lib/asan/asan_thread_registry.cc

//===-- asan_thread_registry.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.
//
// AsanThreadRegistry-related code. AsanThreadRegistry is a container
// for summaries of all created threads.
//===----------------------------------------------------------------------===//

#include "asan_stack.h"
#include "asan_thread.h"
#include "asan_thread_registry.h"
#include "sanitizer_common/sanitizer_common.h"

namespace __asan {

static AsanThreadRegistry asan_thread_registry(LINKER_INITIALIZED);

AsanThreadRegistry &asanThreadRegistry() {
  return asan_thread_registry;
}

AsanThreadRegistry::AsanThreadRegistry(LinkerInitialized x)
    : main_thread_(x),
      main_thread_summary_(x),
      accumulated_stats_(x),
      max_malloced_memory_(x),
      mu_(x) { }

void AsanThreadRegistry::Init() {
  AsanTSDInit(AsanThreadSummary::TSDDtor);
  main_thread_.set_summary(&main_thread_summary_);
  main_thread_summary_.set_thread(&main_thread_);
  RegisterThread(&main_thread_);
  SetCurrent(&main_thread_);
  // At this point only one thread exists.
  inited_ = true;
}

void AsanThreadRegistry::RegisterThread(AsanThread *thread) {
  BlockingMutexLock lock(&mu_);
  u32 tid = n_threads_;
  n_threads_++;
  CHECK(n_threads_ < kMaxNumberOfThreads);

  AsanThreadSummary *summary = thread->summary();
  CHECK(summary != 0);
  summary->set_tid(tid);
  thread_summaries_[tid] = summary;
}

void AsanThreadRegistry::UnregisterThread(AsanThread *thread) {
  BlockingMutexLock lock(&mu_);
  FlushToAccumulatedStatsUnlocked(&thread->stats());
  AsanThreadSummary *summary = thread->summary();
  CHECK(summary);
  summary->set_thread(0);
}

AsanThread *AsanThreadRegistry::GetMain() {
  return &main_thread_;
}

AsanThread *AsanThreadRegistry::GetCurrent() {
  AsanThreadSummary *summary = (AsanThreadSummary *)AsanTSDGet();
  if (!summary) {
#if ASAN_ANDROID
    // On Android, libc constructor is called _after_ asan_init, and cleans up
    // TSD. Try to figure out if this is still the main thread by the stack
    // address. We are not entirely sure that we have correct main thread
    // limits, so only do this magic on Android, and only if the found thread is
    // the main thread.
    AsanThread* thread = FindThreadByStackAddress((uptr)&summary);
    if (thread && thread->tid() == 0) {
      SetCurrent(thread);
      return thread;
    }
#endif
    return 0;
  }
  return summary->thread();
}

void AsanThreadRegistry::SetCurrent(AsanThread *t) {
  CHECK(t->summary());
  if (flags()->verbosity >= 2) {
    Report("SetCurrent: %p for thread %p\n",
           t->summary(), (void*)GetThreadSelf());
  }
  // Make sure we do not reset the current AsanThread.
  CHECK(AsanTSDGet() == 0);
  AsanTSDSet(t->summary());
  CHECK(AsanTSDGet() == t->summary());
}

AsanStats &AsanThreadRegistry::GetCurrentThreadStats() {
  AsanThread *t = GetCurrent();
  return (t) ? t->stats() : main_thread_.stats();
}

void AsanThreadRegistry::GetAccumulatedStats(AsanStats *stats) {
  BlockingMutexLock lock(&mu_);
  UpdateAccumulatedStatsUnlocked();
  internal_memcpy(stats, &accumulated_stats_, sizeof(accumulated_stats_));
}

uptr AsanThreadRegistry::GetCurrentAllocatedBytes() {
  BlockingMutexLock lock(&mu_);
  UpdateAccumulatedStatsUnlocked();
  uptr malloced = accumulated_stats_.malloced;
  uptr freed = accumulated_stats_.freed;
  // Return sane value if malloced < freed due to racy
  // way we update accumulated stats.
  return (malloced > freed) ? malloced - freed : 1;
}

uptr AsanThreadRegistry::GetHeapSize() {
  BlockingMutexLock lock(&mu_);
  UpdateAccumulatedStatsUnlocked();
  return accumulated_stats_.mmaped - accumulated_stats_.munmaped;
}

uptr AsanThreadRegistry::GetFreeBytes() {
  BlockingMutexLock lock(&mu_);
  UpdateAccumulatedStatsUnlocked();
  uptr total_free = accumulated_stats_.mmaped
                  - accumulated_stats_.munmaped
                  + accumulated_stats_.really_freed
                  + accumulated_stats_.really_freed_redzones;
  uptr total_used = accumulated_stats_.malloced
                  + accumulated_stats_.malloced_redzones;
  // Return sane value if total_free < total_used due to racy
  // way we update accumulated stats.
  return (total_free > total_used) ? total_free - total_used : 1;
}

// Return several stats counters with a single call to
// UpdateAccumulatedStatsUnlocked().
void AsanThreadRegistry::FillMallocStatistics(AsanMallocStats *malloc_stats) {
  BlockingMutexLock lock(&mu_);
  UpdateAccumulatedStatsUnlocked();
  malloc_stats->blocks_in_use = accumulated_stats_.mallocs;
  malloc_stats->size_in_use = accumulated_stats_.malloced;
  malloc_stats->max_size_in_use = max_malloced_memory_;
  malloc_stats->size_allocated = accumulated_stats_.mmaped;
}

AsanThreadSummary *AsanThreadRegistry::FindByTid(u32 tid) {
  CHECK(tid < n_threads_);
  CHECK(thread_summaries_[tid]);
  return thread_summaries_[tid];
}

AsanThread *AsanThreadRegistry::FindThreadByStackAddress(uptr addr) {
  BlockingMutexLock lock(&mu_);
  for (u32 tid = 0; tid < n_threads_; tid++) {
    AsanThread *t = thread_summaries_[tid]->thread();
    if (!t || !(t->fake_stack().StackSize())) continue;
    if (t->fake_stack().AddrIsInFakeStack(addr) || t->AddrIsInStack(addr)) {
      return t;
    }
  }
  return 0;
}

void AsanThreadRegistry::UpdateAccumulatedStatsUnlocked() {
  for (u32 tid = 0; tid < n_threads_; tid++) {
    AsanThread *t = thread_summaries_[tid]->thread();
    if (t != 0) {
      FlushToAccumulatedStatsUnlocked(&t->stats());
    }
  }
  // This is not very accurate: we may miss allocation peaks that happen
  // between two updates of accumulated_stats_. For more accurate bookkeeping
  // the maximum should be updated on every malloc(), which is unacceptable.
  if (max_malloced_memory_ < accumulated_stats_.malloced) {
    max_malloced_memory_ = accumulated_stats_.malloced;
  }
}

void AsanThreadRegistry::FlushToAccumulatedStatsUnlocked(AsanStats *stats) {
  // AsanStats consists of variables of type uptr only.
  uptr *dst = (uptr*)&accumulated_stats_;
  uptr *src = (uptr*)stats;
  uptr num_fields = sizeof(AsanStats) / sizeof(uptr);
  for (uptr i = 0; i < num_fields; i++) {
    dst[i] += src[i];
    src[i] = 0;
  }
}

}  // namespace __asan