rpcgen - an RPC protocol compiler
rpcgen infile
rpcgen [-Dname[=value]] [-T] [-K secs] infile
rpcgen -c|-h|-l|-m|-t [-o outfile ] infile
rpcgen [-I] -s nettype [-o outfile] infile
rpcgen -n netid [-o outfile] infile
rpcgen is a tool that generates C code to implement an RPC protocol.
The input to rpcgen is a language similar to C known as RPC Language
(Remote Procedure Call Language).
rpcgen is normally used as in the first synopsis where it takes an
input file and generates up to four output files. If the infile is
named proto.x, then rpcgen will generate a header file in proto.h, XDR
routines in proto_xdr.c, server-side stubs in proto_svc.c, and clientside
stubs in proto_clnt.c. With the -T option, it will also generate
the RPC dispatch table in proto_tbl.i. With the -Sc option, it will
also generate sample code which would illustrate how to use the remote
procedures on the client side. This code would be created in
proto_client.c. With the -Ss option, it will also generate a sample
server code which would illustrate how to write the remote procedures.
This code would be created in proto_server.c.
The server created can be started both by the port monitors (for example,
inetd or listen) or by itself. When it is started by a port monitor,
it creates servers only for the transport for which the file
descriptor 0 was passed. The name of the transport must be specified
by setting up the environmental variable PM_TRANSPORT. When the server
generated by rpcgen is executed, it creates server handles for all the
transports specified in NETPATH environment variable, or if it is
unset, it creates server handles for all the visible transports from
/etc/netconfig file. Note: the transports are chosen at run time and
not at compile time. When the server is self-started, it backgrounds
itself by default. A special define symbol RPC_SVC_FG can be used to
run the server process in foreground.
The second synopsis provides special features which allow for the creation
of more sophisticated RPC servers. These features include support
for user provided #defines and RPC dispatch tables. The entries
in the RPC dispatch table contain:
? pointers to the service routine corresponding to that procedure,
? a pointer to the input and output arguments
? the size of these routines
A server can use the dispatch table to check authorization and then to
execute the service routine; a client library may use it to deal with
the details of storage management and XDR data conversion.
The other three synopses shown above are used when one does not want to
generate all the output files, but only a particular one. Some examples
of their usage is described in the EXAMPLE section below. When
rpcgen is executed with the -s option, it creates servers for that particular
class of transports. When executed with the -n option, it creates
a server for the transport specified by netid. If infile is not
specified, rpcgen accepts the standard input.
The C preprocessor, cc -E [see cc(1)
], is run on the input file before
it is actually interpreted by rpcgen. For each type of output file,
rpcgen defines a special preprocessor symbol for use by the rpcgen programmer:
RPC_HDR RPC_XDR RPC_SVC RPC_CLNT RPC_TBL
Any line beginning with ‘%’ is passed directly into the output file,
uninterpreted by rpcgen.
For every data type referred to in infile, rpcgen assumes that there
exists a routine with the string xdr_ prepended to the name of the data
type. If this routine does not exist in the RPC/XDR library, it must
be provided. Providing an undefined data type allows customization of
XDR routines.
The following options are available:
-a -b -5 -c -C -k -Dname[=value]#define directive in
the source. If no value is given, value is defined as 1. This
option may be specified more than once.
-h C data-definitions (a header file). -T option can
be used in conjunction to produce a header file which supports
RPC dispatch tables.
-I -s. Using -I allows starting a service by either method.
-K secsrpcgen wait 120 seconds after
servicing a request before exiting. That interval can be
changed using the -K flag. To create a server that exits immediately
upon servicing a request, -K 0 can be used. To create a
server that never exits, the appropriate argument is -K -1.
When monitoring for a server, some portmonitors, like lis_ten(1M)
,
always spawn a new process in response to a service
request. If it is known that a server will be used with such a
monitor, the server should exit immediately on completion. For
such servers, rpcgen should be used with -K -1.
-l -m -n netid-N -o outfile-c, -h, -l, -m, -n, -s, -s -sand -t
modes only).
-s nettypenetpath, visi_ble,
circuit_n, circuit_v, datagram_n, datagram_v, tcp, and udp
[see rpc(3N)
for the meanings associated with these classes].
This option may be specified more than once. Note: the transports
are chosen at run time and not at compile time.
-Sc -Ss -t -T
The options -c, -h, -l, -m, -s and -t are used exclusively to generate
a particular type of file, while the options -D and -T are global and
can be used with the other options.
The RPC Language does not support nesting of structures. As a workaround, structures can be declared at the top-level, and their name used inside other structures in order to achieve the same effect.
Name clashes can occur when using program definitions, since the apparent scoping does not really apply. Most of these can be avoided by giving unique names for programs, versions, procedures and types.
The server code generated with -n option refers to the transport indicated
by netid and hence is very site specific.
The following example:
$ rpcgen -T prot.x
generates the five files: prot.h, prot_clnt.c, prot_svc.c, prot_xdr.c
and prot_tbl.i.
The following example sends the C data-definitions (header file) to the standard output.
$ rpcgen -h prot.x
To send the test version of the -DTEST, server side stubs for all the
transport belonging to the class datagram_n to standard output, use:
$ rpcgen -s datagram_n -DTEST prot.x
To create the server side stubs for the transport indicated by netid
tcp, use:
$ rpcgen -n tcp -o prot_svc.c prot.x
gcc(1) .