rpcgen - an RPC protocol compiler [=value]] [-T] [-K secs] infile ] infile [-o outfile] infile [-o outfile] infilerpcgen 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 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:
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.
- pointers to the service routine corresponding to that procedure,
- a pointer to the input and output arguments
- the size of these routines
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 secs 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. 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 -1. -l -m -n netid -N -o outfile -c, -h, -l, -m, -n, -s, -sSc, -sSs and -t modes only). -s nettype netpath, visible, 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.
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.
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.
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:
To create the server side stubs for the transport indicated by netid tcp, use:
cc(1).