/* 

 * tclLoadShl.c --

 *

 *	This procedure provides a version of the TclLoadFile that works

 *	with the "shl_load" and "shl_findsym" library procedures for

 *	dynamic loading (e.g. for HP machines).

 *

 * 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: tclLoadShl.c,v 1.13.2.1 2005/10/05 04:23:56 hobbs Exp $

 */

#include <dl.h>

/*

 * On some HP machines, dl.h defines EXTERN; remove that definition.

 */

#ifdef EXTERN

#   undef EXTERN

#endif

#include "tclInt.h"

/*

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

 *

 * 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. */

{

    shl_t handle;

    CONST char *native;

    char *fileName = Tcl_GetString(pathPtr);

    /*

     * The flags below used to be BIND_IMMEDIATE; they were changed at

     * the suggestion of Wolfgang Kechel (wolfgang@prs.de): "This

     * enables verbosity for missing symbols when loading a shared lib

     * and allows to load libtk8.0.sl into tclsh8.0 without problems.

     * In general, this delays resolving symbols until they are actually

     * needed.  Shared libs do no longer need all libraries linked in

     * when they are build."

     */

    /*

     * 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 = shl_load(native, BIND_DEFERRED|BIND_VERBOSE, 0L);

    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;

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

	handle = shl_load(native,

			  BIND_DEFERRED|BIND_VERBOSE|DYNAMIC_PATH, 0L);

	Tcl_DStringFree(&ds);

    }

    if (handle == NULL) {

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

		"\": ", Tcl_PosixError(interp), (char *) NULL);

	return TCL_ERROR;

    }

    *loadHandle = (Tcl_LoadHandle) handle;

    *unloadProcPtr = &TclpUnloadFile;

    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;

{

    Tcl_DString newName;

    Tcl_PackageInitProc *proc=NULL;

    shl_t handle = (shl_t)loadHandle;

    /*

     * Some versions of the HP system software still use "_" at the

     * beginning of exported symbols while others don't;  try both

     * forms of each name.

     */

    if (shl_findsym(&handle, symbol, (short) TYPE_PROCEDURE, (void *) &proc)

	    != 0) {

	Tcl_DStringInit(&newName);

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

	Tcl_DStringAppend(&newName, symbol, -1);

	if (shl_findsym(&handle, Tcl_DStringValue(&newName),

		(short) TYPE_PROCEDURE, (void *) &proc) != 0) {

	    proc = NULL;

	}

	Tcl_DStringFree(&newName);

    }

    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. */

{

    shl_t handle;

    handle = (shl_t) loadHandle;

    shl_unload(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;

}