--- name: "ledcontrol.conf" section: "5" platform: "linux" package: "ledcontrol" version: "0.5.2-11.1" release: "Debian 6.0 (Squeeze)" platforms: ["linux"] url: "https://new.carta.tech/ledcontrol.conf" --- # ledcontrol.conf(5) configuration file for ledd's default startup script ## NAME ledcontrol.conf - configuration file for **ledd**'s default startup script ## DESCRIPTION The file **ledcontrol.conf** is the configuration file for [**startup.sh**(8)](/startup.sh/8.md), the default startup script for [**ledd**(8)](/ledd/8.md), part of the ledcontrol package. **ledcontrol.conf** configures under what circumstances what LEDs are lighted. It is parsed by *startup.sh* as a shell script, so blank lines and lines with a number sign (\`\`#'') are ignored. It can therefore also include normal shell commands for more complex actions. Everything written to standard output is parsed by **ledd** as commands and everything written to standard error is logged via the chosen logging mechanism on a warning level. The default file is pretty well commented, so you should be able to configure it just by looking at it. The configuration itself is done by setting environment variables. The format is \`\`VARIABLE="option"''. All options should be set. ## GENERAL CONFIGURATION PARAMETERS - **STARTUP\_ANIM=**\[YES\|NO\] If set to YES, a short animation (about 1 second) is flashed when starting **ledd**. It is ignored if started in X, as this might leave the LEDs in an incorrect state. It is done in the background, so it doesn't slow the booting. - **USE\_BACKGROUNDING=**\[YES\|NO\] If set to YES, then some slow tests (eg. pinging a remote host that isn't responding) are done in the background so as not to delay other checks. This is automatically disabled if using bash 2.x.x as it has a bug that makes it freeze. It is safe to leave this on. - **MINIMUM\_DELAY=***VALUE* Sleep *VALUE* seconds at minimum between the checks. This gives the resolution of the check timings (a scheduled check can be delayed at most *VALUE* seconds). 5 is a reasonable value. Note that you will probably get a disk-access every *VALUE* seconds (see [**startup.sh**(8)](/startup.sh/8.md) section **SILENCING** for details). - **DEFAULT\_SETTINGS=**"command" These settings are set at the beginning. (See [**ledd**(8)](/ledd/8.md) section **COMMANDS**) ## TEST CONFIGURATION PARAMETERS The different tests are defined by four variables per test. Each one is suffixed with an underscore and a number. The numbers have to rise from 1 up (you're not allowed to skip numbers). The variables are as follow: - **COMMAND\_***nn* Command to test the condition. This can be any command available on the system or a build-it check (see **BUILT-IN CHECKS** below). It should not print anything to stdout (except in special conditions, see **WRITING SCRIPTS** below). Errors may be printed to stderr. - **SUCCESS\_***nn* Command to give **ledd** if **COMMAND\_***nn* returns successfully (exit code 0). If an arbitrary number is to be indicated (using commands "frequency" or "dutycycle", see [**ledd**(8)](/ledd/8.md)), the last argument (the value) should be omitted. - **FAILURE\_***nn* Command to give **ledd** if **COMMAND\_***nn* returns unsuccessfully (exit code non-zero). If an arbitrary value is to be indicated this variable may be ignored, but must be present (eg. "nop"). - **DELAY\_***nn* Minimum time between tests. The resolution of this is determined by **MINIMUM\_DELAY**. ## BUILT-IN CHECKS Ledcontrol offers certain common checks built-in. The command names are prefixed with **led\_**. They can be used in the checks as any other commands. The following checks are boolean checks. - **led\_ppp** Check for a PPP-link. Returns true if a network interface with the name ppp0 to ppp9 is found. - **led\_ping** *host* Returns true if *host* replies to a ping packet. [**ping**(8)](/ping/8.md) must be available on the machine. This function uses backgrounding, if available. - **led\_file** *file(s)* ... Returns true if every one of *file(s)* exist. *file(s)* may contain wildcards (in that case at least one file has to match each pattern). - **led\_size** *file* *min* \[*max*\] Returns true if *file* exists and its size is greater or equal to *min* and (optionally) less than *max*. This can be used to detect mail in someone's mailbox. The following checks set the LED to indicate a number. The **SUCCESS\_***nn* command should be either type "set xxx frequency" or "set xxx dutycycle", where the last argument (the value) is omitted. - **led\_load** Indicate the current system load (1 minute average). **FAILURE\_***nn* is ignored, but must be present. - **led\_netload** *iface* *type* Indicate current network load on interface *iface*. *type* may be "IN", "OUT", or "BOTH" for inbound traffic, outbound traffic or both together. The value is given as kB/s (kilobytes per second). The longer **DELAY\_***nn* is, the more accurate the value. Returns false if no such interface exists. ## WRITING SCRIPTS If you want to use the scriptability to the full extent, I suggest you write custom "built-in" functions. This can be done either by adding it to /usr/share/ledcontrol in a file ending in **.sh** (it doesn't have to be executable) or by writing it in **ledcontrol.conf**. In both cases it is sourced by *startup.sh* at startup. Read the existing scripts for examples. ## Environment variables in functions The following environment variables are available to the function: - **LEDDSCRIPTS** Directory in which all the scripts should be located, including *startup.sh*. - **SUCCESS** The command to be given on successful exit value. The function may change this to give another command (it is restored between calls). - **FAILURE** The command to be given on unsuccessful exit values. The function may change this to give another command. - **COMMAND** The whole command that was executed to start the function. Note that command line arguments are also available in $1, $2, etc. - **COUNT** Number part of **COMMAND\_***nn*. Can be used to store variables between calls (see **Storing variables between calls** below). This must not be changed! - **USE\_BACKGROUNDING** Set to YES if slow checks should be backgrounded (see **Backgrounding** below). ## Arbitrary number indication If you want to make a script that outputs an arbitrary number, you should append the number to the environment variable SUCCESS and return 0 (for example load.sh, netload.sh). ## Storing variables between calls The function may use almost any variables internally, but must not depend on them staying same between calls, as there might be several tests using the function. Instead you can use variables beginning with the function name and with $COUNT appended to it. This can be done as follows (other means exist in new versions of **bash**): ``` # Read previously saved value to $LOCAL eval 'LOCAL=LED_NAME_DESC_'$COUNT # Store value from $LOCAL for future use eval 'LED_NAME_DESC_'$COUNT'=$LOCAL' ``` ## Backgrounding Tests which may take many seconds to complete (eg. ping when remote host is not responding) should check whether the variable **USE\_BACKGROUNDING** is set to "YES" and in that case make the test in a background process. The function itself should set **SUCCESS** to "nop" and return successfully and the subprocess check the condition and echo $SUCCESS or $FAILURE depending on the result. Note that when making the background process, you should **always** check whether the old process is still running. The background process can be made by ``` # Retrieve old PID if test -z "$PID" -o ! -e "/proc/$PID" ; then ( commands ) & PID=$! fi # Store PID ``` ## Examples of scripts Look at the existing scripts. For basic boolean checks, see eg. *file.sh*, *size.sh* and *ppp.sh*. For examples of arbitrary number indication, see *load.sh*, or a more complex example with variable storing in *netload.sh*. For an example of backgrounding, see *ping.sh*. ## EXAMPLE Example configuration file: ``` # Give startup animation STARTUP_ANIM=YES # Use backgrounding (automatically disabled if dangerous) USE_BACKGROUNDING=YES # Minimum delay of 5 seconds is reasonable MINIMUM_DELAY=5 # We use Caps Lock and Scroll Lock, so set them off. DEFAULT_SETTINGS="set c1s1 off" # Two tests: # Scroll Lock indicates the current system load # Caps Lock is lighted when a ppp-link is up and blinks when # "somehost.example" responds. COMMAND_1="led_load" SUCCESS_1="set s5 frequency 0.8 1000 1.9 100" FAILURE_1="nop" # Ignored, but must be present. DELAY_1=10 # Not so critical check. COMMAND_2="led_ppp" SUCCESS_2="set c4 on" FAILURE_2="set c4c6 normal" # We assume that if this fails, # ping will also fail. DELAY_2=5 # For immediate response COMMAND_3="led_ping somehost.example" SUCCESS_3="set c6 blink 500" FAILURE_3="set c6 normal" DELAY_3=20 # Not so critical check. ``` ## FILES - */etc/ledcontrol.conf* default configuration file location - */usr/share/ledcontrol/* location of the default startup script *startup.sh* and other scripts ## SEE ALSO [**startup.sh**(8)](/startup.sh/8.md), [**ledd**(8)](/ledd/8.md), [**ledd.conf**(5)](/ledd.conf/5.md), [**ledcontrol**(1)](/ledcontrol/1.md), [**bash**(1)](/bash/1.md), [**ping**(8)](/ping/8.md) ## AUTHOR Ledcontrol was written by Sampo Niskanen \. You can get the latest version of ledcontrol from *http://www.iki.fi/sampo.niskanen/ledcontrol/* ## BUGS **bash** version 2.xx.xx has a bug in it that causes *startup.sh* to lock up if backgrounding is used. From version 0.5.0 up this has been checked by *startup.sh* and if a bad version of **bash** is being used the variable **USE\_BACKGROUNDING** is automatically set to "NO". The default startup script may cause a disk-access every **MINIMUN\_DELAY** seconds. See [**startup.sh**(8)](/startup.sh/8.md) for more info.