Gentoo Archives: gentoo-dev

From: Radoslaw Stachowiak <rstachowiak@×××××.com>
To: Paul de Vrieze <pauldv@g.o>
Cc: gentoo-dev@l.g.o
Subject: Re: [gentoo-dev] small dispatch-conf patch, WAS: extension of etc-update
Date: Thu, 12 Aug 2004 07:35:46
1 > > Because You have to calculate them for all files, and _before_
2 > > emerge. Also such database has to be regularly updated (sth like
3 > > eupdate/esearch).
4 >
5 > Hmm, I thought that things were only calculated/compared for those
6 > configuration files which might involve updating (those that get ._cfg etc)
8 yes, you are right. i was talking only about CONFIG_PROTECT files.
9 the biggest problem (as I see it) is that it requires special
10 maintenance and overhead to gather this data constantly. of course
11 computational overhead (due to use of md5) is negligible.
13 > > Not that Im sure of time approach, but Could You show one real word
14 > > scenario when ctime/mtime comparison would fail /while md5sum does
15 > > not/ ?
16 >
17 > In cases of clock skew or toying with touch. Esp. the clock skew thing is not
18 > that uncommon.
20 Hmm, good point, but skew must be backwards, and not only it have to
21 be big enough (which is hard to achieve because every second after
22 package installation time, this necessary-for-failure time gap is
23 growing), but it has to be present at the time you hand modify
24 config-file-to-be-lost. i think its almost impossible.
26 Of course ntp time synchronisation would solve this.
28 As to touch. normal touch usage don't put You at risk because file
29 will have mtime > ctime so its not problem. special touch usage
30 (modify mtime to value other than current) is so rare that have to be
31 use for some purpose (eg for mark file to be overwritten by newer
32 update, even ifits modified) which is justified use for me.
34 Files overwritten are backed up by dispatch, so even if sth was
35 screwed up, you can get previous file from dispatch backup.
37 Im going to use it on some machines this month, and will let You know
38 what happened :)
40 --
41 radek@g.o.
43 --
44 gentoo-dev@g.o mailing list