HAL-0.5.9.1

The default setup for HAL is to allow only certain users to invoke methods such as Mount(). These are the root user and the user determined to be at the active console using pam_console. If you are not set up to use Linux-PAM-0.99.10.0 and pam_console, create a group that is allowed to invoke HAL methods with the following commands:

groupadd -g 61 halusers &&
cat > /etc/dbus-1/system.d/halusers.conf << "EOF"
<!DOCTYPE busconfig PUBLIC
 "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>

 <!-- Allow users in the halusers group invoke HAL methods -->
 <policy group="halusers">
  <allow send_interface="org.freedesktop.Hal.Device.SystemPowerManagement"/>
  <allow send_interface="org.freedesktop.Hal.Device.LaptopPanel"/>
  <allow send_interface="org.freedesktop.Hal.Device.Volume"/>
  <allow send_interface="org.freedesktop.Hal.Device.Volume.Crypto"/>
 </policy>

</busconfig>
EOF

Now add the users you would like to the halusers group to use HAL.

usermod -a -G halusers <username>

Note that these users still need to have appropriate permissions to access the devices that HAL will invoke its methods on.

With the above configuration in place, authorized users now have the ability to unmount disk partitions mounted at non-standard locations such as /pub. If you'd like to restrict this policy to only drives which are considered removable or hotpluggable, add the following configuration file as the root user:

cat > /etc/hal/fdi/policy/no-fixed-drives.fdi << "EOF"
<?xml version="1.0" encoding="UTF-8"?> <!-- -*- SGML -*- -->

<!-- Don't allow HAL methods on disks that are not
     removable or hotpluggable -->

<deviceinfo version="0.2">
<device>
  <match key="@block.storage_device:storage.hotpluggable" bool="false">
    <match key="@block.storage_device:storage.removable" bool="false">
      <merge key="volume.ignore" type="bool">true</merge>
    </match>
  </match>
</device>
</deviceinfo>
EOF

HAL only provides the methods such as Mount() to act on hardware. In order to take advantage of these, a HAL event handler such as gnome-volume-manager-2.17.0 or Ivman should be installed.

In some cases, it is necessary to specify some default mount options for filesystems. E.g., in non-English environments, the iocharset and codepage options are needed for filesystems of Windows origin in order to show national characters correctly. Also, due to a bug in the Linux kernel version in LFS (2.6.22.x), you may want to pass the usefree option to vfat filesystems in order to reduce the time needed to determine the amount of free space on the filesystem.

Google search results for “hal default mount options” are still full of recommendations to create *.fdi files mentioning either volume.policy or storage.policy keys. Such recommendations worked for HAL-0.4.x only and are invalid now. For HAL-0.5.9.1, mount options are expected to be handled as follows:

The important point above is that the configuration procedure is desktop-specific. However, as of December, 2007, only GNOME allows the user to set default mount options on a per-filesystem basis, as described in the next paragraph. KDE allows the mount options to be set only on a per-volume basis, not per-filesystem, which is a bug, because, as mentioned in the report, “for every new device (let's say your friend's USB stick) you have to first not mount it, then change options and then mount”. Xfce, if compiled with HAL support, hard-codes the mount options without any means to override them, which is even worse. In KDE and Xfce, if the built-in default mount options are not suitable, it is needed to mention every possible removable storage device in /etc/fstab with the correct options, thus mostly defeating the point of installing HAL.

In order to adjust the default mount options, GNOME users should change the /system/storage/default_options/[fs_type]/mount_options GConf key either using GConf Editor-2.18.0, or from the command line, as demonstrated in the following example:

gconftool-2 --type list --list-type=string \
    --set /system/storage/default_options/vfat/mount_options \
    "[shortname=mixed,uid=,usefree,iocharset=koi8-r,codepage=866]"

See more details in the gnome-mount(1) manual page.

The list of mount options permitted in the default HAL configuration resides in the /usr/share/hal/fdi/policy/10osvendor/20-storage-methods.fdi file. GNOME and KDE users may want to use options not in this list (in the above example, this applies to the usefree option). In this case, as root user, create a custom policy file that mentions unknown mount options:

cat > /etc/hal/fdi/policy/user-options.fdi << "EOF"
<?xml version="1.0" encoding="UTF-8"?> <!-- -*- SGML -*- -->

<!--
This file is used to set custom options to the HAL policy settings.
The default policy settings are defined in files contained in the
/usr/share/hal/fdi/policy subdirectories. User defined customizations
should be in files contained in the /etc/hal/fdi/policy directory.
-->

<deviceinfo version="0.2">
<device>

<!-- this is to be able to mount media in drives we cannot poll,
     e.g. IDE Zip Drives and PC style floppy drives -->
<match key="storage.media_check_enabled" bool="false">
  <match key="storage.no_partitions_hint" bool="true">
    <append key="volume.mount.valid_options" type="strlist">usefree</append>
    <!-- Insert other options here -->
  </match>
</match>

<match key="volume.fsusage" string="filesystem">

  <!-- allow these mount options for vfat -->
  <match key="volume.fstype" string="vfat">
    <append key="volume.mount.valid_options" type="strlist">usefree</append>
    <!-- Insert other options here -->
  </match>
</match>

</device>
</deviceinfo>
EOF