xnu-1699.32.7.tar.gz

[apple/xnu.git] / bsd / kern / tty.c

diff --git a/bsd/kern/tty.c b/bsd/kern/tty.c
index 8417816125e71259ccae35d7123c6ab7834f9b6e..b97eb780e36ea557e667a64c90a19e204a4ad06d 100644 (file)
--- a/bsd/kern/tty.c
+++ b/bsd/kern/tty.c
@@ -1498,6 +1498,8 @@ out:
 int
 ttyselect(struct tty *tp, int rw, void *wql, proc_t p)
 {
 int
 ttyselect(struct tty *tp, int rw, void *wql, proc_t p)
 {

+       int retval = 0;
+

        if (tp == NULL)
                return (ENXIO);
 
        if (tp == NULL)
                return (ENXIO);
 


@@ -1505,20 +1507,32 @@ ttyselect(struct tty *tp, int rw, void *wql, proc_t p)
 
        switch (rw) {
        case FREAD:
 
        switch (rw) {
        case FREAD:

-               if (ttnread(tp) > 0 || ISSET(tp->t_state, TS_ZOMBIE))
+               if (ISSET(tp->t_state, TS_ZOMBIE)) {

                        return(1);
                        return(1);

+               }
+
+               retval = ttnread(tp);
+               if (retval > 0) {
+                       break;
+               }
+

                selrecord(p, &tp->t_rsel, wql);
                break;
        case FWRITE:
                selrecord(p, &tp->t_rsel, wql);
                break;
        case FWRITE:

-               if ((tp->t_outq.c_cc <= tp->t_lowat &&
-                    ISSET(tp->t_state, TS_CONNECTED))
-                   || ISSET(tp->t_state, TS_ZOMBIE)) {
-                       return (1);
+               if (ISSET(tp->t_state, TS_ZOMBIE)) {
+                       return(1);

                }
                }

+
+               if ((tp->t_outq.c_cc <= tp->t_lowat) &&
+                               ISSET(tp->t_state, TS_CONNECTED)) {
+                       retval = tp->t_hiwat - tp->t_outq.c_cc;
+                       break;
+               }
+

                selrecord(p, &tp->t_wsel, wql);
                break;
        }
                selrecord(p, &tp->t_wsel, wql);
                break;
        }

-       return (0);
+       return retval;

 }
 
 
 }
 
 


@@ -3040,6 +3054,12 @@ ttyfree(struct tty *tp)
 {
        TTY_LOCK_NOTOWNED(tp);  /* debug assert */
 
 {
        TTY_LOCK_NOTOWNED(tp);  /* debug assert */
 

+#if DEBUG
+       if (!(SLIST_EMPTY(&tp->t_rsel.si_note) && SLIST_EMPTY(&tp->t_wsel.si_note))) {
+               panic("knotes hooked into a tty when the tty is freed.\n");
+       }
+#endif /* DEBUG */
+

        clfree(&tp->t_rawq);
        clfree(&tp->t_canq);
        clfree(&tp->t_outq);
        clfree(&tp->t_rawq);
        clfree(&tp->t_canq);
        clfree(&tp->t_outq);