libc/bionic/dlmalloc.c

/*
 * Copyright (C) 2012 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.
 */

#include "dlmalloc.h"

#include <fcntl.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>

#include <linux/ashmem.h>

#include <private/libc_logging.h>

// Send dlmalloc errors to the log.
static void __bionic_heap_corruption_error(const char* function);
static void __bionic_heap_usage_error(const char* function, void* address);
#define PROCEED_ON_ERROR 0
#define CORRUPTION_ERROR_ACTION(m) __bionic_heap_corruption_error(__FUNCTION__)
#define USAGE_ERROR_ACTION(m,p) __bionic_heap_usage_error(__FUNCTION__, p)

// We use ashmem to name the anonymous private regions created by dlmalloc.
static void* __bionic_named_anonymous_mmap(size_t length);
#define MMAP(s) __bionic_named_anonymous_mmap(s)

// Ugly inclusion of C file so that bionic specific #defines configure dlmalloc.
#include "../upstream-dlmalloc/malloc.c"

static void __bionic_heap_corruption_error(const char* function) {
  __libc_format_log(ANDROID_LOG_FATAL, "libc", "@@@ ABORTING: heap corruption detected by %s",
                    function);
  abort();
}

static void __bionic_heap_usage_error(const char* function, void* address) {
  __libc_format_log(ANDROID_LOG_FATAL, "libc", "@@@ ABORTING: invalid address %p passed to %s",
                    address, function);
  // So that we can get a memory dump around the specific address.
  *((int**) 0xdeadbaad) = (int*) address;
}

static int __ashmem_create_region(const char* name, size_t size) {
  int fd = open("/dev/ashmem", O_RDWR);
  if (fd == -1) {
    return fd;
  }
  int rc = ioctl(fd, ASHMEM_SET_NAME, name);
  if (rc < 0) {
    close(fd);
    return rc;
  }
  rc = ioctl(fd, ASHMEM_SET_SIZE, size);
  if (rc < 0) {
    close(fd);
    return rc;
  }
  return fd;
}

static void* __bionic_named_anonymous_mmap(size_t length) {
  int fd = __ashmem_create_region("libc malloc", length);
  if (fd < 0) {
    return MAP_FAILED;
  }
  void* result = mmap(NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
  close (fd);
  return result;
}