1=pod
2
3=head1 NAME
4
5X509_NAME_get_index_by_NID, X509_NAME_get_index_by_OBJ, X509_NAME_get_entry,
6X509_NAME_entry_count, X509_NAME_get_text_by_NID, X509_NAME_get_text_by_OBJ -
7X509_NAME lookup and enumeration functions
8
9=head1 SYNOPSIS
10
11 #include <openssl/x509.h>
12
13 int X509_NAME_get_index_by_NID(const X509_NAME *name, int nid, int lastpos);
14 int X509_NAME_get_index_by_OBJ(const X509_NAME *name,
15                                const ASN1_OBJECT *obj, int lastpos);
16
17 int X509_NAME_entry_count(const X509_NAME *name);
18 X509_NAME_ENTRY *X509_NAME_get_entry(const X509_NAME *name, int loc);
19
20 int X509_NAME_get_text_by_NID(const X509_NAME *name, int nid,
21                               char *buf, int len);
22 int X509_NAME_get_text_by_OBJ(const X509_NAME *name, const ASN1_OBJECT *obj,
23                               char *buf, int len);
24
25=head1 DESCRIPTION
26
27These functions allow an B<X509_NAME> structure to be examined. The
28B<X509_NAME> structure is the same as the B<Name> type defined in
29RFC2459 (and elsewhere) and used for example in certificate subject
30and issuer names.
31
32X509_NAME_get_index_by_NID() and X509_NAME_get_index_by_OBJ() retrieve
33the next index matching B<nid> or B<obj> after B<lastpos>. B<lastpos>
34should initially be set to -1. If there are no more entries -1 is returned.
35If B<nid> is invalid (doesn't correspond to a valid OID) then -2 is returned.
36
37X509_NAME_entry_count() returns the total number of entries in B<name>.
38
39X509_NAME_get_entry() retrieves the B<X509_NAME_ENTRY> from B<name>
40corresponding to index B<loc>. Acceptable values for B<loc> run from
410 to (X509_NAME_entry_count(name) - 1). The value returned is an
42internal pointer which must not be freed.
43
44X509_NAME_get_text_by_NID(), X509_NAME_get_text_by_OBJ() retrieve
45the "text" from the first entry in B<name> which matches B<nid> or
46B<obj>, if no such entry exists -1 is returned. At most B<len> bytes
47will be written and the text written to B<buf> will be null
48terminated. The length of the output string written is returned
49excluding the terminating null. If B<buf> is <NULL> then the amount
50of space needed in B<buf> (excluding the final null) is returned.
51
52=head1 NOTES
53
54X509_NAME_get_text_by_NID() and X509_NAME_get_text_by_OBJ() should be
55considered deprecated because they
56have various limitations which make them
57of minimal use in practice. They can only find the first matching
58entry and will copy the contents of the field verbatim: this can
59be highly confusing if the target is a multicharacter string type
60like a BMPString or a UTF8String.
61
62For a more general solution X509_NAME_get_index_by_NID() or
63X509_NAME_get_index_by_OBJ() should be used followed by
64X509_NAME_get_entry() on any matching indices and then the
65various B<X509_NAME_ENTRY> utility functions on the result.
66
67The list of all relevant B<NID_*> and B<OBJ_* codes> can be found in
68the source code header files F<< <openssl/obj_mac.h> >> and/or
69F<< <openssl/objects.h> >>.
70
71Applications which could pass invalid NIDs to X509_NAME_get_index_by_NID()
72should check for the return value of -2. Alternatively the NID validity
73can be determined first by checking OBJ_nid2obj(nid) is not NULL.
74
75=head1 RETURN VALUES
76
77X509_NAME_get_index_by_NID() and X509_NAME_get_index_by_OBJ()
78return the index of the next matching entry or -1 if not found.
79X509_NAME_get_index_by_NID() can also return -2 if the supplied
80NID is invalid.
81
82X509_NAME_entry_count() returns the total number of entries, and 0
83for failure.
84
85X509_NAME_get_entry() returns an B<X509_NAME> pointer to the
86requested entry or B<NULL> if the index is invalid.
87
88=head1 EXAMPLES
89
90Process all entries:
91
92 int i;
93 X509_NAME_ENTRY *e;
94
95 for (i = 0; i < X509_NAME_entry_count(nm); i++) {
96     e = X509_NAME_get_entry(nm, i);
97     /* Do something with e */
98 }
99
100Process all commonName entries:
101
102 int lastpos = -1;
103 X509_NAME_ENTRY *e;
104
105 for (;;) {
106     lastpos = X509_NAME_get_index_by_NID(nm, NID_commonName, lastpos);
107     if (lastpos == -1)
108         break;
109     e = X509_NAME_get_entry(nm, lastpos);
110     /* Do something with e */
111 }
112
113=head1 SEE ALSO
114
115L<ERR_get_error(3)>, L<d2i_X509_NAME(3)>
116
117=head1 COPYRIGHT
118
119Copyright 2002-2021 The OpenSSL Project Authors. All Rights Reserved.
120
121Licensed under the Apache License 2.0 (the "License").  You may not use
122this file except in compliance with the License.  You can obtain a copy
123in the file LICENSE in the source distribution or at
124L<https://www.openssl.org/source/license.html>.
125
126=cut
127