The byte size of a variable-length opaque is conveyed in an unsigned
integer. If there is a specified maximum size, that is included in
the type's widths list.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The XDR width for a fixed-length opaque is the byte size of the
opaque rounded up to the next XDR_UNIT, divided by XDR_UNIT.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
RFC 4506 says that an XDR enum is represented as a signed integer
on the wire; thus its width is 1 XDR_UNIT.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The generic parts of the RPC layer need to know the widths (in
XDR_UNIT increments) of the XDR data types defined for each
protocol.
As a first step, add dictionaries to keep track of the symbolic and
actual maximum XDR width of XDR types.
This makes it straightforward to look up the width of a type by its
name. The built-in dictionaries are pre-loaded with the widths of
the built-in XDR types as defined in RFC 4506.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
In order to compute the numeric on-the-wire width of XDR types,
xdrgen needs to keep track of the numeric value of constants that
are defined in the input specification so it can perform
calculations with those values.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Clean up: Add a __post_init__ function to the data classes that
need to update the "structs" and "pass_by_reference" sets.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
I misread RFC 4506. The built-in data type is called simply
"string", as there is no fixed-length variety.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Clean up: Make both arms of the type_specifier AST transformer
match. No behavior change is expected.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
To use xdrgen in Makefiles, it needs to exit with a zero status if
the compilation worked. Otherwise the make command fails with an
error.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
I noticed that "xdrgen source" reorders the procedure encoder and
decoder functions every time it is run. I would prefer that the
generated code be more deterministic: it enables a reader to better
see exactly what has changed between runs of the tool.
The problem is that Python sets are not ordered. I use a Python set
to ensure that, when multiple procedures use a particular argument or
result type, the encoder/decoder for that type is emitted only once.
Sets aren't ordered, but I can use Python dictionaries for this
purpose to ensure the procedure functions are always emitted in the
same order if the .x file does not change.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
'typedef opaque yada<XYZ>' should use xdrgen's built-in opaque
encoder and decoder, to enable better compiler optimization.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
xdr_stream_encode_u32() returns XDR_UNIT on success.
xdr_stream_decode_u32() returns zero or -EMSGSIZE, but never
XDR_UNIT.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Add a Python-based tool for translating XDR specifications into XDR
encoder and decoder functions written in the Linux kernel's C coding
style. The generator attempts to match the usual C coding style of
the Linux kernel's SunRPC consumers.
This approach is similar to the netlink code generator in
tools/net/ynl .
The maintainability benefits of machine-generated XDR code include:
- Stronger type checking
- Reduces the number of bugs introduced by human error
- Makes the XDR code easier to audit and analyze
- Enables rapid prototyping of new RPC-based protocols
- Hardens the layering between protocol logic and marshaling
- Makes it easier to add observability on demand
- Unit tests might be built for both the tool and (automatically)
for the generated code
In addition, converting the XDR layer to use memory-safe languages
such as Rust will be easier if much of the code can be converted
automatically.
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
