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, CMS_encrypt) 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 2008-2019 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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>.