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_ */ 107