AIX Event Infrastructure kernel extension

The AIX® Event Infrastructure kernel extension implements the pseudo file system.

All events are represented as files in this file system. There are four file object types:

• .list files: There is only one .list file in the pseudo file system evProds.list. This is a special file which when read, will return the names of all currently defined event producers.
• .monFactory directories: Monitor factories are a special type of directory. These are directory representations of the event producers. Monitor factory directories and their parent subdirectories are automatically created for the user.
• subdirectories: Sub directories are used both for ease of management and to represent full path names for monitor files (see .mon files).
• .mon files: The monitor files represent the events that can be monitored. The full pathname of a monitor file from its parent monitor factory, minus the .mon extension is the full representation of the event being monitored. For example, the file /aha/fs/modFile.monFactory/etc/password.mon is used to monitor the modifications to the /etc/passwd file. Monitor files can only exist underneath a monitor factory.

No other regular files can be created in this pseudo file system. Since the AIX Event Infrastructure file system is an in-memory file system, there is a maximum of 32 KB of inodes that may exist. The number of inodes used will be displayed in the df command output.

An example of the layout of an AIX Event Infrastructure file system is shown below:

Using the LFS interface, the AIX Event Infrastructure will translate text input written to monitor files into specifications on how the user wants to be notified of event occurrences. Once a user has issued a select() or a blocking read() call to signify the beginning of their monitoring, the AIX Event Infrastructure will notify the corresponding event producer to start monitoring the specified event.

When an event occurrence is detected, the AIX Event Infrastructure will notify all waiting consumers whose monitoring criteria have been met.