《深入理解计算机系统》中的例子
hello.h
#ifndef HELLO_H
#define HELLO_H
void hello(const char *name);
#endif //HELLO_H hello.c
#include <stdio.h>
void hello(const char *name) {
printf("Hello %s!\n", name);
} main.c
include "hello.h"
int main() {
hello("everyone");
return 0;
} mian.c中引用了hello函数，这里先对hello.c生成 .o 文件，然后再将hello.o 和 main一起加载，合并成一个可执行文件
静态链接
gcc -c hello.c将hello.o打包成一个静态库，再编译main.c，跟静态库文件一起合并成一个可执行文件，最后运行
通过gdb反汇编hello文件，静态链接是将main函数和hello函数都打进这个hello程序里面了
ar cr libmyhello.a hello.o
gcc -o hello main.c -L. -lmyhello
./hello
Hello everyone! gdb反汇编hello程序
(gdb) disas
_DYNAMIC __do_global_dtors_aux_fini_array_entry __libc_start_main deregister_tm_clones
_GLOBAL_OFFSET_TABLE_ __dso_handle [email protected] frame_dummy
_IO_stdin_used __frame_dummy_init_array_entry __libc_start_main@plt hello
__FRAME_END__ __gmon_start__ _edata main
__JCR_END__ [email protected] _end printf
__JCR_LIST__ __gmon_start__@plt _fini [email protected]
__TMC_END__ __init_array_end _init printf@plt
__bss_start __init_array_start _start register_tm_clones
__data_start __libc_csu_fini completed.6354
__do_global_dtors_aux __libc_csu_init data_start
(gdb) disas main《程序员的自我修养--链接，加载和库》中的例子
a.c文件内容
extern int shared;
int main() {
int a = 100;
swap(&a, &shared);
} b.c文件内容
int shared = 1;
void swap(int *a, int *b) {
*a ^= *b ^= *a ^= *b;
} 将a.o和b.o链接起来，生成 ab 可执行文件
ld a.o b.o -e main -o ab空间分配策略，简单合并，a.o，b.o，c.o将各自的段依次叠加起来输出到一个目标文件中
更好的实现方案，将a.o，b.o，c.o中相同的段合并到一起
a.o文件 objdump -d 结果
这里的 mov $0x0，%esi 还有 callq 25<main+0x25> 这两个指令对应的地址都是假地址
只是一个占位符，后面到真正链接的时候才会确定最终地址
a.o: file format elf64-x86-64
Disassembly of section .text:
0000000000000000 <main>:
0: 55 push %rbp
1: 48 89 e5 mov %rsp,%rbp
4: 48 83 ec 10 sub $0x10,%rsp
8: c7 45 fc 64 00 00 00 movl $0x64,-0x4(%rbp)
f: 48 8d 45 fc lea -0x4(%rbp),%rax
13: be 00 00 00 00 mov $0x0,%esi
18: 48 89 c7 mov %rax,%rdi
1b: b8 00 00 00 00 mov $0x0,%eax
20: e8 00 00 00 00 callq 25 <main+0x25>
25: c9 leaveq
26: c3 retq objdump -r a.o的结果
a.o: file format elf64-x86-64
RELOCATION RECORDS FOR [.text]:
OFFSET TYPE VALUE
0000000000000014 R_X86_64_32 shared
0000000000000021 R_X86_64_PC32 swap-0x0000000000000004
RELOCATION RECORDS FOR [.eh_frame]:
OFFSET TYPE VALUE
0000000000000020 R_X86_64_PC32 .text这里的R_X86_64_32是绝对寻址修正，之后连接器会将这两个地址修改成真正可以加载的地址
gdb反汇编ab的main函数
蓝色标注的两行就是重新定位地址，第一个是赋值语言重新定位了地址，第二个的函数调用也重新赋值了地址
Dump of assembler code for function main:
0x00000000004004ed <+0>: push %rbp
0x00000000004004ee <+1>: mov %rsp,%rbp
0x00000000004004f1 <+4>: sub $0x10,%rsp
0x00000000004004f5 <+8>: movl $0x64,-0x4(%rbp)
0x00000000004004fc <+15>: lea -0x4(%rbp),%rax
0x0000000000400500 <+19>: mov $0x60102c,%esi
0x0000000000400505 <+24>: mov %rax,%rdi
0x0000000000400508 <+27>: mov $0x0,%eax
0x000000000040050d <+32>: callq 0x400514 <swap>
0x0000000000400512 <+37>: leaveq
0x0000000000400513 <+38>: retq
End of assembler dump.一个简单的hello.c程序，用 gcc --verbose编译出来的内容如下
gcc -static --verbose -fno-builtin hello.c
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-linker-hash-style=gnu --enable-languages=c,c++,objc,obj-c++,java,fortran,ada,go,lto --enable-plugin --enable-initfini-array --disable-libgcj --with-isl=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/isl-install --with-cloog=/builddir/build/BUILD/gcc-4.8.5-20150702/obj-x86_64-redhat-linux/cloog-install --enable-gnu-indirect-function --with-tune=generic --with-arch_32=x86-64 --build=x86_64-redhat-linux
Thread model: posix
gcc version 4.8.5 20150623 (Red Hat 4.8.5-16) (GCC)
COLLECT_GCC_OPTIONS='-v' '-mtune=generic' '-march=x86-64'
/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/cc1 -quiet -v hello.c -quiet -dumpbase hello.c -mtune=generic -march=x86-64 -auxbase hello -version -o /tmp/cczX7TMQ.s
GNU C (GCC) version 4.8.5 20150623 (Red Hat 4.8.5-16) (x86_64-redhat-linux)
compiled by GNU C version 4.8.5 20150623 (Red Hat 4.8.5-16), GMP version 6.0.0, MPFR version 3.1.1, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=97 --param ggc-min-heapsize=127051
ignoring nonexistent directory "/usr/lib/gcc/x86_64-redhat-linux/4.8.5/include-fixed"
ignoring nonexistent directory "/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../x86_64-redhat-linux/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/lib/gcc/x86_64-redhat-linux/4.8.5/include
/usr/local/include
/usr/include
End of search list.
GNU C (GCC) version 4.8.5 20150623 (Red Hat 4.8.5-16) (x86_64-redhat-linux)
compiled by GNU C version 4.8.5 20150623 (Red Hat 4.8.5-16), GMP version 6.0.0, MPFR version 3.1.1, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=97 --param ggc-min-heapsize=127051
Compiler executable checksum: 25c276d835072ed72bab97eea8b3b665
COLLECT_GCC_OPTIONS='-v' '-mtune=generic' '-march=x86-64'
as -v --64 -o /tmp/ccoPro2p.o /tmp/cczX7TMQ.s
GNU assembler version 2.25.1 (x86_64-redhat-linux) using BFD version version 2.25.1-32.base.el7_4.2
COMPILER_PATH=/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/:/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/:/usr/libexec/gcc/x86_64-redhat-linux/:/usr/lib/gcc/x86_64-redhat-linux/4.8.5/:/usr/lib/gcc/x86_64-redhat-linux/
LIBRARY_PATH=/usr/lib/gcc/x86_64-redhat-linux/4.8.5/:/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/:/lib/../lib64/:/usr/lib/../lib64/:/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-v' '-mtune=generic' '-march=x86-64'
/usr/libexec/gcc/x86_64-redhat-linux/4.8.5/collect2 --build-id --no-add-needed --eh-frame-hdr --hash-style=gnu -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crt1.o /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crti.o /usr/lib/gcc/x86_64-redhat-linux/4.8.5/crtbegin.o -L/usr/lib/gcc/x86_64-redhat-linux/4.8.5 -L/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64 -L/lib/../lib64 -L/usr/lib/../lib64 -L/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../.. /tmp/ccoPro2p.o -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed /usr/lib/gcc/x86_64-redhat-linux/4.8.5/crtend.o /usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crtn.o查看静态链接库里面的 .o文件
ar -t [xxx.a]
假设有一个hello.c文件，用了io库中的printf函数，单独将这个printf.o从libc.a 中拷贝出来，再链接是不行的
printf.o 又引用了其他 .o文件，而那些 .o文件又引用其他的，这些就没完了
一个没有main函数的程序，利用汇编和中断实现 hello world
char* str = "Hello World!\n";
void print() {
//write函数原型 write(int filedesc, char* buffer, int size);
//write的系统调用为4，即rax=4，
//第一个参数是fd终端的fd是0 即bx=0，第二个参数是写缓冲地址也就是str字符串，传递给rbx
//第三个参数是是字符串长度，这里是13传递给rdx，最后通过0x80中断实现
asm("movq $13,%%rdx \n\t"
"movq %0,%%rcx \n\t"
"movq $0,%%rbx\n\t"
"movq $4,%%rax \n\t"
"int $0x80 \n\t"
::"r"(str):"rdx","rcx","rbx");
}
void exit() {
//rbx表示退出的状态码为42，exit的系统调用为1即rax=1，这里也使用0x80中断调用
asm("movq $42,%rbx \n\t"
"movq $1,%rax \n\t"
"int $0x80 \n\t"
);
}
void nomain() {
print();
exit();
} 编译并生成ELF文件，-fno-builtin 是禁止编译器优化，gcc会将一个参数的printf() 优化成puts
gcc -c -fno-builtin TinyHelloWorld.c
ld -static -e nomain -o TinyHelloWorld TinyHelloWorld.o
./TinyHelloWorld 最终会产生的TinyHelloWorld会有如下sectioin
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
[ 0] NULL 0000000000000000 00000000
0000000000000000 0000000000000000 0 0 0
[ 1] .text PROGBITS 00000000004000e8 000000e8
0000000000000059 0000000000000000 AX 0 0 1
[ 2] .rodata PROGBITS 0000000000400141 00000141
000000000000000e 0000000000000000 A 0 0 1
[ 3] .eh_frame PROGBITS 0000000000400150 00000150
0000000000000078 0000000000000000 A 0 0 8
[ 4] .data PROGBITS 0000000000601000 00001000
0000000000000008 0000000000000000 WA 0 0 8
[ 5] .comment PROGBITS 0000000000000000 00001008
000000000000002d 0000000000000001 MS 0 0 1
[ 6] .shstrtab STRTAB 0000000000000000 00001035
0000000000000042 0000000000000000 0 0 1
[ 7] .symtab SYMTAB 0000000000000000 00001078
0000000000000150 0000000000000018 8 7 8
[ 8] .strtab STRTAB 0000000000000000 000011c8
0000000000000040 0000000000000000 0 0 1编写自定义的脚本链接文件，去掉多余的section
这里的意思是程序的入口函数是 nomain
起始地址是 0x08048000 + SIZEOF_HEADERS
然后将 .text， .data， .rodata合并成 tinytext段
最后丢弃 .comment等段
ENTRY(nomain)
SECTIONS
{
. = 0x08048000 + SIZEOF_HEADERS;
tinytext : { *(.text) *(.data) *(.rodata)}
/DISCARD/ :{ *(.comment) *(.eh_frame) *(.shstrtab) *(.symtab) *(.strtab)}
} 链接命令
ld -static -T tiny.lds -o TinyHello -s TinyHelloWorld.o最后生成的TinyHello的section如下，但奇怪的是最后生存的TinyHello却有 295424字节，比没去掉多余段的时候还大很多，用hexdump看了结果，貌似里面的内容没有TinyHelloWorld(就是那个没去掉多余段的文件)多，显示这么多字节可能是系统的问题
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
[ 0] NULL 0000000000000000 00000000
0000000000000000 0000000000000000 0 0 0
[ 1] tinytext PROGBITS 00000000080480b0 000480b0
0000000000000076 0000000000000000 WAX 0 0 8
[ 2] .shstrtab STRTAB 0000000000000000 00048126
0000000000000014 0000000000000000 0 0 1参考
《程序员的自我修养-链接,装载与库》
附录
ab ELF文件 执行 readelf -a 后的结果
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: EXEC (Executable file)
Machine: Advanced Micro Devices X86-64
Version: 0x1
Entry point address: 0x400400
Start of program headers: 64 (bytes into file)
Start of section headers: 6632 (bytes into file)
Flags: 0x0
Size of this header: 64 (bytes)
Size of program headers: 56 (bytes)
Number of program headers: 9
Size of section headers: 64 (bytes)
Number of section headers: 30
Section header string table index: 27
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
[ 0] NULL 0000000000000000 00000000
0000000000000000 0000000000000000 0 0 0
[ 1] .interp PROGBITS 0000000000400238 00000238
000000000000001c 0000000000000000 A 0 0 1
[ 2] .note.ABI-tag NOTE 0000000000400254 00000254
0000000000000020 0000000000000000 A 0 0 4
[ 3] .note.gnu.build-i NOTE 0000000000400274 00000274
0000000000000024 0000000000000000 A 0 0 4
[ 4] .gnu.hash GNU_HASH 0000000000400298 00000298
000000000000001c 0000000000000000 A 5 0 8
[ 5] .dynsym DYNSYM 00000000004002b8 000002b8
0000000000000048 0000000000000018 A 6 1 8
[ 6] .dynstr STRTAB 0000000000400300 00000300
0000000000000038 0000000000000000 A 0 0 1
[ 7] .gnu.version VERSYM 0000000000400338 00000338
0000000000000006 0000000000000002 A 5 0 2
[ 8] .gnu.version_r VERNEED 0000000000400340 00000340
0000000000000020 0000000000000000 A 6 1 8
[ 9] .rela.dyn RELA 0000000000400360 00000360
0000000000000018 0000000000000018 A 5 0 8
[10] .rela.plt RELA 0000000000400378 00000378
0000000000000030 0000000000000018 AI 5 12 8
[11] .init PROGBITS 00000000004003a8 000003a8
000000000000001a 0000000000000000 AX 0 0 4
[12] .plt PROGBITS 00000000004003d0 000003d0
0000000000000030 0000000000000010 AX 0 0 16
[13] .text PROGBITS 0000000000400400 00000400
00000000000001d2 0000000000000000 AX 0 0 16
[14] .fini PROGBITS 00000000004005d4 000005d4
0000000000000009 0000000000000000 AX 0 0 4
[15] .rodata PROGBITS 00000000004005e0 000005e0
0000000000000010 0000000000000000 A 0 0 8
[16] .eh_frame_hdr PROGBITS 00000000004005f0 000005f0
000000000000003c 0000000000000000 A 0 0 4
[17] .eh_frame PROGBITS 0000000000400630 00000630
0000000000000114 0000000000000000 A 0 0 8
[18] .init_array INIT_ARRAY 0000000000600e10 00000e10
0000000000000008 0000000000000000 WA 0 0 8
[19] .fini_array FINI_ARRAY 0000000000600e18 00000e18
0000000000000008 0000000000000000 WA 0 0 8
[20] .jcr PROGBITS 0000000000600e20 00000e20
0000000000000008 0000000000000000 WA 0 0 8
[21] .dynamic DYNAMIC 0000000000600e28 00000e28
00000000000001d0 0000000000000010 WA 6 0 8
[22] .got PROGBITS 0000000000600ff8 00000ff8
0000000000000008 0000000000000008 WA 0 0 8
[23] .got.plt PROGBITS 0000000000601000 00001000
0000000000000028 0000000000000008 WA 0 0 8
[24] .data PROGBITS 0000000000601028 00001028
0000000000000008 0000000000000000 WA 0 0 4
[25] .bss NOBITS 0000000000601030 00001030
0000000000000008 0000000000000000 WA 0 0 1
[26] .comment PROGBITS 0000000000000000 00001030
000000000000002d 0000000000000001 MS 0 0 1
[27] .shstrtab STRTAB 0000000000000000 0000105d
0000000000000108 0000000000000000 0 0 1
[28] .symtab SYMTAB 0000000000000000 00001168
0000000000000648 0000000000000018 29 46 8
[29] .strtab STRTAB 0000000000000000 000017b0
0000000000000231 0000000000000000 0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings), l (large)
I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
O (extra OS processing required) o (OS specific), p (processor specific)
There are no section groups in this file.
Program Headers:
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
PHDR 0x0000000000000040 0x0000000000400040 0x0000000000400040
0x00000000000001f8 0x00000000000001f8 R E 8
INTERP 0x0000000000000238 0x0000000000400238 0x0000000000400238
0x000000000000001c 0x000000000000001c R 1
[Requesting program interpreter: /lib64/ld-linux-x86-64.so.2]
LOAD 0x0000000000000000 0x0000000000400000 0x0000000000400000
0x0000000000000744 0x0000000000000744 R E 200000
LOAD 0x0000000000000e10 0x0000000000600e10 0x0000000000600e10
0x0000000000000220 0x0000000000000228 RW 200000
DYNAMIC 0x0000000000000e28 0x0000000000600e28 0x0000000000600e28
0x00000000000001d0 0x00000000000001d0 RW 8
NOTE 0x0000000000000254 0x0000000000400254 0x0000000000400254
0x0000000000000044 0x0000000000000044 R 4
GNU_EH_FRAME 0x00000000000005f0 0x00000000004005f0 0x00000000004005f0
0x000000000000003c 0x000000000000003c R 4
GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000
0x0000000000000000 0x0000000000000000 RW 10
GNU_RELRO 0x0000000000000e10 0x0000000000600e10 0x0000000000600e10
0x00000000000001f0 0x00000000000001f0 R 1
Section to Segment mapping:
Segment Sections...
00
01 .interp
02 .interp .note.ABI-tag .note.gnu.build-id .gnu.hash .dynsym .dynstr .gnu.version .gnu.version_r .rela.dyn .rela.plt .init .plt .text .fini .rodata .eh_frame_hdr .eh_frame
03 .init_array .fini_array .jcr .dynamic .got .got.plt .data .bss
04 .dynamic
05 .note.ABI-tag .note.gnu.build-id
06 .eh_frame_hdr
07
08 .init_array .fini_array .jcr .dynamic .got
Dynamic section at offset 0xe28 contains 24 entries:
Tag Type Name/Value
0x0000000000000001 (NEEDED) Shared library: [libc.so.6]
0x000000000000000c (INIT) 0x4003a8
0x000000000000000d (FINI) 0x4005d4
0x0000000000000019 (INIT_ARRAY) 0x600e10
0x000000000000001b (INIT_ARRAYSZ) 8 (bytes)
0x000000000000001a (FINI_ARRAY) 0x600e18
0x000000000000001c (FINI_ARRAYSZ) 8 (bytes)
0x000000006ffffef5 (GNU_HASH) 0x400298
0x0000000000000005 (STRTAB) 0x400300
0x0000000000000006 (SYMTAB) 0x4002b8
0x000000000000000a (STRSZ) 56 (bytes)
0x000000000000000b (SYMENT) 24 (bytes)
0x0000000000000015 (DEBUG) 0x0
0x0000000000000003 (PLTGOT) 0x601000
0x0000000000000002 (PLTRELSZ) 48 (bytes)
0x0000000000000014 (PLTREL) RELA
0x0000000000000017 (JMPREL) 0x400378
0x0000000000000007 (RELA) 0x400360
0x0000000000000008 (RELASZ) 24 (bytes)
0x0000000000000009 (RELAENT) 24 (bytes)
0x000000006ffffffe (VERNEED) 0x400340
0x000000006fffffff (VERNEEDNUM) 1
0x000000006ffffff0 (VERSYM) 0x400338
0x0000000000000000 (NULL) 0x0
Relocation section '.rela.dyn' at offset 0x360 contains 1 entries:
Offset Info Type Sym. Value Sym. Name + Addend
000000600ff8 000200000006 R_X86_64_GLOB_DAT 0000000000000000 __gmon_start__ + 0
Relocation section '.rela.plt' at offset 0x378 contains 2 entries:
Offset Info Type Sym. Value Sym. Name + Addend
000000601018 000100000007 R_X86_64_JUMP_SLO 0000000000000000 __libc_start_main + 0
000000601020 000200000007 R_X86_64_JUMP_SLO 0000000000000000 __gmon_start__ + 0
The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported.
Symbol table '.dynsym' contains 3 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000000000 0 FUNC GLOBAL DEFAULT UND __libc_start_main@GLIBC_2.2.5 (2)
2: 0000000000000000 0 NOTYPE WEAK DEFAULT UND __gmon_start__
Symbol table '.symtab' contains 67 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000400238 0 SECTION LOCAL DEFAULT 1
2: 0000000000400254 0 SECTION LOCAL DEFAULT 2
3: 0000000000400274 0 SECTION LOCAL DEFAULT 3
4: 0000000000400298 0 SECTION LOCAL DEFAULT 4
5: 00000000004002b8 0 SECTION LOCAL DEFAULT 5
6: 0000000000400300 0 SECTION LOCAL DEFAULT 6
7: 0000000000400338 0 SECTION LOCAL DEFAULT 7
8: 0000000000400340 0 SECTION LOCAL DEFAULT 8
9: 0000000000400360 0 SECTION LOCAL DEFAULT 9
10: 0000000000400378 0 SECTION LOCAL DEFAULT 10
11: 00000000004003a8 0 SECTION LOCAL DEFAULT 11
12: 00000000004003d0 0 SECTION LOCAL DEFAULT 12
13: 0000000000400400 0 SECTION LOCAL DEFAULT 13
14: 00000000004005d4 0 SECTION LOCAL DEFAULT 14
15: 00000000004005e0 0 SECTION LOCAL DEFAULT 15
16: 00000000004005f0 0 SECTION LOCAL DEFAULT 16
17: 0000000000400630 0 SECTION LOCAL DEFAULT 17
18: 0000000000600e10 0 SECTION LOCAL DEFAULT 18
19: 0000000000600e18 0 SECTION LOCAL DEFAULT 19
20: 0000000000600e20 0 SECTION LOCAL DEFAULT 20
21: 0000000000600e28 0 SECTION LOCAL DEFAULT 21
22: 0000000000600ff8 0 SECTION LOCAL DEFAULT 22
23: 0000000000601000 0 SECTION LOCAL DEFAULT 23
24: 0000000000601028 0 SECTION LOCAL DEFAULT 24
25: 0000000000601030 0 SECTION LOCAL DEFAULT 25
26: 0000000000000000 0 SECTION LOCAL DEFAULT 26
27: 0000000000000000 0 FILE LOCAL DEFAULT ABS crtstuff.c
28: 0000000000600e20 0 OBJECT LOCAL DEFAULT 20 __JCR_LIST__
29: 0000000000400430 0 FUNC LOCAL DEFAULT 13 deregister_tm_clones
30: 0000000000400460 0 FUNC LOCAL DEFAULT 13 register_tm_clones
31: 00000000004004a0 0 FUNC LOCAL DEFAULT 13 __do_global_dtors_aux
32: 0000000000601030 1 OBJECT LOCAL DEFAULT 25 completed.6354
33: 0000000000600e18 0 OBJECT LOCAL DEFAULT 19 __do_global_dtors_aux_fin
34: 00000000004004c0 0 FUNC LOCAL DEFAULT 13 frame_dummy
35: 0000000000600e10 0 OBJECT LOCAL DEFAULT 18 __frame_dummy_init_array_
36: 0000000000000000 0 FILE LOCAL DEFAULT ABS a.c
37: 0000000000000000 0 FILE LOCAL DEFAULT ABS b.c
38: 0000000000000000 0 FILE LOCAL DEFAULT ABS crtstuff.c
39: 0000000000400740 0 OBJECT LOCAL DEFAULT 17 __FRAME_END__
40: 0000000000600e20 0 OBJECT LOCAL DEFAULT 20 __JCR_END__
41: 0000000000000000 0 FILE LOCAL DEFAULT ABS
42: 0000000000600e18 0 NOTYPE LOCAL DEFAULT 18 __init_array_end
43: 0000000000600e28 0 OBJECT LOCAL DEFAULT 21 _DYNAMIC
44: 0000000000600e10 0 NOTYPE LOCAL DEFAULT 18 __init_array_start
45: 0000000000601000 0 OBJECT LOCAL DEFAULT 23 _GLOBAL_OFFSET_TABLE_
46: 00000000004005d0 2 FUNC GLOBAL DEFAULT 13 __libc_csu_fini
47: 0000000000000000 0 NOTYPE WEAK DEFAULT UND _ITM_deregisterTMCloneTab
48: 0000000000601028 0 NOTYPE WEAK DEFAULT 24 data_start
49: 0000000000601030 0 NOTYPE GLOBAL DEFAULT 24 _edata
50: 00000000004005d4 0 FUNC GLOBAL DEFAULT 14 _fini
51: 0000000000000000 0 FUNC GLOBAL DEFAULT UND __libc_start_main@@GLIBC_
52: 0000000000601028 0 NOTYPE GLOBAL DEFAULT 24 __data_start
53: 0000000000000000 0 NOTYPE WEAK DEFAULT UND __gmon_start__
54: 00000000004005e8 0 OBJECT GLOBAL HIDDEN 15 __dso_handle
55: 00000000004005e0 4 OBJECT GLOBAL DEFAULT 15 _IO_stdin_used
56: 0000000000400560 101 FUNC GLOBAL DEFAULT 13 __libc_csu_init
57: 0000000000601038 0 NOTYPE GLOBAL DEFAULT 25 _end
58: 0000000000400400 0 FUNC GLOBAL DEFAULT 13 _start
59: 0000000000601030 0 NOTYPE GLOBAL DEFAULT 25 __bss_start
60: 00000000004004ed 39 FUNC GLOBAL DEFAULT 13 main
61: 0000000000000000 0 NOTYPE WEAK DEFAULT UND _Jv_RegisterClasses
62: 0000000000601030 0 OBJECT GLOBAL HIDDEN 24 __TMC_END__
63: 0000000000000000 0 NOTYPE WEAK DEFAULT UND _ITM_registerTMCloneTable
64: 0000000000400514 74 FUNC GLOBAL DEFAULT 13 swap
65: 00000000004003a8 0 FUNC GLOBAL DEFAULT 11 _init
66: 000000000060102c 4 OBJECT GLOBAL DEFAULT 24 shared
Version symbols section '.gnu.version' contains 3 entries:
Addr: 0000000000400338 Offset: 0x000338 Link: 5 (.dynsym)
000: 0 (*local*) 2 (GLIBC_2.2.5) 0 (*local*)
Version needs section '.gnu.version_r' contains 1 entries:
Addr: 0x0000000000400340 Offset: 0x000340 Link: 6 (.dynstr)
000000: Version: 1 File: libc.so.6 Cnt: 1
0x0010: Name: GLIBC_2.2.5 Flags: none Version: 2
Displaying notes found at file offset 0x00000254 with length 0x00000020:
Owner Data size Description
GNU 0x00000010 NT_GNU_ABI_TAG (ABI version tag)
OS: Linux, ABI: 2.6.32
Displaying notes found at file offset 0x00000274 with length 0x00000024:
Owner Data size Description
GNU 0x00000014 NT_GNU_BUILD_ID (unique build ID bitstring)
Build ID: a7c7f8327b46ef5d307fcbc17fb0ebf062d3cf97