On Sun, Apr 3, 2011 at 6:11 PM, Sengottuvelan S <sengottuvelan.s@gmail.com> wrote:
Hi All,
I am trying to access /dev/mem in my user process. I could not access because not a privileged access. I tried to use iopl(3) call in linux 2.6,
I am not sure, but after reading the manpage, it looks like iopl will give access to the IO ports not the files.
but i am getting unresolved symbol for this. Is any other way to get access in user process. I am not sure how to solve this. Can you someone throw some light on this.
if(iopl(3)){ fprintf(stderr, "Cannot get I/O permissions (being root helps)"); return -1; } if ((fd = open("/dev/mem", O_RDWR | O_SYNC)) < 0) { fprintf(stderr, "Failed to open /dev/mem"); return -1; }
If you look at the file permission, you will notice only root has permission to write the /dev/mem $ ls -l /dev/mem crw-r----- 1 root kmem 1, 1 2011-04-03 08:42 /dev/mem Opening it for read/write will surely fail. Thanks and Regards, Prasad
-- Regards, S. Sengottuvelan.
-- Regards, S. Sengottuvelan.
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies