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