[llvm-dev] DYLD implicit interposition

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[llvm-dev] DYLD implicit interposition

ORiordan, Martin via llvm-dev
From reading the ASAN diffs it seems implicit interposing is the ability to use dyld interposition without requiring DYLD_INSERT_LIBRARIES i.e. implicit interposing works by linking to the dylib that contains the interposers. Previously ASAN runtime would re-exec the program with DYLD_INSERT_LIBRARIES and this is no longer required with implicit interposing.

On 18/06/2017, at 7:00 AM, via llvm-dev <[hidden email]> wrote:

>> You could use implicit interposing. This is a feature add so that ASAN binaries can avoid the the whole re-exec with DYLD_INSERT_LIBRARIES issue. It is not guaranteed to be stable, but in practice it is probably the most stable option short of using a hypervisor. The way it works:
>
> Was is really added for ASAN ? I remember using dyld_interpose for a long time. It was already described in the Amit Singh edition of Mac OS X Internal book (which is older than clang). Or we are not talking about the same interpose ?
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Re: [llvm-dev] DYLD implicit interposition

ORiordan, Martin via llvm-dev
Thanks for the pointer. I missed the part about ‘implicit’. This is a great addition.

> Le 18 juin 2017 à 06:12, Michael Clark via llvm-dev <[hidden email]> a écrit :
>
> From reading the ASAN diffs it seems implicit interposing is the ability to use dyld interposition without requiring DYLD_INSERT_LIBRARIES i.e. implicit interposing works by linking to the dylib that contains the interposers. Previously ASAN runtime would re-exec the program with DYLD_INSERT_LIBRARIES and this is no longer required with implicit interposing.
>
> On 18/06/2017, at 7:00 AM, via llvm-dev <[hidden email]> wrote:
>
>>> You could use implicit interposing. This is a feature add so that ASAN binaries can avoid the the whole re-exec with DYLD_INSERT_LIBRARIES issue. It is not guaranteed to be stable, but in practice it is probably the most stable option short of using a hypervisor. The way it works:
>>
>> Was is really added for ASAN ? I remember using dyld_interpose for a long time. It was already described in the Amit Singh edition of Mac OS X Internal book (which is older than clang). Or we are not talking about the same interpose ?
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> LLVM Developers mailing list
> [hidden email]
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

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