dyld3/PathOverrides.cpp

   1 /*
   2  * Copyright (c) 2017 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24
  25
  26 #include <stdint.h>
  27 #include <string.h>
  28 #include <assert.h>
  29 #include <uuid/uuid.h>
  30 #include <mach/mach.h>
  31 #include <sys/stat.h>
  32 #include <fcntl.h>
  33 #include <limits.h>
  34 #include <sys/errno.h>
  35 #include <unistd.h>
  36
  37 #include <initializer_list>
  38
  39 #include "PathOverrides.h"
  40
  41
  42
  43 namespace dyld3 {
  44 namespace closure {
  45
  46 #if BUILDING_LIBDYLD
  47 PathOverrides   gPathOverrides;
  48 #endif
  49
  50
  51 // based on ANSI-C strstr()
  52 static const char* strrstr(const char* str, const char* sub)
  53 {
  54     const size_t sublen = strlen(sub);
  55     for(const char* p = &str[strlen(str)]; p != str; --p) {
  56         if ( strncmp(p, sub, sublen) == 0 )
  57             return p;
  58     }
  59     return NULL;
  60 }
  61
  62
  63 void PathOverrides::setFallbackPathHandling(FallbackPathMode mode)
  64 {
  65     _fallbackPathMode = mode;
  66 }
  67
  68 void PathOverrides::setEnvVars(const char* envp[], const MachOFile* mainExe, const char* mainExePath)
  69 {
  70     for (const char** p = envp; *p != NULL; p++) {
  71         addEnvVar(*p, false);
  72     }
  73     if ( mainExe != nullptr )
  74         setMainExecutable(mainExe, mainExePath);
  75 }
  76
  77 void PathOverrides::setMainExecutable(const dyld3::MachOFile* mainExe, const char* mainExePath)
  78 {
  79     assert(mainExe != nullptr);
  80     assert(mainExe->isMainExecutable());
  81     // process any LC_DYLD_ENVIRONMENT load commands in main executable
  82         mainExe->forDyldEnv(^(const char* envVar, bool& stop) {
  83         addEnvVar(envVar, true);
  84         });
  85 }
  86
  87
  88 #if !BUILDING_LIBDYLD
  89 // libdyld is never unloaded
  90 PathOverrides::~PathOverrides()
  91 {
  92 }
  93 #endif
  94
  95 void PathOverrides::forEachInsertedDylib(void (^handler)(const char* dylibPath, bool &stop)) const
  96 {
  97     if ( _insertedDylibs != nullptr ) {
  98         forEachInColonList(_insertedDylibs, nullptr, ^(const char* path, bool &stop) {
  99             handler(path, stop);
 100         });
 101     }
 102 }
 103
 104 void PathOverrides::handleEnvVar(const char* key, const char* value, void (^handler)(const char* envVar)) const
 105 {
 106     if ( value == nullptr )
 107         return;
 108     size_t allocSize = strlen(key) + strlen(value) + 2;
 109     char buffer[allocSize];
 110     strlcpy(buffer, key, allocSize);
 111     strlcat(buffer, "=", allocSize);
 112     strlcat(buffer, value, allocSize);
 113     handler(buffer);
 114 }
 115
 116 // Note, this method only returns variables set on the environment, not those from the load command
 117 void PathOverrides::forEachEnvVar(void (^handler)(const char* envVar)) const
 118 {
 119     handleEnvVar("DYLD_LIBRARY_PATH",            _dylibPathOverridesEnv,        handler);
 120     handleEnvVar("DYLD_FRAMEWORK_PATH",          _frameworkPathOverridesEnv,    handler);
 121     handleEnvVar("DYLD_FALLBACK_FRAMEWORK_PATH", _frameworkPathFallbacksEnv,    handler);
 122     handleEnvVar("DYLD_FALLBACK_LIBRARY_PATH",   _dylibPathFallbacksEnv,        handler);
 123     handleEnvVar("DYLD_INSERT_LIBRARIES",        _insertedDylibs,               handler);
 124     handleEnvVar("DYLD_IMAGE_SUFFIX",            _imageSuffix,                  handler);
 125     handleEnvVar("DYLD_ROOT_PATH",               _rootPath,                     handler);
 126 }
 127
 128 // Note, this method only returns variables set on the executable load command, not those from the environment
 129 void PathOverrides::forEachExecutableEnvVar(void (^handler)(const char* envVar)) const
 130 {
 131     handleEnvVar("DYLD_LIBRARY_PATH",            _dylibPathOverridesExeLC,        handler);
 132     handleEnvVar("DYLD_FRAMEWORK_PATH",          _frameworkPathOverridesExeLC,    handler);
 133     handleEnvVar("DYLD_FALLBACK_FRAMEWORK_PATH", _frameworkPathFallbacksExeLC,    handler);
 134     handleEnvVar("DYLD_FALLBACK_LIBRARY_PATH",   _dylibPathFallbacksExeLC,        handler);
 135 }
 136
 137 const char* PathOverrides::addString(const char* str)
 138 {
 139     if ( _pathPool == nullptr )
 140         _pathPool = PathPool::allocate();
 141     return _pathPool->add(str);
 142 }
 143
 144 void PathOverrides::setString(const char*& var, const char* value)
 145 {
 146     if ( var == nullptr ) {
 147         var = addString(value);
 148         return;
 149     }
 150     // string already in use, build new appended string
 151     char tmp[strlen(var)+strlen(value)+2];
 152     strcpy(tmp, var);
 153     strcat(tmp, ":");
 154     strcat(tmp, value);
 155     var = addString(tmp);
 156 }
 157
 158 void PathOverrides::addEnvVar(const char* keyEqualsValue, bool forExecutable)
 159 {
 160     // We have to make a copy of the env vars because the dyld
 161     // semantics is that the env vars are only looked at once
 162     // at launch (using setenv() at runtime does not change dyld behavior).
 163     const char* equals = strchr(keyEqualsValue, '=');
 164     if ( equals != NULL ) {
 165         if ( strncmp(keyEqualsValue, "DYLD_LIBRARY_PATH", 17) == 0 ) {
 166             setString(forExecutable ? _dylibPathOverridesExeLC : _dylibPathOverridesEnv, &keyEqualsValue[18]);
 167         }
 168         else if ( strncmp(keyEqualsValue, "DYLD_FRAMEWORK_PATH", 19) == 0 ) {
 169             setString(forExecutable ? _frameworkPathOverridesExeLC : _frameworkPathOverridesEnv, &keyEqualsValue[20]);
 170         }
 171         else if ( strncmp(keyEqualsValue, "DYLD_FALLBACK_FRAMEWORK_PATH", 28) == 0 ) {
 172             setString(forExecutable ? _frameworkPathFallbacksExeLC : _frameworkPathFallbacksEnv, &keyEqualsValue[29]);
 173         }
 174         else if ( strncmp(keyEqualsValue, "DYLD_FALLBACK_LIBRARY_PATH", 26) == 0 ) {
 175             setString(forExecutable ? _dylibPathFallbacksExeLC : _dylibPathFallbacksEnv, &keyEqualsValue[27]);
 176         }
 177         else if ( strncmp(keyEqualsValue, "DYLD_INSERT_LIBRARIES", 21) == 0 ) {
 178             setString(_insertedDylibs, &keyEqualsValue[22]);
 179         }
 180         else if ( strncmp(keyEqualsValue, "DYLD_IMAGE_SUFFIX", 17) == 0 ) {
 181             setString(_imageSuffix, &keyEqualsValue[18]);
 182         }
 183         else if ( strncmp(keyEqualsValue, "DYLD_ROOT_PATH", 14) == 0 ) {
 184             setString(_rootPath, &keyEqualsValue[15]);
 185         }
 186     }
 187 }
 188
 189 void PathOverrides::forEachInColonList(const char* list1, const char* list2, void (^handler)(const char* path, bool& stop))
 190 {
 191     for (const char* list : { list1, list2 }) {
 192         if (list == nullptr)
 193             continue;
 194         char buffer[strlen(list)+1];
 195         const char* t = list;
 196         bool stop = false;
 197         for (const char* s=list; *s != '\0'; ++s) {
 198             if (*s != ':')
 199                 continue;
 200             size_t len = s - t;
 201             memcpy(buffer, t, len);
 202             buffer[len] = '\0';
 203             handler(buffer, stop);
 204             if ( stop )
 205                 return;
 206             t = s+1;
 207         }
 208         handler(t, stop);
 209         if (stop)
 210             return;
 211     }
 212 }
 213
 214 void PathOverrides::forEachDylibFallback(Platform platform, void (^handler)(const char* fallbackDir, bool& stop)) const
 215 {
 216     __block bool stop = false;
 217     if ( (_dylibPathFallbacksEnv != nullptr) || (_dylibPathFallbacksExeLC != nullptr) ) {
 218         forEachInColonList(_dylibPathFallbacksEnv, _dylibPathFallbacksExeLC, ^(const char* pth, bool& innerStop) {
 219             handler(pth, innerStop);
 220             if ( innerStop )
 221                 stop = true;
 222         });
 223     }
 224     else {
 225         switch ( platform ) {
 226             case Platform::macOS:
 227                 switch ( _fallbackPathMode ) {
 228                     case FallbackPathMode::classic:
 229                         // "$HOME/lib"
 230                         handler("/usr/local/lib", stop);
 231                         if ( stop )
 232                             break;
 233                         [[clang::fallthrough]];
 234                     case FallbackPathMode::restricted:
 235                         handler("/usr/lib", stop);
 236                         break;
 237                     case FallbackPathMode::none:
 238                         break;
 239                 }
 240                 break;
 241             case Platform::iOS:
 242             case Platform::watchOS:
 243             case Platform::tvOS:
 244             case Platform::bridgeOS:
 245             case Platform::driverKit:
 246             case Platform::unknown:
 247                 if ( _fallbackPathMode != FallbackPathMode::none ) {
 248                     handler("/usr/local/lib", stop);
 249                     if ( stop )
 250                         break;
 251                 }
 252                 // fall into /usr/lib case
 253                 [[clang::fallthrough]];
 254             case Platform::iOSMac:
 255             case Platform::iOS_simulator:
 256             case Platform::watchOS_simulator:
 257             case Platform::tvOS_simulator:
 258                 if ( _fallbackPathMode != FallbackPathMode::none )
 259                     handler("/usr/lib", stop);
 260                 break;
 261         }
 262     }
 263 }
 264
 265 void PathOverrides::forEachFrameworkFallback(Platform platform, void (^handler)(const char* fallbackDir, bool& stop)) const
 266 {
 267     __block bool stop = false;
 268     if ( (_frameworkPathFallbacksEnv != nullptr) || (_frameworkPathFallbacksExeLC != nullptr) ) {
 269         forEachInColonList(_frameworkPathFallbacksEnv, _frameworkPathFallbacksExeLC, ^(const char* pth, bool& innerStop) {
 270             handler(pth, innerStop);
 271             if ( innerStop )
 272                 stop = true;
 273         });
 274     }
 275     else {
 276         switch ( platform ) {
 277             case Platform::macOS:
 278                 switch ( _fallbackPathMode ) {
 279                     case FallbackPathMode::classic:
 280                         // "$HOME/Library/Frameworks"
 281                         handler("/Library/Frameworks", stop);
 282                         if ( stop )
 283                             break;
 284                         // "/Network/Library/Frameworks"
 285                         // fall thru
 286                         [[clang::fallthrough]];
 287                     case FallbackPathMode::restricted:
 288                         handler("/System/Library/Frameworks", stop);
 289                         break;
 290                     case FallbackPathMode::none:
 291                         break;
 292                 }
 293                 break;
 294             case Platform::iOS:
 295             case Platform::watchOS:
 296             case Platform::tvOS:
 297             case Platform::bridgeOS:
 298             case Platform::iOSMac:
 299             case Platform::iOS_simulator:
 300             case Platform::watchOS_simulator:
 301             case Platform::tvOS_simulator:
 302             case Platform::driverKit:
 303             case Platform::unknown:
 304                 if ( _fallbackPathMode != FallbackPathMode::none )
 305                     handler("/System/Library/Frameworks", stop);
 306                 break;
 307         }
 308     }
 309 }
 310
 311
 312 //
 313 // copy path and add suffix to result
 314 //
 315 //  /path/foo.dylib      _debug   =>   /path/foo_debug.dylib
 316 //  foo.dylib            _debug   =>   foo_debug.dylib
 317 //  foo                  _debug   =>   foo_debug
 318 //  /path/bar            _debug   =>   /path/bar_debug
 319 //  /path/bar.A.dylib    _debug   =>   /path/bar.A_debug.dylib
 320 //
 321 void PathOverrides::addSuffix(const char* path, const char* suffix, char* result) const
 322 {
 323     strcpy(result, path);
 324
 325     // find last slash
 326     char* start = strrchr(result, '/');
 327     if ( start != NULL )
 328         start++;
 329     else
 330         start = result;
 331
 332     // find last dot after last slash
 333     char* dot = strrchr(start, '.');
 334     if ( dot != NULL ) {
 335         strcpy(dot, suffix);
 336         strcat(&dot[strlen(suffix)], &path[dot-result]);
 337     }
 338     else {
 339         strcat(result, suffix);
 340     }
 341 }
 342
 343 void PathOverrides::forEachImageSuffix(const char* path, bool isFallbackPath, bool pathIsInDyldCacheWhichCannotBeOverridden, bool& stop, void (^handler)(const char* possiblePath, bool isFallbackPath, bool& stop)) const
 344 {
 345     if ( (_imageSuffix == nullptr) || pathIsInDyldCacheWhichCannotBeOverridden ) {
 346         handler(path, isFallbackPath, stop);
 347     }
 348     else {
 349         forEachInColonList(_imageSuffix, nullptr, ^(const char* suffix, bool& innerStop) {
 350             char npath[strlen(path)+strlen(suffix)+8];
 351             addSuffix(path, suffix, npath);
 352             handler(npath, isFallbackPath, innerStop);
 353             if ( innerStop )
 354                 stop = true;
 355         });
 356         if ( !stop )
 357             handler(path, isFallbackPath, stop);
 358     }
 359 }
 360
 361 void PathOverrides::forEachPathVariant(const char* initialPath, bool pathIsInDyldCacheWhichCannotBeOverridden, void (^handler)(const char* possiblePath, bool isFallbackPath, bool& stop), Platform platform) const
 362 {
 363     __block bool stop = false;
 364
 365
 366     if ( !pathIsInDyldCacheWhichCannotBeOverridden ) {
 367         // check for overrides
 368         const char* frameworkPartialPath = getFrameworkPartialPath(initialPath);
 369         if ( frameworkPartialPath != nullptr ) {
 370             const size_t frameworkPartialPathLen = strlen(frameworkPartialPath);
 371             // look at each DYLD_FRAMEWORK_PATH directory
 372             if ( (_frameworkPathOverridesEnv != nullptr) || (_frameworkPathOverridesExeLC != nullptr) ) {
 373                 forEachInColonList(_frameworkPathOverridesEnv, _frameworkPathOverridesExeLC, ^(const char* frDir, bool &innerStop) {
 374                     char npath[strlen(frDir)+frameworkPartialPathLen+8];
 375                     strcpy(npath, frDir);
 376                     strcat(npath, "/");
 377                     strcat(npath, frameworkPartialPath);
 378                     forEachImageSuffix(npath, false, pathIsInDyldCacheWhichCannotBeOverridden, innerStop, handler);
 379                     if ( innerStop )
 380                         stop = true;
 381                 });
 382             }
 383         }
 384         else {
 385             const char* libraryLeafName = getLibraryLeafName(initialPath);
 386             const size_t libraryLeafNameLen = strlen(libraryLeafName);
 387             // look at each DYLD_LIBRARY_PATH directory
 388             if ( (_dylibPathOverridesEnv != nullptr) || (_dylibPathOverridesExeLC != nullptr) ) {
 389                 forEachInColonList(_dylibPathOverridesEnv, _dylibPathOverridesExeLC, ^(const char* libDir, bool &innerStop) {
 390                     char npath[strlen(libDir)+libraryLeafNameLen+8];
 391                     strcpy(npath, libDir);
 392                     strcat(npath, "/");
 393                     strcat(npath, libraryLeafName);
 394                     forEachImageSuffix(npath, false, pathIsInDyldCacheWhichCannotBeOverridden, innerStop, handler);
 395                     if ( innerStop )
 396                         stop = true;
 397                 });
 398             }
 399         }
 400         if ( stop )
 401             return;
 402     }
 403
 404     // try original path
 405     forEachImageSuffix(initialPath, false, pathIsInDyldCacheWhichCannotBeOverridden, stop, handler);
 406     if ( stop )
 407         return;
 408
 409     // check fallback paths
 410     if ( const char* frameworkPartialPath = getFrameworkPartialPath(initialPath) ) {
 411         const size_t frameworkPartialPathLen = strlen(frameworkPartialPath);
 412         // look at each DYLD_FALLBACK_FRAMEWORK_PATH directory
 413         bool usesDefaultFallbackPaths = (_frameworkPathFallbacksEnv == nullptr) && (_frameworkPathFallbacksExeLC == nullptr);
 414         forEachFrameworkFallback(platform, ^(const char* dir, bool& innerStop) {
 415             char npath[strlen(dir)+frameworkPartialPathLen+8];
 416             strcpy(npath, dir);
 417             strcat(npath, "/");
 418             strcat(npath, frameworkPartialPath);
 419             forEachImageSuffix(npath, usesDefaultFallbackPaths, pathIsInDyldCacheWhichCannotBeOverridden, innerStop, handler);
 420             if ( innerStop )
 421                 stop = true;
 422         });
 423
 424     }
 425    else {
 426         const char* libraryLeafName = getLibraryLeafName(initialPath);
 427         const size_t libraryLeafNameLen = strlen(libraryLeafName);
 428         // look at each DYLD_FALLBACK_LIBRARY_PATH directory
 429         bool usesDefaultFallbackPaths = (_dylibPathFallbacksEnv == nullptr) && (_dylibPathFallbacksExeLC == nullptr);
 430         forEachDylibFallback(platform, ^(const char* dir, bool& innerStop) {
 431             char libpath[strlen(dir)+libraryLeafNameLen+8];
 432             strcpy(libpath, dir);
 433             strcat(libpath, "/");
 434             strcat(libpath, libraryLeafName);
 435             forEachImageSuffix(libpath, usesDefaultFallbackPaths, pathIsInDyldCacheWhichCannotBeOverridden, innerStop, handler);
 436             if ( innerStop )
 437                 stop = true;
 438         });
 439     }
 440 }
 441
 442
 443 //
 444 // Find framework path
 445 //
 446 //  /path/foo.framework/foo                             =>   foo.framework/foo
 447 //  /path/foo.framework/Versions/A/foo                  =>   foo.framework/Versions/A/foo
 448 //  /path/foo.framework/Frameworks/bar.framework/bar    =>   bar.framework/bar
 449 //  /path/foo.framework/Libraries/bar.dylb              =>   NULL
 450 //  /path/foo.framework/bar                             =>   NULL
 451 //
 452 // Returns nullptr if not a framework path
 453 //
 454 const char* PathOverrides::getFrameworkPartialPath(const char* path) const
 455 {
 456     const char* dirDot = strrstr(path, ".framework/");
 457     if ( dirDot != nullptr ) {
 458         const char* dirStart = dirDot;
 459         for ( ; dirStart >= path; --dirStart) {
 460             if ( (*dirStart == '/') || (dirStart == path) ) {
 461                 const char* frameworkStart = &dirStart[1];
 462                 if ( dirStart == path )
 463                     --frameworkStart;
 464                 size_t len = dirDot - frameworkStart;
 465                 char framework[len+1];
 466                 strncpy(framework, frameworkStart, len);
 467                 framework[len] = '\0';
 468                 const char* leaf = strrchr(path, '/');
 469                 if ( leaf != nullptr ) {
 470                     if ( strcmp(framework, &leaf[1]) == 0 ) {
 471                         return frameworkStart;
 472                     }
 473                     if (  _imageSuffix != nullptr ) {
 474                         // some debug frameworks have install names that end in _debug
 475                         if ( strncmp(framework, &leaf[1], len) == 0 ) {
 476                             if ( strcmp( _imageSuffix, &leaf[len+1]) == 0 )
 477                                 return frameworkStart;
 478                         }
 479                     }
 480                 }
 481             }
 482         }
 483     }
 484     return nullptr;
 485 }
 486
 487
 488 const char* PathOverrides::getLibraryLeafName(const char* path)
 489 {
 490     const char* start = strrchr(path, '/');
 491     if ( start != nullptr )
 492         return &start[1];
 493     else
 494         return path;
 495 }
 496
 497
 498
 499 ////////////////////////////  PathPool ////////////////////////////////////////
 500
 501
 502 PathPool* PathPool::allocate()
 503 {
 504     vm_address_t addr;
 505     ::vm_allocate(mach_task_self(), &addr, kAllocationSize, VM_FLAGS_ANYWHERE);
 506     PathPool* p = (PathPool*)addr;
 507     p->_next      = nullptr;
 508     p->_current   = &(p->_buffer[0]);
 509     p->_bytesFree = kAllocationSize - sizeof(PathPool);
 510     return p;
 511 }
 512
 513 void PathPool::deallocate(PathPool* pool) {
 514     do {
 515         PathPool* next = pool->_next;
 516         ::vm_deallocate(mach_task_self(), (vm_address_t)pool, kAllocationSize);
 517         pool = next;
 518     } while (pool);
 519 }
 520
 521 const char* PathPool::add(const char* path)
 522 {
 523     size_t len = strlen(path) + 1;
 524     if ( len < _bytesFree ) {
 525         char* result = _current;
 526         strcpy(_current, path);
 527         _current += len;
 528         _bytesFree -= len;
 529         return result;
 530     }
 531     if ( _next == nullptr )
 532         _next = allocate();
 533     return _next->add(path);
 534 }
 535
 536 void PathPool::forEachPath(void (^handler)(const char* path))
 537 {
 538     for (const char* s = _buffer; s < _current; ++s) {
 539         handler(s);
 540         s += strlen(s);
 541     }
 542
 543     if ( _next != nullptr )
 544         _next->forEachPath(handler);
 545 }
 546
 547
 548
 549 } // namespace closure
 550 } // namespace dyld3
 551
 552
 553
 554
 555