=pod

=head1 NAME

X509_LOOKUP_METHOD,
X509_LOOKUP_meth_new, X509_LOOKUP_meth_free, X509_LOOKUP_meth_set_new_item,
X509_LOOKUP_meth_get_new_item, X509_LOOKUP_meth_set_free,
X509_LOOKUP_meth_get_free, X509_LOOKUP_meth_set_init,
X509_LOOKUP_meth_get_init, X509_LOOKUP_meth_set_shutdown,
X509_LOOKUP_meth_get_shutdown,
X509_LOOKUP_ctrl_fn, X509_LOOKUP_meth_set_ctrl, X509_LOOKUP_meth_get_ctrl,
X509_LOOKUP_get_by_subject_fn, X509_LOOKUP_meth_set_get_by_subject,
X509_LOOKUP_meth_get_get_by_subject,
X509_LOOKUP_get_by_issuer_serial_fn, X509_LOOKUP_meth_set_get_by_issuer_serial,
X509_LOOKUP_meth_get_get_by_issuer_serial,
X509_LOOKUP_get_by_fingerprint_fn, X509_LOOKUP_meth_set_get_by_fingerprint,
X509_LOOKUP_meth_get_get_by_fingerprint,
X509_LOOKUP_get_by_alias_fn, X509_LOOKUP_meth_set_get_by_alias,
X509_LOOKUP_meth_get_get_by_alias,
X509_OBJECT_set1_X509, X509_OBJECT_set1_X509_CRL
- Routines to build up X509_LOOKUP methods

=head1 SYNOPSIS

 #include <openssl/x509_vfy.h>

 typedef x509_lookup_method_st X509_LOOKUP_METHOD;

 X509_LOOKUP_METHOD *X509_LOOKUP_meth_new(const char *name);
 void X509_LOOKUP_meth_free(X509_LOOKUP_METHOD *method);

 int X509_LOOKUP_meth_set_new_item(X509_LOOKUP_METHOD *method,
                                   int (*new_item) (X509_LOOKUP *ctx));
 int (*X509_LOOKUP_meth_get_new_item(const X509_LOOKUP_METHOD* method))
     (X509_LOOKUP *ctx);

 int X509_LOOKUP_meth_set_free(X509_LOOKUP_METHOD *method,
                               void (*free) (X509_LOOKUP *ctx));
 void (*X509_LOOKUP_meth_get_free(const X509_LOOKUP_METHOD* method))
     (X509_LOOKUP *ctx);

 int X509_LOOKUP_meth_set_init(X509_LOOKUP_METHOD *method,
                               int (*init) (X509_LOOKUP *ctx));
 int (*X509_LOOKUP_meth_get_init(const X509_LOOKUP_METHOD* method))
     (X509_LOOKUP *ctx);

 int X509_LOOKUP_meth_set_shutdown(X509_LOOKUP_METHOD *method,
                                   int (*shutdown) (X509_LOOKUP *ctx));
 int (*X509_LOOKUP_meth_get_shutdown(const X509_LOOKUP_METHOD* method))
     (X509_LOOKUP *ctx);

 typedef int (*X509_LOOKUP_ctrl_fn)(X509_LOOKUP *ctx, int cmd, const char *argc,
                                    long argl, char **ret);
 int X509_LOOKUP_meth_set_ctrl(X509_LOOKUP_METHOD *method,
     X509_LOOKUP_ctrl_fn ctrl_fn);
 X509_LOOKUP_ctrl_fn X509_LOOKUP_meth_get_ctrl(const X509_LOOKUP_METHOD *method);

 typedef int (*X509_LOOKUP_get_by_subject_fn)(X509_LOOKUP *ctx,
                                              X509_LOOKUP_TYPE type,
                                              X509_NAME *name,
                                              X509_OBJECT *ret);
 int X509_LOOKUP_meth_set_get_by_subject(X509_LOOKUP_METHOD *method,
     X509_LOOKUP_get_by_subject_fn fn);
 X509_LOOKUP_get_by_subject_fn X509_LOOKUP_meth_get_get_by_subject(
     const X509_LOOKUP_METHOD *method);

 typedef int (*X509_LOOKUP_get_by_issuer_serial_fn)(X509_LOOKUP *ctx,
                                                    X509_LOOKUP_TYPE type,
                                                    X509_NAME *name,
                                                    ASN1_INTEGER *serial,
                                                    X509_OBJECT *ret);
 int X509_LOOKUP_meth_set_get_by_issuer_serial(
     X509_LOOKUP_METHOD *method, X509_LOOKUP_get_by_issuer_serial_fn fn);
 X509_LOOKUP_get_by_issuer_serial_fn X509_LOOKUP_meth_get_get_by_issuer_serial(
     const X509_LOOKUP_METHOD *method);

 typedef int (*X509_LOOKUP_get_by_fingerprint_fn)(X509_LOOKUP *ctx,
                                                  X509_LOOKUP_TYPE type,
                                                  const unsigned char* bytes,
                                                  int len,
                                                  X509_OBJECT *ret);
 int X509_LOOKUP_meth_set_get_by_fingerprint(X509_LOOKUP_METHOD *method,
     X509_LOOKUP_get_by_fingerprint_fn fn);
 X509_LOOKUP_get_by_fingerprint_fn X509_LOOKUP_meth_get_get_by_fingerprint(
     const X509_LOOKUP_METHOD *method);

 typedef int (*X509_LOOKUP_get_by_alias_fn)(X509_LOOKUP *ctx,
                                            X509_LOOKUP_TYPE type,
                                            const char *str,
                                            int len,
                                            X509_OBJECT *ret);
 int X509_LOOKUP_meth_set_get_by_alias(X509_LOOKUP_METHOD *method,
     X509_LOOKUP_get_by_alias_fn fn);
 X509_LOOKUP_get_by_alias_fn X509_LOOKUP_meth_get_get_by_alias(
     const X509_LOOKUP_METHOD *method);

 int X509_OBJECT_set1_X509(X509_OBJECT *a, X509 *obj);
 int X509_OBJECT_set1_X509_CRL(X509_OBJECT *a, X509_CRL *obj);

=head1 DESCRIPTION

The B<X509_LOOKUP_METHOD> type is a structure used for the implementation of new
X509_LOOKUP types. It provides a set of functions used by OpenSSL for the
implementation of various X509 and X509_CRL lookup capabilities. One instance
of an X509_LOOKUP_METHOD can be associated to many instantiations of an
B<X509_LOOKUP> structure.

X509_LOOKUP_meth_new() creates a new B<X509_LOOKUP_METHOD> structure. It should
be given a human-readable string containing a brief description of the lookup
method.

X509_LOOKUP_meth_free() destroys a B<X509_LOOKUP_METHOD> structure.

X509_LOOKUP_get_new_item() and X509_LOOKUP_set_new_item() get and set the
function that is called when an B<X509_LOOKUP> object is created with
X509_LOOKUP_new(). If an X509_LOOKUP_METHOD requires any per-X509_LOOKUP
specific data, the supplied new_item function should allocate this data and
invoke L<X509_LOOKUP_set_method_data(3)>.

X509_LOOKUP_get_free() and X509_LOOKUP_set_free() get and set the function
that is used to free any method data that was allocated and set from within
new_item function.

X509_LOOKUP_meth_get_init() and X509_LOOKUP_meth_set_init() get and set the
function that is used to initialize the method data that was set with
L<X509_LOOKUP_set_method_data(3)> as part of the new_item routine.

X509_LOOKUP_meth_get_shutdown() and X509_LOOKUP_meth_set_shutdown() get and set
the function that is used to shut down the method data whose state was
previously initialized in the init function.

X509_LOOKUP_meth_get_ctrl() and X509_LOOKUP_meth_set_ctrl() get and set a
function to be used to handle arbitrary control commands issued by
X509_LOOKUP_ctrl(). The control function is given the X509_LOOKUP
B<ctx>, along with the arguments passed by X509_LOOKUP_ctrl. B<cmd> is
an arbitrary integer that defines some operation. B<argc> is a pointer
to an array of characters. B<argl> is an integer. B<ret>, if set,
points to a location where any return data should be written to. How
B<argc> and B<argl> are used depends entirely on the control function.


X509_LOOKUP_set_get_by_subject(), X509_LOOKUP_set_get_by_issuer_serial(),
X509_LOOKUP_set_get_by_fingerprint(), X509_LOOKUP_set_get_by_alias() set
the functions used to retrieve an X509 or X509_CRL object by the object's
subject, issuer, fingerprint, and alias respectively. These functions are given
the X509_LOOKUP context, the type of the X509_OBJECT being requested, parameters
related to the lookup, and an X509_OBJECT that will receive the requested
object.

Implementations must add objects they find to the B<X509_STORE> object
using X509_STORE_add_cert() or X509_STORE_add_crl().  This increments
its reference count.  However, the X509_STORE_CTX_get_by_subject()
function also increases the reference count which leads to one too
many references being held.  Therefore applications should
additionally call X509_free() or X509_CRL_free() to decrement the
reference count again.

Implementations should also use either X509_OBJECT_set1_X509() or
X509_OBJECT_set1_X509_CRL() to set the result.  Note that this also
increments the result's reference count.

Any method data that was created as a result of the new_item function
set by X509_LOOKUP_meth_set_new_item() can be accessed with
L<X509_LOOKUP_get_method_data(3)>. The B<X509_STORE> object that owns the
X509_LOOKUP may be accessed with L<X509_LOOKUP_get_store(3)>. Successful
lookups should return 1, and unsuccessful lookups should return 0.

X509_LOOKUP_get_get_by_subject(), X509_LOOKUP_get_get_by_issuer_serial(),
X509_LOOKUP_get_get_by_fingerprint(), X509_LOOKUP_get_get_by_alias() retrieve
the function set by the corresponding setter.

=head1 RETURN VALUES

The B<X509_LOOKUP_meth_set> functions return 1 on success or 0 on error.

The B<X509_LOOKUP_meth_get> functions return the corresponding function
pointers.

=head1 SEE ALSO

L<X509_STORE_new(3)>, L<SSL_CTX_set_cert_store(3)>

=head1 HISTORY

The functions described here were added in OpenSSL 1.1.0i.

=head1 COPYRIGHT

Copyright 2018-2020 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
