lsan_common_linux.cc revision 0550a3f9982ee7af5e16fa333f988d42b4cbf765 
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("LeakSanitizer: Dynamic linker not found. "
47           "TLS will not be handled correctly.\n");
48  else if (num_matches > 1)
49    Report("LeakSanitizer: Multiple modules match \"%s\". "
50           "TLS will not be handled correctly.\n", 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  if (size >= 2)
100    return trace[1];
101  return 0;
102}
103
104void ProcessPlatformSpecificAllocationsCb::operator()(void *p) const {
105  p = GetUserBegin(p);
106  LsanMetadata m(p);
107  if (m.allocated() && m.tag() != kReachable) {
108    if (linker->containsAddress(GetCallerPC(m.stack_trace_id()))) {
109      m.set_tag(kReachable);
110      frontier_->push_back(reinterpret_cast<uptr>(p));
111    }
112  }
113}
114
115// Handle dynamically allocated TLS blocks by treating all chunks allocated from
116// ld-linux.so as reachable.
117void ProcessPlatformSpecificAllocations(InternalVector<uptr> *frontier) {
118  if (!flags()->use_tls) return;
119  if (!linker) return;
120  ForEachChunk(ProcessPlatformSpecificAllocationsCb(frontier));
121}
122
123}  // namespace __lsan
124#endif  // CAN_SANITIZE_LEAKS && SANITIZER_LINUX
125