[project @ 2003-09-24 10:32:12 by simonmar]

If we change the terminal settings as a result of hSetBuffering or
hSetEcho, then restore them again in hs_exit().  This is just good
citizenship on Unixy platforms.

We *don't* just automatically save the terminal settings and restore
them at the end, because that would prevent implementing stty-like
programs in Haskell.  This scheme is a compromise that hopefully DTRT
in most cases.

diff --git a/System/Posix/Internals.hs b/System/Posix/Internals.hs
index 3cdb618..ff07615 100644 (file)
--- a/System/Posix/Internals.hs
+++ b/System/Posix/Internals.hs
@@ -173,29 +173,22 @@ fdIsTTY fd = c_isatty (fromIntegral fd) >>= return.toBool
 
 setEcho :: Int -> Bool -> IO ()
 setEcho fd on = do
-  allocaBytes sizeof_termios  $ \p_tios -> do
-    throwErrnoIfMinus1Retry "setEcho"
-       (c_tcgetattr (fromIntegral fd) p_tios)
+  tcSetAttr fd $ \ p_tios -> do
     c_lflag <- c_lflag p_tios :: IO CTcflag
     let new_c_lflag
         | on        = c_lflag .|. fromIntegral const_echo
         | otherwise = c_lflag .&. complement (fromIntegral const_echo)
     poke_c_lflag p_tios (new_c_lflag :: CTcflag)
-    tcSetAttr fd const_tcsanow p_tios
 
 getEcho :: Int -> IO Bool
 getEcho fd = do
-  allocaBytes sizeof_termios  $ \p_tios -> do
-    throwErrnoIfMinus1Retry "setEcho"
-       (c_tcgetattr (fromIntegral fd) p_tios)
+  tcSetAttr fd $ \ p_tios -> do
     c_lflag <- c_lflag p_tios :: IO CTcflag
     return ((c_lflag .&. fromIntegral const_echo) /= 0)
 
 setCooked :: Int -> Bool -> IO ()
 setCooked fd cooked = 
-  allocaBytes sizeof_termios  $ \p_tios -> do
-    throwErrnoIfMinus1Retry "setCooked"
-       (c_tcgetattr (fromIntegral fd) p_tios)
+  tcSetAttr fd $ \ p_tios -> do
 
     -- turn on/off ICANON
     c_lflag <- c_lflag p_tios :: IO CTcflag
@@ -211,25 +204,38 @@ setCooked fd cooked =
            poke vmin  1
            poke vtime 0
 
-    tcSetAttr fd const_tcsanow p_tios
-
--- tcsetattr() when invoked by a background process causes the process
--- to be sent SIGTTOU regardless of whether the process has TOSTOP set
--- in its terminal flags (try it...).  This function provides a
--- wrapper which temporarily blocks SIGTTOU around the call, making it
--- transparent.
-
-tcSetAttr :: FD -> CInt -> Ptr CTermios -> IO ()
-tcSetAttr fd options p_tios = do
-  allocaBytes sizeof_sigset_t $ \ p_sigset -> do
-  allocaBytes sizeof_sigset_t $ \ p_old_sigset -> do
-     c_sigemptyset p_sigset
-     c_sigaddset   p_sigset const_sigttou
-     c_sigprocmask const_sig_block p_sigset p_old_sigset
-     throwErrnoIfMinus1Retry_ "tcSetAttr" $
-        c_tcsetattr (fromIntegral fd) options p_tios
-     c_sigprocmask const_sig_setmask p_old_sigset nullPtr
-     return ()
+tcSetAttr :: FD -> (Ptr CTermios -> IO a) -> IO a
+tcSetAttr fd fun = do
+     allocaBytes sizeof_termios  $ \p_tios -> do
+       throwErrnoIfMinus1Retry "tcSetAttr"
+          (c_tcgetattr (fromIntegral fd) p_tios)
+
+       -- Save a copy of termios, if this is a standard file descriptor.
+       -- These terminal settings are restored in hs_exit().
+       when (fd <= 2) $ do
+         p <- peekElemOff saved_termios fd
+         when (p == nullPtr) $ do
+            saved_tios <- mallocBytes sizeof_termios
+            copyBytes saved_tios p_tios sizeof_termios
+            pokeElemOff saved_termios fd saved_tios
+
+       -- tcsetattr() when invoked by a background process causes the process
+       -- to be sent SIGTTOU regardless of whether the process has TOSTOP set
+       -- in its terminal flags (try it...).  This function provides a
+       -- wrapper which temporarily blocks SIGTTOU around the call, making it
+       -- transparent.
+       allocaBytes sizeof_sigset_t $ \ p_sigset -> do
+       allocaBytes sizeof_sigset_t $ \ p_old_sigset -> do
+            c_sigemptyset p_sigset
+            c_sigaddset   p_sigset const_sigttou
+            c_sigprocmask const_sig_block p_sigset p_old_sigset
+            r <- fun p_tios  -- do the business
+            throwErrnoIfMinus1Retry_ "tcSetAttr" $
+                c_tcsetattr (fromIntegral fd) const_tcsanow p_tios
+            c_sigprocmask const_sig_setmask p_old_sigset nullPtr
+            return r
+
+foreign import ccall "&saved_termios" saved_termios :: Ptr (Ptr CTermios)
 
 #else
 

diff --git a/include/HsBase.h b/include/HsBase.h
index e091f14..47d028d 100644 (file)
--- a/include/HsBase.h
+++ b/include/HsBase.h
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: HsBase.h,v 1.27 2003/09/21 22:20:57 wolfgang Exp $
+ * $Id: HsBase.h,v 1.28 2003/09/24 10:32:12 simonmar Exp $
  *
  * (c) The University of Glasgow 2001-2002
  *
@@ -617,6 +617,11 @@ __hscore_f_setfl( void )
 #endif
 }
 
+#if HAVE_TERMIOS_H
+// defined in rts/RtsStartup.c.
+extern struct termios saved_termios[];
+#endif
+
 INLINE int __hscore_hs_fileno (FILE *f) { return fileno (f); }
 
 #ifndef mingw32_TARGET_OS