RPC(3N) RPC(3N)
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 rpcsecure(3N). Secure RPC can be used only if DES
encryption is available.
##include <>
void
authdestroy(auth)
AUTH **auth;;
A macro that destroys the authentication information associated
with auth. Destruction usually involves deallocation of private
data structures. The use of auth is undefined after calling
authdestroy().
AUTH **
authnonecreate()
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 **
authunixcreate(host,, uid,, gid,, len,, aupgids)
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
aupgids refer to a counted array of groups to which the user
belongs. It is easy to impersonate a user.
AUTH **
authunixcreatedefault()
Calls authunixcreate() with the appropriate parameters.
callrpc(host,, prognum,, versnum,, procnum,, inproc,, in,, outproc,, out)
char **host;;
ulong prognum,, versnum,, procnum;;
char **in,, **out;;
xdrproct 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 procedure's
parameters, and outproc is used to decode the procedure's
results. This routine returns zero if it succeeds, or the value
of enum clntstat cast to an integer if it fails. The routine
clntperrno() is handy for translating failure statuses into
messages.
Warning: calling remote procedures with this routine uses UDP/IP
as a transport; see clntudpcreate() for restrictions. You do
not have control of timeouts or authentication using this rou-
tine.
enum clntstat
clntbroadcast(prognum,, versnum,, procnum,, inproc,, in,, outproc,, out,, eachresult)
ulong prognum,, versnum,, procnum;;
char **in,, **out;;
xdrproct inproc,, outproc;;
resultproct 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 sockaddrin **addr;;
where out is the same as out passed to clntbroadcast(), except
that the remote procedure's output is decoded there; addr points
to the address of the machine that sent the results. If eachre-
sult() returns zero, clntbroadcast() 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 clntstat
clntcall(clnt,, procnum,, inproc,, in,, outproc,, out,, tout)
CLIENT **clnt;;
ulong
procnum;;
xdrproct 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 clntcreate(). 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 proce-
dure's results; tout is the time allowed for results to come
back.
clntdestroy(clnt)
CLIENT **clnt;;
A macro that destroys the client's RPC handle. Destruction usu-
ally involves deallocation of private data structures, including
clnt itself. Use of clnt is undefined after calling
clntdestroy(). If the RPC library opened the associated
socket, it will close it also. Otherwise, the socket remains
open.
CLIENT **
clntcreate(host,, prog,, vers,, proto)
char **host;;
ulong 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 supported
values for this field are "udp" and "tcp". Default timeouts are
set, but can be modified using clntcontrol().
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.
boolt
clntcontrol(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:
CLSETIMEOUT struct timeval set total timeout
CLGETIMEOUT struct timeval get total timeout
Note: if you set the timeout using clntcontrol(), the timeout
parameter passed to clntcall() will be ignored in all future
calls.
CLGETSERVERADR struct sockaddrin get server's address
The following operations are valid for UDP only:
CLSETRETRYTIMEOUT struct timeval set the retry timeout
CLGETRETRYTIMEOUT 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.
clntfreeres(clnt,, outproc,, out)
CLIENT **clnt;;
xdrproct 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 describ-
ing the results. This routine returns one if the results were
successfully freed, and zero otherwise.
void
clntgeterr(clnt,, errp)
CLIENT **clnt;;
struct rpcerr **errp;;
A macro that copies the error structure out of the client handle
to the structure at address errp.
void
clntpcreateerror(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 clntcreate(), clntrawcre-
ate(), clnttcpcreate(), or clntudpcreate() call fails.
void
clntperrno(stat)
enum clntstat stat;;
Print a message to standard error corresponding to the condition
indicated by stat. Used after callrpc().
clntperror(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 clntcall().
char **
clntspcreateerror
char **s;;
Like clntpcreateerror(), 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 **
clntsperrno(stat)
enum clntstat stat;;
Take the same arguments as clntperrno(), but instead of sending
a message to the standard error indicating why an RPC call
failed, return a pointer to a string which contains the message.
The string ends with a NEWLINE.
clntsperrno() is used instead of clntperrno() 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 format dif-
ferent than that supported by clntperrno() is to be used.
Note: unlike clntsperror() and clntspcreaterror(), clntsper-
rno() returns pointer to static data, but the result will not
get overwritten on each call.
char **
clntsperror(rpch,, s)
CLIENT **rpch;;
char **s;;
Like clntperror(), except that (like clntsperrno()) it returns
a string instead of printing to standard error.
Bugs: returns pointer to static data that is overwritten on each
call.
CLIENT **
clntrawcreate(prognum,, versnum)
ulong 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 svcrawcreate(). This allows simulation of
RPC and acquisition of RPC overheads, such as round trip times,
without any kernel interference. This routine returns NUL if it
fails.
CLIENT **
clnttcpcreate(addr,, prognum,, versnum,, sockp,, sendsz,, recvsz)
struct sockaddrin **addr;;
ulong prognum,, versnum;;
int **sockp;;
uint sendsz,, recvsz;;
This routine creates an RPC client for the remote program
prognum, version versnum; the client uses TCP/IP as a transport.
The remote program is located at Internet address *addr. If
addr->>sinport 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 RPCANYSOCK, 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 NUL if it fails.
CLIENT **
clntudpcreate(addr,, prognum,, versnum,, wait,, sockp)
struct sockaddrin **addr;;
ulong 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 trans-
port. The remote program is located at Internet address addr.
If addr->>sinport 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 RPCANYSOCK, 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 clntcall().
Warning: since UDP-based RPC messages can only hold up to 8
Kbytes of encoded data, this transport cannot be used for proce-
dures that take large arguments or return huge results.
CLIENT **
clntudpbufcreate(addr,, prognum,, versnum,, wait,, sockp,, sendsize,, recosize)
struct sockaddrin **addr;;
ulong 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->>sinport 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 RPCANYSOCK, 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 clntcall().
This allows the user to specify the maximun packet size for
sending and receiving UDP-based RPC messages.
int
getmyaddress(addr)
struct sockaddrin **addr;;
Stuff the machine's IP address into *addr, without consulting
the library routines that deal with /etc/hosts. The port number
is always set to htons(PMAPORT). Returns zero on success, non-
zero on failure.
struct pmaplist **
pmapgetmaps(addr)
struct sockaddrin **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 NUL . The command
`rpcinfo -p' uses this routine.
ushort
pmapgetport(addr,, prognum,, versnum,, protocol)
struct sockaddrin **addr;;
ulong 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
IPROTOUDP or IPROTOTCP. A return value of zero means that
the mapping does not exist or that the RPC system failured to
contact the remote portmap service. In the latter case, the
global variable rpccreateerr() contains the RPC status.
enum clntstat
pmaprmtcall(addr,, prognum,, versnum,, procnum,, inproc,, in,, outproc,, out,, tout,, portp)
struct sockaddrin **addr;;
ulong prognum,, versnum,, procnum;;
char **in,, **out;;
xdrproct inproc,, outproc;;
struct timeval tout;;
ulong **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 suc-
ceeds. The definitions of other parameters are discussed in
callrpc() and clntcall(). This procedure should be used for a
"ping" and nothing else. See also clntbroadcast().
pmapset(prognum,, versnum,, protocol,, port)
ulong prognum,, versnum,, protocol;;
ushort 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 IPROTOUDP or IPROTOTCP. This routine returns one if
it succeeds, zero otherwise. Automatically done by svcregis-
ter().
pmapunset(prognum,, versnum)
ulong prognum,, versnum;;
A user interface to the portmap service, which destroys all map-
ping 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)
ulong prognum,, versnum,, procnum;;
char **(**procname) () ;;
xdrproct inproc,, outproc;;
Register procedure procname with the RPC service package. If a
request arrives for program prognum, version versnum, and proce-
dure procnum, procname is called with a pointer to its parame-
ter(s); progname should return a pointer to its static
result(s); inproc is used to decode the parameters while outproc
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 svcudpcreate() for restric-
tions.
struct rpccreateerr rpccreateerr;;
A global variable whose value is set by any RPC client creation
routine that does not succeed. Use the routine clntpcreateer-
ror() to print the reason why.
svcdestroy(xprt)
SVCXPRT **
xprt;;
A macro that destroys the RPC service transport handle, xprt.
Destruction usually involves deallocation of private data struc-
tures, including xprt itself. Use of xprt is undefined after
calling this routine.
fdset svcfdset;;
A global variable reflecting the RPC service side's read file
descriptor bit mask. This is only of interest if service imple-
mentors do not call svcrun(), but rather do their own asynchro-
nous event processing. This variable is read-only, and it may
change after calls to svcgetreqset() or any creation routines.
Do not pass its address to select()! Instead, pass the address
of a copy.
As well, note that if the process has descriptor limits which
are extended beyond FDSETSIZE, this variable will only be
usable for the first FDSETSIZE descriptors.
int svcfds;;
Similar to svcfedset, but limited to 32 descriptors. This
interface is obsoleted by svcfdset.
svcfreeargs(xprt,, inproc,, in)
SVCXPRT **xprt;;
xdrproct 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
svcgetargs(). This routine returns 1 if the results were suc-
cessfully freed, and zero otherwise.
svcgetargs(xprt,, inproc,, in)
SVCXPRT **xprt;;
xdrproct 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 sockaddrin **
svcgetcaller(xprt)
SVCXPRT **xprt;;
The approved way of getting the network address of the caller of
a procedure associated with the RPC service transport handle,
xprt.
svcgetreqset(rdfds)
fdset **rdfds;;
This routine is only of interest if a service implementor does
not call svcrun(), 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.
svcgetreq(rdfds)
int rdfds;;
Similar to svcgetreqset(), but limited to 32 descriptors. This
interface is obsoleted by svcgetreqset().
svcregister(xprt,, prognum,, versnum,, dispatch,, protocol)
SVCXPRT **xprt;;
ulong prognum,, versnum;;
void (**dispatch) ();;
ulong 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->>xpport is established with the local portmap service
(generally protocol is zero, IPROTOUDP or IPROTOTCP ). The
procedure dispatch has the following form:
dispatch(request,, xprt)
struct svcreq **request;;
SVCXPRT **xprt;;
The svcregister() routine returns one if it succeeds, and zero
otherwise.
svcrun()
This routine never returns. It waits for RPC requests to arrive,
and calls the appropriate service procedure using svcgetreq()
when one arrives. This procedure is usually waiting for a
select() system call to return.
svcsendreply(xprt,, outproc,, out)
SVCXPRT **xprt;;
xdrproct 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 routine which is
used to encode the results; and out is the address of the
results. This routine returns one if it succeeds, zero other-
wise.
void
svcunregister(prognum,, versnum)
ulong prognum,, versnum;;
Remove all mapping of the double [prognum,versnum] to dispatch
routines, and of the triple [prognum,versnum,*] to port number.
void
svcerrauth(xprt,, why)
SVCXPRT **xprt;;
enum authstat why;;
Called by a service dispatch routine that refuses to perform a
remote procedure call due to an authentication error.
void
svcerrdecode(xprt)
SVCXPRT **xprt;;
Called by a service dispatch routine that cannot successfully
decode its parameters. See also svcgetargs().
void
svcerrnoproc(xprt)
SVCXPRT **xprt;;
Called by a service dispatch routine that does not implement the
procedure number that the caller requests.
void
svcerrnoprog(xprt)
SVCXPRT **xprt;;
Called when the desired program is not registered with the RPC
package. Service implementors usually do not need this routine.
void
svcerrprogvers(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
svcerrsystemerr(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
svcerrweakauth(xprt)
SVCXPRT **xprt;;
Called by a service dispatch routine that refuses to perform a
remote procedure call due to insufficient authentication parame-
ters. The routine calls svcerrauth(xprt,, AUTHTOWEAK).
SVCXPRT **
svcrawcreate()
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 clntrawcreate(). This rou-
tine allows simulation of RPC and acquisition of RPC overheads
(such as round trip times), without any kernel interference.
This routine returns NUL if it fails.
SVCXPRT **
svctcpcreate(sock,, sendbufsize,, recvbufsize)
int sock;;
uint sendbufsize,, recvbufsize;;
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 RPCANYSOCK, 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->>xpsock is the transport's socket descriptor,
and xprt->>xpport is the transport's port number. This routine
returns NUL 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 **
svcfdcreate(fd,, sendsize,, recvsize)
int fd;;
uint sendsize;;
uint 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 cho-
sen.
SVCXPRT **
svcudpbufcreate(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 RPCANYSOCK ,, 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 com-
pletion, xprt->>xpsock is the transport's socket descriptor, and
xprt->>xpport is the transport's port number. This routine
returns NUL if it fails.
This allows the user to specify the maximun packet size for
sending and receiving UDP-based RPC messages.
xdracceptedreply(xdrs,, ar)
XDR **xdrs;;
struct acceptedreply **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.
xdrauthunixparms(xdrs,, aupp)
XDR **xdrs;;
struct authunixparms **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
xdrcallhdr(xdrs,, chdr)
XDR **xdrs;;
struct rpcmsg **chdr;;
Used for describing RPC call header messages. This routine is
useful for users who wish to generate RPC-style messages without
using the RPC package.
xdrcallmsg(xdrs,, cmsg)
XDR **xdrs;;
struct rpcmsg **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.
xdropaqueauth(xdrs,, ap)
XDR **xdrs;;
struct opaqueauth **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.
xdrpmap(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 gener-
ate these parameters without using the pmap interface.
xdrpmaplist(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.
xdrrejectedreply(xdrs,, rr)
XDR **xdrs;;
struct rejectedreply **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.
xdrreplymsg(xdrs,, rmsg)
XDR **xdrs;;
struct rpcmsg **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
xprtregister(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 svcfds(). Service implementors
usually do not need this routine.
void
xprtunregister(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 svcfds(). Service implementors
usually do not need this routine.
SEE ALSO
rpcsecure(3N), xdr(3N)
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.
16 February 1988 RPC(3N)
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