Messages in this thread | | | From | Tim Jansen <> | Subject | /proc format (was Device Registry (DevReg) Patch 0.2.0) | Date | Wed, 25 Apr 2001 20:55:56 +0200 |
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On Wednesday 25 April 2001 19:10, you wrote: > The command > more foo/* foo/*/* > will display the values in the foo subtree nicely, I think.
Unfortunately it displays only the values. Dumping numbers and strings without knowing their meaning (and probably not even the order) is not very useful.
> Better to factor the XML part out to a userspace library...
But the one-value per file approach is MORE work. It would be less work to create XML and factor out the directory structure in user-space :) Devreg collects its data from the drivers, each driver should contribute the information that it can provide about the device. Printing a few values in XML format using the functions from xmlprocfs is as easy as writing proc_printf(fragment, "<usb:topology port=\"%d\" portnum=\"%d\"/>\n", get_portnum(usbdev), usbdev->maxchild);
Extending the devreg output with driver-specific data means registering a callback function that prints the driver's data. The driver should use its own XML namespace, so whatever the driver adds will not break any (well-written) user-space applications. The data is created on-demand, so the values can be dynamic and do not waste any space when devreg is not used.
The code is easy to read and not larger than a solution that creates static /proc entries, and holding the data completely static would take much more memory. And it takes less code than a solution that would create the values in /proc dynamically because this would mean one callback per file or a complicated way to specify several values with a single callback.
bye...
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