lib/asan/asan_debugging.cc

//===-- asan_debugging.cc -------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// This file contains various functions that are generally useful to call when
// using a debugger (LLDB, GDB).
//===----------------------------------------------------------------------===//

#include "asan_allocator.h"
#include "asan_flags.h"
#include "asan_internal.h"
#include "asan_mapping.h"
#include "asan_report.h"
#include "asan_thread.h"

namespace __asan {

void GetInfoForStackVar(uptr addr, AddressDescription *descr, AsanThread *t) {
  descr->name[0] = 0;
  descr->region_address = 0;
  descr->region_size = 0;
  descr->region_kind = "stack";

  AsanThread::StackFrameAccess access;
  if (!t->GetStackFrameAccessByAddr(addr, &access))
    return;
  InternalMmapVector<StackVarDescr> vars(16);
  if (!ParseFrameDescription(access.frame_descr, &vars)) {
    return;
  }

  for (uptr i = 0; i < vars.size(); i++) {
    if (access.offset <= vars[i].beg + vars[i].size) {
      internal_strncat(descr->name, vars[i].name_pos,
                       Min(descr->name_size, vars[i].name_len));
      descr->region_address = addr - (access.offset - vars[i].beg);
      descr->region_size = vars[i].size;
      return;
    }
  }
}

void GetInfoForHeapAddress(uptr addr, AddressDescription *descr) {
  AsanChunkView chunk = FindHeapChunkByAddress(addr);

  descr->name[0] = 0;
  descr->region_address = 0;
  descr->region_size = 0;

  if (!chunk.IsValid()) {
    descr->region_kind = "heap-invalid";
    return;
  }

  descr->region_address = chunk.Beg();
  descr->region_size = chunk.UsedSize();
  descr->region_kind = "heap";
}

void AsanLocateAddress(uptr addr, AddressDescription *descr) {
  if (DescribeAddressIfShadow(addr, descr, /* print */ false)) {
    return;
  }
  if (GetInfoForAddressIfGlobal(addr, descr)) {
    return;
  }
  asanThreadRegistry().Lock();
  AsanThread *thread = FindThreadByStackAddress(addr);
  asanThreadRegistry().Unlock();
  if (thread) {
    GetInfoForStackVar(addr, descr, thread);
    return;
  }
  GetInfoForHeapAddress(addr, descr);
}

static uptr AsanGetStack(uptr addr, uptr *trace, u32 size, u32 *thread_id,
                         bool alloc_stack) {
  AsanChunkView chunk = FindHeapChunkByAddress(addr);
  if (!chunk.IsValid()) return 0;

  StackTrace stack(nullptr, 0);
  if (alloc_stack) {
    if (chunk.AllocTid() == kInvalidTid) return 0;
    stack = chunk.GetAllocStack();
    if (thread_id) *thread_id = chunk.AllocTid();
  } else {
    if (chunk.FreeTid() == kInvalidTid) return 0;
    stack = chunk.GetFreeStack();
    if (thread_id) *thread_id = chunk.FreeTid();
  }

  if (trace && size) {
    size = Min(size, Min(stack.size, kStackTraceMax));
    for (uptr i = 0; i < size; i++)
      trace[i] = StackTrace::GetPreviousInstructionPc(stack.trace[i]);

    return size;
  }

  return 0;
}

} // namespace __asan

using namespace __asan;

SANITIZER_INTERFACE_ATTRIBUTE
const char *__asan_locate_address(uptr addr, char *name, uptr name_size,
                                  uptr *region_address, uptr *region_size) {
  AddressDescription descr = { name, name_size, 0, 0, nullptr };
  AsanLocateAddress(addr, &descr);
  if (region_address) *region_address = descr.region_address;
  if (region_size) *region_size = descr.region_size;
  return descr.region_kind;
}

SANITIZER_INTERFACE_ATTRIBUTE
uptr __asan_get_alloc_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) {
  return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ true);
}

SANITIZER_INTERFACE_ATTRIBUTE
uptr __asan_get_free_stack(uptr addr, uptr *trace, uptr size, u32 *thread_id) {
  return AsanGetStack(addr, trace, size, thread_id, /* alloc_stack */ false);
}

SANITIZER_INTERFACE_ATTRIBUTE
void __asan_get_shadow_mapping(uptr *shadow_scale, uptr *shadow_offset) {
  if (shadow_scale)
    *shadow_scale = SHADOW_SCALE;
  if (shadow_offset)
    *shadow_offset = SHADOW_OFFSET;
}