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标题: Linux中ELF格式文件介绍（3） [打印本页]

作者: yuyang911220 时间: 2017-6-15 17:09 标题: Linux中ELF格式文件介绍（3）

这里，通过使用一些用于操作ELF文件的工具的例子，来对其有一个直观的了解。
1 readelf工具
readelf用来显示ELF格式目标文件的信息.可通过参数选项来控制显示哪些特定信息。
*读取elf文件头信息：
$ readelf -h fbtest
输入之后，输出如下：
ELF Header:
Magic: 7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
Class:                            ELF32
Data:                            2's complement, little endian
Version:                         1 (current)
OS/ABI:                         UNIX - System V
ABI Version:                      0
Type:                            EXEC (Executable file)
Machine:                         Intel 80386
Version:                         0x1
Entry point address:             0x80484d0
Start of program headers:       52 (bytes into file)
Start of section headers:       5924 (bytes into file)
Flags:                            0x0
Size of this header:             52 (bytes)
Size of program headers:          32 (bytes)
Number of program headers:       8
Size of section headers:          40 (bytes)
Number of section headers:       36
Section header string table index: 33
这里，fbtest是在本地使用gcc编译生成的一个简单的可执行程序。
*查看elf文件程序头表信息：
$readelf -l fbtest
输入之后，输出如下：
Program Headers:
Type          Offset VirtAddr PhysAddr FileSiz MemSiz  Flg Align
PHDR          0x000034 0x08048034 0x08048034 0x00100 0x00100 R E 0x4
INTERP       0x000134 0x08048134 0x08048134 0x00013 0x00013 R 0x1
[Requesting program interpreter: /lib/ld-linux.so.2]
LOAD          0x000000 0x08048000 0x08048000 0x00df4 0x00df4 R E 0x1000
LOAD          0x000f0c 0x08049f0c 0x08049f0c 0x00128 0x00178 RW  0x1000
DYNAMIC       0x000f20 0x08049f20 0x08049f20 0x000d0 0x000d0 RW  0x4
NOTE          0x000148 0x08048148 0x08048148 0x00020 0x00020 R 0x4
GNU_STACK    0x000000 0x00000000 0x00000000 0x00000 0x00000 RW  0x4
GNU_RELRO    0x000f0c 0x08049f0c 0x08049f0c 0x000f4 0x000f4 R 0x1
Section to Segment mapping:
Segment Sections...
00
01    .interp
02    .interp .note.ABI-tag .hash .gnu.hash .dynsym .dynstr .gnu.version .gnu.version_r .rel.dyn .rel.plt .init .plt .text .fini .rodata .eh_frame
03    .ctors .dtors .jcr .dynamic .got .got.plt .data .bss
04    .dynamic
05    .note.ABI-tag
06
07    .ctors .dtors .jcr .dynamic .got
*查看elf文件的节信息：
$readelf -S libmy.so
输入之后，输出如下：
There are 33 section headers, starting at offset 0xfd0:
Section Headers:
[Nr] Name             Type          Addr    Off Size ES Flg Lk Inf Al
[ 0]                NULL          00000000 000000 000000 00    0 0  0
[ 1] .hash          HASH          000000d4 0000d4 0000a0 04 A  3 0  4
[ 2] .gnu.hash       GNU_HASH       00000174 000174 000040 04 A  3 0  4
[ 3] .dynsym          DYNSYM       000001b4 0001b4 000150 10 A  4 1  4
[ 4] .dynstr          STRTAB       00000304 000304 00018a 00 A  0 0  1
[ 5] .gnu.version    VERSYM       0000048e 00048e 00002a 02 A  3 0  2
[ 6] .gnu.version_r VERNEED       000004b8 0004b8 000020 00 A  4 1  4
[ 7] .rel.dyn       REL          000004d8 0004d8 0000e8 08 A  3 0  4
[ 8] .rel.plt       REL          000005c0 0005c0 000010 08 A  3  10  4
[ 9] .init          PROGBITS       000005d0 0005d0 000030 00  AX  0 0  4
[10] .plt             PROGBITS       00000600 000600 000030 04  AX  0 0  4
[11] .text          PROGBITS       00000630 000630 0002a4 00  AX  0 0 16
[12] .fini          PROGBITS       000008d4 0008d4 00001c 00  AX  0 0  4
[13] .rodata          PROGBITS       000008f0 0008f0 000006 00 A  0 0  1
[14] .eh_frame_hdr    PROGBITS       000008f8 0008f8 000034 00 A  0 0  4
[15] .eh_frame       PROGBITS       0000092c 00092c 0000d8 00 A  0 0  4
[16] .ctors          PROGBITS       00001a04 000a04 00000c 00  WA  0 0  4
[17] .dtors          PROGBITS       00001a10 000a10 000008 00  WA  0 0  4
[18] .jcr             PROGBITS       00001a18 000a18 000004 00  WA  0 0  4
[19] .dynamic       DYNAMIC       00001a1c 000a1c 0000d0 08  WA  4 0  4
[20] .got             PROGBITS       00001aec 000aec 00000c 04  WA  0 0  4
[21] .got.plt       PROGBITS       00001af8 000af8 000014 04  WA  0 0  4
[22] .data          PROGBITS       00001b0c 000b0c 000008 00  WA  0 0  4
[23] .bss             NOBITS       00001b14 000b14 000008 00  WA  0 0  4
[24] .comment       PROGBITS       00000000 000b14 0000d2 00    0 0  1
[25] .debug_aranges PROGBITS       00000000 000be8 000050 00    0 0  8
[26] .debug_info    PROGBITS       00000000 000c38 00011a 00    0 0  1
[27] .debug_abbrev    PROGBITS       00000000 000d52 000024 00    0 0  1
[28] .debug_line    PROGBITS       00000000 000d76 000102 00    0 0  1
[29] .debug_ranges    PROGBITS       00000000 000e78 000040 00    0 0  8
[30] .shstrtab       STRTAB       00000000 000eb8 000116 00    0 0  1
[31] .symtab          SYMTAB       00000000 0014f8 0004c0 10    32  56  4
[32] .strtab          STRTAB       00000000 0019b8 00031c 00    0 0  1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings)
I (info), L (link order), G (group), x (unknown)
O (extra OS processing required) o (OS specific), p (processor specific)
这里的libmy.so是自行生成的一个共享库。

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