Hi All: I am trying to develop a simple encrypted stackable file system. Instead of making a new stackable file system I modified nullfs code itself. I added null_read() and null_write() functions. null_read() internally calls VOP_READ() and null_write() calls VOP_WRITE() (it bypass control to lower vnode vectors VOPS). The code of null_write() function is such that before calling VOP_WRITE() it increments each character pointed by uio_iov->iov_base[i] by 1 and null_read() does the opposite ie it decrement each character pointed by uio_iov->iov_base[i] by 1 after calling VOP_READ. So for example if I open a file and store "ABCDE" it actually gets stored as "BCDEF" but when I read it back using cat program or read system call I get "BCDEF" not "ABCDE".I can see the code is going to null_read() and uio_iov->iov_base[i] is actually printing "ABCDE" on console. Whats surprising is that user space cat or read system call are not giving the correct output or I should say that modified uio structure is not reflected in user space.
I am mounting using this command sudo mount -t null /mnt/ /TMP/ So in /TMP dir has a nullfs is on top of ufs Am I missing something here ? I can see that the control is actually going to null_read and null_write and I have tested that nullfs is on top of ufs in /TMP directory. thank you Somil To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message
