</listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>TAGS</option></term>
+ <listitem>
+ <para>Search the devpath upwards for a device with matching tag.</para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><option>ENV{<replaceable>key</replaceable>}</option></term>
<listitem>
devices claim the same name, the link always points to the device with
the highest link_priority. If the current device goes away, the links are
re-evaluated and the device with the next highest link_priority becomes the owner of
- the link. If no link_priority is specified, the order of the devices, and
- which one of them owns the link, is undefined. Claiming the same name for
- a symlink, which is or might be used for a device node, may result in
- unexpected behavior and is not supported.
+ the link. If no link_priority is specified, the order of the devices (and
+ which one of them owns the link) is undefined. Also, symlink names must
+ never conflict with the kernel's default device node names, as that would
+ result in unpredictable behavior.
</para>
</listitem>
</varlistentry>
<term><option>ENV{<replaceable>key</replaceable>}</option></term>
<listitem>
<para>Set a device property value. Property names with a leading '.'
- are not stored in the database or exported to external tool or events.</para>
+ are neither stored in the database nor exported to events or
+ external tools (run by, say, the PROGRAM match key).</para>
</listitem>
</varlistentry>
this or a dependent device. Long running tasks need to be immediately
detached from the event process itself.</para>
<para>If no absolute path is given, the program is expected to live in
- <filename>/lib/udev</filename>, otherwise the absolute path must be
- specified. Program name and arguments are separated by spaces. Single quotes
- can be used to specify arguments with spaces.</para>
+ the directory provided at compile-time to configure via --libexecdir
+ (this is usually <filename>/lib/udev</filename>), otherwise the absolute
+ path must be specified. The program name and following arguments are
+ separated by spaces. Single quotes can be used to specify arguments with
+ spaces.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>LABEL</option></term>
<listitem>
- <para>Named label where a GOTO can jump to.</para>
+ <para>A named label to which a GOTO may jump.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>GOTO</option></term>
<listitem>
- <para>Jumps to the next LABEL with a matching name</para>
+ <para>Jumps to the next LABEL with a matching name.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>file</option></term>
<listitem>
- <para>Import a text file specified as the assigned value, which must be in
- environment key format.</para>
+ <para>Import a text file specified as the assigned value, the content
+ of which must be in environment key format.</para>
</listitem>
</varlistentry>
<varlistentry>
<varlistentry>
<term><option>cmdline</option></term>
<listitem>
- <para>Import a single property from the kernel commandline. For simple flags
+ <para>Import a single property from the kernel command line. For simple flags
the value of the property is set to '1'.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>WAIT_FOR</option></term>
<listitem>
- <para>Wait for a file to become available or until a 10
- seconds timeout expires. The path is relative to the sysfs device,
- i. e. if no path is specified this waits for an attribute to appear.</para>
+ <para>Wait for a file to become available or until a timeout of
+ 10 seconds expires. The path is relative to the sysfs device;
+ if no path is specified, this waits for an attribute to appear.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>static_node=</option></term>
<listitem>
- <para>Apply the permissions specified in this rule to a static device node with
+ <para>Apply the permissions specified in this rule to the static device node with
the specified name. Static device nodes might be provided by kernel modules
or copied from <filename>/lib/udev/devices</filename>. These nodes might not have
a corresponding kernel device at the time udevd is started; they can trigger
<varlistentry>
<term><option>watch</option></term>
<listitem>
- <para>Watch the device node with inotify; when closed after being opened for
- writing, a change uevent is synthesised.</para>
+ <para>Watch the device node with inotify; when the node is closed after being opened for
+ writing, a change uevent is synthesized.</para>
</listitem>
</varlistentry>
<varlistentry>
<para>The <option>NAME</option>, <option>SYMLINK</option>, <option>PROGRAM</option>,
<option>OWNER</option>, <option>GROUP</option>, <option>MODE</option> and <option>RUN</option>
- fields support simple printf-like string substitutions. The <option>RUN</option>
- format chars gets applied after all rules have been processed, right before the program
- is executed. It allows the use of device properties set by earlier matching
- rules. For all other fields, substitutions are applied while the individual rule is
+ fields support simple string substitutions. The <option>RUN</option>
+ substitutions are performed after all rules have been processed, right before the program
+ is executed, allowing for the use of device properties set by earlier matching
+ rules. For all other fields, substitutions are performed while the individual rule is
being processed. The available substitutions are:</para>
<variablelist>
<varlistentry>
<para>The value of a sysfs attribute found at the device where
all keys of the rule have matched. If the matching device does not have
such an attribute, and a previous KERNELS, SUBSYSTEMS, DRIVERS, or
- ATTRS test selected a parent device, use the attribute from that
- parent device.
- If the attribute is a symlink, the last element of the symlink target is
+ ATTRS test selected a parent device, then the attribute from that
+ parent device is used.</para>
+ <para>If the attribute is a symlink, the last element of the symlink target is
returned as the value.</para>
</listitem>
</varlistentry>
<term><option>$result</option>, <option>%c</option></term>
<listitem>
<para>The string returned by the external program requested with PROGRAM.
- A single part of the string, separated by a space character may be selected
+ A single part of the string, separated by a space character, may be selected
by specifying the part number as an attribute: <option>%c{N}</option>.
- If the number is followed by the '+' char this part plus all remaining parts
+ If the number is followed by the '+' character, this part plus all remaining parts
of the result string are substituted: <option>%c{N+}</option></para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>$links</option></term>
<listitem>
- <para>The current list of symlinks, separated by a space character. The value is
- only set if an earlier rule assigned a value, or during a remove events.</para>
+ <para>A space-separated list of the current symlinks. The value is
+ only set during a remove event or if an earlier rule assigned a value.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>$tempnode</option>, <option>%N</option></term>
<listitem>
- <para>The name of a created temporary device node to provide access to
+ <para>The name of a temporary device node created to provide access to
the device from a external program before the real node is created.</para>
</listitem>
</varlistentry>
~ianmdlvl / elogind.git / blobdiff