1 /*
2 * Copyright (C) 2006 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 __CUTILS_SOCKETS_H
18 #define __CUTILS_SOCKETS_H
19
20 #include <errno.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <stdbool.h>
25
26 #if defined(_WIN32)
27
28 #include <winsock2.h>
29 #include <ws2tcpip.h>
30
31 typedef int socklen_t;
32 typedef SOCKET cutils_socket_t;
33
34 #else
35
36 #include <sys/socket.h>
37
38 typedef int cutils_socket_t;
39 #define INVALID_SOCKET (-1)
40
41 #endif
42
43 #define ANDROID_SOCKET_ENV_PREFIX "ANDROID_SOCKET_"
44 #define ANDROID_SOCKET_DIR "/dev/socket"
45
46 #ifdef __cplusplus
47 extern "C" {
48 #endif
49
50 /*
51 * android_get_control_socket - simple helper function to get the file
52 * descriptor of our init-managed Unix domain socket. `name' is the name of the
53 * socket, as given in init.rc. Returns -1 on error.
54 *
55 * This is inline and not in libcutils proper because we want to use this in
56 * third-party daemons with minimal modification.
57 */
android_get_control_socket(const char * name)58 static inline int android_get_control_socket(const char* name)
59 {
60 char key[64];
61 snprintf(key, sizeof(key), ANDROID_SOCKET_ENV_PREFIX "%s", name);
62
63 const char* val = getenv(key);
64 if (!val) {
65 return -1;
66 }
67
68 errno = 0;
69 int fd = strtol(val, NULL, 10);
70 if (errno) {
71 return -1;
72 }
73
74 return fd;
75 }
76
77 /*
78 * See also android.os.LocalSocketAddress.Namespace
79 */
80 // Linux "abstract" (non-filesystem) namespace
81 #define ANDROID_SOCKET_NAMESPACE_ABSTRACT 0
82 // Android "reserved" (/dev/socket) namespace
83 #define ANDROID_SOCKET_NAMESPACE_RESERVED 1
84 // Normal filesystem namespace
85 #define ANDROID_SOCKET_NAMESPACE_FILESYSTEM 2
86
87 /*
88 * Functions to create sockets for some common usages.
89 *
90 * All these functions are implemented for Unix, but only a few are implemented
91 * for Windows. Those which are can be identified by the cutils_socket_t
92 * return type. The idea is to be able to use this return value with the
93 * standard Unix socket functions on any platform.
94 *
95 * On Unix the returned cutils_socket_t is a standard int file descriptor and
96 * can always be used as normal with all file descriptor functions.
97 *
98 * On Windows utils_socket_t is an unsigned int pointer, and is only valid
99 * with functions that specifically take a socket, e.g. send(), sendto(),
100 * recv(), and recvfrom(). General file descriptor functions such as read(),
101 * write(), and close() will not work with utils_socket_t and will require
102 * special handling.
103 *
104 * These functions return INVALID_SOCKET (-1) on failure for all platforms.
105 */
106 int socket_loopback_client(int port, int type);
107 cutils_socket_t socket_network_client(const char* host, int port, int type);
108 int socket_network_client_timeout(const char* host, int port, int type,
109 int timeout, int* getaddrinfo_error);
110 int socket_loopback_server(int port, int type);
111 int socket_local_server(const char* name, int namespaceId, int type);
112 int socket_local_server_bind(int s, const char* name, int namespaceId);
113 int socket_local_client_connect(int fd, const char *name, int namespaceId,
114 int type);
115 int socket_local_client(const char* name, int namespaceId, int type);
116 cutils_socket_t socket_inaddr_any_server(int port, int type);
117
118 /*
119 * Closes a cutils_socket_t. Windows doesn't allow calling close() on a socket
120 * so this is a cross-platform way to close a cutils_socket_t.
121 *
122 * Returns 0 on success.
123 */
124 int socket_close(cutils_socket_t sock);
125
126 /*
127 * Sets socket receive timeout using SO_RCVTIMEO. Setting |timeout_ms| to 0
128 * disables receive timeouts.
129 *
130 * Return 0 on success.
131 */
132 int socket_set_receive_timeout(cutils_socket_t sock, int timeout_ms);
133
134 /*
135 * Returns the local port the socket is bound to or -1 on error.
136 */
137 int socket_get_local_port(cutils_socket_t sock);
138
139 /*
140 * Sends to a socket from multiple buffers; wraps writev() on Unix or WSASend()
141 * on Windows. This can give significant speedup compared to calling send()
142 * multiple times.
143 *
144 * Example usage:
145 * cutils_socket_buffer_t buffers[2] = { {data0, len0}, {data1, len1} };
146 * socket_send_buffers(sock, buffers, 2);
147 *
148 * If you try to pass more than SOCKET_SEND_BUFFERS_MAX_BUFFERS buffers into
149 * this function it will return -1 without sending anything.
150 *
151 * Returns the number of bytes written or -1 on error.
152 */
153 typedef struct {
154 const void* data;
155 size_t length;
156 } cutils_socket_buffer_t;
157
158 #define SOCKET_SEND_BUFFERS_MAX_BUFFERS 16
159
160 ssize_t socket_send_buffers(cutils_socket_t sock,
161 const cutils_socket_buffer_t* buffers,
162 size_t num_buffers);
163
164 /*
165 * socket_peer_is_trusted - Takes a socket which is presumed to be a
166 * connected local socket (e.g. AF_LOCAL) and returns whether the peer
167 * (the userid that owns the process on the other end of that socket)
168 * is one of the two trusted userids, root or shell.
169 *
170 * Note: This only works as advertised on the Android OS and always
171 * just returns true when called on other operating systems.
172 */
173 extern bool socket_peer_is_trusted(int fd);
174
175 #ifdef __cplusplus
176 }
177 #endif
178
179 #endif /* __CUTILS_SOCKETS_H */
180