Developers

From CGSecurity

Contents 1 Using Git to get latest source code 2 Download source code 3 Adding a new file format to PhotoRec 4 qphotorec: PhotoRec with a Qt4 GUI

Using Git to get latest source code

Git is a modern source code manager

• Git article from Wikipedia
• Git Version Control System web site
• Git tutorial

http://git.cgsecurity.org/testdisk.git is a Git repository to track TestDisk & PhotoRec source code, you can browse it using http://git.cgsecurity.org/cgit/testdisk/

Install git using

• yum install git for Fedora, RedHat, Centos
• sudo apt-get install git-core for Debian, Ubuntu

Configure your local settings

$ git config --global user.name "Your Name"
$ git config --global user.email "Your Email"

Clone the current source code

$ git clone http://git.cgsecurity.org/testdisk.git

Compile TestDisk & PhotoRec

$ cd testdisk
$ mkdir config
$ aclocal -I config
$ autoheader -W all
$ autoconf -W all
$ automake --gnits --add-missing --copy
$ ./configure
$ make

Read TestDisk Compilation if you have problems to compile TestDisk & PhotoRec

It's time to make your own modifications and submit the patch

$ (edit files)
$ git add (files)
$ git commit -a
$ git format-patch origin/master
$ ls *.patch

Download source code

If you have been unable to install git, download a snapshot of TestDisk & PhotoRec latest source code. Get the beta version, the Work-In-Progress (WIP) one.

Adding a new file format to PhotoRec

The first step is to check if PhotoRec already identify the file. Run fidentify sample_file. If the file is identified with an incorrect extension, check if there is way to differentiate this file from files having the extension that has been found. If fidentify reports the format as unknown, you have found a candidate for inclusion.

If the file format specifications aren't available, compare several samples to identify constant fields. In example, PhotoRec identifies a JPEG file when a block begins with:

• 0xff,0xd8,0xff,0xe0
• 0xff,0xd8,0xff,0xe1
• or 0xff,0xd8,0xff,0xfe

To add a new file format to PhotoRec,

• edit src/file_list.c to add

  extern const file_hint_t file_hint_<EXTENSION>;

• and in list_file_enable[]

  { .enable=0, .file_hint=&file_hint_<EXTENSION> },

• edit src/Makefile.am to modify file_C definition, add

       file_<EXTENSION>.c

• If there is a header file, add it to file_H definition
• Create a file name src/file_<EXTENSION>.c.
• Register the various MAGIC header in register_header_check_EXTENSION()

In this example, file_check_EXTENSION() is used to check for a footer.

Check

• src/file_bmp.c for an example where the filesize is stored in the header.
• src/file_bac.c, src/file_mp3.c, src/file_m2ts.c, src/file_mov.c for file format using streaming
• src/file_gz.c, src/file_d2s.c, src/file_r3d.c for example where the file name is found in the header
• src/file_doc.c, src/file_exe.c where the file name may be found in the file itself
• src/file_doc.c, src/file_fits.c, src/file_jpg.c, src/file_tiff.c: date/time is extracted from the file

qphotorec: PhotoRec with a Qt4 GUI

Enable QPhotoRec compilation:

./configure --enable-qt && make

qphotorec isn't yet usable but you are welcome to work on it ;-)