Quelle  bionic_fdtrack.h

/*
 * Copyright (C) 2019 The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#pragma once

#include <sys/cdefs.h>

#include <stdatomic.h>

#include "platform/bionic/fdtrack.h"

#include "bionic/pthread_internal.h"
#include "private/ErrnoRestorer.h"
#include "private/bionic_tls.h"

extern "C" _Atomic(android_fdtrack_hook_t) __android_fdtrack_hook;
extern "C" bool __android_fdtrack_globally_disabled;

// Macro to record file descriptor creation.
// e.g.:
//   int socket(int domain, int type, int protocol) {
//     return FDTRACK_CREATE_NAME("socket", __socket(domain, type, protocol));
//   }
#define FDTRACK_CREATE_NAME(name, fd_value)                        \
  ({                                                               \
    int __fd = (fd_value);                                         \
    if (__fd != -1 && __predict_false(__android_fdtrack_hook) &&   \
        !__predict_false(__get_thread()->is_vforked())) {          \
      bionic_tls& tls = __get_bionic_tls();                        \
      /* fdtrack_disabled is only true during reentrant calls. */  \
      if (!__predict_false(tls.fdtrack_disabled) &&                \
          !__predict_false(__android_fdtrack_globally_disabled)) { \
        ErrnoRestorer r;                                           \
        tls.fdtrack_disabled = true;                               \
        android_fdtrack_event event;                               \
        event.fd = __fd;                                           \
        event.type = ANDROID_FDTRACK_EVENT_TYPE_CREATE;            \
        event.data.create.function_name = name;                    \
        atomic_load (&__android_fdtrack_hook)(&event);             \
        tls.fdtrack_disabled = false;                              \
      }                                                            \
    }                                                              \
    __fd;                                                          \
  })

// Macro to record file descriptor creation, with the current function's name.
// e.g.:
//   int socket(int domain, int type, int protocol) {
//     return FDTRACK_CREATE_NAME(__socket(domain, type, protocol));
//   }
#define FDTRACK_CREATE(fd_value) FDTRACK_CREATE_NAME(__func__, (fd_value))

// Macro to record file descriptor closure.
// Note that this does not actually close the file descriptor.
#define FDTRACK_CLOSE(fd_value)                                    \
  ({                                                               \
    int __fd = (fd_value);                                         \
    if (__fd != -1 && __predict_false(__android_fdtrack_hook) &&   \
        !__predict_false(__get_thread()->is_vforked())) {          \
      bionic_tls& tls = __get_bionic_tls();                        \
      if (!__predict_false(tls.fdtrack_disabled) &&                \
          !__predict_false(__android_fdtrack_globally_disabled)) { \
        int saved_errno = errno;                                   \
        tls.fdtrack_disabled = true;                               \
        android_fdtrack_event event;                               \
        event.fd = __fd;                                           \
        event.type = ANDROID_FDTRACK_EVENT_TYPE_CLOSE;             \
        atomic_load (&__android_fdtrack_hook)(&event);             \
        tls.fdtrack_disabled = false;                              \
        errno = saved_errno;                                       \
      }                                                            \
    }                                                              \
    __fd;                                                          \
  })