CODEWITHSUNDEEP
clinuxtimerlinux-kernel
David
David

Reputation: 229

Write to proc in a kernel module which uses also a character device

I have a kernel module which implements a timer and it works. At the same time I am able to create a new kernel module to write and read from proc. What I don't understand is how to combine the two operations in the same kernel module.

My application works in this way. A user program writes to the kernel module a number n which is used to create a timer that will expire in n milliseconds. To do so I implemented the write and read functions and I linked them to the struct file_operations which I use in the init function to register my character device (the timer).

Now for the proc file I need to declare a write and read function as well which should handle the requests from the user program. This is what confuses me, I cannot understand how to combine everything together.

Upvotes: 0

Views: 755

Answers (1)

Sasi V
Sasi V

Reputation: 1094

As Tsyvarev mentioned use different file_operations

static struct proc_dir_entry *procfs;

static const struct file_operations proc_fops = {
 .owner = THIS_MODULE,
 .open  = open_proc_fn,
 .read  = read_proc_fn,
};

static const struct file_operations char_fops = {
 .owner = THIS_MODULE,
 .open  = open_char_fn,
 .read  = read_char_fn,
 .write = write_char_fn, 
};


int __init init_mod (void) {
   procfs = proc_create("filename", 0, NULL, &proc_fops);
   if(!proc)
       return -1;
   <Register char device with &char_fops >
   return 0;
}

Upvotes: 1

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