我可以在gdb中用c字符串调用主机进程函数吗？

PyString_InternFromString是具有以下声明的c函数。我可以在gdb中用c字符串调用主机进程函数吗？

PyObject *PyString_InternFromString(const char *cp)

我在gdb中用下面的命令和输出调用了这个函数。

(gdb) p (char *) malloc(10) 
$8 = 0xcfd020 "\210\066▒\364\177" 
(gdb) call strcpy(0xcfd020, "nihao") 
$9 = 13619232 
(gdb) p PyString_InternFromString 
$10 = {PyObject *(const char *)} 0x419158 <PyString_InternFromString> 
(gdb) break PyObject_Malloc 
Breakpoint 1 at 0x418004: PyObject_Malloc. (17 locations) 
(gdb) p 0xcfd020 
$11 = 13619232 
(gdb) p (const char*)0xcfd020 
$12 = 0xcfd020 "nihao" 
(gdb) p ((PyObject * (*)(const char *))0x419158)((const char *)0xcfd020) 
Breakpoint 1, PyString_InternFromString (cp=0x64 <error: Cannot access memory at address 0x64>) at ../Objects/stringobject.c:4783 
4783 ../Objects/stringobject.c: No such file or directory. 
The program being debugged stopped while in a function called from GDB. 
Evaluation of the expression containing the function 
(PyString_InternFromString) will be abandoned. 
When the function is done executing, GDB will silently stop. 
(gdb) bt 
#0 PyString_InternFromString (cp=0x64 <error: Cannot access memory at address 0x64>) at ../Objects/stringobject.c:4783 
#1 0x00007ff489a1a0c0 in ??() 
#2 0x7b752ef9cf7f0a00 in ??() 
#3 0x00007ff489b1b050 in ??() 
#4 0x0000000000000065 in ??() 
#5 0x0000000000000000 in ??() 
(gdb) n 

Program received signal SIGSEGV, Segmentation fault. 
PyObject_Malloc (nbytes=<optimized out>) at ../Objects/obmalloc.c:882 
882  ../Objects/obmalloc.c: No such file or directory. 
(gdb) bt 
#0 PyObject_Malloc (nbytes=<optimized out>) at ../Objects/obmalloc.c:882 
#1 PyString_FromString (str=0x64 <error: Cannot access memory at address  0x64>) at ../Objects/stringobject.c:143 
#2 PyString_InternFromString (cp=0x64 <error: Cannot access memory at address 0x64>) at ../Objects/stringobject.c:4783 
#3 0x00007ff489a1a0c0 in ??() 
#4 0x7b752ef9cf7f0a00 in ??() 
#5 0x00007ff489b1b050 in ??() 
#6 0x0000000000000065 in ??() 
#7 0x0000000000000000 in ??() 
(gdb) info locals 
bp = <optimized out> 
pool = 0x7ff489a0a370 
next = <optimized out> 
size = 9607536 
(gdb) info args 
nbytes = <optimized out> 
(gdb) f 1 
#1 PyString_FromString (str=0x64 <error: Cannot access memory at address 0x64>) at ../Objects/stringobject.c:143 
143  ../Objects/stringobject.c: No such file or directory. 
(gdb) info locals 
size = 100 
op = <optimized out> 
(gdb) info args 
str = 0x64 <error: Cannot access memory at address 0x64> 
(gdb) p ((PyObject * (*)(const char *))0x419158)(&((const char *)0xcfd020)) 
Attempt to take address of value not located in memory. 
(gdb) call strlen("nihaobuhoa") 
$13 = 10

我没有打电话到功能与Segmentation fault。我们可以知道Cannot access memory at address 0x64从输出引起故障。这真令我困惑，我给PyString_InternFromString的是const char *字符串，地址为0xcfd020，但在函数中改为0x64。任何人都知道为什么会发生这种情况？

来源

2017-02-15 ganle hu

我认为你从gdb看到的很多遗漏和令人困惑的信息是因为你正在运行python解释器的优化版本。如果你可以得到一个python的“调试版本”（在Ubuntu上，这是“python2.7-dbg”包），你会发现你不会得到'优化出来的'消息。 –

我试过python调试版本，但没有发生同样的错误。 @MarkPlotnick –

这是因为GDB读符号表PyString_InternFromString的错误的地址。我将python符号表转换为纯文本文件，发现PyString_InternFromString的实际地址与gdb打印的地址不同。

来源

2017-04-06 02:24:50

也许你调用你的函数的方式隐藏了太多GDB的东西。

为什么不直接调用它直接调用它而不是调用铸造指针功能PyString_InternFromString()？您也可以在调用函数时使用C字符串，GDB会自动调用malloc()来创建字符串。

(gdb) # reach a point where every initializations of your call (and 
subcalls) are done. For example, main. 
(gdb) b main 
(gdb) run 
(gdb) p /x PyString_InternFromString("nihao")

注：

此调用隐含取决于它需要的一切，即直接或间接用于全局对象的初始化之前。如果是这种情况，则应在初始化之后首先中断并执行此调用。
从GDB调用函数至少要求首次初始化C运行时，原因与第1点中所述的相同。因此，当您到达main()函数时应执行呼叫。
可以调试通过GDB调用的函数（如错误消息../Objects/stringobject.c: No such file or directory.所述）。下载并specify the directory to GDB，则应能够调试它（调试信息可以是单独的，如果这是你从OS分发库）

来源

2017-02-15 09:00:32

我可以在gdb中用c字符串调用主机进程函数吗？

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