diff --git a/20210507/Makefile b/20210507/Makefile
new file mode 120000
index 0000000000000000000000000000000000000000..134aa0a7e9fd70818ec2dbee3f7201a161389434
--- /dev/null
+++ b/20210507/Makefile
@@ -0,0 +1 @@
+Makefile-modules-2
\ No newline at end of file
diff --git a/20210507/Makefile-modules-2 b/20210507/Makefile-modules-2
new file mode 100644
index 0000000000000000000000000000000000000000..f9f342647e7b471ae2f4bd105c57fb54f9591136
--- /dev/null
+++ b/20210507/Makefile-modules-2
@@ -0,0 +1,9 @@
+obj-m += chardev-1a.o
+obj-m += chardev-1b.o
+obj-m += chardev-3.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
diff --git a/20210507/attributes-1.txt b/20210507/attributes-1.txt
new file mode 100644
index 0000000000000000000000000000000000000000..e6fe61064d159cd088fa3039af59a7ffcf86eb78
--- /dev/null
+++ b/20210507/attributes-1.txt
@@ -0,0 +1,43 @@
+crw------- 1 root root 10, 137 Apr 6 09:59 vhci
+crw------- 1 root root 10, 238 Apr 6 09:59 vhost-net
+crw------- 1 root root 10, 241 Apr 6 09:59 vhost-vsock
+crw-rw----+ 1 root video 81, 0 Mai 7 10:44 video0
+crw-rw----+ 1 root video 81, 1 Mai 7 10:44 video1
+crw-rw----+ 1 root video 81, 2 Apr 28 23:30 video4
+crw------- 1 root root 10, 130 Apr 6 09:59 watchdog
+crw------- 1 root root 248, 0 Apr 6 09:59 watchdog0
+crw-rw-rw- 1 root root 1, 5 Apr 6 09:59 zero
+cassini/home/peter/bo/2021ss/bs/20210507> ls -l /dev/chardev
+crw------- 1 root root 241, 0 Mai 7 14:17 /dev/chardev
+cassini/home/peter/bo/2021ss/bs/20210507> cat /dev/chardev
+cat: /dev/chardev: Keine Berechtigung
+cassini/home/peter/bo/2021ss/bs/20210507> sudo chmod 666 /dev/chardev
+cassini/home/peter/bo/2021ss/bs/20210507> ls -l /dev/chardev
+crw-rw-rw- 1 root root 241, 0 Mai 7 14:17 /dev/chardev
+cassini/home/peter/bo/2021ss/bs/20210507> cat /dev/chardev
+I already told you 1 times Hello world!
+cassini/home/peter/bo/2021ss/bs/20210507> cat /dev/chardev
+I already told you 2 times Hello world!
+cassini/home/peter/bo/2021ss/bs/20210507> lsattr /dev/video0
+lsattr: Die Operation wird nicht unterstützt Beim Lesen der Flags von /dev/video0
+cassini/home/peter/bo/2021ss/bs/20210507> getfacl /dev/video0
+getfacl: Entferne führende '/' von absoluten Pfadnamen
+# file: dev/video0
+# owner: root
+# group: video
+user::rw-
+user:peter:rw-
+group::rw-
+mask::rw-
+other::---
+
+cassini/home/peter/bo/2021ss/bs/20210507> getfacl /dev/chardev
+getfacl: Entferne führende '/' von absoluten Pfadnamen
+# file: dev/chardev
+# owner: root
+# group: root
+user::rw-
+group::rw-
+other::rw-
+
+cassini/home/peter/bo/2021ss/bs/20210507>
diff --git a/20210507/bs-20210507.txt b/20210507/bs-20210507.txt
new file mode 100644
index 0000000000000000000000000000000000000000..cccf426e692b08140a342ad089d1ab9a69a1cab2
--- /dev/null
+++ b/20210507/bs-20210507.txt
@@ -0,0 +1,11 @@
+Von der Anwendung bis zum Kernel: libc, 07.05.2021, 15:11:00
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+apt-get source libc6
+Datei: stdio-common/printf.c
+printf() ruft vfprintf() auf.
+Datei: stdio-common/vfprintf.c
+vfprintf() ruft printf_positional() auf.
+printf_positional() ruft outstring() auf.
+outstring() ist ein Präprozessor-Macro.
+outstring() ruft PUT() auf - ebenfalls ein Präprozessor-Macro.
+PUT() ruft _IO_sputn() auf. --> in anderer Datei
diff --git a/20210507/chardev-1a.c b/20210507/chardev-1a.c
new file mode 100644
index 0000000000000000000000000000000000000000..291b052b8d200189cb53d09b9234c509f84771ba
--- /dev/null
+++ b/20210507/chardev-1a.c
@@ -0,0 +1,166 @@
+/*
+ * 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_INFO "Got user data: %s.\n", buff);
+ return len;
+}
diff --git a/20210507/chardev-1b.c b/20210507/chardev-1b.c
new file mode 100644
index 0000000000000000000000000000000000000000..574497cbdc5c931dd2f84279c200eb1c00b0ad04
--- /dev/null
+++ b/20210507/chardev-1b.c
@@ -0,0 +1,169 @@
+/*
+ * 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)
+{
+ char b[len + 1];
+ strncpy (b, buff, len);
+ b[len] = 0;
+ printk(KERN_INFO "Got user data: %s.\n", b);
+ return len;
+}
diff --git a/20210507/chardev-2.c b/20210507/chardev-2.c
new file mode 100644
index 0000000000000000000000000000000000000000..54b8e3f30a580c7896ea18a0e4358059a6c03a48
--- /dev/null
+++ b/20210507/chardev-2.c
@@ -0,0 +1,183 @@
+/*
+ * 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/device.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 *);
+
+struct class *dev_Class;
+struct device *chr_dev;
+
+#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;
+ }
+
+ // Create module class
+ printk(KERN_INFO "Creating device class LCD...\n");
+ dev_Class = class_create(THIS_MODULE,DEVICE_NAME);
+ if( dev_Class == NULL)
+ {
+ printk( KERN_ALERT "Error! Class couldn't be created!\n" );
+ return 1 ;
+ }
+ printk( KERN_INFO "Class created!\n" );
+ // Create device in /dev/...
+ printk(KERN_INFO "Creating device\n");
+ chr_dev = device_create(dev_Class, NULL, MKDEV(Major,0), NULL, DEVICE_NAME);
+
+ 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;
+}
diff --git a/20210507/chardev-3.c b/20210507/chardev-3.c
new file mode 100644
index 0000000000000000000000000000000000000000..516a074f806e3f600009b39ca912bf5ab69e3989
--- /dev/null
+++ b/20210507/chardev-3.c
@@ -0,0 +1,198 @@
+/*
+ * 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/device.h>
+#include <linux/fs.h>
+#include <asm/uaccess.h> /* for put_user */
+
+MODULE_LICENSE("GPL");
+
+/*
+ * 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 *);
+
+struct class *dev_Class;
+struct device *chr_dev;
+
+#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;
+ }
+
+ // Create module class
+ printk (KERN_INFO "Creating device class \"chardev\" ...\n");
+ dev_Class = class_create (THIS_MODULE,DEVICE_NAME);
+ if( dev_Class == NULL)
+ {
+ printk (KERN_ALERT "Error! Class couldn't be created!\n");
+ return 1;
+ }
+ printk (KERN_INFO "Class created!\n");
+ // Create device in /dev/...
+ printk (KERN_INFO "Creating device\n");
+ chr_dev = device_create (dev_Class, NULL, MKDEV (Major,0), NULL, DEVICE_NAME);
+ if (chr_dev == NULL)
+ {
+ printk( KERN_ALERT "Error! Device couldn't be created!\n" );
+ return 1 ;
+ }
+
+ return SUCCESS;
+}
+
+/*
+ * This function is called when the module is unloaded
+ */
+void cleanup_module(void)
+{
+ printk(KERN_INFO "module chardev-4 cleanup\n");
+ //Unregister the device
+ if (chr_dev)
+ {
+ printk(KERN_INFO "Unregister device ...\n");
+ device_unregister(chr_dev);
+ printk(KERN_INFO "OK\n");
+ }
+
+ if (dev_Class)
+ {
+ printk(KERN_INFO "Unregister class ...\n");
+ class_unregister(dev_Class);
+ printk(KERN_INFO "OK\n");
+ }
+
+ printk(KERN_INFO "Unregister Chardev ...\n");
+ unregister_chrdev(Major, DEVICE_NAME);
+ printk(KERN_INFO "Device %s unregistered!\n", 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;
+}
diff --git a/20210507/hello-1.c b/20210507/hello-1.c
new file mode 100644
index 0000000000000000000000000000000000000000..b19d80e9bd0bd7c5ed8f54b20c6a50d9166f03ac
--- /dev/null
+++ b/20210507/hello-1.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main (void)
+{
+ printf ("Hello, world!\n");
+ return 0;
+}
diff --git a/20210507/hello-1.s b/20210507/hello-1.s
new file mode 100644
index 0000000000000000000000000000000000000000..74d6a369cdbf391e6c0045d41640db9b020d3935
--- /dev/null
+++ b/20210507/hello-1.s
@@ -0,0 +1,24 @@
+ .file "hello-1.c"
+ .text
+ .section .rodata.str1.1,"aMS",@progbits,1
+.LC0:
+ .string "Hello, world!"
+ .text
+ .globl main
+ .type main, @function
+main:
+.LFB11:
+ .cfi_startproc # #include <stdio.h>
+ subq $8, %rsp #
+ .cfi_def_cfa_offset 16 # int main (void)
+ leaq .LC0(%rip), %rdi # {
+ call puts@PLT # printf ("Hello, world!\n");
+ movl $0, %eax # return 0;
+ addq $8, %rsp # }
+ .cfi_def_cfa_offset 8
+ ret
+ .cfi_endproc
+.LFE11:
+ .size main, .-main
+ .ident "GCC: (Debian 8.3.0-6) 8.3.0"
+ .section .note.GNU-stack,"",@progbits
diff --git a/20210507/hello-2.c b/20210507/hello-2.c
new file mode 100644
index 0000000000000000000000000000000000000000..b767f77cd3a7328e5f45b60e674d32a647386509
--- /dev/null
+++ b/20210507/hello-2.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main (void)
+{
+ puts ("Hello, world!");
+ return 0;
+}
diff --git a/20210507/hello-2.s b/20210507/hello-2.s
new file mode 100644
index 0000000000000000000000000000000000000000..272bf70d0e982b55523ac1b7ff767b6a6b4e36ac
--- /dev/null
+++ b/20210507/hello-2.s
@@ -0,0 +1,24 @@
+ .file "hello-2.c"
+ .text
+ .section .rodata.str1.1,"aMS",@progbits,1
+.LC0:
+ .string "Hello, world!"
+ .text
+ .globl main
+ .type main, @function
+main:
+.LFB11:
+ .cfi_startproc
+ subq $8, %rsp
+ .cfi_def_cfa_offset 16
+ leaq .LC0(%rip), %rdi
+ call puts@PLT
+ movl $0, %eax
+ addq $8, %rsp
+ .cfi_def_cfa_offset 8
+ ret
+ .cfi_endproc
+.LFE11:
+ .size main, .-main
+ .ident "GCC: (Debian 8.3.0-6) 8.3.0"
+ .section .note.GNU-stack,"",@progbits
diff --git a/20210507/hello-3.c b/20210507/hello-3.c
new file mode 100644
index 0000000000000000000000000000000000000000..e94ca36ea31d1cda0d9f38d132cf59fc21c08fb8
--- /dev/null
+++ b/20210507/hello-3.c
@@ -0,0 +1,12 @@
+extern int puts (char *s);
+
+void printf (void)
+{
+ puts ("Hello, world!");
+}
+
+int main (void)
+{
+ printf ();
+ return 0;
+}
diff --git a/20210507/modules-5.txt b/20210507/modules-5.txt
new file mode 100644
index 0000000000000000000000000000000000000000..c35d087df67701dfa512ab1d9a1f98a80baa519b
--- /dev/null
+++ b/20210507/modules-5.txt
@@ -0,0 +1,8 @@
+cassini/home/peter/bo/2021ss/bs/20210430> cat dev/chardev
+cat: dev/chardev: Kein passendes Gerät bzw. keine passende Adresse gefunden
+cassini/home/peter/bo/2021ss/bs/20210430> ls -l dev/chardev
+crw-rw-rw- 1 root root 241, 0 Apr 30 15:14 dev/chardev
+cassini/home/peter/bo/2021ss/bs/20210430> sudo cat dev/chardev
+cat: dev/chardev: Kein passendes Gerät bzw. keine passende Adresse gefunden
+cassini/home/peter/bo/2021ss/bs/20210430> lsmod | grep chardev
+cassini/home/peter/bo/2021ss/bs/20210430>
diff --git a/20210507/modules-6.txt b/20210507/modules-6.txt
new file mode 100644
index 0000000000000000000000000000000000000000..e96c84006288c46e2ff5ee3b397a81b4db94d374
--- /dev/null
+++ b/20210507/modules-6.txt
@@ -0,0 +1,40 @@
+cassini/home/peter/bo/2021ss/bs/20210430> sudo insmod chardev-1a.ko
+cassini/home/peter/bo/2021ss/bs/20210430> lsmod | grep chardev
+chardev_1a 16384 0
+cassini/home/peter/bo/2021ss/bs/20210430> cat dev/chardev
+I already told you 0 times Hello world!
+cassini/home/peter/bo/2021ss/bs/20210430> cat dev/chardev
+I already told you 1 times Hello world!
+cassini/home/peter/bo/2021ss/bs/20210430> echo "Dies ist ein Test." > dev/chardev
+cassini/home/peter/bo/2021ss/bs/20210430>
+
+
+Inhalt von /var/log/kern.log:
+
+May 7 12:57:21 cassini kernel: [1601195.178390] I was assigned major number 241. To talk to
+May 7 12:57:21 cassini kernel: [1601195.178391] the driver, create a dev file with
+May 7 12:57:21 cassini kernel: [1601195.178392] 'mknod /dev/chardev c 241 0'.
+May 7 12:57:21 cassini kernel: [1601195.178392] Try various minor numbers. Try to cat and echo to
+May 7 12:57:21 cassini kernel: [1601195.178392] the device file.
+May 7 12:57:21 cassini kernel: [1601195.178393] Remove the device file and module when done.
+May 7 12:57:40 cassini kernel: [1601214.177086] Got user data: Dies ist ein Test.
+May 7 12:57:40 cassini kernel: [1601214.177086] ss/bs/20210430
+May 7 12:57:40 cassini kernel: [1601214.177086] indow -P openmeetings https://www.cvh-server.de/vnc/ &
+May 7 12:57:40 cassini kernel: [1601214.177086] return
+May 7 12:57:40 cassini kernel: [1601214.177086] ;;
+May 7 12:57:40 cassini kernel: [1601214.177086] esac;
+May 7 12:57:40 cassini kernel: [1601214.177086] local complete_opt="--others --modified --directory --no-empty-directory";
+May 7 12:57:40 cassini kernel: [1601214.177086] if test -n "$(__git_find_on_cmdline "-u --update")"; then
+May 7 12:57:40 cassini kernel: [1601214.177086] complete_opt="--modified";
+May 7 12:57:40 cassini kernel: [1601214.177086] fi;
+May 7 12:57:40 cassini kernel: [1601214.177086] __git_complete_index_file "$complete_opt"
+May 7 12:57:40 cassini kernel: [1601214.177086] exclude=$OPTARG
+May 7 12:57:40 cassini kernel: [1601214.177086] ;;
+May 7 12:57:40 cassini kernel: [1601214.177086] p)
+May 7 12:57:40 cassini kernel: [1601214.177086] vprev=$OPTARG
+May 7 12:57:40 cassini kernel: [1601214.177086] ;;
+May 7 12:57:40 cassini kernel: [1601214.177086] w)
+May 7 12:57:40 cassini kernel: [1601214.177086] vwords=$OPTARG
+May 7 12:57:40 cassini kernel: [1601214.177086] ;;
+May 7 12:57:40 cassini kernel: [1601214.177086] esac;
+May 7 12:57:40 cassini kernel: [1601214.177086] done;
diff --git a/20210507/modules-7.txt b/20210507/modules-7.txt
new file mode 100644
index 0000000000000000000000000000000000000000..43d30622349766288b101f6a13e2748073e60e93
--- /dev/null
+++ b/20210507/modules-7.txt
@@ -0,0 +1,37 @@
+cassini/home/peter/bo/2021ss/bs/20210430> sudo insmod chardev-1b.ko
+cassini/home/peter/bo/2021ss/bs/20210430> echo "Dies ist ein Test." > dev/chardev
+cassini/home/peter/bo/2021ss/bs/20210430> sudo tail -22 /var/log/kern.log
+May 7 12:57:40 cassini kernel: [1601214.177086] if test -n "$(__git_find_on_cmdline "-u --update")"; then
+May 7 12:57:40 cassini kernel: [1601214.177086] complete_opt="--modified";
+May 7 12:57:40 cassini kernel: [1601214.177086] fi;
+May 7 12:57:40 cassini kernel: [1601214.177086] __git_complete_index_file "$complete_opt"
+May 7 12:57:40 cassini kernel: [1601214.177086] exclude=$OPTARG
+May 7 12:57:40 cassini kernel: [1601214.177086] ;;
+May 7 12:57:40 cassini kernel: [1601214.177086] p)
+May 7 12:57:40 cassini kernel: [1601214.177086] vprev=$OPTARG
+May 7 12:57:40 cassini kernel: [1601214.177086] ;;
+May 7 12:57:40 cassini kernel: [1601214.177086] w)
+May 7 12:57:40 cassini kernel: [1601214.177086] vwords=$OPTARG
+May 7 12:57:40 cassini kernel: [1601214.177086] ;;
+May 7 12:57:40 cassini kernel: [1601214.177086] esac;
+May 7 12:57:40 cassini kernel: [1601214.177086] done;
+May 7 13:07:49 cassini kernel: [1601823.599104] I was assigned major number 241. To talk to
+May 7 13:07:49 cassini kernel: [1601823.599106] the driver, create a dev file with
+May 7 13:07:49 cassini kernel: [1601823.599108] 'mknod /dev/chardev c 241 0'.
+May 7 13:07:49 cassini kernel: [1601823.599108] Try various minor numbers. Try to cat and echo to
+May 7 13:07:49 cassini kernel: [1601823.599109] the device file.
+May 7 13:07:49 cassini kernel: [1601823.599109] Remove the device file and module when done.
+May 7 13:07:58 cassini kernel: [1601832.651791] Got user data: Dies ist ein Test.
+May 7 13:07:58 cassini kernel: [1601832.651791] .
+cassini/home/peter/bo/2021ss/bs/20210430> tail chardev-1b.c
+ */
+static ssize_t
+device_write(struct file *filp, const char *buff, size_t len, loff_t * off)
+{
+ char b[len + 1];
+ strncpy (b, buff, len);
+ b[len] = 0;
+ printk(KERN_INFO "Got user data: %s.\n", b);
+ return len;
+}
+cassini/home/peter/bo/2021ss/bs/20210430>
diff --git a/20210507/os-layers-1.jpg b/20210507/os-layers-1.jpg
new file mode 120000
index 0000000000000000000000000000000000000000..6dc99e9e12dbc84e908c37974c7d528be014d587
--- /dev/null
+++ b/20210507/os-layers-1.jpg
@@ -0,0 +1 @@
+../common/os-layers-1.jpg
\ No newline at end of file
diff --git a/20210507/os-layers-2.jpg b/20210507/os-layers-2.jpg
new file mode 120000
index 0000000000000000000000000000000000000000..4da385ea396af0f9c7ed79b23a183a3b5618b445
--- /dev/null
+++ b/20210507/os-layers-2.jpg
@@ -0,0 +1 @@
+../common/os-layers-2.jpg
\ No newline at end of file
diff --git a/20210507/os-layers-3.jpg b/20210507/os-layers-3.jpg
new file mode 120000
index 0000000000000000000000000000000000000000..eaf5b599709e39d1c51dfdac28843c31b3fa971c
--- /dev/null
+++ b/20210507/os-layers-3.jpg
@@ -0,0 +1 @@
+../common/os-layers-3.jpg
\ No newline at end of file
diff --git a/20210507/os-layers-4.jpg b/20210507/os-layers-4.jpg
new file mode 120000
index 0000000000000000000000000000000000000000..efcbbd1827ff55f225fee0b77b8bfb5c6cff980c
--- /dev/null
+++ b/20210507/os-layers-4.jpg
@@ -0,0 +1 @@
+../common/os-layers-4.jpg
\ No newline at end of file
diff --git a/20210507/os-layers-5.jpg b/20210507/os-layers-5.jpg
new file mode 120000
index 0000000000000000000000000000000000000000..91cabe9241f19ece833cb22e8f16587153f246a2
--- /dev/null
+++ b/20210507/os-layers-5.jpg
@@ -0,0 +1 @@
+../common/os-layers-5.jpg
\ No newline at end of file
diff --git a/projekte.txt b/projekte.txt
index 21956a5cfdc5b8c74c6e2d2979f85cffe6dccd36..c76d4d7f25a9bb9cdf940f725af420435e794229 100644
--- a/projekte.txt
+++ b/projekte.txt
@@ -28,3 +28,4 @@
Bsp-Instanz aus Bochum (von dem dortigen Hackspace): https://virtuallab.das-labor.org/
Doku dazu: https://howto.rc3.world/workadventure.en.html
- Treiber für freies Smartphone
+ - Echtzeit-Kommunikation mit freiem Smartphone