Tss2_Tcti_Tabrmd_Init - Man Page

Initialization function for the tpm2-abrmd TCTI library.


The Tss2_Tcti_Tabrmd_Init() function is used to initialize a TCTI context for communication with the tpm2-abrmd(8).

#include <tcti/tcti-tabrmd.h>

TSS2_RC Tss2_Tcti_Tabrmd_Init (TSS2_TCTI_CONTEXT *tcti_context, size_t *size, const char *conf);


Tss2_Tcti_Tabrmd_Init() attempts to initialize a caller allocated tcti_context of size size with configuration specified in the configuration string conf. . Since the tcti_context must be a caller allocated buffer, the caller needs to know the size required by the TCTI library. The minimum size of this context can be discovered by providing NULL for the tcti_context and a non- NULL size parameter. The initialization function will then populate the size parameter with the minimum size of the tcti_context buffer. The caller my then allocate a buffer of this size (or larger) and call tss2_Tcti_Tabrmd_Init () again providing the newly allocated tcti_context and the size of this context in the size parameter. This pattern is common to all TCTI initialization functions. We provide an example of this pattern using the Tss2_Tcti_Tabrmd_Init() function in the section titled Example.

The conf parameter is a string of key / value pairs describing the desired connection properties for the TCTI. If the caller provides a NULL conf string then defaults that correspond to the defaults for the tpm2-abrmd (8) will be used. This is the same as providing the conf string: "bus_name=com.intel.tss2.Tabrmd,bus_type=system". Keys and values are separated by the '=' character while each key / value pair is separated by the ',' character. The supported keys and values are:

Once initialized, the TCTI context returned exposes the Trusted Computing Group (TCG) defined API for the lowest level communication with the TPM. Using this API the caller can exchange (send / receive) TPM2 command and response buffers with the tpm2-abrmd (8). In nearly all cases however, the caller will initialize a context using this function before passing the context to a higher level API like the System API (SAPI), and then never touch it again.

For a more thorough discussion of the TCTI API see the “TSS System Level API and TPM Command Transmission Interface Specification” specification as published by the TCG: https://trustedcomputinggroup.org/tss-system-level-api-tpm-command-transmission-interface-specification/

Return Value

A successful call to Tss2_Tcti_Tabrmd_Init() will return TSS2_RC_SUCCESS. An unsuccessful call will produce a response code described in section Errors.


TSS2_TCTI_RC_BAD_VALUE is returned if the size parameter is NULL.

TSS2_TCTI_RC_NO_CONNECTION is returned when communication with the tpm2-abrmd (8) fails.

TSS2_TCTI_RC_GENERAL_FAILURE is returned for all other errors.


#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <tcti/tcti-tabrmd.h>

TSS2_RC rc;
TSS2_TCTI_CONTEXT *tcti_context;
size_t size;

rc = tss2_tcti_tabrmd_init (NULL, &size, NULL,
if (rc != TSS2_RC_SUCCESS) {
    fprintf (stderr, "Failed to get allocation size for tabrmd TCTI "
             " context: 0x%" PRIx32 "0, rc);
    exit (EXIT_FAILURE);
tcti_context = calloc (1, size);
if (tcti_context == NULL) {
    fprintf (stderr, "Allocation for TCTI context failed: %s0,
             strerror (errno));
    exit (EXIT_FAILURE);
rc = tss2_tcti_tabrmd_init (tcti_context, &size, NULL);
if (rc != TSS2_RC_SUCCESS) {
    fprintf (stderr, "Failed to initialize tabrmd TCTI context: "
             "0x%" PRIx32 "0, rc);
    free (tcti_context);
    exit (EXIT_FAILURE);


Philip Tricca <philip.b.tricca@intel.com>

See Also

tcti-tabrmd(7), tpm2-abrmd(8)


This page is part of the 2.3.3 release of Intel's TPM2 Access Broker & Resource Management Daemon. A description of the project, information about reporting bugs, and the latest version of this page can be found at https://github.com/01org/tpm2-abrmd/.


APRIL 2018 Intel TPM2 Software Stack