Letters

LJ readers sound off.
Zaurus Fans Unite

Excellent article [“Must-Have Zaurus Hardware and Software”, LJ, January 2003]! Very informative and a lot of detail. I have just bought my Zaurus, and I downloaded a lot of utilities and was able to set my Zaurus's configuration with the help of Guylhem Aznar's article. Thank you.

—Vinh Duong

Be Careful with ptrace

In “Playing with ptrace, Part II” [LJ, December 2002], Pradeep Padala talked about injecting code into a process and finding some “free space” to put it in to. It's worth noting that the space referred to is not really “free”; it's usually either the cleared space used for global storage in the executable and its shared libraries or the C library's heap storage area. In any case, writing over this data and not restoring it before allowing the execution to continue (as may seem reasonable at first) could cause all sorts of weird behaviour, including program crashes.

—Shaun Clowes

FreeS/WAN Updates

Just got my January 2003 issue of LJ and was quite surprised to see a FreeS/WAN article included—nice work! I was really happy to see you used the RSASigs in the examples instead of preshared secrets, a welcome change from the usual and insecure examples I've read in the past. I maintain www.freeswan.ca, an alternate source of information, patches and prepatched versions of FreeS/WAN for interoperation with many devices. Freeswan.org now ships RPMs for Red Hat 7.x and 8.x for all kernel combinations. These include only the ipsec.o modules and user-land tools and don't replace your vmlinuz and grub/lilo configs. Folks should update to 1.99, as there was a serious denial-of-service flaw that is now fixed.

—Ken Bantoft

Mick's reply: Thanks very much for your suggestions. Part II appeared in the February 2003 issue, and I doubt this is the last I'll write on the subject!

Surprising Our Readers...with Quality

As a long-term LJ reader (fourth year), I am really surprised about the great January 2003 issue—it covers all the stuff that I am interested in without even knowing about it. The GCJ, Screen and DDD/quicksort articles shed more light into the daily use of our beloved Linux platform. Please keep us informed about developments in compilers, debuggers and other development tools to make us more effective in developing new stuff. Keep up the good work.

—Raphael Arlitt, Germany

make penguins && make party

What LUG meeting or BOF session would not be enhanced by penguin canapés and an igloo cheeseball? We humbly submit pseudo-code for building same and an image as proof that it's working code.

Ingredients:

2 packages cream cheese1 cheeseball1 can large black olives, pitted1 can small black olives, pitted1 carrot1 packages toothpicks with yellow or orange fringecrackers1 tin kippered herring (optional symbolic offering to penguins)

#!/bin/bash
while hungry;
do (\
        cut_cream_cheese_into_strips_and_cover_cheeseball;\
        make_igloo_entrance_tunnel_from_cream_cheese_strip;\
        use_toothpick_to_sculpt_snow_block_seams;\
        peel_carrot_with_vegetable_peeler;\
        cut_carrot_into_coin-sized_slices;\
        cut_slender_wedge_from_each_carrot_slice_and_reserve_for_beak;\
        slit_each_large_olive_and_stuff_with_cream_cheese;\
        puncture_each_small_olive_and_insert_carrot_wedge_beak;\
        skewer_small-olive_head_large-olive_torso_and_carrot-slice_feet_with_toothpick;\
        arrange_olive_penguins_about_cheeseball_igloo_on_serving_dish;\
        arrange_crackers_on_serving_dish_or_nearby;\
        serve);
done

Herring also can be served to set the scene. Herring are one of two things that make penguins contented. This recipe is a clean-room implementation developed by reverse engineering based on a study of olive penguins and a cheeseball igloo served at a party. We hope the process is not patented. In any case, we assert that the recipe is our own work, and we release it under the terms of the GNU Free Documentation License.

—Michael Callaham [penguins] and Jennifer Gentry [igloo]

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