NAME¶

tss2_tcti_tabrmd_init, tss2_tcti_tabrmd_init_full - Initialization functions for the tpm2-abrmd TCTI library.

SYNOPSIS¶

The tss2_tcti_tabrmd_init() and tss2_tcti_tabrmd_init_full() functions are 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);

TSS2_RC tss2_tcti_tabrmd_init_full (TSS2_TCTI_CONTEXT *tcti_context, size_t *size, GBusTypebus_type, const char*bus_name);

DESCRIPTION¶

tss2_tcti_tabrmd_init() attempts to initialize a caller allocated tcti_context of size size . 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 patterm 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.

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 respons buffers with the tpm2-abrmd (8). In nearly all cases however, the caller will initialize a context using this funnction 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/

tss2_tcti_tabrmd_init_full () behaves in the same way as tss2_tcti_tabrmd_init () but allows for greater flexibility through two additional parameters: The bus_type and bus_name parameters may be used to select which D-Bus bus type and name used to connect to an instance of the tpm2-abrmd (8) daemon.

RETURN VALUE¶

A successful call to tss2_tcti_tabrmd_init() and tss2_tcti_tabrmd_init_full() will return TSS2_RC_SUCCESS. An unsuccessful call will produce a response code described in section ERRORS.

ERRORS¶

TSS2_TCTI_RC_BAD_VALUE is returned if both the tcti_context and the size parameters are NULL, or the bus_name is NULL, or the bus_type is not a supported type (G_BUS_TYPE_SYSTEM OR G_BUS_TYPE_SESSION).

All errors caused by communication failures with the tpm2-abrmd (8) are treated as fatal errors and will call the calling application to terminate.

EXAMPLE¶

#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);
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);
if (rc != TSS2_RC_SUCCESS) {


    fprintf (stderr, "Failed to initialize tabrmd TCTI context: "


             "0x%" PRIx32 "0, rc);


    free (tcti_context);


    exit (EXIT_FAILURE);
}
exit (EXIT_SUCCESS);

AUTHOR¶

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

SEE ALSO¶

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

COLOPHON¶

This page is part of the 1.3.1 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/.