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 #ifdef MANGLE
  66       /* skip the prefix on the name */
  67       if (strcmp(testName, n + 1) == 0)
  68 #else
  69       if (strcmp(testName, n) == 0)
  70 #endif
  71       {
  72          return &static_functions[i];
  73       }
  74    }
  75    return NULL;
  76 }
  77
  78
  79 /**
  80  * Return dispatch table offset of the named static (built-in) function.
  81  * Return -1 if function not found.
  82  */
  83 static GLint
  84 get_static_proc_offset(const char *funcName)
  85 {
  86    const glprocs_table_t * const f = get_static_proc( funcName );
  87    if (f == NULL) {
  88       return -1;
  89    }
  90
  91    return f->Offset;
  92 }
  93
  94
  95
  96 /**
  97  * Return dispatch function address for the named static (built-in) function.
  98  * Return NULL if function not found.
  99  */
 100 static _glapi_proc
 101 get_static_proc_address(const char *funcName)
 102 {
 103    const glprocs_table_t * const f = get_static_proc( funcName );
 104    if (f == NULL) {
 105       return NULL;
 106    }
 107
 108 #if defined(DISPATCH_FUNCTION_SIZE) && defined(GLX_INDIRECT_RENDERING)
 109    return (f->Address == NULL)
 110       ? get_entrypoint_address(f->Offset)
 111       : f->Address;
 112 #elif defined(DISPATCH_FUNCTION_SIZE)
 113    return get_entrypoint_address(f->Offset);
 114 #else
 115    return f->Address;
 116 #endif
 117 }
 118
 119
 120
 121 /**
 122  * Return the name of the function at the given offset in the dispatch
 123  * table.  For debugging only.
 124  */
 125 static const char *
 126 get_static_proc_name( GLuint offset )
 127 {
 128    GLuint i;
 129    for (i = 0; static_functions[i].Name_offset >= 0; i++) {
 130       if (static_functions[i].Offset == offset) {
 131          return gl_string_table + static_functions[i].Name_offset;
 132       }
 133    }
 134    return NULL;
 135 }
 136
 137
 138
 139 /**********************************************************************
 140  * Extension function management.
 141  */
 142
 143
 144 /**
 145  * Track information about a function added to the GL API.
 146  */
 147 struct _glapi_function {
 148    /**
 149     * Name of the function.
 150     */
 151    const char * name;
 152
 153
 154    /**
 155     * Text string that describes the types of the parameters passed to the
 156     * named function.   Parameter types are converted to characters using the
 157     * following rules:
 158     *   - 'i' for \c GLint, \c GLuint, and \c GLenum
 159     *   - 'p' for any pointer type
 160     *   - 'f' for \c GLfloat and \c GLclampf
 161     *   - 'd' for \c GLdouble and \c GLclampd
 162     */
 163    const char * parameter_signature;
 164
 165
 166    /**
 167     * Offset in the dispatch table where the pointer to the real function is
 168     * located.  If the driver has not requested that the named function be
 169     * added to the dispatch table, this will have the value ~0.
 170     */
 171    unsigned dispatch_offset;
 172
 173
 174    /**
 175     * Pointer to the dispatch stub for the named function.
 176     *
 177     * \todo
 178     * The semantic of this field should be changed slightly.  Currently, it
 179     * is always expected to be non-\c NULL.  However, it would be better to
 180     * only allocate the entry-point stub when the application requests the
 181     * function via \c glXGetProcAddress.  This would save memory for all the
 182     * functions that the driver exports but that the application never wants
 183     * to call.
 184     */
 185    _glapi_proc dispatch_stub;
 186 };
 187
 188
 189 static struct _glapi_function ExtEntryTable[MAX_EXTENSION_FUNCS];
 190 static GLuint NumExtEntryPoints = 0;
 191
 192
 193 static struct _glapi_function *
 194 get_extension_proc(const char *funcName)
 195 {
 196    GLuint i;
 197    for (i = 0; i < NumExtEntryPoints; i++) {
 198       if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
 199          return & ExtEntryTable[i];
 200       }
 201    }
 202    return NULL;
 203 }
 204
 205
 206 static GLint
 207 get_extension_proc_offset(const char *funcName)
 208 {
 209    const struct _glapi_function * const f = get_extension_proc( funcName );
 210    if (f == NULL) {
 211       return -1;
 212    }
 213
 214    return f->dispatch_offset;
 215 }
 216
 217
 218 static _glapi_proc
 219 get_extension_proc_address(const char *funcName)
 220 {
 221    const struct _glapi_function * const f = get_extension_proc( funcName );
 222    if (f == NULL) {
 223       return NULL;
 224    }
 225
 226    return f->dispatch_stub;
 227 }
 228
 229
 230 static const char *
 231 get_extension_proc_name(GLuint offset)
 232 {
 233    GLuint i;
 234    for (i = 0; i < NumExtEntryPoints; i++) {
 235       if (ExtEntryTable[i].dispatch_offset == offset) {
 236          return ExtEntryTable[i].name;
 237       }
 238    }
 239    return NULL;
 240 }
 241
 242
 243 /**
 244  * strdup() is actually not a standard ANSI C or POSIX routine.
 245  * Irix will not define it if ANSI mode is in effect.
 246  */
 247 static char *
 248 str_dup(const char *str)
 249 {
 250    char *copy;
 251    copy = malloc(strlen(str) + 1);
 252    if (!copy)
 253       return NULL;
 254    strcpy(copy, str);
 255    return copy;
 256 }
 257
 258
 259 /**
 260  * Generate new entrypoint
 261  *
 262  * Use a temporary dispatch offset of ~0 (i.e. -1).  Later, when the driver
 263  * calls \c _glapi_add_dispatch we'll put in the proper offset.  If that
 264  * never happens, and the user calls this function, he'll segfault.  That's
 265  * what you get when you try calling a GL function that doesn't really exist.
 266  *
 267  * \param funcName  Name of the function to create an entry-point for.
 268  *
 269  * \sa _glapi_add_entrypoint
 270  */
 271
 272 static struct _glapi_function *
 273 add_function_name( const char * funcName )
 274 {
 275    struct _glapi_function * entry = NULL;
 276    _glapi_proc entrypoint = NULL;
 277    char * name_dup = NULL;
 278
 279    if (NumExtEntryPoints >= MAX_EXTENSION_FUNCS)
 280       return NULL;
 281
 282    if (funcName == NULL)
 283       return NULL;
 284
 285    name_dup = str_dup(funcName);
 286    if (name_dup == NULL)
 287       return NULL;
 288
 289    entrypoint = generate_entrypoint(~0);
 290
 291    if (entrypoint == NULL) {
 292       free(name_dup);
 293       return NULL;
 294    }
 295
 296    entry = & ExtEntryTable[NumExtEntryPoints];
 297    NumExtEntryPoints++;
 298
 299    entry->name = name_dup;
 300    entry->parameter_signature = NULL;
 301    entry->dispatch_offset = ~0;
 302    entry->dispatch_stub = entrypoint;
 303
 304    return entry;
 305 }
 306
 307
 308 static struct _glapi_function *
 309 set_entry_info( struct _glapi_function * entry, const char * signature, unsigned offset )
 310 {
 311    char * sig_dup = NULL;
 312
 313    if (signature == NULL)
 314       return NULL;
 315
 316    sig_dup = str_dup(signature);
 317    if (sig_dup == NULL)
 318       return NULL;
 319
 320    fill_in_entrypoint_offset(entry->dispatch_stub, offset);
 321
 322    entry->parameter_signature = sig_dup;
 323    entry->dispatch_offset = offset;
 324
 325    return entry;
 326 }
 327
 328
 329 /**
 330  * Fill-in the dispatch stub for the named function.
 331  *
 332  * This function is intended to be called by a hardware driver.  When called,
 333  * a dispatch stub may be created created for the function.  A pointer to this
 334  * dispatch function will be returned by glXGetProcAddress.
 335  *
 336  * \param function_names       Array of pointers to function names that should
 337  *                             share a common dispatch offset.
 338  * \param parameter_signature  String representing the types of the parameters
 339  *                             passed to the named function.  Parameter types
 340  *                             are converted to characters using the following
 341  *                             rules:
 342  *                               - 'i' for \c GLint, \c GLuint, and \c GLenum
 343  *                               - 'p' for any pointer type
 344  *                               - 'f' for \c GLfloat and \c GLclampf
 345  *                               - 'd' for \c GLdouble and \c GLclampd
 346  *
 347  * \returns
 348  * The offset in the dispatch table of the named function.  A pointer to the
 349  * driver's implementation of the named function should be stored at
 350  * \c dispatch_table[\c offset].  Return -1 if error/problem.
 351  *
 352  * \sa glXGetProcAddress
 353  *
 354  * \warning
 355  * This function can only handle up to 8 names at a time.  As far as I know,
 356  * the maximum number of names ever associated with an existing GL function is
 357  * 4 (\c glPointParameterfSGIS, \c glPointParameterfEXT,
 358  * \c glPointParameterfARB, and \c glPointParameterf), so this should not be
 359  * too painful of a limitation.
 360  *
 361  * \todo
 362  * Determine whether or not \c parameter_signature should be allowed to be
 363  * \c NULL.  It doesn't seem like much of a hardship for drivers to have to
 364  * pass in an empty string.
 365  *
 366  * \todo
 367  * Determine if code should be added to reject function names that start with
 368  * 'glX'.
 369  *
 370  * \bug
 371  * Add code to compare \c parameter_signature with the parameter signature of
 372  * a static function.  In order to do that, we need to find a way to \b get
 373  * the parameter signature of a static function.
 374  */
 375
 376 int
 377 _glapi_add_dispatch( const char * const * function_names,
 378                      const char * parameter_signature )
 379 {
 380    static int next_dynamic_offset = FIRST_DYNAMIC_OFFSET;
 381    const char * const real_sig = (parameter_signature != NULL)
 382      ? parameter_signature : "";
 383    struct _glapi_function * entry[8];
 384    GLboolean is_static[8];
 385    unsigned i;
 386    int offset = ~0;
 387
 388    init_glapi_relocs_once();
 389
 390    (void) memset( is_static, 0, sizeof( is_static ) );
 391    (void) memset( entry, 0, sizeof( entry ) );
 392
 393    /* Find the _single_ dispatch offset for all function names that already
 394     * exist (and have a dispatch offset).
 395     */
 396
 397    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 398       const char * funcName = function_names[i];
 399       int static_offset;
 400       int extension_offset;
 401
 402       if (funcName[0] != 'g' || funcName[1] != 'l')
 403          return -1;
 404
 405       /* search built-in functions */
 406       static_offset = get_static_proc_offset(funcName);
 407
 408       if (static_offset >= 0) {
 409
 410          is_static[i] = GL_TRUE;
 411
 412          /* FIXME: Make sure the parameter signatures match!  How do we get
 413           * FIXME: the parameter signature for static functions?
 414           */
 415
 416          if ( (offset != ~0) && (static_offset != offset) ) {
 417             return -1;
 418          }
 419
 420          offset = static_offset;
 421
 422          continue;
 423       }
 424
 425       /* search added extension functions */
 426       entry[i] = get_extension_proc(funcName);
 427
 428       if (entry[i] != NULL) {
 429          extension_offset = entry[i]->dispatch_offset;
 430
 431          /* The offset may be ~0 if the function name was added by
 432           * glXGetProcAddress but never filled in by the driver.
 433           */
 434
 435          if (extension_offset == ~0) {
 436             continue;
 437          }
 438
 439          if (strcmp(real_sig, entry[i]->parameter_signature) != 0) {
 440             return -1;
 441          }
 442
 443          if ( (offset != ~0) && (extension_offset != offset) ) {
 444             return -1;
 445          }
 446
 447          offset = extension_offset;
 448       }
 449    }
 450
 451    /* If all function names are either new (or with no dispatch offset),
 452     * allocate a new dispatch offset.
 453     */
 454
 455    if (offset == ~0) {
 456       offset = next_dynamic_offset;
 457       next_dynamic_offset++;
 458    }
 459
 460    /* Fill in the dispatch offset for the new function names (and those with
 461     * no dispatch offset).
 462     */
 463
 464    for ( i = 0 ; function_names[i] != NULL ; i++ ) {
 465       if (is_static[i]) {
 466          continue;
 467       }
 468
 469       /* generate entrypoints for new function names */
 470       if (entry[i] == NULL) {
 471          entry[i] = add_function_name( function_names[i] );
 472          if (entry[i] == NULL) {
 473             /* FIXME: Possible memory leak here. */
 474             return -1;
 475          }
 476       }
 477
 478       if (entry[i]->dispatch_offset == ~0) {
 479          set_entry_info( entry[i], real_sig, offset );
 480       }
 481    }
 482
 483    return offset;
 484 }
 485
 486
 487 /**
 488  * Return offset of entrypoint for named function within dispatch table.
 489  */
 490 GLint
 491 _glapi_get_proc_offset(const char *funcName)
 492 {
 493    GLint offset;
 494
 495    /* search extension functions first */
 496    offset = get_extension_proc_offset(funcName);
 497    if (offset >= 0)
 498       return offset;
 499
 500    /* search static functions */
 501    return get_static_proc_offset(funcName);
 502 }
 503
 504
 505
 506 /**
 507  * Return pointer to the named function.  If the function name isn't found
 508  * in the name of static functions, try generating a new API entrypoint on
 509  * the fly with assembly language.
 510  */
 511 _glapi_proc
 512 _glapi_get_proc_address(const char *funcName)
 513 {
 514    _glapi_proc func;
 515    struct _glapi_function * entry;
 516
 517    init_glapi_relocs_once();
 518
 519 #ifdef MANGLE
 520    /* skip the prefix on the name */
 521    if (funcName[1] != 'g' || funcName[2] != 'l')
 522       return NULL;
 523 #else
 524    if (funcName[0] != 'g' || funcName[1] != 'l')
 525       return NULL;
 526 #endif
 527
 528    /* search extension functions first */
 529    func = get_extension_proc_address(funcName);
 530    if (func)
 531       return func;
 532
 533    /* search static functions */
 534    func = get_static_proc_address(funcName);
 535    if (func)
 536       return func;
 537
 538    /* generate entrypoint, dispatch offset must be filled in by the driver */
 539    entry = add_function_name(funcName);
 540    if (entry == NULL)
 541       return NULL;
 542
 543    return entry->dispatch_stub;
 544 }
 545
 546
 547
 548 /**
 549  * Return the name of the function at the given dispatch offset.
 550  * This is only intended for debugging.
 551  */
 552 const char *
 553 _glapi_get_proc_name(GLuint offset)
 554 {
 555    const char * n;
 556
 557    /* search built-in functions */
 558    n = get_static_proc_name(offset);
 559    if ( n != NULL ) {
 560       return n;
 561    }
 562
 563    /* search added extension functions */
 564    return get_extension_proc_name(offset);
 565 }
 566
 567
 568
 569 /**********************************************************************
 570  * GL API table functions.
 571  */
 572
 573
 574 /**
 575  * Return size of dispatch table struct as number of functions (or
 576  * slots).
 577  */
 578 GLuint
 579 _glapi_get_dispatch_table_size(void)
 580 {
 581    /*
 582     * The dispatch table size (number of entries) is the size of the
 583     * _glapi_table struct plus the number of dynamic entries we can add.
 584     * The extra slots can be filled in by DRI drivers that register new
 585     * extension functions.
 586     */
 587    return FIRST_DYNAMIC_OFFSET + MAX_EXTENSION_FUNCS;
 588 }
 589
 590
 591 /**
 592  * Make sure there are no NULL pointers in the given dispatch table.
 593  * Intended for debugging purposes.
 594  */
 595 void
 596 _glapi_check_table_not_null(const struct _glapi_table *table)
 597 {
 598 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
 599    const GLuint entries = _glapi_get_dispatch_table_size();
 600    const void **tab = (const void **) table;
 601    GLuint i;
 602    for (i = 1; i < entries; i++) {
 603       assert(tab[i]);
 604    }
 605 #else
 606    (void) table;
 607 #endif
 608 }
 609
 610
 611 /**
 612  * Do some spot checks to be sure that the dispatch table
 613  * slots are assigned correctly. For debugging only.
 614  */
 615 void
 616 _glapi_check_table(const struct _glapi_table *table)
 617 {
 618 #ifdef EXTRA_DEBUG /* set to DEBUG for extra DEBUG */
 619    {
 620       GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
 621       char *BeginFunc = (char*) &table->Begin;
 622       GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
 623       assert(BeginOffset == offset);
 624    }
 625    {
 626       GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
 627       char *viewportFunc = (char*) &table->Viewport;
 628       GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
 629       assert(viewportOffset == offset);
 630    }
 631    {
 632       GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
 633       char *VertexPointerFunc = (char*) &table->VertexPointer;
 634       GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
 635       assert(VertexPointerOffset == offset);
 636    }
 637    {
 638       GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
 639       char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
 640       GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
 641       assert(ResetMinMaxOffset == offset);
 642    }
 643    {
 644       GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
 645       char *blendColorFunc = (char*) &table->BlendColor;
 646       GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
 647       assert(blendColorOffset == offset);
 648    }
 649    {
 650       GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
 651       char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
 652       GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
 653       assert(secondaryColor3fOffset == offset);
 654    }
 655    {
 656       GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
 657       char *pointParameterivFunc = (char*) &table->PointParameterivNV;
 658       GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
 659       assert(pointParameterivOffset == offset);
 660    }
 661    {
 662       GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
 663       char *setFenceFunc = (char*) &table->SetFenceNV;
 664       GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
 665       assert(setFenceOffset == offset);
 666    }
 667 #else
 668    (void) table;
 669 #endif
 670 }