[PATCH] [BZ #18433] Check file access/existence before forking.

Szabolcs Nagy szabolcs.nagy@arm.com
Fri Sep 18 15:03:00 GMT 2015


On 18/09/15 15:44, Carlos O'Donell wrote:
> Note that it is possible to use vfork in certain conditions,
> and we do in glibc. So one should not entirely dismiss vfork,
> but that's slightly off topic.

are you sure?

i think all use of vfork is invalid c: the compiler can
spill registers on the stack then in the child clobber
them, then after vfork returns in the parent the
clobbered registers are restored breaking the expectations
of the compiler. (this can break independently of how
the c code around vfork looks like).

i think you have to know the compiler internals or use
some language extension to make it valid.



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