1=pod
2
3=head1 NAME
4
5SSL_get_error - obtain result code for TLS/SSL I/O operation
6
7=head1 SYNOPSIS
8
9 #include <openssl/ssl.h>
10
11 int SSL_get_error(SSL *ssl, int ret);
12
13=head1 DESCRIPTION
14
15SSL_get_error() returns a result code (suitable for the C "switch"
16statement) for a preceding call to SSL_connect(), SSL_accept(),
17SSL_read(), SSL_peek(), or SSL_write() on B<ssl>. The value returned by
18that TLS/SSL I/O function must be passed to SSL_get_error() in parameter
19B<ret>.
20
21In addition to B<ssl> and B<ret>, SSL_get_error() inspects the
22current thread's OpenSSL error queue. Thus, SSL_get_error() must be
23used in the same thread that performed the TLS/SSL I/O operation, and no
24other OpenSSL function calls should appear in between. The current
25thread's error queue must be empty before the TLS/SSL I/O operation is
26attempted, or SSL_get_error() will not work reliably.
27
28=head1 RETURN VALUES
29
30The following return values can currently occur:
31
32=over 4
33
34=item SSL_ERROR_NONE
35
36The TLS/SSL I/O operation completed. This result code is returned
37if and only if B<ret E<gt> 0>.
38
39=item SSL_ERROR_ZERO_RETURN
40
41The TLS/SSL connection has been closed. If the protocol version is SSL 3.0
42or TLS 1.0, this result code is returned only if a closure
43alert has occurred in the protocol, i.e. if the connection has been
44closed cleanly. Note that in this case B<SSL_ERROR_ZERO_RETURN>
45does not necessarily indicate that the underlying transport
46has been closed.
47
48=item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE
49
50The operation did not complete; the same TLS/SSL I/O function should be
51called again later. If, by then, the underlying B<BIO> has data
52available for reading (if the result code is B<SSL_ERROR_WANT_READ>)
53or allows writing data (B<SSL_ERROR_WANT_WRITE>), then some TLS/SSL
54protocol progress will take place, i.e. at least part of an TLS/SSL
55record will be read or written. Note that the retry may again lead to
56a B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE> condition.
57There is no fixed upper limit for the number of iterations that
58may be necessary until progress becomes visible at application
59protocol level.
60
61For socket B<BIO>s (e.g. when SSL_set_fd() was used), select() or
62poll() on the underlying socket can be used to find out when the
63TLS/SSL I/O function should be retried.
64
65Caveat: Any TLS/SSL I/O function can lead to either of
66B<SSL_ERROR_WANT_READ> and B<SSL_ERROR_WANT_WRITE>. In particular,
67SSL_read() or SSL_peek() may want to write data and SSL_write() may want
68to read data. This is mainly because TLS/SSL handshakes may occur at any
69time during the protocol (initiated by either the client or the server);
70SSL_read(), SSL_peek(), and SSL_write() will handle any pending handshakes.
71
| 1=pod
2
3=head1 NAME
4
5SSL_get_error - obtain result code for TLS/SSL I/O operation
6
7=head1 SYNOPSIS
8
9 #include <openssl/ssl.h>
10
11 int SSL_get_error(SSL *ssl, int ret);
12
13=head1 DESCRIPTION
14
15SSL_get_error() returns a result code (suitable for the C "switch"
16statement) for a preceding call to SSL_connect(), SSL_accept(),
17SSL_read(), SSL_peek(), or SSL_write() on B<ssl>. The value returned by
18that TLS/SSL I/O function must be passed to SSL_get_error() in parameter
19B<ret>.
20
21In addition to B<ssl> and B<ret>, SSL_get_error() inspects the
22current thread's OpenSSL error queue. Thus, SSL_get_error() must be
23used in the same thread that performed the TLS/SSL I/O operation, and no
24other OpenSSL function calls should appear in between. The current
25thread's error queue must be empty before the TLS/SSL I/O operation is
26attempted, or SSL_get_error() will not work reliably.
27
28=head1 RETURN VALUES
29
30The following return values can currently occur:
31
32=over 4
33
34=item SSL_ERROR_NONE
35
36The TLS/SSL I/O operation completed. This result code is returned
37if and only if B<ret E<gt> 0>.
38
39=item SSL_ERROR_ZERO_RETURN
40
41The TLS/SSL connection has been closed. If the protocol version is SSL 3.0
42or TLS 1.0, this result code is returned only if a closure
43alert has occurred in the protocol, i.e. if the connection has been
44closed cleanly. Note that in this case B<SSL_ERROR_ZERO_RETURN>
45does not necessarily indicate that the underlying transport
46has been closed.
47
48=item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE
49
50The operation did not complete; the same TLS/SSL I/O function should be
51called again later. If, by then, the underlying B<BIO> has data
52available for reading (if the result code is B<SSL_ERROR_WANT_READ>)
53or allows writing data (B<SSL_ERROR_WANT_WRITE>), then some TLS/SSL
54protocol progress will take place, i.e. at least part of an TLS/SSL
55record will be read or written. Note that the retry may again lead to
56a B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE> condition.
57There is no fixed upper limit for the number of iterations that
58may be necessary until progress becomes visible at application
59protocol level.
60
61For socket B<BIO>s (e.g. when SSL_set_fd() was used), select() or
62poll() on the underlying socket can be used to find out when the
63TLS/SSL I/O function should be retried.
64
65Caveat: Any TLS/SSL I/O function can lead to either of
66B<SSL_ERROR_WANT_READ> and B<SSL_ERROR_WANT_WRITE>. In particular,
67SSL_read() or SSL_peek() may want to write data and SSL_write() may want
68to read data. This is mainly because TLS/SSL handshakes may occur at any
69time during the protocol (initiated by either the client or the server);
70SSL_read(), SSL_peek(), and SSL_write() will handle any pending handshakes.
71
|
79In order to find out, when the connection has been successfully established,
80on many platforms select() or poll() for writing on the socket file descriptor
81can be used.
82
83=item SSL_ERROR_WANT_X509_LOOKUP
84
85The operation did not complete because an application callback set by
86SSL_CTX_set_client_cert_cb() has asked to be called again.
87The TLS/SSL I/O function should be called again later.
88Details depend on the application.
89
90=item SSL_ERROR_SYSCALL
91
92Some I/O error occurred. The OpenSSL error queue may contain more
93information on the error. If the error queue is empty
94(i.e. ERR_get_error() returns 0), B<ret> can be used to find out more
95about the error: If B<ret == 0>, an EOF was observed that violates
96the protocol. If B<ret == -1>, the underlying B<BIO> reported an
97I/O error (for socket I/O on Unix systems, consult B<errno> for details).
98
99=item SSL_ERROR_SSL
100
101A failure in the SSL library occurred, usually a protocol error. The
102OpenSSL error queue contains more information on the error.
103
104=back
105
106=head1 SEE ALSO
107
108L<ssl(3)|ssl(3)>, L<err(3)|err(3)>
109
110=head1 HISTORY
111
112SSL_get_error() was added in SSLeay 0.8.
113
114=cut
| 79In order to find out, when the connection has been successfully established,
80on many platforms select() or poll() for writing on the socket file descriptor
81can be used.
82
83=item SSL_ERROR_WANT_X509_LOOKUP
84
85The operation did not complete because an application callback set by
86SSL_CTX_set_client_cert_cb() has asked to be called again.
87The TLS/SSL I/O function should be called again later.
88Details depend on the application.
89
90=item SSL_ERROR_SYSCALL
91
92Some I/O error occurred. The OpenSSL error queue may contain more
93information on the error. If the error queue is empty
94(i.e. ERR_get_error() returns 0), B<ret> can be used to find out more
95about the error: If B<ret == 0>, an EOF was observed that violates
96the protocol. If B<ret == -1>, the underlying B<BIO> reported an
97I/O error (for socket I/O on Unix systems, consult B<errno> for details).
98
99=item SSL_ERROR_SSL
100
101A failure in the SSL library occurred, usually a protocol error. The
102OpenSSL error queue contains more information on the error.
103
104=back
105
106=head1 SEE ALSO
107
108L<ssl(3)|ssl(3)>, L<err(3)|err(3)>
109
110=head1 HISTORY
111
112SSL_get_error() was added in SSLeay 0.8.
113
114=cut
|