2

Using this rule:

SUBSYSTEM=="tty", ATTRS{idVendor}=="10c4", ATTRS{product}=="CP2102 USB to UART Bridge Controller", SYMLINK+="usb_zwave", GROUP="dialout", MODE="0666"

Gets me this link:

lrwxrwxrwx  1 root root           7 Nov 22 22:59 usb_zwave -> ttyUSB0s

The group ownership of the link does not reflect the GROUP argument in the rule. I can correctly access the link as root, but not as another user.

Any thoughts how to resolve? Thanks

Update: requested info

root@home:/dev# sudo ls -l /dev/ttyUSB0*
crw-rw-rw-  1 root dialout      188, 0 Nov 27 20:36 /dev/ttyUSB0
7
  • Could you edit the question and add output of sudo ls -l /dev/ttyUSB0* ?
    – user.dz
    Nov 22, 2015 at 22:43
  • Just to make sure: you do reload yr rule with sudo udevadm control --reload-rules after each change and and name it with for instance "99_" as a name prefix so it is taken into account last in your chain of existing rules... Are you all clear on that ? Also look up unix.stackexchange.com/questions/124540/…. I think your answer lies right there, but if you need more assistance please add relevant info to your question by editing it.
    – Cbhihe
    Nov 24, 2015 at 8:48
  • .... and check out wiki.archlinux.org/index.php/udev.
    – Cbhihe
    Nov 24, 2015 at 8:50
  • 1
    root@home:/dev# sudo ls -l /dev/ttyUSB0* crw-rw-rw- 1 root dialout 188, 0 Nov 27 20:36 /dev/ttyUSB0
    – coyote
    Nov 27, 2015 at 19:37
  • 1
    It turned out to be complete ignorance on the inner workings of udev on my part and the inability to deal with symlinks of the application to raised the issue. Now it's clear that udev behaviour is normal: links are ALWAYS created as owned by root and fully writable. Any access restrictions need to be set on the target of the link, which is what the group argument in udev is for. Then the java application needed to be made "symlink aware" by adding -Dgnu.io.rxtx.SerialPorts=/dev/symlinkname to the JAVA_ARGS_DEFAULT section of the startup script.
    – coyote
    Nov 27, 2015 at 21:42

0

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