Fix for https://github.com/dart-lang/sdk/issues/61206

Ensure Platform.executable is not resolved.

TEST=new test case added

Bug: 61206
Change-Id: I0522869f57d519168542b453dc2e827d9d5e6486
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/442942
Commit-Queue: Siva Annamalai <asiva@google.com>
Reviewed-by: Nicholas Shahan <nshahan@google.com>

runtime/bin/dartdev.cc

@@ -502,7 +502,7 @@ class DartDev {
     int idx = 0;
     char err_msg[256];
     err_msg[0] = '\0';
-    intptr_t num_args = argc + 2;
+    intptr_t num_args = argc + 3;
     char** exec_argv = new char*[num_args];
 #if defined(DART_HOST_OS_WINDOWS)
     char* exec_name = StringUtilsWin::ArgumentEscape(dartvm_path.get());
@@ -515,11 +515,20 @@ class DartDev {
     Platform::ResolveExecutablePathInto(dart_path, kPathBufSize);
     idx += 1;
 #if defined(DART_HOST_OS_WINDOWS)
-    char* dart_name = Utils::SCreate("--executable_name=%s", dart_path);
+    char* dart_name =
+        Utils::SCreate("--resolved_executable_name=%s", dart_path);
+    exec_argv[idx] = StringUtilsWin::ArgumentEscape(dart_name);
+    free(dart_name);
+    idx += 1;
+    dart_name =
+        Utils::SCreate("--executable_name=%s", Platform::GetExecutableName());
     exec_argv[idx] = StringUtilsWin::ArgumentEscape(dart_name);
     free(dart_name);
 #else
-    exec_argv[idx] = Utils::SCreate("--executable_name=%s", dart_path);
+    exec_argv[idx] = Utils::SCreate("--resolved_executable_name=%s", dart_path);
+    idx += 1;
+    exec_argv[idx] =
+        Utils::SCreate("--executable_name=%s", Platform::GetExecutableName());
 #endif
     for (intptr_t i = 1; i < argc; ++i) {
 #if defined(DART_HOST_OS_WINDOWS)
@@ -629,9 +638,9 @@ class DartDev {
     };
     // Total count of arguments to be passed to the script being execed.
     if (mark_main_isolate_as_system_isolate) {
-      argc_ = argc + num_vm_options + 4;
+      argc_ = argc + num_vm_options + 5;
     } else {
-      argc_ = argc + num_vm_options + 3;
+      argc_ = argc + num_vm_options + 4;
     }
 
     // Array of arguments to be passed to the script being execed.
@@ -657,11 +666,18 @@ class DartDev {
       char dart_path[kPathBufSize];
       Platform::ResolveExecutablePathInto(dart_path, kPathBufSize);
 #if defined(DART_HOST_OS_WINDOWS)
-      char* dart_name = Utils::SCreate("--executable_name=%s", dart_path);
+      char* dart_name =
+          Utils::SCreate("--resolved_executable_name=%s", dart_path);
+      argv_[idx++] = StringUtilsWin::ArgumentEscape(dart_name);
+      free(dart_name);
+      dart_name =
+          Utils::SCreate("--executable_name=%s", Platform::GetExecutableName());
       argv_[idx++] = StringUtilsWin::ArgumentEscape(dart_name);
       free(dart_name);
 #else
-      argv_[idx++] = Utils::SCreate("--executable_name=%s", dart_path);
+      argv_[idx++] = Utils::SCreate("--resolved_executable_name=%s", dart_path);
+      argv_[idx++] =
+          Utils::SCreate("--executable_name=%s", Platform::GetExecutableName());
 #endif
     }
     if (mark_main_isolate_as_system_isolate) {

runtime/bin/dartdev_options.cc

@@ -148,6 +148,9 @@ bool Options::ParseDartDevArguments(int argc,
                                     CommandLineOptions* dart_vm_options,
                                     CommandLineOptions* dart_options,
                                     bool* skip_dartdev) {
+  // Store the executable name.
+  Platform::SetExecutableName(argv[0]);
+
   // First figure out if a dartdev command has been explicitly specified.
   *skip_dartdev = false;
   int tmp_i = 1;
@@ -317,9 +320,6 @@ bool Options::ParseDartDevArguments(int argc,
     i++;
   }
 
-  // Store the executable name.
-  Platform::SetExecutableName(argv[0]);
-
   // Verify consistency of arguments.
   if ((packages_file_ != nullptr) && (strlen(packages_file_) == 0)) {
     Syslog::PrintErr("Empty package file name specified.\n");

runtime/bin/main_options.cc

@@ -226,10 +226,12 @@ bool Options::ParseArguments(int argc,
     // Store the executable name.
     if (Options::executable_name() != nullptr) {
       Platform::SetExecutableName(Options::executable_name());
-      Platform::SetResolvedExecutableName(Options::executable_name());
     } else {
       Platform::SetExecutableName(argv[0]);
     }
+    if (Options::resolved_executable_name() != nullptr) {
+      Platform::SetResolvedExecutableName(Options::resolved_executable_name());
+    }
   }
 
   // Verify consistency of arguments.

runtime/bin/main_options.h

@@ -29,6 +29,7 @@ namespace bin {
   V(namespace, namespc)                                                        \
   V(write_service_info, vm_write_service_info_filename)                        \
   V(executable_name, executable_name)                                          \
+  V(resolved_executable_name, resolved_executable_name)                        \
   /* The purpose of these flags is documented in */                            \
   /* pkg/dartdev/lib/src/commands/compilation_server.dart. */                  \
   V(resident_server_info_file, resident_server_info_file_path)                 \

runtime/bin/platform_macos.cc

@@ -255,18 +255,36 @@ const char* Platform::ResolveExecutablePath() {
 }
 
 intptr_t Platform::ResolveExecutablePathInto(char* result, size_t result_size) {
-  // Get the required length of the buffer.
-  uint32_t path_size = 0;
-  if (_NSGetExecutablePath(nullptr, &path_size) == 0) {
+  // A temporary buffer to hold the initial executable path.
+  char exe_path[PATH_MAX + 1];
+  uint32_t exe_path_size = sizeof(exe_path);
+
+  // Get the path of the executable.
+  if (_NSGetExecutablePath(exe_path, &exe_path_size) != 0) {
+    // The buffer was too small. Get the required size and handle the error.
+    // For this specific use case, we assume PATH_MAX is sufficient.
     return -1;
   }
-  if (path_size > result_size) {
+
+  // Now, canonicalize the path to resolve symlinks.
+  // realpath is the standard POSIX function for this purpose.
+  char resolved_exe_path[PATH_MAX + 1];
+  if (realpath(exe_path, resolved_exe_path) == nullptr) {
     return -1;
   }
-  if (_NSGetExecutablePath(result, &path_size) != 0) {
+
+  // Check if the resolved path fits into the destination buffer.
+  size_t resolved_size = strlen(resolved_exe_path);
+  if (resolved_size >= result_size) {
+    // The buffer is too small.
     return -1;
   }
-  return path_size;
+
+  // Safely copy the resolved path.
+  strncpy(result, resolved_exe_path, resolved_size);
+  result[resolved_size] = '\0';
+
+  return resolved_size;
 }
 
 void Platform::SetProcessName(const char* name) {

tests/standalone/io/platform_executable_test.dart

@@ -0,0 +1,81 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// This test was generated by Gemini.
+
+import 'dart:io';
+import 'package:test/test.dart';
+
+// The simple script to be run in a child process.
+// It prints both executable paths to standard output.
+const String _testScriptContent = '''
+import 'dart:io';
+
+void main() {
+  print(Platform.executable);
+  print(Platform.resolvedExecutable);
+}
+''';
+
+void main() {
+  group('Platform executable properties', () {
+    test(
+      'Platform.executable and Platform.resolvedExecutable should differ '
+      'when executed via a symbolic link',
+      () {
+        // 1. Get the absolute path to the current Dart executable.
+        final dartExecutablePath = Platform.resolvedExecutable;
+
+        // 2. Create a temporary directory and the necessary files.
+        final tempDir = Directory.systemTemp.createTempSync(
+          'dart_symlink_test_',
+        );
+        final symlinkPath =
+            '${tempDir.path}${Platform.pathSeparator}dart_symlink';
+        final childScriptPath =
+            '${tempDir.path}${Platform.pathSeparator}child_script.dart';
+
+        try {
+          // Create the symbolic link.
+          Link(symlinkPath).createSync(dartExecutablePath, recursive: true);
+
+          // Write the child script to a file.
+          File(childScriptPath).writeAsStringSync(_testScriptContent);
+
+          // 3. Execute the child script using the symlink.
+          final result = Process.runSync(
+            symlinkPath, // This is the key: use the symlink path
+            [childScriptPath],
+            runInShell: true,
+          );
+
+          // Verify the child process exited successfully.
+          expect(
+            result.exitCode,
+            0,
+            reason: 'Child process failed: ${result.stderr}',
+          );
+
+          // 4. Parse the output.
+          final output = result.stdout.toString().trim().split('\n');
+          final executablePath = output[0];
+          final resolvedExecutablePath = output[1];
+
+          // 5. Assert the paths are different.
+          expect(executablePath, isNot(equals(resolvedExecutablePath)));
+          print('Executable: $executablePath');
+          print('Resolved Executable: $resolvedExecutablePath');
+        } finally {
+          // Clean up the temporary directory.
+          if (tempDir.existsSync()) {
+            tempDir.deleteSync(recursive: true);
+          }
+        }
+      },
+      // This is the important part: use the 'skip' parameter.
+      // The test will be skipped unless the platform is Linux or MacOS.
+      skip: (!Platform.isLinux && !Platform.isMacOS) ? true : false,
+    );
+  });
+}

tests/standalone/standalone_kernel.status

@@ -49,6 +49,7 @@ io/http_response_deadline_test: Skip # Flaky.
 io/http_reuse_server_port_test: Skip # Flaky.
 io/http_server_close_response_after_error_test: Skip # Flaky.
 io/http_shutdown_test: Skip # Flaky.
+io/platform_executable_test: Skip # The test assumes a JIT invocation.
 io/process_child_test: Skip # The test does not exercise the exec path on AOT
 io/raw_datagram_socket_test: Skip # Flaky.
 io/raw_secure_server_closing_test: Skip # Flaky