libsanitizer/lsan/lsan_common_mac.cpp

   1 //=-- lsan_common_mac.cpp -------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of LeakSanitizer.
  10 // Implementation of common leak checking functionality. Darwin-specific code.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "sanitizer_common/sanitizer_platform.h"
  15 #include "sanitizer_common/sanitizer_libc.h"
  16 #include "lsan_common.h"
  17
  18 #if CAN_SANITIZE_LEAKS && SANITIZER_APPLE
  19
  20 #include "sanitizer_common/sanitizer_allocator_internal.h"
  21 #include "lsan_allocator.h"
  22
  23 #include <pthread.h>
  24
  25 #include <mach/mach.h>
  26
  27 // Only introduced in Mac OS X 10.9.
  28 #ifdef VM_MEMORY_OS_ALLOC_ONCE
  29 static const int kSanitizerVmMemoryOsAllocOnce = VM_MEMORY_OS_ALLOC_ONCE;
  30 #else
  31 static const int kSanitizerVmMemoryOsAllocOnce = 73;
  32 #endif
  33
  34 namespace __lsan {
  35
  36 typedef struct {
  37   int disable_counter;
  38   u32 current_thread_id;
  39   AllocatorCache cache;
  40 } thread_local_data_t;
  41
  42 static pthread_key_t key;
  43 static pthread_once_t key_once = PTHREAD_ONCE_INIT;
  44
  45 // The main thread destructor requires the current thread id,
  46 // so we can't destroy it until it's been used and reset to invalid tid
  47 void restore_tid_data(void *ptr) {
  48   thread_local_data_t *data = (thread_local_data_t *)ptr;
  49   if (data->current_thread_id != kInvalidTid)
  50     pthread_setspecific(key, data);
  51 }
  52
  53 static void make_tls_key() {
  54   CHECK_EQ(pthread_key_create(&key, restore_tid_data), 0);
  55 }
  56
  57 static thread_local_data_t *get_tls_val(bool alloc) {
  58   pthread_once(&key_once, make_tls_key);
  59
  60   thread_local_data_t *ptr = (thread_local_data_t *)pthread_getspecific(key);
  61   if (ptr == NULL && alloc) {
  62     ptr = (thread_local_data_t *)InternalAlloc(sizeof(*ptr));
  63     ptr->disable_counter = 0;
  64     ptr->current_thread_id = kInvalidTid;
  65     ptr->cache = AllocatorCache();
  66     pthread_setspecific(key, ptr);
  67   }
  68
  69   return ptr;
  70 }
  71
  72 bool DisabledInThisThread() {
  73   thread_local_data_t *data = get_tls_val(false);
  74   return data ? data->disable_counter > 0 : false;
  75 }
  76
  77 void DisableInThisThread() { ++get_tls_val(true)->disable_counter; }
  78
  79 void EnableInThisThread() {
  80   int *disable_counter = &get_tls_val(true)->disable_counter;
  81   if (*disable_counter == 0) {
  82     DisableCounterUnderflow();
  83   }
  84   --*disable_counter;
  85 }
  86
  87 u32 GetCurrentThread() {
  88   thread_local_data_t *data = get_tls_val(false);
  89   return data ? data->current_thread_id : kInvalidTid;
  90 }
  91
  92 void SetCurrentThread(u32 tid) { get_tls_val(true)->current_thread_id = tid; }
  93
  94 AllocatorCache *GetAllocatorCache() { return &get_tls_val(true)->cache; }
  95
  96 LoadedModule *GetLinker() { return nullptr; }
  97
  98 // Required on Linux for initialization of TLS behavior, but should not be
  99 // required on Darwin.
 100 void InitializePlatformSpecificModules() {}
 101
 102 // Sections which can't contain contain global pointers. This list errs on the
 103 // side of caution to avoid false positives, at the expense of performance.
 104 //
 105 // Other potentially safe sections include:
 106 // __all_image_info, __crash_info, __const, __got, __interpose, __objc_msg_break
 107 //
 108 // Sections which definitely cannot be included here are:
 109 // __objc_data, __objc_const, __data, __bss, __common, __thread_data,
 110 // __thread_bss, __thread_vars, __objc_opt_rw, __objc_opt_ptrs
 111 static const char *kSkippedSecNames[] = {
 112     "__cfstring",       "__la_symbol_ptr",  "__mod_init_func",
 113     "__mod_term_func",  "__nl_symbol_ptr",  "__objc_classlist",
 114     "__objc_classrefs", "__objc_imageinfo", "__objc_nlclslist",
 115     "__objc_protolist", "__objc_selrefs",   "__objc_superrefs"};
 116
 117 // Scans global variables for heap pointers.
 118 void ProcessGlobalRegions(Frontier *frontier) {
 119   for (auto name : kSkippedSecNames)
 120     CHECK(internal_strnlen(name, kMaxSegName + 1) <= kMaxSegName);
 121
 122   MemoryMappingLayout memory_mapping(false);
 123   InternalMmapVector<LoadedModule> modules;
 124   modules.reserve(128);
 125   memory_mapping.DumpListOfModules(&modules);
 126   for (uptr i = 0; i < modules.size(); ++i) {
 127     // Even when global scanning is disabled, we still need to scan
 128     // system libraries for stashed pointers
 129     if (!flags()->use_globals && modules[i].instrumented()) continue;
 130
 131     for (const __sanitizer::LoadedModule::AddressRange &range :
 132          modules[i].ranges()) {
 133       // Sections storing global variables are writable and non-executable
 134       if (range.executable || !range.writable) continue;
 135
 136       for (auto name : kSkippedSecNames) {
 137         if (!internal_strcmp(range.name, name)) continue;
 138       }
 139
 140       ScanGlobalRange(range.beg, range.end, frontier);
 141     }
 142   }
 143 }
 144
 145 void ProcessPlatformSpecificAllocations(Frontier *frontier) {
 146   vm_address_t address = 0;
 147   kern_return_t err = KERN_SUCCESS;
 148
 149   InternalMmapVectorNoCtor<RootRegion> const *root_regions = GetRootRegions();
 150
 151   while (err == KERN_SUCCESS) {
 152     vm_size_t size = 0;
 153     unsigned depth = 1;
 154     struct vm_region_submap_info_64 info;
 155     mach_msg_type_number_t count = VM_REGION_SUBMAP_INFO_COUNT_64;
 156     err = vm_region_recurse_64(mach_task_self(), &address, &size, &depth,
 157                                (vm_region_info_t)&info, &count);
 158
 159     uptr end_address = address + size;
 160
 161     // libxpc stashes some pointers in the Kernel Alloc Once page,
 162     // make sure not to report those as leaks.
 163     if (info.user_tag == kSanitizerVmMemoryOsAllocOnce) {
 164       ScanRangeForPointers(address, end_address, frontier, "GLOBAL",
 165                            kReachable);
 166
 167       // Recursing over the full memory map is very slow, break out
 168       // early if we don't need the full iteration.
 169       if (!flags()->use_root_regions || !root_regions->size())
 170         break;
 171     }
 172
 173     // This additional root region scan is required on Darwin in order to
 174     // detect root regions contained within mmap'd memory regions, because
 175     // the Darwin implementation of sanitizer_procmaps traverses images
 176     // as loaded by dyld, and not the complete set of all memory regions.
 177     //
 178     // TODO(fjricci) - remove this once sanitizer_procmaps_mac has the same
 179     // behavior as sanitizer_procmaps_linux and traverses all memory regions
 180     if (flags()->use_root_regions) {
 181       for (uptr i = 0; i < root_regions->size(); i++) {
 182         ScanRootRegion(frontier, (*root_regions)[i], address, end_address,
 183                        info.protection & kProtectionRead);
 184       }
 185     }
 186
 187     address = end_address;
 188   }
 189 }
 190
 191 // On darwin, we can intercept _exit gracefully, and return a failing exit code
 192 // if required at that point. Calling Die() here is undefined behavior and
 193 // causes rare race conditions.
 194 void HandleLeaks() {}
 195
 196 void LockStuffAndStopTheWorld(StopTheWorldCallback callback,
 197                               CheckForLeaksParam *argument) {
 198   ScopedStopTheWorldLock lock;
 199   StopTheWorld(callback, argument);
 200 }
 201
 202 } // namespace __lsan
 203
 204 #endif // CAN_SANITIZE_LEAKS && SANITIZER_APPLE