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OSSL_STORE_open(3)                  OpenSSL                 OSSL_STORE_open(3)



NAME
       OSSL_STORE_CTX, OSSL_STORE_post_process_info_fn, OSSL_STORE_open,
       OSSL_STORE_open_ex, OSSL_STORE_ctrl, OSSL_STORE_load, OSSL_STORE_eof,
       OSSL_STORE_error, OSSL_STORE_close - Types and functions to read
       objects from a URI

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/store.h>

        typedef struct ossl_store_ctx_st OSSL_STORE_CTX;

        typedef OSSL_STORE_INFO *(*OSSL_STORE_post_process_info_fn)(OSSL_STORE_INFO *,
                                                                    void *);

        OSSL_STORE_CTX *OSSL_STORE_open(const char *uri, const UI_METHOD *ui_method,
                                        void *ui_data,
                                        OSSL_STORE_post_process_info_fn post_process,
                                        void *post_process_data);
        OSSL_STORE_CTX *
        OSSL_STORE_open_ex(const char *uri, OSSL_LIB_CTX *libctx, const char *propq,
                           const UI_METHOD *ui_method, void *ui_data,
                           const OSSL_PARAM params[],
                           OSSL_STORE_post_process_info_fn post_process,
                           void *post_process_data);

        OSSL_STORE_INFO *OSSL_STORE_load(OSSL_STORE_CTX *ctx);
        int OSSL_STORE_eof(OSSL_STORE_CTX *ctx);
        int OSSL_STORE_error(OSSL_STORE_CTX *ctx);
        int OSSL_STORE_close(OSSL_STORE_CTX *ctx);

       The following function has been deprecated since OpenSSL 3.0, and can
       be hidden entirely by defining OPENSSL_API_COMPAT with a suitable
       version value, see openssl_user_macros(7):

        int OSSL_STORE_ctrl(OSSL_STORE_CTX *ctx, int cmd, ... /* args */);

DESCRIPTION
       These functions help the application to fetch supported objects (see
       "SUPPORTED OBJECTS" in OSSL_STORE_INFO(3) for information on which
       those are) from a given URI. The general method to do so is to "open"
       the URI using OSSL_STORE_open(), read each available and supported
       object using OSSL_STORE_load() as long as OSSL_STORE_eof() hasn't been
       reached, and finish it off with OSSL_STORE_close().

       The retrieved information is stored in a OSSL_STORE_INFO, which is
       further described in OSSL_STORE_INFO(3).

   Types
       OSSL_STORE_CTX is a context variable that holds all the internal
       information for OSSL_STORE_open(), OSSL_STORE_open_ex(),
       OSSL_STORE_load(), OSSL_STORE_eof() and OSSL_STORE_close() to work
       together.

   Functions
       OSSL_STORE_open_ex() takes a uri or path uri, password UI method
       ui_method with associated data ui_data, and post processing callback
       post_process with associated data post_process_data, a library context
       libctx with an associated property query propq, and opens a channel to
       the data located at the URI and returns a OSSL_STORE_CTX with all
       necessary internal information.  The given ui_method and ui_data will
       be reused by all functions that use OSSL_STORE_CTX when interaction is
       needed, for instance to provide a password.  The auxiliary
       OSSL_PARAM(3) parameters in params can be set to further modify the
       store operation.  The given post_process and post_process_data will be
       reused by OSSL_STORE_load() to manipulate or drop the value to be
       returned.  The post_process function drops values by returning NULL,
       which will cause OSSL_STORE_load() to start its process over with
       loading the next object, until post_process returns something other
       than NULL, or the end of data is reached as indicated by
       OSSL_STORE_eof().

       OSSL_STORE_open() is similar to OSSL_STORE_open_ex() but uses NULL for
       the params, the library context libctx and property query propq.

       OSSL_STORE_ctrl() takes a OSSL_STORE_CTX, and command number cmd and
       more arguments not specified here.  The available loader specific
       command numbers and arguments they each take depends on the loader
       that's used and is documented together with that loader.

       There are also global controls available:

       OSSL_STORE_C_USE_SECMEM
           Controls if the loader should attempt to use secure memory for any
           allocated OSSL_STORE_INFO and its contents.  This control expects
           one argument, a pointer to an int that is expected to have the
           value 1 (yes) or 0 (no).  Any other value is an error.

       OSSL_STORE_load() takes a OSSL_STORE_CTX and tries to load the next
       available object and return it wrapped with OSSL_STORE_INFO.

       OSSL_STORE_eof() takes a OSSL_STORE_CTX and checks if we've reached the
       end of data.

       OSSL_STORE_error() takes a OSSL_STORE_CTX and checks if an error
       occurred in the last OSSL_STORE_load() call.  Note that it may still be
       meaningful to try and load more objects, unless OSSL_STORE_eof() shows
       that the end of data has been reached.

       OSSL_STORE_close() takes a OSSL_STORE_CTX, closes the channel that was
       opened by OSSL_STORE_open() and frees all other information that was
       stored in the OSSL_STORE_CTX, as well as the OSSL_STORE_CTX itself.  If
       ctx is NULL it does nothing.

NOTES
       A string without a scheme prefix (that is, a non-URI string) is
       implicitly interpreted as using the file: scheme.

       There are some tools that can be used together with OSSL_STORE_open()
       to determine if any failure is caused by an unparsable URI, or if it's
       a different error (such as memory allocation failures); if the URI was
       parsable but the scheme unregistered, the top error will have the
       reason "OSSL_STORE_R_UNREGISTERED_SCHEME".

       These functions make no direct assumption regarding the pass phrase
       received from the password callback.  The loaders may make assumptions,
       however.  For example, the file: scheme loader inherits the assumptions
       made by OpenSSL functionality that handles the different file types;
       this is mostly relevant for PKCS#12 objects.  See
       passphrase-encoding(7) for further information.

RETURN VALUES
       OSSL_STORE_open() returns a pointer to a OSSL_STORE_CTX on success, or
       NULL on failure.

       OSSL_STORE_load() returns a pointer to a OSSL_STORE_INFO on success, or
       NULL on error or when end of data is reached.  Use OSSL_STORE_error()
       and OSSL_STORE_eof() to determine the meaning of a returned NULL.

       OSSL_STORE_eof() returns 1 if the end of data has been reached or an
       error occurred, 0 otherwise.

       OSSL_STORE_error() returns 1 if an error occurred in an
       OSSL_STORE_load() call, otherwise 0.

       OSSL_STORE_ctrl() and OSSL_STORE_close() returns 1 on success, or 0 on
       failure.

SEE ALSO
       ossl_store(7), OSSL_STORE_INFO(3), OSSL_STORE_register_loader(3),
       passphrase-encoding(7)

HISTORY
       OSSL_STORE_open_ex() was added in OpenSSL 3.0.

       OSSL_STORE_CTX, OSSL_STORE_post_process_info_fn(), OSSL_STORE_open(),
       OSSL_STORE_ctrl(), OSSL_STORE_load(), OSSL_STORE_eof() and
       OSSL_STORE_close() were added in OpenSSL 1.1.1.

       Handling of NULL ctx argument for OSSL_STORE_close() was introduced in
       OpenSSL 1.1.1h.

       OSSL_STORE_open_ex() was added in OpenSSL 3.0.

       OSSL_STORE_ctrl() and OSSL_STORE_vctrl() were deprecated in OpenSSL
       3.0.

COPYRIGHT
       Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.



3.0.12                            2023-05-07                OSSL_STORE_open(3)