1OSSL_STORE_OPEN(3ossl)              OpenSSL             OSSL_STORE_OPEN(3ossl)
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NAME

6       OSSL_STORE_CTX, OSSL_STORE_post_process_info_fn, OSSL_STORE_open,
7       OSSL_STORE_open_ex, OSSL_STORE_ctrl, OSSL_STORE_load, OSSL_STORE_eof,
8       OSSL_STORE_error, OSSL_STORE_close - Types and functions to read
9       objects from a URI
10

SYNOPSIS

12        #include <openssl/store.h>
13
14        typedef struct ossl_store_ctx_st OSSL_STORE_CTX;
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16        typedef OSSL_STORE_INFO *(*OSSL_STORE_post_process_info_fn)(OSSL_STORE_INFO *,
17                                                                    void *);
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19        OSSL_STORE_CTX *OSSL_STORE_open(const char *uri, const UI_METHOD *ui_method,
20                                        void *ui_data,
21                                        OSSL_STORE_post_process_info_fn post_process,
22                                        void *post_process_data);
23        OSSL_STORE_CTX *
24        OSSL_STORE_open_ex(const char *uri, OSSL_LIB_CTX *libctx, const char *propq,
25                           const UI_METHOD *ui_method, void *ui_data,
26                           const OSSL_PARAM params[],
27                           OSSL_STORE_post_process_info_fn post_process,
28                           void *post_process_data);
29
30        OSSL_STORE_INFO *OSSL_STORE_load(OSSL_STORE_CTX *ctx);
31        int OSSL_STORE_eof(OSSL_STORE_CTX *ctx);
32        int OSSL_STORE_error(OSSL_STORE_CTX *ctx);
33        int OSSL_STORE_close(OSSL_STORE_CTX *ctx);
34
35       The following function has been deprecated since OpenSSL 3.0, and can
36       be hidden entirely by defining OPENSSL_API_COMPAT with a suitable
37       version value, see openssl_user_macros(7):
38
39        int OSSL_STORE_ctrl(OSSL_STORE_CTX *ctx, int cmd, ... /* args */);
40

DESCRIPTION

42       These functions help the application to fetch supported objects (see
43       "SUPPORTED OBJECTS" in OSSL_STORE_INFO(3) for information on which
44       those are) from a given URI.  The general method to do so is to "open"
45       the URI using OSSL_STORE_open(), read each available and supported
46       object using OSSL_STORE_load() as long as OSSL_STORE_eof() hasn't been
47       reached, and finish it off with OSSL_STORE_close().
48
49       The retrieved information is stored in a OSSL_STORE_INFO, which is
50       further described in OSSL_STORE_INFO(3).
51
52   Types
53       OSSL_STORE_CTX is a context variable that holds all the internal
54       information for OSSL_STORE_open(), OSSL_STORE_open_ex(),
55       OSSL_STORE_load(), OSSL_STORE_eof() and OSSL_STORE_close() to work
56       together.
57
58   Functions
59       OSSL_STORE_open_ex() takes a uri or path uri, password UI method
60       ui_method with associated data ui_data, and post processing callback
61       post_process with associated data post_process_data, a library context
62       libctx with an associated property query propq, and opens a channel to
63       the data located at the URI and returns a OSSL_STORE_CTX with all
64       necessary internal information.  The given ui_method and ui_data will
65       be reused by all functions that use OSSL_STORE_CTX when interaction is
66       needed, for instance to provide a password.  The auxiliary OSSL_PARAM
67       parameters in params can be set to further modify the store operation.
68       The given post_process and post_process_data will be reused by
69       OSSL_STORE_load() to manipulate or drop the value to be returned.  The
70       post_process function drops values by returning NULL, which will cause
71       OSSL_STORE_load() to start its process over with loading the next
72       object, until post_process returns something other than NULL, or the
73       end of data is reached as indicated by OSSL_STORE_eof().
74
75       OSSL_STORE_open() is similar to OSSL_STORE_open_ex() but uses NULL for
76       the params, the library context libctx and property query propq.
77
78       OSSL_STORE_ctrl() takes a OSSL_STORE_CTX, and command number cmd and
79       more arguments not specified here.  The available loader specific
80       command numbers and arguments they each take depends on the loader
81       that's used and is documented together with that loader.
82
83       There are also global controls available:
84
85       OSSL_STORE_C_USE_SECMEM
86           Controls if the loader should attempt to use secure memory for any
87           allocated OSSL_STORE_INFO and its contents.  This control expects
88           one argument, a pointer to an int that is expected to have the
89           value 1 (yes) or 0 (no).  Any other value is an error.
90
91       OSSL_STORE_load() takes a OSSL_STORE_CTX and tries to load the next
92       available object and return it wrapped with OSSL_STORE_INFO.
93
94       OSSL_STORE_eof() takes a OSSL_STORE_CTX and checks if we've reached the
95       end of data.
96
97       OSSL_STORE_error() takes a OSSL_STORE_CTX and checks if an error
98       occurred in the last OSSL_STORE_load() call.  Note that it may still be
99       meaningful to try and load more objects, unless OSSL_STORE_eof() shows
100       that the end of data has been reached.
101
102       OSSL_STORE_close() takes a OSSL_STORE_CTX, closes the channel that was
103       opened by OSSL_STORE_open() and frees all other information that was
104       stored in the OSSL_STORE_CTX, as well as the OSSL_STORE_CTX itself.  If
105       ctx is NULL it does nothing.
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NOTES

108       A string without a scheme prefix (that is, a non-URI string) is
109       implicitly interpreted as using the file: scheme.
110
111       There are some tools that can be used together with OSSL_STORE_open()
112       to determine if any failure is caused by an unparsable URI, or if it's
113       a different error (such as memory allocation failures); if the URI was
114       parsable but the scheme unregistered, the top error will have the
115       reason "OSSL_STORE_R_UNREGISTERED_SCHEME".
116
117       These functions make no direct assumption regarding the pass phrase
118       received from the password callback.  The loaders may make assumptions,
119       however.  For example, the file: scheme loader inherits the assumptions
120       made by OpenSSL functionality that handles the different file types;
121       this is mostly relevant for PKCS#12 objects.  See
122       passphrase-encoding(7) for further information.
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RETURN VALUES

125       OSSL_STORE_open() returns a pointer to a OSSL_STORE_CTX on success, or
126       NULL on failure.
127
128       OSSL_STORE_load() returns a pointer to a OSSL_STORE_INFO on success, or
129       NULL on error or when end of data is reached.  Use OSSL_STORE_error()
130       and OSSL_STORE_eof() to determine the meaning of a returned NULL.
131
132       OSSL_STORE_eof() returns 1 if the end of data has been reached or an
133       error occurred, 0 otherwise.
134
135       OSSL_STORE_error() returns 1 if an error occurred in an
136       OSSL_STORE_load() call, otherwise 0.
137
138       OSSL_STORE_ctrl() and OSSL_STORE_close() returns 1 on success, or 0 on
139       failure.
140

SEE ALSO

142       ossl_store(7), OSSL_STORE_INFO(3), OSSL_STORE_register_loader(3),
143       passphrase-encoding(7)
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HISTORY

146       OSSL_STORE_open_ex() was added in OpenSSL 3.0.
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148       OSSL_STORE_CTX, OSSL_STORE_post_process_info_fn(), OSSL_STORE_open(),
149       OSSL_STORE_ctrl(), OSSL_STORE_load(), OSSL_STORE_eof() and
150       OSSL_STORE_close() were added in OpenSSL 1.1.1.
151
152       Handling of NULL ctx argument for OSSL_STORE_close() was introduced in
153       OpenSSL 1.1.1h.
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155       OSSL_STORE_open_ex() was added in OpenSSL 3.0.
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157       OSSL_STORE_ctrl() and OSSL_STORE_vctrl() were deprecated in OpenSSL
158       3.0.
159
161       Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved.
162
163       Licensed under the Apache License 2.0 (the "License").  You may not use
164       this file except in compliance with the License.  You can obtain a copy
165       in the file LICENSE in the source distribution or at
166       <https://www.openssl.org/source/license.html>.
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1703.0.5                             2022-07-05            OSSL_STORE_OPEN(3ossl)
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