Show error message when processes are killed by SIGSEGV/SIGILL/etc

[tgross35]

Related problem

Nushell currently does not print anything when a program is terminated by a signal:

> echo "int main() { asm("ud2"); }" out> sigill.c
> gcc sigill.c -o sigill.out
> ./sigill.out
> # *crickets*

> echo "int main() { int v = *((int *)0x0); }" out> sigsegv.c
> gcc sigsegv.c -o sigsegv.out
> ./sigsegv.out
> # *crickets*

This could be okay if you have the exit code displayed as part of the prompt, but if you don't then it looks like everything completed successfully.

By contrast, Bash tells you what went wrong:

$ ./sigill.out
Illegal instruction
$ ./sigsegv.out
Segmentation fault

Describe the solution you'd like

If a signal is the reason a program exits prematurely, print the associated comment so the user is aware of the problem (available at https://man7.org/linux/man-pages/man7/signal.7.html "Standard signals" table), or the same for the Windows equivalent. This can be retrieved on nix with ExitStatusExt::signal.

Describe alternatives you've considered

No response

Additional context and details

No response

[sholderbach]

Related challenge #12369 (not a duplicate)

@IanManske built some parts to potentially fix this in #12774 if I recall, I tried some things in #12370 but that did not work yet.

[sholderbach]

With #12774 we now properly pull out the signal but don't report the error as mentioned here (I think we had code for that at some point.) The $env.LAST_EXIT_CODE contains the signal value in negated form (which I think is not the conventional form. If I recall on Linux it is signal value + 128?)

[tgross35]

Does nushell not use std::process::Command? If so, the signal is available with .signal() under the ExitSignalExt trait (which calls libc::WIFSIGNALED(self.0).then(|| libc::WTERMSIG(self.0)) internally)