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      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 #include <cutils/sockets.h>
     18 
     19 #include <errno.h>
     20 #include <stddef.h>
     21 #include <stdlib.h>
     22 #include <string.h>
     23 #include <unistd.h>
     24 
     25 #if defined(_WIN32)
     26 
     27 int socket_local_client(const char *name, int namespaceId, int type)
     28 {
     29     errno = ENOSYS;
     30     return -1;
     31 }
     32 
     33 #else /* !_WIN32 */
     34 
     35 #include <sys/socket.h>
     36 #include <sys/un.h>
     37 #include <sys/select.h>
     38 #include <sys/types.h>
     39 
     40 #include "socket_local_unix.h"
     41 
     42 #define LISTEN_BACKLOG 4
     43 
     44 /* Documented in header file. */
     45 int socket_make_sockaddr_un(const char *name, int namespaceId,
     46         struct sockaddr_un *p_addr, socklen_t *alen)
     47 {
     48     memset (p_addr, 0, sizeof (*p_addr));
     49     size_t namelen;
     50 
     51     switch (namespaceId) {
     52         case ANDROID_SOCKET_NAMESPACE_ABSTRACT:
     53 #if defined(__linux__)
     54             namelen  = strlen(name);
     55 
     56             // Test with length +1 for the *initial* '\0'.
     57             if ((namelen + 1) > sizeof(p_addr->sun_path)) {
     58                 goto error;
     59             }
     60 
     61             /*
     62              * Note: The path in this case is *not* supposed to be
     63              * '\0'-terminated. ("man 7 unix" for the gory details.)
     64              */
     65 
     66             p_addr->sun_path[0] = 0;
     67             memcpy(p_addr->sun_path + 1, name, namelen);
     68 #else
     69             /* this OS doesn't have the Linux abstract namespace */
     70 
     71             namelen = strlen(name) + strlen(FILESYSTEM_SOCKET_PREFIX);
     72             /* unix_path_max appears to be missing on linux */
     73             if (namelen > sizeof(*p_addr)
     74                     - offsetof(struct sockaddr_un, sun_path) - 1) {
     75                 goto error;
     76             }
     77 
     78             strcpy(p_addr->sun_path, FILESYSTEM_SOCKET_PREFIX);
     79             strcat(p_addr->sun_path, name);
     80 #endif
     81         break;
     82 
     83         case ANDROID_SOCKET_NAMESPACE_RESERVED:
     84             namelen = strlen(name) + strlen(ANDROID_RESERVED_SOCKET_PREFIX);
     85             /* unix_path_max appears to be missing on linux */
     86             if (namelen > sizeof(*p_addr)
     87                     - offsetof(struct sockaddr_un, sun_path) - 1) {
     88                 goto error;
     89             }
     90 
     91             strcpy(p_addr->sun_path, ANDROID_RESERVED_SOCKET_PREFIX);
     92             strcat(p_addr->sun_path, name);
     93         break;
     94 
     95         case ANDROID_SOCKET_NAMESPACE_FILESYSTEM:
     96             namelen = strlen(name);
     97             /* unix_path_max appears to be missing on linux */
     98             if (namelen > sizeof(*p_addr)
     99                     - offsetof(struct sockaddr_un, sun_path) - 1) {
    100                 goto error;
    101             }
    102 
    103             strcpy(p_addr->sun_path, name);
    104         break;
    105         default:
    106             // invalid namespace id
    107             return -1;
    108     }
    109 
    110     p_addr->sun_family = AF_LOCAL;
    111     *alen = namelen + offsetof(struct sockaddr_un, sun_path) + 1;
    112     return 0;
    113 error:
    114     return -1;
    115 }
    116 
    117 /**
    118  * connect to peer named "name" on fd
    119  * returns same fd or -1 on error.
    120  * fd is not closed on error. that's your job.
    121  *
    122  * Used by AndroidSocketImpl
    123  */
    124 int socket_local_client_connect(int fd, const char* name, int namespaceId, int /*type*/) {
    125     struct sockaddr_un addr;
    126     socklen_t alen;
    127     int err;
    128 
    129     err = socket_make_sockaddr_un(name, namespaceId, &addr, &alen);
    130 
    131     if (err < 0) {
    132         goto error;
    133     }
    134 
    135     if(connect(fd, (struct sockaddr *) &addr, alen) < 0) {
    136         goto error;
    137     }
    138 
    139     return fd;
    140 
    141 error:
    142     return -1;
    143 }
    144 
    145 /**
    146  * connect to peer named "name"
    147  * returns fd or -1 on error
    148  */
    149 int socket_local_client(const char *name, int namespaceId, int type)
    150 {
    151     int s;
    152 
    153     s = socket(AF_LOCAL, type, 0);
    154     if(s < 0) return -1;
    155 
    156     if ( 0 > socket_local_client_connect(s, name, namespaceId, type)) {
    157         close(s);
    158         return -1;
    159     }
    160 
    161     return s;
    162 }
    163 
    164 #endif /* !_WIN32 */
    165