Writing to a specific virtural address???

[Tony31]

Hello all,

Question: Is there a way to write to a specific virtural address space (or even better, a specific physical address space).

I am running Solaris 9 (which I know they won't let me write to physical address space directly - because I can only execute program in USER space). So my best best is to write a known value to a known virtural address space.

If you are wondering why, it is because I am writing a memory checker. I have the physical page I want locked. Now, I am just not sure how to write to it directly.

-Tony

[Quantum1024]

Something like this

int *ptr=(int *)0x00; //point to address 0x00
*ptr=1;//set it to 1

Of course that example will crash.

[jim mcnamara]

If you want to read/write memory that is not part of your process you have to be in kernel mode. Debuggers do this routinely.

/usr/proc/bin/pmap -x <pid>

will show the physical addresses a process has on Solaris

I don't know enough Solaris to really help, but the source for the GNU debugger
is here:

http://www.gnu.org/software/gdb/gdb.html

If your version of Solaris supports the ptrace library <sys/ptrace.h>
then you have a leg up.

[Salem]

> I have the physical page I want locked.
My guess is whatever routine you called to get that returned an equivalent virtual address.

Say
unsigned char *myVirtualAddress = someOsPageLockingFunction( myPhysicalPage );

myVirtualAddress[0] is therefore the first location of that page.

Or if you feel like exercising your root powers, try looking at /dev/mem or something.