xref: /aosp_15_r20/frameworks/native/libs/binder/FdUtils.h (revision 38e8c45f13ce32b0dcecb25141ffecaf386fa17f)
1 /*
2  * Copyright (C) 2023 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 #pragma once
18 
19 #include <binder/unique_fd.h>
20 
21 #if defined(_WIN32) || defined(__TRUSTY__)
22 // Pipe and Socketpair are missing there
23 #elif !defined(BINDER_NO_LIBBASE)
24 
25 namespace android::binder {
26 using android::base::Pipe;
27 using android::base::Socketpair;
28 } // namespace android::binder
29 
30 #else // BINDER_NO_LIBBASE
31 
32 #include <sys/socket.h>
33 
34 namespace android::binder {
35 
36 // Inline functions, so that they can be used header-only.
37 
38 // See pipe(2).
39 // This helper hides the details of converting to unique_fd, and also hides the
40 // fact that macOS doesn't support O_CLOEXEC or O_NONBLOCK directly.
41 inline bool Pipe(unique_fd* read, unique_fd* write, int flags = O_CLOEXEC) {
42     int pipefd[2];
43 
44 #if defined(__APPLE__)
45     if (flags & ~(O_CLOEXEC | O_NONBLOCK)) {
46         return false;
47     }
48     if (pipe(pipefd) != 0) {
49         return false;
50     }
51 
52     if (flags & O_CLOEXEC) {
53         if (fcntl(pipefd[0], F_SETFD, FD_CLOEXEC) != 0 ||
54             fcntl(pipefd[1], F_SETFD, FD_CLOEXEC) != 0) {
55             close(pipefd[0]);
56             close(pipefd[1]);
57             return false;
58         }
59     }
60     if (flags & O_NONBLOCK) {
61         if (fcntl(pipefd[0], F_SETFL, O_NONBLOCK) != 0 ||
62             fcntl(pipefd[1], F_SETFL, O_NONBLOCK) != 0) {
63             close(pipefd[0]);
64             close(pipefd[1]);
65             return false;
66         }
67     }
68 #else
69     if (pipe2(pipefd, flags) != 0) {
70         return false;
71     }
72 #endif
73 
74     read->reset(pipefd[0]);
75     write->reset(pipefd[1]);
76     return true;
77 }
78 
79 // See socketpair(2).
80 // This helper hides the details of converting to unique_fd.
Socketpair(int domain,int type,int protocol,unique_fd * left,unique_fd * right)81 inline bool Socketpair(int domain, int type, int protocol, unique_fd* left, unique_fd* right) {
82     int sockfd[2];
83     if (socketpair(domain, type, protocol, sockfd) != 0) {
84         return false;
85     }
86     left->reset(sockfd[0]);
87     right->reset(sockfd[1]);
88     return true;
89 }
90 
91 // See socketpair(2).
92 // This helper hides the details of converting to unique_fd.
Socketpair(int type,unique_fd * left,unique_fd * right)93 inline bool Socketpair(int type, unique_fd* left, unique_fd* right) {
94     return Socketpair(AF_UNIX, type, 0, left, right);
95 }
96 
97 } // namespace android::binder
98 
99 #endif // BINDER_NO_LIBBASE
100