Skip to content
Snippets Groups Projects
Commit e7521c21 authored by Peter Gerwinski's avatar Peter Gerwinski
Browse files

20150504: Einführung Kernel-Module

parent 9268b293
No related branches found
No related tags found
No related merge requests found
obj-m += chardev.o
all:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
clean:
make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean
/*
* chardev.c: Creates a read-only char device that says how many times
* you've read from the dev file
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <asm/uaccess.h> /* for put_user */
/*
* Prototypes - this would normally go in a .h file
*/
int init_module(void);
void cleanup_module(void);
static int device_open(struct inode *, struct file *);
static int device_release(struct inode *, struct file *);
static ssize_t device_read(struct file *, char *, size_t, loff_t *);
static ssize_t device_write(struct file *, const char *, size_t, loff_t *);
#define SUCCESS 0
#define DEVICE_NAME "chardev" /* Dev name as it appears in /proc/devices */
#define BUF_LEN 80 /* Max length of the message from the device */
/*
* Global variables are declared as static, so are global within the file.
*/
static int Major; /* Major number assigned to our device driver */
static int Device_Open = 0; /* Is device open?
* Used to prevent multiple access to device */
static char msg[BUF_LEN]; /* The msg the device will give when asked */
static char *msg_Ptr;
static struct file_operations fops = {
.read = device_read,
.write = device_write,
.open = device_open,
.release = device_release
};
/*
* This function is called when the module is loaded
*/
int init_module(void)
{
Major = register_chrdev(0, DEVICE_NAME, &fops);
if (Major < 0) {
printk(KERN_ALERT "Registering char device failed with %d\n", Major);
return Major;
}
printk(KERN_INFO "I was assigned major number %d. To talk to\n", Major);
printk(KERN_INFO "the driver, create a dev file with\n");
printk(KERN_INFO "'mknod /dev/%s c %d 0'.\n", DEVICE_NAME, Major);
printk(KERN_INFO "Try various minor numbers. Try to cat and echo to\n");
printk(KERN_INFO "the device file.\n");
printk(KERN_INFO "Remove the device file and module when done.\n");
return SUCCESS;
}
/*
* This function is called when the module is unloaded
*/
void cleanup_module(void)
{
/*
* Unregister the device
*/
unregister_chrdev(Major, DEVICE_NAME);
}
/*
* Methods
*/
/*
* Called when a process tries to open the device file, like
* "cat /dev/mycharfile"
*/
static int device_open(struct inode *inode, struct file *file)
{
static int counter = 0;
if (Device_Open)
return -EBUSY;
Device_Open++;
sprintf(msg, "I already told you %d times Hello world!\n", counter++);
msg_Ptr = msg;
try_module_get(THIS_MODULE);
return SUCCESS;
}
/*
* Called when a process closes the device file.
*/
static int device_release(struct inode *inode, struct file *file)
{
Device_Open--; /* We're now ready for our next caller */
/*
* Decrement the usage count, or else once you opened the file, you'll
* never get get rid of the module.
*/
module_put(THIS_MODULE);
return 0;
}
/*
* Called when a process, which already opened the dev file, attempts to
* read from it.
*/
static ssize_t device_read(struct file *filp, /* see include/linux/fs.h */
char *buffer, /* buffer to fill with data */
size_t length, /* length of the buffer */
loff_t * offset)
{
/*
* Number of bytes actually written to the buffer
*/
int bytes_read = 0;
/*
* If we're at the end of the message,
* return 0 signifying end of file
*/
if (*msg_Ptr == 0)
return 0;
/*
* Actually put the data into the buffer
*/
while (length && *msg_Ptr) {
/*
* The buffer is in the user data segment, not the kernel
* segment so "*" assignment won't work. We have to use
* put_user which copies data from the kernel data segment to
* the user data segment.
*/
put_user(*(msg_Ptr++), buffer++);
length--;
bytes_read++;
}
/*
* Most read functions return the number of bytes put into the buffer
*/
return bytes_read;
}
/*
* Called when a process writes to dev file: echo "hi" > /dev/hello
*/
static ssize_t
device_write(struct file *filp, const char *buff, size_t len, loff_t * off)
{
printk(KERN_ALERT "Sorry, this operation isn't supported.\n");
return -EINVAL;
}
#include <stdio.h>
int main (void)
{
printf ("Hello, world!\n");
return 0;
}
/*
* modhello-1.c - The simplest kernel module.
*/
#include <linux/module.h> /* Needed by all modules */
#include <linux/kernel.h> /* Needed for KERN_INFO */
int init_module(void)
{
printk(KERN_INFO "Hello, world!\n");
/*
* A non 0 return means init_module failed; module can't be loaded.
*/
return 0;
}
void cleanup_module(void)
{
printk(KERN_INFO "Goodbye, world!\n");
}
/*
* modhello-2.c - Demonstrating the module_init() and module_exit() macros.
* This is preferred over using init_module() and cleanup_module().
*/
#include <linux/module.h> /* Needed by all modules */
#include <linux/kernel.h> /* Needed for KERN_INFO */
#include <linux/init.h> /* Needed for the macros */
static int __init hello_2_init(void)
{
printk(KERN_INFO "Hello, world!\n");
return 0;
}
static void __exit hello_2_exit(void)
{
printk(KERN_INFO "Goodbye, world!\n");
}
module_init(hello_2_init);
module_exit(hello_2_exit);
slides/os-layers-1.jpg

45.2 KiB

slides/os-layers-2.jpg

51.2 KiB

slides/os-layers-3.jpg

52 KiB

slides/os-layers-4.jpg

52.8 KiB

slides/os-layers-5.jpg

53.2 KiB

src/Blender3D_EarthQuarterCut.jpg

31.7 KiB

File added
File added
File added
% pgslides.sty - LaTeX Settings for Lecture Slides
% Copyright (C) 2012, 2013 Peter Gerwinski
%
% This document is free software: you can redistribute it and/or
% modify it either under the terms of the Creative Commons
% Attribution-ShareAlike 3.0 License, or under the terms of the
% GNU General Public License as published by the Free Software
% Foundation, either version 3 of the License, or (at your option)
% any later version.
%
% This document is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this document. If not, see <http://www.gnu.org/licenses/>.
%
% You should have received a copy of the Creative Commons
% Attribution-ShareAlike 3.0 Unported License along with this
% document. If not, see <http://creativecommons.org/licenses/>.
\usepackage[latin1]{inputenc}
\usepackage[german]{babel}
\usepackage[T1]{fontenc}
\usepackage{helvet}
\renewcommand*\familydefault{\sfdefault}
\usetheme{default}
\usefonttheme{structurebold}
\setbeamertemplate{navigation symbols}{}
\setbeamersize{text margin left = 0.3cm, text margin right = 0.2cm}
\setbeamertemplate{itemize item}{$\bullet$}
\setbeamertemplate{itemize subitem}{--}
\setbeamerfont{itemize/enumerate subbody}{size=\normalsize}
\setbeamerfont{itemize/enumerate subsubbody}{size=\normalsize}
\setbeamercolor{footline}{fg=gray}
\newcommand{\sep}{~$\cdot$~}
\institute[Hochschule Bochum\sep CVH]{%
\makebox(0,0)[tl]{\includegraphics[scale=0.57]{logo-hochschule-bochum-cvh-text.pdf}}\hfill
\makebox(0,0)[tr]{\includegraphics[scale=0.5]{logo-hochschule-bochum.pdf}}%
}
\iffalse
\setbeamertemplate{footline}{}
\else
\setbeamertemplate{footline}{%
\leavevmode%
\hbox to \textwidth{%
\usebeamercolor{footline}%
\usebeamerfont{footline}%
\iftrue
\strut\hfill
\else
\,\insertshorttitle\sep
\insertshortauthor\sep
\insertshortinstitute\sep
\insertshortdate\hfill
\fi
Folie\,\insertframenumber\sep Seite\,\insertpagenumber\,
}%
\vskip0pt%
}
\fi
\newcommand{\maketitleframe}{%
\begin{frame}[t,plain]
\insertinstitute
\par\vfill
\begin{center}
{\LARGE\color{structure}\inserttitle}\\[2\bigskipamount]
{\large \insertauthor}\\[1.5\bigskipamount]
\insertdate
\end{center}
\end{frame}
}
\usepackage{pstricks}
\newrgbcolor{lightyellow}{0.95 0.85 0.0}
\newrgbcolor{lightorange}{1.0 0.7 0.0}
\newrgbcolor{lightgreen}{0.0 0.8 0.0}
\newrgbcolor{medgreen}{0.0 0.5 0.0}
\newrgbcolor{darkgreen}{0.0 0.3 0.0}
\newrgbcolor{lightred}{1.0 0.7 0.7}
\newrgbcolor{lightgray}{0.85 0.85 0.85}
\definecolor{darkgray}{rgb}{0.4,0.4,0.4}
\newenvironment{experts}{\color{darkgray}}{}
\catcode`\_=13\def_{\kern1pt\rule{0.4em}{0.9pt}\kern1pt}\catcode`\_=8
\catcode`\/=13\def/#1{\ifx#1/\char`\/\kern-2pt\char`\/\else\char`\/#1\fi}\catcode`\/=12
\renewcommand{\url}[1]{{\color{structure}\catcode`~=12\catcode`##=12\catcode`_=13\catcode`/=13\textsf{#1}}}
\usepackage{listings}
\lstset{basicstyle=\color{structure},
language=C,
captionpos=b,
gobble=4,
columns=fullflexible,
aboveskip=0pt,
belowskip=0pt,
moredelim=**[is][\color{structure}]{}{},
moredelim=**[is][\only<2->{\color{structure}}]{}{},
moredelim=**[is][\only<3->{\color{structure}}]{}{},
moredelim=**[is][\only<4->{\color{structure}}]{}{},
moredelim=**[is][\only<5->{\color{structure}}]{}{},
moredelim=**[is][\only<6->{\color{structure}}]{}{},
moredelim=**[is][\only<7->{\color{structure}}]{}{},
moredelim=**[is][\only<8->{\color{structure}}]{}{}}
\lstdefinestyle{terminal}{basicstyle=\ttfamily\color{darkgreen},
language={},
columns=fixed,
moredelim=**[is][\color{red}]{}{},
moredelim=**[is][\color{blendedblue}]{}{},
moredelim=**[is][\sffamily\it\lstset{columns=fullflexible}]{}{}}
\lstdefinestyle{cmd}{basicstyle=\ttfamily\color{red},
language={},
gobble=2,
columns=fixed,
moredelim=**[is][\color{darkgreen}]{}{},
moredelim=**[is][\color{structure}]{}{},
moredelim=**[is][\sffamily\it\lstset{columns=fullflexible}]{}{}}
\lstdefinestyle{shy}{basicstyle=\color{lightgray}}
\setcounter{topnumber}{3}
\renewcommand\topfraction{0.7}
\setcounter{bottomnumber}{3}
\renewcommand\bottomfraction{0.7}
\setcounter{totalnumber}{5}
\renewcommand\textfraction{0.1}
\renewcommand\floatpagefraction{0.9}
\setlength{\unitlength}{1cm}
\newcommand{\protectfile}[1]{#1}
\newcommand{\file}[1]{{\color{structure}\protectfile{#1}}}
\newcommand{\textarrow}{{\boldmath $\longrightarrow$}}
\newcommand{\arrowitem}{\item[\textarrow]}
\newcommand{\newterm}[1]{\emph{\color{darkgreen}#1}}
\newcommand{\BIGskip}{\vspace{1cm}}
\newcommand{\shy}{\color{lightgray}}
\newcommand{\hot}{\color{red}}
\newcommand{\shyhot}{\color{lightred}}
\newcommand{\sectionnonumber}[1]{\section{#1}\addtocounter{section}{-1}}
\def\showsectionnonumber{{\Large\color{structure}\bf\secname\par}\bigskip}
\def\showsection{\hbox{\Large\color{structure}\bf
\vtop{\hbox{\arabic{section}}}\kern1em%
\vtop{\secname}\par}\bigskip}
\newcommand{\subsectionnonumber}[1]{\subsection{#1}\addtocounter{subsection}{-1}}
\def\showsubsectionnonumber{{\large\color{structure}\bf\subsecname\par}\bigskip}
\def\showsubsection{\hbox{\large\color{structure}\bf
\vtop{\hbox{\arabic{section}.\arabic{subsection}}}\kern1em%
\vtop{\subsecname}\par}\bigskip}
\newcommand{\subsubsectionnonumber}[1]{\subsubsection{#1}\addtocounter{subsubsection}{-1}}
\def\showsubsubsectionnonumber{{\normalsize\color{structure}\bf\subsubsecname\par}\bigskip}
\def\showsubsubsection{\hbox{\normalsize\color{structure}\bf
\vtop{\hbox{\arabic{section}.\arabic{subsection}.\arabic{subsubsection}}}\kern1em%
\vtop{\subsubsecname}\par}\bigskip}
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Please register or to comment