On Fri, 18 Jun 2010 23:16:29 +0530 Prashant Shah wrote:
> Hi,
>
> Below is a small module that I was trying out (code at the end of message)
>
> This module creates a file called /proc/jiffies that adds a message to
> the log file using printk and shows the current jiffies value to the
> user when it is read.
>
> If I cat the /proc/jiffies file once, in the dmesg log there are three
> entries. The function create_proc_read_entry() is calling the
> my_proc_read() thrice.
>
> o/p :
> [ 997.261195] ******** Reading jiffies files *********
> [ 997.261205] ******** Reading jiffies files *********
> [ 997.261233] ******** Reading jiffies files *********
Is there a question here??
Here's what I would try: in my_proc_read(), printk the values of
off and count.
> -------------- module code ---------------
>
> #include <linux/module.h>
> #include <linux/init.h>
> #include <linux/jiffies.h>
> #include <linux/delay.h>
> #include <linux/proc_fs.h>
>
> #define SUCCESS 0
> static char modname[] = "jiffies";
>
> static int my_proc_read(char *buf, char **start, off_t off,
> int count, int *eof, void *data)
> {
> printk("******** Reading jiffies files *********\n");
> return sprintf(buf, "jiffies = %lu\n", jiffies);
> }
>
> static int __init mod_entry(void)
> {
> printk(KERN_INFO "***** START *******\n");
> create_proc_read_entry(modname, 0, NULL, my_proc_read, NULL);
> return SUCCESS;
> }
>
> static void __exit mod_exit(void)
> {
> printk("******** END *********\n");
> remove_proc_entry(modname, NULL);
> return;
> }
> MODULE_LICENSE("GPL");
> module_init(mod_entry);
> module_exit(mod_exit);
> --
---
~Randy
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