automounting USB Flash Drive

I'm wondering if anyone has tackled the issue of having a USB flash drive automatically mount to the file system when it is inserted? I am working on a TI DM355 DaVinci EVM board running MontaVista Linux 4.0.1.

I can do this manually easily enough by:

mkdir /mnt/usbflash
mount /dev/sda1 /mnt/usbflash

To make this mount occur automatically, I *think* that I need to use autofs to do this, but if that's wrong I'd like to know.

Using autofs, here is what I did...

I inserted the following into /etc/auto.master:
/mnt/usbflash /etc/auto.usbflash --timeout=30 --ghost

I inserted the following into /etc/auto.usbflash:
usbflash -fstype=auto,sync :/dev/sda1

I then:
mkdir /mnt/usbflash
/etc/init.d/autofs restart

and this appeared to work. But for some reason, the directory /mnt/usbflash was mysteriously deleted. And inserting the USB stick does not force an automatic mount.

Any suggestions?
Thanks in advance.

You might want to explore udev as well...

I am not sure about MontaVista, but normally all these stuff is in /etc/fstabs.

What is kernel version of MontaVista Linux 4.0.1?

The kernel version is 2.6.10.

im not sure if this is elegant but you can waste negligible processor cycles by doing something like:
[untested]

while [ 1 ]
do
 mnt=`dmesg | tail | grep usb` # my system spits out the make/ model of the usb thumb drive when i insert it
 if [ mnt ]
 then
  mount /mnt/point /dir
 fi
done

[/untested]

Check this page out about writing udev rules.

http://reactivated.net/writing_udev_rules.html

You can download a program called automount and this program will automatically mount a usb flsh drive for you without any edit of /etc/fstab or script.

Originally Posted by Peter_APIIT You can download a program called automount and this program will automatically mount a usb flsh drive for you without any edit of /etc/fstab or script.

this seems like the least abrasive solution. i've never looked at the source for automount but i suspect that it does the equivelent of :

while [ 1 ]
do
 mnt=`dmesg | tail | grep usb` # my system spits out the make/ model of the usb thumb drive when i insert it
 if [ mnt ]
 then
  mount /mnt/point /dir
 fi
done

If you have udev, you could use something like this:

KERNEL=="sd[a-z]", NAME="%k", SYMLINK+="usb%m", GROUP="users", OPTIONS="last_rule"
ACTION=="add", KERNEL=="sd[a-z][0-9]", SYMLINK+="usb%n", GROUP="users", NAME="%k"
ACTION=="add", KERNEL=="sd[a-z][0-9]", RUN+="/bin/mkdir -p /mnt/usb%n"
ACTION=="add", KERNEL=="sd[a-z][0-9]", PROGRAM=="/lib/udev/vol_id -t %N", RESULT=="vfat", RUN+="/bin/mount -t vfat -o rw,noauto,flush,quiet,nodev,nosuid,noexec,noatime,dmask=000,fmask=111 /dev/%k /mnt/usb%n", OPTIONS="last_rule"
ACTION=="add", KERNEL=="sd[a-z][0-9]", RUN+="/bin/mount -t auto -o rw,noauto,sync,dirsync,noexec,nodev,noatime /dev/%k /mnt/usb%n", OPTIONS="last_rule"
ACTION=="remove", KERNEL=="sd[a-z][0-9]", RUN+="/bin/umount -l /mnt/usb%n"
ACTION=="remove", KERNEL=="sd[a-z][0-9]", RUN+="/bin/rmdir /mnt/usb%n", OPTIONS="last_rule"

It will probably need tweaking to work with your specific setup, this is my setup and it works very well.

Depends on your version of Montavista but 5.0 has udev support and as people have contributed above this is the best way.