RPC_SOC(3) BSD Library Functions Manual RPC_SOC(3)
NAME
rpc_soc, auth_destroy, authnone_create, authunix_create, authunix_create_default, callrpc, clnt_broadcast, clnt_call, clnt_control,
clnt_create, clnt_destroy, clnt_freeres, clnt_geterr, clnt_pcreateerror, clnt_perrno, clnt_perror, clnt_spcreateerror, clnt_sperrno,
clnt_sperror, clntraw_create, clnttcp_create, clntudp_bufcreate, clntudp_create, clntunix_create, get_myaddress, pmap_getmaps, pmap_getport,
pmap_rmtcall, pmap_set, pmap_unset, registerrpc, rpc_createerr, svc_destroy, svc_fds, svc_fdset, svc_getargs, svc_getcaller, svc_getreq,
svc_getreqset, svc_register, svc_run, svc_sendreply, svc_unregister, svcerr_auth, svcerr_decode, svcerr_noproc, svcerr_noprog,
svcerr_progvers, svcerr_systemerr, svcerr_weakauth, svcfd_create, svcunixfd_create, svcraw_create, svcunix_create, xdr_accepted_reply,
xdr_authunix_parms, xdr_callhdr, xdr_callmsg, xdr_opaque_auth, xdr_pmap, xdr_pmaplist, xdr_rejected_reply, xdr_replymsg, xprt_register,
xprt_unregister -- library routines for remote procedure calls
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <rpc/rpc.h>
See DESCRIPTION for function declarations.
DESCRIPTION
The svc_*() and clnt_*() functions described in this page are the old, TS-RPC interface to the XDR and RPC library, and exist for backward
compatibility. The new interface is described in the pages referenced from rpc(3).
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.
void
auth_destroy(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 return 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(char *host, u_int uid, u_int gid, int len, u_int *aup_gids)
Create and return an RPC authentication handle that contains UNIX authentication information. The host argument 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 arguments.
int callrpc(char *host, u_long prognum, u_long versnum, u_long procnum, xdrproc_t inproc, void *in, xdrproc_t outproc, void *out)
Call the remote procedure associated with prognum, versnum, and procnum on the machine host. The in argument 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 arguments,
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(u_long prognum, u_long versnum, u_long procnum, xdrproc_t inproc, char *in, xdrproc_t outproc, char *out,
bool_t (*eachresult)(caddr_t, struct sockaddr_in *))
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:
bool_t eachresult(caddr_t 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(CLIENT *clnt, u_long procnum, xdrproc_t inproc, char *in, xdrproc_t outproc, char *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 cre-
ation routine such as clnt_create(). The in argument 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 arguments, and outproc is used to decode the procedure's results;
tout is the time allowed for results to come back.
void clnt_destroy(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(char *host, u_long prog, u_long vers, char *proto)
Generic client creation routine. The host argument identifies the name of the remote host where the server is located. The proto
argument 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 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(CLIENT *cl, u_int req, char *info)
A macro used to change or retrieve various information about a client object. The req argument 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 timeout
CLGET_TIMEOUT struct timeval get total timeout
Note: if you set the timeout using clnt_control(), the timeout argument 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.
bool_t clnt_freeres(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 out argument is the
address of the results, and outproc is the XDR routine describing the results. This routine returns one if the results were success-
fully freed, and zero otherwise.
void
clnt_geterr(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(char *s)
prints 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. A newline is appended at the end of the message. Used when a clnt_create(), clntraw_create(), clnttcp_create(), or
clntudp_create() call fails.
void
clnt_perrno(enum clnt_stat stat)
Print a message to standard error corresponding to the condition indicated by stat. A newline is appended at the end of the message.
Used after callrpc().
void clnt_perror(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. A newline is appended at the end of the message. 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(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 clnt_sperrno() function 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 dif-
ferent from that supported by clnt_perrno() is to be used.
Note: unlike clnt_sperror() and clnt_spcreateerror(), clnt_sperrno() returns pointer to static data, but the result will not get
overwritten on each call.
char *
clnt_sperror(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(u_long prognum, u_long 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(struct sockaddr_in *addr, u_long prognum, u_long versnum, int *sockp, u_int sendsz, u_int 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 rpcbind(8) service is consulted for this information). The sockp argument 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 sendsz and recvsz arguments; values of zero choose suitable defaults. This routine returns
NULL if it fails.
CLIENT *
clntudp_create(struct sockaddr_in *addr, u_long prognum, u_long versnum, struct timeval wait, int *sockp)
This routine creates an RPC client for the remote program prognum, version versnum; the client uses 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 rpcbind(8) service is consulted for this information). The sockp argument 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(struct sockaddr_in *addr, u_long prognum, u_long 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 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 rpcbind(8) service is consulted for this information). The sockp argument 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.
CLIENT *
clntunix_create(struct sockaddr_un *raddr, u_long prognum, u_long versnum, int *sockp, u_int sendsz, u_int recvsz)
This routine creates an RPC client for the local program prognum, version versnum; the client uses UNIX-domain sockets as a trans-
port. The local program is located at the *raddr. The sockp argument is a socket; if it is RPC_ANYSOCK, then this routine opens a
new one and sets sockp. Since UNIX-based RPC uses buffered I/O, the user may specify the size of the send and receive buffers with
the sendsz and recvsz arguments; values of zero choose suitable defaults. This routine returns NULL if it fails.
int
get_myaddress(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). Returns zero on success, non-zero on failure.
struct pmaplist *
pmap_getmaps(struct sockaddr_in *addr)
A user interface to the rpcbind(8) 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(struct sockaddr_in *addr, u_long prognum, u_long versnum, u_long protocol)
A user interface to the rpcbind(8) 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 rpcbind(8) service. In the latter case, the global variable rpc_createerr contains the RPC status.
enum clnt_stat
pmap_rmtcall(struct sockaddr_in *addr, u_long prognum, u_long versnum, u_long procnum, xdrproc_t inproc, char *in, xdrproc_t outproc,
char *out, struct timeval tout, u_long *portp)
A user interface to the rpcbind(8) service, which instructs rpcbind(8) on the host at IP address addr to make an RPC call on your
behalf to a procedure on that host. The portp argument will be modified to the program's port number if the procedure succeeds. The
definitions of other arguments are discussed in callrpc() and clnt_call(). This procedure should be used for a ``ping'' and nothing
else. See also clnt_broadcast().
bool_t pmap_set(u_long prognum, u_long versnum, u_long protocol, u_short port)
A user interface to the rpcbind(8) service, which establishes a mapping between the triple (prognum, versnum, protocol) and port on
the machine's rpcbind(8) 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().
bool_t pmap_unset(u_long prognum, u_long versnum)
A user interface to the rpcbind(8) service, which destroys all mapping between the triple (prognum, versnum, *) and ports on the
machine's rpcbind(8) service. This routine returns one if it succeeds, zero otherwise.
bool_t registerrpc(u_long prognum, u_long versnum, u_long procnum, char *(*procname)(void), xdrproc_t inproc, xdrproc_t 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 argument(s); progname should return a pointer to its static result(s); inproc is
used to decode the arguments 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.
bool_t svc_destroy(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 template argument to the
select(2) system call. This is only of interest if a service implementor does not call svc_run(), but rather does his own asynchro-
nous event processing. This variable is read-only (do not pass its address to select(2)!), yet it may change after calls to
svc_getreqset() or any creation routines. As well, note that if the process has descriptor limits which are extended beyond
FD_SETSIZE, this variable will only be usable for the first FD_SETSIZE descriptors.
int svc_fds;
Similar to svc_fdset, but limited to 32 descriptors. This interface is obsoleted by svc_fdset.
bool_t svc_freeargs(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.
bool_t svc_getargs(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 in argument 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(SVCXPRT *xprt)
The approved way of getting the network address of the caller of a procedure associated with the RPC service transport handle, xprt.
void svc_getreqset(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(2) 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.
void svc_getreq(int rdfds)
Similar to svc_getreqset(), but limited to 32 descriptors. This interface is obsoleted by svc_getreqset().
bool_t svc_register(SVCXPRT *xprt, u_long prognum, u_long versnum, void (*dispatch)(struct svc_req *, SVCXPRT *), int protocol)
Associates prognum and versnum with the service dispatch procedure, dispatch(). If protocol is zero, the service is not registered
with the rpcbind(8) service. If protocol is non-zero, then a mapping of the triple (prognum, versnum, protocol) to xprt->xp_port is
established with the local rpcbind(8) service (generally protocol is zero, IPPROTO_UDP or IPPROTO_TCP). The procedure dispatch() has
the following form:
bool_t dispatch(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(2) system call to return.
bool_t svc_sendreply(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 xprt argument is the request's asso-
ciated 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(u_long prognum, u_long versnum)
Remove all mapping of the double (prognum, versnum) to dispatch routines, and of the triple (prognum, versnum, *) to port number.
void
svcerr_auth(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(SVCXPRT *xprt)
Called by a service dispatch routine that cannot successfully decode its arguments. See also svc_getargs().
void
svcerr_noproc(SVCXPRT *xprt)
Called by a service dispatch routine that does not implement the procedure number that the caller requests.
void
svcerr_noprog(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(SVCXPRT *xprt, u_long low_vers, u_long high_vers)
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(SVCXPRT *xprt)
Called by a service dispatch routine when it detects a system error not covered by any particular protocol. For example, if a ser-
vice can no longer allocate storage, it may call this routine.
void
svcerr_weakauth(SVCXPRT *xprt)
Called by a service dispatch routine that refuses to perform a remote procedure call due to insufficient authentication arguments.
The routine calls svcerr_auth(xprt, AUTH_TOOWEAK).
SVCXPRT *
svcraw_create(void)
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(int sock, u_int send_buf_size, u_int 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_fd 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 *
svcunix_create(int sock, u_int send_buf_size, u_int recv_buf_size, char *path)
This routine creates a UNIX-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. The *path argument is a variable-length file system pathname
of at most 104 characters. This file is not removed when the socket is closed. The unlink(2) system call must be used to remove the
file. Upon completion, xprt->xp_fd is the transport's socket descriptor. This routine returns NULL if it fails. Since UNIX-based
RPC uses buffered I/O, users may specify the size of buffers; values of zero choose suitable defaults.
SVCXPRT *
svcunixfd_create(int fd, u_int sendsize, u_int recvsize)
Create a service on top of any open descriptor. The sendsize and recvsize arguments indicate sizes for the send and receive buffers.
If they are zero, a reasonable default is chosen.
SVCXPRT *
svcfd_create(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.
The sendsize and recvsize arguments indicate sizes for the send and receive buffers. If they are zero, a reasonable default is cho-
sen.
SVCXPRT *
svcudp_bufcreate(int sock, u_int sendsize, u_int recvsize)
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_fd 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.
bool_t xdr_accepted_reply(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.
bool_t xdr_authunix_parms(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
bool_t xdr_callhdr(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.
bool_t xdr_callmsg(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.
bool_t xdr_opaque_auth(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 mes-
sages without using the RPC package.
struct pmap;
bool_t xdr_pmap(XDR *xdrs, struct pmap *regs)
Used for describing arguments to various rpcbind(8) procedures, externally. This routine is useful for users who wish to generate
these arguments without using the pmap_*() interface.
bool_t xdr_pmaplist(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 arguments with-
out using the pmap_*() interface.
bool_t xdr_rejected_reply(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.
bool_t xdr_replymsg(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(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(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)
Remote Procedure Calls: Protocol Specification.
Remote Procedure Call Programming Guide.
rpcgen Programming Guide.
RPC: Remote Procedure Call Protocol Specification, Sun Microsystems, Inc., USC-ISI, RFC1050.
BSD
February 16, 1988 BSD