lib/system_override.c

   1 /*
   2  * Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
   3  * 2009, 2010, 2011 Free Software Foundation, Inc.
   4  *
   5  * Author: Nikos Mavrogiannopoulos
   6  *
   7  * This file is part of GnuTLS.
   8  *
   9  * The GnuTLS is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public License
  11  * as published by the Free Software Foundation; either version 3 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public License
  20  * along with this program.  If not, see <http://www.gnu.org/licenses/>
  21  *
  22  */
  23
  24 /* This file contains function that will override the
  25  * default berkeley sockets API per session.
  26  */
  27
  28 #include <gnutls_int.h>
  29 #include <gnutls_errors.h>
  30 #include <gnutls_num.h>
  31 #include <gnutls_record.h>
  32 #include <gnutls_buffers.h>
  33 #include <gnutls_mbuffers.h>
  34 #include <gnutls_state.h>
  35 #include <gnutls_dtls.h>
  36 #include <system.h>
  37
  38 #include <errno.h>
  39 #ifdef _WIN32
  40 # include <windows.h>
  41 #endif
  42
  43 /**
  44  * gnutls_transport_set_errno:
  45  * @session: is a #gnutls_session_t structure.
  46  * @err: error value to store in session-specific errno variable.
  47  *
  48  * Store @err in the session-specific errno variable.  Useful values
  49  * for @err is EAGAIN and EINTR, other values are treated will be
  50  * treated as real errors in the push/pull function.
  51  *
  52  * This function is useful in replacement push and pull functions set by
  53  * gnutls_transport_set_push_function() and
  54  * gnutls_transport_set_pull_function() under Windows, where the
  55  * replacements may not have access to the same @errno
  56  * variable that is used by GnuTLS (e.g., the application is linked to
  57  * msvcr71.dll and gnutls is linked to msvcrt.dll).
  58  *
  59  **/
  60 void
  61 gnutls_transport_set_errno (gnutls_session_t session, int err)
  62 {
  63   session->internals.errnum = err;
  64 }
  65
  66 /**
  67  * gnutls_transport_set_pull_function:
  68  * @session: is a #gnutls_session_t structure.
  69  * @pull_func: a callback function similar to read()
  70  *
  71  * This is the function where you set a function for gnutls to receive
  72  * data.  Normally, if you use berkeley style sockets, do not need to
  73  * use this function since the default recv(2) will probably be ok.
  74  * The callback should return 0 on connection termination, a positive
  75  * number indicating the number of bytes received, and -1 on error.
  76  *
  77  * @gnutls_pull_func is of the form,
  78  * ssize_t (*gnutls_pull_func)(gnutls_transport_ptr_t, void*, size_t);
  79  **/
  80 void
  81 gnutls_transport_set_pull_function (gnutls_session_t session,
  82                                     gnutls_pull_func pull_func)
  83 {
  84   session->internals.pull_func = pull_func;
  85 }
  86
  87 /**
  88  * gnutls_transport_set_pull_timeout_function:
  89  * @session: is a #gnutls_session_t structure.
  90  * @func: a callback function
  91  *
  92  * This is the function where you set a function for gnutls to know
  93  * whether data are ready to be received. It should wait for data a
  94  * given time frame in milliseconds. The callback should return 0 on
  95  * timeout, a positive number if data can be received, and -1 on error.
  96  * You'll need to override this function if select() is not suitable
  97  * for the provided transport calls.
  98  * The callback function is used in DTLS only.
  99  *
 100  * @gnutls_pull_timeout_func is of the form,
 101  * ssize_t (*gnutls_pull_timeout_func)(gnutls_transport_ptr_t, unsigned int ms);
 102  *
 103  * Since: 3.0.0
 104  **/
 105 void
 106 gnutls_transport_set_pull_timeout_function (gnutls_session_t session,
 107                                             gnutls_pull_timeout_func func)
 108 {
 109   session->internals.pull_timeout_func = func;
 110 }
 111
 112 /**
 113  * gnutls_transport_set_push_function:
 114  * @session: is a #gnutls_session_t structure.
 115  * @push_func: a callback function similar to write()
 116  *
 117  * This is the function where you set a push function for gnutls to
 118  * use in order to send data.  If you are going to use berkeley style
 119  * sockets, you do not need to use this function since the default
 120  * send(2) will probably be ok.  Otherwise you should specify this
 121  * function for gnutls to be able to send data.
 122  * The callback should return a positive number indicating the
 123  * bytes sent, and -1 on error.
 124  *
 125  * @push_func is of the form,
 126  * ssize_t (*gnutls_push_func)(gnutls_transport_ptr_t, const void*, size_t);
 127  *
 128  **/
 129 void
 130 gnutls_transport_set_push_function (gnutls_session_t session,
 131                                     gnutls_push_func push_func)
 132 {
 133   session->internals.push_func = push_func;
 134   session->internals.vec_push_func = NULL;
 135 }
 136
 137 /**
 138  * gnutls_transport_set_vec_push_function:
 139  * @session: is a #gnutls_session_t structure.
 140  * @vec_func: a callback function similar to writev()
 141  *
 142  * Using this function you can override the default writev(2)
 143  * function for gnutls to send data. Setting this callback
 144  * instead of gnutls_transport_set_push_function() is recommended
 145  * since it introduces less overhead in the TLS handshake process.
 146  *
 147  * @vec_func is of the form,
 148  * ssize_t (*gnutls_vec_push_func) (gnutls_transport_ptr_t, const giovec_t * iov, int iovcnt);
 149  *
 150  * Since: 2.12.0
 151  **/
 152 void
 153 gnutls_transport_set_vec_push_function (gnutls_session_t session,
 154                                         gnutls_vec_push_func vec_func)
 155 {
 156   session->internals.push_func = NULL;
 157   session->internals.vec_push_func = vec_func;
 158 }
 159
 160 /**
 161  * gnutls_transport_set_errno_function:
 162  * @session: is a #gnutls_session_t structure.
 163  * @errno_func: a callback function similar to write()
 164  *
 165  * This is the function where you set a function to retrieve errno
 166  * after a failed push or pull operation.
 167  *
 168  * @errno_func is of the form,
 169  * int (*gnutls_errno_func)(gnutls_transport_ptr_t);
 170  * and should return the errno.
 171  *
 172  * Since: 2.12.0
 173  **/
 174 void
 175 gnutls_transport_set_errno_function (gnutls_session_t session,
 176                                      gnutls_errno_func errno_func)
 177 {
 178   session->internals.errno_func = errno_func;
 179 }