=pod

=head1 NAME

ossl_store - Store retrieval functions

=head1 SYNOPSIS

=for comment generic

#include <openssl/store.h>

=head1 DESCRIPTION

=head2 General

A STORE is a layer of functionality to retrieve a number of supported
objects from a repository of any kind, addressable as a filename or
as a URI.

The functionality supports the pattern "open a channel to the
repository", "loop and retrieve one object at a time", and "finish up
by closing the channel".

The retrieved objects are returned as a wrapper type B<OSSL_STORE_INFO>,
from which an OpenSSL type can be retrieved.

=head2 URI schemes and loaders

Support for a URI scheme is called a STORE "loader", and can be added
dynamically from the calling application or from a loadable engine.

Support for the 'file' scheme is built into C<libcrypto>.
See L<ossl_store-file(7)> for more information.

=head2 UI_METHOD and pass phrases

The B<OSS_STORE> API does nothing to enforce any specific format or
encoding on the pass phrase that the B<UI_METHOD> provides.  However,
the pass phrase is expected to be UTF-8 encoded.  The result of any
other encoding is undefined.

=head1 EXAMPLES

=head2 A generic call

 OSSL_STORE_CTX *ctx = OSSL_STORE_open("file:/foo/bar/data.pem");

 /*
  * OSSL_STORE_eof() simulates file semantics for any repository to signal
  * that no more data can be expected
  */
 while (!OSSL_STORE_eof(ctx)) {
     OSSL_STORE_INFO *info = OSSL_STORE_load(ctx);

     /*
      * Do whatever is necessary with the OSSL_STORE_INFO,
      * here just one example
      */
     switch (OSSL_STORE_INFO_get_type(info)) {
     case OSSL_STORE_INFO_X509:
         /* Print the X.509 certificate text */
         X509_print_fp(stdout, OSSL_STORE_INFO_get0_CERT(info));
         /* Print the X.509 certificate PEM output */
         PEM_write_X509(stdout, OSSL_STORE_INFO_get0_CERT(info));
         break;
     }
 }

 OSSL_STORE_close(ctx);

=head1 SEE ALSO

L<OSSL_STORE_INFO(3)>, L<OSSL_STORE_LOADER(3)>,
L<OSSL_STORE_open(3)>, L<OSSL_STORE_expect(3)>,
L<OSSL_STORE_SEARCH(3)>

=head1 COPYRIGHT

Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (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
L<https://www.openssl.org/source/license.html>.

=cut
