diff options
Diffstat (limited to 'winsup/cygwin/fhandler_termios.cc')
| -rw-r--r-- | winsup/cygwin/fhandler_termios.cc | 43 |
1 files changed, 37 insertions, 6 deletions
diff --git a/winsup/cygwin/fhandler_termios.cc b/winsup/cygwin/fhandler_termios.cc index 8bbe301ad..dc8a19b02 100644 --- a/winsup/cygwin/fhandler_termios.cc +++ b/winsup/cygwin/fhandler_termios.cc @@ -166,14 +166,43 @@ tty_min::is_orphaned_process_group (int pgid) return 1; } +/* + bg_check: check that this process is either in the foreground process group, + or if the terminal operation is allowed for processes which are in a + background process group. + + If the operation is not permitted by the terminal configuration for processes + which are a member of a background process group, return an error or raise a + signal as appropriate. + + This handles the following terminal operations: + + write: sig = SIGTTOU + read: sig = SIGTTIN + change terminal settings: sig = -SIGTTOU + (tcsetattr, tcsetpgrp, etc.) + peek (poll, select): sig = SIGTTIN, dontsignal = TRUE +*/ bg_check_types -fhandler_termios::bg_check (int sig) +fhandler_termios::bg_check (int sig, bool dontsignal) { + /* Ignore errors: + - this process isn't in a process group + - tty is invalid + + Everything is ok if: + - this process is in the foreground process group, or + - this tty is not the controlling tty for this process (???), or + - writing, when TOSTOP TTY mode is not set on this tty + */ if (!myself->pgid || !tc () || tc ()->getpgid () == myself->pgid || myself->ctty != tc ()->ntty || ((sig == SIGTTOU) && !(tc ()->ti.c_lflag & TOSTOP))) return bg_ok; + /* sig -SIGTTOU is used to indicate a change to terminal settings, where + TOSTOP TTY mode isn't considered when determining if we need to send a + signal. */ if (sig < 0) sig = -sig; @@ -197,19 +226,20 @@ fhandler_termios::bg_check (int sig) (_main_tls->sigmask & SIGTOMASK (sig)); cygheap->unlock_tls (tl_entry); - /* If the process is ignoring SIGTT*, then background IO is OK. If - the process is not ignoring SIGTT*, then the sig is to be sent to - all processes in the process group (unless the process group of the - process is orphaned, in which case we return EIO). */ + /* If the process is blocking or ignoring SIGTT*, then signals are not sent + and background IO is allowed */ if (sigs_ignored) return bg_ok; /* Just allow the IO */ + /* If the process group of the process is orphaned, return EIO */ else if (tc ()->is_orphaned_process_group (myself->pgid)) { termios_printf ("process group is orphaned"); set_errno (EIO); /* This is an IO error */ return bg_error; } - else + /* Otherwise, if signalling is desired, the signal is sent to all processes in + the process group */ + else if (!dontsignal) { /* Don't raise a SIGTT* signal if we have already been interrupted by another signal. */ @@ -222,6 +252,7 @@ fhandler_termios::bg_check (int sig) } return bg_signalled; } + return bg_ok; } #define set_input_done(x) input_done = input_done || (x) |