diff options
| author | bde <bde@FreeBSD.org> | 2000-01-25 09:20:08 +0000 |
|---|---|---|
| committer | bde <bde@FreeBSD.org> | 2000-01-25 09:20:08 +0000 |
| commit | 59f42795e8ec265c2a666a4fc5eb5ff6c39993c6 (patch) | |
| tree | 8a8d7d6a29e79578de834cde08de8e7b7fe86112 /sys/kern/tty_cons.c | |
| parent | 9fe8ef8eba8dbc462adbfdf1c4133940401221fb (diff) | |
| download | FreeBSD-src-59f42795e8ec265c2a666a4fc5eb5ff6c39993c6.zip FreeBSD-src-59f42795e8ec265c2a666a4fc5eb5ff6c39993c6.tar.gz | |
Don't follow null pointers if we somehow have a null devswitch entry
despite having a non-null cn_tab entry. This case now works the same
as if there is no physical console, except i/o at the kernel printf
level may still work. This frees drivers of physical console drivers
from the responsibility of attaching the device no matter what.
Diffstat (limited to 'sys/kern/tty_cons.c')
| -rw-r--r-- | sys/kern/tty_cons.c | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/sys/kern/tty_cons.c b/sys/kern/tty_cons.c index 39ce6fe..080e1aa 100644 --- a/sys/kern/tty_cons.c +++ b/sys/kern/tty_cons.c @@ -165,10 +165,12 @@ cninit_finish() * Hook the open and close functions. */ cdp = devsw(cn_tab->cn_dev); - cn_phys_close = cdp->d_close; - cdp->d_close = cnclose; - cn_phys_open = cdp->d_open; - cdp->d_open = cnopen; + if (cdp != NULL) { + cn_phys_close = cdp->d_close; + cdp->d_close = cnclose; + cn_phys_open = cdp->d_open; + cdp->d_open = cnopen; + } cn_dev_t = cn_tab->cn_dev; cn_udev_t = dev2udev(cn_dev_t); } @@ -185,9 +187,11 @@ cnuninit(void) * Unhook the open and close functions. */ cdp = devsw(cn_tab->cn_dev); - cdp->d_close = cn_phys_close; + if (cdp != NULL) { + cdp->d_close = cn_phys_close; + cdp->d_open = cn_phys_open; + } cn_phys_close = NULL; - cdp->d_open = cn_phys_open; cn_phys_open = NULL; cn_dev_t = NODEV; cn_udev_t = NOUDEV; @@ -250,7 +254,7 @@ cnopen(dev, flag, mode, p) dev_t cndev, physdev; int retval = 0; - if (cn_tab == NULL) + if (cn_tab == NULL || cn_phys_open == NULL) return (0); cndev = cn_tab->cn_dev; physdev = (major(dev) == major(cndev) ? dev : cndev); @@ -287,7 +291,7 @@ cnclose(dev, flag, mode, p) dev_t cndev; struct tty *cn_tp; - if (cn_tab == NULL) + if (cn_tab == NULL || cn_phys_open == NULL) return (0); cndev = cn_tab->cn_dev; cn_tp = cndev->si_tty; @@ -327,7 +331,8 @@ cnread(dev, uio, flag) struct uio *uio; int flag; { - if ((cn_tab == NULL) || cn_mute) + + if (cn_tab == NULL || cn_phys_open == NULL) return (0); dev = cn_tab->cn_dev; return ((*devsw(dev)->d_read)(dev, uio, flag)); @@ -339,7 +344,8 @@ cnwrite(dev, uio, flag) struct uio *uio; int flag; { - if ((cn_tab == NULL) || cn_mute) { + + if (cn_tab == NULL || cn_phys_open == NULL) { uio->uio_resid = 0; /* dump the data */ return (0); } @@ -360,7 +366,7 @@ cnioctl(dev, cmd, data, flag, p) { int error; - if ((cn_tab == NULL) || cn_mute) + if (cn_tab == NULL || cn_phys_open == NULL) return (0); /* * Superuser can always use this to wrest control of console |
