Memory maps

Memory maps

[Fu-hau Hsu]

Dear freinds:

 I have following questions about memory maps. I appreciate any
suggestion.

 Q. (1)When a process is running, how can I get the range of data, stack,
       and code segments, say the stack segment is from address 0x..... to
       0x..... so do data segments and code segments?
       PS: Under ELF format, there are several seperaed code and data
           segments, but the process control table has only one pair of
           pointers for each, Are the pointers still useful?
    
    (2) /proc/*/maps will show us those info, but how does it get these
       info? 


FuHau 

Re: Memory maps

[Eric W. Biederman]

Fu-hau Hsu <fhsu@ic.sunysb.edu> writes:

> Dear freinds:
> 
>  I have following questions about memory maps. I appreciate any
> suggestion.
> 
>  Q. (1)When a process is running, how can I get the range of data, stack,
>        and code segments, say the stack segment is from address 0x..... to
>        0x..... so do data segments and code segments?
>        PS: Under ELF format, there are several seperaed code and data
>            segments, but the process control table has only one pair of
>            pointers for each, Are the pointers still useful?


Sort of, you can currently confuse the elf loader with multiple bss segments.
The stack, and the brk pointer are still used. 

>     (2) /proc/*/maps will show us those info, but how does it get these
>        info? 

This is a reflection of what areas of memory the kernel sees.  In principle
every thing is now handled by mmap, and this /proc/maps is a reflection
of that.  See under the files in mm/*.c

Eric