修复就绪屏障位被消费致FTP永不监听；新增栈可观测（水位探针+静态调用图报告）并补FTP实测

test/ftp_up_dl_test.py

@@ -48,6 +48,34 @@ def send_cmd(sock, cmd, expect_code=None):
     print("  < [NO RESPONSE]")
     return None
 
+def connect_with_retry(host, port, timeout=TIMEOUT, attempts=6, delay=3.0):
+    """连接控制通道（带重试）。
+
+    CH395F 是单客户端复用：上一会话未 QUIT 就断开时，服务端仍在处理旧连接，
+    新连接会被 RST（WinError 10061）。实测旧会话约 30s 后被服务端丢弃并重新
+    listen，故这里等一会儿重试即可，不要用裸 TCP 探测端口（探测本身会占掉
+    唯一会话）。
+    """
+    last_err = None
+    for i in range(1, attempts + 1):
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        s.settimeout(timeout)
+        try:
+            s.connect((host, port))
+            return s, None
+        except Exception as e:
+            last_err = e
+            try:
+                s.close()
+            except Exception:
+                pass
+            if i < attempts:
+                print(f"    connect failed ({e}); retry {i}/{attempts - 1} in {delay:.0f}s "
+                      f"(single-client: stale session blocks new connections)")
+                time.sleep(delay)
+    return None, last_err
+
+
 def parse_pasv(resp):
     m = re.search(r"(\d+),(\d+),(\d+),(\d+),(\d+),(\d+)", resp.decode())
     if m:
@@ -55,77 +83,6 @@ def parse_pasv(resp):
         return f"{a}.{b}.{c}.{d}", e * 256 + f
     return None, None
 
-def ftp_transfer_data(host, pasv_ip, pasv_port, cmd, data_to_send=None, read_data=False):
-    """通用数据通道传输：发送命令 + 连数据端口 + 收发数据"""
-    print(f"\n  [{cmd}] Opening data channel {pasv_ip}:{pasv_port}...")
-    data_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    data_sock.settimeout(10.0)
-    try:
-        data_sock.connect((pasv_ip, pasv_port))
-        print(f"  Data channel connected.")
-
-        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        sock.settimeout(TIMEOUT)
-        sock.connect((host, PORT))
-        recv_line(sock)  # 220
-        send_cmd(sock, "USER anonymous")
-        send_cmd(sock, "PASS test@test.com")
-
-        # PASV
-        resp = send_cmd(sock, "PASV")
-        _, data_port = parse_pasv(resp)
-        print(f"  PASV port: {data_port}")
-
-        # Connect data FIRST
-        data_sock2 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        data_sock2.settimeout(10.0)
-        data_sock2.connect((pasv_ip, data_port))
-
-        # Send command
-        time.sleep(0.2)
-        send_cmd(sock, cmd)
-
-        result = None
-        if data_to_send:
-            print(f"  Sending {len(data_to_send)} bytes to data channel...")
-            total = 0
-            while total < len(data_to_send):
-                n = data_sock2.send(data_to_send[total:])
-                if n <= 0:
-                    break
-                total += n
-            print(f"  Sent {total} bytes.")
-            data_sock2.shutdown(socket.SHUT_WR)
-
-        if read_data:
-            result = b""
-            while True:
-                try:
-                    chunk = data_sock2.recv(4096)
-                    if not chunk:
-                        break
-                    result += chunk
-                except socket.timeout:
-                    break
-            print(f"  Received {len(result)} bytes from data channel.")
-
-        data_sock2.close()
-        resp = recv_line(sock)
-        if resp:
-            print(f"  Control response: {resp.decode().rstrip()}")
-
-        send_cmd(sock, "QUIT")
-        sock.close()
-        data_sock.close()
-        return result
-    except Exception as e:
-        print(f"  Data transfer error: {e}")
-        try:
-            data_sock.close()
-        except:
-            pass
-        return None
-
 def test_upload_download(host, port):
     print(f"=== FTP Upload/Download Test: {host}:{port} ===\n")
     checks = []
@@ -156,14 +113,11 @@ def test_upload_download(host, port):
 
     # 1. Connect + Login
     print("[1] Connect + Login")
-    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    sock.settimeout(TIMEOUT)
-    try:
-        sock.connect((host, port))
-    except Exception as e:
-        print(f"    CONNECT FAILED: {e}")
-        check("Connect", False, str(e))
-        return finish(sock)
+    sock, err = connect_with_retry(host, port)
+    if sock is None:
+        print(f"    CONNECT FAILED: {err}")
+        check("Connect", False, str(err))
+        return finish(None)
     recv_line(sock)  # 220
 
     if not send_cmd(sock, "USER anonymous", 230):