linux: complete `siginfo_t` definition by dybucc · Pull Request #5345 · rust-lang/libc

dybucc · 2026-07-31T15:31:04Z

Description

Completes the siginfo_t definition under Linux targets. Closes #716.

See the patch messages for details on each of the GNU targets, uClibc
targets and musl targets.

Checklist

Relevant tests in libc-test/semver have been updated
Commit messages permalink to headers for added or changed API
Placeholder or unstable values like *LAST or *MAX have the
standard doc comment
Tested locally (cargo test -p libc-test --target mytarget);
especially relevant for platforms that may not be checked in CI

@rustbot label +stable-nominated

tgross35 · 2026-08-04T03:06:36Z

Would you mind using this as an opportunity to move signifo_t to src/new? At least on glibc, that should make things a lot easier with less duplication. No need to be perfect with siginfo-arch.h since that's tricky to replicate in Rust, cfg is fine.

Also fyi, @xtqqczze found https://github.com/sailfishos-mirror/glibc as a mirror for glibc that's much easier to search and less flaky, that's fine to link (as is sourceware, of course).

tgross35 · 2026-08-04T04:13:39Z

There will be quite a bit less to review after that, so will hold off taking a closer look. Let me know if you need help figuring out the module structure.

@rustbot author

rustbot · 2026-08-04T04:13:43Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

Replace references to `siginfo_t` in the regular repository layout with a crate-relative path that uses the reexport from the `new` module. This allows the next few patches to all work as individual revisions.

Replace alignment/padding fields with a one-to-one definition as that used upstream. These have been incorporated as definitions in the `new` module to avoid huge repetition across target triples without overrides. The glibc definitions are mostly the same across target architectures except for MIPS, SPARC and x86. x86 is confusing because there's only an override when running under x86_64 and compiling for x32. I'm not sure how Rust handles this, so the `#[path]`-redirected files for that architecture are the same as the generic ones. See [^1] for the generic file and the following list for the architecture-specific overrides. - `mips`: <https://github.com/sailfishos-mirror/glibc/blob/4a07bb292f921c10e71fbf48c4a7f44391feb06c/sysdeps/unix/sysv/linux/mips/bits/siginfo-arch.h> - `sparc`: <https://github.com/sailfishos-mirror/glibc/blob/4a07bb292f921c10e71fbf48c4a7f44391feb06c/sysdeps/unix/sysv/linux/sparc/bits/siginfo-arch.h> - `x86`: <https://github.com/sailfishos-mirror/glibc/blob/4a07bb292f921c10e71fbf48c4a7f44391feb06c/sysdeps/unix/sysv/linux/x86/bits/siginfo-arch.h> [^1]: <https://github.com/sailfishos-mirror/glibc/blob/4a07bb292f921c10e71fbf48c4a7f44391feb06c/sysdeps/unix/sysv/linux/bits/types/siginfo_t.h>

Remove older bindings to `siginfo_t` using dummy fields instead of the upstream `union`. This follows from the patch providing a full definition for glibc bindings. Add reexports for `siginfo_t` under the `new` module. This has required renaming the reexport for the `nptl` module as it also contains a `bits` module of the same name as the `bits::types::siginfo_t` module path under `sysdeps`.

Replace alignment/padding fields with a mirrored definition of the upstream `union`. See [^1] for details. [^1]: <https://github.com/kraj/musl/blob/a42e9dee266f398026a33d0793c66225c7997755/include/signal.h>

Remove older bindings to `siginfo_t` using dummy fields instead of the upstream `union`. This follows from the patch providing a full definition for musl bindings. Add modified bindings under `new`.

Replace alignment/padding dummy fields with a mirrored definition fitting that of upstream's `union`. uClibc supports targets for which we have no support in Rust. No architecture-specific definition has been provided for those. See [^1] for details on the generic definition and [^2] for details on the MIPS definition. [^1]: <https://github.com/wbx-github/uclibc-ng/blob/60d8e8c0cb9be8a241f6f2645daba260c8aec33c/libc/sysdeps/linux/common/bits/siginfo.h> [^2]: <https://github.com/wbx-github/uclibc-ng/blob/60d8e8c0cb9be8a241f6f2645daba260c8aec33c/libc/sysdeps/linux/mips/bits/siginfo.h>

Remove older bindings to `siginfo_t` using dummy fields instead of the upstream `union`. This follows from the patch providing a full definition for uClibc bindings. Add modified bindings to `new` module.

rustbot · 2026-09-01T10:33:51Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

dybucc · 2026-09-01T10:35:36Z

@rustbot ready

tgross35

Looks great, thank you!

Happy to merge this now since it's an improvement, but would you be able to do a followup removing siginfo_t skips in libc-test/build/main.rs? I don't know that all can be removed but looks like possibly a couple.

View changes since this review

Replace references to `siginfo_t` in the regular repository layout with a crate-relative path that uses the reexport from the `new` module. This allows the next few patches to all work as individual revisions. (backport <rust-lang#5345>) (cherry picked from commit aa478e6)

Replace alignment/padding fields with a one-to-one definition as that used upstream. These have been incorporated as definitions in the `new` module to avoid huge repetition across target triples without overrides. The glibc definitions are mostly the same across target architectures except for MIPS, SPARC and x86. x86 is confusing because there's only an override when running under x86_64 and compiling for x32. I'm not sure how Rust handles this, so the `#[path]`-redirected files for that architecture are the same as the generic ones. See [^1] for the generic file and the following list for the architecture-specific overrides. - `mips`: <https://github.com/sailfishos-mirror/glibc/blob/4a07bb292f921c10e71fbf48c4a7f44391feb06c/sysdeps/unix/sysv/linux/mips/bits/siginfo-arch.h> - `sparc`: <https://github.com/sailfishos-mirror/glibc/blob/4a07bb292f921c10e71fbf48c4a7f44391feb06c/sysdeps/unix/sysv/linux/sparc/bits/siginfo-arch.h> - `x86`: <https://github.com/sailfishos-mirror/glibc/blob/4a07bb292f921c10e71fbf48c4a7f44391feb06c/sysdeps/unix/sysv/linux/x86/bits/siginfo-arch.h> [^1]: <https://github.com/sailfishos-mirror/glibc/blob/4a07bb292f921c10e71fbf48c4a7f44391feb06c/sysdeps/unix/sysv/linux/bits/types/siginfo_t.h> (backport <rust-lang#5345>) (cherry picked from commit 4b355bd) [ Needed to adjust the body of si_int for the cherry pick since on libc-0.2, sigval is still a struct - Trevor ]

Remove older bindings to `siginfo_t` using dummy fields instead of the upstream `union`. This follows from the patch providing a full definition for glibc bindings. Add reexports for `siginfo_t` under the `new` module. This has required renaming the reexport for the `nptl` module as it also contains a `bits` module of the same name as the `bits::types::siginfo_t` module path under `sysdeps`. (backport <rust-lang#5345>) (cherry picked from commit 404da0e)

Replace alignment/padding fields with a mirrored definition of the upstream `union`. See [^1] for details. [^1]: <https://github.com/kraj/musl/blob/a42e9dee266f398026a33d0793c66225c7997755/include/signal.h> (backport <rust-lang#5345>) (cherry picked from commit 5bea5fb) [ Needed to adjust the body of si_int for the cherry pick since on libc-0.2, sigval is still a struct - Trevor ]

Remove older bindings to `siginfo_t` using dummy fields instead of the upstream `union`. This follows from the patch providing a full definition for musl bindings. Add modified bindings under `new`. (backport <rust-lang#5345>) (cherry picked from commit 539ecdd)

Replace alignment/padding dummy fields with a mirrored definition fitting that of upstream's `union`. uClibc supports targets for which we have no support in Rust. No architecture-specific definition has been provided for those. See [^1] for details on the generic definition and [^2] for details on the MIPS definition. [^1]: <https://github.com/wbx-github/uclibc-ng/blob/60d8e8c0cb9be8a241f6f2645daba260c8aec33c/libc/sysdeps/linux/common/bits/siginfo.h> [^2]: <https://github.com/wbx-github/uclibc-ng/blob/60d8e8c0cb9be8a241f6f2645daba260c8aec33c/libc/sysdeps/linux/mips/bits/siginfo.h> (backport <rust-lang#5345>) (cherry picked from commit 11a1a64) [ Needed to adjust the body of si_int for the cherry pick since on libc-0.2, sigval is still a struct - Trevor ]

Remove older bindings to `siginfo_t` using dummy fields instead of the upstream `union`. This follows from the patch providing a full definition for uClibc bindings. Add modified bindings to `new` module. (backport <rust-lang#5345>) (cherry picked from commit ae20d43)

rustbot added O-arm O-gnu O-linux O-linux-like O-mips O-musl O-powerpc O-riscv O-sparc O-unix O-x86 S-waiting-on-review stable-nominated This PR should be considered for cherry-pick to libc's stable release branch labels Jul 31, 2026

dybucc changed the title ~~Linux: complete siginfo_t definition~~ linux: complete siginfo_t definition Jul 31, 2026

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dybucc force-pushed the linux-siginfo_t-tweaks branch from a6ba6f4 to bd71182 Compare August 5, 2026 06:49

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dybucc force-pushed the linux-siginfo_t-tweaks branch 7 times, most recently from b02986c to 08192fa Compare August 5, 2026 15:18

dybucc force-pushed the linux-siginfo_t-tweaks branch from 3b24df9 to 5a893ac Compare September 1, 2026 08:27

dybucc added 7 commits September 1, 2026 12:12

linux: ensure siginfo_t uses mod new bindings

559920b

Replace references to `siginfo_t` in the regular repository layout with a crate-relative path that uses the reexport from the `new` module. This allows the next few patches to all work as individual revisions.

linux(musl): complete siginfo_t definition

3400f92

Replace alignment/padding fields with a mirrored definition of the upstream `union`. See [^1] for details. [^1]: <https://github.com/kraj/musl/blob/a42e9dee266f398026a33d0793c66225c7997755/include/signal.h>

linux(musl): replace older siginfo_t bindings

8cf50d4

Remove older bindings to `siginfo_t` using dummy fields instead of the upstream `union`. This follows from the patch providing a full definition for musl bindings. Add modified bindings under `new`.

linux(uclibc): replace older siginfo_t bindings

627a3e4

Remove older bindings to `siginfo_t` using dummy fields instead of the upstream `union`. This follows from the patch providing a full definition for uClibc bindings. Add modified bindings to `new` module.

dybucc force-pushed the linux-siginfo_t-tweaks branch from 5a893ac to c05354f Compare September 1, 2026 10:33

dybucc force-pushed the linux-siginfo_t-tweaks branch from c05354f to 627a3e4 Compare September 1, 2026 10:33

rustbot added S-waiting-on-review and removed S-waiting-on-author labels Sep 1, 2026

tgross35 approved these changes Sep 3, 2026

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tgross35 added this pull request to the merge queue Sep 3, 2026

Merged via the queue into rust-lang:main with commit ae20d43 Sep 3, 2026
58 checks passed

rustbot removed the S-waiting-on-review label Sep 3, 2026

rustbot mentioned this pull request Sep 3, 2026

Use Padding and make public padding fields private #5444

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tgross35 mentioned this pull request Sep 4, 2026

[0.2] Backports #5462

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tgross35 added stable-applied This PR has been cherry-picked to libc's stable release branch and removed stable-nominated This PR should be considered for cherry-pick to libc's stable release branch labels Sep 4, 2026

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