doc/man3/SSL_get_error.pod - third_party/openssl - Git at Google

 =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(const 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_do_handshake(),
 SSL_read_ex(), SSL_read(), SSL_peek_ex(), SSL_peek(), SSL_shutdown(),
 SSL_write_ex() 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 NOTES

 Some TLS implementations do not send a close_notify alert on shutdown.

 On an unexpected EOF, versions before OpenSSL 3.0 returned
 B<SSL_ERROR_SYSCALL>, nothing was added to the error stack, and errno was 0.
 Since OpenSSL 3.0 the returned error is B<SSL_ERROR_SSL> with a meaningful
 error on the error stack.

 =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 peer has closed the connection for writing by sending the
 close_notify alert.
 No more data can be read.
 Note that B<SSL_ERROR_ZERO_RETURN> does not necessarily
 indicate that the underlying transport has been closed.

 This error can also appear when the option B<SSL_OP_IGNORE_UNEXPECTED_EOF>
 is set. See L<SSL_CTX_set_options(3)> for more details.

 =item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE

 The operation did not complete and can be retried later.

 B<SSL_ERROR_WANT_READ> is returned when the last operation was a read
 operation from a nonblocking B<BIO>.
 It means that not enough data was available at this time to complete the
 operation.
 If at a later time the underlying B<BIO> has data available for reading the same
 function can be called again.

 SSL_read() and SSL_read_ex() can also set B<SSL_ERROR_WANT_READ> when there is
 still unprocessed data available at either the B<SSL> or the B<BIO> layer, even
 for a blocking B<BIO>.
 See L<SSL_read(3)> for more information.

 B<SSL_ERROR_WANT_WRITE> is returned when the last operation was a write
 to a nonblocking B<BIO> and it was unable to sent all data to the B<BIO>.
 When the B<BIO> is writable again, the same function can be called again.

 Note that the retry may again lead to an B<SSL_ERROR_WANT_READ> or
 B<SSL_ERROR_WANT_WRITE> condition.
 There is no fixed upper limit for the number of iterations that
 may be necessary until progress becomes visible at application
 protocol level.

 It is safe to call SSL_read() or SSL_read_ex() when more data is available
 even when the call that set this error was an SSL_write() or SSL_write_ex().
 However, if the call was an SSL_write() or SSL_write_ex(), it should be called
 again to continue sending the application data. If you get B<SSL_ERROR_WANT_WRITE>
 from SSL_write() or SSL_write_ex() then you should not do any other operation
 that could trigger B<IO> other than to repeat the previous SSL_write() call.

 For socket B<BIO>s (e.g. when SSL_set_fd() was used), 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>.
 In particular,
 SSL_read_ex(), SSL_read(), SSL_peek_ex(), or SSL_peek() may want to write data
 and SSL_write() or SSL_write_ex() may want to read data.
 This is mainly because
 TLS/SSL handshakes may occur at any time during the protocol (initiated by
 either the client or the server); SSL_read_ex(), SSL_read(), SSL_peek_ex(),
 SSL_peek(), SSL_write_ex(), and SSL_write() will handle any pending handshakes.

 =item SSL_ERROR_WANT_CONNECT, SSL_ERROR_WANT_ACCEPT

 The operation did not complete; the same TLS/SSL I/O function should be
 called again later. The underlying BIO was not connected yet to the peer
 and the call would block in connect()/accept(). The SSL function should be
 called again when the connection is established. These messages can only
 appear with a BIO_s_connect() or BIO_s_accept() BIO, respectively.
 In order to find out, when the connection has been successfully established,
 on many platforms select() or poll() for writing on the socket file descriptor
 can be used.

 =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_WANT_ASYNC

 The operation did not complete because an asynchronous engine is still
 processing data. This will only occur if the mode has been set to SSL_MODE_ASYNC
 using L<SSL_CTX_set_mode(3)> or L<SSL_set_mode(3)> and an asynchronous capable
 engine is being used. An application can determine whether the engine has
 completed its processing using select() or poll() on the asynchronous wait file
 descriptor. This file descriptor is available by calling
 L<SSL_get_all_async_fds(3)> or L<SSL_get_changed_async_fds(3)>. The TLS/SSL I/O
 function should be called again later. The function B<must> be called from the
 same thread that the original call was made from.

 =item SSL_ERROR_WANT_ASYNC_JOB

 The asynchronous job could not be started because there were no async jobs
 available in the pool (see ASYNC_init_thread(3)). This will only occur if the
 mode has been set to SSL_MODE_ASYNC using L<SSL_CTX_set_mode(3)> or
 L<SSL_set_mode(3)> and a maximum limit has been set on the async job pool
 through a call to L<ASYNC_init_thread(3)>. The application should retry the
 operation after a currently executing asynchronous operation for the current
 thread has completed.

 =item SSL_ERROR_WANT_CLIENT_HELLO_CB

 The operation did not complete because an application callback set by
 SSL_CTX_set_client_hello_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 non-recoverable, fatal I/O error occurred. The OpenSSL error queue may
 contain more information on the error. For socket I/O on Unix systems, consult
 B<errno> for details. If this error occurs then no further I/O operations should
 be performed on the connection and SSL_shutdown() must not be called.

 This value can also be returned for other errors, check the error queue for
 details.

 =item SSL_ERROR_SSL

 A non-recoverable, fatal error in the SSL library occurred, usually a protocol
 error.  The OpenSSL error queue contains more information on the error. If this
 error occurs then no further I/O operations should be performed on the
 connection and SSL_shutdown() must not be called.

 =back

 =head1 SEE ALSO

 L<ssl(7)>

 =head1 HISTORY

 The SSL_ERROR_WANT_ASYNC error code was added in OpenSSL 1.1.0.
 The SSL_ERROR_WANT_CLIENT_HELLO_CB error code was added in OpenSSL 1.1.1.

 =head1 COPYRIGHT

 Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.

 Licensed under the Apache License 2.0 (the "License").  You may not use
 this file except in compliance with the License.  You can obtain a copy
 in the file LICENSE in the source distribution or at
 L<https://www.openssl.org/source/license.html>.

 =cut
	=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(const 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_do_handshake(),
	SSL_read_ex(), SSL_read(), SSL_peek_ex(), SSL_peek(), SSL_shutdown(),
	SSL_write_ex() 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 NOTES

	Some TLS implementations do not send a close_notify alert on shutdown.

	On an unexpected EOF, versions before OpenSSL 3.0 returned
	B<SSL_ERROR_SYSCALL>, nothing was added to the error stack, and errno was 0.
	Since OpenSSL 3.0 the returned error is B<SSL_ERROR_SSL> with a meaningful
	error on the error stack.

	=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 peer has closed the connection for writing by sending the
	close_notify alert.
	No more data can be read.
	Note that B<SSL_ERROR_ZERO_RETURN> does not necessarily
	indicate that the underlying transport has been closed.

	This error can also appear when the option B<SSL_OP_IGNORE_UNEXPECTED_EOF>
	is set. See L<SSL_CTX_set_options(3)> for more details.

	=item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE

	The operation did not complete and can be retried later.

	B<SSL_ERROR_WANT_READ> is returned when the last operation was a read
	operation from a nonblocking B<BIO>.
	It means that not enough data was available at this time to complete the
	operation.
	If at a later time the underlying B<BIO> has data available for reading the same
	function can be called again.

	SSL_read() and SSL_read_ex() can also set B<SSL_ERROR_WANT_READ> when there is
	still unprocessed data available at either the B<SSL> or the B<BIO> layer, even
	for a blocking B<BIO>.
	See L<SSL_read(3)> for more information.

	B<SSL_ERROR_WANT_WRITE> is returned when the last operation was a write
	to a nonblocking B<BIO> and it was unable to sent all data to the B<BIO>.
	When the B<BIO> is writable again, the same function can be called again.

	Note that the retry may again lead to an B<SSL_ERROR_WANT_READ> or
	B<SSL_ERROR_WANT_WRITE> condition.
	There is no fixed upper limit for the number of iterations that
	may be necessary until progress becomes visible at application
	protocol level.

	It is safe to call SSL_read() or SSL_read_ex() when more data is available
	even when the call that set this error was an SSL_write() or SSL_write_ex().
	However, if the call was an SSL_write() or SSL_write_ex(), it should be called
	again to continue sending the application data. If you get B<SSL_ERROR_WANT_WRITE>
	from SSL_write() or SSL_write_ex() then you should not do any other operation
	that could trigger B<IO> other than to repeat the previous SSL_write() call.

	For socket B<BIO>s (e.g. when SSL_set_fd() was used), 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>.
	In particular,
	SSL_read_ex(), SSL_read(), SSL_peek_ex(), or SSL_peek() may want to write data
	and SSL_write() or SSL_write_ex() may want to read data.
	This is mainly because
	TLS/SSL handshakes may occur at any time during the protocol (initiated by
	either the client or the server); SSL_read_ex(), SSL_read(), SSL_peek_ex(),
	SSL_peek(), SSL_write_ex(), and SSL_write() will handle any pending handshakes.

	=item SSL_ERROR_WANT_CONNECT, SSL_ERROR_WANT_ACCEPT

	The operation did not complete; the same TLS/SSL I/O function should be
	called again later. The underlying BIO was not connected yet to the peer
	and the call would block in connect()/accept(). The SSL function should be
	called again when the connection is established. These messages can only
	appear with a BIO_s_connect() or BIO_s_accept() BIO, respectively.
	In order to find out, when the connection has been successfully established,
	on many platforms select() or poll() for writing on the socket file descriptor
	can be used.

	=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_WANT_ASYNC

	The operation did not complete because an asynchronous engine is still
	processing data. This will only occur if the mode has been set to SSL_MODE_ASYNC
	using L<SSL_CTX_set_mode(3)> or L<SSL_set_mode(3)> and an asynchronous capable
	engine is being used. An application can determine whether the engine has
	completed its processing using select() or poll() on the asynchronous wait file
	descriptor. This file descriptor is available by calling
	L<SSL_get_all_async_fds(3)> or L<SSL_get_changed_async_fds(3)>. The TLS/SSL I/O
	function should be called again later. The function B<must> be called from the
	same thread that the original call was made from.

	=item SSL_ERROR_WANT_ASYNC_JOB

	The asynchronous job could not be started because there were no async jobs
	available in the pool (see ASYNC_init_thread(3)). This will only occur if the
	mode has been set to SSL_MODE_ASYNC using L<SSL_CTX_set_mode(3)> or
	L<SSL_set_mode(3)> and a maximum limit has been set on the async job pool
	through a call to L<ASYNC_init_thread(3)>. The application should retry the
	operation after a currently executing asynchronous operation for the current
	thread has completed.

	=item SSL_ERROR_WANT_CLIENT_HELLO_CB

	The operation did not complete because an application callback set by
	SSL_CTX_set_client_hello_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 non-recoverable, fatal I/O error occurred. The OpenSSL error queue may
	contain more information on the error. For socket I/O on Unix systems, consult
	B<errno> for details. If this error occurs then no further I/O operations should
	be performed on the connection and SSL_shutdown() must not be called.

	This value can also be returned for other errors, check the error queue for
	details.

	=item SSL_ERROR_SSL

	A non-recoverable, fatal error in the SSL library occurred, usually a protocol
	error. The OpenSSL error queue contains more information on the error. If this
	error occurs then no further I/O operations should be performed on the
	connection and SSL_shutdown() must not be called.

	=back

	=head1 SEE ALSO

	L<ssl(7)>

	=head1 HISTORY

	The SSL_ERROR_WANT_ASYNC error code was added in OpenSSL 1.1.0.
	The SSL_ERROR_WANT_CLIENT_HELLO_CB error code was added in OpenSSL 1.1.1.

	=head1 COPYRIGHT

	Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.

	Licensed under the Apache License 2.0 (the "License"). You may not use
	this file except in compliance with the License. You can obtain a copy
	in the file LICENSE in the source distribution or at
	L<https://www.openssl.org/source/license.html>.

	=cut