You want to modify an attribute that contains a bit flag.
22.214.171.124 Using VBScript
' This code safely modifies a bit-flag attribute ' ------ SCRIPT CONFIGURATION ------ strObject = "<ObjectDN>" ' e.g. cn=jsmith,cn=users,dc=rallencorp,dc=com strAttr = "<AttrName>" ' e.g. rallencorp-UserProperties boolEnableBit = <TRUEorFALSE> ' e.g. FALSE intBit = <BitValue> ' e.g. 16 ' ------ END CONFIGURATION --------- set objObject = GetObject("LDAP://" & strObject) intBitsOrig = objObject.Get(strAttr) intBitsCalc = CalcBit(intBitsOrig, intBit, boolEnableBit) if intBitsOrig <> intBitsCalc then objObject.Put strAttr, intBitsCalc objObject.SetInfo WScript.Echo "Changed " & strAttr & " from " & intBitsOrig & " to " & intBitsCalc else WScript.Echo "Did not need to change " & strAttr & " (" & intBitsOrig & ")" end if Function CalcBit(intValue, intBit, boolEnable) CalcBit = intValue if boolEnable = TRUE then CalcBit = intValue Or intBit else if intValue And intBit then CalcBit = intValue Xor intBit end if end if End Function
In Recipe 4.9, I described how to search against attributes that contain a bit flag, which are used to encode various settings about an object in a single attribute. As a quick recap, you need to use a logical OR operation to match any bits being searched against, and logical AND to match a specific set of bits. If you want to set an attribute that is a bit flag, you need to take special precautions to ensure you don't overwrite an existing bit. Let's consider an example. RAllenCorp wants to secretly store some non-politically correct information about its users, including things like whether the user is really old or has big feet. They don't want to create attributes such as rallencorp-UserHasBigFeet so they decide to encode the properties in a single bit flag attribute. They decide to call the attribute rallencorp-UserProperties with the following possible bit values:
After they extend the schema to include the new attribute, they need to initially populate the attribute for all their users. To do so they can simply logically OR the values together that apply to each user. So if settings 4 and 8 apply to the jsmith user, his rallencorp-UserProperties would be set to 12 (4 OR 8). No big deal so far. The issue comes in when they need to modify the attribute in the future.
They later find out that the jsmith user was a former basketball player and is 6'8". They need to set the 2 bit (for being tall) in his rallencorp-UserProperties attribute. To set the 2 bit they need to first determine if it has already been set. If it has already been set, then there is nothing to do. If the 2 bit hasn't been set, they need to logical OR 2 with the existing value of jsmith's rallencorp-UserProperties attribute. If they simply set the attribute to 2, it would overwrite the 4 and 8 bits that had been set previously. In the VBScript solution, they could use the CalcBit function to determine the new value:
intBitsCalc = CalcBit(intBitsOrig, 2, TRUE)
The result would be 14 (12 OR 2).
The same logic applies if they want to remove a bit, except the XOR logical operator is used.
4.12.4 See Also
Recipe 4.9 for searching with a bit-wise filter