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random.c
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random.c
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/*
+----------------------------------------------------------------------+
| PHP Version 7 |
+----------------------------------------------------------------------+
| Copyright (c) 1997-2015 The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 3.01 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
| available through the world-wide-web at the following url: |
| http://www.php.net/license/3_01.txt |
| If you did not receive a copy of the PHP license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| license@php.net so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Authors: Sammy Kaye Powers <me@sammyk.me> |
+----------------------------------------------------------------------+
*/
/* $Id$ */
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <math.h>
#include "php.h"
#include "zend_exceptions.h"
#include "php_random.h"
#if PHP_WIN32
# include "win32/winutil.h"
#endif
#ifdef ZTS
int random_globals_id;
#else
php_random_globals random_globals;
#endif
static void random_globals_ctor(php_random_globals *random_globals_p)
{
random_globals_p->fd = -1;
}
static void random_globals_dtor(php_random_globals *random_globals_p)
{
if (random_globals_p->fd > 0) {
close(random_globals_p->fd);
random_globals_p->fd = -1;
}
}
/* {{{ */
PHP_MINIT_FUNCTION(random)
{
#ifdef ZTS
ts_allocate_id(&random_globals_id, sizeof(php_random_globals), (ts_allocate_ctor)random_globals_ctor, (ts_allocate_dtor)random_globals_dtor);
#else
random_globals_ctor(&random_globals);
#endif
return SUCCESS;
}
/* }}} */
/* {{{ */
PHP_MSHUTDOWN_FUNCTION(random)
{
#ifndef ZTS
random_globals_dtor(&random_globals);
#endif
return SUCCESS;
}
/* }}} */
/* {{{ */
static int php_random_bytes(void *bytes, size_t size)
{
#if PHP_WIN32
/* Defer to CryptGenRandom on Windows */
if (php_win32_get_random_bytes(bytes, size) == FAILURE) {
php_error_docref(NULL, E_WARNING, "Could not gather sufficient random data");
return FAILURE;
}
#elif HAVE_DECL_ARC4RANDOM_BUF
arc4random_buf(bytes, size);
#else
int fd = RANDOM_G(fd);
size_t read_bytes = 0;
if (fd < 0) {
#if HAVE_DEV_ARANDOM
fd = open("/dev/arandom", O_RDONLY);
#elif HAVE_DEV_URANDOM
fd = open("/dev/urandom", O_RDONLY);
#endif
if (fd < 0) {
php_error_docref(NULL, E_WARNING, "Cannot open source device");
return FAILURE;
}
RANDOM_G(fd) = fd;
}
while (read_bytes < size) {
ssize_t n = read(fd, bytes + read_bytes, size - read_bytes);
if (n < 0) {
break;
}
read_bytes += n;
}
if (read_bytes < size) {
php_error_docref(NULL, E_WARNING, "Could not gather sufficient random data");
return FAILURE;
}
#endif
return SUCCESS;
}
/* }}} */
/* {{{ proto string random_bytes(int length)
Return an arbitrary length of pseudo-random bytes as binary string */
PHP_FUNCTION(random_bytes)
{
zend_long size;
zend_string *bytes;
if (zend_parse_parameters(ZEND_NUM_ARGS(), "l", &size) == FAILURE) {
return;
}
if (size < 1) {
zend_throw_exception(NULL, "Length must be greater than 0", 0);
return;
}
bytes = zend_string_alloc(size, 0);
if (php_random_bytes(ZSTR_VAL(bytes), size) == FAILURE) {
zend_string_release(bytes);
RETURN_FALSE;
}
ZSTR_VAL(bytes)[size] = '\0';
RETURN_STR(bytes);
}
/* }}} */
/* {{{ proto int random_int(int min, int max)
Return an arbitrary pseudo-random integer */
PHP_FUNCTION(random_int)
{
zend_long min;
zend_long max;
zend_ulong umax;
zend_ulong result;
if (zend_parse_parameters(ZEND_NUM_ARGS(), "ll", &min, &max) == FAILURE) {
return;
}
if (min > max) {
zend_throw_exception(NULL, "Minimum value must be less than or equal to the maximum value", 0);
return;
}
if (min == max) {
RETURN_LONG(min);
}
umax = max - min;
if (php_random_bytes(&result, sizeof(result)) == FAILURE) {
RETURN_FALSE;
}
/* Special case where no modulus is required */
if (umax == ZEND_ULONG_MAX) {
RETURN_LONG((zend_long)result);
}
/* Increment the max so the range is inclusive of max */
umax++;
/* Powers of two are not biased */
if ((umax & (umax - 1)) != 0) {
/* Ceiling under which ZEND_LONG_MAX % max == 0 */
zend_ulong limit = ZEND_ULONG_MAX - (ZEND_ULONG_MAX % umax) - 1;
/* Discard numbers over the limit to avoid modulo bias */
while (result > limit) {
if (php_random_bytes(&result, sizeof(result)) == FAILURE) {
RETURN_FALSE;
}
}
}
RETURN_LONG((zend_long)((result % umax) + min));
}
/* }}} */
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* End:
* vim600: sw=4 ts=4 fdm=marker
* vim<600: sw=4 ts=4
*/