Convert apphost to C

src/native/corehost/apphost/apphost.c

@@ -0,0 +1,389 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#include "pal.h"
+#include "trace.h"
+#include "utils.h"
+#include "bundle_marker.h"
+#include "apphost_hostfxr_resolver.h"
+#include "error_codes.h"
+#include "hostfxr.h"
+
+#if defined(_WIN32)
+#include "apphost.windows.h"
+#include <_version.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+#if defined(FEATURE_STATIC_HOST)
+extern void apphost_static_init(void);
+#endif
+
+/**
+ * Detect if the apphost executable is allowed to load and execute a managed assembly.
+ *
+ * - The exe is built with a known hash string at some offset in the image
+ * - The exe is useless as is with the built-in hash value, and will fail with an error message
+ * - The hash value should be replaced with the managed DLL filename with optional relative path
+ * - The optional path is relative to the location of the apphost executable
+ * - The relative path plus filename are verified to reference a valid file
+ * - The filename should be "NUL terminated UTF-8" by "dotnet build"
+ * - The managed DLL filename does not have to be the same name as the apphost executable name
+ * - The exe may be signed at this point by the app publisher
+ * - Note: the maximum size of the filename and relative path is 1024 bytes in UTF-8 (not including NUL)
+ * o https://en.wikipedia.org/wiki/Comparison_of_file_systems
+ * has more details on maximum file name sizes.
+ */
+#define EMBED_HASH_HI_PART_UTF8 "c3ab8ff13720e8ad9047dd39466b3c89" // SHA-256 of "foobar" in UTF-8
+#define EMBED_HASH_LO_PART_UTF8 "74e592c2fa383d4a3960714caef0c4f2"
+#define EMBED_HASH_FULL_UTF8 (EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8) // NUL terminated
+
+#define EMBED_SZ (int)(sizeof(EMBED_HASH_FULL_UTF8) / sizeof(EMBED_HASH_FULL_UTF8[0]))
+#define EMBED_MAX (EMBED_SZ > 1025 ? EMBED_SZ : 1025) // 1024 DLL name length, 1 NUL
+
+// This avoids compiler optimization which cause EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8
+// to be placed adjacent causing them to match EMBED_HASH_FULL_UTF8 when searched for replacing.
+// See https://github.com/dotnet/runtime/issues/109611 for more details.
+static bool compare_memory_nooptimization(volatile const char* a, volatile const char* b, size_t length)
+{
+ for (size_t i = 0; i < length; i++)
+ {
+ if (*a++ != *b++)
+ return false;
+ }
+ return true;
+}
+
+// app_dll receives the embedded DLL name as a pal_char_t string.
+// app_dll_len is the buffer size in pal_char_t characters.
+static bool is_exe_enabled_for_execution(pal_char_t* app_dll, size_t app_dll_len)
+{
+ // Contains the EMBED_HASH_FULL_UTF8 value at compile time or the managed DLL name replaced by "dotnet build".
+ // Must not be 'const' because strlen below could be determined at compile time (=64) instead of the actual
+ // length of the string at runtime.
+ // Always narrow UTF-8, regardless of platform.
+ static char embed[EMBED_MAX] = EMBED_HASH_FULL_UTF8;
+
+ static const char hi_part[] = EMBED_HASH_HI_PART_UTF8;
+ static const char lo_part[] = EMBED_HASH_LO_PART_UTF8;
+
+ size_t binding_len = strlen(&embed[0]);
+
+ if (binding_len == 0 || binding_len >= app_dll_len)
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ // Check if the path exceeds the max allowed size
+ if (binding_len > EMBED_MAX - 1)
+ {
+ trace_error(_X("The managed DLL bound to this executable is longer than the max allowed length (%d)"), EMBED_MAX - 1);
+ return false;
+ }
+
+ // Check if the value is the same as the placeholder to detect unbound executables
+ size_t hi_len = sizeof(hi_part) - 1;
+ size_t lo_len = sizeof(lo_part) - 1;
+ if (binding_len >= (hi_len + lo_len)
+ && compare_memory_nooptimization(&embed[0], hi_part, hi_len)
+ && compare_memory_nooptimization(&embed[hi_len], lo_part, lo_len))
+ {
+ trace_error(_X("This executable is not bound to a managed DLL to execute."));
+ return false;
+ }
+
+ if (!pal_utf8_to_palstr(&embed[0], app_dll, app_dll_len))
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ trace_info(_X("The managed DLL bound to this executable is: '%s'"), app_dll);
+ return true;
+}
+
+static void report_outdated_framework_error(const pal_char_t* dotnet_root, const pal_char_t* host_path)
+{
+ pal_char_t download_url[MAX_DOWNLOAD_URL_LEN];
+ utils_get_download_url(download_url, ARRAY_SIZE(download_url), NULL, NULL);
+
+ trace_error(
+ MISSING_RUNTIME_ERROR_FORMAT,
+ INSTALL_OR_UPDATE_NET_ERROR_MESSAGE,
+ host_path,
+ _STRINGIFY(CURRENT_ARCH_NAME),
+ _STRINGIFY(HOST_VERSION),
+ dotnet_root,
+ download_url,
+ _STRINGIFY(HOST_VERSION));
+}
+
+// C equivalent of propagate_error_writer_t
+typedef struct {
+ hostfxr_set_error_writer_fn set_error_writer;
+ bool error_writer_set;
+} propagate_error_writer_state_t;
+
+static void propagate_error_writer_init(propagate_error_writer_state_t* state, hostfxr_set_error_writer_fn set_error_writer)
+{
+ trace_flush();
+
+ state->set_error_writer = set_error_writer;
+ state->error_writer_set = false;
+
+ trace_error_writer_fn error_writer = trace_get_error_writer();
+ if (error_writer != NULL && set_error_writer != NULL)
+ {
+ set_error_writer((hostfxr_error_writer_fn)error_writer);
+ state->error_writer_set = true;
+ }
+}
+
+static void propagate_error_writer_cleanup(propagate_error_writer_state_t* state)
+{
+ if (state->error_writer_set && state->set_error_writer != NULL)
+ {
+ state->set_error_writer(NULL);
+ state->error_writer_set = false;
+ }
+}
+
+static int exe_start(const int argc, const pal_char_t* argv[])
+{
+#if defined(FEATURE_STATIC_HOST)
+ apphost_static_init();
+#endif
+
+ // Use realpath/GetModuleFileName to find the path of the host, resolving any symlinks.
+ pal_char_t* host_path = pal_get_own_executable_path();
+ if (host_path == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), _X("<unknown>"));
+ return CurrentHostFindFailure;
+ }
+
+ pal_char_t* host_path_full = pal_fullpath(host_path, false);
+ if (host_path_full == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), host_path);
+ free(host_path);
+ return CurrentHostFindFailure;
+ }
+
+ free(host_path);
+ host_path = host_path_full;
+
+ bool requires_hostfxr_startupinfo_interface = false;
+
+ // FEATURE_APPHOST path: read embedded DLL name
+ pal_char_t embedded_app_name[EMBED_MAX];
+ if (!is_exe_enabled_for_execution(embedded_app_name, ARRAY_SIZE(embedded_app_name)))
+ {
+ free(host_path);
+ return AppHostExeNotBoundFailure;
+ }
+
+#if defined(_WIN32)
+ for (pal_char_t* c = embedded_app_name; *c != _X('\0'); c++)
+ {
+ if (*c == _X('/'))
+ *c = DIR_SEPARATOR;
+ }
+#endif
+
+ if (pal_strchr(embedded_app_name, DIR_SEPARATOR) != NULL)
+ {
+ requires_hostfxr_startupinfo_interface = true;
+ }
+
+ pal_char_t* app_dir = utils_get_directory(host_path);
+ if (app_dir == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ pal_char_t* app_path = utils_append_path_alloc(app_dir, embedded_app_name);
+ free(app_dir);
+ if (app_path == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ const bool is_bundle = bundle_marker_is_bundle();
+ if (is_bundle)
+ {
+ trace_info(_X("Detected Single-File app bundle"));
+ }
+ else
+ {
+ pal_char_t* app_path_full = pal_fullpath(app_path, false);
+ if (app_path_full == NULL)
+ {
+ trace_error(_X("The application to execute does not exist: '%s'."), app_path);
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ free(app_path);
+ app_path = app_path_full;
+ }
+
+ pal_char_t* app_root = utils_get_directory(app_path);
+ if (app_root == NULL)
+ {
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ hostfxr_resolver_t fxr;
+ hostfxr_resolver_init(&fxr, app_root);
+
+ int rc = fxr.status_code;
+ if (rc != Success)
+ {
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+ }
+
+ if (is_bundle)
+ {
+ hostfxr_main_bundle_startupinfo_fn hostfxr_main_bundle_startupinfo = hostfxr_resolver_resolve_main_bundle_startupinfo(&fxr);
+ if (hostfxr_main_bundle_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+ int64_t bundle_header_offset = bundle_marker_header_offset();
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_bundle_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+ trace_info(_X("Bundle Header Offset: [%" PRId64 "]"), bundle_header_offset);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+ rc = hostfxr_main_bundle_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr, bundle_header_offset);
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not support single-file apps."), fxr.fxr_path);
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ rc = FrameworkMissingFailure;
+ }
+ }
+ else
+ {
+ hostfxr_main_startupinfo_fn hostfxr_main_startupinfo = hostfxr_resolver_resolve_main_startupinfo(&fxr);
+ if (hostfxr_main_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+
+ rc = hostfxr_main_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr);
+
+ if (trace_get_error_writer() != NULL && rc == (int)FrameworkMissingFailure && set_error_writer == NULL)
+ {
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ }
+
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+#if !defined(FEATURE_STATIC_HOST)
+ else
+ {
+ if (requires_hostfxr_startupinfo_interface)
+ {
+ trace_error(_X("The required library %s does not support relative app dll paths."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ else
+ {
+ trace_info(_X("Invoking fx resolver [%s] v1"), fxr.fxr_path);
+
+ // Previous corehost trace messages must be printed before calling trace::setup in hostfxr
+ trace_flush();
+
+ hostfxr_main_fn main_fn_v1 = hostfxr_resolver_resolve_main_v1(&fxr);
+ if (main_fn_v1 != NULL)
+ {
+ rc = main_fn_v1(argc, argv);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not contain the expected entry point."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ }
+ }
+#endif // !defined(FEATURE_STATIC_HOST)
+ }
+
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+}
+
+#if defined(_WIN32)
+int __cdecl wmain(int argc, const pal_char_t* argv[])
+#else
+int main(const int argc, const pal_char_t* argv[])
+#endif
+{
+ trace_setup();
+
+ if (trace_is_enabled())
+ {
+ trace_info(_X("--- Invoked apphost [version: ")
+#if defined(_WIN32)
+ _STRINGIFY(VER_PRODUCTVERSION_STR)
+#else
+ _STRINGIFY(HOST_VERSION) _X(" @Commit: ") _STRINGIFY(REPO_COMMIT_HASH)
+#endif
+ _X("] main = {"));
+ for (int i = 0; i < argc; ++i)
+ {
+ trace_info(_X("%s"), argv[i]);
+ }
+ trace_info(_X("}"));
+ }
+
+#if defined(_WIN32)
+ apphost_buffer_errors();
+#endif
+
+ int exit_code = exe_start(argc, argv);
+
+ trace_flush();
+
+#if defined(_WIN32)
+ apphost_write_buffered_errors(exit_code);
+#endif
+
+ return exit_code;
+}

src/native/corehost/apphost/apphost.c

@@ -0,0 +1,389 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#include "pal.h"
+#include "trace.h"
+#include "utils.h"
+#include "bundle_marker.h"
+#include "apphost_hostfxr_resolver.h"
+#include "error_codes.h"
+#include "hostfxr.h"
+
+#if defined(_WIN32)
+#include "apphost.windows.h"
+#include <_version.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+#if defined(FEATURE_STATIC_HOST)
+extern void apphost_static_init(void);
+#endif
+
+/**
+ * Detect if the apphost executable is allowed to load and execute a managed assembly.
+ *
+ * - The exe is built with a known hash string at some offset in the image
+ * - The exe is useless as is with the built-in hash value, and will fail with an error message
+ * - The hash value should be replaced with the managed DLL filename with optional relative path
+ * - The optional path is relative to the location of the apphost executable
+ * - The relative path plus filename are verified to reference a valid file
+ * - The filename should be "NUL terminated UTF-8" by "dotnet build"
+ * - The managed DLL filename does not have to be the same name as the apphost executable name
+ * - The exe may be signed at this point by the app publisher
+ * - Note: the maximum size of the filename and relative path is 1024 bytes in UTF-8 (not including NUL)
+ * o https://en.wikipedia.org/wiki/Comparison_of_file_systems
+ * has more details on maximum file name sizes.
+ */
+#define EMBED_HASH_HI_PART_UTF8 "c3ab8ff13720e8ad9047dd39466b3c89" // SHA-256 of "foobar" in UTF-8
+#define EMBED_HASH_LO_PART_UTF8 "74e592c2fa383d4a3960714caef0c4f2"
+#define EMBED_HASH_FULL_UTF8 (EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8) // NUL terminated
+
+#define EMBED_SZ (int)(sizeof(EMBED_HASH_FULL_UTF8) / sizeof(EMBED_HASH_FULL_UTF8[0]))
+#define EMBED_MAX (EMBED_SZ > 1025 ? EMBED_SZ : 1025) // 1024 DLL name length, 1 NUL
+
+// This avoids compiler optimization which cause EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8
+// to be placed adjacent causing them to match EMBED_HASH_FULL_UTF8 when searched for replacing.
+// See https://github.com/dotnet/runtime/issues/109611 for more details.
+static bool compare_memory_nooptimization(volatile const char* a, volatile const char* b, size_t length)
+{
+ for (size_t i = 0; i < length; i++)
+ {
+ if (*a++ != *b++)
+ return false;
+ }
+ return true;
+}
+
+// app_dll receives the embedded DLL name as a pal_char_t string.
+// app_dll_len is the buffer size in pal_char_t characters.
+static bool is_exe_enabled_for_execution(pal_char_t* app_dll, size_t app_dll_len)
+{
+ // Contains the EMBED_HASH_FULL_UTF8 value at compile time or the managed DLL name replaced by "dotnet build".
+ // Must not be 'const' because strlen below could be determined at compile time (=64) instead of the actual
+ // length of the string at runtime.
+ // Always narrow UTF-8, regardless of platform.
+ static char embed[EMBED_MAX] = EMBED_HASH_FULL_UTF8;
+
+ static const char hi_part[] = EMBED_HASH_HI_PART_UTF8;
+ static const char lo_part[] = EMBED_HASH_LO_PART_UTF8;
+
+ size_t binding_len = strlen(&embed[0]);
+
+ if (binding_len == 0 || binding_len >= app_dll_len)
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ // Check if the path exceeds the max allowed size
+ if (binding_len > EMBED_MAX - 1)
+ {
+ trace_error(_X("The managed DLL bound to this executable is longer than the max allowed length (%d)"), EMBED_MAX - 1);
+ return false;
+ }
+
+ // Check if the value is the same as the placeholder to detect unbound executables
+ size_t hi_len = sizeof(hi_part) - 1;
+ size_t lo_len = sizeof(lo_part) - 1;
+ if (binding_len >= (hi_len + lo_len)
+ && compare_memory_nooptimization(&embed[0], hi_part, hi_len)
+ && compare_memory_nooptimization(&embed[hi_len], lo_part, lo_len))
+ {
+ trace_error(_X("This executable is not bound to a managed DLL to execute."));
+ return false;
+ }
+
+ if (!pal_utf8_to_palstr(&embed[0], app_dll, app_dll_len))
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ trace_info(_X("The managed DLL bound to this executable is: '%s'"), app_dll);
+ return true;
+}
+
+static void report_outdated_framework_error(const pal_char_t* dotnet_root, const pal_char_t* host_path)
+{
+ pal_char_t download_url[MAX_DOWNLOAD_URL_LEN];
+ utils_get_download_url(download_url, ARRAY_SIZE(download_url), NULL, NULL);
+
+ trace_error(
+ MISSING_RUNTIME_ERROR_FORMAT,
+ INSTALL_OR_UPDATE_NET_ERROR_MESSAGE,
+ host_path,
+ _STRINGIFY(CURRENT_ARCH_NAME),
+ _STRINGIFY(HOST_VERSION),
+ dotnet_root,
+ download_url,
+ _STRINGIFY(HOST_VERSION));
+}
+
+// C equivalent of propagate_error_writer_t
+typedef struct {
+ hostfxr_set_error_writer_fn set_error_writer;
+ bool error_writer_set;
+} propagate_error_writer_state_t;
+
+static void propagate_error_writer_init(propagate_error_writer_state_t* state, hostfxr_set_error_writer_fn set_error_writer)
+{
+ trace_flush();
+
+ state->set_error_writer = set_error_writer;
+ state->error_writer_set = false;
+
+ trace_error_writer_fn error_writer = trace_get_error_writer();
+ if (error_writer != NULL && set_error_writer != NULL)
+ {
+ set_error_writer((hostfxr_error_writer_fn)error_writer);
+ state->error_writer_set = true;
+ }
+}
+
+static void propagate_error_writer_cleanup(propagate_error_writer_state_t* state)
+{
+ if (state->error_writer_set && state->set_error_writer != NULL)
+ {
+ state->set_error_writer(NULL);
+ state->error_writer_set = false;
+ }
+}
+
+static int exe_start(const int argc, const pal_char_t* argv[])
+{
+#if defined(FEATURE_STATIC_HOST)
+ apphost_static_init();
+#endif
+
+ // Use realpath/GetModuleFileName to find the path of the host, resolving any symlinks.
+ pal_char_t* host_path = pal_get_own_executable_path();
+ if (host_path == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), _X("<unknown>"));
+ return CurrentHostFindFailure;
+ }
+
+ pal_char_t* host_path_full = pal_fullpath(host_path, false);
+ if (host_path_full == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), host_path);
+ free(host_path);
+ return CurrentHostFindFailure;
+ }
+
+ free(host_path);
+ host_path = host_path_full;
+
+ bool requires_hostfxr_startupinfo_interface = false;
+
+ // FEATURE_APPHOST path: read embedded DLL name
+ pal_char_t embedded_app_name[EMBED_MAX];
+ if (!is_exe_enabled_for_execution(embedded_app_name, ARRAY_SIZE(embedded_app_name)))
+ {
+ free(host_path);
+ return AppHostExeNotBoundFailure;
+ }
+
+#if defined(_WIN32)
+ for (pal_char_t* c = embedded_app_name; *c != _X('\0'); c++)
+ {
+ if (*c == _X('/'))
+ *c = DIR_SEPARATOR;
+ }
+#endif
+
+ if (pal_strchr(embedded_app_name, DIR_SEPARATOR) != NULL)
+ {
+ requires_hostfxr_startupinfo_interface = true;
+ }
+
+ pal_char_t* app_dir = utils_get_directory(host_path);
+ if (app_dir == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ pal_char_t* app_path = utils_append_path_alloc(app_dir, embedded_app_name);
+ free(app_dir);
+ if (app_path == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ const bool is_bundle = bundle_marker_is_bundle();
+ if (is_bundle)
+ {
+ trace_info(_X("Detected Single-File app bundle"));
+ }
+ else
+ {
+ pal_char_t* app_path_full = pal_fullpath(app_path, false);
+ if (app_path_full == NULL)
+ {
+ trace_error(_X("The application to execute does not exist: '%s'."), app_path);
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ free(app_path);
+ app_path = app_path_full;
+ }
+
+ pal_char_t* app_root = utils_get_directory(app_path);
+ if (app_root == NULL)
+ {
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ hostfxr_resolver_t fxr;
+ hostfxr_resolver_init(&fxr, app_root);
+
+ int rc = fxr.status_code;
+ if (rc != Success)
+ {
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+ }
+
+ if (is_bundle)
+ {
+ hostfxr_main_bundle_startupinfo_fn hostfxr_main_bundle_startupinfo = hostfxr_resolver_resolve_main_bundle_startupinfo(&fxr);
+ if (hostfxr_main_bundle_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+ int64_t bundle_header_offset = bundle_marker_header_offset();
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_bundle_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+ trace_info(_X("Bundle Header Offset: [%" PRId64 "]"), bundle_header_offset);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+ rc = hostfxr_main_bundle_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr, bundle_header_offset);
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not support single-file apps."), fxr.fxr_path);
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ rc = FrameworkMissingFailure;
+ }
+ }
+ else
+ {
+ hostfxr_main_startupinfo_fn hostfxr_main_startupinfo = hostfxr_resolver_resolve_main_startupinfo(&fxr);
+ if (hostfxr_main_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+
+ rc = hostfxr_main_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr);
+
+ if (trace_get_error_writer() != NULL && rc == (int)FrameworkMissingFailure && set_error_writer == NULL)
+ {
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ }
+
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+#if !defined(FEATURE_STATIC_HOST)
+ else
+ {
+ if (requires_hostfxr_startupinfo_interface)
+ {
+ trace_error(_X("The required library %s does not support relative app dll paths."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ else
+ {
+ trace_info(_X("Invoking fx resolver [%s] v1"), fxr.fxr_path);
+
+ // Previous corehost trace messages must be printed before calling trace::setup in hostfxr
+ trace_flush();
+
+ hostfxr_main_fn main_fn_v1 = hostfxr_resolver_resolve_main_v1(&fxr);
+ if (main_fn_v1 != NULL)
+ {
+ rc = main_fn_v1(argc, argv);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not contain the expected entry point."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ }
+ }
+#endif // !defined(FEATURE_STATIC_HOST)
+ }
+
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+}
+
+#if defined(_WIN32)
+int __cdecl wmain(int argc, const pal_char_t* argv[])
+#else
+int main(const int argc, const pal_char_t* argv[])
+#endif
+{
+ trace_setup();
+
+ if (trace_is_enabled())
+ {
+ trace_info(_X("--- Invoked apphost [version: ")
+#if defined(_WIN32)
+ _STRINGIFY(VER_PRODUCTVERSION_STR)
+#else
+ _STRINGIFY(HOST_VERSION) _X(" @Commit: ") _STRINGIFY(REPO_COMMIT_HASH)
+#endif
+ _X("] main = {"));
+ for (int i = 0; i < argc; ++i)
+ {
+ trace_info(_X("%s"), argv[i]);
+ }
+ trace_info(_X("}"));
+ }
+
+#if defined(_WIN32)
+ apphost_buffer_errors();
+#endif
+
+ int exit_code = exe_start(argc, argv);
+
+ trace_flush();
+
+#if defined(_WIN32)
+ apphost_write_buffered_errors(exit_code);
+#endif
+
+ return exit_code;
+}

src/native/corehost/apphost/apphost.c

@@ -0,0 +1,389 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#include "pal.h"
+#include "trace.h"
+#include "utils.h"
+#include "bundle_marker.h"
+#include "apphost_hostfxr_resolver.h"
+#include "error_codes.h"
+#include "hostfxr.h"
+
+#if defined(_WIN32)
+#include "apphost.windows.h"
+#include <_version.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+#if defined(FEATURE_STATIC_HOST)
+extern void apphost_static_init(void);
+#endif
+
+/**
+ * Detect if the apphost executable is allowed to load and execute a managed assembly.
+ *
+ * - The exe is built with a known hash string at some offset in the image
+ * - The exe is useless as is with the built-in hash value, and will fail with an error message
+ * - The hash value should be replaced with the managed DLL filename with optional relative path
+ * - The optional path is relative to the location of the apphost executable
+ * - The relative path plus filename are verified to reference a valid file
+ * - The filename should be "NUL terminated UTF-8" by "dotnet build"
+ * - The managed DLL filename does not have to be the same name as the apphost executable name
+ * - The exe may be signed at this point by the app publisher
+ * - Note: the maximum size of the filename and relative path is 1024 bytes in UTF-8 (not including NUL)
+ * o https://en.wikipedia.org/wiki/Comparison_of_file_systems
+ * has more details on maximum file name sizes.
+ */
+#define EMBED_HASH_HI_PART_UTF8 "c3ab8ff13720e8ad9047dd39466b3c89" // SHA-256 of "foobar" in UTF-8
+#define EMBED_HASH_LO_PART_UTF8 "74e592c2fa383d4a3960714caef0c4f2"
+#define EMBED_HASH_FULL_UTF8 (EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8) // NUL terminated
+
+#define EMBED_SZ (int)(sizeof(EMBED_HASH_FULL_UTF8) / sizeof(EMBED_HASH_FULL_UTF8[0]))
+#define EMBED_MAX (EMBED_SZ > 1025 ? EMBED_SZ : 1025) // 1024 DLL name length, 1 NUL
+
+// This avoids compiler optimization which cause EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8
+// to be placed adjacent causing them to match EMBED_HASH_FULL_UTF8 when searched for replacing.
+// See https://github.com/dotnet/runtime/issues/109611 for more details.
+static bool compare_memory_nooptimization(volatile const char* a, volatile const char* b, size_t length)
+{
+ for (size_t i = 0; i < length; i++)
+ {
+ if (*a++ != *b++)
+ return false;
+ }
+ return true;
+}
+
+// app_dll receives the embedded DLL name as a pal_char_t string.
+// app_dll_len is the buffer size in pal_char_t characters.
+static bool is_exe_enabled_for_execution(pal_char_t* app_dll, size_t app_dll_len)
+{
+ // Contains the EMBED_HASH_FULL_UTF8 value at compile time or the managed DLL name replaced by "dotnet build".
+ // Must not be 'const' because strlen below could be determined at compile time (=64) instead of the actual
+ // length of the string at runtime.
+ // Always narrow UTF-8, regardless of platform.
+ static char embed[EMBED_MAX] = EMBED_HASH_FULL_UTF8;
+
+ static const char hi_part[] = EMBED_HASH_HI_PART_UTF8;
+ static const char lo_part[] = EMBED_HASH_LO_PART_UTF8;
+
+ size_t binding_len = strlen(&embed[0]);
+
+ if (binding_len == 0 || binding_len >= app_dll_len)
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ // Check if the path exceeds the max allowed size
+ if (binding_len > EMBED_MAX - 1)
+ {
+ trace_error(_X("The managed DLL bound to this executable is longer than the max allowed length (%d)"), EMBED_MAX - 1);
+ return false;
+ }
+
+ // Check if the value is the same as the placeholder to detect unbound executables
+ size_t hi_len = sizeof(hi_part) - 1;
+ size_t lo_len = sizeof(lo_part) - 1;
+ if (binding_len >= (hi_len + lo_len)
+ && compare_memory_nooptimization(&embed[0], hi_part, hi_len)
+ && compare_memory_nooptimization(&embed[hi_len], lo_part, lo_len))
+ {
+ trace_error(_X("This executable is not bound to a managed DLL to execute."));
+ return false;
+ }
+
+ if (!pal_utf8_to_palstr(&embed[0], app_dll, app_dll_len))
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ trace_info(_X("The managed DLL bound to this executable is: '%s'"), app_dll);
+ return true;
+}
+
+static void report_outdated_framework_error(const pal_char_t* dotnet_root, const pal_char_t* host_path)
+{
+ pal_char_t download_url[MAX_DOWNLOAD_URL_LEN];
+ utils_get_download_url(download_url, ARRAY_SIZE(download_url), NULL, NULL);
+
+ trace_error(
+ MISSING_RUNTIME_ERROR_FORMAT,
+ INSTALL_OR_UPDATE_NET_ERROR_MESSAGE,
+ host_path,
+ _STRINGIFY(CURRENT_ARCH_NAME),
+ _STRINGIFY(HOST_VERSION),
+ dotnet_root,
+ download_url,
+ _STRINGIFY(HOST_VERSION));
+}
+
+// C equivalent of propagate_error_writer_t
+typedef struct {
+ hostfxr_set_error_writer_fn set_error_writer;
+ bool error_writer_set;
+} propagate_error_writer_state_t;
+
+static void propagate_error_writer_init(propagate_error_writer_state_t* state, hostfxr_set_error_writer_fn set_error_writer)
+{
+ trace_flush();
+
+ state->set_error_writer = set_error_writer;
+ state->error_writer_set = false;
+
+ trace_error_writer_fn error_writer = trace_get_error_writer();
+ if (error_writer != NULL && set_error_writer != NULL)
+ {
+ set_error_writer((hostfxr_error_writer_fn)error_writer);
+ state->error_writer_set = true;
+ }
+}
+
+static void propagate_error_writer_cleanup(propagate_error_writer_state_t* state)
+{
+ if (state->error_writer_set && state->set_error_writer != NULL)
+ {
+ state->set_error_writer(NULL);
+ state->error_writer_set = false;
+ }
+}
+
+static int exe_start(const int argc, const pal_char_t* argv[])
+{
+#if defined(FEATURE_STATIC_HOST)
+ apphost_static_init();
+#endif
+
+ // Use realpath/GetModuleFileName to find the path of the host, resolving any symlinks.
+ pal_char_t* host_path = pal_get_own_executable_path();
+ if (host_path == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), _X("<unknown>"));
+ return CurrentHostFindFailure;
+ }
+
+ pal_char_t* host_path_full = pal_fullpath(host_path, false);
+ if (host_path_full == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), host_path);
+ free(host_path);
+ return CurrentHostFindFailure;
+ }
+
+ free(host_path);
+ host_path = host_path_full;
+
+ bool requires_hostfxr_startupinfo_interface = false;
+
+ // FEATURE_APPHOST path: read embedded DLL name
+ pal_char_t embedded_app_name[EMBED_MAX];
+ if (!is_exe_enabled_for_execution(embedded_app_name, ARRAY_SIZE(embedded_app_name)))
+ {
+ free(host_path);
+ return AppHostExeNotBoundFailure;
+ }
+
+#if defined(_WIN32)
+ for (pal_char_t* c = embedded_app_name; *c != _X('\0'); c++)
+ {
+ if (*c == _X('/'))
+ *c = DIR_SEPARATOR;
+ }
+#endif
+
+ if (pal_strchr(embedded_app_name, DIR_SEPARATOR) != NULL)
+ {
+ requires_hostfxr_startupinfo_interface = true;
+ }
+
+ pal_char_t* app_dir = utils_get_directory(host_path);
+ if (app_dir == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ pal_char_t* app_path = utils_append_path_alloc(app_dir, embedded_app_name);
+ free(app_dir);
+ if (app_path == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ const bool is_bundle = bundle_marker_is_bundle();
+ if (is_bundle)
+ {
+ trace_info(_X("Detected Single-File app bundle"));
+ }
+ else
+ {
+ pal_char_t* app_path_full = pal_fullpath(app_path, false);
+ if (app_path_full == NULL)
+ {
+ trace_error(_X("The application to execute does not exist: '%s'."), app_path);
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ free(app_path);
+ app_path = app_path_full;
+ }
+
+ pal_char_t* app_root = utils_get_directory(app_path);
+ if (app_root == NULL)
+ {
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ hostfxr_resolver_t fxr;
+ hostfxr_resolver_init(&fxr, app_root);
+
+ int rc = fxr.status_code;
+ if (rc != Success)
+ {
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+ }
+
+ if (is_bundle)
+ {
+ hostfxr_main_bundle_startupinfo_fn hostfxr_main_bundle_startupinfo = hostfxr_resolver_resolve_main_bundle_startupinfo(&fxr);
+ if (hostfxr_main_bundle_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+ int64_t bundle_header_offset = bundle_marker_header_offset();
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_bundle_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+ trace_info(_X("Bundle Header Offset: [%" PRId64 "]"), bundle_header_offset);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+ rc = hostfxr_main_bundle_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr, bundle_header_offset);
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not support single-file apps."), fxr.fxr_path);
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ rc = FrameworkMissingFailure;
+ }
+ }
+ else
+ {
+ hostfxr_main_startupinfo_fn hostfxr_main_startupinfo = hostfxr_resolver_resolve_main_startupinfo(&fxr);
+ if (hostfxr_main_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+
+ rc = hostfxr_main_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr);
+
+ if (trace_get_error_writer() != NULL && rc == (int)FrameworkMissingFailure && set_error_writer == NULL)
+ {
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ }
+
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+#if !defined(FEATURE_STATIC_HOST)
+ else
+ {
+ if (requires_hostfxr_startupinfo_interface)
+ {
+ trace_error(_X("The required library %s does not support relative app dll paths."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ else
+ {
+ trace_info(_X("Invoking fx resolver [%s] v1"), fxr.fxr_path);
+
+ // Previous corehost trace messages must be printed before calling trace::setup in hostfxr
+ trace_flush();
+
+ hostfxr_main_fn main_fn_v1 = hostfxr_resolver_resolve_main_v1(&fxr);
+ if (main_fn_v1 != NULL)
+ {
+ rc = main_fn_v1(argc, argv);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not contain the expected entry point."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ }
+ }
+#endif // !defined(FEATURE_STATIC_HOST)
+ }
+
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+}
+
+#if defined(_WIN32)
+int __cdecl wmain(int argc, const pal_char_t* argv[])
+#else
+int main(const int argc, const pal_char_t* argv[])
+#endif
+{
+ trace_setup();
+
+ if (trace_is_enabled())
+ {
+ trace_info(_X("--- Invoked apphost [version: ")
+#if defined(_WIN32)
+ _STRINGIFY(VER_PRODUCTVERSION_STR)
+#else
+ _STRINGIFY(HOST_VERSION) _X(" @Commit: ") _STRINGIFY(REPO_COMMIT_HASH)
+#endif
+ _X("] main = {"));
+ for (int i = 0; i < argc; ++i)
+ {
+ trace_info(_X("%s"), argv[i]);
+ }
+ trace_info(_X("}"));
+ }
+
+#if defined(_WIN32)
+ apphost_buffer_errors();
+#endif
+
+ int exit_code = exe_start(argc, argv);
+
+ trace_flush();
+
+#if defined(_WIN32)
+ apphost_write_buffered_errors(exit_code);
+#endif
+
+ return exit_code;
+}

src/native/corehost/apphost/apphost.c

@@ -0,0 +1,389 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#include "pal.h"
+#include "trace.h"
+#include "utils.h"
+#include "bundle_marker.h"
+#include "apphost_hostfxr_resolver.h"
+#include "error_codes.h"
+#include "hostfxr.h"
+
+#if defined(_WIN32)
+#include "apphost.windows.h"
+#include <_version.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+#if defined(FEATURE_STATIC_HOST)
+extern void apphost_static_init(void);
+#endif
+
+/**
+ * Detect if the apphost executable is allowed to load and execute a managed assembly.
+ *
+ * - The exe is built with a known hash string at some offset in the image
+ * - The exe is useless as is with the built-in hash value, and will fail with an error message
+ * - The hash value should be replaced with the managed DLL filename with optional relative path
+ * - The optional path is relative to the location of the apphost executable
+ * - The relative path plus filename are verified to reference a valid file
+ * - The filename should be "NUL terminated UTF-8" by "dotnet build"
+ * - The managed DLL filename does not have to be the same name as the apphost executable name
+ * - The exe may be signed at this point by the app publisher
+ * - Note: the maximum size of the filename and relative path is 1024 bytes in UTF-8 (not including NUL)
+ * o https://en.wikipedia.org/wiki/Comparison_of_file_systems
+ * has more details on maximum file name sizes.
+ */
+#define EMBED_HASH_HI_PART_UTF8 "c3ab8ff13720e8ad9047dd39466b3c89" // SHA-256 of "foobar" in UTF-8
+#define EMBED_HASH_LO_PART_UTF8 "74e592c2fa383d4a3960714caef0c4f2"
+#define EMBED_HASH_FULL_UTF8 (EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8) // NUL terminated
+
+#define EMBED_SZ (int)(sizeof(EMBED_HASH_FULL_UTF8) / sizeof(EMBED_HASH_FULL_UTF8[0]))
+#define EMBED_MAX (EMBED_SZ > 1025 ? EMBED_SZ : 1025) // 1024 DLL name length, 1 NUL
+
+// This avoids compiler optimization which cause EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8
+// to be placed adjacent causing them to match EMBED_HASH_FULL_UTF8 when searched for replacing.
+// See https://github.com/dotnet/runtime/issues/109611 for more details.
+static bool compare_memory_nooptimization(volatile const char* a, volatile const char* b, size_t length)
+{
+ for (size_t i = 0; i < length; i++)
+ {
+ if (*a++ != *b++)
+ return false;
+ }
+ return true;
+}
+
+// app_dll receives the embedded DLL name as a pal_char_t string.
+// app_dll_len is the buffer size in pal_char_t characters.
+static bool is_exe_enabled_for_execution(pal_char_t* app_dll, size_t app_dll_len)
+{
+ // Contains the EMBED_HASH_FULL_UTF8 value at compile time or the managed DLL name replaced by "dotnet build".
+ // Must not be 'const' because strlen below could be determined at compile time (=64) instead of the actual
+ // length of the string at runtime.
+ // Always narrow UTF-8, regardless of platform.
+ static char embed[EMBED_MAX] = EMBED_HASH_FULL_UTF8;
+
+ static const char hi_part[] = EMBED_HASH_HI_PART_UTF8;
+ static const char lo_part[] = EMBED_HASH_LO_PART_UTF8;
+
+ size_t binding_len = strlen(&embed[0]);
+
+ if (binding_len == 0 || binding_len >= app_dll_len)
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ // Check if the path exceeds the max allowed size
+ if (binding_len > EMBED_MAX - 1)
+ {
+ trace_error(_X("The managed DLL bound to this executable is longer than the max allowed length (%d)"), EMBED_MAX - 1);
+ return false;
+ }
+
+ // Check if the value is the same as the placeholder to detect unbound executables
+ size_t hi_len = sizeof(hi_part) - 1;
+ size_t lo_len = sizeof(lo_part) - 1;
+ if (binding_len >= (hi_len + lo_len)
+ && compare_memory_nooptimization(&embed[0], hi_part, hi_len)
+ && compare_memory_nooptimization(&embed[hi_len], lo_part, lo_len))
+ {
+ trace_error(_X("This executable is not bound to a managed DLL to execute."));
+ return false;
+ }
+
+ if (!pal_utf8_to_palstr(&embed[0], app_dll, app_dll_len))
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ trace_info(_X("The managed DLL bound to this executable is: '%s'"), app_dll);
+ return true;
+}
+
+static void report_outdated_framework_error(const pal_char_t* dotnet_root, const pal_char_t* host_path)
+{
+ pal_char_t download_url[MAX_DOWNLOAD_URL_LEN];
+ utils_get_download_url(download_url, ARRAY_SIZE(download_url), NULL, NULL);
+
+ trace_error(
+ MISSING_RUNTIME_ERROR_FORMAT,
+ INSTALL_OR_UPDATE_NET_ERROR_MESSAGE,
+ host_path,
+ _STRINGIFY(CURRENT_ARCH_NAME),
+ _STRINGIFY(HOST_VERSION),
+ dotnet_root,
+ download_url,
+ _STRINGIFY(HOST_VERSION));
+}
+
+// C equivalent of propagate_error_writer_t
+typedef struct {
+ hostfxr_set_error_writer_fn set_error_writer;
+ bool error_writer_set;
+} propagate_error_writer_state_t;
+
+static void propagate_error_writer_init(propagate_error_writer_state_t* state, hostfxr_set_error_writer_fn set_error_writer)
+{
+ trace_flush();
+
+ state->set_error_writer = set_error_writer;
+ state->error_writer_set = false;
+
+ trace_error_writer_fn error_writer = trace_get_error_writer();
+ if (error_writer != NULL && set_error_writer != NULL)
+ {
+ set_error_writer((hostfxr_error_writer_fn)error_writer);
+ state->error_writer_set = true;
+ }
+}
+
+static void propagate_error_writer_cleanup(propagate_error_writer_state_t* state)
+{
+ if (state->error_writer_set && state->set_error_writer != NULL)
+ {
+ state->set_error_writer(NULL);
+ state->error_writer_set = false;
+ }
+}
+
+static int exe_start(const int argc, const pal_char_t* argv[])
+{
+#if defined(FEATURE_STATIC_HOST)
+ apphost_static_init();
+#endif
+
+ // Use realpath/GetModuleFileName to find the path of the host, resolving any symlinks.
+ pal_char_t* host_path = pal_get_own_executable_path();
+ if (host_path == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), _X("<unknown>"));
+ return CurrentHostFindFailure;
+ }
+
+ pal_char_t* host_path_full = pal_fullpath(host_path, false);
+ if (host_path_full == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), host_path);
+ free(host_path);
+ return CurrentHostFindFailure;
+ }
+
+ free(host_path);
+ host_path = host_path_full;
+
+ bool requires_hostfxr_startupinfo_interface = false;
+
+ // FEATURE_APPHOST path: read embedded DLL name
+ pal_char_t embedded_app_name[EMBED_MAX];
+ if (!is_exe_enabled_for_execution(embedded_app_name, ARRAY_SIZE(embedded_app_name)))
+ {
+ free(host_path);
+ return AppHostExeNotBoundFailure;
+ }
+
+#if defined(_WIN32)
+ for (pal_char_t* c = embedded_app_name; *c != _X('\0'); c++)
+ {
+ if (*c == _X('/'))
+ *c = DIR_SEPARATOR;
+ }
+#endif
+
+ if (pal_strchr(embedded_app_name, DIR_SEPARATOR) != NULL)
+ {
+ requires_hostfxr_startupinfo_interface = true;
+ }
+
+ pal_char_t* app_dir = utils_get_directory(host_path);
+ if (app_dir == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ pal_char_t* app_path = utils_append_path_alloc(app_dir, embedded_app_name);
+ free(app_dir);
+ if (app_path == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ const bool is_bundle = bundle_marker_is_bundle();
+ if (is_bundle)
+ {
+ trace_info(_X("Detected Single-File app bundle"));
+ }
+ else
+ {
+ pal_char_t* app_path_full = pal_fullpath(app_path, false);
+ if (app_path_full == NULL)
+ {
+ trace_error(_X("The application to execute does not exist: '%s'."), app_path);
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ free(app_path);
+ app_path = app_path_full;
+ }
+
+ pal_char_t* app_root = utils_get_directory(app_path);
+ if (app_root == NULL)
+ {
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ hostfxr_resolver_t fxr;
+ hostfxr_resolver_init(&fxr, app_root);
+
+ int rc = fxr.status_code;
+ if (rc != Success)
+ {
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+ }
+
+ if (is_bundle)
+ {
+ hostfxr_main_bundle_startupinfo_fn hostfxr_main_bundle_startupinfo = hostfxr_resolver_resolve_main_bundle_startupinfo(&fxr);
+ if (hostfxr_main_bundle_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+ int64_t bundle_header_offset = bundle_marker_header_offset();
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_bundle_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+ trace_info(_X("Bundle Header Offset: [%" PRId64 "]"), bundle_header_offset);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+ rc = hostfxr_main_bundle_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr, bundle_header_offset);
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not support single-file apps."), fxr.fxr_path);
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ rc = FrameworkMissingFailure;
+ }
+ }
+ else
+ {
+ hostfxr_main_startupinfo_fn hostfxr_main_startupinfo = hostfxr_resolver_resolve_main_startupinfo(&fxr);
+ if (hostfxr_main_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+
+ rc = hostfxr_main_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr);
+
+ if (trace_get_error_writer() != NULL && rc == (int)FrameworkMissingFailure && set_error_writer == NULL)
+ {
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ }
+
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+#if !defined(FEATURE_STATIC_HOST)
+ else
+ {
+ if (requires_hostfxr_startupinfo_interface)
+ {
+ trace_error(_X("The required library %s does not support relative app dll paths."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ else
+ {
+ trace_info(_X("Invoking fx resolver [%s] v1"), fxr.fxr_path);
+
+ // Previous corehost trace messages must be printed before calling trace::setup in hostfxr
+ trace_flush();
+
+ hostfxr_main_fn main_fn_v1 = hostfxr_resolver_resolve_main_v1(&fxr);
+ if (main_fn_v1 != NULL)
+ {
+ rc = main_fn_v1(argc, argv);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not contain the expected entry point."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ }
+ }
+#endif // !defined(FEATURE_STATIC_HOST)
+ }
+
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+}
+
+#if defined(_WIN32)
+int __cdecl wmain(int argc, const pal_char_t* argv[])
+#else
+int main(const int argc, const pal_char_t* argv[])
+#endif
+{
+ trace_setup();
+
+ if (trace_is_enabled())
+ {
+ trace_info(_X("--- Invoked apphost [version: ")
+#if defined(_WIN32)
+ _STRINGIFY(VER_PRODUCTVERSION_STR)
+#else
+ _STRINGIFY(HOST_VERSION) _X(" @Commit: ") _STRINGIFY(REPO_COMMIT_HASH)
+#endif
+ _X("] main = {"));
+ for (int i = 0; i < argc; ++i)
+ {
+ trace_info(_X("%s"), argv[i]);
+ }
+ trace_info(_X("}"));
+ }
+
+#if defined(_WIN32)
+ apphost_buffer_errors();
+#endif
+
+ int exit_code = exe_start(argc, argv);
+
+ trace_flush();
+
+#if defined(_WIN32)
+ apphost_write_buffered_errors(exit_code);
+#endif
+
+ return exit_code;
+}

src/native/corehost/apphost/apphost.c

@@ -0,0 +1,389 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#include "pal.h"
+#include "trace.h"
+#include "utils.h"
+#include "bundle_marker.h"
+#include "apphost_hostfxr_resolver.h"
+#include "error_codes.h"
+#include "hostfxr.h"
+
+#if defined(_WIN32)
+#include "apphost.windows.h"
+#include <_version.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+#if defined(FEATURE_STATIC_HOST)
+extern void apphost_static_init(void);
+#endif
+
+/**
+ * Detect if the apphost executable is allowed to load and execute a managed assembly.
+ *
+ * - The exe is built with a known hash string at some offset in the image
+ * - The exe is useless as is with the built-in hash value, and will fail with an error message
+ * - The hash value should be replaced with the managed DLL filename with optional relative path
+ * - The optional path is relative to the location of the apphost executable
+ * - The relative path plus filename are verified to reference a valid file
+ * - The filename should be "NUL terminated UTF-8" by "dotnet build"
+ * - The managed DLL filename does not have to be the same name as the apphost executable name
+ * - The exe may be signed at this point by the app publisher
+ * - Note: the maximum size of the filename and relative path is 1024 bytes in UTF-8 (not including NUL)
+ * o https://en.wikipedia.org/wiki/Comparison_of_file_systems
+ * has more details on maximum file name sizes.
+ */
+#define EMBED_HASH_HI_PART_UTF8 "c3ab8ff13720e8ad9047dd39466b3c89" // SHA-256 of "foobar" in UTF-8
+#define EMBED_HASH_LO_PART_UTF8 "74e592c2fa383d4a3960714caef0c4f2"
+#define EMBED_HASH_FULL_UTF8 (EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8) // NUL terminated
+
+#define EMBED_SZ (int)(sizeof(EMBED_HASH_FULL_UTF8) / sizeof(EMBED_HASH_FULL_UTF8[0]))
+#define EMBED_MAX (EMBED_SZ > 1025 ? EMBED_SZ : 1025) // 1024 DLL name length, 1 NUL
+
+// This avoids compiler optimization which cause EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8
+// to be placed adjacent causing them to match EMBED_HASH_FULL_UTF8 when searched for replacing.
+// See https://github.com/dotnet/runtime/issues/109611 for more details.
+static bool compare_memory_nooptimization(volatile const char* a, volatile const char* b, size_t length)
+{
+ for (size_t i = 0; i < length; i++)
+ {
+ if (*a++ != *b++)
+ return false;
+ }
+ return true;
+}
+
+// app_dll receives the embedded DLL name as a pal_char_t string.
+// app_dll_len is the buffer size in pal_char_t characters.
+static bool is_exe_enabled_for_execution(pal_char_t* app_dll, size_t app_dll_len)
+{
+ // Contains the EMBED_HASH_FULL_UTF8 value at compile time or the managed DLL name replaced by "dotnet build".
+ // Must not be 'const' because strlen below could be determined at compile time (=64) instead of the actual
+ // length of the string at runtime.
+ // Always narrow UTF-8, regardless of platform.
+ static char embed[EMBED_MAX] = EMBED_HASH_FULL_UTF8;
+
+ static const char hi_part[] = EMBED_HASH_HI_PART_UTF8;
+ static const char lo_part[] = EMBED_HASH_LO_PART_UTF8;
+
+ size_t binding_len = strlen(&embed[0]);
+
+ if (binding_len == 0 || binding_len >= app_dll_len)
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ // Check if the path exceeds the max allowed size
+ if (binding_len > EMBED_MAX - 1)
+ {
+ trace_error(_X("The managed DLL bound to this executable is longer than the max allowed length (%d)"), EMBED_MAX - 1);
+ return false;
+ }
+
+ // Check if the value is the same as the placeholder to detect unbound executables
+ size_t hi_len = sizeof(hi_part) - 1;
+ size_t lo_len = sizeof(lo_part) - 1;
+ if (binding_len >= (hi_len + lo_len)
+ && compare_memory_nooptimization(&embed[0], hi_part, hi_len)
+ && compare_memory_nooptimization(&embed[hi_len], lo_part, lo_len))
+ {
+ trace_error(_X("This executable is not bound to a managed DLL to execute."));
+ return false;
+ }
+
+ if (!pal_utf8_to_palstr(&embed[0], app_dll, app_dll_len))
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ trace_info(_X("The managed DLL bound to this executable is: '%s'"), app_dll);
+ return true;
+}
+
+static void report_outdated_framework_error(const pal_char_t* dotnet_root, const pal_char_t* host_path)
+{
+ pal_char_t download_url[MAX_DOWNLOAD_URL_LEN];
+ utils_get_download_url(download_url, ARRAY_SIZE(download_url), NULL, NULL);
+
+ trace_error(
+ MISSING_RUNTIME_ERROR_FORMAT,
+ INSTALL_OR_UPDATE_NET_ERROR_MESSAGE,
+ host_path,
+ _STRINGIFY(CURRENT_ARCH_NAME),
+ _STRINGIFY(HOST_VERSION),
+ dotnet_root,
+ download_url,
+ _STRINGIFY(HOST_VERSION));
+}
+
+// C equivalent of propagate_error_writer_t
+typedef struct {
+ hostfxr_set_error_writer_fn set_error_writer;
+ bool error_writer_set;
+} propagate_error_writer_state_t;
+
+static void propagate_error_writer_init(propagate_error_writer_state_t* state, hostfxr_set_error_writer_fn set_error_writer)
+{
+ trace_flush();
+
+ state->set_error_writer = set_error_writer;
+ state->error_writer_set = false;
+
+ trace_error_writer_fn error_writer = trace_get_error_writer();
+ if (error_writer != NULL && set_error_writer != NULL)
+ {
+ set_error_writer((hostfxr_error_writer_fn)error_writer);
+ state->error_writer_set = true;
+ }
+}
+
+static void propagate_error_writer_cleanup(propagate_error_writer_state_t* state)
+{
+ if (state->error_writer_set && state->set_error_writer != NULL)
+ {
+ state->set_error_writer(NULL);
+ state->error_writer_set = false;
+ }
+}
+
+static int exe_start(const int argc, const pal_char_t* argv[])
+{
+#if defined(FEATURE_STATIC_HOST)
+ apphost_static_init();
+#endif
+
+ // Use realpath/GetModuleFileName to find the path of the host, resolving any symlinks.
+ pal_char_t* host_path = pal_get_own_executable_path();
+ if (host_path == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), _X("<unknown>"));
+ return CurrentHostFindFailure;
+ }
+
+ pal_char_t* host_path_full = pal_fullpath(host_path, false);
+ if (host_path_full == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), host_path);
+ free(host_path);
+ return CurrentHostFindFailure;
+ }
+
+ free(host_path);
+ host_path = host_path_full;
+
+ bool requires_hostfxr_startupinfo_interface = false;
+
+ // FEATURE_APPHOST path: read embedded DLL name
+ pal_char_t embedded_app_name[EMBED_MAX];
+ if (!is_exe_enabled_for_execution(embedded_app_name, ARRAY_SIZE(embedded_app_name)))
+ {
+ free(host_path);
+ return AppHostExeNotBoundFailure;
+ }
+
+#if defined(_WIN32)
+ for (pal_char_t* c = embedded_app_name; *c != _X('\0'); c++)
+ {
+ if (*c == _X('/'))
+ *c = DIR_SEPARATOR;
+ }
+#endif
+
+ if (pal_strchr(embedded_app_name, DIR_SEPARATOR) != NULL)
+ {
+ requires_hostfxr_startupinfo_interface = true;
+ }
+
+ pal_char_t* app_dir = utils_get_directory(host_path);
+ if (app_dir == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ pal_char_t* app_path = utils_append_path_alloc(app_dir, embedded_app_name);
+ free(app_dir);
+ if (app_path == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ const bool is_bundle = bundle_marker_is_bundle();
+ if (is_bundle)
+ {
+ trace_info(_X("Detected Single-File app bundle"));
+ }
+ else
+ {
+ pal_char_t* app_path_full = pal_fullpath(app_path, false);
+ if (app_path_full == NULL)
+ {
+ trace_error(_X("The application to execute does not exist: '%s'."), app_path);
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ free(app_path);
+ app_path = app_path_full;
+ }
+
+ pal_char_t* app_root = utils_get_directory(app_path);
+ if (app_root == NULL)
+ {
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ hostfxr_resolver_t fxr;
+ hostfxr_resolver_init(&fxr, app_root);
+
+ int rc = fxr.status_code;
+ if (rc != Success)
+ {
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+ }
+
+ if (is_bundle)
+ {
+ hostfxr_main_bundle_startupinfo_fn hostfxr_main_bundle_startupinfo = hostfxr_resolver_resolve_main_bundle_startupinfo(&fxr);
+ if (hostfxr_main_bundle_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+ int64_t bundle_header_offset = bundle_marker_header_offset();
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_bundle_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+ trace_info(_X("Bundle Header Offset: [%" PRId64 "]"), bundle_header_offset);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+ rc = hostfxr_main_bundle_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr, bundle_header_offset);
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not support single-file apps."), fxr.fxr_path);
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ rc = FrameworkMissingFailure;
+ }
+ }
+ else
+ {
+ hostfxr_main_startupinfo_fn hostfxr_main_startupinfo = hostfxr_resolver_resolve_main_startupinfo(&fxr);
+ if (hostfxr_main_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+
+ rc = hostfxr_main_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr);
+
+ if (trace_get_error_writer() != NULL && rc == (int)FrameworkMissingFailure && set_error_writer == NULL)
+ {
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ }
+
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+#if !defined(FEATURE_STATIC_HOST)
+ else
+ {
+ if (requires_hostfxr_startupinfo_interface)
+ {
+ trace_error(_X("The required library %s does not support relative app dll paths."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ else
+ {
+ trace_info(_X("Invoking fx resolver [%s] v1"), fxr.fxr_path);
+
+ // Previous corehost trace messages must be printed before calling trace::setup in hostfxr
+ trace_flush();
+
+ hostfxr_main_fn main_fn_v1 = hostfxr_resolver_resolve_main_v1(&fxr);
+ if (main_fn_v1 != NULL)
+ {
+ rc = main_fn_v1(argc, argv);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not contain the expected entry point."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ }
+ }
+#endif // !defined(FEATURE_STATIC_HOST)
+ }
+
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+}
+
+#if defined(_WIN32)
+int __cdecl wmain(int argc, const pal_char_t* argv[])
+#else
+int main(const int argc, const pal_char_t* argv[])
+#endif
+{
+ trace_setup();
+
+ if (trace_is_enabled())
+ {
+ trace_info(_X("--- Invoked apphost [version: ")
+#if defined(_WIN32)
+ _STRINGIFY(VER_PRODUCTVERSION_STR)
+#else
+ _STRINGIFY(HOST_VERSION) _X(" @Commit: ") _STRINGIFY(REPO_COMMIT_HASH)
+#endif
+ _X("] main = {"));
+ for (int i = 0; i < argc; ++i)
+ {
+ trace_info(_X("%s"), argv[i]);
+ }
+ trace_info(_X("}"));
+ }
+
+#if defined(_WIN32)
+ apphost_buffer_errors();
+#endif
+
+ int exit_code = exe_start(argc, argv);
+
+ trace_flush();
+
+#if defined(_WIN32)
+ apphost_write_buffered_errors(exit_code);
+#endif
+
+ return exit_code;
+}

src/native/corehost/apphost/apphost.c

@@ -0,0 +1,389 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#include "pal.h"
+#include "trace.h"
+#include "utils.h"
+#include "bundle_marker.h"
+#include "apphost_hostfxr_resolver.h"
+#include "error_codes.h"
+#include "hostfxr.h"
+
+#if defined(_WIN32)
+#include "apphost.windows.h"
+#include <_version.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+#if defined(FEATURE_STATIC_HOST)
+extern void apphost_static_init(void);
+#endif
+
+/**
+ * Detect if the apphost executable is allowed to load and execute a managed assembly.
+ *
+ * - The exe is built with a known hash string at some offset in the image
+ * - The exe is useless as is with the built-in hash value, and will fail with an error message
+ * - The hash value should be replaced with the managed DLL filename with optional relative path
+ * - The optional path is relative to the location of the apphost executable
+ * - The relative path plus filename are verified to reference a valid file
+ * - The filename should be "NUL terminated UTF-8" by "dotnet build"
+ * - The managed DLL filename does not have to be the same name as the apphost executable name
+ * - The exe may be signed at this point by the app publisher
+ * - Note: the maximum size of the filename and relative path is 1024 bytes in UTF-8 (not including NUL)
+ * o https://en.wikipedia.org/wiki/Comparison_of_file_systems
+ * has more details on maximum file name sizes.
+ */
+#define EMBED_HASH_HI_PART_UTF8 "c3ab8ff13720e8ad9047dd39466b3c89" // SHA-256 of "foobar" in UTF-8
+#define EMBED_HASH_LO_PART_UTF8 "74e592c2fa383d4a3960714caef0c4f2"
+#define EMBED_HASH_FULL_UTF8 (EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8) // NUL terminated
+
+#define EMBED_SZ (int)(sizeof(EMBED_HASH_FULL_UTF8) / sizeof(EMBED_HASH_FULL_UTF8[0]))
+#define EMBED_MAX (EMBED_SZ > 1025 ? EMBED_SZ : 1025) // 1024 DLL name length, 1 NUL
+
+// This avoids compiler optimization which cause EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8
+// to be placed adjacent causing them to match EMBED_HASH_FULL_UTF8 when searched for replacing.
+// See https://github.com/dotnet/runtime/issues/109611 for more details.
+static bool compare_memory_nooptimization(volatile const char* a, volatile const char* b, size_t length)
+{
+ for (size_t i = 0; i < length; i++)
+ {
+ if (*a++ != *b++)
+ return false;
+ }
+ return true;
+}
+
+// app_dll receives the embedded DLL name as a pal_char_t string.
+// app_dll_len is the buffer size in pal_char_t characters.
+static bool is_exe_enabled_for_execution(pal_char_t* app_dll, size_t app_dll_len)
+{
+ // Contains the EMBED_HASH_FULL_UTF8 value at compile time or the managed DLL name replaced by "dotnet build".
+ // Must not be 'const' because strlen below could be determined at compile time (=64) instead of the actual
+ // length of the string at runtime.
+ // Always narrow UTF-8, regardless of platform.
+ static char embed[EMBED_MAX] = EMBED_HASH_FULL_UTF8;
+
+ static const char hi_part[] = EMBED_HASH_HI_PART_UTF8;
+ static const char lo_part[] = EMBED_HASH_LO_PART_UTF8;
+
+ size_t binding_len = strlen(&embed[0]);
+
+ if (binding_len == 0 || binding_len >= app_dll_len)
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ // Check if the path exceeds the max allowed size
+ if (binding_len > EMBED_MAX - 1)
+ {
+ trace_error(_X("The managed DLL bound to this executable is longer than the max allowed length (%d)"), EMBED_MAX - 1);
+ return false;
+ }
+
+ // Check if the value is the same as the placeholder to detect unbound executables
+ size_t hi_len = sizeof(hi_part) - 1;
+ size_t lo_len = sizeof(lo_part) - 1;
+ if (binding_len >= (hi_len + lo_len)
+ && compare_memory_nooptimization(&embed[0], hi_part, hi_len)
+ && compare_memory_nooptimization(&embed[hi_len], lo_part, lo_len))
+ {
+ trace_error(_X("This executable is not bound to a managed DLL to execute."));
+ return false;
+ }
+
+ if (!pal_utf8_to_palstr(&embed[0], app_dll, app_dll_len))
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ trace_info(_X("The managed DLL bound to this executable is: '%s'"), app_dll);
+ return true;
+}
+
+static void report_outdated_framework_error(const pal_char_t* dotnet_root, const pal_char_t* host_path)
+{
+ pal_char_t download_url[MAX_DOWNLOAD_URL_LEN];
+ utils_get_download_url(download_url, ARRAY_SIZE(download_url), NULL, NULL);
+
+ trace_error(
+ MISSING_RUNTIME_ERROR_FORMAT,
+ INSTALL_OR_UPDATE_NET_ERROR_MESSAGE,
+ host_path,
+ _STRINGIFY(CURRENT_ARCH_NAME),
+ _STRINGIFY(HOST_VERSION),
+ dotnet_root,
+ download_url,
+ _STRINGIFY(HOST_VERSION));
+}
+
+// C equivalent of propagate_error_writer_t
+typedef struct {
+ hostfxr_set_error_writer_fn set_error_writer;
+ bool error_writer_set;
+} propagate_error_writer_state_t;
+
+static void propagate_error_writer_init(propagate_error_writer_state_t* state, hostfxr_set_error_writer_fn set_error_writer)
+{
+ trace_flush();
+
+ state->set_error_writer = set_error_writer;
+ state->error_writer_set = false;
+
+ trace_error_writer_fn error_writer = trace_get_error_writer();
+ if (error_writer != NULL && set_error_writer != NULL)
+ {
+ set_error_writer((hostfxr_error_writer_fn)error_writer);
+ state->error_writer_set = true;
+ }
+}
+
+static void propagate_error_writer_cleanup(propagate_error_writer_state_t* state)
+{
+ if (state->error_writer_set && state->set_error_writer != NULL)
+ {
+ state->set_error_writer(NULL);
+ state->error_writer_set = false;
+ }
+}
+
+static int exe_start(const int argc, const pal_char_t* argv[])
+{
+#if defined(FEATURE_STATIC_HOST)
+ apphost_static_init();
+#endif
+
+ // Use realpath/GetModuleFileName to find the path of the host, resolving any symlinks.
+ pal_char_t* host_path = pal_get_own_executable_path();
+ if (host_path == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), _X("<unknown>"));
+ return CurrentHostFindFailure;
+ }
+
+ pal_char_t* host_path_full = pal_fullpath(host_path, false);
+ if (host_path_full == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), host_path);
+ free(host_path);
+ return CurrentHostFindFailure;
+ }
+
+ free(host_path);
+ host_path = host_path_full;
+
+ bool requires_hostfxr_startupinfo_interface = false;
+
+ // FEATURE_APPHOST path: read embedded DLL name
+ pal_char_t embedded_app_name[EMBED_MAX];
+ if (!is_exe_enabled_for_execution(embedded_app_name, ARRAY_SIZE(embedded_app_name)))
+ {
+ free(host_path);
+ return AppHostExeNotBoundFailure;
+ }
+
+#if defined(_WIN32)
+ for (pal_char_t* c = embedded_app_name; *c != _X('\0'); c++)
+ {
+ if (*c == _X('/'))
+ *c = DIR_SEPARATOR;
+ }
+#endif
+
+ if (pal_strchr(embedded_app_name, DIR_SEPARATOR) != NULL)
+ {
+ requires_hostfxr_startupinfo_interface = true;
+ }
+
+ pal_char_t* app_dir = utils_get_directory(host_path);
+ if (app_dir == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ pal_char_t* app_path = utils_append_path_alloc(app_dir, embedded_app_name);
+ free(app_dir);
+ if (app_path == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ const bool is_bundle = bundle_marker_is_bundle();
+ if (is_bundle)
+ {
+ trace_info(_X("Detected Single-File app bundle"));
+ }
+ else
+ {
+ pal_char_t* app_path_full = pal_fullpath(app_path, false);
+ if (app_path_full == NULL)
+ {
+ trace_error(_X("The application to execute does not exist: '%s'."), app_path);
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ free(app_path);
+ app_path = app_path_full;
+ }
+
+ pal_char_t* app_root = utils_get_directory(app_path);
+ if (app_root == NULL)
+ {
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ hostfxr_resolver_t fxr;
+ hostfxr_resolver_init(&fxr, app_root);
+
+ int rc = fxr.status_code;
+ if (rc != Success)
+ {
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+ }
+
+ if (is_bundle)
+ {
+ hostfxr_main_bundle_startupinfo_fn hostfxr_main_bundle_startupinfo = hostfxr_resolver_resolve_main_bundle_startupinfo(&fxr);
+ if (hostfxr_main_bundle_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+ int64_t bundle_header_offset = bundle_marker_header_offset();
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_bundle_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+ trace_info(_X("Bundle Header Offset: [%" PRId64 "]"), bundle_header_offset);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+ rc = hostfxr_main_bundle_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr, bundle_header_offset);
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not support single-file apps."), fxr.fxr_path);
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ rc = FrameworkMissingFailure;
+ }
+ }
+ else
+ {
+ hostfxr_main_startupinfo_fn hostfxr_main_startupinfo = hostfxr_resolver_resolve_main_startupinfo(&fxr);
+ if (hostfxr_main_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+
+ rc = hostfxr_main_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr);
+
+ if (trace_get_error_writer() != NULL && rc == (int)FrameworkMissingFailure && set_error_writer == NULL)
+ {
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ }
+
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+#if !defined(FEATURE_STATIC_HOST)
+ else
+ {
+ if (requires_hostfxr_startupinfo_interface)
+ {
+ trace_error(_X("The required library %s does not support relative app dll paths."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ else
+ {
+ trace_info(_X("Invoking fx resolver [%s] v1"), fxr.fxr_path);
+
+ // Previous corehost trace messages must be printed before calling trace::setup in hostfxr
+ trace_flush();
+
+ hostfxr_main_fn main_fn_v1 = hostfxr_resolver_resolve_main_v1(&fxr);
+ if (main_fn_v1 != NULL)
+ {
+ rc = main_fn_v1(argc, argv);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not contain the expected entry point."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ }
+ }
+#endif // !defined(FEATURE_STATIC_HOST)
+ }
+
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+}
+
+#if defined(_WIN32)
+int __cdecl wmain(int argc, const pal_char_t* argv[])
+#else
+int main(const int argc, const pal_char_t* argv[])
+#endif
+{
+ trace_setup();
+
+ if (trace_is_enabled())
+ {
+ trace_info(_X("--- Invoked apphost [version: ")
+#if defined(_WIN32)
+ _STRINGIFY(VER_PRODUCTVERSION_STR)
+#else
+ _STRINGIFY(HOST_VERSION) _X(" @Commit: ") _STRINGIFY(REPO_COMMIT_HASH)
+#endif
+ _X("] main = {"));
+ for (int i = 0; i < argc; ++i)
+ {
+ trace_info(_X("%s"), argv[i]);
+ }
+ trace_info(_X("}"));
+ }
+
+#if defined(_WIN32)
+ apphost_buffer_errors();
+#endif
+
+ int exit_code = exe_start(argc, argv);
+
+ trace_flush();
+
+#if defined(_WIN32)
+ apphost_write_buffered_errors(exit_code);
+#endif
+
+ return exit_code;
+}

src/native/corehost/apphost/apphost.c

@@ -0,0 +1,389 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#include "pal.h"
+#include "trace.h"
+#include "utils.h"
+#include "bundle_marker.h"
+#include "apphost_hostfxr_resolver.h"
+#include "error_codes.h"
+#include "hostfxr.h"
+
+#if defined(_WIN32)
+#include "apphost.windows.h"
+#include <_version.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+#if defined(FEATURE_STATIC_HOST)
+extern void apphost_static_init(void);
+#endif
+
+/**
+ * Detect if the apphost executable is allowed to load and execute a managed assembly.
+ *
+ * - The exe is built with a known hash string at some offset in the image
+ * - The exe is useless as is with the built-in hash value, and will fail with an error message
+ * - The hash value should be replaced with the managed DLL filename with optional relative path
+ * - The optional path is relative to the location of the apphost executable
+ * - The relative path plus filename are verified to reference a valid file
+ * - The filename should be "NUL terminated UTF-8" by "dotnet build"
+ * - The managed DLL filename does not have to be the same name as the apphost executable name
+ * - The exe may be signed at this point by the app publisher
+ * - Note: the maximum size of the filename and relative path is 1024 bytes in UTF-8 (not including NUL)
+ * o https://en.wikipedia.org/wiki/Comparison_of_file_systems
+ * has more details on maximum file name sizes.
+ */
+#define EMBED_HASH_HI_PART_UTF8 "c3ab8ff13720e8ad9047dd39466b3c89" // SHA-256 of "foobar" in UTF-8
+#define EMBED_HASH_LO_PART_UTF8 "74e592c2fa383d4a3960714caef0c4f2"
+#define EMBED_HASH_FULL_UTF8 (EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8) // NUL terminated
+
+#define EMBED_SZ (int)(sizeof(EMBED_HASH_FULL_UTF8) / sizeof(EMBED_HASH_FULL_UTF8[0]))
+#define EMBED_MAX (EMBED_SZ > 1025 ? EMBED_SZ : 1025) // 1024 DLL name length, 1 NUL
+
+// This avoids compiler optimization which cause EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8
+// to be placed adjacent causing them to match EMBED_HASH_FULL_UTF8 when searched for replacing.
+// See https://github.com/dotnet/runtime/issues/109611 for more details.
+static bool compare_memory_nooptimization(volatile const char* a, volatile const char* b, size_t length)
+{
+ for (size_t i = 0; i < length; i++)
+ {
+ if (*a++ != *b++)
+ return false;
+ }
+ return true;
+}
+
+// app_dll receives the embedded DLL name as a pal_char_t string.
+// app_dll_len is the buffer size in pal_char_t characters.
+static bool is_exe_enabled_for_execution(pal_char_t* app_dll, size_t app_dll_len)
+{
+ // Contains the EMBED_HASH_FULL_UTF8 value at compile time or the managed DLL name replaced by "dotnet build".
+ // Must not be 'const' because strlen below could be determined at compile time (=64) instead of the actual
+ // length of the string at runtime.
+ // Always narrow UTF-8, regardless of platform.
+ static char embed[EMBED_MAX] = EMBED_HASH_FULL_UTF8;
+
+ static const char hi_part[] = EMBED_HASH_HI_PART_UTF8;
+ static const char lo_part[] = EMBED_HASH_LO_PART_UTF8;
+
+ size_t binding_len = strlen(&embed[0]);
+
+ if (binding_len == 0 || binding_len >= app_dll_len)
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ // Check if the path exceeds the max allowed size
+ if (binding_len > EMBED_MAX - 1)
+ {
+ trace_error(_X("The managed DLL bound to this executable is longer than the max allowed length (%d)"), EMBED_MAX - 1);
+ return false;
+ }
+
+ // Check if the value is the same as the placeholder to detect unbound executables
+ size_t hi_len = sizeof(hi_part) - 1;
+ size_t lo_len = sizeof(lo_part) - 1;
+ if (binding_len >= (hi_len + lo_len)
+ && compare_memory_nooptimization(&embed[0], hi_part, hi_len)
+ && compare_memory_nooptimization(&embed[hi_len], lo_part, lo_len))
+ {
+ trace_error(_X("This executable is not bound to a managed DLL to execute."));
+ return false;
+ }
+
+ if (!pal_utf8_to_palstr(&embed[0], app_dll, app_dll_len))
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ trace_info(_X("The managed DLL bound to this executable is: '%s'"), app_dll);
+ return true;
+}
+
+static void report_outdated_framework_error(const pal_char_t* dotnet_root, const pal_char_t* host_path)
+{
+ pal_char_t download_url[MAX_DOWNLOAD_URL_LEN];
+ utils_get_download_url(download_url, ARRAY_SIZE(download_url), NULL, NULL);
+
+ trace_error(
+ MISSING_RUNTIME_ERROR_FORMAT,
+ INSTALL_OR_UPDATE_NET_ERROR_MESSAGE,
+ host_path,
+ _STRINGIFY(CURRENT_ARCH_NAME),
+ _STRINGIFY(HOST_VERSION),
+ dotnet_root,
+ download_url,
+ _STRINGIFY(HOST_VERSION));
+}
+
+// C equivalent of propagate_error_writer_t
+typedef struct {
+ hostfxr_set_error_writer_fn set_error_writer;
+ bool error_writer_set;
+} propagate_error_writer_state_t;
+
+static void propagate_error_writer_init(propagate_error_writer_state_t* state, hostfxr_set_error_writer_fn set_error_writer)
+{
+ trace_flush();
+
+ state->set_error_writer = set_error_writer;
+ state->error_writer_set = false;
+
+ trace_error_writer_fn error_writer = trace_get_error_writer();
+ if (error_writer != NULL && set_error_writer != NULL)
+ {
+ set_error_writer((hostfxr_error_writer_fn)error_writer);
+ state->error_writer_set = true;
+ }
+}
+
+static void propagate_error_writer_cleanup(propagate_error_writer_state_t* state)
+{
+ if (state->error_writer_set && state->set_error_writer != NULL)
+ {
+ state->set_error_writer(NULL);
+ state->error_writer_set = false;
+ }
+}
+
+static int exe_start(const int argc, const pal_char_t* argv[])
+{
+#if defined(FEATURE_STATIC_HOST)
+ apphost_static_init();
+#endif
+
+ // Use realpath/GetModuleFileName to find the path of the host, resolving any symlinks.
+ pal_char_t* host_path = pal_get_own_executable_path();
+ if (host_path == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), _X("<unknown>"));
+ return CurrentHostFindFailure;
+ }
+
+ pal_char_t* host_path_full = pal_fullpath(host_path, false);
+ if (host_path_full == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), host_path);
+ free(host_path);
+ return CurrentHostFindFailure;
+ }
+
+ free(host_path);
+ host_path = host_path_full;
+
+ bool requires_hostfxr_startupinfo_interface = false;
+
+ // FEATURE_APPHOST path: read embedded DLL name
+ pal_char_t embedded_app_name[EMBED_MAX];
+ if (!is_exe_enabled_for_execution(embedded_app_name, ARRAY_SIZE(embedded_app_name)))
+ {
+ free(host_path);
+ return AppHostExeNotBoundFailure;
+ }
+
+#if defined(_WIN32)
+ for (pal_char_t* c = embedded_app_name; *c != _X('\0'); c++)
+ {
+ if (*c == _X('/'))
+ *c = DIR_SEPARATOR;
+ }
+#endif
+
+ if (pal_strchr(embedded_app_name, DIR_SEPARATOR) != NULL)
+ {
+ requires_hostfxr_startupinfo_interface = true;
+ }
+
+ pal_char_t* app_dir = utils_get_directory(host_path);
+ if (app_dir == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ pal_char_t* app_path = utils_append_path_alloc(app_dir, embedded_app_name);
+ free(app_dir);
+ if (app_path == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ const bool is_bundle = bundle_marker_is_bundle();
+ if (is_bundle)
+ {
+ trace_info(_X("Detected Single-File app bundle"));
+ }
+ else
+ {
+ pal_char_t* app_path_full = pal_fullpath(app_path, false);
+ if (app_path_full == NULL)
+ {
+ trace_error(_X("The application to execute does not exist: '%s'."), app_path);
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ free(app_path);
+ app_path = app_path_full;
+ }
+
+ pal_char_t* app_root = utils_get_directory(app_path);
+ if (app_root == NULL)
+ {
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ hostfxr_resolver_t fxr;
+ hostfxr_resolver_init(&fxr, app_root);
+
+ int rc = fxr.status_code;
+ if (rc != Success)
+ {
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+ }
+
+ if (is_bundle)
+ {
+ hostfxr_main_bundle_startupinfo_fn hostfxr_main_bundle_startupinfo = hostfxr_resolver_resolve_main_bundle_startupinfo(&fxr);
+ if (hostfxr_main_bundle_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+ int64_t bundle_header_offset = bundle_marker_header_offset();
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_bundle_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+ trace_info(_X("Bundle Header Offset: [%" PRId64 "]"), bundle_header_offset);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+ rc = hostfxr_main_bundle_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr, bundle_header_offset);
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not support single-file apps."), fxr.fxr_path);
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ rc = FrameworkMissingFailure;
+ }
+ }
+ else
+ {
+ hostfxr_main_startupinfo_fn hostfxr_main_startupinfo = hostfxr_resolver_resolve_main_startupinfo(&fxr);
+ if (hostfxr_main_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+
+ rc = hostfxr_main_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr);
+
+ if (trace_get_error_writer() != NULL && rc == (int)FrameworkMissingFailure && set_error_writer == NULL)
+ {
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ }
+
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+#if !defined(FEATURE_STATIC_HOST)
+ else
+ {
+ if (requires_hostfxr_startupinfo_interface)
+ {
+ trace_error(_X("The required library %s does not support relative app dll paths."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ else
+ {
+ trace_info(_X("Invoking fx resolver [%s] v1"), fxr.fxr_path);
+
+ // Previous corehost trace messages must be printed before calling trace::setup in hostfxr
+ trace_flush();
+
+ hostfxr_main_fn main_fn_v1 = hostfxr_resolver_resolve_main_v1(&fxr);
+ if (main_fn_v1 != NULL)
+ {
+ rc = main_fn_v1(argc, argv);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not contain the expected entry point."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ }
+ }
+#endif // !defined(FEATURE_STATIC_HOST)
+ }
+
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+}
+
+#if defined(_WIN32)
+int __cdecl wmain(int argc, const pal_char_t* argv[])
+#else
+int main(const int argc, const pal_char_t* argv[])
+#endif
+{
+ trace_setup();
+
+ if (trace_is_enabled())
+ {
+ trace_info(_X("--- Invoked apphost [version: ")
+#if defined(_WIN32)
+ _STRINGIFY(VER_PRODUCTVERSION_STR)
+#else
+ _STRINGIFY(HOST_VERSION) _X(" @Commit: ") _STRINGIFY(REPO_COMMIT_HASH)
+#endif
+ _X("] main = {"));
+ for (int i = 0; i < argc; ++i)
+ {
+ trace_info(_X("%s"), argv[i]);
+ }
+ trace_info(_X("}"));
+ }
+
+#if defined(_WIN32)
+ apphost_buffer_errors();
+#endif
+
+ int exit_code = exe_start(argc, argv);
+
+ trace_flush();
+
+#if defined(_WIN32)
+ apphost_write_buffered_errors(exit_code);
+#endif
+
+ return exit_code;
+}

src/native/corehost/apphost/apphost.c

@@ -0,0 +1,389 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#include "pal.h"
+#include "trace.h"
+#include "utils.h"
+#include "bundle_marker.h"
+#include "apphost_hostfxr_resolver.h"
+#include "error_codes.h"
+#include "hostfxr.h"
+
+#if defined(_WIN32)
+#include "apphost.windows.h"
+#include <_version.h>
+#endif
+
+#include <string.h>
+#include <stdio.h>
+#include <inttypes.h>
+
+#if defined(FEATURE_STATIC_HOST)
+extern void apphost_static_init(void);
+#endif
+
+/**
+ * Detect if the apphost executable is allowed to load and execute a managed assembly.
+ *
+ * - The exe is built with a known hash string at some offset in the image
+ * - The exe is useless as is with the built-in hash value, and will fail with an error message
+ * - The hash value should be replaced with the managed DLL filename with optional relative path
+ * - The optional path is relative to the location of the apphost executable
+ * - The relative path plus filename are verified to reference a valid file
+ * - The filename should be "NUL terminated UTF-8" by "dotnet build"
+ * - The managed DLL filename does not have to be the same name as the apphost executable name
+ * - The exe may be signed at this point by the app publisher
+ * - Note: the maximum size of the filename and relative path is 1024 bytes in UTF-8 (not including NUL)
+ * o https://en.wikipedia.org/wiki/Comparison_of_file_systems
+ * has more details on maximum file name sizes.
+ */
+#define EMBED_HASH_HI_PART_UTF8 "c3ab8ff13720e8ad9047dd39466b3c89" // SHA-256 of "foobar" in UTF-8
+#define EMBED_HASH_LO_PART_UTF8 "74e592c2fa383d4a3960714caef0c4f2"
+#define EMBED_HASH_FULL_UTF8 (EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8) // NUL terminated
+
+#define EMBED_SZ (int)(sizeof(EMBED_HASH_FULL_UTF8) / sizeof(EMBED_HASH_FULL_UTF8[0]))
+#define EMBED_MAX (EMBED_SZ > 1025 ? EMBED_SZ : 1025) // 1024 DLL name length, 1 NUL
+
+// This avoids compiler optimization which cause EMBED_HASH_HI_PART_UTF8 EMBED_HASH_LO_PART_UTF8
+// to be placed adjacent causing them to match EMBED_HASH_FULL_UTF8 when searched for replacing.
+// See https://github.com/dotnet/runtime/issues/109611 for more details.
+static bool compare_memory_nooptimization(volatile const char* a, volatile const char* b, size_t length)
+{
+ for (size_t i = 0; i < length; i++)
+ {
+ if (*a++ != *b++)
+ return false;
+ }
+ return true;
+}
+
+// app_dll receives the embedded DLL name as a pal_char_t string.
+// app_dll_len is the buffer size in pal_char_t characters.
+static bool is_exe_enabled_for_execution(pal_char_t* app_dll, size_t app_dll_len)
+{
+ // Contains the EMBED_HASH_FULL_UTF8 value at compile time or the managed DLL name replaced by "dotnet build".
+ // Must not be 'const' because strlen below could be determined at compile time (=64) instead of the actual
+ // length of the string at runtime.
+ // Always narrow UTF-8, regardless of platform.
+ static char embed[EMBED_MAX] = EMBED_HASH_FULL_UTF8;
+
+ static const char hi_part[] = EMBED_HASH_HI_PART_UTF8;
+ static const char lo_part[] = EMBED_HASH_LO_PART_UTF8;
+
+ size_t binding_len = strlen(&embed[0]);
+
+ if (binding_len == 0 || binding_len >= app_dll_len)
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ // Check if the path exceeds the max allowed size
+ if (binding_len > EMBED_MAX - 1)
+ {
+ trace_error(_X("The managed DLL bound to this executable is longer than the max allowed length (%d)"), EMBED_MAX - 1);
+ return false;
+ }
+
+ // Check if the value is the same as the placeholder to detect unbound executables
+ size_t hi_len = sizeof(hi_part) - 1;
+ size_t lo_len = sizeof(lo_part) - 1;
+ if (binding_len >= (hi_len + lo_len)
+ && compare_memory_nooptimization(&embed[0], hi_part, hi_len)
+ && compare_memory_nooptimization(&embed[hi_len], lo_part, lo_len))
+ {
+ trace_error(_X("This executable is not bound to a managed DLL to execute."));
+ return false;
+ }
+
+ if (!pal_utf8_to_palstr(&embed[0], app_dll, app_dll_len))
+ {
+ trace_error(_X("The managed DLL bound to this executable could not be retrieved from the executable image."));
+ return false;
+ }
+
+ trace_info(_X("The managed DLL bound to this executable is: '%s'"), app_dll);
+ return true;
+}
+
+static void report_outdated_framework_error(const pal_char_t* dotnet_root, const pal_char_t* host_path)
+{
+ pal_char_t download_url[MAX_DOWNLOAD_URL_LEN];
+ utils_get_download_url(download_url, ARRAY_SIZE(download_url), NULL, NULL);
+
+ trace_error(
+ MISSING_RUNTIME_ERROR_FORMAT,
+ INSTALL_OR_UPDATE_NET_ERROR_MESSAGE,
+ host_path,
+ _STRINGIFY(CURRENT_ARCH_NAME),
+ _STRINGIFY(HOST_VERSION),
+ dotnet_root,
+ download_url,
+ _STRINGIFY(HOST_VERSION));
+}
+
+// C equivalent of propagate_error_writer_t
+typedef struct {
+ hostfxr_set_error_writer_fn set_error_writer;
+ bool error_writer_set;
+} propagate_error_writer_state_t;
+
+static void propagate_error_writer_init(propagate_error_writer_state_t* state, hostfxr_set_error_writer_fn set_error_writer)
+{
+ trace_flush();
+
+ state->set_error_writer = set_error_writer;
+ state->error_writer_set = false;
+
+ trace_error_writer_fn error_writer = trace_get_error_writer();
+ if (error_writer != NULL && set_error_writer != NULL)
+ {
+ set_error_writer((hostfxr_error_writer_fn)error_writer);
+ state->error_writer_set = true;
+ }
+}
+
+static void propagate_error_writer_cleanup(propagate_error_writer_state_t* state)
+{
+ if (state->error_writer_set && state->set_error_writer != NULL)
+ {
+ state->set_error_writer(NULL);
+ state->error_writer_set = false;
+ }
+}
+
+static int exe_start(const int argc, const pal_char_t* argv[])
+{
+#if defined(FEATURE_STATIC_HOST)
+ apphost_static_init();
+#endif
+
+ // Use realpath/GetModuleFileName to find the path of the host, resolving any symlinks.
+ pal_char_t* host_path = pal_get_own_executable_path();
+ if (host_path == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), _X("<unknown>"));
+ return CurrentHostFindFailure;
+ }
+
+ pal_char_t* host_path_full = pal_fullpath(host_path, false);
+ if (host_path_full == NULL)
+ {
+ trace_error(_X("Failed to resolve full path of the current executable [%s]"), host_path);
+ free(host_path);
+ return CurrentHostFindFailure;
+ }
+
+ free(host_path);
+ host_path = host_path_full;
+
+ bool requires_hostfxr_startupinfo_interface = false;
+
+ // FEATURE_APPHOST path: read embedded DLL name
+ pal_char_t embedded_app_name[EMBED_MAX];
+ if (!is_exe_enabled_for_execution(embedded_app_name, ARRAY_SIZE(embedded_app_name)))
+ {
+ free(host_path);
+ return AppHostExeNotBoundFailure;
+ }
+
+#if defined(_WIN32)
+ for (pal_char_t* c = embedded_app_name; *c != _X('\0'); c++)
+ {
+ if (*c == _X('/'))
+ *c = DIR_SEPARATOR;
+ }
+#endif
+
+ if (pal_strchr(embedded_app_name, DIR_SEPARATOR) != NULL)
+ {
+ requires_hostfxr_startupinfo_interface = true;
+ }
+
+ pal_char_t* app_dir = utils_get_directory(host_path);
+ if (app_dir == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ pal_char_t* app_path = utils_append_path_alloc(app_dir, embedded_app_name);
+ free(app_dir);
+ if (app_path == NULL)
+ {
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ const bool is_bundle = bundle_marker_is_bundle();
+ if (is_bundle)
+ {
+ trace_info(_X("Detected Single-File app bundle"));
+ }
+ else
+ {
+ pal_char_t* app_path_full = pal_fullpath(app_path, false);
+ if (app_path_full == NULL)
+ {
+ trace_error(_X("The application to execute does not exist: '%s'."), app_path);
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ free(app_path);
+ app_path = app_path_full;
+ }
+
+ pal_char_t* app_root = utils_get_directory(app_path);
+ if (app_root == NULL)
+ {
+ free(app_path);
+ free(host_path);
+ return AppPathFindFailure;
+ }
+
+ hostfxr_resolver_t fxr;
+ hostfxr_resolver_init(&fxr, app_root);
+
+ int rc = fxr.status_code;
+ if (rc != Success)
+ {
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+ }
+
+ if (is_bundle)
+ {
+ hostfxr_main_bundle_startupinfo_fn hostfxr_main_bundle_startupinfo = hostfxr_resolver_resolve_main_bundle_startupinfo(&fxr);
+ if (hostfxr_main_bundle_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+ int64_t bundle_header_offset = bundle_marker_header_offset();
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_bundle_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+ trace_info(_X("Bundle Header Offset: [%" PRId64 "]"), bundle_header_offset);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+ rc = hostfxr_main_bundle_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr, bundle_header_offset);
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not support single-file apps."), fxr.fxr_path);
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ rc = FrameworkMissingFailure;
+ }
+ }
+ else
+ {
+ hostfxr_main_startupinfo_fn hostfxr_main_startupinfo = hostfxr_resolver_resolve_main_startupinfo(&fxr);
+ if (hostfxr_main_startupinfo != NULL)
+ {
+ const pal_char_t* host_path_cstr = host_path;
+ const pal_char_t* dotnet_root_cstr = fxr.dotnet_root != NULL && fxr.dotnet_root[0] != _X('\0') ? fxr.dotnet_root : NULL;
+ const pal_char_t* app_path_cstr = app_path[0] != _X('\0') ? app_path : NULL;
+
+ trace_info(_X("Invoking fx resolver [%s] hostfxr_main_startupinfo"), fxr.fxr_path);
+ trace_info(_X("Host path: [%s]"), host_path);
+ trace_info(_X("Dotnet path: [%s]"), fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""));
+ trace_info(_X("App path: [%s]"), app_path);
+
+ hostfxr_set_error_writer_fn set_error_writer = hostfxr_resolver_resolve_set_error_writer(&fxr);
+ propagate_error_writer_state_t propagate_state;
+ propagate_error_writer_init(&propagate_state, set_error_writer);
+
+ rc = hostfxr_main_startupinfo(argc, argv, host_path_cstr, dotnet_root_cstr, app_path_cstr);
+
+ if (trace_get_error_writer() != NULL && rc == (int)FrameworkMissingFailure && set_error_writer == NULL)
+ {
+ report_outdated_framework_error(fxr.dotnet_root != NULL ? fxr.dotnet_root : _X(""), host_path);
+ }
+
+ propagate_error_writer_cleanup(&propagate_state);
+ }
+#if !defined(FEATURE_STATIC_HOST)
+ else
+ {
+ if (requires_hostfxr_startupinfo_interface)
+ {
+ trace_error(_X("The required library %s does not support relative app dll paths."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ else
+ {
+ trace_info(_X("Invoking fx resolver [%s] v1"), fxr.fxr_path);
+
+ // Previous corehost trace messages must be printed before calling trace::setup in hostfxr
+ trace_flush();
+
+ hostfxr_main_fn main_fn_v1 = hostfxr_resolver_resolve_main_v1(&fxr);
+ if (main_fn_v1 != NULL)
+ {
+ rc = main_fn_v1(argc, argv);
+ }
+ else
+ {
+ trace_error(_X("The required library %s does not contain the expected entry point."), fxr.fxr_path);
+ rc = CoreHostEntryPointFailure;
+ }
+ }
+ }
+#endif // !defined(FEATURE_STATIC_HOST)
+ }
+
+ hostfxr_resolver_cleanup(&fxr);
+ free(app_root);
+ free(app_path);
+ free(host_path);
+ return rc;
+}
+
+#if defined(_WIN32)
+int __cdecl wmain(int argc, const pal_char_t* argv[])
+#else
+int main(const int argc, const pal_char_t* argv[])
+#endif
+{
+ trace_setup();
+
+ if (trace_is_enabled())
+ {
+ trace_info(_X("--- Invoked apphost [version: ")
+#if defined(_WIN32)
+ _STRINGIFY(VER_PRODUCTVERSION_STR)
+#else
+ _STRINGIFY(HOST_VERSION) _X(" @Commit: ") _STRINGIFY(REPO_COMMIT_HASH)
+#endif
+ _X("] main = {"));
+ for (int i = 0; i < argc; ++i)
+ {
+ trace_info(_X("%s"), argv[i]);
+ }
+ trace_info(_X("}"));
+ }
+
+#if defined(_WIN32)
+ apphost_buffer_errors();
+#endif
+
+ int exit_code = exe_start(argc, argv);
+
+ trace_flush();
+
+#if defined(_WIN32)
+ apphost_write_buffered_errors(exit_code);
+#endif
+
+ return exit_code;
+}