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 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:
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 0b
code that could be compiled with the C++ compiler. This is the default.
-k #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 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 0c
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-c, -h, -l, -m,
-n, -s, -s -sand -t modes only).
-s nettypenetpath, 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.
The RPC Language does not support nesting of structures. As a work-around, structures can be declared at the toplevel, 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.
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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
$ rpcgen -s datagram_n -DTEST prot.x-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
$ rpcgen -n tcp -o prot_svc.c prot.xtcp, use:
cc(1) .
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