lsan_common_linux.cc revision 9bdf7802d403b53baee3433ddddc220f457e039c
1//=-- lsan_common_linux.cc ------------------------------------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file is a part of LeakSanitizer. 11// Implementation of common leak checking functionality. Linux-specific code. 12// 13//===----------------------------------------------------------------------===// 14 15#include "sanitizer_common/sanitizer_platform.h" 16#include "lsan_common.h" 17 18#if CAN_SANITIZE_LEAKS && SANITIZER_LINUX 19#include <link.h> 20 21#include "sanitizer_common/sanitizer_common.h" 22#include "sanitizer_common/sanitizer_linux.h" 23#include "sanitizer_common/sanitizer_stackdepot.h" 24 25namespace __lsan { 26 27static const char kLinkerName[] = "ld"; 28// We request 2 modules matching "ld", so we can print a warning if there's more 29// than one match. But only the first one is actually used. 30static char linker_placeholder[2 * sizeof(LoadedModule)] ALIGNED(64); 31static LoadedModule *linker = 0; 32 33static bool IsLinker(const char* full_name) { 34 return LibraryNameIs(full_name, kLinkerName); 35} 36 37void InitializePlatformSpecificModules() { 38 internal_memset(linker_placeholder, 0, sizeof(linker_placeholder)); 39 uptr num_matches = GetListOfModules( 40 reinterpret_cast<LoadedModule *>(linker_placeholder), 2, IsLinker); 41 if (num_matches == 1) { 42 linker = reinterpret_cast<LoadedModule *>(linker_placeholder); 43 return; 44 } 45 if (num_matches == 0) 46 Report("%s: Dynamic linker not found. TLS will not be handled correctly.\n", 47 SanitizerToolName); 48 else if (num_matches > 1) 49 Report("%s: Multiple modules match \"%s\". TLS will not be handled " 50 "correctly.\n", SanitizerToolName, kLinkerName); 51 linker = 0; 52} 53 54static int ProcessGlobalRegionsCallback(struct dl_phdr_info *info, size_t size, 55 void *data) { 56 InternalVector<uptr> *frontier = 57 reinterpret_cast<InternalVector<uptr> *>(data); 58 for (uptr j = 0; j < info->dlpi_phnum; j++) { 59 const ElfW(Phdr) *phdr = &(info->dlpi_phdr[j]); 60 // We're looking for .data and .bss sections, which reside in writeable, 61 // loadable segments. 62 if (!(phdr->p_flags & PF_W) || (phdr->p_type != PT_LOAD) || 63 (phdr->p_memsz == 0)) 64 continue; 65 uptr begin = info->dlpi_addr + phdr->p_vaddr; 66 uptr end = begin + phdr->p_memsz; 67 uptr allocator_begin = 0, allocator_end = 0; 68 GetAllocatorGlobalRange(&allocator_begin, &allocator_end); 69 if (begin <= allocator_begin && allocator_begin < end) { 70 CHECK_LE(allocator_begin, allocator_end); 71 CHECK_LT(allocator_end, end); 72 if (begin < allocator_begin) 73 ScanRangeForPointers(begin, allocator_begin, frontier, "GLOBAL", 74 kReachable); 75 if (allocator_end < end) 76 ScanRangeForPointers(allocator_end, end, frontier, "GLOBAL", 77 kReachable); 78 } else { 79 ScanRangeForPointers(begin, end, frontier, "GLOBAL", kReachable); 80 } 81 } 82 return 0; 83} 84 85// Scan global variables for heap pointers. 86void ProcessGlobalRegions(InternalVector<uptr> *frontier) { 87 // FIXME: dl_iterate_phdr acquires a linker lock, so we run a risk of 88 // deadlocking by running this under StopTheWorld. However, the lock is 89 // reentrant, so we should be able to fix this by acquiring the lock before 90 // suspending threads. 91 dl_iterate_phdr(ProcessGlobalRegionsCallback, frontier); 92} 93 94static uptr GetCallerPC(u32 stack_id) { 95 CHECK(stack_id); 96 uptr size = 0; 97 const uptr *trace = StackDepotGet(stack_id, &size); 98 // The top frame is our malloc/calloc/etc. The next frame is the caller. 99 CHECK_GE(size, 2); 100 return trace[1]; 101} 102 103void ProcessPlatformSpecificAllocationsCb::operator()(void *p) const { 104 p = GetUserBegin(p); 105 LsanMetadata m(p); 106 if (m.allocated() && m.tag() != kReachable) { 107 if (linker->containsAddress(GetCallerPC(m.stack_trace_id()))) { 108 m.set_tag(kReachable); 109 frontier_->push_back(reinterpret_cast<uptr>(p)); 110 } 111 } 112} 113 114// Handle dynamically allocated TLS blocks by treating all chunks allocated from 115// ld-linux.so as reachable. 116void ProcessPlatformSpecificAllocations(InternalVector<uptr> *frontier) { 117 if (!flags()->use_tls()) return; 118 if (!linker) return; 119 ForEachChunk(ProcessPlatformSpecificAllocationsCb(frontier)); 120} 121 122} // namespace __lsan 123#endif // CAN_SANITIZE_LEAKS && SANITIZER_LINUX 124