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authorTimothy Arceri <tarceri@itsqueeze.com>2017-03-22 10:48:57 +1100
committerTimothy Arceri <tarceri@itsqueeze.com>2017-03-23 08:16:29 +1100
commitdd00a3c923ba94986efba2289c1b0e22b7c12c97 (patch)
tree3932a5a252144042e5eb7ff8f80cecc833656a61 /src/util
parent53660c23662edb829e6bfd54bcdc0df4688ec62b (diff)
util/rand_xor: add function to seed rand
V2: pass the seed to the seed function so that we can isolate its uses. Stop leaking fd when urandom couldn't be read. Reviewed-by: Grazvydas Ignotas <notasas@gmail.com> Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Diffstat (limited to 'src/util')
-rw-r--r--src/util/rand_xor.c65
-rw-r--r--src/util/rand_xor.h4
2 files changed, 69 insertions, 0 deletions
diff --git a/src/util/rand_xor.c b/src/util/rand_xor.c
index 07b4c22ee15..de05fa64b3c 100644
--- a/src/util/rand_xor.c
+++ b/src/util/rand_xor.c
@@ -1,3 +1,34 @@
+/*
+ * Copyright 2017 Timothy Arceri
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+
+#if defined(__linux__)
+#include <sys/file.h>
+#include <unistd.h>
+#else
+#include <time.h>
+#endif
+
#include "rand_xor.h"
/* Super fast random number generator.
@@ -18,3 +49,37 @@ rand_xorshift128plus(uint64_t *seed)
return s[1] + s0;
}
+
+void
+s_rand_xorshift128plus(uint64_t *seed, bool randomised_seed)
+{
+ if (!randomised_seed)
+ goto fixed_seed;
+
+#if defined(__linux__)
+ int fd = open("/dev/urandom", O_RDONLY);
+ if (fd < 0)
+ goto fixed_seed;
+
+ size_t seed_size = sizeof(uint64_t) * 2;
+ if (read(fd, seed, seed_size) != seed_size) {
+ close(fd);
+ goto fixed_seed;
+ }
+
+ close(fd);
+ return;
+
+#else
+ seed[0] = 0x3bffb83978e24f88;
+ seed[1] = time(NULL);
+
+ return;
+#endif
+
+fixed_seed:
+
+ /* Fallback to a fixed seed */
+ seed[0] = 0x3bffb83978e24f88;
+ seed[1] = 0x9238d5d56c71cd35;
+}
diff --git a/src/util/rand_xor.h b/src/util/rand_xor.h
index d5144e98230..532d549bcda 100644
--- a/src/util/rand_xor.h
+++ b/src/util/rand_xor.h
@@ -26,8 +26,12 @@
#define RAND_XOR_H
#include <stdint.h>
+#include <stdbool.h>
uint64_t
rand_xorshift128plus(uint64_t *seed);
+void
+s_rand_xorshift128plus(uint64_t *seed, bool randomised_seed);
+
#endif /* RAND_XOR_H */