Highlight feature of DP: trace mode

Hi all,

This is the first of a series of two e-mails about highlight features  
of DarwinPorts.

I would like to encourage all developers and users to use the -t  
option of port(1). This option enables the trace mode.

The synopsis is very easy:

sudo port -t install foo

The trace mode changes two things:
- the installed software cannot write outside clearly defined bounds.  
In particular, the software is not able to write anything in /opt/ 
local or /usr/local. The files are copied during the activation  
phase. Any attempt to write where forbidden yields a warning on the  
console.
- it automatically detects undeclared dependencies by noticing what  
port the software refers to when being configured, built and installed.

By using the trace mode, developers can ensure that they properly  
patched the software to make it write into the destroot.

By using the trace mode, users can ensure that their installation  
won't be damaged by a file installed by a port outside the destroot.

The trace mode in 1.3.1 forbids file creations, modifications and  
deletions as well as directory creations (outside the sandbox). The  
version in HEAD additionally forbids file renaming and directory  
deletion.

Paul
-- 
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Mobile. Sans baignoire fixe.
http://www.kallisys.com/
http://www-poleia.lip6.fr/~guyot/