ESP32: Wifi logs cannot be configured

[bjoernQ]

Calling esp_wifi_internal_set_log_level or esp_wifi_internal_set_log_mod crashes immediately or cause crashes later (depending on when those are called) - so Wifi logs are never enabled on ESP32 (i.e. it works fine on ESP32C3)

Additionally there is a problem with VaList on ESP32 (or Xtensa in general) - that's why it's conditionally compiled only for ESP32C3 in log_writev

[MabezDev]

I've been applying this patch for vaarg support. I've never personally used vaargs, so it's quite possible this patch is buggy, or is missing some other steps?

[bjoernQ]

Awesome - will give it a try. Long time since I built the compiler myself the last time 😄

[MabezDev]

Just to be clear, it's already included in the esp-* branch patch set, so it should already be working.

[bjoernQ]

The va_list implementation seems to be fine since I can use it with some C code written myself and compiled with GCC. However, the va_list I get from the WiFi driver looks different. For now, I just print the format string on ESP32 which is better than having nothing. Still an interesting and valid issue so keep it open

No idea what I tested back then - here is an issue including a way to reproduce it easily: esp-rs/rust#177

[bjoernQ]

Unfortunately esp-rs/rust#171 doesn't fix this

[bjoernQ]

Alternatively, we could implement syslog, log_write and log_writev in C until a fix is available.

[karlri]

This is an ugly hack but it works. It's not very invasive because it replaces only exactly the function call that bugs out. Not likely woth a PR but if anyone is interested in trying it out, here it is (implemented for esp32 only): 8befe40