Check for RDRAND failure

rust-random · Jul 9, 2016 · d386b5d · d386b5d
1 parent 6ca4943
commit d386b5d
Showing 1 changed file with 20 additions and 2 deletions.
diff --git a/src/os.rs b/src/os.rs
@@ -436,13 +436,31 @@ mod imp {
  impl Rng for OsRng {
  fn next_u32(&mut self) -> u32 {
  let ret;
- unsafe{asm!("rdrand $0":"=r"(ret):::"volatile")};
+ let mut retry=10;
+ unsafe{asm!("
+1:
+ rdrand $0
+ jc 2f
+ dec $1
+ jnz 1b
+2:
+ ":"=r"(ret),"=r"(retry):"1"(retry)::"volatile")};
+ if retry==0 { panic!("RDRAND failure") }
  ret
  }
  #[cfg(target_arch="x86_64")]
  fn next_u64(&mut self) -> u64 {
  let ret;
- unsafe{asm!("rdrand $0":"=r"(ret):::"volatile")};
+ let mut retry=10;
+ unsafe{asm!("
+1:
+ rdrand $0
+ jc 2f
+ dec $1
+ jnz 1b
+2:
+ ":"=r"(ret),"=r"(retry):"1"(retry)::"volatile")};
+ if retry==0 { panic!("RDRAND failure") }
  ret
  }
  }