xapian-core/net/tcpclient.cc

   1 /* tcpclient.cc: Open a TCP connection to a server.
   2  *
   3  * Copyright 1999,2000,2001 BrightStation PLC
   4  * Copyright 2002 Ananova Ltd
   5  * Copyright 2004,2005,2006,2007,2008,2010,2012,2013,2015,2017 Olly Betts
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
  20  * USA
  21  */
  22
  23 #include <config.h>
  24
  25 #include "tcpclient.h"
  26
  27 #include "remoteconnection.h"
  28 #include "resolver.h"
  29 #include "str.h"
  30 #include <xapian/error.h>
  31
  32 #include "realtime.h"
  33 #include "safeerrno.h"
  34 #include "safefcntl.h"
  35 #include "safenetdb.h"
  36 #include "safesysselect.h"
  37 #include "safesyssocket.h"
  38 #include "socket_utils.h"
  39
  40 #include <cmath>
  41 #include <cstring>
  42 #ifndef __WIN32__
  43 # include <netinet/in.h>
  44 # include <netinet/tcp.h>
  45 #endif
  46
  47 using namespace std;
  48
  49 int
  50 TcpClient::open_socket(const std::string & hostname, int port,
  51                        double timeout_connect, bool tcp_nodelay)
  52 {
  53     int socketfd = -1;
  54     int connect_errno = 0;
  55     for (auto&& r : Resolver(hostname, port)) {
  56         int socktype = r.ai_socktype | SOCK_CLOEXEC;
  57         int fd = socket(r.ai_family, socktype, r.ai_protocol);
  58         if (fd == -1)
  59             continue;
  60
  61 #if !defined __WIN32__ && defined F_SETFD && defined FD_CLOEXEC
  62         // We can't use a preprocessor check on the *value* of SOCK_CLOEXEC as
  63         // on Linux SOCK_CLOEXEC is an enum, with '#define SOCK_CLOEXEC
  64         // SOCK_CLOEXEC' to allow '#ifdef SOCK_CLOEXEC' to work.
  65         if (SOCK_CLOEXEC == 0)
  66             (void)fcntl(fd, F_SETFD, FD_CLOEXEC);
  67 #endif
  68
  69 #ifdef __WIN32__
  70         ULONG enabled = 1;
  71         int rc = ioctlsocket(fd, FIONBIO, &enabled);
  72 #define FLAG_NAME "FIONBIO"
  73 #elif defined O_NONBLOCK
  74         int rc = fcntl(fd, F_SETFL, O_NONBLOCK);
  75 #define FLAG_NAME "O_NONBLOCK"
  76 #else
  77         int rc = fcntl(fd, F_SETFL, O_NDELAY);
  78 #define FLAG_NAME "O_NDELAY"
  79 #endif
  80         if (rc < 0) {
  81             int saved_errno = socket_errno(); // note down in case close hits an error
  82             close_fd_or_socket(fd);
  83             throw Xapian::NetworkError("Couldn't set " FLAG_NAME, saved_errno);
  84 #undef FLAG_NAME
  85         }
  86
  87         if (tcp_nodelay) {
  88             int optval = 1;
  89             // 4th argument might need to be void* or char* - cast it to char*
  90             // since C++ allows implicit conversion to void* but not from
  91             // void*.
  92             if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY,
  93                            reinterpret_cast<char *>(&optval),
  94                            sizeof(optval)) < 0) {
  95                 int saved_errno = socket_errno(); // note down in case close hits an error
  96                 close_fd_or_socket(fd);
  97                 throw Xapian::NetworkError("Couldn't set TCP_NODELAY", saved_errno);
  98             }
  99         }
 100
 101         int retval = connect(fd, r.ai_addr, r.ai_addrlen);
 102         if (retval == 0) {
 103             socketfd = fd;
 104             break;
 105         }
 106
 107         int err = socket_errno();
 108         if (
 109 #ifdef __WIN32__
 110             WSAGetLastError() == WSAEWOULDBLOCK
 111 #else
 112             err == EINPROGRESS
 113 #endif
 114             ) {
 115             // Wait for the socket to be writable, with a timeout.
 116             fd_set fdset;
 117             FD_ZERO(&fdset);
 118             FD_SET(fd, &fdset);
 119
 120             do {
 121                 // FIXME: Reduce the timeout if we retry on EINTR.
 122                 struct timeval tv;
 123                 RealTime::to_timeval(timeout_connect, &tv);
 124                 retval = select(fd + 1, 0, &fdset, &fdset, &tv);
 125             } while (retval < 0 && (errno == EINTR || errno == EAGAIN));
 126
 127             if (retval <= 0) {
 128                 int saved_errno = errno;
 129                 close_fd_or_socket(fd);
 130                 if (retval < 0)
 131                     throw Xapian::NetworkError("Couldn't connect (select() on socket failed)",
 132                                                saved_errno);
 133                 throw Xapian::NetworkTimeoutError("Timed out waiting to connect", ETIMEDOUT);
 134             }
 135
 136             err = 0;
 137             SOCKLEN_T len = sizeof(err);
 138
 139             // 4th argument might need to be void* or char* - cast it to char*
 140             // since C++ allows implicit conversion to void* but not from void*.
 141             retval = getsockopt(fd, SOL_SOCKET, SO_ERROR,
 142                                 reinterpret_cast<char *>(&err), &len);
 143
 144             if (retval < 0) {
 145                 int saved_errno = socket_errno(); // note down in case close hits an error
 146                 close_fd_or_socket(fd);
 147                 throw Xapian::NetworkError("Couldn't get socket options", saved_errno);
 148             }
 149             if (err == 0) {
 150                 // Connected successfully.
 151                 socketfd = fd;
 152                 break;
 153             }
 154         }
 155
 156         // Note down the error code for the first address we try, which seems
 157         // likely to be more helpful than the last in the case where they
 158         // differ.
 159         if (connect_errno == 0)
 160             connect_errno = err;
 161
 162         // Failed to connect.
 163         CLOSESOCKET(fd);
 164     }
 165
 166     if (socketfd == -1) {
 167         throw Xapian::NetworkError("Couldn't connect", connect_errno);
 168     }
 169
 170 #ifdef __WIN32__
 171     ULONG enabled = 0;
 172     ioctlsocket(socketfd, FIONBIO, &enabled);
 173 #else
 174     fcntl(socketfd, F_SETFL, 0);
 175 #endif
 176     return socketfd;
 177 }
 178
 179 #ifdef DISABLE_GPL_LIBXAPIAN
 180 # error GPL source we cannot relicense included in libxapian
 181 #endif