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Remove libc dependency on Windows by using Win32 to get env vars
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dpaoliello authored and Amanieu committed May 7, 2024
1 parent dee4c16 commit 8ce6875
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Showing 2 changed files with 43 additions and 14 deletions.
14 changes: 9 additions & 5 deletions .github/workflows/main.yml
Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ jobs:
steps:
- uses: actions/checkout@v4
- name: Install Rust
run: rustup update nightly && rustup default nightly
run: rustup update nightly --no-self-update && rustup default nightly
- run: ci/style.sh

docs:
Expand All @@ -25,7 +25,7 @@ jobs:
steps:
- uses: actions/checkout@v4
- name: Install Rust
run: rustup update nightly && rustup default nightly
run: rustup update nightly --no-self-update && rustup default nightly
- run: ci/dox.sh
env:
CI: 1
Expand All @@ -45,18 +45,22 @@ jobs:
steps:
- uses: actions/checkout@v4
- name: Install Rust
run: rustup update nightly && rustup default nightly
run: rustup update nightly --no-self-update && rustup default nightly
- run: cargo test --manifest-path crates/stdarch-verify/Cargo.toml

env_override:
name: Env Override
needs: [style]
runs-on: ubuntu-latest
runs-on: ${{ matrix.os }}
strategy:
matrix:
os: [ubuntu-latest, windows-latest]
steps:
- uses: actions/checkout@v4
- name: Install Rust
run: rustup update nightly && rustup default nightly
run: rustup update nightly --no-self-update && rustup default nightly
- run: RUST_STD_DETECT_UNSTABLE=avx cargo test --features=std_detect_env_override --manifest-path crates/std_detect/Cargo.toml env_override_no_avx
shell: bash

test:
needs: [style]
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43 changes: 34 additions & 9 deletions crates/std_detect/src/detect/cache.rs
Original file line number Diff line number Diff line change
Expand Up @@ -118,17 +118,42 @@ impl Cache {

cfg_if::cfg_if! {
if #[cfg(feature = "std_detect_env_override")] {
#[inline]
fn disable_features(disable: &[u8], value: &mut Initializer) {
if let Ok(disable) = core::str::from_utf8(disable) {
for v in disable.split(" ") {
let _ = super::Feature::from_str(v).map(|v| value.unset(v as u32));
}
}
}

#[inline]
fn initialize(mut value: Initializer) -> Initializer {
let env = unsafe {
libc::getenv(b"RUST_STD_DETECT_UNSTABLE\0".as_ptr() as *const libc::c_char)
};
if !env.is_null() {
let len = unsafe { libc::strlen(env) };
let env = unsafe { core::slice::from_raw_parts(env as *const u8, len) };
if let Ok(disable) = core::str::from_utf8(env) {
for v in disable.split(" ") {
let _ = super::Feature::from_str(v).map(|v| value.unset(v as u32));
const RUST_STD_DETECT_UNSTABLE: &[u8] = b"RUST_STD_DETECT_UNSTABLE\0";
cfg_if::cfg_if! {
if #[cfg(windows)] {
use alloc::vec;
#[link(name = "kernel32")]
extern "system" {
fn GetEnvironmentVariableA(name: *const u8, buffer: *mut u8, size: u32) -> u32;
}
let len = unsafe { GetEnvironmentVariableA(RUST_STD_DETECT_UNSTABLE.as_ptr(), core::ptr::null_mut(), 0) };
if len > 0 {
// +1 to include the null terminator.
let mut env = vec![0; len as usize + 1];
let len = unsafe { GetEnvironmentVariableA(RUST_STD_DETECT_UNSTABLE.as_ptr(), env.as_mut_ptr(), len + 1) };
if len > 0 {
disable_features(&env[..len as usize], &mut value);
}
}
} else {
let env = unsafe {
libc::getenv(RUST_STD_DETECT_UNSTABLE.as_ptr() as *const libc::c_char)
};
if !env.is_null() {
let len = unsafe { libc::strlen(env) };
let env = unsafe { core::slice::from_raw_parts(env as *const u8, len) };
disable_features(env, &mut value);
}
}
}
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