/etc/magic entry for GIFs

Jay Kozak

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Apr 26, 1993, 3:07:01 PM4/26/93

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More and more of my users are discovering GIF's for backgrounds on their
X-terminals. We were having the problem of everybody putting GIF's in their
home directory. A policy has since been implemented. Fighting GIF's seemed
like an endless battle. We know have a mounted directory that all users
can get GIF's from. They can also submit GIF's to a public directory. The
GIF's are then reviewed and if deemed non-offensive to anyone they get put
in the GIF area. I still have users that keep them in their home directories.
I would like to find all these files to warn the users and if they don't take
heed to the warning delete the files. I don't feel I have the right to snoop
around in their home directories. And with over 500 users I wouldn't have the
time. Does anybody have /etc/magic entries for GIF's. With this, I could just
do a find at night. Please email any responses.

Thanks
Jay

Jay Kozak Motorola CIG
System Administrator Rm 3082
koz...@man.rtsg.mot.com 1501 W. Shure Drive
(708) 632-7550 Arlington Heights, IL 60004

John Hascall

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Apr 26, 1993, 10:27:26 PM4/26/93

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--
John Hascall ``An ill-chosen word is the fool's messenger.''
Systems Software Engineer
Project Vincent
Iowa State University Computation Center + Ames, IA 50011 + 515/294-9551

R. Stewart Ellis

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Apr 27, 1993, 7:31:07 AM4/27/93

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ko...@rtsg.mot.com (Jay Kozak) writes:

>Thanks
>Jay

I have added an entry for GIF87 to our /etc/magic file:

0 string GIF87 Gif87 Graphic file

To figure out what the signature is use a binary viewer (I frequently use
emacs) to scan the first part of the file. Gif is easy because the
signature is at the top.

--
___________________
R.Stewart(Stew) Ellis, Assoc.Prof., (Off)313-762-9765 / _____ ______
Humanities & Social Science, GMI Eng.& Mgmt. Inst. / / / / / /
Flint, MI 48504 el...@nova.gmi.edu /________/ / / / /

sn

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Apr 27, 1993, 9:56:54 AM4/27/93

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el...@nova.gmi.edu (R. Stewart Ellis) writes:

>ko...@rtsg.mot.com (Jay Kozak) writes:

>>time. Does anybody have /etc/magic entries for GIF's. With this, I could just
>>do a find at night. Please email any responses.

>>Thanks
>>Jay

>I have added an entry for GIF87 to our /etc/magic file:

>0 string GIF87 Gif87 Graphic file

There is another GIF standard (GIF89) that you might want to include also.

-Sven

Hal Joshua Eisen

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Apr 27, 1993, 1:05:28 PM4/27/93

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You'll need two entries in /etc/magic:

0 string GIF87 Gif87 graphics file
0 string GIF89 Gif89 graphics file

To determine which strings to match, I like to use "od -c <filename> | head".

Hal

--
Hal J Eisen, TMWTMOASS / ei...@cs.jhu.edu (internet) / eisen@jhuigf (BITNET)
"Violence is the last refuge of the incompetent" --Salvor Hardin
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bus error (passengers dumped)

Elizabeth Schwartz

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Apr 27, 1993, 6:27:48 PM4/27/93

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In my opinion it is more fair to enforce disk quotas than to look into
the contents of users files. We give students two areas: a home
directory which is permanent and a course directory which is
temporary, and we limit their storage on the home directory to one
meg. It is up to them what they choose to do with that space, and
separating project space from personal space allows us to allocate the
maximum possible space for projects.
In a business environment, you could separate the production and
scratch areas from the personal areas. If you have a space problem in
one area, deal with that area.
My two cents...

Betsy

Policy group disclaimer:

This posting represents my personal opinion at the time of posting.
I am using the net as a personal learning tool: nothing I write is
official policy unless explicitly labelled as "official" policy.
Please do not repost or anthologize this post without my permission.
thanks, Betsy.
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System Administrator Internet: bet...@cs.umb.edu
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John Hascall

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Apr 27, 1993, 10:21:22 PM4/27/93

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}In article <kozak.735851221@taupe> ko...@rtsg.mot.com (Jay Kozak) writes:

[...wants magic file lines for gifs...]

In article <C64Et...@news.iastate.edu> jo...@iastate.edu (John Hascall) writes:
[...somehow I managed to post no useful information at all in attempt 1...]

So, in penance, here are some entries from our file (it is Ultrix, so
the format is a little odd, but...):

0 string ^GIF\\%...\\% 7,21 GIF (%s) image
>6 short >0 7,21 (%d
>8 short >0 7,21 x %d)
0 short 0x4949 7,22 TIFF
>2 short >0 7,22 (v%d) image
0 long 0xffd8ffe0 7,23 JPEG image (big endian)
0 long 0xe0ffd8ff 7,24 JPEG image (little endian)
0 short 0x02f7 7,26 DVI
>16 string ^\\%[A-Za-z0-9.: ]*\\% 7,26 (%s)

John