diff options
author | Timothy Arceri <tarceri@itsqueeze.com> | 2017-03-22 10:48:57 +1100 |
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committer | Timothy Arceri <tarceri@itsqueeze.com> | 2017-03-23 08:16:29 +1100 |
commit | dd00a3c923ba94986efba2289c1b0e22b7c12c97 (patch) | |
tree | 3932a5a252144042e5eb7ff8f80cecc833656a61 /src/util/rand_xor.c | |
parent | 53660c23662edb829e6bfd54bcdc0df4688ec62b (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/rand_xor.c')
-rw-r--r-- | src/util/rand_xor.c | 65 |
1 files changed, 65 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; +} |