Tss2_Tcti_Mssim_Init - Man Page

Initialization function for the Microsoft TPM simulator TCTI library.


#include <tcti/tcti_mssim.h>

TSS2_RC Tss2_Tcti_Mssim_Init (TSS2_TCTI_CONTEXT *tctiContext, size_t *contextSize, const char *conf);

The Tss2_Tcti_Mssim_Init() function initializes a TCTI context used to communicate with the Microsoft TPM2 simulator.


Tss2_Tcti_Mssim_Init() attempts to initialize a caller allocated tcti_context of size size using caller provided configuration string conf . Since the tcti_context must be a caller allocated buffer, the caller needs to know the buffer 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 must then allocate a buffer of this size (or larger) and call Tss2_Tcti_Mssim_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_Mssim_Init() function in the section titled Example.

The conf parameter is a C string used to configure the TCTI context. This configuration string is a series of key / value pairs that specify the host and port used to connect to an instance of the Microsoft TPM2 simulator. The keys and values are separated by the '=' character, while each key / value pair is separated by the ',' character.

The only keys supported in the conf string are host and port. The host may be an IPv4 address, an IPv6 address, or a host name. The port must be a valid uint16_t in string form. If a NULL conf string is provided by the caller then the default of "host=localhost,port=2321" is used. If either host or port are omitted then their respective default value will be used.

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 Microsoft TPM simulator. 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” 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_Mssim_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 both the tcti_context and the size parameters are NULL, or if the config parameter is NULL.


TCTI initialization fragment:

#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <tcti/tcti_mssim.h>

TSS2_RC rc;
TSS2_TCTI_CONTEXT *tcti_context;
size_t size;
const char *conf = "host=localhost,port=2321"

rc = Tss2_Tcti_Mssim_Init (NULL, &size, NULL);
if (rc != TSS2_RC_SUCCESS) {
    fprintf (stderr, "Failed to get allocation size for mssim 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_Mssim_Init (&tcti_context, &size, conf);
if (rc != TSS2_RC_SUCCESS) {
    fprintf (stderr, "Failed to initialize mssim TCTI context: "
             "0x%" PRIx32 "0, rc);
    free (tcti_context);
    exit (EXIT_FAILURE);


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

See Also

Tss2_Tcti_Device_Init(3), Tss2_Tcti_Socket_Init(3), Tss2_TctiLdr_Initialize(3), Tss2_TctiLdr_Finalize(3), tcti-device(7), tcti-socket(7), tcti-tabrmd(7), tpm2-abrmd(8)


This page is part of release 3.0.2 of Open Source implementation of the TCG TPM2 Software Stack (TSS2). A description of the project, information about reporting bugs, and the latest version of this page can be found at https://github.com/tpm2-software/tpm2-tss/.


JUNE 2017 TPM2 Software Stack