RPC_CLNT_CREATE(3) FreeBSD Library Functions Manual RPC_CLNT_CREATE(3)
NAME
rpc_clnt_create, clnt_control, clnt_create, clnt_create_timed,
clnt_create_vers, clnt_create_vers_timed, clnt_destroy, clnt_dg_create,
clnt_pcreateerror, clnt_raw_create, clnt_spcreateerror, clnt_tli_create,
clnt_tp_create, clnt_tp_create_timed, clnt_vc_create, rpc_createerr -
library routines for dealing with creation and manipulation of CLIENT
handles
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <rpc/rpc.h>
bool_t
clnt_control(CLIENT *clnt, const u_int req, char *info);
CLIENT *
clnt_create(const char * host, const rpcprog_t prognum,
const rpcvers_t versnum, const char *nettype);
CLIENT *
clnt_create_timed(const char * host, const rpcprog_t prognum,
const rpcvers_t versnum, const char *nettype,
const struct timeval *timeout);
CLIENT *
clnt_create_vers(const char * host, const rpcprog_t prognum,
rpcvers_t *vers_outp, const rpcvers_t vers_low,
const rpcvers_t vers_high, const char *nettype);
CLIENT *
clnt_create_vers_timed(const char * host, const rpcprog_t prognum,
rpcvers_t *vers_outp, const rpcvers_t vers_low,
const rpcvers_t vers_high, const char *nettype,
const struct timeval *timeout);
void
clnt_destroy(CLIENT *clnt);
CLIENT *
clnt_dg_create(const int fildes, const struct netbuf *svcaddr,
const rpcprog_t prognum, const rpcvers_t versnum, const u_int sendsz,
const u_int recvsz);
void
clnt_pcreateerror(const char *s);
char *
clnt_spcreateerror(const char *s);
CLIENT *
clnt_raw_create(const rpcprog_t prognum, const rpcvers_t versnum);
CLIENT *
clnt_tli_create(const int fildes, const struct netconfig *netconf,
struct netbuf *svcaddr, const rpcprog_t prognum,
const rpcvers_t versnum, const u_int sendsz, const u_int recvsz);
CLIENT *
clnt_tp_create(const char * host, const rpcprog_t prognum,
const rpcvers_t versnum, const struct netconfig *netconf);
CLIENT *
clnt_tp_create_timed(const char * host, const rpcprog_t prognum,
const rpcvers_t versnum, const struct netconfig *netconf,
const struct timeval *timeout);
CLIENT *
clnt_vc_create(const int fildes, const struct netbuf *svcaddr,
const rpcprog_t prognum, const rpcvers_t versnum, u_int sendsz,
u_int recvsz);
DESCRIPTION
RPC library routines allow C language programs to make procedure calls on
other machines across the network. First a CLIENT handle is created and
then the client calls a procedure to send a request to the server. On
receipt of the request, the server calls a dispatch routine to perform
the requested service, and then sends a reply.
Routines
clnt_control()
A function macro to change or retrieve various information about
a client object. The req argument indicates the type of
operation, and info is a pointer to the information. For both
connectionless and connection-oriented transports, the supported
values of req and their argument types and what they do are:
CLSET_TIMEOUT struct timeval * set total timeout
CLGET_TIMEOUT struct timeval * get total timeout
Note: if you set the timeout using clnt_control(), the timeout
argument passed by clnt_call() is ignored in all subsequent
calls.
Note: If you set the timeout value to 0, clnt_control()
immediately returns an error (RPC_TIMEDOUT). Set the timeout
argument to 0 for batching calls.
CLGET_SVC_ADDR struct netbuf * get servers address
CLGET_FD int * get fd from handle
CLSET_FD_CLOSE void close fd on destroy
CLSET_FD_NCLOSE void do not close fd on
destroy
CLGET_VERS uint32_t * get RPC program version
CLSET_VERS uint32_t * set RPC program version
CLGET_XID uint32_t * get XID of previous call
CLSET_XID uint32_t * set XID of next call
The following operations are valid for connectionless transports
only:
CLSET_RETRY_TIMEOUT struct timeval * set the retry timeout
CLGET_RETRY_TIMEOUT struct timeval * get the retry timeout
CLSET_CONNECT int * use connect(2)
The retry timeout is the time that RPC waits for the server to
reply before retransmitting the request. The clnt_control()
function returns TRUE on success and FALSE on failure.
clnt_create()
Generic client creation routine for program prognum and version
versnum. The host argument identifies the name of the remote
host where the server is located. The nettype argument
indicates the class of transport protocol to use. The
transports are tried in left to right order in NETPATH
environment variable or in top to bottom order in the netconfig
database. The clnt_create() function tries all the transports
of the nettype class available from the NETPATH environment
variable and the netconfig database, and chooses the first
successful one. A default timeout is set and can be modified
using clnt_control(). This routine returns NULL if it fails.
The clnt_pcreateerror() routine can be used to print the reason
for failure.
Note: clnt_create() returns a valid client handle even if the
particular version number supplied to clnt_create() is not
registered with the rpcbind(8) service. This mismatch will be
discovered by a clnt_call() later (see rpc_clnt_calls(3)).
clnt_create_timed()
Generic client creation routine which is similar to
clnt_create() but which also has the additional argument timeout
that specifies the maximum amount of time allowed for each
transport class tried. In all other respects, the
clnt_create_timed() call behaves exactly like the clnt_create()
call.
clnt_create_vers()
Generic client creation routine which is similar to
clnt_create() but which also checks for the version
availability. The host argument identifies the name of the
remote host where the server is located. The nettype argument
indicates the class transport protocols to be used. If the
routine is successful it returns a client handle created for the
highest version between vers_low and vers_high that is supported
by the server. The vers_outp argument is set to this value.
That is, after a successful return vers_low <= *vers_outp <=
vers_high. If no version between vers_low and vers_high is
supported by the server then the routine fails and returns NULL.
A default timeout is set and can be modified using
clnt_control(). This routine returns NULL if it fails. The
clnt_pcreateerror() routine can be used to print the reason for
failure. Note: clnt_create() returns a valid client handle even
if the particular version number supplied to clnt_create() is
not registered with the rpcbind(8) service. This mismatch will
be discovered by a clnt_call() later (see rpc_clnt_calls(3)).
However, clnt_create_vers() does this for you and returns a
valid handle only if a version within the range supplied is
supported by the server.
clnt_create_vers_timed()
Generic client creation routine which is similar to
clnt_create_vers() but which also has the additional argument
timeout that specifies the maximum amount of time allowed for
each transport class tried. In all other respects, the
clnt_create_vers_timed() call behaves exactly like the
clnt_create_vers() call.
clnt_destroy()
A function macro that destroys the client's RPC handle.
Destruction usually involves deallocation of private data
structures, including clnt itself. Use of clnt is undefined
after calling clnt_destroy(). If the RPC library opened the
associated file descriptor, or CLSET_FD_CLOSE was set using
clnt_control(), the file descriptor will be closed. The caller
should call auth_destroy(clnt->cl_auth) (before calling
clnt_destroy()) to destroy the associated AUTH structure (see
rpc_clnt_auth(3)).
clnt_dg_create()
This routine creates an RPC client for the remote program
prognum and version versnum; the client uses a connectionless
transport. The remote program is located at address svcaddr.
The fildes argument is an open and bound file descriptor. This
routine will resend the call message in intervals of 15 seconds
until a response is received or until the call times out. The
total time for the call to time out is specified by clnt_call()
(see clnt_call() in rpc_clnt_calls(3)). The retry time out and
the total time out periods can be changed using clnt_control().
The user may set the size of the send and receive buffers with
the sendsz and recvsz arguments; values of 0 choose suitable
defaults. This routine returns NULL if it fails.
clnt_pcreateerror()
Print a message to standard error indicating why a client RPC
handle could not be created. The message is prepended with the
string s and a colon, and appended with a newline.
clnt_spcreateerror()
Like clnt_pcreateerror(), except that it returns a string
instead of printing to the standard error. A newline is not
appended to the message in this case. Warning: returns a
pointer to a buffer that is overwritten on each call.
clnt_raw_create()
This routine creates an RPC client handle for the remote program
prognum and version versnum. The transport used to pass
messages to the service is a buffer within the process's address
space, so the corresponding RPC server should live in the same
address space; (see svc_raw_create() in rpc_svc_create(3)).
This allows simulation of RPC and measurement of RPC overheads,
such as round trip times, without any kernel or networking
interference. This routine returns NULL if it fails. The
clnt_raw_create() function should be called after
svc_raw_create().
clnt_tli_create()
This routine creates an RPC client handle for the remote program
prognum and version versnum. The remote program is located at
address svcaddr. If svcaddr is NULL and it is connection-
oriented, it is assumed that the file descriptor is connected.
For connectionless transports, if svcaddr is NULL,
RPC_UNKNOWNADDR error is set. The fildes argument is a file
descriptor which may be open, bound and connected. If it is
RPC_ANYFD, it opens a file descriptor on the transport specified
by netconf. If fildes is RPC_ANYFD and netconf is NULL, a
RPC_UNKNOWNPROTO error is set. If fildes is unbound, then it
will attempt to bind the descriptor. The user may specify the
size of the buffers with the sendsz and recvsz arguments; values
of 0 choose suitable defaults. Depending upon the type of the
transport (connection-oriented or connectionless),
clnt_tli_create() calls appropriate client creation routines.
This routine returns NULL if it fails. The clnt_pcreateerror()
routine can be used to print the reason for failure. The remote
rpcbind service (see rpcbind(8)) is not consulted for the
address of the remote service.
clnt_tp_create()
Like clnt_create() except clnt_tp_create() tries only one
transport specified through netconf. The clnt_tp_create()
function creates a client handle for the program prognum, the
version versnum, and for the transport specified by netconf.
Default options are set, which can be changed using
clnt_control() calls. The remote rpcbind service on the host
host is consulted for the address of the remote service. This
routine returns NULL if it fails. The clnt_pcreateerror()
routine can be used to print the reason for failure.
clnt_tp_create_timed()
Like clnt_tp_create() except clnt_tp_create_timed() has the
extra argument timeout which specifies the maximum time allowed
for the creation attempt to succeed. In all other respects, the
clnt_tp_create_timed() call behaves exactly like the
clnt_tp_create() call.
clnt_vc_create()
This routine creates an RPC client for the remote program
prognum and version versnum; the client uses a connection-
oriented transport. The remote program is located at address
svcaddr. The fildes argument is an open and bound file
descriptor. The user may specify the size of the send and
receive buffers with the sendsz and recvsz arguments; values of
0 choose suitable defaults. This routine returns NULL if it
fails. The address svcaddr should not be NULL and should point
to the actual address of the remote program. The
clnt_vc_create() function does not consult the remote rpcbind
service for this information.
struct rpc_createerr rpc_createerr;
A global variable whose value is set by any RPC client handle
creation routine that fails. It is used by the routine
clnt_pcreateerror() to print the reason for the failure.
SEE ALSO
rpc(3), rpc_clnt_auth(3), rpc_clnt_calls(3), rpcbind(8)
FreeBSD 13.1-RELEASE-p6 May 7, 1993 FreeBSD 13.1-RELEASE-p6
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