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| //=-- lsan_common_mac.cpp -------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of LeakSanitizer.
// Implementation of common leak checking functionality. Darwin-specific code.
//
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_platform.h"
#include "sanitizer_common/sanitizer_libc.h"
#include "lsan_common.h"
#if CAN_SANITIZE_LEAKS && SANITIZER_MAC
#include "sanitizer_common/sanitizer_allocator_internal.h"
#include "lsan_allocator.h"
#include <pthread.h>
#include <mach/mach.h>
// Only introduced in Mac OS X 10.9.
#ifdef VM_MEMORY_OS_ALLOC_ONCE
static const int kSanitizerVmMemoryOsAllocOnce = VM_MEMORY_OS_ALLOC_ONCE;
#else
static const int kSanitizerVmMemoryOsAllocOnce = 73;
#endif
namespace __lsan {
typedef struct {
int disable_counter;
u32 current_thread_id;
AllocatorCache cache;
} thread_local_data_t;
static pthread_key_t key;
static pthread_once_t key_once = PTHREAD_ONCE_INIT;
// The main thread destructor requires the current thread id,
// so we can't destroy it until it's been used and reset to invalid tid
void restore_tid_data(void *ptr) {
thread_local_data_t *data = (thread_local_data_t *)ptr;
if (data->current_thread_id != kInvalidTid)
pthread_setspecific(key, data);
}
static void make_tls_key() {
CHECK_EQ(pthread_key_create(&key, restore_tid_data), 0);
}
static thread_local_data_t *get_tls_val(bool alloc) {
pthread_once(&key_once, make_tls_key);
thread_local_data_t *ptr = (thread_local_data_t *)pthread_getspecific(key);
if (ptr == NULL && alloc) {
ptr = (thread_local_data_t *)InternalAlloc(sizeof(*ptr));
ptr->disable_counter = 0;
ptr->current_thread_id = kInvalidTid;
ptr->cache = AllocatorCache();
pthread_setspecific(key, ptr);
}
return ptr;
}
bool DisabledInThisThread() {
thread_local_data_t *data = get_tls_val(false);
return data ? data->disable_counter > 0 : false;
}
void DisableInThisThread() { ++get_tls_val(true)->disable_counter; }
void EnableInThisThread() {
int *disable_counter = &get_tls_val(true)->disable_counter;
if (*disable_counter == 0) {
DisableCounterUnderflow();
}
--*disable_counter;
}
u32 GetCurrentThread() {
thread_local_data_t *data = get_tls_val(false);
return data ? data->current_thread_id : kInvalidTid;
}
void SetCurrentThread(u32 tid) { get_tls_val(true)->current_thread_id = tid; }
AllocatorCache *GetAllocatorCache() { return &get_tls_val(true)->cache; }
LoadedModule *GetLinker() { return nullptr; }
// Required on Linux for initialization of TLS behavior, but should not be
// required on Darwin.
void InitializePlatformSpecificModules() {}
// Sections which can't contain contain global pointers. This list errs on the
// side of caution to avoid false positives, at the expense of performance.
//
// Other potentially safe sections include:
// __all_image_info, __crash_info, __const, __got, __interpose, __objc_msg_break
//
// Sections which definitely cannot be included here are:
// __objc_data, __objc_const, __data, __bss, __common, __thread_data,
// __thread_bss, __thread_vars, __objc_opt_rw, __objc_opt_ptrs
static const char *kSkippedSecNames[] = {
"__cfstring", "__la_symbol_ptr", "__mod_init_func",
"__mod_term_func", "__nl_symbol_ptr", "__objc_classlist",
"__objc_classrefs", "__objc_imageinfo", "__objc_nlclslist",
"__objc_protolist", "__objc_selrefs", "__objc_superrefs"};
// Scans global variables for heap pointers.
void ProcessGlobalRegions(Frontier *frontier) {
for (auto name : kSkippedSecNames)
CHECK(internal_strnlen(name, kMaxSegName + 1) <= kMaxSegName);
MemoryMappingLayout memory_mapping(false);
InternalMmapVector<LoadedModule> modules;
modules.reserve(128);
memory_mapping.DumpListOfModules(&modules);
for (uptr i = 0; i < modules.size(); ++i) {
// Even when global scanning is disabled, we still need to scan
// system libraries for stashed pointers
if (!flags()->use_globals && modules[i].instrumented()) continue;
for (const __sanitizer::LoadedModule::AddressRange &range :
modules[i].ranges()) {
// Sections storing global variables are writable and non-executable
if (range.executable || !range.writable) continue;
for (auto name : kSkippedSecNames) {
if (!internal_strcmp(range.name, name)) continue;
}
ScanGlobalRange(range.beg, range.end, frontier);
}
}
}
void ProcessPlatformSpecificAllocations(Frontier *frontier) {
unsigned depth = 1;
vm_size_t size = 0;
vm_address_t address = 0;
kern_return_t err = KERN_SUCCESS;
mach_msg_type_number_t count = VM_REGION_SUBMAP_INFO_COUNT_64;
InternalMmapVector<RootRegion> const *root_regions = GetRootRegions();
while (err == KERN_SUCCESS) {
struct vm_region_submap_info_64 info;
err = vm_region_recurse_64(mach_task_self(), &address, &size, &depth,
(vm_region_info_t)&info, &count);
uptr end_address = address + size;
// libxpc stashes some pointers in the Kernel Alloc Once page,
// make sure not to report those as leaks.
if (info.user_tag == kSanitizerVmMemoryOsAllocOnce) {
ScanRangeForPointers(address, end_address, frontier, "GLOBAL",
kReachable);
// Recursing over the full memory map is very slow, break out
// early if we don't need the full iteration.
if (!flags()->use_root_regions || !root_regions->size())
break;
}
// This additional root region scan is required on Darwin in order to
// detect root regions contained within mmap'd memory regions, because
// the Darwin implementation of sanitizer_procmaps traverses images
// as loaded by dyld, and not the complete set of all memory regions.
//
// TODO(fjricci) - remove this once sanitizer_procmaps_mac has the same
// behavior as sanitizer_procmaps_linux and traverses all memory regions
if (flags()->use_root_regions) {
for (uptr i = 0; i < root_regions->size(); i++) {
ScanRootRegion(frontier, (*root_regions)[i], address, end_address,
info.protection & kProtectionRead);
}
}
address = end_address;
}
}
// On darwin, we can intercept _exit gracefully, and return a failing exit code
// if required at that point. Calling Die() here is undefined behavior and
// causes rare race conditions.
void HandleLeaks() {}
void LockStuffAndStopTheWorld(StopTheWorldCallback callback, void *argument) {
LockThreadRegistry();
LockAllocator();
StopTheWorld(callback, argument);
UnlockAllocator();
UnlockThreadRegistry();
}
} // namespace __lsan
#endif // CAN_SANITIZE_LEAKS && SANITIZER_MAC
|