/********************************************************/
/*  ntapi: Native API core library                      */
/*  Copyright (C) 2013--2021  SysDeer Technologies, LLC */
/*  Released under GPLv2 and GPLv3; see COPYING.NTAPI.  */
/********************************************************/

#include <psxtypes/psxtypes.h>
#include <ntapi/nt_ldr.h>
#include <ntapi/ntapi.h>
#include "ntapi_impl.h"

int32_t	__stdcall __ntapi_ldr_load_system_dll(
	__in	void *			hsysdir		__optional,
	__in	wchar16_t *		base_name,
	__in	uint16_t		base_name_size,
	__in	uint32_t *		image_flags	__optional,
	__out	void **			image_base)
{
	int32_t			status;
	void *			hkernel32;
	wchar16_t *		wch;
	wchar16_t *		cap;
	wchar16_t *		sysdir;
	nt_unicode_string	nt_sysdir;
	nt_unicode_string	nt_image_name;
	size_t			buffer[0x200/sizeof(size_t)];
	void *			(*load_library_ex_utf16)(
					wchar16_t *,
					void *,
					uint32_t);

	(void)image_flags;

	/* shell-style dos path */
	sysdir = (wchar16_t *)buffer;

	if ((status = __ntapi->tt_get_system_directory_dos_path(
			hsysdir,
			sysdir,sizeof(buffer),
			0,0,&nt_sysdir)))
		return status;

	sysdir = &sysdir[4];

	/* image */
	nt_image_name.strlen = base_name_size;
	nt_image_name.maxlen = base_name_size;
	nt_image_name.buffer = base_name;

	/* the logical way */
	status = __ntapi->ldr_load_dll(
		sysdir,0,
		&nt_image_name,
		image_base);

	/* eight point one big sigh support */
	if (status) {
		cap = &sysdir[sizeof(buffer)/sizeof(wchar16_t)];

		for (wch=sysdir; *wch; wch++)
			(void)0;

		if (&wch[base_name_size/sizeof(wchar16_t)] >= cap)
			return NT_STATUS_BUFFER_TOO_SMALL;

		if (!(hkernel32 = pe_get_kernel32_module_handle()))
			return NT_STATUS_INTERNAL_ERROR;

		if (!(load_library_ex_utf16 = pe_get_procedure_address(
				hkernel32,"LoadLibraryExW")))
			return NT_STATUS_INTERNAL_ERROR;

		__ntapi->tt_memcpy_utf16(
			wch,base_name,
			base_name_size);

		wch[base_name_size/sizeof(wchar16_t)] = 0;

		if ((*image_base = load_library_ex_utf16(sysdir,0,0)))
			status = NT_STATUS_SUCCESS;
	}

	/* downlevel... */
	if (status) {
		if (&wch[base_name_size/sizeof(wchar16_t)] >= &cap[-10])
			return NT_STATUS_BUFFER_TOO_SMALL;

		*wch++ = 'd';
		*wch++ = 'o';
		*wch++ = 'w';
		*wch++ = 'n';
		*wch++ = 'l';
		*wch++ = 'e';
		*wch++ = 'v';
		*wch++ = 'e';
		*wch++ = 'l';
		*wch++ = '\\';

		__ntapi->tt_memcpy_utf16(
			wch,base_name,
			base_name_size);

		wch[base_name_size/sizeof(wchar16_t)] = 0;

		if ((*image_base = load_library_ex_utf16(sysdir,0,0)))
			status = NT_STATUS_SUCCESS;
	}

	return status;
}