/* 

 * tclLoadDl.c --

 *

 *	This procedure provides a version of the TclLoadFile that

 *	works with the "dlopen" and "dlsym" library procedures for

 *	dynamic loading.

 *

 * Copyright (c) 1995-1997 Sun Microsystems, Inc.

 *

 * See the file "license.terms" for information on usage and redistribution

 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.

 *

 * RCS: @(#) $Id: tclLoadDl.c,v 1.13.2.1 2006/06/13 22:54:01 dkf Exp $

 */

#include "tclInt.h"

#ifdef NO_DLFCN_H

#   include "../compat/dlfcn.h"

#else

#   include <dlfcn.h>

#endif

/*

 * In some systems, like SunOS 4.1.3, the RTLD_NOW flag isn't defined

 * and this argument to dlopen must always be 1.  The RTLD_GLOBAL

 * flag is needed on some systems (e.g. SCO and UnixWare) but doesn't

 * exist on others;  if it doesn't exist, set it to 0 so it has no effect.

 */

#ifndef RTLD_NOW

#   define RTLD_NOW 1

#endif

#ifndef RTLD_GLOBAL

#   define RTLD_GLOBAL 0

#endif

/*

 *---------------------------------------------------------------------------

 *

 * TclpDlopen --

 *

 *	Dynamically loads a binary code file into memory and returns

 *	a handle to the new code.

 *

 * Results:

 *	A standard Tcl completion code.  If an error occurs, an error

 *	message is left in the interp's result. 

 *

 * Side effects:

 *	New code suddenly appears in memory.

 *

 *---------------------------------------------------------------------------

 */

int

TclpDlopen(interp, pathPtr, loadHandle, unloadProcPtr)

    Tcl_Interp *interp;		/* Used for error reporting. */

    Tcl_Obj *pathPtr;		/* Name of the file containing the desired

				 * code (UTF-8). */

    Tcl_LoadHandle *loadHandle;	/* Filled with token for dynamically loaded

				 * file which will be passed back to 

				 * (*unloadProcPtr)() to unload the file. */

    Tcl_FSUnloadFileProc **unloadProcPtr;	

				/* Filled with address of Tcl_FSUnloadFileProc

				 * function which should be used for

				 * this file. */

{

    VOID *handle;

    CONST char *native;

    /* 

     * First try the full path the user gave us.  This is particularly

     * important if the cwd is inside a vfs, and we are trying to load

     * using a relative path.

     */

    native = Tcl_FSGetNativePath(pathPtr);

    handle = dlopen(native, RTLD_NOW | RTLD_GLOBAL);

    if (handle == NULL) {

	/* 

	 * Let the OS loader examine the binary search path for

	 * whatever string the user gave us which hopefully refers

	 * to a file on the binary path

	 */

	Tcl_DString ds;

	char *fileName = Tcl_GetString(pathPtr);

	native = Tcl_UtfToExternalDString(NULL, fileName, -1, &ds);

	handle = dlopen(native, RTLD_NOW | RTLD_GLOBAL);

	Tcl_DStringFree(&ds);

    }

    if (handle == NULL) {

	/*

	 * Write the string to a variable first to work around a compiler bug

	 * in the Sun Forte 6 compiler. [Bug 1503729]

	 */

	CONST char *errorStr = dlerror();

	Tcl_AppendResult(interp, "couldn't load file \"", 

		Tcl_GetString(pathPtr), "\": ", errorStr, (char *) NULL);

	return TCL_ERROR;

    }

    *unloadProcPtr = &TclpUnloadFile;

    *loadHandle = (Tcl_LoadHandle)handle;

    return TCL_OK;

}

/*

 *----------------------------------------------------------------------

 *

 * TclpFindSymbol --

 *

 *	Looks up a symbol, by name, through a handle associated with

 *	a previously loaded piece of code (shared library).

 *

 * Results:

 *	Returns a pointer to the function associated with 'symbol' if

 *	it is found.  Otherwise returns NULL and may leave an error

 *	message in the interp's result.

 *

 *----------------------------------------------------------------------

 */

Tcl_PackageInitProc*

TclpFindSymbol(interp, loadHandle, symbol) 

    Tcl_Interp *interp;

    Tcl_LoadHandle loadHandle;

    CONST char *symbol;

{

    CONST char *native;

    Tcl_DString newName, ds;

    VOID *handle = (VOID*)loadHandle;

    Tcl_PackageInitProc *proc;

    /* 

     * Some platforms still add an underscore to the beginning of symbol

     * names.  If we can't find a name without an underscore, try again

     * with the underscore.

     */

    native = Tcl_UtfToExternalDString(NULL, symbol, -1, &ds);

    proc = (Tcl_PackageInitProc *) dlsym(handle,	/* INTL: Native. */

	    native);	

    if (proc == NULL) {

	Tcl_DStringInit(&newName);

	Tcl_DStringAppend(&newName, "_", 1);

	native = Tcl_DStringAppend(&newName, native, -1);

	proc = (Tcl_PackageInitProc *) dlsym(handle, /* INTL: Native. */

		native);

	Tcl_DStringFree(&newName);

    }

    Tcl_DStringFree(&ds);

    return proc;

}

/*

 *----------------------------------------------------------------------

 *

 * TclpUnloadFile --

 *

 *	Unloads a dynamically loaded binary code file from memory.

 *	Code pointers in the formerly loaded file are no longer valid

 *	after calling this function.

 *

 * Results:

 *	None.

 *

 * Side effects:

 *	Code removed from memory.

 *

 *----------------------------------------------------------------------

 */

void

TclpUnloadFile(loadHandle)

    Tcl_LoadHandle loadHandle;	/* loadHandle returned by a previous call

				 * to TclpDlopen().  The loadHandle is 

				 * a token that represents the loaded 

				 * file. */

{

    VOID *handle;

    handle = (VOID *) loadHandle;

    dlclose(handle);

}

/*

 *----------------------------------------------------------------------

 *

 * TclGuessPackageName --

 *

 *	If the "load" command is invoked without providing a package

 *	name, this procedure is invoked to try to figure it out.

 *

 * Results:

 *	Always returns 0 to indicate that we couldn't figure out a

 *	package name;  generic code will then try to guess the package

 *	from the file name.  A return value of 1 would have meant that

 *	we figured out the package name and put it in bufPtr.

 *

 * Side effects:

 *	None.

 *

 *----------------------------------------------------------------------

 */

int

TclGuessPackageName(fileName, bufPtr)

    CONST char *fileName;	/* Name of file containing package (already

				 * translated to local form if needed). */

    Tcl_DString *bufPtr;	/* Initialized empty dstring.  Append

				 * package name to this if possible. */

{

    return 0;

}