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AK+Everywhere: Change AK::fill_with_random to accept a Bytes object

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Rather than the very C-like API we currently have, accepting a void* and
a length, let's take a Bytes object instead. In almost all existing
cases, the compiler figures out the length.
This commit is contained in:
Timothy Flynn 2023-04-02 13:08:43 -04:00 • committed by Andreas Kling
parent 5c045b6934
commit 15532df83d
20 changed files with 37 additions and 39 deletions
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23
AK/Random.h
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@ -7,6 +7,7 @@
#pragma once
#include <AK/Platform.h>
#include <AK/Span.h>
#include <AK/StdLibExtras.h>
#include <AK/Types.h>
#include <stdlib.h>
@ -21,36 +22,32 @@
namespace AK {
inline void fill_with_random([[maybe_unused]] void* buffer, [[maybe_unused]] size_t length)
inline void fill_with_random([[maybe_unused]] Bytes bytes)
{
#if defined(AK_OS_SERENITY) || defined(AK_OS_ANDROID)
arc4random_buf(buffer, length);
arc4random_buf(bytes.data(), bytes.size());
#elif defined(OSS_FUZZ)
#else
auto fill_with_random_fallback = [&]() {
char* char_buffer = static_cast<char*>(buffer);
for (size_t i = 0; i < length; i++)
char_buffer[i] = rand();
for (auto& byte : bytes)
byte = rand();
};
# if defined(__unix__) or defined(AK_OS_MACOS)
// The maximum permitted value for the getentropy length argument.
static constexpr size_t getentropy_length_limit = 256;
auto iterations = length / getentropy_length_limit;
auto remainder = length % getentropy_length_limit;
auto address = reinterpret_cast<FlatPtr>(buffer);
auto iterations = bytes.size() / getentropy_length_limit;
for (size_t i = 0; i < iterations; ++i) {
if (getentropy(reinterpret_cast<void*>(address), getentropy_length_limit) != 0) {
if (getentropy(bytes.data(), getentropy_length_limit) != 0) {
fill_with_random_fallback();
return;
}
address += getentropy_length_limit;
bytes = bytes.slice(getentropy_length_limit);
}
if (remainder == 0 || getentropy(reinterpret_cast<void*>(address), remainder) == 0)
if (bytes.is_empty() || getentropy(bytes.data(), bytes.size()) == 0)
return;
# endif
@ -62,7 +59,7 @@ template<typename T>
inline T get_random()
{
T t;
fill_with_random(&t, sizeof(T));
fill_with_random({ &t, sizeof(T) });
return t;
}