rpcgen Man page

rpcgen General Commands Manual rpcgen


rpcgen – an RPC protocol compiler


rpcgen infile
rpcgen [-Dname[=value]] [-T] [-K secs] infile
rpcgen -c|-h|-l|-m|-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 client-
side 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 exam‐
ple, inetd or listen) or by itself. When it is started by a port moni‐
tor, 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 built for a port monitor (rpcgen -I), and that 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 cre‐
ation of more sophisticated RPC servers. These features include sup‐
port for user provided #defines and RPC dispatch tables. The entries
in the RPC dispatch table contain:
· pointers to the service routine corresponding to that proce‐
· 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 exam‐
ples of their usage is described in the EXAMPLE section below. When
rpcgen is executed with the -s option, it creates servers for that par‐
ticular class of transports. When executed with the -n option, it cre‐
ates 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], 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 pro‐

RPC_HDR defined when compiling into header files
RPC_XDR defined when compiling into XDR routines
RPC_SVC defined when compiling into server-side stubs
RPC_CLNT defined when compiling into client-side stubs
RPC_TBL defined when compiling into RPC dispatch tables

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 Generate all the files including sample code for client and
server side.

-b This generates code for the SunOS4.1 style of rpc. It is for
backward compatibility. This is the default.

-5 This generates code for the SysVr4 style of rpc. It is used by
the Transport Independent RPC that is in Svr4 systems. By
default rpcgen generates code for SunOS4.1 stype of rpc.

-c Compile into XDR routines.

-C Generate code in ANSI C. This option also generates code that
could be compiled with the C++ compiler. This is the default.

-k Generate code in K&R C. The default is ANSI C.

-Dname[=value] Define a symbol name. Equivalent to the #define directive in
the source. If no value is given, value is defined as 1. This
option may be specified more than once.

-h Compile into C data-definitions (a header file). -T option can
be used in conjunction to produce a header file which supports
RPC dispatch tables.

-I Generate a service that can be started from inetd. The default
is to generate a static service that handles transports selected
with -s. Using -I allows starting a service by either method.

-K secs
By default, services created using rpcgen wait 120 seconds after
servicing a request before exiting. That interval can be
changed using the -K flag. To create a server that exits imme‐
diately 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 Compile into client-side stubs.

-m Compile into server-side stubs, but do not generate a “main”
routine. This option is useful for doing callback-routines and
for users who need to write their own “main” routine to do ini‐

-M Generate multithread-safe stubs for passing arguments and
results between rpcgen-generated code and user written code.
This option is useful for users who want to use threads in their

-n netid
Compile into server-side stubs for the transport specified by
netid. There should be an entry for netid in the netconfig
database. This option may be specified more than once, so as to
compile a server that serves multiple transports.

-N Use the newstyle of rpcgen. This allows procedures to have mul‐
tiple arguments. It also uses the style of parameter passing
that closely resembles C. So, when passing an argument to a
remote procedure you do not have to pass a pointer to the argu‐
ment but the argument itself. This behaviour is different from
the oldstyle of rpcgen generated code. The newstyle is not the
default case because of backward compatibility.

-o outfile
Specify the name of the output file. If none is specified,
standard output is used (-c, -h, -l, -m, -n, -s, -Sc, -Sm, -Ss,
and -t modes only).

-s nettype
Compile into server-side stubs for all the transports belonging
to the class nettype. The supported classes are netpath, 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 trans‐
ports are chosen at run time and not at compile time.

-Sc Generate sample code to show the use of remote procedure and how
to bind to the server before calling the client side stubs gen‐
erated by rpcgen.

-Sm Generate a sample Makefile which can be used for compiling the

-Ss Generate skeleton code for the remote procedures on the server
side. You would need to fill in the actual code for the remote

-t Compile into RPC dispatch table.

-T Generate the code to support RPC dispatch tables.

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 work-
around, 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 appar‐
ent 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 indi‐
cated 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