Files
esp-idf/components/freertos/FreeRTOS-Kernel
Guillaume Souchere 9835daba70 feat(freertos/vfs): add Linux cooperative syscall dispatch with VFS FD registration
Rework the syscall interposition architecture so FreeRTOS works
standalone (without VFS) and VFS optionally overrides with strong
symbols.  All kernel FDs are registered with VFS via
esp_vfs_register_fd_with_local_fd, so the application only sees
VFS-allocated FD numbers, preventing numerical collisions between
kernel FDs and VFS-internal FD slots.

FreeRTOS side:
- Create linux_port_coop_internal.h with LINUX_COOP_IO_LOOP,
  LINUX_COOP_RESOLVE, linux_coop_yield and FD state table functions
- Export cooperative I/O primitives (freertos_linux_coop_read/write/
  open/close/fcntl/select/pread/pwrite/readv/writev/recv/send/
  recvfrom/sendto/recvmsg/sendmsg/connect/accept/pselect/poll/
  socket/socketpair/pipe/pipe2/dup/dup2/syscalls_init)
- Define weak POSIX symbols calling through to the cooperative
  primitives; keep nanosleep/sleep/usleep as strong (not FD-related)
- Refactor freertos_linux_coop_syscalls.h into a pure public API header

VFS side:
- Register the Linux host FS with esp_vfs_register_fs_with_id() as a
  proper VFS driver; register stdin/stdout/stderr at init (priority 99)
- Rewrite vfs_linux.c with strong POSIX symbols dispatching through
  esp_vfs_*
- Add strong overrides for FD-creating syscalls (open, pipe, pipe2,
  socket, socketpair, dup, dup2, accept) that register returned FDs
  with VFS
- Add strong overrides for FD-translating syscalls (readv, writev,
  recv, send, recvfrom, sendto, recvmsg, sendmsg, connect, pselect,
  poll) that translate VFS FD to kernel FD
- Delete vfs_coop_syscalls.c (absorbed into FreeRTOS weak + VFS strong)
- Update CMakeLists.txt: remove vfs_coop_syscalls.c, add linker hook
2026-06-04 11:36:34 +02:00
..

Getting started

This repository contains FreeRTOS kernel source/header files and kernel ports only. This repository is referenced as a submodule in FreeRTOS/FreeRTOS repository, which contains pre-configured demo application projects under FreeRTOS/Demo directory.

The easiest way to use FreeRTOS is to start with one of the pre-configured demo application projects. That way you will have the correct FreeRTOS source files included, and the correct include paths configured. Once a demo application is building and executing you can remove the demo application files, and start to add in your own application source files. See the FreeRTOS Kernel Quick Start Guide for detailed instructions and other useful links.

Additionally, for FreeRTOS kernel feature information refer to the Developer Documentation, and API Reference.

Getting help

If you have any questions or need assistance troubleshooting your FreeRTOS project, we have an active community that can help on the FreeRTOS Community Support Forum.

Cloning this repository

To clone using HTTPS:

git clone https://github.com/FreeRTOS/FreeRTOS-Kernel.git

Using SSH:

git clone git@github.com:FreeRTOS/FreeRTOS-Kernel.git

Repository structure

  • The root of this repository contains the three files that are common to every port - list.c, queue.c and tasks.c. The kernel is contained within these three files. croutine.c implements the optional co-routine functionality - which is normally only used on very memory limited systems.

  • The ./portable directory contains the files that are specific to a particular microcontroller and/or compiler. See the readme file in the ./portable directory for more information.

  • The ./include directory contains the real time kernel header files.

Code Formatting

FreeRTOS files are formatted using the "uncrustify" tool. The configuration file used by uncrustify can be found in the FreeRTOS/FreeRTOS repository.

Spelling

lexicon.txt contains words that are not traditionally found in an English dictionary. It is used by the spellchecker to verify the various jargon, variable names, and other odd words used in the FreeRTOS code base. If your pull request fails to pass the spelling and you believe this is a mistake, then add the word to lexicon.txt. Note that only the FreeRTOS Kernel source files are checked for proper spelling, the portable section is ignored.