1. xemacs
  2. XEmacs

Source

XEmacs / src / emodules.c

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
/* emodules.c - Support routines for dynamic module loading
(C) Copyright 1998, 1999 J. Kean Johnston. All rights reserved.

This file is part of XEmacs.

XEmacs is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.

XEmacs is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with XEmacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include "emodules.h"
#include "sysdll.h"

#ifdef HAVE_SHLIB

/* CE-Emacs version number */
Lisp_Object Vmodule_version;

/* Do we do our work quietly? */
int load_modules_quietly;

/* Load path */
Lisp_Object Vmodule_load_path;

typedef struct _emodules_list
{
  int used;             /* Is this slot used?                           */
  char *soname;         /* Name of the shared object loaded (full path) */
  char *modname;        /* The name of the module                       */
  char *modver;         /* The version that the module is at            */
  char *modtitle;       /* How the module announces itself              */
  dll_handle dlhandle;  /* Dynamic lib handle                           */
} emodules_list;

static Lisp_Object Vmodule_extensions;

static int emodules_depth;
static dll_handle dlhandle;
static emodules_list *modules;
static int modnum;

static int find_make_module (CONST char *mod, CONST char *name, CONST char *ver, int make_or_find);
static Lisp_Object module_load_unwind (Lisp_Object);
static void attempt_module_delete (int mod);

DEFUN ("load-module", Fload_module, 1, 3, "FLoad dynamic module: ", /*
Load in a C Emacs Extension module named FILE.
The optional NAME and VERSION are used to identify specific modules.

This function is similar in intent to `load' except that it loads in
pre-compiled C or C++ code, using dynamic shared objects.  If NAME is
specified, then the module is only loaded if its internal name matches
the NAME specified.  If VERSION is specified, then the module is only
loaded if it matches that VERSION.  This function will check to make
sure that the same module is not loaded twice.  Modules are searched
for in the same way as Lisp files, except that the valid file
extensions are `.so', `.dll' or `.ell'.

All symbols in the shared module must be completely resolved in order
for this function to be successful.  Any modules which the specified
FILE depends on will be automatically loaded.  You can determine which
modules have been loaded as dynamic shared objects by examining the
return value of the function `list-modules'.

It is possible, although unwise, to unload modules using `unload-module'.
The prefered mechanism for unloading or reloading modules is to quit
XEmacs, and then reload those new or changed modules that are required.

Messages informing you of the progress of the load are displayed unless
the variable `load-modules-quietly' is non-NIL.
*/
       (file,name,version))
{
  char *mod, *mname, *mver;
  int speccount = specpdl_depth();

  CHECK_STRING(file);

  mod = (char *)XSTRING_DATA (file);

  if (NILP (name))
    mname = "";
  else
    mname = (char *)XSTRING_DATA (name);

  if (NILP (version))
    mver = "";
  else
    mver = (char *)XSTRING_DATA (version);

  dlhandle = 0;
  record_unwind_protect (module_load_unwind, make_int(modnum));
  emodules_load (mod, mname, mver);
  unbind_to (speccount, Qnil);

  return Qt;
}

#ifdef DANGEROUS_NASTY_SCARY_MONSTER

DEFUN ("unload-module", Fmodule_unload, 1, 3, 0, /*
Unload a module previously loaded with load-module.

As with load-module, this function requires at least the module FILE, and
optionally the module NAME and VERSION to unload.  It may not be possible
for the module to be unloaded from memory, as there may be Lisp objects
refering to variables inside the module code.  However, once you have
requested a module to be unloaded, it will be unloaded from memory as
soon as the last reference to symbols within the module is destroyed.
*/
       (file,name,version))
{
  int x;
  char *mod, *mname, *mver;

  CHECK_STRING(file);

  mod = (char *)XSTRING_DATA (file);

  if (NILP (name))
    mname = "";
  else
    mname = (char *)XSTRING_DATA (name);

  if (NILP (version))
    mver = "";
  else
    mver = (char *)XSTRING_DATA (version);

  x = find_make_module (mod, mname, mver, 1);
  if (x != -1)
    attempt_module_delete (x);
  return Qt;
}
#endif /* DANGEROUS_NASTY_SCARY_MONSTER */

DEFUN ("list-modules", Flist_modules, 0, 0, "", /*
Produce a list of loaded dynamic modules.

This function will return a list of all the loaded dynamic modules.
Each element in the list is a list in the form (SONAME NAME VER DESC),
where SONAME is the name of the shared object that was loaded, NAME
is the internal module name, VER is the version of the module, and DESC
is how the module describes itself.

This function returns a list, so you will need to assign the return value
to a variable and then examine the variable with `describe-variable'.
For example:

  (setq mylist (list-modules))
  (describe-variable 'mylist)


NOTE: It is possible for the same module to be loaded more than once,
at different versions.  However, you should never see the same module,
with the same name and version, loaded more than once.  If you do, this
is a bug, and you are encouraged to report it.
*/
       ())
{
  Lisp_Object mlist = Qnil;
  int i;

  for (i = 0; i < modnum; i++)
    {
      if (modules[i].used == 1)
        mlist = Fcons (list4 (build_string (modules[i].soname),
                              build_string (modules[i].modname),
                              build_string (modules[i].modver),
                              build_string (modules[i].modtitle)), mlist);
    }

  return mlist;
}

static int
find_make_module (CONST char *mod, CONST char *name, CONST char *ver, int mof)
{
  int i, fs = -1;

  for (i = 0; i < modnum; i++)
    {
      if (fs == -1 && modules[i].used == 0)
        fs = i;
      if (strcmp (modules[i].soname, mod) == 0)
        {
          if (name && name[0] && strcmp (modules[i].modname, name))
            continue;
          if (ver && ver[0] && strcmp (modules[i].modver, ver))
            continue;
          return i; /* Found a match */
        }
    }

  if (mof)
    return fs;

  if (fs != -1)
    return fs; /* First free slot */

  /*
   * We only get here if we havent found a free slot and the module was
   * not previously loaded.
   */
  if (modules == (emodules_list *)0)
    modules = (emodules_list *)xmalloc (sizeof(emodules_list));
  modnum++;
  modules = (emodules_list *) xrealloc (modules, modnum * sizeof(emodules_list));

  fs = modnum - 1;
  memset (&modules[fs], 0, sizeof(emodules_list));
  return fs;
}

static void
attempt_module_delete (int mod)
{
  if (dll_close (modules[mod].dlhandle) == 0)
    {
      xfree (modules[mod].soname);
      xfree (modules[mod].modname);
      xfree (modules[mod].modver);
      xfree (modules[mod].modtitle);
      modules[mod].dlhandle = 0;
      modules[mod].used = 0;
    }
  else if (modules[mod].used > 1)
    modules[mod].used = 1; /* We couldn't delete it - it stays */
}

static Lisp_Object
module_load_unwind (Lisp_Object upto)
{
  int x,l=0;

  /*
   * First close off the current handle if it is open.
   */
  if (dlhandle != 0)
    dll_close (dlhandle);
  dlhandle = 0;

  if (CONSP (upto))
    {
      if (INTP (XCAR (upto)))
        l = XINT (XCAR (upto));
      free_cons (XCONS (upto));
    }
  else
    l = XINT (upto);

  /*
   * Here we need to go through and dlclose() (IN REVERSE ORDER!) any
   * modules that were loaded as part of this load chain. We only mark
   * the slots as closed if the dlclose() succeeds.
   */
  for (x = modnum-1; x >= l; x--)
    {
      if (modules[x].used > 1)
        attempt_module_delete (x);
    }
  emodules_depth = 0;

  return Qnil;
}

/*
 * Do the actual grunt-work of loading in a module. We first try and
 * dlopen() the module. If that fails, we have an error and we bail
 * out immediately. If the dlopen() succeeds, we need to check for the
 * existance of certain special symbols.
 *
 * All modules will have complete access to the variables and functions
 * defined within XEmacs itself.  It is up to the module to declare any
 * variables or functions it uses, however.  Modules will also have access
 * to other functions and variables in other loaded modules, unless they
 * are defined as STATIC.
 *
 * We need to be very careful with how we load modules. If we encounter an
 * error along the way, we need to back out completely to the point at
 * which the user started. Since we can be called resursively, we need to
 * take care with marking modules as loaded. When we first start loading
 * modules, we set the counter to zero. As we enter the function each time,
 * we incremement the counter, and before we leave we decrement it. When
 * we get back down to 0, we know we are at the end of the chain and we
 * can mark all the modules in the list as loaded.
 *
 * When we signal an error, we need to be sure to unwind all modules loaded
 * thus far (but only for this module chain). It is assumed that if any
 * modules in a chain fail, then they all do. This is logical, considering
 * that the only time we recurse is when we have dependant modules. So in
 * the error handler we take great care to close off the module chain before
 * we call "error" and let the Fmodule_load unwind_protect() function handle
 * the cleaning up.
 */
void
emodules_load(CONST char *module, CONST char *modname, CONST char *modver)
{
  Lisp_Object filename;
  Lisp_Object foundname;
  int fd, x, mpx;
  char *soname, *tmod;
  CONST char **f;
  CONST long *ellcc_rev;
  char *mver, *mname, *mtitle, *symname;
  void (*modload)(void) = 0;
  void (*modsyms)(void) = 0;
  void (*modvars)(void) = 0;
  void (*moddocs)(void) = 0;
  emodules_list *mp;
  struct gcpro gcpro1,gcpro2;

  filename = Qnil;
  foundname = Qnil;

  emodules_depth++;
  dlhandle = 0;

  if ((module == (CONST char *)0) || (module[0] == '\0'))
    error ("Empty module name");

  /* This is to get around the fact that build_string() is not declared
     as taking a const char * as an argument. I HATE compiler warnings. */
  tmod = (char *)alloca (strlen (module) + 1);
  strcpy (tmod, module);

  GCPRO2(filename, foundname);
  filename = build_string (tmod);
  fd = locate_file(Vmodule_load_path, filename, Vmodule_extensions,
		   &foundname, -1);
  UNGCPRO;

  if (fd < 0)
    signal_simple_error ("Cannot open dynamic module", filename);

  soname = (char *)alloca (XSTRING_LENGTH (foundname) + 1);
  strcpy (soname, (char *)XSTRING_DATA (foundname));

  dlhandle = dll_open (soname);
  if (dlhandle == (dll_handle)0)
    error ("Opening dynamic module: %s", dll_error (dlhandle));

  ellcc_rev = (CONST long *)dll_variable (dlhandle, "emodule_compiler");
  if ((ellcc_rev == (CONST long *)0) || (*ellcc_rev <= 0))
    error ("Missing symbol `emodule_compiler': Invalid dynamic module");
  if (*ellcc_rev > EMODULES_REVISION)
    error ("Unsupported version `%ld(%ld)': Invalid dynamic module",
           *ellcc_rev, EMODULES_REVISION);

  f = (CONST char **)dll_variable (dlhandle, "emodule_name");
  if ((f == (CONST char **)0) || (*f == (CONST char *)0))
    error ("Missing symbol `emodule_name': Invalid dynamic module");

  mname = (char *)alloca (strlen (*f) + 1);
  strcpy (mname, *f);
  if (mname[0] == '\0')
    error ("Empty value for `emodule_name': Invalid dynamic module");

  f = (CONST char **)dll_variable (dlhandle, "emodule_version");
  if ((f == (CONST char **)0) || (*f == (CONST char *)0))
    error ("Missing symbol `emodule_version': Invalid dynamic module");

  mver = (char *)alloca (strlen (*f) + 1);
  strcpy (mver, *f);

  f = (CONST char **)dll_variable (dlhandle, "emodule_title");
  if ((f == (CONST char **)0) || (*f == (CONST char *)0))
    error ("Missing symbol `emodule_title': Invalid dynamic module");

  mtitle = (char *)alloca (strlen (*f) + 1);
  strcpy (mtitle, *f);

  symname = (char *)alloca (strlen (mname) + 15);

  strcpy (symname, "modules_of_");
  strcat (symname, mname);
  modload = (void (*)(void))dll_function (dlhandle, symname);
  /*
   * modload is optional. If the module doesnt require other modules it can
   * be left out.
   */

  strcpy (symname, "syms_of_");
  strcat (symname, mname);
  modsyms = (void (*)(void))dll_function (dlhandle, symname);
  if (modsyms == (void (*)(void))0)
    error ("Missing symbol `%s': Invalid dynamic module", symname);

  strcpy (symname, "vars_of_");
  strcat (symname, mname);
  modvars = (void (*)(void))dll_function (dlhandle, symname);
  if (modvars == (void (*)(void))0)
    error ("Missing symbol `%s': Invalid dynamic module", symname);

  strcpy (symname, "docs_of_");
  strcat (symname, mname);
  moddocs = (void (*)(void))dll_function (dlhandle, symname);
  if (moddocs == (void (*)(void))0)
    error ("Missing symbol `%s': Invalid dynamic module", symname);

  if (modname && modname[0] && strcmp (modname, mname))
    error ("Module name mismatch");

  if (modver && modver[0] && strcmp (modver, mver))
    error ("Module version mismatch");

  /*
   * Attempt to make a new slot for this module. If this really is the
   * first time we are loading this module, the used member will be 0.
   * If that is non-zero, we know that we have a previously loaded module
   * of the same name and version, and we dont need to go any further.
   */
  mpx = find_make_module (soname, mname, mver, 0);
  mp = &modules[mpx];
  if (mp->used > 0)
    {
      emodules_depth--;
      dll_close (dlhandle);
      return;
    }

  if (!load_modules_quietly)
    message ("Loading %s v%s (%s)", mname, mver, mtitle);

  /*
   * We have passed the basic initialization, and can now add this
   * module to the list of modules.
   */
  mp->used = emodules_depth + 1;
  mp->soname = xstrdup (soname);
  mp->modname = xstrdup (mname);
  mp->modver = xstrdup (mver);
  mp->modtitle = xstrdup (mtitle);
  mp->dlhandle = dlhandle;
  dlhandle = 0;

  /*
   * Now we need to call the module init function and perform the various
   * startup tasks.
   */
  if (modload != 0)
    (*modload)();

  /*
   * Now we can get the module to initialize its symbols, and then its
   * variables, and lastly the documentation strings.
   */
  (*modsyms)();
  (*modvars)();
  (*moddocs)();

  if (!load_modules_quietly)
    message ("Loaded module %s v%s (%s)", mname, mver, mtitle);


  emodules_depth--;
  if (emodules_depth == 0)
    {
      /*
       * We have reached the end of the load chain. We now go through the
       * list of loaded modules and mark all the valid modules as just
       * that.
       */
      for (x = 0; x < modnum; x++)
        if (modules[x].used > 1)
          modules[x].used = 1;
    }
}

void
emodules_doc_subr(CONST char *symname, CONST char *doc)
{
  Bytecount len = strlen (symname);
  Lisp_Object sym = oblookup (Vobarray, (CONST Bufbyte *)symname, len);
  struct Lisp_Subr *subr;

  if (SYMBOLP(sym))
    {
      subr = XSUBR( XSYMBOL(sym)->function);
      subr->doc = xstrdup (doc);
    }
  /*
   * FIXME: I wish there was some way to avoid the xstrdup(). Is it
   * possible to just set a pointer to the string, or somehow create a
   * symbol whose value we can point to the constant string? Can someone
   * look into this?
   */
}

void
emodules_doc_sym (CONST char *symname, CONST char *doc)
{
  Bytecount len = strlen (symname);
  Lisp_Object sym = oblookup (Vobarray, (CONST Bufbyte *)symname, len);
  Lisp_Object docstr;
  struct gcpro gcpro1;

  if (SYMBOLP(sym))
    {
      docstr = build_string (doc);
      GCPRO1(docstr);
      Fput (sym, Qvariable_documentation, docstr);
      UNGCPRO;
    }
}


void
syms_of_module (void)
{
  DEFSUBR(Fload_module);
  DEFSUBR(Flist_modules);
#ifdef DANGEROUS_NASTY_SCARY_MONSTER
  DEFSUBR(Funload_module);
#endif
}

void
reinit_vars_of_module (void)
{
  emodules_depth = 0;
  modules = (emodules_list *)0;
  modnum = 0;
}

void
vars_of_module (void)
{
  reinit_vars_of_module ();

  DEFVAR_LISP ("module-version", &Vmodule_version /*
Emacs dynamic loading mechanism version, as a string.

This string is in the form XX.YY.ppp, where XX is the major version
number, YY is the minor version number, and ppp is the patch level.
This variable can be used to distinquish between different versions of
the dynamic loading technology used in Emacs, if required.  It is not
a given that this value will be the same as the Emacs version number.
*/ );
  Vmodule_version = build_string (EMODULES_VERSION);

  DEFVAR_BOOL ("load-modules-quietly", &load_modules_quietly /*
*Set to t if module loading is to be silent.

Normally, when loading dynamic modules, Emacs will inform you of its
progress, and will display the module name and version if the module
is loaded correctly.  Setting this variable to `t' will suppress these
messages.  This would normally only be done if `load-module' was being
called by a Lisp function.
*/);

  DEFVAR_LISP ("module-load-path", &Vmodule_load_path /*
*List of directories to search for dynamic modules to load.
Each element is a string (directory name) or nil (try default directory).

Note that elements of this list *may not* begin with "~", so you must
call `expland-file-name' on them before adding them to this list.

Initialized based on EMACSMODULEPATH environment variable, if any, otherwise
to default specified the file `paths.h' when XEmacs was built.  If there
were no paths specified in `paths.h', then XEmacs chooses a default
value for this variable by looking around in the file-system near the
directory in which the XEmacs executable resides.

Due to the nature of dynamic modules, the path names should almost always
refer to architecture-dependant directories.  It is unwise to attempt to
store dynamic modules in a hetrogenous environment.  Some environments
are similar enough to each other that XEmacs will be unable to determine
the correctness of a dynamic module, which can have unpredictable results
when a dynamic module is loaded.
*/);

  /* #### Export this to Lisp */
  Vmodule_extensions = build_string (":.ell:.so:.dll");
  staticpro (&Vmodule_extensions);

  load_modules_quietly = 0;
  Vmodule_load_path = Qnil;
  Fprovide (intern ("modules"));
}

#endif /* HAVE_SHLIB */