Load modules in Linux Kernel

Load the module in the Linux kernel-general Linux technology-Linux programming and kernel information. The following is a detailed description. I saw how to write a driver in LINUX some time ago.

Today I wrote a try.

Write a simple small program
# Include "linux/kernel. h"
# Include "linux/module. h"
# Include "linux/version. h"
# If CONFIG_MODBERSIONS = 1
# Define MODBERSIONS
# Include "Linux. modversions. h"
# Endif
# Define devicename mydevice
MODULE_LICENSE ("GPL"); // here is a certificate for this module
/* The init funcion */
Int init_module ()
{

// Load the function of the module
Printk ("holy shit works! \ N ");

// Because PRINTF cannot work, use PRINTK. You can see the content here only by running the DMESG command.

Return 0;
}

/* The funcion which the device will be used */

Int cleanup_module ()
{

// Clear functions of the module
Printk ("holy shit works too !! \ N ");
Return 0;
}


Most of them are COPY, but I still understand it.

Compile the program after writing it. No makefile is prepared. replace it with a command.

Gcc-Wall-DMODULE-D_KENNEL _-DLinux-c test. c
I do not know the specific meaning

Compile and generate. Test. o

Then load the module with insmod test. o

An error may occur.

1. The module version is incorrect.

Solution: Modify/USR/INCLUDE/LINUX/VERSION. H. The # define UTS_RELEASE "2.4.18-3"

2. No certificate

MODULE_LICENSE ("GPL ");

3. Module busy

First, check whether the returned value of your loaded module is 0. If it is not 0, this error will certainly occur.

Use lsmod to check whether a module with the same name is running.

If yes, run the rmmod command to kill him.

4. No output is visible.

Output DMESG on the console.