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The criu utility dumps the state of processes/containers into a set of image files. This article describes the format of them.
 
The criu utility dumps the state of processes/containers into a set of image files. This article describes the format of them.
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== General format description ==
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== Types of image files ==
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CRIU images can be in one of formats
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* crtools specific images in google protocol buffer format (PB format)
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* crtools specific images with binary data in it
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* image files in 3rd party format
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== crtools-specific format description ==
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Most of the crtools image files begin with 32-bit magic cookie followed by zero or more entries of the same type (not size!). Most of the entries are encoded in the Google Protocol Buffers format and each is preceded with 32-bit entry size value (not including this 32-bit value itself). Optionally each entry may be followed by extra payload which depends on the entry type.
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All crtools-specific image files begin with 32-bit magic cookie. Images in PB format are followed by zero or more entries of the same type (not size!), each entry is preceded with 32-bit entry size value (not including this 32-bit value itself). Optionally each entry may be followed by extra payload which depends on the entry type.
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IOW image files look like
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IOW protocol-buffers image files look like
    
<pre>
 
<pre>
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The amount of entries in a image file depends on the type of file.
 
The amount of entries in a image file depends on the type of file.
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== Types of image files ==
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== Types of image files with PB data  ==
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Images encoded with ProtocolBuffers can be one of
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Such images can be one of
    
; Array image files
 
; Array image files
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  |}
 
  |}
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There are, however, images which are not in ProtocolBuffers.
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== Images with binary crtools data ==
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These are
    
; Memory dumps
 
; Memory dumps