W19: plugin_loader hardening — ABI try/catch, path validation, atomic IDs, CLI exit codes (W19.1-W19.5)

Fixes: F-18.3-1 through F-18.3-5 (all CLOSED, findings registry at zero)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

dstalk-cli/src/main.cpp

@@ -35,10 +35,11 @@
 #define CLR_BOLD    "\033[1m"
 
 // ---- 退出码 ----
+// 0=正常退出  1=用户中断(SIGINT/Ctrl+C)  2=致命错误  3=配置错误
 #define EXIT_OK            0
-#define EXIT_INIT_FAIL     1
-#define EXIT_AI_ERROR      2
-#define EXIT_SVC_UNAVAIL   3
+#define EXIT_INTERRUPT     1
+#define EXIT_FATAL         2
+#define EXIT_CONFIG        3
 
 // ---- 服务 vtable 指针 ----
 static const dstalk_ai_service_t*      g_ai      = nullptr;
@@ -48,12 +49,14 @@ static const dstalk_file_io_service_t* g_file_io = nullptr;
 // ---- 运行时状态 ----
 static std::string       g_current_model;
 static std::atomic<bool> g_quit_requested{false};
+static std::atomic<bool> g_quit_via_signal{false};
 
 // ---- Ctrl+C 信号处理 ----
 #ifdef _WIN32
 static BOOL WINAPI on_console_event(DWORD event)
 {
     if (event == CTRL_C_EVENT || event == CTRL_BREAK_EVENT) {
+        g_quit_via_signal = true;
         g_quit_requested = true;
         return TRUE;
     }
@@ -62,6 +65,7 @@ static BOOL WINAPI on_console_event(DWORD event)
 #else
 static void on_signal(int /*sig*/)
 {
+    g_quit_via_signal = true;
     g_quit_requested = true;
 }
 #endif
@@ -154,7 +158,6 @@ static void handle_command(const char* line)
     // /quit  —— 设置退出标志，让控制流自然回到 main 末尾
     if (std::strcmp(line, "/quit") == 0 || std::strcmp(line, "/q") == 0) {
         g_quit_requested = true;
-        std::printf("再见!\n");
         return;
     }
 
@@ -442,7 +445,7 @@ int main(int argc, char* argv[])
     // 初始化主机（加载配置 + 自动扫描 plugins/ 目录加载插件）
     if (dstalk_init(config_path) != 0) {
         std::fprintf(stderr, CLR_RED "[dstalk] 初始化失败\n" CLR_RESET);
-        return EXIT_INIT_FAIL;
+        return EXIT_CONFIG;
     }
 
     // 查询插件服务
@@ -486,12 +489,12 @@ int main(int argc, char* argv[])
         if (input.empty()) {
             std::fprintf(stderr, "empty prompt\n");
             dstalk_shutdown();
-            return 1;
+            return EXIT_FATAL;
         }
         if (!g_ai || !g_session) {
             std::fprintf(stderr, CLR_RED "[ERROR] AI or session service unavailable\n" CLR_RESET);
             dstalk_shutdown();
-            return EXIT_SVC_UNAVAIL;
+            return EXIT_CONFIG;
         }
         int history_count = 0;
         const dstalk_message_t* history = g_session->history(&history_count);
@@ -506,14 +509,17 @@ int main(int argc, char* argv[])
                         result.error ? result.error : "unknown");
             g_ai->free_result(&result);
             dstalk_shutdown();
-            return EXIT_AI_ERROR;
+            return EXIT_FATAL;
         }
     }
 
     char buffer[8192];
     while (true) {
         // B1: 检查退出标志
-        if (g_quit_requested) break;
+        if (g_quit_requested) {
+            std::printf("再见!\n");
+            break;
+        }
 
         // A1: 提示符带模型名（batch 模式不打印）
         if (!batch_mode) {
@@ -574,7 +580,7 @@ int main(int argc, char* argv[])
         g_ai->free_result(&result);
     }
 
-    // B2: 单一退出点，dstalk_shutdown 只在此调用
+    // B2: 单一退出点，dstalk_shutdown 只在此调用（交互模式下）
     dstalk_shutdown();
-    return EXIT_OK;
+    return g_quit_via_signal ? EXIT_INTERRUPT : EXIT_OK;
 }