I want to use dbus-send to send a method to umount the usb volume.
However,the error is shown below:

dbus-send --system --print-reply --dest=org.freedesktop.Hal /org/freedesktop/Hal/devices/volume_uuid_4409_6AFB org.freedesktop.Hal.Device.Volume.Unmount
Error org.freedesktop.DBus.Error.UnknownMethod: Method "UnMount" with signature "" on interface "org.freedesktop.Hal.Device.Volume" doesn't exist

I use "lshal" to see the hal info:
udi = '/org/freedesktop/Hal/devices/volume_uuid_4409_6AFB'
volume.unmount.valid_options = {'lazy'} (string list)
volume.mount.valid_options = {'ro', 'sync', 'dirsync', 'noatime', 'nodiratime', 'noexec', 'quiet', 'remount', 'exec', 'utf8', 'sho
rtname=', 'codepage=', 'iocharset=', 'umask=', 'dmask=', 'fmask=', 'uid='} (string list)
org.freedesktop.Hal.Device.Volume.method_execpaths = {'hal-storage-mount', 'hal-storage-unmount', 'hal-storage-eject'} (string lis
t)
org.freedesktop.Hal.Device.Volume.method_argnames = {'mount_point fstype extra_options', 'extra_options', 'extra_options'} (string
list)
org.freedesktop.Hal.Device.Volume.method_signatures = {'ssas', 'as', 'as'} (string list)
org.freedesktop.Hal.Device.Volume.method_names = {'Mount', 'Unmount', 'Eject'} (string list)
info.interfaces = {'org.freedesktop.Hal.Device.Volume'} (string list)
volume.ignore = false (bool)
info.udi = '/org/freedesktop/Hal/devices/volume_uuid_4409_6AFB' (string)
..........


As you can see,the Unmount method is right there.
How can I solve it?
Thanks!

Check if you have the halmount command. It does what you are trying to do. If you have it but you don't want to use it, you can at least read it because it is a python script. ( on my system at least )

Which package does the "halmount" belong to ?
I use debian 4.0 and use apt-cache search halmount, got nothing matched.
Thanks!

It is a part of ivman. Ike's volume manager.

I just had a thought. Make sure that you don't have the "noacpi" kernel boot option. This will prevent the dbus and hal daemons from running.

I have installed the ivman,but there is no "halmount".
Is the ivman the right package in your distribution?
Could you tell me the details in halmount?
Thanks!

I use an rpm based system. rpm -qi ivman shows this url:
URL : http://ivman.sourceforge.net/

I downloaded the ivman source myself and I guess that the halmount is a wrapper around the commands supplied by ivman. It may be suse specific.

ftp://ftp.pbone.net/mirror/ftp.opens....14-72.src.rpm
If you download the SuSE rpm package, you can use "mc" to extract the halmount.py script. The /usr/bin/halmount command is simply a symbolic link to /usr/bin/halmount.py.

The rest of the source package is a tarball of the ivman package. There should be plenty there to study. Maybe you will write your own wrapper for the ivman commands to do what you want, or simply craft the xml rules.

--
You can also use:
rpm2cpio ivman-0.6.14-72.src.rpm >ivman-0.6.14-72.cpio
cpio -vid < ivman-0.6.14-72.cpio
to extract the files from the rpm.

---

There is also a halmount.1 man page. However, be sure to study the script before using it. The xml files used by ivman or hal may differ between my setup and yours. HAL works hand in hand with udevinfo when a device is added. Your system may be configured differently. This script uses the label of a filesystem, and udev creates a /dev/disk/by-label/<label> symbolic shortcut to the actual device. The rules for it to do this are in /etc/udev/rules.d/. Your system may not do this as its configured.

Another thing to look at is your system uses the PolicyKit package which may control whether a regular user using a desktop manager can mount a device. The policy kit distinguishes between a user using the desktop or one ssh'ing into the computer and may allow or deny an action accordingly. ( some documentation in /usr/share/doc/policykit/spec/polkit-spec.html if it's installed )

I know this is a lot to digest. I wish there was better documentation on dbus, hal, udev & policy kit and how it all fits together.

Thanks very much!
I will dig it!