I am doing a "cp" in kernel space. That is, making a copy of a file (after manipulating it a bit) in kernel code. I know it is bad design but the purpose of the code is to learn so I don't really mind doing it. 1. I am using the filp_open in kernel space (with O_CREAT|O_WRONLY). 2. My source file is say a struct file *sourcefp; 3. I want my destination file (say struct file *destfp) to have the same rwx permissions as the source file. using sourcefp->f_dentry->d_inode->i_mode as the mode (third parameter in the filp_open) works fine. Can someone point out the difference between the i_mode in struct inode and the f_mode in the struct file. Also is it safe to use i_mode directly (without any macros)? Do any macros exist for doing this? Another question I have is that is are there any security issues if I use the following code blindly? fs = get_fs(); set_fs(get_ds()); /* code here */ set_fs(fs); I understand that the code above makes sure that kernel space pointers do not fail in the verify_area function. Is it wrong (from a design point of view) to use functions in the kernel space that expect user space pointers? For the cp in kernel space part , I ended up using the read function pointer of the struct file* -> file_operations. Just wanted to know that if I ever end up writing code that requires the get_fs/ set_fs as above, then should I rethink the design? BTW - The kernel level cp is only for learning purposes and not a part of any design as such. Thanks in advance. -mohit Regards, Mohit Kalra "It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts." -SH -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
