In the world of the Linux operating system, system calls serve as the “bridge” for user-space programs to interact with kernel-space, determining how programs access hardware resources and execute core operations. The “system call hook” technology acts like an intelligent “observation station” and “control valve” on this bridge—capable of real-time monitoring of the program’s kernel … Read more
Chapter 4: A Guide to Various Methods of Process Termination — Five Ways to Trigger a System Crash [Location: Operating Realm · Trial Ground · Outer Sect of Process School] In the realm of cultivation (Operating Realm), the ultimate fate of every cultivator (process) is often “termination”. While most cultivators aspire to achieve longevity (guarding … Read more
In the field of high-performance programming, data copying is one of the key bottlenecks affecting system throughput. In traditional IO operations, data often needs to be transferred multiple times between user space and kernel space, accompanied by redundant copying overhead.The core goal of zero-copy technology is toreduce or eliminate unnecessary data copying, significantly improving the … Read more
1. What is strace In simple terms, <span>strace</span> acts like a “listener” between your program and the operating system. Does your program want to read a file? Make a system call? Send a network request? Or make a system call?<span>strace</span> sits in the middle and records all these conversations. The most crucial part is: No … Read more
Introduction In Linux system development, we often need to perform file operations, such as reading configuration files, saving logs, or recording data. The most common methods fall into two categories: One category is System Call I/O: <span>open()</span>, <span>read()</span>, <span>write()</span>, <span>lseek()</span>, etc. The other category is C Standard Library I/O: <span>fopen()</span>, <span>fread()</span>, <span>fwrite()</span>, <span>fclose()</span>, etc. While … Read more
Process Perspective vs Kernel Perspective In a Linux system, we can understand the system’s operating mechanism from two different levels: Process Perspective and Kernel Perspective. These two perspectives have essential differences. Process Perspective: Limited “User Space” View From the process perspective, the system’s operation is filled with uncertainty and limitations: #include <stdio.h> #include <unistd.h> #include … Read more
Everyone knows that information security is crucial for every enterprise today. Safeguarding server information security is one of the essential skills for every operations engineer. Today, I will share practical insights about the kernel-level auditing tool of the Linux system—auditd, which helps you protect server information security. By using it effectively, even if hackers invade, … Read more
46. Question: You notice that a process in the Linux system is consuming too much CPU resources. Which command would you use to adjust its priority? Option 1: nice Option 2: renice Option 3: top Option 4: ps Correct Answer: 2 Explanation: To adjust the priority of a running process in Linux, you would use … Read more
If an interviewer asks you: Can you explain the principles of Linux permission allocation? Today, let’s discuss this. 1. Permission Abstraction A complete permission management system requires reasonable abstraction. This includes abstractions for users, processes, files, memory, system calls, etc. First, let’s talk about users and groups. Linux is a multi-user platform that allows multiple … Read more
GDB uses the ptrace system call to implement its functionality. This article provides a brief overview of ptrace. Ptrace The ptrace system call /* kernel/ptrace.c */ #define __NR_ptrace 117 __SYSCALL(__NR_ptrace, sys_ptrace) When using ptrace, you need to include<span>/sys/ptrace.h</span>. When calling the ptrace system call, you need to send requests based on different requests, which are … Read more