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4e3973b457
After the recent reworking, not everything matched up, and some comments didn't catch up to the outl-->dlen and inl-->dlen renames that happened during the development of the recent patches. Try to make parameter names consistent across header, implementation, and manual pages. Also remove some trailing whitespace that was inadvertently introduced. Reviewed-by: Matt Caswell <matt@openssl.org> Reviewed-by: Richard Levitte <levitte@openssl.org> (Merged from https://github.com/openssl/openssl/pull/1798)
221 lines
5.8 KiB
Plaintext
221 lines
5.8 KiB
Plaintext
=pod
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=head1 NAME
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BIO_set_callback_ex, BIO_get_callback_ex, BIO_set_callback, BIO_get_callback,
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BIO_set_callback_arg, BIO_get_callback_arg, BIO_debug_callback
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- BIO callback functions
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=head1 SYNOPSIS
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#include <openssl/bio.h>
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typedef long (*BIO_callback_fn_ex)(BIO *b, int oper, const char *argp,
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size_t len, int argi,
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long argl, int ret, size_t *processed);
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typedef long (*BIO_callback_fn)(BIO *b, int oper, const char *argp, int argi,
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long argl, long ret);
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void BIO_set_callback_ex(BIO *b, BIO_callback_fn_ex callback);
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BIO_callback_fn_ex BIO_get_callback_ex(const BIO *b);
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void BIO_set_callback(BIO *b, BIO_callack_fn cb);
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BIO_callack_fn BIO_get_callback(BIO *b);
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void BIO_set_callback_arg(BIO *b, char *arg);
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char *BIO_get_callback_arg(const BIO *b);
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long BIO_debug_callback(BIO *bio, int cmd, const char *argp, int argi,
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long argl, long ret);
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=head1 DESCRIPTION
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BIO_set_callback_ex() and BIO_get_callback_ex() set and retrieve the BIO
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callback. The callback is called during most high level BIO operations. It can
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be used for debugging purposes to trace operations on a BIO or to modify its
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operation.
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BIO_set_callback() and BIO_get_callback() set and retrieve the old format BIO
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callback. New code should not use these functions, but they are retained for
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backwards compatbility. Any callback set via BIO_set_callback_ex() will get
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called in preference to any set by BIO_set_callback().
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BIO_set_callback_arg() and BIO_get_callback_arg() are macros which can be
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used to set and retrieve an argument for use in the callback.
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BIO_debug_callback() is a standard debugging callback which prints
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out information relating to each BIO operation. If the callback
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argument is set it is interpreted as a BIO to send the information
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to, otherwise stderr is used.
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BIO_callback_fn_ex() is the type of the callback function and BIO_callback_fn()
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is the type of the old format callback function. The meaning of each argument
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is described below:
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=over
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=item B<b>
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The BIO the callback is attached to is passed in B<b>.
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=item B<oper>
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B<oper> is set to the operation being performed. For some operations
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the callback is called twice, once before and once after the actual
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operation, the latter case has B<oper> or'ed with BIO_CB_RETURN.
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=item B<len>
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The length of the data requested to be read or written. This is only useful if
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B<oper> is BIO_CB_READ, BIO_CB_WRITE or BIO_CB_GETS.
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=item B<argp> B<argi> B<argl>
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The meaning of the arguments B<argp>, B<argi> and B<argl> depends on
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the value of B<oper>, that is the operation being performed.
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=item B<processed>
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B<processed> is a pointer to a location which will be updated with the amount of
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data that was actually read or written. Only used for BIO_CB_READ, BIO_CB_WRITE,
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BIO_CB_GETS and BIO_CB_PUTS.
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=item B<ret>
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B<ret> is the return value that would be returned to the
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application if no callback were present. The actual value returned
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is the return value of the callback itself. In the case of callbacks
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called before the actual BIO operation 1 is placed in B<ret>, if
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the return value is not positive it will be immediately returned to
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the application and the BIO operation will not be performed.
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=back
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The callback should normally simply return B<ret> when it has
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finished processing, unless it specifically wishes to modify the
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value returned to the application.
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=head1 CALLBACK OPERATIONS
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In the notes below, B<callback> defers to the actual callback
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function that is called.
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=over 4
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=item B<BIO_free(b)>
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callback_ex(b, BIO_CB_FREE, NULL, 0, 0, 0L, 1L, NULL)
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or
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callback(b, BIO_CB_FREE, NULL, 0L, 0L, 1L)
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is called before the free operation.
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=item B<BIO_read_ex(b, data, dlen, readbytes)>
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callback_ex(b, BIO_CB_READ, data, dlen, 0, 0L, 1L, readbytes)
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or
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callback(b, BIO_CB_READ, data, dlen, 0L, 1L)
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is called before the read and
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callback_ex(b, BIO_CB_READ | BIO_CB_RETURN, data, dlen, 0, 0L, retvalue, readbytes)
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or
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callback(b, BIO_CB_READ|BIO_CB_RETURN, data, dlen, 0L, retvalue)
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after.
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=item B<BIO_write(b, data, dlen, written)>
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callback_ex(b, BIO_CB_WRITE, data, dlen, 0, 0L, 1L, written)
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or
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callback(b, BIO_CB_WRITE, datat, dlen, 0L, 1L)
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is called before the write and
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callback_ex(b, BIO_CB_WRITE | BIO_CB_RETURN, data, dlen, 0, 0L, retvalue, written)
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or
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callback(b, BIO_CB_WRITE|BIO_CB_RETURN, data, dlen, 0L, retvalue)
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after.
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=item B<BIO_gets(b, buf, size)>
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callback_ex(b, BIO_CB_GETS, buf, size, 0, 0L, 1, NULL, NULL)
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or
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callback(b, BIO_CB_GETS, buf, size, 0L, 1L)
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is called before the operation and
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callback_ex(b, BIO_CB_GETS | BIO_CB_RETURN, buf, size, 0, 0L, retvalue, readbytes)
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or
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callback(b, BIO_CB_GETS|BIO_CB_RETURN, buf, size, 0L, retvalue)
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after.
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=item B<BIO_puts(b, buf)>
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callback_ex(b, BIO_CB_PUTS, buf, 0, 0, 0L, 1L, NULL);
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or
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callback(b, BIO_CB_PUTS, buf, 0, 0L, 1L)
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is called before the operation and
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callback_ex(b, BIO_CB_PUTS | BIO_CB_RETURN, buf, 0, 0, 0L, retvalue, written)
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or
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callback(b, BIO_CB_WRITE|BIO_CB_RETURN, buf, 0, 0L, retvalue)
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after.
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=item B<BIO_ctrl(BIO *b, int cmd, long larg, void *parg)>
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callback_ex(b, BIO_CB_CTRL, parg, 0, cmd, larg, 1L, NULL)
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or
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callback(b, BIO_CB_CTRL, parg, cmd, larg, 1L)
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is called before the call and
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callback_ex(b, BIO_CB_CTRL | BIO_CB_RETURN, parg, 0, cmd, larg, ret, NULL)
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or
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callback(b, BIO_CB_CTRL|BIO_CB_RETURN, parg, cmd, larg, ret)
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after.
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=back
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=head1 EXAMPLE
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The BIO_debug_callback() function is a good example, its source is
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in crypto/bio/bio_cb.c
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=head1 COPYRIGHT
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Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
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Licensed under the OpenSSL license (the "License"). You may not use
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this file except in compliance with the License. You can obtain a copy
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in the file LICENSE in the source distribution or at
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L<https://www.openssl.org/source/license.html>.
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=cut
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