1=pod 2 3=head1 NAME 4 5BIO_get_new_index, 6BIO_meth_new, BIO_meth_free, BIO_meth_get_read_ex, BIO_meth_set_read_ex, 7BIO_meth_get_write_ex, BIO_meth_set_write_ex, BIO_meth_get_write, 8BIO_meth_set_write, BIO_meth_get_read, BIO_meth_set_read, BIO_meth_get_puts, 9BIO_meth_set_puts, BIO_meth_get_gets, BIO_meth_set_gets, BIO_meth_get_ctrl, 10BIO_meth_set_ctrl, BIO_meth_get_create, BIO_meth_set_create, 11BIO_meth_get_destroy, BIO_meth_set_destroy, BIO_meth_get_callback_ctrl, 12BIO_meth_set_callback_ctrl, BIO_meth_set_sendmmsg, BIO_meth_get_sendmmsg, 13BIO_meth_set_recvmmsg, BIO_meth_get_recvmmsg - Routines to build up BIO methods 14 15=head1 SYNOPSIS 16 17 #include <openssl/bio.h> 18 19 int BIO_get_new_index(void); 20 21 BIO_METHOD *BIO_meth_new(int type, const char *name); 22 23 void BIO_meth_free(BIO_METHOD *biom); 24 25 int BIO_meth_set_write_ex(BIO_METHOD *biom, 26 int (*bwrite)(BIO *, const char *, size_t, size_t *)); 27 int BIO_meth_set_write(BIO_METHOD *biom, 28 int (*write)(BIO *, const char *, int)); 29 30 int BIO_meth_set_read_ex(BIO_METHOD *biom, 31 int (*bread)(BIO *, char *, size_t, size_t *)); 32 int BIO_meth_set_read(BIO_METHOD *biom, int (*read)(BIO *, char *, int)); 33 34 int BIO_meth_set_puts(BIO_METHOD *biom, int (*puts)(BIO *, const char *)); 35 int BIO_meth_set_gets(BIO_METHOD *biom, 36 int (*gets)(BIO *, char *, int)); 37 38 int BIO_meth_set_ctrl(BIO_METHOD *biom, 39 long (*ctrl)(BIO *, int, long, void *)); 40 41 int BIO_meth_set_create(BIO_METHOD *biom, int (*create)(BIO *)); 42 int BIO_meth_set_destroy(BIO_METHOD *biom, int (*destroy)(BIO *)); 43 44 int BIO_meth_set_callback_ctrl(BIO_METHOD *biom, 45 long (*callback_ctrl)(BIO *, int, BIO_info_cb *)); 46 47 int BIO_meth_set_sendmmsg(BIO_METHOD *biom, 48 ossl_ssize_t (*f) (BIO *, BIO_MSG *, size_t, 49 size_t, uint64_t)); 50 int BIO_meth_set_recvmmsg(BIO_METHOD *biom, 51 ossl_ssize_t (*f) (BIO *, BIO_MSG *, size_t, 52 size_t, uint64_t)); 53 54The following functions have been deprecated since OpenSSL 3.5: 55 56 int (*BIO_meth_get_write_ex(const BIO_METHOD *biom))(BIO *, const char *, size_t, 57 size_t *); 58 int (*BIO_meth_get_write(const BIO_METHOD *biom))(BIO *, const char *, int); 59 60 int (*BIO_meth_get_read_ex(const BIO_METHOD *biom))(BIO *, char *, size_t, size_t *); 61 int (*BIO_meth_get_read(const BIO_METHOD *biom))(BIO *, char *, int); 62 63 int (*BIO_meth_get_puts(const BIO_METHOD *biom))(BIO *, const char *); 64 int (*BIO_meth_get_gets(const BIO_METHOD *biom))(BIO *, char *, int); 65 66 long (*BIO_meth_get_ctrl(const BIO_METHOD *biom))(BIO *, int, long, void *); 67 68 int (*BIO_meth_get_create(const BIO_METHOD *bion))(BIO *); 69 int (*BIO_meth_get_destroy(const BIO_METHOD *biom))(BIO *); 70 71 long (*BIO_meth_get_callback_ctrl(const BIO_METHOD *biom))(BIO *, int, BIO_info_cb *); 72 73 ossl_ssize_t (*BIO_meth_get_sendmmsg(const BIO_METHOD *biom))(BIO *, 74 BIO_MSG *, 75 size_t, 76 size_t, 77 uint64_t); 78 ossl_ssize_t (*BIO_meth_get_recvmmsg(const BIO_METHOD *biom))(BIO *, 79 BIO_MSG *, 80 size_t, 81 size_t, 82 uint64_t); 83 84=head1 DESCRIPTION 85 86The B<BIO_METHOD> type is a structure used for the implementation of new BIO 87types. It provides a set of functions used by OpenSSL for the implementation 88of the various BIO capabilities. See the L<bio(7)> page for more information. 89 90BIO_meth_new() creates a new B<BIO_METHOD> structure that contains a type 91identifier I<type> and a string that represents its B<name>. 92B<type> can be set to either B<BIO_TYPE_NONE> or via BIO_get_new_index() if 93a unique type is required for searching (See L<BIO_find_type(3)>) 94 95Note that BIO_get_new_index() can only be used 127 times before it returns an 96error. 97 98The set of 99standard OpenSSL provided BIO types is provided in F<< <openssl/bio.h> >>. 100Some examples include B<BIO_TYPE_BUFFER> and B<BIO_TYPE_CIPHER>. Filter BIOs 101should have a type which have the "filter" bit set (B<BIO_TYPE_FILTER>). 102Source/sink BIOs should have the "source/sink" bit set (B<BIO_TYPE_SOURCE_SINK>). 103File descriptor based BIOs (e.g. socket, fd, connect, accept etc) should 104additionally have the "descriptor" bit set (B<BIO_TYPE_DESCRIPTOR>). See the 105L<BIO_find_type(3)> page for more information. 106 107BIO_meth_free() destroys a B<BIO_METHOD> structure and frees up any memory 108associated with it. If the argument is NULL, nothing is done. 109 110BIO_meth_get_write_ex() and BIO_meth_set_write_ex() get and set the function 111used for writing arbitrary length data to the BIO respectively. This function 112will be called in response to the application calling BIO_write_ex() or 113BIO_write(). The parameters for the function have the same meaning as for 114BIO_write_ex(). Older code may call BIO_meth_get_write() and 115BIO_meth_set_write() instead. Applications should not call both 116BIO_meth_set_write_ex() and BIO_meth_set_write() or call BIO_meth_get_write() 117when the function was set with BIO_meth_set_write_ex(). 118 119BIO_meth_get_read_ex() and BIO_meth_set_read_ex() get and set the function used 120for reading arbitrary length data from the BIO respectively. This function will 121be called in response to the application calling BIO_read_ex() or BIO_read(). 122The parameters for the function have the same meaning as for BIO_read_ex(). 123Older code may call BIO_meth_get_read() and BIO_meth_set_read() instead. 124Applications should not call both BIO_meth_set_read_ex() and BIO_meth_set_read() 125or call BIO_meth_get_read() when the function was set with 126BIO_meth_set_read_ex(). 127 128BIO_meth_get_puts() and BIO_meth_set_puts() get and set the function used for 129writing a NULL terminated string to the BIO respectively. This function will be 130called in response to the application calling BIO_puts(). The parameters for 131the function have the same meaning as for BIO_puts(). 132 133BIO_meth_get_gets() and BIO_meth_set_gets() get and set the function typically 134used for reading a line of data from the BIO respectively (see the L<BIO_gets(3)> 135page for more information). This function will be called in response to the 136application calling BIO_gets(). The parameters for the function have the same 137meaning as for BIO_gets(). 138 139BIO_meth_get_ctrl() and BIO_meth_set_ctrl() get and set the function used for 140processing ctrl messages in the BIO respectively. See the L<BIO_ctrl(3)> page for 141more information. This function will be called in response to the application 142calling BIO_ctrl(). The parameters for the function have the same meaning as for 143BIO_ctrl(). 144 145BIO_meth_get_create() and BIO_meth_set_create() get and set the function used 146for creating a new instance of the BIO respectively. This function will be 147called in response to the application calling BIO_new() and passing 148in a pointer to the current BIO_METHOD. The BIO_new() function will allocate the 149memory for the new BIO, and a pointer to this newly allocated structure will 150be passed as a parameter to the function. If a create function is set, 151BIO_new() will not mark the BIO as initialised on allocation. 152L<BIO_set_init(3)> must then be called either by the create function, or later, 153by a BIO ctrl function, once BIO initialisation is complete. 154 155BIO_meth_get_destroy() and BIO_meth_set_destroy() get and set the function used 156for destroying an instance of a BIO respectively. This function will be 157called in response to the application calling BIO_free(). A pointer to the BIO 158to be destroyed is passed as a parameter. The destroy function should be used 159for BIO specific clean up. The memory for the BIO itself should not be freed by 160this function. 161 162BIO_meth_get_callback_ctrl() and BIO_meth_set_callback_ctrl() get and set the 163function used for processing callback ctrl messages in the BIO respectively. See 164the L<BIO_callback_ctrl(3)> page for more information. This function will be called 165in response to the application calling BIO_callback_ctrl(). The parameters for 166the function have the same meaning as for BIO_callback_ctrl(). 167 168BIO_meth_get_sendmmsg(), BIO_meth_set_sendmmsg(), BIO_meth_get_recvmmsg() and 169BIO_meth_set_recvmmsg() get and set the functions used for handling 170BIO_sendmmsg() and BIO_recvmmsg() calls respectively. See L<BIO_sendmmsg(3)> for 171more information. 172 173=head1 RETURN VALUES 174 175BIO_get_new_index() returns the new BIO type value or -1 if an error occurred. 176 177BIO_meth_new(int type, const char *name) returns a valid B<BIO_METHOD> or NULL 178if an error occurred. 179 180The B<BIO_meth_set> functions return 1 on success or 0 on error. 181 182The B<BIO_meth_get> functions return the corresponding function pointers. 183 184=head1 BUGS 185 186It is not safe to use C<BIO_meth_get_> functions to reuse the B<BIO> 187implementation of B<BIO>s implemented by OpenSSL itself with 188application-implemented B<BIO>s. Instead either the applications ought to 189implement these functions themselves or they should implement a filter BIO. 190 191For more details please see L<https://github.com/openssl/openssl/issues/26047>. 192 193=head1 SEE ALSO 194 195L<bio(7)>, L<BIO_find_type(3)>, L<BIO_ctrl(3)>, L<BIO_read_ex(3)>, L<BIO_new(3)> 196 197=head1 HISTORY 198 199The functions BIO_meth_get_sendmmsg(), BIO_meth_set_sendmmsg(), 200BIO_meth_get_recvmmsg() and BIO_meth_set_recvmmsg() were added in OpenSSL 3.2. 201 202All the other functions described here were added in OpenSSL 1.1.0. 203 204The functions BIO_meth_get_read_ex(), BIO_meth_get_write_ex(), 205BIO_meth_get_write(), BIO_meth_get_read(), BIO_meth_get_puts(), 206BIO_meth_get_gets(), BIO_meth_get_ctrl(), BIO_meth_get_create(), 207BIO_meth_get_destroy(), BIO_meth_get_callback_ctrl(), 208BIO_meth_get_sendmmsg() and BIO_meth_get_recvmmsg() are deprecated since 209OpenSSL 3.5. 210 211=head1 COPYRIGHT 212 213Copyright 2016-2024 The OpenSSL Project Authors. All Rights Reserved. 214 215Licensed under the Apache License 2.0 (the "License"). You may not use 216this file except in compliance with the License. You can obtain a copy 217in the file LICENSE in the source distribution or at 218L<https://www.openssl.org/source/license.html>. 219 220=cut 221
