02 Jun 2005

iPod Work

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I started working on a generic iPod device class that provides lots of information about the iPod and will work with Snorp’s ipod-sharp. It provides things like the name of the iPod (not the volume name, but the assigned name), the model/type (shuffle, regular, mini, photo), version info, serial numbers, capacity, used space, etc. It also supports safe ejection of the iPod. Initially I was doing this by just calling ‘eject’ on the device.

However, I decided I’d try doing this by making an ioctl call on the device. Not giving much thought to it, I came up with a few lines of code to eject a CD-ROM drive. It didn’t dawn on me until after the CD ejection code was working that the iPod is not a CD-ROM drive (it’s okay, you can smack me). It needs to be ejected as a SCSI device. The ioctl call[s] for this task are much more complicated (a structure must be passed to the device instead of a plain integer), and I’m not sure how to do this easily in C#. I’m not sure that it’s even worth it, and will probably go back to just execing ‘eject.’

Anyway, if anyone wants to eject a CD-ROM drive in C#, here you go. This may be useful for making basic ioctls in C# for other reasons. I’ve never seen an example of ioctl from C#, so maybe this is new.

<br /> using System;<br /> using System.Runtime.InteropServices;<br /> using Mono.Unix;</p> <p>public class SimpleEject<br /> {<br /> public static void Main(string [] args)<br /> {<br /> if(args.Length &lt;= 0) {<br /> Console.WriteLine(&#8221;Usage: mono-eject.exe [-t] <device>&#8220;);<br /> return;<br /> }</p> <p> string device = args[0];<br /> bool open = true;</p> <p> if(args.Length > 1 &#038;&#038; args[0].Equals(&#8221;-t&#8221;)) {<br /> device = args[1];<br /> open = false;<br /> }</p> <p> Console.WriteLine(Eject(device, open)<br /> ? String.Format(&#8221;Device {0} {1} successfully&#8221;, device,<br /> open ? &#8220;opened&#8221; : &#8220;closed&#8221;)<br /> : &#8220;Error ejecting device &#8221; + device);<br /> }</p> <p> [DllImport(&#8221;libc&#8221;)]<br /> static extern int ioctl(int device, EjectOperation request); </p> <p> private enum EjectOperation {<br /> Open = 0&#215;5309,<br /> Close = 0&#215;5319<br /> }</p> <p> public static bool Eject(string devicePath, bool open)<br /> {<br /> try {<br /> using(UnixStream stream = UnixFile.Open(devicePath,<br /> OpenFlags.O_RDONLY | OpenFlags.O_NONBLOCK)) {<br /> return ioctl(stream.Handle, open<br /> ? EjectOperation.Open<br /> : EjectOperation.Close) == 0;<br /> }<br /> } catch {<br /> return false;<br /> }<br /> }<br /> }<br /> </device>

And with that we have a simple Mono eject replacement for basic opening/closing CD-ROM trays. Woo-hoo!

3 Responses to “iPod Work”

  1. Jonathan Pryor says:
    June 2nd, 2005 at 10:40 am

    Mono.Unix.UnixStream implements IDisposable, so your Eject function could instead be:

    public static bool Eject(string devicePath, bool open)
    {
    try {
    using (UnixStream stream =
    UnixFile.Open(devicePath,
    OpenFlags.O_RDONLY |
    OpenFlags.O_NONBLOCK)) {
    return ioctl(stream.Handle, open
    ? EjectOperation.Open
    : EjectOperation.Close) == 0;
    }
    } catch {
    return false;
    }
    }

    - Jon

  2. Aaron Bockover says:
    June 2nd, 2005 at 1:05 pm

    Thanks! I hadn’t even looked into UnixStream that closely. First time I’ve ever used it. I’ll update the post to reflect the optimization. Best, Aaron.

  3. teknux says:
    April 8th, 2006 at 7:31 pm

    Hi Aaron,

    your article is very useful, I’m trying to write a lib for DVD access in c# (porting dvdcss and libdvdread), but I can’t find IOCTL codes. Where did you get the open/close codes?

    thank you, keep up the good work :)
    andrea - tek (italy)

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