init: API

[Avi Kivity]

Kenneth Porter wrote:

>
> So far all init scripts are written in Bash, and the ones I'm familiar 
> with use simple variable=value pairs, using Bash syntax. Is that 
> sufficient? What can't be expressed in that way?

hierarchical configuration. multiple instances of the same service. most 
complex services have their own config files so the complexity is pushed 
there.

>
> The hierarchical configuration I've seen has been in the networking 
> scripts, and is encoded in the filesystem, using filenames or 
> directory trees to represent configuration nodes. What's the drawback 
> of that, if any?
>
dependencies not expressed explicitly, messy config files.

for example, my ppp0 depends on eth0, and a potential vpn would depend 
on ppp0. there is no way to express that with the current syntax. there 
is special support for bonding, etc.

also it's horribly slow:

[root at blast ~]# time /sbin/service network restart
Shutting down interface eth0:                              [  OK  ]
Shutting down loopback interface:                          [  OK  ]
Bringing up loopback interface:                            [  OK  ]
Bringing up interface eth0:
Determining IP information for eth0... done.

                                                           [  OK  ]

real    0m11.043s
user    0m0.656s
sys     0m0.776s

1.4 seconds of cpu time to issue a few ioctls and send a couple of 
packets (2.4GHz Athlon64).

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.