HACKING.en

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   Adding extra software to TCOS initramfs

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 TCOS is a set of scripts that copies binaries and 
 libraries in a boot image file. It is posible to
 add more utilities as they are needed.

 Use /etc/tcos/hacking/template as a template
 
 HOW-TO add specific applications to the generated 
 image:

 Add display (image viewer => ImageMagick)

 Create a file in /etc/tcos/hacking/ containing this:

 ####### /etc/tcos/hacking/display ##############
 # TCOS script for display command
 
 cpifexists /usr/bin/display /usr/bin

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 Helpers that can be used:

 * cpifexits [BINARY] [PATH_DESTINATION]

 Ayudantes que podemos usar:

 * cpifexits [BINARY] [PATH_DESTINATION]

    It copies a BINARY designated by its full path 
    in PATH_DESTINATION inside the initramfs 

    This function also copies any  dependent library.
    
    Example:
      cpifexists /sbin/fdisk /sbin/

   Internally it runs:
   $ ldd /sbin/fdisk
        linux-gate.so.1 =>  (0xffffe000)
        libc.so.6 => /lib/tls/libc.so.6 (0xb7e3e000)
        /lib/ld-linux.so.2 (0xb7f8f000)

  And the linked libraries are copied.
 NOTE: It will try NOT copying any library related to /lib/tls/

 Regular files can be copied too:
      cpifexists /etc/hosts.allow /etc/
 

 * copydir [DIR]  [PATH_DESTINATION]
    
    It copies a whole directory in the initramfs file,
    being equivalent to run cp -ra DIR $INITRAMFS/$DESTINATION
    
    Example:
       copydir /etc/dropbear/ /etc/

 * stat_before

     It calculates the initramfs file's size for state_after 
     function 

 * stat_after "TEXT"

    It calculates the difference between the current initramfs 
    file's size and the one state_before calculated and prints
    that difference on screen.

    Full example:

       stat_before
       cpifexists /usr/bin/display /usr/bin/
       stat_after "ImageMagick display"

     This copies the BINARY (and linked libraries) in the 
     initramfs and calculates the added size, printing on
     screen:

     => Package ImageMagick display got XXX Kb.