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SIOL - Simple IO Layer

doc/siol.md

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SIOL - Simple IO Layer

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+==================+
| Write-Mask       |
+==================+
| Buffer           | <--- maybe this could be deprecated, I see no usecase for the buffer
+==================+
| Cache (V)        |
+==================+      +========================+
| Maps             | <=== | Sections (transformed) |
+==================+      +========================+
| Descs            |
|      +===========+
|      | Cache (P) |
+======+===========+
| Plugin           |
+==================+

Maps

Every map has a mapid which is a unique identifier. Code from the outside of RIO shall use this id instead of a pointer. This may cost performance, but pointers can hurt you.

Mapping information in the map:

  • from
  • to
  • delta
  • fd

Section Transformation

At the moment there are 3 different transformation-targets:

  • Hexeditor
  • Analysis
  • Emulation

Mapping information in the section:

  • addr
  • size
  • vaddr
  • vsize
  • fd

A section can be related to 2 maps:

  • memmap
  • filemap

Hexeditor-Transformation:

  • check if addr != vaddr, if so continue
  • create a map with the size of min (size, vsize), that maps the to fd corresponding desc to vaddr, starting at addr
  • filemap is set to the id of the map
  • memmap stays 0

Analysis-Transformation:

  • when vsize <= size perform Hexeditor-Transformation, and you're done
  • create a map with the size of size, that the to fd corresponding vaddr, starting at addr
  • filemap is set to the id of the map
  • open a new desc, using the null-plugin, with the size of vsize - size
  • create another map with the size of vsize - size, that maps the new desc to vaddr + size, starting at 0x0
  • memmap is set to the id of the second map

Emulation-Transformation:

  • when the section does not allow write-access perform Analysis-Transformation, and you're done
  • open a new desc with write-permissions, using the malloc-plugin, with the size of vsize
  • copy min (size, vsize) bytes fram the desc, that fd refers to, starting at addr, to the new desc, starting at 0x0
  • create a map with the size of vsize, that maps the new desc to vaddr, starting at 0x0