12

I wrote this rule for testing purpose:

SUBSYSTEMS=="usb", ATTRS{manufacturer}=="Kingston", ATTRS{serial}=="001CC0EC34A2BB318709004B", ATTRS{idVendor}=="0951", ATTRS{idProduct}=="1642", SYMLINK+="pen", NAME="pendrak"

based on the following info:

# udevadm info --name=/dev/sdb --attribute-walk

Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.

  looking at device '/devices/pci0000:00/0000:00:1d.7/usb2/2-5/2-5:1.0/host2/target2:0:0/2:0:0:0/block/sdb':
    KERNEL=="sdb"
    SUBSYSTEM=="block"
    DRIVER==""
    ATTR{ro}=="0"
    ATTR{size}=="30299520"
    ATTR{stat}=="     419        0     3352     1208        0        0        0        0        0     1120     1208"
    ATTR{range}=="16"
    ATTR{discard_alignment}=="0"
    ATTR{events}=="media_change"
    ATTR{ext_range}=="256"
    ATTR{events_poll_msecs}=="3000"
    ATTR{alignment_offset}=="0"
    ATTR{inflight}=="       0        0"
    ATTR{removable}=="1"
    ATTR{capability}=="51"
    ATTR{events_async}==""

  looking at parent device '/devices/pci0000:00/0000:00:1d.7/usb2/2-5/2-5:1.0/host2/target2:0:0/2:0:0:0':
    KERNELS=="2:0:0:0"
    SUBSYSTEMS=="scsi"
    DRIVERS=="sd"
    ATTRS{rev}=="PMAP"
    ATTRS{type}=="0"
    ATTRS{scsi_level}=="0"
    ATTRS{model}=="DT 101 G2       "
    ATTRS{state}=="running"
    ATTRS{queue_type}=="none"
    ATTRS{iodone_cnt}=="0x2da"
    ATTRS{iorequest_cnt}=="0x2da"
    ATTRS{evt_capacity_change_reported}=="0"
    ATTRS{timeout}=="30"
    ATTRS{evt_media_change}=="0"
    ATTRS{max_sectors}=="240"
    ATTRS{ioerr_cnt}=="0x2"
    ATTRS{queue_depth}=="1"
    ATTRS{vendor}=="Kingston"
    ATTRS{evt_soft_threshold_reached}=="0"
    ATTRS{device_blocked}=="0"
    ATTRS{evt_mode_parameter_change_reported}=="0"
    ATTRS{evt_lun_change_reported}=="0"
    ATTRS{evt_inquiry_change_reported}=="0"
    ATTRS{iocounterbits}=="32"
    ATTRS{eh_timeout}=="10"

  looking at parent device '/devices/pci0000:00/0000:00:1d.7/usb2/2-5/2-5:1.0/host2/target2:0:0':
    KERNELS=="target2:0:0"
    SUBSYSTEMS=="scsi"
    DRIVERS==""

  looking at parent device '/devices/pci0000:00/0000:00:1d.7/usb2/2-5/2-5:1.0/host2':
    KERNELS=="host2"
    SUBSYSTEMS=="scsi"
    DRIVERS==""

  looking at parent device '/devices/pci0000:00/0000:00:1d.7/usb2/2-5/2-5:1.0':
    KERNELS=="2-5:1.0"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb-storage"
    ATTRS{bInterfaceClass}=="08"
    ATTRS{bInterfaceSubClass}=="06"
    ATTRS{bInterfaceProtocol}=="50"
    ATTRS{bNumEndpoints}=="02"
    ATTRS{supports_autosuspend}=="1"
    ATTRS{bAlternateSetting}==" 0"
    ATTRS{bInterfaceNumber}=="00"

  looking at parent device '/devices/pci0000:00/0000:00:1d.7/usb2/2-5':
    KERNELS=="2-5"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{devpath}=="5"
    ATTRS{idVendor}=="0951"
    ATTRS{speed}=="480"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{busnum}=="2"
    ATTRS{devnum}=="4"
    ATTRS{configuration}==""
    ATTRS{bMaxPower}=="200mA"
    ATTRS{authorized}=="1"
    ATTRS{bmAttributes}=="80"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{maxchild}=="0"
    ATTRS{bcdDevice}=="0100"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{serial}=="001CC0EC34A2BB318709004B"
    ATTRS{version}==" 2.00"
    ATTRS{urbnum}=="1927"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="Kingston"
    ATTRS{removable}=="unknown"
    ATTRS{idProduct}=="1642"
    ATTRS{bDeviceClass}=="00"
    ATTRS{product}=="DT 101 G2"

  looking at parent device '/devices/pci0000:00/0000:00:1d.7/usb2':
    KERNELS=="usb2"
    SUBSYSTEMS=="usb"
    DRIVERS=="usb"
    ATTRS{bDeviceSubClass}=="00"
    ATTRS{bDeviceProtocol}=="00"
    ATTRS{devpath}=="0"
    ATTRS{idVendor}=="1d6b"
    ATTRS{speed}=="480"
    ATTRS{bNumInterfaces}==" 1"
    ATTRS{bConfigurationValue}=="1"
    ATTRS{bMaxPacketSize0}=="64"
    ATTRS{authorized_default}=="1"
    ATTRS{busnum}=="2"
    ATTRS{devnum}=="1"
    ATTRS{configuration}==""
    ATTRS{bMaxPower}=="0mA"
    ATTRS{authorized}=="1"
    ATTRS{bmAttributes}=="e0"
    ATTRS{bNumConfigurations}=="1"
    ATTRS{maxchild}=="8"
    ATTRS{bcdDevice}=="0312"
    ATTRS{avoid_reset_quirk}=="0"
    ATTRS{quirks}=="0x0"
    ATTRS{serial}=="0000:00:1d.7"
    ATTRS{version}==" 2.00"
    ATTRS{urbnum}=="89"
    ATTRS{ltm_capable}=="no"
    ATTRS{manufacturer}=="Linux 3.12-1-amd64 ehci_hcd"
    ATTRS{removable}=="unknown"
    ATTRS{idProduct}=="0002"
    ATTRS{bDeviceClass}=="09"
    ATTRS{product}=="EHCI Host Controller"

  looking at parent device '/devices/pci0000:00/0000:00:1d.7':
    KERNELS=="0000:00:1d.7"
    SUBSYSTEMS=="pci"
    DRIVERS=="ehci-pci"
    ATTRS{irq}=="23"
    ATTRS{subsystem_vendor}=="0x1458"
    ATTRS{broken_parity_status}=="0"
    ATTRS{class}=="0x0c0320"
    ATTRS{companion}==""
    ATTRS{consistent_dma_mask_bits}=="32"
    ATTRS{dma_mask_bits}=="32"
    ATTRS{local_cpus}=="00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000003"
    ATTRS{device}=="0x27cc"
    ATTRS{uframe_periodic_max}=="100"
    ATTRS{enable}=="1"
    ATTRS{msi_bus}==""
    ATTRS{local_cpulist}=="0-1"
    ATTRS{vendor}=="0x8086"
    ATTRS{subsystem_device}=="0x5006"
    ATTRS{numa_node}=="-1"
    ATTRS{d3cold_allowed}=="1"

  looking at parent device '/devices/pci0000:00':
    KERNELS=="pci0000:00"
    SUBSYSTEMS==""
    DRIVERS==""

and:

# udevadm info --name=/dev/sdb
P: /devices/pci0000:00/0000:00:1d.7/usb2/2-5/2-5:1.0/host2/target2:0:0/2:0:0:0/block/sdb
N: sdb
S: disk/by-id/usb-Kingston_DT_101_G2_001CC0EC34A2BB318709004B-0:0
S: disk/by-path/pci-0000:00:1d.7-usb-0:5:1.0-scsi-0:0:0:0
S: pen
E: DEVLINKS=/dev/disk/by-id/usb-Kingston_DT_101_G2_001CC0EC34A2BB318709004B-0:0 /dev/disk/by-path/pci-0000:00:1d.7-usb-0:5:1.0-scsi-0:0:0:0 /dev/pen
E: DEVNAME=/dev/sdb
E: DEVPATH=/devices/pci0000:00/0000:00:1d.7/usb2/2-5/2-5:1.0/host2/target2:0:0/2:0:0:0/block/sdb
E: DEVTYPE=disk
E: ID_BUS=usb
E: ID_INSTANCE=0:0
E: ID_MODEL=DT_101_G2
E: ID_MODEL_ENC=DT\x20101\x20G2\x20\x20\x20\x20\x20\x20\x20
E: ID_MODEL_ID=1642
E: ID_PART_TABLE_TYPE=dos
E: ID_PATH=pci-0000:00:1d.7-usb-0:5:1.0-scsi-0:0:0:0
E: ID_PATH_TAG=pci-0000_00_1d_7-usb-0_5_1_0-scsi-0_0_0_0
E: ID_REVISION=PMAP
E: ID_SERIAL=Kingston_DT_101_G2_001CC0EC34A2BB318709004B-0:0
E: ID_SERIAL_SHORT=001CC0EC34A2BB318709004B
E: ID_TYPE=disk
E: ID_USB_DRIVER=usb-storage
E: ID_USB_INTERFACES=:080650:
E: ID_USB_INTERFACE_NUM=00
E: ID_VENDOR=Kingston
E: ID_VENDOR_ENC=Kingston
E: ID_VENDOR_ID=0951
E: MAJOR=8
E: MINOR=16
E: SUBSYSTEM=block
E: USEC_INITIALIZED=32380484

But when I wanted to test it, it gave me this log:

# udevadm test /devices/pci0000:00/0000:00:1d.7/usb2/2-5/2-5:1.0/host2/target2:0:0/2:0:0:0/block/sdb
calling: test
version 204
This program is for debugging only, it does not run any program
specified by a RUN key. It may show incorrect results, because
some values may be different, or not available at a simulation run.

=== trie on-disk ===
tool version:          204
file size:         5729797 bytes
header size             80 bytes
strings            1262125 bytes
nodes              4467592 bytes
load module index
Skipping overridden file: /lib/udev/rules.d/95-keymap.rules.
read rules file: /lib/udev/rules.d/42-usb-hid-pm.rules
read rules file: /lib/udev/rules.d/50-firmware.rules
read rules file: /lib/udev/rules.d/50-udev-default.rules
read rules file: /lib/udev/rules.d/55-dm.rules
read rules file: /lib/udev/rules.d/56-lvm.rules
read rules file: /lib/udev/rules.d/60-cdrom_id.rules
read rules file: /lib/udev/rules.d/60-fuse.rules
read rules file: /lib/udev/rules.d/60-gnupg.rules
read rules file: /lib/udev/rules.d/60-libfreenect0.2.rules
read rules file: /lib/udev/rules.d/60-libgphoto2-6.rules
read rules file: /lib/udev/rules.d/60-libpisock9.rules
read rules file: /lib/udev/rules.d/60-libsane.rules
read rules file: /lib/udev/rules.d/60-nvidia-kernel-common.rules
read rules file: /lib/udev/rules.d/60-pcmcia.rules
read rules file: /lib/udev/rules.d/60-persistent-alsa.rules
read rules file: /lib/udev/rules.d/60-persistent-input.rules
read rules file: /lib/udev/rules.d/60-persistent-serial.rules
read rules file: /lib/udev/rules.d/60-persistent-storage-dm.rules
read rules file: /lib/udev/rules.d/60-persistent-storage-tape.rules
read rules file: /lib/udev/rules.d/60-persistent-storage.rules
read rules file: /lib/udev/rules.d/60-persistent-v4l.rules
read rules file: /lib/udev/rules.d/60-virtualbox-dkms.rules
read rules file: /lib/udev/rules.d/60-virtualbox.rules
read rules file: /lib/udev/rules.d/61-accelerometer.rules
read rules file: /etc/udev/rules.d/61-removable-storage-polling.rules
read rules file: /lib/udev/rules.d/64-btrfs.rules
read rules file: /lib/udev/rules.d/64-xorg-xkb.rules
read rules file: /lib/udev/rules.d/69-cd-sensors.rules
IMPORT found builtin 'usb_id --export %p', replacing /lib/udev/rules.d/69-cd-sensors.rules:89
read rules file: /lib/udev/rules.d/69-libmtp.rules
read rules file: /lib/udev/rules.d/69-lvm-metad.rules
read rules file: /lib/udev/rules.d/69-xorg-vmmouse.rules
read rules file: /lib/udev/rules.d/70-btrfs.rules
read rules file: /etc/udev/rules.d/70-persistent-cd.rules
read rules file: /etc/udev/rules.d/70-persistent-net.rules
read rules file: /lib/udev/rules.d/70-power-switch.rules
read rules file: /lib/udev/rules.d/70-udev-acl.rules
read rules file: /etc/udev/rules.d/70-zram.rules
read rules file: /lib/udev/rules.d/75-cd-aliases-generator.rules
read rules file: /lib/udev/rules.d/75-net-description.rules
read rules file: /lib/udev/rules.d/75-persistent-net-generator.rules
read rules file: /lib/udev/rules.d/75-probe_mtd.rules
read rules file: /lib/udev/rules.d/75-tty-description.rules
read rules file: /lib/udev/rules.d/78-sound-card.rules
read rules file: /lib/udev/rules.d/80-btrfs-lvm.rules
read rules file: /lib/udev/rules.d/80-drivers.rules
read rules file: /lib/udev/rules.d/80-net-name-slot.rules
read rules file: /lib/udev/rules.d/80-networking.rules
read rules file: /lib/udev/rules.d/85-hdparm.rules
read rules file: /lib/udev/rules.d/85-hwclock.rules
read rules file: /lib/udev/rules.d/90-alsa-restore.rules
read rules file: /lib/udev/rules.d/90-pulseaudio.rules
read rules file: /lib/udev/rules.d/91-permissions.rules
read rules file: /lib/udev/rules.d/95-cd-devices.rules
read rules file: /lib/udev/rules.d/95-keyboard-force-release.rules
read rules file: /etc/udev/rules.d/95-keymap.rules
read rules file: /lib/udev/rules.d/95-udev-late.rules
read rules file: /lib/udev/rules.d/97-bluetooth-hid2hci.rules
read rules file: /etc/udev/rules.d/99-local.rules
rules contain 393216 bytes tokens (32768 * 12 bytes), 31233 bytes strings
27768 strings (226512 bytes), 24687 de-duplicated (198361 bytes), 3082 trie nodes used
IMPORT builtin 'usb_id' /lib/udev/rules.d/60-persistent-storage.rules:68
/sys/devices/pci0000:00/0000:00:1d.7/usb2/2-5/2-5:1.0: if_class 8 protocol 6
IMPORT builtin 'path_id' /lib/udev/rules.d/60-persistent-storage.rules:89
LINK 'disk/by-id/usb-Kingston_DT_101_G2_001CC0EC34A2BB318709004B-0:0' /lib/udev/rules.d/60-persistent-storage.rules:108
LINK 'disk/by-path/pci-0000:00:1d.7-usb-0:5:1.0-scsi-0:0:0:0' /lib/udev/rules.d/60-persistent-storage.rules:130
IMPORT '/sbin/blkid -o udev -p /dev/sdb' /lib/udev/rules.d/60-persistent-storage.rules:151
starting '/sbin/blkid -o udev -p /dev/sdb'
'/sbin/blkid -o udev -p /dev/sdb' [12103] exit with return code 0
RUN '/etc/init.d/hdparm hotplug' /lib/udev/rules.d/85-hdparm.rules:1
GROUP 6 /lib/udev/rules.d/91-permissions.rules:4
GROUP 25 /lib/udev/rules.d/91-permissions.rules:5
GROUP 25 /lib/udev/rules.d/91-permissions.rules:9
NAME="pendrak" ignored, kernel device nodes can not be renamed; please fix it in /etc/udev/rules.d/99-local.rules:1
LINK 'pen' /etc/udev/rules.d/99-local.rules:1
handling device node '/dev/sdb', devnum=b8:16, mode=0660, uid=0, gid=25
preserve permissions /dev/sdb, 060660, uid=0, gid=25
preserve already existing symlink '/dev/block/8:16' to '../sdb'
found 'b8:16' claiming '/run/udev/links/\x2fdisk\x2fby-id\x2fusb-Kingston_DT_101_G2_001CC0EC34A2BB318709004B-0:0'
creating link '/dev/disk/by-id/usb-Kingston_DT_101_G2_001CC0EC34A2BB318709004B-0:0' to '/dev/sdb'
preserve already existing symlink '/dev/disk/by-id/usb-Kingston_DT_101_G2_001CC0EC34A2BB318709004B-0:0' to '../../sdb'
found 'b8:16' claiming '/run/udev/links/\x2fdisk\x2fby-path\x2fpci-0000:00:1d.7-usb-0:5:1.0-scsi-0:0:0:0'
creating link '/dev/disk/by-path/pci-0000:00:1d.7-usb-0:5:1.0-scsi-0:0:0:0' to '/dev/sdb'
preserve already existing symlink '/dev/disk/by-path/pci-0000:00:1d.7-usb-0:5:1.0-scsi-0:0:0:0' to '../../sdb'
found 'b8:16' claiming '/run/udev/links/\x2fpen'
creating link '/dev/pen' to '/dev/sdb'
preserve already existing symlink '/dev/pen' to 'sdb'
.ID_FS_TYPE_NEW=
ACTION=add
DEVLINKS=/dev/disk/by-id/usb-Kingston_DT_101_G2_001CC0EC34A2BB318709004B-0:0 /dev/disk/by-path/pci-0000:00:1d.7-usb-0:5:1.0-scsi-0:0:0:0 /dev/pen
DEVNAME=/dev/sdb
DEVPATH=/devices/pci0000:00/0000:00:1d.7/usb2/2-5/2-5:1.0/host2/target2:0:0/2:0:0:0/block/sdb
DEVTYPE=disk
ID_BUS=usb
ID_FS_TYPE=
ID_INSTANCE=0:0
ID_MODEL=DT_101_G2
ID_MODEL_ENC=DT\x20101\x20G2\x20\x20\x20\x20\x20\x20\x20
ID_MODEL_ID=1642
ID_PART_TABLE_TYPE=dos
ID_PATH=pci-0000:00:1d.7-usb-0:5:1.0-scsi-0:0:0:0
ID_PATH_TAG=pci-0000_00_1d_7-usb-0_5_1_0-scsi-0_0_0_0
ID_REVISION=PMAP
ID_SERIAL=Kingston_DT_101_G2_001CC0EC34A2BB318709004B-0:0
ID_SERIAL_SHORT=001CC0EC34A2BB318709004B
ID_TYPE=disk
ID_USB_DRIVER=usb-storage
ID_USB_INTERFACES=:080650:
ID_USB_INTERFACE_NUM=00
ID_VENDOR=Kingston
ID_VENDOR_ENC=Kingston
ID_VENDOR_ID=0951
MAJOR=8
MINOR=16
SUBSYSTEM=block
USEC_INITIALIZED=32380484
run: '/etc/init.d/hdparm hotplug'
unload module index

And as you can see, the symlink is created, but the name hasn't changed, and I got the following error:

NAME="pendrak" ignored, kernel device nodes can not be renamed; please fix it in /etc/udev/rules.d/99-local.rules:1

The other thing is that the link points randomly to sdb, sdb1, sdb2, etc:

# ls -al /dev/pen
lrwxrwxrwx 1 root root 3 Mar 13 12:49 /dev/pen -> sdb
# ls -al /dev/pen
lrwxrwxrwx 1 root root 4 Mar 13 12:53 /dev/pen -> sdb2
# ls -al /dev/pen
lrwxrwxrwx 1 root root 4 Mar 13 12:53 /dev/pen -> sdb1
# ls -al /dev/pen
lrwxrwxrwx 1 root root 4 Mar 13 12:53 /dev/pen -> sdb2
# ls -al /dev/pen
lrwxrwxrwx 1 root root 4 Mar 13 12:53 /dev/pen -> sdb3

It changes every time I plug the pendrive in.

The task here is to change the name of the device from sdb (or whatever that would be) to pendrak and also create a link to it. The error claimed that "kernel device nodes can not be renamed" -- does it mean that I can't change the name at all, and all I can do is to create symlinks?

14

According to udev manual, there's no way to change the names of files in the /dev/ directory:

NAME
The name to use for a network interface. The name of a device node
cannot be changed by udev, only additional symlinks can be created.

So, in my case I should write rules similar to these:

KERNEL=="sd?3", ACTION=="add", ENV{ID_SERIAL_SHORT}=="001CC0EC34A2BB318709004B", \
    SYMLINK+="pen%n", \
    RUN+="/usr/bin/udevil mount /dev/pen%n /mnt/dane"

KERNEL=="sd?1", ACTION=="add", ENV{ID_SERIAL_SHORT}=="001CC0EC34A2BB318709004B", \
    SYMLINK+="pen%n", \
    RUN+="/usr/bin/udevil mount /dev/pen%n /mnt/debian"

KERNEL=="sd?2", ACTION=="add", ENV{ID_SERIAL_SHORT}=="001CC0EC34A2BB318709004B", \
    SYMLINK+="pen%n", \
    RUN+="/sbin/cryptsetup luksOpen /dev/pen%n pen%n --key-file=/home/morfik/Desktop/pen2.key", \
    RUN+="/usr/bin/udevil mount /dev/mapper/pen%n /mnt/szyfr"
KERNEL=="sd?2", ACTION=="remove", ENV{ID_SERIAL_SHORT}=="001CC0EC34A2BB318709004B", \
    RUN+="/sbin/cryptsetup luksClose pen%n"

They create three links: pen1, pen2, pen3. Each of which links to the corresponding sdb (or what ever that would be) device, and simply opens and mounts them in the specified directories via udevil tool.

  • What about wiki.archlinux.org/index.php/… – orion Mar 18 '14 at 20:29
  • 2
    This only applies to network interfaces, as you can read in the answer. – Mikhail Morfikov Mar 18 '14 at 23:16
  • 1
    Note: this used to work with other device types too, but this feature was removed with some systemd release. – ibre5041 Apr 6 '16 at 11:54
  • If we cannot rename kernel device nodes anymore, any workarounds? Any brute force ways? :D – midnite May 6 '16 at 17:24
  • Just create symlinks. I'm doing it for all devices that need to have the same names no matter what. – Mikhail Morfikov May 7 '16 at 7:15

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