在Minix中添加新的系统调用 [英] Adding new System Call in Minix
问题描述
我正在尝试在Minix 3.3中创建一个新的系统调用.首先，我只是想创建一个简单的printmsg()调用，该调用将在屏幕上显示"Hello World".
我在互联网上浏览了各种教程，但仍然找不到解决方案.
I am trying to create a new system call in Minix 3.3. At first i just want to create simple printmsg() call that will write "Hello World" on screen.
I looked various tutorials on internet and still couldn't find out solution.
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我像这样
#define PM_PRINTMSG (PM BASE + 48)在 callnr.h 中定义了系统调用号码，并且增加了#define NR_PM_CALLS 49的系统调用次数.
I defined my sys call number in callnr.h like this
#define PM_PRINTMSG (PM BASE + 48)and i increased number of sys calls#define NR_PM_CALLS 49.
在 table.c 中，我添加了CALL(PM_PRINTMSG) = doprintmsg.
在 proto.h 中，我描述了函数原型`int do_printmsg(void);
In proto.h I described function prototype `int do_printmsg(void);
函数实现是用 misc.c 编写的.我添加了#include <stdio.h>并设置了Hello World函数int do printmsg(){ printf("I am a system call"); return 0; }
Function implementation is written in misc.c. I added #include <stdio.h> and made Hello World function int do printmsg(){ printf("I am a system call"); return 0; }
当我在用户程序_syscall(PM_PROC_NR, PM_PRINTMSG, &m);中测试系统调用时，我没有收到任何错误，但没有显示printf.
When I test my system call in user program _syscall(PM_PROC_NR, PM_PRINTMSG, &m); I don't get any errors but no printf is displayed.
因此，是否可以从系统调用中打印消息，因为我必须在 misc.c 中自己添加<stdio.h>，或者我错过了一些步骤.我忘了提到我进入/usr/src/releasetools并分别键入make services和make install来重新编译内核.
So, is it possible to printf messages from system calls since i had to add <stdio.h> myself in misc.c or i missed some steps. I forgot to mention that i go in /usr/src/releasetools and type make services and make install respectively to recompile kernel.
推荐答案
我想出了问题所在，因此如果将来有人需要它，我将发布答案.在此示例中，我做得很好，但是无法编译内核.
正确的位置是usr/src/releasetools，但是所需的命令是make hdboot.另外，我发现我的PC无法与此虚拟机一起正常工作，即使我没有进行任何更改，我在编译时也遇到了许多错误.当我切换到笔记本电脑时，一切正常.
我的结论是，有时您的计算机上出现问题，因此您应该尝试在不同的计算机上测试问题
I figured out what was the problem, so i will post answer if someone needs this in future. I did everything well in this example but i failed to compile kernel.
The location was correct which is usr/src/releasetools, but command needed is make hdboot. Also i figured out my PC somehow wasnt working well with this virtual machines and i had many errors while compiling even though i didn't change anything. When i switched to laptop everything worked fine.
My conclusion is sometimes there is just something wrong on your machine so you should try and test problems on different ones
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