How to extract Exported functions from a DLL

[Nibu babu thomas]

poda123 wrote:

But I need to make this without using any utility tools, just mere by coding.

Use SymEnumSymbols. It takes a callback function pointer which in turn gets called for every symbol found, as a parameter to the function you get a pointer to a SYMBOL_INFO structure. Use the Flags member of this struct along with SYMFLAG_EXPORT to find out whether this particular symbol is exported or not. I am doing the same in my Process viewer article here -> http://www.codeproject.com/KB/cpp/processviewer.aspx[^] I guess you will have to load the DLL into your process. Not sure!

Nibu thomas Microsoft MVP for VC++ Code must be written to be read, not by the compiler, but by another human being. Programming Blog: http://nibuthomas.wordpress.com

[Stephen Hewitt]

Here's a program I knocked up which lists the functions exported by name from a dll:

// Exports.cpp : Defines the entry point for the console application.
//
 
#include "stdafx.h"
#include <iostream>
#include <windows.h>
#include <Imagehlp.h>
#pragma comment(lib, "Imagehlp.lib")
using namespace std;
 
int main(int argc, char* argv[])
{
if (argc!=2)
{
cerr << "Usage:\n\tExports <path to dll>" << endl;
return 1;
}
 
// Try to map the DLL into memory.
LOADED_IMAGE li;
BOOL bOK = MapAndLoad(
argv[1], // PSTR ImageName
NULL, // PSTR DllPath
&li, // PLOADED_IMAGE LoadedImage
TRUE, // BOOL DotDll
TRUE // BOOL ReadOnly
);
if (!bOK)
{
cerr << "MapAndLoad failed!" << endl;
return 2;
}
 
// Now get the address of the export table.
DWORD expVA = li.FileHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress;
PIMAGE_EXPORT_DIRECTORY pExp = (PIMAGE_EXPORT_DIRECTORY)ImageRvaToVa(
li.FileHeader, // IN PIMAGE_NT_HEADERS NtHeaders
li.MappedAddress, // IN PVOID Base
expVA, // IN ULONG Rva
NULL // IN OUT PIMAGE_SECTION_HEADER *LastRvaSection
);
 
 
// Now dump the functions names.
DWORD rvaNames = pExp->AddressOfNames;
DWORD *prvaNames = (DWORD*)ImageRvaToVa(
li.FileHeader, // IN PIMAGE_NT_HEADERS NtHeaders
li.MappedAddress, // IN PVOID Base
rvaNames, // IN ULONG Rva
NULL // IN OUT PIMAGE_SECTION_HEADER *LastRvaSection
);
for (DWORD i=0; i<pExp->NumberOfNames; ++i)
{
DWORD rvaName = prvaNames[i];
const char *pName = (const char*)ImageRvaToVa(
li.FileHeader, // IN PIMAGE_NT_HEADERS NtHeaders
li.MappedAddress, // IN PVOID Base
rvaName, // IN ULONG Rva
NULL // IN OUT PIMAGE_SECTION_HEADER *LastRvaSection
);
 
cout << pName << endl;
}
 
// Unmap it.
UnMapAndLoad(&li);
 
return 0;
}

Steve

modified on Wednesday, February 13, 2008 10:58 PM

[poda]

The DLL is chosen by the user. Once it is chosen,the names of the exported functions in that DLL has to shown. So it is during runtime the DLL is known, for which its functions are listed out. Thanks!

[poda]

Awesome! Thanks a lot Steve for your help. Thank you so much!

[poda]

Thanks for your reply. I tried to execute the process viewer, but could not run due to the error message "...desktop\procviewer\utils.h(829) : error C2065: 'SLR_NOSEARCH' : undeclared identifier" Could you please help me out to run your application,where I can learn more things out there. Thanks!

[poda]

Could you please share how did you come up with such a nice code to export dll functions. Any website reference? Thanks!

[Nibu babu thomas]

poda123 wrote:

Could you please help me out to run your application,where I can learn more things out there.

Do you have latest platform sdk installed?

Nibu thomas Microsoft MVP for VC++ Code must be written to be read, not by the compiler, but by another human being. Programming Blog: http://nibuthomas.wordpress.com

[Stephen Hewitt]

Many years ago I read this[^] and this[^]. The "WinNT.h" header file is also informative.

Steve

[David Crow]

poda123 wrote:

I tried to execute the process viewer, but could not run due to the error message "...desktop\procviewer\utils.h(829) : error C2065: 'SLR_NOSEARCH' : undeclared identifier"

This makes no sense. C2065 is a compiler error, which means you would not have had a Process Viewer executable.

"Normal is getting dressed in clothes that you buy for work and driving through traffic in a car that you are still paying for, in order to get to the job you need to pay for the clothes and the car and the house you leave vacant all day so you can afford to live in it." - Ellen Goodman

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

[poda]

Hi, I have downloaded and installed the version Microsoft® Windows Server 2003 R2 Platform SDK - March 2006 Edition. But still I get the same error. If there is a newer version,please send me the link. Thanks!