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(X509_NAME *name, int nid, int lastpos);
14 int X509_NAME_get_index_by_OBJ(X509_NAME *name, const ASN1_OBJECT *obj, int lastpos);
15
16 int X509_NAME_entry_count(const X509_NAME *name);
17 X509_NAME_ENTRY *X509_NAME_get_entry(const X509_NAME *name, int loc);
18
19 int X509_NAME_get_text_by_NID(X509_NAME *name, int nid, char *buf, int len);
20 int X509_NAME_get_text_by_OBJ(X509_NAME *name, const ASN1_OBJECT *obj, char *buf, int len);
21
22=head1 DESCRIPTION
23
24These functions allow an B<X509_NAME> structure to be examined. The
25B<X509_NAME> structure is the same as the B<Name> type defined in
26RFC2459 (and elsewhere) and used for example in certificate subject
27and issuer names.
28
29X509_NAME_get_index_by_NID() and X509_NAME_get_index_by_OBJ() retrieve
30the next index matching B<nid> or B<obj> after B<lastpos>. B<lastpos>
31should initially be set to -1. If there are no more entries -1 is returned.
32If B<nid> is invalid (doesn't correspond to a valid OID) then -2 is returned.
33
34X509_NAME_entry_count() returns the total number of entries in B<name>.
35
36X509_NAME_get_entry() retrieves the B<X509_NAME_ENTRY> from B<name>
37corresponding to index B<loc>. Acceptable values for B<loc> run from
380 to (X509_NAME_entry_count(name) - 1). The value returned is an
39internal pointer which must not be freed.
40
41X509_NAME_get_text_by_NID(), X509_NAME_get_text_by_OBJ() retrieve
42the "text" from the first entry in B<name> which matches B<nid> or
43B<obj>, if no such entry exists -1 is returned. At most B<len> bytes
44will be written and the text written to B<buf> will be null
45terminated. The length of the output string written is returned
46excluding the terminating null. If B<buf> is <NULL> then the amount
47of space needed in B<buf> (excluding the final null) is returned.
48
49=head1 NOTES
50
51X509_NAME_get_text_by_NID() and X509_NAME_get_text_by_OBJ() should be
52considered deprecated because they
53have various limitations which make them
54of minimal use in practice. They can only find the first matching
55entry and will copy the contents of the field verbatim: this can
56be highly confusing if the target is a multicharacter string type
57like a BMPString or a UTF8String.
58
59For a more general solution X509_NAME_get_index_by_NID() or
60X509_NAME_get_index_by_OBJ() should be used followed by
61X509_NAME_get_entry() on any matching indices and then the
62various B<X509_NAME_ENTRY> utility functions on the result.
63
64The list of all relevant B<NID_*> and B<OBJ_* codes> can be found in
65the source code header files E<lt>openssl/obj_mac.hE<gt> and/or
66E<lt>openssl/objects.hE<gt>.
67
68Applications which could pass invalid NIDs to X509_NAME_get_index_by_NID()
69should check for the return value of -2. Alternatively the NID validity
70can be determined first by checking OBJ_nid2obj(nid) is not NULL.
71
72=head1 RETURN VALUES
73
74X509_NAME_get_index_by_NID() and X509_NAME_get_index_by_OBJ()
75return the index of the next matching entry or -1 if not found.
76X509_NAME_get_index_by_NID() can also return -2 if the supplied
77NID is invalid.
78
79X509_NAME_entry_count() returns the total number of entries.
80
81X509_NAME_get_entry() returns an B<X509_NAME> pointer to the
82requested entry or B<NULL> if the index is invalid.
83
84=head1 EXAMPLES
85
86Process all entries:
87
88 int i;
89 X509_NAME_ENTRY *e;
90
91 for (i = 0; i < X509_NAME_entry_count(nm); i++) {
92     e = X509_NAME_get_entry(nm, i);
93     /* Do something with e */
94 }
95
96Process all commonName entries:
97
98 int lastpos = -1;
99 X509_NAME_ENTRY *e;
100
101 for (;;) {
102     lastpos = X509_NAME_get_index_by_NID(nm, NID_commonName, lastpos);
103     if (lastpos == -1)
104         break;
105     e = X509_NAME_get_entry(nm, lastpos);
106     /* Do something with e */
107 }
108
109=head1 SEE ALSO
110
111L<ERR_get_error(3)>, L<d2i_X509_NAME(3)>
112
113=head1 COPYRIGHT
114
115Copyright 2002-2019 The OpenSSL Project Authors. All Rights Reserved.
116
117Licensed under the OpenSSL license (the "License").  You may not use
118this file except in compliance with the License.  You can obtain a copy
119in the file LICENSE in the source distribution or at
120L<https://www.openssl.org/source/license.html>.
121
122=cut
123