From 6c20c8ed2cb9ab69a1a57ccb2b9b79969a808321 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 17:38:56 +0200 Subject: Adding upstream version 5.2.15. Signed-off-by: Daniel Baumann --- lib/sh/random.c | 240 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 240 insertions(+) create mode 100644 lib/sh/random.c (limited to 'lib/sh/random.c') diff --git a/lib/sh/random.c b/lib/sh/random.c new file mode 100644 index 0000000..1eaa71a --- /dev/null +++ b/lib/sh/random.c @@ -0,0 +1,240 @@ +/* random.c -- Functions for managing 16-bit and 32-bit random numbers. */ + +/* Copyright (C) 2020 Free Software Foundation, Inc. + + This file is part of GNU Bash, the Bourne Again SHell. + + Bash is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + Bash is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with Bash. If not, see . +*/ + +#include "config.h" + +#include "bashtypes.h" + +#if defined (HAVE_SYS_RANDOM_H) +# include +#endif + +#if defined (HAVE_UNISTD_H) +# include +#endif +#include "filecntl.h" + +#include +#include "bashansi.h" + +#include "shell.h" + +extern time_t shell_start_time; + +extern int last_random_value; + +static u_bits32_t intrand32 PARAMS((u_bits32_t)); +static u_bits32_t genseed PARAMS((void)); + +static u_bits32_t brand32 PARAMS((void)); +static void sbrand32 PARAMS((u_bits32_t)); +static void perturb_rand32 PARAMS((void)); + +/* The random number seed. You can change this by setting RANDOM. */ +static u_bits32_t rseed = 1; + +/* Returns a 32-bit pseudo-random number. */ +static u_bits32_t +intrand32 (last) + u_bits32_t last; +{ + /* Minimal Standard generator 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. Filtered through FreeBSD. + + x(n+1) = 16807 * x(n) mod (m). + + We split up the calculations to avoid overflow. + + h = last / q; l = x - h * q; t = a * l - h * r + m = 2147483647, a = 16807, q = 127773, r = 2836 + + There are lots of other combinations of constants to use; look at + https://www.gnu.org/software/gsl/manual/html_node/Other-random-number-generators.html#Other-random-number-generators */ + + bits32_t h, l, t; + u_bits32_t ret; + + /* Can't seed with 0. */ + ret = (last == 0) ? 123459876 : last; + h = ret / 127773; + l = ret - (127773 * h); + t = 16807 * l - 2836 * h; + ret = (t < 0) ? t + 0x7fffffff : t; + + return (ret); +} + +static u_bits32_t +genseed () +{ + struct timeval tv; + u_bits32_t iv; + + gettimeofday (&tv, NULL); + iv = (u_bits32_t)seedrand; /* let the compiler truncate */ + iv = tv.tv_sec ^ tv.tv_usec ^ getpid () ^ getppid () ^ current_user.uid ^ iv; + return (iv); +} + +#define BASH_RAND_MAX 32767 /* 0x7fff - 16 bits */ + +/* Returns a pseudo-random number between 0 and 32767. */ +int +brand () +{ + unsigned int ret; + + rseed = intrand32 (rseed); + if (shell_compatibility_level > 50) + ret = (rseed >> 16) ^ (rseed & 65535); + else + ret = rseed; + return (ret & BASH_RAND_MAX); +} + +/* Set the random number generator seed to SEED. */ +void +sbrand (seed) + unsigned long seed; +{ + rseed = seed; + last_random_value = 0; +} + +void +seedrand () +{ + u_bits32_t iv; + + iv = genseed (); + sbrand (iv); +} + +static u_bits32_t rseed32 = 1073741823; +static int last_rand32; + +static int urandfd = -1; + +#define BASH_RAND32_MAX 0x7fffffff /* 32 bits */ + +/* Returns a 32-bit pseudo-random number between 0 and 4294967295. */ +static u_bits32_t +brand32 () +{ + u_bits32_t ret; + + rseed32 = intrand32 (rseed32); + return (rseed32 & BASH_RAND32_MAX); +} + +static void +sbrand32 (seed) + u_bits32_t seed; +{ + last_rand32 = rseed32 = seed; +} + +void +seedrand32 () +{ + u_bits32_t iv; + + iv = genseed (); + sbrand32 (iv); +} + +static void +perturb_rand32 () +{ + rseed32 ^= genseed (); +} + +/* Force another attempt to open /dev/urandom on the next call to get_urandom32 */ +void +urandom_close () +{ + if (urandfd >= 0) + close (urandfd); + urandfd = -1; +} + +#if !defined (HAVE_GETRANDOM) +/* Imperfect emulation of getrandom(2). */ +#ifndef GRND_NONBLOCK +# define GRND_NONBLOCK 1 +# define GRND_RANDOM 2 +#endif + +static ssize_t +getrandom (buf, len, flags) + void *buf; + size_t len; + unsigned int flags; +{ + int oflags; + ssize_t r; + static int urand_unavail = 0; + +#if HAVE_GETENTROPY + r = getentropy (buf, len); + return (r == 0) ? len : -1; +#endif + + if (urandfd == -1 && urand_unavail == 0) + { + oflags = O_RDONLY; + if (flags & GRND_NONBLOCK) + oflags |= O_NONBLOCK; + urandfd = open ("/dev/urandom", oflags, 0); + if (urandfd >= 0) + SET_CLOSE_ON_EXEC (urandfd); + else + { + urand_unavail = 1; + return -1; + } + } + if (urandfd >= 0 && (r = read (urandfd, buf, len)) == len) + return (r); + return -1; +} +#endif + +u_bits32_t +get_urandom32 () +{ + u_bits32_t ret; + + if (getrandom ((void *)&ret, sizeof (ret), GRND_NONBLOCK) == sizeof (ret)) + return (last_rand32 = ret); + +#if defined (HAVE_ARC4RANDOM) + ret = arc4random (); +#else + if (subshell_environment) + perturb_rand32 (); + do + ret = brand32 (); + while (ret == last_rand32); +#endif + return (last_rand32 = ret); +} -- cgit v1.2.3