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59 lines
3.0 KiB
ReStructuredText
59 lines
3.0 KiB
ReStructuredText
The macaw library implements architecture-independent binary code
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discovery. Support for specific architectures is provided by
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implementing the semantics of that architecture. The library is
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written in terms of an abstract interface to memory, for which an ELF
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backend is provided (via the elf-edit_ library). The basic code
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discovery is based on a variant of Value Set Analysis (VSA).
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The most important user-facing abstractions are:
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* The ``Memory`` type, defined in ``Data.Macaw.Memory``, which provides an abstract interface to an address space containing both code and data.
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* The ``memoryForElfSegments`` function is a useful helper to produce a ``Memory`` from an ELF file.
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* The ``cfgFromAddrs`` function, defined in ``Data.Macaw.Discovery``, which performs code discovery on a ``Memory`` given some initial parameters (semantics to use via ``ArchitectureInfo`` and some entry points.
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* The ``DiscoveryInfo`` type, which is the result of ``cfgFromAddrs``; it contains a collection of ``DiscoveryFunInfo`` records, each of which represents a discovered function. Every basic block is assigned to at least one function.
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Architecture-specific code goes into separate libraries. X86-specific code is in the macaw-x86 repo.
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An abbreviated example of using macaw on an ELF file looks like::
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import qualified Data.Map as M
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import qualified Data.ElfEdit as E
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import qualified Data.Parameterized.Some as PU
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import qualified Data.Macaw.Architecture.Info as AI
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import qualified Data.Macaw.Memory as MM
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import qualified Data.Macaw.Memory.ElfLoader as MM
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import qualified Data.Macaw.Discovery as MD
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import qualified Data.Macaw.Discovery.Info as MD
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discoverCode :: E.Elf Word64 -> AI.ArchitectureInfo X86_64 -> (forall ids . MD.DiscoveryInfo X86_64 ids -> a) -> a
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discoverCode elf archInfo k =
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withMemory MM.Addr64 elf $ \mem ->
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let Just entryPoint = MM.absoluteAddrSegment mem (fromIntegral (E.elfEntry elf))
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in case MD.cfgFromAddrs archInfo mem M.empty [entryPoint] [] of
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PU.Some di -> k di
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withMemory :: forall w m a
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. (MM.MemWidth w, Integral (E.ElfWordType w))
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=> MM.AddrWidthRepr w
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-> E.Elf (E.ElfWordType w)
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-> (MM.Memory w -> m a)
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-> m a
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withMemory relaWidth e k =
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case MM.memoryForElfSegments relaWidth e of
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Left err -> error (show err)
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Right (_sim, mem) -> k mem
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In the callback, the ``DiscoveryInfo`` can be analyzed as desired.
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Implementing support for an architecture is more involved and requires implementing an ``ArchitectureInfo``, which is defined in ``Data.Macaw.Architecture.Info``. This structure contains architecture-specific information like:
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* The pointer width
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* A disassembler from bytes to abstract instructions
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* ABI information regarding registers and calling conventions
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* A transfer function for architecture-specific features not represented in the common IR
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.. _elf-edit: https://github.com/GaloisInc/elf-edit
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.. _flexdis86: https://github.com/GaloisInc/flexdis86
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