rpcgen
an RPC protocol compiler
see also :
cc
Synopsis
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
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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.
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
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.
see also
cc .