分享下强大的C/C++ 程序调试工具GDB 1.基本调试
这里只列举最最常用的GDB命令。
1.1 启动GDBgdb program：准备调试程序。也可以直接进入gdb，再通过file命令加载。
1.2 添加断点b function：为函数设置断点。b是break的缩写，除了函数名，还可以是地址、当前执行处的+/-偏移等。
1.3 运行程序run args：开始运行程序，run后面可以加程序需要的参数，就像在命令行正常运行时那样。
1.4 单步调试s/n/si/c/kill：s即step in，进入下一行代码执行；n即step next，执行下一行代码但不进入；si即step instruction，执行下一条汇编/CPU指令；c即continue，继续执行直到下一个断点处；kill终止调试；quit退出GDB。
1.5 打印调试信息bt：bt是backtrace的缩写，打印当前所在函数的堆栈路径。
info frame id：打印选中的栈帧的信息。
info args：打印选中栈帧的参数。
print variable：打印指定变量的值。
list：列出相应的源代码。
info registers：查看所有寄存器的值。
还有个更灵活强大的是直接打印%esp开始的前N个元素，例如打印栈上前10个元素就是：x/10x $sp。
2.GDB实战下面是一个使用了上述命令的实战例子：
[root@ bufbomb]# gdb bufbomb GNU gdb (GDB) Red Hat Enterprise Linux (7.2-75.el6) Copyright (C) 2010 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-RedHat-linux-gnu". For bug reporting instructions, please see: <>... Reading symbols from /root/Temp/bufbomb/bufbomb...done. (gdb) b getbuf Breakpoint 1 at 0x8048ad6 (gdb) run -t cdai Starting program: /root/Temp/bufbomb/bufbomb -t cdai Team: cdai Cookie: 0x5e5ee04e Breakpoint 1, 0x08048ad6 in getbuf () Missing separate debuginfos, use: debuginfo-install glibc-2.12-1.149.el6_6.4.i686 (gdb) bt #0 0x08048ad6 in getbuf () #1 0x08048db2 in test () #2 0x08049085 in launch () #3 0x08049257 in main () (gdb) info frame 0 Stack frame at 0xffffb540: eip = 0x8048ad6 in getbuf; saved eip 0x8048db2 called by frame at 0xffffb560 Arglist at 0xffffb538, args: Locals at 0xffffb538, Previous frame's sp is 0xffffb540 Saved registers: ebp at 0xffffb538, eip at 0xffffb53c (gdb) info registers eax 0xc 12 ecx 0xffffb548 -19128 edx 0xc8c340 13157184 ebx 0x0 0 esp 0xffffb510 0xffffb510 ebp 0xffffb538 0xffffb538 esi 0x804b018 134524952 edi 0xffffffff -1 eip 0x8048ad6 0x8048ad6 <getbuf+6> eflags 0x282 [ SF IF ] cs 0x23 35 ss 0x2b 43 ds 0x2b 43 es 0x2b 43 fs 0x0 0 gs 0x63 99 (gdb) x/10x $sp 0xffffb510: 0xf7ffc6b0 0x00000001 0x00000001 0xffffb564 0xffffb520: 0x08048448 0x0804a12c 0xffffb548 0x00c8aff4 0xffffb530: 0x0804b018 0xffffffff (gdb) si 0x08048ad9 in getbuf () (gdb) si 0x08048adc in getbuf () (gdb) si 0x080489c0 in Gets () (gdb) n Single stepping until exit from function Gets, which has no line number information. Type string:123 0x08048ae1 in getbuf () (gdb) si 0x08048ae2 in getbuf () (gdb) c Continuing. Dud: getbuf returned 0x1 Better luck next time Program exited normally. (gdb) quit 3.逆向调试