ceph/src/seastar/include/seastar/net/unix_address.hh

   1 /*
   2  * This file is open source software, licensed to you under the terms
   3  * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
   4  * distributed with this work for additional information regarding copyright
   5  * ownership.  You may not use this file except in compliance with the License.
   6  *
   7  * You may obtain a copy of the License at
   8  *
   9  *   http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing,
  12  * software distributed under the License is distributed on an
  13  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  14  * KIND, either express or implied.  See the License for the
  15  * specific language governing permissions and limitations
  16  * under the License.
  17  */
  18 /*
  19  * Copyright (C) 2019 Red Hat, Inc.
  20  */
  21 #pragma once
  22
  23 #include <iosfwd>
  24 #include <sys/types.h>
  25 #include <sys/un.h>
  26 #include <string>
  27
  28 namespace seastar {
  29
  30 /*!
  31     A helper struct for creating/manipulating UNIX-domain sockets.
  32
  33     A UNIX-domain socket is either named or unnamed. If named, the name is either
  34     a path in the filesystem namespace, or an abstract-domain identifier. Abstract-domain
  35     names start with a null byte, and may contain non-printable characters.
  36
  37     std::string() can hold a sequence of arbitrary bytes, and has a length() attribute
  38     that does not rely on using strlen(). Thus it is used here to hold the address.
  39  */
  40 struct unix_domain_addr {
  41     const std::string name;
  42     const int path_count;  //  either name.length() or name.length()+1. See path_length_aux() below.
  43
  44     explicit unix_domain_addr(const std::string& fn) : name{fn}, path_count{path_length_aux()} {}
  45
  46     explicit unix_domain_addr(const char* fn) : name{fn}, path_count{path_length_aux()} {}
  47
  48     int path_length() const { return path_count; }
  49
  50     //  the following holds:
  51     //  for abstract name: name.length() == number of meaningful bytes, including the null in name[0].
  52     //  for filesystem path: name.length() does not count the implicit terminating null.
  53     //  Here we tweak the outside-visible length of the address.
  54     int path_length_aux() const {
  55         auto pl = (int)name.length();
  56         if (!pl || (name[0] == '\0')) {
  57             // unnamed, or abstract-namespace
  58             return pl;
  59         }
  60         return 1 + pl;
  61     }
  62
  63     const char* path_bytes() const { return name.c_str(); }
  64
  65     bool operator==(const unix_domain_addr& a) const {
  66         return name == a.name;
  67     }
  68     bool operator!=(const unix_domain_addr& a) const {
  69         return !(*this == a);
  70     }
  71 };
  72
  73 std::ostream& operator<<(std::ostream&, const unix_domain_addr&);
  74
  75 } // namespace seastar