cutils/sockets.h

   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 <stdlib.h>
  22 #include <string.h>
  23 #include <stdbool.h>
  24
  25 #ifdef HAVE_WINSOCK
  26 #include <winsock2.h>
  27 typedef int  socklen_t;
  28 #elif HAVE_SYS_SOCKET_H
  29 #include <sys/socket.h>
  30 #endif
  31
  32 #define ANDROID_SOCKET_ENV_PREFIX       "ANDROID_SOCKET_"
  33 #define ANDROID_SOCKET_DIR              "/dev/socket"
  34
  35 #ifdef __cplusplus
  36 extern "C" {
  37 #endif
  38
  39 /*
  40  * android_get_control_socket - simple helper function to get the file
  41  * descriptor of our init-managed Unix domain socket. `name' is the name of the
  42  * socket, as given in init.rc. Returns -1 on error.
  43  *
  44  * This is inline and not in libcutils proper because we want to use this in
  45  * third-party daemons with minimal modification.
  46  */
  47 static inline int android_get_control_socket(const char *name)
  48 {
  49         char key[64] = ANDROID_SOCKET_ENV_PREFIX;
  50         const char *val;
  51         int fd;
  52
  53         /* build our environment variable, counting cycles like a wolf ... */
  54 #if HAVE_STRLCPY
  55         strlcpy(key + sizeof(ANDROID_SOCKET_ENV_PREFIX) - 1,
  56                 name,
  57                 sizeof(key) - sizeof(ANDROID_SOCKET_ENV_PREFIX));
  58 #else   /* for the host, which may lack the almightly strncpy ... */
  59         strncpy(key + sizeof(ANDROID_SOCKET_ENV_PREFIX) - 1,
  60                 name,
  61                 sizeof(key) - sizeof(ANDROID_SOCKET_ENV_PREFIX));
  62         key[sizeof(key)-1] = '\0';
  63 #endif
  64
  65         val = getenv(key);
  66         if (!val)
  67                 return -1;
  68
  69         errno = 0;
  70         fd = strtol(val, NULL, 10);
  71         if (errno)
  72                 return -1;
  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 extern int socket_loopback_client(int port, int type);
  88 extern int socket_network_client(const char *host, int port, int type);
  89 extern int socket_loopback_server(int port, int type);
  90 extern int socket_local_server(const char *name, int namespaceId, int type);
  91 extern int socket_local_server_bind(int s, const char *name, int namespaceId);
  92 extern int socket_local_client_connect(int fd,
  93         const char *name, int namespaceId, int type);
  94 extern int socket_local_client(const char *name, int namespaceId, int type);
  95 extern int socket_inaddr_any_server(int port, int type);
  96
  97 /*
  98  * socket_peer_is_trusted - Takes a socket which is presumed to be a
  99  * connected local socket (e.g. AF_LOCAL) and returns whether the peer
 100  * (the userid that owns the process on the other end of that socket)
 101  * is one of the two trusted userids, root or shell.
 102  *
 103  * Note: This only works as advertised on the Android OS and always
 104  * just returns true when called on other operating systems.
 105  */
 106 extern bool socket_peer_is_trusted(int fd);
 107
 108 #ifdef __cplusplus
 109 }
 110 #endif
 111
 112 #endif /* __CUTILS_SOCKETS_H */