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Command: X509_NAME_get_index_by_NID | Section: 3 | Source: OpenBSD | File: X509_NAME_get_index_by_NID.3
X509_NAME_GET_INDEX_BY_NID(3) FreeBSD Library Functions Manual
NAME
X509_NAME_get_index_by_NID, X509_NAME_get_index_by_OBJ,
X509_NAME_entry_count, X509_NAME_get_entry, X509_NAME_get_text_by_NID,
X509_NAME_get_text_by_OBJ - X509_NAME lookup and enumeration functions
SYNOPSIS
#include <openssl/x509.h>
int
X509_NAME_get_index_by_NID(const X509_NAME *name, int nid, int lastpos);
int
X509_NAME_get_index_by_OBJ(const X509_NAME *name, const ASN1_OBJECT *obj,
int lastpos);
int
X509_NAME_entry_count(const X509_NAME *name);
X509_NAME_ENTRY *
X509_NAME_get_entry(const X509_NAME *name, int loc);
int
X509_NAME_get_text_by_NID(X509_NAME *name, int nid, char *buf, int len);
int
X509_NAME_get_text_by_OBJ(X509_NAME *name, const ASN1_OBJECT *obj,
char *buf, int len);
DESCRIPTION
These functions allow an X509_NAME structure to be examined. The
X509_NAME structure is the same as the ASN.1 Name type defined in RFC
2459 (and elsewhere) and used, for example, in certificate subject and
issuer names.
X509_NAME_get_index_by_NID() and X509_NAME_get_index_by_OBJ() retrieve
the next index matching nid or obj after lastpos. lastpos should
initially be set to -1.
X509_NAME_get_entry() retrieves the X509_NAME_ENTRY from name
corresponding to index loc. Acceptable values for loc run from 0 to
X509_NAME_entry_count(name) - 1.
X509_NAME_get_text_by_NID() and X509_NAME_get_text_by_OBJ() retrieve the
bytes encoded as UTF-8 from the first entry in name which matches nid or
obj. If buf is NULL, nothing is written, but the return value is
calculated as usual. If buf is not NULL, no more than len bytes will be
written and the text written to buf will be NUL terminated.
If len is not large enough to hold the NUL byte terminated UTF-8 encoding
of the text, or if the UTF-8 encoding of the text would contains a NUL
byte, no data will be written and the call will return failure.
All relevant NID_* and OBJ_* codes can be found in the
<openssl/objects.h> header file.
Applications which could pass invalid NIDs to
X509_NAME_get_index_by_NID() should check for the return value of -2.
Alternatively the NID validity can be determined first by checking that
OBJ_nid2obj(nid) is not NULL.
RETURN VALUES
X509_NAME_get_index_by_NID() returns the index of the next matching
entry, -1 if not found, or -2 if the nid does not correspond to a valid
OID.
X509_NAME_get_index_by_OBJ() returns the index of the next matching entry
or -1 if not found.
X509_NAME_entry_count() returns the total number of entries in name.
X509_NAME_get_entry() returns an internal pointer which must not be freed
by the caller or NULL if the index is invalid.
X509_NAME_get_text_by_NID() and X509_NAME_get_text_by_OBJ() return the
length of the output UTF-8 string written, not counting the terminating
NUL, or -1 in the case of an error or no match being found.
In some cases of failure of X509_NAME_get_index_by_NID() and
X509_NAME_get_text_by_NID(), the reason can be determined with
ERR_get_error(3).
EXAMPLES
Process all entries:
int i;
X509_NAME_ENTRY *e;
for (i = 0; i < X509_NAME_entry_count(nm); i++) {
e = X509_NAME_get_entry(nm, i);
/* Do something with e */
}
Process all commonName entries:
int lastpos = -1;
X509_NAME_ENTRY *e;
for (;;) {
lastpos = X509_NAME_get_index_by_NID(nm, NID_commonName, lastpos);
if (lastpos == -1)
break;
e = X509_NAME_get_entry(nm, lastpos);
/* Do something with e */
}
SEE ALSO
d2i_X509_NAME(3), X509_NAME_ENTRY_get_object(3), X509_NAME_new(3)
HISTORY
These functions first appeared in SSLeay 0.8.0 and have been available
since OpenBSD 2.4.
CAVEATS
X509_NAME_get_text_by_NID() and X509_NAME_get_text_by_OBJ() are legacy
functions which have various limitations which make them of minimal use
in practice. They can only find the first matching entry and will copy
the contents of the field verbatim: this can be highly confusing if the
target is a multicharacter string type like a BMPString or a UTF8String.
For a more general solution, X509_NAME_get_index_by_NID() or
X509_NAME_get_index_by_OBJ() should be used, followed by
X509_NAME_get_entry() on any matching indices and then the various
X509_NAME_ENTRY utility functions on the result.
FreeBSD 14.1-RELEASE-p8 May 29, 2023 FreeBSD 14.1-RELEASE-p8