Udev - Run Program on Usb Flash Drive Insert

UDEV - Run program on USB flash drive insert

First you need your rule to detect usb storage devices

/etc/udev/rules.d/10-usbmount.rules:

KERNEL=="sd*[!0-9]|sr*", ENV{ID_SERIAL}!="?*", SUBSYSTEMS=="usb", RUN+="/usr/bin/usbdevinserted"

This runs our custom executable shell script /usr/bin/usbdevinserted:

#!/bin/bash

set 2>&1 >> /tmp/usbdevinfo

This sample script dumps the environment variables which you will need to know which device was found, eg:

DEVLINKS='/dev/disk/by-id/usb-Generic_USB_Flash_Disk-0:0 /dev/disk/by-path/pci-0000:00:13.2-usb-0:2:1.0-scsi-0:0:0:0'
DEVNAME=/dev/sdk
DEVPATH=/devices/pci0000:00/0000:00:13.2/usb2/2-2/2-2:1.0/host29/target29:0:0/29:0:0:0/block/sdk
DEVTYPE=disk
ID_BUS=usb
ID_FS_TYPE=
ID_INSTANCE=0:0
ID_MODEL=USB_Flash_Disk
ID_MODEL_ENC='USB\x20Flash\x20Disk\x20\x20'
ID_MODEL_ID=9380
ID_PART_TABLE_TYPE=dos
ID_PART_TABLE_UUID=61d1df0b
ID_PATH=pci-0000:00:13.2-usb-0:2:1.0-scsi-0:0:0:0
ID_PATH_TAG=pci-0000_00_13_2-usb-0_2_1_0-scsi-0_0_0_0
ID_REVISION=7.76
ID_SERIAL=Generic_USB_Flash_Disk-0:0
ID_TYPE=disk
ID_USB_DRIVER=usb-storage
ID_USB_INTERFACES=:080650:
ID_USB_INTERFACE_NUM=00
ID_VENDOR=Generic
ID_VENDOR_ENC='Generic\x20'
ID_VENDOR_ID=058f
MAJOR=8
MINOR=160
SUBSYSTEM=block

Ubuntu run script as user when usb inserted

Indeed, as MiiinimalLogic suggested, the problem was owner of the script.
If you want to run a script as another user via su, the script should belong to root.

The file may still reside in user's home.

Run script with udev after USB plugged in on RPi

Well you probably described you problem. The mount process is too slow. You can mount your usb device from your script.sh

Also you probably need to disable automatic USB device mount for your system or the specific device only.

If you add a symlink to your udev rule e.g. SYMLINK+="backup", then you can mount this device by:

mkdir -p /path/to/foo
mount -t ext4 /dev/backup /path/to/foo

Auto mount usb drive from udev rules and shell script

I think I identified the problem.
Apparently, udev uses a specific namespace, indeed I can see the mount point by printing the content of /proc/<daemon_pid>/mountinfo where is the pid of the systemd-udevd service.

$ cat /proc/240/mountinfo
[...]
228 43 8:17 / /media/usb/test rw,relatime - vfat /dev/sdb1 rw,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro

$ df
Sys. de fichiers blocs de 1K  Utilisé Disponible Uti% Monté sur
udev                 1975740        0    1975740   0% /dev
tmpfs                 397376     5916     391460   2% /run
/dev/sda2           75733088 69473400    2389532  97% /
tmpfs                1986868   111860    1875008   6% /dev/shm
tmpfs                   5120        4       5116   1% /run/lock
tmpfs                1986868        0    1986868   0% /sys/fs/cgroup
tmpfs                 397372       28     397344   1% /run/user/112
tmpfs                 397372       24     397348   1% /run/user/1001

So the solution should be to force udev to execute the script in root userspace.
I tried the solution I found here https://unix.stackexchange.com/questions/330094/udev-rule-to-mount-disk-does-not-work

However, my system doesn't have a /usr/lib/systemd/system/systemd-udevd.service file. I created a file /etc/systemd/system/systemd-udevd.service with content

MountFlags=shared 

But with this solution, my system is not able to boot anymore.

Does someone know how I could either execute the script in root userspace or share the mount point with users?

PS : I precise I'm running a 64 bits Debian 9

Solved edit : Finally the file was located at /lib/systemd/system/systemd-udevd.service. I duplicated it in /etc/systemd/system/systemd-udevd.service
and changed MountFlags=slave to MountFlags=shared and now it works perfectly :)

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