xref: /freebsd/secure/lib/libcrypto/man/man3/OBJ_nid2obj.3 (revision ec0ea6efa1ad229d75c394c1a9b9cac33af2b1d3)
Automatically generated by Pod::Man 4.14 (Pod::Simple 3.43)

Standard preamble:
========================================================================
..
..
.. Set up some character translations and predefined strings. \*(-- will
give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
double quote, and \*(R" will give a right double quote. \*(C+ will
give a nicer C++. Capital omega is used to do unbreakable dashes and
therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
nothing in troff, for use with C<>.
.tr \(*W- . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\}
Escape single quotes in literal strings from groff's Unicode transform.

If the F register is >0, we'll generate index entries on stderr for
titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
entries marked with X<> in POD. Of course, you'll have to process the
output yourself in some meaningful fashion.

Avoid warning from groff about undefined register 'F'.
.. .nr rF 0 . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF
Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
Fear. Run. Save yourself. No user-serviceable parts.
. \" fudge factors for nroff and troff . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] .\} . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents . \" corrections for vroff . \" for low resolution devices (crt and lpr) \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} ========================================================================

Title "OBJ_NID2OBJ 3"
OBJ_NID2OBJ 3 "2021-12-14" "1.1.1m" "OpenSSL"
For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
"NAME"
i2t_ASN1_OBJECT, OBJ_length, OBJ_get0_data, OBJ_nid2obj, OBJ_nid2ln, OBJ_nid2sn, OBJ_obj2nid, OBJ_txt2nid, OBJ_ln2nid, OBJ_sn2nid, OBJ_cmp, OBJ_dup, OBJ_txt2obj, OBJ_obj2txt, OBJ_create, OBJ_cleanup \- ASN1 object utility functions
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1 #include <openssl/objects.h> \& ASN1_OBJECT *OBJ_nid2obj(int n); const char *OBJ_nid2ln(int n); const char *OBJ_nid2sn(int n); \& int OBJ_obj2nid(const ASN1_OBJECT *o); int OBJ_ln2nid(const char *ln); int OBJ_sn2nid(const char *sn); \& int OBJ_txt2nid(const char *s); \& ASN1_OBJECT *OBJ_txt2obj(const char *s, int no_name); int OBJ_obj2txt(char *buf, int buf_len, const ASN1_OBJECT *a, int no_name); \& int i2t_ASN1_OBJECT(char *buf, int buf_len, const ASN1_OBJECT *a); \& int OBJ_cmp(const ASN1_OBJECT *a, const ASN1_OBJECT *b); ASN1_OBJECT *OBJ_dup(const ASN1_OBJECT *o); \& int OBJ_create(const char *oid, const char *sn, const char *ln); \& size_t OBJ_length(const ASN1_OBJECT *obj); const unsigned char *OBJ_get0_data(const ASN1_OBJECT *obj); .Ve

Deprecated:

.Vb 3 #if OPENSSL_API_COMPAT < 0x10100000L void OBJ_cleanup(void) #endif .Ve

"DESCRIPTION"
Header "DESCRIPTION" The \s-1ASN1\s0 object utility functions process \s-1ASN1_OBJECT\s0 structures which are a representation of the \s-1ASN1 OBJECT IDENTIFIER\s0 (\s-1OID\s0) type. For convenience, OIDs are usually represented in source code as numeric identifiers, or \s-1NID\s0s. OpenSSL has an internal table of OIDs that are generated when the library is built, and their corresponding NIDs are available as defined constants. For the functions below, application code should treat all returned values \*(-- OIDs, NIDs, or names \*(-- as constants.

\fBOBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the \s-1NID\s0 n to an \s-1ASN1_OBJECT\s0 structure, its long name and its short name respectively, or \s-1NULL\s0 if an error occurred.

\fBOBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() return the corresponding \s-1NID\s0 for the object o, the long name <ln> or the short name <sn> respectively or NID_undef if an error occurred.

\fBOBJ_txt2nid() returns \s-1NID\s0 corresponding to text string s. s can be a long name, a short name or the numerical representation of an object.

\fBOBJ_txt2obj() converts the text string s into an \s-1ASN1_OBJECT\s0 structure. If no_name is 0 then long names and short names will be interpreted as well as numerical forms. If no_name is 1 only the numerical form is acceptable.

\fBOBJ_obj2txt() converts the \s-1ASN1_OBJECT\s0 a into a textual representation. The representation is written as a null terminated string to buf at most buf_len bytes are written, truncating the result if necessary. The total amount of space required is returned. If no_name is 0 then if the object has a long or short name then that will be used, otherwise the numerical form will be used. If no_name is 1 then the numerical form will always be used.

\fBi2t_ASN1_OBJECT() is the same as OBJ_obj2txt() with the no_name set to zero.

\fBOBJ_cmp() compares a to b. If the two are identical 0 is returned.

\fBOBJ_dup() returns a copy of o.

\fBOBJ_create() adds a new object to the internal table. oid is the numerical form of the object, sn the short name and ln the long name. A new \s-1NID\s0 is returned for the created object in case of success and NID_undef in case of failure.

\fBOBJ_length() returns the size of the content octets of obj.

\fBOBJ_get0_data() returns a pointer to the content octets of obj. The returned pointer is an internal pointer which must not be freed.

\fBOBJ_cleanup() releases any resources allocated by creating new objects.

"NOTES"
Header "NOTES" Objects in OpenSSL can have a short name, a long name and a numerical identifier (\s-1NID\s0) associated with them. A standard set of objects is represented in an internal table. The appropriate values are defined in the header file objects.h.

For example the \s-1OID\s0 for commonName has the following definitions:

.Vb 3 #define SN_commonName "CN" #define LN_commonName "commonName" #define NID_commonName 13 .Ve

New objects can be added by calling OBJ_create().

Table objects have certain advantages over other objects: for example their NIDs can be used in a C language switch statement. They are also static constant structures which are shared: that is there is only a single constant structure for each table object.

Objects which are not in the table have the \s-1NID\s0 value NID_undef.

Objects do not need to be in the internal tables to be processed, the functions OBJ_txt2obj() and OBJ_obj2txt() can process the numerical form of an \s-1OID.\s0

Some objects are used to represent algorithms which do not have a corresponding \s-1ASN.1 OBJECT IDENTIFIER\s0 encoding (for example no \s-1OID\s0 currently exists for a particular algorithm). As a result they cannot be encoded or decoded as part of \s-1ASN.1\s0 structures. Applications can determine if there is a corresponding \s-1OBJECT IDENTIFIER\s0 by checking OBJ_length() is not zero.

These functions cannot return const because an \s-1ASN1_OBJECT\s0 can represent both an internal, constant, \s-1OID\s0 and a dynamically-created one. The latter cannot be constant because it needs to be freed after use.

"RETURN VALUES"
Header "RETURN VALUES" \fBOBJ_nid2obj() returns an \s-1ASN1_OBJECT\s0 structure or \s-1NULL\s0 is an error occurred.

\fBOBJ_nid2ln() and OBJ_nid2sn() returns a valid string or \s-1NULL\s0 on error.

\fBOBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() and OBJ_txt2nid() return a \s-1NID\s0 or NID_undef on error.

"EXAMPLES"
Header "EXAMPLES" Create an object for commonName:

.Vb 1 ASN1_OBJECT *o = OBJ_nid2obj(NID_commonName); .Ve

Check if an object is commonName

.Vb 2 if (OBJ_obj2nid(obj) == NID_commonName) /* Do something */ .Ve

Create a new \s-1NID\s0 and initialize an object from it:

.Vb 2 int new_nid = OBJ_create("1.2.3.4", "NewOID", "New Object Identifier"); ASN1_OBJECT *obj = OBJ_nid2obj(new_nid); .Ve

Create a new object directly:

.Vb 1 obj = OBJ_txt2obj("1.2.3.4", 1); .Ve

"BUGS"
Header "BUGS" \fBOBJ_obj2txt() is awkward and messy to use: it doesn't follow the convention of other OpenSSL functions where the buffer can be set to \s-1NULL\s0 to determine the amount of data that should be written. Instead buf must point to a valid buffer and buf_len should be set to a positive value. A buffer length of 80 should be more than enough to handle any \s-1OID\s0 encountered in practice.
"SEE ALSO"
Header "SEE ALSO" \fBERR_get_error\|(3)
"HISTORY"
Header "HISTORY" \fBOBJ_cleanup() was deprecated in OpenSSL 1.1.0 by OPENSSL_init_crypto\|(3) and should not be used.
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2002-2021 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.