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>
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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):
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39        int OSSL_STORE_ctrl(OSSL_STORE_CTX *ctx, int cmd, ... /* args */);
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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
67       OSSL_PARAM(3) parameters in params can be set to further modify the
68       store operation.  The given post_process and post_process_data will be
69       reused by OSSL_STORE_load() to manipulate or drop the value to be
70       returned.  The post_process function drops values by returning NULL,
71       which will cause OSSL_STORE_load() to start its process over with
72       loading the next object, until post_process returns something other
73       than NULL, or the end of data is reached as indicated by
74       OSSL_STORE_eof().
75
76       OSSL_STORE_open() is similar to OSSL_STORE_open_ex() but uses NULL for
77       the params, the library context libctx and property query propq.
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79       OSSL_STORE_ctrl() takes a OSSL_STORE_CTX, and command number cmd and
80       more arguments not specified here.  The available loader specific
81       command numbers and arguments they each take depends on the loader
82       that's used and is documented together with that loader.
83
84       There are also global controls available:
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86       OSSL_STORE_C_USE_SECMEM
87           Controls if the loader should attempt to use secure memory for any
88           allocated OSSL_STORE_INFO and its contents.  This control expects
89           one argument, a pointer to an int that is expected to have the
90           value 1 (yes) or 0 (no).  Any other value is an error.
91
92       OSSL_STORE_load() takes a OSSL_STORE_CTX and tries to load the next
93       available object and return it wrapped with OSSL_STORE_INFO.
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95       OSSL_STORE_eof() takes a OSSL_STORE_CTX and checks if we've reached the
96       end of data.
97
98       OSSL_STORE_error() takes a OSSL_STORE_CTX and checks if an error
99       occurred in the last OSSL_STORE_load() call.  Note that it may still be
100       meaningful to try and load more objects, unless OSSL_STORE_eof() shows
101       that the end of data has been reached.
102
103       OSSL_STORE_close() takes a OSSL_STORE_CTX, closes the channel that was
104       opened by OSSL_STORE_open() and frees all other information that was
105       stored in the OSSL_STORE_CTX, as well as the OSSL_STORE_CTX itself.  If
106       ctx is NULL it does nothing.
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NOTES

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

126       OSSL_STORE_open() returns a pointer to a OSSL_STORE_CTX on success, or
127       NULL on failure.
128
129       OSSL_STORE_load() returns a pointer to a OSSL_STORE_INFO on success, or
130       NULL on error or when end of data is reached.  Use OSSL_STORE_error()
131       and OSSL_STORE_eof() to determine the meaning of a returned NULL.
132
133       OSSL_STORE_eof() returns 1 if the end of data has been reached or an
134       error occurred, 0 otherwise.
135
136       OSSL_STORE_error() returns 1 if an error occurred in an
137       OSSL_STORE_load() call, otherwise 0.
138
139       OSSL_STORE_ctrl() and OSSL_STORE_close() returns 1 on success, or 0 on
140       failure.
141

SEE ALSO

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

147       OSSL_STORE_open_ex() was added in OpenSSL 3.0.
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149       OSSL_STORE_CTX, OSSL_STORE_post_process_info_fn(), OSSL_STORE_open(),
150       OSSL_STORE_ctrl(), OSSL_STORE_load(), OSSL_STORE_eof() and
151       OSSL_STORE_close() were added in OpenSSL 1.1.1.
152
153       Handling of NULL ctx argument for OSSL_STORE_close() was introduced in
154       OpenSSL 1.1.1h.
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156       OSSL_STORE_open_ex() was added in OpenSSL 3.0.
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158       OSSL_STORE_ctrl() and OSSL_STORE_vctrl() were deprecated in OpenSSL
159       3.0.
160
162       Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved.
163
164       Licensed under the Apache License 2.0 (the "License").  You may not use
165       this file except in compliance with the License.  You can obtain a copy
166       in the file LICENSE in the source distribution or at
167       <https://www.openssl.org/source/license.html>.
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1713.0.9                             2023-07-27            OSSL_STORE_OPEN(3ossl)
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