src/mapi/glapi/glapi_getproc.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25 /**
  26  * \file glapi_getproc.c
  27  *
  28  * Code for implementing glXGetProcAddress(), etc.
  29  * This was originally in glapi.c but refactored out.
  30  */
  31
  32
  33 #include <assert.h>
  34 #include <string.h>
  35 #include <stdlib.h>
  36 #include "glapi/glapi_priv.h"
  37 #include "glapi/glapitable.h"
  38
  39
  40 #define FIRST_DYNAMIC_OFFSET (sizeof(struct _glapi_table) / sizeof(void *))
  41
  42
  43
  44 /**********************************************************************
  45  * Static function management.
  46  */
  47
  48
  49 #if !defined(DISPATCH_FUNCTION_SIZE)
  50 # define NEED_FUNCTION_POINTER
  51 #endif
  52 #include "glapi/glprocs.h"
  53
  54
  55 /**
  56  * Search the table of static entrypoint functions for the named function
  57  * and return the corresponding glprocs_table_t entry.
  58  */
  59 static const glprocs_table_t *
  60 get_static_proc( const char * n )
  61 {
  62    GLuint i;
  63    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
  64       const char *testName = gl_string_table + static_functions[i].Name_offset;
  65       if (strcmp(testName, n) == 0)
  66       {
  67          return &static_functions[i];
  68       }
  69    }
  70    return NULL;
  71 }
  72
  73
  74 /**
  75  * Return dispatch table offset of the named static (built-in) function.
  76  * Return -1 if function not found.
  77  */
  78 static GLint
  79 get_static_proc_offset(const char *funcName)
  80 {
  81    const glprocs_table_t * const f = get_static_proc( funcName );
  82    if (f == NULL) {
  83       return -1;
  84    }
  85
  86    return f->Offset;
  87 }
  88
  89
  90
  91 /**
  92  * Return dispatch function address for the named static (built-in) function.
  93  * Return NULL if function not found.
  94  */
  95 static _glapi_proc
  96 get_static_proc_address(const char *funcName)
  97 {
  98    const glprocs_table_t * const f = get_static_proc( funcName );
  99    if (f == NULL) {
 100       return NULL;
 101    }
 102
 103 #if defined(DISPATCH_FUNCTION_SIZE) && defined(GLX_INDIRECT_RENDERING)
 104    return (f->Address == NULL)
 105       ? get_entrypoint_address(f->Offset)
 106       : f->Address;
 107 #elif defined(DISPATCH_FUNCTION_SIZE)
 108    return get_entrypoint_address(f->Offset);
 109 #else
 110    return f->Address;
 111 #endif
 112 }
 113
 114
 115
 116 /**
 117  * Return the name of the function at the given offset in the dispatch
 118  * table.  For debugging only.
 119  */
 120 static const char *
 121 get_static_proc_name( GLuint offset )
 122 {
 123    GLuint i;
 124    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
 125       if (static_functions[i].Offset == offset) {
 126          return gl_string_table + static_functions[i].Name_offset;
 127       }
 128    }
 129    return NULL;
 130 }
 131
 132
 133
 134 /**********************************************************************
 135  * Extension function management.
 136  */
 137
 138
 139 /**
 140  * Track information about a function added to the GL API.
 141  */
 142 struct _glapi_function {
 143    /**
 144     * Name of the function.
 145     */
 146    const char * name;
 147
 148
 149    /**
 150     * Text string that describes the types of the parameters passed to the
 151     * named function.   Parameter types are converted to characters using the
 152     * following rules:
 153     *   - 'i' for \c GLint, \c GLuint, and \c GLenum
 154     *   - 'p' for any pointer type
 155     *   - 'f' for \c GLfloat and \c GLclampf
 156     *   - 'd' for \c GLdouble and \c GLclampd
 157     */
 158    const char * parameter_signature;
 159
 160
 161    /**
 162     * Offset in the dispatch table where the pointer to the real function is
 163     * located.  If the driver has not requested that the named function be
 164     * added to the dispatch table, this will have the value ~0.
 165     */
 166    unsigned dispatch_offset;
 167
 168
 169    /**
 170     * Pointer to the dispatch stub for the named function.
 171     *
 172     * \todo
 173     * The semantic of this field should be changed slightly.  Currently, it
 174     * is always expected to be non-\c NULL.  However, it would be better to
 175     * only allocate the entry-point stub when the application requests the
 176     * function via \c glXGetProcAddress.  This would save memory for all the
 177     * functions that the driver exports but that the application never wants
 178     * to call.
 179     */
 180    _glapi_proc dispatch_stub;
 181 };
 182
 183
 184 static struct _glapi_function ExtEntryTable[MAX_EXTENSION_FUNCS];
 185 static GLuint NumExtEntryPoints = 0;
 186
 187
 188 static struct _glapi_function *
 189 get_extension_proc(const char *funcName)
 190 {
 191    GLuint i;
 192    for (i = 0; i < NumExtEntryPoints; i++) {
 193       if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
 194          return & ExtEntryTable[i];
 195       }
 196    }
 197    return NULL;
 198 }
 199
 200
 201 static GLint
 202 get_extension_proc_offset(const char *funcName)
 203 {
 204    const struct _glapi_function * const f = get_extension_proc( funcName );
 205    if (f == NULL) {
 206       return -1;
 207    }
 208
 209    return f->dispatch_offset;
 210 }
 211
 212
 213 static _glapi_proc
 214 get_extension_proc_address(const char *funcName)
 215 {
 216    const struct _glapi_function * const f = get_extension_proc( funcName );
 217    if (f == NULL) {
 218       return NULL;
 219    }
 220
 221    return f->dispatch_stub;
 222 }
 223
 224
 225 static const char *
 226 get_extension_proc_name(GLuint offset)
 227 {
 228    GLuint i;
 229    for (i = 0; i < NumExtEntryPoints; i++) {
 230       if (ExtEntryTable[i].dispatch_offset == offset) {
 231          return ExtEntryTable[i].name;
 232       }
 233    }
 234    return NULL;
 235 }
 236
 237
 238 /**
 239  * strdup() is actually not a standard ANSI C or POSIX routine.
 240  * Irix will not define it if ANSI mode is in effect.
 241  */
 242 static char *
 243 str_dup(const char *str)
 244 {
 245    char *copy;
 246    copy = malloc(strlen(str) + 1);
 247    if (!copy)
 248       return NULL;
 249    strcpy(copy, str);
 250    return copy;
 251 }
 252
 253
 254 /**
 255  * Generate new entrypoint
 256  *
 257  * Use a temporary dispatch offset of ~0 (i.e. -1).  Later, when the driver
 258  * calls \c _glapi_add_dispatch we'll put in the proper offset.  If that
 259  * never happens, and the user calls this function, he'll segfault.  That's
 260  * what you get when you try calling a GL function that doesn't really exist.
 261  *
 262  * \param funcName  Name of the function to create an entry-point for.
 263  *
 264  * \sa _glapi_add_entrypoint
 265  */
 266
 267 static struct _glapi_function *
 268 add_function_name( const char * funcName )
 269 {
 270    struct _glapi_function * entry = NULL;
 271    _glapi_proc entrypoint = NULL;
 272    char * name_dup = NULL;
 273
 274    if (NumExtEntryPoints >= MAX_EXTENSION_FUNCS)
 275       return NULL;
 276
 277    if (funcName == NULL)
 278       return NULL;
 279
 280    name_dup = str_dup(funcName);
 281    if (name_dup == NULL)
 282       return NULL;
 283
 284    entrypoint = generate_entrypoint(~0);
 285
 286    if (entrypoint == NULL) {
 287       free(name_dup);
 288       return NULL;
 289    }
 290
 291    entry = & ExtEntryTable[NumExtEntryPoints];
 292    NumExtEntryPoints++;
 293
 294    entry->name = name_dup;
 295    entry->parameter_signature = NULL;
 296    entry->dispatch_offset = ~0;
 297    entry->dispatch_stub = entrypoint;
 298
 299    return entry;
 300 }
 301
 302
 303 static struct _glapi_function *
 304 set_entry_info( struct _glapi_function * entry, const char * signature, unsigned offset )
 305 {
 306    char * sig_dup = NULL;
 307
 308    if (signature == NULL)
 309       return NULL;
 310
 311    sig_dup = str_dup(signature);
 312    if (sig_dup == NULL)
 313       return NULL;
 314
 315    fill_in_entrypoint_offset(entry->dispatch_stub, offset);
 316
 317    entry->parameter_signature = sig_dup;
 318    entry->dispatch_offset = offset;
 319
 320    return entry;
 321 }
 322
 323
 324 /**
 325  * Fill-in the dispatch stub for the named function.
 326  *
 327  * This function is intended to be called by a hardware driver.  When called,
 328  * a dispatch stub may be created for the function.  A pointer to this
 329  * dispatch function will be returned by glXGetProcAddress.
 330  *
 331  * \param function_names       Array of pointers to function names that should
 332  *                             share a common dispatch offset.
 333  * \param parameter_signature  String representing the types of the parameters
 334  *                             passed to the named function.  Parameter types
 335  *                             are converted to characters using the following
 336  *                             rules:
 337  *                               - 'i' for \c GLint, \c GLuint, and \c GLenum
 338  *                               - 'p' for any pointer type
 339  *                               - 'f' for \c GLfloat and \c GLclampf
 340  *                               - 'd' for \c GLdouble and \c GLclampd
 341  *
 342  * \returns
 343  * The offset in the dispatch table of the named function.  A pointer to the
 344  * driver's implementation of the named function should be stored at
 345  * \c dispatch_table[\c offset].  Return -1 if error/problem.
 346  *
 347  * \sa glXGetProcAddress
 348  *
 349  * \warning
 350  * This function can only handle up to 8 names at a time.  As far as I know,
 351  * the maximum number of names ever associated with an existing GL function is
 352  * 4 (\c glPointParameterfSGIS, \c glPointParameterfEXT,
 353  * \c glPointParameterfARB, and \c glPointParameterf), so this should not be
 354  * too painful of a limitation.
 355  *
 356  * \todo
 357  * Determine whether or not \c parameter_signature should be allowed to be
 358  * \c NULL.  It doesn't seem like much of a hardship for drivers to have to
 359  * pass in an empty string.
 360  *
 361  * \todo
 362  * Determine if code should be added to reject function names that start with
 363  * 'glX'.
 364  *
 365  * \bug
 366  * Add code to compare \c parameter_signature with the parameter signature of
 367  * a static function.  In order to do that, we need to find a way to \b get
 368  * the parameter signature of a static function.
 369  */
 370
 371 int
 372 _glapi_add_dispatch( const char * const * function_names,
 373                      const char * parameter_signature )
 374 {
 375    static int next_dynamic_offset = FIRST_DYNAMIC_OFFSET;
 376    const char * const real_sig = (parameter_signature != NULL)
 377      ? parameter_signature : "";
 378    struct _glapi_function * entry[8];
 379    GLboolean is_static[8];
 380    unsigned i;
 381    int offset = ~0;
 382
 383    init_glapi_relocs_once();
 384
 385    (void) memset( is_static, 0, sizeof( is_static ) );
 386    (void) memset( entry, 0, sizeof( entry ) );
 387
 388    /* Find the _single_ dispatch offset for all function names that already
 389     * exist (and have a dispatch offset).
 390     */
 391
 392    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 393       const char * funcName = function_names[i];
 394       int static_offset;
 395       int extension_offset;
 396
 397       if (funcName[0] != 'g' || funcName[1] != 'l')
 398          return -1;
 399
 400       /* search built-in functions */
 401       static_offset = get_static_proc_offset(funcName);
 402
 403       if (static_offset >= 0) {
 404
 405          is_static[i] = GL_TRUE;
 406
 407          /* FIXME: Make sure the parameter signatures match!  How do we get
 408           * FIXME: the parameter signature for static functions?
 409           */
 410
 411          if ( (offset != ~0) && (static_offset != offset) ) {
 412             return -1;
 413          }
 414
 415          offset = static_offset;
 416
 417          continue;
 418       }
 419
 420       /* search added extension functions */
 421       entry[i] = get_extension_proc(funcName);
 422
 423       if (entry[i] != NULL) {
 424          extension_offset = entry[i]->dispatch_offset;
 425
 426          /* The offset may be ~0 if the function name was added by
 427           * glXGetProcAddress but never filled in by the driver.
 428           */
 429
 430          if (extension_offset == ~0) {
 431             continue;
 432          }
 433
 434          if (strcmp(real_sig, entry[i]->parameter_signature) != 0) {
 435             return -1;
 436          }
 437
 438          if ( (offset != ~0) && (extension_offset != offset) ) {
 439             return -1;
 440          }
 441
 442          offset = extension_offset;
 443       }
 444    }
 445
 446    /* If all function names are either new (or with no dispatch offset),
 447     * allocate a new dispatch offset.
 448     */
 449
 450    if (offset == ~0) {
 451       offset = next_dynamic_offset;
 452       next_dynamic_offset++;
 453    }
 454
 455    /* Fill in the dispatch offset for the new function names (and those with
 456     * no dispatch offset).
 457     */
 458
 459    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 460       if (is_static[i]) {
 461          continue;
 462       }
 463
 464       /* generate entrypoints for new function names */
 465       if (entry[i] == NULL) {
 466          entry[i] = add_function_name( function_names[i] );
 467          if (entry[i] == NULL) {
 468             /* FIXME: Possible memory leak here. */
 469             return -1;
 470          }
 471       }
 472
 473       if (entry[i]->dispatch_offset == ~0) {
 474          set_entry_info( entry[i], real_sig, offset );
 475       }
 476    }
 477
 478    return offset;
 479 }
 480
 481
 482 /**
 483  * Return offset of entrypoint for named function within dispatch table.
 484  */
 485 GLint
 486 _glapi_get_proc_offset(const char *funcName)
 487 {
 488    GLint offset;
 489
 490    /* search extension functions first */
 491    offset = get_extension_proc_offset(funcName);
 492    if (offset >= 0)
 493       return offset;
 494
 495    /* search static functions */
 496    return get_static_proc_offset(funcName);
 497 }
 498
 499
 500
 501 /**
 502  * Return pointer to the named function.  If the function name isn't found
 503  * in the name of static functions, try generating a new API entrypoint on
 504  * the fly with assembly language.
 505  */
 506 _glapi_proc
 507 _glapi_get_proc_address(const char *funcName)
 508 {
 509    _glapi_proc func;
 510    struct _glapi_function * entry;
 511
 512    init_glapi_relocs_once();
 513
 514 #ifdef USE_MGL_NAMESPACE
 515    if (funcName && funcName[0] == 'm')
 516       funcName++;
 517 #endif
 518
 519   if (!funcName || funcName[0] != 'g' || funcName[1] != 'l')
 520       return NULL;
 521
 522    /* search extension functions first */
 523    func = get_extension_proc_address(funcName);
 524    if (func)
 525       return func;
 526
 527    /* search static functions */
 528    func = get_static_proc_address(funcName);
 529    if (func)
 530       return func;
 531
 532    /* generate entrypoint, dispatch offset must be filled in by the driver */
 533    entry = add_function_name(funcName);
 534    if (entry == NULL)
 535       return NULL;
 536
 537    return entry->dispatch_stub;
 538 }
 539
 540
 541
 542 /**
 543  * Return the name of the function at the given dispatch offset.
 544  * This is only intended for debugging.
 545  */
 546 const char *
 547 _glapi_get_proc_name(GLuint offset)
 548 {
 549    const char * n;
 550
 551    /* search built-in functions */
 552    n = get_static_proc_name(offset);
 553    if ( n != NULL ) {
 554       return n;
 555    }
 556
 557    /* search added extension functions */
 558    return get_extension_proc_name(offset);
 559 }
 560
 561
 562
 563 /**********************************************************************
 564  * GL API table functions.
 565  */
 566
 567
 568 /**
 569  * Return size of dispatch table struct as number of functions (or
 570  * slots).
 571  */
 572 GLuint
 573 _glapi_get_dispatch_table_size(void)
 574 {
 575    /*
 576     * The dispatch table size (number of entries) is the size of the
 577     * _glapi_table struct plus the number of dynamic entries we can add.
 578     * The extra slots can be filled in by DRI drivers that register new
 579     * extension functions.
 580     */
 581    return FIRST_DYNAMIC_OFFSET + MAX_EXTENSION_FUNCS;
 582 }
 583
 584
 585 /**
 586  * Do some spot checks to be sure that the dispatch table
 587  * slots are assigned correctly. For debugging only.
 588  */
 589 void
 590 _glapi_check_table(const struct _glapi_table *table)
 591 {
 592 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
 593    {
 594       GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
 595       char *BeginFunc = (char*) &table->Begin;
 596       GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
 597       assert(BeginOffset == offset);
 598    }
 599    {
 600       GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
 601       char *viewportFunc = (char*) &table->Viewport;
 602       GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
 603       assert(viewportOffset == offset);
 604    }
 605    {
 606       GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
 607       char *VertexPointerFunc = (char*) &table->VertexPointer;
 608       GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
 609       assert(VertexPointerOffset == offset);
 610    }
 611    {
 612       GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
 613       char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
 614       GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
 615       assert(ResetMinMaxOffset == offset);
 616    }
 617    {
 618       GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
 619       char *blendColorFunc = (char*) &table->BlendColor;
 620       GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
 621       assert(blendColorOffset == offset);
 622    }
 623    {
 624       GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
 625       char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
 626       GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
 627       assert(secondaryColor3fOffset == offset);
 628    }
 629    {
 630       GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
 631       char *pointParameterivFunc = (char*) &table->PointParameterivNV;
 632       GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
 633       assert(pointParameterivOffset == offset);
 634    }
 635    {
 636       GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
 637       char *setFenceFunc = (char*) &table->SetFenceNV;
 638       GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
 639       assert(setFenceOffset == offset);
 640    }
 641 #else
 642    (void) table;
 643 #endif
 644 }