From a5d4024139231ca10b5347d17bbf702cfdf5fd5b Mon Sep 17 00:00:00 2001
From: Keith Randall <khr@golang.org>
Date: Tue, 12 Mar 2013 10:47:44 -0700
Subject: runtime: faster & safer hash function

Uses AES hardware instructions on 386/amd64 to implement
a fast hash function.  Incorporates a random key to
thwart hash collision DOS attacks.
Depends on CL#7548043 for new assembly instructions.

Update #3885
Helps some by making hashing faster.  Go time drops from
0.65s to 0.51s.

R=rsc, r, bradfitz, remyoudompheng, khr, dsymonds, minux.ma, elias.naur
CC=golang-dev
https://golang.org/cl/7543043
---
 src/pkg/runtime/thread_openbsd.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'src/pkg/runtime/thread_openbsd.c')

diff --git a/src/pkg/runtime/thread_openbsd.c b/src/pkg/runtime/thread_openbsd.c
index 700c481475..f2d17404fd 100644
--- a/src/pkg/runtime/thread_openbsd.c
+++ b/src/pkg/runtime/thread_openbsd.c
@@ -159,6 +159,22 @@ runtime·osinit(void)
 	runtime·ncpu = getncpu();
 }
 
+void
+runtime·get_random_data(byte **rnd, int32 *rnd_len)
+{
+	static byte urandom_data[HashRandomBytes];
+	int32 fd;
+	fd = runtime·open("/dev/urandom", 0 /* O_RDONLY */, 0);
+	if(runtime·read(fd, urandom_data, HashRandomBytes) == HashRandomBytes) {
+		*rnd = urandom_data;
+		*rnd_len = HashRandomBytes;
+	} else {
+		*rnd = nil;
+		*rnd_len = 0;
+	}
+	runtime·close(fd);
+}
+
 void
 runtime·goenvs(void)
 {
-- 
cgit v1.3