NAME

       CMS_get0_type, CMS_set1_eContentType, CMS_get0_eContentType, CMS_get0_content - get and
       set CMS content types and content

SYNOPSIS

        #include <openssl/cms.h>

        const ASN1_OBJECT *CMS_get0_type(const CMS_ContentInfo *cms);
        int CMS_set1_eContentType(CMS_ContentInfo *cms, const ASN1_OBJECT *oid);
        const ASN1_OBJECT *CMS_get0_eContentType(CMS_ContentInfo *cms);
        ASN1_OCTET_STRING **CMS_get0_content(CMS_ContentInfo *cms);

DESCRIPTION

       CMS_get0_type() returns the content type of a CMS_ContentInfo structure as an ASN1_OBJECT
       pointer. An application can then decide how to process the CMS_ContentInfo structure based
       on this value.

       CMS_set1_eContentType() sets the embedded content type of a CMS_ContentInfo structure. It
       should be called with CMS functions (such as CMS_sign(3), CMS_encrypt(3)) with the
       CMS_PARTIAL flag and before the structure is finalised, otherwise the results are
       undefined.

       ASN1_OBJECT *CMS_get0_eContentType() returns a pointer to the embedded content type.

       CMS_get0_content() returns a pointer to the ASN1_OCTET_STRING pointer containing the
       embedded content.

NOTES

       As the 0 implies CMS_get0_type(), CMS_get0_eContentType() and CMS_get0_content() return
       internal pointers which should not be freed up.  CMS_set1_eContentType() copies the
       supplied OID and it should be freed up after use.

       The ASN1_OBJECT values returned can be converted to an integer NID value using
       OBJ_obj2nid(). For the currently supported content types the following values are
       returned:

        NID_pkcs7_data
        NID_pkcs7_signed
        NID_pkcs7_digest
        NID_id_smime_ct_compressedData:
        NID_pkcs7_encrypted
        NID_pkcs7_enveloped

       The return value of CMS_get0_content() is a pointer to the ASN1_OCTET_STRING content
       pointer. That means that for example:

        ASN1_OCTET_STRING **pconf = CMS_get0_content(cms);

       *pconf could be NULL if there is no embedded content. Applications can access, modify or
       create the embedded content in a CMS_ContentInfo structure using this function.
       Applications usually will not need to modify the embedded content as it is normally set by
       higher level functions.

RETURN VALUES

       CMS_get0_type() and CMS_get0_eContentType() return an ASN1_OBJECT structure.

       CMS_set1_eContentType() returns 1 for success or 0 if an error occurred.  The error can be
       obtained from ERR_get_error(3).

SEE ALSO

       ERR_get_error(3)

COPYRIGHT

       Copyright 2008-2016 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file except
       in compliance with the License.  You can obtain a copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.