diff --git a/lib/libc/stdlib/rand.c b/lib/libc/stdlib/rand.c index 353f59349e1d..bddb0f040302 100644 --- a/lib/libc/stdlib/rand.c +++ b/lib/libc/stdlib/rand.c @@ -1,172 +1,167 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1990, 1993 * The Regents of the University of California. All rights reserved. * * 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. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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. * * Posix rand_r function added May 1999 by Wes Peters . */ #if defined(LIBC_SCCS) && !defined(lint) static char sccsid[] = "@(#)rand.c 8.1 (Berkeley) 6/14/93"; #endif /* LIBC_SCCS and not lint */ #include __FBSDID("$FreeBSD$"); #include "namespace.h" #include #include #include #include #include #include -#include #include "un-namespace.h" #include "random.h" /* * Implement rand(3), the standard C PRNG API, using the non-standard but * higher quality random(3) implementation and the same size 128-byte state * LFSR as the random(3) default. * * It turns out there are portable applications that want a PRNG but are too * lazy to use better-but-nonstandard interfaces like random(3), when * available, and too lazy to import higher-quality and faster PRNGs into their * codebase (such as any of SFC, JSF, 128-bit LCGs, PCG, or Splitmix64). * * Since we're stuck with rand(3) due to the C standard, we can at least have * it produce a relatively good PRNG sequence using our existing random(3) * LFSR. The random(3) design is not particularly fast nor compact, but it has * the advantage of being the one already in the tree. */ static struct __random_state *rand3_state; static void initialize_rand3(void) { - struct __random_state *state; int error; - state = allocatestate(TYPE_3); - error = initstate_r(state, 1, state->rst_randtbl, BREAK_3); + rand3_state = allocatestate(TYPE_3); + error = initstate_r(rand3_state, 1, rand3_state->rst_randtbl, BREAK_3); assert(error == 0); - if (!atomic_cmpset_rel_ptr((volatile uintptr_t *)&rand3_state, - (uintptr_t)NULL, (uintptr_t)state)) - free(state); } int rand(void) { if (rand3_state == NULL) initialize_rand3(); return ((int)random_r(rand3_state)); } void srand(unsigned seed) { if (rand3_state == NULL) initialize_rand3(); srandom_r(rand3_state, seed); } /* * FreeBSD 12 and prior compatibility implementation of rand(3). */ static int do_rand(unsigned long *ctx) { /* * Compute x = (7^5 * x) mod (2^31 - 1) * without overflowing 31 bits: * (2^31 - 1) = 127773 * (7^5) + 2836 * From "Random number generators: good ones are hard to find", * Park and Miller, Communications of the ACM, vol. 31, no. 10, * October 1988, p. 1195. */ long hi, lo, x; /* Transform to [1, 0x7ffffffe] range. */ x = (*ctx % 0x7ffffffe) + 1; hi = x / 127773; lo = x % 127773; x = 16807 * lo - 2836 * hi; if (x < 0) x += 0x7fffffff; /* Transform to [0, 0x7ffffffd] range. */ x--; *ctx = x; return (x); } /* * Can't fix this garbage; too little state. */ int rand_r(unsigned *ctx) { u_long val; int r; val = *ctx; r = do_rand(&val); *ctx = (unsigned)val; return (r); } static u_long next = 1; int __rand_fbsd12(void); int __rand_fbsd12(void) { return (do_rand(&next)); } __sym_compat(rand, __rand_fbsd12, FBSD_1.0); void __srand_fbsd12(unsigned seed); void __srand_fbsd12(unsigned seed) { next = seed; } __sym_compat(srand, __srand_fbsd12, FBSD_1.0); void __sranddev_fbsd12(void); void __sranddev_fbsd12(void) { static bool warned = false; if (!warned) { syslog(LOG_DEBUG, "Deprecated function sranddev() called"); warned = true; } } __sym_compat(sranddev, __sranddev_fbsd12, FBSD_1.0);