rpc.3n

早期freebsd实现

.\" @(#)rpc.3n	2.4 88/08/08 4.0 RPCSRC; from 1.19 88/06/24 SMI
.TH RPC 3N "16 February 1988"
.SH NAME
rpc \- library routines for remote procedure calls
.SH 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.
.LP
Routines that are used for Secure RPC (DES authentication) are described in
.BR rpc_secure (3N).
Secure RPC can be used only if DES encryption is available.
.LP
.ft B
.nf
.sp .5
#include <rpc/rpc.h>
.fi
.ft R
.br
.if t .ne 8
.LP
.ft B
.nf
.sp .5
void
auth_destroy(auth)
\s-1AUTH\s0 *auth;
.fi
.ft R
.IP
A macro that destroys the authentication information associated with
.IR auth .
Destruction usually involves deallocation of private data
structures. The use of
.I auth
is undefined after calling
.BR auth_destroy(\|) .
.br
.if t .ne 6
.LP
.ft B
.nf
.sp .5
\s-1AUTH\s0 *
authnone_create(\|)
.fi
.ft R
.IP
Create and returns an
.SM RPC
authentication handle that passes nonusable authentication
information with each remote procedure call. This is the
default authentication used by
.SM RPC.
.if t .ne 10
.LP
.ft B
.nf
.sp .5
\s-1AUTH\s0 *
authunix_create(host, uid, gid, len, aup_gids)
char *host;
int uid, gid, len, *aup.gids;
.fi
.ft R
.IP
Create and return an
.SM RPC
authentication handle that contains
.UX
authentication information.
The parameter
.I host
is the name of the machine on which the information was
created;
.I uid
is the user's user
.SM ID ;
.I gid
is the user's current group
.SM ID ;
.I len
and
.I aup_gids
refer to a counted array of groups to which the user belongs.
It is easy to impersonate a user.
.br
.if t .ne 5
.LP
.ft B
.nf
.sp .5
\s-1AUTH\s0 *
authunix_create_default(\|)
.fi
.ft R
.IP
Calls
.B authunix_create(\|)
with the appropriate parameters.
.br
.if t .ne 13
.LP
.ft B
.nf
.sp .5
callrpc(host, prognum, versnum, procnum, inproc, in, outproc, out)
char *host;
u_long prognum, versnum, procnum;
char *in, *out;
xdrproc_t inproc, outproc;
.fi
.ft R
.IP
Call the remote procedure associated with
.IR prognum ,
.IR versnum ,
and
.I procnum
on the machine,
.IR host .
The parameter
.I in
is the address of the procedure's argument(s), and
.I out
is the address of where to place the result(s);
.I inproc
is used to encode the procedure's parameters, and
.I outproc
is used to decode the procedure's results.
This routine returns zero if it succeeds, or the value of
.B "enum clnt_stat"
cast to an integer if it fails.
The routine
.B clnt_perrno(\|)
is handy for translating failure statuses into messages.
.IP
Warning: calling remote procedures with this routine
uses
.SM UDP/IP
as a transport; see
.B clntudp_create(\|)
for restrictions.
You do not have control of timeouts or authentication using
this routine.
.br
.if t .ne 16
.LP
.ft B
.nf
.sp .5
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;
.fi
.ft R
.IP
Like
.BR callrpc(\|) ,
except the call message is broadcast to all locally
connected broadcast nets. Each time it receives a
response, this routine calls
.BR eachresult(\|) ,
whose form is:
.IP
.RS 1i
.ft B
.nf
eachresult(out, addr)
char *out;
struct sockaddr_in *addr;
.ft R
.fi
.RE
.IP
where
.I out
is the same as
.I out
passed to
.BR clnt_broadcast(\|) ,
except that the remote procedure's output is decoded there;
.I addr
points to the address of the machine that sent the results.
If
.B eachresult(\|)
returns zero,
.B clnt_broadcast(\|)
waits for more replies; otherwise it returns with appropriate
status.
.IP
Warning: broadcast sockets are limited in size to the
maximum transfer unit of the data link. For ethernet,
this value is 1500 bytes.
.br
.if t .ne 13
.LP
.ft B
.nf
.sp .5
enum clnt_stat
clnt_call(clnt, procnum, inproc, in, outproc, out, tout)
\s-1CLIENT\s0 *clnt;
u_long
procnum;
xdrproc_t inproc, outproc;
char *in, *out;
struct timeval tout;
.fi
.ft R
.IP
A macro that calls the remote procedure
.I procnum
associated with the client handle,
.IR clnt ,
which is obtained with an
.SM RPC
client creation routine such as
.BR clnt_create(\|) .
The parameter
.I in
is the address of the procedure's argument(s), and
.I out
is the address of where to place the result(s);
.I inproc
is used to encode the procedure's parameters, and
.I outproc
is used to decode the procedure's results;
.I tout
is the time allowed for results to come back.
.br
.if t .ne 7
.LP
.ft B
.nf
.sp .5
clnt_destroy(clnt)
\s-1CLIENT\s0 *clnt;
.fi
.ft R
.IP
A macro that destroys the client's
.SM RPC
handle. Destruction usually involves deallocation
of private data structures, including
.I clnt
itself.  Use of
.I clnt
is undefined after calling
.BR clnt_destroy(\|) .
If the
.SM RPC
library opened the associated socket, it will close it also.
Otherwise, the socket remains open.
.br
.if t .ne 10
.LP
.ft B
.nf
.sp .5
\s-1CLIENT\s0 *
clnt_create(host, prog, vers, proto)
char *host;
u_long prog, vers;
char *proto;
.fi
.ft R
.IP
Generic client creation routine.
.I host
identifies the name of the remote host where the server
is located.
.I proto
indicates which kind of transport protocol to use. The
currently supported values for this field are \(lqudp\(rq
and \(lqtcp\(rq.
Default timeouts are set, but can be modified using
.BR clnt_control(\|) .
.IP
Warning: Using
.SM UDP
has its shortcomings.  Since
.SM UDP\s0-based
.SM 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.
.br
.if t .ne 10
.LP
.ft B
.nf
.sp .5
bool_t
clnt_control(cl, req, info)
\s-1CLIENT\s0 *cl;
char *info;
.fi
.ft R
.IP
A macro used to change or retrieve various information
about a client object.
.I req
indicates the type of operation, and
.I info
is a pointer to the information. For both
.SM UDP
and
.SM TCP\s0,
the supported values of
.I req
and their argument types and what they do are:
.IP
.nf
.ta +2.0i +2.0i +2.0i
.SM CLSET_TIMEOUT\s0	struct timeval	set total timeout
.SM CLGET_TIMEOUT\s0	struct timeval	get total timeout
.fi
.IP
Note: if you set the timeout using
.BR clnt_control(\|) ,
the timeout parameter passed to
.B clnt_call(\|)
will be ignored in all future calls.
.IP
.nf
.SM CLGET_SERVER_ADDR\s0	struct sockaddr_in 	get server's address
.fi
.br
.IP
The following operations are valid for
.SM UDP
only:
.IP
.nf
.ta +2.0i ; +2.0i ; +2.0i
.SM CLSET_RETRY_TIMEOUT\s0		struct timeval	set the retry timeout
.SM CLGET_RETRY_TIMEOUT\s0		struct timeval	get the retry timeout
.fi
.br
.IP
The retry timeout is the time that
.SM "UDP RPC"
waits for the server to reply before
retransmitting the request.
.br
.if t .ne 10
.LP
.ft B
.nf
.sp .5
clnt_freeres(clnt, outproc, out)
\s-1CLIENT\s0 *clnt;
xdrproc_t outproc;
char *out;
.fi
.ft R
.IP
A macro that frees any data allocated by the
.SM RPC/XDR
system when it decoded the results of an
.SM RPC
call.  The
parameter
.I out
is the address of the results, and
.I outproc
is the
.SM XDR
routine describing the results.
This routine returns one if the results were successfully
freed,
and zero otherwise.
.br
.if t .ne 6
.LP
.ft B
.nf
.sp .5
void
clnt_geterr(clnt, errp)
\s-1CLIENT\s0 *clnt;
struct rpc_err *errp;
.fi
.ft R
.IP
A macro that copies the error structure out of the client
handle
to the structure at address
.IR errp .
.br
.if t .ne 8
.LP
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.nf
.sp .5
void
clnt_pcreateerror(s)
char *s;
.fi
.ft R
.IP
Print a message to standard error indicating
why a client
.SM RPC
handle could not be created.
The message is prepended with string
.I s
and a colon.
Used when a
.BR clnt_create(\|) ,
.BR clntraw_create(\|) ,
.BR clnttcp_create(\|) ,
or
.B clntudp_create(\|)
call fails.
.br
.if t .ne 8
.LP
.ft B
.nf
.sp .5
void
clnt_perrno(stat)
enum clnt_stat stat;
.fi
.ft R
.IP
Print a message to standard error corresponding
to the condition indicated by
.IR stat .
Used after
.BR callrpc(\|) .
.br
.if t .ne 8
.LP
.ft B
.nf
.sp .5
clnt_perror(clnt, s)
\s-1CLIENT\s0 *clnt;
char *s;
.fi
.ft R
.IP
Print a message to standard error indicating why an
.SM RPC
call failed;
.I clnt
is the handle used to do the call.
The message is prepended with string
.I s
and a colon.
Used after
.BR clnt_call(\|) .
.br
.if t .ne 9
.LP
.ft B
.nf
.sp .5
char *
clnt_spcreateerror
char *s;
.fi
.ft R
.IP
Like
.BR clnt_pcreateerror(\|) ,
except that it returns a string
instead of printing to the standard error.
.IP
Bugs: returns pointer to static data that is overwritten
on each call.
.br
.if t .ne 9
.LP
.ft B
.nf
.sp .5
char *
clnt_sperrno(stat)
enum clnt_stat stat;
.fi
.ft R
.IP
Take the same arguments as
.BR clnt_perrno(\|) ,
but instead of sending a message to the standard error
indicating why an
.SM RPC
call failed, return a pointer to a string which contains
the message.  The string ends with a
.SM NEWLINE\s0.
.IP
.B clnt_sperrno(\|)
is used instead of
.B 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
.BR printf ,
or if a message format different than that supported by
.B clnt_perrno(\|)
is to be used.
Note: unlike
.B clnt_sperror(\|)
and
.BR clnt_spcreaterror(\|) ,
.B clnt_sperrno(\|)
returns pointer to static data, but the
result will not get overwritten on each call.
.br
.if t .ne 7
.LP
.ft B
.nf
.sp .5
char *
clnt_sperror(rpch, s)
\s-1CLIENT\s0 *rpch;
char *s;
.fi
.ft R
.IP
Like
.BR clnt_perror(\|) ,
except that (like
.BR clnt_sperrno(\|) )
it returns a string instead of printing to standard error.
.IP
Bugs: returns pointer to static data that is overwritten
on each call.
.br
.if t .ne 10
.LP
.ft B
.nf
.sp .5
\s-1CLIENT\s0 *
clntraw_create(prognum, versnum)
u_long prognum, versnum;
.fi
.ft R
.IP
This routine creates a toy
.SM RPC
client for the remote program
.IR prognum ,
version
.IR versnum .
The transport used to pass messages to the service is
actually a buffer within the process's address space, so the
corresponding
.SM RPC
server should live in the same address space; see
.BR svcraw_create(\|) .
This allows simulation of
.SM RPC
and acquisition of
.SM RPC
overheads, such as round trip times, without any
kernel interference. This routine returns
.SM NULL
if it fails.
.br
.if t .ne 15
.LP
.ft B
.nf
.sp .5
\s-1CLIENT\s0 *
clnttcp_create(addr, prognum, versnum, sockp, sendsz, recvsz)
struct sockaddr_in *addr;
u_long prognum, versnum;
int *sockp;
u_int sendsz, recvsz;
.fi
.ft R
.IP
This routine creates an
.SM RPC
client for the remote program
.IR prognum ,
version
.IR versnum ;
the client uses
.SM TCP/IP
as a transport. The remote program is located at Internet
address
.IR *addr .
If
.\"The following in-line font conversion is necessary for the hyphen indicator
\fB\%addr\->sin_port\fR
is zero, then it is set to the actual port that the remote
program is listening on (the remote
.B portmap
service is consulted for this information). The parameter
.I sockp
is a socket; if it is
.BR \s-1RPC_ANYSOCK\s0 ,
then this routine opens a new one and sets
.IR sockp .
Since
.SM TCP\s0-based
.SM RPC
uses buffered
.SM I/O ,
the user may specify the size of the send and receive buffers
with the parameters
.I sendsz
and
.IR recvsz ;
values of zero choose suitable defaults.
This routine returns
.SM NULL
if it fails.
.br
.if t .ne 15
.LP
.ft B
.nf
.sp .5
\s-1CLIENT\s0 *
clntudp_create(addr, prognum, versnum, wait, sockp)
struct sockaddr_in *addr;
u_long prognum, versnum;
struct timeval wait;
int *sockp;
.fi
.ft R
.IP
This routine creates an
.SM RPC
client for the remote program
.IR prognum ,
version
.IR versnum ;
the client uses use
.SM UDP/IP
as a transport. The remote program is located at Internet
address
.IR addr .
If
\fB\%addr\->sin_port\fR
is zero, then it is set to actual port that the remote
program is listening on (the remote
.B portmap
service is consulted for this information). The parameter
.I sockp
is a socket; if it is
.BR \s-1RPC_ANYSOCK\s0 ,
then this routine opens a new one and sets
.IR sockp .
The
.SM UDP
transport resends the call message in intervals of
.B 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
.BR clnt_call(\|) .
.IP
Warning: since
.SM UDP\s0-based
.SM 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.
.br
.if t .ne 8
.LP
.ft B
.nf
.sp .5
\s-1CLIENT\s0 *
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;
.fi
.ft R
.IP
This routine creates an
.SM RPC
client for the remote program
.IR prognum ,
on
.IR versnum ;
the client uses use
.SM UDP/IP
as a transport. The remote program is located at Internet
address
.IR addr .
If
\fB\%addr\->sin_port\fR
is zero, then it is set to actual port that the remote
program is listening on (the remote
.B portmap
service is consulted for this information). The parameter
.I sockp
is a socket; if it is
.BR \s-1RPC_ANYSOCK\s0 ,
then this routine opens a new one and sets
.BR sockp .
The
.SM UDP
transport resends the call message in intervals of
.B 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
.BR clnt_call(\|) .
.IP
This allows the user to specify the maximun packet size for sending and receiving 
.SM UDP\s0-based
.SM RPC
messages.
.br
.if t .ne 7
.LP
.ft B
.nf
.sp .5
void
get_myaddress(addr)
struct sockaddr_in *addr;
.fi
.ft R
.IP
Stuff the machine's
.SM IP
address into
.IR *addr ,
without consulting the library routines that deal with
.BR /etc/hosts .
The port number is always set to
.BR htons(\s-1PMAPPORT\s0) .
.br
.if t .ne 10
.LP
.ft B
.nf
.sp .5
struct pmaplist *
pmap_getmaps(addr)
struct sockaddr_in *addr;
.fi
.ft R
.IP
A user interface to the
.B portmap
service, which returns a list of the current
.SM RPC
program-to-port mappings
on the host located at
.SM IP
address
.IR *addr .
This routine can return
.SM NULL .
The command
.RB ` "rpcinfo \-p" '
uses this routine.
.br
.if t .ne 12
.LP
.ft B
.nf
.sp .5
u_short
pmap_getport(addr, prognum, versnum, protocol)
struct sockaddr_in *addr;
u_long prognum, versnum, protocol;
.fi
.ft R
.IP
A user interface to the
.B portmap
service, which returns the port number
on which waits a service that supports program number
.IR prognum ,
version
.IR versnum ,
and speaks the transport protocol associated with
.IR protocol .
The value of
.I protocol
is most likely
.B
.SM IPPROTO_UDP
or 
.BR \s-1IPPROTO_TCP\s0 .
A return value of zero means that the mapping does not exist
or that
the
.SM RPC
system failured to contact the remote
.B portmap
service.  In the latter case, the global variable
.B rpc_createerr(\|)
contains the
.SM RPC
status.
.br
.if t .ne 15
.LP
.ft B
.nf
.sp .5
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;
.fi
.ft R
.IP
A user interface to the
.B portmap
service, which instructs
.B portmap
on the host at
.SM IP
address
.I *addr
to make an
.SM RPC
call on your behalf to a procedure on that host.
The parameter
.I *portp
will be modified to the program's port number if the
procedure
succeeds. The definitions of other parameters are discussed
in
.B callrpc(\|)
and
.BR clnt_call(\|) .
This procedure should be used for a \(lqping\(rq and nothing
else.
See also
.BR clnt_broadcast(\|) .
.br
.if t .ne 9
.LP
.ft B
.nf
.sp .5
pmap_set(prognum, versnum, protocol, port)