*alen has to be initialized to the size of the buffer
by the caller, and we are supposed to put the real
size of the address in there, but not copy more than
the original *alen value (truncate).
in wpa2, the rsc field of the eapol message3 is the packet number for
*group* messages that the ap will use as there is no separate group
key message. in wpa1, we use it for the peerwise key.
the kernel uses fixed area (TSTKTOP, TSTKSIZ) of the address
space to temporarily map the new stack segment for exec. for
386 and arm, this area was right below the stack segment which
has the problem that the program can map arbitrary segments
there (even readonly).
alpha and ppc dont have this problem as they map the temporary
exec stack *above* the user reachable stack segement and segattach
prevents one from mapping anything above or overlaping the stack.
lots of arch code assumes USTKTOP being the end of userspace
address space and changing this to TSTKTOP would work, but results
in lots of hard to test changes.
instead, we'r going to map the temporary stack programmatically
finding a hole in the address space where to map it. we also lift
the size limitation for arguments and allow arguments to fill
the whole new stack segement.
the TSTKTOP and TSTKSIZ are not used anymore so they where removed.
references:
http://9fans.net/archive/2013/03/203http://9fans.net/archive/2013/03/202http://9fans.net/archive/2013/03/197http://9fans.net/archive/2013/03/195http://9fans.net/archive/2013/03/181
store errno on the private process stack so its always per process
and not just per memory space. errno itself becomes a macro
dereferencing int *_errnoloc; which is initialized from main9.s
pointing to the private stack location.
various fixes in programs that just imported errno variable with
"extern int errno;" instead of including <errno.h>.
in ape close(), do the real filedescriptor _CLOSE() *after* we cleared
the _fdinfo[] slot because once closed, we dont own the slot anymore and
another process doing open() can trash the slot. make sure open() retuns
fd < OPEN_MAX.
double check in _startbuf() holding mux->lock if the fd is already buffered
preveting running double copyprocs on a fd.
dont zero the mux->rwant/ewant bitmaps at the end of select() as we do not
hold the mix->lock.
in _closebuf() kill copyproc while holding the mux->lock to make sure the
copyproc isnt holding it at the time it is killed. run kill() multiple times
to make sure the proc is gone.
python uses processes sharing memory. it requires at least fopen() to
be called by multiple threads at once so we introduce _IO_newfile()
which allocates the FILE structure slot under a lock.
diskparts fails on thinkpad x200 sdcard reader if we dont
give the unit some time to startup. the device took about
100ms to become ready so status poll loop with a long
timeout would be overkill.
