Adds a TBS TctiNameConf.

When parallaxsecond#477 got merged it became possible to build
using a path to the ```tpm2-tss``` installation
instead of depending on ```pkg-config```.

This made it possible to build under Windows. To
further increase the support for the windows
platform this commit moves the option for TBS
TCTI that is being introduced in parallaxsecond#523 into a
separate commit.

This commit also updates the documentation
regarding building using an installation
folder.

Co-authored-by: Thomas Epperson <thomas.epperson@gmail.com>
Signed-off-by: Jesper Brynolf <jesper.brynolf@gmail.com>

tss-esapi-sys/README.md

@@ -62,4 +62,26 @@ wrapper script around `pkg-config` can be seen
 Be advised that in some cases the linker used might need to be set manually in
 `.cargo/config`.
 
+## Locally built tpm2-tss
+It is now possible to specify an installation path when building the crate. This will
+make the build process trying to find all the libraries and header files it needs from
+installation path instead of using `pkg-config`.
+
+The `TPM2_TSS_PATH` environment variable name is used to specify the path to the installation.
+The installation is required to have a specific layout.
+
+```md
+Installation folder
+├── bin (Optional)
+│   ├── tss2-*.dll (Windows)
+├── include (Required)
+│   ├── tss2
+│   │   ├── tss2_*.h
+├── lib (Required)
+│   ├── tss2-*.lib (Windows)
+│   ├── tss2-*.so  (Nix)
+│   ├── tss2-*.pdb (Windows)
+└── VERSION (Required)
+```
+
 *Copyright 2021 Contributors to the Parsec project.*

tss-esapi/src/tcti_ldr.rs

@@ -21,6 +21,7 @@ const DEVICE: &str = "device";
 const MSSIM: &str = "mssim";
 const SWTPM: &str = "swtpm";
 const TABRMD: &str = "tabrmd";
+const TBS: &str = "tbs";
 
 /// TCTI Context created via a TCTI Loader Library.
 /// Wrapper around the TSS2_TCTI_CONTEXT structure.
@@ -143,6 +144,10 @@ pub enum TctiNameConf {
     ///
     /// For more information about configuration, see [this page](https://www.mankier.com/3/Tss2_Tcti_Tabrmd_Init)
     Tabrmd(TabrmdConfig),
+    /// Connect to the tpm using the Trusted Platform Module (TPM) Base Services (TBS) on Windows.
+    ///
+    /// For more information about TBS, see [this page](https://learn.microsoft.com/en-us/windows/win32/tbs/about-tbs)
+    Tbs,
 }
 
 impl TctiNameConf {
@@ -174,6 +179,7 @@ impl TryFrom<TctiNameConf> for CString {
             TctiNameConf::Mssim(..) => MSSIM,
             TctiNameConf::Swtpm(..) => SWTPM,
             TctiNameConf::Tabrmd(..) => TABRMD,
+            TctiNameConf::Tbs => TBS,
         };
 
         let tcti_conf = match tcti {
@@ -204,6 +210,7 @@ impl TryFrom<TctiNameConf> for CString {
             TctiNameConf::Tabrmd(config) => {
                 format!("bus_name={},bus_type={}", config.bus_name, config.bus_type)
             }
+            TctiNameConf::Tbs => String::new(),
         };
 
         if tcti_conf.is_empty() {
@@ -247,6 +254,10 @@ impl FromStr for TctiNameConf {
             )?));
         }
 
+        if config_str.trim() == TBS {
+            return Ok(TctiNameConf::Tbs);
+        }
+
         Err(Error::WrapperError(WrapperErrorKind::InvalidParam))
     }
 }
@@ -327,6 +338,10 @@ fn validate_from_str_tcti() {
 
     let tcti = TctiNameConf::from_str("tabrmd").unwrap();
     assert_eq!(tcti, TctiNameConf::Tabrmd(Default::default()));
+
+    let tcti_tbs = TctiNameConf::from_str("tbs")
+        .expect("It should be possible to convert the string 'tbs' into a TctiNameConf object.");
+    assert_eq!(tcti_tbs, TctiNameConf::Tbs);
 }
 
 /// Configuration for a Device TCTI context