1.2. SystemTap Capabilities
SystemTap was originally developed to provide functionality for Red Hat Enterprise Linux 5 similar to previous Linux probing tools such as dprobes and the Linux Trace Toolkit. SystemTap aims to supplement the existing suite of Linux monitoring tools by providing users with the infrastructure to track kernel activity. In addition, SystemTap combines this capability with two things:
- Flexibility: SystemTap's framework allows users to develop simple scripts for investigating and monitoring a wide variety of kernel functions, system calls, and other events that occur in kernel-space. With this, SystemTap is not so much a tool as it is a system that allows you to develop your own kernel-specific forensic and monitoring tools.
- Ease-Of-Use: as mentioned earlier, SystemTap allows users to probe kernel-space events without having to resort to instrument, recompile, install, and reboot the kernel.
Most of the SystemTap scripts enumerated in Chapter 4, Useful SystemTap Scripts demonstrate system forensics and monitoring capabilities not natively available with other similar tools (such as
top, oprofile, or ps). These scripts are provided to give readers extensive examples of the application of SystemTap, which in turn will educate them further on the capabilities they can employ when writing their own SystemTap scripts.
Limitations
The current iteration of SystemTap allows for a multitude of options when probing kernel-space events. However, SystemTap's ability to probe user-space events is quite limited. At present, the developmental efforts of the SystemTap community are geared towards improving SystemTap's user-space probing capabilities.
