240 lines · 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-exception6//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_APPLE19 20# include <mach/mach.h>21# include <mach/vm_statistics.h>22# include <pthread.h>23 24# include "lsan_allocator.h"25# include "sanitizer_common/sanitizer_allocator_internal.h"26namespace __lsan {27 28class ThreadContextLsanBase;29 30enum class SeenRegion {31 None = 0,32 AllocOnce = 1 << 0,33 LibDispatch = 1 << 1,34 Foundation = 1 << 2,35 All = AllocOnce | LibDispatch | Foundation36};37 38inline SeenRegion operator|(SeenRegion left, SeenRegion right) {39 return static_cast<SeenRegion>(static_cast<int>(left) |40 static_cast<int>(right));41}42 43inline SeenRegion &operator|=(SeenRegion &left, const SeenRegion &right) {44 left = left | right;45 return left;46}47 48struct RegionScanState {49 SeenRegion seen_regions = SeenRegion::None;50 bool in_libdispatch = false;51};52 53typedef struct {54 int disable_counter;55 ThreadContextLsanBase *current_thread;56 AllocatorCache cache;57} thread_local_data_t;58 59static pthread_key_t key;60static pthread_once_t key_once = PTHREAD_ONCE_INIT;61 62// The main thread destructor requires the current thread,63// so we can't destroy it until it's been used and reset.64void restore_tid_data(void *ptr) {65 thread_local_data_t *data = (thread_local_data_t *)ptr;66 if (data->current_thread)67 pthread_setspecific(key, data);68}69 70static void make_tls_key() {71 CHECK_EQ(pthread_key_create(&key, restore_tid_data), 0);72}73 74static thread_local_data_t *get_tls_val(bool alloc) {75 pthread_once(&key_once, make_tls_key);76 77 thread_local_data_t *ptr = (thread_local_data_t *)pthread_getspecific(key);78 if (ptr == NULL && alloc) {79 ptr = (thread_local_data_t *)InternalAlloc(sizeof(*ptr));80 ptr->disable_counter = 0;81 ptr->current_thread = nullptr;82 ptr->cache = AllocatorCache();83 pthread_setspecific(key, ptr);84 }85 86 return ptr;87}88 89bool DisabledInThisThread() {90 thread_local_data_t *data = get_tls_val(false);91 return data ? data->disable_counter > 0 : false;92}93 94void DisableInThisThread() { ++get_tls_val(true)->disable_counter; }95 96void EnableInThisThread() {97 int *disable_counter = &get_tls_val(true)->disable_counter;98 if (*disable_counter == 0) {99 DisableCounterUnderflow();100 }101 --*disable_counter;102}103 104ThreadContextLsanBase *GetCurrentThread() {105 thread_local_data_t *data = get_tls_val(false);106 return data ? data->current_thread : nullptr;107}108 109void SetCurrentThread(ThreadContextLsanBase *tctx) {110 get_tls_val(true)->current_thread = tctx;111}112 113AllocatorCache *GetAllocatorCache() { return &get_tls_val(true)->cache; }114 115LoadedModule *GetLinker() { return nullptr; }116 117// Required on Linux for initialization of TLS behavior, but should not be118// required on Darwin.119void InitializePlatformSpecificModules() {}120 121// Sections which can't contain contain global pointers. This list errs on the122// side of caution to avoid false positives, at the expense of performance.123//124// Other potentially safe sections include:125// __all_image_info, __crash_info, __const, __got, __interpose, __objc_msg_break126//127// Sections which definitely cannot be included here are:128// __objc_data, __objc_const, __data, __bss, __common, __thread_data,129// __thread_bss, __thread_vars, __objc_opt_rw, __objc_opt_ptrs130static const char *kSkippedSecNames[] = {131 "__cfstring", "__la_symbol_ptr", "__mod_init_func",132 "__mod_term_func", "__nl_symbol_ptr", "__objc_classlist",133 "__objc_classrefs", "__objc_imageinfo", "__objc_nlclslist",134 "__objc_protolist", "__objc_selrefs", "__objc_superrefs"};135 136// Scans global variables for heap pointers.137void ProcessGlobalRegions(Frontier *frontier) {138 for (auto name : kSkippedSecNames)139 CHECK(internal_strnlen(name, kMaxSegName + 1) <= kMaxSegName);140 141 MemoryMappingLayout memory_mapping(false);142 InternalMmapVector<LoadedModule> modules;143 modules.reserve(128);144 memory_mapping.DumpListOfModules(&modules);145 for (uptr i = 0; i < modules.size(); ++i) {146 // Even when global scanning is disabled, we still need to scan147 // system libraries for stashed pointers148 if (!flags()->use_globals && modules[i].instrumented()) continue;149 150 for (const __sanitizer::LoadedModule::AddressRange &range :151 modules[i].ranges()) {152 // Sections storing global variables are writable and non-executable153 if (range.executable || !range.writable) continue;154 155 for (auto name : kSkippedSecNames) {156 if (!internal_strcmp(range.name, name)) continue;157 }158 159 ScanGlobalRange(range.beg, range.end, frontier);160 }161 }162}163 164void ProcessPlatformSpecificAllocations(Frontier *frontier) {165 vm_address_t address = 0;166 kern_return_t err = KERN_SUCCESS;167 168 InternalMmapVector<Region> mapped_regions;169 bool use_root_regions = flags()->use_root_regions && HasRootRegions();170 171 RegionScanState scan_state;172 while (err == KERN_SUCCESS) {173 vm_size_t size = 0;174 unsigned depth = 1;175 struct vm_region_submap_info_64 info;176 mach_msg_type_number_t count = VM_REGION_SUBMAP_INFO_COUNT_64;177 err = vm_region_recurse_64(mach_task_self(), &address, &size, &depth,178 (vm_region_info_t)&info, &count);179 180 uptr end_address = address + size;181 if (info.user_tag == VM_MEMORY_OS_ALLOC_ONCE) {182 // libxpc stashes some pointers in the Kernel Alloc Once page,183 // make sure not to report those as leaks.184 scan_state.seen_regions |= SeenRegion::AllocOnce;185 ScanRangeForPointers(address, end_address, frontier, "GLOBAL",186 kReachable);187 } else if (info.user_tag == VM_MEMORY_FOUNDATION) {188 // Objective-C block trampolines use the Foundation region.189 scan_state.seen_regions |= SeenRegion::Foundation;190 ScanRangeForPointers(address, end_address, frontier, "GLOBAL",191 kReachable);192 } else if (info.user_tag == VM_MEMORY_LIBDISPATCH) {193 // Dispatch continuations use the libdispatch region. Empirically, there194 // can be more than one region with this tag, so we'll optimistically195 // assume that they're continguous. Otherwise, we would need to scan every196 // region to ensure we find them all.197 scan_state.in_libdispatch = true;198 ScanRangeForPointers(address, end_address, frontier, "GLOBAL",199 kReachable);200 } else if (scan_state.in_libdispatch) {201 scan_state.seen_regions |= SeenRegion::LibDispatch;202 scan_state.in_libdispatch = false;203 }204 205 // Recursing over the full memory map is very slow, break out206 // early if we don't need the full iteration.207 if (scan_state.seen_regions == SeenRegion::All && !use_root_regions) {208 break;209 }210 211 // This additional root region scan is required on Darwin in order to212 // detect root regions contained within mmap'd memory regions, because213 // the Darwin implementation of sanitizer_procmaps traverses images214 // as loaded by dyld, and not the complete set of all memory regions.215 //216 // TODO(fjricci) - remove this once sanitizer_procmaps_mac has the same217 // behavior as sanitizer_procmaps_linux and traverses all memory regions218 if (use_root_regions && (info.protection & kProtectionRead))219 mapped_regions.push_back({address, end_address});220 221 address = end_address;222 }223 ScanRootRegions(frontier, mapped_regions);224}225 226// On darwin, we can intercept _exit gracefully, and return a failing exit code227// if required at that point. Calling Die() here is undefined behavior and228// causes rare race conditions.229void HandleLeaks() {}230 231void LockStuffAndStopTheWorld(StopTheWorldCallback callback,232 CheckForLeaksParam *argument) {233 ScopedStopTheWorldLock lock;234 StopTheWorld(callback, argument);235}236 237} // namespace __lsan238 239#endif // CAN_SANITIZE_LEAKS && SANITIZER_APPLE240