rpcgen - an RPC protocol compiler
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
rpcgen will generate a header file in
xdr.c, server-side stubs in
svc.c, and clientside
clnt.c. With the
-T option, it will also generate
the RPC dispatch table in
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
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
The server created can be started both by the port monitors (for example,
listen) or by itself. When it is started by a port monitor,
it creates servers only for the transport for which the file
0 was passed. The name of the transport must be specified
by setting up the environmental variable
TRANSPORT. When the server
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
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
rpcgen accepts the standard input.
The C preprocessor,
-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
Any line beginning with ‘
%’ is passed directly into the output file,
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
The following options are available:
#definedirective in the source. If no value is given, value is defined as
1. This option may be specified more than once.
Cdata-definitions (a header file).
-Toption can be used in conjunction to produce a header file which supports RPC dispatch tables.
-Iallows starting a service by either method.
120seconds after servicing a request before exiting. That interval can be changed using the
-Kflag. To create a server that exits immediately upon servicing a request,
0can be used. To create a server that never exits, the appropriate argument is
When monitoring for a server, some portmonitors, like lis_ten(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
rpcgen should be used with
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.
-t are used exclusively to generate
a particular type of file, while the options
-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 following example:
$ rpcgen -T prot.x
$ rpcgen -T prot.x
generates the five files:
The following example sends the C data-definitions (header file) to the standard output.
$ rpcgen -h prot.x
$ rpcgen -h prot.x
To send the test version of the
-DTEST, server side stubs for all the
transport belonging to the class
n to standard output, use:
To create the server side stubs for the transport indicated by netid
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