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Merged
fancycode merged 2 commits into from
Nov 2, 2017
Merged

Implement binary search for looking up exports by name. #76

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98b95ec
Implement binary search for looking up exports by name.
fancycode Nov 2, 2017
ac78ea1
Add test that loads a dll with lots of exports.
fancycode Nov 2, 2017
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Implement binary search for looking up exports by name. 
Code based on #74 which contained code from py2exe.
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@fancycode
fancycode committed Nov 2, 2017
commit 98b95eca4cc467fedded96386bcadaba3addf18e
73 changes: 60 additions & 13 deletions MemoryModule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,12 @@
* Portions created by Joachim Bauch are Copyright (C) 2004-2015
* Joachim Bauch. All Rights Reserved.
*
*
* THeller: Added binary search in MemoryGetProcAddress function
* (#define USE_BINARY_SEARCH to enable it). This gives a very large
* speedup for libraries that exports lots of functions.
*
* These portions are Copyright (C) 2013 Thomas Heller.
*/

#include <windows.h>
Expand Down Expand Up @@ -56,6 +62,11 @@

#include "MemoryModule.h"

struct ExportNameEntry {
LPCSTR name;
WORD idx;
};

typedef BOOL (WINAPI *DllEntryProc)(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpReserved);
typedef int (WINAPI *ExeEntryProc)(void);

Expand All @@ -72,6 +83,7 @@ typedef struct {
CustomLoadLibraryFunc loadLibrary;
CustomGetProcAddressFunc getProcAddress;
CustomFreeLibraryFunc freeLibrary;
struct ExportNameEntry *nameExportsTable;
void *userdata;
ExeEntryProc exeEntry;
DWORD pageSize;
Expand Down Expand Up @@ -688,12 +700,27 @@ HMEMORYMODULE MemoryLoadLibraryEx(const void *data, size_t size,
return NULL;
}

FARPROC MemoryGetProcAddress(HMEMORYMODULE module, LPCSTR name)
static int _compare(const void *a, const void *b)
{
const struct ExportNameEntry *p1 = (const struct ExportNameEntry*) a;
const struct ExportNameEntry *p2 = (const struct ExportNameEntry*) b;
return _stricmp(p1->name, p2->name);
}

static int _find(const void *a, const void *b)
{
LPCSTR *name = (LPCSTR *) a;
const struct ExportNameEntry *p = (const struct ExportNameEntry*) b;
return _stricmp(*name, p->name);
}

FARPROC MemoryGetProcAddress(HMEMORYMODULE mod, LPCSTR name)
{
unsigned char *codeBase = ((PMEMORYMODULE)module)->codeBase;
PMEMORYMODULE module = (PMEMORYMODULE)mod;
unsigned char *codeBase = module->codeBase;
DWORD idx = 0;
PIMAGE_EXPORT_DIRECTORY exports;
PIMAGE_DATA_DIRECTORY directory = GET_HEADER_DICTIONARY((PMEMORYMODULE)module, IMAGE_DIRECTORY_ENTRY_EXPORT);
PIMAGE_DATA_DIRECTORY directory = GET_HEADER_DICTIONARY(module, IMAGE_DIRECTORY_ENTRY_EXPORT);
if (directory->Size == 0) {
// no export table found
SetLastError(ERROR_PROC_NOT_FOUND);
Expand All @@ -715,25 +742,44 @@ FARPROC MemoryGetProcAddress(HMEMORYMODULE module, LPCSTR name)
}

idx = LOWORD(name) - exports->Base;
} else if (!exports->NumberOfNames) {
SetLastError(ERROR_PROC_NOT_FOUND);
return NULL;
} else {
// search function name in list of exported names
DWORD i;
DWORD *nameRef = (DWORD *) (codeBase + exports->AddressOfNames);
WORD *ordinal = (WORD *) (codeBase + exports->AddressOfNameOrdinals);
BOOL found = FALSE;
for (i=0; i<exports->NumberOfNames; i++, nameRef++, ordinal++) {
if (_stricmp(name, (const char *) (codeBase + (*nameRef))) == 0) {
idx = *ordinal;
found = TRUE;
break;
const struct ExportNameEntry *found;

// Lazily build name table and sort it by names
if (!module->nameExportsTable) {
DWORD i;
DWORD *nameRef = (DWORD *) (codeBase + exports->AddressOfNames);
WORD *ordinal = (WORD *) (codeBase + exports->AddressOfNameOrdinals);
struct ExportNameEntry *entry = (struct ExportNameEntry*) malloc(exports->NumberOfNames * sizeof(struct ExportNameEntry));
module->nameExportsTable = entry;
if (!entry) {
SetLastError(ERROR_OUTOFMEMORY);
return NULL;
}
for (i=0; i<exports->NumberOfNames; i++, nameRef++, ordinal++, entry++) {
entry->name = (const char *) (codeBase + (*nameRef));
entry->idx = *ordinal;
}
qsort(module->nameExportsTable,
exports->NumberOfNames,
sizeof(struct ExportNameEntry), _compare);
}

// search function name in list of exported names with binary search
found = (const struct ExportNameEntry*) bsearch(&name,
module->nameExportsTable,
exports->NumberOfNames,
sizeof(struct ExportNameEntry), _find);
if (!found) {
// exported symbol not found
SetLastError(ERROR_PROC_NOT_FOUND);
return NULL;
}

idx = found->idx;
}

if (idx > exports->NumberOfFunctions) {
Expand All @@ -759,6 +805,7 @@ void MemoryFreeLibrary(HMEMORYMODULE mod)
(*DllEntry)((HINSTANCE)module->codeBase, DLL_PROCESS_DETACH, 0);
}

free(module->nameExportsTable);
if (module->modules != NULL) {
// free previously opened libraries
int i;
Expand Down