On Wed, Oct 19, 2005 at 00:17:44 -0700, santosh pattar wrote:
> Hi,
>
> I am getting a problem when reading a file in kernel space. can any one help me with this.
Don't do it. Read the file in user-space and feed it in kernel via
device, procfs entry or netlink.
> #include <linux/module.h>
> #include <linux/fs.h>
> #include <linux/file.h>
> #include <linux/syscalls.h>
> MODULE_LICENSE("GPL");
> static char buff[100];
> int init_module(void)
> {
> struct file *filp;
> int unused_fd, nbr;
> printk("loading hello\n");
> filp = filp_open("a.txt",O_RDWR,0); // a.txt is a file which i need to read
> unused_fd = get_unused_fd();
Don't mess with file descriptors in kernel. Use the struct file *
directly.
> printk("unused_fd = %d\n", unused_fd);
> fd_install(unused_fd, filp);
> nbr = sys_read(unused_fd, buff, 100); // problem is here. nbr returning error.
*WHICH* error?
Learn about kernel and user-space memory and copy_to_user/copy_from_user
means and come back when you understand it.
> printk("nbr= %d", nbr);
> printk( "%s", buff);
> return 0;
> }
> void cleanup_module(void)
> {
> printk("Unloading hello\n");
> }
--
Jan 'Bulb' Hudec <bulb@xxxxxx>
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