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 /* 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 31 typedef 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 typedef const native_handle_t* buffer_handle_t; 47 48 /* 49 * native_handle_close 50 * 51 * closes the file descriptors contained in this native_handle_t 52 * 53 * return 0 on success, or a negative error code on failure 54 * 55 */ 56 int native_handle_close(const native_handle_t* h); 57 58 /* 59 * native_handle_init 60 * 61 * Initializes a native_handle_t from storage. storage must be declared with 62 * NATIVE_HANDLE_DECLARE_STORAGE. numFds and numInts must not respectively 63 * exceed maxFds and maxInts used to declare the storage. 64 */ 65 native_handle_t* native_handle_init(char* storage, int numFds, int numInts); 66 67 /* 68 * native_handle_create 69 * 70 * creates a native_handle_t and initializes it. must be destroyed with 71 * native_handle_delete(). 72 * 73 */ 74 native_handle_t* native_handle_create(int numFds, int numInts); 75 76 /* 77 * native_handle_clone 78 * 79 * creates a native_handle_t and initializes it from another native_handle_t. 80 * Must be destroyed with native_handle_delete(). 81 * 82 */ 83 native_handle_t* native_handle_clone(const native_handle_t* handle); 84 85 /* 86 * native_handle_delete 87 * 88 * frees a native_handle_t allocated with native_handle_create(). 89 * This ONLY frees the memory allocated for the native_handle_t, but doesn't 90 * close the file descriptors; which can be achieved with native_handle_close(). 91 * 92 * return 0 on success, or a negative error code on failure 93 * 94 */ 95 int native_handle_delete(native_handle_t* h); 96 97 98 #ifdef __cplusplus 99 } 100 #endif 101 102 #endif /* NATIVE_HANDLE_H_ */ 103