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NAMErpc_svc_calls: svc_dg_enablecache(), svc_done(), svc_exit(), svc_fd_negotiate_ucred(), svc_fdset(), svc_freeargs(), svc_getargs(), svc_getreq_common(), svc_getreq_poll(), svc_getreqset(), svc_getrpccaller(), svc_pollset(), svc_run(), svc_sendreply() — library routines for RPC servers SYNOPSIS#include <rpc/rpc.h>
int svc_dg_enablecache(SVCXPRT *xprt,
const u_int 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 xdrproc_t inproc,
caddr_t in);
bool_t svc_getargs(const SVCXPRT *xprt,
const xdrproc_t inproc,
caddr_t in);
void svc_getreq_common(const int fd);
void svc_getreq_poll(struct pollfd *pfdp,
const int pollretval);
void svc_getreqset(fd_set *rdfds);
struct netbuf *svc_getrpccaller(const SVCXPRT *xprt);
void svc_run(void);
bool_t svc_sendreply(const SVCXPRT *xprt,
const xdrproc_t outproc,
const caddr_t out);
fd_set svc_fdset;
pollfd_t *svc_pollfd;
int svc_max_pollfd; DESCRIPTIONThese 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. The HP-UX implementation of RPC only supports the X/Open Transport
Interface (XTI).
Applications that are written using the Transport Layer Interface
(TLI) and wish to use RPC, must convert their application to XTI. Multithread ConsiderationsBecause 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 (see
rpc_control(3N)),
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 thread-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. RoutinesSee
rpc(3N)
for the definition of the
SVCXPRT
data structure.
- int svc_dg_enablecache()
This 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.
This routine 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. - int svc_done()
This 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. - void svc_exit()
This 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()
functions, or using
xprt_register(). svc_exit()
has global scope and ends all RPC server activity. - bool_t svc_freeargs()
A function macro that 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. - bool_t svc_getargs()
A function macro that 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. - void svc_getreq_common()
This function is called to handle a request on the given
file descriptor. This function is unsafe in multithreaded applications. - void svc_getreq_poll()
This 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()
has determined that an RPC request has arrived on some RPC
file descriptors;
pollretval
is the return value from
poll()
and
pfdp
is the array of
pollfd
structures on which the
poll()
was done.
It is assumed to be an array large enough to
contain the maximal number of descriptors allowed. This function is unsafe in multithreaded applications. - void svc_getreqset()
This routine 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()
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 is unsafe in multithreaded applications. - struct netbuf *svc_getrpccaller()
This function is the approved way of getting the network address of
the caller of a procedure associated with the RPC
service transport handle
xprt. This function macro is safe in multithreaded applications. - void svc_run()
This function never returns.
In single-threaded mode, it 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()
library call to return. Applications executing in the Automatic or User MT modes should invoke
the
svc_run()
function exactly once.
In the Automatic MT mode, the 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. - bool_t svc_sendreply()
This 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 which is used to encode the results.
The
out
parameter is the address of the results.
This routine returns
TRUE
if it succeeds,
FALSE
otherwise. This function is safe in multithreaded applications utilizing the
Automatic or User MT modes. - void svc_fd_negotiate_ucred()
This 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. - fd_set svc_fdset
A global variable reflecting 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, and it may change after calls to
svc_getreqset()
or any creation routines.
Do not pass its address to
select().
Instead, pass the address of a copy. Multithreaded applications executing in either the Automatic or the
User MT modes 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. - pollfd_t *svc_pollfd
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 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().
Instead, pass the address of a copy.
By default,
svc_pollfd
is limited to 1024 entries.
Use
rpc_control()
to remove this limitation. Multithreaded applications executing in either the Automatic or the
User MT mode should never read this variable.
They should use auxiliary threads to do asynchronous event processing. - int svc_max_pollfd
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.
MULTITHREAD USAGE- Thread Safe:
See
Notes
below. - Cancel Safe:
See
Notes
below. - Fork Safe:
No - Async-cancel Safe:
No - Async-signal Safe:
No
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 supports asynchronous cancellation or asynchronous signals. Notessvc_dg_enablecache()
and
svc_getrpccaller()
are Thread Safe and Cancel Safe in multithreaded applications.
svc_freeargs(),
svc_getargs(),
and
svc_sendreply()
are Thread Safe and Cancel Safe in multithreaded applications that use
the Automatic or the User MT modes.
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. |
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