Comments on: Controlling Input/Output of Device Drivers http://www.linux-mag.com/id/6206/ Open Source, Open Standards Sat, 04 Jul 2009 18:26:58 +0000 http://wordpress.org/?v=2.0.11 by: aholt http://www.linux-mag.com/id/6206/#comment-1202 Thu, 19 Jun 2008 14:46:09 +0000 http://www.linux-mag.com/id/6206/#comment-1202 Cirnath: I didn't think you were trying to be pedantic - it's a good point. Browsing through the header files SIOCGIFCONF is the only function I see that returns a list of interfaces and, as you correctly point out, it doesn't return down interfaces - if it doesn't have an IP address. A down interface with an IP address does show up (how weird is that?) I guess the behaviour of SIOCGIFCONF is down to the whim of the kernel developers. Cirnath: I didn’t think you were trying to be pedantic - it’s a good point. Browsing through the header files SIOCGIFCONF is the only function I see that returns a list of interfaces and, as you correctly point out, it doesn’t return down interfaces - if it doesn’t have an IP address. A down interface with an IP address does show up (how weird is that?) I guess the behaviour of SIOCGIFCONF is down to the whim of the kernel developers.

]]> by: cirnath http://www.linux-mag.com/id/6206/#comment-1195 Wed, 18 Jun 2008 17:14:55 +0000 http://www.linux-mag.com/id/6206/#comment-1195 Ok. I didn't know whether ioctl could be used in some other way to obtain the 'down' interfaces as well. That was more my reason for asking. I wasn't (intentionally) trying to be annoyingly pedantic. Ok. I didn’t know whether ioctl could be used in some other way to obtain the ‘down’ interfaces as well. That was more my reason for asking. I wasn’t (intentionally) trying to be annoyingly pedantic.

]]> by: aholt http://www.linux-mag.com/id/6206/#comment-1191 Mon, 16 Jun 2008 08:03:21 +0000 http://www.linux-mag.com/id/6206/#comment-1191 Yes you are correct, I probably should have made that clear in the article. I'm just really trying to demonstrate ioctls calls rather write a fully fledged "interface discovery" utility. If I were, I'd probably just get them out of /proc/net/dev. But thanks for the clarification. Yes you are correct, I probably should have made that clear in the article. I’m just really trying to demonstrate ioctls calls rather write a fully fledged “interface discovery” utility. If I were, I’d probably just get them out of /proc/net/dev. But thanks for the clarification.

]]> by: cirnath http://www.linux-mag.com/id/6206/#comment-1190 Sun, 15 Jun 2008 17:28:58 +0000 http://www.linux-mag.com/id/6206/#comment-1190 Just to be clear... the show_ints code can only see interfaces which are in an 'up' state. If you were truly doing interface discovery (i.e. for an installer or some such) and no interfaces are in a configured state, what would the code look like to identify the interfaces? Just to be clear… the show_ints code can only see interfaces which are in an ‘up’ state.

If you were truly doing interface discovery (i.e. for an installer or some such) and no interfaces are in a configured state, what would the code look like to identify the interfaces?

]]> by: aholt http://www.linux-mag.com/id/6206/#comment-1184 Fri, 13 Jun 2008 08:27:22 +0000 http://www.linux-mag.com/id/6206/#comment-1184 Thanks for the feedback Rakesh. The article appeared in Linux Magazine a couple of months ago, so they are responsible for publishing the article on-line. To save space the editor took the code listings out and put them on the web. I don't know why the URL doesn't work, but I've let them know - hopefully it will be fixed soon. However, as an alternative, I've put the tar file here: http://agholt.googlepages.com/ioctl.tar.gz Thanks for the feedback Rakesh. The article appeared in Linux Magazine a couple of months ago, so they are responsible for publishing the article on-line. To save space the editor took the code listings out and put them on the web. I don’t know why the URL doesn’t work, but I’ve let them know - hopefully it will be fixed soon. However, as an alternative, I’ve put the tar file here: http://agholt.googlepages.com/ioctl.tar.gz

]]> by: rakesh uv http://www.linux-mag.com/id/6206/#comment-1182 Fri, 13 Jun 2008 04:11:13 +0000 http://www.linux-mag.com/id/6206/#comment-1182 Hi Alan, That was a wonderful and simple explaination, Keep it UP. Please Do Post Such Articles frequently. There one problem with one of the links provided in the article,http://www.linux-mag.com/code/08.03.ioctl.tar. Thank You Hi Alan,
That was a wonderful and simple explaination, Keep it UP.
Please Do Post Such Articles frequently.
There one problem with one of the links provided in the article,http://www.linux-mag.com/code/08.03.ioctl.tar.

Thank You

]]> by: mohamedhagag http://www.linux-mag.com/id/6206/#comment-1179 Thu, 12 Jun 2008 16:04:32 +0000 http://www.linux-mag.com/id/6206/#comment-1179 nice i hope that we can see more in depth articles like this, Ph. Alan ;) please do it frequently :) . nice i hope that we can see more in depth articles like this, Ph. Alan ;) please do it frequently :) .

]]> by: djeepp http://www.linux-mag.com/id/6206/#comment-1174 Thu, 12 Jun 2008 15:07:18 +0000 http://www.linux-mag.com/id/6206/#comment-1174 I guess a prerequisite to reading this article would be a basic understanding of coding in c of which I have none of. This stuff is way over my head. I guess a prerequisite to reading this article would be a basic understanding of coding in c of which I have none of. This stuff is way over my head.

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