OpenBSD: add sensor structure and related constants by nalysius · Pull Request #5510 · rust-lang/libc

nalysius · 2026-09-07T13:27:01Z

Description

Add the structure sensor from sys/sensors.h and related SENSOR_* constants.

Source

https://github.com/openbsd/src/blob/e8afce5b5b9d68772098e66f10777f7b6abb530d/sys/sys/sensors.h

@rustbot label +stable-nominated

rustbot · 2026-09-07T13:27:05Z

Some changes occurred in an OpenBSD module

cc @semarie

semarie · 2026-09-07T13:37:57Z

+
+s! {
+    pub struct sensor {
+        pub desc: [u8; 32],


use the C type please. for example by using c_char instead of u8. it is important as not all architectures supported has the same signess.

View changes since the review

semarie · 2026-09-07T13:39:02Z

+        pub desc: [u8; 32],
+        pub timeval: timeval,
+        pub value: i64,
+        pub type_: c_int,


type and status are C enum (see c_enum! macro).

View changes since the review

nalysius · 2026-09-07T14:40:17Z

I updated based on your remarks, and I declared the sensors module that I forgot the first time.

semarie · 2026-09-07T15:37:29Z

+    }
+}
+
+pub const sensor_type_s: [&'static str; SENSOR_MAX_TYPES as usize + 1] = [


&str couldn't be used here. If I understood the error of the CI (local CI on OpenBSD), it is not FFI compatible: it means that the Rust layout for it is not the same than C, and so can't be used.

I am unsure how to resolv it. maybe just not export sensor_type_s.
else maybe @tgross35 will have some tips

View changes since the review

Would this be better?

pub const sensor_type_s: [*const c_char; SENSOR_MAX_TYPES as usize + 1] = [ cstr(b"temp\0"), cstr(b"fan\0"), /* ... */ ];

I think that definition should work, but I wouldn't bother adding it unless there's a usecase

I work on an i3 status bar project (which motivated this PR), and I use the sensor struct and the constants, but to be honest I don't use this one. I ported it because it was part of the sensor ecosystem in the header. I will remove it.

tgross35

LGTM but would also like @semarie's approval. Please squash also

View changes since this review

semarie · 2026-09-08T07:53:48Z

@tgross35 I will ping you once it is fine on my side. For now I have CI issues that I need to look at (if related to these changes or not). Thanks.

semarie

After running the CI on it, there are several points to address.

And outside the commentaries, libc-test/build/main.rs should also be adapted:

include sys/sensors.h in the headers included for testing the C values
register the field rename for sensor->type_
declare the enums

For this part, I have the following diff you could reuse:

diff --git a/libc-test/build/main.rs b/libc-test/build/main.rs
index 6a2ff1252..bb0e47ee1 100755
--- a/libc-test/build/main.rs
+++ b/libc-test/build/main.rs
@@ -411,6 +411,7 @@ fn test_openbsd(t: &Target) {
         "wchar.h",
         "ctype.h",
         "dirent.h",
+        "sys/sensors.h",
         "sys/socket.h",
         (x86_64, "machine/fpu.h"),
         "net/if.h",
@@ -506,6 +507,10 @@ fn test_openbsd(t: &Target) {

             "sa_sigaction" if struct_ == "sigaction" => "sa_handler".to_string(),

+            // Field is named `type` in C but that is a Rust keyword,
+            // so these fields are translated to `type_` in the bindings.
+            "type_" if struct_ == "sensor" => "type".to_string(),
+
             _ => return None,
         };
         Some(replacement)
@@ -526,6 +531,13 @@ fn test_openbsd(t: &Target) {
     cfg.rename_struct_ty(|ty| ty.ends_with("_t").then_some(ty.to_string()));
     cfg.rename_union_ty(|ty| ty.ends_with("_t").then_some(ty.to_string()));

+    cfg.alias_is_c_enum(move |ty| {
+        match ty {
+            "sensor_type" | "sensor_status" => true,
+            _ => false,
+        }
+    });
+
     cfg.skip_struct(move |struct_| {
         match struct_.ident() {
             // Extern types

View changes since this review

semarie · 2026-09-08T11:32:41Z

+SENSOR_STATUS_UNKNOWN
+SENSOR_STATUS_UNSPEC
+SENSOR_STATUS_WARN
+SENSOR_TYPE_ACCEL


it is not the exported name: SENSOR_ACCEL is the right one.
same for all SENSOR_TYPE_* names.

semarie · 2026-09-08T11:33:24Z

+SENSOR_FINVALID
+SENSOR_FUNKNOWN
+SENSOR_MAX_TYPES
+SENSOR_STATUS_CRIT


it is not the exported name: SENSOR_S_CRIT is the right one.
same for all SENSOR_STATUS_* names.

semarie · 2026-09-08T11:35:53Z

+SENSOR_TYPE_TEMP
+SENSOR_TYPE_TIMEDELTA
+SENSOR_TYPE_VELOCITY
+SENSOR_TYPE_VOLTSAC


SENSOR_TYPE_VOLTSAC -> SENSOR_VOLTS_AC

semarie · 2026-09-08T11:36:03Z

+SENSOR_TYPE_TIMEDELTA
+SENSOR_TYPE_VELOCITY
+SENSOR_TYPE_VOLTSAC
+SENSOR_TYPE_VOLTSDC


SENSOR_TYPE_VOLTSDC -> SENSOR_VOLTS_DC

nalysius · 2026-09-09T09:10:29Z

Most issues came from when I moved the constants to enums, I should have been more careful, sorry. Thank you for the main.rs patch.

nalysius · 2026-09-09T09:27:41Z

The CI fails without any info, the error seems to be empty. Am I missing something?

semarie · 2026-09-09T09:32:16Z

it is failing due to style check: https://github.com/rust-lang/libc/actions/runs/34332816559/job/102405155919?pr=5510

nalysius · 2026-09-09T10:07:14Z

I discovered the script ci/style.py. I can't run it completely on OpenBSD nor in an Alpine VM since it requires +nightly and glibc, but at least the formatting worked. It should be better this time.

semarie

LGTM but please squash the commits
Cc @tgross35

View changes since this review

The structure sensor and the SENSOR_* constants have been added, as well as the sensor_status and sensor_type enumerations. Ref: https://github.com/openbsd/src/blob/e8afce5b5b9d68772098e66f10777f7b6abb530d/sys/sys/sensors.h

rustbot · 2026-09-09T11:54:41Z

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.

nalysius · 2026-09-09T11:55:42Z

Commits have been squashed. Thanks for your support in this PR.

rustbot added O-bsd S-waiting-on-review stable-nominated This PR should be considered for cherry-pick to libc's stable release branch labels Sep 7, 2026

nalysius force-pushed the add-openbsd-sensors-sensor branch from e4b9467 to ad7c2d5 Compare September 7, 2026 13:29

semarie suggested changes Sep 7, 2026

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nalysius requested a review from semarie September 7, 2026 15:00

semarie suggested changes Sep 7, 2026

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tgross35 approved these changes Sep 8, 2026

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semarie suggested changes Sep 8, 2026

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semarie approved these changes Sep 9, 2026

View reviewed changes

openbsd: add sensor structure and related items

b4769f4

The structure sensor and the SENSOR_* constants have been added, as well as the sensor_status and sensor_type enumerations. Ref: https://github.com/openbsd/src/blob/e8afce5b5b9d68772098e66f10777f7b6abb530d/sys/sys/sensors.h

nalysius force-pushed the add-openbsd-sensors-sensor branch from 74cde7d to b4769f4 Compare September 9, 2026 11:54

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nalysius commented Sep 7, 2026

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nalysius commented Sep 7, 2026

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semarie commented Sep 8, 2026

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nalysius commented Sep 9, 2026

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semarie commented Sep 9, 2026

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