lbutils/file: don't reset errno on successful io

some io syscalls may set errno on success. this patch
honours that. we try to preserve caller errno, but it
is important for debugging not to clobber it.

if fs_err_retry errs, then we don't reset errno.
if fs_err is successful but errno wasn't set, we
restore caller errno. this is done by setting errno
to zero in callers, which also restore caller errno.

Signed-off-by: Leah Rowe <leah@libreboot.org>

0 files changed, 0 insertions, 0 deletions