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Date:      Thu, 26 Jan 2012 21:50:21 +0400
From:      Andrey Chernov <ache@FreeBSD.ORG>
To:        John Baldwin <jhb@FreeBSD.ORG>, Mark Murray <markm@FreeBSD.ORG>, David Schultz <das@FreeBSD.ORG>, src-committers@FreeBSD.ORG, svn-src-all@FreeBSD.ORG, svn-src-head@FreeBSD.ORG
Subject:   Re: svn commit: r230230 - head/sys/dev/random
Message-ID:  <20120126175021.GA93016@vniz.net>
In-Reply-To: <20120126165521.GA92622@vniz.net>
References:  <E1Rny2A-000C3x-O6@groundzero.grondar.org> <20120126143819.GA88677@vniz.net> <20120126155626.GA92229@vniz.net> <201201261132.38320.jhb@freebsd.org> <20120126165521.GA92622@vniz.net>

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> On Thu, Jan 26, 2012 at 11:32:38AM -0500, John Baldwin wrote:
> > Atomics don't operate on enums.  You'll need to make it an int and just use 
> > #define's for the 3 states.

--- sys/libkern.h.old	2012-01-16 07:15:12.000000000 +0400
+++ sys/libkern.h	2012-01-26 21:40:21.000000000 +0400
@@ -72,6 +72,10 @@ static __inline quad_t qabs(quad_t a) { 
 
 /* Prototypes for non-quad routines. */
 struct malloc_type;
+#define	ARC4_ENTR_NONE	0	/* Don't have entropy yet. */
+#define	ARC4_ENTR_HAVE	1	/* Have entropy. */
+#define	ARC4_ENTR_SEED	2	/* Reseeding. */
+extern volatile int arc4rand_iniseed_state;
 uint32_t arc4random(void);
 void	 arc4rand(void *ptr, u_int len, int reseed);
 int	 bcmp(const void *, const void *, size_t);
--- dev/random/randomdev_soft.c.old	2011-03-02 01:42:19.000000000 +0300
+++ dev/random/randomdev_soft.c	2012-01-26 19:35:12.000000000 +0400
@@ -366,6 +366,8 @@ random_yarrow_unblock(void)
 		selwakeuppri(&random_systat.rsel, PUSER);
 		wakeup(&random_systat);
 	}
+	(void)atomic_cmpset_int(&arc4rand_iniseed_state,
+				ARC4_ENTR_NONE, ARC4_ENTR_HAVE);
 }
 
 static int
--- libkern/arc4random.c.old	2008-08-08 01:51:09.000000000 +0400
+++ libkern/arc4random.c	2012-01-26 21:40:47.000000000 +0400
@@ -24,6 +24,8 @@ __FBSDID("$FreeBSD: src/sys/libkern/arc4
 #define	ARC4_RESEED_SECONDS 300
 #define	ARC4_KEYBYTES (256 / 8)
 
+volatile int arc4rand_iniseed_state = ARC4_ENTR_NONE;
+
 static u_int8_t arc4_i, arc4_j;
 static int arc4_numruns = 0;
 static u_int8_t arc4_sbox[256];
@@ -130,7 +132,9 @@ arc4rand(void *ptr, u_int len, int resee
 	struct timeval tv;
 
 	getmicrouptime(&tv);
-	if (reseed || 
+	if (atomic_cmpset_int(&arc4rand_iniseed_state,
+			      ARC4_ENTR_HAVE, ARC4_ENTR_SEED) ||
+	   reseed ||
 	   (arc4_numruns > ARC4_RESEED_BYTES) ||
 	   (tv.tv_sec > arc4_t_reseed))
 		arc4_randomstir();

-- 
http://ache.vniz.net/



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