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Man page of rpc
rpc
Section: C Library Functions (3)
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NAME
rpc, rpc_functions, auth_destroy, authnone_create, authunix_create, authunix_create_default, callrpc,clnt_broadcast, clnt_call, clnt_create, clnt_control, clnt_destroy, clnt_freeres, clnt_geterr, clnt_pcreateerror, clnt_perrno, clnt_perror, clnt_spcreateerror, clnt_sperrno, clnt_sperror, clntraw_create, clnttcp_create, clntudp_create, get_myaddress, getnetname, host2netname, netname2host, netname2user, pmap_getmaps, pmap_getport, pmap_rmtcall, pmap_set, pmap_unset, registerrpc, rpc_createrr, svc_destroy, svc_fdset, svc_freeargs, 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, svcraw_create, svctcp_create, svcudp_create, usr2netname, xprt_register, xprt_unregister - Library routines for ONC remote procedure calls
SYNOPSIS
#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()
-
Creates and returns an
RPC
authentication handle that passes nonusable authentication
information with each remote procedure call. This is the
default authentication used by
ONC RPC.
AUTH *
authunix_create(host, uid, gid, len, aup_gids)
char *host;
int uid, gid, len, *aup.gids;
-
Creates and returns an
ONC RPC
authentication handle that contains
authentication information.
The
host
parameter 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.
AUTH *
authunix_create_default()
-
Calls
authunix_create()
with the appropriate parameters.
callrpc(host, prognum, versnum, procnum, inproc, in, outproc, out)
char *host;
u_int prognum, versnum, procnum;
char *in, *out;
xdrproc_t inproc, outproc;
-
Calls the remote procedure associated with
prognum, versnum, and procnum
on the machine host. The
in
parameter 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
clnt_perrno()
routine 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_int 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 the
eachresult()
routine, which has the following form:
-
-
eachresult(out, addr)
char *out;
struct sockaddr_in *addr;
-
The
out
parameter is the same as the
out
parameter 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. If
eachresult()
is
NULL
clnt_broadcast()
returns without waiting for any replies.
-
Warning: broadcast sockets are limited in size to the
maximum transfer unit of the data link. For Ethernet,
the caller's argument size should not exceed 1400 bytes.
enum clnt_stat
clnt_call(clnt, procnum, inproc, in, outproc, out, tout)
CLIENT *clnt;
u_int
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
in
parameter 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_int prog, vers;
char *proto;
-
Generic client creation routine. The
host
parameter identifies the name of the remote host where the server
is located. The
proto
parameter 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:
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;
int req;
char *info;
-
A macro that is used to change or retrieve various information
about a client object.
The req parameter
indicates the type of operation, and
info
is a pointer to the information. For
UDP
and
TCP,
req has the following supported values, argument types, and purposes:
-
CLSET_TIMEOUT | struct timeval | set total timeout
|
CLGET_TIMEOUT | struct timeval | get total timeout
|
CLGET_FD | int | get associated socket
|
CLSET_FD_CLOSE | void |
close socket on clnt_destroy()
|
CLSET_FD_NOCLOSE | void |
leave socket open on clnt_destroy()
|
-
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 |
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
out
parameter is the address of the results, and
outproc
is the
XDR
routine describing the results.
This routine returns one (1) if the results were successfully
freed,
and zero (0) 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;
-
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.
void
clnt_perrno(stat)
enum clnt_stat stat;
-
Prints a message to standard error corresponding
to the condition indicated by
stat.
Used after
callrpc().
clnt_perror(clnt, s)
CLIENT *clnt;
char *s;
-
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().
char *
clnt_spcreateerror
char *s;
-
Like
clnt_pcreateerror(),
except that it returns a string
instead of printing to the standard error.
-
Note: returns pointer to static data that is overwritten
on each call.
char *
clnt_sperrno(stat)
enum clnt_stat stat;
-
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. 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()
does not return pointer to static data so the
result will not be 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.
-
Note: returns pointer to static data that is overwritten
on each call.
CLIENT *
clntraw_create(prognum, versnum)
u_int prognum, versnum;
-
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_int prognum, versnum;
int *sockp;
u_int sendsz, recvsz;
-
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 socket 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 parameters;
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_int prognum, versnum;
struct timeval wait;
int *sockp;
-
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 socket 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.
void
get_myaddress(addr)
struct sockaddr_in *addr;
-
Places 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).
getnetname(name)
char name[MAXNETNAMELEN];
-
Installs the unique, operating-system independent network name of
the
caller in the fixed-length array
name.
Returns
TRUE
if it succeeds and
FALSE
if it fails.
host2netname(name, host, domain)
char *name;
char *host;
char *domain;
-
Converts from a domain-specific host name to an
operating-system independent network name. Return
TRUE
if it succeeds and
FALSE
if it fails. Inverse of
netname2host().
netname2host(name, host, hostlen)
char *name;
char *host;
int hostlen;
-
Converts from an operating-system independent network name to a
domain-specific host name. Returns
TRUE
if it succeeds and
FALSE
if it fails. Inverse of
host2netname().
netname2user(name, uidp, gidp, gidlenp, gidlist)
char *name;
int *uidp;
int *gidp;
int *gidlenp;
int *gidlist;
-
Converts from an operating-system independent network name to a
domain-specific user
ID.
Returns
TRUE
if it succeeds and
FALSE
if it fails. Inverse of
user2netname().
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 rpcinfo -p command uses this routine.
u_short
pmap_getport(addr, prognum, versnum, protocol)
struct sockaddr_in *addr;
u_int 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_int prognum, versnum, procnum;
char *in, *out;
xdrproc_t inproc, outproc;
struct timeval tout;
u_int *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 *portp
parameter 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_int 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
can be either
IPPROTO_UDP
or
IPPROTO_TCP.
This routine returns one (1) if it succeeds, zero (0) otherwise.
Automatically done by
svc_register().
pmap_unset(prognum, versnum)
u_int 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 (1) if it succeeds, zero (0)
otherwise.
registerrpc(prognum, versnum, procnum, procname, inproc, outproc)
u_int prognum, versnum, procnum;
char *(*procname) () ;
xdrproc_t inproc, outproc;
-
[Not Thread Safe] Registers procname procedure with the
RPC
service package. If a request arrives for prognum program,
versnum version, and procnum procedure, 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 (0) 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
clnt_pcreateerror()
routine to print the reason for the error.
svc_destroy(xprt)
SVCXPRT *
xprt;
-
[Not Thread Safe] 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 that reflects the
RPC
service side's read file descriptor bit mask; it is suitable as a
arameter 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;
-
[Not Thread Safe] 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 (0) otherwise.
svc_getargs(xprt, inproc, in)
SVCXPRT *xprt;
xdrproc_t inproc;
char *in;
-
[Not Thread Safe] A macro that decodes the arguments of an
RPC
request
associated with the
RPC
service transport handle,
xprt.
The in parameter
is the address where the arguments will be placed;
inproc
is the
XDR
routine used to decode the arguments.
This routine returns one (1) if decoding succeeds, and zero (0) otherwise.
struct sockaddr_in *
svc_getcaller(xprt)
SVCXPRT *xprt;
-
[Not Thread Safe] The approved way of getting the network address
of the caller of a procedure associated with the
RPC
service transport handle,
xprt.
svc_getreq(rdfds)
int rdfds;
-
[Not Thread Safe] Similar to
svc_getreqset(),
but limited to 32 descriptors. This interface is obsoleted by
svc_getreqset().
svc_getreqset(rdfds)
fd_set *rdfds;
-
[Not Thread Safe] 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_register(xprt, prognum, versnum, dispatch, protocol)
SVCXPRT *xprt;
u_int prognum, versnum;
void (*dispatch) ();
int protocol;
-
[Not Thread Safe] 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 dispatch procedure
has the following form:
-
dispatch(request, xprt)
struct svc_req *request;
SVCXPRT *xprt;
-
The
svc_register()
routine returns one (1) if it succeeds, and zero (0) otherwise.
svc_run()
-
[Not Thread Safe] This routine 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;
-
[Not Thread Safe] Called by an
RPC
service's dispatch routine to send the results of a
remote procedure call. The xprt parameter
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 (1) if it succeeds, zero (0) otherwise.
void
svc_unregister(prognum, versnum)
u_int prognum, versnum;
-
[Not Thread Safe] Removes 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;
-
[Not Thread Safe] 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;
-
[Not Thread Safe] Called by a service dispatch routine that cannot
successfully decode its parameters. See also
svc_getargs().
void
svcerr_noproc(xprt)
SVCXPRT *xprt;
-
[Not Thread Safe] Called by a service dispatch routine that does
not implement the procedure number that the caller requests.
void
svcerr_noprog(xprt)
SVCXPRT *xprt;
-
[Not Thread Safe] 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;
-
[Not Thread Safe] 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;
-
[Not Thread Safe] 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;
-
[Not Thread Safe] Called by a service dispatch routine that refuses
to perform a remote procedure call due to insufficient (but correct)
authentication parameters. The routine calls
svcerr_auth(xprt, AUTH_TOOWEAK).
void
svcfd_create(fd, sendsize, recvsize)
int fd;
u_int sendsize;
u_int recvsize;
-
[Not Thread Safe] Creates 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 parameters
indicate sizes for the send and receive buffers. If they are
zero (0), a reasonable default is chosen.
SVCXPRT *
svcraw_create()
-
[Not Thread Safe] 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;
-
[Not Thread Safe] Creates a
TCP/IP-based
RPC
service transport, to which it returns a pointer.
The transport is associated with the sock socket,
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 (0)
choose suitable defaults.
SVCXPRT *
svcudp_create(sock)
int sock;
-
[Not Thread Safe] Creates a
UDP/IP-based
RPC
service transport, to which it returns a pointer.
The transport is associated with the sock socket,
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.
-
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.
user2netname(name, uid, domain)
char *name;
int uid;
char *domain;
-
Converts from a domain-specific user name to an operating-system
independent network name. Returns
TRUE
if it succeeds and
FALSE
if it fails. Inverse of
netname2user().
void
xprt_register(xprt)
SVCXPRT *xprt;
-
[Not Thread Safe] 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;
-
[Not Thread Safe] 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.
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.
Unless otherwise indicated, the routines described in this
reference page are thread safe (that is, they can be used safely
in a multithreaded environment). Routines that are not thread
safe are flagged as such.
RELATED INFORMATION
xdr(3)
Remote Procedure Calls: Protocol Specification-RFC 1050
delim off
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RELATED INFORMATION
-
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Time: 02:42:11 GMT, October 02, 2010