mirror of
https://gitlab.com/gnuwget/wget2.git
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141 lines
3.1 KiB
C
141 lines
3.1 KiB
C
/*
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* Copyright (c) 2012 Tim Ruehsen
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* Copyright (c) 2016-2024 Free Software Foundation, Inc.
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*
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* This file is part of libwget.
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*
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* Libwget is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Libwget is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with libwget. If not, see <https://www.gnu.org/licenses/>.
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*
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*
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* a multi-thread safe wrapper around gnulib random_r()
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*
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* Changelog
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* 22.01.2016 Tim Ruehsen created
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*
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*/
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#include <config.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <time.h>
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#ifdef _WIN32
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# include <process.h> /* getpid() */
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#endif
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#include <wget.h>
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#include "private.h"
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/**
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* \file
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* \brief Random functions
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* \defgroup libwget-random Random functions
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* @{
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*
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* This is wrapper code around gnulib's srandom_r() and random_r() with automatic seeding
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*/
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static int seeded;
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static char statebuf[64];
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static struct random_data state;
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static wget_thread_mutex mutex;
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static bool initialized;
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static void random_exit(void)
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{
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if (initialized) {
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wget_thread_mutex_destroy(&mutex);
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initialized = false;
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}
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}
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INITIALIZER(random_init)
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{
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if (!initialized) {
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wget_thread_mutex_init(&mutex);
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initialized = true;
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atexit(random_exit);
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}
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}
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/**
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* Random API initialization, allocating/preparing the internal resources.
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*
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* On systems with automatic library constructors, this function
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* doesn't have to be called explicitly.
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*
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* This function is not thread-safe.
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*/
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void wget_random_init(void)
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{
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random_init();
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}
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/**
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* Random API deinitialization, free'ing all internal resources.
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*
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* On systems with automatic library destructors, this function
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* doesn't have to be called explicitly.
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*
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* This function is not thread-safe.
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*/
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void wget_random_exit(void)
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{
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random_exit();
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}
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/**
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* \return Random value between 0 and RAND_MAX
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*
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* This functions wraps around gnulib's random_r(). It performs a thread-safe seeding on the first use,
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* if not done before by wget_srandom();
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*/
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int wget_random(void)
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{
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int32_t r;
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wget_thread_mutex_lock(mutex);
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if (!seeded) {
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// seed random generator, used e.g. by Digest Authentication and --random-wait
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initstate_r((unsigned)(time(NULL) ^ getpid()), statebuf, sizeof(statebuf), &state);
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seeded = 1;
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}
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if (random_r(&state, &r))
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r = 0; // return 0 on failure
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wget_thread_mutex_unlock(mutex);
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return (int)r;
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}
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/**
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* \param[in] seed Value to seed the random generator
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*
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* This functions wraps around srandom_r() to make a thread-safe seeding for wget_random().
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*/
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void wget_srandom(unsigned int seed)
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{
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wget_thread_mutex_lock(mutex);
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initstate_r(seed, statebuf, sizeof(statebuf), &state);
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seeded = 1;
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wget_thread_mutex_unlock(mutex);
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}
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/**@}*/
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