mirror of
https://github.com/LadybirdBrowser/ladybird.git
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e6f907a155
Problem:
- Many constructors are defined as `{}` rather than using the ` =
default` compiler-provided constructor.
- Some types provide an implicit conversion operator from `nullptr_t`
instead of requiring the caller to default construct. This violates
the C++ Core Guidelines suggestion to declare single-argument
constructors explicit
(https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c46-by-default-declare-single-argument-constructors-explicit).
Solution:
- Change default constructors to use the compiler-provided default
constructor.
- Remove implicit conversion operators from `nullptr_t` and change
usage to enforce type consistency without conversion.
122 lines
3.7 KiB
C++
122 lines
3.7 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* Copyright (c) 2020, Peter Elliott <pelliott@ualberta.ca>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/Singleton.h>
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#include <Kernel/Arch/i386/CPU.h>
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#include <Kernel/Devices/RandomDevice.h>
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#include <Kernel/Random.h>
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#include <Kernel/Time/TimeManagement.h>
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namespace Kernel {
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static AK::Singleton<KernelRng> s_the;
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KernelRng& KernelRng::the()
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{
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return *s_the;
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}
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KernelRng::KernelRng()
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{
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bool supports_rdseed = Processor::current().has_feature(CPUFeature::RDSEED);
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bool supports_rdrand = Processor::current().has_feature(CPUFeature::RDRAND);
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if (supports_rdseed || supports_rdrand) {
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for (size_t i = 0; i < resource().pool_count * resource().reseed_threshold; ++i) {
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u32 value = 0;
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if (supports_rdseed) {
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asm volatile(
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"1:\n"
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"rdseed %0\n"
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"jnc 1b\n"
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: "=r"(value));
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} else {
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asm volatile(
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"1:\n"
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"rdrand %0\n"
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"jnc 1b\n"
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: "=r"(value));
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}
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this->resource().add_random_event(value, i % 32);
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}
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}
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}
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void KernelRng::wait_for_entropy()
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{
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if (!resource().is_ready()) {
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m_seed_queue.wait_on({}, "KernelRng");
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}
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}
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void KernelRng::wake_if_ready()
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{
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if (resource().is_ready()) {
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m_seed_queue.wake_all();
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}
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}
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size_t EntropySource::next_source { 0 };
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void get_good_random_bytes(u8* buffer, size_t buffer_size)
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{
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KernelRng::the().wait_for_entropy();
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// FIXME: What if interrupts are disabled because we're in an interrupt?
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if (are_interrupts_enabled()) {
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LOCKER(KernelRng::the().lock());
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KernelRng::the().resource().get_random_bytes(buffer, buffer_size);
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} else {
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KernelRng::the().resource().get_random_bytes(buffer, buffer_size);
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}
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}
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void get_fast_random_bytes(u8* buffer, size_t buffer_size)
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{
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if (KernelRng::the().resource().is_ready()) {
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return get_good_random_bytes(buffer, buffer_size);
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}
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static u32 next = 1;
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union {
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u8 bytes[4];
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u32 value;
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} u;
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size_t offset = 4;
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for (size_t i = 0; i < buffer_size; ++i) {
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if (offset >= 4) {
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next = next * 1103515245 + 12345;
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u.value = next;
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offset = 0;
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}
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buffer[i] = u.bytes[offset++];
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}
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}
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}
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