xnu-4903.241.1.tar.gz

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

diff --git a/bsd/kern/tty_dev.c b/bsd/kern/tty_dev.c
index 87f3cd7ee6a5724eb4e940bdde1fb2e28547ee9e..1e1fe83f448d21fbe5df9436326993d83b27b8d7 100644 (file)
--- a/bsd/kern/tty_dev.c
+++ b/bsd/kern/tty_dev.c
@@ -318,7 +318,7 @@ ptsclose(dev_t dev, int flag, __unused int mode, __unused proc_t p)
        struct tty_dev_t *driver;
        struct ptmx_ioctl *pti = pty_get_ioctl(dev, 0, &driver);
        struct tty *tp;
-       
+
        if (pti == NULL)
                return (ENXIO);
 
@@ -328,9 +328,16 @@ ptsclose(dev_t dev, int flag, __unused int mode, __unused proc_t p)
        save_timeout = tp->t_timeout;
        tp->t_timeout = 60;
 #endif
+       /*
+        * Close the line discipline and backing TTY structures.
+        */
        err = (*linesw[tp->t_line].l_close)(tp, flag);
-       ptsstop(tp, FREAD|FWRITE);
-       (void) ttyclose(tp);
+       (void)ttyclose(tp);
+
+       /*
+        * Flush data and notify any waiters on the master side of this PTY.
+        */
+       ptsstop(tp, FREAD | FWRITE);
 #ifdef FIX_VSX_HANG
        tp->t_timeout = save_timeout;
 #endif
@@ -496,10 +503,12 @@ ptcwakeup(struct tty *tp, int flag)
        if (flag & FREAD) {
                selwakeup(&pti->pt_selr);
                wakeup(TSA_PTC_READ(tp));
+               KNOTE(&pti->pt_selr.si_note, 1);
        }
        if (flag & FWRITE) {
                selwakeup(&pti->pt_selw);
                wakeup(TSA_PTC_WRITE(tp));
+               KNOTE(&pti->pt_selw.si_note, 1);
        }
 }
 
@@ -554,29 +563,46 @@ ptcclose(dev_t dev, __unused int flags, __unused int fmt, __unused proc_t p)
        struct tty_dev_t *driver;
        struct ptmx_ioctl *pti = pty_get_ioctl(dev, 0, &driver);
        struct tty *tp;
+       struct knote *kn;
+
+       if (!pti) {
+               return ENXIO;
+       }
 
-       if (pti == NULL)
-               return (ENXIO);
        tp = pti->pt_tty;
        tty_lock(tp);
 
-       (void)(*linesw[tp->t_line].l_modem)(tp, 0);
-
        /*
-        * XXX MDMBUF makes no sense for ptys but would inhibit the above
-        * l_modem().  CLOCAL makes sense but isn't supported.   Special
-        * l_modem()s that ignore carrier drop make no sense for ptys but
-        * may be in use because other parts of the line discipline make
-        * sense for ptys.  Recover by doing everything that a normal
-        * ttymodem() would have done except for sending a SIGHUP.
+        * XXX MDMBUF makes no sense for PTYs, but would inhibit an `l_modem`.
+        * CLOCAL makes sense but isn't supported.  Special `l_modem`s that ignore
+        * carrier drop make no sense for PTYs but may be in use because other parts
+        * of the line discipline make sense for PTYs.  Recover by doing everything
+        * that a normal `ttymodem` would have done except for sending SIGHUP.
         */
+       (void)(*linesw[tp->t_line].l_modem)(tp, 0);
        if (tp->t_state & TS_ISOPEN) {
                tp->t_state &= ~(TS_CARR_ON | TS_CONNECTED);
                tp->t_state |= TS_ZOMBIE;
                ttyflush(tp, FREAD | FWRITE);
        }
 
-       tp->t_oproc = 0;                /* mark closed */
+       /*
+        * Null out the backing TTY struct's open procedure to prevent starting
+        * slaves through `ptsstart`.
+        */
+       tp->t_oproc = NULL;
+
+       /*
+        * Clear any select or kevent waiters under the lock.
+        */
+       SLIST_FOREACH(kn, &pti->pt_selr.si_note, kn_selnext) {
+               KNOTE_DETACH(&pti->pt_selr.si_note, kn);
+       }
+       selthreadclear(&pti->pt_selr);
+       SLIST_FOREACH(kn, &pti->pt_selw.si_note, kn_selnext) {
+               KNOTE_DETACH(&pti->pt_selw.si_note, kn);
+       }
+       selthreadclear(&pti->pt_selw);
 
        tty_unlock(tp);
 
@@ -776,10 +802,10 @@ ptcselect(dev_t dev, int rw, void *wql, proc_t p)
                }
                /* FALLTHROUGH */
 
-       case 0:                                 /* exceptional */
+       case 0: /* exceptional */
                if ((tp->t_state&TS_ISOPEN) &&
-                   ((pti->pt_flags & PF_PKT && pti->pt_send) ||
-                    (pti->pt_flags & PF_UCNTL && pti->pt_ucntl))) {
+                               (((pti->pt_flags & PF_PKT) && pti->pt_send) ||
+                                ((pti->pt_flags & PF_UCNTL) && pti->pt_ucntl))) {
                        retval = 1;
                        break;
                }
@@ -790,21 +816,21 @@ ptcselect(dev_t dev, int rw, void *wql, proc_t p)
        case FWRITE:
                if (tp->t_state&TS_ISOPEN) {
                        if (pti->pt_flags & PF_REMOTE) {
-                           if (tp->t_canq.c_cc == 0) {
-                               retval = (driver->fix_7828447) ? (TTYHOG - 1) : 1;
-                               break;
+                               if (tp->t_canq.c_cc == 0) {
+                                       retval = (driver->fix_7828447) ? (TTYHOG - 1) : 1;
+                                       break;
                            }
                        } else {
-                           retval = (TTYHOG - 2) - (tp->t_rawq.c_cc + tp->t_canq.c_cc);
-                           if (retval > 0) {
-                                   retval = (driver->fix_7828447) ? retval : 1;
-                                   break;
-                           }
-                           if (tp->t_canq.c_cc == 0 && (tp->t_lflag&ICANON)) {
-                                   retval = 1;
-                                   break;
-                           }
-                           retval = 0;
+                               retval = (TTYHOG - 2) - (tp->t_rawq.c_cc + tp->t_canq.c_cc);
+                               if (retval > 0) {
+                                       retval = (driver->fix_7828447) ? retval : 1;
+                                       break;
+                               }
+                               if (tp->t_canq.c_cc == 0 && (tp->t_lflag&ICANON)) {
+                                       retval = 1;
+                                       break;
+                               }
+                               retval = 0;
                        }
                }
                selrecord(p, &pti->pt_selw, wql);