At Wed, 2 May 2012 16:27:48 +0000 CentOS mailing list centos@centos.org wrote:
Can someone please help me with writing a udev rule?
I need /dev/ttyUSB0 to automatically have 777 rights when plugged in. I'd like it to only apply to that one specific device.
I'm not sure where to start, what files to look at and also what to write to make it work.
Does this give you a clue:
sauron.deepsoft.com% cat /etc/udev/rules.d/10-local.rules #KERNEL="ttyS0", SYMLINK="mouse" #KERNEL="mice", NAME="input/%k",SYMLINK="mouse" KERNEL=="ttyS4", SYMLINK="modem" KERNEL=="ttyS5", SYMLINK="back", MODE="0666" KERNEL=="ttyS7", SYMLINK="front", MODE="0666" #KERNEL=="sr[0-9]*", GROUP="disk", MODE="0666" #KERNEL=="scd[0-9]*", GROUP="disk", MODE="0666" #KERNEL=="hd[a-z]", BUS=="ide", SYSFS{removable}=="1", PROGRAM=="check-cdrom.sh %k DVD", SYMLINK+="dvdrom" KERNEL=="sd[a-z]*", BUS=="scsi", SYSFS{vendor}=="Kingston", NAME="thumb"
Things to note: '/dev/ttyUSB0' is probably not a good name (I get away with ttyS4, ttyS5, and ttyS7, since these are not hotplugable devices (they are on a 4 port PCI card). Anything subject to hot pluging (like my Kingston thum drive), should probably be using a NAME or SYMLINK directive and be testing on something like a SYSFS{vendor} or something. Each time you plug it in the name could change, depending on what else is plugged in at the time.
You probably want something like:
KERNEL=="ttyUSB*", BUS=="usb", SYSFS{vendor}=="whatever", MODE="0777", SYMLINK="USBSerialPort"
Put this in /etc/udev/rules.d/10-local.rules
Replace 'whatever' with the vendor name or use SYSFS{idVendor} and the hex code, possibly also with a SYSFS{idProduct} test as well. You can find out what works for the SYSFS keys by looking in /sys/bus/usb/devices/usb*/* -- the keys are the names of the files and the values to test for are the contents of these 'files'.
TIA
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