with scroll-wheel scrolling, this case can happen with the
command window:
umbraticus → cinap: create fullscreen file buffer by right-clicking in cmd window
slookup() copies to symb, so use the symb[NSYMB] buffer directly
to declare type conversion functions and get rid of the arbitrary
sized local buffer. replace sprint() with snprint().
We used to treat all operators as right associative,
which means that we would evaluate them incorrecty.
For example, '2 - 1 + 1' would evaluate as '2 - (1 + 2)',
instead of '(2 - 1) + 1'.
This adds an assoc parameter to struct pri, and then uses
it to decide how to evaluate operators.
when pushing expressions in cpp, particularly complex ones could
overflow the stack and silently corrupt our data structures. add
checks when we push, and bump the stack size up.
for floating point operations, reuse the return register
on the right hand side if it has higher complex number
than the left hand side to conserve registers.
this makes the following code compile, that was previously
run out of floating point register:
float
f(float r[15])
{
return (r[0] + (r[1] * (r[2] + r[3] * (r[4] + r[5] * (r[6] + r[7] * (r[8] + r[9] * (r[10] + r[11] * (r[12] + r[13] * r[14]))))))));
}
the downside is that this produces extra move operations.
BurnZeZ reported this the other day. It seems like if we have
a pipeline that looks like:
fn foo{cat < <{echo hi}}
then the '<' will get merged in /env/'fn#foo'. This change
fixes pcmd to add a space. It looks to me like this is the
only token that can get merged this way by pcmd.
The previous patch to plumb non-whitespace segments was
confusing due to lack of visual feedback. This removes
the empty selecton plumb behavior, and instead makes
triple clicking work to get a plumbable selection.
when running ndb configuration, we might inherit the ipgw=
attribute from the ipnet pointing to our own ip address
(we are the default gateway). ignore such entries.
do not add default routes with gateway equal to our own
local (ip4) or link-local ip address (ipv6).
mysbrk() was only used in gethunk() and should not be
called by anyone, so dont export the symbol.
simplify gethunk() using brk().
double allocation size on each call until we reach
1000*NHUNK.
use signed long for nhunk as alignment rountin might
make it negative and handle that case.
for gethunk() to work, all allocators have to use it,
including allocations done by libc thru malloc(),
so the fake allocation functions are mandatory for
everyone.
to avoid duplication the code is moved to cc/compat
and prototypes provided in new cc/compat.h header.
the assemblers share gethunk() cc/macbody but are compiled
without compat.c, so calls such as getenv() trigger malloc()
which does its own sbrk() calls, breaking the continuity
of the hunk.
so this change needs another revision. until then, this is
backed out.
the compilers and linkers use ther own memory allocator.
free memory is between hunk and hunk+nhunk. allocation
works by checking if nhunk is bigger or equal to the
amount needed, and if not, repeatedly call gethunk()
until there is. after that, the allocated amount is added
from hunk and subtracted from nhunk by the user.
the problem was when the needed amount was bigger than
the default NHUNK size gethunk() allocates per call.
gethunk() would not actually grow nhunk, but instead
just set hunk and nhunk variables to the last allocated
block. this resulted in a infinite loop of calls to
gethunk() until sbrk() would hit the maximum size for
the BSS segment.
this change makes gethunk() actually grow the hunk space,
increasing nhunk, and only updating hunk when nhunk was
previously zero. we assume that mysbrk() retuns increasing
addresses and that the space between the previous hunk+nhunk
and the new block base returned by mysbrk() is usable.
the real problem is that gethunk() does not grow the allocation
but just allocates a new hunk, so repeated calls to gethunk()
wont make nhunk grow to satisfy the allocation.
this will be fixed in a upcoming commit.
The swcursor used a 32x32 image for saving/restoring
screen contents for no reason.
Add a doflush argument to swcursorhide(), so that
disabling software cursor with a double buffered
softscreen is properly hidden. The doflush parameter
should be set to 0 in all other cases as swcursordraw()
will flushes both (current and previours) locations.
Make sure swcursorinit() and swcursorhide() clear the
visibility flag, even when gscreen is nil.
Remove the cursor locking and just do everything within
the drawlock. All cursor functions such as curson(),
cursoff() and setcursor() will be called drawlock
locked. This also means &cursor can be read.
Fix devmouse cursor reads and writes. We now have the
global cursor variable that is only modified under
the drawlock. So copy under drawlock.
Move the pc software cursor implementation into vgasoft
driver, so screen.c does not need to handle it as
a special case.
Remove unused functions such as drawhasclients().
most pc's are multiprocessors these days, that use apic or
msi interrupts, then the irq does not matter anymore. and
uefi does not even assign irq to pci devices anymore. if
we have a problem enabling an interrupt, we will print.
Some UEFI implementations use random UUID based DUID instead of
ethernet address, but use ethernet derived link-local addresses.
So extract the MAC from our IPv6 address.
memory returned by rampage() is not zeroed, so we have to
zero it ourselfs. apparently, this bug didnt show up as we
where zeroing conventional low memory before the new memory
map code. also rampage() never returns nil.
error handling in portreset() was wrong. we called closedev()
on the device without changing the reference.
just call portdetach() when the reset fails.
This replaces the memory map code for both pc and pc64
kernels with a unified implementation using the new
portable memory map code.
The main motivation is to be robust against broken
e820 memory maps by the bios and delay the Conf.mem[]
allocation after archinit(), so mp and acpi tables
can be reserved and excluded from user memory.
There are a few changes:
new memreserve() function has been added for archinit()
to reserve bios and acpi tables.
upareserve() has been replaced by upaalloc(), which now
has an address argument.
umbrwmalloc() and umbmalloc() have been replaced by
umballoc().
both upaalloc() and umballoc() return physical addresses
or -1 on error. the physical address -1 is now used as
a sentinel value instead of 0 when dealing with physical
addresses.
archmp and archacpi now always use vmap() to access
the bios tables and reserve the ranges. more overflow
checks have been added.
ramscan() has been rewritten using vmap().
to handle the population of kernel memory, pc and pc64
now have pmap() and punmap() functions to do permanent
mappings.
This is a generic memory map for physical addresses. Entries
can be added with memmapadd() giving a range and a type.
Ranges can be allocated and freed from the map. The code
automatically resolves overlapping ranges by type priority.
Fix the inconsistent use of ether->mem. Always use physical
addresses. Let ether8390 convert to virtual addresses using
KADDR() when we have to copy data in/out.
in ndb, we use the ethernet mac to identify the client.
in dhcpv6, there is just a uniqueue device id that
might even be generated randomly. to find the ethernet
address of a client, check the duid type and only use
it when the dudid is of type 1 (link layer) or 3 (link
layer address + time) and the link layer address type
is 1 (ethernet). otherwise, assume the source ip is
a link local address and extract it from that.
this hack works for thinkpad t495, which uses random
uuid based client duid.
the previous mkfile had a sneaky hack that would use
sed to delete the first 2 lines of hex output to strip
the 32 byte long a.out header for apbootstrap and rebootcode.
use 8l -H3 flag to strip the header from the output file.
Output buffering is automatically disabled when reading from stdin.
In this case, supplying the -b flag ought to be redundant. However,
since Bflag was being XORed into the flag set - rather than simply
ORed - supplying -b would actually enable output buffering.
while technically a 32 bit ptrdiff_t is in spec on
systems with 64 bit ponters as long as we guarantee
that individual objects are small enough, this can
confuse legitimate code, so lets fix this.
This fixes token pasting, making it expand when
it should expand, and paste before expansion when
it should paste before expanding.
#define CAT(a, b) a ## b
#define BAR 3
#define FOO CAT(BAR, 3)
FOO
now produces 33, while
#define CAT(a, b) a ## b
#define EOF (-1)
#define NOP(x) x
NOP(CAT(foo, EOF))
CAT(,EOF)
CAT(,)
produces
fooEOF
(-1)
<empty>
respectively.
ccom may be called multiple times on the same
node, via 'goto loop' calls from the commute
label, OADD, and a few other places.
Casts to void could null out the LHS of the
node, which would cause the compiler to crash
if the cast was revisited due to one of these
cases, because we tried frobbing n->left.
Now, if n->left is nil, we just return.w
Fix inconsistencies between programs and their usage
messages, correct instances where information seems
to be missing or lost. This includes missing arguments,
making usage consistent with manuals, and so on.
we emitted an error on heredoc tags, but we
continued on, and added a heredoc entry to
the list, with a tag that we couldn't handle.
when processing this heredoc, rc would segfault.
fix: don't add a heredoc to the list on error.
We used to have a padding int in the structure
after the next pointer, to align it to 16 bytes.
On 64 bit architectures, the pointer was already
8 bits, so the padding misaligned things to 20
bytes.
This fixes it so that we're explcit about the
data alignment we want, instead of hoping that
the various sizes line up.
with the latest changes to shr(3), we can use ORCLOSE on
the control file to get the mount in the share automatically
removed when the server exits or something goes wrong during
postsharesrv().
do not expose postfd() and sharefd() functions. they where
undocumented and leak the control file descriptors.
the rc & operator changes stdin to /dev/null, so we
have to do the <[0=1] inside the {}
this never showed up as an issue because many
fileservers just read 9p messages from standard
output.
when the control mountpoint side gets removed, close
mount channel immediately. this is usefull for implementing
automatic cleanup with ORCLOSE create mode.
this makes sure that when postsharesrv() fails (for
example because the shr file already exists), the
worker process gets killed and all file descriptors
to devusb get closed.
allow reading the control file of a process and return
its pid number. if the process has exited, return an error.
this can be usefull as a way to test if a process is
still alive. and also makes it behave similar to
network protocol directories.
another side effect is that processes who erroneously
open the ctl file ORDWR would be allowed todo so as
along as they have write permission and the process is
not a kernel process.
it appears that too many fileservers rely on the fileserver
process sharing the filedescriptors with children of the
caller to postmntsrv() or threadpostmntsrv().
restoring previous behaviour for now.
sshreadproc() needs to be started after opening the sshfd file
descriptor.
fsnetproc() needs to run in the same filedescriptor group as
the fileserver.
run the usb hub poll "work()" proc in the same filedescriptor
group as the fileserver by forking the process in Srv.start
callback.
this also prevents the usbbusy filedescriptor from being kept
open by the fileserver process.
mike from eff0ff.net reported the following:
> I was running a second instance of rio inside a rio window and
> suddenly weird things started happening. The second instance started
> imposing arbitrary limits on the size of its windows and refused to
> resize some of its windows when its own window was resized.
> Turns out this happens if rio's screen is 3 times as high as wide
> because of a tiny mistake in its goodrect function.
... and kindly provided a patch. thanks!
with the -s flag, we should read 9P messages from
standard *INPUT* (fd 0) and write responses to
standard *OUTPUT* (fd 1).
before these servers where reading from fd 1,
assuming they where both the same files.
it is unclear how Srv.nopipe flag should work inside
postmountserv(). if a server wants to serve on stdio
descriptors, he can just call srv() after initializing
Srv.infd and Srv.outfd.
The Srv.leavefdsopen hack can be removed now that acme
win has been fixed.
in case listensrv() is called with a previously active Srv,
we have to make sure that per connection state is zeroed
out (locks and reference conuts).
also, dont assume anything about the Ref structure. there
might be implementations that have a spinlock in them.
loadrevinfo() would fail on a empty log portion due
to a bug in the previous commit.
the loop is supposed to skip all bytes until we encounter
a empty line. the loop starts at the beginning of a line
so when we encounter a \n, we have to terminate, otherwise
read bytes until we see \n (end of a line) and then read
another and test the condition again.
progarg[0] can be assigned to elem directly as it is a
copy in kernel memory, so the char proelem[64] buffer
is not neccesary.
do the close-on-exit outside of the segment lock. there
is no reason to keep the segment table locked.
the user buffer could be changed while we parse it resulting
in a different number of watchpoints than initially calculated.
so add a check to the parse loop so we wont overflow the
watchpoint array.
in case the calling process changes its arguments under us, it could
happen that the final argument string lengths become bigger than
initially calculated. this is fine as we still make sure we wont
overflow the stack segment, but we could overrun into the tos
structure at the end of the stack. so change the limit to the
base of the tos, not the end of the stack segment.
writes to /proc/n/notepg and /proc/n/note should be able to write
at ERRMAX-1 bytes, not ERRMAX-2.
simplify write to /proc/n/args by just copying to local buf first
and then doing a kstrdup(). the value of Proc.nargs does not matter
when Proc.setargs is 1.
Section 6.5.15 of the C99 spec requires that if
one argument of a ?: expression is a null pointer
constant, and the other has a pointer type T*, then
the type of the expression is T*.
We were attempting to follow this rule, however,
we only handled literal expressions when checking
for null pointers.
This change looks through casts, so 'nil' and 'NULL',
and their expansion '(void*)0' are all detected as
null pointer constants.
devproc assumes that when we hold the Proc.debug qlock,
the process will be prevented from exiting. but there is
another race where the process has already exited and
the Proc* slot gets reused. to solve this, on process
creation we also have to acquire the debug qlock while
initializing the fields of the process. this also means
newproc() should only initialize fields *not* protected
by the debug qlock.
always acquire the Proc.debug qlock when changing strings
in the proc structure to avoid doublefree on concurrent
update. for changing the user string, we add a procsetuser()
function that does this for auth.c and devcap.
remove pgrpnote() from pgrp.c and replace by static
postnotepg() in devproc.
avoid the assumption that the Proc* entries returned by
proctab() are continuous.
fixed devproc permission issues:
- make sure only eve can access /proc/trace
- none should only be allowed to read its own /proc/n/text
- move Proc.kp checks into procopen()
pid reuse was not handled correctly, as we where only
checking if a pid had a living process, but there still
could be processes expecting a particular parentpid or
noteid.
this is now addressed with reference counted Pid
structures which are organized in a hash table.
read access to the hash table does not require locks
which will be usefull for dtracy later.
Currently upas/fs plumbs modify messages only if the flag
changes are made by another imap connection. If the flag
changes are made within the running upas/fs no modify message
is plumbed.
This changes upas/fs to set the modify flag if we made the
change ourself. It also moves the flag setting before the
imap read, so that we don't clobber flag changes coming
from the imap server with our own flags.
(Thanks Tobias Heinicke)
replace machine specific userinit() by a portable
implemntation that uses kproc() to create the first
process. the initcode text is mapped using kmap(),
so there is no need for machine specific tmpmap()
functions.
initcode stack preparation should be done in init0()
where the stack is mapped and can be accessed directly.
replacing the machine specific userinit() allows some
big simplifications as sysrfork() and kproc() are now
the only callers of newproc() and we can avoid initializing
fields that we know are being initialized by these
callers.
rename autogenerated init.h and reboot.h headers.
the initcode[] and rebootcode[] blobs are now in *.i
files and hex generation was moved to portmkfile. the
machine specific mkfile only needs to specify how to
build rebootcode.out and initcode.out.
to prevent deadlock on media unbind (which is called with
the interface wlock()'ed), the medias reader processes
that unbind was waiting for used to discard packets when
the interface could not be rlocked.
this has the unfortunate side effect that when we change
addresses on a interface that packets are getting lost.
this is problematic for the processing of ipv6 router
advertisements when multiple RA's are getting received
in quick succession.
this change removes that packet dropping behaviour and
instead changes the unbind process to avoid the deadlock
by wunlock()ing the interface temporarily while waiting
for the reader processes to finish. the interface media
is also changed to the mullmedium before unlocking (see
the comment).
avm fritzbox uses very long RA period so it effectively only
responds after a router solicitation. when there are multiple
fritzbox routers on the lan, then while configuring one prefix
of the first RA, the ip stack can drop the second router
advertisement and we would never get the second route.
packets can always get lost. so we just keep on sending router
solicitations (up to 3 times) to make sure we got all the RA's.
This patch makes 3 changes:
- It makes upas/fs send plumb messages when a message
changes in the background (eg, someone on another imap
connection opens a message and sets the read flag)
- It makes faces not complain when it gets one of these
new modify messages.
- It makes acme/Mail update the flags in the display
when it gets one of these messages.
on systems with serial console and graphics such as the raspberry pi,
it is nice to get a system shell on the serial console even when no
monitor is connected.
the console command runs a command or the system shell under
a new instance of kbdfs, optionally providing a serial console
when $console environment variable is set.
comparing m with MACHP() is wrong as m is a constant on 386.
add procflushothers(), which flushes all processes except up
using common procflushmmu() routine.
procflushmmu() returns once all *OTHER* processors that had
matching processes running on them flushed ther tlb/mmu state.
the caller of procflush...() takes care of flushing "up" by
calling flushmmu() later.
if the current process matched, then that means m->flushmmu
would be set, and hzclock() would call flushmmu() again.
to avoid this, we now check up->newtlb in addition to m->flushmmu
in hzclock() before calling flushmmu().
we also maintain information on which process on what processor
to wait for locally, which helps making progress when multiple
procflushmmu()'s are running concurrently.
in addition, this makes the wait condition for procflushmmu()
more sophisticated, by validating if the processor still runs
the selected process and only if it matchatches, considers
the MACHP(nm)->flushmmu flag.
The code had a nested use of the follow() function that could cause +=+
and -=- to register as ++ and --. The first follow() to execute could
consume a character and match and then the second follow() could consume
another character and match. For example i-=-10 would result in a syntax
error and i-=- would decrement i.
(imported from plan9port commit f1dd3f065a97f57bf59db2e3284868e181734159)
the change to support no-execute bits broke the original
raspberry pi1, as it uses backwards compatible page table
format.
to use the XN bit, subpage AP bits have to be disabled
using the XP bit in CP15 Control Register c1 Bit 23.
When plumbing an address like `3-`, Acme selects line 1,
and similarly `3+` selects line 5.
The same problem can be observed for character addresses (`#123+`)
but _not_ for ones like `+`, `.+` or `/foo/+`:
The problem only occurs when a number is followed by a direction (`-`/`+`).
Following along with the example `3-` through `address` (in addr.c):
We read `3` into `c` and match the `case` on line 239.
The `while` loop on line 242ff reads additional digits into `c`
and puts the first non-digit back by decrementing the index `q`.
Then we find the range for line 3 on line 251 and continue.
On the next iteration, we set `prevc` to the last `c`,
but since that part read ahead _into `c`_,
`c` is currently the _next_ character we will read, `-`,
and now `prevc` is too.
Then in the case block (line 210) the condition on line 211 holds
and Acme believes that it has read two `-` in sequence
and modifies the range to account for the “first” `-`.
The “second” `-` gets applied after the loop is done, on line 292.
So the general problem is:
While reading numbers, Acme reads the next character after the number into `c`.
It decrements the counter to ensure it will read it again on the next iteration,
but it still uses it to update `prevc`.
This change solves the problem by reading digits into `nc` instead.
This variable is used to similar effect in the block for directions (line 212)
and fills the role of “local `c` that we can safely use to read ahead” nicely.
(imported from plan9front a82a8b6368274d77d42f526e379b74e79c137e26)
To reproduce, create a column with at least two windows and resize
acme to have almost zero height.
(imported from plan9port commit 76b9347a5fa3a0970527c6ee1b97ef1c714f636b)
when a process does an exec syscall, procsetup() is called and
we have to disable the debug watchpoint registers. just clearing
p->dr is not enougth as we are not going thru a procsave() and
procrestore() cycle which would disable and reload the saved
debug registers.
instead of clearing debug registers in procfork(), we should
clear the saved debug registers before a process goes to die
(pexit() calls sched() with up->state = Moribund) as the Proc
structure can get reused for kernel processes (kproc) which
never call procfork() and would therefore have debug registers
loaded.
do incremental imap fetches after startup, fixes validity handling,
record flags correctly when we aren't in the process of directly
updating a message, fixes off by one in flag parsing, fixes
mis-indexing messages in sync when we get an unsolicited fetch
response.
for better system diagnostics, we *ALWAYS* want to record the parent
pid of a user process, regardless of if the child will post a wait
record on exit or not.
for that, we reverse the roles of Proc.parent and Proc.parentpid so
Proc.parentpid will always be set on rfork() and the Proc.parent
pointer will point to the parent's Proc structure or is set to nil
when no wait record should be posted on exit (RFNOWAIT flag).
this means that we can get the pid of the original parent process
from /proc, regardless of the the child having rforked with the
RFNOWAIT flag. this improves the output of pstree(1) somewhat if
the parent is still alive. note that theres no guarantee that the
parent pid is still valid.
the conditions are unchanged:
a user process that will post wait record has:
up->kp == 0 && up->parent != nil && up->parent->pid == up->parentpid
the boot process is:
up->kp == 0 && up->parent == nil && up->parentpid == 0
and kproc's have:
up->kp != 0 && up->parent == nil && up->parentpid == 0
this is a reimplementation of infernos os(1) command, which
allows running commands in the underhying host operating
system when inferno runs in hosted mode (emu). but unlike
inferno, we want to use it to run commands on the client
side of a inferno or drawterm session from the plan9 cpu
server, so it defaults to /mnt/term/cmd for the mountpoint.
Previously, reads of wctl files would return one byte less than
requested as the returned string must be null terminated. Now we pass
the actual size of the allocated buffer to the handler, which is large
enough to accommodate a trailing partial rune and terminating null
byte.
Ori_B reports that his controller gets stuck in the ahciencreset()
wait loop. so we implement a 1000 ms timeout. we replace delay()
with esleep() as we are always called from the ledkproc().
blink() could enter infinite delay loop as well, so instead of
waiting for the message to get transmitted we exit making it
non-blocking (we will get called again anyway).
the access to the controller map[] was wrong in ledkproc(). the
index is the controller number, not the drive number!
Support for 'path=', 'uname=', 'gname=', 'size=', and 'atime=' pax
headers is useful. Others are ignored, possibly with a warning.
We were running into missing support with the 'go' extraction.
At the same time, this cleans up the way that we handle paths,
getting rid of static buffers with hidden space at the front.
when making outgoing connections, the source ip was selected
by just iterating from the first to the last interface and
trying each local address until a route was found. the result
was kind of hard to predict as it depends on the interface
order.
this change replaces the algorithm with the route lookup algorithm
that we already have which takes more specific desination and
source prefixes into account. so the order of interfaces does
not matter anymore.
Tar specifies that a filename ending with '/' is a directory. We were
incorrectly looking at the short name. This meant that when we have long
filenames with a '/' at the 100th character, we would decide it was a
directory.
This change uses the long name when deciding the size for extraction,
and trusts the header size when just skipping forward in the stream.
extract1() expects two extra bytes to be avilabe before
fname buffer so it can prepend ./ before the name. this
used to be the case with name(), but was violated when
long name support was added and getname() was used in
place of name() which did not reserve the 2 extra bytes.
this change reserves two extra bytes in the getname()'s
static buffer and also removes the extra copy as name()
already makes a copy.
Since numeric timezone offsets are relative to GMT, initialise zone to
GMT so tm2sec(2) does not assume local time.
Note that if strtotm encounters a timezone *string* and consequently
overwrites zone then we will end up in the same mess since tm2sec(2)
only deals with GMT or local time.
there was a race between the sendproc putting the request on
the sreqrd[] id and the recvproc handling the response, and
potentially freeing the request before the sendproc() was
finished with the request (or the fid).
so we defer allocating a request id and putting it on the
sreqrd[] stage after we have completely generated the
request in vpack(). this prevents the handling of the request
before it is even sent.
this also means that the SReq should not be touched after
calling sendpkt(), submitreq(), submitsreq().
secondly, putsfid() needs to acquire the RWLock to make sure
sendproc() is finished with the request. the scenario is that
recvproc() can call respond() on the request before sendproc()
has unlocked the SFid.
move digest pointer into Mtree structrue and embed it into Idx struct
(which is embedded in Message) to avoid one level of indirection
during mtreecmp().
get rid of mtreeisdup(). instead we have mtreeadd() return the old
message in case of a collision. this avoids double lookup.
increase the hash table size for henter() and make it a prime.
on 386, the kernel memory region is mapped using huge 4MB pages
(when supported by the cpu). so the uncached pte manipulation
does not work to map the cursor data with uncached attribute.
instead, we allocate a memory page using newpage() and map
it globally using vmap(), which maps it uncached.
after issuing CR_RESETEP command, we have to invalidate
the endpoints output context buffer so that the halted/error
status reflects the new state. not doing so resulted in
the halted state to be stuck and we continued issuing
endpoint reset commands when we where already recovered.
handle the devusb Ep.clrhalt flag from devusb that userspace
uses to force a endpoint reset on the next transaction.
for servers that handle incoming network connections and authentication,
change the owner of the network connection file to the authenticated user
after successfull authentication.
note that we set the permissions as well to 0660 because old devip used
to unconditionally set the bits.
permission checking had the "other" and "owner" bits swapped plus incoming
connections where always owned by "network" instead of the owner of
the listening connection. also, ipwstat() was not effective as the uid
strings where not parsed.
this fixes the permission checks for data/ctl/err file and makes incoming
connections inherit the owner from the listening connection.
we also allow ipwstat() to change ownership to the commonuser() or anyone
if we are eve.
we might have to add additional restrictions for none at a later point...
we want devip to get reattached after hostowner has been written. factotum
already handles this with a private authdial() routine that mounts devip
when it is not present. so we detach devmnt before starting factotum,
and attach once factotum finishes.
the locking in proctext() is wrong. we have to acquire Proc.seglock
when reading segments from Proc.seg[] as segments do not
have a private freelist and can therefore be reused for other
data structures.
once we have Proc.seglock acquired, check that the process pid
is still valid so we wont accidentally read some other processes
segments. (for both proctext() and procctlmemio()). this also
should give better error message to distinguish the case when
the process did segdetach() the segment in question before we
could acquire Proc.seglock.
declare private functions as static.
