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

7 files changed, 102 insertions, 17 deletions

diff --git a/src/installer/tests/Assets/TestProjects/RuntimeProperties/Program.cs b/src/installer/tests/Assets/TestProjects/RuntimeProperties/Program.cs
index d22677aa617..96fa3b2adba 100644
--- a/src/installer/tests/Assets/TestProjects/RuntimeProperties/Program.cs
+++ b/src/installer/tests/Assets/TestProjects/RuntimeProperties/Program.cs
@@ -14,7 +14,14 @@ namespace RuntimeProperties
 
             foreach (string propertyName in args)
             {
-                Console.WriteLine($"AppContext.GetData({propertyName}) = {System.AppContext.GetData(propertyName)}");
+                var propertyValue = (string)System.AppContext.GetData(propertyName);
+                if (string.IsNullOrEmpty(propertyValue))
+                {
+                    Console.WriteLine($"Property '{propertyName}' was not found.");
+                    continue;
+                }
+
+                Console.WriteLine($"AppContext.GetData({propertyName}) = {propertyValue}");
             }
         }
     }
diff --git a/src/installer/tests/HostActivation.Tests/DotNetBuilder.cs b/src/installer/tests/HostActivation.Tests/DotNetBuilder.cs
index 2a99ab5681f..0a8d54559e2 100644
--- a/src/installer/tests/HostActivation.Tests/DotNetBuilder.cs
+++ b/src/installer/tests/HostActivation.Tests/DotNetBuilder.cs
@@ -174,6 +174,22 @@ namespace Microsoft.DotNet.CoreSetup.Test.HostActivation
             return this;
         }
 
+        public DotNetBuilder AddMockSDK(
+            string version,
+            string MNAVersion)
+        {
+            string path = Path.Combine(_path, "sdk", version);
+            Directory.CreateDirectory(path);
+
+            using var _ = File.Create(Path.Combine(path, "dotnet.dll"));
+
+            RuntimeConfig dotnetRuntimeConfig = new RuntimeConfig(Path.Combine(path, "dotnet.runtimeconfig.json"));
+            dotnetRuntimeConfig.WithFramework(new RuntimeConfig.Framework("Microsoft.NETCore.App", MNAVersion));
+            dotnetRuntimeConfig.Save();
+
+            return this;
+        }
+
         public DotNetCli Build()
         {
             return new DotNetCli(_path);
diff --git a/src/installer/tests/HostActivation.Tests/RuntimeProperties.cs b/src/installer/tests/HostActivation.Tests/RuntimeProperties.cs
index 6d8949c4132..01b5b415ecd 100644
--- a/src/installer/tests/HostActivation.Tests/RuntimeProperties.cs
+++ b/src/installer/tests/HostActivation.Tests/RuntimeProperties.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.IO;
+using Microsoft.DotNet.Cli.Build;
 using Xunit;
 
 namespace Microsoft.DotNet.CoreSetup.Test.HostActivation
@@ -25,9 +26,7 @@ namespace Microsoft.DotNet.CoreSetup.Test.HostActivation
             var dotnet = fixture.BuiltDotnet;
             var appDll = fixture.TestProject.AppDll;
             dotnet.Exec(appDll, sharedState.AppTestPropertyName)
-                .EnvironmentVariable("COREHOST_TRACE", "1")
-                .CaptureStdErr()
-                .CaptureStdOut()
+                .EnableTracingAndCaptureOutputs()
                 .Execute()
                 .Should().Pass()
                 .And.HaveStdErrContaining($"Property {sharedState.AppTestPropertyName} = {sharedState.AppTestPropertyValue}")
@@ -43,9 +42,7 @@ namespace Microsoft.DotNet.CoreSetup.Test.HostActivation
             var dotnet = fixture.BuiltDotnet;
             var appDll = fixture.TestProject.AppDll;
             dotnet.Exec(appDll, sharedState.FrameworkTestPropertyName)
-                .EnvironmentVariable("COREHOST_TRACE", "1")
-                .CaptureStdErr()
-                .CaptureStdOut()
+                .EnableTracingAndCaptureOutputs()
                 .Execute()
                 .Should().Pass()
                 .And.HaveStdErrContaining($"Property {sharedState.FrameworkTestPropertyName} = {sharedState.FrameworkTestPropertyValue}")
@@ -65,9 +62,7 @@ namespace Microsoft.DotNet.CoreSetup.Test.HostActivation
             var dotnet = fixture.BuiltDotnet;
             var appDll = fixture.TestProject.AppDll;
             dotnet.Exec(appDll, sharedState.FrameworkTestPropertyName)
-                .EnvironmentVariable("COREHOST_TRACE", "1")
-                .CaptureStdErr()
-                .CaptureStdOut()
+                .EnableTracingAndCaptureOutputs()
                 .Execute()
                 .Should().Pass()
                 .And.HaveStdErrContaining($"Property {sharedState.FrameworkTestPropertyName} = {sharedState.AppTestPropertyValue}")
@@ -75,6 +70,32 @@ namespace Microsoft.DotNet.CoreSetup.Test.HostActivation
         }
 
         [Fact]
+        public void HostFxrPathProperty_SetWhenRunningSDKCommand()
+        {
+            var dotnet = sharedState.MockSDK;
+            dotnet.Exec("--info")
+                .EnableTracingAndCaptureOutputs()
+                .Execute()
+                .Should().Pass()
+                .And.HaveStdErrContaining($"Property {sharedState.HostFxrPathPropertyName} = {dotnet.GreatestVersionHostFxrFilePath}");
+        }
+
+        [Fact]
+        public void HostFxrPathProperty_NotVisibleFromApp()
+        {
+            var fixture = sharedState.RuntimePropertiesFixture
+                .Copy();
+
+            var dotnet = fixture.BuiltDotnet;
+            var appDll = fixture.TestProject.AppDll;
+            dotnet.Exec(appDll, sharedState.HostFxrPathPropertyName)
+                .EnableTracingAndCaptureOutputs()
+                .Execute()
+                .Should().Pass()
+                .And.HaveStdOutContaining($"Property '{sharedState.HostFxrPathPropertyName}' was not found.");
+        }
+
+        [Fact]
         public void DuplicateCommonProperty_Fails()
         {
             var fixture = sharedState.RuntimePropertiesFixture
@@ -88,9 +109,7 @@ namespace Microsoft.DotNet.CoreSetup.Test.HostActivation
             var dotnet = fixture.BuiltDotnet;
             var appDll = fixture.TestProject.AppDll;
             dotnet.Exec(appDll)
-                .EnvironmentVariable("COREHOST_TRACE", "1")
-                .CaptureStdErr()
-                .CaptureStdOut()
+                .EnableTracingAndCaptureOutputs()
                 .Execute()
                 .Should().Fail()
                 .And.HaveStdErrContaining($"Duplicate runtime property found: {name}");
@@ -100,11 +119,13 @@ namespace Microsoft.DotNet.CoreSetup.Test.HostActivation
         {
             public TestProjectFixture RuntimePropertiesFixture { get; }
             public RepoDirectoriesProvider RepoDirectories { get; }
+            public DotNetCli MockSDK { get; }
 
             public string AppTestPropertyName => "APP_TEST_PROPERTY";
             public string AppTestPropertyValue => "VALUE_FROM_APP";
             public string FrameworkTestPropertyName => "FRAMEWORK_TEST_PROPERTY";
             public string FrameworkTestPropertyValue => "VALUE_FROM_FRAMEWORK";
+            public string HostFxrPathPropertyName => "HOSTFXR_PATH";
 
             private readonly string copiedDotnet;
 
@@ -113,6 +134,19 @@ namespace Microsoft.DotNet.CoreSetup.Test.HostActivation
                 copiedDotnet = Path.Combine(TestArtifact.TestArtifactsPath, "runtimeProperties");
                 SharedFramework.CopyDirectory(Path.Combine(TestArtifact.TestArtifactsPath, "sharedFrameworkPublish"), copiedDotnet);
 
+                MockSDK = new DotNetBuilder(copiedDotnet, Path.Combine(TestArtifact.TestArtifactsPath, "sharedFrameworkPublish"), "exe")
+                    .AddMicrosoftNETCoreAppFrameworkMockCoreClr("9999.0.0")
+                    .AddMockSDK("9999.0.0-dev", "9999.0.0")
+                    .Build();
+
+                File.WriteAllText(Path.Combine(MockSDK.BinPath, "global.json"),
+                    @"
+{
+    ""sdk"": {
+      ""version"": ""9999.0.0-dev""
+    }
+}");
+
                 RepoDirectories = new RepoDirectoriesProvider(builtDotnet: copiedDotnet);
 
                 RuntimePropertiesFixture = new TestProjectFixture("RuntimeProperties", RepoDirectories)
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);