Enable full static linking of libtss2 when using "bundled" feature

tss-esapi-sys/Cargo.toml

@@ -15,15 +15,17 @@ rust-version = "1.85.0"
 
 [build-dependencies]
 bindgen = { version = "0.72.1", optional = true }
-pkg-config = "0.3.33"
-target-lexicon = "0.13.5"
 cfg-if = "1.0.4"
+pkg-config = "0.3.33"
 semver = "1.0.27"
-autotools = { version = "0.2.7", optional = true }
+target-lexicon = "0.13.5"
 
 [target.'cfg(windows)'.build-dependencies]
 msbuild = { version = "0.2.1", optional = true }
 
+[target.'cfg(not(windows))'.build-dependencies]
+autotools = { version = "0.2.7", optional = true }
+
 [features]
-generate-bindings = ["bindgen", "dep:msbuild"]
+generate-bindings = ["dep:bindgen", "dep:autotools", "dep:msbuild"]
 bundled = ["dep:autotools", "dep:msbuild"]

tss-esapi-sys/README.md

@@ -53,9 +53,7 @@ Github during the build. The version to retrieve can be controlled by setting
 the `TPM2_TSS_SOURCE_VERSION` environment variable.
 [!IMPORTANT]
 * The `bundled` feature will make it possible to build the crate without
-   having to worry about the `tpm2-tss` library dependencies. But it is still
-   necessary to make the shared libraries available to the executable that uses
-   the library.
+   having to worry about the `tpm2-tss` library dependencies. 
 * The dependencies of `tpm2-tss` need to be installed and discoverable via
   `pkg-config` on all platforms except Windows, on Windows this is handled
   differently. See the [Windows section](#windows).
@@ -128,6 +126,25 @@ sudo zypper in \
    make
 ```
 
+## Bundling and Static Linking
+
+When building with the `bundled` feature, the tss-esapi-sys crate makes use of the
+[`--enable-nodl`](https://github.com/tpm2-software/tpm2-tss/blob/be602a5/configure.ac#L396) option
+in `autoconf`. This configures the library such that TCTIs are directly linked via the bundled
+library statically, without any use of `dlopen` to call into these libraries at runtime. As such,
+all TCTIs (swtpm, device, mssim) will be linked statically to the resulting tss-esapi-sys crate, as
+the symbols will be present in the compiled artefacts and `cargo` will need to see them to
+successfully link any TCTI libraries.
+
+This is likely what you want if you want a fully-static bundled installation of the libtss2 library.
+If you want to link to TCTIs dynamically, you should first install a compatible version of libtss2
+and either set up pkg-config to find it, or configure your `TPM2_TSS_PATH` manually.
+
+**NOTE**: On Windows builds, `msbuild` is used instead of `autotools`, and so these assumptions
+should be checked and verified. The `nodl` configuration option should be set to ensure your bundled
+library links fully statically, or you should expect that you will need to have the dynamic TCTI
+libraries present at runtime as they may be called via `dlopen`.
+
 ## Cross compiling
 
 Cross-compilation can be done as long as you have on your build system the TSS

tss-esapi-sys/build.rs

@@ -150,6 +150,12 @@ pub mod tpm2_tss {
         tss2_mu: Library,
         #[allow(unused)]
         tss2_tcti_tbs: Option<Library>,
+        #[allow(unused)]
+        tss2_tcti_device: Option<Library>,
+        #[allow(unused)]
+        tss2_tcti_swtpm: Option<Library>,
+        #[allow(unused)]
+        tss2_tcti_mssim: Option<Library>,
     }
 
     impl Installation {
@@ -173,6 +179,21 @@ pub mod tpm2_tss {
                 ),
                 tss2_mu: Library::bundled_required("tss2-mu", &source_path, &version, false),
                 tss2_tcti_tbs: Library::bundled_optional("tss2-tcti-tbs", &source_path, &version),
+                tss2_tcti_device: Library::bundled_optional(
+                    "tss2-tcti-device",
+                    &source_path,
+                    &version,
+                ),
+                tss2_tcti_swtpm: Library::bundled_optional(
+                    "tss2-tcti-swtpm",
+                    &source_path,
+                    &version,
+                ),
+                tss2_tcti_mssim: Library::bundled_optional(
+                    "tss2-tcti-mssim",
+                    &source_path,
+                    &version,
+                ),
             }
         }
 
@@ -209,6 +230,14 @@ pub mod tpm2_tss {
                     install_path.as_ref(),
                     with_header_files,
                 ),
+                // When dynamically linked, the TCTI library will dlopen these itself.
+                //
+                // See: the `--enable-nodl` configuration at
+                //
+                // <https://github.com/tpm2-software/tpm2-tss/blob/master/configure.ac#L396>
+                tss2_tcti_device: None,
+                tss2_tcti_swtpm: None,
+                tss2_tcti_mssim: None,
             }
         }
 
@@ -426,9 +455,8 @@ pub mod tpm2_tss {
                             .expect("Unable to create version file for tpm2-tss");
                         write!(version_file, "{}", Self::version())
                             .unwrap_or_else(|e| panic!("Failed to write version file: {e}"));
-            }
-                }
-                else {
+                    }
+                } else {
                     let install_path = Self::compile_with_autotools(source_path);
 
                     // On some systems the files are installed to the lib64 dir
@@ -477,6 +505,7 @@ pub mod tpm2_tss {
                 .reconf("-fiv")
                 // skip ./configure if no parameter changes are made
                 .fast_build(true)
+                .enable("nodl", Some("yes"))
                 .enable("esys", None)
                 // Disable fapi as we only use esys
                 .disable("fapi", None)