Writing udev rules - wildcards?

dolt

7/26/24, 3:52 AM

Is it possible to use wildcard characters when writing udev rules? I have multiseat and i want to assign every device (keyboard, mouse etc) that gets connected to a certain USB hub - or even better, a specific port on the front of the PC - to seat1. It's kind of cumbersome to have to redo new rules each time i swap stuff around or don't remember in which USB slot each device was connected.

Using just simple udev rules, as generated by 'loginctl attach' command:

TAG=="seat", ENV{ID_FOR_SEAT}=="usb-pci-0000_00_14_0-usb-0_5_3", ENV{ID_SEAT}="seat1"

1 + 5

usb

multiseat

udev

Marco

7/26/24, 5:08 AM

Maybe its a good idea, to add the code you have already to the question.

dolt

7/26/24, 2:40 PM

@Marco thanks, done. No idea how i didn't think of that =)

Raffa

7/26/24, 2:53 PM

UDEV rules accept some [simple shell style pattern matching](https://linux.die.net/man/8/udev) ... So, something like `usb-pci-*` should work.

Raffa

7/26/24, 3:27 PM

Also please see how pattern matching is used here: https://askubuntu.com/a/1478053/968501

dolt

7/26/24, 8:17 PM

@Raffa Thanks, i searched all manpages i could think of, including that one, except not for the phrase "pattern character" ...this is a clear case of poor documentation of udev.

Score:2

Ubuntu

Raffa

7/26/24, 3:19 PM

Is it possible to use wildcard characters when writing udev rules?

Yes, it's possible according to man udev:

Most of the fields support shell glob pattern matching and alternate patterns. The following special characters are supported:

   "*"
       Matches zero or more characters.

   "?"
       Matches any single character.

   "[]"
       Matches any single character specified within the brackets. For example, the pattern
       string "tty[SR]" would match either "ttyS" or "ttyR". Ranges are also supported via
       the "-" character. For example, to match on the range of all digits, the pattern
       "[0-9]" could be used. If the first character following the "[" is a "!", any
       characters not enclosed are matched.

   "|"
       Separates alternative patterns. For example, the pattern string "abc|x*" would match
       either "abc" or "x*".

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