- Roundtable - muug.ca

Protip: dealing with remote terminals, and /proc/pid/environ
by Scott Balneaves 12 Mar '07

12 Mar '07

Hello all Bumped into something I needed to do this morning, thought others may be interested. I needed to get an accurate count of how many 15 inch monitors I had on my LTSP network. One can, of course, get this from xdpyinfo, but I can't ssh into clients to do this. What to do, what to do... Well, of course, what I need to do is set my $DISPLAY and $XAUTHORITY environment variables correctly, so I can run xdpyinfo. But, how to find out who's on what terminal? Well, since everyone runs metacity as a window manager: pgrep metacity returns a list of process id's. From there, we can look in /proc/<pid>/environ, and get some more info! But hold on: cat /proc/3660/environ returns: SSH_CLIENT=192.168.0.229 443422USER=foobarMAIL=/var/mail/foobarGNOME_KEYRING_SOCKET=/tmp/keyring-awvD15/socketSSH_AGENT_PID=3510 etc. Environment variables are null terminated! So, how to get around that? As usual, there's a quick easy way to do it: tr to the rescue: cat /proc/3660/environ | tr '\0' '\n' SSH_CLIENT=192.168.0.229 4434 22 USER=foobar MAIL=/var/mail/foobar GNOME_KEYRING_SOCKET=/tmp/keyring-awvD15/socket etc. Hey! Fit for using with eval! Here's the whole script, just for fun. #!/bin/bash for PROC in $(pgrep metacity); do eval $(cat /proc/$PROC/environ | tr '\0' '\n' | grep SSH_CLIENT | awk '{print $1}') eval $(cat /proc/$PROC/environ | tr '\0' '\n' | grep USER) export DISPLAY=$SSH_CLIENT:6 export XAUTHORITY=/usr/legal/home/$USER/.Xauthority echo -n ${USER} xdpyinfo | grep dimension done Hope someone finds this useful. Scott -- Scott L. Balneaves | "Let us endeavor so to live that when we come to die Systems Department | even the undertaker will be sorry." Legal Aid Manitoba | -- Mark Twain, "Pudd'nhead Wilson's Calendar"

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syscall mapping in userland.
by Sean Cody 12 Mar '07

12 Mar '07

I'm implementing a basic system call to get a handle on how. Now I build it into a kernel fine and call it via 'syscall (__NR_foo)'; which gives the desired output. Now I'm trying to get the stub working so I can call in userland via 'foo()'.. Since when compiling the kernel my foo.h wasn't put in /usr/include/ linux/foo.h I copied it there myself. The contents are below: #include <linux/unistd.h> _syscall0(int,foo); /* no parameters. */ Now if I complile a test userland app trying to reference foo.h I get. gcc -o t test.c In file included from test.c:2: /usr/include/linux/foo.h: error: expected declaration specifiers or '...' before 'foo' /usr/include/linux/foo.h: warning: data definition has no type or storage class This lends me to believe that either I'm using _syscall0 wrong or it is broken (since I can invoke the system call by it's number). I've grepped through the kernel source and found lots of references (specifically x64 ones) for stub_syscallX but nothing matching what has been described (aside from the macro definitions of course). I've also ready through syscall(2) man page and it states I'm using it right as does the macro itself in include/asm/unistd.h I've also tried going around the macro by doing it manually (ie. implement the macro with my values instead of the 'macro parameters'). Does anyone see anything obviously wrong with the above or have any links to relevant documents that detail syscall creation on a kernel newer than 2.4 (lots I've found so far are 2.4 centric and there have been significant layout changes since)? -- Sean

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Xen and Windows
by Bill Reid 12 Mar '07

12 Mar '07

I got Win XP running under Xen on a Intel Dual Core CPU which supports VT technology. I am using FC6. Fedora has a script for creating domains and a GUI for managing the domains. It works very well. The one show stopper is that during the Win XP install you have to press F5 when the screen comes up saying "Press F6 for additional drivers". After pressing F5 you select "Standard PC..." -- Bill

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Linux install on a Compaq Presario
by greg.carter＠orf.org 12 Mar '07

12 Mar '07

Hello Round Table, I have stated to do an install of Ubuntu 6.10 on a Compaq Presario R3000 series and have encountered some known issues such including the Broadcom wireless and possibly the Alps mouse pad. I have partitioned the HD but am stalled with the programming required to work around the Broadcom device. I understand the Presario can be made to work but it takes expertise beyond my ability. Is there anyone in Winnipeg who might be interested in this project...? Thanks much, Greg Carter

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infrastructure problem?
by millward 11 Mar '07

11 Mar '07

Could anyone define for me, in IT terms, what an infrastructure problem is? Revenue Canada is now in such a mess it can't even process mail in tax forms. They claim it is an "infrastructure problem". Duh? Has anyone any idea what hardware / software they depend upon? I'd like to have some idea what went wromg. After all, as a tax payer, I'm paying for this mess. And so are you!

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Ubuntu networking problem
by Kevin McGregor 09 Mar '07

09 Mar '07

I am trying to move a Ubuntu Linux 5.10 server from a physical machine to a virtual machine running under VMware Server. I have managed to duplicate the disk and get it to boot properly, but eth0 does not end up with an IP address. The proper module for it is pcnet32, and it shows up in `lsmod`, but aside from that, nothing. ifconfig shows the interface is there. What have I missed?

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Questions about dig
by John Lange 07 Mar '07

07 Mar '07

Does anyone know if there is a way to tell if dig had to perform a recursive query to return an answer? This seems like it would be an obvious thing to indicate in a result but it doesn't seem to show up anyplace. So for example, in the query: # dig @localhost www.somedomain.com I'd like to know: - did localhost consider itself the authorative answer? - if not, did it return the result from local cache? - or, did it recursively discover the result from out on the net? - If it recursively discovered the answer, which server did it query to get the answer? In my testing, I performed some queries where I knew before hand the answers to the above questions and then compared the results from dig and I could find no definitive way to tell the difference in the results. Any dig masters want to give me some tips? John

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MUUG Meeting, March 13, 7:30pm -- Sun's Zettabyte File System
by gedetil＠cs.umanitoba.ca 07 Mar '07

07 Mar '07

The Manitoba UNIX User Group (MUUG) will be holding its next monthly meeting on Tuesday, March 13. The meeting topic for this month is as follows: Sun's Zettabyte File System Shawn Wallbridge will be presenting on ZFS, a new filesystem that was introduced with Solaris 10 update 2. Some have called it the most advanced file system ever; it certainly has a lot of very advanced features. Shawn will discuss ZFS, its features and benefits, and how it has changed how Frantic Films looks at storage. The group holds its general meetings at 7:30pm on the second Tuesday of every month from September to June. (There are no meetings in July and August.) Meetings are open to the general public; you don't have to be a MUUG member to attend. ********************************************************************** Please note our meeting location: The IBM offices, at 400 Ellice Ave. (between Edmonton and Kennedy). When you arrive, you will have to sign in at the reception desk, and then wait for someone to take you (in groups) to the meeting room. Please try to arrive by about 7:15pm, so the meeting can start promptly at 7:30pm. Don't be late, or you may not get in. (But don't come too early either, since security may not be there to let you in before 7:15 or so.) Non-members may be required to show photo ID at the security desk. Limited parking is available for free on the street, either on Ellice Ave. or on some of the intersecting streets. Indoor parking is also available nearby, at Portage Place, for $3.00 for the evening. Bicycle parking is available in a bike rack under video surveillance located behind the building on Webb Place. ********************************************************************** For more information about MUUG, and its monthly meetings, check out their Web server: http://www.muug.mb.ca/ Also note that MUUG maintains two mailing lists, called "muug-announce" and "roundtable". If you're not already on these lists, we encourage you to subscribe now: http://www.muug.mb.ca/mailman/listinfo/ The "muug-announce" list is used for monthly meeting announcements (such as this one) as well as other important announcements of interest to MUUG members. The "rountable" list is meant to be a forum for follow-ups to topics discussed at the meetings, or for round-table-style discussion on other topics that come up between meetings. Of course, for this to be effective, we need to reach a certain critical mass. So, please subscribe, and stay involved! -- Gilbert E. Detillieux E-mail: <gedetil(a)muug.mb.ca> Manitoba UNIX User Group Web: http://www.muug.mb.ca/ PO Box 130 St-Boniface Phone: (204)474-8161 Winnipeg MB CANADA R2H 3B4 Fax: (204)474-7609

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OQO (ver2) or the Sony UX
by Montana Quiring 06 Mar '07

06 Mar '07

Sorry, I know this isn't exactly a *NIX based question but, which ultra portable would you guys recommend for a non-geek, business type? OQO2: http://www.dynamism.com/oqo02/main.shtml Sony Viao UX: http://www.dynamism.com/ux/main.shtml -Montana

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Seeking Perl CGI / XML programmer for small job
by Adam Thompson 06 Mar '07

06 Mar '07

I'm looking for some names to pass on... A local company is looking for someone to complete the development of a software system that is already partially designed and implemented. The software is a CGI interface into a database for custom XML transactions. Some business logic exists, but not much. Total project size (including parts already completed) was estimated at 65 - 100 hours. Said company requires an initial (re?)implementation to be completed ASAP, probably about 30-40hrs of work. Code must be clean and easily readable, and well documented, as it will be used as the starting point for future variants (with different XML-speaking trading partners). If you can code XML in Perl (or possibly PHP), against a MySQL database, and are interested in this small opportunity, please contact me. (Sorry, Python and Ruby are out - this has to be hosted in an old version of ActivePerl / ActivePHP. You can argue that point later if necessary.). Thank you for your time, -Adam Thompson athompso(a)athompso.net

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