SemaphoreSecurity.RemoveAccessRuleSpecific(SemaphoreAccessRule) Method
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Searches for an access control rule that exactly matches the specified rule and, if found, removes it.
public:
void RemoveAccessRuleSpecific(System::Security::AccessControl::SemaphoreAccessRule ^ rule);public void RemoveAccessRuleSpecific (System.Security.AccessControl.SemaphoreAccessRule rule);override this.RemoveAccessRuleSpecific : System.Security.AccessControl.SemaphoreAccessRule -> unitPublic Sub RemoveAccessRuleSpecific (rule As SemaphoreAccessRule)Parameters
- rule
- SemaphoreAccessRule
The SemaphoreAccessRule to remove.
Exceptions
rule is null.
Examples
The following code example shows that the RemoveAccessRuleSpecific method requires an exact match in order to remove a rule, and that rules to allow and deny rights are independent of each other.
The example creates a SemaphoreSecurity object, adds rules that allow and deny various rights for the current user, and then merges additional rights into the Allow access rule. The example then passes the original Allow rule to the RemoveAccessRuleSpecific method, and displays the results, showing that nothing is deleted. The example then constructs a rule that matches the Allow rule in the SemaphoreSecurity object, and successfully uses the RemoveAccessRuleSpecific method to remove the rule.
Note
This example does not attach the security object to a Semaphore object. Examples that attach security objects can be found in Semaphore.GetAccessControl and Semaphore.SetAccessControl.
using System;
using System.Threading;
using System.Security.AccessControl;
using System.Security.Principal;
public class Example
{
public static void Main()
{
// Create a string representing the current user.
string user = Environment.UserDomainName + "\\" +
Environment.UserName;
// Create a security object that grants no access.
SemaphoreSecurity mSec = new SemaphoreSecurity();
// Add a rule that grants the current user the
// right to enter or release the semaphore.
SemaphoreAccessRule ruleA = new SemaphoreAccessRule(user,
SemaphoreRights.Synchronize | SemaphoreRights.Modify,
AccessControlType.Allow);
mSec.AddAccessRule(ruleA);
// Add a rule that denies the current user the
// right to change permissions on the semaphore.
SemaphoreAccessRule rule = new SemaphoreAccessRule(user,
SemaphoreRights.ChangePermissions,
AccessControlType.Deny);
mSec.AddAccessRule(rule);
// Display the rules in the security object.
ShowSecurity(mSec);
// Add a rule that allows the current user the
// right to read permissions on the semaphore. This rule
// is merged with the existing Allow rule.
rule = new SemaphoreAccessRule(user,
SemaphoreRights.ReadPermissions,
AccessControlType.Allow);
mSec.AddAccessRule(rule);
ShowSecurity(mSec);
// Attempt to remove the original rule (granting
// the right to enter or release the semaphore) with
// RemoveAccessRuleSpecific. The removal fails,
// because the right to read the permissions on the
// semaphore has been added to the rule, so that it no
// longer matches the original rule.
Console.WriteLine("Attempt to use RemoveAccessRuleSpecific on the original rule.");
mSec.RemoveAccessRuleSpecific(ruleA);
ShowSecurity(mSec);
// Create a rule that grants the current user
// the right to enter or release the semaphore, and
// to read permissions. Use this rule to remove
// the Allow rule for the current user.
Console.WriteLine("Use RemoveAccessRuleSpecific with the correct rights.");
rule = new SemaphoreAccessRule(user,
SemaphoreRights.Synchronize | SemaphoreRights.Modify |
SemaphoreRights.ReadPermissions,
AccessControlType.Allow);
mSec.RemoveAccessRuleSpecific(rule);
ShowSecurity(mSec);
}
private static void ShowSecurity(SemaphoreSecurity security)
{
Console.WriteLine("\r\nCurrent access rules:\r\n");
foreach(SemaphoreAccessRule ar in
security.GetAccessRules(true, true, typeof(NTAccount)))
{
Console.WriteLine(" User: {0}", ar.IdentityReference);
Console.WriteLine(" Type: {0}", ar.AccessControlType);
Console.WriteLine(" Rights: {0}", ar.SemaphoreRights);
Console.WriteLine();
}
}
}
/*This code example produces output similar to following:
Current access rules:
User: TestDomain\TestUser
Type: Deny
Rights: ChangePermissions
User: TestDomain\TestUser
Type: Allow
Rights: Modify, Synchronize
Current access rules:
User: TestDomain\TestUser
Type: Deny
Rights: ChangePermissions
User: TestDomain\TestUser
Type: Allow
Rights: Modify, ReadPermissions, Synchronize
Attempt to use RemoveAccessRuleSpecific on the original rule.
Current access rules:
User: TestDomain\TestUser
Type: Deny
Rights: ChangePermissions
User: TestDomain\TestUser
Type: Allow
Rights: Modify, ReadPermissions, Synchronize
Use RemoveAccessRuleSpecific with the correct rights.
Current access rules:
User: TestDomain\TestUser
Type: Deny
Rights: ChangePermissions
*/
Imports System.Threading
Imports System.Security.AccessControl
Imports System.Security.Principal
Public Class Example
Public Shared Sub Main()
' Create a string representing the current user.
Dim user As String = Environment.UserDomainName _
& "\" & Environment.UserName
' Create a security object that grants no access.
Dim mSec As New SemaphoreSecurity()
' Add a rule that grants the current user the
' right to enter or release the semaphore.
Dim ruleA As New SemaphoreAccessRule(user, _
SemaphoreRights.Synchronize _
Or SemaphoreRights.Modify, _
AccessControlType.Allow)
mSec.AddAccessRule(ruleA)
' Add a rule that denies the current user the
' right to change permissions on the semaphore.
Dim rule As New SemaphoreAccessRule(user, _
SemaphoreRights.ChangePermissions, _
AccessControlType.Deny)
mSec.AddAccessRule(rule)
' Display the rules in the security object.
ShowSecurity(mSec)
' Add a rule that allows the current user the
' right to read permissions on the semaphore. This rule
' is merged with the existing Allow rule.
rule = New SemaphoreAccessRule(user, _
SemaphoreRights.ReadPermissions, _
AccessControlType.Allow)
mSec.AddAccessRule(rule)
ShowSecurity(mSec)
' Attempt to remove the original rule (granting
' the right to enter or release the semaphore) with
' RemoveAccessRuleSpecific. The removal fails,
' because the right to read the permissions on the
' semaphore has been added to the rule, so that it no
' longer matches the original rule.
Console.WriteLine("Attempt to use RemoveAccessRuleSpecific on the original rule.")
mSec.RemoveAccessRuleSpecific(ruleA)
ShowSecurity(mSec)
' Create a rule that grants the current user
' the right to enter or release the semaphore, and
' to read permissions. Use this rule to remove
' the Allow rule for the current user.
Console.WriteLine("Use RemoveAccessRuleSpecific with the correct rights.")
rule = New SemaphoreAccessRule(user, _
SemaphoreRights.Synchronize _
Or SemaphoreRights.Modify _
Or SemaphoreRights.ReadPermissions, _
AccessControlType.Allow)
mSec.RemoveAccessRuleSpecific(rule)
ShowSecurity(mSec)
End Sub
Private Shared Sub ShowSecurity(ByVal security As SemaphoreSecurity)
Console.WriteLine(vbCrLf & "Current access rules:" & vbCrLf)
For Each ar As SemaphoreAccessRule In _
security.GetAccessRules(True, True, GetType(NTAccount))
Console.WriteLine(" User: {0}", ar.IdentityReference)
Console.WriteLine(" Type: {0}", ar.AccessControlType)
Console.WriteLine(" Rights: {0}", ar.SemaphoreRights)
Console.WriteLine()
Next
End Sub
End Class
'This code example produces output similar to following:
'
'Current access rules:
'
' User: TestDomain\TestUser
' Type: Deny
' Rights: ChangePermissions
'
' User: TestDomain\TestUser
' Type: Allow
' Rights: Modify, Synchronize
'
'
'Current access rules:
'
' User: TestDomain\TestUser
' Type: Deny
' Rights: ChangePermissions
'
' User: TestDomain\TestUser
' Type: Allow
' Rights: Modify, ReadPermissions, Synchronize
'
'Attempt to use RemoveAccessRuleSpecific on the original rule.
'
'Current access rules:
'
' User: TestDomain\TestUser
' Type: Deny
' Rights: ChangePermissions
'
' User: TestDomain\TestUser
' Type: Allow
' Rights: Modify, ReadPermissions, Synchronize
'
'Use RemoveAccessRuleSpecific with the correct rights.
'
'Current access rules:
'
' User: TestDomain\TestUser
' Type: Deny
' Rights: ChangePermissions
Remarks
The rule is removed only if it exactly matches rule in all details, including flags. Other rules with the same user and AccessControlType are not affected.
Important
A rule represents one or more underlying access control entries (ACE), and these entries are split or combined as necessary when you modify the access security rules for a user. Thus, a rule might no longer exist in the specific form it had when it was added, and in that case the RemoveAccessRuleSpecific method cannot remove it.
