Regression: Interrupted system call in CI about crystal

[HertzDevil]

It looks like none of the bindings define LibC::SA_RESTART, so maybe it's best to use sigaction there only when {{ flag?(:solaris) }} is true, unless someone could find the correct values on all supported systems?

[ysbaddaden]

@straight-shoota @HertzDevil the solaris PR changes the signal handler to use sigaction(2) instead of signal(2) and we get interrupted syscalls 🤔

https://github.com/crystal-lang/crystal/pull/14343/files#diff-defc0d953337c02ce30da590dbf3a9f0daa536c9fae6ad381e2af06ffab1eb60

[ysbaddaden]

Reading the signal(7) man page, we might just need to add the SA_RESTART flag?

[ysbaddaden]

From the signal(2) man page:

The situation on Linux is as follows:

• The kernel's signal() system call provides System V semantics.
• By default, in glibc 2 and later, the signal() wrapper function does not invoke the kernel system call. Instead, it calls sigaction(2) using flags that supply BSD semantics.

The BSD semantics are equivalent to calling sigaction(2) with the following flags:

sa.sa_flags = SA_RESTART;

[ysbaddaden]

I pushed without checking 🤦

Luckily, I have a copy of many /usr/include on my computer from when I wrote the posix shard. They date from many years back, but constants for syscalls are unlikely to ever change.

That being said, I wish I could just say "I want SA_RESTART please figure its actual value".

[straight-shoota]

but constants for syscalls are unlikely to ever change.

Yeah, that would lead to very surprising results 😆