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CALLRPC(3) Library Functions Manual CALLRPC(3)

callrpc, clnt_broadcast, clnt_call, clnt_control, clnt_create, clnt_destroy, clnt_freeres, clnt_pcreateerror, clnt_perrno, clnt_perror, clnt_spcreateerror, clnt_sperrno, clnt_sperror, clntraw_create, clnttcp_create, clntudp_bufcreate, clntudp_create, clnt_geterr, get_myaddress, pmap_getmaps, pmap_getport, pmap_rmtcall, pmap_set, pmap_unset, registerrpc, rpc_createerr, svc_destroy, svc_fds, svc_fdset, svc_freeargs, svc_getargs, svc_getcaller, svc_getreq, svc_getreq_common, svc_getreq_poll, svc_getreqset, svc_getreqset2, svc_register, svc_max_pollfd, svc_pollfd, svc_run, svc_sendreply, svc_unregister, svcerr_auth, svcerr_decode, svcerr_noproc, svcerr_noprog, svcerr_progvers, svcerr_systemerr, svcerr_weakauth, svcfd_create, svcraw_create, svctcp_create, svcudp_create, svcudp_bufcreate, 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

#include <rpc/rpc.h>

int
callrpc(char *host, u_long prognum, u_long versnum, u_long procnum, xdrproc_t inproc, char *in, xdrproc_t outproc, char *out);

enum clnt_stat
clnt_broadcast(u_long prognum, u_long versnum, u_long procnum, xdrproc_t inproc, char *in, xdrproc_t outproc, char *out, resultproc_t eachresult);

enum clnt_stat
clnt_call(CLIENT *clnt, u_long procnum, xdrproc_t inproc, char *in, xdrproc_t outproc, char *out, struct timeval tout);

int
clnt_destroy(CLIENT *clnt);

CLIENT *
clnt_create(char *host, u_long prog, u_long vers, char *proto);

bool_t
clnt_control(CLIENT *cl, int req, char *info);

int
clnt_freeres(CLIENT *clnt, xdrproc_t outproc, char *out);

void
clnt_geterr(CLIENT *clnt, struct rpc_err *errp);

void
clnt_pcreateerror(char *s);

void
clnt_perrno(enum clnt_stat stat);

int
clnt_perror(CLIENT *clnt, char *s);

char *
clnt_spcreateerror(char *s);

char *
clnt_sperrno(enum clnt_stat stat);

char *
clnt_sperror(CLIENT *rpch, char *s);

CLIENT *
clntraw_create(u_long prognum, u_long versnum);

CLIENT *
clnttcp_create(struct sockaddr_in *addr, u_long prognum, u_long versnum, int *sockp, u_int sendsz, u_int recvsz);

CLIENT *
clntudp_create(struct sockaddr_in *addr, u_long prognum, u_long versnum, struct timeval wait, int *sockp);

CLIENT *
clntudp_bufcreate(struct sockaddr_in *addr, u_long prognum, u_long versnum, struct timeval wait, int *sockp, unsigned int sendsize, unsigned int recosize);

int
get_myaddress(struct sockaddr_in *addr);

struct pmaplist *
pmap_getmaps(struct sockaddr_in *addr);

u_short
pmap_getport(struct sockaddr_in *addr, u_long prognum, u_long versnum, u_long protocol);

enum clnt_stat
pmap_rmtcall(struct sockaddr_in *, u_long prog, u_long vers, u_long proc, xdrproc_t inp, char *in, xdrproc_t outp, char *out, struct timeval tv, u_long *portp);

int
pmap_set(u_long prognum, u_long versnum, u_int protocol, int port);

int
pmap_unset(u_long prognum, u_long versnum);

int
registerrpc(u_long prognum, u_long versnum, u_long procnum, char *(*procname)() , xdrproc_t inproc, xdrproc_t outproc);

struct rpc_createerr rpc_createerr;

int
svc_destroy(SVCXPRT *xprt);

struct pollfd *svc_pollfd;
int svc_max_pollfd;
fd_set svc_fdset;
fd_set *__svc_fdset;
int __svc_fdsetsize;
int svc_fds;

int
svc_freeargs(SVCXPRT *xprt, xdrproc_t inproc, char *in);

int
svc_getargs(SVCXPRT *xprt, xdrproc_t inproc, char *in);

struct sockaddr_in *
svc_getcaller(SVCXPRT *xprt);

int
svc_getreq_common(int fd);

int
svc_getreq_poll(struct pollfd *pfds, const int pollretval);

int
svc_getreqset(fd_set *rdfds);

int
svc_getreqset2(fd_set *rdfds, int width);

int
svc_getreq(int rdfds);

int
svc_register(SVCXPRT *xprt, u_long prognum, u_long versnum, void (*dispatch)(), u_long protocol);

int
svc_run(void);

int
svc_sendreply(SVCXPRT *xprt, xdrproc_t outproc, char *out);

void
svc_unregister(u_long prognum, u_long versnum);

void
svcerr_auth(SVCXPRT *xprt, enum auth_stat why);

void
svcerr_decode(SVCXPRT *xprt);

void
svcerr_noproc(SVCXPRT *xprt);

void
svcerr_noprog(SVCXPRT *xprt);

void
svcerr_progvers(SVCXPRT *xprt);

void
svcerr_systemerr(SVCXPRT *xprt);

void
svcerr_weakauth(SVCXPRT *xprt);

SVCXPRT *
svcraw_create(void);

SVCXPRT *
svctcp_create(int sock, u_int send_buf_size, u_int recv_buf_size);

SVCXPRT *
svcfd_create(int fd, u_int sendsize, u_int recvsize);

SVCXPRT *
svcudp_create(int sock);

SVCXPRT *
svcudp_bufcreate(int sock, u_int sendsz, u_int recvsz);

bool_t
xdr_accepted_reply(XDR *xdrs, struct accepted_reply *ar);

bool_t
xdr_authunix_parms(XDR *xdrs, struct authunix_parms *aupp);

void
xdr_callhdr(XDR *xdrs, struct rpc_msg *chdr);

int
xdr_callmsg(XDR *xdrs, struct rpc_msg *cmsg);

int
xdr_opaque_auth(XDR *xdrs, struct opaque_auth *ap);

int
xdr_pmap(XDR *xdrs, struct pmap *regs);

int
xdr_pmaplist(XDR *xdrs, struct pmaplist **rp);

int
xdr_rejected_reply(XDR *xdrs, struct rejected_reply *rr);

int
xdr_replymsg(XDR *xdrs, struct rpc_msg *rmsg);

void
xprt_register(SVCXPRT *xprt);

void
xprt_unregister(SVCXPRT *xprt);

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.

() calls 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 () for restrictions. You do not have control of timeouts or authentication using this routine.

() is 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:

int
(char *out, struct sockaddr_in *addr)

where out is the same as out passed to (), 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.

() is 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.

() is 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.

() is a 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 clnt_control(). This routine returns NULL if it fails.

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.

() is 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 timeout
CLGET_TIMEOUT	struct timeval	get total timeout

Note: if you set the timeout using (), 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.

() is 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.

() is a macro that copies the error structure out of the client handle to the structure at address errp.

() 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. Used when a clnt_create(), clntraw_create(), clnttcp_create(), or clntudp_create() call fails.

() prints a message to standard error corresponding to the condition indicated by stat. Used after callrpc().

() prints 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().

() is 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.

() takes the same arguments as clnt_perrno(), but instead of sending a message to the standard error indicating why an RPC call failed, returns a pointer to a string which contains the message. Unlike clnt_perror(), it does not append a newline character to the end of the message.

() 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 (), or if a message format different than that supported by clnt_perrno() is to be used.

Note: unlike () and (), clnt_sperrno() returns a pointer to static data, but the result will not get overwritten on each call.

() is 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.

() is a routine which 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.

() is a routine which 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(8) 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.

() is a routine which 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(8) 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 routine returns NULL if it fails.

() is like clntudp_create(), except that it allows the user to specify the maximum packet size for sending and receiving UDP-based RPC messages instead of using the default size limit of 8800 bytes.

() stuffs 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.

() is a function interface to the portmap(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.

() is a user interface to the portmap(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 portmap(8) service. In the latter case, the global variable rpc_createerr contains the RPC status.

() is a user interface to the portmap(8) service, which instructs portmap(8) 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().

() is a user interface to the portmap(8) service, which establishes a mapping between the triple [prognum, versnum, protocol] and port on the machine's portmap(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().

() is a user interface to the portmap(8) service, which destroys all mapping between the triple [prognum, versnum, *] and ports on the machine's portmap(8) service. This routine returns one if it succeeds, zero otherwise.

() will register a 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); procname 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 () for restrictions.

rpc_createerr is a global variable whose value is set by any RPC client creation routine that does not succeed. Use the routine () to print the reason why.

() is 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.

svc_pollfd is a global variable reflecting the RPC service side's read file descriptor array. This variable is only of interest if service implementors do not call (), but rather do their own asynchronous event processing. This variable is read-only, and it may change after calls to svc_getreq_poll() or any creation routines. Do not pass it directly to poll(2)! Instead, make a copy and pass that instead.

svc_max_pollfd is a global variable containing the maximum length of the svc_pollfd array. svc_max_pollfd is not a hard limit; it will grow automatically as needed. This variable is read-only, and it may change after calls to () or any creation routines. The purpose of svc_max_pollfd is to allow a service implementor to make a copy of svc_pollfd that may in turn be passed to poll(2).

__svc_fdset and __svc_fdsetsize are global variables reflecting the RPC service side's read file descriptor bit mask. __svc_fdsetsize is a count of the number of checkable bits in __svc_fdset, and can expand to the full size that select(2) supports, hence exceeding FD_SETSIZE if required. These variables are only of interest if service implementors do not call (), but rather do their own asynchronous event processing. This variable is read-only, and it may change after calls to svc_getreqset() or any creation routines. Do not pass its address to select(2)! Instead, pass the address of a copy. These variables are considered obsolete; new programs should use svc_pollfd and svc_max_pollfd instead.

svc_fdset is similar to __svc_fdset but limited to FD_SETSIZE descriptors. This is only of interest if service implementors do not call (), but rather do their own asynchronous event processing. This variable is read-only, and it may change after calls to svc_getreqset() or any creation routines. Do not pass it directly to select(2)! Instead, make a copy and pass that instead.

Additionally, 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. This variable is considered obsolete; new programs should use svc_pollfd which does not have this limit.

svc_fds is similar to svc_fdset, but limited to 32 descriptors. This interface is obsoleted by svc_fdset and is included for source compatibility only.

() is 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.

() is 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.

() is the approved way of getting the network address of the caller of a procedure associated with the RPC service transport handle, xprt.

() is called to handle a request on the given socket. It is used internally by svc_getreq_poll(), svc_getreqset(), svc_getreqset2(), and svc_getreq().

() is a routine which 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 poll(2) system call has determined that an RPC request has arrived on some RPC socket(s); pollretval is the value returned by poll(2) and pfds is the array of pollfd structures passed to poll(2). The routine returns when all sockets described by pollfd have been serviced.

() is a routine which 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.

() is a non-standard routine which 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. This interface is non-portable, but provided for applications which need to deal with large fd_set sizes.

() is similar to svc_getreqset, but limited to 32 descriptors. This interface is obsoleted by svc_getreq_poll and svc_getreqset.

() associates prognum and versnum with the service dispatch procedure, dispatch. If protocol is zero, the service is not registered with the portmap(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 portmap(8) service (generally protocol is zero, IPPROTO_UDP or IPPROTO_TCP). The procedure dispatch has the following form: int (struct svc_req *request, SVCXPRT *xprt) The svc_register() routine returns one if it succeeds, and zero otherwise.

() never returns. It waits for RPC requests to arrive, and calls the appropriate service procedure using svc_getreq_poll() when one arrives. This procedure is usually waiting for a poll(2) system call to return.

() is 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.

() removes all mapping of the double [prognum, versnum] to dispatch routines, and of the triple [prognum, versnum, *] to port number.

() is called by a service dispatch routine that refuses to perform a remote procedure call due to an authentication error.

() is called by a service dispatch routine that cannot successfully decode its parameters. See also svc_getargs().

() is called by a service dispatch routine that does not implement the procedure number that the caller requests.

() is called when the desired program is not registered with the RPC package. Service implementors usually do not need this routine.

() is called when the desired version of a program is not registered with the RPC package. Service implementors usually do not need this routine.

() is 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.

() is 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).

() is a routine which 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.

() is a routine which 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.

() will 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.

() is a routine which 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.

() is like svcudp_create(), except that it allows the user to specify the maximum packet size for sending and receiving UDP-based RPC messages instead of using the default size limit of 8800 bytes.

() is used for encoding RPC reply messages. This routine is useful for users who wish to generate RPC-style messages without using the RPC package.

() is used for describing UNIX credentials. This routine is useful for users who wish to generate these credentials without using the RPC authentication package.

() is 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.

() is used for describing RPC call messages. This routine is useful for users who wish to generate RPC-style messages without using the RPC package.

() is 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.

() is used for describing parameters to various portmap(8) procedures, externally. This routine is useful for users who wish to generate these parameters without using the pmap interface.

() is 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.

() is used for describing RPC reply messages. This routine is useful for users who wish to generate RPC-style messages without using the RPC package.

() is used for describing RPC reply messages. This routine is useful for users who wish to generate RPC-style messages without using the RPC package.

() is used to register transport handles. After RPC service transport handles are created, they should register themselves with the RPC service package. This routine modifies the global variables svc_pollfd, svc_fdset, __svc_fdset and may modify svc_max_pollfd and __svc_fdsetsize. Service implementors usually do not need this routine.

() is used to unregister a transport handle. Before an RPC service transport handle is destroyed, it should unregister itself with the RPC service package. This routine modifies the global variable svc_pollfd, svc_fdset, and __svc_fdset. Service implementors usually do not need this routine.

rpcgen(1), poll(2), select(2), authnone_create(3), getrpcent(3), getrpcport(3), xdr(3), rpc(5), portmap(8)

Remote Procedure Calls: Protocol Specification, Sun Microsystems, Inc..

Remote Procedure Call Programming Guide, Sun Microsystems, Inc..

rpcgen Programming Guide, Sun Microsystems, Inc..

RPC: Remote Procedure Call Protocol Specification Version 2, RFC 1057, Sun Microsystems, Inc., June 1988.

January 1, 2022 OpenBSD-7.6