1 /*
2 * Copyright 2016, 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 #include "debuggerd/util.h"
18
19 #include <sys/socket.h>
20
21 #include <utility>
22
23 #include <android-base/unique_fd.h>
24 #include <cutils/sockets.h>
25 #include <debuggerd/protocol.h>
26
27 #include "private/libc_logging.h"
28
29 using android::base::unique_fd;
30
send_fd(int sockfd,const void * data,size_t len,unique_fd fd)31 ssize_t send_fd(int sockfd, const void* data, size_t len, unique_fd fd) {
32 char cmsg_buf[CMSG_SPACE(sizeof(int))];
33
34 iovec iov = { .iov_base = const_cast<void*>(data), .iov_len = len };
35 msghdr msg = {
36 .msg_iov = &iov, .msg_iovlen = 1, .msg_control = cmsg_buf, .msg_controllen = sizeof(cmsg_buf),
37 };
38 auto cmsg = CMSG_FIRSTHDR(&msg);
39 cmsg->cmsg_level = SOL_SOCKET;
40 cmsg->cmsg_type = SCM_RIGHTS;
41 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
42 *reinterpret_cast<int*>(CMSG_DATA(cmsg)) = fd.get();
43
44 return TEMP_FAILURE_RETRY(sendmsg(sockfd, &msg, 0));
45 }
46
recv_fd(int sockfd,void * _Nonnull data,size_t len,unique_fd * _Nullable out_fd)47 ssize_t recv_fd(int sockfd, void* _Nonnull data, size_t len, unique_fd* _Nullable out_fd) {
48 char cmsg_buf[CMSG_SPACE(sizeof(int))];
49
50 iovec iov = { .iov_base = const_cast<void*>(data), .iov_len = len };
51 msghdr msg = {
52 .msg_iov = &iov,
53 .msg_iovlen = 1,
54 .msg_control = cmsg_buf,
55 .msg_controllen = sizeof(cmsg_buf),
56 .msg_flags = 0,
57 };
58 auto cmsg = CMSG_FIRSTHDR(&msg);
59 cmsg->cmsg_level = SOL_SOCKET;
60 cmsg->cmsg_type = SCM_RIGHTS;
61 cmsg->cmsg_len = CMSG_LEN(sizeof(int));
62
63 ssize_t result = TEMP_FAILURE_RETRY(recvmsg(sockfd, &msg, 0));
64 if (result == -1) {
65 return -1;
66 }
67
68 unique_fd fd;
69 bool received_fd = msg.msg_controllen == sizeof(cmsg_buf);
70 if (received_fd) {
71 fd.reset(*reinterpret_cast<int*>(CMSG_DATA(cmsg)));
72 }
73
74 if ((msg.msg_flags & MSG_TRUNC) != 0) {
75 errno = EFBIG;
76 return -1;
77 } else if ((msg.msg_flags & MSG_CTRUNC) != 0) {
78 errno = ERANGE;
79 return -1;
80 }
81
82 if (out_fd) {
83 *out_fd = std::move(fd);
84 } else if (received_fd) {
85 errno = ERANGE;
86 return -1;
87 }
88
89 return result;
90 }
91
Pipe(unique_fd * read,unique_fd * write)92 bool Pipe(unique_fd* read, unique_fd* write) {
93 int pipefds[2];
94 if (pipe(pipefds) != 0) {
95 return false;
96 }
97 read->reset(pipefds[0]);
98 write->reset(pipefds[1]);
99 return true;
100 }
101