1/*
2 * tclLoadDl.c --
3 *
4 *	This procedure provides a version of the TclLoadFile that works with
5 *	the "dlopen" and "dlsym" library procedures for dynamic loading.
6 *
7 * Copyright (c) 1995-1997 Sun Microsystems, Inc.
8 *
9 * See the file "license.terms" for information on usage and redistribution of
10 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
11 *
12 * RCS: @(#) $Id: tclLoadDl.c,v 1.16 2006/06/13 22:10:19 dkf Exp $
13 */
14
15#include "tclInt.h"
16#ifdef NO_DLFCN_H
17#   include "../compat/dlfcn.h"
18#else
19#   include <dlfcn.h>
20#endif
21
22/*
23 * In some systems, like SunOS 4.1.3, the RTLD_NOW flag isn't defined and this
24 * argument to dlopen must always be 1. The RTLD_GLOBAL flag is needed on some
25 * systems (e.g. SCO and UnixWare) but doesn't exist on others; if it doesn't
26 * exist, set it to 0 so it has no effect.
27 */
28
29#ifndef RTLD_NOW
30#   define RTLD_NOW 1
31#endif
32
33#ifndef RTLD_GLOBAL
34#   define RTLD_GLOBAL 0
35#endif
36
37/*
38 *---------------------------------------------------------------------------
39 *
40 * TclpDlopen --
41 *
42 *	Dynamically loads a binary code file into memory and returns a handle
43 *	to the new code.
44 *
45 * Results:
46 *	A standard Tcl completion code. If an error occurs, an error message
47 *	is left in the interp's result.
48 *
49 * Side effects:
50 *	New code suddenly appears in memory.
51 *
52 *---------------------------------------------------------------------------
53 */
54
55int
56TclpDlopen(
57    Tcl_Interp *interp,		/* Used for error reporting. */
58    Tcl_Obj *pathPtr,		/* Name of the file containing the desired
59				 * code (UTF-8). */
60    Tcl_LoadHandle *loadHandle,	/* Filled with token for dynamically loaded
61				 * file which will be passed back to
62				 * (*unloadProcPtr)() to unload the file. */
63    Tcl_FSUnloadFileProc **unloadProcPtr)
64				/* Filled with address of Tcl_FSUnloadFileProc
65				 * function which should be used for this
66				 * file. */
67{
68    void *handle;
69    CONST char *native;
70
71    /*
72     * First try the full path the user gave us. This is particularly
73     * important if the cwd is inside a vfs, and we are trying to load using a
74     * relative path.
75     */
76
77    native = Tcl_FSGetNativePath(pathPtr);
78    handle = dlopen(native, RTLD_NOW | RTLD_GLOBAL);
79    if (handle == NULL) {
80	/*
81	 * Let the OS loader examine the binary search path for whatever
82	 * string the user gave us which hopefully refers to a file on the
83	 * binary path.
84	 */
85
86	Tcl_DString ds;
87	char *fileName = Tcl_GetString(pathPtr);
88
89	native = Tcl_UtfToExternalDString(NULL, fileName, -1, &ds);
90	handle = dlopen(native, RTLD_NOW | RTLD_GLOBAL);
91	Tcl_DStringFree(&ds);
92    }
93
94    if (handle == NULL) {
95	/*
96	 * Write the string to a variable first to work around a compiler bug
97	 * in the Sun Forte 6 compiler. [Bug 1503729]
98	 */
99
100	const char *errorStr = dlerror();
101
102	Tcl_AppendResult(interp, "couldn't load file \"",
103		Tcl_GetString(pathPtr), "\": ", errorStr, NULL);
104	return TCL_ERROR;
105    }
106
107    *unloadProcPtr = &TclpUnloadFile;
108    *loadHandle = (Tcl_LoadHandle) handle;
109    return TCL_OK;
110}
111
112/*
113 *----------------------------------------------------------------------
114 *
115 * TclpFindSymbol --
116 *
117 *	Looks up a symbol, by name, through a handle associated with a
118 *	previously loaded piece of code (shared library).
119 *
120 * Results:
121 *	Returns a pointer to the function associated with 'symbol' if it is
122 *	found. Otherwise returns NULL and may leave an error message in the
123 *	interp's result.
124 *
125 *----------------------------------------------------------------------
126 */
127
128Tcl_PackageInitProc *
129TclpFindSymbol(
130    Tcl_Interp *interp,		/* Place to put error messages. */
131    Tcl_LoadHandle loadHandle,	/* Value from TcpDlopen(). */
132    CONST char *symbol)		/* Symbol to look up. */
133{
134    CONST char *native;
135    Tcl_DString newName, ds;
136    VOID *handle = (VOID*)loadHandle;
137    Tcl_PackageInitProc *proc;
138
139    /*
140     * Some platforms still add an underscore to the beginning of symbol
141     * names. If we can't find a name without an underscore, try again with
142     * the underscore.
143     */
144
145    native = Tcl_UtfToExternalDString(NULL, symbol, -1, &ds);
146    proc = (Tcl_PackageInitProc *) dlsym(handle,	/* INTL: Native. */
147	    native);
148    if (proc == NULL) {
149	Tcl_DStringInit(&newName);
150	Tcl_DStringAppend(&newName, "_", 1);
151	native = Tcl_DStringAppend(&newName, native, -1);
152	proc = (Tcl_PackageInitProc *) dlsym(handle,	/* INTL: Native. */
153		native);
154	Tcl_DStringFree(&newName);
155    }
156    Tcl_DStringFree(&ds);
157
158    return proc;
159}
160
161/*
162 *----------------------------------------------------------------------
163 *
164 * TclpUnloadFile --
165 *
166 *	Unloads a dynamically loaded binary code file from memory. Code
167 *	pointers in the formerly loaded file are no longer valid after calling
168 *	this function.
169 *
170 * Results:
171 *	None.
172 *
173 * Side effects:
174 *	Code removed from memory.
175 *
176 *----------------------------------------------------------------------
177 */
178
179void
180TclpUnloadFile(
181    Tcl_LoadHandle loadHandle)	/* loadHandle returned by a previous call to
182				 * TclpDlopen(). The loadHandle is a token
183				 * that represents the loaded file. */
184{
185    void *handle;
186
187    handle = (void *) loadHandle;
188    dlclose(handle);
189}
190
191/*
192 *----------------------------------------------------------------------
193 *
194 * TclGuessPackageName --
195 *
196 *	If the "load" command is invoked without providing a package name,
197 *	this procedure is invoked to try to figure it out.
198 *
199 * Results:
200 *	Always returns 0 to indicate that we couldn't figure out a package
201 *	name; generic code will then try to guess the package from the file
202 *	name. A return value of 1 would have meant that we figured out the
203 *	package name and put it in bufPtr.
204 *
205 * Side effects:
206 *	None.
207 *
208 *----------------------------------------------------------------------
209 */
210
211int
212TclGuessPackageName(
213    CONST char *fileName,	/* Name of file containing package (already
214				 * translated to local form if needed). */
215    Tcl_DString *bufPtr)	/* Initialized empty dstring. Append package
216				 * name to this if possible. */
217{
218    return 0;
219}
220
221/*
222 * Local Variables:
223 * mode: c
224 * c-basic-offset: 4
225 * fill-column: 78
226 * End:
227 */
228