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gerrit.openbmc.org / openbmc / libcper / 8d47a37fe1afa2bcdefc862b91ae22b515b9541c
commit8d47a37fe1afa2bcdefc862b91ae22b515b9541c[log] [tgz]
authorEd Tanous <etanous@nvidia.com>Wed Mar 05 15:55:36 2025 -0800
committerEd Tanous <ed@tanous.net>Thu Mar 06 22:54:20 2025 +0000
tree88118313d8bb8fe363bc5dd63d3d8e8ff9e4e445
parenta6730793584537a67264b2f8a5f5be9187a7a6ef [diff]
Add buffer based decoders

libcper currently supports an API that reads from a FILE* type.  This
is fine for some use cases, but in the majority of use cases where we're
embedding, libcper would prefer to not be opinionated about how a file
came to be.

This patchset adds two new public methods, cper_buf_to_ir and
cper_buf_single_section_to_ir, which function like the existing non _buf
versions of these.

As a stepping stone, these are implemented as a fmemopen to get a FILE*
object to be passed to the underlying functions.  This allows us in a
future commit to start removing the FILE* interfaces internally and pass
the buffer directly throughout libcper.

Change-Id: I9fb7ab46b8ba7bfef7bd71ec37f2b55054b09d72
Signed-off-by: Ed Tanous <etanous@nvidia.com>
2 files changed
tree: 88118313d8bb8fe363bc5dd63d3d8e8ff9e4e445
  1. cli-app/
  2. docs/
  3. examples/
  4. generator/
  5. include/
  6. sections/
  7. specification/
  8. subprojects/
  9. tests/
  10. .clang-format
  11. .clang-tidy
  12. .gitignore
  13. base64.c
  14. common-utils.c
  15. cper-parse.c
  16. cper-parse.i
  17. cper-utils.c
  18. Cper.c
  19. ir-parse.c
  20. json-schema.c
  21. LICENSE
  22. meson.build
  23. meson.options
  24. OWNERS
  25. README.md
README.md

CPER JSON Representation & Conversion Library

This repository specifies a structure for representing UEFI CPER records (as described in UEFI Specification Appendix N) in a human-readable JSON format, in addition to a library which can readily convert back and forth between the standard CPER binary format and the specified structured JSON.

Prerequisites

Before building this library and its associated tools, you must have meson (>=1.1.1)

Building

This project uses Meson (>=1.1.1). To build for native architecture, simply run:

meson setup build
ninja -C build

Usage

This project comes with several binaries to help you deal with CPER binary and CPER-JSON. The first of these is cper-convert, which is a command line tool that can be found in build/. With this, you can convert to and from CPER and CPER-JSON through the command line. An example usage scenario is below:

cper-convert to-cper samples/cper-json-test-arm.json --out cper.dump
cper-convert to-json cper.generated.dump

Another tool bundled with this repository is cper-generate, found in build/. This allows you to generate pseudo-random valid CPER records with sections of specified types for testing purposes. An example use of the program is below:

cper-generate --out cper.generated.dump --sections generic ia32x64

Help for both of these tools can be accessed through using the --help flag in isolation.

Finally, a static library containing symbols for converting CPER and CPER-JSON between an intermediate JSON format can be found generated at lib/libcper-parse.a. This contains the following useful library symbols:

json_object* cper_to_ir(FILE* cper_file);
void ir_to_cper(json_object* ir, FILE* out);

Specification

The specification for this project's CPER-JSON format can be found in specification/, defined in both JSON Schema format and also as a LaTeX document. Specification for the CPER binary format can be found in UEFI Specification Appendix N (2021/03/18).

Usage Examples

This library is utilised in a proof of concept displaying CPER communication between a SatMC and OpenBMC board, including a conversion into CPER JSON for logging that utilises this library. You can find information on how to reproduce the prototype at the scripts repository, and example usage of the library itself at the pldm repository.