flag.
EMUL_BSD_ASYNCIO_PIPE notes that the emulated binaries expect the original
BSD pipe behavior for asynchronous I/O, which is to fire SIGIO on read() and
write(). OSes without this flag do not expect any SIGIO to be fired on
read() and write() for pipes, even when async I/O was requested. As far as
we know, the OSes that need EMUL_BSD_ASYNCIO_PIPE are NetBSD, OSF/1 and
Darwin.
EMUL_BSD_ASYNCIO_PIPE notes that the emulated binaries expect the original
BSD pipe behavior for asynchronous I/O, which is to fire SIGIO on read() and
write(). OSes without this flag do not expect any SIGIO to be fired on
read() and write() for pipes, even when async I/O was requested. As far as
we know, the OSes that need EMUL_BSD_ASYNCIO_PIPE are NetBSD, OSF/1 and
Darwin.
EMUL_NO_SIGIO_ON_READ notes that the emulated binaries that requested
asynchrnous I/O expect the reader process to be notified by a SIGIO, but
not the writer process. OSes without this flag expect the reader and the
writer to be notified when some data has arrived or when some data have been
read. As far as we know, the OSes that need EMUL_NO_SIGIO_ON_READ are Linux
and SunOS.
Change the add/subtract overflow checks to use an unsigned to do the op
and then cast back into the signed var to check the signs.
Make multiply shortcut on either right or left being 0.
Make multiply's overflow test not fail on simple cases like 1 * -1
Make the multiple overflow test pass all the regress tests.
1. use uintptr_t instead of u_long
2. check for overflow in map_pages and malloc_pages
3. bring in fixes from FreeBSD [int -> size_t, and a missing THREAD_UNLOCK]
4. rewrite map_pages to use sbrk() only to grow memory (avoids extra syscall
and elides bug in brk(2) that ross is fixing)
5. restore the break point to its original value if the mmap(2) for the page
directory or the alignment sbrk breaks.
reviewed by: chuq and ross
tested by: make build and reboot
Now memtest nearly works; unfortunately there is no way currently to lower
the break point as we free, so memtest keeps trying to reduce memory when
mlock() fails and that does not work.
