1=pod 2 3=head1 NAME 4 5OSSL_STORE_CTX, OSSL_STORE_post_process_info_fn, 6OSSL_STORE_open, OSSL_STORE_open_ex, 7OSSL_STORE_ctrl, OSSL_STORE_load, OSSL_STORE_eof, 8OSSL_STORE_error, OSSL_STORE_close 9- Types and functions to read objects from a URI 10 11=head1 SYNOPSIS 12 13 #include <openssl/store.h> 14 15 typedef struct ossl_store_ctx_st OSSL_STORE_CTX; 16 17 typedef OSSL_STORE_INFO *(*OSSL_STORE_post_process_info_fn)(OSSL_STORE_INFO *, 18 void *); 19 20 OSSL_STORE_CTX *OSSL_STORE_open(const char *uri, const UI_METHOD *ui_method, 21 void *ui_data, 22 OSSL_STORE_post_process_info_fn post_process, 23 void *post_process_data); 24 OSSL_STORE_CTX * 25 OSSL_STORE_open_ex(const char *uri, OSSL_LIB_CTX *libctx, const char *propq, 26 const UI_METHOD *ui_method, void *ui_data, 27 const OSSL_PARAM params[], 28 OSSL_STORE_post_process_info_fn post_process, 29 void *post_process_data); 30 31 OSSL_STORE_INFO *OSSL_STORE_load(OSSL_STORE_CTX *ctx); 32 int OSSL_STORE_eof(OSSL_STORE_CTX *ctx); 33 int OSSL_STORE_error(OSSL_STORE_CTX *ctx); 34 int OSSL_STORE_close(OSSL_STORE_CTX *ctx); 35 36The following function has been deprecated since OpenSSL 3.0, and can be 37hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value, 38see L<openssl_user_macros(7)>: 39 40 int OSSL_STORE_ctrl(OSSL_STORE_CTX *ctx, int cmd, ... /* args */); 41 42=head1 DESCRIPTION 43 44These functions help the application to fetch supported objects (see 45L<OSSL_STORE_INFO(3)/SUPPORTED OBJECTS> for information on which those are) 46from a given URI. 47The general method to do so is to "open" the URI using OSSL_STORE_open(), 48read each available and supported object using OSSL_STORE_load() as long as 49OSSL_STORE_eof() hasn't been reached, and finish it off with OSSL_STORE_close(). 50 51The retrieved information is stored in a B<OSSL_STORE_INFO>, which is further 52described in L<OSSL_STORE_INFO(3)>. 53 54=head2 Types 55 56B<OSSL_STORE_CTX> is a context variable that holds all the internal 57information for OSSL_STORE_open(), OSSL_STORE_open_ex(), 58OSSL_STORE_load(), OSSL_STORE_eof() and OSSL_STORE_close() to work 59together. 60 61=head2 Functions 62 63OSSL_STORE_open_ex() takes a uri or path I<uri>, password UI method 64I<ui_method> with associated data I<ui_data>, and post processing 65callback I<post_process> with associated data I<post_process_data>, 66a library context I<libctx> with an associated property query I<propq>, 67and opens a channel to the data located at the URI and returns a 68B<OSSL_STORE_CTX> with all necessary internal information. 69The given I<ui_method> and I<ui_data> will be reused by all 70functions that use B<OSSL_STORE_CTX> when interaction is needed, 71for instance to provide a password. 72The auxiliary L<OSSL_PARAM(3)> parameters in I<params> can be set to further 73modify the store operation. 74The given I<post_process> and I<post_process_data> will be reused by 75OSSL_STORE_load() to manipulate or drop the value to be returned. 76The I<post_process> function drops values by returning NULL, which 77will cause OSSL_STORE_load() to start its process over with loading 78the next object, until I<post_process> returns something other than 79NULL, or the end of data is reached as indicated by OSSL_STORE_eof(). 80 81OSSL_STORE_open() is similar to OSSL_STORE_open_ex() but uses NULL for 82the I<params>, the library context I<libctx> and property query I<propq>. 83 84OSSL_STORE_ctrl() takes a B<OSSL_STORE_CTX>, and command number I<cmd> and 85more arguments not specified here. 86The available loader specific command numbers and arguments they each 87take depends on the loader that's used and is documented together with 88that loader. 89 90There are also global controls available: 91 92=over 4 93 94=item B<OSSL_STORE_C_USE_SECMEM> 95 96Controls if the loader should attempt to use secure memory for any 97allocated B<OSSL_STORE_INFO> and its contents. 98This control expects one argument, a pointer to an I<int> that is expected to 99have the value 1 (yes) or 0 (no). 100Any other value is an error. 101 102=back 103 104OSSL_STORE_load() takes a B<OSSL_STORE_CTX> and tries to load the next 105available object and return it wrapped with B<OSSL_STORE_INFO>. 106 107OSSL_STORE_eof() takes a B<OSSL_STORE_CTX> and checks if we've reached the end 108of data. 109 110OSSL_STORE_error() takes a B<OSSL_STORE_CTX> and checks if an error occurred in 111the last OSSL_STORE_load() call. 112Note that it may still be meaningful to try and load more objects, unless 113OSSL_STORE_eof() shows that the end of data has been reached. 114 115OSSL_STORE_close() takes a B<OSSL_STORE_CTX>, closes the channel that was opened 116by OSSL_STORE_open() and frees all other information that was stored in the 117B<OSSL_STORE_CTX>, as well as the B<OSSL_STORE_CTX> itself. 118If I<ctx> is NULL it does nothing. 119 120=head1 NOTES 121 122A string without a scheme prefix (that is, a non-URI string) is 123implicitly interpreted as using the F<file:> scheme. 124 125There are some tools that can be used together with 126OSSL_STORE_open() to determine if any failure is caused by an unparsable 127URI, or if it's a different error (such as memory allocation 128failures); if the URI was parsable but the scheme unregistered, the 129top error will have the reason C<OSSL_STORE_R_UNREGISTERED_SCHEME>. 130 131These functions make no direct assumption regarding the pass phrase received 132from the password callback. 133The loaders may make assumptions, however. 134For example, the B<file:> scheme loader inherits the assumptions made by 135OpenSSL functionality that handles the different file types; this is mostly 136relevant for PKCS#12 objects. 137See L<passphrase-encoding(7)> for further information. 138 139=head1 RETURN VALUES 140 141OSSL_STORE_open() returns a pointer to a B<OSSL_STORE_CTX> on success, or 142NULL on failure. 143 144OSSL_STORE_load() returns a pointer to a B<OSSL_STORE_INFO> on success, or NULL 145on error or when end of data is reached. 146Use OSSL_STORE_error() and OSSL_STORE_eof() to determine the meaning of a 147returned NULL. 148 149OSSL_STORE_eof() returns 1 if the end of data has been reached 150or an error occurred, 0 otherwise. 151 152OSSL_STORE_error() returns 1 if an error occurred in an OSSL_STORE_load() call, 153otherwise 0. 154 155OSSL_STORE_ctrl() and OSSL_STORE_close() returns 1 on success, or 0 on failure. 156 157=head1 SEE ALSO 158 159L<ossl_store(7)>, L<OSSL_STORE_INFO(3)>, L<OSSL_STORE_register_loader(3)>, 160L<passphrase-encoding(7)> 161 162=head1 HISTORY 163 164OSSL_STORE_open_ex() was added in OpenSSL 3.0. 165 166B<OSSL_STORE_CTX>, OSSL_STORE_post_process_info_fn(), OSSL_STORE_open(), 167OSSL_STORE_ctrl(), OSSL_STORE_load(), OSSL_STORE_eof() and OSSL_STORE_close() 168were added in OpenSSL 1.1.1. 169 170Handling of NULL I<ctx> argument for OSSL_STORE_close() 171was introduced in OpenSSL 1.1.1h. 172 173OSSL_STORE_open_ex() was added in OpenSSL 3.0. 174 175OSSL_STORE_ctrl() and OSSL_STORE_vctrl() were deprecated in OpenSSL 3.0. 176 177=head1 COPYRIGHT 178 179Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved. 180 181Licensed under the Apache License 2.0 (the "License"). You may not use 182this file except in compliance with the License. You can obtain a copy 183in the file LICENSE in the source distribution or at 184L<https://www.openssl.org/source/license.html>. 185 186=cut 187