/* (c) Magnus Auvinen. See licence.txt in the root of the distribution for more information. */
/* If you are missing that file, acquire a complete release at teeworlds.com.                */
#include "system.h"

#include "lock.h"
#include "logger.h"
#include "windows.h"

#include <sys/types.h>

#include <atomic>
#include <cctype>
#include <charconv>
#include <chrono>
#include <cinttypes>
#include <cmath>
#include <cstdarg>
#include <cstdio>
#include <cstring>
#include <iterator> // std::size
#include <mutex>
#include <string_view>

#if defined(CONF_WEBSOCKETS)
#include <engine/shared/websockets.h>
#endif

#if defined(CONF_FAMILY_UNIX)
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/utsname.h>
#include <sys/wait.h>
#include <unistd.h>

#include <csignal>
#include <locale>

/* unix net includes */
#include <arpa/inet.h>
#include <dirent.h>
#include <netdb.h>
#include <netinet/in.h>
#include <pthread.h>
#include <sys/ioctl.h>
#include <sys/socket.h>

#include <cerrno>

#if defined(CONF_PLATFORM_MACOS)
// some lock and pthread functions are already defined in headers
// included from Carbon.h
// this prevents having duplicate definitions of those
#define _lock_set_user_
#define _task_user_

#include <Carbon/Carbon.h>
#include <CoreFoundation/CoreFoundation.h>
#include <mach-o/dyld.h>
#include <mach/mach_time.h>

#if defined(__MAC_10_10) && __MAC_OS_X_VERSION_MIN_REQUIRED >= __MAC_10_10
#include <pthread/qos.h>
#endif
#endif

#elif defined(CONF_FAMILY_WINDOWS)
#include <io.h>
#include <objbase.h>
#include <process.h>
#include <shellapi.h>
#include <shlobj.h> // SHGetKnownFolderPath
#include <shlwapi.h>
#include <wincrypt.h>
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>

#include <cerrno>
#include <cfenv>
#else
#error NOT IMPLEMENTED
#endif

#if defined(CONF_PLATFORM_SOLARIS)
#include <sys/filio.h>
#endif

#if defined(CONF_PLATFORM_EMSCRIPTEN)
#include <emscripten/emscripten.h>
#endif

static NETSTATS network_stats = {0};

#define VLEN 128
#define PACKETSIZE 1400
typedef struct
{
#ifdef CONF_PLATFORM_LINUX
	int pos;
	int size;
	struct mmsghdr msgs[VLEN];
	struct iovec iovecs[VLEN];
	char bufs[VLEN][PACKETSIZE];
	char sockaddrs[VLEN][128];
#else
	char buf[PACKETSIZE];
#endif
} NETSOCKET_BUFFER;

void net_buffer_init(NETSOCKET_BUFFER *buffer);
void net_buffer_reinit(NETSOCKET_BUFFER *buffer);
void net_buffer_simple(NETSOCKET_BUFFER *buffer, char **buf, int *size);

struct NETSOCKET_INTERNAL
{
	int type;
	int ipv4sock;
	int ipv6sock;
	int web_ipv4sock;
	int web_ipv6sock;

	NETSOCKET_BUFFER buffer;
};
static NETSOCKET_INTERNAL invalid_socket = {NETTYPE_INVALID, -1, -1, -1, -1};

IOHANDLE io_open(const char *filename, int flags)
{
	dbg_assert(flags == IOFLAG_READ || flags == IOFLAG_WRITE || flags == IOFLAG_APPEND, "flags must be read, write or append");
#if defined(CONF_FAMILY_WINDOWS)
	const std::wstring wide_filename = windows_utf8_to_wide(filename);
	DWORD desired_access;
	DWORD creation_disposition;
	const char *open_mode;
	if((flags & IOFLAG_READ) != 0)
	{
		desired_access = FILE_READ_DATA;
		creation_disposition = OPEN_EXISTING;
		open_mode = "rb";
	}
	else if(flags == IOFLAG_WRITE)
	{
		desired_access = FILE_WRITE_DATA;
		creation_disposition = CREATE_ALWAYS;
		open_mode = "wb";
	}
	else if(flags == IOFLAG_APPEND)
	{
		desired_access = FILE_APPEND_DATA;
		creation_disposition = OPEN_ALWAYS;
		open_mode = "ab";
	}
	else
	{
		dbg_assert_failed("logic error");
	}
	HANDLE handle = CreateFileW(wide_filename.c_str(), desired_access, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, nullptr, creation_disposition, FILE_ATTRIBUTE_NORMAL, nullptr);
	if(handle == INVALID_HANDLE_VALUE)
		return nullptr;
	const int file_descriptor = _open_osfhandle((intptr_t)handle, 0);
	dbg_assert(file_descriptor != -1, "_open_osfhandle failure");
	FILE *file_stream = _fdopen(file_descriptor, open_mode);
	dbg_assert(file_stream != nullptr, "_fdopen failure");
	return file_stream;
#else
	const char *open_mode;
	if((flags & IOFLAG_READ) != 0)
	{
		open_mode = "rb";
	}
	else if(flags == IOFLAG_WRITE)
	{
		open_mode = "wb";
	}
	else if(flags == IOFLAG_APPEND)
	{
		open_mode = "ab";
	}
	else
	{
		dbg_assert_failed("Invalid flags: %d", flags);
	}
	return fopen(filename, open_mode);
#endif
}

unsigned io_read(IOHANDLE io, void *buffer, unsigned size)
{
	return fread(buffer, 1, size, (FILE *)io);
}

bool io_read_all(IOHANDLE io, void **result, unsigned *result_len)
{
	// Loading files larger than 1 GiB into memory is not supported.
	constexpr int64_t MAX_FILE_SIZE = (int64_t)1024 * 1024 * 1024;

	int64_t real_len = io_length(io);
	if(real_len > MAX_FILE_SIZE)
	{
		*result = nullptr;
		*result_len = 0;
		return false;
	}

	int64_t len = real_len < 0 ? 1024 : real_len; // use default initial size if we couldn't get the length
	char *buffer = (char *)malloc(len + 1);
	int64_t read = io_read(io, buffer, len + 1); // +1 to check if the file size is larger than expected
	if(read < len)
	{
		buffer = (char *)realloc(buffer, read + 1);
		len = read;
	}
	else if(read > len)
	{
		int64_t cap = 2 * read;
		if(cap > MAX_FILE_SIZE)
		{
			free(buffer);
			*result = nullptr;
			*result_len = 0;
			return false;
		}
		len = read;
		buffer = (char *)realloc(buffer, cap);
		while((read = io_read(io, buffer + len, cap - len)) != 0)
		{
			len += read;
			if(len == cap)
			{
				cap *= 2;
				if(cap > MAX_FILE_SIZE)
				{
					free(buffer);
					*result = nullptr;
					*result_len = 0;
					return false;
				}
				buffer = (char *)realloc(buffer, cap);
			}
		}
		buffer = (char *)realloc(buffer, len + 1);
	}
	buffer[len] = 0;
	*result = buffer;
	*result_len = len;
	return true;
}

char *io_read_all_str(IOHANDLE io)
{
	void *buffer;
	unsigned len;
	if(!io_read_all(io, &buffer, &len))
	{
		return nullptr;
	}
	if(mem_has_null(buffer, len))
	{
		free(buffer);
		return nullptr;
	}
	return (char *)buffer;
}

int io_skip(IOHANDLE io, int64_t size)
{
	return io_seek(io, size, IOSEEK_CUR);
}

int io_seek(IOHANDLE io, int64_t offset, ESeekOrigin origin)
{
	int real_origin;
	switch(origin)
	{
	case IOSEEK_START:
		real_origin = SEEK_SET;
		break;
	case IOSEEK_CUR:
		real_origin = SEEK_CUR;
		break;
	case IOSEEK_END:
		real_origin = SEEK_END;
		break;
	default:
		dbg_assert_failed("Invalid origin: %d", origin);
	}
#if defined(CONF_FAMILY_WINDOWS)
	return _fseeki64((FILE *)io, offset, real_origin);
#else
	return fseeko((FILE *)io, offset, real_origin);
#endif
}

int64_t io_tell(IOHANDLE io)
{
#if defined(CONF_FAMILY_WINDOWS)
	return _ftelli64((FILE *)io);
#else
	return ftello((FILE *)io);
#endif
}

int64_t io_length(IOHANDLE io)
{
	if(io_seek(io, 0, IOSEEK_END) != 0)
	{
		return -1;
	}
	const int64_t length = io_tell(io);
	if(io_seek(io, 0, IOSEEK_START) != 0)
	{
		return -1;
	}
	return length;
}

unsigned io_write(IOHANDLE io, const void *buffer, unsigned size)
{
	return fwrite(buffer, 1, size, (FILE *)io);
}

bool io_write_newline(IOHANDLE io)
{
#if defined(CONF_FAMILY_WINDOWS)
	return io_write(io, "\r\n", 2) == 2;
#else
	return io_write(io, "\n", 1) == 1;
#endif
}

int io_close(IOHANDLE io)
{
	return fclose((FILE *)io) != 0;
}

int io_flush(IOHANDLE io)
{
	return fflush((FILE *)io);
}

int io_sync(IOHANDLE io)
{
	if(io_flush(io))
	{
		return 1;
	}
#if defined(CONF_FAMILY_WINDOWS)
	return FlushFileBuffers((HANDLE)_get_osfhandle(_fileno((FILE *)io))) == FALSE;
#else
	return fsync(fileno((FILE *)io)) != 0;
#endif
}

int io_error(IOHANDLE io)
{
	return ferror((FILE *)io);
}

IOHANDLE io_stdin()
{
	return stdin;
}

IOHANDLE io_stdout()
{
	return stdout;
}

IOHANDLE io_stderr()
{
	return stderr;
}

IOHANDLE io_current_exe()
{
	// From https://stackoverflow.com/a/1024937.
#if defined(CONF_FAMILY_WINDOWS)
	wchar_t wide_path[IO_MAX_PATH_LENGTH];
	if(GetModuleFileNameW(nullptr, wide_path, std::size(wide_path)) == 0 || GetLastError() != ERROR_SUCCESS)
	{
		return nullptr;
	}
	const std::optional<std::string> path = windows_wide_to_utf8(wide_path);
	return path.has_value() ? io_open(path.value().c_str(), IOFLAG_READ) : nullptr;
#elif defined(CONF_PLATFORM_MACOS)
	char path[IO_MAX_PATH_LENGTH];
	uint32_t path_size = sizeof(path);
	if(_NSGetExecutablePath(path, &path_size))
	{
		return 0;
	}
	return io_open(path, IOFLAG_READ);
#else
	static const char *NAMES[] = {
		"/proc/self/exe", // Linux, Android
		"/proc/curproc/exe", // NetBSD
		"/proc/curproc/file", // DragonFly
	};
	for(auto &name : NAMES)
	{
		IOHANDLE result = io_open(name, IOFLAG_READ);
		if(result)
		{
			return result;
		}
	}
	return 0;
#endif
}

#define ASYNC_BUFSIZE (8 * 1024)
#define ASYNC_LOCAL_BUFSIZE (64 * 1024)

struct ASYNCIO
{
	CLock lock;
	IOHANDLE io;
	SEMAPHORE sphore;
	void *thread;

	unsigned char *buffer;
	unsigned int buffer_size;
	unsigned int read_pos;
	unsigned int write_pos;

	int error;
	unsigned char finish;
	unsigned char refcount;
};

enum
{
	ASYNCIO_RUNNING,
	ASYNCIO_CLOSE,
	ASYNCIO_EXIT,
};

struct BUFFERS
{
	unsigned char *buf1;
	unsigned int len1;
	unsigned char *buf2;
	unsigned int len2;
};

static void buffer_ptrs(ASYNCIO *aio, struct BUFFERS *buffers)
{
	mem_zero(buffers, sizeof(*buffers));
	if(aio->read_pos < aio->write_pos)
	{
		buffers->buf1 = aio->buffer + aio->read_pos;
		buffers->len1 = aio->write_pos - aio->read_pos;
	}
	else if(aio->read_pos > aio->write_pos)
	{
		buffers->buf1 = aio->buffer + aio->read_pos;
		buffers->len1 = aio->buffer_size - aio->read_pos;
		buffers->buf2 = aio->buffer;
		buffers->len2 = aio->write_pos;
	}
}

static void aio_handle_free_and_unlock(ASYNCIO *aio) RELEASE(aio->lock)
{
	int do_free;
	aio->refcount--;

	do_free = aio->refcount == 0;
	aio->lock.unlock();
	if(do_free)
	{
		free(aio->buffer);
		sphore_destroy(&aio->sphore);
		delete aio;
	}
}

static void aio_thread(void *user)
{
	ASYNCIO *aio = (ASYNCIO *)user;

	aio->lock.lock();
	while(true)
	{
		struct BUFFERS buffers;
		int result_io_error;
		unsigned char local_buffer[ASYNC_LOCAL_BUFSIZE];
		unsigned int local_buffer_len = 0;

		if(aio->read_pos == aio->write_pos)
		{
			if(aio->finish != ASYNCIO_RUNNING)
			{
				if(aio->finish == ASYNCIO_CLOSE)
				{
					io_close(aio->io);
				}
				aio_handle_free_and_unlock(aio);
				break;
			}
			aio->lock.unlock();
			sphore_wait(&aio->sphore);
			aio->lock.lock();
			continue;
		}

		buffer_ptrs(aio, &buffers);
		if(buffers.buf1)
		{
			if(buffers.len1 > sizeof(local_buffer) - local_buffer_len)
			{
				buffers.len1 = sizeof(local_buffer) - local_buffer_len;
			}
			mem_copy(local_buffer + local_buffer_len, buffers.buf1, buffers.len1);
			local_buffer_len += buffers.len1;
			if(buffers.buf2)
			{
				if(buffers.len2 > sizeof(local_buffer) - local_buffer_len)
				{
					buffers.len2 = sizeof(local_buffer) - local_buffer_len;
				}
				mem_copy(local_buffer + local_buffer_len, buffers.buf2, buffers.len2);
				local_buffer_len += buffers.len2;
			}
		}
		aio->read_pos = (aio->read_pos + buffers.len1 + buffers.len2) % aio->buffer_size;
		aio->lock.unlock();

		io_write(aio->io, local_buffer, local_buffer_len);
		io_flush(aio->io);
		result_io_error = io_error(aio->io);

		aio->lock.lock();
		aio->error = result_io_error;
	}
}

ASYNCIO *aio_new(IOHANDLE io)
{
	ASYNCIO *aio = new ASYNCIO;
	if(!aio)
	{
		return nullptr;
	}
	aio->io = io;
	sphore_init(&aio->sphore);
	aio->thread = nullptr;

	aio->buffer = (unsigned char *)malloc(ASYNC_BUFSIZE);
	if(!aio->buffer)
	{
		sphore_destroy(&aio->sphore);
		delete aio;
		return nullptr;
	}
	aio->buffer_size = ASYNC_BUFSIZE;
	aio->read_pos = 0;
	aio->write_pos = 0;
	aio->error = 0;
	aio->finish = ASYNCIO_RUNNING;
	aio->refcount = 2;

	aio->thread = thread_init(aio_thread, aio, "aio");
	if(!aio->thread)
	{
		free(aio->buffer);
		sphore_destroy(&aio->sphore);
		delete aio;
		return nullptr;
	}
	return aio;
}

static unsigned int buffer_len(ASYNCIO *aio)
{
	if(aio->write_pos >= aio->read_pos)
	{
		return aio->write_pos - aio->read_pos;
	}
	else
	{
		return aio->buffer_size + aio->write_pos - aio->read_pos;
	}
}

static unsigned int next_buffer_size(unsigned int cur_size, unsigned int need_size)
{
	while(cur_size < need_size)
	{
		cur_size *= 2;
	}
	return cur_size;
}

void aio_lock(ASYNCIO *aio) ACQUIRE(aio->lock)
{
	aio->lock.lock();
}

void aio_unlock(ASYNCIO *aio) RELEASE(aio->lock)
{
	aio->lock.unlock();
	sphore_signal(&aio->sphore);
}

void aio_write_unlocked(ASYNCIO *aio, const void *buffer, unsigned size)
{
	unsigned int remaining;
	remaining = aio->buffer_size - buffer_len(aio);

	// Don't allow full queue to distinguish between empty and full queue.
	if(size < remaining)
	{
		unsigned int remaining_contiguous = aio->buffer_size - aio->write_pos;
		if(size > remaining_contiguous)
		{
			mem_copy(aio->buffer + aio->write_pos, buffer, remaining_contiguous);
			size -= remaining_contiguous;
			buffer = ((unsigned char *)buffer) + remaining_contiguous;
			aio->write_pos = 0;
		}
		mem_copy(aio->buffer + aio->write_pos, buffer, size);
		aio->write_pos = (aio->write_pos + size) % aio->buffer_size;
	}
	else
	{
		// Add 1 so the new buffer isn't completely filled.
		unsigned int new_written = buffer_len(aio) + size + 1;
		unsigned int next_size = next_buffer_size(aio->buffer_size, new_written);
		unsigned int next_len = 0;
		unsigned char *next_buffer = (unsigned char *)malloc(next_size);

		struct BUFFERS buffers;
		buffer_ptrs(aio, &buffers);
		if(buffers.buf1)
		{
			mem_copy(next_buffer + next_len, buffers.buf1, buffers.len1);
			next_len += buffers.len1;
			if(buffers.buf2)
			{
				mem_copy(next_buffer + next_len, buffers.buf2, buffers.len2);
				next_len += buffers.len2;
			}
		}
		mem_copy(next_buffer + next_len, buffer, size);
		next_len += size;

		free(aio->buffer);
		aio->buffer = next_buffer;
		aio->buffer_size = next_size;
		aio->read_pos = 0;
		aio->write_pos = next_len;
	}
}

void aio_write(ASYNCIO *aio, const void *buffer, unsigned size)
{
	aio_lock(aio);
	aio_write_unlocked(aio, buffer, size);
	aio_unlock(aio);
}

void aio_write_newline_unlocked(ASYNCIO *aio)
{
#if defined(CONF_FAMILY_WINDOWS)
	aio_write_unlocked(aio, "\r\n", 2);
#else
	aio_write_unlocked(aio, "\n", 1);
#endif
}

void aio_write_newline(ASYNCIO *aio)
{
	aio_lock(aio);
	aio_write_newline_unlocked(aio);
	aio_unlock(aio);
}

int aio_error(ASYNCIO *aio)
{
	CLockScope ls(aio->lock);
	return aio->error;
}

void aio_close(ASYNCIO *aio)
{
	{
		CLockScope ls(aio->lock);
		aio->finish = ASYNCIO_CLOSE;
	}
	sphore_signal(&aio->sphore);
}

void aio_wait(ASYNCIO *aio)
{
	void *thread;
	{
		CLockScope ls(aio->lock);
		thread = aio->thread;
		aio->thread = nullptr;
		if(aio->finish == ASYNCIO_RUNNING)
		{
			aio->finish = ASYNCIO_EXIT;
		}
	}
	sphore_signal(&aio->sphore);
	thread_wait(thread);
}

void aio_free(ASYNCIO *aio)
{
	aio->lock.lock();
	if(aio->thread)
	{
		thread_detach(aio->thread);
		aio->thread = nullptr;
	}
	aio_handle_free_and_unlock(aio);
}

struct THREAD_RUN
{
	void (*threadfunc)(void *);
	void *u;
};

#if defined(CONF_FAMILY_UNIX)
static void *thread_run(void *user)
#elif defined(CONF_FAMILY_WINDOWS)
static unsigned long __stdcall thread_run(void *user)
#else
#error not implemented
#endif
{
#if defined(CONF_FAMILY_WINDOWS)
	CWindowsComLifecycle WindowsComLifecycle(false);
#endif
	struct THREAD_RUN *data = (THREAD_RUN *)user;
	void (*threadfunc)(void *) = data->threadfunc;
	void *u = data->u;
	free(data);
	threadfunc(u);
	return 0;
}

void *thread_init(void (*threadfunc)(void *), void *u, const char *name)
{
	struct THREAD_RUN *data = (THREAD_RUN *)malloc(sizeof(*data));
	data->threadfunc = threadfunc;
	data->u = u;
#if defined(CONF_FAMILY_UNIX)
	{
		pthread_attr_t attr;
		dbg_assert(pthread_attr_init(&attr) == 0, "pthread_attr_init failure");
#if defined(CONF_PLATFORM_MACOS) && defined(__MAC_10_10) && __MAC_OS_X_VERSION_MIN_REQUIRED >= __MAC_10_10
		dbg_assert(pthread_attr_set_qos_class_np(&attr, QOS_CLASS_USER_INTERACTIVE, 0) == 0, "pthread_attr_set_qos_class_np failure");
#endif
		pthread_t id;
		dbg_assert(pthread_create(&id, &attr, thread_run, data) == 0, "pthread_create failure");
#if defined(CONF_PLATFORM_EMSCRIPTEN)
		// Return control to the browser's main thread to allow the pthread to be started,
		// otherwise we deadlock when waiting for a thread immediately after starting it.
		emscripten_sleep(0);
#endif
		return (void *)id;
	}
#elif defined(CONF_FAMILY_WINDOWS)
	HANDLE thread = CreateThread(nullptr, 0, thread_run, data, 0, nullptr);
	dbg_assert(thread != nullptr, "CreateThread failure");
	HMODULE kernel_base_handle;
	if(GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_PIN, L"KernelBase.dll", &kernel_base_handle))
	{
		// Intentional
#ifdef __MINGW32__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-function-type"
#endif
		auto set_thread_description_function = reinterpret_cast<HRESULT(WINAPI *)(HANDLE, PCWSTR)>(GetProcAddress(kernel_base_handle, "SetThreadDescription"));
#ifdef __MINGW32__
#pragma GCC diagnostic pop
#endif
		if(set_thread_description_function)
			set_thread_description_function(thread, windows_utf8_to_wide(name).c_str());
	}
	return thread;
#else
#error not implemented
#endif
}

void thread_wait(void *thread)
{
#if defined(CONF_FAMILY_UNIX)
	dbg_assert(pthread_join((pthread_t)thread, nullptr) == 0, "pthread_join failure");
#elif defined(CONF_FAMILY_WINDOWS)
	dbg_assert(WaitForSingleObject((HANDLE)thread, INFINITE) == WAIT_OBJECT_0, "WaitForSingleObject failure");
	dbg_assert(CloseHandle(thread), "CloseHandle failure");
#else
#error not implemented
#endif
}

void thread_yield()
{
#if defined(CONF_FAMILY_UNIX)
	dbg_assert(sched_yield() == 0, "sched_yield failure");
#elif defined(CONF_FAMILY_WINDOWS)
	Sleep(0);
#else
#error not implemented
#endif
}

void thread_detach(void *thread)
{
#if defined(CONF_FAMILY_UNIX)
	dbg_assert(pthread_detach((pthread_t)thread) == 0, "pthread_detach failure");
#elif defined(CONF_FAMILY_WINDOWS)
	dbg_assert(CloseHandle(thread), "CloseHandle failure");
#else
#error not implemented
#endif
}

void thread_init_and_detach(void (*threadfunc)(void *), void *u, const char *name)
{
	void *thread = thread_init(threadfunc, u, name);
	thread_detach(thread);
}

#if defined(CONF_FAMILY_WINDOWS)
void sphore_init(SEMAPHORE *sem)
{
	*sem = CreateSemaphoreW(nullptr, 0, std::numeric_limits<LONG>::max(), nullptr);
	dbg_assert(*sem != nullptr, "CreateSemaphoreW failure");
}
void sphore_wait(SEMAPHORE *sem)
{
	dbg_assert(WaitForSingleObject((HANDLE)*sem, INFINITE) == WAIT_OBJECT_0, "WaitForSingleObject failure");
}
void sphore_signal(SEMAPHORE *sem)
{
	dbg_assert(ReleaseSemaphore((HANDLE)*sem, 1, nullptr), "ReleaseSemaphore failure");
}
void sphore_destroy(SEMAPHORE *sem)
{
	dbg_assert(CloseHandle((HANDLE)*sem), "CloseHandle failure");
}
#elif defined(CONF_PLATFORM_MACOS)
void sphore_init(SEMAPHORE *sem)
{
	char aBuf[64];
	str_format(aBuf, sizeof(aBuf), "/%d.%p", pid(), (void *)sem);
	*sem = sem_open(aBuf, O_CREAT | O_EXCL, S_IRWXU | S_IRWXG, 0);
	dbg_assert(*sem != SEM_FAILED, "sem_open failure, errno=%d, name='%s'", errno, aBuf);
}
void sphore_wait(SEMAPHORE *sem)
{
	while(true)
	{
		if(sem_wait(*sem) == 0)
			break;
		dbg_assert(errno == EINTR, "sem_wait failure");
	}
}
void sphore_signal(SEMAPHORE *sem)
{
	dbg_assert(sem_post(*sem) == 0, "sem_post failure");
}
void sphore_destroy(SEMAPHORE *sem)
{
	dbg_assert(sem_close(*sem) == 0, "sem_close failure");
	char aBuf[64];
	str_format(aBuf, sizeof(aBuf), "/%d.%p", pid(), (void *)sem);
	dbg_assert(sem_unlink(aBuf) == 0, "sem_unlink failure");
}
#elif defined(CONF_FAMILY_UNIX)
void sphore_init(SEMAPHORE *sem)
{
	dbg_assert(sem_init(sem, 0, 0) == 0, "sem_init failure");
}
void sphore_wait(SEMAPHORE *sem)
{
	while(true)
	{
		if(sem_wait(sem) == 0)
			break;
		dbg_assert(errno == EINTR, "sem_wait failure");
	}
}
void sphore_signal(SEMAPHORE *sem)
{
	dbg_assert(sem_post(sem) == 0, "sem_post failure");
}
void sphore_destroy(SEMAPHORE *sem)
{
	dbg_assert(sem_destroy(sem) == 0, "sem_destroy failure");
}
#endif

/* -----  network ----- */

const NETADDR NETADDR_ZEROED = {NETTYPE_INVALID, {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, 0};

static void netaddr_to_sockaddr_in(const NETADDR *src, sockaddr_in *dest)
{
	dbg_assert((src->type & NETTYPE_IPV4) != 0, "Invalid address type '%d' for netaddr_to_sockaddr_in", src->type);
	mem_zero(dest, sizeof(*dest));
	dest->sin_family = AF_INET;
	dest->sin_port = htons(src->port);
	mem_copy(&dest->sin_addr.s_addr, src->ip, 4);
}

static void netaddr_to_sockaddr_in6(const NETADDR *src, sockaddr_in6 *dest)
{
	dbg_assert((src->type & NETTYPE_IPV6) != 0, "Invalid address type '%d' for netaddr_to_sockaddr_in6", src->type);
	mem_zero(dest, sizeof(*dest));
	dest->sin6_family = AF_INET6;
	dest->sin6_port = htons(src->port);
	mem_copy(&dest->sin6_addr.s6_addr, src->ip, 16);
}

static void sockaddr_to_netaddr(const sockaddr *src, socklen_t src_len, NETADDR *dst)
{
	*dst = NETADDR_ZEROED;
	if(src->sa_family == AF_INET && src_len >= (socklen_t)sizeof(sockaddr_in))
	{
		const sockaddr_in *src_in = (const sockaddr_in *)src;
		dst->type = NETTYPE_IPV4;
		dst->port = htons(src_in->sin_port);
		static_assert(sizeof(dst->ip) >= sizeof(src_in->sin_addr.s_addr));
		mem_copy(dst->ip, &src_in->sin_addr.s_addr, sizeof(src_in->sin_addr.s_addr));
	}
	else if(src->sa_family == AF_INET6 && src_len >= (socklen_t)sizeof(sockaddr_in6))
	{
		const sockaddr_in6 *src_in6 = (const sockaddr_in6 *)src;
		dst->type = NETTYPE_IPV6;
		dst->port = htons(src_in6->sin6_port);
		static_assert(sizeof(dst->ip) >= sizeof(src_in6->sin6_addr.s6_addr));
		mem_copy(dst->ip, &src_in6->sin6_addr.s6_addr, sizeof(src_in6->sin6_addr.s6_addr));
	}
	else
	{
		log_warn("net", "Cannot convert sockaddr of family %d", src->sa_family);
	}
}

int net_addr_comp(const NETADDR *a, const NETADDR *b)
{
	int diff = a->type - b->type;
	if(diff != 0)
	{
		return diff;
	}
	diff = mem_comp(a->ip, b->ip, sizeof(a->ip));
	if(diff != 0)
	{
		return diff;
	}
	return a->port - b->port;
}

bool NETADDR::operator==(const NETADDR &other) const
{
	return net_addr_comp(this, &other) == 0;
}

bool NETADDR::operator!=(const NETADDR &other) const
{
	return net_addr_comp(this, &other) != 0;
}

bool NETADDR::operator<(const NETADDR &other) const
{
	return net_addr_comp(this, &other) < 0;
}

size_t std::hash<NETADDR>::operator()(const NETADDR &Addr) const noexcept
{
	size_t seed = std::hash<unsigned int>{}(Addr.type);
	seed ^= std::hash<std::string_view>{}(std::string_view(reinterpret_cast<const char *>(Addr.ip), sizeof(Addr.ip))) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
	seed ^= std::hash<unsigned short>{}(Addr.port) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
	return seed;
}

int net_addr_comp_noport(const NETADDR *a, const NETADDR *b)
{
	int diff = a->type - b->type;
	if(diff != 0)
	{
		return diff;
	}
	return mem_comp(a->ip, b->ip, sizeof(a->ip));
}

void net_addr_str_v6(const unsigned short ip[8], int port, char *buffer, int buffer_size)
{
	int longest_seq_len = 0;
	int longest_seq_start = -1;
	int w = 0;
	int i;
	{
		int seq_len = 0;
		int seq_start = -1;
		// Determine longest sequence of zeros.
		for(i = 0; i < 8 + 1; i++)
		{
			if(seq_start != -1)
			{
				if(i == 8 || ip[i] != 0)
				{
					if(longest_seq_len < seq_len)
					{
						longest_seq_len = seq_len;
						longest_seq_start = seq_start;
					}
					seq_len = 0;
					seq_start = -1;
				}
				else
				{
					seq_len += 1;
				}
			}
			else
			{
				if(i != 8 && ip[i] == 0)
				{
					seq_start = i;
					seq_len = 1;
				}
			}
		}
	}
	if(longest_seq_len <= 1)
	{
		longest_seq_len = 0;
		longest_seq_start = -1;
	}
	w += str_copy(buffer + w, "[", buffer_size - w);
	for(i = 0; i < 8; i++)
	{
		if(longest_seq_start <= i && i < longest_seq_start + longest_seq_len)
		{
			if(i == longest_seq_start)
			{
				w += str_copy(buffer + w, "::", buffer_size - w);
			}
		}
		else
		{
			const char *colon = (i == 0 || i == longest_seq_start + longest_seq_len) ? "" : ":";
			w += str_format(buffer + w, buffer_size - w, "%s%x", colon, ip[i]);
		}
	}
	w += str_copy(buffer + w, "]", buffer_size - w);
	if(port >= 0)
	{
		str_format(buffer + w, buffer_size - w, ":%d", port);
	}
}

void net_addr_str(const NETADDR *addr, char *string, int max_length, bool add_port)
{
	if((addr->type & (NETTYPE_IPV4 | NETTYPE_WEBSOCKET_IPV4)) != 0)
	{
		if(add_port)
		{
			str_format(string, max_length, "%d.%d.%d.%d:%d", addr->ip[0], addr->ip[1], addr->ip[2], addr->ip[3], addr->port);
		}
		else
		{
			str_format(string, max_length, "%d.%d.%d.%d", addr->ip[0], addr->ip[1], addr->ip[2], addr->ip[3]);
		}
	}
	else if((addr->type & (NETTYPE_IPV6 | NETTYPE_WEBSOCKET_IPV6)) != 0)
	{
		unsigned short ip[8];
		for(int i = 0; i < 8; i++)
		{
			ip[i] = (addr->ip[i * 2] << 8) | (addr->ip[i * 2 + 1]);
		}
		int port = add_port ? addr->port : -1;
		net_addr_str_v6(ip, port, string, max_length);
	}
	else
	{
		dbg_assert_failed("unknown NETADDR type %d", addr->type);
	}
}

static int priv_net_extract(const char *hostname, char *host, int max_host, int *port)
{
	*port = 0;
	host[0] = 0;

	if(hostname[0] == '[')
	{
		// ipv6 mode
		int i;
		for(i = 1; i < max_host && hostname[i] && hostname[i] != ']'; i++)
			host[i - 1] = hostname[i];
		host[i - 1] = 0;
		if(hostname[i] != ']') // malformatted
			return -1;

		i++;
		if(hostname[i] == ':')
			*port = str_toint(hostname + i + 1);
	}
	else
	{
		// generic mode (ipv4, hostname etc)
		int i;
		for(i = 0; i < max_host - 1 && hostname[i] && hostname[i] != ':'; i++)
			host[i] = hostname[i];
		host[i] = 0;

		if(hostname[i] == ':')
			*port = str_toint(hostname + i + 1);
	}

	return 0;
}

static int net_host_lookup_fallback(const char *hostname, NETADDR *addr, int types, int port)
{
	if(str_comp_nocase(hostname, "localhost") == 0)
	{
		if(types == NETTYPE_IPV4)
		{
			dbg_assert(net_addr_from_str(addr, "127.0.0.1") == 0, "unreachable");
			addr->port = port;
			return 0;
		}
		else if(types == NETTYPE_IPV6)
		{
			dbg_assert(net_addr_from_str(addr, "[::1]") == 0, "unreachable");
			addr->port = port;
			return 0;
		}
		else
		{
			// TODO: return both IPv4 and IPv6 address
			dbg_assert(net_addr_from_str(addr, "127.0.0.1") == 0, "unreachable");
			addr->port = port;
			return 0;
		}
	}
	return -1;
}

static int net_host_lookup_impl(const char *hostname, NETADDR *addr, int types)
{
	char host[256];
	int port = 0;
	if(priv_net_extract(hostname, host, sizeof(host), &port))
		return -1;

	log_trace("host_lookup", "host='%s' port='%d' types='%d'", host, port, types);

	struct addrinfo hints;
	mem_zero(&hints, sizeof(hints));

	if(types == NETTYPE_IPV4)
		hints.ai_family = AF_INET;
	else if(types == NETTYPE_IPV6)
		hints.ai_family = AF_INET6;
	else
		hints.ai_family = AF_UNSPEC;

	struct addrinfo *result = nullptr;
	int e = getaddrinfo(host, nullptr, &hints, &result);
	if(!result)
	{
		return net_host_lookup_fallback(hostname, addr, types, port);
	}

	if(e != 0)
	{
		freeaddrinfo(result);
		return net_host_lookup_fallback(hostname, addr, types, port);
	}

	sockaddr_to_netaddr(result->ai_addr, result->ai_addrlen, addr);
	addr->port = port;
	freeaddrinfo(result);
	return 0;
}

int net_host_lookup(const char *hostname, NETADDR *addr, int types)
{
	const char *ws_hostname = str_startswith(hostname, "ws://");
	if(ws_hostname)
	{
		if((types & (NETTYPE_WEBSOCKET_IPV4 | NETTYPE_WEBSOCKET_IPV6)) == 0)
		{
			return -1;
		}
		int result = net_host_lookup_impl(ws_hostname, addr, types & ~(NETTYPE_WEBSOCKET_IPV4 | NETTYPE_WEBSOCKET_IPV6));
		if(result == 0)
		{
			if(addr->type == NETTYPE_IPV4)
			{
				addr->type = NETTYPE_WEBSOCKET_IPV4;
			}
			else if(addr->type == NETTYPE_IPV6)
			{
				addr->type = NETTYPE_WEBSOCKET_IPV6;
			}
		}
		return result;
	}
	return net_host_lookup_impl(hostname, addr, types & ~(NETTYPE_WEBSOCKET_IPV4 | NETTYPE_WEBSOCKET_IPV6));
}

static int parse_int(int *out, const char **str)
{
	int i = 0;
	*out = 0;
	if(!str_isnum(**str))
		return -1;

	i = **str - '0';
	(*str)++;

	while(true)
	{
		if(!str_isnum(**str))
		{
			*out = i;
			return 0;
		}

		i = (i * 10) + (**str - '0');
		(*str)++;
	}

	return 0;
}

static int parse_char(char c, const char **str)
{
	if(**str != c)
		return -1;
	(*str)++;
	return 0;
}

static int parse_uint8(unsigned char *out, const char **str)
{
	int i;
	if(parse_int(&i, str) != 0)
		return -1;
	if(i < 0 || i > 0xff)
		return -1;
	*out = i;
	return 0;
}

static int parse_uint16(unsigned short *out, const char **str)
{
	int i;
	if(parse_int(&i, str) != 0)
		return -1;
	if(i < 0 || i > 0xffff)
		return -1;
	*out = i;
	return 0;
}

int net_addr_from_url(NETADDR *addr, const char *string, char *host_buf, size_t host_buf_size)
{
	bool sixup = false;
	mem_zero(addr, sizeof(*addr));
	const char *str = str_startswith(string, "tw-0.6+udp://");
	if(!str && (str = str_startswith(string, "tw-0.7+udp://")))
	{
		addr->type |= NETTYPE_TW7;
		sixup = true;
	}
	if(!str)
		return 1;

	int length = str_length(str);
	int start = 0;
	int end = length;
	for(int i = 0; i < length; i++)
	{
		if(str[i] == '@')
		{
			if(start != 0)
			{
				// Two at signs.
				return true;
			}
			start = i + 1;
		}
		else if(str[i] == '/' || str[i] == '?' || str[i] == '#')
		{
			end = i;
			break;
		}
	}

	char host[128];
	str_truncate(host, sizeof(host), str + start, end - start);
	if(host_buf)
		str_copy(host_buf, host, host_buf_size);

	int failure = net_addr_from_str(addr, host);
	if(failure)
		return failure;

	if(sixup)
		addr->type |= NETTYPE_TW7;

	return failure;
}

bool net_addr_is_local(const NETADDR *addr)
{
	char addr_str[NETADDR_MAXSTRSIZE];
	net_addr_str(addr, addr_str, sizeof(addr_str), true);

	if(addr->ip[0] == 127 || addr->ip[0] == 10 || (addr->ip[0] == 192 && addr->ip[1] == 168) || (addr->ip[0] == 172 && (addr->ip[1] >= 16 && addr->ip[1] <= 31)))
		return true;

	if(str_startswith(addr_str, "[fe80:") || str_startswith(addr_str, "[::1"))
		return true;

	return false;
}

int net_addr_from_str(NETADDR *addr, const char *string)
{
	const char *str = string;
	mem_zero(addr, sizeof(NETADDR));

	if(str[0] == '[')
	{
		/* ipv6 */
		sockaddr_in6 sa6;
		char buf[128];
		int i;
		str++;
		for(i = 0; i < 127 && str[i] && str[i] != ']'; i++)
			buf[i] = str[i];
		buf[i] = 0;
		str += i;
#if defined(CONF_FAMILY_WINDOWS)
		{
			int size;
			sa6.sin6_family = AF_INET6;
			size = (int)sizeof(sa6);
			if(WSAStringToAddressA(buf, AF_INET6, nullptr, (sockaddr *)&sa6, &size) != 0)
				return -1;
		}
#else
		sa6.sin6_family = AF_INET6;

		if(inet_pton(AF_INET6, buf, &sa6.sin6_addr) != 1)
			return -1;
#endif
		sockaddr_to_netaddr((sockaddr *)&sa6, sizeof(sa6), addr);

		if(*str == ']')
		{
			str++;
			if(*str == ':')
			{
				str++;
				if(parse_uint16(&addr->port, &str))
					return -1;
			}
			else
			{
				addr->port = 0;
			}
		}
		else
			return -1;

		return 0;
	}
	else
	{
		/* ipv4 */
		if(parse_uint8(&addr->ip[0], &str))
			return -1;
		if(parse_char('.', &str))
			return -1;
		if(parse_uint8(&addr->ip[1], &str))
			return -1;
		if(parse_char('.', &str))
			return -1;
		if(parse_uint8(&addr->ip[2], &str))
			return -1;
		if(parse_char('.', &str))
			return -1;
		if(parse_uint8(&addr->ip[3], &str))
			return -1;
		if(*str == ':')
		{
			str++;
			if(parse_uint16(&addr->port, &str))
				return -1;
		}
		if(*str != '\0')
			return -1;

		addr->type = NETTYPE_IPV4;
	}

	return 0;
}

static void priv_net_close_socket(int sock)
{
#if defined(CONF_FAMILY_WINDOWS)
	dbg_assert(closesocket(sock) == 0, "closesocket failure (%s)", net_error_message().c_str());
#else
	dbg_assert(close(sock) == 0, "close failure (%s)", net_error_message().c_str());
#endif
}

static void priv_net_close_all_sockets(NETSOCKET sock)
{
	if(sock->ipv4sock >= 0)
	{
		priv_net_close_socket(sock->ipv4sock);
		sock->ipv4sock = -1;
		sock->type &= ~NETTYPE_IPV4;
	}

#if defined(CONF_WEBSOCKETS)
	if(sock->web_ipv4sock >= 0)
	{
		websocket_destroy(sock->web_ipv4sock);
		sock->web_ipv4sock = -1;
		sock->type &= ~NETTYPE_WEBSOCKET_IPV4;
	}
#endif

	if(sock->ipv6sock >= 0)
	{
		priv_net_close_socket(sock->ipv6sock);
		sock->ipv6sock = -1;
		sock->type &= ~NETTYPE_IPV6;
	}

#if defined(CONF_WEBSOCKETS)
	if(sock->web_ipv6sock >= 0)
	{
		websocket_destroy(sock->web_ipv6sock);
		sock->web_ipv6sock = -1;
		sock->type &= ~NETTYPE_WEBSOCKET_IPV6;
	}
#endif

	free(sock);
}

static int priv_net_create_socket(int domain, int type, const NETADDR *bindaddr)
{
	int sock = socket(domain, type, 0);
	if(sock < 0)
	{
		log_error("net", "Failed to create socket with domain %d and type %d (%s)", domain, type, net_error_message().c_str());
		return -1;
	}

#if defined(CONF_FAMILY_UNIX)
	// On TCP sockets set SO_REUSEADDR to fix port rebind on restart
	if(domain == AF_INET && type == SOCK_STREAM)
	{
		int reuse_addr = 1;
		if(setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char *)&reuse_addr, sizeof(reuse_addr)) != 0)
		{
			log_error("net", "Setting SO_REUSEADDR failed with domain %d and type %d (%s)", domain, type, net_error_message().c_str());
		}
	}
#elif defined(CONF_FAMILY_WINDOWS)
	{
		// Ensure exclusive use of address, otherwise it's possible on Windows to bind to the same address and port with another socket.
		// See https://learn.microsoft.com/en-us/windows/win32/winsock/using-so-reuseaddr-and-so-exclusiveaddruse (last update 06/14/2022)
		int exclusive_addr_use = 1;
		if(setsockopt(sock, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (const char *)&exclusive_addr_use, sizeof(exclusive_addr_use)) != 0)
		{
			log_error("net", "Setting SO_EXCLUSIVEADDRUSE failed with domain %d and type %d (%s)", domain, type, net_error_message().c_str());
		}
	}
#endif

	// Set to IPv6-only if that's what we are creating, to ensure that dual-stack does not block the same IPv4 port.
#if defined(IPV6_V6ONLY)
	if(domain == AF_INET6)
	{
		int ipv6only = 1;
		if(setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (const char *)&ipv6only, sizeof(ipv6only)) != 0)
		{
			log_error("net", "Setting IPV6_V6ONLY failed with domain %d and type %d (%s)", domain, type, net_error_message().c_str());
		}
	}
#endif

	sockaddr_storage addr;
	socklen_t addr_len;
	if(bindaddr->type == NETTYPE_IPV4)
	{
		netaddr_to_sockaddr_in(bindaddr, (sockaddr_in *)&addr);
		addr_len = sizeof(sockaddr_in);
	}
	else if(bindaddr->type == NETTYPE_IPV6)
	{
		netaddr_to_sockaddr_in6(bindaddr, (sockaddr_in6 *)&addr);
		addr_len = sizeof(sockaddr_in6);
	}
	else
	{
		dbg_assert_failed("socket type invalid: %d", type);
	}

	if(bind(sock, (sockaddr *)&addr, addr_len) != 0)
	{
		log_error("net", "Failed to bind socket with domain %d and type %d (%s)", domain, type, net_error_message().c_str());
		priv_net_close_socket(sock);
		return -1;
	}

	return sock;
}

int net_socket_type(NETSOCKET sock)
{
	return sock->type;
}

NETSOCKET net_udp_create(NETADDR bindaddr)
{
	NETSOCKET sock = (NETSOCKET_INTERNAL *)malloc(sizeof(*sock));
	*sock = invalid_socket;

	if(bindaddr.type & NETTYPE_IPV4)
	{
		NETADDR bindaddr_ipv4 = bindaddr;
		bindaddr_ipv4.type = NETTYPE_IPV4;
		const int socket = priv_net_create_socket(AF_INET, SOCK_DGRAM, &bindaddr_ipv4);
		if(socket >= 0)
		{
			sock->type |= NETTYPE_IPV4;
			sock->ipv4sock = socket;

			// Set broadcast
			{
				int broadcast = 1;
				if(setsockopt(socket, SOL_SOCKET, SO_BROADCAST, (const char *)&broadcast, sizeof(broadcast)) != 0)
				{
					log_error("net", "Setting SO_BROADCAST on IPv4 failed (%s)", net_error_message().c_str());
				}
			}

			// Set DSCP/TOS
			{
				int iptos = 0x10; // IPTOS_LOWDELAY
				if(setsockopt(socket, IPPROTO_IP, IP_TOS, (const char *)&iptos, sizeof(iptos)) != 0)
				{
					log_error("net", "Setting IP_TOS on IPv4 failed (%s)", net_error_message().c_str());
				}
			}
		}
	}

#if defined(CONF_WEBSOCKETS)
	if(bindaddr.type & NETTYPE_WEBSOCKET_IPV4)
	{
		NETADDR bindaddr_websocket_ipv4 = bindaddr;
		bindaddr_websocket_ipv4.type = NETTYPE_WEBSOCKET_IPV4;
		const int socket = websocket_create(&bindaddr_websocket_ipv4);
		if(socket >= 0)
		{
			sock->type |= NETTYPE_WEBSOCKET_IPV4;
			sock->web_ipv4sock = socket;
		}
	}
#endif

	if(bindaddr.type & NETTYPE_IPV6)
	{
		NETADDR bindaddr_ipv6 = bindaddr;
		bindaddr_ipv6.type = NETTYPE_IPV6;
		const int socket = priv_net_create_socket(AF_INET6, SOCK_DGRAM, &bindaddr_ipv6);
		if(socket >= 0)
		{
			sock->type |= NETTYPE_IPV6;
			sock->ipv6sock = socket;

			// Set broadcast
			{
				int broadcast = 1;
				if(setsockopt(socket, SOL_SOCKET, SO_BROADCAST, (const char *)&broadcast, sizeof(broadcast)) != 0)
				{
					log_error("net", "Setting SO_BROADCAST on IPv6 failed (%s)", net_error_message().c_str());
				}
			}

			// Set DSCP/TOS
			// TODO: setting IP_TOS on ipv6 with setsockopt is not supported on Windows, see https://github.com/ddnet/ddnet/issues/7605
#if !defined(CONF_FAMILY_WINDOWS)
			{
				int iptos = 0x10; // IPTOS_LOWDELAY
				if(setsockopt(socket, IPPROTO_IP, IP_TOS, (const char *)&iptos, sizeof(iptos)) != 0)
				{
					log_error("net", "Setting IP_TOS on IPv6 failed (%s)", net_error_message().c_str());
				}
			}
#endif
		}
	}

#if defined(CONF_WEBSOCKETS)
	if(bindaddr.type & NETTYPE_WEBSOCKET_IPV6)
	{
		NETADDR bindaddr_websocket_ipv6 = bindaddr;
		bindaddr_websocket_ipv6.type = NETTYPE_WEBSOCKET_IPV6;
		const int socket = websocket_create(&bindaddr_websocket_ipv6);
		if(socket >= 0)
		{
			sock->type |= NETTYPE_WEBSOCKET_IPV6;
			sock->web_ipv6sock = socket;
		}
	}
#endif

	if(sock->type == NETTYPE_INVALID)
	{
		free(sock);
		sock = nullptr;
	}
	else
	{
		net_set_non_blocking(sock);
		net_buffer_init(&sock->buffer);
	}

	return sock;
}

int net_udp_send(NETSOCKET sock, const NETADDR *addr, const void *data, int size)
{
	int d = -1;

	if(addr->type & NETTYPE_IPV4)
	{
		if(sock->ipv4sock >= 0)
		{
			sockaddr_in sa;
			if(addr->type & NETTYPE_LINK_BROADCAST)
			{
				mem_zero(&sa, sizeof(sa));
				sa.sin_port = htons(addr->port);
				sa.sin_family = AF_INET;
				sa.sin_addr.s_addr = INADDR_BROADCAST;
			}
			else
			{
				netaddr_to_sockaddr_in(addr, &sa);
			}

			d = sendto(sock->ipv4sock, (const char *)data, size, 0, (sockaddr *)&sa, sizeof(sa));
		}
		else
		{
			log_error("net", "Cannot send IPv4 traffic to this socket");
		}
	}

#if defined(CONF_WEBSOCKETS)
	if(addr->type & NETTYPE_WEBSOCKET_IPV4)
	{
		if(sock->web_ipv4sock >= 0)
		{
			if(addr->type & NETTYPE_LINK_BROADCAST)
			{
				log_error("net", "Cannot send broadcasts to Websocket IPv4");
			}
			else
			{
				d = websocket_send(sock->web_ipv4sock, (const unsigned char *)data, size, addr);
			}
		}
		else
		{
			log_error("net", "Cannot send Websocket IPv4 traffic to this socket");
		}
	}
#endif

	if(addr->type & NETTYPE_IPV6)
	{
		if(sock->ipv6sock >= 0)
		{
			sockaddr_in6 sa;
			if(addr->type & NETTYPE_LINK_BROADCAST)
			{
				mem_zero(&sa, sizeof(sa));
				sa.sin6_port = htons(addr->port);
				sa.sin6_family = AF_INET6;
				sa.sin6_addr.s6_addr[0] = 0xff; /* multicast */
				sa.sin6_addr.s6_addr[1] = 0x02; /* link local scope */
				sa.sin6_addr.s6_addr[15] = 1; /* all nodes */
			}
			else
			{
				netaddr_to_sockaddr_in6(addr, &sa);
			}

			d = sendto(sock->ipv6sock, (const char *)data, size, 0, (sockaddr *)&sa, sizeof(sa));
		}
		else
		{
			log_error("net", "Cannot send IPv6 traffic to this socket");
		}
	}

#if defined(CONF_WEBSOCKETS)
	if(addr->type & NETTYPE_WEBSOCKET_IPV6)
	{
		if(sock->web_ipv6sock >= 0)
		{
			if(addr->type & NETTYPE_LINK_BROADCAST)
			{
				log_error("net", "Cannot send broadcasts to Websocket IPv6");
			}
			else
			{
				d = websocket_send(sock->web_ipv6sock, (const unsigned char *)data, size, addr);
			}
		}
		else
		{
			log_error("net", "Cannot send Websocket IPv6 traffic to this socket");
		}
	}
#endif

	network_stats.sent_bytes += size;
	network_stats.sent_packets++;
	return d;
}

void net_buffer_init(NETSOCKET_BUFFER *buffer)
{
#if defined(CONF_PLATFORM_LINUX)
	buffer->pos = 0;
	buffer->size = 0;
	mem_zero(buffer->msgs, sizeof(buffer->msgs));
	mem_zero(buffer->iovecs, sizeof(buffer->iovecs));
	mem_zero(buffer->sockaddrs, sizeof(buffer->sockaddrs));
	for(int i = 0; i < VLEN; ++i)
	{
		buffer->iovecs[i].iov_base = buffer->bufs[i];
		buffer->iovecs[i].iov_len = PACKETSIZE;
		buffer->msgs[i].msg_hdr.msg_iov = &(buffer->iovecs[i]);
		buffer->msgs[i].msg_hdr.msg_iovlen = 1;
		buffer->msgs[i].msg_hdr.msg_name = &(buffer->sockaddrs[i]);
		buffer->msgs[i].msg_hdr.msg_namelen = sizeof(buffer->sockaddrs[i]);
	}
#endif
}

void net_buffer_reinit(NETSOCKET_BUFFER *buffer)
{
#if defined(CONF_PLATFORM_LINUX)
	for(int i = 0; i < VLEN; i++)
	{
		buffer->msgs[i].msg_hdr.msg_namelen = sizeof(buffer->sockaddrs[i]);
	}
#endif
}

void net_buffer_simple(NETSOCKET_BUFFER *buffer, char **buf, int *size)
{
#if defined(CONF_PLATFORM_LINUX)
	*buf = buffer->bufs[0];
	*size = sizeof(buffer->bufs[0]);
#else
	*buf = buffer->buf;
	*size = sizeof(buffer->buf);
#endif
}

int net_udp_recv(NETSOCKET sock, NETADDR *addr, unsigned char **data)
{
	static const auto &&update_stats = [](int bytes) {
		network_stats.recv_bytes += bytes;
		network_stats.recv_packets++;
	};

	int bytes = 0;
#if defined(CONF_PLATFORM_LINUX)
	if(sock->ipv4sock >= 0)
	{
		if(sock->buffer.pos >= sock->buffer.size)
		{
			net_buffer_reinit(&sock->buffer);
			sock->buffer.size = recvmmsg(sock->ipv4sock, sock->buffer.msgs, VLEN, 0, NULL);
			sock->buffer.pos = 0;
		}
	}

	if(sock->ipv6sock >= 0)
	{
		if(sock->buffer.pos >= sock->buffer.size)
		{
			net_buffer_reinit(&sock->buffer);
			sock->buffer.size = recvmmsg(sock->ipv6sock, sock->buffer.msgs, VLEN, 0, NULL);
			sock->buffer.pos = 0;
		}
	}

	if(sock->buffer.pos < sock->buffer.size)
	{
		sockaddr_to_netaddr((sockaddr *)&(sock->buffer.sockaddrs[sock->buffer.pos]), sizeof(sock->buffer.sockaddrs[sock->buffer.pos]), addr);
		bytes = sock->buffer.msgs[sock->buffer.pos].msg_len;
		*data = (unsigned char *)sock->buffer.bufs[sock->buffer.pos];
		sock->buffer.pos++;
		update_stats(bytes);
		return bytes;
	}
#else
	if(sock->ipv4sock >= 0)
	{
		sockaddr_storage recv_addr;
		socklen_t fromlen = sizeof(recv_addr);
		bytes = recvfrom(sock->ipv4sock, sock->buffer.buf, sizeof(sock->buffer.buf), 0, (sockaddr *)&recv_addr, &fromlen);
		*data = (unsigned char *)sock->buffer.buf;
		if(bytes > 0)
		{
			sockaddr_to_netaddr((sockaddr *)&recv_addr, fromlen, addr);
			update_stats(bytes);
			return bytes;
		}
	}

	if(sock->ipv6sock >= 0)
	{
		sockaddr_storage recv_addr;
		socklen_t fromlen = sizeof(recv_addr);
		bytes = recvfrom(sock->ipv6sock, sock->buffer.buf, sizeof(sock->buffer.buf), 0, (sockaddr *)&recv_addr, &fromlen);
		*data = (unsigned char *)sock->buffer.buf;
		if(bytes > 0)
		{
			sockaddr_to_netaddr((sockaddr *)&recv_addr, fromlen, addr);
			update_stats(bytes);
			return bytes;
		}
	}
#endif

#if defined(CONF_WEBSOCKETS)
	if(sock->web_ipv4sock >= 0)
	{
		char *buf;
		int size;
		net_buffer_simple(&sock->buffer, &buf, &size);
		bytes = websocket_recv(sock->web_ipv4sock, (unsigned char *)buf, size, addr);
		*data = (unsigned char *)buf;
		if(bytes > 0)
		{
			update_stats(bytes);
			return bytes;
		}
	}

	if(sock->web_ipv6sock >= 0)
	{
		char *buf;
		int size;
		net_buffer_simple(&sock->buffer, &buf, &size);
		bytes = websocket_recv(sock->web_ipv6sock, (unsigned char *)buf, size, addr);
		*data = (unsigned char *)buf;
		if(bytes > 0)
		{
			update_stats(bytes);
			return bytes;
		}
	}
#endif

	return bytes < 0 ? -1 : 0;
}

void net_udp_close(NETSOCKET sock)
{
	priv_net_close_all_sockets(sock);
}

NETSOCKET net_tcp_create(NETADDR bindaddr)
{
	NETSOCKET sock = (NETSOCKET_INTERNAL *)malloc(sizeof(*sock));
	*sock = invalid_socket;

	if(bindaddr.type & NETTYPE_IPV4)
	{
		NETADDR bindaddr_ipv4 = bindaddr;
		bindaddr_ipv4.type = NETTYPE_IPV4;
		const int socket4 = priv_net_create_socket(AF_INET, SOCK_STREAM, &bindaddr_ipv4);
		if(socket4 >= 0)
		{
			sock->type |= NETTYPE_IPV4;
			sock->ipv4sock = socket4;
		}
	}

	if(bindaddr.type & NETTYPE_IPV6)
	{
		NETADDR bindaddr_ipv6 = bindaddr;
		bindaddr_ipv6.type = NETTYPE_IPV6;
		const int socket6 = priv_net_create_socket(AF_INET6, SOCK_STREAM, &bindaddr_ipv6);
		if(socket6 >= 0)
		{
			sock->type |= NETTYPE_IPV6;
			sock->ipv6sock = socket6;
		}
	}

	if(sock->type == NETTYPE_INVALID)
	{
		free(sock);
		sock = nullptr;
	}

	return sock;
}

static int net_set_blocking_impl(NETSOCKET sock, bool blocking)
{
	unsigned long mode = blocking ? 0 : 1;
	const char *mode_str = blocking ? "blocking" : "non-blocking";
	int sockets[] = {sock->ipv4sock, sock->ipv6sock};
	const char *socket_str[] = {"IPv4", "IPv6"};

	for(size_t i = 0; i < std::size(sockets); ++i)
	{
		if(sockets[i] >= 0)
		{
#if defined(CONF_FAMILY_WINDOWS)
			if(ioctlsocket(sockets[i], FIONBIO, (unsigned long *)&mode) != NO_ERROR)
			{
				log_error("net", "Setting %s mode for %s socket failed (%s)", socket_str[i], mode_str, net_error_message().c_str());
			}
#else
			if(ioctl(sockets[i], FIONBIO, (unsigned long *)&mode) == -1)
			{
				log_error("net", "Setting %s mode for %s socket failed (%s)", socket_str[i], mode_str, net_error_message().c_str());
			}
#endif
		}
	}

	return 0;
}

int net_set_non_blocking(NETSOCKET sock)
{
	return net_set_blocking_impl(sock, false);
}

int net_set_blocking(NETSOCKET sock)
{
	return net_set_blocking_impl(sock, true);
}

int net_tcp_listen(NETSOCKET sock, int backlog)
{
	int err = -1;
	if(sock->ipv4sock >= 0)
	{
		err = listen(sock->ipv4sock, backlog);
	}
	if(sock->ipv6sock >= 0)
	{
		err = listen(sock->ipv6sock, backlog);
	}
	return err;
}

int net_tcp_accept(NETSOCKET sock, NETSOCKET *new_sock, NETADDR *a)
{
	*new_sock = nullptr;

	if(sock->ipv4sock >= 0)
	{
		sockaddr_storage addr;
		socklen_t sockaddr_len = sizeof(addr);

		int s = accept(sock->ipv4sock, (sockaddr *)&addr, &sockaddr_len);
		if(s != -1)
		{
			sockaddr_to_netaddr((sockaddr *)&addr, sockaddr_len, a);

			*new_sock = (NETSOCKET_INTERNAL *)malloc(sizeof(**new_sock));
			**new_sock = invalid_socket;
			(*new_sock)->type = NETTYPE_IPV4;
			(*new_sock)->ipv4sock = s;
			return s;
		}
	}

	if(sock->ipv6sock >= 0)
	{
		sockaddr_storage addr;
		socklen_t sockaddr_len = sizeof(addr);

		int s = accept(sock->ipv6sock, (sockaddr *)&addr, &sockaddr_len);
		if(s != -1)
		{
			*new_sock = (NETSOCKET_INTERNAL *)malloc(sizeof(**new_sock));
			**new_sock = invalid_socket;
			sockaddr_to_netaddr((sockaddr *)&addr, sockaddr_len, a);
			(*new_sock)->type = NETTYPE_IPV6;
			(*new_sock)->ipv6sock = s;
			return s;
		}
	}

	return -1;
}

int net_tcp_connect(NETSOCKET sock, const NETADDR *a)
{
	if(a->type & NETTYPE_IPV4)
	{
		if(sock->ipv4sock < 0)
			return -2;
		sockaddr_in addr;
		netaddr_to_sockaddr_in(a, &addr);
		return connect(sock->ipv4sock, (sockaddr *)&addr, sizeof(addr));
	}

	if(a->type & NETTYPE_IPV6)
	{
		if(sock->ipv6sock < 0)
			return -2;
		sockaddr_in6 addr;
		netaddr_to_sockaddr_in6(a, &addr);
		return connect(sock->ipv6sock, (sockaddr *)&addr, sizeof(addr));
	}

	return -1;
}

int net_tcp_connect_non_blocking(NETSOCKET sock, NETADDR bindaddr)
{
	net_set_non_blocking(sock);
	int res = net_tcp_connect(sock, &bindaddr);
	net_set_blocking(sock);
	return res;
}

int net_tcp_send(NETSOCKET sock, const void *data, int size)
{
	int bytes = -1;

	if(sock->ipv4sock >= 0)
	{
		bytes = send(sock->ipv4sock, (const char *)data, size, 0);
	}
	if(sock->ipv6sock >= 0)
	{
		bytes = send(sock->ipv6sock, (const char *)data, size, 0);
	}

	return bytes;
}

int net_tcp_recv(NETSOCKET sock, void *data, int maxsize)
{
	int bytes = -1;

	if(sock->ipv4sock >= 0)
	{
		bytes = recv(sock->ipv4sock, (char *)data, maxsize, 0);
	}
	if(sock->ipv6sock >= 0)
	{
		bytes = recv(sock->ipv6sock, (char *)data, maxsize, 0);
	}

	return bytes;
}

void net_tcp_close(NETSOCKET sock)
{
	priv_net_close_all_sockets(sock);
}

int net_errno()
{
#if defined(CONF_FAMILY_WINDOWS)
	return WSAGetLastError();
#else
	return errno;
#endif
}

std::string net_error_message()
{
	const int error = net_errno();
#if defined(CONF_FAMILY_WINDOWS)
	const std::string message = windows_format_system_message(error);
	return std::to_string(error) + " '" + message + "'";
#else
	return std::to_string(error) + " '" + strerror(error) + "'";
#endif
}

int net_would_block()
{
#if defined(CONF_FAMILY_WINDOWS)
	return net_errno() == WSAEWOULDBLOCK;
#else
	return net_errno() == EWOULDBLOCK;
#endif
}

void net_init()
{
#if defined(CONF_FAMILY_WINDOWS)
	WSADATA wsa_data;
	dbg_assert(WSAStartup(MAKEWORD(1, 1), &wsa_data) == 0, "WSAStartup failure");
#endif
#if defined(CONF_WEBSOCKETS)
	websocket_init();
#endif
}

#if defined(CONF_FAMILY_UNIX)
UNIXSOCKET net_unix_create_unnamed()
{
	return socket(AF_UNIX, SOCK_DGRAM, 0);
}

int net_unix_send(UNIXSOCKET sock, UNIXSOCKETADDR *addr, void *data, int size)
{
	return sendto(sock, data, size, 0, (sockaddr *)addr, sizeof(*addr));
}

void net_unix_set_addr(UNIXSOCKETADDR *addr, const char *path)
{
	mem_zero(addr, sizeof(*addr));
	addr->sun_family = AF_UNIX;
	str_copy(addr->sun_path, path);
}

void net_unix_close(UNIXSOCKET sock)
{
	close(sock);
}
#endif

#if defined(CONF_FAMILY_WINDOWS)
static inline time_t filetime_to_unixtime(LPFILETIME filetime)
{
	time_t t;
	ULARGE_INTEGER li;
	li.LowPart = filetime->dwLowDateTime;
	li.HighPart = filetime->dwHighDateTime;

	li.QuadPart /= 10000000; // 100ns to 1s
	li.QuadPart -= 11644473600LL; // Windows epoch is in the past

	t = li.QuadPart;
	return t == (time_t)li.QuadPart ? t : (time_t)-1;
}
#endif

void fs_listdir(const char *dir, FS_LISTDIR_CALLBACK cb, int type, void *user)
{
#if defined(CONF_FAMILY_WINDOWS)
	char buffer[IO_MAX_PATH_LENGTH];
	str_format(buffer, sizeof(buffer), "%s/*", dir);
	const std::wstring wide_buffer = windows_utf8_to_wide(buffer);

	WIN32_FIND_DATAW finddata;
	HANDLE handle = FindFirstFileW(wide_buffer.c_str(), &finddata);
	if(handle == INVALID_HANDLE_VALUE)
		return;

	do
	{
		const std::optional<std::string> current_entry = windows_wide_to_utf8(finddata.cFileName);
		if(!current_entry.has_value())
		{
			log_error("filesystem", "ERROR: file/folder name containing invalid UTF-16 found in folder '%s'", dir);
			continue;
		}
		if(cb(current_entry.value().c_str(), (finddata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0, type, user))
			break;
	} while(FindNextFileW(handle, &finddata));

	FindClose(handle);
#else
	DIR *dir_handle = opendir(dir);
	if(dir_handle == nullptr)
		return;

	char buffer[IO_MAX_PATH_LENGTH];
	str_format(buffer, sizeof(buffer), "%s/", dir);
	size_t length = str_length(buffer);
	while(true)
	{
		struct dirent *entry = readdir(dir_handle);
		if(entry == nullptr)
			break;
		if(!str_utf8_check(entry->d_name))
		{
			log_error("filesystem", "ERROR: file/folder name containing invalid UTF-8 found in folder '%s'", dir);
			continue;
		}
		str_copy(buffer + length, entry->d_name, sizeof(buffer) - length);
		if(cb(entry->d_name, fs_is_dir(buffer), type, user))
			break;
	}

	closedir(dir_handle);
#endif
}

void fs_listdir_fileinfo(const char *dir, FS_LISTDIR_CALLBACK_FILEINFO cb, int type, void *user)
{
#if defined(CONF_FAMILY_WINDOWS)
	char buffer[IO_MAX_PATH_LENGTH];
	str_format(buffer, sizeof(buffer), "%s/*", dir);
	const std::wstring wide_buffer = windows_utf8_to_wide(buffer);

	WIN32_FIND_DATAW finddata;
	HANDLE handle = FindFirstFileW(wide_buffer.c_str(), &finddata);
	if(handle == INVALID_HANDLE_VALUE)
		return;

	do
	{
		const std::optional<std::string> current_entry = windows_wide_to_utf8(finddata.cFileName);
		if(!current_entry.has_value())
		{
			log_error("filesystem", "ERROR: file/folder name containing invalid UTF-16 found in folder '%s'", dir);
			continue;
		}

		CFsFileInfo info;
		info.m_pName = current_entry.value().c_str();
		info.m_TimeCreated = filetime_to_unixtime(&finddata.ftCreationTime);
		info.m_TimeModified = filetime_to_unixtime(&finddata.ftLastWriteTime);

		if(cb(&info, (finddata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0, type, user))
			break;
	} while(FindNextFileW(handle, &finddata));

	FindClose(handle);
#else
	DIR *dir_handle = opendir(dir);
	if(dir_handle == nullptr)
		return;

	char buffer[IO_MAX_PATH_LENGTH];
	str_format(buffer, sizeof(buffer), "%s/", dir);
	size_t length = str_length(buffer);

	while(true)
	{
		struct dirent *entry = readdir(dir_handle);
		if(entry == nullptr)
			break;
		if(!str_utf8_check(entry->d_name))
		{
			log_error("filesystem", "ERROR: file/folder name containing invalid UTF-8 found in folder '%s'", dir);
			continue;
		}
		str_copy(buffer + length, entry->d_name, sizeof(buffer) - length);
		time_t created = -1, modified = -1;
		fs_file_time(buffer, &created, &modified);

		CFsFileInfo info;
		info.m_pName = entry->d_name;
		info.m_TimeCreated = created;
		info.m_TimeModified = modified;

		if(cb(&info, fs_is_dir(buffer), type, user))
			break;
	}

	closedir(dir_handle);
#endif
}

int fs_storage_path(const char *appname, char *path, int max)
{
#if defined(CONF_FAMILY_WINDOWS)
	WCHAR *wide_home = nullptr;
	if(SHGetKnownFolderPath(FOLDERID_RoamingAppData, 0, /* current user */ nullptr, &wide_home) != S_OK)
	{
		log_error("filesystem", "ERROR: could not determine location of Roaming/AppData folder");
		CoTaskMemFree(wide_home);
		path[0] = '\0';
		return -1;
	}
	const std::optional<std::string> home = windows_wide_to_utf8(wide_home);
	CoTaskMemFree(wide_home);
	if(!home.has_value())
	{
		log_error("filesystem", "ERROR: path of Roaming/AppData folder contains invalid UTF-16");
		path[0] = '\0';
		return -1;
	}
	str_copy(path, home.value().c_str(), max);
	fs_normalize_path(path);
	str_append(path, "/", max);
	str_append(path, appname, max);
	return 0;
#else
	char *home = getenv("HOME");
	if(!home)
	{
		path[0] = '\0';
		return -1;
	}

	if(!str_utf8_check(home))
	{
		log_error("filesystem", "ERROR: the HOME environment variable contains invalid UTF-8");
		path[0] = '\0';
		return -1;
	}

#if defined(CONF_PLATFORM_HAIKU)
	str_format(path, max, "%s/config/settings/%s", home, appname);
#elif defined(CONF_PLATFORM_MACOS)
	str_format(path, max, "%s/Library/Application Support/%s", home, appname);
#else
	if(str_comp(appname, "Teeworlds") == 0)
	{
		// fallback for old directory for Teeworlds compatibility
		str_format(path, max, "%s/.%s", home, appname);
	}
	else
	{
		char *data_home = getenv("XDG_DATA_HOME");
		if(data_home)
		{
			if(!str_utf8_check(data_home))
			{
				log_error("filesystem", "ERROR: the XDG_DATA_HOME environment variable contains invalid UTF-8");
				path[0] = '\0';
				return -1;
			}
			str_format(path, max, "%s/%s", data_home, appname);
		}
		else
			str_format(path, max, "%s/.local/share/%s", home, appname);
	}
	for(int i = str_length(path) - str_length(appname); path[i]; i++)
		path[i] = tolower((unsigned char)path[i]);
#endif

	return 0;
#endif
}

int fs_makedir_rec_for(const char *path)
{
	char buffer[IO_MAX_PATH_LENGTH];
	str_copy(buffer, path);
	for(int index = 1; buffer[index] != '\0'; ++index)
	{
		// Do not try to create folder for drive letters on Windows,
		// as this is not necessary and may fail for system drives.
		if((buffer[index] == '/' || buffer[index] == '\\') && buffer[index + 1] != '\0' && buffer[index - 1] != ':')
		{
			buffer[index] = '\0';
			if(fs_makedir(buffer) < 0)
			{
				return -1;
			}
			buffer[index] = '/';
		}
	}
	return 0;
}

int fs_is_file(const char *path)
{
#if defined(CONF_FAMILY_WINDOWS)
	const std::wstring wide_path = windows_utf8_to_wide(path);
	DWORD attributes = GetFileAttributesW(wide_path.c_str());
	return attributes != INVALID_FILE_ATTRIBUTES && !(attributes & FILE_ATTRIBUTE_DIRECTORY) ? 1 : 0;
#else
	struct stat sb;
	if(stat(path, &sb) == -1)
		return 0;
	return S_ISREG(sb.st_mode) ? 1 : 0;
#endif
}

int fs_is_dir(const char *path)
{
#if defined(CONF_FAMILY_WINDOWS)
	const std::wstring wide_path = windows_utf8_to_wide(path);
	DWORD attributes = GetFileAttributesW(wide_path.c_str());
	return attributes != INVALID_FILE_ATTRIBUTES && (attributes & FILE_ATTRIBUTE_DIRECTORY) ? 1 : 0;
#else
	struct stat sb;
	if(stat(path, &sb) == -1)
		return 0;
	return S_ISDIR(sb.st_mode) ? 1 : 0;
#endif
}

int fs_is_relative_path(const char *path)
{
#if defined(CONF_FAMILY_WINDOWS)
	const std::wstring wide_path = windows_utf8_to_wide(path);
	return PathIsRelativeW(wide_path.c_str()) ? 1 : 0;
#else
	return path[0] == '/' ? 0 : 1; // yes, it's that simple
#endif
}

int fs_chdir(const char *path)
{
#if defined(CONF_FAMILY_WINDOWS)
	const std::wstring wide_path = windows_utf8_to_wide(path);
	return SetCurrentDirectoryW(wide_path.c_str()) != 0 ? 0 : 1;
#else
	return chdir(path) ? 1 : 0;
#endif
}

char *fs_getcwd(char *buffer, int buffer_size)
{
#if defined(CONF_FAMILY_WINDOWS)
	const DWORD size_needed = GetCurrentDirectoryW(0, nullptr);
	std::wstring wide_current_dir(size_needed, L'0');
	dbg_assert(GetCurrentDirectoryW(size_needed, wide_current_dir.data()) == size_needed - 1, "GetCurrentDirectoryW failure");
	const std::optional<std::string> current_dir = windows_wide_to_utf8(wide_current_dir.c_str());
	if(!current_dir.has_value())
	{
		buffer[0] = '\0';
		return nullptr;
	}
	str_copy(buffer, current_dir.value().c_str(), buffer_size);
	fs_normalize_path(buffer);
	return buffer;
#else
	char *result = getcwd(buffer, buffer_size);
	if(result == nullptr || !str_utf8_check(result))
	{
		buffer[0] = '\0';
		return nullptr;
	}
	return result;
#endif
}

const char *fs_filename(const char *path)
{
	for(const char *filename = path + str_length(path); filename >= path; --filename)
	{
		if(filename[0] == '/' || filename[0] == '\\')
			return filename + 1;
	}
	return path;
}

void fs_split_file_extension(const char *filename, char *name, size_t name_size, char *extension, size_t extension_size)
{
	dbg_assert(name != nullptr || extension != nullptr, "name or extension parameter required");
	dbg_assert(name == nullptr || name_size > 0, "name_size invalid");
	dbg_assert(extension == nullptr || extension_size > 0, "extension_size invalid");

	const char *last_dot = str_rchr(filename, '.');
	if(last_dot == nullptr || last_dot == filename)
	{
		if(extension != nullptr)
			extension[0] = '\0';
		if(name != nullptr)
			str_copy(name, filename, name_size);
	}
	else
	{
		if(extension != nullptr)
			str_copy(extension, last_dot + 1, extension_size);
		if(name != nullptr)
			str_truncate(name, name_size, filename, last_dot - filename);
	}
}

void fs_normalize_path(char *path)
{
	for(int i = 0; path[i] != '\0';)
	{
		if(path[i] == '\\')
		{
			path[i] = '/';
		}
		if(i > 0 && path[i] == '/' && path[i + 1] == '\0')
		{
			path[i] = '\0';
			--i;
		}
		else
		{
			++i;
		}
	}
}

int fs_parent_dir(char *path)
{
	char *parent = nullptr;
	for(; *path; ++path)
	{
		if(*path == '/' || *path == '\\')
			parent = path;
	}

	if(parent)
	{
		*parent = 0;
		return 0;
	}
	return 1;
}

int fs_remove(const char *filename)
{
#if defined(CONF_FAMILY_WINDOWS)
	if(fs_is_dir(filename))
	{
		// Not great, but otherwise using this function on a folder would only rename the folder but fail to delete it.
		return 1;
	}
	const std::wstring wide_filename = windows_utf8_to_wide(filename);

	unsigned random_num;
	secure_random_fill(&random_num, sizeof(random_num));
	std::wstring wide_filename_temp;
	do
	{
		char suffix[64];
		str_format(suffix, sizeof(suffix), ".%08X.toberemoved", random_num);
		wide_filename_temp = wide_filename + windows_utf8_to_wide(suffix);
		++random_num;
	} while(GetFileAttributesW(wide_filename_temp.c_str()) != INVALID_FILE_ATTRIBUTES);

	// The DeleteFileW function only marks the file for deletion but the deletion may not take effect immediately, which can
	// cause subsequent operations using this filename to fail until all handles are closed. The MoveFileExW function with the
	// MOVEFILE_WRITE_THROUGH flag is guaranteed to wait for the file to be moved on disk, so we first rename the file to be
	// deleted to a random temporary name and then mark that for deletion, to ensure that the filename is usable immediately.
	if(MoveFileExW(wide_filename.c_str(), wide_filename_temp.c_str(), MOVEFILE_WRITE_THROUGH) == 0)
	{
		const DWORD error = GetLastError();
		if(error == ERROR_FILE_NOT_FOUND)
		{
			return 0; // Success: Renaming failed because the original file did not exist.
		}
		const std::string filename_temp = windows_wide_to_utf8(wide_filename_temp.c_str()).value_or("(invalid filename)");
		log_error("filesystem", "Failed to rename file '%s' to '%s' for removal (%ld '%s')", filename, filename_temp.c_str(), error, windows_format_system_message(error).c_str());
		return 1;
	}
	if(DeleteFileW(wide_filename_temp.c_str()) != 0)
	{
		return 0; // Success: Marked the renamed file for deletion successfully.
	}
	const DWORD error = GetLastError();
	if(error == ERROR_FILE_NOT_FOUND)
	{
		return 0; // Success: Another process deleted the renamed file we were about to delete?!
	}
	const std::string filename_temp = windows_wide_to_utf8(wide_filename_temp.c_str()).value_or("(invalid filename)");
	log_error("filesystem", "Failed to remove file '%s' (%ld '%s')", filename_temp.c_str(), error, windows_format_system_message(error).c_str());
	// Success: While the temporary could not be deleted, this is also considered success because the original file does not exist anymore.
	//          Callers of this function expect that the original file does not exist anymore if and only if the function succeeded.
	return 0;
#else
	if(unlink(filename) == 0 || errno == ENOENT)
	{
		return 0;
	}
	log_error("filesystem", "Failed to remove file '%s' (%d '%s')", filename, errno, strerror(errno));
	return 1;
#endif
}

int fs_rename(const char *oldname, const char *newname)
{
#if defined(CONF_FAMILY_WINDOWS)
	const std::wstring wide_oldname = windows_utf8_to_wide(oldname);
	const std::wstring wide_newname = windows_utf8_to_wide(newname);
	if(MoveFileExW(wide_oldname.c_str(), wide_newname.c_str(), MOVEFILE_REPLACE_EXISTING | MOVEFILE_COPY_ALLOWED | MOVEFILE_WRITE_THROUGH) != 0)
	{
		return 0;
	}
	const DWORD error = GetLastError();
	log_error("filesystem", "Failed to rename file '%s' to '%s' (%ld '%s')", oldname, newname, error, windows_format_system_message(error).c_str());
	return 1;
#else
	if(rename(oldname, newname) == 0)
	{
		return 0;
	}
	log_error("filesystem", "Failed to rename file '%s' to '%s' (%d '%s')", oldname, newname, errno, strerror(errno));
	return 1;
#endif
}

int fs_file_time(const char *name, time_t *created, time_t *modified)
{
#if defined(CONF_FAMILY_WINDOWS)
	WIN32_FIND_DATAW finddata;
	const std::wstring wide_name = windows_utf8_to_wide(name);
	HANDLE handle = FindFirstFileW(wide_name.c_str(), &finddata);
	if(handle == INVALID_HANDLE_VALUE)
		return 1;

	*created = filetime_to_unixtime(&finddata.ftCreationTime);
	*modified = filetime_to_unixtime(&finddata.ftLastWriteTime);
	FindClose(handle);
#elif defined(CONF_FAMILY_UNIX)
	struct stat sb;
	if(stat(name, &sb))
		return 1;

	*created = sb.st_ctime;
	*modified = sb.st_mtime;
#else
#error not implemented
#endif

	return 0;
}

void swap_endian(void *data, unsigned elem_size, unsigned num)
{
	char *src = (char *)data;
	char *dst = src + (elem_size - 1);

	while(num)
	{
		unsigned n = elem_size >> 1;
		char tmp;
		while(n)
		{
			tmp = *src;
			*src = *dst;
			*dst = tmp;

			src++;
			dst--;
			n--;
		}

		src = src + (elem_size >> 1);
		dst = src + (elem_size - 1);
		num--;
	}
}

int net_socket_read_wait(NETSOCKET sock, std::chrono::nanoseconds nanoseconds)
{
	const int64_t microseconds = std::chrono::duration_cast<std::chrono::microseconds>(nanoseconds).count();
	dbg_assert(microseconds >= 0, "Negative wait duration %" PRId64 " not allowed", microseconds);

	fd_set readfds;
	FD_ZERO(&readfds);

	int maxfd = -1;
	if(sock->ipv4sock >= 0)
	{
		FD_SET(sock->ipv4sock, &readfds);
		maxfd = sock->ipv4sock;
	}
	if(sock->ipv6sock >= 0)
	{
		FD_SET(sock->ipv6sock, &readfds);
		maxfd = std::max(maxfd, sock->ipv6sock);
	}
#if defined(CONF_WEBSOCKETS)
	if(sock->web_ipv4sock >= 0)
	{
		maxfd = std::max(maxfd, websocket_fd_set(sock->web_ipv4sock, &readfds));
	}
	if(sock->web_ipv6sock >= 0)
	{
		maxfd = std::max(maxfd, websocket_fd_set(sock->web_ipv6sock, &readfds));
	}
#endif
	if(maxfd < 0)
	{
		return 0;
	}

	struct timeval tv;
	tv.tv_sec = microseconds / 1000000;
	tv.tv_usec = microseconds % 1000000;
	// don't care about writefds and exceptfds
	select(maxfd + 1, &readfds, nullptr, nullptr, &tv);

	if(sock->ipv4sock >= 0 && FD_ISSET(sock->ipv4sock, &readfds))
	{
		return 1;
	}
	if(sock->ipv6sock >= 0 && FD_ISSET(sock->ipv6sock, &readfds))
	{
		return 1;
	}
#if defined(CONF_WEBSOCKETS)
	if(sock->web_ipv4sock >= 0 && websocket_fd_get(sock->web_ipv4sock, &readfds))
	{
		return 1;
	}
	if(sock->web_ipv6sock >= 0 && websocket_fd_get(sock->web_ipv6sock, &readfds))
	{
		return 1;
	}
#endif
	return 0;
}

int str_format_v(char *buffer, int buffer_size, const char *format, va_list args)
{
#if defined(CONF_FAMILY_WINDOWS)
	_vsprintf_p(buffer, buffer_size, format, args);
	buffer[buffer_size - 1] = 0; /* assure null termination */
#else
	vsnprintf(buffer, buffer_size, format, args);
	/* null termination is assured by definition of vsnprintf */
#endif
	return str_utf8_fix_truncation(buffer);
}

#if !defined(CONF_DEBUG)
int str_format_int(char *buffer, size_t buffer_size, int value)
{
	buffer[0] = '\0'; // Fix false positive clang-analyzer-core.UndefinedBinaryOperatorResult when using result
	auto result = std::to_chars(buffer, buffer + buffer_size - 1, value);
	result.ptr[0] = '\0';
	return result.ptr - buffer;
}
#endif

#undef str_format
int str_format(char *buffer, int buffer_size, const char *format, ...)
{
	va_list args;
	va_start(args, format);
	int length = str_format_v(buffer, buffer_size, format, args);
	va_end(args);
	return length;
}
#if !defined(CONF_DEBUG)
#define str_format str_format_opt
#endif

static int min3(int a, int b, int c)
{
	int min = a;
	if(b < min)
		min = b;
	if(c < min)
		min = c;
	return min;
}

int str_utf8_dist(const char *a, const char *b)
{
	int buf_len = 2 * (str_length(a) + 1 + str_length(b) + 1);
	int *buf = (int *)calloc(buf_len, sizeof(*buf));
	int result = str_utf8_dist_buffer(a, b, buf, buf_len);
	free(buf);
	return result;
}

static int str_to_utf32_unchecked(const char *str, int **out)
{
	int out_len = 0;
	while((**out = str_utf8_decode(&str)))
	{
		(*out)++;
		out_len++;
	}
	return out_len;
}

int str_utf32_dist_buffer(const int *a, int a_len, const int *b, int b_len, int *buf, int buf_len)
{
	int i, j;
	dbg_assert(buf_len >= (a_len + 1) + (b_len + 1), "buffer too small");
	if(a_len > b_len)
	{
		int tmp1 = a_len;
		const int *tmp2 = a;

		a_len = b_len;
		a = b;

		b_len = tmp1;
		b = tmp2;
	}
#define B(i, j) buf[((j) & 1) * (a_len + 1) + (i)]
	for(i = 0; i <= a_len; i++)
	{
		B(i, 0) = i;
	}
	for(j = 1; j <= b_len; j++)
	{
		B(0, j) = j;
		for(i = 1; i <= a_len; i++)
		{
			int subst = (a[i - 1] != b[j - 1]);
			B(i, j) = min3(
				B(i - 1, j) + 1,
				B(i, j - 1) + 1,
				B(i - 1, j - 1) + subst);
		}
	}
	return B(a_len, b_len);
#undef B
}

int str_utf8_dist_buffer(const char *a_utf8, const char *b_utf8, int *buf, int buf_len)
{
	int a_utf8_len = str_length(a_utf8);
	int b_utf8_len = str_length(b_utf8);
	int *a, *b; // UTF-32
	int a_len, b_len; // UTF-32 length
	dbg_assert(buf_len >= 2 * (a_utf8_len + 1 + b_utf8_len + 1), "buffer too small");
	if(a_utf8_len > b_utf8_len)
	{
		const char *tmp2 = a_utf8;
		a_utf8 = b_utf8;
		b_utf8 = tmp2;
	}
	a = buf;
	a_len = str_to_utf32_unchecked(a_utf8, &buf);
	b = buf;
	b_len = str_to_utf32_unchecked(b_utf8, &buf);
	return str_utf32_dist_buffer(a, a_len, b, b_len, buf, buf_len - b_len - a_len);
}

void net_stats(NETSTATS *stats_inout)
{
	*stats_inout = network_stats;
}

static_assert(sizeof(unsigned) == 4, "unsigned must be 4 bytes in size");
static_assert(sizeof(unsigned) == sizeof(int), "unsigned and int must have the same size");

unsigned bytes_be_to_uint(const unsigned char *bytes)
{
	return ((bytes[0] & 0xffu) << 24u) | ((bytes[1] & 0xffu) << 16u) | ((bytes[2] & 0xffu) << 8u) | (bytes[3] & 0xffu);
}

void uint_to_bytes_be(unsigned char *bytes, unsigned value)
{
	bytes[0] = (value >> 24u) & 0xffu;
	bytes[1] = (value >> 16u) & 0xffu;
	bytes[2] = (value >> 8u) & 0xffu;
	bytes[3] = value & 0xffu;
}

int pid()
{
#if defined(CONF_FAMILY_WINDOWS)
	return _getpid();
#else
	return getpid();
#endif
}

void cmdline_fix(int *argc, const char ***argv)
{
#if defined(CONF_FAMILY_WINDOWS)
	int wide_argc = 0;
	WCHAR **wide_argv = CommandLineToArgvW(GetCommandLineW(), &wide_argc);
	dbg_assert(wide_argv != NULL, "CommandLineToArgvW failure");
	dbg_assert(wide_argc > 0, "Invalid argc value");

	int total_size = 0;

	for(int i = 0; i < wide_argc; i++)
	{
		int size = WideCharToMultiByte(CP_UTF8, 0, wide_argv[i], -1, nullptr, 0, nullptr, nullptr);
		dbg_assert(size != 0, "WideCharToMultiByte failure");
		total_size += size;
	}

	char **new_argv = (char **)malloc((wide_argc + 1) * sizeof(*new_argv));
	new_argv[0] = (char *)malloc(total_size);
	mem_zero(new_argv[0], total_size);

	int remaining_size = total_size;
	for(int i = 0; i < wide_argc; i++)
	{
		int size = WideCharToMultiByte(CP_UTF8, 0, wide_argv[i], -1, new_argv[i], remaining_size, nullptr, nullptr);
		dbg_assert(size != 0, "WideCharToMultiByte failure");

		remaining_size -= size;
		new_argv[i + 1] = new_argv[i] + size;
	}

	LocalFree(wide_argv);
	new_argv[wide_argc] = nullptr;
	*argc = wide_argc;
	*argv = (const char **)new_argv;
#endif
}

void cmdline_free(int argc, const char **argv)
{
#if defined(CONF_FAMILY_WINDOWS)
	free((void *)*argv);
	free((char **)argv);
#endif
}

#if !defined(CONF_PLATFORM_ANDROID)
PROCESS shell_execute(const char *file, EShellExecuteWindowState window_state, const char **arguments, const size_t num_arguments)
{
	dbg_assert((arguments == nullptr) == (num_arguments == 0), "Invalid number of arguments");
#if defined(CONF_FAMILY_WINDOWS)
	dbg_assert(str_endswith_nocase(file, ".bat") == nullptr && str_endswith_nocase(file, ".cmd") == nullptr, "Running batch files not allowed");
	dbg_assert(str_endswith(file, ".exe") != nullptr || num_arguments == 0, "Arguments only allowed with .exe files");

	const std::wstring wide_file = windows_utf8_to_wide(file);
	std::wstring wide_arguments = windows_args_to_wide(arguments, num_arguments);

	SHELLEXECUTEINFOW info;
	mem_zero(&info, sizeof(SHELLEXECUTEINFOW));
	info.cbSize = sizeof(SHELLEXECUTEINFOW);
	info.lpVerb = L"open";
	info.lpFile = wide_file.c_str();
	info.lpParameters = num_arguments > 0 ? wide_arguments.c_str() : nullptr;
	switch(window_state)
	{
	case EShellExecuteWindowState::FOREGROUND:
		info.nShow = SW_SHOW;
		break;
	case EShellExecuteWindowState::BACKGROUND:
		info.nShow = SW_SHOWMINNOACTIVE;
		break;
	default:
		dbg_assert_failed("Invalid window_state: %d", static_cast<int>(window_state));
	}
	info.fMask = SEE_MASK_NOCLOSEPROCESS;
	// Save and restore the FPU control word because ShellExecute might change it
	fenv_t floating_point_environment;
	int fegetenv_result = fegetenv(&floating_point_environment);
	ShellExecuteExW(&info);
	if(fegetenv_result == 0)
		fesetenv(&floating_point_environment);
	return info.hProcess;
#elif defined(CONF_FAMILY_UNIX)
	char **argv = (char **)malloc((num_arguments + 2) * sizeof(*argv));
	pid_t pid;
	argv[0] = (char *)file;
	for(size_t i = 0; i < num_arguments; ++i)
	{
		argv[i + 1] = (char *)arguments[i];
	}
	argv[num_arguments + 1] = NULL;
	pid = fork();
	if(pid == -1)
	{
		free(argv);
		return 0;
	}
	if(pid == 0)
	{
		execvp(file, argv);
		_exit(1);
	}
	free(argv);
	return pid;
#endif
}

int kill_process(PROCESS process)
{
#if defined(CONF_FAMILY_WINDOWS)
	BOOL success = TerminateProcess(process, 0);
	BOOL is_alive = is_process_alive(process);
	if(success || !is_alive)
	{
		CloseHandle(process);
		return true;
	}
	return false;
#elif defined(CONF_FAMILY_UNIX)
	if(!is_process_alive(process))
		return true;
	int status;
	kill(process, SIGTERM);
	return waitpid(process, &status, 0) != -1;
#endif
}

bool is_process_alive(PROCESS process)
{
	if(process == INVALID_PROCESS)
		return false;
#if defined(CONF_FAMILY_WINDOWS)
	DWORD exit_code;
	GetExitCodeProcess(process, &exit_code);
	return exit_code == STILL_ACTIVE;
#else
	return waitpid(process, nullptr, WNOHANG) == 0;
#endif
}

int open_link(const char *link)
{
#if defined(CONF_FAMILY_WINDOWS)
	const std::wstring wide_link = windows_utf8_to_wide(link);

	SHELLEXECUTEINFOW info;
	mem_zero(&info, sizeof(SHELLEXECUTEINFOW));
	info.cbSize = sizeof(SHELLEXECUTEINFOW);
	info.lpVerb = nullptr; // NULL to use the default verb, as "open" may not be available
	info.lpFile = wide_link.c_str();
	info.nShow = SW_SHOWNORMAL;
	// The SEE_MASK_NOASYNC flag ensures that the ShellExecuteEx function
	// finishes its DDE conversation before it returns, so it's not necessary
	// to pump messages in the calling thread.
	// The SEE_MASK_FLAG_NO_UI flag suppresses error messages that would pop up
	// when the link cannot be opened, e.g. when a folder does not exist.
	// The SEE_MASK_ASYNCOK flag is not used. It would allow the call to
	// ShellExecuteEx to return earlier, but it also prevents us from doing
	// our own error handling, as the function would always return TRUE.
	info.fMask = SEE_MASK_NOASYNC | SEE_MASK_FLAG_NO_UI;
	// Save and restore the FPU control word because ShellExecute might change it
	fenv_t floating_point_environment;
	int fegetenv_result = fegetenv(&floating_point_environment);
	BOOL success = ShellExecuteExW(&info);
	if(fegetenv_result == 0)
		fesetenv(&floating_point_environment);
	return success;
#elif defined(CONF_PLATFORM_LINUX)
	const int pid = fork();
	if(pid == 0)
		execlp("xdg-open", "xdg-open", link, nullptr);
	return pid > 0;
#elif defined(CONF_FAMILY_UNIX)
	const int pid = fork();
	if(pid == 0)
		execlp("open", "open", link, nullptr);
	return pid > 0;
#endif
}

int open_file(const char *path)
{
#if defined(CONF_PLATFORM_MACOS)
	return open_link(path);
#else
	// Create a file link so the path can contain forward and
	// backward slashes. But the file link must be absolute.
	char buf[512];
	char workingDir[IO_MAX_PATH_LENGTH];
	if(fs_is_relative_path(path))
	{
		if(!fs_getcwd(workingDir, sizeof(workingDir)))
			return 0;
		str_append(workingDir, "/");
	}
	else
		workingDir[0] = '\0';
	str_format(buf, sizeof(buf), "file://%s%s", workingDir, path);
	return open_link(buf);
#endif
}
#endif // !defined(CONF_PLATFORM_ANDROID)

struct SECURE_RANDOM_DATA
{
	std::once_flag initialized_once_flag;
#if defined(CONF_FAMILY_WINDOWS)
	HCRYPTPROV provider;
#else
	IOHANDLE urandom;
#endif
};

static struct SECURE_RANDOM_DATA secure_random_data = {};

static void ensure_secure_random_init()
{
	std::call_once(secure_random_data.initialized_once_flag, []() {
#if defined(CONF_FAMILY_WINDOWS)
		if(!CryptAcquireContext(&secure_random_data.provider, nullptr, nullptr, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
		{
			const DWORD LastError = GetLastError();
			dbg_assert_failed("Failed to initialize secure random: CryptAcquireContext failure (%ld '%s')", LastError, windows_format_system_message(LastError).c_str());
		}
#else
		secure_random_data.urandom = io_open("/dev/urandom", IOFLAG_READ);
		dbg_assert(secure_random_data.urandom != nullptr, "Failed to initialize secure random: failed to open /dev/urandom");
#endif
	});
}

void generate_password(char *buffer, unsigned length, const unsigned short *random, unsigned random_length)
{
	static const char VALUES[] = "ABCDEFGHKLMNPRSTUVWXYZabcdefghjkmnopqt23456789";
	static const size_t NUM_VALUES = sizeof(VALUES) - 1; // Disregard the '\0'.
	unsigned i;
	dbg_assert(length >= random_length * 2 + 1, "too small buffer");
	dbg_assert(NUM_VALUES * NUM_VALUES >= 2048, "need at least 2048 possibilities for 2-character sequences");

	buffer[random_length * 2] = 0;

	for(i = 0; i < random_length; i++)
	{
		unsigned short random_number = random[i] % 2048;
		buffer[2 * i + 0] = VALUES[random_number / NUM_VALUES];
		buffer[2 * i + 1] = VALUES[random_number % NUM_VALUES];
	}
}

#define MAX_PASSWORD_LENGTH 128

void secure_random_password(char *buffer, unsigned length, unsigned pw_length)
{
	unsigned short random[MAX_PASSWORD_LENGTH / 2];
	// With 6 characters, we get a password entropy of log(2048) * 6/2 = 33bit.
	dbg_assert(length >= pw_length + 1, "too small buffer");
	dbg_assert(pw_length >= 6, "too small password length");
	dbg_assert(pw_length % 2 == 0, "need an even password length");
	dbg_assert(pw_length <= MAX_PASSWORD_LENGTH, "too large password length");

	secure_random_fill(random, pw_length);

	generate_password(buffer, length, random, pw_length / 2);
}

#undef MAX_PASSWORD_LENGTH

void secure_random_fill(void *bytes, unsigned length)
{
	ensure_secure_random_init();
#if defined(CONF_FAMILY_WINDOWS)
	if(!CryptGenRandom(secure_random_data.provider, length, (unsigned char *)bytes))
	{
		const DWORD LastError = GetLastError();
		dbg_assert_failed("CryptGenRandom failure (%ld '%s')", LastError, windows_format_system_message(LastError).c_str());
	}
#else
	dbg_assert(length == io_read(secure_random_data.urandom, bytes, length), "io_read returned with a short read");
#endif
}

// From https://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2.
static unsigned int find_next_power_of_two_minus_one(unsigned int n)
{
	n--;
	n |= n >> 1;
	n |= n >> 2;
	n |= n >> 4;
	n |= n >> 4;
	n |= n >> 16;
	return n;
}

int secure_rand_below(int below)
{
	unsigned int mask = find_next_power_of_two_minus_one(below);
	dbg_assert(below > 0, "below must be positive");
	while(true)
	{
		unsigned int n;
		secure_random_fill(&n, sizeof(n));
		n &= mask;
		if((int)n < below)
		{
			return n;
		}
	}
}

bool os_version_str(char *version, size_t length)
{
#if defined(CONF_FAMILY_WINDOWS)
	const WCHAR *module_path = L"kernel32.dll";
	DWORD handle;
	DWORD size = GetFileVersionInfoSizeW(module_path, &handle);
	if(!size)
	{
		return false;
	}
	void *data = malloc(size);
	if(!GetFileVersionInfoW(module_path, handle, size, data))
	{
		free(data);
		return false;
	}
	VS_FIXEDFILEINFO *fileinfo;
	UINT unused;
	if(!VerQueryValueW(data, L"\\", (void **)&fileinfo, &unused))
	{
		free(data);
		return false;
	}
	str_format(version, length, "Windows %hu.%hu.%hu.%hu",
		HIWORD(fileinfo->dwProductVersionMS),
		LOWORD(fileinfo->dwProductVersionMS),
		HIWORD(fileinfo->dwProductVersionLS),
		LOWORD(fileinfo->dwProductVersionLS));
	free(data);
	return true;
#else
	struct utsname u;
	if(uname(&u))
	{
		return false;
	}
	char extra[128];
	extra[0] = 0;

	do
	{
		IOHANDLE os_release = io_open("/etc/os-release", IOFLAG_READ);
		char buf[4096];
		int read;
		int offset;
		char *newline;
		if(!os_release)
		{
			break;
		}
		read = io_read(os_release, buf, sizeof(buf) - 1);
		io_close(os_release);
		buf[read] = 0;
		if(str_startswith(buf, "PRETTY_NAME="))
		{
			offset = 0;
		}
		else
		{
			const char *found = str_find(buf, "\nPRETTY_NAME=");
			if(!found)
			{
				break;
			}
			offset = found - buf + 1;
		}
		newline = (char *)str_find(buf + offset, "\n");
		if(newline)
		{
			*newline = 0;
		}
		str_format(extra, sizeof(extra), "; %s", buf + offset + 12);
	} while(false);

	str_format(version, length, "%s %s (%s, %s)%s", u.sysname, u.release, u.machine, u.version, extra);
	return true;
#endif
}

void os_locale_str(char *locale, size_t length)
{
#if defined(CONF_FAMILY_WINDOWS)
	wchar_t wide_buffer[LOCALE_NAME_MAX_LENGTH];
	dbg_assert(GetUserDefaultLocaleName(wide_buffer, std::size(wide_buffer)) > 0, "GetUserDefaultLocaleName failure");

	const std::optional<std::string> buffer = windows_wide_to_utf8(wide_buffer);
	dbg_assert(buffer.has_value(), "GetUserDefaultLocaleName returned invalid UTF-16");
	str_copy(locale, buffer.value().c_str(), length);
#elif defined(CONF_PLATFORM_MACOS)
	CFLocaleRef locale_ref = CFLocaleCopyCurrent();
	CFStringRef locale_identifier_ref = static_cast<CFStringRef>(CFLocaleGetValue(locale_ref, kCFLocaleIdentifier));

	// Count number of UTF16 codepoints, +1 for zero-termination.
	// Assume maximum possible length for encoding as UTF-8.
	CFIndex locale_identifier_size = (UTF8_BYTE_LENGTH * CFStringGetLength(locale_identifier_ref) + 1) * sizeof(char);
	char *locale_identifier = (char *)malloc(locale_identifier_size);
	dbg_assert(CFStringGetCString(locale_identifier_ref, locale_identifier, locale_identifier_size, kCFStringEncodingUTF8), "CFStringGetCString failure");

	str_copy(locale, locale_identifier, length);

	free(locale_identifier);
	CFRelease(locale_ref);
#else
	static const char *ENV_VARIABLES[] = {
		"LC_ALL",
		"LC_MESSAGES",
		"LANG",
	};

	locale[0] = '\0';
	for(const char *env_variable : ENV_VARIABLES)
	{
		const char *env_value = getenv(env_variable);
		if(env_value)
		{
			str_copy(locale, env_value, length);
			break;
		}
	}
#endif

	// Ensure RFC 3066 format:
	// - use hyphens instead of underscores
	// - truncate locale string after first non-standard letter
	for(int i = 0; i < str_length(locale); ++i)
	{
		if(locale[i] == '_')
		{
			locale[i] = '-';
		}
		else if(locale[i] != '-' && !(locale[i] >= 'a' && locale[i] <= 'z') && !(locale[i] >= 'A' && locale[i] <= 'Z') && !(str_isnum(locale[i])))
		{
			locale[i] = '\0';
			break;
		}
	}

	// Use default if we could not determine the locale,
	// i.e. if only the C or POSIX locale is available.
	if(locale[0] == '\0' || str_comp(locale, "C") == 0 || str_comp(locale, "POSIX") == 0)
		str_copy(locale, "en-US", length);
}
