NAME

       Tss2_Tcti_Device_init - Initialization function for the device TCTI library.

SYNOPSIS

       #include <tcti/tcti_device.h>

       TSS2_RC  Tss2_Tcti_Device_Init  (TSS2_TCTI_CONTEXT  *tctiContext, size_t *size, const char
       *conf);

       The Tss2_Tcti_Device_Init() function initializes a TCTI context used to  communicate  with
       the TPM device driver.

DESCRIPTION

       Tss2_Tcti_Device_Init() attempts to initialize a caller allocated tctiContext of size size
       . Since the tctiContext 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 tctiContext and a non-  NULL  size  parameter.  The  initialization
       function  will  then  populate the size parameter with the minimum size of the tctiContext
       buffer. The caller must then  allocate  a  buffer  of  this  size  (or  larger)  and  call
       Tss2_Tcti_Device_Init  ()  again providing the newly allocated tctiContext 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_Device_Init()
       function in the section titled EXAMPLE.

       The conf parameter is a C string. If this string is NULL  then  the  library  will  use  a
       default  configuration  string  for  the  caller.  Alternatively, the caller may provide a
       configuration string that must contain the path to the device  node  exposed  by  the  TPM
       device driver.

       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 TPM device
       driver. 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.

       TCG TSS 2.0 TPM Command Transmission Interface (TCTI) API Specification

       For a more thorough discussion  of  the  TCTI  API  see  the  “TCG  TSS  2.0  TPM  Command
       Transmission   Interface   (TCTI)   API   Specification”   as   published   by   the  TCG:
       https://trustedcomputinggroup.org/wp-content/uploads/TSS_TCTI_Version-1.0_Revision-05_Review_END030918.pdf

RETURN VALUE

       A successful call to Tss2_Tcti_Device_Init() 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  any  parameters   contain   unexpected   values.
       TSS2_TCTI_RC_BAD_REFERENCE is returned if any parameters are NULL when they should not be.
       TSS2_TCTI_RC_BAD_CONTEXT  is  returned  if  the  size  of  the  provided  tctiContext   is
       insufficient.

EXAMPLE

       TCTI initialization fragment:

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

       TSS2_RC rc;
       TSS2_TCTI_CONTEXT *tcti_context;
       size_t size;
       char *conf = "/dev/tpm0",

       rc = Tss2_Tcti_Device_Init (NULL, &size, NULL);
       if (rc != TSS2_RC_SUCCESS) {
           fprintf (stderr, "Failed to get allocation size for device 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_Device_Init (&tcti_context, &size, &conf);
       if (rc != TSS2_RC_SUCCESS) {
           fprintf (stderr, "Failed to initialize device TCTI context: "
                    "0x%" PRIx32 "0, rc);
           free (tcti_context);
           exit (EXIT_FAILURE);
       }
       exit (EXIT_SUCCESS);

AUTHOR

       TPM2 Software Project <https://github.com/tpm2-software/tpm2-tss>

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)

COLOPHON

       This page is part of release 4.0.1 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/.