tctildr: Add library to automate TCTI lifecycle.

Instantiating a TCTI context takes a bit of work. The default offered
by ESYS is a good start but this still leaves applications that need to
override the default with a lot of extra work. libtss2-tctildr will do
this work for you.
It provides:
- Tss2_TctiLdr_Initialize - Allocate and initialize a TCTI context for
  the caller. The 'name' parameter is a string that is either passed to
  dlopen, or mapped to an internal table of names to TCTIs linked
  directly into the loader.
- Tss2_TctiLdr_Finalize - The dual of 'Initialize'.

'Initialize' returns a TCTI instance that can be used by the existing
SYS & ESYS APIs. When no longer in use it must be freed using the paired
'Finalize' function.

This implementation reuses the esys_tcti_default module to preserve
existing behavior / default TCTI selection logic as much as possible.
The interface however is very different as callers may now search for
TCTIs using the 'name' parameter of Tss2_TctiLdr_Initialize. When this
parameter is NULL the old default selection logic is used to select a
default TCTI. When it is populated the library will attempt to load it.

On a system with 'dlopen' we simply pass the provided name through which
requires the caller provide the full name of the TCTI library (i.e.
libtss2-tcti-device.so.0). For the NO_DL case this commit introduces a
lookup mechanism for common TCTI names that we compare to the provided
'name'.

The ESYS unit tests have been updated and new unit tests added to cover
the dl & nodl, and tctildr modules. The build (both autotools and visual
studio) has been updated to include rules to build this new library and
to update dependencies:
- tss2-esys no longer depnds on the TCTIs directly
- tss2-esys now depends on tss2-tctildr

This includes a page in section 7 for the library itself as well as
individual pages in section 3 for the initialize and finalize functions.

Signed-off-by: Philip Tricca <philip.b.tricca@intel.com>

2 files changed, 23 insertions, 0 deletions

diff --git a/include/tss2/tss2_common.h b/include/tss2/tss2_common.h
index 6cb5d553..587866d1 100644
--- a/include/tss2/tss2_common.h
+++ b/include/tss2/tss2_common.h
@@ -134,6 +134,8 @@ typedef uint32_t TSS2_RC;
                                                      TSS2_BASE_RC_MALFORMED_RESPONSE))
 #define TSS2_TCTI_RC_NOT_SUPPORTED              ((TSS2_RC)(TSS2_TCTI_RC_LAYER | \
                                                      TSS2_BASE_RC_NOT_SUPPORTED))
+#define TSS2_TCTI_RC_MEMORY                     ((TSS2_RC)(TSS2_TCTI_RC_LAYER | \
+                                                     TSS2_BASE_RC_MEMORY))
 /* SAPI error codes */
 #define TSS2_SYS_RC_GENERAL_FAILURE            ((TSS2_RC)(TSS2_SYS_RC_LAYER | \
                                                     TSS2_BASE_RC_GENERAL_FAILURE))
diff --git a/include/tss2/tss2_tctildr.h b/include/tss2/tss2_tctildr.h
new file mode 100644
index 00000000..32492db8
--- /dev/null
+++ b/include/tss2/tss2_tctildr.h
@@ -0,0 +1,21 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ * Copyright 2018-2019 Intel Corporation
+ */
+#ifndef TSS2_TCTILDR_H
+#define TSS2_TCTILDR_H
+
+#include <inttypes.h>
+#include <stdlib.h>
+
+#include "tss2_tpm2_types.h"
+#include "tss2_tcti.h"
+
+void
+Tss2_TctiLdr_Finalize (TSS2_TCTI_CONTEXT **context);
+TSS2_RC
+Tss2_TctiLdr_Initialize (const char *name,
+                         const char *conf,
+                         TSS2_TCTI_CONTEXT **context);
+
+#endif /* TSS2_TCTILDR_H */