Fedora 28 : Create a ISO image with stage2 and kernel ELF .

The tutorial for today solves the problem of creating an ISO image.
This image can be run and test with QEMU tool emulator like any ISO CDROM image.
You can build your kernel with any assembler and use this steps to test it.
I used the FASM assembly tool. Into my fasm folder I create these folders:

[mythcat@desk fasm]$ mkdir -p iso/boot/grub

You need a stage2 file known like: stage2_eltorito.
This file uses the El Torito is a specification for bootable CD using BIOS functions.
The GRUB supports the no emulation mode in the El Torito specification.
El Torito file booting begins by the Boot Record of the ISO 9660 filesystem at block address 0x11.
You can get this file from your Linux distro of you can find installed into old GRUB.
Put this file into grub folder:

[mythcat@desk fasm] cp /usr/lib/grub/i386-pc/stage2_eltorito  iso/boot/grub/

Use fasm tool with your kernel and use this commands to create the ISO file:

[mythcat@desk fasm]$ ./fasm kernel.asm 
flat assembler  version 1.73.04  (16384 kilobytes memory)
2 passes, 16756 bytes.
[mythcat@desk fasm]$ cp kernel.o iso/boot/kernel.k
[mythcat@desk fasm]$ cat > iso/boot/grub/menu.lst << EOF
> default 0
> timeout 1
> title fasm multiboot
> kernel /boot/kernel.k
> EOF
[mythcat@desk fasm]$ genisoimage -R -b boot/grub/stage2_eltorito -no-emul-boot -boot-load-size 4
 -boot-info-table -o mykernel.iso iso

I: -input-charset not specified, using utf-8 (detected in locale settings)
Size of boot image is 4 sectors -> No emulation
Total translation table size: 2048
Total rockridge attributes bytes: 920
Total directory bytes: 4096
Path table size(bytes): 34
Max brk space used 24000
241 extents written (0 MB)

Now you can test the result:

[mythcat@desk fasm]$ qemu-system-i386 -cdrom mykernel.iso

This is result of my kernel:

Fedora 28 : The edb debugger.

Today I tested one debug for assembly language.
I used FASM programming language because is very flexible.
The main goal was to find a good debugger and I try the edb debugger.
If you try to use the Fedora dnf tool then you get an older version of this debugger.

[root@desk mythcat]# dnf install edb.x86_64

Because this package is old I try to compile it from source code from github.
Let's see this steps:

[mythcat@desk fasm]$ git clone --recursive https://github.com/eteran/edb-debugger.git

Cloning into 'edb-debugger'...
remote: Enumerating objects: 192, done.
remote: Counting objects: 100% (192/192), done.
...
[root@desk mythcat]# dnf install git make qt5-devel gcc gcc-c++ boost-devel cmake capstone-devel
...
[mythcat@desk edb-debugger]$ mkdir build
[mythcat@desk edb-debugger]$ cd build

[mythcat@desk build]$ cmake ..
-- Boost version: 1.66.0
-- Checking for module 'capstone>=3.0.4'
--   Found capstone, version 3.0.5
-- Checking for module 'libgvc>=2.38.0'
--   Package 'libgvc', required by 'virtual:world', not found
-- Checking for module 'double-conversion'
-- Looking for C++ include double-conversion/double-conversion.h
-- Looking for C++ include double-conversion/double-conversion.h - not found
CMake Warning at CMakeLists.txt:56 (message):
  libdouble-conversion header wasn't found.  32- and 64-bit floating-point
  values will be showed with max_digits10 digits of precision instead of
  shortest representation.


-- Checking for module 'gdtoa-desktop'
--   Package 'gdtoa-desktop', required by 'virtual:world', not found
CMake Warning at CMakeLists.txt:113 (message):
  gdtoa-desktop package wasn't found.  80-bit floating-point values will be
  showed with max_digits10 digits of precision instead of shortest
  representation.


-- Configuring done
-- Generating done
-- Build files have been written to: /home/mythcat/fasm/edb-debugger/build

[mythcat@desk build]$ make
Scanning dependencies of target edb_autogen
...

You can see the executable file named edb into the build folder.
Just run it and the debugger starts.
Into the next image you can see a simple executable run into this debugger:

Fedora 27 : The strace tool for debug.

Today I test a great tool named strace from here.
This tool will help you with diagnostic, debugging and monitor between processes and the Linux kernel.

For example you can test this tool with ls command:
- to display only a specific system call, use the strace -e option as shown below.

$ strace -e open ls > /dev/null

- the result of this will come with all infos about count time, calls, and errors for each system call.

$ strace -c ls > /dev/null

- save the trace execution to a file:

$ strace -o output.txt ls

- display and save the strace for a given process id:

$ strace -p 1725 -o process_id_trace.txt

You can see more examples on the official webpage.

gDEBugger - FREE or NOT ?

A very popular OpenGL debugger is now available for FREE?
On official site we saw:
Order
gDEBugger is not available for purchasing for the time being.
We plan to release a new and **FREE** gDEBugger version for Windows, Linux and Mac OS X. This version will be available for download by the end of 2010.
Please make sure to check our website for this version in the near future.
Until the free version will be released, please find below a temporary license file that will enable you to use the current gDEBugger version for free immediately.
Now is the end of 2010, but is not free.
What is gDEBugger
Named gDEBugger is an advanced OpenGL Debugger, Profiler and Graphic Memory Analyzer.
This 3D software saves you debugging time and helps you boost application performance.
We can download it from :here.
I searched my computer the lib libstdc++, see below :

# yum search libstdc++
Loaded plugins: langpacks, presto, refresh-packagekit
Adding en_US to language list
============================== Matched: libstdc++ ==============================
compat-libstdc++-296.i686 : Compatibility 2.96-RH standard C++ libraries
compat-libstdc++-33.i686 : Compatibility standard C++ libraries
libstdc++.i686 : GNU Standard C++ Library
libstdc++-devel.i686 : Header files and libraries for C++ development
libstdc++-docs.i686 : Documentation for the GNU standard C++ library
libstdc++-static.i686 : Static libraries for the GNU standard C++ library

The archive named gDEBugger57-i386-cpp3.tar.gz has 13Mb.
Then I use commands :

$gzip -dc gDEBugger57-i386-cpp3.tar.gz | tar xf -
$ cd gDEBugger57-i386-cpp3
$ su 
# yum install compat-libstdc++-33.i686 

The gDEBugger run well under fedora 14 , but is free only 7 days. See below: