Cygwin: pty: Avoid screen distortion on slave read.

- Echo back print is distorted when the cygwin program which calls
  Win32 console API directly calls slave read(). This patch fixes
  the issue.

diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h
index 53b6c2c45d334114522363df9d88ea82151fd003..a22f3a1365a9554845b3a800d23324600b7fc37a 100644 (file)
--- a/winsup/cygwin/fhandler.h
+++ b/winsup/cygwin/fhandler.h
@@ -2206,7 +2206,7 @@ class fhandler_pty_slave: public fhandler_pty_common
   }
   void set_switch_to_pcon (int fd);
   void reset_switch_to_pcon (void);
-  void push_to_pcon_screenbuffer (const char *ptr, size_t len);
+  void push_to_pcon_screenbuffer (const char *ptr, size_t len, bool is_echo);
   void mask_switch_to_pcon_in (bool mask);
   void fixup_after_attach (bool native_maybe, int fd);
   bool is_line_input (void)
@@ -2215,6 +2215,7 @@ class fhandler_pty_slave: public fhandler_pty_common
   }
   void setup_locale (void);
   void set_freeconsole_on_close (bool val);
+  void trigger_redraw_screen (void);
   void wait_pcon_fwd (void);
 };
 

diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index a92bcfc4099fd69e0fca71898d7d053ebb622096..f88382752308b3752b89267b7fd42a1fe832ae29 100644 (file)
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -80,7 +80,13 @@ set_switch_to_pcon (void)
        fhandler_base *fh = cfd;
        fhandler_pty_slave *ptys = (fhandler_pty_slave *) fh;
        if (ptys->get_pseudo_console ())
-         ptys->set_switch_to_pcon (fd);
+         {
+           ptys->set_switch_to_pcon (fd);
+           ptys->trigger_redraw_screen ();
+           DWORD mode =
+             ENABLE_PROCESSED_INPUT | ENABLE_LINE_INPUT | ENABLE_ECHO_INPUT;
+           SetConsoleMode (ptys->get_handle (), mode);
+         }
       }
 }
 
@@ -1097,9 +1103,6 @@ fhandler_pty_slave::set_switch_to_pcon (int fd_set)
        if (!try_reattach_pcon ())
          goto skip_console_setting;
       FlushConsoleInputBuffer (get_handle ());
-      DWORD mode;
-      mode = ENABLE_PROCESSED_INPUT | ENABLE_LINE_INPUT | ENABLE_ECHO_INPUT;
-      SetConsoleMode (get_handle (), mode);
 skip_console_setting:
       restore_reattach_pcon ();
       if (get_ttyp ()->pcon_pid == 0 ||
@@ -1160,7 +1163,8 @@ fhandler_pty_slave::reset_switch_to_pcon (void)
 }
 
 void
-fhandler_pty_slave::push_to_pcon_screenbuffer (const char *ptr, size_t len)
+fhandler_pty_slave::push_to_pcon_screenbuffer (const char *ptr, size_t len,
+                                              bool is_echo)
 {
   bool attached =
     !!fhandler_console::get_console_process_id (get_helper_process_id (), true);
@@ -1231,7 +1235,7 @@ fhandler_pty_slave::push_to_pcon_screenbuffer (const char *ptr, size_t len)
     }
   if (!nlen) /* Nothing to be synchronized */
     goto cleanup;
-  if (get_ttyp ()->switch_to_pcon_out)
+  if (get_ttyp ()->switch_to_pcon_out && !is_echo)
     goto cleanup;
   /* Remove ESC sequence which returns results to console
      input buffer. Without this, cursor position report
@@ -1388,7 +1392,7 @@ fhandler_pty_slave::write (const void *ptr, size_t len)
   if (get_pseudo_console ())
     {
       acquire_output_mutex (INFINITE);
-      push_to_pcon_screenbuffer ((char *)ptr, len);
+      push_to_pcon_screenbuffer ((char *)ptr, len, false);
       release_output_mutex ();
     }
 
@@ -1716,7 +1720,9 @@ out:
   if (get_pseudo_console () && ptr0 && (get_ttyp ()->ti.c_lflag & ECHO))
     {
       acquire_output_mutex (INFINITE);
-      push_to_pcon_screenbuffer (ptr0, len);
+      push_to_pcon_screenbuffer (ptr0, len, true);
+      if (get_ttyp ()->switch_to_pcon_out)
+       trigger_redraw_screen ();
       release_output_mutex ();
     }
   mask_switch_to_pcon_in (false);
@@ -2700,6 +2706,21 @@ fhandler_pty_slave::wait_pcon_fwd (void)
   cygwait (get_ttyp ()->fwd_done, INFINITE);
 }
 
+void
+fhandler_pty_slave::trigger_redraw_screen (void)
+{
+  /* Forcibly redraw screen based on console screen buffer. */
+  /* The following code triggers redrawing the screen. */
+  CONSOLE_SCREEN_BUFFER_INFO sbi;
+  GetConsoleScreenBufferInfo (get_output_handle (), &sbi);
+  SMALL_RECT rect = {0, 0,
+    (SHORT) (sbi.dwSize.X -1), (SHORT) (sbi.dwSize.Y - 1)};
+  COORD dest = {0, 0};
+  CHAR_INFO fill = {' ', 0};
+  ScrollConsoleScreenBuffer (get_output_handle (), &rect, NULL, dest, &fill);
+  get_ttyp ()->need_redraw_screen = false;
+}
+
 void
 fhandler_pty_slave::fixup_after_attach (bool native_maybe, int fd_set)
 {
@@ -2754,19 +2775,7 @@ fhandler_pty_slave::fixup_after_attach (bool native_maybe, int fd_set)
              get_ttyp ()->switch_to_pcon_out = true;
 
              if (get_ttyp ()->need_redraw_screen)
-               {
-                 /* Forcibly redraw screen based on console screen buffer. */
-                 /* The following code triggers redrawing the screen. */
-                 CONSOLE_SCREEN_BUFFER_INFO sbi;
-                 GetConsoleScreenBufferInfo (get_output_handle (), &sbi);
-                 SMALL_RECT rect = {0, 0,
-                   (SHORT) (sbi.dwSize.X -1), (SHORT) (sbi.dwSize.Y - 1)};
-                 COORD dest = {0, 0};
-                 CHAR_INFO fill = {' ', 0};
-                 ScrollConsoleScreenBuffer (get_output_handle (),
-                                            &rect, NULL, dest, &fill);
-                 get_ttyp ()->need_redraw_screen = false;
-               }
+               trigger_redraw_screen ();
            }
          init_console_handler (false);
        }