/********************************************************/

/*  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 <pemagine/pemagine.h>

#include <dalist/dalist.h>

#include <ntapi/ntapi.h>

#include "ntapi_impl.h"

struct callback_ctx {

	struct dalist_ex *		ldr_state_snapshot;

	struct pe_ldr_tbl_entry *	ldr_tbl_entry;

	void *				image_base;

	uint32_t			load_count;

	int32_t				status;

};

static int __cdecl __find_next_module_to_unload(

	struct pe_ldr_tbl_entry *	ldr_tbl_entry,

	enum pe_callback_reason		int_callback_reason,

	void *				context)

{

	struct dalist_node *	node;

	struct callback_ctx *	ctx;

	ctx = (struct callback_ctx *)context;

	if (int_callback_reason == PE_CALLBACK_REASON_ERROR) {

		ctx->status = NT_STATUS_UNSUCCESSFUL;

		return ctx->status;

	} else if (int_callback_reason != PE_CALLBACK_REASON_ITEM) {

		ctx->status = NT_STATUS_SUCCESS;

		return 1;

	} else if (!ldr_tbl_entry->dll_base) {

		ctx->status = NT_STATUS_SUCCESS;

		return 1;

	}

	ctx->status = dalist_get_node_by_key(

		ctx->ldr_state_snapshot,

		(struct dalist_node_ex **)&node,

		(uintptr_t)ldr_tbl_entry->dll_base,

		DALIST_NODE_TYPE_EXISTING,

		0);

	if (ctx->status != DALIST_OK)

		return -1;

	else if (node)

		return 1;

	else if (!ctx->image_base || (ldr_tbl_entry->load_count < ctx->load_count)) {

			ctx->image_base = ldr_tbl_entry->dll_base;

			ctx->load_count = ldr_tbl_entry->load_count;

			ctx->ldr_tbl_entry = ldr_tbl_entry;

	}

	return 1;

}

int __cdecl __ntapi_ldr_revert_state_to_snapshot(

	__in	struct dalist_ex * ldr_state_snapshot)

{

	struct callback_ctx	ctx;

	uint32_t		i;

	if (!ldr_state_snapshot->free && !ldr_state_snapshot->memfn_ptr)

		return NT_STATUS_BUFFER_TOO_SMALL;

	ctx.ldr_state_snapshot = ldr_state_snapshot;

	ctx.image_base = (void *)0;

	ctx.load_count = 0;

	pe_enum_modules_in_load_order(

		__find_next_module_to_unload,

		&ctx;;

	while ((ctx.image_base) && (ctx.status == NT_STATUS_SUCCESS)) {

			if (ctx.load_count == 0xffff) {

				ctx.load_count = 1;

				ctx.ldr_tbl_entry->load_count = 1;

				ctx.ldr_tbl_entry->entry_point = (void *)0;

				ctx.ldr_tbl_entry->flags = 0;

			}

			for (i=0; i

				__ntapi->ldr_unload_dll(ctx.image_base);

			__ntapi->zw_unmap_view_of_section(

				NT_CURRENT_PROCESS_HANDLE,

				ctx.image_base);

		ctx.image_base = (void *)0;

		ctx.load_count = 0;

		pe_enum_modules_in_load_order(

			__find_next_module_to_unload,

			&ctx;;

	}

	return ctx.status;

}