the tag-word is not compatible between x87 and sse, have to convert
properly for emulation to work.
we now copy fp state across fork (again!) to preserve FCW and MXCSR
registers. this might not be neccesary as we could probably just
get the current value for the curren process and avoid the fpsave()
call, but become conservative again.
to fix this, make genwww return 0 if w->url is nil and output an error message when attempting to access selection if it's nil. the problem with the w->url fix is that after clicking on the url scroll bar, an empty url history row could be highlighted by clicking on it. fix this by making sure lp->lo is not less than zero.
when we fail to fork resources for the child due to resource
exhaustion, make the half forked child process call pexit()
to free the resources that where allocated and error out.
imagereclaim would happily uncache pages from the mountcache (port/cache.c)
without ever getting a Image* released from it. simple fix, just check for
p->image->notext but make sure todo it under the page lock :)
the compiler optimizes setting unused variables out, which is
problematic if they are used in waserror() handler which the
compiler isnt aware of. rearrange the code to avoid this problem.
catch potential interrupt error from kproc(). this can happen when
we run out of processes, then newproc() will call rsrcwait()
which does tsleep(). if the process gets a note, this might
raise a interrupt error.
get a bit more verbose about process image exhaustion and make
imagreclaim() try to get at least one image on the freelist.
use rsrcwait() to notify the state, and call freebroken() in
case imagereclaim() couldnt free any images.
the variables elem and file0 and commited are explicitely
set to avoid that they get freed in ther waserror() handlers.
but it turns out the compiler optimizes this out as he
thinks the variables arent used any further. (the compiler
is not aware of the waserror() / longjmp() semantics).
rearrange the code to account for this. instead of using
a local variable to check for point of no return (commited),
we use up->seg[SSEG] to figure it out.
for file0 and elem, we just rearrange the code. elem can be
checked in the error handler if it was already assigned to
up->text, and file0 is just free()'d after the poperror().
remove silly busy loop in sysrendez. it is not needed.
dequeueproc() will make sure that the process has come to
rest.
we now always use the new FXSAVE format in FPsave structure and fpregs
file, converting back and forth in fpx87save() and fpx87restore().
document that fprestore() is a destructive operation now.
change fp register definition in libmach and adapt fpr() acid funciton.
avoid unneccesary copy of fpstate and fpsave in sysfork(). functions
including syscalls do not preserve the fp registers and copying fpstate
from the current process would mean we had to fpsave(&up->fpsave); first.
simply not doing it, new process starts in FPinit state.
If you run this:
{for (i in `{seq 1 70000}) echo '½•α·'} | mc | wc
mc will eventually suicide. The error comes from
/sys/src/libdraw/font.c:/^agefont which assumes it has a
display. Normally, this is set up by geninitdraw (usually
via initdraw), but mc.c avoids that to avoid the screen
redraws (flicker, at a minimum, but worse in long-running
cases).
graphics(2) does not prohibit this use, so I made the least
intrusive change to make it work.
the fpenv() instruction stores in x87 format, using mathstate()
would interpret fpsave as FPssestate in case it was enabled!
instead, pass the status word and fppc explicitely to mathnote()
in matherror().
get rid of m->fpsavealign buffer, as we can just use FPssesave struct
which has enougth padding so rounding up base pointer will not overflow.
use resrcwait() when waiting for memory to become available. randomize
the sleep time and properly restore old process status in case tsleep()
gets interrupted.
filesystems do not handle i/o errors well (cwfs will abandon the blocks),
and temporary exhaustion of kernel memory (because of too many i/o's in
parallel) causes read and write on the partition to fail.
i think it is better to wait for the memory to become available in
this case. the single allocation is at max SDmaxio bytes, which makes
it likely to become available. if we havnt even enought fo that, then
rebooting the machine would be the best option. (aux/reboot)
the fist problem is that qopen() might return nil and that kstrdup() will
sleep, so we should try to avoid holding the mntalloc lock. so we move
the kstrdup() and qopen() calls before the Mnt allocation, and properly
recover the memory if we fail later.
the second problem was that we error(Eshort) after we already created the Mnt
when returnlen < sizeof(f.version). this check has to happen *before* we
even attempt to allocate the Mnt structures. note that we only copy the
version string once everything is in the clear, so the semantics of the
user buffer not being modified in case of error is not changed.
a little cleanup in muxclose(), getting rid of mntptfree()...
pread does not guarantee that it would read all the data asked for.
But acme usage of disk assumes that. This issues as many reads as
needed to make acme work when read returns less data than it wanted.
pbs failed to load (silently loading garbage) 9BOOTFAT from start
cluster beyond FFFF because we ignored the low word from the
directory entry. now taking the high 16 bit of the directory's
start cluster into account.
Fsprotoclone() is not supposed to raise error, but return nil.
ipopen() seemed to assume otherwise as it setup error label
before calling Fsprotoclone(). fix ipopen(), make Fsprotoclone()
return nil instead of raising error.
Fsprotocone():
qopen() and qbypass() can fail and return nil, so make sure
the connection was not partially created by checking if read
and write queues have been setup by the protocol create hanler.
on error, free any resources of the partial connection and
error out.
netlogopen(): check malloc() error.
the initial fontresize() might fail but its error code is ignored
potentially leaving f->cacheimage == nil. make sure we call
fontresize() in loadchar() when theres no cacheimage and check the
return value to avoid nil pointer dereference.
instead of trying to resize the segment (which will not work when
the kernel picks the address as it will allocate right before
the base of the topmost segment), we create the mux segment with the
maximum size needed (arround 1.4MB) for OPEN_MAX filedescriptors.
buf slots will be reused and slots get demand paged once used.
1 the config string was grabbed Aoehsz too far into the packet due to using the wrong pointer to start.
2 never accept a response with tag Tmgmt or Tfree.
3 defend against "malicious" responses; ones with a response Aoehdr.type != request Aoehdr.type. this previously could
cause the initiator to crash.
4 vendor commands were improperly filtered out.
the integer division instructions are emulated with _div()
function patched in by 5l which does not handle conditional
execution. so do not optimize away the branch in that case.
