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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 private data structures. The
use of auth is undefined after calling 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 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 clnt_stat cast to an integer if it fails. The routine clnt_perrno()
is handy for translating failure statuses 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 usually involves
deallocation of private data structures, including 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 supported values for this field are lqudprq
and lqtcprq. 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 arguments 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 supported values of req and their argument types
and what they do are:
CLSET_TIMEOUT struct timeval set total timeoutCLGET_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 timeoutCLGET_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
- handle 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_create(), clnttcp_create(), or clntudp_create()
call fails.
void
clnt_perrno(stat)
enum clnt_stat stat;
- Print a message to standard error corresponding
- to the condition 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 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
.
- 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 format 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 transport. 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 procedures 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 number 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 command `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 lqpingrq 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_register().
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 succeeds, 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 procedure procnum, procname
is called with a pointer to its parameter(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 svcudp_create()
for restrictions.
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_pcreateerror() 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 successfully 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 handle, 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 procedure, dispatch.
If protocol is zero, the service is not registered 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 waiting 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
routine which is used to encode the results;
and out is the address of the results. This routine returns one if it succeeds,
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 routine.
void
svcerr_weakauth(xprt)
SVCXPRT *xprt;
- Called by a service dispatch routine that refuses to perform
- a remote procedure
call due to insufficient authentication parameters. 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
overheads (such as round trip times), without any kernel interference.
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 without 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 generate 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 parameters 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
.
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