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 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 "str.h"
  29 #include <xapian/error.h>
  30
  31 #include "realtime.h"
  32 #include "safeerrno.h"
  33 #include "safefcntl.h"
  34 #include "safenetdb.h"
  35 #include "safesysselect.h"
  36 #include "safesyssocket.h"
  37 #include "socket_utils.h"
  38
  39 #include <cmath>
  40 #include <cstring>
  41 #ifndef __WIN32__
  42 # include <netinet/in.h>
  43 # include <netinet/tcp.h>
  44 #endif
  45
  46 using namespace std;
  47
  48 int
  49 TcpClient::open_socket(const std::string & hostname, int port,
  50                        double timeout_connect, bool tcp_nodelay)
  51 {
  52     struct addrinfo hints;
  53     memset(&hints, 0, sizeof(struct addrinfo));
  54     hints.ai_family = AF_INET;
  55     hints.ai_socktype = SOCK_STREAM;
  56     hints.ai_flags = AI_ADDRCONFIG | AI_NUMERICSERV;
  57     hints.ai_protocol = 0;
  58
  59     struct addrinfo *result;
  60     int s = getaddrinfo(hostname.c_str(), str(port).c_str(), &hints, &result);
  61     if (s != 0) {
  62         throw Xapian::NetworkError("Couldn't resolve host " + hostname,
  63                                    eai_to_xapian(s));
  64     }
  65
  66     int connect_errno = 0;
  67     int socketfd = -1;
  68     for (struct addrinfo * rp = result; rp != NULL; rp = rp->ai_next) {
  69         int socktype = rp->ai_socktype | SOCK_CLOEXEC;
  70         int fd = socket(rp->ai_family, socktype, rp->ai_protocol);
  71         if (fd == -1)
  72             continue;
  73
  74 #if !defined __WIN32__ && defined F_SETFD && defined FD_CLOEXEC
  75         // We can't use a preprocessor check on the *value* of SOCK_CLOEXEC as
  76         // on Linux SOCK_CLOEXEC is an enum, with '#define SOCK_CLOEXEC
  77         // SOCK_CLOEXEC' to allow '#ifdef SOCK_CLOEXEC' to work.
  78         if (SOCK_CLOEXEC == 0)
  79             (void)fcntl(fd, F_SETFD, FD_CLOEXEC);
  80 #endif
  81
  82 #ifdef __WIN32__
  83         ULONG enabled = 1;
  84         int rc = ioctlsocket(fd, FIONBIO, &enabled);
  85 #define FLAG_NAME "FIONBIO"
  86 #elif defined O_NONBLOCK
  87         int rc = fcntl(fd, F_SETFL, O_NONBLOCK);
  88 #define FLAG_NAME "O_NONBLOCK"
  89 #else
  90         int rc = fcntl(fd, F_SETFL, O_NDELAY);
  91 #define FLAG_NAME "O_NDELAY"
  92 #endif
  93         if (rc < 0) {
  94             int saved_errno = socket_errno(); // note down in case close hits an error
  95             close_fd_or_socket(fd);
  96             freeaddrinfo(result);
  97             throw Xapian::NetworkError("Couldn't set " FLAG_NAME, saved_errno);
  98 #undef FLAG_NAME
  99         }
 100
 101         if (tcp_nodelay) {
 102             int optval = 1;
 103             // 4th argument might need to be void* or char* - cast it to char*
 104             // since C++ allows implicit conversion to void* but not from
 105             // void*.
 106             if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY,
 107                            reinterpret_cast<char *>(&optval),
 108                            sizeof(optval)) < 0) {
 109                 int saved_errno = socket_errno(); // note down in case close hits an error
 110                 close_fd_or_socket(fd);
 111                 freeaddrinfo(result);
 112                 throw Xapian::NetworkError("Couldn't set TCP_NODELAY", saved_errno);
 113             }
 114         }
 115
 116         int retval = connect(fd, rp->ai_addr, rp->ai_addrlen);
 117         if (retval == 0) {
 118             socketfd = fd;
 119             break;
 120         }
 121
 122         int err = socket_errno();
 123         if (
 124 #ifdef __WIN32__
 125             WSAGetLastError() == WSAEWOULDBLOCK
 126 #else
 127             err == EINPROGRESS
 128 #endif
 129             ) {
 130             // Wait for the socket to be writable, with a timeout.
 131             fd_set fdset;
 132             FD_ZERO(&fdset);
 133             FD_SET(fd, &fdset);
 134
 135             do {
 136                 // FIXME: Reduce the timeout if we retry on EINTR.
 137                 struct timeval tv;
 138                 RealTime::to_timeval(timeout_connect, &tv);
 139                 retval = select(fd + 1, 0, &fdset, &fdset, &tv);
 140             } while (retval < 0 && errno == EINTR);
 141
 142             if (retval <= 0) {
 143                 int saved_errno = errno;
 144                 close_fd_or_socket(fd);
 145                 freeaddrinfo(result);
 146                 if (retval < 0)
 147                     throw Xapian::NetworkError("Couldn't connect (select() on socket failed)",
 148                                                saved_errno);
 149                 throw Xapian::NetworkTimeoutError("Timed out waiting to connect", ETIMEDOUT);
 150             }
 151
 152             err = 0;
 153             SOCKLEN_T len = sizeof(err);
 154
 155             // 4th argument might need to be void* or char* - cast it to char*
 156             // since C++ allows implicit conversion to void* but not from void*.
 157             retval = getsockopt(fd, SOL_SOCKET, SO_ERROR,
 158                                 reinterpret_cast<char *>(&err), &len);
 159
 160             if (retval < 0) {
 161                 int saved_errno = socket_errno(); // note down in case close hits an error
 162                 close_fd_or_socket(fd);
 163                 freeaddrinfo(result);
 164                 throw Xapian::NetworkError("Couldn't get socket options", saved_errno);
 165             }
 166             if (err == 0) {
 167                 // Connected successfully.
 168                 socketfd = fd;
 169                 break;
 170             }
 171         }
 172
 173         // Note down the error code for the first address we try, which seems
 174         // likely to be more helpful than the last in the case where they
 175         // differ.
 176         if (connect_errno == 0)
 177             connect_errno = err;
 178
 179         // Failed to connect.
 180         CLOSESOCKET(fd);
 181     }
 182
 183     freeaddrinfo(result);
 184
 185     if (socketfd == -1) {
 186         throw Xapian::NetworkError("Couldn't connect", connect_errno);
 187     }
 188
 189 #ifdef __WIN32__
 190     ULONG enabled = 0;
 191     ioctlsocket(socketfd, FIONBIO, &enabled);
 192 #else
 193     fcntl(socketfd, F_SETFL, 0);
 194 #endif
 195     return socketfd;
 196 }