Hello,
I am using X11.app 1.0 on Mac OS X 10.3.5 with an iBook using the wireless
airport for networking. I experience the following problem. When I move
from one location to another at work I can no longer launch X11
applications. I have narrowed the problem.
First when I start X11.app:
% xauth list
d-r12345.dhcp.foo.bar/unix:1 MIT-MAGIC-COOKIE-1 cookie
d-r12345.dhcp.foo.bar:1 MIT-MAGIC-COOKIE-1 cookie
localhost:1 MIT-MAGIC-COOKIE-1 cookie
My-Computer.local/unix:1 MIT-MAGIC-COOKIE-1 cookie
(The details have been changed and yes I have two instances of X11.app
running using FUS.)
The cookie for d-r12345.dhcp.foo.bar/unix:1 is key because this is what
allows me to run local X11 applications on my iBook.
Now if I move to a different location, I will get a new IP address from
DHCP, after this change in network status my cookies will look something
like this:
% xauth list
My-Computer.local/unix:1 MIT-MAGIC-COOKIE-1 cookie
d-r67890.dhcp.foo.bar:1 MIT-MAGIC-COOKIE-1 cookie
localhost:1 MIT-MAGIC-COOKIE-1 cookie
Now local X11 applications will not launch:
% xclock
Xlib: connection to ":1.0" refused by server
Xlib: No protocol specified
Error: Can't open display: :1.0
The error is that there is no unix socket cookie entry, specifically
after:
% xauth add d-r67890.dhcp.foo.bar/unix:1 MIT-MAGIC-COOKIE-1 cookie
Now local X11 applications work again.
This problem can be reproduced with wireless by turning the airport
network off and then on again. If the airport is ON and X11.app is
launched, both the remote and local cookies are in the the .Xauthority
file. When the airport is turned OFF, both cookies are removed
automatically. When the airport is turned ON again, only the remote cookie
is added. (Even if you recieve the same IP address.) There is no /unix
cookie for local connection to the X11 server using the unix socket.
I was curious what program monitors the change in Network status and adds
and removes cookies automatically so I ran this:
# fs_usage -e -w -f filesys > fs_usage.out
Then I looked for references to .Xauthority:
17:06:13.318 lstat [ 2] /Users/baz/.XauthoritykL2FhF 0.000111 X11
17:06:13.318 stat [ 2] /Users/baz/.Xauthority-c 0.000015 X11
17:06:13.319 open F=13 /Users/baz/.Xauthority-c 0.000594 W X11
17:06:13.319 close F=13 0.000019 X11
17:06:13.319 link /Users/baz/.Xauthority-c 0.000567 X11
17:06:13.320 open F=13 /Users/baz/.XauthoritykL2FhF 0.000232 X11
17:06:13.320 open F=14 /Users/baz/.Xauthority 0.000243 X11
17:06:13.320 fstat F=14 0.000007 X11
17:06:13.320 read F=14 B=0xc8 0.000046 X11
17:06:13.320 read F=14 B=0x0 0.000003 X11
17:06:13.320 close F=14 0.000012 X11
17:06:13.320 close F=13 0.000002 X11
17:06:13.321 unlink /Users/baz/.Xauthority 0.000359 X11
17:06:13.321 rename /Users/baz/.XauthoritykL2FhF 0.000267 X11
17:06:13.321 unlink /Users/baz/.Xauthority-c 0.000198 X11
17:06:13.322 unlink /Users/baz/.Xauthority-l 0.000437 X11
17:06:13.322 open F=13 /dev/random 0.000131 X11
17:06:13.322 read F=13 B=0x10 0.000153 X11
17:06:13.322 lstat [ 2] /Users/baz/.XauthorityHLOmRm 0.000046 X11
17:06:13.322 stat [ 2] /Users/baz/.Xauthority-c 0.000015 X11
17:06:13.322 open F=14 /Users/baz/.Xauthority-c 0.000279 X11
17:06:13.322 close F=14 0.000012 X11
17:06:13.323 link /Users/baz/.Xauthority-c 0.000490 X11
17:06:13.323 open F=14 /Users/baz/.XauthorityHLOmRm 0.000189 X11
17:06:13.323 fstat F=14 0.000003 X11
17:06:13.323 open F=15 /Users/baz/.Xauthority 0.000041 X11
17:06:13.323 fstat F=15 0.000002 X11
17:06:13.323 read F=15 B=0x0 0.000020 X11
17:06:13.323 close F=15 0.000004 X11
17:06:13.323 write F=14 B=0x80 0.000134 X11
17:06:13.324 close F=14 0.000346 X11
17:06:13.324 unlink /Users/baz/.Xauthority 0.000240 X11
17:06:13.324 rename /Users/baz/.XauthorityHLOmRm 0.000243 X11
17:06:13.324 WrData[async] D=0x03b03680 B=0x200 /dev/disk0s5 0.000818 W X11
This was repeated later on with another similar list of syscalls and fs
activity for the other instance of X11.app. It is clear from this that it
is X11.app itself that removes/adds the cookie(s) with some -c and -l
locking and writing to a temporary file and renaming it to the .Xauthority
file.
So it would appear that there is a bug in X11.app, it should in fact add
both the remote (:) and local (/unix:) cookies. Also why is X11.app not
forking and using xauth to do this? (Whatever that is just style.) I can
perform the xauth add command when I remember but when I forget the
consequences are annoying because of an in-house X11 application I use.
When it fails to spawn a new X11 application, the program becomes unusable
andI must quit it and restart losing all progress to that point.
Maybe there is a simple work around like making the machine name static,
or a convuluted solution using /System/Library/SystemConfiguration/Kicker
but I hope that either I misubderstand something or that someone on this
list has a simple work around that allows me to still have a dynamic
host name.
On another note, there is possibly a file descriptor leak in X11.app.
Granted I only captured a small portion of the running of X11.app with
fs_usage, if you notice this:
17:06:13.322 open F=13 /dev/random 0.000131 X11
I would have expected a close of /dev/random soon after the subsequent
read. Again, it is possible I simply did not capture enough of the output
of fs_usage, but I did have in excess of five seconds after this in the
output. Or possibly X11.app caches the descriptor after opening the file
for the first time.
Thanks for any help or suggestions,
mzs
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