access pointer and global variables

[Stone, Joshua I]

Wenji Huang wrote:
>    c. char *
>        probe kernel.function("sys_open") {
>           //parameter list in source:   const char __user *filename, int 
> flags, int mode) 
>           $filename can be accessed, but how to get the string of 
> filename point ?
>        }

I'm not sure about your other questions, but I'll answer the easy one. 
To read a string from a pointer, use either kernel_string() or 
user_string().  Since $filename is a __user pointer, you should use the 
latter.

Alternately, you can use the tapset alias "syscall.open" which gives you 
variables that are already dereferenced.


Josh