Capabilities (Symbian Signed)/PowerMgmt Capability

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Created: hamishwillee (16 Dec 2010)

Last edited: hamishwillee (20 Jul 2012)

The PowerMgmt capability allows an application to perform highly sensitive system functions such as killing other processes, switching the phone into standby mode and disabling 'wakeup' events (user actions which cause the phone to become active from standby mode).

This capability can be used with developer certificates and Symbian Signed tested applications, and by using open signed online for testing.

Why?:

Interfering with the functioning of the phone by killing applications, putting the device into standby or preventing it from waking from standby is highly undesirable for the user. Functions that can do this should only be performed with the user's express consent and so applications that wish to do these things must be checked.

What?:

The power management driver polices this capability when requested by the user-side power management API. The kernel checks this capability when attempting to kill other processes.

Where?:

Third-party task management applications that need to kill other processes in the system. Programs ported from posix that need to kill a running child process.

Note: On many other operating systems, a parent process can kill a child process that it created. On Symbian, this is not true - once a child process has been resumed, it is fully independent and cannot be killed by the parent unless the parent process has PowerMgmt capability. Sending some kind of "quit" message via IPC is an alternative where possible.