src/egl/main/egldriver.c

   1 /**
   2  * Functions for choosing and opening/loading device drivers.
   3  */
   4
   5
   6 #include <assert.h>
   7 #include <string.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10
  11 #include "eglstring.h"
  12 #include "egldefines.h"
  13 #include "egldisplay.h"
  14 #include "egldriver.h"
  15 #include "egllog.h"
  16 #include "eglmutex.h"
  17
  18 #if defined(_EGL_OS_UNIX)
  19 #include <dlfcn.h>
  20 #include <sys/types.h>
  21 #include <dirent.h>
  22 #include <unistd.h>
  23 #endif
  24
  25
  26 typedef struct _egl_module {
  27    char *Path;
  28    void *Handle;
  29    _EGLDriver *Driver;
  30 } _EGLModule;
  31
  32 static _EGL_DECLARE_MUTEX(_eglModuleMutex);
  33 static _EGLArray *_eglModules;
  34
  35
  36 /**
  37  * Wrappers for dlopen/dlclose()
  38  */
  39 #if defined(_EGL_OS_WINDOWS)
  40
  41
  42 typedef HMODULE lib_handle;
  43
  44 static HMODULE
  45 open_library(const char *filename)
  46 {
  47    return LoadLibrary(filename);
  48 }
  49
  50 static void
  51 close_library(HMODULE lib)
  52 {
  53    FreeLibrary(lib);
  54 }
  55
  56
  57 static const char *
  58 library_suffix(void)
  59 {
  60    return ".dll";
  61 }
  62
  63
  64 #elif defined(_EGL_OS_UNIX)
  65
  66
  67 typedef void * lib_handle;
  68
  69 static void *
  70 open_library(const char *filename)
  71 {
  72    return dlopen(filename, RTLD_LAZY);
  73 }
  74
  75 static void
  76 close_library(void *lib)
  77 {
  78    dlclose(lib);
  79 }
  80
  81
  82 static const char *
  83 library_suffix(void)
  84 {
  85    return ".so";
  86 }
  87
  88
  89 #endif
  90
  91
  92 /**
  93  * Open the named driver and find its bootstrap function: _eglMain().
  94  */
  95 static _EGLMain_t
  96 _eglOpenLibrary(const char *driverPath, lib_handle *handle)
  97 {
  98    lib_handle lib;
  99    _EGLMain_t mainFunc = NULL;
 100    const char *error = "unknown error";
 101
 102    assert(driverPath);
 103
 104    _eglLog(_EGL_DEBUG, "dlopen(%s)", driverPath);
 105    lib = open_library(driverPath);
 106
 107 #if defined(_EGL_OS_WINDOWS)
 108    /* XXX untested */
 109    if (lib)
 110       mainFunc = (_EGLMain_t) GetProcAddress(lib, "_eglMain");
 111 #elif defined(_EGL_OS_UNIX)
 112    if (lib) {
 113       union {
 114          _EGLMain_t func;
 115          void *ptr;
 116       } tmp = { NULL };
 117       /* direct cast gives a warning when compiled with -pedantic */
 118       tmp.ptr = dlsym(lib, "_eglMain");
 119       mainFunc = tmp.func;
 120       if (!mainFunc)
 121          error = dlerror();
 122    }
 123    else {
 124       error = dlerror();
 125    }
 126 #endif
 127
 128    if (!lib) {
 129       _eglLog(_EGL_WARNING, "Could not open driver %s (%s)",
 130               driverPath, error);
 131       if (!getenv("EGL_DRIVER"))
 132          _eglLog(_EGL_WARNING,
 133                  "The driver can be overridden by setting EGL_DRIVER");
 134       return NULL;
 135    }
 136
 137    if (!mainFunc) {
 138       _eglLog(_EGL_WARNING, "_eglMain not found in %s (%s)",
 139               driverPath, error);
 140       if (lib)
 141          close_library(lib);
 142       return NULL;
 143    }
 144
 145    *handle = lib;
 146    return mainFunc;
 147 }
 148
 149
 150 /**
 151  * Load a module and create the driver object.
 152  */
 153 static EGLBoolean
 154 _eglLoadModule(_EGLModule *mod)
 155 {
 156    _EGLMain_t mainFunc;
 157    lib_handle lib;
 158    _EGLDriver *drv;
 159
 160    mainFunc = _eglOpenLibrary(mod->Path, &lib);
 161    if (!mainFunc)
 162       return EGL_FALSE;
 163
 164    drv = mainFunc(NULL);
 165    if (!drv) {
 166       if (lib)
 167          close_library(lib);
 168       return EGL_FALSE;
 169    }
 170
 171    if (!drv->Name) {
 172       _eglLog(_EGL_WARNING, "Driver loaded from %s has no name", mod->Path);
 173       drv->Name = "UNNAMED";
 174    }
 175
 176    mod->Handle = (void *) lib;
 177    mod->Driver = drv;
 178
 179    return EGL_TRUE;
 180 }
 181
 182
 183 /**
 184  * Unload a module.
 185  */
 186 static void
 187 _eglUnloadModule(_EGLModule *mod)
 188 {
 189 #if defined(_EGL_OS_UNIX)
 190    /* destroy the driver */
 191    if (mod->Driver && mod->Driver->Unload)
 192       mod->Driver->Unload(mod->Driver);
 193
 194    /*
 195     * XXX At this point (atexit), the module might be the last reference to
 196     * libEGL.  Closing the module might unmap libEGL and give problems.
 197     */
 198 #if 0
 199    if (mod->Handle)
 200       close_library(mod->Handle);
 201 #endif
 202 #elif defined(_EGL_OS_WINDOWS)
 203    /* XXX Windows unloads DLLs before atexit */
 204 #endif
 205
 206    mod->Driver = NULL;
 207    mod->Handle = NULL;
 208 }
 209
 210
 211 /**
 212  * Add a module to the module array.
 213  */
 214 static _EGLModule *
 215 _eglAddModule(const char *path)
 216 {
 217    _EGLModule *mod;
 218    EGLint i;
 219
 220    if (!_eglModules) {
 221       _eglModules = _eglCreateArray("Module", 8);
 222       if (!_eglModules)
 223          return NULL;
 224    }
 225
 226    /* find duplicates */
 227    for (i = 0; i < _eglModules->Size; i++) {
 228       mod = _eglModules->Elements[i];
 229       if (strcmp(mod->Path, path) == 0)
 230          return mod;
 231    }
 232
 233    /* allocate a new one */
 234    mod = calloc(1, sizeof(*mod));
 235    if (mod) {
 236       mod->Path = _eglstrdup(path);
 237       if (!mod->Path) {
 238          free(mod);
 239          mod = NULL;
 240       }
 241    }
 242    if (mod) {
 243       _eglAppendArray(_eglModules, (void *) mod);
 244       _eglLog(_EGL_DEBUG, "added %s to module array", mod->Path);
 245    }
 246
 247    return mod;
 248 }
 249
 250
 251 /**
 252  * Free a module.
 253  */
 254 static void
 255 _eglFreeModule(void *module)
 256 {
 257    _EGLModule *mod = (_EGLModule *) module;
 258
 259    _eglUnloadModule(mod);
 260    free(mod->Path);
 261    free(mod);
 262 }
 263
 264
 265 /**
 266  * A loader function for use with _eglPreloadForEach.  The loader data is the
 267  * filename of the driver.   This function stops on the first valid driver.
 268  */
 269 static EGLBoolean
 270 _eglLoaderFile(const char *dir, size_t len, void *loader_data)
 271 {
 272    char path[1024];
 273    const char *filename = (const char *) loader_data;
 274    size_t flen = strlen(filename);
 275
 276    /* make a full path */
 277    if (len + flen + 2 > sizeof(path))
 278       return EGL_TRUE;
 279    if (len) {
 280       memcpy(path, dir, len);
 281       path[len++] = '/';
 282    }
 283    memcpy(path + len, filename, flen);
 284    len += flen;
 285    path[len] = '\0';
 286
 287    if (library_suffix()) {
 288       const char *suffix = library_suffix();
 289       size_t slen = strlen(suffix);
 290       const char *p;
 291       EGLBoolean need_suffix;
 292
 293       p = filename + flen - slen;
 294       need_suffix = (p < filename || strcmp(p, suffix) != 0);
 295       if (need_suffix) {
 296          /* overflow */
 297          if (len + slen + 1 > sizeof(path))
 298             return EGL_TRUE;
 299          strcpy(path + len, suffix);
 300       }
 301    }
 302
 303 #if defined(_EGL_OS_UNIX)
 304    /* check if the file exists */
 305    if (access(path, F_OK))
 306       return EGL_TRUE;
 307 #endif
 308
 309    _eglAddModule(path);
 310
 311    return EGL_TRUE;
 312 }
 313
 314
 315 /**
 316  * A loader function for use with _eglPreloadForEach.  The loader data is the
 317  * pattern (prefix) of the files to look for.
 318  */
 319 static EGLBoolean
 320 _eglLoaderPattern(const char *dir, size_t len, void *loader_data)
 321 {
 322 #if defined(_EGL_OS_UNIX)
 323    const char *prefix, *suffix;
 324    size_t prefix_len, suffix_len;
 325    DIR *dirp;
 326    struct dirent *dirent;
 327    char path[1024];
 328
 329    if (len + 2 > sizeof(path))
 330       return EGL_TRUE;
 331    if (len) {
 332       memcpy(path, dir, len);
 333       path[len++] = '/';
 334    }
 335    path[len] = '\0';
 336
 337    dirp = opendir(path);
 338    if (!dirp)
 339       return EGL_TRUE;
 340
 341    prefix = (const char *) loader_data;
 342    prefix_len = strlen(prefix);
 343    suffix = library_suffix();
 344    suffix_len = (suffix) ? strlen(suffix) : 0;
 345
 346    while ((dirent = readdir(dirp))) {
 347       size_t dirent_len = strlen(dirent->d_name);
 348       const char *p;
 349
 350       /* match the prefix */
 351       if (strncmp(dirent->d_name, prefix, prefix_len) != 0)
 352          continue;
 353       /* match the suffix */
 354       if (suffix) {
 355          p = dirent->d_name + dirent_len - suffix_len;
 356          if (p < dirent->d_name || strcmp(p, suffix) != 0)
 357             continue;
 358       }
 359
 360       /* make a full path and add it to the module array */
 361       if (len + dirent_len + 1 <= sizeof(path)) {
 362          strcpy(path + len, dirent->d_name);
 363          _eglAddModule(path);
 364       }
 365    }
 366
 367    closedir(dirp);
 368
 369    return EGL_TRUE;
 370 #else /* _EGL_OS_UNIX */
 371    /* stop immediately */
 372    return EGL_FALSE;
 373 #endif
 374 }
 375
 376
 377 /**
 378  * Run the callback function on each driver directory.
 379  *
 380  * The process may end prematurely if the callback function returns false.
 381  */
 382 static void
 383 _eglPreloadForEach(const char *search_path,
 384                    EGLBoolean (*loader)(const char *, size_t, void *),
 385                    void *loader_data)
 386 {
 387    const char *cur, *next;
 388    size_t len;
 389
 390    cur = search_path;
 391    while (cur) {
 392       next = strchr(cur, ':');
 393       len = (next) ? next - cur : strlen(cur);
 394
 395       if (!loader(cur, len, loader_data))
 396          break;
 397
 398       cur = (next) ? next + 1 : NULL;
 399    }
 400 }
 401
 402
 403 /**
 404  * Return a list of colon-separated driver directories.
 405  */
 406 static const char *
 407 _eglGetSearchPath(void)
 408 {
 409    static char search_path[1024];
 410
 411 #if defined(_EGL_OS_UNIX) || defined(_EGL_OS_WINDOWS)
 412    if (search_path[0] == '\0') {
 413       char *buf = search_path;
 414       size_t len = sizeof(search_path);
 415       EGLBoolean use_env;
 416       char dir_sep;
 417       int ret;
 418
 419 #if defined(_EGL_OS_UNIX)
 420       use_env = (geteuid() == getuid() && getegid() == getgid());
 421       dir_sep = '/';
 422 #else
 423       use_env = EGL_TRUE;
 424       dir_sep = '\\';
 425 #endif
 426
 427       if (use_env) {
 428          char *p;
 429
 430          /* extract the dirname from EGL_DRIVER */
 431          p = getenv("EGL_DRIVER");
 432          if (p && strchr(p, dir_sep)) {
 433             ret = _eglsnprintf(buf, len, "%s", p);
 434             if (ret > 0 && ret < len) {
 435                p = strrchr(buf, dir_sep);
 436                *p++ = ':';
 437
 438                len -= p - buf;
 439                buf = p;
 440             }
 441          }
 442
 443          /* append EGL_DRIVERS_PATH */
 444          p = getenv("EGL_DRIVERS_PATH");
 445          if (p) {
 446             ret = _eglsnprintf(buf, len, "%s:", p);
 447             if (ret > 0 && ret < len) {
 448                buf += ret;
 449                len -= ret;
 450             }
 451          }
 452       }
 453       else {
 454          _eglLog(_EGL_DEBUG,
 455                "ignore EGL_DRIVERS_PATH for setuid/setgid binaries");
 456       }
 457
 458       ret = _eglsnprintf(buf, len, "%s", _EGL_DRIVER_SEARCH_DIR);
 459       if (ret < 0 || ret >= len)
 460          search_path[0] = '\0';
 461
 462       _eglLog(_EGL_DEBUG, "EGL search path is %s", search_path);
 463    }
 464 #endif /* defined(_EGL_OS_UNIX) || defined(_EGL_OS_WINDOWS) */
 465
 466    return search_path;
 467 }
 468
 469
 470 /**
 471  * Add the user driver to the module array.
 472  *
 473  * The user driver is specified by EGL_DRIVER.
 474  */
 475 static void
 476 _eglAddUserDriver(void)
 477 {
 478    const char *search_path = _eglGetSearchPath();
 479    char *env;
 480
 481    env = getenv("EGL_DRIVER");
 482 #if defined(_EGL_OS_UNIX)
 483    if (env && strchr(env, '/')) {
 484       search_path = "";
 485       if ((geteuid() != getuid() || getegid() != getgid())) {
 486          _eglLog(_EGL_DEBUG,
 487                "ignore EGL_DRIVER for setuid/setgid binaries");
 488          env = NULL;
 489       }
 490    }
 491 #endif /* _EGL_OS_UNIX */
 492    if (env)
 493       _eglPreloadForEach(search_path, _eglLoaderFile, (void *) env);
 494 }
 495
 496
 497 /**
 498  * Add default drivers to the module array.
 499  */
 500 static void
 501 _eglAddDefaultDrivers(void)
 502 {
 503    const char *search_path = _eglGetSearchPath();
 504    EGLint i;
 505 #if defined(_EGL_OS_WINDOWS)
 506    const char *DefaultDriverNames[] = {
 507       "egl_gallium"
 508    };
 509 #elif defined(_EGL_OS_UNIX)
 510    const char *DefaultDriverNames[] = {
 511       "egl_gallium",
 512       "egl_dri2",
 513       "egl_glx"
 514    };
 515 #endif
 516
 517    for (i = 0; i < ARRAY_SIZE(DefaultDriverNames); i++) {
 518       void *name = (void *) DefaultDriverNames[i];
 519       _eglPreloadForEach(search_path, _eglLoaderFile, name);
 520    }
 521 }
 522
 523
 524 /**
 525  * Add drivers to the module array.  Drivers will be loaded as they are matched
 526  * to displays.
 527  */
 528 static EGLBoolean
 529 _eglAddDrivers(void)
 530 {
 531    if (_eglModules)
 532       return EGL_TRUE;
 533
 534    /* the order here decides the priorities of the drivers */
 535    _eglAddUserDriver();
 536    _eglAddDefaultDrivers();
 537    _eglPreloadForEach(_eglGetSearchPath(), _eglLoaderPattern, (void *) "egl_");
 538
 539    return (_eglModules != NULL);
 540 }
 541
 542
 543 /**
 544  * Match a display to a driver.  The display is initialized unless use_probe is
 545  * true.
 546  *
 547  * The matching is done by finding the first driver that can initialize the
 548  * display, or when use_probe is true, the driver with highest score.
 549  */
 550 _EGLDriver *
 551 _eglMatchDriver(_EGLDisplay *dpy, EGLBoolean use_probe)
 552 {
 553    _EGLModule *mod;
 554    _EGLDriver *best_drv = NULL;
 555    EGLint best_score = 0;
 556    EGLint major, minor, i;
 557
 558    _eglLockMutex(&_eglModuleMutex);
 559
 560    if (!_eglAddDrivers()) {
 561       _eglUnlockMutex(&_eglModuleMutex);
 562       return EGL_FALSE;
 563    }
 564
 565    /* match the loaded modules */
 566    for (i = 0; i < _eglModules->Size; i++) {
 567       mod = (_EGLModule *) _eglModules->Elements[i];
 568       if (!mod->Driver)
 569          break;
 570
 571       if (use_probe) {
 572          EGLint score = (mod->Driver->Probe) ?
 573             mod->Driver->Probe(mod->Driver, dpy) : 1;
 574          if (score > best_score) {
 575             best_drv = mod->Driver;
 576             best_score = score;
 577          }
 578       }
 579       else {
 580          if (mod->Driver->API.Initialize(mod->Driver, dpy, &major, &minor)) {
 581             best_drv = mod->Driver;
 582             best_score = 100;
 583          }
 584       }
 585       /* perfect match */
 586       if (best_score >= 100)
 587          break;
 588    }
 589
 590    /* load more modules */
 591    if (!best_drv) {
 592       EGLint first_unloaded = i;
 593
 594       while (i < _eglModules->Size) {
 595          mod = (_EGLModule *) _eglModules->Elements[i];
 596          assert(!mod->Driver);
 597
 598          if (!_eglLoadModule(mod)) {
 599             /* remove invalid modules */
 600             _eglEraseArray(_eglModules, i, _eglFreeModule);
 601             continue;
 602          }
 603
 604          if (use_probe) {
 605             best_score = (mod->Driver->Probe) ?
 606                mod->Driver->Probe(mod->Driver, dpy) : 1;
 607          }
 608          else {
 609             if (mod->Driver->API.Initialize(mod->Driver, dpy, &major, &minor))
 610                best_score = 100;
 611          }
 612
 613          if (best_score > 0) {
 614             best_drv = mod->Driver;
 615             /* loaded modules come before unloaded ones */
 616             if (first_unloaded != i) {
 617                void *tmp = _eglModules->Elements[i];
 618                _eglModules->Elements[i] =
 619                   _eglModules->Elements[first_unloaded];
 620                _eglModules->Elements[first_unloaded] = tmp;
 621             }
 622             break;
 623          }
 624          else {
 625             _eglUnloadModule(mod);
 626             i++;
 627          }
 628       }
 629    }
 630
 631    _eglUnlockMutex(&_eglModuleMutex);
 632
 633    if (best_drv) {
 634       _eglLog(_EGL_DEBUG, "the best driver is %s (score %d)",
 635             best_drv->Name, best_score);
 636       if (!use_probe) {
 637          dpy->Driver = best_drv;
 638          dpy->Initialized = EGL_TRUE;
 639          dpy->APImajor = major;
 640          dpy->APIminor = minor;
 641       }
 642    }
 643
 644    return best_drv;
 645 }
 646
 647
 648 __eglMustCastToProperFunctionPointerType
 649 _eglGetDriverProc(const char *procname)
 650 {
 651    EGLint i;
 652    _EGLProc proc = NULL;
 653
 654    if (!_eglModules) {
 655       /* load the driver for the default display */
 656       EGLDisplay egldpy = eglGetDisplay(EGL_DEFAULT_DISPLAY);
 657       _EGLDisplay *dpy = _eglLookupDisplay(egldpy);
 658       if (!dpy || !_eglMatchDriver(dpy, EGL_TRUE))
 659          return NULL;
 660    }
 661
 662    for (i = 0; i < _eglModules->Size; i++) {
 663       _EGLModule *mod = (_EGLModule *) _eglModules->Elements[i];
 664
 665       if (!mod->Driver)
 666          break;
 667       proc = mod->Driver->API.GetProcAddress(mod->Driver, procname);
 668       if (proc)
 669          break;
 670    }
 671
 672    return proc;
 673 }
 674
 675
 676 /**
 677  * Unload all drivers.
 678  */
 679 void
 680 _eglUnloadDrivers(void)
 681 {
 682    /* this is called at atexit time */
 683    if (_eglModules) {
 684       _eglDestroyArray(_eglModules, _eglFreeModule);
 685       _eglModules = NULL;
 686    }
 687 }
 688
 689
 690 /**
 691  * Invoke a callback function on each EGL search path.
 692  *
 693  * The first argument of the callback function is the name of the search path.
 694  * The second argument is the length of the name.
 695  */
 696 void
 697 _eglSearchPathForEach(EGLBoolean (*callback)(const char *, size_t, void *),
 698                       void *callback_data)
 699 {
 700    const char *search_path = _eglGetSearchPath();
 701    _eglPreloadForEach(search_path, callback, callback_data);
 702 }