RPC_SVC_CALLS(3NSL) Networking Services Library Functions RPC_SVC_CALLS(3NSL)
NAME
rpc_svc_calls, svc_dg_enablecache, svc_done, svc_exit, svc_fdset,
svc_freeargs, svc_getargs, svc_getreq_common, svc_getreq_poll,
svc_getreqset, svc_getrpccaller, svc_max_pollfd, svc_pollfd, svc_run,
svc_sendreply, svc_getcallerucred, svc_fd_negotiate_ucred - library
routines for RPC servers
SYNOPSIS
cc [
flag... ]
file...
-lnsl [
library...]
#include <rpc/rpc.h>
int svc_dg_enablecache(
SVCXPRT *xprt,
const uint_t cache_size);
int svc_done(
SVCXPRT *xprt);
void svc_exit(
void);
void svc_fd_negotiate_ucred(
int fd);
bool_t svc_freeargs(
const SVCXPRT *xprt,
const txdrproc_t inproc,
caddr_t in);
bool_t svc_getargs(
const SVCXPRT *xprt,
const xdrproc_t inproc,
caddr_t in);
int svc_getcallerucred(
const SVCXPRT *xprt,
ucred_t **ucred);
void svc_getreq_common(
const int fd);
void svc_getreqset(
fd_set *rdfds);
void svc_getreq_poll(
struct pollfd *pfdp,
const int pollretval);
struct netbuf *svc_getrpccaller(
const SVCXPRT *xprt);
void svc_run(
void);
bool_t svc_sendreply(
const SVCXPRT *xprt,
const xdrproc_t outproc,
caddr_t out);
int svc_max_pollfd;
fd_set svc_fdset;
pollfd_t *svc_pollfd;
DESCRIPTION
These routines are part of the
RPC library which allows C language
programs to make procedure calls on other machines across the network.
These routines are associated with the server side of the
RPC mechanism.
Some of them are called by the server side dispatch function. Others,
such as
svc_run(), are called when the server is initiated.
Because the service transport handle
SVCXPRT contains a single data area
for decoding arguments and encoding results, the structure cannot freely
be shared between threads that call functions to decode arguments and
encode results. When a server is operating in the Automatic or User MT
modes, however, a copy of this structure is passed to the service
dispatch procedure in order to enable concurrent request processing.
Under these circumstances, some routines which would otherwise be Unsafe,
become Safe. These are marked as such. Also marked are routines that are
Unsafe for multithreaded applications, and are not to be used by such
applications. See
rpc(3NSL) for the definition of the
SVCXPRT data
structure.
The
svc_dg_enablecache() function allocates a duplicate request cache for
the service endpoint
xprt, large enough to hold
cache_size entries. Once
enabled, there is no way to disable caching. The function returns
1 if
space necessary for a cache of the given size was successfully allocated,
and
0 otherwise. This function is Safe in multithreaded applications.
The
svc_done() function frees resources allocated to service a client
request directed to the service endpoint
xprt. This call pertains only to
servers executing in the User MT mode. In the User MT mode, service
procedures must invoke this call before returning, either after a client
request has been serviced, or after an error or abnormal condition that
prevents a reply from being sent. After
svc_done() is invoked, the
service endpoint
xprt should not be referenced by the service procedure.
Server multithreading modes and parameters can be set using the
rpc_control() call. This function is Safe in multithreaded applications.
It will have no effect if invoked in modes other than the User MT mode.
The
svc_exit() function when called by any of the RPC server procedures
or otherwise, destroys all services registered by the server and causes
svc_run() to return. If RPC server activity is to be resumed, services
must be reregistered with the RPC library through one of the
rpc_svc_reg(3NSL) functions. The
svc_exit() function has global scope and
ends all RPC server activity.
The
svc_freeargs() function macro frees any data allocated by the
RPC/XDR system when it decoded the arguments to a service procedure using
svc_getargs(). This routine returns
TRUE if the results were successfully
freed, and
FALSE otherwise. This function macro is Safe in multithreaded
applications utilizing the Automatic or User MT modes.
The
svc_getargs() function macro decodes the arguments of an
RPC request
associated with the
RPC service transport handle
xprt. The parameter
in is the address where the arguments will be placed;
inproc is the
XDR routine used to decode the arguments. This routine returns
TRUE if
decoding succeeds, and
FALSE otherwise. This function macro is Safe in
multithreaded applications utilizing the Automatic or User MT modes.
The
svc_getreq_common() function is called to handle a request on a file
descriptor.
The
svc_getreq_poll() function is only of interest if a service
implementor does not call
svc_run(), but instead implements custom
asynchronous event processing. It is called when
poll(2) has determined
that an RPC request has arrived on some RPC file descriptors;
pollretval is the return value from
poll(2) and
pfdp is the array of
pollfd structures on which the
poll(2) was done. It is assumed to be an array
large enough to contain the maximal number of descriptors allowed. The
svc_getreq_poll() function macro is Unsafe in multithreaded applications.
The
svc_getreqset() function is only of interest if a service implementor
does not call
svc_run(), but instead implements custom asynchronous event
processing. It is called when
select(3C) has determined that an
RPC request has arrived on some
RPC file descriptors;
rdfds is the resultant
read file descriptor bit mask. The routine returns when all file
descriptors associated with the value of
rdfds have been serviced. This
function macro is Unsafe in multithreaded applications.
The
svc_getrpccaller() function macro is the approved way of getting the
network address of the caller of a procedure associated with the
RPC service transport handle
xprt. The returned pointer to struct netbuf
shouldn't be deallocated by the svc_getrpccaller() caller. This function
macro is Safe in multithreaded applications.
In single-threaded mode, the
svc_run() function waits for
RPC requests to
arrive. When an RPC request arrives, the
svc_run() function calls the
appropriate service procedure. This procedure is usually waiting for the
poll(2) library call to return.
Applications that execute in the Automatic or the User MT mode should
invoke the
svc_run() function exactly once. In the Automatic MT mode, the
svc_run() function creates threads to service client requests. In the
User MT mode, the function provides a framework for service developers to
create and manage their own threads for servicing client requests.
The
svc_fdset global variable reflects the
RPC server's read file
descriptor bit mask. This is only of interest if service implementors do
not call
svc_run(), but rather do their own asynchronous event
processing. This variable is read-only may change after calls to
svc_getreqset() or after any creation routine. Do not pass its address to
select(3C). Instead, pass the address of a copy. Multithreaded
applications executing in either the Automatic MT mode or the User MT
mode should never read this variable. They should use auxiliary threads
to do asynchronous event processing. The
svc_fdset variable is limited to
1024 file descriptors and is considered obsolete. Use of
svc_pollfd is
recommended instead.
The
svc_pollfd global variable points to an array of
pollfd_t structures
that reflect the
RPC server's read file descriptor array. This is only of
interest if service implementors do not call
svc_run() but rather do
their own asynchronous event processing. This variable is read-only, and
it may change after calls to
svc_getreg_poll() or any creation routines.
Do no pass its address to
poll(2). Instead, pass the address of a copy.
By default,
svc_pollfd is limited to 1024 entries. Use
rpc_control(3NSL) to remove this limitation. Multithreaded applications executing in either
the Automatic MT mode or the User MT mode should never be read this
variable. They should use auxiliary threads to do asynchronous event
processing.
The
svc_max_pollfd global variable contains the maximum length of the
svc_pollfd array. This variable is read-only, and it may change after
calls to
svc_getreg_poll() or any creation routines.
The
svc_sendreply() function is called by an
RPC service dispatch routine
to send the results of a remote procedure call. The
xprt parameter is the
transport handle of the request. The
outproc parameter is the
XDR routine
used to encode the results. The
out parameter is the address of the
results. This routine returns
TRUE if it succeeds,
FALSE otherwise. The
svc_sendreply() function macro is Safe in multithreaded applications that
use the Automatic or the User MT mode.
The
svc_fd_negotiate_ucred() function is called by an RPC server to
inform the underlying transport that the function wishes to receive
ucreds for local calls, including those over IP transports.
The
svc_getcallerucred() function attempts to retrieve the
ucred_t associated with the caller. The function returns 0 when successful and
-1 when not.
When successful, the
svc_getcallerucred() function stores the pointer to
a freshly allocated
ucred_t in the memory location pointed to by the
ucred argument if that memory location contains the null pointer. If the
memory location is non-null, the function reuses the existing
ucred_t.
When
ucred is no longer needed, a credential allocated by
svc_getcallerucred() should be freed with
ucred_free(3C).
ATTRIBUTES
See
attributes(7) for descriptions of attribute types and values.
+---------------+-----------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-----------------+
|MT-Level | See below. |
+---------------+-----------------+
The
svc_fd_negotiate_ucred(),
svc_dg_enablecache(),
svc_getrpccaller(),
and
svc_getcallerucred() functions are Safe in multithreaded
applications. The
svc_freeargs(),
svc_getargs(), and
svc_sendreply() functions are Safe in multithreaded applications that use the Automatic
or the User MT mode. The
svc_getreq_common(),
svc_getreqset(), and
svc_getreq_poll() functions are Unsafe in multithreaded applications and
should be called only from the main thread.
SEE ALSO
rpcgen(1),
poll(2),
getpeerucred(3C),
select(3C),
ucred_free(3C),
rpc(3NSL),
rpc_control(3NSL),
rpc_svc_create(3NSL),
rpc_svc_err(3NSL),
rpc_svc_reg(3NSL),
attributes(7) November 24, 2014
RPC_SVC_CALLS(3NSL)