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| 1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #include "base/posix/unix_domain_socket_linux.h" | |
| 6 | |
| 7 #include <errno.h> | |
| 8 #include <sys/socket.h> | |
| 9 #include <unistd.h> | |
| 10 | |
| 11 #include <vector> | |
| 12 | |
| 13 #include "base/files/scoped_file.h" | |
| 14 #include "base/logging.h" | |
| 15 #include "base/memory/scoped_vector.h" | |
| 16 #include "base/pickle.h" | |
| 17 #include "base/posix/eintr_wrapper.h" | |
| 18 #include "base/stl_util.h" | |
| 19 | |
| 20 #if !defined(OS_NACL_NONSFI) | |
| 21 #include <sys/uio.h> | |
| 22 #endif | |
| 23 | |
| 24 namespace base { | |
| 25 | |
| 26 const size_t UnixDomainSocket::kMaxFileDescriptors = 16; | |
| 27 | |
| 28 #if !defined(OS_NACL_NONSFI) | |
| 29 // Creates a connected pair of UNIX-domain SOCK_SEQPACKET sockets, and passes | |
| 30 // ownership of the newly allocated file descriptors to |one| and |two|. | |
| 31 // Returns true on success. | |
| 32 static bool CreateSocketPair(ScopedFD* one, ScopedFD* two) { | |
| 33 int raw_socks[2]; | |
| 34 if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, raw_socks) == -1) | |
| 35 return false; | |
| 36 one->reset(raw_socks[0]); | |
| 37 two->reset(raw_socks[1]); | |
| 38 return true; | |
| 39 } | |
| 40 | |
| 41 // static | |
| 42 bool UnixDomainSocket::EnableReceiveProcessId(int fd) { | |
| 43 const int enable = 1; | |
| 44 return setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable)) == 0; | |
| 45 } | |
| 46 #endif // !defined(OS_NACL_NONSFI) | |
| 47 | |
| 48 // static | |
| 49 bool UnixDomainSocket::SendMsg(int fd, | |
| 50 const void* buf, | |
| 51 size_t length, | |
| 52 const std::vector<int>& fds) { | |
| 53 struct msghdr msg = {}; | |
| 54 struct iovec iov = { const_cast<void*>(buf), length }; | |
| 55 msg.msg_iov = &iov; | |
| 56 msg.msg_iovlen = 1; | |
| 57 | |
| 58 char* control_buffer = NULL; | |
| 59 if (fds.size()) { | |
| 60 const unsigned control_len = CMSG_SPACE(sizeof(int) * fds.size()); | |
| 61 control_buffer = new char[control_len]; | |
| 62 | |
| 63 struct cmsghdr* cmsg; | |
| 64 msg.msg_control = control_buffer; | |
| 65 msg.msg_controllen = control_len; | |
| 66 cmsg = CMSG_FIRSTHDR(&msg); | |
| 67 cmsg->cmsg_level = SOL_SOCKET; | |
| 68 cmsg->cmsg_type = SCM_RIGHTS; | |
| 69 cmsg->cmsg_len = CMSG_LEN(sizeof(int) * fds.size()); | |
| 70 memcpy(CMSG_DATA(cmsg), &fds[0], sizeof(int) * fds.size()); | |
| 71 msg.msg_controllen = cmsg->cmsg_len; | |
| 72 } | |
| 73 | |
| 74 // Avoid a SIGPIPE if the other end breaks the connection. | |
| 75 // Due to a bug in the Linux kernel (net/unix/af_unix.c) MSG_NOSIGNAL isn't | |
| 76 // regarded for SOCK_SEQPACKET in the AF_UNIX domain, but it is mandated by | |
| 77 // POSIX. | |
| 78 const int flags = MSG_NOSIGNAL; | |
| 79 const ssize_t r = HANDLE_EINTR(sendmsg(fd, &msg, flags)); | |
| 80 const bool ret = static_cast<ssize_t>(length) == r; | |
| 81 delete[] control_buffer; | |
| 82 return ret; | |
| 83 } | |
| 84 | |
| 85 // static | |
| 86 ssize_t UnixDomainSocket::RecvMsg(int fd, | |
| 87 void* buf, | |
| 88 size_t length, | |
| 89 ScopedVector<ScopedFD>* fds) { | |
| 90 return UnixDomainSocket::RecvMsgWithPid(fd, buf, length, fds, NULL); | |
| 91 } | |
| 92 | |
| 93 // static | |
| 94 ssize_t UnixDomainSocket::RecvMsgWithPid(int fd, | |
| 95 void* buf, | |
| 96 size_t length, | |
| 97 ScopedVector<ScopedFD>* fds, | |
| 98 ProcessId* pid) { | |
| 99 return UnixDomainSocket::RecvMsgWithFlags(fd, buf, length, 0, fds, pid); | |
| 100 } | |
| 101 | |
| 102 // static | |
| 103 ssize_t UnixDomainSocket::RecvMsgWithFlags(int fd, | |
| 104 void* buf, | |
| 105 size_t length, | |
| 106 int flags, | |
| 107 ScopedVector<ScopedFD>* fds, | |
| 108 ProcessId* out_pid) { | |
| 109 fds->clear(); | |
| 110 | |
| 111 struct msghdr msg = {}; | |
| 112 struct iovec iov = { buf, length }; | |
| 113 msg.msg_iov = &iov; | |
| 114 msg.msg_iovlen = 1; | |
| 115 | |
| 116 const size_t kControlBufferSize = | |
| 117 CMSG_SPACE(sizeof(int) * kMaxFileDescriptors) | |
| 118 #if !defined(OS_NACL_NONSFI) | |
| 119 // The PNaCl toolchain for Non-SFI binary build does not support ucred. | |
| 120 + CMSG_SPACE(sizeof(struct ucred)) | |
| 121 #endif | |
| 122 ; | |
| 123 char control_buffer[kControlBufferSize]; | |
| 124 msg.msg_control = control_buffer; | |
| 125 msg.msg_controllen = sizeof(control_buffer); | |
| 126 | |
| 127 const ssize_t r = HANDLE_EINTR(recvmsg(fd, &msg, flags)); | |
| 128 if (r == -1) | |
| 129 return -1; | |
| 130 | |
| 131 int* wire_fds = NULL; | |
| 132 unsigned wire_fds_len = 0; | |
| 133 ProcessId pid = -1; | |
| 134 | |
| 135 if (msg.msg_controllen > 0) { | |
| 136 struct cmsghdr* cmsg; | |
| 137 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { | |
| 138 const unsigned payload_len = cmsg->cmsg_len - CMSG_LEN(0); | |
| 139 if (cmsg->cmsg_level == SOL_SOCKET && | |
| 140 cmsg->cmsg_type == SCM_RIGHTS) { | |
| 141 DCHECK_EQ(payload_len % sizeof(int), 0u); | |
| 142 DCHECK_EQ(wire_fds, static_cast<void*>(nullptr)); | |
| 143 wire_fds = reinterpret_cast<int*>(CMSG_DATA(cmsg)); | |
| 144 wire_fds_len = payload_len / sizeof(int); | |
| 145 } | |
| 146 #if !defined(OS_NACL_NONSFI) | |
| 147 // The PNaCl toolchain for Non-SFI binary build does not support | |
| 148 // SCM_CREDENTIALS. | |
| 149 if (cmsg->cmsg_level == SOL_SOCKET && | |
| 150 cmsg->cmsg_type == SCM_CREDENTIALS) { | |
| 151 DCHECK_EQ(payload_len, sizeof(struct ucred)); | |
| 152 DCHECK_EQ(pid, -1); | |
| 153 pid = reinterpret_cast<struct ucred*>(CMSG_DATA(cmsg))->pid; | |
| 154 } | |
| 155 #endif | |
| 156 } | |
| 157 } | |
| 158 | |
| 159 if (msg.msg_flags & MSG_TRUNC || msg.msg_flags & MSG_CTRUNC) { | |
| 160 for (unsigned i = 0; i < wire_fds_len; ++i) | |
| 161 close(wire_fds[i]); | |
| 162 errno = EMSGSIZE; | |
| 163 return -1; | |
| 164 } | |
| 165 | |
| 166 if (wire_fds) { | |
| 167 for (unsigned i = 0; i < wire_fds_len; ++i) | |
| 168 fds->push_back(new ScopedFD(wire_fds[i])); | |
| 169 } | |
| 170 | |
| 171 if (out_pid) { | |
| 172 // |pid| will legitimately be -1 if we read EOF, so only DCHECK if we | |
| 173 // actually received a message. Unfortunately, Linux allows sending zero | |
| 174 // length messages, which are indistinguishable from EOF, so this check | |
| 175 // has false negatives. | |
| 176 if (r > 0 || msg.msg_controllen > 0) | |
| 177 DCHECK_GE(pid, 0); | |
| 178 | |
| 179 *out_pid = pid; | |
| 180 } | |
| 181 | |
| 182 return r; | |
| 183 } | |
| 184 | |
| 185 #if !defined(OS_NACL_NONSFI) | |
| 186 // static | |
| 187 ssize_t UnixDomainSocket::SendRecvMsg(int fd, | |
| 188 uint8_t* reply, | |
| 189 unsigned max_reply_len, | |
| 190 int* result_fd, | |
| 191 const Pickle& request) { | |
| 192 return UnixDomainSocket::SendRecvMsgWithFlags(fd, reply, max_reply_len, | |
| 193 0, /* recvmsg_flags */ | |
| 194 result_fd, request); | |
| 195 } | |
| 196 | |
| 197 // static | |
| 198 ssize_t UnixDomainSocket::SendRecvMsgWithFlags(int fd, | |
| 199 uint8_t* reply, | |
| 200 unsigned max_reply_len, | |
| 201 int recvmsg_flags, | |
| 202 int* result_fd, | |
| 203 const Pickle& request) { | |
| 204 // This socketpair is only used for the IPC and is cleaned up before | |
| 205 // returning. | |
| 206 ScopedFD recv_sock, send_sock; | |
| 207 if (!CreateSocketPair(&recv_sock, &send_sock)) | |
| 208 return -1; | |
| 209 | |
| 210 { | |
| 211 std::vector<int> send_fds; | |
| 212 send_fds.push_back(send_sock.get()); | |
| 213 if (!SendMsg(fd, request.data(), request.size(), send_fds)) | |
| 214 return -1; | |
| 215 } | |
| 216 | |
| 217 // Close the sending end of the socket right away so that if our peer closes | |
| 218 // it before sending a response (e.g., from exiting), RecvMsgWithFlags() will | |
| 219 // return EOF instead of hanging. | |
| 220 send_sock.reset(); | |
| 221 | |
| 222 ScopedVector<ScopedFD> recv_fds; | |
| 223 // When porting to OSX keep in mind it doesn't support MSG_NOSIGNAL, so the | |
| 224 // sender might get a SIGPIPE. | |
| 225 const ssize_t reply_len = RecvMsgWithFlags( | |
| 226 recv_sock.get(), reply, max_reply_len, recvmsg_flags, &recv_fds, NULL); | |
| 227 recv_sock.reset(); | |
| 228 if (reply_len == -1) | |
| 229 return -1; | |
| 230 | |
| 231 // If we received more file descriptors than caller expected, then we treat | |
| 232 // that as an error. | |
| 233 if (recv_fds.size() > (result_fd != NULL ? 1 : 0)) { | |
| 234 NOTREACHED(); | |
| 235 return -1; | |
| 236 } | |
| 237 | |
| 238 if (result_fd) | |
| 239 *result_fd = recv_fds.empty() ? -1 : recv_fds[0]->release(); | |
| 240 | |
| 241 return reply_len; | |
| 242 } | |
| 243 #endif // !defined(OS_NACL_NONSFI) | |
| 244 | |
| 245 } // namespace base | |
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