X509_NAME_get_index_by_NID.pod revision 296465 
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,ASN1_OBJECT *obj, int lastpos);
15
16 int X509_NAME_entry_count(X509_NAME *name);
17 X509_NAME_ENTRY *X509_NAME_get_entry(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, 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() are
52legacy functions which have various limitations which make them
53of minimal use in practice. They can only find the first matching
54entry and will copy the contents of the field verbatim: this can
55be highly confusing if the target is a muticharacter string type
56like a BMPString or a UTF8String.
57
58For a more general solution X509_NAME_get_index_by_NID() or
59X509_NAME_get_index_by_OBJ() should be used followed by
60X509_NAME_get_entry() on any matching indices and then the
61various B<X509_NAME_ENTRY> utility functions on the result.
62
63Applications which could pass invalid NIDs to X509_NAME_get_index_by_NID()
64should check for the return value of -2. Alternatively the NID validity
65can be determined first by checking OBJ_nid2obj(nid) is not NULL.
66
67=head1 EXAMPLES
68
69Process all entries:
70
71 int i;
72 X509_NAME_ENTRY *e;
73
74 for (i = 0; i < X509_NAME_entry_count(nm); i++)
75	{
76	e = X509_NAME_get_entry(nm, i);
77	/* Do something with e */
78	}
79
80Process all commonName entries:
81
82 int loc;
83 X509_NAME_ENTRY *e;
84
85 loc = -1;
86 for (;;)
87	{
88	lastpos = X509_NAME_get_index_by_NID(nm, NID_commonName, lastpos);
89	if (lastpos == -1)
90		break;
91	e = X509_NAME_get_entry(nm, lastpos);
92	/* Do something with e */
93	}
94
95=head1 RETURN VALUES
96
97X509_NAME_get_index_by_NID() and X509_NAME_get_index_by_OBJ()
98return the index of the next matching entry or -1 if not found.
99X509_NAME_get_index_by_NID() can also return -2 if the supplied
100NID is invalid.
101
102X509_NAME_entry_count() returns the total number of entries.
103
104X509_NAME_get_entry() returns an B<X509_NAME> pointer to the
105requested entry or B<NULL> if the index is invalid.
106
107=head1 SEE ALSO
108
109L<ERR_get_error(3)|ERR_get_error(3)>, L<d2i_X509_NAME(3)|d2i_X509_NAME(3)>
110
111=head1 HISTORY
112
113TBA
114
115=cut
116