sys/external/bsd/compiler_rt/dist/lib/lsan/lsan_common_linux.cc

   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
  25 namespace __lsan {
  26
  27 static 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.
  30 static char linker_placeholder[2 * sizeof(LoadedModule)] ALIGNED(64);
  31 static LoadedModule *linker = 0;
  32
  33 static bool IsLinker(const char* full_name) {
  34   return LibraryNameIs(full_name, kLinkerName);
  35 }
  36
  37 void 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
  54 static int ProcessGlobalRegionsCallback(struct dl_phdr_info *info, size_t size,
  55                                         void *data) {
  56   Frontier *frontier = reinterpret_cast<Frontier *>(data);
  57   for (uptr j = 0; j < info->dlpi_phnum; j++) {
  58     const ElfW(Phdr) *phdr = &(info->dlpi_phdr[j]);
  59     // We're looking for .data and .bss sections, which reside in writeable,
  60     // loadable segments.
  61     if (!(phdr->p_flags & PF_W) || (phdr->p_type != PT_LOAD) ||
  62         (phdr->p_memsz == 0))
  63       continue;
  64     uptr begin = info->dlpi_addr + phdr->p_vaddr;
  65     uptr end = begin + phdr->p_memsz;
  66     uptr allocator_begin = 0, allocator_end = 0;
  67     GetAllocatorGlobalRange(&allocator_begin, &allocator_end);
  68     if (begin <= allocator_begin && allocator_begin < end) {
  69       CHECK_LE(allocator_begin, allocator_end);
  70       CHECK_LT(allocator_end, end);
  71       if (begin < allocator_begin)
  72         ScanRangeForPointers(begin, allocator_begin, frontier, "GLOBAL",
  73                              kReachable);
  74       if (allocator_end < end)
  75         ScanRangeForPointers(allocator_end, end, frontier, "GLOBAL",
  76                              kReachable);
  77     } else {
  78       ScanRangeForPointers(begin, end, frontier, "GLOBAL", kReachable);
  79     }
  80   }
  81   return 0;
  82 }
  83
  84 // Scans global variables for heap pointers.
  85 void ProcessGlobalRegions(Frontier *frontier) {
  86   // FIXME: dl_iterate_phdr acquires a linker lock, so we run a risk of
  87   // deadlocking by running this under StopTheWorld. However, the lock is
  88   // reentrant, so we should be able to fix this by acquiring the lock before
  89   // suspending threads.
  90   dl_iterate_phdr(ProcessGlobalRegionsCallback, frontier);
  91 }
  92
  93 static uptr GetCallerPC(u32 stack_id) {
  94   CHECK(stack_id);
  95   uptr size = 0;
  96   const uptr *trace = StackDepotGet(stack_id, &size);
  97   // The top frame is our malloc/calloc/etc. The next frame is the caller.
  98   if (size >= 2)
  99     return trace[1];
 100   return 0;
 101 }
 102
 103 // ForEachChunk callback. Identifies unreachable chunks which must be treated as
 104 // reachable. Marks them as reachable and adds them to the frontier.
 105 static void ProcessPlatformSpecificAllocationsCb(uptr chunk, void *arg) {
 106   CHECK(arg);
 107   chunk = GetUserBegin(chunk);
 108   LsanMetadata m(chunk);
 109   if (m.allocated() && m.tag() != kReachable) {
 110     if (linker->containsAddress(GetCallerPC(m.stack_trace_id()))) {
 111       m.set_tag(kReachable);
 112       reinterpret_cast<Frontier *>(arg)->push_back(chunk);
 113     }
 114   }
 115 }
 116
 117 // Handles dynamically allocated TLS blocks by treating all chunks allocated
 118 // from ld-linux.so as reachable.
 119 void ProcessPlatformSpecificAllocations(Frontier *frontier) {
 120   if (!flags()->use_tls) return;
 121   if (!linker) return;
 122   ForEachChunk(ProcessPlatformSpecificAllocationsCb, frontier);
 123 }
 124
 125 }  // namespace __lsan
 126 #endif  // CAN_SANITIZE_LEAKS && SANITIZER_LINUX