rpcgen - Remote Procedure Call (RPC) protocol compiler
rpcgen infile
[-D [name=value]] [-A] [-M] [-T] [-K secs] infile
[-L] [-M] -c | -h | -l | -m | -t | -Sc | -Ss [-o outfile] [infile]
-c | nettype [-o outfile] [infile]
-s | 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 EXAMPLES 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, cpp(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 .
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.
-a Generate all the files including sample code for client and
server side.
-b This generates code for the SunOS 4.1 style of RPC. This is the
default.
-c Compile into XDR routines.
-C Generate code in ANSI C. This option also generates code that
could be compiled with the C++ compiler.
-D name[=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.
-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 the AT&T
System V.4 UNIX utility listen, 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.
-L Server errors will be sent to syslog instead of stderr.
-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 thread-safe stubs. This alters the calling pattern of
client and server stubs so that storage for results is allocated
by the caller. Note that all components for a particular service
(stubs, client and service wrappers, etc.) must be built either
with or without the -M flag.
-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 . 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 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(3) for the meanings associated with these classes.
Note: BSD currently supports only the tcp and udp 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 .
-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.
The RPC Language does not support nesting of structures. As a workaround,
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.
The command
$ 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 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
cpp(1)
The -M option was first implemented in RedHat Linux, and was reimplemented
by Charles M. Hannum in NetBSD 1.6.
BSD April 3, 2001 BSD
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