xprt_unregister
RPC(3) RPC(3)
NAME
rpc - library routines for remote procedure calls
SYNOPSIS AND DESCRIPTION
These routines allow C programs to make procedure calls on other
machines across the network. First, the client calls a procedure to
send a data packet to the server. Upon receipt of the packet, the
server calls a dispatch routine to perform the requested service, and
then sends back a reply. Finally, the procedure call returns to the
client.
Routines that are used for Secure RPC (DES authentication) are
described in rpc_secure(3). Secure RPC can be used only if DES
encryption is available.
#include <rpc/rpc.h>
void
auth_destroy(auth)
AUTH *auth;
A macro that destroys the authentication information associated
with auth. Destruction usually involves deallocation of pri-
vate data structures. The use of auth is undefined after call-
ing auth_destroy().
AUTH *
authnone_create()
Create and returns an RPC authentication handle that passes
nonusable authentication information with each remote procedure
call. This is the default authentication used by RPC.
AUTH *
authunix_create(host, uid, gid, len, aup_gids)
char *host;
int uid, gid, len, *aup.gids;
Create and return an RPC authentication handle that contains
authentication information. The parameter host is the name of
the machine on which the information was created; uid is the
user’s user ID ; gid is the user’s current group ID ; len and
aup_gids refer to a counted array of groups to which the user
belongs. It is easy to impersonate a user.
AUTH *
authunix_create_default()
Calls authunix_create() with the appropriate parameters.
callrpc(host, prognum, versnum, procnum, inproc, in, outproc, out)
char *host;
u_long prognum, versnum, procnum;
char *in, *out;
xdrproc_t inproc, outproc;
Call the remote procedure associated with prognum, versnum, and
procnum on the machine, host. The parameter in is the address
of the procedure’s argument(s), and out is the address of where
to place the result(s); inproc is used to encode the proce-
dure’s parameters, and outproc is used to decode the proce-
dure’s results. This routine returns zero if it succeeds, or
the value of enum clnt_stat cast to an integer if it fails.
The routine clnt_perrno() is handy for translating failure sta-
tuses into messages.
Warning: calling remote procedures with this routine uses
UDP/IP as a transport; see clntudp_create() for restrictions.
You do not have control of timeouts or authentication using
this routine.
enum clnt_stat
clnt_broadcast(prognum, versnum, procnum, inproc, in, outproc, out, eachresult)
u_long prognum, versnum, procnum;
char *in, *out;
xdrproc_t inproc, outproc;
resultproc_t eachresult;
Like callrpc(), except the call message is broadcast to all
locally connected broadcast nets. Each time it receives a
response, this routine calls eachresult(), whose form is:
eachresult(out, addr)
char *out;
struct sockaddr_in *addr;
where out is the same as out passed to clnt_broadcast(), except
that the remote procedure’s output is decoded there; addr
points to the address of the machine that sent the results. If
eachresult() returns zero, clnt_broadcast() waits for more
replies; otherwise it returns with appropriate status.
Warning: broadcast sockets are limited in size to the maximum
transfer unit of the data link. For ethernet, this value is
1500 bytes.
enum clnt_stat
clnt_call(clnt, procnum, inproc, in, outproc, out, tout)
CLIENT *clnt;
u_long
procnum;
xdrproc_t inproc, outproc;
char *in, *out;
struct timeval tout;
A macro that calls the remote procedure procnum associated with
the client handle, clnt, which is obtained with an RPC client
creation routine such as clnt_create(). The parameter in is
the address of the procedure’s argument(s), and out is the
address of where to place the result(s); inproc is used to
encode the procedure’s parameters, and outproc is used to
decode the procedure’s results; tout is the time allowed for
results to come back.
clnt_destroy(clnt)
CLIENT *clnt;
A macro that destroys the client’s RPC handle. Destruction usu-
ally involves deallocation of private data structures, includ-
ing clnt itself. Use of clnt is undefined after calling
clnt_destroy(). If the RPC library opened the associated
socket, it will close it also. Otherwise, the socket remains
open.
CLIENT *
clnt_create(host, prog, vers, proto)
char *host;
u_long prog, vers;
char *proto;
Generic client creation routine. host identifies the name of
the remote host where the server is located. proto indicates
which kind of transport protocol to use. The currently sup-
ported values for this field are “udp” and “tcp”. Default
timeouts are set, but can be modified using clnt_control().
Warning: Using UDP has its shortcomings. Since UDP-based RPC
messages can only hold up to 8 Kbytes of encoded data, this
transport cannot be used for procedures that take large argu-
ments or return huge results.
bool_t
clnt_control(cl, req, info)
CLIENT *cl;
char *info;
A macro used 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 UDP and TCP, the sup-
ported 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
parameter passed to clnt_call() will be ignored in all future
calls.
CLGET_SERVER_ADDR struct sockaddr_in get server’s address
The following operations are valid for UDP 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 UDP RPC waits for the server
to reply before retransmitting the request.
clnt_freeres(clnt, outproc, out)
CLIENT *clnt;
xdrproc_t outproc;
char *out;
A macro that frees any data allocated by the RPC/XDR system
when it decoded the results of an RPC call. The parameter out
is the address of the results, and outproc is the XDR routine
describing the results. This routine returns one if the
results were successfully freed, and zero otherwise.
void
clnt_geterr(clnt, errp)
CLIENT *clnt;
struct rpc_err *errp;
A macro that copies the error structure out of the client han-
dle to the structure at address errp.
void
clnt_pcreateerror(s)
char *s;
Print a message to standard error indicating why a client RPC
handle could not be created. The message is prepended with
string s and a colon. Used when a clnt_create(), clntraw_cre-
ate(), clnttcp_create(), or clntudp_create() call fails.
void
clnt_perrno(stat)
enum clnt_stat stat;
Print a message to standard error corresponding to the condi-
tion indicated by stat. Used after callrpc().
clnt_perror(clnt, s)
CLIENT *clnt;
char *s;
Print a message to standard error indicating why an RPC call
failed; clnt is the handle used to do the call. The message is
prepended with string s and a colon. Used after clnt_call().
char *
clnt_spcreateerror
char *s;
Like clnt_pcreateerror(), except that it returns a string
instead of printing to the standard error.
Bugs: returns pointer to static data that is overwritten on
each call.
char *
clnt_sperrno(stat)
enum clnt_stat stat;
Take the same arguments as clnt_perrno(), but instead of send-
ing a message to the standard error indicating why an RPC call
failed, return a pointer to a string which contains the mes-
sage. The string ends with a NEWLINE.
clnt_sperrno() is used instead of clnt_perrno() if the program
does not have a standard error (as a program running as a
server quite likely does not), or if the programmer does not
want the message to be output with printf, or if a message for-
mat different than that supported by clnt_perrno() is to be
used. Note: unlike clnt_sperror() and clnt_spcreaterror(),
clnt_sperrno() returns pointer to static data, but the result
will not get overwritten on each call.
char *
clnt_sperror(rpch, s)
CLIENT *rpch;
char *s;
Like clnt_perror(), except that (like clnt_sperrno()) it
returns a string instead of printing to standard error.
Bugs: returns pointer to static data that is overwritten on
each call.
CLIENT *
clntraw_create(prognum, versnum)
u_long prognum, versnum;
This routine creates a toy RPC client for the remote program
prognum, version versnum. The transport used to pass messages
to the service is actually a buffer within the process’s
address space, so the corresponding RPC server should live in
the same address space; see svcraw_create(). This allows
simulation of RPC and acquisition of RPC overheads, such as
round trip times, without any kernel interference. This routine
returns NULL if it fails.
CLIENT *
clnttcp_create(addr, prognum, versnum, sockp, sendsz, recvsz)
struct sockaddr_in *addr;
u_long prognum, versnum;
int *sockp;
u_int sendsz, recvsz;
This routine creates an RPC client for the remote program
prognum, version versnum; the client uses TCP/IP as a trans-
port. The remote program is located at Internet address *addr.
If addr->sin_port is zero, then it is set to the actual port
that the remote program is listening on (the remote portmap
service is consulted for this information). The parameter sockp
is a socket; if it is RPC_ANYSOCK, then this routine opens a
new one and sets sockp. Since TCP-based RPC uses buffered I/O
, the user may specify the size of the send and receive buffers
with the parameters sendsz and recvsz; values of zero choose
suitable defaults. This routine returns NULL if it fails.
CLIENT *
clntudp_create(addr, prognum, versnum, wait, sockp)
struct sockaddr_in *addr;
u_long prognum, versnum;
struct timeval wait;
int *sockp;
This routine creates an RPC client for the remote program
prognum, version versnum; the client uses use UDP/IP as a
transport. The remote program is located at Internet address
addr. If addr->sin_port is zero, then it is set to actual port
that the remote program is listening on (the remote portmap
service is consulted for this information). The parameter sockp
is a socket; if it is RPC_ANYSOCK, then this routine opens a
new one and sets sockp. The UDP transport resends the call
message in intervals of wait time 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().
Warning: since UDP-based RPC messages can only hold up to 8
Kbytes of encoded data, this transport cannot be used for pro-
cedures that take large arguments or return huge results.
CLIENT *
clntudp_bufcreate(addr, prognum, versnum, wait, sockp, sendsize, recosize)
struct sockaddr_in *addr;
u_long prognum, versnum;
struct timeval wait;
int *sockp;
unsigned int sendsize;
unsigned int recosize;
This routine creates an RPC client for the remote program
prognum, on versnum; the client uses use UDP/IP as a transport.
The remote program is located at Internet address addr. If
addr->sin_port is zero, then it is set to actual port that the
remote program is listening on (the remote portmap service is
consulted for this information). The parameter sockp is a
socket; if it is RPC_ANYSOCK, then this routine opens a new one
and sets sockp. The UDP transport resends the call message in
intervals of wait time 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().
This allows the user to specify the maximum packet size for
sending and receiving UDP-based RPC messages.
void
get_myaddress(addr)
struct sockaddr_in *addr;
Stuff the machine’s IP address into *addr, without consulting
the library routines that deal with /etc/hosts. The port num-
ber is always set to htons(PMAPPORT).
struct pmaplist *
pmap_getmaps(addr)
struct sockaddr_in *addr;
A user interface to the portmap service, which returns a list
of the current RPC program-to-port mappings on the host located
at IP address *addr. This routine can return NULL . The com-
mand ‘rpcinfo -p’ uses this routine.
u_short
pmap_getport(addr, prognum, versnum, protocol)
struct sockaddr_in *addr;
u_long prognum, versnum, protocol;
A user interface to the portmap service, which returns the port
number on which waits a service that supports program number
prognum, version versnum, and speaks the transport protocol
associated with protocol. The value of protocol is most likely
IPPROTO_UDP or IPPROTO_TCP. A return value of zero means that
the mapping does not exist or that the RPC system failed to
contact the remote portmap service. In the latter case, the
global variable rpc_createerr() contains the RPC status.
enum clnt_stat
pmap_rmtcall(addr, prognum, versnum, procnum, inproc, in, outproc, out, tout, portp)
struct sockaddr_in *addr;
u_long prognum, versnum, procnum;
char *in, *out;
xdrproc_t inproc, outproc;
struct timeval tout;
u_long *portp;
A user interface to the portmap service, which instructs
portmap on the host at IP address *addr to make an RPC call on
your behalf to a procedure on that host. The parameter *portp
will be modified to the program’s port number if the procedure
succeeds. The definitions of other parameters are discussed in
callrpc() and clnt_call(). This procedure should be used for a
“ping” and nothing else. See also clnt_broadcast().
pmap_set(prognum, versnum, protocol, port)
u_long prognum, versnum, protocol;
u_short port;
A user interface to the portmap service, which establishes a
mapping between the triple [prognum,versnum,protocol] and port
on the machine’s portmap service. The value of protocol is most
likely IPPROTO_UDP or IPPROTO_TCP. This routine returns one if
it succeeds, zero otherwise. Automatically done by svc_regis-
ter().
pmap_unset(prognum, versnum)
u_long prognum, versnum;
A user interface to the portmap service, which destroys all
mapping between the triple [prognum,versnum,*] and ports on the
machine’s portmap service. This routine returns one if it suc-
ceeds, zero otherwise.
registerrpc(prognum, versnum, procnum, procname, inproc, outproc)
u_long prognum, versnum, procnum;
char *(*procname) () ;
xdrproc_t inproc, outproc;
Register procedure procname with the RPC service package. If a
request arrives for program prognum, version versnum, and pro-
cedure procnum, procname is called with a pointer to its param-
eter(s); progname should return a pointer to its static
result(s); inproc is used to decode the parameters while out-
proc is used to encode the results. This routine returns zero
if the registration succeeded, -1 otherwise.
Warning: remote procedures registered in this form are accessed
using the UDP/IP transport; see svcudp_create() for restric-
tions.
struct rpc_createerr rpc_createerr;
A global variable whose value is set by any RPC client creation
routine that does not succeed. Use the routine clnt_pcreateer-
ror() to print the reason why.
svc_destroy(xprt)
SVCXPRT *
xprt;
A macro that destroys the RPC service transport handle, xprt.
Destruction usually involves deallocation of private data
structures, including xprt itself. Use of xprt is undefined
after calling this routine.
fd_set svc_fdset;
A global variable reflecting the RPC service side’s read file
descriptor bit mask; it is suitable as a parameter to the
select system call. This is only of interest if a service
implementor does not call svc_run(), but rather does his own
asynchronous event processing. This variable is read-only (do
not pass its address to select!), yet it may change after calls
to svc_getreqset() or any creation routines.
int svc_fds;
Similar to svc_fdset, but limited to 32 descriptors. This
interface is obsoleted by svc_fdset.
svc_freeargs(xprt, inproc, in)
SVCXPRT *xprt;
xdrproc_t inproc;
char *in;
A 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 1 if the results were suc-
cessfully freed, and zero otherwise.
svc_getargs(xprt, inproc, in)
SVCXPRT *xprt;
xdrproc_t inproc;
char *in;
A 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 one if decoding succeeds, and zero otherwise.
struct sockaddr_in *
svc_getcaller(xprt)
SVCXPRT *xprt;
The approved way of getting the network address of the caller
of a procedure associated with the RPC service transport han-
dle, xprt.
svc_getreqset(rdfds)
fd_set *rdfds;
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 the select system call has
determined that an RPC request has arrived on some RPC
socket(s) ; rdfds is the resultant read file descriptor bit
mask. The routine returns when all sockets associated with the
value of rdfds have been serviced.
svc_getreq(rdfds)
int rdfds;
Similar to svc_getreqset(), but limited to 32 descriptors. This
interface is obsoleted by svc_getreqset().
svc_register(xprt, prognum, versnum, dispatch, protocol)
SVCXPRT *xprt;
u_long prognum, versnum;
void (*dispatch) ();
u_long protocol;
Associates prognum and versnum with the service dispatch proce-
dure, dispatch. If protocol is zero, the service is not regis-
tered with the portmap service. If protocol is non-zero, then
a mapping of the triple [prognum,versnum,protocol] to
xprt->xp_port is established with the local portmap service
(generally protocol is zero, IPPROTO_UDP or IPPROTO_TCP ). The
procedure dispatch has the following form:
dispatch(request, xprt)
struct svc_req *request;
SVCXPRT *xprt;
The svc_register() routine returns one if it succeeds, and zero
otherwise.
svc_run()
This routine never returns. It waits for RPC requests to
arrive, and calls the appropriate service procedure using
svc_getreq() when one arrives. This procedure is usually wait-
ing for a select() system call to return.
svc_sendreply(xprt, outproc, out)
SVCXPRT *xprt;
xdrproc_t outproc;
char *out;
Called by an RPC service’s dispatch routine to send the results
of a remote procedure call. The parameter xprt is the
request’s associated transport handle; outproc is the XDR rou-
tine which is used to encode the results; and out is the
address of the results. This routine returns one if it suc-
ceeds, zero otherwise.
void
svc_unregister(prognum, versnum)
u_long prognum, versnum;
Remove all mapping of the double [prognum,versnum] to dispatch
routines, and of the triple [prognum,versnum,*] to port number.
void
svcerr_auth(xprt, why)
SVCXPRT *xprt;
enum auth_stat why;
Called by a service dispatch routine that refuses to perform a
remote procedure call due to an authentication error.
void
svcerr_decode(xprt)
SVCXPRT *xprt;
Called by a service dispatch routine that cannot successfully
decode its parameters. See also svc_getargs().
void
svcerr_noproc(xprt)
SVCXPRT *xprt;
Called by a service dispatch routine that does not implement
the procedure number that the caller requests.
void
svcerr_noprog(xprt)
SVCXPRT *xprt;
Called when the desired program is not registered with the RPC
package. Service implementors usually do not need this routine.
void
svcerr_progvers(xprt)
SVCXPRT *xprt;
Called when the desired version of a program is not registered
with the RPC package. Service implementors usually do not need
this routine.
void
svcerr_systemerr(xprt)
SVCXPRT *xprt;
Called by a service dispatch routine when it detects a system
error not covered by any particular protocol. For example, if
a service can no longer allocate storage, it may call this rou-
tine.
void
svcerr_weakauth(xprt)
SVCXPRT *xprt;
Called by a service dispatch routine that refuses to perform a
remote procedure call due to insufficient authentication param-
eters. The routine calls svcerr_auth(xprt, AUTH_TOOWEAK).
SVCXPRT *
svcfd_create(fd, sendsize, recvsize)
int fd;
u_int sendsize;
u_int recvsize;
Create a service on top of any open descriptor. Typically, this
descriptor is a connected socket for a stream protocol such as
TCP. sendsize and recvsize indicate sizes for the send and
receive buffers. If they are zero, a reasonable default is
chosen.
SVCXPRT *
svcraw_create()
This routine creates a toy RPC service transport, to which it
returns a pointer. The transport is really a buffer within the
process’s address space, so the corresponding RPC client should
live in the same address space; see clntraw_create(). This
routine allows simulation of RPC and acquisition of RPC over-
heads (such as round trip times), without any kernel interfer-
ence. This routine returns NULL if it fails.
SVCXPRT *
svctcp_create(sock, send_buf_size, recv_buf_size)
int sock;
u_int send_buf_size, recv_buf_size;
This routine creates a TCP/IP-based RPC service transport, to
which it returns a pointer. The transport is associated with
the socket sock, which may be RPC_ANYSOCK, in which case a new
socket is created. If the socket is not bound to a local TCP
port, then this routine binds it to an arbitrary port. Upon
completion, xprt->xp_sock is the transport’s socket descriptor,
and xprt->xp_port is the transport’s port number. This routine
returns NULL if it fails. Since TCP-based RPC uses buffered I/O
, users may specify the size of buffers; values of zero choose
suitable defaults.
SVCXPRT *
svcudp_bufcreate(sock, sendsize, recosize)
int sock;
This routine creates a UDP/IP-based RPC service transport, to
which it returns a pointer. The transport is associated with
the socket sock, which may be RPC_ANYSOCK , in which case a new
socket is created. If the socket is not bound to a local UDP
port, then this routine binds it to an arbitrary port. Upon
completion, xprt->xp_sock is the transport’s socket descriptor,
and xprt->xp_port is the transport’s port number. This routine
returns NULL if it fails.
This allows the user to specify the maximum packet size for
sending and receiving UDP-based RPC messages.
SVCXPRT *
svcudp_create(sock)
int sock;
This call is equivalent to svcudp_bufcreate(sock,SZ,SZ) for
some default size SZ.
xdr_accepted_reply(xdrs, ar)
XDR *xdrs;
struct accepted_reply *ar;
Used for encoding RPC reply messages. This routine is useful
for users who wish to generate RPC-style messages without using
the RPC package.
xdr_authunix_parms(xdrs, aupp)
XDR *xdrs;
struct authunix_parms *aupp;
Used for describing UNIX credentials. This routine is useful
for users who wish to generate these credentials without using
the RPC authentication package.
void
xdr_callhdr(xdrs, chdr)
XDR *xdrs;
struct rpc_msg *chdr;
Used for describing RPC call header messages. This routine is
useful for users who wish to generate RPC-style messages with-
out using the RPC package.
xdr_callmsg(xdrs, cmsg)
XDR *xdrs;
struct rpc_msg *cmsg;
Used for describing RPC call messages. This routine is useful
for users who wish to generate RPC-style messages without using
the RPC package.
xdr_opaque_auth(xdrs, ap)
XDR *xdrs;
struct opaque_auth *ap;
Used for describing RPC authentication information messages.
This routine is useful for users who wish to generate RPC-style
messages without using the RPC package.
xdr_pmap(xdrs, regs)
XDR *xdrs;
struct pmap *regs;
Used for describing parameters to various portmap procedures,
externally. This routine is useful for users who wish to gen-
erate these parameters without using the pmap interface.
xdr_pmaplist(xdrs, rp)
XDR *xdrs;
struct pmaplist **rp;
Used for describing a list of port mappings, externally. This
routine is useful for users who wish to generate these parame-
ters without using the pmap interface.
xdr_rejected_reply(xdrs, rr)
XDR *xdrs;
struct rejected_reply *rr;
Used for describing RPC reply messages. This routine is useful
for users who wish to generate RPC-style messages without using
the RPC package.
xdr_replymsg(xdrs, rmsg)
XDR *xdrs;
struct rpc_msg *rmsg;
Used for describing RPC reply messages. This routine is useful
for users who wish to generate RPC style messages without using
the RPC package.
void
xprt_register(xprt)
SVCXPRT *xprt;
After RPC service transport handles are created, they should
register themselves with the RPC service package. This routine
modifies the global variable svc_fds(). Service implementors
usually do not need this routine.
void
xprt_unregister(xprt)
SVCXPRT *xprt;
Before an RPC service transport handle is destroyed, it should
unregister itself with the RPC service package. This routine
modifies the global variable svc_fds(). Service implementors
usually do not need this routine.
SEE ALSO
rpc_secure(3), xdr(3)
The following manuals:
Remote Procedure Calls: Protocol Specification
Remote Procedure Call Programming Guide
rpcgen Programming Guide
RPC: Remote Procedure Call Protocol Specification, RFC1050, Sun
Microsystems, Inc., USC-ISI.
1988-02-16 RPC(3)
