libsanitizer/lsan/lsan_common_mac.cc

   1 //=-- lsan_common_mac.cc --------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of LeakSanitizer.
   9 // Implementation of common leak checking functionality. Darwin-specific code.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_common/sanitizer_platform.h"
  14 #include "lsan_common.h"
  15
  16 #if CAN_SANITIZE_LEAKS && SANITIZER_MAC
  17
  18 #include "sanitizer_common/sanitizer_allocator_internal.h"
  19 #include "lsan_allocator.h"
  20
  21 #include <pthread.h>
  22
  23 #include <mach/mach.h>
  24
  25 // Only introduced in Mac OS X 10.9.
  26 #ifdef VM_MEMORY_OS_ALLOC_ONCE
  27 static const int kSanitizerVmMemoryOsAllocOnce = VM_MEMORY_OS_ALLOC_ONCE;
  28 #else
  29 static const int kSanitizerVmMemoryOsAllocOnce = 73;
  30 #endif
  31
  32 namespace __lsan {
  33
  34 typedef struct {
  35   int disable_counter;
  36   u32 current_thread_id;
  37   AllocatorCache cache;
  38 } thread_local_data_t;
  39
  40 static pthread_key_t key;
  41 static pthread_once_t key_once = PTHREAD_ONCE_INIT;
  42
  43 // The main thread destructor requires the current thread id,
  44 // so we can't destroy it until it's been used and reset to invalid tid
  45 void restore_tid_data(void *ptr) {
  46   thread_local_data_t *data = (thread_local_data_t *)ptr;
  47   if (data->current_thread_id != kInvalidTid)
  48     pthread_setspecific(key, data);
  49 }
  50
  51 static void make_tls_key() {
  52   CHECK_EQ(pthread_key_create(&key, restore_tid_data), 0);
  53 }
  54
  55 static thread_local_data_t *get_tls_val(bool alloc) {
  56   pthread_once(&key_once, make_tls_key);
  57
  58   thread_local_data_t *ptr = (thread_local_data_t *)pthread_getspecific(key);
  59   if (ptr == NULL && alloc) {
  60     ptr = (thread_local_data_t *)InternalAlloc(sizeof(*ptr));
  61     ptr->disable_counter = 0;
  62     ptr->current_thread_id = kInvalidTid;
  63     ptr->cache = AllocatorCache();
  64     pthread_setspecific(key, ptr);
  65   }
  66
  67   return ptr;
  68 }
  69
  70 bool DisabledInThisThread() {
  71   thread_local_data_t *data = get_tls_val(false);
  72   return data ? data->disable_counter > 0 : false;
  73 }
  74
  75 void DisableInThisThread() { ++get_tls_val(true)->disable_counter; }
  76
  77 void EnableInThisThread() {
  78   int *disable_counter = &get_tls_val(true)->disable_counter;
  79   if (*disable_counter == 0) {
  80     DisableCounterUnderflow();
  81   }
  82   --*disable_counter;
  83 }
  84
  85 u32 GetCurrentThread() {
  86   thread_local_data_t *data = get_tls_val(false);
  87   return data ? data->current_thread_id : kInvalidTid;
  88 }
  89
  90 void SetCurrentThread(u32 tid) { get_tls_val(true)->current_thread_id = tid; }
  91
  92 AllocatorCache *GetAllocatorCache() { return &get_tls_val(true)->cache; }
  93
  94 LoadedModule *GetLinker() { return nullptr; }
  95
  96 // Required on Linux for initialization of TLS behavior, but should not be
  97 // required on Darwin.
  98 void InitializePlatformSpecificModules() {}
  99
 100 // Sections which can't contain contain global pointers. This list errs on the
 101 // side of caution to avoid false positives, at the expense of performance.
 102 //
 103 // Other potentially safe sections include:
 104 // __all_image_info, __crash_info, __const, __got, __interpose, __objc_msg_break
 105 //
 106 // Sections which definitely cannot be included here are:
 107 // __objc_data, __objc_const, __data, __bss, __common, __thread_data,
 108 // __thread_bss, __thread_vars, __objc_opt_rw, __objc_opt_ptrs
 109 static const char *kSkippedSecNames[] = {
 110     "__cfstring",       "__la_symbol_ptr",  "__mod_init_func",
 111     "__mod_term_func",  "__nl_symbol_ptr",  "__objc_classlist",
 112     "__objc_classrefs", "__objc_imageinfo", "__objc_nlclslist",
 113     "__objc_protolist", "__objc_selrefs",   "__objc_superrefs"};
 114
 115 // Scans global variables for heap pointers.
 116 void ProcessGlobalRegions(Frontier *frontier) {
 117   for (auto name : kSkippedSecNames) CHECK(ARRAY_SIZE(name) < kMaxSegName);
 118
 119   MemoryMappingLayout memory_mapping(false);
 120   InternalMmapVector<LoadedModule> modules;
 121   modules.reserve(128);
 122   memory_mapping.DumpListOfModules(&modules);
 123   for (uptr i = 0; i < modules.size(); ++i) {
 124     // Even when global scanning is disabled, we still need to scan
 125     // system libraries for stashed pointers
 126     if (!flags()->use_globals && modules[i].instrumented()) continue;
 127
 128     for (const __sanitizer::LoadedModule::AddressRange &range :
 129          modules[i].ranges()) {
 130       // Sections storing global variables are writable and non-executable
 131       if (range.executable || !range.writable) continue;
 132
 133       for (auto name : kSkippedSecNames) {
 134         if (!internal_strcmp(range.name, name)) continue;
 135       }
 136
 137       ScanGlobalRange(range.beg, range.end, frontier);
 138     }
 139   }
 140 }
 141
 142 void ProcessPlatformSpecificAllocations(Frontier *frontier) {
 143   unsigned depth = 1;
 144   vm_size_t size = 0;
 145   vm_address_t address = 0;
 146   kern_return_t err = KERN_SUCCESS;
 147   mach_msg_type_number_t count = VM_REGION_SUBMAP_INFO_COUNT_64;
 148
 149   InternalMmapVector<RootRegion> const *root_regions = GetRootRegions();
 150
 151   while (err == KERN_SUCCESS) {
 152     struct vm_region_submap_info_64 info;
 153     err = vm_region_recurse_64(mach_task_self(), &address, &size, &depth,
 154                                (vm_region_info_t)&info, &count);
 155
 156     uptr end_address = address + size;
 157
 158     // libxpc stashes some pointers in the Kernel Alloc Once page,
 159     // make sure not to report those as leaks.
 160     if (info.user_tag == kSanitizerVmMemoryOsAllocOnce) {
 161       ScanRangeForPointers(address, end_address, frontier, "GLOBAL",
 162                            kReachable);
 163
 164       // Recursing over the full memory map is very slow, break out
 165       // early if we don't need the full iteration.
 166       if (!flags()->use_root_regions || !root_regions->size())
 167         break;
 168     }
 169
 170     // This additional root region scan is required on Darwin in order to
 171     // detect root regions contained within mmap'd memory regions, because
 172     // the Darwin implementation of sanitizer_procmaps traverses images
 173     // as loaded by dyld, and not the complete set of all memory regions.
 174     //
 175     // TODO(fjricci) - remove this once sanitizer_procmaps_mac has the same
 176     // behavior as sanitizer_procmaps_linux and traverses all memory regions
 177     if (flags()->use_root_regions) {
 178       for (uptr i = 0; i < root_regions->size(); i++) {
 179         ScanRootRegion(frontier, (*root_regions)[i], address, end_address,
 180                        info.protection & kProtectionRead);
 181       }
 182     }
 183
 184     address = end_address;
 185   }
 186 }
 187
 188 // On darwin, we can intercept _exit gracefully, and return a failing exit code
 189 // if required at that point. Calling Die() here is undefined behavior and
 190 // causes rare race conditions.
 191 void HandleLeaks() {}
 192
 193 void DoStopTheWorld(StopTheWorldCallback callback, void *argument) {
 194   StopTheWorld(callback, argument);
 195 }
 196
 197 } // namespace __lsan
 198
 199 #endif // CAN_SANITIZE_LEAKS && SANITIZER_MAC