Why I am getting this output when run readelf -s

Question

I have Linux Kernel with me and trying to generate ELF Header on it using objcopy tool, Below is the first step

     objcopy -I binary -B i386 -O elf32-i386 --rename-section .data=.text linux_kernel.bin  main.o

And after this I wanted to read symbol table using readelf -s main.o ,but getting strange symbols, below is output

   Symbol table '.symtab' contains 5 entries:
   Num:    Value  Size Type    Bind   Vis      Ndx Name
 0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND 
 1: 00000000     0 SECTION LOCAL  DEFAULT    1 
 2: 00000000     0 NOTYPE  GLOBAL DEFAULT    1 _binary_linux_kernel_bin_
 3: 004df650     0 NOTYPE  GLOBAL DEFAULT    1 _binary_linux_kernel_bin_
 4: 004df650     0 NOTYPE  GLOBAL DEFAULT  ABS _binary_linux_kernel_bin_

Now should be able to see symbols like

_binary_linux_kernel_bin_start
_binary_linux_kernel_bin__end
_binary_linux_kernel_bin_size

Can any body let me know where I am doing wrong?? or is it expected one??

Why I wanted to see proper symbol because have to do something like below one

 --entry_point=_binary_linux_kernel_bin_start

Answer 1

It is simply that the string is too long and readelf is truncating. Try objdump -x main.o.

Answer 2

You can use the readelf -W -s main.o command, where the -W tells readelf not to truncate the output to 80-character width.