use_file: std::sync::Mutex, dropping all libpthread use.

.clippy.toml

@@ -1 +1 @@
-msrv = "1.57"
+msrv = "1.63"

.github/workflows/tests.yml

@@ -44,7 +44,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-22.04, windows-2022]
-        toolchain: [nightly, beta, stable, 1.57]
+        toolchain: [nightly, beta, stable, 1.63]
         # Only Test macOS on stable to reduce macOS CI jobs
         include:
           # x86_64-apple-darwin.
@@ -348,6 +348,8 @@ jobs:
         ]
         include:
           # Supported tier 3 targets with libstd support
+          - target: aarch64-unknown-nto-qnx710
+            features: ["std"]
           - target: x86_64-unknown-openbsd
             features: ["std"]
           - target: x86_64-unknown-dragonfly

Cargo.toml

@@ -2,7 +2,7 @@
 name = "getrandom"
 version = "0.2.15" # Also update html_root_url in lib.rs when bumping this
 edition = "2021"
-rust-version = "1.57" # Sync .clippy.toml, tests.yml, and README.md.
+rust-version = "1.63" # Sync .clippy.toml, tests.yml, and README.md.
 authors = ["The Rand Project Developers"]
 license = "MIT OR Apache-2.0"
 description = "A small cross-platform library for retrieving random data from system source"

README.md

@@ -52,7 +52,7 @@ crate features, WASM support and Custom RNGs see the
 
 ## Minimum Supported Rust Version
 
-This crate requires Rust 1.57.0 or later.
+This crate requires Rust 1.63.0 or later.
 
 ## Platform Support
 

src/error.rs

@@ -58,6 +58,8 @@ impl Error {
     pub const NODE_ES_MODULE: Error = internal_error(14);
     /// Calling Windows ProcessPrng failed.
     pub const WINDOWS_PROCESS_PRNG: Error = internal_error(15);
+    /// The mutex used when opening the random file was poisoned.
+    pub const UNEXPECTED_FILE_MUTEX_POISONED: Error = internal_error(16);
 
     /// Codes below this point represent OS Errors (i.e. positive i32 values).
     /// Codes at or above this point, but below [`Error::CUSTOM_START`] are
@@ -175,6 +177,7 @@ fn internal_desc(error: Error) -> Option<&'static str> {
         Error::NODE_RANDOM_FILL_SYNC => Some("Calling Node.js API crypto.randomFillSync failed"),
         Error::NODE_ES_MODULE => Some("Node.js ES modules are not directly supported, see https://docs.rs/getrandom#nodejs-es-module-support"),
         Error::WINDOWS_PROCESS_PRNG => Some("ProcessPrng: Windows system function failure"),
+        Error::UNEXPECTED_FILE_MUTEX_POISONED => Some("File: Initialization panicked, poisoning the mutex"),
         _ => None,
     }
 }

src/linux_android_with_fallback.rs

@@ -1,7 +1,7 @@
 //! Implementation for Linux / Android with `/dev/urandom` fallback
 use crate::{
     lazy::LazyBool,
-    util_libc::{getrandom_syscall, last_os_error, sys_fill_exact},
+    util_libc::{getrandom_syscall, last_os_error, open_readonly, sys_fill_exact},
     {use_file, Error},
 };
 use core::mem::MaybeUninit;
@@ -31,3 +31,65 @@ fn is_getrandom_available() -> bool {
         true
     }
 }
+
+// Polls /dev/random to make sure it is ok to read from /dev/urandom.
+//
+// Polling avoids draining the estimated entropy from /dev/random;
+// short-lived processes reading even a single byte from /dev/random could
+// be problematic if they are being executed faster than entropy is being
+// collected.
+//
+// OTOH, reading a byte instead of polling is more compatible with
+// sandboxes that disallow `poll()` but which allow reading /dev/random,
+// e.g. sandboxes that assume that `poll()` is for network I/O. This way,
+// fewer applications will have to insert pre-sandbox-initialization logic.
+// Often (blocking) file I/O is not allowed in such early phases of an
+// application for performance and/or security reasons.
+//
+// It is hard to write a sandbox policy to support `libc::poll()` because
+// it may invoke the `poll`, `ppoll`, `ppoll_time64` (since Linux 5.1, with
+// newer versions of glibc), and/or (rarely, and probably only on ancient
+// systems) `select`. depending on the libc implementation (e.g. glibc vs
+// musl), libc version, potentially the kernel version at runtime, and/or
+// the target architecture.
+//
+// BoringSSL and libstd don't try to protect against insecure output from
+// `/dev/urandom'; they don't open `/dev/random` at all.
+//
+// OpenSSL uses `libc::select()` unless the `dev/random` file descriptor
+// is too large; if it is too large then it does what we do here.
+//
+// libsodium uses `libc::poll` similarly to this.
+pub fn wait_until_rng_ready() -> Result<(), Error> {
+    let fd = open_readonly(b"/dev/random\0")?;
+    let mut pfd = libc::pollfd {
+        fd,
+        events: libc::POLLIN,
+        revents: 0,
+    };
+    let _guard = DropGuard(|| unsafe {
+        libc::close(fd);
+    });
+
+    loop {
+        // A negative timeout means an infinite timeout.
+        let res = unsafe { libc::poll(&mut pfd, 1, -1) };
+        if res >= 0 {
+            debug_assert_eq!(res, 1); // We only used one fd, and cannot timeout.
+            return Ok(());
+        }
+        let err = crate::util_libc::last_os_error();
+        match err.raw_os_error() {
+            Some(libc::EINTR) | Some(libc::EAGAIN) => continue,
+            _ => return Err(err),
+        }
+    }
+}
+
+struct DropGuard<F: FnMut()>(F);
+
+impl<F: FnMut()> Drop for DropGuard<F> {
+    fn drop(&mut self) {
+        self.0()
+    }
+}

src/use_file.rs

@@ -4,11 +4,12 @@ use crate::{
     Error,
 };
 use core::{
-    cell::UnsafeCell,
     ffi::c_void,
     mem::MaybeUninit,
     sync::atomic::{AtomicUsize, Ordering::Relaxed},
 };
+extern crate std;
+use std::sync::{Mutex, PoisonError};
 
 /// For all platforms, we use `/dev/urandom` rather than `/dev/random`.
 /// For more information see the linked man pages in lib.rs.
@@ -44,19 +45,18 @@ fn get_rng_fd() -> Result<libc::c_int, Error> {
 
     #[cold]
     fn get_fd_locked() -> Result<libc::c_int, Error> {
-        // SAFETY: We use the mutex only in this method, and we always unlock it
-        // before returning, making sure we don't violate the pthread_mutex_t API.
-        static MUTEX: Mutex = Mutex::new();
-        unsafe { MUTEX.lock() };
-        let _guard = DropGuard(|| unsafe { MUTEX.unlock() });
+        static MUTEX: Mutex<()> = Mutex::new(());
+        let _guard = MUTEX
+            .lock()
+            .map_err(|_: PoisonError<_>| Error::UNEXPECTED_FILE_MUTEX_POISONED)?;
 
         if let Some(fd) = get_fd() {
             return Ok(fd);
         }
 
         // On Linux, /dev/urandom might return insecure values.
         #[cfg(any(target_os = "android", target_os = "linux"))]
-        wait_until_rng_ready()?;
+        crate::imp::wait_until_rng_ready()?;
 
         let fd = open_readonly(FILE_PATH)?;
         // The fd always fits in a usize without conflicting with FD_UNINIT.
@@ -73,84 +73,3 @@ fn get_rng_fd() -> Result<libc::c_int, Error> {
         get_fd_locked()
     }
 }
-
-// Polls /dev/random to make sure it is ok to read from /dev/urandom.
-//
-// Polling avoids draining the estimated entropy from /dev/random;
-// short-lived processes reading even a single byte from /dev/random could
-// be problematic if they are being executed faster than entropy is being
-// collected.
-//
-// OTOH, reading a byte instead of polling is more compatible with
-// sandboxes that disallow `poll()` but which allow reading /dev/random,
-// e.g. sandboxes that assume that `poll()` is for network I/O. This way,
-// fewer applications will have to insert pre-sandbox-initialization logic.
-// Often (blocking) file I/O is not allowed in such early phases of an
-// application for performance and/or security reasons.
-//
-// It is hard to write a sandbox policy to support `libc::poll()` because
-// it may invoke the `poll`, `ppoll`, `ppoll_time64` (since Linux 5.1, with
-// newer versions of glibc), and/or (rarely, and probably only on ancient
-// systems) `select`. depending on the libc implementation (e.g. glibc vs
-// musl), libc version, potentially the kernel version at runtime, and/or
-// the target architecture.
-//
-// BoringSSL and libstd don't try to protect against insecure output from
-// `/dev/urandom'; they don't open `/dev/random` at all.
-//
-// OpenSSL uses `libc::select()` unless the `dev/random` file descriptor
-// is too large; if it is too large then it does what we do here.
-//
-// libsodium uses `libc::poll` similarly to this.
-#[cfg(any(target_os = "android", target_os = "linux"))]
-fn wait_until_rng_ready() -> Result<(), Error> {
-    let fd = open_readonly(b"/dev/random\0")?;
-    let mut pfd = libc::pollfd {
-        fd,
-        events: libc::POLLIN,
-        revents: 0,
-    };
-    let _guard = DropGuard(|| unsafe {
-        libc::close(fd);
-    });
-
-    loop {
-        // A negative timeout means an infinite timeout.
-        let res = unsafe { libc::poll(&mut pfd, 1, -1) };
-        if res >= 0 {
-            debug_assert_eq!(res, 1); // We only used one fd, and cannot timeout.
-            return Ok(());
-        }
-        let err = crate::util_libc::last_os_error();
-        match err.raw_os_error() {
-            Some(libc::EINTR) | Some(libc::EAGAIN) => continue,
-            _ => return Err(err),
-        }
-    }
-}
-
-struct Mutex(UnsafeCell<libc::pthread_mutex_t>);
-
-impl Mutex {
-    const fn new() -> Self {
-        Self(UnsafeCell::new(libc::PTHREAD_MUTEX_INITIALIZER))
-    }
-    unsafe fn lock(&self) {
-        let r = libc::pthread_mutex_lock(self.0.get());
-        debug_assert_eq!(r, 0);
-    }
-    unsafe fn unlock(&self) {
-        let r = libc::pthread_mutex_unlock(self.0.get());
-        debug_assert_eq!(r, 0);
-    }
-}
-
-unsafe impl Sync for Mutex {}
-
-struct DropGuard<F: FnMut()>(F);
-
-impl<F: FnMut()> Drop for DropGuard<F> {
-    fn drop(&mut self) {
-        self.0()
-    }
-}