src/hprof/hprof.cc

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * Preparation and completion of hprof data generation.  The output is
 * written into two files and then combined.  This is necessary because
 * we generate some of the data (strings and classes) while we dump the
 * heap, and some analysis tools require that the class and string data
 * appear first.
 */

#include "hprof.h"
#include "heap.h"
#include "debugger.h"
#include "stringprintf.h"
#include "thread_list.h"
#include "logging.h"

#include <sys/uio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/time.h>
#include <time.h>

namespace art {

namespace hprof {

#define kHeadSuffix "-hptemp"

// TODO: use File::WriteFully
int sysWriteFully(int fd, const void* buf, size_t count, const char* logMsg) {
  while (count != 0) {
    ssize_t actual = TEMP_FAILURE_RETRY(write(fd, buf, count));
    if (actual < 0) {
      int err = errno;
      LOG(ERROR) << StringPrintf("%s: write failed: %s", logMsg, strerror(err));
      return err;
    } else if (actual != (ssize_t) count) {
      LOG(DEBUG) << StringPrintf("%s: partial write (will retry): (%d of %zd)",
          logMsg, (int) actual, count);
      buf = (const void*) (((const uint8_t*) buf) + actual);
    }
    count -= actual;
  }
  return 0;
}

/*
 * Finish up the hprof dump.  Returns true on success.
 */
bool Hprof::Finish() {
  // flush the "tail" portion of the output
  StartNewRecord(HPROF_TAG_HEAP_DUMP_END, HPROF_TIME);
  FlushCurrentRecord();

  // create a new Hprof for the start of the file (as opposed to this, which is the tail)
  Hprof headCtx(file_name_, fd_, true, direct_to_ddms_);
  headCtx.classes_ = classes_;
  headCtx.strings_ = strings_;

  LOG(INFO) << StringPrintf("hprof: dumping heap strings to \"%s\".", file_name_);
  headCtx.DumpStrings();
  headCtx.DumpClasses();

  // write a dummy stack trace record so the analysis tools don't freak out
  headCtx.StartNewRecord(HPROF_TAG_STACK_TRACE, HPROF_TIME);
  headCtx.current_record_.AddU4(HPROF_NULL_STACK_TRACE);
  headCtx.current_record_.AddU4(HPROF_NULL_THREAD);
  headCtx.current_record_.AddU4(0);    // no frames

  headCtx.FlushCurrentRecord();

  // flush to ensure memstream pointer and size are updated
  fflush(headCtx.mem_fp_);
  fflush(mem_fp_);

  if (direct_to_ddms_) {
    // send the data off to DDMS
    struct iovec iov[2];
    iov[0].iov_base = headCtx.file_data_ptr_;
    iov[0].iov_len = headCtx.file_data_size_;
    iov[1].iov_base = file_data_ptr_;
    iov[1].iov_len = file_data_size_;
    Dbg::DdmSendChunkV(CHUNK_TYPE("HPDS"), iov, 2);
  } else {
    // open the output file, and copy the head and tail to it.
    CHECK_EQ(headCtx.fd_, fd_);

    int outFd;
    if (headCtx.fd_ >= 0) {
      outFd = dup(headCtx.fd_);
      if (outFd < 0) {
        LOG(ERROR) << StringPrintf("dup(%d) failed: %s", headCtx.fd_, strerror(errno));
        // continue to fail-handler below
      }
    } else {
      outFd = open(file_name_, O_WRONLY|O_CREAT|O_TRUNC, 0644);
      if (outFd < 0) {
        LOG(ERROR) << StringPrintf("can't open %s: %s", headCtx.file_name_, strerror(errno));
        // continue to fail-handler below
      }
    }
    if (outFd < 0) {
      return false;
    }

    int result = sysWriteFully(outFd, headCtx.file_data_ptr_,
        headCtx.file_data_size_, "hprof-head");
    result |= sysWriteFully(outFd, file_data_ptr_, file_data_size_, "hprof-tail");
    close(outFd);
    if (result != 0) {
      return false;
    }
  }

  // throw out a log message for the benefit of "runhat"
  LOG(INFO) << StringPrintf("hprof: heap dump completed (%dKB)",
      (headCtx.file_data_size_ + file_data_size_ + 1023) / 1024);

  return true;
}

Hprof::~Hprof() {
  // we don't own ctx->fd_, do not close
  if (mem_fp_ != NULL) {
    fclose(mem_fp_);
  }
  free(current_record_.body_);
  free(file_name_);
  free(file_data_ptr_);
}

/*
 * Visitor invoked on every root reference.
 */
void HprofRootVisitor(const Object* obj, void* arg) {
  CHECK(arg != NULL);
  Hprof* hprof = (Hprof*)arg;
  hprof->VisitRoot(obj);
}

void Hprof::VisitRoot(const Object* obj) {
  uint32_t threadId = 0;  // TODO
  /*RootType */ size_t type = 0; // TODO

  static const HprofHeapTag xlate[] = {
    HPROF_ROOT_UNKNOWN,
    HPROF_ROOT_JNI_GLOBAL,
    HPROF_ROOT_JNI_LOCAL,
    HPROF_ROOT_JAVA_FRAME,
    HPROF_ROOT_NATIVE_STACK,
    HPROF_ROOT_STICKY_CLASS,
    HPROF_ROOT_THREAD_BLOCK,
    HPROF_ROOT_MONITOR_USED,
    HPROF_ROOT_THREAD_OBJECT,
    HPROF_ROOT_INTERNED_STRING,
    HPROF_ROOT_FINALIZING,
    HPROF_ROOT_DEBUGGER,
    HPROF_ROOT_REFERENCE_CLEANUP,
    HPROF_ROOT_VM_INTERNAL,
    HPROF_ROOT_JNI_MONITOR,
  };

  CHECK_LT(type, sizeof(xlate) / sizeof(HprofHeapTag));
  if (obj == NULL) {
    return;
  }
  gc_scan_state_ = xlate[type];
  gc_thread_serial_number_ = threadId;
  MarkRootObject(obj, 0);
  gc_scan_state_ = 0;
  gc_thread_serial_number_ = 0;
}

/*
 * Visitor invoked on every heap object.
 */
static void HprofBitmapCallback(Object *obj, void *arg) {
  CHECK(obj != NULL);
  CHECK(arg != NULL);
  Hprof *hprof = (Hprof*)arg;
  hprof->DumpHeapObject(obj);
}

/*
 * Walk the roots and heap writing heap information to the specified
 * file.
 *
 * If "fd" is >= 0, the output will be written to that file descriptor.
 * Otherwise, "file_name_" is used to create an output file.
 *
 * If "direct_to_ddms_" is set, the other arguments are ignored, and data is
 * sent directly to DDMS.
 *
 * Returns 0 on success, or an error code on failure.
 */
int DumpHeap(const char* fileName, int fd, bool directToDdms) {
  CHECK(fileName != NULL);
  ScopedHeapLock lock;
  ScopedThreadStateChange tsc(Thread::Current(), Thread::kRunnable);

  ThreadList* thread_list = Runtime::Current()->GetThreadList();
  thread_list->SuspendAll();

  Hprof hprof(fileName, fd, false, directToDdms);
  Runtime::Current()->VisitRoots(HprofRootVisitor, &hprof);
  Heap::GetLiveBits()->Walk(HprofBitmapCallback, &hprof);
  // TODO: write a HEAP_SUMMARY record
  int success = hprof.Finish() ? 0 : -1;
  thread_list->ResumeAll();
  return success;
}

}  // namespace hprof

}  // namespace art