Syntax

The detect.conf file specifies the tests that allow whereami to figure out where it is. The environment of such tests can be manipulated using the 'set' command. Tests can be performed conditionally upon the results of other tests using "if ... fi" constructs.

Comments are lines starting with the `#' character. Leading whitespace is ignored on all lines, including comment lines.

Internal Commands

The syntax of this file is fairly straightforward. Tests are specified thus:

testname parameter locations

The command testname is run with the single parameter (which may be split internally). If the return value is 0, the test is considered `successful' and the locations are considered `discovered'.

locations is a list of comma separated identifiers, each one matching the regexp ``[[:alnum:]._-]+''.

On success, processing will skip all non-`always' statements up to the next `if' or `fi' keyword, whichever is earlier.

if location statements ... [elif location statements ...]... [else statements ...] fi

If the location is in the list of locations discovered so far, then the statements in the `if' branch will be processed. Otherwise, if present, the statements in either the `elif' or the `else' (as appropriate) branch will be processed.

Note that nesting of `if' blocks is not supported at this time.

always testname parameter locations

A test preceded by the word `always' is not skipped unless it is within the inactive branch of an `if' clause.

set variable value

The environment variable is defined as value for all subsequent test scripts and in the shell script eventually constructed by whereami.

at locations

The locations will be added to the "discovered" list.

notat locations

The locations will be removed from the "discovered" list.

echo quoted text string

The "quoted text string" will be displayed to the user on stdout.

The parameter and locations may be lists, with a comma (",") used to separate multiple values.

Tests

Any program may be used as a test so long as it accepts a single parameter and returns zero on success and non-zero on failure.

If a parameter of the test script must contain a space, it parameter will need to be quoted.

A number of tests are included in the whereami package.

testdhcp [interface,]pattern

Tests for the assignment by DHCP of an IP address matching the specified address pattern. If not specified, the interface defaults to `eth0'.

Note that the first execution of this test during a particular run of whereami induces a DHCP request on the specified interface.

testmii interface

Checks for the presence of a link on interface using the mii-tool utility. If a link is not found then the interface will be 'down'ed to limit side-effects on other detection later.

testpppoe interface

Tries to start a PPPoE connection on the specified interface. Success is returned if the connection starts.

testarp interface,mac_address,ip_address

Performs an arping (Debian package: iputils-arping) to look for the specified mac_address and ip_address combination on the network connected to interface.

testping [interface,]ip_to_ping,ip_to_use

Uses the fping program to perform a fast ping to look for the presence of a particular host on the local network.

testpci pattern

Searches for the pattern in the output of lspci -v.

This enables checking for specific hardware, such as a particular type of docking station.

testmodule pattern

Searches for the pattern in the output of lsmod.

This is useful for checking for the presence of a particular PCMCIA card, or possibly a particular kernel configuration.

testap [interface,]scan

testap pattern[,WEP Key]

testap [interface,]pattern,WEP Key

The pattern is a regexp (egrep regexp) used to match AP essids: when this regexp matches a detected essid the test is considered succesfull.

This check does not require encryption to be set up to work, although it may not find stealthier equipment - use testssid in that case.

The 'scan' option will cause a new scan, and the first call should have this option set. Subsequent calls will use the results of that first scan, reducing the overhead for those busy people who connect to many WLANs!

If a WEP key is supplied, and a pattern match is found, the key will be assigned to that interface so that subsequent tests should work correctly.

When using the WEP key you may in some cases desire to pass additional parameters to iwconfig. These parameters may be passed preceding the WEP key and separated with an underscore. For example "restricted_0123-4567-89" will force the card to be configured to insist on 'restricted' mode at the same time as the key was set.

testappassive [interface,]scan

testappassive pattern

testap [interface,]pattern

Checks whether the specified AP is present, passively. This check does not alter the essid on the interface, or set the WEP key like the testap test. It just uses iwlist interface scan. This is useful where you have another external script that sets up all the wifi settings, and running whereami a second time destroys the running wifi connection, as can happen on boot where networking is intialised before whereami starting in run level 2.

The 'scan' option will cause a new scan, and the first call should have this option set. Subsequent calls will use the results of that first scan, reducing the overhead for those busy people who connect to many WLANs!

testprocsys proc-or-sys-path,egrep-pattern

Checks the specified /sys or /proc file to see if it contains the given egrep expression. Non-existent file results in failure, as well as a failed match. Useful for those interfaces that require to hotplug to be configured so that firmware can be loaded. On machine shutdown, hotplug can be disabled before networking interfaces, and this enables whereami to function correctly in those circumstances.

testssid ssid[,key]

Checks whether the wireless interface is in range of the specified ssid, using the key if supplied. The key should be formatted as for iwconfig. What works for me looks like da18babe100ea4beadb74324bc ("128" bits) or fe3d1b3ed7 (40 bits).

This script will also respond to a TIMEOUT variable which is set before it is called, but waiting for $TIMEOUT seconds for the network to settle (default 2).

This is useful for checking which wireless LAN is in range.

testreceived [interface]

Checks whether the interface in question has received any bytes.

This is useful for checking which network interface is actually connected to a network.