Ask help for the value of _GLOBAL_OFFSET_TABLE_

[JL <abcd dot bpmf at gmail dot com>]

Hi,

I read the function elf_machine_dynamic() in sysdeps/i386/dl-machine.h
. so I want to use this function  in my prograom to get the
information of _GLOBAL_OFFSET_TABLE_ .

first, I want to get the value of symbol  _DYNAMIC .the program as below

=======================
/*test.c*/
#include <elf.h>
#include <stdio.h>

static inline Elf32_Addr __attribute__ ((unused, const))
        elf_machine_dynamic (void)
{
          extern const Elf32_Addr _GLOBAL_OFFSET_TABLE_[]
__attribute__ ((visibility ("hidden")));
            return _GLOBAL_OFFSET_TABLE_[0];
}

int main()
{
        printf ("0x%x\n", elf_machine_dynamic());
}

=======================
I use gcc compile it , when I run it , Segmentation fault (core dumped).

second, I want to get the value of _GLOBAL_OFFSET_TABLE, so  I modify
the statement "return _GLOBAL_OFFSET_TABLE_[0];" to "return
_GLOBAL_OFFSET_TABLE_;" in the function elf_machine_dynamic .

=======================
#include <elf.h>
#include <stdio.h>

static inline Elf32_Addr __attribute__ ((unused, const))
        elf_machine_dynamic (void)
{
          extern const Elf32_Addr _GLOBAL_OFFSET_TABLE_[]
__attribute__ ((visibility ("hidden")));
            return _GLOBAL_OFFSET_TABLE_;
}

int main()
{
        printf ("0x%x\n", elf_machine_dynamic());
}

======================= 
[tmp]$ gcc test.c
test.c: In function `elf_machine_dynamic':
test.c:8: warning: return makes integer from pointer without a cast
[tmp]$ ./a.out
0x11d3

but 
[tmp]$ readelf  -s a.out | grep _GLOBAL
    63: 08049578     0 OBJECT  GLOBAL DEFAULT   21 _GLOBAL_OFFSET_TABLE_

the value of _GLOBAL_OFFSET_TABLE_ is 08049578!

who can tell me where I made a mistake? thanks in advance.

David
1.19