MIT S081 Lab 2 System Calls

Lab链接

一 实现trace功能

1 题目要求

In this assignment you will add a system call tracing feature that may help you when debugging later labs. You'll create a new trace system call that will control tracing. It should take one argument, an integer "mask", whose bits specify which system calls to trace. For example, to trace the fork system call, a program calls trace(1 << SYS_fork), where SYS_fork is a syscall number from kernel/syscall.h. You have to modify the xv6 kernel to print out a line when each system call is about to return, if the system call's number is set in the mask. The line should contain the process id, the name of the system call and the return value; you don't need to print the system call arguments. The trace system call should enable tracing for the process that calls it and any children that it subsequently forks, but should not affect other processes.

We provide a trace user-level program that runs another program with tracing enabled (see user/trace.c). When you're done, you should see output like this:

cpp 复制代码
$ trace 32 grep hello README
3: syscall read -> 1023
3: syscall read -> 966
3: syscall read -> 70
3: syscall read -> 0
$
$ trace 2147483647 grep hello README
4: syscall trace -> 0
4: syscall exec -> 3
4: syscall open -> 3
4: syscall read -> 1023
4: syscall read -> 966
4: syscall read -> 70
4: syscall read -> 0
4: syscall close -> 0
$
$ grep hello README
$
$ trace 2 usertests forkforkfork
usertests starting
test forkforkfork: 407: syscall fork -> 408
408: syscall fork -> 409
409: syscall fork -> 410
410: syscall fork -> 411
409: syscall fork -> 412
410: syscall fork -> 413
409: syscall fork -> 414
411: syscall fork -> 415
...
$   

trace是一个运行在用户空间的程序。 你需要实现一个用户空间程序 trace,它将启动另一个程序并启用跟踪功能。

trace调用时,会传入一个int类型的mask值,来指明需要对哪些系统调用trace。

获取argument,获取系统调用号、

相关推荐
前端_学习之路20 分钟前
React--Fiber 架构
前端·react.js·架构
伍哥的传说38 分钟前
React 实现五子棋人机对战小游戏
前端·javascript·react.js·前端框架·node.js·ecmascript·js
古希腊数通小白(ip在学)44 分钟前
stp拓扑变化分类
运维·服务器·网络·智能路由器
qq_424409191 小时前
uniapp的app项目,某个页面长时间无操作,返回首页
前端·vue.js·uni-app
我在北京coding1 小时前
element el-table渲染二维对象数组
前端·javascript·vue.js
布兰妮甜1 小时前
Vue+ElementUI聊天室开发指南
前端·javascript·vue.js·elementui
SevgiliD1 小时前
el-button传入icon用法可能会出现的问题
前端·javascript·vue.js
我在北京coding1 小时前
Element-Plus-全局自动引入图标组件,无需每次import
前端·javascript·vue.js
柚子8161 小时前
scroll-marker轮播组件不再难
前端·css
Muxiyale1 小时前
使用spring发送邮件,部署ECS服务器
java·服务器·spring