From 61d71ceb5d45e6caeaf08a63efeba931a10b32f3 Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Tue, 25 Jun 2013 13:53:36 -0700 Subject: [PATCH] random: Make thread-safe. Signed-off-by: Ben Pfaff --- lib/random.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/lib/random.c b/lib/random.c index 45d428c6b..da29fd0cf 100644 --- a/lib/random.c +++ b/lib/random.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc. + * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -22,6 +22,8 @@ #include #include "entropy.h" +#include "hash.h" +#include "ovs-thread.h" #include "timeval.h" #include "util.h" @@ -37,21 +39,25 @@ * cryptographic-quality randomness. */ /* Current random state. */ -static uint32_t seed; +DEFINE_PER_THREAD_DATA(uint32_t, seed, 0); static uint32_t random_next(void); void random_init(void) { - while (!seed) { + uint32_t *seedp = seed_get(); + while (!*seedp) { struct timeval tv; uint32_t entropy; + pthread_t self; xgettimeofday(&tv); get_entropy_or_die(&entropy, 4); + self = pthread_self(); - seed = tv.tv_sec ^ tv.tv_usec ^ entropy; + *seedp = (tv.tv_sec ^ tv.tv_usec ^ entropy + ^ hash_bytes(&self, sizeof self, 0)); } } @@ -59,7 +65,7 @@ void random_set_seed(uint32_t seed_) { ovs_assert(seed_); - seed = seed_; + *seed_get() = seed_; } void @@ -120,9 +126,11 @@ random_range(int max) static uint32_t random_next(void) { - seed ^= seed << 13; - seed ^= seed >> 17; - seed ^= seed << 5; + uint32_t *seedp = seed_get_unsafe(); - return seed; + *seedp ^= *seedp << 13; + *seedp ^= *seedp >> 17; + *seedp ^= *seedp << 5; + + return *seedp; } -- 2.43.0