Add runtime property HOSTFXR_PATH (#55369)

* Add property HOSTFXR_PATH

* Comment

* PR feedback

* Use get_own_module_path since we are on hostfxr

* Dispose FileStream

4 files changed, 32 insertions, 4 deletions

diff --git a/src/native/corehost/fxr/corehost_init.cpp b/src/native/corehost/fxr/corehost_init.cpp
index eea9b768f5f..2d169348fa6 100644
--- a/src/native/corehost/fxr/corehost_init.cpp
+++ b/src/native/corehost/fxr/corehost_init.cpp
@@ -20,7 +20,8 @@ corehost_init_t::corehost_init_t(
     const pal::string_t& additional_deps_serialized,
     const std::vector<pal::string_t>& probe_paths,
     const host_mode_t mode,
-    const fx_definition_vector_t& fx_definitions)
+    const fx_definition_vector_t& fx_definitions,
+    const std::vector<std::pair<pal::string_t, pal::string_t>>& additional_properties)
     : m_tfm(get_app(fx_definitions).get_runtime_config().get_tfm())
     , m_deps_file(deps_file)
     , m_additional_deps_serialized(additional_deps_serialized)
@@ -35,6 +36,12 @@ corehost_init_t::corehost_init_t(
 {
     make_cstr_arr(m_probe_paths, &m_probe_paths_cstr);
 
+    for (const auto& additional_property : additional_properties)
+    {
+        m_clr_keys.push_back(additional_property.first);
+        m_clr_values.push_back(additional_property.second);
+    }
+
     size_t fx_count = fx_definitions.size();
     m_fx_names.reserve(fx_count);
     m_fx_dirs.reserve(fx_count);
diff --git a/src/native/corehost/fxr/corehost_init.h b/src/native/corehost/fxr/corehost_init.h
index 70ea7be46fb..6c3148b6274 100644
--- a/src/native/corehost/fxr/corehost_init.h
+++ b/src/native/corehost/fxr/corehost_init.h
@@ -45,7 +45,8 @@ public:
         const pal::string_t& additional_deps_serialized,
         const std::vector<pal::string_t>& probe_paths,
         const host_mode_t mode,
-        const fx_definition_vector_t& fx_definitions);
+        const fx_definition_vector_t& fx_definitions,
+        const std::vector<std::pair<pal::string_t, pal::string_t>>& additional_properties);
 
     const host_interface_t& get_host_init_data();
 
diff --git a/src/native/corehost/fxr/fx_muxer.cpp b/src/native/corehost/fxr/fx_muxer.cpp
index 6a20206e2ca..8647130c18d 100644
--- a/src/native/corehost/fxr/fx_muxer.cpp
+++ b/src/native/corehost/fxr/fx_muxer.cpp
@@ -370,6 +370,7 @@ namespace
         const pal::string_t &app_candidate,
         const opt_map_t &opts,
         host_mode_t mode,
+        const bool is_sdk_command,
         /*out*/ pal::string_t &hostpolicy_dir,
         /*out*/ std::unique_ptr<corehost_init_t> &init)
     {
@@ -473,6 +474,16 @@ namespace
             }
         }
 
+        std::vector<std::pair<pal::string_t, pal::string_t>> additional_properties;
+        if (is_sdk_command)
+        {
+            pal::string_t fxr_path;
+            pal::get_own_module_path(&fxr_path);
+
+            // We pass the loaded hostfxr path to the SDK can load it without relying on dlopen/LoadLibrary to find it.
+            additional_properties.push_back(std::make_pair(_X("HOSTFXR_PATH"), fxr_path));
+        }
+
         const known_options opts_probe_path = known_options::additional_probing_path;
         std::vector<pal::string_t> spec_probe_paths = opts.count(opts_probe_path) ? opts.find(opts_probe_path)->second : std::vector<pal::string_t>();
         std::vector<pal::string_t> probe_realpaths = get_probe_realpaths(fx_definitions, spec_probe_paths);
@@ -485,7 +496,7 @@ namespace
             return StatusCode::CoreHostLibMissingFailure;
         }
 
-        init.reset(new corehost_init_t(host_command, host_info, deps_file, additional_deps_serialized, probe_realpaths, mode, fx_definitions));
+        init.reset(new corehost_init_t(host_command, host_info, deps_file, additional_deps_serialized, probe_realpaths, mode, fx_definitions, additional_properties));
 
         return StatusCode::Success;
     }
@@ -498,6 +509,7 @@ namespace
         int new_argc,
         const pal::char_t** new_argv,
         host_mode_t mode,
+        const bool is_sdk_command,
         pal::char_t out_buffer[],
         int32_t buffer_size,
         int32_t* required_buffer_size)
@@ -510,6 +522,7 @@ namespace
             app_candidate,
             opts,
             mode,
+            is_sdk_command,
             hostpolicy_dir,
             init);
         if (rc != StatusCode::Success)
@@ -572,6 +585,7 @@ int fx_muxer_t::execute(
             argv,
             new_argoff,
             mode,
+            false /*is_sdk_command*/,
             result_buffer,
             buffer_size,
             required_buffer_size);
@@ -621,7 +635,8 @@ namespace
         }
 
         const pal::string_t additional_deps_serialized;
-        init.reset(new corehost_init_t(pal::string_t{}, host_info, deps_file, additional_deps_serialized, probe_realpaths, mode, fx_definitions));
+        const std::vector<std::pair<pal::string_t, pal::string_t>> additional_properties;
+        init.reset(new corehost_init_t(pal::string_t{}, host_info, deps_file, additional_deps_serialized, probe_realpaths, mode, fx_definitions, additional_properties));
 
         return StatusCode::Success;
     }
@@ -725,6 +740,7 @@ int fx_muxer_t::initialize_for_app(
         host_info.app_path,
         opts,
         mode,
+        false /*is_sdk_command*/,
         hostpolicy_dir,
         init);
     if (rc != StatusCode::Success)
@@ -978,6 +994,7 @@ int fx_muxer_t::handle_exec_host_command(
     const pal::char_t* argv[],
     int argoff,
     host_mode_t mode,
+    const bool is_sdk_command,
     pal::char_t result_buffer[],
     int32_t buffer_size,
     int32_t* required_buffer_size)
@@ -1006,6 +1023,7 @@ int fx_muxer_t::handle_exec_host_command(
         new_argc,
         new_argv,
         mode,
+        is_sdk_command,
         result_buffer,
         buffer_size,
         required_buffer_size);
@@ -1096,6 +1114,7 @@ int fx_muxer_t::handle_cli(
             new_argv.data(),
             new_argoff,
             host_mode_t::muxer,
+            true /*is_sdk_command*/,
             nullptr /*result_buffer*/,
             0 /*buffer_size*/,
             nullptr/*required_buffer_size*/);
diff --git a/src/native/corehost/fxr/fx_muxer.h b/src/native/corehost/fxr/fx_muxer.h
index 6794e2a1c82..b3a0e000470 100644
--- a/src/native/corehost/fxr/fx_muxer.h
+++ b/src/native/corehost/fxr/fx_muxer.h
@@ -47,6 +47,7 @@ private:
         const pal::char_t* argv[],
         int argoff,
         host_mode_t mode,
+        const bool is_sdk_command,
         pal::char_t result_buffer[],
         int32_t buffer_size,
         int32_t* required_buffer_size);