1.\" $OpenBSD: SSL_want.3,v 1.5 2018/03/27 17:35:50 schwarze Exp $ 2.\" OpenSSL 9b86974e Aug 17 15:21:33 2015 -0400 3.\" 4.\" This file was written by Lutz Jaenicke <jaenicke@openssl.org>. 5.\" Copyright (c) 2001, 2005 The OpenSSL Project. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in 16.\" the documentation and/or other materials provided with the 17.\" distribution. 18.\" 19.\" 3. All advertising materials mentioning features or use of this 20.\" software must display the following acknowledgment: 21.\" "This product includes software developed by the OpenSSL Project 22.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 23.\" 24.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 25.\" endorse or promote products derived from this software without 26.\" prior written permission. For written permission, please contact 27.\" openssl-core@openssl.org. 28.\" 29.\" 5. Products derived from this software may not be called "OpenSSL" 30.\" nor may "OpenSSL" appear in their names without prior written 31.\" permission of the OpenSSL Project. 32.\" 33.\" 6. Redistributions of any form whatsoever must retain the following 34.\" acknowledgment: 35.\" "This product includes software developed by the OpenSSL Project 36.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)" 37.\" 38.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 39.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 40.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 41.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 42.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 43.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 44.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 45.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 46.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 47.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 48.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 49.\" OF THE POSSIBILITY OF SUCH DAMAGE. 50.\" 51.Dd $Mdocdate: March 27 2018 $ 52.Dt SSL_WANT 3 53.Os 54.Sh NAME 55.Nm SSL_want , 56.Nm SSL_want_nothing , 57.Nm SSL_want_read , 58.Nm SSL_want_write , 59.Nm SSL_want_x509_lookup 60.Nd obtain state information TLS/SSL I/O operation 61.Sh SYNOPSIS 62.In openssl/ssl.h 63.Ft int 64.Fn SSL_want "const SSL *ssl" 65.Ft int 66.Fn SSL_want_nothing "const SSL *ssl" 67.Ft int 68.Fn SSL_want_read "const SSL *ssl" 69.Ft int 70.Fn SSL_want_write "const SSL *ssl" 71.Ft int 72.Fn SSL_want_x509_lookup "const SSL *ssl" 73.Sh DESCRIPTION 74.Fn SSL_want 75returns state information for the 76.Vt SSL 77object 78.Fa ssl . 79.Pp 80The other 81.Fn SSL_want_* 82calls are shortcuts for the possible states returned by 83.Fn SSL_want . 84.Pp 85.Fn SSL_want 86examines the internal state information of the 87.Vt SSL 88object. 89Its return values are similar to those of 90.Xr SSL_get_error 3 . 91Unlike 92.Xr SSL_get_error 3 , 93which also evaluates the error queue, 94the results are obtained by examining an internal state flag only. 95The information must therefore only be used for normal operation under 96non-blocking I/O. 97Error conditions are not handled and must be treated using 98.Xr SSL_get_error 3 . 99.Pp 100The result returned by 101.Fn SSL_want 102should always be consistent with the result of 103.Xr SSL_get_error 3 . 104.Sh RETURN VALUES 105The following return values can currently occur for 106.Fn SSL_want : 107.Bl -tag -width Ds 108.It Dv SSL_NOTHING 109There is no data to be written or to be read. 110.It Dv SSL_WRITING 111There are data in the SSL buffer that must be written to the underlying 112.Vt BIO 113layer in order to complete the actual 114.Fn SSL_* 115operation. 116A call to 117.Xr SSL_get_error 3 118should return 119.Dv SSL_ERROR_WANT_WRITE . 120.It Dv SSL_READING 121More data must be read from the underlying 122.Vt BIO 123layer in order to 124complete the actual 125.Fn SSL_* 126operation. 127A call to 128.Xr SSL_get_error 3 129should return 130.Dv SSL_ERROR_WANT_READ . 131.It Dv SSL_X509_LOOKUP 132The operation did not complete because an application callback set by 133.Xr SSL_CTX_set_client_cert_cb 3 134has asked to be called again. 135A call to 136.Xr SSL_get_error 3 137should return 138.Dv SSL_ERROR_WANT_X509_LOOKUP . 139.El 140.Pp 141.Fn SSL_want_nothing , 142.Fn SSL_want_read , 143.Fn SSL_want_write , 144and 145.Fn SSL_want_x509_lookup 146return 1 when the corresponding condition is true or 0 otherwise. 147.Sh SEE ALSO 148.Xr err 3 , 149.Xr ssl 3 , 150.Xr SSL_get_error 3 151.Sh HISTORY 152.Fn SSL_want , 153.Fn SSL_want_nothing , 154.Fn SSL_want_read , 155and 156.Fn SSL_want_write 157first appeared in SSLeay 0.5.2. 158.Fn SSL_want_x509_lookup 159first appeared in SSLeay 0.6.0. 160These functions have been available since 161.Ox 2.4 . 162