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#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
34typedef 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
49typedef 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 */
59int 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 */
68native_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 */
78native_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 */
87native_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 */
99int native_handle_delete(native_handle_t* h);
100
101
102#ifdef __cplusplus
103}
104#endif
105
106#endif /* NATIVE_HANDLE_H_ */
107