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Merged
merged 7 commits into from
Sep 23, 2025
Merged

Add windows_legacy opt-in backend #724

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8a96d4d
Add `windows-legacy` opt-in backend
newpavlov Sep 19, 2025
67c2681
remove `getrandom_windows_legacy`
newpavlov Sep 19, 2025
caa81d5
rename windows7 to windows_legacy
newpavlov Sep 19, 2025
1b109d3
tweak build.rs
newpavlov Sep 19, 2025
e083a09
fix build.rs
newpavlov Sep 19, 2025
7277293
Update changelog
newpavlov Sep 19, 2025
2040acd
Add `compile_error!`
newpavlov Sep 19, 2025
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14 changes: 11 additions & 3 deletions CHANGELOG.md
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Expand Up @@ -6,18 +6,26 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0

## [0.3.4] - UNRELEASED

### Changed
- Relax MSRV for the `linux_raw` opt-in backend on ARM targets [#688]

### Added
- `unsupported` opt-in backend [#667]
- `windows_legacy` opt-in backend [#724]

### Changed
- Implement Memory Sanitizer unpoisoning more precisely [#678]
- Relax MSRV for the `linux_raw` opt-in backend on ARM targets [#688]
- Use `getrandom` syscall on all RISC-V Linux targets [#699]
- Replaced `wasi` dependency with `wasip2` [#721]

### Removed
- Unstable `rustc-dep-of-std` crate feature [#694]

[#667]: https://github.com/rust-random/getrandom/pull/667
[#678]: https://github.com/rust-random/getrandom/pull/678
[#688]: https://github.com/rust-random/getrandom/pull/688
[#694]: https://github.com/rust-random/getrandom/pull/694
[#699]: https://github.com/rust-random/getrandom/pull/699
[#721]: https://github.com/rust-random/getrandom/pull/721
[#724]: https://github.com/rust-random/getrandom/pull/724

## [0.3.3] - 2025-05-09

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48 changes: 24 additions & 24 deletions Cargo.lock
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3 changes: 1 addition & 2 deletions Cargo.toml
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Expand Up @@ -77,9 +77,8 @@ wasm-bindgen-test = "0.3"
[lints.rust.unexpected_cfgs]
level = "warn"
check-cfg = [
'cfg(getrandom_backend, values("custom", "efi_rng", "rdrand", "rndr", "linux_getrandom", "linux_raw", "wasm_js", "unsupported"))',
'cfg(getrandom_backend, values("custom", "efi_rng", "rdrand", "rndr", "linux_getrandom", "linux_raw", "wasm_js", "windows_legacy", "unsupported"))',
'cfg(getrandom_msan)',
'cfg(getrandom_windows_legacy)',
'cfg(getrandom_test_linux_fallback)',
'cfg(getrandom_test_linux_without_fallback)',
'cfg(getrandom_test_netbsd_fallback)',
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1 change: 1 addition & 0 deletions README.md
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Expand Up @@ -86,6 +86,7 @@ of randomness based on their specific needs:
| `rndr` | AArch64 | `aarch64-*` | [`RNDR`] register
| `wasm_js` | Web Browser, Node.js | `wasm32‑unknown‑unknown`, `wasm32v1-none` | [`Crypto.getRandomValues`]. Requires feature `wasm_js` ([see below](#webassembly-support)).
| `efi_rng` | UEFI | `*-unknown‑uefi` | [`EFI_RNG_PROTOCOL`] with `EFI_RNG_ALGORITHM_RAW` (requires `std` and Nightly compiler)
| `windows_legacy` | Windows | `*-windows-*` | [`RtlGenRandom`]
| `custom` | All targets | `*` | User-provided custom implementation (see [custom backend])
| `unsupported` | All targets | `*` | Always returns `Err(Error::UNSUPPORTED)` (see [unsupported backend])

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2 changes: 1 addition & 1 deletion build.rs
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Expand Up @@ -48,7 +48,7 @@ fn main() {

match rustc_minor_version() {
Some(minor_ver) if minor_ver < WIN7_INTRODUCED_MINOR_VER => {
println!("cargo:rustc-cfg=getrandom_windows_legacy");
println!("cargo:rustc-cfg=getrandom_backend=\"windows_legacy\"");
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@josephlr josephlr Sep 29, 2025

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One thing that concerned me about this line is if it would override users who used --getrandom_backend="whatever" on Windows when using an older compiler.

Turns out, I can be an issue, but depends on the value of "whatever". Opened #728 to fix.

}
None => println!("cargo:warning=Couldn't detect minor version of the Rust compiler"),
_ => {}
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9 changes: 6 additions & 3 deletions src/backends.rs
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Expand Up @@ -28,6 +28,9 @@ cfg_if! {
} else if #[cfg(getrandom_backend = "efi_rng")] {
mod efi_rng;
pub use efi_rng::*;
} else if #[cfg(getrandom_backend = "windows_legacy")] {
mod windows_legacy;
pub use windows_legacy::*;
} else if #[cfg(all(getrandom_backend = "wasm_js"))] {
cfg_if! {
if #[cfg(feature = "wasm_js")] {
Expand Down Expand Up @@ -173,9 +176,9 @@ cfg_if! {
} else if #[cfg(target_os = "solid_asp3")] {
mod solid;
pub use solid::*;
} else if #[cfg(all(windows, any(target_vendor = "win7", getrandom_windows_legacy)))] {
mod windows7;
pub use windows7::*;
} else if #[cfg(all(windows, target_vendor = "win7"))] {
mod windows_legacy;
pub use windows_legacy::*;
} else if #[cfg(windows)] {
mod windows;
pub use windows::*;
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3 changes: 3 additions & 0 deletions src/backends/windows7.rs → src/backends/windows_legacy.rs
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Expand Up @@ -14,6 +14,9 @@ use core::{ffi::c_void, mem::MaybeUninit};

pub use crate::util::{inner_u32, inner_u64};

#[cfg(not(windows))]
compile_error!("`windows_legacy` backend can be enabled only for Windows targets!");

// Binding to the Windows.Win32.Security.Authentication.Identity.RtlGenRandom
// API. Don't use windows-targets as it doesn't support Windows 7 targets.
#[link(name = "advapi32")]
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