Re: Immutable flag and packages

[bear@coyotesong.com]

> > As a trivial example, it would be reasonable to have /etc/fstab
> > marked immutable, while /etc/mtab would be mutable.  
> 
> To remove or clear the flag you need not just to be superuser, but to be
> running at securelevel 0, which normally requires a reboot to single user 
> mode.

During lunch, I verified that I could create a file, mark it immutable,
and not force a modification even as root.  I then cleared the immutable
bit and nuked the file.   The exact commands ran something like:

 # touch /tmp/foobar
 # chattr +i /tmp/foobar
 # rm -rf /tmp/foobar
   (failed)
 # vi /tmp/foobar
   :w!
   (unable to write file)
 # chattr -i /tmp/foobar
 # rm -rf /tmp/foobar
   (success)

I'm currently running 1.3, although I plan to upgrade to hamm within the 
next few days.  In fact, I was downloading some binary files at the time, 
so I *know* that my system continued to function in its normal manner.

I hate to ask a stupid question, but are you sure you aren't thinking
about mounting an entire filesystem as "read-only", not just marking
a single file (or collection of files) as "immutable" under the ext2
extentions? 

On a related note, the chattr man page mentions the possibility of
specifying a "version number" for a file.  I couldn't get that to
work, possibly because I tried 1.2 instead of an integerized form of
it, but this introduces interesting possibilities for package writers. :-)

Bear Giles
bear@coyotesong.com


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