Support sigaction with SIG_DFL and SA_SIGINFO.

[tmds]

Fixes#55645

@rolfbjarne@lambdageek@stephentoub ptal

[stephentoub]

@janvorli, could you review this one as well? Thanks!

[janvorli]

LGTM modulo the nit.

[janvorli]

A nit - can you please add ( ) to explicitly express the precedence in all the composite conditions? It is a preferred style in this codebase. Like this:

return ((&action->sa_handler == (void*)&action->sa_sigaction) || !IsSaSigInfo(action)) &&
(action->sa_handler == SIG_DFL));

[danmoseley]

Linux failure is a SIGABRT in the Http tests on Linux. I am not sure how to resolve the frames:

0:000> kp
# Child-SP RetAddr Call Site
00 00007f4b`40cdf430 00007f4b`44cd294d libc_2_31!gsignal+0x145
01 00007f4b`40cdf550 00007f4b`2eedf479 (T) libc_2_31!abort+0x1df
02 00007f4b`40cdf680 00007f4b`2eecd109 libmsquic!MsQuicOpenVersion+0x607c4
03 00007f4b`40cdf690 00007f4b`2eea1a60 libmsquic!MsQuicOpenVersion+0x4e459
04 00007f4b`40cdf6c0 00007f4b`2ee9a3c5 libmsquic!MsQuicOpenVersion+0x22db0
05 00007f4b`40cdf6d0 00007f4a`cb499e12 libmsquic!MsQuicOpenVersion+0x1b715
06 00007f4b`40cdf7f0 00000000`00000000 0x00007f4a`cb499e12

Seems unlikely it is related.

[danmoseley]

Because this is breaking Xamarin iOS, and tomorrow is Preview 7 sync, I will merge this and @tmds can perhaps fix the code formatting separately. I hope that is OK.

I am assuming the Http crash is not related.

[danmoseley]

Oh, I didn't see that one of the arm64 configs timed out. I'll rerun that.

[ghost]

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[steveisok]

Github and azdo are out of sync. Looks like the build has finished successfully.