1 //===-- DomainSocket.cpp --------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "lldb/Host/posix/DomainSocket.h"
10 
11 #include "llvm/Support/Errno.h"
12 #include "llvm/Support/FileSystem.h"
13 
14 #include <cstddef>
15 #include <sys/socket.h>
16 #include <sys/un.h>
17 
18 using namespace lldb;
19 using namespace lldb_private;
20 
21 #ifdef __ANDROID__
22 // Android does not have SUN_LEN
23 #ifndef SUN_LEN
24 #define SUN_LEN(ptr)                                                           \
25   (offsetof(struct sockaddr_un, sun_path) + strlen((ptr)->sun_path))
26 #endif
27 #endif // #ifdef __ANDROID__
28 
29 static const int kDomain = AF_UNIX;
30 static const int kType = SOCK_STREAM;
31 
32 static bool SetSockAddr(llvm::StringRef name, const size_t name_offset,
33                         sockaddr_un *saddr_un, socklen_t &saddr_un_len) {
34   if (name.size() + name_offset > sizeof(saddr_un->sun_path))
35     return false;
36 
37   memset(saddr_un, 0, sizeof(*saddr_un));
38   saddr_un->sun_family = kDomain;
39 
40   memcpy(saddr_un->sun_path + name_offset, name.data(), name.size());
41 
42   // For domain sockets we can use SUN_LEN in order to calculate size of
43   // sockaddr_un, but for abstract sockets we have to calculate size manually
44   // because of leading null symbol.
45   if (name_offset == 0)
46     saddr_un_len = SUN_LEN(saddr_un);
47   else
48     saddr_un_len =
49         offsetof(struct sockaddr_un, sun_path) + name_offset + name.size();
50 
51 #if defined(__APPLE__) || defined(__FreeBSD__) || defined(__NetBSD__) ||       \
52     defined(__OpenBSD__)
53   saddr_un->sun_len = saddr_un_len;
54 #endif
55 
56   return true;
57 }
58 
59 DomainSocket::DomainSocket(bool should_close, bool child_processes_inherit)
60     : Socket(ProtocolUnixDomain, should_close, child_processes_inherit) {}
61 
62 DomainSocket::DomainSocket(SocketProtocol protocol,
63                            bool child_processes_inherit)
64     : Socket(protocol, true, child_processes_inherit) {}
65 
66 DomainSocket::DomainSocket(NativeSocket socket,
67                            const DomainSocket &listen_socket)
68     : Socket(ProtocolUnixDomain, listen_socket.m_should_close_fd,
69              listen_socket.m_child_processes_inherit) {
70   m_socket = socket;
71 }
72 
73 Status DomainSocket::Connect(llvm::StringRef name) {
74   sockaddr_un saddr_un;
75   socklen_t saddr_un_len;
76   if (!SetSockAddr(name, GetNameOffset(), &saddr_un, saddr_un_len))
77     return Status("Failed to set socket address");
78 
79   Status error;
80   m_socket = CreateSocket(kDomain, kType, 0, m_child_processes_inherit, error);
81   if (error.Fail())
82     return error;
83   if (llvm::sys::RetryAfterSignal(-1, ::connect, GetNativeSocket(),
84         (struct sockaddr *)&saddr_un, saddr_un_len) < 0)
85     SetLastError(error);
86 
87   return error;
88 }
89 
90 Status DomainSocket::Listen(llvm::StringRef name, int backlog) {
91   sockaddr_un saddr_un;
92   socklen_t saddr_un_len;
93   if (!SetSockAddr(name, GetNameOffset(), &saddr_un, saddr_un_len))
94     return Status("Failed to set socket address");
95 
96   DeleteSocketFile(name);
97 
98   Status error;
99   m_socket = CreateSocket(kDomain, kType, 0, m_child_processes_inherit, error);
100   if (error.Fail())
101     return error;
102   if (::bind(GetNativeSocket(), (struct sockaddr *)&saddr_un, saddr_un_len) ==
103       0)
104     if (::listen(GetNativeSocket(), backlog) == 0)
105       return error;
106 
107   SetLastError(error);
108   return error;
109 }
110 
111 Status DomainSocket::Accept(Socket *&socket) {
112   Status error;
113   auto conn_fd = AcceptSocket(GetNativeSocket(), nullptr, nullptr,
114                               m_child_processes_inherit, error);
115   if (error.Success())
116     socket = new DomainSocket(conn_fd, *this);
117 
118   return error;
119 }
120 
121 size_t DomainSocket::GetNameOffset() const { return 0; }
122 
123 void DomainSocket::DeleteSocketFile(llvm::StringRef name) {
124   llvm::sys::fs::remove(name);
125 }
126 
127 std::string DomainSocket::GetSocketName() const {
128   if (m_socket == kInvalidSocketValue)
129     return "";
130 
131   struct sockaddr_un saddr_un;
132   saddr_un.sun_family = AF_UNIX;
133   socklen_t sock_addr_len = sizeof(struct sockaddr_un);
134   if (::getpeername(m_socket, (struct sockaddr *)&saddr_un, &sock_addr_len) !=
135       0)
136     return "";
137 
138   if (sock_addr_len <= offsetof(struct sockaddr_un, sun_path))
139     return ""; // Unnamed domain socket
140 
141   llvm::StringRef name(saddr_un.sun_path + GetNameOffset(),
142                        sock_addr_len - offsetof(struct sockaddr_un, sun_path) -
143                            GetNameOffset());
144   name = name.rtrim('\0');
145 
146   return name.str();
147 }
148 
149 std::string DomainSocket::GetRemoteConnectionURI() const {
150   std::string name = GetSocketName();
151   if (name.empty())
152     return name;
153 
154   return llvm::formatv(
155       "{0}://{1}",
156       GetNameOffset() == 0 ? "unix-connect" : "unix-abstract-connect", name);
157 }
158