5 OSSL_STORE_CTX, OSSL_STORE_post_process_info_fn, OSSL_STORE_open,
6 OSSL_STORE_ctrl, OSSL_STORE_load, OSSL_STORE_eof, OSSL_STORE_error,
7 OSSL_STORE_close - Types and functions to read objects from a URI
11 #include <openssl/store.h>
13 typedef struct ossl_store_ctx_st OSSL_STORE_CTX;
15 typedef OSSL_STORE_INFO *(*OSSL_STORE_post_process_info_fn)(OSSL_STORE_INFO *,
18 OSSL_STORE_CTX *OSSL_STORE_open(const char *uri, const UI_METHOD *ui_method,
20 OSSL_STORE_post_process_info_fn post_process,
21 void *post_process_data);
22 int OSSL_STORE_ctrl(OSSL_STORE_CTX *ctx, int cmd, ... /* args */);
23 OSSL_STORE_INFO *OSSL_STORE_load(OSSL_STORE_CTX *ctx);
24 int OSSL_STORE_eof(OSSL_STORE_CTX *ctx);
25 int OSSL_STORE_error(OSSL_STORE_CTX *ctx);
26 int OSSL_STORE_close(OSSL_STORE_CTX *ctx);
30 These functions help the application to fetch supported objects (see
31 L<OSSL_STORE_INFO(3)/SUPPORTED OBJECTS> for information on which those are)
32 from a given URI (see L</SUPPORTED SCHEMES> for more information on
33 the supported URI schemes).
34 The general method to do so is to "open" the URI using OSSL_STORE_open(),
35 read each available and supported object using OSSL_STORE_load() as long as
36 OSSL_STORE_eof() hasn't been reached, and finish it off with OSSL_STORE_close().
38 The retrieved information is stored in a B<OSSL_STORE_INFO>, which is further
39 described in L<OSSL_STORE_INFO(3)>.
43 B<OSSL_STORE_CTX> is a context variable that holds all the internal
44 information for OSSL_STORE_open(), OSSL_STORE_load(), OSSL_STORE_eof() and
45 OSSL_STORE_close() to work together.
49 OSSL_STORE_open() takes a uri or path B<uri>, password UI method
50 B<ui_method> with associated data B<ui_data>, and post processing
51 callback B<post_process> with associated data B<post_process_data>,
52 opens a channel to the data located at that URI and returns a
53 B<OSSL_STORE_CTX> with all necessary internal information.
54 The given B<ui_method> and B<ui_data_data> will be reused by all
55 functions that use B<OSSL_STORE_CTX> when interaction is needed.
56 The given B<post_process> and B<post_process_data> will be reused by
57 OSSL_STORE_load() to manipulate or drop the value to be returned.
59 OSSL_STORE_ctrl() takes a B<OSSL_STORE_CTX>, and command number B<cmd> and
60 more arguments not specified here.
61 The available loader specific command numbers and arguments they each
62 take depends on the loader that's used and is documented together with
65 There are also global controls available:
69 =item B<OSSL_STORE_C_USE_SECMEM>
71 Controls if the loader should attempt to use secure memory for any
72 allocated B<OSSL_STORE_INFO> and its contents.
73 This control expects one argument, a pointer to an B<int> that is expected to
74 have the value 1 (yes) or 0 (no).
75 Any other value is an error.
79 OSSL_STORE_load() takes a B<OSSL_STORE_CTX>, tries to load the next available
80 object and return it wrapped with B<OSSL_STORE_INFO>.
82 OSSL_STORE_eof() takes a B<OSSL_STORE_CTX> and checks if we've reached the end
85 OSSL_STORE_error() takes a B<OSSL_STORE_CTX> and checks if an error occured in
86 the last OSSL_STORE_load() call.
87 Note that it may still be meaningful to try and load more objects, unless
88 OSSL_STORE_eof() shows that the end of data has been reached.
90 OSSL_STORE_close() takes a B<OSSL_STORE_CTX>, closes the channel that was opened
91 by OSSL_STORE_open() and frees all other information that was stored in the
92 B<OSSL_STORE_CTX>, as well as the B<OSSL_STORE_CTX> itself.
94 =head1 SUPPORTED SCHEMES
96 The basic supported scheme is B<file:>.
97 Any other scheme can be added dynamically, using
98 OSSL_STORE_register_loader().
102 When unsure whether a given string contains a simple file or directory
103 reference, or if it's a full blown URI, the question is how to figure
105 One way is to try OSSL_STORE_open_file() and if that fails, try
107 The other way is the other way around.
108 Either way you choose, there are corner cases,
109 F<file:/foo/bar/cookie.txt> might very will be a simple file reference
110 on a system that supports the notion of volumes.
112 This manual won't tell you which way is better, that's up to each
113 application developer to decide on their own.
114 However, there are some tools that can be used together with
115 OSSL_STORE_open() to determine if any failure is caused by an unparsable
116 URI, or if it's a different error (such as memory allocation
117 failures); if the URI was parsable but the scheme unregistered, the
118 top error will have the reason C<OSSL_STORE_R_UNREGISTERED_SCHEME>.
119 If you decide to use OSSL_STORE_open() with OSSL_STORE_open_file() as a
120 fallback, those reasons can be good tools to decide if the fallback
121 should be taken or not.
125 OSSL_STORE_open() returns a pointer to a B<OSSL_STORE_CTX> on success, or
128 OSSL_STORE_load() returns a pointer to a B<OSSL_STORE_INFO> on success, or
129 B<NULL> on error or when end of data is reached.
130 Use OSSL_STORE_error() and OSSL_STORE_eof() to determine the meaning of a
133 OSSL_STORE_eof() returns 1 if the end of data has been reached, otherwise
136 OSSL_STORE_error() returns 1 if an error occured in a OSSL_STORE_load() call,
139 OSSL_STORE_ctrl() and OSSL_STORE_close() returns 1 on success, or 0 on failure.
143 L<ossl_store(7)>, L<OSSL_STORE_INFO(3)>, L<OSSL_STORE_register_loader(3)>
147 OSSL_STORE_CTX(), OSSL_STORE_post_process_info_fn(), OSSL_STORE_open(),
148 OSSL_STORE_ctrl(), OSSL_STORE_load(), OSSL_STORE_eof() and OSSL_STORE_close()
149 were added to OpenSSL 1.1.1.
153 Copyright 2016-2017 The OpenSSL Project Authors. All Rights Reserved.
155 Licensed under the OpenSSL license (the "License"). You may not use
156 this file except in compliance with the License. You can obtain a copy
157 in the file LICENSE in the source distribution or at
158 L<https://www.openssl.org/source/license.html>.