|
#include <stdio.h>
int main()
{
?? ?return 0;
}
/* 确认入口地址 */
$ readelf -h 00
ELF Header:
? Magic:?? 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
? Class:???????????????????????????? ELF64
? Data:????????????????????????????? 2's complement, little endian
? Version:?????????????????????????? 1 (current)
? OS/ABI:??????????????????????????? UNIX - System V
? ABI Version:?????????????????????? 0
? Type:????????????????????????????? DYN (Shared object file)
? Machine:?????????????????????????? Advanced Micro Devices X86-64
? Version:?????????????????????????? 0x1
? Entry point address:?????????????? 0x1040
? Start of program headers:????????? 64 (bytes into file)
? Start of section headers:????????? 16800 (bytes into file)
? Flags:???????????????????????????? 0x0
? Size of this header:?????????????? 64 (bytes)
? Size of program headers:?????????? 56 (bytes)
? Number of program headers:???????? 13
? Size of section headers:?????????? 64 (bytes)
? Number of section headers:???????? 34
? Section header string table index: 33
/* 反汇编 */
0000000000001040 <_start>:
??? 1040:?? ?f3 0f 1e fa???????? ??? ?endbr64
??? 1044:?? ?31 ed?????????????? ??? ?xor??? %ebp,%ebp
??? 1046:?? ?49 89 d1??????????? ??? ?mov??? %rdx,%r9
??? 1049:?? ?5e????????????????? ??? ?pop??? %rsi
??? 104a:?? ?48 89 e2??????????? ??? ?mov??? %rsp,%rdx
??? 104d:?? ?48 83 e4 f0???????? ??? ?and??? $0xfffffffffffffff0,%rsp
??? 1051:?? ?50????????????????? ??? ?push?? %rax
??? 1052:?? ?54????????????????? ??? ?push?? %rsp
??? 1053:?? ?4c 8d 05 56 01 00 00 ?? ?lea??? 0x156(%rip),%r8??????? # 11b0 <__libc_csu_fini>
??? 105a:?? ?48 8d 0d df 00 00 00 ?? ?lea??? 0xdf(%rip),%rcx??????? # 1140 <__libc_csu_init>
??? 1061:?? ?48 8d 3d c1 00 00 00 ?? ?lea??? 0xc1(%rip),%rdi??????? # 1129 <main>
??? 1068:?? ?ff 15 72 2f 00 00?? ??? ?callq? *0x2f72(%rip)??????? # 3fe0 <__libc_start_main@GLIBC_2.2.5>
??? 106e:?? ?f4????????????????? ??? ?hlt?? ?
??? 106f:?? ?90????????????????? ??? ?nop
int main()
{
??? 1129:?? ?f3 0f 1e fa???????? ??? ?endbr64
??? 112d:?? ?55????????????????? ??? ?push?? %rbp
??? 112e:?? ?48 89 e5??????????? ??? ?mov??? %rsp,%rbp
?? ?return 0;
??? 1131:?? ?b8 00 00 00 00????? ??? ?mov??? $0x0,%eax
}
??? 1136:?? ?5d????????????????? ??? ?pop??? %rbp
??? 1137:?? ?c3????????????????? ??? ?retq? ?
??? 1138:?? ?0f 1f 84 00 00 00 00 ?? ?nopl?? 0x0(%rax,%rax,1)
??? 113f:?? ?00
/* __libc_csu_init */
nm aarch64-linux-gnu/libc/usr/lib/crt1.o
0000000000000000 r $d
0000000000000030 t $d
0000000000000000 r $d
0000000000000000 t $x
???????????????? U abort
0000000000000000 D __data_start
0000000000000000 W data_start
0000000000000000 R _IO_stdin_used
??????? U __libc_csu_fini
??????? U __libc_csu_init?? ??? ?// U 表示没有定义的，在这里面使用了，但是在其他库中定义的符号
??????? U __libc_start_main
??????? U main
0000000000000000 T _start
编译时编译器与加入 crt1.o 和源程序一起生成可执行文件。
__libc_csu_init 在 libc 库里。
nm aarch64-linux-gnu/libc/usr/lib/libc.a | grep __libc_csu_init
0000000000000000 T __libc_csu_init??????? // 符号位于代码区
00000000000000c0 T __libc_csu_fini
0000000000000000 T __libc_start_main
/* _start */
程序的真正入口
|