93 lines
3 KiB
Text
93 lines
3 KiB
Text
=pod
|
|
|
|
=head1 NAME
|
|
|
|
SSL_get_error - obtain result code for TLS/SSL I/O operation
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/ssl.h>
|
|
|
|
int SSL_get_error(SSL *ssl, int ret);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
SSL_get_error() returns a result code (suitable for the C "switch"
|
|
statement) for a preceding call to SSL_connect(), SSL_accept(),
|
|
SSL_read(), or SSL_write() on B<ssl>. The value returned by that
|
|
TLS/SSL I/O function must be passed to SSL_get_error() in parameter
|
|
B<ret>.
|
|
|
|
In addition to B<ssl> and B<ret>, SSL_get_error() inspects the
|
|
current thread's OpenSSL error queue. Thus, SSL_get_error() must be
|
|
used in the same thread that performed the TLS/SSL I/O operation, and no
|
|
other OpenSSL function calls should appear in between. The current
|
|
thread's error queue must be empty before the TLS/SSL I/O operation is
|
|
attempted, or SSL_get_error() will not work reliably.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
The following return values can currently occur:
|
|
|
|
=over 4
|
|
|
|
=item SSL_ERROR_NONE
|
|
|
|
The TLS/SSL I/O operation completed. This result code is returned
|
|
if and only if B<ret E<gt> 0>.
|
|
|
|
=item SSL_ERROR_ZERO_RETURN
|
|
|
|
The TLS/SSL connection has been closed. If the protocol version is SSL 3.0
|
|
or TLS 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 B<SSL_ERROR_ZERO_RETURN>
|
|
does not necessarily indicate that the underlying transport
|
|
has been closed.
|
|
|
|
=item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE
|
|
|
|
The operation did not complete; the same TLS/SSL I/O function should be
|
|
called again later. There will be protocol progress if, by then, the
|
|
underlying B<BIO> has data available for reading (if the result code is
|
|
B<SSL_ERROR_WANT_READ>) or allows writing data (B<SSL_ERROR_WANT_WRITE>).
|
|
For socket B<BIO>s (e.g. when SSL_set_fd() was used) this means that
|
|
select() or poll() on the underlying socket can be used to find out
|
|
when the TLS/SSL I/O function should be retried.
|
|
|
|
Caveat: Any TLS/SSL I/O function can lead to either of
|
|
B<SSL_ERROR_WANT_READ> and B<SSL_ERROR_WANT_WRITE>, i.e. SSL_read()
|
|
may want to write data and SSL_write() may want to read data.
|
|
|
|
=item SSL_ERROR_WANT_X509_LOOKUP
|
|
|
|
The operation did not complete because an application callback set by
|
|
SSL_CTX_set_client_cert_cb() has asked to be called again.
|
|
The TLS/SSL I/O function should be called again later.
|
|
Details depend on the application.
|
|
|
|
=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. ERR_get_error() returns 0), B<ret> can be used to find out more
|
|
about the error: If B<ret == 0>, an EOF was observed that violates
|
|
the protocol. If B<ret == -1>, the underlying B<BIO> reported an
|
|
I/O error (for socket I/O on Unix systems, consult B<errno> for details).
|
|
|
|
=item SSL_ERROR_SSL
|
|
|
|
A failure in the SSL library occurred, usually a protocol error. The
|
|
OpenSSL error queue contains more information on the error.
|
|
|
|
=back
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<ssl(3)|ssl(3)>, L<err(3)|err(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
SSL_get_error() was added in SSLeay 0.8.
|
|
|
|
=cut
|