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RPC !!!RPC NAME SYNOPSIS AND DESCRIPTION SEE ALSO ---- !!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__(3N). Secure RPC can be used only if DES encryption is available. __#include __ 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 ``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(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 timeout CLGET_TIMEOUT struct timeval get total timeout Note: if you set the timeout using __clnt_control()__, the timeout parameter passed to __clnt_call()__ will be ignored in all future calls. CLGET_SERVER_ADDR struct sockaddr_in get server's address The following operations are valid for UDP only: CLSET_RETRY_TIMEOUT struct timeval set the retry timeout CLGET_RETRY_TIMEOUT struct timeval get the retry timeout The retry timeout is the time that UDP RPC waits for the server to reply before retransmitting the request. __clnt_freeres(clnt, outproc, out) CLIENT *clnt; xdrproc_t outproc; char *out; __ A macro that frees any data allocated by the RPC/XDR system when it decoded the results of an RPC call. The parameter ''out'' is the address of the results, and ''outproc'' is the XDR routine describing the results. This routine returns one if the results were successfully freed, and zero otherwise. __void clnt_geterr(clnt, errp) CLIENT *clnt; struct rpc_err *errp; __ A macro that copies the error structure out of the client 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-__ 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-__ 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-__ 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 maximun 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 failured to contact the remote __portmap__ service. In the latter case, the global variable __rpc_createerr()__ contains the RPC status. __enum clnt_stat pmap_rmtcall(addr, prognum, versnum, procnum, inproc, in, outproc, out, tout, portp) struct sockaddr_in *addr; u_long prognum, versnum, procnum; char *in, *out; xdrproc_t inproc, outproc; struct timeval tout; u_long *portp; __ A user interface to the __portmap__ service, which instructs __portmap__ on the host at IP address ''*addr'' to make an RPC call on your behalf to a procedure on that host. The parameter ''*portp'' will be modified to the program's port number if the procedure succeeds. The definitions of other parameters are discussed in __callrpc()__ and __clnt_call()__. This procedure should be used for a ``ping'' and nothing else. See also __clnt_broadcast()__. __pmap_set(prognum, versnum, protocol, port) u_long prognum, versnum, protocol; u_short port; __ A user interface to the __portmap__ service, which establishes a mapping between the triple [[''prognum'',''versnum'',''protocol''] and ''port'' on the machine's __portmap__ service. The value of ''protocol'' is most likely __IPPROTO_UDP__ or __IPPROTO_TCP__ . This routine returns one if it succeeds, zero otherwise. Automatically done by __svc_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-__ 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 * 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-__ is the transport's socket descriptor, and __xprt-__ 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 * 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 * 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-__ is the transport's socket descriptor, and __xprt-__ is the transport's port number. This routine returns NULL if it fails. This allows the user to specify the maximun packet size for sending and receiving UDP -based RPC messages. __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__(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 . ----
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