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
This fixes a potential race condition in select() if both a socket-fd
and non-socket fd trigger simultaneously to unblock this select.
In case of both fds, we use lwip's local thread semaphore, so we only
have to try return it (if it was taken/triggered more than once) when
we exit select().
Closes https://github.com/espressif/esp-idf/issues/8896
Calling "open" in CHECK_AND_CALL sets a perfectly correct errno.
There is no need to overwrite that with a value of ENOENT, since doing
so hides lower level errors like EIO.
Closes https://github.com/espressif/esp-idf/pull/8036
Adam Múdry
Guillaume Souchere
sonika.rathi
Tomáš Rohlínek
Alexey Lapshin
Martin Vychodil
Song Ruo Jing
zwx
Ivan Grokhotkov
Oliver Schmidt
David Cermak
morris
Vamshi Gajjela
hörbert
caixf
Jiacheng Guo
Cao Sen Miao
Omar Chebib