/* 

  * 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;

 }