How to store an array on sysfs in Linux kernel module?

Question

I am writing Linux Kernel module, where I'm creating some sysfs files to store variables.

But I need to implement arrays, something like:

struct ats {
   struct attribute attr;
   unsigned long value[5];
};

struct ats m_ats = {
   .attr.name="m_ats",
   .attr.mode = 0644,
   .value[0] = 0,
   .value[1] = 0,
   .value[2] = 0,
   .value[3] = 0,
   .value[4] = 0,
};

Is there a way to do that? How would be the show, store, module_init, module_exit functions?

are you asking if there is a way to point to functions? "How would be the show, store, module_init, module_exit functions?" — Babbleshack
– Babbleshack, Commented Feb 4, 2014 at 12:21
no, I'm asking how to implement these functions. What difference exist between normal variable store on sysfs and array one. — 2rdv1
– 2rdv1, Commented Feb 4, 2014 at 12:24

Federico · Accepted Answer · 2014-02-05 10:31:48Z

3

You have to do it manually. You can use sscanf on the incoming string, parse the input and store each value in the array slot. Something like this:

sscanf(input_string, "%d %d %d", value[0], value[1], value[3])

answered Feb 5, 2014 at 10:31

Federico

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2 Comments

2rdv1 Over a year ago

Isn't there another way? for example, the loopN files on /sys/block : loop0 , loop1 and so on, are all created by hand?

Federico Over a year ago

they are created automatically when a loop block device occur. But this is not what you are asking for. You asked for attributes, and in your example you are talking about blocks devices

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