On Thu, Jan 09, 2003 at 03:05:56PM -0800, Ed Vance wrote: > On Thu, Jan 09, 2003 at 2:21 PM, Jan Hudec wrote: > > I think, that it's a bit different. It should look like following: > > process A has pty/1 as ctty. > > process A makes pty/1 available (presumably via TIOCNOTTY) > > process B has no ctty (there is something about setsid I don't fully > > understand) > > process A tells process B that it can use pty/1 > > process B opens pty/1 and makes it it's controling terminal > > (TIOCSCTTY) > > > > The reason behind this: I have a process that logs a LOT to > > stdout/stderr, does "setterm" ioctls on it and needs WINCH > > signal (thus a controling tty). I want to run it from gdb > > and have gdb and this programs output separated. Thus I use > > gdb's tty command. But I need to make a tty available (under > > X, that is in some terminal emulator). > > > > If B calls setsid() successfully, then B opening pty/1 should > make pty/1 ctty of B. Should not need to use TIOCSCTTY ioctl > unless pty/1 still has a session attached, which it will if > process A was not the session leader. Then you would not need > the TIOCNOTTY and would need to use TIOCSCTTY with arg=1 to > wrestle pty/1 away from its current group. Which call is > returning an error? The TIOCSCTTY. The problem is, that TIOCSCTTY with arg=1 only works for superuser (at least seems so from kernel source). Thus I need to detach the terminal properly... ------------------------------------------------------------------------------- Jan 'Bulb' Hudec <bulb@ucw.cz> -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
