On Wed, Sep 15, 2010 at 5:39 PM, Tayade, Nilesh <nilesh.tay...@netscout.com>wrote:
> Can't it be because you are using size = 1byte in copy_from_user? Make it > 'count'. > > After your suggestion I tried changing > --------------------------------------------------------- > > > #include <linux/init.h> > #include <linux/module.h> > #include <linux/kernel.h> /* printk() */ > #include <linux/slab.h> /* kmalloc() */ > #include <linux/fs.h> /* everything... */ > #include <linux/errno.h> /* error codes */ > #include <linux/types.h> /* size_t */ > #include <linux/proc_fs.h> > #include <linux/fcntl.h> /* O_ACCMODE */ > #include <asm/system.h> /* cli(), *_flags */ > #include <asm/uaccess.h> /* copy_from/to_user */ > > > > > /* Declaration of memory.c functions */ > int bond_open(struct inode *inode, struct file *filp) { return 0;}; > int bond_release(struct inode *inode, struct file *filp){ return 0;}; > ssize_t bond_read(struct file *filp, char *buf, size_t count, loff_t > *f_pos) > { > > /* Transfering data to user space */ > copy_to_user(buf,bond_buffer,1); > > > /* Changing reading position as best suits */ > if (*f_pos == 0) { > *f_pos+=1; > return 1; > } else { > return 0; > } > }; > > > > > ssize_t bond_write(struct file *filp, char *buf, size_t count, loff_t > *f_pos) > { > > > char *tmp; > > > tmp=buf+count-1; > copy_from_user(bond_buffer,tmp,1); > return 1; > } ; > void bond_exit(void); > int bond_init(void); > > > /* Structure that declares the usual file */ > /* access functions */ > struct file_operations bond_fops = { > read: bond_read, > write: bond_write, > open: bond_open, > release: bond_release > }; > > > /* Global variables of the driver */ > /* Major number */ > int bond_major = 60; > /* Buffer to store data */ > char *bond_buffer; > > I am not sure if the above statement I wrote is supposed to be written like that only. > > static int bond_init(void) { > printk("<1> Hello bond new driver!\n"); > int result; > > > /* Registering device */ > result = register_chrdev(bond_major, "bond", &bond_fops); > if (result < 0) { > printk( > "<1>memory: cannot obtain major number %d\n", bond_major); > return result; > } > > > /* Allocating memory for the buffer */ > bond_buffer = kmalloc(1, GFP_KERNEL); > kmalloc here I passed on 10 (and compiled and checked there were same results no change) if any other changes let me know I will try. > if (!bond_buffer) { > result = -ENOMEM; > goto fail; > } > memset(bond_buffer, 0, 1); > > Changed the value of 1 to 10 here recompiled (did not worked same problem) Are you referring to this area to be changed. > printk("<1>Inserting bond module\n"); > return 0; > > > fail: > bond_exit(); > return result; > return 0; > } > > > static void bond_exit(void) { > printk("<1> Bye, bond world\n"); > /* Freeing the major number */ > unregister_chrdev(bond_major, "bond"); > > > /* Freeing buffer memory */ > if (bond_buffer) { > kfree(bond_buffer); > } > > > printk("<1>Removing bond module\n"); > > > > > } > > > module_init(bond_init); > module_exit(bond_exit); > > > I am not having any clue to any of above so let me know what you or some one reading this thread thinks about it.