rpcgen(1tcp)

rpcgen -- RPC protocol compiler

Synopsis

rpcgen infile

rpcgen [-Dname[=value]] [-T] [-K secs] infile

rpcgen -a | -b | -c | -C | -h | -I | -l | -L | -m | -N | -Sc | -Ss | -Sm | -t [-o outfile] infile

rpcgen -s nettype [-o outfile] infile

rpcgen -n netid [-o outfile] infile

rpcgen -i size

rpcgen -Y path

Description

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).

Options

rpcgen takes the following options:

-a: Generate all files, including samples.
-b: Backward compatibility mode (generates code for SunOS 4.1).
-c: Compile into XDR routines.
-C: ANSI C mode.
-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). The -T option can be used in conjunction to produce a header file which supports RPC dispatch tables.
-i size: Generate inline code of size size.
-I: Generate code for inetd support in server (for SunOS 4.1).
-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 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 port monitors, like listen(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 -0.
-l: Compile into client-side stubs.
-L: Print server errors to syslog.
-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 initialization.
-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: Support multiple arguments and call-by-value.
-o outfile: Specify the name of the output file. If none is specified, standard output is used (-c, -h, -l, -m, -n, -s 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, visible, circuit_n, circuit_v, datagram_n, datagram_v, tcp, and udp (see rpc(3rpc) for the meanings associated with these classes). This option may be specified more than once. Note that the transports are chosen at run time and not at compile time.
-Sc: Generate sample client code that uses remote procedures.
-Sm: Generate makefile template.
-Ss: Generate sample client code that defines remote procedures.
-t: Compile into RPC dispatch table.
-T: Generate the code to support RPC dispatch tables.
-Y path: Find cpp at path path.

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.

Usage

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.

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 environment 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 not set, it creates server handles for all the visible transports from /etc/netconfig file. Note that 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 symbol, RPC_SVC_FG, can be defined at compilation time to make the server process run in the foreground.

The second synopsis provides special features which allow for the creation of more sophisticated RPC servers. These features include support for user provided ``#define''s 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 are described in the Example section. 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: 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.

Warnings

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 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.

References

cc(1)

Examples

The following example:

rpcgen -T prot.x

generates all 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