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92 lines
2.9 KiB
Plaintext
92 lines
2.9 KiB
Plaintext
=pod
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=head1 NAME
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SSL_get_error - obtain result code for SSL I/O operation
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=head1 SYNOPSIS
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#include <openssl/ssl.h>
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int SSL_get_error(SSL *ssl, int ret);
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=head1 DESCRIPTION
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SSL_get_error() returns a result code (suitable for the C "switch"
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statement) for a preceding call to SSL_connect(), SSL_accept(),
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SSL_read(), or SSL_write() on B<ssl>. The value returned by that
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SSL I/O function must be passed to SSL_get_error() in parameter
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B<ret>.
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In addition to B<ssl> and B<ret>, SSL_get_error() inspects the
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current thread's OpenSSL error queue. Thus, SSL_get_error() must be
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used in the same thread that performed the SSL I/O operation, and no
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other OpenSSL function calls should appear inbetween. The current
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thread's error queue must be empty before the SSL I/O operation is
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attempted, or SSL_get_error() will not work reliably.
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=head1 RETURN VALUES
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The following return values can currently occur:
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=over 4
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=item SSL_ERROR_NONE
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The SSL I/O operation completed. This result code is returned
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if and only if B<ret > 0>.
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=item SSL_ERROR_ZERO_RETURN
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The SSL connection has been closed. If the protocol version is SSL 3.0
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or TLS 1.0, this result code is returned only if a closure
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alerts has occured in the protocol, i.e. if the connection has been
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closed cleanly.
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=item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE
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The operation did not complete; the same SSL I/O function should be
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called again later. There will be protocol progress if, by then, the
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underlying B<BIO> has data available for reading (if the result code is
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B<SSL_ERROR_WANT_READ>) or allows writing data (B<SSL_ERROR_WANT_WRITE>).
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For socket B<BIO>s (e.g. when SSL_set_fd() was used) this means that
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select() or poll() on the underlying socket can be used to find out
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when the SSL I/O function should be retried.
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Caveat: Any SSL I/O function can lead to either of
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B<SSL_ERROR_WANT_READ> and B<SSL_ERROR_WANT_WRITE>, i.e. SSL_read()
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may want to write data and SSL_write() may want to read data.
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=item SSL_ERROR_WANT_X509_LOOKUP
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The operation did not complete because an application callback set by
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SSL_CTX_set_client_cert_cb() has asked to be called again.
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The SSL I/O function should be called again later.
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Details depend on the application.
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=item SSL_ERROR_SYSCALL
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Some I/O error occurred. The OpenSSL error queue may contain more
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information on the error. If the error queue is empty
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(i.e. ERR_get_error() returns 0), B<ret> can be used to find out more
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about the error: If B<ret == 0>, an EOF was observed that violates
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the protocol. If B<ret == -1>, the underlying B<BIO> reported an
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I/O error (for socket I/O on Unix systems, consult B<errno> for details).
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=item SSL_ERROR_SSL
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A failure in the SSL library occured, usually a protocol error. The
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OpenSSL error queue contains more information on the error.
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=back
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=head1 SEE ALSO
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L<ssl(3)|ssl(3)>, L<err(3)|err(3)>
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=head1 HISTORY
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SSL_get_error() was added in SSLeay 0.8.
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=cut
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