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Loading DLLs from memory

Moderators: kris

bobef

Joined: 06/05/05

Posts: 86

Posted: 03/05/08 13:52:06

I would like to see thins in SharedLib?. Tested with simple dll on win xp sp2 and it works fine, not tested in real world (yet).

/*
 * Memory DLL loading code
 * Version 0.0.2
 *
 * Copyright (c) 2004-2005 by Joachim Bauch / mail@joachim-bauch.de
 * http://www.joachim-bauch.de
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is MemoryModule.c
 *
 * The Initial Developer of the Original Code is Joachim Bauch.
 *
 * Portions created by Joachim Bauch are Copyright (C) 2004-2005
 * Joachim Bauch. All Rights Reserved.
 *
 */

// disable warnings about pointer <. DWORD conversions
//#pragma warning( disable : 4311 4312 )

import tango.sys.win32.Types;
import tango.stdc.stdlib;
import tango.stdc.string;

version(DEBUG_OUTPUT)
{
//#include <stdio.h>
}

extern(C) int    stricmp(char* s1, char* s2);
extern(Windows)
{
	WINBOOL HeapFree(HANDLE, DWORD, LPVOID);
	WINBOOL FreeLibrary(HINST);
	LPVOID HeapAlloc(HANDLE, DWORD, DWORD);
	HANDLE GetProcessHeap();
	HINST LoadLibraryA(LPCSTR);
	FARPROC GetProcAddress(HINST, LPCSTR);
	LPVOID VirtualAlloc(LPVOID, DWORD, DWORD, DWORD);
	WINBOOL VirtualFree(LPVOID, DWORD, DWORD);
	WINBOOL VirtualProtect(LPVOID, DWORD, DWORD, PDWORD);
	WINBOOL IsBadReadPtr(POINTER, UINT);
}

const IMAGE_SIZEOF_BASE_RELOCATION=         8;
const IMAGE_REL_BASED_ABSOLUTE=             0;
const IMAGE_REL_BASED_HIGHLOW=              3;
const IMAGE_DIRECTORY_ENTRY_EXPORT=          0;   // Export Directory
const IMAGE_DIRECTORY_ENTRY_IMPORT=          1;   // Import Directory
const IMAGE_DIRECTORY_ENTRY_RESOURCE=        2;   // Resource Directory
const IMAGE_DIRECTORY_ENTRY_EXCEPTION=       3;   // Exception Directory
const IMAGE_DIRECTORY_ENTRY_SECURITY=        4;   // Security Directory
const IMAGE_DIRECTORY_ENTRY_BASERELOC=       5;   // Base Relocation Table
const IMAGE_DIRECTORY_ENTRY_DEBUG=           6;   // Debug Directory
const IMAGE_DIRECTORY_ENTRY_ARCHITECTURE=    7;   // Architecture Specific Data
const IMAGE_DIRECTORY_ENTRY_GLOBALPTR=       8;   // RVA of GP
const IMAGE_DIRECTORY_ENTRY_TLS=             9;   // TLS Directory
const IMAGE_DIRECTORY_ENTRY_LOAD_CONFIG=    10;   // Load Configuration Directory
const IMAGE_DIRECTORY_ENTRY_BOUND_IMPORT=   11;   // Bound Import Directory in headers
const IMAGE_DIRECTORY_ENTRY_IAT=            12;   // Import Address Table
const IMAGE_DIRECTORY_ENTRY_DELAY_IMPORT=   13;   // Delay Load Import Descriptors
const IMAGE_DIRECTORY_ENTRY_COM_DESCRIPTOR= 14;   // COM Runtime descriptor
const IMAGE_SCN_LNK_NRELOC_OVFL=            0x01000000;  // Section contains extended relocations.
const IMAGE_SCN_MEM_DISCARDABLE=            0x02000000;  // Section can be discarded.
const IMAGE_SCN_MEM_NOT_CACHED=             0x04000000;  // Section is not cachable.
const IMAGE_SCN_MEM_NOT_PAGED=              0x08000000;  // Section is not pageable.
const IMAGE_SCN_MEM_SHARED=                 0x10000000;  // Section is shareable.
const IMAGE_SCN_MEM_EXECUTE=                0x20000000;  // Section is executable.
const IMAGE_SCN_MEM_READ=                   0x40000000;  // Section is readable.
const IMAGE_SCN_MEM_WRITE=                  0x80000000;  // Section is writeable.
const IMAGE_SCN_CNT_INITIALIZED_DATA=       0x00000040;  // Section contains initialized data.
const IMAGE_SCN_CNT_UNINITIALIZED_DATA=     0x00000080;  // Section contains uninitialized data.

const IMAGE_ORDINAL_FLAG = 0x80000000;
bool IMAGE_SNAP_BY_ORDINAL(DWORD o) {return (o&IMAGE_ORDINAL_FLAG)!=0; }
DWORD IMAGE_ORDINAL32(DWORD Ordinal) { return Ordinal & 0xffff; }
alias IMAGE_ORDINAL32 IMAGE_ORDINAL;

alias void* HMEMORYMODULE;

struct IMAGE_DOS_HEADER {	  // DOS .EXE header
	WORD   e_magic;					 // Magic number
	WORD   e_cblp;					  // Bytes on last page of file
	WORD   e_cp;						// Pages in file
	WORD   e_crlc;					  // Relocations
	WORD   e_cparhdr;				   // Size of header in paragraphs
	WORD   e_minalloc;				  // Minimum extra paragraphs needed
	WORD   e_maxalloc;				  // Maximum extra paragraphs needed
	WORD   e_ss;						// Initial (relative) SS value
	WORD   e_sp;						// Initial SP value
	WORD   e_csum;					  // Checksum
	WORD   e_ip;						// Initial IP value
	WORD   e_cs;						// Initial (relative) CS value
	WORD   e_lfarlc;					// File address of relocation table
	WORD   e_ovno;					  // Overlay number
	WORD   e_res[4];					// Reserved words
	WORD   e_oemid;					 // OEM identifier (for e_oeminfo)
	WORD   e_oeminfo;				   // OEM information; e_oemid specific
	WORD   e_res2[10];				  // Reserved words
	LONG   e_lfanew;					// File address of new exe header
}

alias IMAGE_DOS_HEADER* PIMAGE_DOS_HEADER;

struct IMAGE_IMPORT_BY_NAME {
    WORD    Hint;
    BYTE    Name[1];
}

alias IMAGE_IMPORT_BY_NAME* PIMAGE_IMPORT_BY_NAME;

struct IMAGE_NT_HEADERS {
	DWORD Signature;
	IMAGE_FILE_HEADER FileHeader;
	IMAGE_OPTIONAL_HEADER32 OptionalHeader;
}

alias IMAGE_NT_HEADERS* PIMAGE_NT_HEADERS;

//LONG FIELD_OFFSET(type,field){ return cast(LONG)cast(LONG_PTR)&((cast(type*)null).field); }

PIMAGE_SECTION_HEADER IMAGE_FIRST_SECTION( PIMAGE_NT_HEADERS ntheader )
{
	return cast(PIMAGE_SECTION_HEADER)(
		cast(DWORD)ntheader + 
		cast(LONG)cast(LONG_PTR)&((cast(IMAGE_NT_HEADERS*)null).OptionalHeader) + 
		(cast(PIMAGE_NT_HEADERS)(ntheader)).FileHeader.SizeOfOptionalHeader
	);
}

struct IMAGE_FILE_HEADER {
	WORD	Machine;
	WORD	NumberOfSections;
	DWORD   TimeDateStamp;
	DWORD   PointerToSymbolTable;
	DWORD   NumberOfSymbols;
	WORD	SizeOfOptionalHeader;
	WORD	Characteristics;
}

alias IMAGE_FILE_HEADER* PIMAGE_FILE_HEADER;

struct IMAGE_DATA_DIRECTORY {
	DWORD VirtualAddress;
	DWORD Size;
} 

alias IMAGE_DATA_DIRECTORY* PIMAGE_DATA_DIRECTORY;

const IMAGE_NUMBEROF_DIRECTORY_ENTRIES = 16;
const IMAGE_SIZEOF_SHORT_NAME = 8;

struct IMAGE_OPTIONAL_HEADER32 {
	//
	// Standard fields.
	//

	WORD	Magic;
	BYTE	MajorLinkerVersion;
	BYTE	MinorLinkerVersion;
	DWORD   SizeOfCode;
	DWORD   SizeOfInitializedData;
	DWORD   SizeOfUninitializedData;
	DWORD   AddressOfEntryPoint;
	DWORD   BaseOfCode;
	DWORD   BaseOfData;

	//
	// NT additional fields.
	//

	DWORD   ImageBase;
	DWORD   SectionAlignment;
	DWORD   FileAlignment;
	WORD	MajorOperatingSystemVersion;
	WORD	MinorOperatingSystemVersion;
	WORD	MajorImageVersion;
	WORD	MinorImageVersion;
	WORD	MajorSubsystemVersion;
	WORD	MinorSubsystemVersion;
	DWORD   Win32VersionValue;
	DWORD   SizeOfImage;
	DWORD   SizeOfHeaders;
	DWORD   CheckSum;
	WORD	Subsystem;
	WORD	DllCharacteristics;
	DWORD   SizeOfStackReserve;
	DWORD   SizeOfStackCommit;
	DWORD   SizeOfHeapReserve;
	DWORD   SizeOfHeapCommit;
	DWORD   LoaderFlags;
	DWORD   NumberOfRvaAndSizes;
	IMAGE_DATA_DIRECTORY DataDirectory[IMAGE_NUMBEROF_DIRECTORY_ENTRIES];
}

alias IMAGE_OPTIONAL_HEADER32* PIMAGE_OPTIONAL_HEADER32;

struct IMAGE_SECTION_HEADER {
	BYTE	Name[IMAGE_SIZEOF_SHORT_NAME];
	union _Misc {
			DWORD   PhysicalAddress;
			DWORD   VirtualSize;
	}
	_Misc Misc;
	DWORD   VirtualAddress;
	DWORD   SizeOfRawData;
	DWORD   PointerToRawData;
	DWORD   PointerToRelocations;
	DWORD   PointerToLinenumbers;
	WORD	NumberOfRelocations;
	WORD	NumberOfLinenumbers;
	DWORD   Characteristics;
}

alias IMAGE_SECTION_HEADER* PIMAGE_SECTION_HEADER;

struct IMAGE_BASE_RELOCATION {
	DWORD   VirtualAddress;
	DWORD   SizeOfBlock;
}

alias IMAGE_BASE_RELOCATION* PIMAGE_BASE_RELOCATION;

struct IMAGE_IMPORT_DESCRIPTOR {
	union {
		DWORD   Characteristics;			// 0 for terminating null import descriptor
		DWORD   OriginalFirstThunk;		 // RVA to original unbound IAT (PIMAGE_THUNK_DATA)
	}
	DWORD   TimeDateStamp;				  // 0 if not bound,
											// -1 if bound, and real date\time stamp
											//	 in IMAGE_DIRECTORY_ENTRY_BOUND_IMPORT (new BIND)
											// O.W. date/time stamp of DLL bound to (Old BIND)

	DWORD   ForwarderChain;				 // -1 if no forwarders
	DWORD   Name;
	DWORD   FirstThunk;					 // RVA to IAT (if bound this IAT has actual addresses)
}

alias IMAGE_IMPORT_DESCRIPTOR* PIMAGE_IMPORT_DESCRIPTOR;

struct IMAGE_EXPORT_DIRECTORY {
	DWORD   Characteristics;
	DWORD   TimeDateStamp;
	WORD	MajorVersion;
	WORD	MinorVersion;
	DWORD   Name;
	DWORD   Base;
	DWORD   NumberOfFunctions;
	DWORD   NumberOfNames;
	DWORD   AddressOfFunctions;	 // RVA from base of image
	DWORD   AddressOfNames;		 // RVA from base of image
	DWORD   AddressOfNameOrdinals;  // RVA from base of image
}

alias IMAGE_EXPORT_DIRECTORY* PIMAGE_EXPORT_DIRECTORY;

struct MEMORYMODULE {
	PIMAGE_NT_HEADERS headers;
	ubyte *codeBase;
	HMODULE *modules;
	int numModules;
	int initialized;
}

alias MEMORYMODULE* PMEMORYMODULE;

extern(Windows) alias BOOL function(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpReserved) DllEntryProc;

IMAGE_DATA_DIRECTORY* GET_HEADER_DICTIONARY(MEMORYMODULE* mod,int idx){return &mod.headers.OptionalHeader.DataDirectory[idx];}

version(DEBUG_OUTPUT)
{
void OutputLastError(char *msg)
{
	LPVOID tmp;
	char *tmpmsg;
	FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
		null, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR)&tmp, 0, null);
	tmpmsg = cast(char *)LocalAlloc(LPTR, strlen(msg) + strlen(tmp) + 3);
	sprintf(tmpmsg, "%s: %s", msg, tmp);
	OutputDebugString(tmpmsg);
	LocalFree(tmpmsg);
	LocalFree(tmp);
}
}

void CopySections(ubyte *data, PIMAGE_NT_HEADERS old_headers, PMEMORYMODULE modul)
{
	int i, size;
	ubyte *codeBase = modul.codeBase;
	ubyte *dest;
	PIMAGE_SECTION_HEADER section = IMAGE_FIRST_SECTION(modul.headers);
	for (i=0; i<modul.headers.FileHeader.NumberOfSections; i++, section++)
	{
		if (section.SizeOfRawData == 0)
		{
			// section doesn't contain data in the dll itself, but may define
			// uninitialized data
			size = old_headers.OptionalHeader.SectionAlignment;
			if (size > 0)
			{
				dest = cast(ubyte *)VirtualAlloc(codeBase + section.VirtualAddress,
					size,
					MEM_COMMIT,
					PAGE_READWRITE);

				section.Misc.PhysicalAddress = cast(DWORD)dest;
				memset(dest, 0, size);
			}

			// section is empty
			continue;
		}

		// commit memory block and copy data from dll
		dest = cast(ubyte *)VirtualAlloc(codeBase + section.VirtualAddress,
							section.SizeOfRawData,
							MEM_COMMIT,
							PAGE_READWRITE);
		memcpy(dest, data + section.PointerToRawData, section.SizeOfRawData);
		section.Misc.PhysicalAddress = cast(DWORD)dest;
	}
}

// Protection flags for memory pages (Executable, Readable, Writeable)
static int ProtectionFlags[2][2][2] = [
	[
		// not executable
		[PAGE_NOACCESS, PAGE_WRITECOPY],
		[PAGE_READONLY, PAGE_READWRITE],
	], [
		// executable
		[PAGE_EXECUTE, PAGE_EXECUTE_WRITECOPY],
		[PAGE_EXECUTE_READ, PAGE_EXECUTE_READWRITE],
	],
];

void FinalizeSections(PMEMORYMODULE modul)
{
	int i;
	PIMAGE_SECTION_HEADER section = IMAGE_FIRST_SECTION(modul.headers);
	
	// loop through all sections and change access flags
	for (i=0; i<modul.headers.FileHeader.NumberOfSections; i++, section++)
	{
		DWORD protect, oldProtect, size;
		int executable = (section.Characteristics & IMAGE_SCN_MEM_EXECUTE) != 0;
		int readable =   (section.Characteristics & IMAGE_SCN_MEM_READ) != 0;
		int writeable =  (section.Characteristics & IMAGE_SCN_MEM_WRITE) != 0;

		if (section.Characteristics & IMAGE_SCN_MEM_DISCARDABLE)
		{
			// section is not needed any more and can safely be freed
			VirtualFree(cast(LPVOID)section.Misc.PhysicalAddress, section.SizeOfRawData, MEM_DECOMMIT);
			continue;
		}

		// determine protection flags based on characteristics
		protect = ProtectionFlags[executable][readable][writeable];
		if (section.Characteristics & IMAGE_SCN_MEM_NOT_CACHED)
			protect |= PAGE_NOCACHE;

		// determine size of region
		size = section.SizeOfRawData;
		if (size == 0)
		{
			if (section.Characteristics & IMAGE_SCN_CNT_INITIALIZED_DATA)
				size = modul.headers.OptionalHeader.SizeOfInitializedData;
			else if (section.Characteristics & IMAGE_SCN_CNT_UNINITIALIZED_DATA)
				size = modul.headers.OptionalHeader.SizeOfUninitializedData;
		}

		if (size > 0)
		{
			// change memory access flags
			if (VirtualProtect(cast(LPVOID)section.Misc.PhysicalAddress, section.SizeOfRawData, protect, &oldProtect) == 0)
			{
				version(DEBUG_OUTPUT) OutputLastError("Error protecting memory page");
			}
		}
	}
}

void PerformBaseRelocation(PMEMORYMODULE modul, DWORD delta)
{
	DWORD i;
	ubyte *codeBase = modul.codeBase;

	PIMAGE_DATA_DIRECTORY directory = GET_HEADER_DICTIONARY(modul, IMAGE_DIRECTORY_ENTRY_BASERELOC);
	if (directory.Size > 0)
	{
		PIMAGE_BASE_RELOCATION relocation = cast(PIMAGE_BASE_RELOCATION)(codeBase + directory.VirtualAddress);
		for (; relocation.VirtualAddress > 0; )
		{
			ubyte *dest = cast(ubyte *)(codeBase + relocation.VirtualAddress);
			ushort *relInfo = cast(ushort *)(cast(ubyte *)relocation + IMAGE_SIZEOF_BASE_RELOCATION);
			for (i=0; i<((relocation.SizeOfBlock-IMAGE_SIZEOF_BASE_RELOCATION) / 2); i++, relInfo++)
			{
				DWORD *patchAddrHL;
				int type, offset;

				// the upper 4 bits define the type of relocation
				type = *relInfo >> 12;
				// the lower 12 bits define the offset
				offset = *relInfo & 0xfff;
				
				switch (type)
				{
				case IMAGE_REL_BASED_ABSOLUTE:
					// skip relocation
					break;

				case IMAGE_REL_BASED_HIGHLOW:
					// change complete 32 bit address
					patchAddrHL = cast(DWORD *)(dest + offset);
					*patchAddrHL += delta;
					break;

				default:
					//printf("Unknown relocation: %d\n", type);
					break;
				}
			}

			// advance to next relocation block
			relocation = cast(PIMAGE_BASE_RELOCATION)((cast(DWORD)relocation) + relocation.SizeOfBlock);
		}
	}
}

int BuildImportTable(PMEMORYMODULE modul)
{
	int result=1;
	ubyte *codeBase = modul.codeBase;

	PIMAGE_DATA_DIRECTORY directory = GET_HEADER_DICTIONARY(modul, IMAGE_DIRECTORY_ENTRY_IMPORT);
	if (directory.Size > 0)
	{
		PIMAGE_IMPORT_DESCRIPTOR importDesc = cast(PIMAGE_IMPORT_DESCRIPTOR)(codeBase + directory.VirtualAddress);
		for (; !IsBadReadPtr(importDesc, IMAGE_IMPORT_DESCRIPTOR.sizeof) && importDesc.Name; importDesc++)
		{
			DWORD* thunkRef,funcRef;
			HMODULE handle = LoadLibraryA(cast(LPCSTR)(codeBase + importDesc.Name));
			if (handle == INVALID_HANDLE_VALUE)
			{
				version(DEBUG_OUTPUT) OutputLastError("Can't load library");
				result = 0;
				break;
			}

			modul.modules = cast(HMODULE *)realloc(modul.modules, (modul.numModules+1)*(HMODULE.sizeof));
			if (modul.modules == null)
			{
				result = 0;
				break;
			}

			modul.modules[modul.numModules++] = handle;
			if (importDesc.OriginalFirstThunk)
			{
				thunkRef = cast(DWORD *)(codeBase + importDesc.OriginalFirstThunk);
				funcRef = cast(DWORD *)(codeBase + importDesc.FirstThunk);
			} else {
				// no hint table
				thunkRef = cast(DWORD *)(codeBase + importDesc.FirstThunk);
				funcRef = cast(DWORD *)(codeBase + importDesc.FirstThunk);
			}
			for (; *thunkRef; thunkRef++, funcRef++)
			{
				if(IMAGE_SNAP_BY_ORDINAL(*thunkRef))
					*funcRef = cast(DWORD)GetProcAddress(handle, cast(LPCSTR)IMAGE_ORDINAL(*thunkRef));
				else {
					PIMAGE_IMPORT_BY_NAME thunkData = cast(PIMAGE_IMPORT_BY_NAME)(codeBase + *thunkRef);
					*funcRef = cast(DWORD)GetProcAddress(handle, cast(LPCSTR)&thunkData.Name);
				}
				if (*funcRef == 0)
				{
					result = 0;
					break;
				}
			}

			if (!result)
				break;
		}
	}

	return result;
}

HMEMORYMODULE MemoryLoadLibrary(void *data)
{
	PMEMORYMODULE result;
	PIMAGE_DOS_HEADER dos_header;
	PIMAGE_NT_HEADERS old_header;
	ubyte *code,headers;
	DWORD locationDelta;
	DllEntryProc DllEntry;
	BOOL successfull;

	dos_header = cast(PIMAGE_DOS_HEADER)data;
	if (dos_header.e_magic != IMAGE_DOS_SIGNATURE)
	{
		version(DEBUG_OUTPUT) OutputDebugString("Not a valid executable file.\n");
		return null;
	}

	old_header = cast(PIMAGE_NT_HEADERS)&(cast(ubyte *)(data))[dos_header.e_lfanew];
	if (old_header.Signature != IMAGE_NT_SIGNATURE)
	{
		version(DEBUG_OUTPUT) OutputDebugString("No PE header found.\n");
		return null;
	}

	// reserve memory for image of library
	code = cast(ubyte *)VirtualAlloc(cast(LPVOID)(old_header.OptionalHeader.ImageBase),
		old_header.OptionalHeader.SizeOfImage,
		MEM_RESERVE,
		PAGE_READWRITE);

	if (code == null)
		// try to allocate memory at arbitrary position
		code = cast(ubyte *)VirtualAlloc(null,
			old_header.OptionalHeader.SizeOfImage,
			MEM_RESERVE,
			PAGE_READWRITE);
	
	if (code == null)
	{
		version(DEBUG_OUTPUT) OutputLastError("Can't reserve memory");
		return null;
	}

	result = cast(PMEMORYMODULE)HeapAlloc(GetProcessHeap(), 0, MEMORYMODULE.sizeof);
	result.codeBase = code;
	result.numModules = 0;
	result.modules = null;
	result.initialized = 0;

	// XXX: is it correct to commit the complete memory region at once?
	//	  calling DllEntry raises an exception if we don't...
	VirtualAlloc(code,
		old_header.OptionalHeader.SizeOfImage,
		MEM_COMMIT,
		PAGE_READWRITE);

	// commit memory for headers
	headers = cast(ubyte *)VirtualAlloc(code,
		old_header.OptionalHeader.SizeOfHeaders,
		MEM_COMMIT,
		PAGE_READWRITE);
	
	// copy PE header to code
	memcpy(headers, dos_header, dos_header.e_lfanew + old_header.OptionalHeader.SizeOfHeaders);
	result.headers = cast(PIMAGE_NT_HEADERS)&(cast(ubyte *)(headers))[dos_header.e_lfanew];

	// update position
	result.headers.OptionalHeader.ImageBase = cast(DWORD)code;

	// copy sections from DLL file block to new memory location
	CopySections(cast(ubyte*)data, old_header, result);

	// adjust base address of imported data
	locationDelta = cast(DWORD)(code - old_header.OptionalHeader.ImageBase);
	if (locationDelta != 0)
		PerformBaseRelocation(result, locationDelta);

	// load required dlls and adjust function table of imports
	if (!BuildImportTable(result))
		goto error;

	// mark memory pages depending on section headers and release
	// sections that are marked as "discardable"
	FinalizeSections(result);

	// get entry point of loaded library
	if (result.headers.OptionalHeader.AddressOfEntryPoint != 0)
	{
		DllEntry = cast(DllEntryProc)cast(void*)(code + result.headers.OptionalHeader.AddressOfEntryPoint);
		if (DllEntry is null)
		{
			version(DEBUG_OUTPUT) OutputDebugString("Library has no entry point.\n");
			goto error;
		}

		// notify library about attaching to process
		successfull = (*DllEntry)(cast(HINSTANCE)code, DLL_PROCESS_ATTACH, null);
		if (!successfull)
		{
			version(DEBUG_OUTPUT) OutputDebugString("Can't attach library.\n");
			goto error;
		}
		result.initialized = 1;
	}

	return cast(HMEMORYMODULE)result;

error:
	// cleanup
	MemoryFreeLibrary(result);
	return null;
}

FARPROC MemoryGetProcAddress(HMEMORYMODULE modul, char *name)
{
	ubyte *codeBase = (cast(PMEMORYMODULE)modul).codeBase;
	int idx=-1;
	DWORD i;
	DWORD* nameRef;
	WORD *ordinal;
	PIMAGE_EXPORT_DIRECTORY exports;
	PIMAGE_DATA_DIRECTORY directory = GET_HEADER_DICTIONARY(cast(PMEMORYMODULE)modul, IMAGE_DIRECTORY_ENTRY_EXPORT);
	if (directory.Size == 0)
		// no export table found
		return null;

	exports = cast(PIMAGE_EXPORT_DIRECTORY)(codeBase + directory.VirtualAddress);
	if (exports.NumberOfNames == 0 || exports.NumberOfFunctions == 0)
		// DLL doesn't export anything
		return null;

	// search function name in list of exported names
	nameRef = cast(DWORD *)(codeBase + exports.AddressOfNames);
	ordinal = cast(WORD *)(codeBase + exports.AddressOfNameOrdinals);
	for (i=0; i<exports.NumberOfNames; i++, nameRef++, ordinal++)
		if (stricmp(name, cast(char *)(codeBase + *nameRef)) == 0)
		{
			idx = *ordinal;
			break;
		}

	if (idx == -1)
		// exported symbol not found
		return null;

	if (cast(DWORD)idx > exports.NumberOfFunctions)
		// name <. ordinal number don't match
		return null;

	// AddressOfFunctions contains the RVAs to the "real" functions
	return cast(FARPROC)(codeBase + *cast(DWORD *)(codeBase + exports.AddressOfFunctions + (idx*4)));
}

void MemoryFreeLibrary(HMEMORYMODULE mod)
{
	int i;
	PMEMORYMODULE modul = cast(PMEMORYMODULE)mod;

	if (modul != null)
	{
		if (modul.initialized != 0)
		{
			// notify library about detaching from process
			DllEntryProc DllEntry = cast(DllEntryProc)(modul.codeBase + modul.headers.OptionalHeader.AddressOfEntryPoint);
			(*DllEntry)(cast(HINSTANCE)modul.codeBase, DLL_PROCESS_DETACH, null);
			modul.initialized = 0;
		}

		if (modul.modules != null)
		{
			// free previously opened libraries
			for (i=0; i<modul.numModules; i++)
				if (modul.modules[i] != INVALID_HANDLE_VALUE)
					FreeLibrary(modul.modules[i]);

			free(modul.modules);
		}

		if (modul.codeBase != null)
			// release memory of library
			VirtualFree(modul.codeBase, 0, MEM_RELEASE);

		HeapFree(GetProcessHeap(), 0, modul);
	}
}

Author Message

bobef

Joined: 06/05/05

Posts: 86

Posted: 03/06/08 12:26:43

Tested with HTMLayout, FMOD, SumatraPDF and few more. All work nicely.