[Buildroot] [PATCH] pkgconf: make wrapper relocatable

Peter Korsgaard peter at korsgaard.com
Wed Mar 9 15:06:48 UTC 2016


>>>>> "Arnout" == Arnout Vandecappelle <arnout at mind.be> writes:

Hi,

>> well, if executed throyh a shell it will - But if I write code to call
 >> execve I get to chose what argv[0] should be.

 >  Read the section "Interpreter scripts" of execve(2). argv[0] is discarded.

Ahh yes, for a script this would be true because of the shebang handling
in the kernel, but it is not true for normal ELF binaries.

>> That's another reason. If somebody does a symlink to our wrapper, then
 >> $0 will contain the full path to the link, not to the wrapper
 >> itself.

 >  So we need to readlink it first.

Yes, or read /proc/self/exec.

 >> If somebody does a hardlink, /proc/self/exe won't even fix it for you -
 >> But that is probably quite unlikely.

 >  For the hardlink case there is no solution.

Indeed.

-- 
Venlig hilsen,
Peter Korsgaard 


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