Posts

In the previous blog about the program execution environment, we introduced the concept of stack unwinding with frame pointers as one of the techniques leveraged for profiling a program. In this blog, we’ll see practically how we can build a simple sampling-based continuous profiler. Since we don’t want the application to necessarily be instrumented, we can use the Linux kernel instrumentation. Thanks to eBPF we’re able to dynamically load and attach the profiler program to specific kernel entry points, limiting the introduced overhead by exchanging data with userspace through eBPF maps....

Profiling the CPU allows us to analyze the program’s performance, identify bottlenecks, and optimize its efficiency. Have you ever wondered what happens behind the scenes when you run a program and how to account for CPU time for the actual program functions? And even more, how to write such a tool to profile the program? Even though great open-source projects provide continuous profiling with vast support for compiled, JITed, and interpreted, languages, with or without debug info, with or without frame pointers, etc....

Introduction wfind is a simple web crawler for files and folders in web pages hyerarchies. The goal is basically the same of GNU find for file systems. At the same time it’s inspired by GNU wget, and it merges the find features applied to files and directories exposed as HTML web resources. In this blog we’ll go through the way I improved consistency in this crawler, by implementing retry logics and tuning network and transport in the HTTP client....

Two years ago more or less I started my journey in Linux. I was scared at first and I didn’t know where to start from. But then I decided to buy a book - and what a book! - in order to follow a path. Along the way, I integrated the material with up-to-date documentation from kernel.org and source code. In the meantime, I started to learn C a bit so that I also could have played with what I was learning, step by step....

Hello everyone, a long time has passed after the 5th part of this journey through STRIDE thread modeling in Kubernetes has been published. If you recall well, STRIDE is a model of threats for identifying security threats, by providing a mnemonic for security threats in six categories: Spoofing Tampering Repudiation Information disclosure Denial of service Elevation of privilege In this last chapter we’ll talk about elevation of privilege. Well, this category can be very wide, but let’s start thinking about what it can comprises and what we can do against this category of threats....