on linux open supports() O_CLOEXEC. add test case for this in meson
build and ifdef. this rolls 3 syscalls into 1 as we were doing open,
then fnctl to get and fcntl to set flags.
less syscalls is a good thing as syscalls are not cheap on some
architectures or systems. I've seen a syscall on 1 system take 2-3x
as long as another and another syscall in the same 2 system
comparison take 10x as long. depending on the syscall you may only
have a budget of something like 5000 syscalls "per frame" (60fps)
before you spend all of your frame time just in syscalls not
doing any processing, so we should keep these down if possible
and that is what this does.
restrict mapping /dev/zero to only eina files having a sigbus
reported. the mmap was before all our file access used eina_file i
think thus the raw mmap of it. now walk all eina files and find the
candidate and only then if it exists flag is as having a faulty i/o
backing and map the zerto pages then return, otherwise call abort.
more restricted mapping and perhaps a fix for not trapping non-efl
issues.
@fix
@fix
this fixes the eina mmap safety handler to only handle what comes
from actual i/o errors (not actual corrupt/hw memory faults or invalid
objects), and if it's not a sigbus eina mmap should handle then pass
it onto the previous handler before eina mmap took over.
Signal are not a portable way to detect memory mapped file corruption.
So let's disable it for system without signal and later find a way to
detect it on other system.
Carsten Haitzler
Cedric BAIL
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Lucas De Marchi
Vincent Torri