we assume the fallback will be rare, so now we
make the mix static and keep xoring it, on the
theory that the number of failures on urandom
will be random, and tthat the fallback may only
apply once or twice in thousands of calls.
the time jitter is adjusted; rather than judge
the difference between two points close to each
other in time, we judge tthe randomness in
difference of time elapsed. this mitigates fast
CPUs being very fast and introducing rounding
errors, and also improves performonce on much
slower CPUs
Signed-off-by: Leah Rowe <leah@libreboot.org>
i was being cute earlier, but the rewrite
defeats the purpose of atomic file handling
in nvmutil, by not actually renaming! it was
more like, doing an actual copy, which meant
that corruption is likely during power loss
i've commented the code because i may
use it in a library in the future.
Signed-off-by: Leah Rowe <leah@libreboot.org>
this improves reliability, making it more
likely that data actually gets synced,
since fsync can return -1 with EINTR,
indicating that a re-try should be
attempted.
Signed-off-by: Leah Rowe <leah@libreboot.org>
arandom probably isn't available on super old obsd right??????
rather, unveil isn't. on systems that have arandom
yet we should not unveil something that may not
exist on modern systems
just don't unveil arandom, and don't check arandom
if unveil is enabled
Signed-off-by: Leah Rowe <leah@libreboot.org>
some systems may not even have it
works with /dev/fd (bsd/mac etc)
works with linux (/proc/self/fd)
and falls back on super old systems
that have neither
Signed-off-by: Leah Rowe <leah@libreboot.org>
settting it to -Werror is wrong, should set
it not -Werror.
however, put the WERROR variable in the make
command. that way, i could test with
make WERROR=-Werror
Signed-off-by: Leah Rowe <leah@libreboot.org>
try a few more times until success
explicitly return EEXIST when needed
we try multiple times and check more
thoroughly if a file exists, thus
reducing the risk of race conditions
Signed-off-by: Leah Rowe <leah@libreboot.org>
not portable. some old systems don't have it,
or handle it very poorly
unsigned long is a reasonable way to refer
to indexes inside pointters
Signed-off-by: Leah Rowe <leah@libreboot.org>
if the global file is created on a different file
system than the gbe file, unveil would trigger an
abort trap, since we rely on created a second
temporary file, whose path we can't know ahead
of time.
i could get rid of unveil, or unveil a directory,
but neither is acceptable. just use localtmp on
openbsd. a temporary file is created next to
the gbe file, in the same directory.
Signed-off-by: Leah Rowe <leah@libreboot.org>
now the custom fallback code is very unlikely
to ever actually be used, on any system,
except really old systems.
Signed-off-by: Leah Rowe <leah@libreboot.org>
Leah Rowe