/*
 * Copyright (C) 2013 Martin Willi
 * Copyright (C) 2013 revosec AG
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 */

#include "utils.h"

#include <errno.h>

/**
 * See header
 */
void windows_init()
{
	WSADATA wsad;

	/* initialize winsock2 */
	WSAStartup(MAKEWORD(2, 2), &wsad);
}

/**
 * See header
 */
void windows_deinit()
{
	WSACleanup();
}

/**
 * See header
 */
int usleep(useconds_t usec)
{
	if (usec > 0 && usec < 1000)
	{	/* do not Sleep(0) for small values */
		usec = 1000;
	}
	SleepEx(usec / 1000, TRUE);
	return 0;
}

/**
 * See header.
 */
char* strndup(const char *s, size_t n)
{
	char *dst;

	n = min(strnlen(s, n), n);
	dst = malloc(n + 1);
	memcpy(dst, s, n);
	dst[n] = '\0';

	return dst;
}

/*
 * See header.
 */
void *dlopen(const char *filename, int flag)
{
	return LoadLibrary(filename);
}

/**
 * Load a symbol from known default libs (monolithic build)
 */
static void* dlsym_default(const char *name)
{
	const char *dlls[] = {
		"libstrongswan-0.dll",
		"libhydra-0.dll",
		"libcharon-0.dll",
		"libtnccs-0.dll",
		NULL /* .exe */
	};
	HANDLE handle;
	void *sym = NULL;
	int i;

	for (i = 0; i < countof(dlls); i++)
	{
		handle = GetModuleHandle(dlls[i]);
		if (handle)
		{
			sym = GetProcAddress(handle, name);
			if (sym)
			{
				break;
			}
		}
	}
	return sym;
}

/**
 * Emulate RTLD_NEXT for some known symbols
 */
static void* dlsym_next(const char *name)
{
	struct {
		const char *dll;
		const char *syms[4];
	} dlls[] = {
		/* for leak detective */
		{ "msvcrt",
			{ "malloc", "calloc", "realloc", "free" }
		},
	};
	HANDLE handle = NULL;
	int i, j;

	for (i = 0; i < countof(dlls); i++)
	{
		for (j = 0; j < countof(dlls[0].syms); j++)
		{
			if (dlls[i].syms[j] && streq(dlls[i].syms[j], name))
			{
				handle = GetModuleHandle(dlls[i].dll);
				break;
			}
		}
	}
	if (handle)
	{
		return GetProcAddress(handle, name);
	}
	return handle;
}

/**
 * See header.
 */
void* dlsym(void *handle, const char *symbol)
{
	if (handle == RTLD_DEFAULT)
	{
		return dlsym_default(symbol);
	}
	if (handle == RTLD_NEXT)
	{
		return dlsym_next(symbol);
	}
	return GetProcAddress((HMODULE)handle, symbol);
}

/**
 * See header.
 */
char* dlerror(void)
{
	static char buf[128];
	char *pos;
	DWORD err;

	err = GetLastError();
	if (FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
					  NULL, err, 0, buf, sizeof(buf), NULL) > 0)
	{
		pos = strchr(buf, '\n');
		if (pos)
		{
			*pos = '\0';
		}
	}
	else
	{
		snprintf(buf, sizeof(buf), "(%u)", err);
	}
	return buf;
}

/**
 * See header.
 */
int dlclose(void *handle)
{
	return FreeLibrary((HMODULE)handle);
}

/**
 * See header
 */
int socketpair(int domain, int type, int protocol, int sv[2])
{
	struct sockaddr_in addr = {
		.sin_family = AF_INET,
		.sin_addr.s_addr = htonl(INADDR_LOOPBACK),
	};
	socklen_t len = sizeof(addr);
	int s, c, sc;
	BOOL on;

	/* We don't check domain for AF_INET, as we use it as replacement for
	 * AF_UNIX. */
	if (type != SOCK_STREAM)
	{
		errno = EINVAL;
		return -1;
	}
	if (protocol != 0 && protocol != IPPROTO_TCP)
	{
		errno = EINVAL;
		return -1;
	}
	s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (s == -1)
	{
		return -1;
	}
	c = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (c == -1)
	{
		closesocket(c);
		return -1;
	}
	if (bind(s, (struct sockaddr*)&addr, sizeof(addr)) == 0 &&
		getsockname(s,(struct sockaddr*)&addr, &len) == 0 &&
		listen(s, 0) == 0 &&
		connect(c, (struct sockaddr*)&addr, sizeof(addr)) == 0)
	{
		sc = accept(s, NULL, NULL);
		if (sc > 0)
		{
			closesocket(s);
			s = sc;
			if (setsockopt(s, IPPROTO_TCP, TCP_NODELAY,
						   (void*)&on, sizeof(on)) == 0 &&
				setsockopt(c, IPPROTO_TCP, TCP_NODELAY,
						   (void*)&on, sizeof(on)) == 0)
			{
				sv[0] = s;
				sv[1] = c;
				return 0;
			}
		}
	}
	closesocket(s);
	closesocket(c);
	return -1;
}

/**
 * See header
 */
char* getpass(const char *prompt)
{
	static char buf[64] = "";
	char *pos;
	HANDLE in, out;
	DWORD mode, written = 0, total, done;

	out = GetStdHandle(STD_OUTPUT_HANDLE);
	in = GetStdHandle(STD_INPUT_HANDLE);

	if (out == INVALID_HANDLE_VALUE || in == INVALID_HANDLE_VALUE ||
		!GetConsoleMode(out, &mode) || !GetConsoleMode(in, &mode))
	{
		return NULL;
	}

	total = strlen(prompt);
	while (written < total)
	{
		if (!WriteConsole(out, prompt + written, total - written, &done, NULL))
		{
			return NULL;
		}
		written += done;
	}

	if (!SetConsoleMode(in, mode & ~ENABLE_ECHO_INPUT))
	{
		return NULL;
	}

	while (TRUE)
	{
		if (!ReadConsole(in, buf, sizeof(buf), &done, NULL))
		{
			SetConsoleMode(in, mode);
			return NULL;
		}
		if (done)
		{
			pos = strchr(buf, '\r');
			if (pos)
			{
				*pos = '\0';
			}
			break;
		}
	}
	SetConsoleMode(in, mode);

	/* append a newline, as we have no echo during input */
	WriteConsole(out, "\r\n", 2, &done, NULL);

	return buf;
}

/**
 * Set errno for a function setting WSA error on failure
 */
static int wserr(int retval)
{
	if (retval < 0)
	{
		switch (WSAGetLastError())
		{
			case WSANOTINITIALISED:
				errno = EBADF;
				break;
			case WSAENETDOWN:
				errno = ENETDOWN;
				break;
			case WSAENETRESET:
				errno = ENETRESET;
				break;
			case WSAESHUTDOWN:
				errno = ECONNABORTED;
				break;
			case WSAEACCES:
				errno = EACCES;
				break;
			case WSAEINTR:
				errno = EINTR;
				break;
			case WSAEINPROGRESS:
				errno = EINPROGRESS;
				break;
			case WSAEFAULT:
				errno = EFAULT;
				break;
			case WSAENOBUFS:
				errno = ENOBUFS;
				break;
			case WSAENOTSOCK:
				errno = ENOTSOCK;
				break;
			case WSAEOPNOTSUPP:
				errno = EOPNOTSUPP;
				break;
			case WSAEWOULDBLOCK:
				errno = EWOULDBLOCK;
				break;
			case WSAEMSGSIZE:
				errno = EMSGSIZE;
				break;
			case WSAEINVAL:
				errno = EINVAL;
				break;
			case WSAENOTCONN:
				errno = ENOTCONN;
				break;
			case WSAEHOSTUNREACH:
				errno = EHOSTUNREACH;
				break;
			case WSAECONNABORTED:
				errno = ECONNABORTED;
				break;
			case WSAECONNRESET:
				errno = ECONNRESET;
				break;
			case WSAETIMEDOUT:
				errno = ETIMEDOUT;
				break;
			default:
				errno = ENOENT;
				break;
		}
	}
	else
	{
		errno = 0;
	}
	return retval;
}

/**
 * Check and clear the dontwait flag
 */
static bool check_dontwait(int *flags)
{
	if (*flags & MSG_DONTWAIT)
	{
		*flags &= ~MSG_DONTWAIT;
		return TRUE;
	}
	return FALSE;
}

/**
 * See header
 */
#undef close
int windows_close(int fd)
{
	int ret;

	ret = close(fd);
	if (ret == -1 && errno == EBADF)
	{	/* Winsock socket? */
		ret = wserr(closesocket(fd));
	}
	return ret;
}

/**
 * See header
 */
#undef recv
ssize_t windows_recv(int sockfd, void *buf, size_t len, int flags)
{
	u_long on = 1, off = 0;
	ssize_t outlen = -1;

	if (!check_dontwait(&flags))
	{
		return wserr(recv(sockfd, buf, len, flags));
	}
	if (wserr(ioctlsocket(sockfd, FIONBIO, &on) == 0))
	{
		outlen = wserr(recv(sockfd, buf, len, flags));
		ioctlsocket(sockfd, FIONBIO, &off);
	}
	return outlen;
}

/**
 * See header
 */
#undef recvfrom
ssize_t windows_recvfrom(int sockfd, void *buf, size_t len, int flags,
						 struct sockaddr *src_addr, socklen_t *addrlen)
{
	u_long on = 1, off = 0;
	ssize_t outlen = -1;

	if (!check_dontwait(&flags))
	{
		return wserr(recvfrom(sockfd, buf, len, flags, src_addr, addrlen));
	}
	if (wserr(ioctlsocket(sockfd, FIONBIO, &on)) == 0)
	{
		outlen = wserr(recvfrom(sockfd, buf, len, flags, src_addr, addrlen));
		ioctlsocket(sockfd, FIONBIO, &off);
	}
	return outlen;
}

/**
 * See header
 */
#undef send
ssize_t windows_send(int sockfd, const void *buf, size_t len, int flags)
{
	u_long on = 1, off = 0;
	ssize_t outlen = -1;

	if (!check_dontwait(&flags))
	{
		return wserr(send(sockfd, buf, len, flags));
	}
	if (wserr(ioctlsocket(sockfd, FIONBIO, &on)) == 0)
	{
		outlen = wserr(send(sockfd, buf, len, flags));
		ioctlsocket(sockfd, FIONBIO, &off);
	}
	return outlen;
}

/**
 * See header
 */
#undef sendto
ssize_t windows_sendto(int sockfd, const void *buf, size_t len, int flags,
					   const struct sockaddr *dest_addr, socklen_t addrlen)
{
	u_long on = 1, off = 0;
	ssize_t outlen = -1;

	if (!check_dontwait(&flags))
	{
		return wserr(sendto(sockfd, buf, len, flags, dest_addr, addrlen));
	}
	if (wserr(ioctlsocket(sockfd, FIONBIO, &on)) == 0)
	{
		outlen = wserr(sendto(sockfd, buf, len, flags, dest_addr, addrlen));
		ioctlsocket(sockfd, FIONBIO, &off);
	}
	return outlen;
}