Upon startup, the PICL daemon loads and initializes the plug-in modules. These modules use the libpicltree(3PICLTREE) interface to create nodes and properties in the PICL tree to publish platform configuration information. After the plug-in modules are initialized, the daemon opens the PICL daemon door to service client requests to access information in the PICL tree.
Plug-in modules are located in one of the following plug-in directories depending on the platform-specific nature of the data that they collect and publish:
/usr/platform/`uname -i`/lib/picl/plugins /usr/platform/`uname -m`/lib/picl/plugins
A plug-in module can specify its dependency on another plug-in module using the -l or -R linker option. The plug-ins are loaded by the daemon using dlopen(3C) according to the specified dependencies. Each plug-in module must define a .init section, which is executed when the plug-in module is loaded, to register themselves with the daemon. See picld_plugin_register(3PICLTREE) for additional information on plug-in registration.
The plug-in modules use the libpicltree(3PICLTREE) interface to publish nodes and properties in the PICL tree so that clients can access them.
When the PICL daemon invokes the initialization routine of the plug-in module, the plug-in collects the platform information and creates nodes and/or properties to represent the configuration in the PICL tree. A plug-in can create additional threads to monitor the platform configuration and update the PICL tree with any changes. This enables a PICL plug-in to operate as a daemon within the PICL framework.
An environmental monitor is an example of a plug-in module that uses a thread to monitor the temperatures and fan speeds of the platform, then publishes the environmental information in the PICL tree so clients can access them.
Clients use the libpicl(3PICL) interface to send requests to picld for accessing the PICL tree.
Administrative actions on this service, such as enabling, disabling, or requesting restart, can be performed using svcadm(1M). The service's status can be queried using the svcs(1) command.
|May 16, 2020|