Use libc::getrandom on DragonflyBSD (#411)

This also moves the "only use libc::getrandom" implementaiton to its
own file, allowing multiple OSes to use it, simplifying the
implementation.

Bumps libc to include rust-lang/libc@e79e95f

Also moves Dragonfly to using `__errno_location`, as that binding was
added here: DragonFlyBSD/DragonFlyBSD@60d3113
which predates the introduction of `getrandom` support.

Signed-off-by: Joe Richey <[email protected]>

Author: josephlr

Cargo.toml

@@ -18,7 +18,7 @@ compiler_builtins = { version = "0.1", optional = true }
 core = { version = "1.0", optional = true, package = "rustc-std-workspace-core" }
 
 [target.'cfg(unix)'.dependencies]
-libc = { version = "0.2.149", default-features = false }
+libc = { version = "0.2.154", default-features = false }
 
 [target.'cfg(target_os = "wasi")'.dependencies]
 wasi = { version = "0.11", default-features = false }

src/3ds.rs

@@ -1,6 +1,5 @@
-//! Implementation for GNU/Hurd
-use crate::util_libc::sys_fill_exact;
-use crate::Error;
+//! Implementation using libc::getrandom
+use crate::{util_libc::sys_fill_exact, Error};
 use core::mem::MaybeUninit;
 
 pub fn getrandom_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {

src/dragonfly.rs

@@ -11,7 +11,7 @@
 //! | FreeBSD           | `*‑freebsd`        | [`getrandom`][5] if available, otherwise [`kern.arandom`][6]
 //! | OpenBSD           | `*‑openbsd`        | [`getentropy`][7]
 //! | NetBSD            | `*‑netbsd`         | [`getrandom`][16] if available, otherwise [`kern.arandom`][8]
-//! | Dragonfly BSD     | `*‑dragonfly`      | [`getrandom`][9] if available, otherwise [`/dev/urandom`][10] (identical to `/dev/random`)
+//! | Dragonfly BSD     | `*‑dragonfly`      | [`getrandom`][9]
 //! | Solaris, illumos  | `*‑solaris`, `*‑illumos` | [`getrandom`][11] if available, otherwise [`/dev/random`][12]
 //! | Fuchsia OS        | `*‑fuchsia`        | [`cprng_draw`]
 //! | Redox             | `*‑redox`          | `/dev/urandom`
@@ -177,7 +177,6 @@
 //! [7]: https://man.openbsd.org/getentropy.2
 //! [8]: https://man.netbsd.org/sysctl.7
 //! [9]: https://leaf.dragonflybsd.org/cgi/web-man?command=getrandom
-//! [10]: https://leaf.dragonflybsd.org/cgi/web-man?command=random&section=4
 //! [11]: https://docs.oracle.com/cd/E88353_01/html/E37841/getrandom-2.html
 //! [12]: https://docs.oracle.com/cd/E86824_01/html/E54777/random-7d.html
 //! [13]: https://github.com/emscripten-core/emscripten/pull/12240
@@ -239,6 +238,15 @@ cfg_if! {
     if #[cfg(any(target_os = "haiku", target_os = "redox", target_os = "nto", target_os = "aix"))] {
         mod util_libc;
         #[path = "use_file.rs"] mod imp;
+    } else if #[cfg(any(
+        target_os = "dragonfly",
+        target_os = "hurd",
+        // Check for target_arch = "arm" to only include the 3DS. Does not
+        // include the Nintendo Switch (which is target_arch = "aarch64").
+        all(target_os = "horizon", target_arch = "arm"),
+    ))] {
+        mod util_libc;
+        #[path = "getrandom.rs"] mod imp;
     } else if #[cfg(all(
         not(feature = "linux_disable_fallback"),
         any(
@@ -293,10 +301,6 @@ cfg_if! {
     } else if #[cfg(any(target_os = "freebsd", target_os = "netbsd"))] {
         mod util_libc;
         #[path = "bsd_arandom.rs"] mod imp;
-    } else if #[cfg(target_os = "dragonfly")] {
-        mod util_libc;
-        mod use_file;
-        #[path = "dragonfly.rs"] mod imp;
     } else if #[cfg(target_os = "fuchsia")] {
         #[path = "fuchsia.rs"] mod imp;
     } else if #[cfg(any(target_os = "ios", target_os = "visionos", target_os = "watchos", target_os = "tvos"))] {
@@ -320,11 +324,6 @@ cfg_if! {
         #[path = "espidf.rs"] mod imp;
     } else if #[cfg(windows)] {
         #[path = "windows.rs"] mod imp;
-    } else if #[cfg(all(target_os = "horizon", target_arch = "arm"))] {
-        // We check for target_arch = "arm" because the Nintendo Switch also
-        // uses Horizon OS (it is aarch64).
-        mod util_libc;
-        #[path = "3ds.rs"] mod imp;
     } else if #[cfg(target_os = "vita")] {
         mod util_libc;
         #[path = "vita.rs"] mod imp;
@@ -342,9 +341,6 @@ cfg_if! {
                         any(target_arch = "wasm32", target_arch = "wasm64"),
                         target_os = "unknown"))] {
         #[path = "js.rs"] mod imp;
-    } else if #[cfg(target_os = "hurd")] {
-        mod util_libc;
-        #[path = "hurd.rs"] mod imp;
     } else if #[cfg(feature = "custom")] {
         use custom as imp;
     } else if #[cfg(all(any(target_arch = "wasm32", target_arch = "wasm64"),

src/hurd.rs src/getrandom.rs

@@ -11,7 +11,7 @@ use libc::c_void;
 cfg_if! {
     if #[cfg(any(target_os = "netbsd", target_os = "openbsd", target_os = "android"))] {
         use libc::__errno as errno_location;
-    } else if #[cfg(any(target_os = "linux", target_os = "emscripten", target_os = "hurd", target_os = "redox"))] {
+    } else if #[cfg(any(target_os = "linux", target_os = "emscripten", target_os = "hurd", target_os = "redox", target_os = "dragonfly"))] {
         use libc::__errno_location as errno_location;
     } else if #[cfg(any(target_os = "solaris", target_os = "illumos"))] {
         use libc::___errno as errno_location;
@@ -35,10 +35,6 @@ cfg_if! {
 cfg_if! {
     if #[cfg(target_os = "vxworks")] {
         use libc::errnoGet as get_errno;
-    } else if #[cfg(target_os = "dragonfly")] {
-        // Until rust-lang/rust#29594 is stable, we cannot get the errno value
-        // on DragonFlyBSD. So we just return an out-of-range errno.
-        unsafe fn get_errno() -> libc::c_int { -1 }
     } else {
         unsafe fn get_errno() -> libc::c_int { *errno_location() }
     }