Mac上的lldb内存读取错误

Question

我正在试验lldb，并编写了一个简单的C应用程序。我想在终端使用lldb进行调试。当我想看堆栈帧时，出现内存读取错误：

(lldb) target create "./auth_overflow" 
Current executable set to './auth_overflow' (x86_64). 
(lldb) br s -l 25 
Breakpoint 1: where = auth_overflow`main + 69 at auth_overflow.c:25, address = 0x0000000100000e25 
(lldb) br s -l 9 
Breakpoint 2: where = auth_overflow`check_authentication + 47 at auth_overflow.c:9, address = 0x0000000100000d5f 
(lldb) br s -l 16 
Breakpoint 3: where = auth_overflow`check_authentication + 138 at auth_overflow.c:16, address = 0x0000000100000dba 
(lldb) run AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA 
Process 413 launched: './auth_overflow' (x86_64) 
Process 413 stopped 
* thread #1: tid = 0x33d2, 0x0000000100000e25 auth_overflow`main(argc=2, argv=0x00007fff5fbffcc0) + 69 at auth_overflow.c:25, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1 
    frame #0: 0x0000000100000e25 auth_overflow`main(argc=2, argv=0x00007fff5fbffcc0) + 69 at auth_overflow.c:25 
    22    exit(0); 
    23   } 
    24  
-> 25  if(check_authentication(argv[1])) { 
    26    printf("\n-=-=-=-=-=-=-=-=-=-=-=-=-=-\n"); 
    27    printf(" Access Granted.\n"); 
    28    printf("-=-=-=-=-=-=-=-=-=-=-=-=-=-\n"); 
(lldb) re r esp 
    esp = 0x5fbffc70 
(lldb) x/16xw $esp 
error: memory read failed for 0x5fbffc00 
(lldb) 

你有什么建议，我该怎么办？

编辑：其实我不想调试应用程序，只是为了看看它是如何工作在较低的水平。正因为如此，我想看到当前堆栈帧的内容是这样的：

(lldb) x/16xw $esp 
0xbffff7e0: 0xb8000ce0 0x00000002 0x00000000 0xb7fd6ff4 
0xbffff7f0: 0x40f5f7f0 0x00000000 0x00000002 0x08048474 
0xbffff800: 0x08048510 0xbffff874 0x00000001 0x00000001 
0xbffff810: 0xbffff848 0x00000000 0xb8000ff4 0x08048371 
(lldb) 

Answer 1

此：

Current executable set to './auth_overflow' (x86_64). 

显示你是一个64位计算机上。既然如此，你需要64位的rsp寄存器，而不是32位的esp寄存器。 esp将为您提供rsp的最低有效32位内容，在这种情况下，显然不会为您提供有效的地址。

x/16xw $rsp 

是你在找什么。

样品LLDB会议：

paul@horus:~/Documents/src/sandbox$ lldb ./testldb 
(lldb) target create "./testldb" 
Current executable set to './testldb' (x86_64). 
(lldb) list testldb.c 
    1 #include <stdio.h> 
    2  
    3 void func(int i) { 
    4  printf("In func() with value %d\n", i); 
    5 } 
    6  
    7 int main(void) { 
    8  func(3); 
    9  return 0; 
    10 } 
    11 
(lldb) b testldb.c:4 
Breakpoint 1: where = testldb`func + 18 at testldb.c:4, address = 0x0000000100000f22 
(lldb) run 
Process 48270 launched: './testldb' (x86_64) 
Process 48270 stopped 
* thread #1: tid = 0xb8dbca, 0x0000000100000f22 testldb`func(i=3) + 18 at testldb.c:4, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1 
    frame #0: 0x0000000100000f22 testldb`func(i=3) + 18 at testldb.c:4 
    1 #include <stdio.h> 
    2  
    3 void func(int i) { 
-> 4  printf("In func() with value %d\n", i); 
    5 } 
    6  
    7 int main(void) { 
(lldb) frame variable 
(int) i = 3 
(lldb) print &i 
(int *) $0 = 0x00007fff5fbff9dc 
(lldb) register read $rsp 
    rsp = 0x00007fff5fbff9d0 
(lldb) x/16xw $rsp 
0x7fff5fbff9d0: 0x00000000 0x00000000 0x00000000 0x00000003 
0x7fff5fbff9e0: 0x5fbffa00 0x00007fff 0x00000f59 0x00000001 
0x7fff5fbff9f0: 0x5fbffa18 0x00007fff 0x5fc0105e 0x00000000 
0x7fff5fbffa00: 0x5fbffa18 0x00007fff 0x8fdc25fd 0x00007fff 
(lldb)