libsanitizer/asan/asan_debugging.cc

   1 //===-- asan_debugging.cc -------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of AddressSanitizer, an address sanity checker.
   9 //
  10 // This file contains various functions that are generally useful to call when
  11 // using a debugger (LLDB, GDB).
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "asan_allocator.h"
  15 #include "asan_descriptions.h"
  16 #include "asan_flags.h"
  17 #include "asan_internal.h"
  18 #include "asan_mapping.h"
  19 #include "asan_report.h"
  20 #include "asan_thread.h"
  21
  22 namespace {
  23 using namespace __asan;
  24
  25 static void FindInfoForStackVar(uptr addr, const char *frame_descr, uptr offset,
  26                                 char *name, uptr name_size,
  27                                 uptr &region_address, uptr &region_size) {
  28   InternalMmapVector<StackVarDescr> vars(16);
  29   if (!ParseFrameDescription(frame_descr, &vars)) {
  30     return;
  31   }
  32
  33   for (uptr i = 0; i < vars.size(); i++) {
  34     if (offset <= vars[i].beg + vars[i].size) {
  35       // We use name_len + 1 because strlcpy will guarantee a \0 at the end, so
  36       // if we're limiting the copy due to name_len, we add 1 to ensure we copy
  37       // the whole name and then terminate with '\0'.
  38       internal_strlcpy(name, vars[i].name_pos,
  39                        Min(name_size, vars[i].name_len + 1));
  40       region_address = addr - (offset - vars[i].beg);
  41       region_size = vars[i].size;
  42       return;
  43     }
  44   }
  45 }
  46
  47 uptr AsanGetStack(uptr addr, uptr *trace, u32 size, u32 *thread_id,
  48                          bool alloc_stack) {
  49   AsanChunkView chunk = FindHeapChunkByAddress(addr);
  50   if (!chunk.IsValid()) return 0;
  51
  52   StackTrace stack(nullptr, 0);
  53   if (alloc_stack) {
  54     if (chunk.AllocTid() == kInvalidTid) return 0;
  55     stack = chunk.GetAllocStack();
  56     if (thread_id) *thread_id = chunk.AllocTid();
  57   } else {
  58     if (chunk.FreeTid() == kInvalidTid) return 0;
  59     stack = chunk.GetFreeStack();
  60     if (thread_id) *thread_id = chunk.FreeTid();
  61   }
  62
  63   if (trace && size) {
  64     size = Min(size, Min(stack.size, kStackTraceMax));
  65     for (uptr i = 0; i < size; i++)
  66       trace[i] = StackTrace::GetPreviousInstructionPc(stack.trace[i]);
  67
  68     return size;
  69   }
  70
  71   return 0;
  72 }
  73
  74 }  // namespace
  75
  76 SANITIZER_INTERFACE_ATTRIBUTE
  77 const char *__asan_locate_address(uptr addr, char *name, uptr name_size,
  78                                   uptr *region_address_ptr,
  79                                   uptr *region_size_ptr) {
  80   AddressDescription descr(addr);
  81   uptr region_address = 0;
  82   uptr region_size = 0;
  83   const char *region_kind = nullptr;
  84   if (name && name_size > 0) name[0] = 0;
  85
  86   if (auto shadow = descr.AsShadow()) {
  87     // region_{address,size} are already 0
  88     switch (shadow->kind) {
  89       case kShadowKindLow:
  90         region_kind = "low shadow";
  91         break;
  92       case kShadowKindGap:
  93         region_kind = "shadow gap";
  94         break;
  95       case kShadowKindHigh:
  96         region_kind = "high shadow";
  97         break;
  98     }
  99   } else if (auto heap = descr.AsHeap()) {
 100     region_kind = "heap";
 101     region_address = heap->chunk_access.chunk_begin;
 102     region_size = heap->chunk_access.chunk_size;
 103   } else if (auto stack = descr.AsStack()) {
 104     region_kind = "stack";
 105     if (!stack->frame_descr) {
 106       // region_{address,size} are already 0
 107     } else {
 108       FindInfoForStackVar(addr, stack->frame_descr, stack->offset, name,
 109                           name_size, region_address, region_size);
 110     }
 111   } else if (auto global = descr.AsGlobal()) {
 112     region_kind = "global";
 113     auto &g = global->globals[0];
 114     internal_strlcpy(name, g.name, name_size);
 115     region_address = g.beg;
 116     region_size = g.size;
 117   } else {
 118     // region_{address,size} are already 0
 119     region_kind = "heap-invalid";
 120   }
 121
 122   CHECK(region_kind);
 123   if (region_address_ptr) *region_address_ptr = region_address;
 124   if (region_size_ptr) *region_size_ptr = region_size;
 125   return region_kind;
 126 }
 127
 128 SANITIZER_INTERFACE_ATTRIBUTE
 129 uptr __asan_get_alloc_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) {
 130   return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ true);
 131 }
 132
 133 SANITIZER_INTERFACE_ATTRIBUTE
 134 uptr __asan_get_free_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) {
 135   return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ false);
 136 }
 137
 138 SANITIZER_INTERFACE_ATTRIBUTE
 139 void __asan_get_shadow_mapping(uptr *shadow_scale, uptr *shadow_offset) {
 140   if (shadow_scale)
 141     *shadow_scale = SHADOW_SCALE;
 142   if (shadow_offset)
 143     *shadow_offset = SHADOW_OFFSET;
 144 }