@oro-oro
2015-08-18T11:17:20.000000Z
字数 5399
阅读 2170
AndroidARM
$ adb shell
# cd /data/local/tmp
# ./hello
./hello
Hello ARM World!
下面开始调试 hello,尝试反汇编、断点、查看寄存器等操作。
# ./gdb -q hello
./gdb -q hello
Reading symbols from /data/local/tmp/hello...(no debugging symbols found)...done.
gdb disassemble/disas [function-name]
反汇编一下main函数的内容。
(gdb) disas main
disas main
Dump of assembler code for function main:
0x00008258 <+0>: push {r11, lr}
0x0000825c <+4>: add r11, sp, #4
0x00008260 <+8>: sub sp, sp, #32
0x00008264 <+12>: str r0, [r11, #-32]
0x00008268 <+16>: str r1, [r11, #-36] ; 0x24
0x0000826c <+20>: ldr r3, [pc, #52] ; 0x82a8 <main+80>
0x00008270 <+24>: add r3, pc, r3
0x00008274 <+28>: sub r12, r11, #24
0x00008278 <+32>: mov lr, r3
0x0000827c <+36>: ldm lr!, {r0, r1, r2, r3}
0x00008280 <+40>: stmia r12!, {r0, r1, r2, r3}
0x00008284 <+44>: ldr r3, [lr]
0x00008288 <+48>: strb r3, [r12]
0x0000828c <+52>: sub r3, r11, #24
0x00008290 <+56>: mov r0, r3
0x00008294 <+60>: bl 0x8234
0x00008298 <+64>: mov r3, #0
0x0000829c <+68>: mov r0, r3
0x000082a0 <+72>: sub sp, r11, #4
0x000082a4 <+76>: pop {r11, pc}
0x000082a8 <+80>: andeq r0, r0, r4, ror #1
End of assembler dump.
第9行就是main函数的入口,适合第一个断点。
第19行就是函数调用,这里下断点,查看寄存器的值,应该会看到要打印的字符串的。
break/b address/line_number
下断点
(gdb) b *0x0000826c
b *0x0000826c
Breakpoint 1 at 0x826c
(gdb) b *0x00008290 @这里下到18行
b *0x00008290
Breakpoint 2 at 0x8290
info/i
查看信息,可以查看断点信息、寄存器信息等。
i b
查看断点
(gdb) i b
i b
Num Type Disp Enb Address What
1 breakpoint keep y 0x0000826c <main+20>
2 breakpoint keep y 0x00008290 <main+56>
delete/d num
删除断点
(gdb) b *0x000082a8
b *0x000082a8
Breakpoint 3 at 0x82a8
(gdb) i b
i b
Num Type Disp Enb Address What
1 breakpoint keep y 0x0000826c <main+20>
2 breakpoint keep y 0x00008290 <main+56>
3 breakpoint keep y 0x000082a8 <main+80>
(gdb) d 3
d 3
(gdb) i b
i b
Num Type Disp Enb Address What
1 breakpoint keep y 0x0000826c <main+20>
2 breakpoint keep y 0x00008290 <main+56>
run/r
让程序跑起来
(gdb) r
r
Starting program: /data/local/tmp/hello
BFD: /system/bin/linker: warning: sh_link not set for section `.ARM.exidx'
BFD: /system/bin/linker: warning: sh_link not set for section `.ARM.exidx'
warning: Unable to find dynamic linker breakpoint function.
GDB will be unable to debug shared library initializers
and track explicitly loaded dynamic code.
Breakpoint 1, 0x0000826c in main ()
(gdb) n
n
Single stepping until exit from function main,
which has no line number information.
Breakpoint 2, 0x00008290 in main ()
(gdb) i r
i r
r0 0x6c6c6548 1819043144
r1 0x5241206f 1379999855
r2 0x6f57204d 1867980877
r3 0xbeed3c4c -1091748788 @ r3 的值会赋给r0,此时还没有赋值
r4 0x8258 33368
r5 0x1 1
r6 0xafd41504 -1345055484
r7 0xbeed3cac -1091748692
r8 0x0 0
r9 0x0 0
r10 0x0 0
r11 0xbeed3c64 -1091748764
r12 0xbeed3c5c -1091748772
sp 0xbeed3c40 0xbeed3c40
lr 0x836c 33644
pc 0x8290 0x8290 <main+56>
cpsr 0x10 16
(gdb) x 0xbeed3c4c
x 0xbeed3c4c
0xbeed3c4c: "Hello ARM World!"
继续给19行下断点,再查看r0的值。
(gdb) disas main
disas main
Dump of assembler code for function main:
0x00008258 <+0>: push {r11, lr}
0x0000825c <+4>: add r11, sp, #4
0x00008260 <+8>: sub sp, sp, #32
0x00008264 <+12>: str r0, [r11, #-32]
0x00008268 <+16>: str r1, [r11, #-36] ; 0x24
0x0000826c <+20>: ldr r3, [pc, #52] ; 0x82a8 <main+80>
0x00008270 <+24>: add r3, pc, r3
0x00008274 <+28>: sub r12, r11, #24
0x00008278 <+32>: mov lr, r3
0x0000827c <+36>: ldm lr!, {r0, r1, r2, r3}
0x00008280 <+40>: stmia r12!, {r0, r1, r2, r3}
0x00008284 <+44>: ldr r3, [lr]
0x00008288 <+48>: strb r3, [r12]
0x0000828c <+52>: sub r3, r11, #24
=> 0x00008290 <+56>: mov r0, r3
0x00008294 <+60>: bl 0x8234
0x00008298 <+64>: mov r3, #0
0x0000829c <+68>: mov r0, r3
0x000082a0 <+72>: sub sp, r11, #4
0x000082a4 <+76>: pop {r11, pc}
0x000082a8 <+80>: andeq r0, r0, r4, ror #1
End of assembler dump.
(gdb) b *0x00008294
b *0x00008294
Breakpoint 4 at 0x8294
(gdb) n
n
Single stepping until exit from function main,
which has no line number information.
Breakpoint 4, 0x00008294 in main ()
(gdb) i r
i r
r0 0xbeed3c4c -1091748788 @ r0 就是 puts 函数的参数
r1 0x5241206f 1379999855
r2 0x6f57204d 1867980877
r3 0xbeed3c4c -1091748788
r4 0x8258 33368
r5 0x1 1
r6 0xafd41504 -1345055484
r7 0xbeed3cac -1091748692
r8 0x0 0
r9 0x0 0
r10 0x0 0
r11 0xbeed3c64 -1091748764
r12 0xbeed3c5c -1091748772
sp 0xbeed3c40 0xbeed3c40
lr 0x836c 33644
pc 0x8294 0x8294 <main+60>
cpsr 0x10 16
(gdb) x 0xbeed3c4c
x 0xbeed3c4c
0xbeed3c4c: "Hello ARM World!"
where/whe
查看当然程序运行所在的位置
(gdb) whe
whe
#0 0x00008294 in main ()
(gdb)
commands
调试的时候,自动执行某些命令。
譬如,让断点2触发时,自动显示寄存器信息。(第6-16行)
(gdb) i b
i b
Num Type Disp Enb Address What
1 breakpoint keep y 0x0000826c <main+20>
breakpoint already hit 1 time
2 breakpoint keep y 0x00008290 <main+56>
breakpoint already hit 1 time
4 breakpoint keep y 0x00008294 <main+60>
(gdb) commands 2 // -------------------------- 开始 -------------------------
commands 2
Type commands for breakpoint(s) 2, one per line.
End with a line saying just "end".
>i r
i r
>end // -------------------------- 结束 --------------------------
end
(gdb) n
n
Single stepping until exit from function main,
which has no line number information.
Breakpoint 4, 0x00008294 in main ()
(gdb) n
n
Single stepping until exit from function main,
which has no line number information.
Hello ARM World!
0xafd14dba in __libc_init () from /system/lib/libc.so
(gdb) r
r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
y
Starting program: /data/local/tmp/hello
BFD: /system/bin/linker: warning: sh_link not set for section `.ARM.exidx'
BFD: /system/bin/linker: warning: sh_link not set for section `.ARM.exidx'
warning: Unable to find dynamic linker breakpoint function.
GDB will be unable to debug shared library initializers
and track explicitly loaded dynamic code.
Breakpoint 1, 0x0000826c in main ()
(gdb) n
n
Single stepping until exit from function main,
which has no line number information.
Breakpoint 2, 0x00008290 in main ()
r0 0x6c6c6548 1819043144
r1 0x5241206f 1379999855
r2 0x6f57204d 1867980877
r3 0xbefbcc4c -1090794420
r4 0x8258 33368
r5 0x1 1
r6 0xafd41504 -1345055484
r7 0xbefbccac -1090794324
r8 0x0 0
r9 0x0 0
r10 0x0 0
r11 0xbefbcc64 -1090794396
r12 0xbefbcc5c -1090794404
sp 0xbefbcc40 0xbefbcc40
lr 0x836c 33644
pc 0x8290 0x8290 <main+56>
cpsr 0x10 16
(gdb)
continue/c
继续运行,跟next/n
效果差不多。
(gdb) c
c
Continuing.
Breakpoint 4, 0x00008294 in main ()
(gdb) c
c
Continuing.
Hello ARM World!
Program exited normally.
(gdb)