hello,
I have a /proc file kernel module with its proc
read function as
static char mybuf[1024];
ssize_t my_file_read(struct file *filp, char *buf,
size_t count, loff_t *ppos)
{
printk("Reading a from a /proc file....\n");
static int b_read = 0;
int len = strlen(mybuf);
if (len == 0 || b_read) {
b_read = 0;
return 0;
}
if (len > count - 1)
len = count - 1;
copy_to_user(buf, mybuf, len);
put_user(0, &buf[len]);
++len;
b_read = 1;
return len;
}
when i strace cat /proc/my_file i found message
printing twice
Reading a from a /proc file....
Reading a from a /proc file....
Why that happening?
Also i check by writing to it as cat >
/proc/my_file
and got single result for write function call not
twice as for read.
regards,
cranium
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