include/android_stub/cutils/native_handle.h

   1 /*
   2  * Copyright (C) 2009 The Android Open Source Project
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef NATIVE_HANDLE_H_
  18 #define NATIVE_HANDLE_H_
  19
  20 #include <stdalign.h>
  21
  22 #ifdef __cplusplus
  23 extern "C" {
  24 #endif
  25
  26 #define NATIVE_HANDLE_MAX_FDS 1024
  27 #define NATIVE_HANDLE_MAX_INTS 1024
  28
  29 /* Declare a char array for use with native_handle_init */
  30 #define NATIVE_HANDLE_DECLARE_STORAGE(name, maxFds, maxInts) \
  31     alignas(native_handle_t) char (name)[                            \
  32       sizeof(native_handle_t) + sizeof(int) * ((maxFds) + (maxInts))]
  33
  34 typedef struct native_handle
  35 {
  36     int version;        /* sizeof(native_handle_t) */
  37     int numFds;         /* number of file-descriptors at &data[0] */
  38     int numInts;        /* number of ints at &data[numFds] */
  39 #if defined(__clang__)
  40 #pragma clang diagnostic push
  41 #pragma clang diagnostic ignored "-Wzero-length-array"
  42 #endif
  43     int data[0];        /* numFds + numInts ints */
  44 #if defined(__clang__)
  45 #pragma clang diagnostic pop
  46 #endif
  47 } native_handle_t;
  48
  49 typedef const native_handle_t* buffer_handle_t;
  50
  51 /*
  52  * native_handle_close
  53  *
  54  * closes the file descriptors contained in this native_handle_t
  55  *
  56  * return 0 on success, or a negative error code on failure
  57  *
  58  */
  59 int native_handle_close(const native_handle_t* h);
  60
  61 /*
  62  * native_handle_init
  63  *
  64  * Initializes a native_handle_t from storage.  storage must be declared with
  65  * NATIVE_HANDLE_DECLARE_STORAGE.  numFds and numInts must not respectively
  66  * exceed maxFds and maxInts used to declare the storage.
  67  */
  68 native_handle_t* native_handle_init(char* storage, int numFds, int numInts);
  69
  70 /*
  71  * native_handle_create
  72  *
  73  * creates a native_handle_t and initializes it. must be destroyed with
  74  * native_handle_delete(). Note that numFds must be <= NATIVE_HANDLE_MAX_FDS,
  75  * numInts must be <= NATIVE_HANDLE_MAX_INTS, and both must be >= 0.
  76  *
  77  */
  78 native_handle_t* native_handle_create(int numFds, int numInts);
  79
  80 /*
  81  * native_handle_clone
  82  *
  83  * creates a native_handle_t and initializes it from another native_handle_t.
  84  * Must be destroyed with native_handle_delete().
  85  *
  86  */
  87 native_handle_t* native_handle_clone(const native_handle_t* handle);
  88
  89 /*
  90  * native_handle_delete
  91  *
  92  * frees a native_handle_t allocated with native_handle_create().
  93  * This ONLY frees the memory allocated for the native_handle_t, but doesn't
  94  * close the file descriptors; which can be achieved with native_handle_close().
  95  *
  96  * return 0 on success, or a negative error code on failure
  97  *
  98  */
  99 int native_handle_delete(native_handle_t* h);
 100
 101
 102 #ifdef __cplusplus
 103 }
 104 #endif
 105
 106 #endif /* NATIVE_HANDLE_H_ */