NAME

       Tss2_Tcti_Cmd_Init - Initialization function for the Cmd TCTI library.

SYNOPSIS

       #include <tss2/tss2_tcti_cmd.h>

       TSS2_RC  Tss2_Tcti_Cmd_Init  (TSS2_TCTI_CONTEXT  *tctiContext,  size_t *contextSize, const
       char *conf);

       The Tss2_Tcti_Cmd_Init() function initializes a TCTI context used to  communicate  with  a
       subprocess specified in the conf string.  TCTI send and receives utilize the sub-process's
       stdio and stdout respectively.

DESCRIPTION

       Tss2_Tcti_Cmd_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_Cmd_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_Cmd_Init() function in the section titled EXAMPLE.

       The  conf  parameter  is a C string used to configure the TCTI context. This configuration
       string is the command used for popen(3). The conf string cannot be NULL for this TCTI.

       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 a  service  that  can
       excahnge  TPM2  command and response buffers. 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), Enhanced System API (ESAPI) or Feature API (FAPI) 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_Cmd_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 both the tcti_context and the  size  parameters  are
       NULL, or if the config parameter is NULL.

EXAMPLE

       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 = "XXX TODO SAMPLE"

       rc = Tss2_Tcti_Cmd_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_Cmd_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);
       }

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/.