OBJ_nid2obj - OBJ_nid2obj, OBJ_nid2ln, OBJ_nid2sn, OBJ_obj2nid, OBJ_txt2nid, OBJ_ln2nid, OBJ_sn2nid, OBJ_cmp, OBJ_dup, OBJ_txt2obj, OBJ_obj2txt, ASN1 object utility functions
#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 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); void OBJ_cleanup(void);
OBJ_nid2obj(3openssl) OpenSSL OBJ_nid2obj(3openssl)
NAME
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
#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 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);
void OBJ_cleanup(void);
DESCRIPTION
The ASN1 object utility functions process ASN1_OBJECT structures which
are a representation of the ASN1 OBJECT IDENTIFIER (OID) type. For
convenience, OIDs are usually represented in source code as numeric
identifiers, or NIDs. 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.
OBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the NID n to an
ASN1_OBJECT structure, its long name and its short name respectively,
or NULL if an error occurred.
OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() return the corresponding NID
for the object o, the long name <ln> or the short name <sn>
respectively or NID_undef if an error occurred.
OBJ_txt2nid() returns NID corresponding to text string <s>. s can be a
long name, a short name or the numerical respresentation of an object.
OBJ_txt2obj() converts the text string s into an ASN1_OBJECT 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.
OBJ_obj2txt() converts the ASN1_OBJECT 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.
OBJ_cmp() compares a to b. If the two are identical 0 is returned.
OBJ_dup() returns a copy of o.
OBJ_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 NID is returned for the created object.
OBJ_cleanup() cleans up OpenSSLs internal object table: this should be
called before an application exits if any new objects were added using
OBJ_create().
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+--------------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+--------------------------+
|Availability | library/security/openssl |
+---------------+--------------------------+
|Stability | Pass-through uncommitted |
+---------------+--------------------------+
NOTES
Objects in OpenSSL can have a short name, a long name and a numerical
identifier (NID) 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 OID for commonName has the following definitions:
#define SN_commonName "CN"
#define LN_commonName "commonName"
#define NID_commonName 13
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 NID 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 OID.
Some objects are used to represent algorithms which do not have a
corresponding ASN.1 OBJECT IDENTIFIER encoding (for example no OID
currently exists for a particular algorithm). As a result they cannot
be encoded or decoded as part of ASN.1 structures. Applications can
determine if there is a corresponding OBJECT IDENTIFIER by checking
OBJ_length() is not zero.
These functions cannot return const because an ASN1_OBJECT can
represent both an internal, constant, OID and a dynamically-created
one. The latter cannot be constant because it needs to be freed after
use.
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from
https://www.openssl.org/source/openssl-1.0.2ze.tar.gz.
Further information about this software can be found on the open source
community website at https://www.openssl.org/.
EXAMPLES
Create an object for commonName:
ASN1_OBJECT *o;
o = OBJ_nid2obj(NID_commonName);
Check if an object is commonName
if (OBJ_obj2nid(obj) == NID_commonName)
/* Do something */
Create a new NID and initialize an object from it:
int new_nid;
ASN1_OBJECT *obj;
new_nid = OBJ_create("1.2.3.4", "NewOID", "New Object Identifier");
obj = OBJ_nid2obj(new_nid);
Create a new object directly:
obj = OBJ_txt2obj("1.2.3.4", 1);
BUGS
OBJ_obj2txt() is awkward and messy to use: it doesn't follow the
convention of other OpenSSL functions where the buffer can be set to
NULL 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 OID encountered in practice.
RETURN VALUES
OBJ_nid2obj() returns an ASN1_OBJECT structure or NULL is an error
occurred. It returns a pointer to an internal table and does not
allocate memory; ASN1_OBJECT_free() will have no effect.
OBJ_nid2ln() and OBJ_nid2sn() returns a valid string or NULL on error.
OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() and OBJ_txt2nid() return a
NID or NID_undef on error.
SEE ALSO
ERR_get_error(3)
HISTORY
TBA
1.0.2ze 2022-05-03 OBJ_nid2obj(3openssl)