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pTk/mTk/tclWin/tclWinPipe.c  view on Meta::CPAN

    /* Look for the program as an external program.  First try the name
     * as it is, then try adding .com, .exe, and .bat, in that order, to
     * the name, looking for an executable.
     *
     * Using the raw SearchPath() procedure doesn't do quite what is
     * necessary.  If the name of the executable already contains a '.'
     * character, it will not try appending the specified extension when
     * searching (in other words, SearchPath will not find the program
     * "a.b.exe" if the arguments specified "a.b" and ".exe").
     * So, first look for the file as it is named.  Then manually append
     * the extensions, looking for a match.
     */

    applType = APPL_NONE;
    Tcl_DStringInit(&nameBuf);
    Tcl_DStringAppend(&nameBuf, originalName, -1);
    nameLen = Tcl_DStringLength(&nameBuf);

    for (i = 0; i < (int) (sizeof(extensions) / sizeof(extensions[0])); i++) {
	Tcl_DStringSetLength(&nameBuf, nameLen);
	Tcl_DStringAppend(&nameBuf, extensions[i], -1);
        nativeName = Tcl_WinUtfToTChar(Tcl_DStringValue(&nameBuf),
		Tcl_DStringLength(&nameBuf), &ds);
	found = (*tclWinProcs->searchPathProc)(NULL, nativeName, NULL,
		MAX_PATH, nativeFullPath, &rest);
	Tcl_DStringFree(&ds);
	if (found == 0) {
	    continue;
	}

	/*
	 * Ignore matches on directories or data files, return if identified
	 * a known type.
	 */

	attr = (*tclWinProcs->getFileAttributesProc)((TCHAR *) nativeFullPath);
	if ((attr == 0xffffffff) || (attr & FILE_ATTRIBUTE_DIRECTORY)) {
	    continue;
	}
	strcpy(fullName, Tcl_WinTCharToUtf((TCHAR *) nativeFullPath, -1, &ds));
	Tcl_DStringFree(&ds);

	ext = strrchr(fullName, '.');
	if ((ext != NULL) && (stricmp(ext, ".bat") == 0)) {
	    applType = APPL_DOS;
	    break;
	}

	hFile = (*tclWinProcs->createFileProc)((TCHAR *) nativeFullPath,
		GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING,
		FILE_ATTRIBUTE_NORMAL, NULL);
	if (hFile == INVALID_HANDLE_VALUE) {
	    continue;
	}

	header.e_magic = 0;
	ReadFile(hFile, (void *) &header, sizeof(header), &read, NULL);
	if (header.e_magic != IMAGE_DOS_SIGNATURE) {
	    /*
	     * Doesn't have the magic number for relocatable executables.  If
	     * filename ends with .com, assume it's a DOS application anyhow.
	     * Note that we didn't make this assumption at first, because some
	     * supposed .com files are really 32-bit executables with all the
	     * magic numbers and everything.
	     */

	    CloseHandle(hFile);
	    if ((ext != NULL) && (stricmp(ext, ".com") == 0)) {
		applType = APPL_DOS;
		break;
	    }
	    continue;
	}
	if (header.e_lfarlc != sizeof(header)) {
	    /*
	     * All Windows 3.X and Win32 and some DOS programs have this value
	     * set here.  If it doesn't, assume that since it already had the
	     * other magic number it was a DOS application.
	     */

	    CloseHandle(hFile);
	    applType = APPL_DOS;
	    break;
	}

	/*
	 * The DWORD at header.e_lfanew points to yet another magic number.
	 */

	buf[0] = '\0';
	SetFilePointer(hFile, header.e_lfanew, NULL, FILE_BEGIN);
	ReadFile(hFile, (void *) buf, 2, &read, NULL);
	CloseHandle(hFile);

	if ((buf[0] == 'N') && (buf[1] == 'E')) {
	    applType = APPL_WIN3X;
	} else if ((buf[0] == 'P') && (buf[1] == 'E')) {
	    applType = APPL_WIN32;
	} else {
	    /*
	     * Strictly speaking, there should be a test that there
	     * is an 'L' and 'E' at buf[0..1], to identify the type as
	     * DOS, but of course we ran into a DOS executable that
	     * _doesn't_ have the magic number -- specifically, one
	     * compiled using the Lahey Fortran90 compiler.
	     */

	    applType = APPL_DOS;
	}
	break;
    }
    Tcl_DStringFree(&nameBuf);

    if (applType == APPL_NONE) {
	TclWinConvertError(GetLastError());
	Tcl_AppendResult(interp, "couldn't execute \"", originalName,
		"\": ", Tcl_PosixError(interp), (char *) NULL);
	return APPL_NONE;
    }