For C code the macros SIGRTMIN and SIGRTMAX provide these values. In
practice what looks like a constant is actually provided by a libc call.
So the Zig implementations are explicitly function calls.
glibc (and Musl) export a run-time minimum "real-time" signal number,
based on how many signals are reserved for internal implementation details
(generally threading). In practice, on Linux, sigrtmin() is 35 on glibc
with the older LinuxThread and 34 with the newer NPTL-based
implementation. Musl always returns 35. The maximum "real-time" signal
number is NSIG - 1 (64 on most Linux kernels, but 128 on MIPS).
When not linking a C Library, Zig can report the full range of "rt"
signals (none are reserved by Zig).
Fixes#21189
There were several bugs with the synchronization here; most notably an
ABA problem which was causing #21663. I fixed that and some other
issues, and took the opportunity to get rid of the `.seq_cst` orderings
from this file. I'm at least relatively sure my new orderings are correct.
Co-authored-by: achan1989 <achan1989@gmail.com>
Resolves: #21663
Dunno why the MIPS signal numbers are different, or why Zig had them
already special cased, but wrong.
We have the technology to test these constants. We should use it.
All the existing code that manipulates `ucontext_t` expects there to be a
glibc-compatible sigmask (1024-bit). The `ucontext_t` struct need to be
cleaned up so the glibc-dependent format is only used when linking
glibc/musl library, but that is a more involved change.
In practice, no Zig code looks at the sigset field contents, so it just
needs to be the right size.
By returning an initialized sigset (instead of taking the set as an output
parameter), these functions can be used to directly initialize the `mask`
parameter of a `Sigaction` instance.
When linking a libc, Zig should defer to the C library for sigset
operations. The pre-filled constants signal sets (empty_sigset,
filled_sigset) are not compatible with C library initialization, so remove
them and use the runtime `sigemptyset` and `sigfillset` methods to
initialize any sigset.
Unify the C library sigset_t and Linux native sigset_t and the accessor
operations.
Add tests that the various sigset_t operations are working. And clean up
existing tests a bit.
The kernel ABI sigset_t is smaller than the glibc one. Define the
right-sized sigset_t and fixup the sigaction() wrapper to leverage it.
The Sigaction wrapper here is not an ABI, so relax it (drop the "extern"
and the "restorer" fields), the existing `k_sigaction` is the ABI
sigaction struct.
Linux defines `sigset_t` with a c_ulong, so it can be 32-bit or 64-bit,
depending on the platform. This can make a difference on big-endian
systems.
Patch up `ucontext_t` so that this change doesn't impact its layout.
AFAICT, its currently the glibc layout.
Export the sigset_t ops (sigaddset, etc) from the C library. Don't rely
on the linux.zig defintions (which will be defined to use the kernel ABI).
Move Darwin sigset and NSIG declarations into darwin.zig. Remove
extraneous (?) sigaddset. The C library sigaddset can reject some signals
being added, so need to defer to it.
The last Intel Quark MCU was released in 2015. Quark was announced to be EOL in
2019, and stopped shipping entirely in 2022.
The OS tag was only meaningful for Intel's weird fork of Linux 3.8.7 with a
special ABI that differs from the regular i386 System V ABI; beyond that, the
CPU itself is just a plain old P54C (i586). We of course keep support for the
CPU itself, just not Intel's Linux fork.
