1. Linux project no 1
address: http://www.csie.ncu.edu.tw/~hsufh/COURSES/FALL2008/linux_project1.html
now is 20081208 Mon: I try again to do
implementing system call
http://tldp.org/HOWTO/html_single/Implement-Sys-Call-Linux-2.6-i386/
and
rebuild kernel
http://www.cromwell-intl.com/unix/linux-kernel.html
I append today's date as the label, ie. 20081208
folder is in /usr/src/linux*-20081208
name of the new build is also wit *-20081208
I already expand my vmware disk vmdk with this command:
http://blogs.developerfusion.co.uk/blogs/thushan/archive/2007/04/16/2629.aspx
All files modified are backed up using this extension: *.nur
test file is in ~/system-call-examples/20081208/
-------
Old:
---------------
trying this:
http://tldp.org/HOWTO/html_single/Implement-Sys-Call-Linux-2.6-i386/
-- twice & not successfull:
rebuild kernel & install kernel give no error
compile test code (testmycall.c) gives the following errors:
Error code for the second trial:
---------------------------------
In file included from testmycall.c:7:
testmycall.h:9: error: expected declaration specifiers or ‘...’ before ‘mycall’
testmycall.h:9: error: expected declaration specifiers or ‘...’ before ‘i’
testmycall.c: In function ‘_syscall1’:
testmycall.c:11: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or
‘__attribute__’ before ‘{’ token

2. testmycall.h:9: error: parameter name omitted
testmycall.h:9: error: parameter name omitted
testmycall.c:15: error: expected ‘{’ at end of input
---------------------------------
command to capture out and error:
./cmd 1>out.txt 2>err.txt
I will try another steps from:
http://lwyy.eboler.com/2006/12/3/
How to build a kernel?
http://www.howtoforge.com/kernel_compilation_fedora
http://www.mjmwired.net/resources/mjm-kernel-fc4.html
Already done with Dung and successful:
http://www.cromwell-intl.com/unix/linux-kernel.html
Need to do:
Modify kernel
Compile kernel
Restart using new kernel
Add a new system call:
http://www.ibm.com/developerworks/library/l-system-calls/index.html
simplified system call with interrupt:

3. ========= IMPORTANT =============
Seems more practical resource is: (this is step by step instruction to create a new system call!)
http://tldp.org/HOWTO/html_single/Implement-Sys-Call-Linux-2.6-i386/ WORTH READING
[SHOULD BE READ FIRST!]
http://www.cmpe.boun.edu.tr/courses/cmpe322/fall2008/Tutorials/Kernel%20Compile%20and
%20SysCall%20Add%20(Ubuntu%208.04).pdf (Similar to above, but for UBUNTU!)
Detailed steps begin on page 4/6.
========= IMPORTANT =============
http://www.linuxjournal.com/article/3326 --> THIS IS like previous resource, and there IS steps
to compile kernel! [WORTH READING]
But it is obsolete! December 1st, 1999 You will read that we should use a floppy!
Obsolete: http://www.csee.umbc.edu/courses/undergraduate/CMSC421/fall02/burt/projects/howt
o_add_systemcall.html
http://www.csee.umbc.edu/courses/undergraduate/CMSC421/fall02/burt/projects/howto_build_ke
rnel.html
Similar project with detailed instructions:
http://www.cs.duke.edu/courses/spring05/cps210/Lab1.html

4. http://syn.cs.pdx.edu/~jsnow/ta/timer.html (Not checked)
Other links to check include:
http://lwn.net/Articles/281965/ NOT WORTH READING
Comment:
.... this is new : May 14, 2008! but let me read first. And unfortunately, this is not a basic article to
read!
Part 1
First we edit the following program (with vim):
#include <stdio.h>
main()
{
while(1)
;
}
save the code as orchid.c
then we compile it with gcc
gcc orchit c -o orchid
then we run it in the background:
./orchid &
(to create another background process, just repeat that command. We need to make 20
background processes.)
to view the process ID we use command
ps
After we found PID, we can see the memory location with this command
(http://www.cyberciti.biz/tips/howto-find-memory-used-by-program.html )
$ pmap PID
$ pmap 3724
And now we will create a C program to find the address of each task_struct data generated by
each our orchid program.
Resources helping us in doing this include:

5. http://www.informit.com/articles/article.aspx?p=370047
http://linuxgazette.net/133/saha.html
but how to print each address pointing to task_struct data. This may help us:
http://stackoverflow.com/questions/197757/printing-pointers-in-c
We now hope those above will solve our fist part of project 1.
We have unsolved problem when compiling this code:
We try to compile this simple C code (Cobaba.c):
#include </usr/include/linux/kernel.h>
#include </usr/include/linux/sched.h>
#include </usr/include/sepol/module.h>
int main()
{
struct task_struct *task;
for_each_process (task)
{
printk("%s[%d]n", task->comm, task->pid);
//printf("hello");
}
return 0;
}
We found compile errors like this:
Cobaba.c: In function ‘main’:
Cobaba.c:9: error: expected ‘;’ before ‘{’ token
What's wrong with our code?
But it seems that we get the answer here:

6. http://www.linuxquestions.org/linux/articles/Technical/Linux_Kernel_Thread
Part 2
Now we will go to explore and understand second part of project 1. (although part 1 have not
been solved yet)
First question of part 2:
After the above experiment, terminate the execution of the above 20 processes, and then
execute orchid in the background. Then list (1) the PID of the group leader of the process that executes
the above orchid and (2) the PID of the group leader of the shell process that creates the process which
executes the above orchid.
Answer:
To terminate 20 process from part 1, we use kill command.
$ kill PID
How do we know the PID of the process(es) that we want to kill? Use ps command as above.
After we kill all orchid processes, we start one orchid process in the background, then list the PID of
the group leader of the process. What does group leader mean? Does it mean parent of the process?
To list PID