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
23extern "C" {
24#endif
25
26/* Declare a char array for use with native_handle_init */
27#define NATIVE_HANDLE_DECLARE_STORAGE(name, maxFds, maxInts) \
28    alignas(native_handle_t) char name[                            \
29      sizeof(native_handle_t) + sizeof(int) * (maxFds + maxInts)]
30
31typedef struct native_handle
32{
33    int version;        /* sizeof(native_handle_t) */
34    int numFds;         /* number of file-descriptors at &data[0] */
35    int numInts;        /* number of ints at &data[numFds] */
36#if defined(__clang__)
37#pragma clang diagnostic push
38#pragma clang diagnostic ignored "-Wzero-length-array"
39#endif
40    int data[0];        /* numFds + numInts ints */
41#if defined(__clang__)
42#pragma clang diagnostic pop
43#endif
44} native_handle_t;
45
46/*
47 * native_handle_close
48 *
49 * closes the file descriptors contained in this native_handle_t
50 *
51 * return 0 on success, or a negative error code on failure
52 *
53 */
54int native_handle_close(const native_handle_t* h);
55
56/*
57 * native_handle_init
58 *
59 * Initializes a native_handle_t from storage.  storage must be declared with
60 * NATIVE_HANDLE_DECLARE_STORAGE.  numFds and numInts must not respectively
61 * exceed maxFds and maxInts used to declare the storage.
62 */
63native_handle_t* native_handle_init(char* storage, int numFds, int numInts);
64
65/*
66 * native_handle_create
67 *
68 * creates a native_handle_t and initializes it. must be destroyed with
69 * native_handle_delete().
70 *
71 */
72native_handle_t* native_handle_create(int numFds, int numInts);
73
74/*
75 * native_handle_clone
76 *
77 * creates a native_handle_t and initializes it from another native_handle_t.
78 * Must be destroyed with native_handle_delete().
79 *
80 */
81native_handle_t* native_handle_clone(const native_handle_t* handle);
82
83/*
84 * native_handle_delete
85 *
86 * frees a native_handle_t allocated with native_handle_create().
87 * This ONLY frees the memory allocated for the native_handle_t, but doesn't
88 * close the file descriptors; which can be achieved with native_handle_close().
89 *
90 * return 0 on success, or a negative error code on failure
91 *
92 */
93int native_handle_delete(native_handle_t* h);
94
95
96#ifdef __cplusplus
97}
98#endif
99
100#endif /* NATIVE_HANDLE_H_ */
101