 |
» |
|
|
|
NAMErpc_clnt_create, clnt_control, clnt_create, clnt_create_vers, clnt_destroy, clnt_dg_create, clnt_pcreateerror, clnt_raw_create, clnt_spcreateerror, clnt_tli_create, clnt_tp_create, clnt_vc_create, rpc_createerr — library routines for dealing with creation and manipulation of CLIENT handles SYNOPSIS#include <rpc/rpc.h> bool_t clnt_control(CLIENT *clnt,
const u_int req,
char *info); CLIENT *clnt_create(const char *host,
const u_long prognum,
const u_long versnum,
const char *nettype); CLIENT *clnt_create_vers(const char *host,
const u_long prognum,
u_long *vers_outp,
const u_long vers_low,
const u_long vers_high,
char *nettype); void clnt_destroy(CLIENT *clnt); CLIENT *clnt_dg_create(const int fildes,
const struct netbuf *svcaddr,
const u_long prognum,
const u_long versnum,
const u_int sendsz,
const u_int recvsz); void clnt_pcreateerror(const char *s); CLIENT *clnt_raw_create(const u_long prognum,
const u_long versnum); char *clnt_spcreateerror(const char *s); CLIENT *clnt_tli_create(const int fildes,
const struct netconfig *netconf,
const struct netbuf *svcaddr,
const_long prognum,
const u_long versnum,
const u_int sendsz,
const u_int recvsz); CLIENT *clnt_tp_create(const char *host,
const u_long prognum,
const u_long versnum,
const struct netconfig *netconf); CLIENT *clnt_vc_create(const int fildes,
const struct netbuf *svcaddr,
const u_long prognum,
const u_long versnum,
const u_int sendsz,
const u_int recvsz); struct rpc_createerr rpc_createerr; DESCRIPTIONRPC
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. These routines are MT-Safe.
In the case of multithreaded applications, the
_REENTRANT
flag must be defined on the command line at compilation time
(-D_REENTRANT).
When the
_REENTRANT
flag is defined,
rpc_createerr
becomes a macro which enables each thread
to have its own
rpc_createerr. RoutinesSee
rpc(3N)
for the definition of the
CLIENT
data structure.
- bool_t clnt_control();
A function macro to change or retrieve various information
about a client object.
req
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_call()
immediately returns an error
(RPC_TIMEDOUT).
Set the timeout parameter to
0
for batching calls. CLGET_FD int * get the associated file descriptor
CLGET_SVC_ADDR struct netbuf * get servers address
CLSET_FD_CLOSE void * close the file descriptor
when destroying the client handle
(see clnt_destroy())
CLSET_FD_NCLOSE void do not close the file descriptor
when destroying the client handle
CLGET_VERS unsigned long * get the RPC program's
version number associated with the
client handle
CLSET_VERS unsigned long * set the RPC program's version
number associated with the
client handle. This assumes
that the RPC server for
this new version is still
listening at the address of the
previous version.
CLGET_XID unsigned long * get the XID of the previous
remote procedure call
CLSET_XID unsigned long * set the XID of the next
remote procedure 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 The retry timeout is the time that
RPC
waits for the server to reply before retransmitting the request. clnt_control()
returns
TRUE
on success and
FALSE
on failure. - CLIENT *clnt_create()
Generic client creation routine for program
prognum
and version
versnum.
host
identifies the name of the remote host where the server
is located.
nettype
indicates the class of transport protocol to use.
The transports are tried in left to right order in
NETPATH
variable or in top to bottom order in
the netconfig database. clnt_create()
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
service.
This mismatch will be discovered by a
clnt_call
later (see
rpc_clnt_calls(3N)). - CLIENT *clnt_create_vers()
Generic client creation routine which is similar to
clnt_create()
but which also checks for the
version availability.
host
identifies the name of the remote host where the server
is located.
nettype
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.
vers_outp
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
service.
This mismatch will be discovered by a
clnt_call
later (see
rpc_clnt_calls(3N)).
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. - void 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(3N)). - CLIENT *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 parameter
fildes
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(3N)).
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 parameters
sendsz
and
recvsz;
values of
0
choose suitable defaults.
This routine returns
NULL
if it fails. - void 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. - CLIENT *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(3N)).
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.
clnt_raw_create()
should be called after
svc_raw_create(). - char *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. In multithread applications, this
buffer is implemented as thread-specific data. - CLIENT *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.
fildes
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 parameters
sendsz
and
recvsz;
values of
0choosesuitabledefaults.
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(1M))
is not consulted for the address of the remote
service. - CLIENT *clnt_tp_create()
Like
clnt_create()
except
clnt_tp_create()
tries only one transport specified through
netconf. clnt_tp_create()
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. - CLIENT *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 parameter
fildes
is an open and bound file descriptor.
The user may specify the size of the send and receive buffers
with the parameters
sendsz
and
recvsz;
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.
clnt_vc_create()
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. In multithreaded applications,
rpc_createerr
becomes a macro which enables each thread
to have its own
rpc_createerr.
MULTITHREAD USAGE- Thread Safe:
Yes - Cancel Safe:
Yes - Fork Safe:
No - Async-cancel Safe:
No - Async-signal Safe:
No
These functions can be called safely in a multithreaded environment. They
may be cancellation points in that they call functions that are cancel
points. In a multithreaded environment, these functions are
not safe to be called by a child process after
fork()
and before
exec().
These functions should not be called by a multithreaded application
that support asynchronous cancellation or asynchronous signals. |
