Avoid race condition.

So far, both the A2 and ioctl(..., TIOCSTI, ...) could be writing to the serial input queue.

Now, we wait one millisec for the A2 to complete its initial writing. Then we read the complete input from the queue and push back all chars other than Reset.

src/a2pid.c

@@ -703,14 +703,21 @@ openserial:
         }
     }
     /* drain superfluous sync requests from potential fifo */
-    while (read(a2fd, iopkt, 1) == 1)
+    usleep(1000);
+    c = read(a2fd, iopkt, sizeof(iopkt));
+    for (i = 0; i < c; i++)
     {
+#ifdef TRACE
+        printf("a2pid: drain 0x%02X\n", iopkt[i]);
+#endif
         /* there's already some other request */
-        if (iopkt[0] != 0x80)
+        if (iopkt[i] != 0x80)
         {
+#ifdef TRACE
+            printf("a2pid: push back 0x%02X\n", iopkt[i]);
+#endif
             /* 'simulate terminal input' for a push back */
-            ioctl(a2fd, TIOCSTI, iopkt);
-            break;
+            ioctl(a2fd, TIOCSTI, &iopkt[i]);
         }
     }
     newtio.c_cc[VMIN] = 3; /* blocking read until 3 chars received */