Re: /dev/ptmx suid root tty device file - Who owns this?
On Wed, Apr 10, 2002 at 05:51:30AM -0700, David D. W. Downey wrote:
> I know that a grep -i ptmx -r kernel-source-2.4.18/ will show a
> Pseudo-tty which is fine. The devices.txt shows that it's a Master pty
> for the pty master multiplex, and the lettering positions within the pty array
That's what it is.
> I'm looking to find out what it's specific usage is, as in at the device
> level is this a template file used to carbon the ttys off of? If not, why
> is it set for the global array for the entire x series? Or is this file
> acting as a device fifo for IPC processes?
There is a protocol, I'm not sure. Most people use the makepty() system call
which hides all the magic in glibc.
> I've run this against woody and sid with no ownership found. Other than
> it being part of the base*.tgz I can't see what package owns it or any
> other data on it other than device type.
Look into MAKEDEV. It has instructions for creating hundreds of devices.
Also, if you have devfs it will be created by the kernel.
> I do see in the man page that it says some devices will not be
> recorded as being owned by a package if it was created by a postinst, I
> don't see in any of the install or system logs this device being
> created. So to me that begs the question, who owns this file's creation?
> Anyone out there know what package(s) specificly create(s) this device?
I think it's in base*.tgz precisely because if you delete it, you'll
probably not be able login remotely. It's not really owned by anybody,
because it needs to exist before ownership is meaningful (if you get what I
Martijn van Oosterhout <email@example.com> http://svana.org/kleptog/
> Ignorance continues to thrive when intelligent people choose to do
> nothing. Speaking out against censorship and ignorance is the imperative
> of all intelligent people.
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