lwn.git/tools/net/sunrpc/xdrgen/generators, branch master

xdrgen: Implement pass-through lines in specifications

2026-01-29T14:48:33+00:00

XDR specification files can contain lines prefixed with '%' that pass through unchanged to generated output. Traditional rpcgen removes the '%' and emits the remainder verbatim, allowing direct insertion of C includes, pragma directives, or other language- specific content into the generated code. Until now, xdrgen silently discarded these lines during parsing. This prevented specifications from including necessary headers or preprocessor directives that might be required for the generated code to compile correctly. The grammar now captures pass-through lines instead of ignoring them. A new AST node type represents pass-through content, and the AST transformer strips the leading '%' character. Definition and source generators emit pass-through content in document order, preserving the original placement within the specification. This brings xdrgen closer to feature parity with traditional rpcgen while maintaining the existing document-order processing model. Existing generated xdrgen source code has been regenerated. Signed-off-by: Chuck Lever

xdrgen: Add enum value validation to generated decoders

2026-01-26T15:10:58+00:00

XDR enum decoders generated by xdrgen do not verify that incoming values are valid members of the enum. Incoming out-of-range values from malicious or buggy peers propagate through the system unchecked. Add validation logic to generated enum decoders using a switch statement that explicitly lists valid enumerator values. The compiler optimizes this to a simple range check when enum values are dense (contiguous), while correctly rejecting invalid values for sparse enums with gaps in their value ranges. The --no-enum-validation option on the source subcommand disables this validation when not needed. The minimum and maximum fields in _XdrEnum, which were previously unused placeholders for a range-based validation approach, have been removed since the switch-based validation handles both dense and sparse enums correctly. Because the new mechanism results in substantive changes to generated code, existing .x files are regenerated. Unrelated white space and semicolon changes in the generated code are due to recent commit 1c873a2fd110 ("xdrgen: Don't generate unnecessary semicolon") and commit 38c4df91242b ("xdrgen: Address some checkpatch whitespace complaints"). Reviewed-by: NeilBrown Signed-off-by: Chuck Lever

xdrgen: Emit a max_arg_sz macro

2026-01-26T15:10:58+00:00

struct svc_service has a .vs_xdrsize field that is filled in by servers for each of their RPC programs. This field is supposed to contain the size of the largest procedure argument in the RPC program. This value is also sometimes used to size network transport buffers. Currently, server implementations must manually calculate and hard-code this value, which is error-prone and requires updates when procedure arguments change. Update xdrgen to determine which procedure argument structure is largest, and emit a macro with a well-known name that contains the size of that structure. Server code then uses this macro when initializing the .vs_xdrsize field. For NLM version 4, xdrgen now emits: #define NLM4_MAX_ARGS_SZ (NLM4_nlm4_lockargs_sz) Signed-off-by: Chuck Lever

xdrgen: Implement short (16-bit) integer types

2026-01-26T15:10:58+00:00

"short" and "unsigned short" types are not defined in RFC 4506, but are supported by the rpcgen program. An upcoming protocol specification includes at least one "unsigned short" field, so xdrgen needs to implement support for these types. Signed-off-by: Chuck Lever

xdrgen: Emit the program number definition

2026-01-26T15:10:58+00:00

"xdrgen definitions" was not providing a definition of a symbolic constant for the RPC program number being defined. Signed-off-by: Chuck Lever

xdrgen: Fix struct prefix for typedef types in program wrappers

2026-01-26T15:10:58+00:00

The program templates for decoder/argument.j2 and encoder/result.j2 unconditionally add 'struct' prefix to all types. This is incorrect when an RPC protocol specification lists a typedef'd basic type or an enum as a procedure argument or result (e.g., NFSv2's fhandle or stat), resulting in compiler errors when building generated C code. Fixes: 4b132aacb076 ("tools: Add xdrgen") Signed-off-by: Chuck Lever

xdrgen: Generate "if" instead of "switch" for boolean union enumerators

2026-01-26T15:10:58+00:00

Eliminate this warning in code generated by xdrgen: fs/nfsd/nfs3xdr_gen.c:220:2: warning: switch condition has boolean value [-Wswitch-bool] 220 | switch (ptr->attributes_follow) { | ^ ~~~~~~~~~~~~~~~~~~~~~~ No more -Wswitch-bool warnings when compiling with W=1. The generated code is functionally equivalent but somewhat more idiomatic. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202511172336.Y75zj4v6-lkp@intel.com/ Signed-off-by: Chuck Lever

xdrgen: improve error reporting for invalid void declarations

2026-01-26T15:10:58+00:00

RFC 4506 defines void as a zero-length type that may appear only as union arms or as program argument/result types. It cannot be declared with an identifier, so constructs like "typedef void temp;" are not valid XDR. Previously, xdrgen raised a NotImplementedError when it encountered a void declaration in a typedef. Which was misleading, as the problem is an invalid RPC specification rather than missing functionality in xdrgen. This patch replaces the NotImplementedError for _XdrVoid in typedef handling with a clearer ValueError that specifies incorrect use of void in the XDR input, making it clear that the issue lies in the RPC specification being parsed. Signed-off-by: Khushal Chitturi Signed-off-by: Chuck Lever

xdrgen: handle _XdrString in union encoder/decoder

2025-11-25T14:09:42+00:00

Running xdrgen on xdrgen/tests/test.x fails when generating encoder or decoder functions for union members of type _XdrString. It was because _XdrString does not have a spec attribute like _XdrBasic, leading to AttributeError. This patch updates emit_union_case_spec_definition and emit_union_case_spec_decoder/encoder to handle _XdrString by assigning type_name = "char *" and avoiding referencing to spec. Testing: Fixed xdrgen tool was run on originally failing test file (tools/net/sunrpc/xdrgen/tests/test.x) and now completes without AttributeError. Modified xdrgen tool was also run against nfs4_1.x (Documentation/sunrpc/xdr/nfs4_1.x). The output header file matches with nfs4_1.h (include/linux/sunrpc/xdrgen/nfs4_1.h). This validates the patch for all XDR input files currently within the kernel. Changes since v2: - Moved the shebang to the first line - Removed SPDX header to match style of current xdrgen files Changes since v1: - Corrected email address in Signed-off-by. - Wrapped patch description lines to 72 characters. Signed-off-by: Khushal Chitturi Signed-off-by: Chuck Lever

xdrgen: Generalize/harden pathname construction

2025-11-25T14:09:42+00:00

Use Python's built-in Path constructor to find the Jinja templates. This provides better error checking, proper use of path component separators, and more reliable location of the template files. Signed-off-by: Chuck Lever