.\" $OpenBSD: X509at_add1_attr.3,v 1.5 2021/10/26 12:56:48 schwarze Exp $
.\"
.\" Copyright (c) 2021 Ingo Schwarze <schwarze@openbsd.org>
.\"
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.Dd $Mdocdate: October 26 2021 $
.Dt X509AT_ADD1_ATTR 3
.Os
.Sh NAME
.Nm X509at_add1_attr ,
.Nm X509at_add1_attr_by_OBJ ,
.Nm X509at_add1_attr_by_NID ,
.Nm X509at_add1_attr_by_txt ,
.Nm X509at_delete_attr
.Nd change an array of X.501 Attribute objects
.Sh SYNOPSIS
.In openssl/x509.h
.Ft STACK_OF(X509_ATTRIBUTE) *
.Fo X509at_add1_attr
.Fa "STACK_OF(X509_ATTRIBUTE) **pattrs"
.Fa "X509_ATTRIBUTE *attr"
.Fc
.Ft STACK_OF(X509_ATTRIBUTE) *
.Fo X509at_add1_attr_by_OBJ
.Fa "STACK_OF(X509_ATTRIBUTE) **pattrs"
.Fa "const ASN1_OBJECT *obj"
.Fa "int type"
.Fa "const unsigned char *data"
.Fa "int len"
.Fc
.Ft STACK_OF(X509_ATTRIBUTE) *
.Fo X509at_add1_attr_by_NID
.Fa "STACK_OF(X509_ATTRIBUTE) **pattrs"
.Fa "int nid"
.Fa "int type"
.Fa "const unsigned char *data"
.Fa "int len"
.Fc
.Ft STACK_OF(X509_ATTRIBUTE) *
.Fo X509at_add1_attr_by_txt
.Fa "STACK_OF(X509_ATTRIBUTE) **pattrs"
.Fa "const char *name"
.Fa "int type"
.Fa "const unsigned char *data"
.Fa "int len"
.Fc
.Ft X509_ATTRIBUTE *
.Fo X509at_delete_attr
.Fa "STACK_OF(X509_ATTRIBUTE) *attrs"
.Fa "int index"
.Fc
.Sh DESCRIPTION
.Fn X509at_add1_attr
appends a deep copy of
.Fa attr
to the end of
.Pf ** Fa pattrs .
If
.Pf * Fa pattrs
is
.Dv NULL ,
a new array is allocated, and in case of success,
a pointer to it is assigned to
.Pf * Fa pattrs .
.Pp
.Fn X509at_add1_attr_by_OBJ ,
.Fn X509at_add1_attr_by_NID ,
and
.Fn X509at_add1_attr_by_txt
create a new X.501 Attribute object using
.Xr X509_ATTRIBUTE_create_by_OBJ 3 ,
.Xr X509_ATTRIBUTE_create_by_NID 3 ,
or
.Xr X509_ATTRIBUTE_create_by_txt 3 ,
respectively, and append it to
.Pf ** Fa pattrs
using
.Fn X509at_add1_attr .
.Pp
.Fn X509at_delete_attr
deletes the element with the zero-based
.Fa index
from the array
.Pf * Fa attrs .
.Sh RETURN VALUES
.Fn X509at_add1_attr ,
.Fn X509at_add1_attr_by_OBJ ,
.Fn X509at_add1_attr_by_NID ,
and
.Fn X509at_add1_attr_by_txt
return a pointer to the modified or new array or
.Dv NULL
if the
.Fa pattrs
argument is
.Dv NULL
or if creating or copying the X.501 Attribute object
or memory allocation fails.
.Pp
.Fn X509at_delete_attr
returns the deleted element or
.Dv NULL
if
.Fa attrs
is
.Dv NULL
or if the requested
.Fa index
is negative or greater than or equal to the number of objects in
.Pf * Fa attrs .
.Sh SEE ALSO
.Xr EVP_PKEY_add1_attr 3 ,
.Xr OBJ_nid2obj 3 ,
.Xr PKCS8_pkey_add1_attr_by_NID 3 ,
.Xr STACK_OF 3 ,
.Xr X509_ATTRIBUTE_create_by_OBJ 3 ,
.Xr X509_ATTRIBUTE_new 3 ,
.Xr X509_REQ_add1_attr 3 ,
.Xr X509at_get_attr 3
.Sh HISTORY
These functions first appeared in OpenSSL 0.9.5
and have been available since
.Ox 2.7 .