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    /* destroy the driver */
 190    if (mod->Driver && mod->Driver->Unload)
 191       mod->Driver->Unload(mod->Driver);
 192    if (mod->Handle)
 193       close_library(mod->Handle);
 194
 195    mod->Driver = NULL;
 196    mod->Handle = NULL;
 197 }
 198
 199
 200 /**
 201  * Add a module to the module array.
 202  */
 203 static _EGLModule *
 204 _eglAddModule(const char *path)
 205 {
 206    _EGLModule *mod;
 207    EGLint i;
 208
 209    if (!_eglModules) {
 210       _eglModules = _eglCreateArray("Module", 8);
 211       if (!_eglModules)
 212          return NULL;
 213    }
 214
 215    /* find duplicates */
 216    for (i = 0; i < _eglModules->Size; i++) {
 217       mod = _eglModules->Elements[i];
 218       if (strcmp(mod->Path, path) == 0)
 219          return mod;
 220    }
 221
 222    /* allocate a new one */
 223    mod = calloc(1, sizeof(*mod));
 224    if (mod) {
 225       mod->Path = _eglstrdup(path);
 226       if (!mod->Path) {
 227          free(mod);
 228          mod = NULL;
 229       }
 230    }
 231    if (mod) {
 232       _eglAppendArray(_eglModules, (void *) mod);
 233       _eglLog(_EGL_DEBUG, "added %s to module array", mod->Path);
 234    }
 235
 236    return mod;
 237 }
 238
 239
 240 /**
 241  * Free a module.
 242  */
 243 static void
 244 _eglFreeModule(void *module)
 245 {
 246    _EGLModule *mod = (_EGLModule *) module;
 247
 248    _eglUnloadModule(mod);
 249    free(mod->Path);
 250    free(mod);
 251 }
 252
 253
 254 /**
 255  * A loader function for use with _eglPreloadForEach.  The loader data is the
 256  * filename of the driver.   This function stops on the first valid driver.
 257  */
 258 static EGLBoolean
 259 _eglLoaderFile(const char *dir, size_t len, void *loader_data)
 260 {
 261    char path[1024];
 262    const char *filename = (const char *) loader_data;
 263    size_t flen = strlen(filename);
 264
 265    /* make a full path */
 266    if (len + flen + 2 > sizeof(path))
 267       return EGL_TRUE;
 268    if (len) {
 269       memcpy(path, dir, len);
 270       path[len++] = '/';
 271    }
 272    memcpy(path + len, filename, flen);
 273    len += flen;
 274    path[len] = '\0';
 275
 276    if (library_suffix()) {
 277       const char *suffix = library_suffix();
 278       size_t slen = strlen(suffix);
 279       const char *p;
 280       EGLBoolean need_suffix;
 281
 282       p = filename + flen - slen;
 283       need_suffix = (p < filename || strcmp(p, suffix) != 0);
 284       if (need_suffix) {
 285          /* overflow */
 286          if (len + slen + 1 > sizeof(path))
 287             return EGL_TRUE;
 288          strcpy(path + len, suffix);
 289       }
 290    }
 291
 292 #if defined(_EGL_OS_UNIX)
 293    /* check if the file exists */
 294    if (access(path, F_OK))
 295       return EGL_TRUE;
 296 #endif
 297
 298    _eglAddModule(path);
 299
 300    return EGL_TRUE;
 301 }
 302
 303
 304 /**
 305  * A loader function for use with _eglPreloadForEach.  The loader data is the
 306  * pattern (prefix) of the files to look for.
 307  */
 308 static EGLBoolean
 309 _eglLoaderPattern(const char *dir, size_t len, void *loader_data)
 310 {
 311 #if defined(_EGL_OS_UNIX)
 312    const char *prefix, *suffix;
 313    size_t prefix_len, suffix_len;
 314    DIR *dirp;
 315    struct dirent *dirent;
 316    char path[1024];
 317
 318    if (len + 2 > sizeof(path))
 319       return EGL_TRUE;
 320    if (len) {
 321       memcpy(path, dir, len);
 322       path[len++] = '/';
 323    }
 324    path[len] = '\0';
 325
 326    dirp = opendir(path);
 327    if (!dirp)
 328       return EGL_TRUE;
 329
 330    prefix = (const char *) loader_data;
 331    prefix_len = strlen(prefix);
 332    suffix = library_suffix();
 333    suffix_len = (suffix) ? strlen(suffix) : 0;
 334
 335    while ((dirent = readdir(dirp))) {
 336       size_t dirent_len = strlen(dirent->d_name);
 337       const char *p;
 338
 339       /* match the prefix */
 340       if (strncmp(dirent->d_name, prefix, prefix_len) != 0)
 341          continue;
 342       /* match the suffix */
 343       if (suffix) {
 344          p = dirent->d_name + dirent_len - suffix_len;
 345          if (p < dirent->d_name || strcmp(p, suffix) != 0)
 346             continue;
 347       }
 348
 349       /* make a full path and add it to the module array */
 350       if (len + dirent_len + 1 <= sizeof(path)) {
 351          strcpy(path + len, dirent->d_name);
 352          _eglAddModule(path);
 353       }
 354    }
 355
 356    closedir(dirp);
 357
 358    return EGL_TRUE;
 359 #else /* _EGL_OS_UNIX */
 360    /* stop immediately */
 361    return EGL_FALSE;
 362 #endif
 363 }
 364
 365
 366 /**
 367  * Run the callback function on each driver directory.
 368  *
 369  * The process may end prematurely if the callback function returns false.
 370  */
 371 static void
 372 _eglPreloadForEach(const char *search_path,
 373                    EGLBoolean (*loader)(const char *, size_t, void *),
 374                    void *loader_data)
 375 {
 376    const char *cur, *next;
 377    size_t len;
 378
 379    cur = search_path;
 380    while (cur) {
 381       next = strchr(cur, ':');
 382       len = (next) ? next - cur : strlen(cur);
 383
 384       if (!loader(cur, len, loader_data))
 385          break;
 386
 387       cur = (next) ? next + 1 : NULL;
 388    }
 389 }
 390
 391
 392 /**
 393  * Return a list of colon-separated driver directories.
 394  */
 395 static const char *
 396 _eglGetSearchPath(void)
 397 {
 398    static const char *search_path;
 399
 400 #if defined(_EGL_OS_UNIX) || defined(_EGL_OS_WINDOWS)
 401    if (!search_path) {
 402       static char buffer[1024];
 403       const char *p;
 404       int ret;
 405
 406       p = getenv("EGL_DRIVERS_PATH");
 407 #if defined(_EGL_OS_UNIX)
 408       if (p && (geteuid() != getuid() || getegid() != getgid())) {
 409          _eglLog(_EGL_DEBUG,
 410                "ignore EGL_DRIVERS_PATH for setuid/setgid binaries");
 411          p = NULL;
 412       }
 413 #endif /* _EGL_OS_UNIX */
 414
 415       if (p) {
 416          ret = _eglsnprintf(buffer, sizeof(buffer),
 417                "%s:%s", p, _EGL_DRIVER_SEARCH_DIR);
 418          if (ret > 0 && ret < sizeof(buffer))
 419             search_path = buffer;
 420       }
 421    }
 422    if (!search_path)
 423       search_path = _EGL_DRIVER_SEARCH_DIR;
 424 #else
 425    search_path = "";
 426 #endif
 427
 428    return search_path;
 429 }
 430
 431
 432 /**
 433  * Add the user driver to the module array.
 434  *
 435  * The user driver is specified by EGL_DRIVER.
 436  */
 437 static void
 438 _eglAddUserDriver(void)
 439 {
 440    const char *search_path = _eglGetSearchPath();
 441    char *env;
 442
 443    env = getenv("EGL_DRIVER");
 444 #if defined(_EGL_OS_UNIX)
 445    if (env && strchr(env, '/')) {
 446       search_path = "";
 447       if ((geteuid() != getuid() || getegid() != getgid())) {
 448          _eglLog(_EGL_DEBUG,
 449                "ignore EGL_DRIVER for setuid/setgid binaries");
 450          env = NULL;
 451       }
 452    }
 453 #endif /* _EGL_OS_UNIX */
 454    if (env)
 455       _eglPreloadForEach(search_path, _eglLoaderFile, (void *) env);
 456 }
 457
 458
 459 /**
 460  * Add default drivers to the module array.
 461  */
 462 static void
 463 _eglAddDefaultDrivers(void)
 464 {
 465    const char *search_path = _eglGetSearchPath();
 466    EGLint i;
 467 #if defined(_EGL_OS_WINDOWS)
 468    const char *DefaultDriverNames[] = {
 469       "egl_gallium"
 470    };
 471 #elif defined(_EGL_OS_UNIX)
 472    const char *DefaultDriverNames[] = {
 473       "egl_gallium",
 474       "egl_dri2",
 475       "egl_glx"
 476    };
 477 #endif
 478
 479    for (i = 0; i < ARRAY_SIZE(DefaultDriverNames); i++) {
 480       void *name = (void *) DefaultDriverNames[i];
 481       _eglPreloadForEach(search_path, _eglLoaderFile, name);
 482    }
 483 }
 484
 485
 486 /**
 487  * Add drivers to the module array.  Drivers will be loaded as they are matched
 488  * to displays.
 489  */
 490 static EGLBoolean
 491 _eglAddDrivers(void)
 492 {
 493    if (_eglModules)
 494       return EGL_TRUE;
 495
 496    /* the order here decides the priorities of the drivers */
 497    _eglAddUserDriver();
 498    _eglAddDefaultDrivers();
 499    _eglPreloadForEach(_eglGetSearchPath(), _eglLoaderPattern, (void *) "egl_");
 500
 501    return (_eglModules != NULL);
 502 }
 503
 504
 505 /**
 506  * Match a display to a driver.  The display is initialized unless use_probe is
 507  * true.
 508  *
 509  * The matching is done by finding the first driver that can initialize the
 510  * display, or when use_probe is true, the driver with highest score.
 511  */
 512 _EGLDriver *
 513 _eglMatchDriver(_EGLDisplay *dpy, EGLBoolean use_probe)
 514 {
 515    _EGLModule *mod;
 516    _EGLDriver *best_drv = NULL;
 517    EGLint best_score = 0;
 518    EGLint major, minor, i;
 519
 520    _eglLockMutex(&_eglModuleMutex);
 521
 522    if (!_eglAddDrivers()) {
 523       _eglUnlockMutex(&_eglModuleMutex);
 524       return EGL_FALSE;
 525    }
 526
 527    /* match the loaded modules */
 528    for (i = 0; i < _eglModules->Size; i++) {
 529       mod = (_EGLModule *) _eglModules->Elements[i];
 530       if (!mod->Driver)
 531          break;
 532
 533       if (use_probe) {
 534          EGLint score = (mod->Driver->Probe) ?
 535             mod->Driver->Probe(mod->Driver, dpy) : 1;
 536          if (score > best_score) {
 537             best_drv = mod->Driver;
 538             best_score = score;
 539          }
 540       }
 541       else {
 542          if (mod->Driver->API.Initialize(mod->Driver, dpy, &major, &minor)) {
 543             best_drv = mod->Driver;
 544             best_score = 100;
 545          }
 546       }
 547       /* perfect match */
 548       if (best_score >= 100)
 549          break;
 550    }
 551
 552    /* load more modules */
 553    if (!best_drv) {
 554       EGLint first_unloaded = i;
 555
 556       while (i < _eglModules->Size) {
 557          mod = (_EGLModule *) _eglModules->Elements[i];
 558          assert(!mod->Driver);
 559
 560          if (!_eglLoadModule(mod)) {
 561             /* remove invalid modules */
 562             _eglEraseArray(_eglModules, i, _eglFreeModule);
 563             continue;
 564          }
 565
 566          if (use_probe) {
 567             best_score = (mod->Driver->Probe) ?
 568                mod->Driver->Probe(mod->Driver, dpy) : 1;
 569          }
 570          else {
 571             if (mod->Driver->API.Initialize(mod->Driver, dpy, &major, &minor))
 572                best_score = 100;
 573          }
 574
 575          if (best_score > 0) {
 576             best_drv = mod->Driver;
 577             /* loaded modules come before unloaded ones */
 578             if (first_unloaded != i) {
 579                void *tmp = _eglModules->Elements[i];
 580                _eglModules->Elements[i] =
 581                   _eglModules->Elements[first_unloaded];
 582                _eglModules->Elements[first_unloaded] = tmp;
 583             }
 584             break;
 585          }
 586          else {
 587             _eglUnloadModule(mod);
 588             i++;
 589          }
 590       }
 591    }
 592
 593    _eglUnlockMutex(&_eglModuleMutex);
 594
 595    if (best_drv) {
 596       _eglLog(_EGL_DEBUG, "the best driver is %s (score %d)",
 597             best_drv->Name, best_score);
 598       if (!use_probe) {
 599          dpy->Driver = best_drv;
 600          dpy->Initialized = EGL_TRUE;
 601          dpy->APImajor = major;
 602          dpy->APIminor = minor;
 603       }
 604    }
 605
 606    return best_drv;
 607 }
 608
 609
 610 __eglMustCastToProperFunctionPointerType
 611 _eglGetDriverProc(const char *procname)
 612 {
 613    EGLint i;
 614    _EGLProc proc = NULL;
 615
 616    if (!_eglModules) {
 617       /* load the driver for the default display */
 618       EGLDisplay egldpy = eglGetDisplay(EGL_DEFAULT_DISPLAY);
 619       _EGLDisplay *dpy = _eglLookupDisplay(egldpy);
 620       if (!dpy || !_eglMatchDriver(dpy, EGL_TRUE))
 621          return NULL;
 622    }
 623
 624    for (i = 0; i < _eglModules->Size; i++) {
 625       _EGLModule *mod = (_EGLModule *) _eglModules->Elements[i];
 626
 627       if (!mod->Driver)
 628          break;
 629       proc = mod->Driver->API.GetProcAddress(mod->Driver, procname);
 630       if (proc)
 631          break;
 632    }
 633
 634    return proc;
 635 }
 636
 637
 638 /**
 639  * Unload all drivers.
 640  */
 641 void
 642 _eglUnloadDrivers(void)
 643 {
 644    /* this is called at atexit time */
 645    if (_eglModules) {
 646 #if defined(_EGL_OS_UNIX)
 647       _eglDestroyArray(_eglModules, _eglFreeModule);
 648 #elif defined(_EGL_OS_WINDOWS)
 649       /* XXX Windows unloads DLLs before atexit */
 650       _eglDestroyArray(_eglModules, NULL);
 651 #endif
 652       _eglModules = NULL;
 653    }
 654 }
 655
 656
 657 /**
 658  * Invoke a callback function on each EGL search path.
 659  *
 660  * The first argument of the callback function is the name of the search path.
 661  * The second argument is the length of the name.
 662  */
 663 void
 664 _eglSearchPathForEach(EGLBoolean (*callback)(const char *, size_t, void *),
 665                       void *callback_data)
 666 {
 667    const char *search_path = _eglGetSearchPath();
 668    _eglPreloadForEach(search_path, callback, callback_data);
 669 }