TPMLIB_GetTPMProperty(3)                              TPMLIB_GetTPMProperty(3)


NAME
       TPMLIB_GetTPMProperty    - Get a runtime property of the TPM

LIBRARY
       TPM library (libtpms, -ltpms)

SYNOPSIS
       #include <libtpms/tpm_library.h>

       TPM_RESULT TPMLIB_GetTPMProperty(enum TPMLIB_TPMProperty, int *result);

DESCRIPTION
       The TPMLIB_GetTPMProperty() call is used to retrieve run-time
       parameters of the TPM such as the number of authorization sessions it
       can hold or the maximum sizes of the permanent state, savestate or
       volatile state blobs.

       This function can be called before or after the TPM has been created.
       The current implementation of libtpms will return the same value before
       and after the TPM was started.

       With the introduction of the function TPMLIB_ChooseTPMVersion(), the
       call to this function should be executed after the TPM version has been
       chosen. The reason is that different TPM versions may return different
       values.

       The following properties have been defined:

       TPMPROP_TPM_RSA_KEY_LENGTH_MAX
           The maximum size of an RSA key.

       TPMPROP_TPM_BUFFER_MAX
           The maximum sizes of the TPM command and result buffers.

       TPMPROP_TPM_KEY_HANDLES
           The number of key slots.

       TPMPROP_TPM_OWNER_EVICT_KEY_HANDLES
           The number of owner-evict keys.

       TPMPROP_TPM_MIN_AUTH_SESSIONS
           The number of authorization sessions.

       TPMPROP_TPM_MIN_TRANS_SESSIONS
           The number of transport sessions.

       TPMPROP_TPM_MIN_DAA_SESSIONS
           The number of DAA sessions.

       TPMPROP_TPM_MIN_SESSION_LIST
           The size of the session list.

       TPMPROP_TPM_MIN_COUNTERS
           The number of monotonic counters.

       TPMPROP_TPM_NUM_FAMILY_TABLE_ENTRY_MIN
           The number of family entries.

       TPMPROP_TPM_NUM_DELEGATE_TABLE_ENTRY_MIN
           The number of delegate entries.

       TPMPROP_TPM_SPACE_SAFETY_MARGIN
           The space safety margin used for the worst-case sizes of the
           savestate and volatile state blobs. This safety margin is not used
           for the size of the permanent data blob.

       TPMPROP_TPM_MAX_NV_SPACE
           The maximum size of the permanent data blob.

       TPMPROP_TPM_MAX_SAVESTATE_SPACE
           The maximum size of the savestate blob (includes the space safety
           margin).

       TPMPROP_TPM_MAX_VOLATILESTATE_SPACE
           The maximum size of the volatile state blob (includes the space
           saferty margin).

ERRORS
       TPM_SUCCESS
           The function completed successfully.

       TPM_FAIL
           An undefined property was queried.

       For a complete list of TPM error codes please consult the include file
       libtpms/tpm_error.h

EXAMPLE
        #include <stdio.h>

        #include <libtpms/tpm_library.h>
        #include <libtpms/tpm_error.h>

        int main(void) {
            TPM_RESULT res;
            int result;
            int rc = 0;

            if (TPMLIB_MainInit() != TPM_SUCCESS) {
                fprintf(stderr, "Could not start the TPM.\n");
                return 1;
            }

            if (TPMLIB_GetTPMProperty(TPMPROP_TPM_RSA_KEY_LENGTH_MAX, &result)
                != TPM_SUCCESS) {
                fprintf(stderr, "Could not read the max. size of RSA keys.\n");
                goto err_exit;
            }

            fprintf(stdout, "Max. size of RSA keys: %d\n", result);

        err_exit:
            TPMLIB_Terminate();

            return 0;
        }

SEE ALSO
       TPMLIB_MainInit(3), TPMLIB_Terminate(3), TPMLIB_Process(3),
       TPMLIB_RegisterCallbacks(3), TPMLIB_GetVersion(3),
       TPMLIB_ChooseTPMVersion(3)

libtpms                           2023-05-07          TPMLIB_GetTPMProperty(3)