include/errno.h: skip set_errno in interrupt context

[masc2008]

Summary

• Why: errno is defined as a per-thread value. When set_errno() is called from an interrupt handler, it currently modifies the interrupted task's errno, which violates POSIX semantics because the interrupted task did not request the failing operation.
• What: Add an up_interrupt_context() guard inside the set_errno() macro so that the assignment is skipped when running in an interrupt handler.
• How: Include <nuttx/irq.h> and wrap the errno = (int)(e) assignment with if (!up_interrupt_context()).

Impact

• Is new feature added? Is existing feature changed? NO
• Impact on user (will user need to adapt to change)? NO
• Impact on build (will build process change)? NO
• Impact on hardware (will arch(s) / board(s) / driver(s) change)? NO
• Impact on documentation (is update required / provided)? NO
• Impact on security (any sort of implications)? NO
• Impact on compatibility (backward/forward/interoperability)? NO
• Anything else to consider or add? This is a defensive fix that prevents silent corruption of a task's errno by ISR code.

Testing

I confirm that changes are verified on local setup and works as intended:

• Build Host(s): Linux x86_64, GCC 13.4.0 (arm-none-eabi)
• Target(s): arm/qemu-armv7a:full

Testing logs after change:

there is no log when do it, I tested this under qemu-armv7a and BES chip.

[ankohuu]

Do we need to add an ASSERT and fix already?

[masc2008]

fixed compile error.

[masc2008]

Do we need to add an ASSERT and fix already?

some person may have already called some libc function like in interrupt context, it's not a good practice. But I don't think it's good to do such break change. let's start from a small step.

[linguini1]

Just an FYI, since we are moving to 13.0.0 next, this would be a good time for the breaking change of adding an assertion.