NetBSD/lib/libcrypto/man/SSL_get_error.3
2002-08-09 16:15:36 +00:00

243 lines
8.9 KiB
Groff

.\" $NetBSD: SSL_get_error.3,v 1.10 2002/08/09 16:15:43 itojun Exp $
.\"
.\" Automatically generated by Pod::Man version 1.02
.\" Sat Aug 10 00:58:36 2002
.\"
.\" Standard preamble:
.\" ======================================================================
.de Sh \" Subsection heading
.br
.if t .Sp
.ne 5
.PP
\fB\\$1\fR
.PP
..
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Ip \" List item
.br
.ie \\n(.$>=3 .ne \\$3
.el .ne 3
.IP "\\$1" \\$2
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings. \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote. | will give a
.\" real vertical bar. \*(C+ will give a nicer C++. Capital omega is used
.\" to do unbreakable dashes and therefore won't be available. \*(C` and
.\" \*(C' expand to `' in nroff, nothing in troff, for use with C<>
.tr \(*W-|\(bv\*(Tr
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
. ds -- \(*W-
. ds PI pi
. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
. ds L" ""
. ds R" ""
. ds C` `
. ds C' '
'br\}
.el\{\
. ds -- \|\(em\|
. ds PI \(*p
. ds L" ``
. ds R" ''
'br\}
.\"
.\" If the F register is turned on, we'll generate index entries on stderr
.\" for titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and
.\" index entries marked with X<> in POD. Of course, you'll have to process
.\" the output yourself in some meaningful fashion.
.if \nF \{\
. de IX
. tm Index:\\$1\t\\n%\t"\\$2"
. .
. nr % 0
. rr F
.\}
.\"
.\" For nroff, turn off justification. Always turn off hyphenation; it
.\" makes way too many mistakes in technical documents.
.hy 0
.if n .na
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear. Run. Save yourself. No user-serviceable parts.
.bd B 3
. \" fudge factors for nroff and troff
.if n \{\
. ds #H 0
. ds #V .8m
. ds #F .3m
. ds #[ \f1
. ds #] \fP
.\}
.if t \{\
. ds #H ((1u-(\\\\n(.fu%2u))*.13m)
. ds #V .6m
. ds #F 0
. ds #[ \&
. ds #] \&
.\}
. \" simple accents for nroff and troff
.if n \{\
. ds ' \&
. ds ` \&
. ds ^ \&
. ds , \&
. ds ~ ~
. ds /
.\}
.if t \{\
. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
. ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
. \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
. \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
. \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
. ds : e
. ds 8 ss
. ds o a
. ds d- d\h'-1'\(ga
. ds D- D\h'-1'\(hy
. ds th \o'bp'
. ds Th \o'LP'
. ds ae ae
. ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ======================================================================
.\"
.IX Title "SSL_get_error 3"
.TH SSL_get_error 3 "0.9.6g" "2002-07-31" "OpenSSL"
.UC
.SH "NAME"
SSL_get_error \- obtain result code for \s-1TLS/SSL\s0 I/O operation
.SH "LIBRARY"
libcrypto, -lcrypto
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/ssl.h>
.Ve
.Vb 1
\& int SSL_get_error(SSL *ssl, int ret);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fISSL_get_error()\fR returns a result code (suitable for the C \*(L"switch\*(R"
statement) for a preceding call to \fISSL_connect()\fR, \fISSL_accept()\fR, \fISSL_do_handshake()\fR,
\&\fISSL_read()\fR, \fISSL_peek()\fR, or \fISSL_write()\fR on \fBssl\fR. The value returned by
that \s-1TLS/SSL\s0 I/O function must be passed to \fISSL_get_error()\fR in parameter
\&\fBret\fR.
.PP
In addition to \fBssl\fR and \fBret\fR, \fISSL_get_error()\fR inspects the
current thread's OpenSSL error queue. Thus, \fISSL_get_error()\fR must be
used in the same thread that performed the \s-1TLS/SSL\s0 I/O operation, and no
other OpenSSL function calls should appear in between. The current
thread's error queue must be empty before the \s-1TLS/SSL\s0 I/O operation is
attempted, or \fISSL_get_error()\fR will not work reliably.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
The following return values can currently occur:
.Ip "\s-1SSL_ERROR_NONE\s0" 4
.IX Item "SSL_ERROR_NONE"
The \s-1TLS/SSL\s0 I/O operation completed. This result code is returned
if and only if \fBret > 0\fR.
.Ip "\s-1SSL_ERROR_ZERO_RETURN\s0" 4
.IX Item "SSL_ERROR_ZERO_RETURN"
The \s-1TLS/SSL\s0 connection has been closed. If the protocol version is \s-1SSL\s0 3.0
or \s-1TLS\s0 1.0, this result code is returned only if a closure
alert has occurred in the protocol, i.e. if the connection has been
closed cleanly. Note that in this case \fB\s-1SSL_ERROR_ZERO_RETURN\s0\fR
does not necessarily indicate that the underlying transport
has been closed.
.Ip "\s-1SSL_ERROR_WANT_READ\s0, \s-1SSL_ERROR_WANT_WRITE\s0" 4
.IX Item "SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE"
The operation did not complete; the same \s-1TLS/SSL\s0 I/O function should be
called again later. If, by then, the underlying \fB\s-1BIO\s0\fR has data
available for reading (if the result code is \fB\s-1SSL_ERROR_WANT_READ\s0\fR)
or allows writing data (\fB\s-1SSL_ERROR_WANT_WRITE\s0\fR), then some \s-1TLS/SSL\s0
protocol progress will take place, i.e. at least part of an \s-1TLS/SSL\s0
record will be read or written. Note that the retry may again lead to
a \fB\s-1SSL_ERROR_WANT_READ\s0\fR or \fB\s-1SSL_ERROR_WANT_WRITE\s0\fR condition.
There is no fixed upper limit for the number of iterations that
may be necessary until progress becomes visible at application
protocol level.
.Sp
For socket \fB\s-1BIO\s0\fRs (e.g. when \fISSL_set_fd()\fR was used), \fIselect()\fR or
\&\fIpoll()\fR on the underlying socket can be used to find out when the
\&\s-1TLS/SSL\s0 I/O function should be retried.
.Sp
Caveat: Any \s-1TLS/SSL\s0 I/O function can lead to either of
\&\fB\s-1SSL_ERROR_WANT_READ\s0\fR and \fB\s-1SSL_ERROR_WANT_WRITE\s0\fR. In particular,
\&\fISSL_read()\fR or \fISSL_peek()\fR may want to write data and \fISSL_write()\fR may want
to read data. This is mainly because \s-1TLS/SSL\s0 handshakes may occur at any
time during the protocol (initiated by either the client or the server);
\&\fISSL_read()\fR, \fISSL_peek()\fR, and \fISSL_write()\fR will handle any pending handshakes.
.Ip "\s-1SSL_ERROR_WANT_CONNECT\s0, \s-1SSL_ERROR_WANT_ACCEPT\s0" 4
.IX Item "SSL_ERROR_WANT_CONNECT, SSL_ERROR_WANT_ACCEPT"
The operation did not complete; the same \s-1TLS/SSL\s0 I/O function should be
called again later. The underlying \s-1BIO\s0 was not connected yet to the peer
and the call would block in \fIconnect()\fR/\fIaccept()\fR. The \s-1SSL\s0 function should be
called again when the connection is established. These messages can only
appear with a \fIBIO_s_connect()\fR or \fIBIO_s_accept()\fR \s-1BIO\s0, respectively.
In order to find out, when the connection has been successfully established,
on many platforms \fIselect()\fR or \fIpoll()\fR for writing on the socket file descriptor
can be used.
.Ip "\s-1SSL_ERROR_WANT_X509_LOOKUP\s0" 4
.IX Item "SSL_ERROR_WANT_X509_LOOKUP"
The operation did not complete because an application callback set by
\&\fISSL_CTX_set_client_cert_cb()\fR has asked to be called again.
The \s-1TLS/SSL\s0 I/O function should be called again later.
Details depend on the application.
.Ip "\s-1SSL_ERROR_SYSCALL\s0" 4
.IX Item "SSL_ERROR_SYSCALL"
Some I/O error occurred. The OpenSSL error queue may contain more
information on the error. If the error queue is empty
(i.e. \fIERR_get_error()\fR returns 0), \fBret\fR can be used to find out more
about the error: If \fBret == 0\fR, an \s-1EOF\s0 was observed that violates
the protocol. If \fBret == \-1\fR, the underlying \fB\s-1BIO\s0\fR reported an
I/O error (for socket I/O on Unix systems, consult \fBerrno\fR for details).
.Ip "\s-1SSL_ERROR_SSL\s0" 4
.IX Item "SSL_ERROR_SSL"
A failure in the \s-1SSL\s0 library occurred, usually a protocol error. The
OpenSSL error queue contains more information on the error.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
ssl(3), openssl_err(3)
.SH "HISTORY"
.IX Header "HISTORY"
\&\fISSL_get_error()\fR was added in SSLeay 0.8.