multi-user, udev, consolkit, oh my
I'm working on multi-user setups.
I'd like to be assign some resources - like a USB hub - to a seat and have hotplug for that hub work only for that seat.
Currently, what happens is that a user plugs in a camera, and hal reports the event. All of the concurrent gnome-volume-manager instances then try to grab that resource, and what results is a mess.
consolekit has been suggested as a way to resolve this, but I can't figure out how to use it.
googling around, I've found suggestions for using udev to limit access to usb devices by creating a group that only has access to the usb subsystem.
If I want to group some resources and only have those resources on behalf of a specific user, and not any other, is there a way to do that? Can I set up groups for hotplugging usb devices and set it up so that the event is only reported to specific group members?
Thanks.,
--Yan
Quoted 11 lines · Yan Seiner
I'm working on multi-user setups.
I'd like to be assign some resources - like a USB hub - to a seat and have hotplug for that hub work only for that seat.
Currently, what happens is that a user plugs in a camera, and hal reports the event. All of the concurrent gnome-volume-manager instances then try to grab that resource, and what results is a mess.
consolekit has been suggested as a way to resolve this, but I can't figure out how to use it.
Yes, ConsoleKit/PolicyKit/HAL should be used as the basic infrastructure to properly assign ACL's to devices for specific users. ConsoleKit is the only way to track activitty of sessions, which is what you need for shared devices, to grant access only to active sessions. But I don't think anybody ever really used multi-seat setups, so there is likely stuff that needs to be implemented.
Quoted 5 lines
googling around, I've found suggestions for using udev to limit access to usb devices by creating a group that only has access to the usb subsystem.
If I want to group some resources and only have those resources on behalf of a specific user, and not any other, is there a way to do that?
You can assign an owner or group to all devices below a specific USB hub. You onlt need to identify the hub reliably.
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Can I set up groups for hotplugging usb devices
You can assign owners/groups to specific devices, based on matches od properties of the devices, but you can not setup "groups for hotplugging".
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and set it up so that the event is only reported to specific group members?
There are no user specific events, udev acts at the system level, just like the kernel, it has no idea who receives which event.
Kay
Quoted 26 lines · Kay Sievers
Quoted 5 lines · Yan Seiner
I'm working on multi-user setups.
I'd like to be assign some resources - like a USB hub - to a seat and have hotplug for that hub work only for that seat.
Quoted 7 lines
Currently, what happens is that a user plugs in a camera, and hal reports the event. All of the concurrent gnome-volume-manager instances then try to grab that resource, and what results is a mess.
consolekit has been suggested as a way to resolve this, but I can't figure out how to use it.
Yes, ConsoleKit/PolicyKit/HAL should be used as the basic infrastructure to properly assign ACL's to devices for specific users. ConsoleKit is the only way to track activitty of sessions, which is what you need for shared devices, to grant access only to active sessions. But I don't think anybody ever really used multi-seat setups, so there is likely stuff that needs to be implemented.
Quoted 3 lines
googling around, I've found suggestions for using udev to limit access to usb devices by creating a group that only has access to the usb subsystem.
Quoted 8 lines
Quoted 3 lines
If I want to group some resources and only have those resources on behalf of a specific user, and not any other, is there a way to do that?
You can assign an owner or group to all devices below a specific USB hub. You onlt need to identify the hub reliably.
Thanks for the information. At least I'm on the right track... I've been reading up on dbus and hal, but I can't really find how dbus, ConsoleKit, and hal all work together. It looks like the policies in /etc/dbus-1/session.conf might do what I need, but I can't find any documentation on what policies are available and how to set them.
The overall idea is that we put up an X session on every available screen and ask the user to hit a specific key on the keyboard. The key is different for each X session. Once we have the keyboard event, we can tell which USB hub it came from and we can assign the USB hub it's plugged into to that seat. We can then scan the hub for mouse, audio, mass storage, whatever and handle them on behalf of that user.
From that point on, any event that takes place on that hub only gets
handled by that user's session. That's the long-term goal. Right now it would be nice just to be able to limit gnome-volume-manager to a single hub, even if I have to hard-code the hub in some config file.
I'm new to the whole dbus/hal thing so I would appreciate any pointers to docs or discussion that might help me out.
--Yan