Re: [Qemu-devel] PATCH: Put Psuedo-TTY in rawmode for char devices

[Samuel Thibault <samuel.thibault@ens-lyon.org>]

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Aurelien Jarno, le Sun 04 May 2008 01:08:50 +0200, a écrit :
> On Thu, May 01, 2008 at 06:14:24PM +0100, Daniel P. Berrange wrote:
> > Re-posting patch for review/inclusion...
> > 
> > On Tue, Apr 22, 2008 at 01:50:57AM +0100, Daniel P. Berrange wrote:
> > > If running a QEMU instance with a serial/parallel device connected to a
> > > Psuedo-TTY, eg  '-serial pty',  every \r\n sequence output by the guest
> > > is getting translated into a \n\n sequence by the TTY layer. So clients
> > > interacting with the serial port via a TTY done get the correct \r\n
> > > sequence and text marches to the right and wraps. This is because the 
> > > TTY is not put into rawmode when QEMU sets it up. 
> > > 
> > > The following patch is a re-diff of a patch applied to Xen's QEMU code.
> > > It uses cfmakeraw() to ensure the TTY is put into rawmode, thus avoiding
> > > the incorrect \r\n translations. It also switches to tcsetattr() on the
> > > slave_fd instead of master_fd - although this is effectively the same on
> > > Linux, only slave_fd works on Solaris. Finally it stops using the 'name'
> > > arg to openpty() which is a security risk because its buffer size is
> > > undefined. Instead it makes use of the ptsname() function.
> > 
> 
> cfmakeraw() is Linux specific, though also available on most BSD
> systems. It is unavailable on Solaris, and probably the same on WIN32.

Indeed, in Xen we keep a local definition of cfmakeraw for the solaris
case.  That being said, the same lines as term_init could be added, see
attached patch.

Samuel

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Index: vl.c
===================================================================
--- vl.c	(r�vision 4294)
+++ vl.c	(copie de travail)
@@ -2285,7 +2285,11 @@
 
     /* Disabling local echo and line-buffered output */
     tcgetattr (master_fd, &tty);
-    tty.c_lflag &= ~(ECHO|ICANON|ISIG);
+    tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
+                          |INLCR|IGNCR|ICRNL|IXON);
+    tty.c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
+    tty.c_cflag &= ~(CSIZE|PARENB);
+    tty.c_cflag |= CS8;
     tty.c_cc[VMIN] = 1;
     tty.c_cc[VTIME] = 0;
     tcsetattr (master_fd, TCSAFLUSH, &tty);