libpager, libstore: Fix crash on ENOSPC while writing data

We need to save blocked signals, otherwise longjmp will not unblock
SIGSEGV/SIGBUS, and thus next exception will kill us. Also, we need to
make sure that the preemptor is set at the right window in main memory
before letting a handler see it.

* libpager/pager-memcpy.c (do_memcpy): Call __sync_synchronize()
between aligning the fault preemptor and actually accessing data.
(fault): Use siglongjmp instead of longjmp.
(pager_memcpy): Use sigsetjmp instead of setjmp.
* libstore/memobj.c (copy, fault, memobj_memcpy): Likewise.

0 files changed, 0 insertions, 0 deletions