Literature and documentation

[nixawk]

Literature and documentation

Operating Systems

• Andrew S. Tanenbaum, Modern Operating Systems, Prentice Hall, 1992.

The Unix OS

• John Lions, Lions' Commentary on UNIX 6th Edition with Source Code, Peer-to-Peer Communications, 1996, published by Annabooks, ISBN 1-57398-013-7.
• Maurice J. Bach, Design of the Unix Operating System, Prentice Hall, 1986.
• Uresh Vahalia, Unix Internals: The New Frontiers, Prentice Hall, 1995.
• Marshall Kirk McKusick, Keith Bostic, Michael J. Karels & John S. Quarterman, The Design and Implementation of the 4.4 BSD Operating System, Addison-Wesley, 1996.

Unix programming

• W. Richard Stevens, Advanced Programming in the UNIX Environment, Addison-Wesley, 1994.

The Linux kernel

• David Rusling, The Linux Kernel. Online version [On Linux 2.0.]
• Daniel P. Bovet & Marco Cesati, Understanding the Linux kernel, O'Reilly, 2001. [On Linux 2.2.]
• Daniel P. Bovet & Marco Cesati, Understanding the Linux kernel, 2nd edition, O'Reilly, 2003. [On Linux 2.4.]
• Daniel P. Bovet & Marco Cesati, Understanding the Linux kernel, 3rd edition, O'Reilly, 2005. [On Linux 2.6.]
• Alessandro Rubini, Linux device drivers, O'Reilly, 1998.
• Alessandro Rubini & Jonathan Corbet, Linux device drivers 2nd ed., O'Reilly, 2001. Online version
• Jonathan Corbet, Alessandro Rubini & Greg Kroah-Hartman, Linux device drivers 3rd ed., O'Reilly, 2005. Online version
• M. Beck, H. Böhme, M. Dziadzka, U. Kunitz, R. Magnus, C. Schröter & D. Verworner, Linux kernel programming 3rd ed., Addison Wesley, 2002.
• R. Card, E. Dumas & F. Mevel, The Linux Kernel Book, John Wiley and Sons, 1998.
• David Mosberger & Stéphane Eranian, IA-64 Linux kernel, HP / Prentice Hall, 2002.
• Robert Love, Linux Kernel Development, Developer's library, 2003. ISBN 0-672-32512-8 ad

On the web one can find an enormous amount of information. Use your favorite search engine.

References

• https://www.win.tue.nl/~aeb/linux/lk/lk-1.html#ss1.1

[nixawk]

demo-module.c

/*
 * demo-module.c
 *
 * Compile with Makefile
 */

#include <linux/init.h>
#include <linux/module.h>

static int __init demo_init(void) {
        printk("initializing..\n");
	printk("hello kernel module.\n");
        return 0;
}

static void __exit demo_exit(void) {
        printk("goodbye!\n");
}

module_init(demo_init);
module_exit(demo_exit);
MODULE_LICENSE("GPL");

Makefile

ifneq ($(KERNELRELEASE),)
	# call from kernel build system
	lifo-objs := main.o
	obj-m   := demo-module.o
else
	KERNELDIR ?= /lib/modules/$(shell uname -r)/build
	PWD       := $(shell pwd)
modules:
	echo $(MAKE) -C $(KERNELDIR) M=$(PWD) LDDINC=$(PWD)/../include modules
	$(MAKE) -C $(KERNELDIR) M=$(PWD) LDDINC=$(PWD)/../include modules
endif

clean:  
	rm -rf *.o *~ core .depend *.mod.o .*.cmd *.ko *.mod.c .tmp_versions *.markers *.symvers modules.order

depend .depend dep:
	$(CC) $(CFLAGS) -M *.c > .depend

ifeq (.depend,$(wildcard .depend))
	include .depend
endif

Compile

root@lab:~/kernel# make
echo make -C /lib/modules/4.14.0-kali3-amd64/build M=/root/kernel LDDINC=/root/kernel/../include modules
make -C /lib/modules/4.14.0-kali3-amd64/build M=/root/kernel LDDINC=/root/kernel/../include modules
make -C /lib/modules/4.14.0-kali3-amd64/build M=/root/kernel LDDINC=/root/kernel/../include modules
make[1]: Entering directory '/usr/src/linux-headers-4.14.0-kali3-amd64'
  CC [M]  /root/kernel/demo-module.o
  Building modules, stage 2.
  MODPOST 1 modules
  CC      /root/kernel/demo-module.mod.o
  LD [M]  /root/kernel/demo-module.ko
make[1]: Leaving directory '/usr/src/linux-headers-4.14.0-kali3-amd64'

root@lab:~/kernel# tail -f /var/log/messages

Apr 26 00:49:38 lab kernel: [ 2439.064133] initializing..
Apr 26 00:49:38 lab kernel: [ 2439.064134] hello kernel module.
Apr 26 00:49:53 lab kernel: [ 2454.486565] goodbye!

root@lab:~/kernel# insmod demo-module.ko 
root@lab:~/kernel# rmmod demo_module 

• https://www.win.tue.nl/~aeb/linux/lk/lk-2.html

[nixawk]

Magic SysRequest

When so configured, there is one more keyboard mechanism. Build the kernel with CONFIG_MAGIC_SYSRQ enabled. In some kernel versions you then have an active Magic SysRequest key, but in other kernels you first have to do

echo 1 > /proc/sys/kernel/sysrq

to activate this key. A command is given by pressing three keys simultaneously: Alt-SysRq-X, where X is the command letter. (On a serial console one gives a Break, followed by the command letter.)

Since Linux 2.4.21/2.5.66 it is also possible to do

echo X > /proc/sysrq-trigger

with the same effect as the keystroke.

Command letters

• r Set kbd mode to XLATE (not RAW)
• k SAK (Secure Attention Key)
• b Immediate reboot, no umount, no sync
• o Shut Off system
• s Sync
• u Remount all filesystems read-only
• p Print registers on console, like Show_Registers above.
• t Print tasks on console, like Show_State above.
• m Print memory info on console, like Show_Memory above.
• 0-9 Set console loglevel
• e Send every process SIGTERM
• i Send every process SIGKILL

One should make sure that this facility is always switched off in a production environment.

---

# echo 1 > /proc/sys/kernel/sysrq
# echo m > /proc/sysrq-trigger
# less /var/log/messages