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Windows service

From Wikipedia, the free encyclopedia

In Windows NT operating systems, a Windows service is a computer program that operates in the background.[1] It is similar in concept to a Unix daemon.[1] A Windows service must conform to the interface rules and protocols of the Service Control Manager, the component responsible for managing Windows services. It is the Services and Controller app, services.exe, that launches all the services and manages their actions, such as start, end, etc.[2]

Windows services can be configured to start when the operating system is started and run in the background as long as Windows is running. Alternatively, they can be started manually or by an event. Windows NT operating systems include numerous services which run in context of three user accounts: System, Network Service and Local Service. These Windows components are often associated with Host Process for Windows Services. Because Windows services operate in the context of their own dedicated user accounts, they can operate when a user is not logged on.

Prior to Windows Vista, services installed as an "interactive service" could interact with Windows desktop and show a graphical user interface. In Windows Vista, however, interactive services are deprecated and may not operate properly, as a result of Windows Service hardening.[3][4]

Administration

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Windows administrators can manage services via:

Services snap-in

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The Services snap-in, built upon Microsoft Management Console, can connect to the local computer or a remote computer on the network, enabling users to:[1]

  • view a list of installed services along with service name, descriptions and configuration
  • start, stop, pause or restart services[5]
  • specify service parameters when applicable
  • change the startup type. Acceptable startup types include:
    • Automatic: The service starts at system startup.
    • Automatic (Delayed): The service starts a short while after the system has finished starting up. This option was introduced in Windows Vista in an attempt to reduce the boot-to-desktop time. However, not all services support delayed start.[6]
    • Manual: The service starts only when explicitly summoned.
    • Disabled: The service is disabled. It will not run.
  • change the user account context in which the service operates
  • configure recovery actions that should be taken if a service fails
  • inspect service dependencies, discovering which services or device drivers depend on a given service or upon which services or device drivers a given service depends
  • export the list of services as a text file or as a CSV file

Command line

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sc
Developer(s)Microsoft, ReactOS Contributors
Operating systemWindows, ReactOS
TypeCommand
LicenseWindows: Proprietary commercial software
ReactOS: GNU General Public License
Websitedocs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-R2-and-2012/cc754599(v%3dws.11)

The command-line tool to manage Windows services is sc.exe. It is available for all versions of Windows NT.[7] This utility is included with Windows XP[8] and later[9] and also in ReactOS.

The sc command's scope of management is restricted to the local computer. However, starting with Windows Server 2003, not only can sc do all that the Services snap-in does, but it can also install and uninstall services.[9]

The sc command duplicates some features of the net command.[10]

The ReactOS version was developed by Ged Murphy and is licensed under the GPL.[11]

sc sub-commands
Name Description Windows support ReactOS support
query Show service status Yes Yes
queryex Show extended service info (e.g. pid, flags) Yes Yes
start Start a service Yes Yes
pause Pause a service Yes Yes
interrogate Send an INTERROGATE control request to a service Yes Yes
continue Continue a service Yes Yes
stop Stop a service Yes Yes
config permanently change the service configuration Yes Yes
description Change a service description Yes Yes
failure Change the actions taken by a service upon failure Yes Yes
failureflag Yes No
sidtype Yes No
privs Yes No
managedaccount Yes No
qc Show the service config (e.g. dependencies, full path etc.) Yes Yes
qdescription Query a service description Yes Yes
qfailure Yes No
qfailureflag Yes No
qsidtype Yes No
qprivs Yes No
qtriggerinfo Yes No
qpreferrednode Yes No
qmanagedaccount Yes No
qprotection Yes No
quserservice Yes No
delete Delete a service Yes Yes
create Create a service Yes Yes
control Send a control to a service Yes Yes
sdshow Display a service's security descriptor using SDDL Yes Yes
sdset Sets a service's security descriptor using SDDL Yes Yes
showsid Yes No
triggerinfo Yes No
preferrednode Yes No
GetDisplayName Show the service DisplayName Yes Yes
GetKeyName Show the service ServiceKeyName Yes Yes
EnumDepend Show the service Dependencies Yes Yes
boot Yes No
Lock Yes No
QueryLock Yes No

Examples

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The following example enumerates the status for active services & drivers.[12] 

C:\>sc query

The following example displays the status for the Windows Event log service.[12] 

C:\>sc query eventlog

PowerShell

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The Microsoft.PowerShell.Management PowerShell module (included with Windows) has several cmdlets which can be used to manage Windows services:

Other management tools

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Windows also includes components that can do a subset of what the snap-in, Sc.exe and PowerShell do. The net command can start, stop, pause or resume a Windows service.[21] In Windows Vista and later, Windows Task Manager can show a list of installed services and start or stop them. MSConfig can enable or disable (see startup type description above) Windows services.

Installation

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Windows services are installed and removed via *.INF setup scripts by SetupAPI; an installed service can be started immediately following its installation, and a running service can be stopped before its deinstallation.[22][23][24]

Development

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Writing native services

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For a program to run as a Windows service, the program needs to be written to handle service start, stop, and pause messages from the Service Control Manager (SCM) through the System Services API. SCM is the Windows component responsible for managing service processes.

Wrapping applications as a service

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The Windows Resource Kit for Windows NT 3.51, Windows NT 4.0 and Windows 2000 provides tools to control the use and registration of services: SrvAny.exe acts as a service wrapper to handle the interface expected of a service (e.g. handle service_start and respond sometime later with service_started or service_failed) and allow any executable or script to be configured as a service. Sc.exe allows new services to be installed, started, stopped and uninstalled.[25]

See also

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Windows services
Concept

References

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  1. ^ a b c "Services overview". TechNet. Microsoft. Retrieved 29 March 2013.
  2. ^ "Services". Microsoft Developer Network. Microsoft. Retrieved 29 March 2013.
  3. ^ "New Elevation PowerToys for Windows Vista". TechNet Magazine. Microsoft. June 2008. Retrieved 21 June 2013. The service CmdAsSystem is configured as interactive whose support is being deprecated. The service may not function properly. The problem is that this script tries to create and start an interactive service. Interactive services will not function correctly due to Session 0 Isolation in Windows Vista.
  4. ^ "Services in Windows". MSDN. Microsoft. 18 October 2010. Retrieved 21 June 2013.
  5. ^ "Start, stop, pause, resume, or restart a service". TechNet. Microsoft. Retrieved 29 March 2013.
  6. ^ "ServiceInstaller.DelayedAutoStart Property (System.ServiceProcess)". Microsoft. Retrieved 28 November 2017See Remarks section{{cite web}}: CS1 maint: postscript (link)
  7. ^ "How to create a Windows service by using Sc.exe". Support. Microsoft. 11 September 2011. Retrieved 29 March 2013.
  8. ^ "Command-line reference A-Z: SC". TechNet. Microsoft. Retrieved 8 January 2014.
  9. ^ a b "Command-Line Reference: Sc". TechNet. Microsoft. Retrieved 8 January 2014. Windows 7, Windows 8, Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Vista
  10. ^ SC - Service Control - Windows CMD - SS64.com
  11. ^ reactos/sc.c at master · reactos/reactos · GitHub
  12. ^ a b MS-DOS and Windows command line sc command
  13. ^ "Get-Service". TechNet. Microsoft. Retrieved 29 March 2013.
  14. ^ "New-Service". TechNet. Microsoft. Retrieved 29 March 2013.
  15. ^ "Restart-Service". TechNet. Microsoft. Retrieved 29 March 2013.
  16. ^ "Resume-Service". TechNet. Microsoft. Retrieved 29 March 2013.
  17. ^ "Set-Service". TechNet. Microsoft. Retrieved 29 March 2013.
  18. ^ "Start-Service". TechNet. Microsoft. Retrieved 29 March 2013.
  19. ^ "Stop-Service". TechNet. Microsoft. Retrieved 29 March 2013.
  20. ^ "Suspend-Service". TechNet. Microsoft. Retrieved 29 March 2013.
  21. ^ "Start, stop, pause, resume, or restart a service". TechNet. Microsoft. Retrieved 8 January 2014.
  22. ^ "INF AddService Directive". Microsoft. Retrieved 10 July 2017.
  23. ^ "SetupInstallServicesFromInfSection function". MSDN. Microsoft. Retrieved 10 July 2017.
  24. ^ "SetupInstallServicesFromInfSectionEx function". MSDN. Microsoft. Retrieved 10 July 2017.
  25. ^ "How To Create a User-Defined Service". Support. Microsoft. Retrieved 29 March 2013.

Further reading

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Wikibooks has a book on the topic of: Guide to Windows Commands
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