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 pro‐
grams to make procedure calls on other machines across the network.
These routines are associated with the server side of the RPC mecha‐
nism. 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 argu‐
ments 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 pro‐
cessing. Under these circumstances, some routines which would other‐
wise 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 condi‐
tion that prevents a reply from being sent. After svc_done() is
invoked, the service endpoint xprt should not be referenced by the ser‐
vice 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 either through one of the
rpc_svc_create(3NSL) functions, or using xprt_register(3NSL). 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 suc‐
cessfully 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 imple‐
mentor does not call svc_run(), but instead implements custom asynchro‐
nous 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 applica‐
tions.
The svc_getreqset() function is only of interest if a service implemen‐
tor 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 is the approved way of getting the net‐
work address of the caller of a procedure associated with the RPC ser‐
vice transport handle xprt. This function macro is Safe in multi‐
threaded applications.
The svc_run() function never returns. In single-threaded mode, the
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 devel‐
opers 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 pro‐
cessing. 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 struc‐
tures that reflect the RPC server's read file descriptor array. This is
only of interest if service 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 appli‐
cations 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 rou‐
tine 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(5) 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 applica‐
tions. 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 ALSOrpcgen(1), poll(2), getpeerucred(3C), rpc(3NSL), rpc_control(3NSL),
rpc_svc_create(3NSL), rpc_svc_err(3NSL), rpc_svc_reg(3NSL), select(3C),
ucred_free(3C), xprt_register(3NSL), attributes(5)SunOS 5.10 26 Jan 2004 rpc_svc_calls(3NSL)
