Thread

1. DB-shell connect

   Gregory Holston <holston@itd.nrl.navy.mil> — 1998-07-01T14:13:26Z

   Can an SQL database (PostgreSQL) be connected to shell in a way that if
   a directory is changed on shell it will update the database with the
   changes?  If so how?
   A prompt reply would be appreciated.
   
   Thank in advance,
   Greg
   
   
   

2. Re: [HACKERS] DB-shell connect

   Bruce Momjian <maillist@candle.pha.pa.us> — 1998-07-01T15:30:25Z

   > 
   > Can an SQL database (PostgreSQL) be connected to shell in a way that if
   > a directory is changed on shell it will update the database with the
   > changes?  If so how?
   > A prompt reply would be appreciated.
   > 
   > Thank in advance,
   > Greg
   > 
   > 
   > 
   
   That is tough.  It is normally very difficult to trigger 'anything' if
   someone changes a directory in their shell.  It would have to be
   triggered in the kernel, and out of the kernel up to an SQL process. 
   Very tough.
   
   Their are Unix tools that monitor the everyone's current directory, but
   they are polling tools, not some automatic thing on every directory
   change.
   
   It is the chdir() kernel call you want to trigger on.
   
   -- 
   Bruce Momjian                          |  830 Blythe Avenue
   maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
     +  If your life is a hard drive,     |  (610) 353-9879(w)
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3. Re: [HACKERS] DB-shell connect

   Brian E Gallew <geek+@cmu.edu> — 1998-07-01T15:48:21Z

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   > Can an SQL database (PostgreSQL) be connected to shell in a way that if
   > a directory is changed on shell it will update the database with the
   > changes?  If so how?
   > A prompt reply would be appreciated.
   
   On most *nix systems, this feature is called "auditing."  You may not
   realize this, Greg, but what you *really* want to do is:
   1)  Turn on auditing (if auditing is not available, try new OS).
   2)  Write a script which grovels through the audit log periodically
   and inserts the appropriate rows in your database.
   
   Actually, there *is* another alternative:
   1)  Make everybody's shell /bin/bash (or translate the following)
   2)  Create the following alias in /etc/profile
   alias cd="\cd $1;psql database -c \"insert into cdtable values (\'$PWD\');\\g\""
   3)  Hope your users don't unalias that.
   
   BTW, the alternative offered above is BAD:
   1)  Every cd invokes psql == suckful performance.
   2)  Can be trivially broken by users.
   3)  Will not notice chdir()'s in shell-scripts and executables.
   
   An improvement can be attained by grabbing the source to bash, and
   modifying both the init code (attach to database) and the "cd" code
   (insert row, COMMIT).  However, this shell should *never* be used by
   root (never futz with the root shell) or PostgreSQL superuser
   (chicken-and-egg).
   
   - -- 
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