Use /dev/urandom instead of getrandom() am: 7e6b92bc9c am: 36d78ff4a4 am: 13bc4fb605android-12.1.0_r9android-12.1.0_r8android-12.1.0_r7android-12.1.0_r22android-12.1.0_r21android-12.1.0_r20android-12.1.0_r19android-12.1.0_r11android-12.1.0_r10android-12.0.0_r32android-12.0.0_r29android-12.0.0_r28android-12.0.0_r27android-12.0.0_r26android-12.0.0_r21android-12.0.0_r20android-12.0.0_r19android-12.0.0_r18android-12.0.0_r16android12L-devandroid12-qpr3-s7-releaseandroid12-qpr3-s6-releaseandroid12-qpr3-s5-releaseandroid12-qpr3-s4-releaseandroid12-qpr3-s3-releaseandroid12-qpr3-s2-releaseandroid12-qpr3-s1-releaseandroid12-qpr3-releaseandroid12-qpr1-releaseandroid12-qpr1-d-s3-releaseandroid12-qpr1-d-s2-releaseandroid12-qpr1-d-s1-releaseandroid12-qpr1-d-releaseandroid12-dev

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/ahash/+/1683025

Change-Id: I0a1cb7e1a2e1ee9dd22c575fd6862a135eaa874d

2 files changed, 61 insertions, 1 deletions

diff --git a/patches/0001-Use-dev-urandom-instead-of-getrandom.patch b/patches/0001-Use-dev-urandom-instead-of-getrandom.patch
new file mode 100644
index 0000000..d5adff0
--- /dev/null
+++ b/patches/0001-Use-dev-urandom-instead-of-getrandom.patch
@@ -0,0 +1,49 @@
+From 5bce943cdb8fc81525257413f174844d644d63c8 Mon Sep 17 00:00:00 2001
+From: Eric Biggers <ebiggers@google.com>
+Date: Tue, 20 Apr 2021 16:48:07 -0700
+Subject: [PATCH] Use /dev/urandom instead of getrandom()
+
+To generate the ahash crate's default hash keys, use /dev/urandom
+instead of getrandom() to avoid blocking boot on systems where the
+entropy pool isn't initialized in time and where the use case of this
+crate doesn't actually require cryptographic randomness.
+
+If opening or reading from /dev/urandom fails, fall back to getrandom().
+
+Note that std::collections::HashMap doesn't block for randomness either,
+for the same reason.  So this change just makes ahash work like HashMap.
+
+Bug: 185934601
+Change-Id: Ie81a1f3a893d578348db11aee114d1a8f2d9fac5
+---
+diff --git a/src/random_state.rs b/src/random_state.rs
+index 501e3eb..9b3b3d0 100644
+--- a/src/random_state.rs
++++ b/src/random_state.rs
+@@ -10,11 +10,22 @@ use core::hash::Hasher;
+ use lazy_static::*;
+ use core::sync::atomic::{AtomicUsize, Ordering};
+ 
++#[cfg(all(feature = "runtime-rng", not(all(feature = "compile-time-rng", test))))]
++fn read_urandom(dest: &mut [u8]) -> Result<(), std::io::Error> {
++    use std::fs::File;
++    use std::io::Read;
++
++    let mut f = File::open("/dev/urandom")?;
++    f.read_exact(dest)
++}
++
+ #[cfg(all(feature = "runtime-rng", not(all(feature = "compile-time-rng", test))))]
+ lazy_static! {
+     static ref SEEDS: [[u64; 4]; 2] = {
+         let mut result: [u8; 64] = [0; 64];
+-        getrandom::getrandom(&mut result).expect("getrandom::getrandom() failed.");
++        if read_urandom(&mut result).is_err() {
++            getrandom::getrandom(&mut result).expect("getrandom::getrandom() failed.")
++        }
+         result.convert()
+     };
+ }
+-- 
+2.31.1.498.g6c1eba8ee3d-goog
+
diff --git a/src/random_state.rs b/src/random_state.rs
index 501e3eb..9b3b3d0 100644
--- a/src/random_state.rs
+++ b/src/random_state.rs
@@ -11,10 +11,21 @@ use lazy_static::*;
 use core::sync::atomic::{AtomicUsize, Ordering};
 
 #[cfg(all(feature = "runtime-rng", not(all(feature = "compile-time-rng", test))))]
+fn read_urandom(dest: &mut [u8]) -> Result<(), std::io::Error> {
+    use std::fs::File;
+    use std::io::Read;
+
+    let mut f = File::open("/dev/urandom")?;
+    f.read_exact(dest)
+}
+
+#[cfg(all(feature = "runtime-rng", not(all(feature = "compile-time-rng", test))))]
 lazy_static! {
     static ref SEEDS: [[u64; 4]; 2] = {
         let mut result: [u8; 64] = [0; 64];
-        getrandom::getrandom(&mut result).expect("getrandom::getrandom() failed.");
+        if read_urandom(&mut result).is_err() {
+            getrandom::getrandom(&mut result).expect("getrandom::getrandom() failed.")
+        }
         result.convert()
     };
 }