NAME¶
rpcgen - an RPC protocol compiler
SYNOPSIS¶
rpcgen infile
rpcgen [-D name[=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
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).
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 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 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
- 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 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
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
- 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 initialization.
- -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 code.
- -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
multiple 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 argument 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,
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
- Generate sample code to show the use of remote procedure
and how to bind to the server before calling the client side stubs
generated by rpcgen.
- -Sm
- Generate a sample Makefile which can be used for compiling
the application.
- -Ss
- Generate skeleton code for the remote procedures on the
server side. You would need to fill in the actual code for the remote
procedures.
- -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.
NOTES¶
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.
EXAMPLE¶
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
SEE ALSO¶
cc(1).