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Added ELFObjectFileBase::checkMagic() for checking ELF magic word.
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Authored by vzakhari on Jun 2 2021, 11:43 AM.

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Summary

Added new method to ELFObjectFileBase to check whether the ELF image used to construct it is actually an ELF image (i.e. it has ELF magic word).

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Event Timeline

vzakhari requested review of this revision.Jun 2 2021, 11:43 AM
vzakhari created this revision.
Herald added a project: Restricted Project. · View Herald TranscriptJun 2 2021, 11:43 AM

git-clang-format HEAD^ may be useful for reformatting the already changed parts. LGTM, @jhenderson?

vzakhari updated this revision to Diff 349923.Jun 4 2021, 11:08 AM

We have lib/BinaryFormat/Magic.cpp. Do we need the ELF specific API?

We have lib/BinaryFormat/Magic.cpp. Do we need the ELF specific API?

Thanks! I was not aware of this code. How about adding something like static inline is_any_elf(file_magic) method in Magic.h? If you agree, then I will abandon this change-set and add the new method in D103545.

We have lib/BinaryFormat/Magic.cpp. Do we need the ELF specific API?

Thanks! I was not aware of this code. How about adding something like static inline is_any_elf(file_magic) method in Magic.h? If you agree, then I will abandon this change-set and add the new method in D103545.

I'm assuming this would be to avoid having to write something like if (objectType == elf || objectType == elf_relocatable || /*all the other elf_* types*/ ...) (or an equivalent switch statement)? Is this something you'd use in more than one place within your code?

We have lib/BinaryFormat/Magic.cpp. Do we need the ELF specific API?

Thanks! I was not aware of this code. How about adding something like static inline is_any_elf(file_magic) method in Magic.h? If you agree, then I will abandon this change-set and add the new method in D103545.

I'm assuming this would be to avoid having to write something like if (objectType == elf || objectType == elf_relocatable || /*all the other elf_* types*/ ...) (or an equivalent switch statement)? Is this something you'd use in more than one place within your code?

Exactly! I could add the same helper in the plugin code, but I'd rather keep it close to the file_magic enum definition. Do you suggest adding it in the plugin code?

It is rare that an application can process all of elf_relocatable, elf_executable, and elf_shared_object. llvm-objcopy is such a tool, but most others either only handle elf_relocatable or elf_executable+elf_shared_object.

vzakhari abandoned this revision.Jun 7 2021, 3:37 PM

Implemented using lib/BinaryFormat/Magic.cpp