when wunlock() was used by threads running within the same proc,
the wunlock() can deadlock as it keeps holding the RWLock.lock
spinlock while indirectly calling _threadrendezvous(). when
_threadrendezvous() switches to another thread in the same proc,
then that thread can hang at rlock()/wlock()/runlock() again
waiting for wunlock() to release the spinlock which will never
happen as lock() does not schedule threads.
wunlock() is changed to release the spinlock during rendezvous
wakeup of readers. note that this is a bit dangerous as more
readers might queue concurrently now which means that if
we cannot keep up with the wakeups, we might keep on waking
readers forever. that will be another patch for the future.
interpreting octal breaks parsing of decimal numbers with
leading zeros. the manpage listed this in the BUGS section,
so we'r going to fix it as this just causes confusion as
most callers of atoi() do not expect it.
when we trim the front of a block with freefromfront(),
the block magic of the back was not initialized which
could sometimes trigger the assert in blocksetsize()
to fail. fix is to just move the initialization of the
magic field before the blocksetsize() call.
the second b->magic = UNALLOC_MAGIC isnt really required
but just done for consistency with the trim() code above.
passing "", "." or ".." as name caused a crash in
getenv() as it would open the directory; then seek()
to determine the file size would fail and return -1.
now checking for these special names and set
error string when its bad.
doing a single read() will not work when /env has a
9p fileserver mounted onto it and the file size is bigger
than the i/o unit. so doing incremental reads until
we get eof.
check that Free.next and Free.prev pointers are not nil.
check that Free.left and Free.right are Poison in non-tree nodes.
check that Free.left and Free.right are *not* Poison in tree nodes.
change Poison to 0xffffffffcafebabe for 64bit machines.
this fixes a potential format string problem where the
error string is passed to werrstr() as fmt. also, the
directory comparsion is simplified in this version using
a helper function.
when dial is called with a generic dialstring, it will try
/net and /net.alt in sequence. error out if the /net dial
gets interrupted and do not continue dialing /net.alt.
reduce stack usage by using the swaping nature of errstr()
instead of keeping two error string buffers on the stack.
previously, if dial was interrupted by an alarm or other note while connecting to a host that resolved to multiple ips, dial would ignore the interruption and try the next host. now dial properly returns with error when it is interrupted.
use two per process memory slots, one for the
pid and one for the fd instead of a global table
avoiding the case when the table gets full.
instead of calling pread() on the cached fd
(dangerous as it has side effects when the
fd was not closed), we check if the cached fd
is still good using fd2path() when called
the first time in this process.
theres big performance regression with this using
cwfs. cwfs calls time() to update atime on every
read/write which now causes walks on /dev.
reverting to the previous version for now. in the
long run, we'll use new _nsec() syscall but this
has to wait for a later release once new kernels
are established.
we allow protocol path to begin with # for dial, so should
allow this for announce as well. this is primarily usefull
when booting the fileserver to listen on alternate ip stack.
amd64 passes first argument in RARG (BP) register
which has the be preserved duing _profin() and
_profout() calls. to handle this we introduce
_saveret() and _savearg(). _saveret() returns
AX, _savearg() returns RARG (BP). for archs other
and amd64, _saveret() and _savearg() are the
same function, doing nothing.
restoing works with dummy function:
uintptr
_restore(uintptr, uintptr ret)
{
return ret;
}
...
ret = _saveret();
arg = _savearg();
...
return _restore(arg, ret);
as we pass arg as the first argument, RARG (BP) is
restored.
as erik quanstro suggests, theres not much of a point in
storing the full 64bit pc as one cannot get a code segment
bigger than 4G and amd64 makes it hard to use a pc that
isnt 64bit sign extension of 32bit.
instead, we only store ulong (as originally), but sign
extend back when returning in getmalloctag() and
getrealloctag().
getrealloctag() used to be broken. its now fixed.
semaphore locks have much higher overhead than initially presented
in the "Semaphores in Plan9" paper. until the reason for it has been
found out i will revert the changes.
from the manual:
Tm2sec converts a broken-down time to seconds since the
start of the epoch. It ignores wday, and assumes the local
time zone if zone is not GMT.
so we can assume localtime if Tm.zone is not set to GMT.
all code that wants no localtime conversion should set
Tm.zone explicitely to GMT. (see previous commits)
tm2sec() now does the reverse of localtime() when Tm.zone[0] == 0
which seems to be what the calling code (dossrv, zipfs) assumes.
this also makes sense because theres no simple way todo it
outside of libc as theres otherwise no access to the timezone
structure with the daylight saving periods.
doing poolcheck should give us better context to figure out
what memory blocks / owners corrupted the blocks after free.
this is for hunting down a memory corruption seen in connection
with usb serial.
