diff --git a/src/system/libroot/posix/stdlib/random.c b/src/system/libroot/posix/stdlib/random.c index 8dc6bfd8aa..db8eccc091 100644 --- a/src/system/libroot/posix/stdlib/random.c +++ b/src/system/libroot/posix/stdlib/random.c @@ -1,4 +1,6 @@ -/* +/*- + * SPDX-License-Identifier: BSD-3-Clause + * * Copyright (c) 1983, 1993 * The Regents of the University of California. All rights reserved. * @@ -10,11 +12,7 @@ * 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. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. Neither the name of the University nor the names of its contributors + * 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. * @@ -29,16 +27,15 @@ * 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. - * - * $FreeBSD: src/lib/libc/stdlib/random.c,v 1.13 2000/01/27 23:06:49 jasone Exp $ - * */ -#include +#include #include - -/* An improved random number generation package. In addition to the standard +/* + * random.c: + * + * An improved random number generation package. In addition to the standard * rand()/srand() like interface, this package also has a special state info * interface. The initstate() routine is called with a seed, an array of * bytes, and a count of how many bytes are being passed in; this array is @@ -51,10 +48,10 @@ * congruential generator. If the amount of state information is less than * 32 bytes, a simple linear congruential R.N.G. is used. * - * Internally, the state information is treated as an array of longs; the + * Internally, the state information is treated as an array of uint32_t's; the * zeroeth element of the array is the type of R.N.G. being used (small * integer); the remainder of the array is the state information for the - * R.N.G. Thus, 32 bytes of state information will give 7 longs worth of + * R.N.G. Thus, 32 bytes of state information will give 7 ints worth of * state information, which will allow a degree seven polynomial. (Note: * the zeroeth word of state information also has some other information * stored in it -- see setstate() for details). @@ -70,7 +67,7 @@ * period of the generator is approximately deg*(2**deg - 1); thus doubling * the amount of state information has a vast influence on the period of the * generator. Note: the deg*(2**deg - 1) is an approximation only good for - * large deg, when the period of the shift register is the dominant factor. + * large deg, when the period of the shift is the dominant factor. * With deg equal to seven, the period is actually much longer than the * 7*(2**7 - 1) predicted by this formula. * @@ -132,8 +129,10 @@ */ #define MAX_TYPES 5 /* max number of types above */ -static long degrees[MAX_TYPES] = { DEG_0, DEG_1, DEG_2, DEG_3, DEG_4 }; -static long seps [MAX_TYPES] = { SEP_0, SEP_1, SEP_2, SEP_3, SEP_4 }; +#define NSHUFF 50 /* to drop some "seed -> 1st value" linearity */ + +static const int degrees[MAX_TYPES] = { DEG_0, DEG_1, DEG_2, DEG_3, DEG_4 }; +static const int seps [MAX_TYPES] = { SEP_0, SEP_1, SEP_2, SEP_3, SEP_4 }; /* * Initially, everything is set up as if from: @@ -149,25 +148,14 @@ static long seps [MAX_TYPES] = { SEP_0, SEP_1, SEP_2, SEP_3, SEP_4 }; * MAX_TYPES * (rptr - state) + TYPE_3 == TYPE_3. */ -static long randtbl[DEG_3 + 1] = { +static uint32_t randtbl[DEG_3 + 1] = { TYPE_3, -#ifdef USE_WEAK_SEEDING -/* Historic implementation compatibility */ -/* The random sequences do not vary much with the seed */ - 0x9a319039, 0x32d9c024, 0x9b663182, 0x5da1f342, 0xde3b81e0, 0xdf0a6fb5, - 0xf103bc02, 0x48f340fb, 0x7449e56b, 0xbeb1dbb0, 0xab5c5918, 0x946554fd, - 0x8c2e680f, 0xeb3d799f, 0xb11ee0b7, 0x2d436b86, 0xda672e2a, 0x1588ca88, - 0xe369735d, 0x904f35f7, 0xd7158fd6, 0x6fa6f051, 0x616e6b96, 0xac94efdc, - 0x36413f93, 0xc622c298, 0xf5a42ab8, 0x8a88d77b, 0xf5ad9d0e, 0x8999220b, - 0x27fb47b9, -#else /* !USE_WEAK_SEEDING */ - 0x991539b1, 0x16a5bce3, 0x6774a4cd, 0x3e01511e, 0x4e508aaa, 0x61048c05, - 0xf5500617, 0x846b7115, 0x6a19892c, 0x896a97af, 0xdb48f936, 0x14898454, - 0x37ffd106, 0xb58bff9c, 0x59e17104, 0xcf918a49, 0x09378c83, 0x52c7a471, - 0x8d293ea9, 0x1f4fc301, 0xc3db71be, 0x39b44e1c, 0xf8a44ef9, 0x4c8b80b1, - 0x19edc328, 0x87bf4bdd, 0xc9b240e5, 0xe9ee4b1b, 0x4382aee7, 0x535b6b41, - 0xf3bec5da -#endif /* !USE_WEAK_SEEDING */ + 0x2cf41758, 0x27bb3711, 0x4916d4d1, 0x7b02f59f, 0x9b8e28eb, 0xc0e80269, + 0x696f5c16, 0x878f1ff5, 0x52d9c07f, 0x916a06cd, 0xb50b3a20, 0x2776970a, + 0xee4eb2a6, 0xe94640ec, 0xb1d65612, 0x9d1ed968, 0x1043f6b7, 0xa3432a76, + 0x17eacbb9, 0x3c09e2eb, 0x4f8c2b3, 0x708a1f57, 0xee341814, 0x95d0e4d2, + 0xb06f216c, 0x8bd2e72e, 0x8f7c38d7, 0xcfc6a8fc, 0x2a59495, 0xa20d2a69, + 0xe29d12d1 }; /* @@ -184,8 +172,8 @@ static long randtbl[DEG_3 + 1] = { * in the initialization of randtbl) because the state table pointer is set * to point to randtbl[1] (as explained below). */ -static long *fptr = &randtbl[SEP_3 + 1]; -static long *rptr = &randtbl[1]; +static uint32_t *fptr = &randtbl[SEP_3 + 1]; +static uint32_t *rptr = &randtbl[1]; /* * The following things are the pointer to the state information table, the @@ -197,24 +185,15 @@ static long *rptr = &randtbl[1]; * this is more efficient than indexing every time to find the address of * the last element to see if the front and rear pointers have wrapped. */ -static long *state = &randtbl[1]; -static long rand_type = TYPE_3; -static long rand_deg = DEG_3; -static long rand_sep = SEP_3; -static long *end_ptr = &randtbl[DEG_3 + 1]; +static uint32_t *state = &randtbl[1]; +static int rand_type = TYPE_3; +static int rand_deg = DEG_3; +static int rand_sep = SEP_3; +static uint32_t *end_ptr = &randtbl[DEG_3 + 1]; -static inline long good_rand(long); - -static inline long good_rand(long x) +static inline uint32_t +good_rand(uint32_t ctx) { -#ifdef USE_WEAK_SEEDING -/* - * Historic implementation compatibility. - * The random sequences do not vary much with the seed, - * even with overflowing. - */ - return (1103515245 * x + 12345); -#else /* !USE_WEAK_SEEDING */ /* * Compute x = (7^5 * x) mod (2^31 - 1) * wihout overflowing 31 bits: @@ -223,15 +202,17 @@ static inline long good_rand(long x) * Park and Miller, Communications of the ACM, vol. 31, no. 10, * October 1988, p. 1195. */ - register long hi, lo; + int32_t 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) + if (x < 0) x += 0x7fffffff; - return (x); -#endif /* !USE_WEAK_SEEDING */ + /* Transform to [0, 0x7ffffffd] range. */ + return (x - 1); } /* @@ -249,61 +230,56 @@ static inline long good_rand(long x) void srandom(unsigned int x) { - long i; + int i, lim; - if (rand_type == TYPE_0) { - state[0] = x; - } else { - state[0] = x; - for (i = 1; i < rand_deg; i++) { + state[0] = (uint32_t)x; + if (rand_type == TYPE_0) + lim = NSHUFF; + else { + for (i = 1; i < rand_deg; i++) state[i] = good_rand(state[i - 1]); - } fptr = &state[rand_sep]; rptr = &state[0]; - for (i = 0; i < 10 * rand_deg; i++) { - (void)random(); - } + lim = 10 * rand_deg; } + for (i = 0; i < lim; i++) + (void)random(); } /* * srandomdev: * * Many programs choose the seed value in a totally predictable manner. - * This often causes problems. We seed the generator using the much more - * secure urandom(4) interface. Note that this particular seeding - * procedure can generate states which are impossible to reproduce by - * calling srandom() with any value, since the succeeding terms in the - * state buffer are no longer derived from the LC algorithm applied to - * a fixed seed. + * This often causes problems. We seed the generator using pseudo-random + * data from the kernel. + * + * Note that this particular seeding procedure can generate states + * which are impossible to reproduce by calling srandom() with any + * value, since the succeeding terms in the state buffer are no longer + * derived from the LC algorithm applied to a fixed seed. */ #if 0 void -srandomdev() +srandomdev(void) { - int fd, done; - size_t len; + int mib[2]; + size_t expected, len; if (rand_type == TYPE_0) - len = sizeof state[0]; + expected = len = sizeof(state[0]); else - len = rand_deg * sizeof state[0]; + expected = len = rand_deg * sizeof(state[0]); - done = 0; - fd = _open("/dev/urandom", O_RDONLY, 0); - if (fd >= 0) { - if (_read(fd, (void *) state, len) == (ssize_t) len) - done = 1; - _close(fd); - } - - if (!done) { - struct timeval tv; - unsigned long junk; - - gettimeofday(&tv, NULL); - srandom(getpid() ^ tv.tv_sec ^ tv.tv_usec ^ junk); - return; + mib[0] = CTL_KERN; + mib[1] = KERN_ARND; + if (sysctl(mib, 2, state, &len, NULL, 0) == -1 || len != expected) { + /* + * The sysctl cannot fail. If it does fail on some FreeBSD + * derivative or after some future change, just abort so that + * the problem will be found and fixed. abort is not normally + * suitable for a library but makes sense here. + */ + abort(); } if (rand_type != TYPE_0) { @@ -332,25 +308,22 @@ srandomdev() * * Returns a pointer to the old state. * - * Note: The Sparc platform requires that arg_state begin on a long + * Note: The Sparc platform requires that arg_state begin on an int * word boundary; otherwise a bus error will occur. Even so, lint will * complain about mis-alignment, but you should disregard these messages. */ char * initstate(unsigned int seed, char *arg_state, size_t n) { - register char *ostate = (char *)(&state[-1]); - register long *long_arg_state = (long *) arg_state; + char *ostate = (char *)(&state[-1]); + uint32_t *int_arg_state = (uint32_t *)arg_state; + if (n < BREAK_0) + return (NULL); if (rand_type == TYPE_0) state[-1] = rand_type; else state[-1] = MAX_TYPES * (rptr - state) + rand_type; - if (n < BREAK_0) { - (void)fprintf(stderr, - "random: not enough state (%ld bytes); ignored.\n", n); - return(0); - } if (n < BREAK_1) { rand_type = TYPE_0; rand_deg = DEG_0; @@ -372,14 +345,14 @@ initstate(unsigned int seed, char *arg_state, size_t n) rand_deg = DEG_4; rand_sep = SEP_4; } - state = (long *) (long_arg_state + 1); /* first location */ + state = int_arg_state + 1; /* first location */ end_ptr = &state[rand_deg]; /* must set end_ptr before srandom */ srandom(seed); if (rand_type == TYPE_0) - long_arg_state[0] = rand_type; + int_arg_state[0] = rand_type; else - long_arg_state[0] = MAX_TYPES * (rptr - state) + rand_type; - return(ostate); + int_arg_state[0] = MAX_TYPES * (rptr - state) + rand_type; + return (ostate); } /* @@ -397,47 +370,36 @@ initstate(unsigned int seed, char *arg_state, size_t n) * * Returns a pointer to the old state information. * - * Note: The Sparc platform requires that arg_state begin on a long + * Note: The Sparc platform requires that arg_state begin on an int * word boundary; otherwise a bus error will occur. Even so, lint will * complain about mis-alignment, but you should disregard these messages. */ char * -setstate(arg_state) - char *arg_state; /* pointer to state array */ +setstate(char *arg_state) { - register long *new_state = (long *) arg_state; - register long type = new_state[0] % MAX_TYPES; - register long rear = new_state[0] / MAX_TYPES; + uint32_t *new_state = (uint32_t *)arg_state; + uint32_t type = new_state[0] % MAX_TYPES; + uint32_t rear = new_state[0] / MAX_TYPES; char *ostate = (char *)(&state[-1]); + if (type != TYPE_0 && rear >= degrees[type]) + return (NULL); if (rand_type == TYPE_0) state[-1] = rand_type; else state[-1] = MAX_TYPES * (rptr - state) + rand_type; - switch(type) { - case TYPE_0: - case TYPE_1: - case TYPE_2: - case TYPE_3: - case TYPE_4: - rand_type = type; - rand_deg = degrees[type]; - rand_sep = seps[type]; - break; - default: - (void)fprintf(stderr, - "random: state info corrupted; not changed.\n"); - } - state = (long *) (new_state + 1); + rand_type = type; + rand_deg = degrees[type]; + rand_sep = seps[type]; + state = new_state + 1; if (rand_type != TYPE_0) { rptr = &state[rear]; fptr = &state[(rear + rand_sep) % rand_deg]; } end_ptr = &state[rand_deg]; /* set end_ptr too */ - return(ostate); + return (ostate); } - /* * random: * @@ -458,20 +420,19 @@ setstate(arg_state) int random(void) { - long i; - long *f; - long *r; + uint32_t i; + uint32_t *f, *r; if (rand_type == TYPE_0) { i = state[0]; - state[0] = i = (good_rand(i)) & 0x7fffffff; + state[0] = i = good_rand(i); } else { /* * Use local variables rather than static variables for speed. */ f = fptr; r = rptr; *f += *r; - i = (*f >> 1) & 0x7fffffff; /* chucking least random bit */ + i = *f >> 1; /* chucking least random bit */ if (++f >= end_ptr) { f = state; ++r; @@ -482,5 +443,5 @@ random(void) fptr = f; rptr = r; } - return(i); + return ((long)i); }