieval rules will break: some entries may be seen twice, and others not at all. For this reason, the function yp_all() provides a better solution for reading all of the entries in a particular map.
struct ypall_callback *incallback { int (*foreach)(); char *data; };
The char *data argument is an opaque pointer for use by the callback function. The foreach function should return non-zero when it no longer wishes to process key-value pairs, at which time yp_all() returns a value of 0, and is called with the following arguments:
int foreach ( int instatus, char *inkey, int inkeylen, char *inval, int invallen, char *indata );
Where:
\n
' or ‘\0
' in the map, then they will not be terminated as such when given to the foreach function, either..
' or ‘\n
'.May 21, 1997 | NetBSD 6.1 |