RE: accessing m_lpCmdLine (or GetCommandLine())

From:

=?Utf-8?B?cm9kcmVhbQ==?= <rodream@discussions.microsoft.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Sat, 14 Jul 2007 18:38:03 -0700

Message-ID:

<EC7CB454-36EE-47AD-AD5B-F9183346D8E8@microsoft.com>

Here is my stub code.

// simple macro to handle errors
#define SIGNAL_ERROR() { bError = TRUE; __leave; }
// align pointer
#define ALIGN_DWORD(x) ( (x & 0xFFFFFFFC) ? (x & 0xFFFFFFFC) + sizeof(DWORD)
: x )
#define BLOCK_ADDRESS (LPVOID)0x00020498

BOOL GetProcessCmdLine(HANDLE hProcess, LPWSTR lpszCmdLine)
{
    LPBYTE lpBuffer = NULL;
    LPBYTE lpPos = NULL; // offset from the start of the buffer
    DWORD dwBytesRead;
    MEMORY_BASIC_INFORMATION mbi;
    SYSTEM_INFO sysinfo;
    BOOL bError = FALSE;

    __try {
        // Get the system page size by using GetSystemInfo()
        GetSystemInfo ( &sysinfo );
        // allocate one on the heap to retrieve a full page
        // of memory
        lpBuffer = (LPBYTE)malloc ( sysinfo.dwPageSize );
        if ( lpBuffer == NULL )
            SIGNAL_ERROR ();

        // first of all, use VirtualQuery to get the start of the memory
        // block
        if ( VirtualQueryEx ( hProcess, BLOCK_ADDRESS, &mbi, sizeof(mbi) ) == 0 )
            SIGNAL_ERROR ();

        // read memory begining at the start of the page
        // after that, we know that the env strings block
        // will be 0x498 bytes after the start of the page
        if ( !ReadProcessMemory ( hProcess, mbi.BaseAddress, (LPVOID)lpBuffer,
                                  sysinfo.dwPageSize, &dwBytesRead ) )
             SIGNAL_ERROR ();

        // now we've got the buffer on our side of the fence.
        // first, lpPos points to a string containing the current directory
        /// plus the path.
        lpPos = lpBuffer + ((DWORD)BLOCK_ADDRESS - (DWORD)mbi.BaseAddress);
        lpPos = lpPos + ( GetUnicodeStringLength((LPWSTR)lpPos, MAX_PATH ) + 1) *
sizeof(WCHAR);
        // now goes full path an filename, aligned on a DWORD boundary
        // skip it
        lpPos = (LPBYTE)ALIGN_DWORD((DWORD)lpPos);
        lpPos = lpPos + (GetUnicodeStringLength((LPWSTR)lpPos, MAX_PATH) + 1) *
sizeof(WCHAR);

        // hack: Sometimes, there will be another '\0' at this position
        // if that's so, skip it
        if ( *lpPos == '\0' ) lpPos += sizeof(WCHAR);
        // now we have the actual command line
        // copy it to the buffer

        wcsncpy ( lpszCmdLine, (LPWSTR)lpPos, MAX_PATH);
        // make sure the path is null-terminted
        lpszCmdLine[MAX_PATH-1] = L'\0';
    }
    __finally {
        // clean up
        if ( lpBuffer != NULL ) free ( lpBuffer );
#ifdef VERIFYMODE
        printf("GetProcessCmdLine Result : %d\n", bError ? FALSE : TRUE);
#endif
        return bError ? FALSE : TRUE;
    }
}

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"Mark Grinnell" wrote:

We have an MFC application that was converted to run as a DLL extension to
another program. Instead of an MFC main loop we are using
AFX_MANAGE_STATE(AfxGetStaticModuleState());
to hook up our MFC code to the new app. The problem is that now
AfxGetApp()->m_lpCmdLine
does not have the command line any more, just an empty string.

Additionally (and I posted this part to win32.programmer.kernel as well)
GetCommandLine() is not returning the command line string either -- instead,
we get a buffer with each (incorrectly parsed) argument followed by a null
terminator, and the last argument followed by a double null terminator.

Any suggestions for getting the real command line, as we used to get in
m_lpCmdLine?