avoid double entries in the cache for copen() and properly handle
locking so we wont just give up if we cant lock the Mntcache entry,
but drop the cache lock, qlock the Mntcache entry, and then recheck
the cache.
general cleanup (cdev -> ccache, use eqchantdqid())
the lock order of page.Lock -> palloc.hashlock was
violated in cachedel() which is called from the
pager. change the code to do it in the right oder
to prevent deadlock.
change lookpage to retry on false hit. i assume that
a false hit means:
a) we'r low on memory -> cached page got uncached/reused
b) duppage() got called on the page, meaning theres another
cached copy in the image now.
paging in is expensive compared to the hashtable lookup, so
i think retrying is better.
cleanup fixfault, adding comments.
swaped pages use a 8bit refcount where as the Page uses a 16bit one.
this might be exploited with having a process having a single page
swaped out and then forking 255 times to make the swap map refcount
overflow and panic the kernel.
this condition is probably very rare. so instead of doubling the
size of the swap map, we add a single 32bit refcount swapalloc.xref
which will keep the combined refcount of all swap map entries who
exceeded 255 references.
zero swapimage.c in setswapchan() after closing it as the stat() call
below might error leaving a dangeling pointer.
attachimage()'s approach to handling newseg() error is flawed:
a) the the image is on the hash table, but ref is still 0, and
there is no segment/pages attached to it so nobody is going to
reclaim / putimage() it -> leak
b) calling pexit() would deadlock us because exec has acquired
up->seglock when calling attachimage(), so this would just deadlock.
the fix does the following:
attachimage() will putimage() and nexterror() if newseg() fails
instead of pexit(). this is less surprising.
exec now keeps the condition variable commit which is set once
we are commited / reached the point of no return and check this
variable in the highest waserror() handler and pexit() us there.
this way we have released up all the locks and pexit() will
cleanup.
note: this bug shouldnt us hit in with the current newseg()
implementation as it uses smalloc() which would wait to
satisfy the allocation instead of erroring.
kstrcpy() did not null terminate for < 4 byte buffers. fixed,
but i dont think there is any case where this can happen in
practice.
always set malloctag in kstrdup(), cleanup.
always use ERRMAX bounded kstrcpy() to set up->errstr, q->err
and note[]->msg. paranoia.
instead of silently truncating interface name in netifinit(),
panic the kernel if interface name is too long as this case
is clearly a mistake.
panic kernel when filename is too long for addbootfile() in
devroot. this might happen if your kernel configuration is
messed up.
When running "?c -p ...", ensure the backend cpp recognizes C++ comments.
2c(1) states that the compilers recognize // comments, and the bare compilers
do. But if you invoke the compiler with '-p', the backend cpp process
doesn't handle // comments properly unless you also give ?c the undocumented
'-+' option (which it passes through to cpp).
in devproc status read handler the p->status, p->text and p->user
could overflow the local statbuf buffer as they where copied into
it with code like: memmove(statbuf+someoff, p->text, strlen(p->text)).
now using readstr() which will truncate if the string is too long.
make strncpy() usage consistent, make sure results are always null
terminated.
use fastclock timer (pit2) to measure cpufreq in guesscpuhz(). this
gives a bigger period minimizing the danger of overrun as pit2 runs
at the constant maximum period of 0x10000 ticks. also use smaller
loop increments (1000) and bigger maximum loop upper bound.
move the loops < ... check to the bottom of the loop so we get the
effective count *before* adding the next loop increment.
ilock() while doing measurements in guesscpuhz() to prevent accidents
with other processors reading fastclock or doing guesscpuhz()
in parralel.
export new i8253reset() function for apm to reset the timers after
a apm bios suspend.
we have to acquire p->seglock before we lock the individual
segments of the process and lock them. if we dont then pexit()
might free the segments before we can lock them causing the
"qunlock called with qlock not held, from ..." prints.
* disallow snarf on password entries
* remove current title label as it is displayed in the page list (redundant)
* avoid redrawing page list just to update the title
* check if the chan changed for backup bitmap in pl_rtdraw()
send ACK reply for duplicate data packets in case our ack response
got lost. make sure packets are in sequence and ignore out of
oder packets (except the ones we'v already acked).
to make it easy to use normal libraries (such as libdraw, libsec, and libmp)
with the kernel, which uses extern register, don't stray into the external
register set when allocating values to registers.
sometimes, the bios does not assign a interrupt line for pci
devices. this should not be fatal in case of mp ineterrupts
as long as there is intpin or msi can be used.
warn in intrenable() if we hit such a interrupt and set
irq to -1 to prevent it from getting enabled on the pic
or as isa interrupt in apic mode.
removing the querylck from the DN as it was never used or being
effective which saves like a ton on space per domain name.
remove the Query.tcplock and put query on the stack. it is
unneccesary to lock the query as its only used by one process
at a time. put Query's on the stack.
change outsidens() to outsidensip() which now takes the ip
buffer that it fills instead of returning static buffer (which
would race with multiple processes involved).
eleminate mostly all of the lock(&dnlock)/unlock(&dnlock) calls.
we'r not working on shared cache RR's in the resolver procs.
we work on *copies* done by rrlookup() made under the dnlock.
the cache garbage collection only runs when all processes are
locked out and is also taking the dnlock while doing so.
cleanup xmitquery(). for the tcp case, we dont need to get
more nameserver addresses, just take the ip from the udp header
that tcpquery() placed there for us.
fixed baddelegation() to actually check for delegation loop even
if theres no dom info for our host.
remove lots of debug code. remove the dnforceage() as it doenst
make sure other processes are locked out. this could destroy
dn's currenctly refered by running queries.
remove dnageallnever() as its not used. dont attach rr's to
keepers to prevent outside spoofing.
make myaddr() retrive the ip address if not set.
we used to only test the checksum of the PCMP structure referenced by
the _MP_ without checking _MP_ itself. now fixed.
geoff added some coherence() calls and comments in the mpstartup and
apic code which seems to be a good idea.
replace the various functions that searched for bios data structures by
a single sigsearch() one in pc/memory.c that will probe the various bios
data areas.
also, a new checksum() function was added that is to be used to validate
the structures found.
always make sure that there are child processes we can wait for
before sleeping.
put pwait() sleep into a loop and recheck. this is not strictly
neccesary but prevents accidents if there are spurious wakeups
or a bug.
once we set q->done = 1 in mountmux, the sleeper might return freeing q
so the wakeup might access invalid memory. we change the embedded Rendez
structure in the Mntrpc into a pointer to the sleeping procs up->sleep
rendez so the rendez is always going to be valid even if the rpc has been
freed.
the call to mntstats was moved before we set q->done also to prevent
accessing invalid memory.
wakeup cannot access r->sleep once we set r->done because the
sleeper might just return at this point making r invalid. make
a copy of the sleep rendez pointer before setting r->done.
