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1 | =pod | ||
2 | |||
3 | =head1 NAME | ||
4 | |||
5 | OBJ_nid2obj, OBJ_nid2ln, OBJ_nid2sn, OBJ_obj2nid, OBJ_txt2nid, OBJ_ln2nid, OBJ_sn2nid, | ||
6 | OBJ_cmp, OBJ_dup, OBJ_txt2obj, OBJ_obj2txt, OBJ_create, OBJ_cleanup - ASN1 object utility | ||
7 | functions | ||
8 | |||
9 | =head1 SYNOPSIS | ||
10 | |||
11 | #include <openssl/objects.h> | ||
12 | |||
13 | ASN1_OBJECT * OBJ_nid2obj(int n); | ||
14 | const char * OBJ_nid2ln(int n); | ||
15 | const char * OBJ_nid2sn(int n); | ||
16 | |||
17 | int OBJ_obj2nid(const ASN1_OBJECT *o); | ||
18 | int OBJ_ln2nid(const char *ln); | ||
19 | int OBJ_sn2nid(const char *sn); | ||
20 | |||
21 | int OBJ_txt2nid(const char *s); | ||
22 | |||
23 | ASN1_OBJECT * OBJ_txt2obj(const char *s, int no_name); | ||
24 | int OBJ_obj2txt(char *buf, int buf_len, const ASN1_OBJECT *a, int no_name); | ||
25 | |||
26 | int OBJ_cmp(const ASN1_OBJECT *a,const ASN1_OBJECT *b); | ||
27 | ASN1_OBJECT * OBJ_dup(const ASN1_OBJECT *o); | ||
28 | |||
29 | int OBJ_create(const char *oid,const char *sn,const char *ln); | ||
30 | void OBJ_cleanup(void); | ||
31 | |||
32 | =head1 DESCRIPTION | ||
33 | |||
34 | The ASN1 object utility functions process ASN1_OBJECT structures which are | ||
35 | a representation of the ASN1 OBJECT IDENTIFIER (OID) type. | ||
36 | |||
37 | OBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the NID B<n> to | ||
38 | an ASN1_OBJECT structure, its long name and its short name respectively, | ||
39 | or B<NULL> is an error occurred. | ||
40 | |||
41 | OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() return the corresponding NID | ||
42 | for the object B<o>, the long name <ln> or the short name <sn> respectively | ||
43 | or NID_undef if an error occurred. | ||
44 | |||
45 | OBJ_txt2nid() returns NID corresponding to text string <s>. B<s> can be | ||
46 | a long name, a short name or the numerical respresentation of an object. | ||
47 | |||
48 | OBJ_txt2obj() converts the text string B<s> into an ASN1_OBJECT structure. | ||
49 | If B<no_name> is 0 then long names and short names will be interpreted | ||
50 | as well as numerical forms. If B<no_name> is 1 only the numerical form | ||
51 | is acceptable. | ||
52 | |||
53 | OBJ_obj2txt() converts the B<ASN1_OBJECT> B<a> into a textual representation. | ||
54 | The representation is written as a null terminated string to B<buf> | ||
55 | at most B<buf_len> bytes are written, truncating the result if necessary. | ||
56 | The total amount of space required is returned. If B<no_name> is 0 then | ||
57 | if the object has a long or short name then that will be used, otherwise | ||
58 | the numerical form will be used. If B<no_name> is 1 then the numerical | ||
59 | form will always be used. | ||
60 | |||
61 | OBJ_cmp() compares B<a> to B<b>. If the two are identical 0 is returned. | ||
62 | |||
63 | OBJ_dup() returns a copy of B<o>. | ||
64 | |||
65 | OBJ_create() adds a new object to the internal table. B<oid> is the | ||
66 | numerical form of the object, B<sn> the short name and B<ln> the | ||
67 | long name. A new NID is returned for the created object. | ||
68 | |||
69 | OBJ_cleanup() cleans up OpenSSLs internal object table: this should | ||
70 | be called before an application exits if any new objects were added | ||
71 | using OBJ_create(). | ||
72 | |||
73 | =head1 NOTES | ||
74 | |||
75 | Objects in OpenSSL can have a short name, a long name and a numerical | ||
76 | identifier (NID) associated with them. A standard set of objects is | ||
77 | represented in an internal table. The appropriate values are defined | ||
78 | in the header file B<objects.h>. | ||
79 | |||
80 | For example the OID for commonName has the following definitions: | ||
81 | |||
82 | #define SN_commonName "CN" | ||
83 | #define LN_commonName "commonName" | ||
84 | #define NID_commonName 13 | ||
85 | |||
86 | New objects can be added by calling OBJ_create(). | ||
87 | |||
88 | Table objects have certain advantages over other objects: for example | ||
89 | their NIDs can be used in a C language switch statement. They are | ||
90 | also static constant structures which are shared: that is there | ||
91 | is only a single constant structure for each table object. | ||
92 | |||
93 | Objects which are not in the table have the NID value NID_undef. | ||
94 | |||
95 | Objects do not need to be in the internal tables to be processed, | ||
96 | the functions OBJ_txt2obj() and OBJ_obj2txt() can process the numerical | ||
97 | form of an OID. | ||
98 | |||
99 | =head1 EXAMPLES | ||
100 | |||
101 | Create an object for B<commonName>: | ||
102 | |||
103 | ASN1_OBJECT *o; | ||
104 | o = OBJ_nid2obj(NID_commonName); | ||
105 | |||
106 | Check if an object is B<commonName> | ||
107 | |||
108 | if (OBJ_obj2nid(obj) == NID_commonName) | ||
109 | /* Do something */ | ||
110 | |||
111 | Create a new NID and initialize an object from it: | ||
112 | |||
113 | int new_nid; | ||
114 | ASN1_OBJECT *obj; | ||
115 | new_nid = OBJ_create("1.2.3.4", "NewOID", "New Object Identifier"); | ||
116 | |||
117 | obj = OBJ_nid2obj(new_nid); | ||
118 | |||
119 | Create a new object directly: | ||
120 | |||
121 | obj = OBJ_txt2obj("1.2.3.4", 1); | ||
122 | |||
123 | =head1 BUGS | ||
124 | |||
125 | OBJ_obj2txt() is awkward and messy to use: it doesn't follow the | ||
126 | convention of other OpenSSL functions where the buffer can be set | ||
127 | to B<NULL> to determine the amount of data that should be written. | ||
128 | Instead B<buf> must point to a valid buffer and B<buf_len> should | ||
129 | be set to a positive value. A buffer length of 80 should be more | ||
130 | than enough to handle any OID encountered in practice. | ||
131 | |||
132 | =head1 RETURN VALUES | ||
133 | |||
134 | OBJ_nid2obj() returns an B<ASN1_OBJECT> structure or B<NULL> is an | ||
135 | error occurred. | ||
136 | |||
137 | OBJ_nid2ln() and OBJ_nid2sn() returns a valid string or B<NULL> | ||
138 | on error. | ||
139 | |||
140 | OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() and OBJ_txt2nid() return | ||
141 | a NID or B<NID_undef> on error. | ||
142 | |||
143 | =head1 SEE ALSO | ||
144 | |||
145 | L<ERR_get_error(3)|ERR_get_error(3)> | ||
146 | |||
147 | =head1 HISTORY | ||
148 | |||
149 | TBA | ||
150 | |||
151 | =cut | ||