Fix exit-status: send SSH_MSG_CHANNEL_REQUEST exit-status per RFC 4254 §6.10

AGENTS.md

@@ -2850,5 +2850,38 @@ chacha20-poly1305@openssh.com
 
 ---
 
-**最后更新**：2026-06-20 13:45
-**版本**：1.30（Phase 8.3 Docker 测试完成）
+---
+
+## exit-status 修复完成（2026-06-20）⭐⭐⭐⭐⭐
+
+**背景**：SSH `ssh -p 2024 demo@127.0.0.1 "echo hello"` 返回 `exit status -1`
+
+**根本原因**（RFC 4254 §6.10）：
+- OpenSSH client 要求 server 在通道关闭前发送 `SSH_MSG_CHANNEL_REQUEST "exit-status"`
+- `handle_child_exited()` 之前只发送 EOF + CLOSE，从未发送 `exit-status` 请求
+- 因此 OpenSSH client 不知道子进程的退出码，报告 `exit status -1`
+
+**修复内容**（`channel.rs`）：
+
+| 修改 | 位置 | 说明 |
+|------|------|------|
+| `exit_status: Option<u32>` | `Channel` struct | 存储子进程退出码 |
+| `channel.exit_status = Some(exit_code)` | `poll_exec_stdout_and_client()` | 在 `child.try_wait()` 返回 status 时保存退出码 |
+| `build_channel_exit_status()` | 新函数 | 构建 `SSH_MSG_CHANNEL_REQUEST "exit-status" FALSE <code>` |
+| 发送 exit-status → EOF → CLOSE | `handle_child_exited()` | 按正确顺序发送三个消息 |
+
+**验证结果**：
+```bash
+$ ssh -p 2024 demo@127.0.0.1 "echo hello"
+hello                         # ✅ exit status 0 (默认)
+
+$ ssh -p 2024 demo@127.0.0.1 "exit 42"
+                              # 无输出（exit 42 不产生 stdout）
+$ echo $?
+42                            # ✅ exit status 42 正确传递
+```
+
+**累计代码**：5061 行（新增 31 行）
+
+**最后更新**：2026-06-20 14:15
+**版本**：1.31（exit-status 修复完成）

markbase-core/src/ssh_server/channel.rs

@@ -176,6 +176,7 @@ impl ChannelManager {
             scp_handler: None,
             rsync_handler: None,
             exec_process: None,            // Phase 14: 交互式exec
+            exit_status: None,             // ⭐⭐⭐⭐⭐ exit status from child process
             sftp_input_buffer: Vec::new(), // ⭐⭐⭐⭐⭐ Phase 14.2修复：SFTP packet累积
             scp_input_buffer: Vec::new(),  // ⭐⭐⭐⭐⭐ Phase 14.4修复：SCP packet累积
             scp_state: ScpState::Idle,       // ⭐⭐⭐⭐⭐ Phase 8.3: SCP state machine
@@ -254,6 +255,7 @@ impl ChannelManager {
             scp_handler: None,
             rsync_handler: None,
             exec_process: None,
+            exit_status: None,             // ⭐⭐⭐⭐⭐ exit status from child process
             sftp_input_buffer: Vec::new(),
             scp_input_buffer: Vec::new(),
             scp_state: ScpState::Idle,       // ⭐⭐⭐⭐⭐ Phase 8.3: SCP state machine
@@ -329,6 +331,7 @@ impl ChannelManager {
             scp_handler: None,
             rsync_handler: None,
             exec_process: None,            // Phase 14: 交互式exec
+            exit_status: None,             // ⭐⭐⭐⭐⭐ exit status from child process
             sftp_input_buffer: Vec::new(), // ⭐⭐⭐⭐⭐ Phase 14.2修复
             scp_input_buffer: Vec::new(),  // ⭐⭐⭐⭐⭐ Phase 14.4修复
             scp_state: ScpState::Idle,       // ⭐⭐⭐⭐⭐ Phase 8.3: SCP state machine
@@ -1303,6 +1306,19 @@ impl ChannelManager {
     /// ⭐⭐⭐⭐⭐ 关键：非阻塞读取数据，不等待子进程完成
     /// ⭐⭐⭐⭐⭐ Phase 14.2: 处理child exited（发送EOF + CLOSE）
     /// 参考：OpenSSH session.c: do_exec_no_pty()
+    /// Build SSH_MSG_CHANNEL_REQUEST "exit-status" (RFC 4254 §6.10)
+    pub fn build_channel_exit_status(&self, channel: u32, exit_code: u32) -> Result<SshPacket> {
+        let mut payload = Vec::new();
+        payload.write_u8(PacketType::SSH_MSG_CHANNEL_REQUEST as u8)?;
+        payload.write_u32::<BigEndian>(channel)?;
+        let name = "exit-status";
+        payload.write_u32::<BigEndian>(name.len() as u32)?;
+        payload.write_all(name.as_bytes())?;
+        payload.write_u8(0)?; // FALSE (want_reply)
+        payload.write_u32::<BigEndian>(exit_code)?;
+        Ok(SshPacket::new(payload))
+    }
+
     pub fn handle_child_exited(&mut self) -> Result<Vec<SshPacket>> {
         // 1. 收集需要处理的channel IDs (exec_process OR rsync_handler)
         let channel_ids: Vec<u32> = self
@@ -1320,6 +1336,14 @@ impl ChannelManager {
         // 2. 构建packets（避免borrow冲突）
         let mut packets = Vec::new();
         for channel_id in &channel_ids {
+            // Send exit-status first (RFC 4254 §6.10)
+            let exit_code = self.channels.get(channel_id)
+                .and_then(|c| c.exit_status)
+                .unwrap_or(255);
+            let exit_packet = self.build_channel_exit_status(*channel_id, exit_code)?;
+            packets.push(exit_packet);
+
+            // Then EOF + CLOSE
             let eof_packet = self.build_channel_eof(*channel_id)?;
             packets.push(eof_packet);
 
@@ -1332,12 +1356,13 @@ impl ChannelManager {
             if let Some(channel) = self.channels.get_mut(channel_id) {
                 channel.exec_process = None;
                 channel.rsync_handler = None;
+                channel.exit_status = None;
             }
         }
 
         if !channel_ids.is_empty() {
             info!(
-                "Child/rsync exited, sent EOF + CLOSE for {} channels",
+                "Child/rsync exited, sent exit-status + EOF + CLOSE for {} channels",
                 channel_ids.len()
             );
         }
@@ -1498,11 +1523,13 @@ impl ChannelManager {
                                 if let Some(exec_process) = &mut channel.exec_process {
                                     match exec_process.child.try_wait() {
                                         Ok(Some(status)) => {
+                                            let exit_code = status.code().unwrap_or(-1) as u32;
                                             info!(
-                                                "Child process exited (channel {}, status: {:?})",
-                                                channel_id, status
+                                                "Child process exited (channel {}, exit_status: {}, status: {:?})",
+                                                channel_id, exit_code, status
                                             );
                                             child_exited = true;
+                                            channel.exit_status = Some(exit_code);
 
                                             let command_str = exec_process.command.clone();
                                             let should_trigger_hook = status.success() 
@@ -2005,6 +2032,7 @@ struct Channel {
     scp_handler: Option<ScpHandler>,     // Phase 8: SCP处理器
     rsync_handler: Option<RsyncHandler>, // Phase 8: rsync处理器
     exec_process: Option<ExecProcess>,   // Phase 14: 交互式exec进程
+    exit_status: Option<u32>,            // ⭐⭐⭐⭐⭐ exit status from child process
     // ⭐⭐⭐⭐⭐ Critical修复：SFTP packet累积buffer
     sftp_input_buffer: Vec<u8>, // Phase 14.2修复：累积不完整的SFTP packets
     // ⭐⭐⭐⭐⭐ Phase 14.4：SCP packet累积buffer