Add libevent

[netatalk.git] / libevent / evutil_rand.c

diff --git a/libevent/evutil_rand.c b/libevent/evutil_rand.c
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+++ b/libevent/evutil_rand.c
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+/*
+ * Copyright (c) 2007-2010 Niels Provos and Nick Mathewson
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* This file has our secure PRNG code.  On platforms that have arc4random(),
+ * we just use that.  Otherwise, we include arc4random.c as a bunch of static
+ * functions, and wrap it lightly.  We don't expose the arc4random*() APIs
+ * because A) they aren't in our namespace, and B) it's not nice to name your
+ * APIs after their implementations.  We keep them in a separate file
+ * so that other people can rip it out and use it for whatever.
+ */
+
+#include "event2/event-config.h"
+
+#include <limits.h>
+
+#include "util-internal.h"
+#include "evthread-internal.h"
+
+#ifdef _EVENT_HAVE_ARC4RANDOM
+#include <stdlib.h>
+#include <string.h>
+int
+evutil_secure_rng_init(void)
+{
+       /* call arc4random() now to force it to self-initialize */
+       (void) arc4random();
+       return 0;
+}
+
+#ifndef _EVENT_HAVE_ARC4RANDOM_BUF
+static void
+arc4random_buf(void *buf, size_t n)
+{
+       unsigned char *b = buf;
+       /* Make sure that we start out with b at a 4-byte alignment; plenty
+        * of CPUs care about this for 32-bit access. */
+       if (n >= 4 && ((ev_uintptr_t)b) & 3) {
+               ev_uint32_t u = arc4random();
+               int n_bytes = 4 - (((ev_uintptr_t)b) & 3);
+               memcpy(b, &u, n_bytes);
+               b += n_bytes;
+               n -= n_bytes;
+       }
+       while (n >= 4) {
+               *(ev_uint32_t*)b = arc4random();
+               b += 4;
+               n -= 4;
+       }
+       if (n) {
+               ev_uint32_t u = arc4random();
+               memcpy(b, &u, n);
+       }
+}
+#endif
+
+#else /* !_EVENT_HAVE_ARC4RANDOM { */
+
+#ifdef _EVENT_ssize_t
+#define ssize_t _EVENT_SSIZE_t
+#endif
+#define ARC4RANDOM_EXPORT static
+#define _ARC4_LOCK() EVLOCK_LOCK(arc4rand_lock, 0)
+#define _ARC4_UNLOCK() EVLOCK_UNLOCK(arc4rand_lock, 0)
+static void *arc4rand_lock;
+
+#define ARC4RANDOM_UINT32 ev_uint32_t
+#define ARC4RANDOM_NOSTIR
+#define ARC4RANDOM_NORANDOM
+#define ARC4RANDOM_NOUNIFORM
+
+#include "./arc4random.c"
+
+int
+evutil_secure_rng_init(void)
+{
+       int val;
+       if (!arc4rand_lock) {
+               EVTHREAD_ALLOC_LOCK(arc4rand_lock, 0);
+       }
+
+       _ARC4_LOCK();
+       if (!arc4_seeded_ok)
+               arc4_stir();
+       val = arc4_seeded_ok ? 0 : -1;
+       _ARC4_UNLOCK();
+       return val;
+}
+
+#endif /* } !_EVENT_HAVE_ARC4RANDOM */
+
+void
+evutil_secure_rng_get_bytes(void *buf, size_t n)
+{
+       arc4random_buf(buf, n);
+}
+
+void
+evutil_secure_rng_add_bytes(const char *buf, size_t n)
+{
+       arc4random_addrandom((unsigned char*)buf,
+           n>(size_t)INT_MAX ? INT_MAX : (int)n);
+}
+