On Thu, Jun 14, 2007 at 11:04:51PM +0200, Blaisorblade wrote:
> On martedì 12 giugno 2007, Sylvain Beucler wrote:
> > On Mon, Jun 11, 2007 at 09:26:12PM +0000, Paolo Giarrusso wrote:
> > > If you run the open or openvt command, it will run bash on
> > > /dev/ttyXXX and there, you'll see that Ctrl-C works.
> >
> > Alas that doesn't seem to work from rootfstype:
> > # openvt /dev/tty0
> > Couldnt get a file descriptor referring to the console
> > Could not get a file descriptor referring to the console
>
> That may mean that /dev/console couldn't be opened, which is actually
> reasonable (on my system it's owned by root with perms 0600).
I replaced /dev with tmpfs + MAKEDEV console, but that doesn't help.
Well, actually I tried the command in a normal UML with a disk image
and it doesn't work either :)
> I suggested openvt for this - this area is related to session and process
> group management, and involves things like setsid(1) (and setsid(2)) and
> management of the controlling tty (I don't know the tiny details).
A more verbose output (with kernel trace) gives:
line_ioctl: tty0: ioctl KDGKBTYPE called
line_ioctl: tty0: ioctl KDGKBTYPE called
line_ioctl: tty0: ioctl KDGKBTYPE called
line_ioctl: tty0: ioctl KDGKBTYPE called
line_ioctl: tty0: ioctl KDGKBTYPE called
Couldnt get a file descriptor referring to the console
Could not get a file descriptor referring to the console
In a deboostrap:
# openvt
Couldnt get a file descriptor referring to the console
/var/log/syslog:
Jun 15 16:28:56 sylvain kernel: line_ioctl: tty3: ioctl KDGKBTYPE called
Jun 15 16:28:56 sylvain kernel: line_ioctl: tty0: ioctl KDGKBTYPE called
Jun 15 16:28:56 sylvain kernel: line_ioctl: tty3: ioctl KDGKBTYPE called
Jun 15 16:28:56 sylvain last message repeated 2 times
Jun 15 16:29:18 sylvain kernel: line_write_room: tty3: no room left in buffer
(Btw, I also see this kind of output when starting UML:
Setting console screen modes and fonts.
line_ioctl: tty0: ioctl KDGKBTYPE called
line_ioctl: tty0: ioctl KDGKBTYPE called
line_ioctl: tty0: ioctl KDGKBTYPE called
line_ioctl: tty0: ioctl KDGKBTYPE called
line_ioctl: tty0: ioctl KDGKBTYPE called
INIT: Entering runlevel: 2)
With strace and rootfstype=hostfs:
...
brk(0) = 0x804b000
brk(0x806c000) = 0x806c000
open("/dev/tty", O_RDWR) = 3
ioctl(3, KDGKBTYPE, 0xbf63d9e3) = -1 EINVAL (Invalid argument)
close(3) = 0
open("/dev/tty0", O_RDWR) = 3
ioctl(3, KDGKBTYPE, 0xbf63d9e3) = -1 EINVAL (Invalid argument)
close(3) = 0
open("/dev/console", O_RDWR) = 3
ioctl(3, KDGKBTYPE, 0xbf63d9e3) = -1 EINVAL (Invalid argument)
close(3) = 0
ioctl(0, KDGKBTYPE, 0xbf63da03) = -1 EINVAL (Invalid argument)
ioctl(1, KDGKBTYPE, 0xbf63da03) = -1 EINVAL (Invalid argument)
ioctl(2, KDGKBTYPE, 0xbf63da03) = -1 EINVAL (Invalid argument)
write(2, "Couldnt get a file descriptor re"..., 55Couldnt get a file descriptor
referring to the console
) = 55
write(2, "Could not get a file descriptor "..., 57Could not get a file
descriptor referring to the console
) = 57
exit_group(2) = ?
With strace and a disk image:
munmap(0x40019000, 8504) = 0
open("/dev/tty", O_RDONLY) = 3
ioctl(3, KDGKBTYPE, 0xbfa31f37) = -1 EINVAL (Invalid argument)
open("/dev/console", O_RDONLY) = 4
ioctl(4, KDGKBTYPE, 0xbfa31f37) = -1 EINVAL (Invalid argument)
ioctl(0, KDGKBTYPE, 0xbfa31f57) = -1 EINVAL (Invalid argument)
ioctl(1, KDGKBTYPE, 0xbfa31f57) = -1 EINVAL (Invalid argument)
ioctl(2, KDGKBTYPE, 0xbfa31f57) = -1 EINVAL (Invalid argument)
write(2, "Couldnt get a file descriptor re"..., 55Couldnt get a file descriptor
referring to the console
) = 55
exit_group(2) = ?
Process 1030 detached
So apparently this is not related to running rootfstype=hostfs.
I guess we can stick with a manual setsid(1) for now :)
--
Sylvain
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