Objdump command in Linux is used to provide thorough information on object files. This command is mainly used by the programmers who work on compilers, but still its a very handy tool for normal programmers also when it comes to debugging. In this article, we will understand how to use objdump command through some examples.
Basic syntax of objdump is :
objdump [options] objfile...
There is a wide range of options available for this command. We will try to cover a good amount of them in this tutorial.
Examples
The ELF binary file of the following C program is used in all the examples mentioned in this article.
#include<stdio.h>
int main(void)
{
int n = 6;
float f=1;
int i = 1;
for(;i<=n;i++)
f=f*i;
printf("\n Factorial is : [%f]\n",f);
return 0;
}
Note: The above is just a test code that was being used for some other purpose, but I found it simple enough to use for this article.
1. Display the contents of the overall file header using -f option
Consider the following example :
$ objdump -f factorial factorial: file format elf64-x86-64 architecture: i386:x86-64, flags 0x00000112: EXEC_P, HAS_SYMS, D_PAGED start address 0x0000000000400440
So we see that the information related to the overall file header was shown in the output.
NOTE: The executable format used in the examples is ELF. To know more about it, refer to our article on ELF file format.
2.Display object format specific file header contents using -p option
The following example prints the object file format specific information.
$ objdump -p factorial
factorial: file format elf64-x86-64
Program Header:
PHDR off 0x0000000000000040 vaddr 0x0000000000400040 paddr 0x0000000000400040 align 2**3
filesz 0x00000000000001f8 memsz 0x00000000000001f8 flags r-x
INTERP off 0x0000000000000238 vaddr 0x0000000000400238 paddr 0x0000000000400238 align 2**0
filesz 0x000000000000001c memsz 0x000000000000001c flags r--
LOAD off 0x0000000000000000 vaddr 0x0000000000400000 paddr 0x0000000000400000 align 2**21
filesz 0x0000000000000734 memsz 0x0000000000000734 flags r-x
LOAD off 0x0000000000000e18 vaddr 0x0000000000600e18 paddr 0x0000000000600e18 align 2**21
filesz 0x0000000000000208 memsz 0x0000000000000218 flags rw-
DYNAMIC off 0x0000000000000e40 vaddr 0x0000000000600e40 paddr 0x0000000000600e40 align 2**3
filesz 0x00000000000001a0 memsz 0x00000000000001a0 flags rw-
..
Dynamic Section:
NEEDED libc.so.6
INIT 0x00000000004003f0
FINI 0x0000000000400668
HASH 0x0000000000400298
GNU_HASH 0x00000000004002c0
STRTAB 0x0000000000400340
SYMTAB 0x00000000004002e0
STRSZ 0x000000000000003f
SYMENT 0x0000000000000018
DEBUG 0x0000000000000000
PLTGOT 0x0000000000600fe8
..
Version References:
required from libc.so.6:
0x09691a75 0x00 02 GLIBC_2.2.5
3. Display the contents of the section headers using -h option
There can be various sections in an object file. Information related to them can be printed using -h option.
The following examples shows various sections. As you see there are total of 26 (only partial output is shown here).
$ objdump -h factorial
factorial: file format elf64-x86-64
Sections:
Idx Name Size VMA LMA File off Algn
0 .interp 0000001c 0000000000400238 0000000000400238 00000238 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
1 .note.ABI-tag 00000020 0000000000400254 0000000000400254 00000254 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
2 .note.gnu.build-id 00000024 0000000000400274 0000000000400274 00000274 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
3 .hash 00000024 0000000000400298 0000000000400298 00000298 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
....
14 .fini 0000000e 0000000000400668 0000000000400668 00000668 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
15 .rodata 0000001b 0000000000400678 0000000000400678 00000678 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
16 .eh_frame_hdr 00000024 0000000000400694 0000000000400694 00000694 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
17 .eh_frame 0000007c 00000000004006b8 00000000004006b8 000006b8 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
18 .ctors 00000010 0000000000600e18 0000000000600e18 00000e18 2**3
CONTENTS, ALLOC, LOAD, DATA
19 .dtors 00000010 0000000000600e28 0000000000600e28 00000e28 2**3
CONTENTS, ALLOC, LOAD, DATA
...
23 .got.plt 00000028 0000000000600fe8 0000000000600fe8 00000fe8 2**3
CONTENTS, ALLOC, LOAD, DATA
24 .data 00000010 0000000000601010 0000000000601010 00001010 2**3
CONTENTS, ALLOC, LOAD, DATA
25 .bss 00000010 0000000000601020 0000000000601020 00001020 2**3
ALLOC
26 .comment 00000023 0000000000000000 0000000000000000 00001020 2**0
CONTENTS, READONLY
So we see that the information related to all the section headers was printed in the output. In the output above, Size is the size of the loaded section, VMA represents the virtual memory address, LMA represents the logical memory address, File off is this section’s offset from the beginning of the file, Algn represents alignment, CONTENTS, ALLOC, LOAD, READONLY, DATA are flags that represent that a particular section is to be LOADED or is READONLY etc.
4. Display the contents of all headers using -x option
Information related to all the headers in the object file can be retrieved using the -x option.
The following example displays all the sections (only partial output is shown here):
$ objdump -x factorial
factorial: file format elf64-x86-64
factorial
architecture: i386:x86-64, flags 0x00000112:
EXEC_P, HAS_SYMS, D_PAGED
start address 0x0000000000400440
Program Header:
PHDR off 0x0000000000000040 vaddr 0x0000000000400040 paddr 0x0000000000400040 align 2**3
filesz 0x00000000000001f8 memsz 0x00000000000001f8 flags r-x
INTERP off 0x0000000000000238 vaddr 0x0000000000400238 paddr 0x0000000000400238 align 2**0
filesz 0x000000000000001c memsz 0x000000000000001c flags r--
.....
EH_FRAME off 0x0000000000000694 vaddr 0x0000000000400694 paddr 0x0000000000400694 align 2**2
filesz 0x0000000000000024 memsz 0x0000000000000024 flags r--
STACK off 0x0000000000000000 vaddr 0x0000000000000000 paddr 0x0000000000000000 align 2**3
filesz 0x0000000000000000 memsz 0x0000000000000000 flags rw-
RELRO off 0x0000000000000e18 vaddr 0x0000000000600e18 paddr 0x0000000000600e18 align 2**0
filesz 0x00000000000001e8 memsz 0x00000000000001e8 flags r--
Dynamic Section:
NEEDED libc.so.6
INIT 0x00000000004003f0
FINI 0x0000000000400668
HASH 0x0000000000400298
GNU_HASH 0x00000000004002c0
STRTAB 0x0000000000400340
SYMTAB 0x00000000004002e0
STRSZ 0x000000000000003f
....
Version References:
required from libc.so.6:
0x09691a75 0x00 02 GLIBC_2.2.5
Sections:
Idx Name Size VMA LMA File off Algn
0 .interp 0000001c 0000000000400238 0000000000400238 00000238 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
1 .note.ABI-tag 00000020 0000000000400254 0000000000400254 00000254 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
2 .note.gnu.build-id 00000024 0000000000400274 0000000000400274 00000274 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
3 .hash 00000024 0000000000400298 0000000000400298 00000298 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
4 .gnu.hash 0000001c 00000000004002c0 00000000004002c0 000002c0 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
.....
18 .ctors 00000010 0000000000600e18 0000000000600e18 00000e18 2**3
CONTENTS, ALLOC, LOAD, DATA
19 .dtors 00000010 0000000000600e28 0000000000600e28 00000e28 2**3
CONTENTS, ALLOC, LOAD, DATA
20 .jcr 00000008 0000000000600e38 0000000000600e38 00000e38 2**3
CONTENTS, ALLOC, LOAD, DATA
21 .dynamic 000001a0 0000000000600e40 0000000000600e40 00000e40 2**3
CONTENTS, ALLOC, LOAD, DATA
22 .got 00000008 0000000000600fe0 0000000000600fe0 00000fe0 2**3
CONTENTS, ALLOC, LOAD, DATA
23 .got.plt 00000028 0000000000600fe8 0000000000600fe8 00000fe8 2**3
CONTENTS, ALLOC, LOAD, DATA
24 .data 00000010 0000000000601010 0000000000601010 00001010 2**3
CONTENTS, ALLOC, LOAD, DATA
25 .bss 00000010 0000000000601020 0000000000601020 00001020 2**3
ALLOC
26 .comment 00000023 0000000000000000 0000000000000000 00001020 2**0
CONTENTS, READONLY
SYMBOL TABLE:
0000000000400238 l d .interp 0000000000000000 .interp
0000000000400254 l d .note.ABI-tag 0000000000000000 .note.ABI-tag
0000000000400274 l d .note.gnu.build-id 0000000000000000 .note.gnu.build-id
0000000000400298 l d .hash 0000000000000000 .hash
00000000004002c0 l d .gnu.hash 0000000000000000 .gnu.hash
00000000004002e0 l d .dynsym 0000000000000000 .dynsym
0000000000400340 l d .dynstr 0000000000000000 .dynstr
0000000000400380 l d .gnu.version 0000000000000000 .gnu.version
0000000000400388 l d .gnu.version_r 0000000000000000 .gnu.version_r
....
0000000000600e30 g O .dtors 0000000000000000 .hidden __DTOR_END__
00000000004005a0 g F .text 0000000000000089 __libc_csu_init
0000000000601020 g *ABS* 0000000000000000 __bss_start
0000000000601030 g *ABS* 0000000000000000 _end
0000000000601020 g *ABS* 0000000000000000 _edata
0000000000400524 g F .text 0000000000000060 main
00000000004003f0 g F .init 0000000000000000 _init
5. Display assembler contents of executable sections using -d option
Consider the following example. The assembler contents of executable sections (in the object file) are displayed in this output (partial output shown below):
$ objdump -d factorial factorial: file format elf64-x86-64 Disassembly of section .init: 00000000004003f0 : 4003f0: 48 83 ec 08 sub $0x8,%rsp 4003f4: e8 73 00 00 00 callq 40046c .. Disassembly of section .plt: 0000000000400408 : 400408: ff 35 e2 0b 20 00 pushq 0x200be2(%rip) # 600ff0 40040e: ff 25 e4 0b 20 00 jmpq *0x200be4(%rip) # 600ff8 400414: 0f 1f 40 00 nopl 0x0(%rax) 0000000000400418 : 400418: ff 25 e2 0b 20 00 jmpq *0x200be2(%rip) # 601000 40041e: 68 00 00 00 00 pushq $0x0 400423: e9 e0 ff ff ff jmpq 400408 0000000000400428 : 400428: ff 25 da 0b 20 00 jmpq *0x200bda(%rip) # 601008 40042e: 68 01 00 00 00 pushq $0x1 400433: e9 d0 ff ff ff jmpq 400408 Disassembly of section .text: 0000000000400440 : 400440: 31 ed xor %ebp,%ebp 400442: 49 89 d1 mov %rdx,%r9 400445: 5e pop %rsi ... 000000000040046c : 40046c: 48 83 ec 08 sub $0x8,%rsp 400470: 48 8b 05 69 0b 20 00 mov 0x200b69(%rip),%rax # 600fe0 400477: 48 85 c0 test %rax,%rax 40047a: 74 02 je 40047e 40047c: ff d0 callq *%rax ... 0000000000400490 : 400490: 55 push %rbp 400491: 48 89 e5 mov %rsp,%rbp 400494: 53 push %rbx 400495: 48 83 ec 08 sub $0x8,%rsp 400499: 80 3d 80 0b 20 00 00 cmpb $0x0,0x200b80(%rip) # 601020 4004a0: 75 4b jne 4004ed 4004a2: bb 30 0e 60 00 mov $0x600e30,%ebx 4004fb: 00 00 00 00 00 ... 0000000000400500 : 400500: 55 push %rbp 400501: 48 83 3d 2f 09 20 00 cmpq $0x0,0x20092f(%rip) # 600e38 400508: 00 400509: 48 89 e5 mov %rsp,%rbp 40050c: 74 12 je 400520 40050e: b8 00 00 00 00 mov $0x0,%eax 400513: 48 85 c0 test %rax,%rax 400516: 74 08 je 400520 400518: bf 38 0e 60 00 mov $0x600e38,%edi 40051d: c9 leaveq 40051e: ff e0 jmpq *%rax 400520: c9 leaveq 400521: c3 retq 400522: 90 nop 400523: 90 nop 0000000000400524 : 400524: 55 push %rbp 400525: 48 89 e5 mov %rsp,%rbp 400528: 48 83 ec 10 sub $0x10,%rsp 40052c: c7 45 fc 06 00 00 00 movl $0x6,-0x4(%rbp) 400533: b8 00 00 80 3f mov $0x3f800000,%eax 400538: 89 45 f8 mov %eax,-0x8(%rbp) ... Disassembly of section .fini: 0000000000400668 : 400668: 48 83 ec 08 sub $0x8,%rsp 40066c: e8 1f fe ff ff callq 400490 400671: 48 83 c4 08 add $0x8,%rsp 400675: c3 retq
6. Display assembler contents of all sections using -D option
In case the assembler contents of all the sections is required in output, the option -D can be used.
Consider the following output :
$ objdump -D factorial | pager
factorial: file format elf64-x86-64
Disassembly of section .interp:
0000000000400238 :
400238: 2f (bad)
400239: 6c insb (%dx),%es:(%rdi)
40023a: 69 62 36 34 2f 6c 64 imul $0x646c2f34,0x36(%rdx),%esp
400241: 2d 6c 69 6e 75 sub $0x756e696c,%eax
400246: 78 2d js 400275
400248: 78 38 js 400282
40024a: 36 ss
40024b: 2d 36 34 2e 73 sub $0x732e3436,%eax
400250: 6f outsl %ds:(%rsi),(%dx)
400251: 2e 32 00 xor %cs:(%rax),%al
Disassembly of section .note.ABI-tag:
0000000000400254 :
400254: 04 00 add $0x0,%al
400256: 00 00 add %al,(%rax)
400258: 10 00 adc %al,(%rax)
40025a: 00 00 add %al,(%rax)
40025c: 01 00 add %eax,(%rax)
40025e: 00 00 add %al,(%rax)
400260: 47 rex.RXB
400261: 4e 55 rex.WRX push %rbp
400263: 00 00 add %al,(%rax)
400265: 00 00 add %al,(%rax)
400267: 00 02 add %al,(%rdx)
400269: 00 00 add %al,(%rax)
40026b: 00 06 add %al,(%rsi)
40026d: 00 00 add %al,(%rax)
40026f: 00 0f add %cl,(%rdi)
400271: 00 00 add %al,(%rax)
...
...
...
So we see that the relevant output was displayed. Since the output was very long, so I clipped it. Note that I used the pager command for controlling the output.
7. Display the full contents of all sections using -s option
Consider the following example :
$ objdump -s factorial factorial: file format elf64-x86-64 Contents of section .interp: 400238 2f6c6962 36342f6c 642d6c69 6e75782d /lib64/ld-linux- 400248 7838362d 36342e73 6f2e3200 x86-64.so.2. Contents of section .note.ABI-tag: 400254 04000000 10000000 01000000 474e5500 ............GNU. 400264 00000000 02000000 06000000 0f000000 ................ Contents of section .note.gnu.build-id: 400274 04000000 14000000 03000000 474e5500 ............GNU. 400284 c6928568 6751d6de 6ddd2eb1 7c5cd0ff ...hgQ..m...|\.. 400294 670751c6 g.Q. Contents of section .hash: 400298 03000000 04000000 02000000 03000000 ................ 4002a8 01000000 00000000 00000000 00000000 ................ 4002b8 00000000 .... Contents of section .gnu.hash: 4002c0 01000000 01000000 01000000 00000000 ................ 4002d0 00000000 00000000 00000000 ............ Contents of section .dynsym: 4002e0 00000000 00000000 00000000 00000000 ................ 4002f0 00000000 00000000 1a000000 12000000 ................ 400300 00000000 00000000 00000000 00000000 ................ 400310 01000000 20000000 00000000 00000000 .... ........... 400320 00000000 00000000 21000000 12000000 ........!....... 400330 00000000 00000000 00000000 00000000 ................ Contents of section .dynstr: 400340 005f5f67 6d6f6e5f 73746172 745f5f00 .__gmon_start__. 400350 6c696263 2e736f2e 36007072 696e7466 libc.so.6.printf 400360 005f5f6c 6962635f 73746172 745f6d61 .__libc_start_ma 400370 696e0047 4c494243 5f322e32 2e3500 in.GLIBC_2.2.5. Contents of section .gnu.version: 400380 00000200 00000200 ........ Contents of section .gnu.version_r: 400388 01000100 10000000 10000000 00000000 ................ 400398 751a6909 00000200 33000000 00000000 u.i.....3....... Contents of section .rela.dyn: 4003a8 e00f6000 00000000 06000000 02000000 ..`............. 4003b8 00000000 00000000 ........ Contents of section .rela.plt: 4003c0 00106000 00000000 07000000 01000000 ..`............. 4003d0 00000000 00000000 08106000 00000000 ..........`..... 4003e0 07000000 03000000 00000000 00000000 ................ Contents of section .init: 4003f0 4883ec08 e8730000 00e80201 0000e82d H....s.........- 400400 02000048 83c408c3 ...H.... Contents of section .plt: 400408 ff35e20b 2000ff25 e40b2000 0f1f4000 .5.. ..%.. ...@. 400418 ff25e20b 20006800 000000e9 e0ffffff .%.. .h......... 400428 ff25da0b 20006801 000000e9 d0ffffff .%.. .h......... Contents of section .text: 400440 31ed4989 d15e4889 e24883e4 f0505449 1.I..^H..H...PTI 400450 c7c09005 400048c7 c1a00540 0048c7c7 ....@.H....@.H.. 400460 24054000 e8bfffff fff49090 4883ec08 $.@.........H... 400470 488b0569 0b200048 85c07402 ffd04883 H..i. .H..t...H. 400480 c408c390 90909090 90909090 90909090 ................ 400490 554889e5 534883ec 08803d80 0b200000 UH..SH....=.. .. .... 4005e0 e80bfeff ff4885ed 741c31db 0f1f4000 .....H..t.1...@. 4005f0 4c89fa4c 89f64489 ef41ff14 dc4883c3 L..L..D..A...H.. 400600 014839eb 72ea488b 5c240848 8b6c2410 .H9.r.H.\$.H.l$. 400610 4c8b6424 184c8b6c 24204c8b 7424284c L.d$.L.l$ L.t$(L 400620 8b7c2430 4883c438 c3909090 90909090 .|$0H..8........ 400630 554889e5 534883ec 08488b05 d8072000 UH..SH...H.... . 400640 4883f8ff 7419bb18 0e60000f 1f440000 H...t....`...D.. 400650 4883eb08 ffd0488b 034883f8 ff75f148 H.....H..H...u.H 400660 83c4085b c9c39090 ...[.... Contents of section .fini: 400668 4883ec08 e81ffeff ff4883c4 08c3 H........H.... Contents of section .rodata: 400678 01000200 0a204661 63746f72 69616c20 ..... Factorial 400688 6973203a 205b2566 5d0a00 is : [%f].. Contents of section .eh_frame_hdr: 400694 011b033b 20000000 03000000 90feffff ...; ........... 4006a4 3c000000 fcfeffff 5c000000 0cffffff
So we see that the complete contents for all the sections were displayed in the output.
8. Display debug information using -g option
Consider the following example:
$ objdump -g factorial factorial: file format elf64-x86-64
So we see that all the available debug information was printed in output.
9. Display the contents of symbol table (or tables) using the -t option
Consider the following example :
$ objdump -t factorial factorial: file format elf64-x86-64 SYMBOL TABLE: 0000000000400238 l d .interp 0000000000000000 .interp 0000000000400254 l d .note.ABI-tag 0000000000000000 .note.ABI-tag 0000000000400274 l d .note.gnu.build-id 0000000000000000 .note.gnu.build-id 0000000000400298 l d .hash 0000000000000000 .hash 00000000004002c0 l d .gnu.hash 0000000000000000 .gnu.hash 00000000004002e0 l d .dynsym 0000000000000000 .dynsym 0000000000400340 l d .dynstr 0000000000000000 .dynstr 0000000000400380 l d .gnu.version 0000000000000000 .gnu.version ..... 0000000000601010 g .data 0000000000000000 __data_start 0000000000601018 g O .data 0000000000000000 .hidden __dso_handle 0000000000600e30 g O .dtors 0000000000000000 .hidden __DTOR_END__ 00000000004005a0 g F .text 0000000000000089 __libc_csu_init 0000000000601020 g *ABS* 0000000000000000 __bss_start 0000000000601030 g *ABS* 0000000000000000 _end 0000000000601020 g *ABS* 0000000000000000 _edata 0000000000400524 g F .text 0000000000000060 main 00000000004003f0 g F .init 0000000000000000 _init
So we see that the contents of symbol table were displayed in the output.
10. Display the contents of dynamic symbol table using -T option
Dynamic symbols are those which are resolved during run time. The information related to these symbols can be retrieved using the -D option.
Consider the following example :
$ objdump -T factorial factorial: file format elf64-x86-64 DYNAMIC SYMBOL TABLE: 0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 printf 0000000000000000 w D *UND* 0000000000000000 __gmon_start__ 0000000000000000 DF *UND* 0000000000000000 GLIBC_2.2.5 __libc_start_main
So we see that information related to dynamic symbols was displayed in output.
11. Display the dynamic relocation entries in the file using -R option
Consider the following example:
$ objdump -R factorial factorial: file format elf64-x86-64 DYNAMIC RELOCATION RECORDS OFFSET TYPE VALUE 0000000000600fe0 R_X86_64_GLOB_DAT __gmon_start__ 0000000000601000 R_X86_64_JUMP_SLOT printf 0000000000601008 R_X86_64_JUMP_SLOT __libc_start_main
So we see that all the dynamic relocation entries were displayed in the output.
12. Display section of interest using -j option
This is extremely useful when you know the section related to which the information is required. The option -j is used in this case.
Consider the following example :
$ objdump -s -j.rodata factorial factorial: file format elf64-x86-64 Contents of section .rodata: 400678 01000200 0a204661 63746f72 69616c20 ..... Factorial 400688 6973203a 205b2566 5d0a00 is : [%f]..
So we see that information related to rodata section was displayed above.
13. Use the older disassembly format using –prefix-addresses option
The older format prints the complete address on each line.
Consider the following example :
$ objdump -D --prefix-addresses factorial
factorial: file format elf64-x86-64
Disassembly of section .interp:
0000000000400238 <.interp> (bad)
0000000000400239 <.interp+0x1> insb (%dx),%es:(%rdi)
000000000040023a <.interp+0x2> imul $0x646c2f34,0x36(%rdx),%esp
0000000000400241 <.interp+0x9> sub $0x756e696c,%eax
0000000000400246 <.interp+0xe> js 0000000000400275 <_init-0x17b>
0000000000400248 <.interp+0x10> js 0000000000400282 <_init-0x16e>
000000000040024a <.interp+0x12> ss
000000000040024b <.interp+0x13> sub $0x732e3436,%eax
0000000000400250 <.interp+0x18> outsl %ds:(%rsi),(%dx)
0000000000400251 <.interp+0x19> xor %cs:(%rax),%al
Disassembly of section .note.ABI-tag:
0000000000400254 <.note.ABI-tag> add $0x0,%al
0000000000400256 <.note.ABI-tag+0x2> add %al,(%rax)
0000000000400258 <.note.ABI-tag+0x4> adc %al,(%rax)
000000000040025a <.note.ABI-tag+0x6> add %al,(%rax)
000000000040025c <.note.ABI-tag+0x8> add %eax,(%rax)
000000000040025e <.note.ABI-tag+0xa> add %al,(%rax)
0000000000400260 <.note.ABI-tag+0xc> rex.RXB
0000000000400261 <.note.ABI-tag+0xd> rex.WRX push %rbp
0000000000400263 <.note.ABI-tag+0xf> add %al,(%rax)
0000000000400265 <.note.ABI-tag+0x11> add %al,(%rax)
0000000000400267 <.note.ABI-tag+0x13> add %al,(%rdx)
0000000000400269 <.note.ABI-tag+0x15> add %al,(%rax)
000000000040026b <.note.ABI-tag+0x17> add %al,(%rsi)
000000000040026d <.note.ABI-tag+0x19> add %al,(%rax)
000000000040026f <.note.ABI-tag+0x1b> add %cl,(%rdi)
0000000000400271 <.note.ABI-tag+0x1d> add %al,(%rax)
...
Disassembly of section .note.gnu.build-id:
0000000000400274 <.note.gnu.build-id> add $0x0,%al
0000000000400276 <.note.gnu.build-id+0x2> add %al,(%rax)
0000000000400278 <.note.gnu.build-id+0x4> adc $0x0,%al
...
...
...
So we see that complete address were printed in the output.
14. Accept input options from a file using @ option
If you want, the options to objdump can be read from a file. This can be done using ‘@’ option.
Consider the following example :
$ objdump -v -i GNU objdump (GNU Binutils for Ubuntu) 2.20.1-system.20100303 Copyright 2009 Free Software Foundation, Inc. This program is free software; you may redistribute it under the terms of the GNU General Public License version 3 or (at your option) any later version. This program has absolutely no warranty.
In this example above, I have used the -v and -i options. While -v is used to print the version information, -i is used to provide supported object formats and architectures.
Now I created a file and add these two options there.
$ cat options.txt -v -i
Execute the objdump by calling the options.txt file as shown below. This displays the same output as above, as it is reading the options from the options.txt file.
$ objdump @options.txt GNU objdump (GNU Binutils for Ubuntu) 2.20.1-system.20100303 Copyright 2009 Free Software Foundation, Inc. This program is free software; you may redistribute it under the terms of the GNU General Public License version 3 or (at your option) any later version. This program has absolutely no warranty.
My name is Ramesh Natarajan. I will be posting instruction guides, how-to, troubleshooting tips and tricks on Linux, database, hardware, security and web. My focus is to write articles that will either teach you or help you resolve a problem. Read more about
Comments on this entry are closed.
Since now ELF is the format standard , isnt “readelf” a flexible command for program and section headers ? objdump is anyway best suited for disassemble object code .
you must clarify what connection between those adressess (logical or virtual) with the label,
like:
0 .interp 0000001c 0000000000400238 0000000000400238
how to read and associate between .interp and 0000000000400238..
i’m a newbie and i want to learn…^_^
Is there a way to find out which part of the instructions, i.e. which addresses, from assembler contents of executable sections are from each C code and which part of it is from linking dynamic libraries?
I meant static libraries!