windbg学习----初始断点

ntdll!LdrpDoDebuggerBreak+0x2c:
7757054e cc              int     3
0:000> kv
ChildEBP RetAddr  Args to Child              
0030f3c8 77550e00 7ffdf000 7ffd3000 775a714c ntdll!LdrpDoDebuggerBreak+0x2c (FPO: [SEH])
0030f528 77536047 0030f59c 774d0000 7121b76b ntdll!LdrpInitializeProcess+0x11a9 (FPO: [2,83,4])
0030f578 775335e9 0030f59c 774d0000 00000000 ntdll!_LdrpInitialize+0x78 (FPO: [SEH])
0030f588 00000000 0030f59c 774d0000 00000000 ntdll!LdrInitializeThunk+0x10 (FPO: [2,0,0]

LdrpInitialize函数是一个新进程的初始线程开始在用户态执行最早代码，LdrpInitializeProcess函数的一个主要任务是加载EXE文件所依赖的动态链接库，在加载每个DLL后，LdrpInitializeProcess都会检查当前进程是否被调试，如果是，则调用用DbgBreakPoint 通知调试器，注意此时并没有调用每个DLL的Dllmain函数

 

初始断点不是调试器可以得到的最早控制机会，如进程创建事件和EXE模块加载事件都会比它早

如：

sxe cpr

然后.restart就可以先断到进程创建的时候
然后强制把PEB的BeingDebugged字段改为0：

0:000> db @$peb
7ffdb000  00 00 01 08 ff ff ff ff-00 00 2e 01 00 00 00 00  ................
7ffdb010  00 00 01 00 00 00 00 00-00 00 00 00 00 00 00 00  ................
7ffdb020  00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00  ................
7ffdb030  00 00 00 00 00 00 00 00-00 00 71 77 00 00 00 00  ..........qw....
7ffdb040  00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00  ................
7ffdb050  00 00 00 00 00 00 00 00-00 00 fa 7f 00 00 fa 7f  ................
7ffdb060  24 00 fd 7f 04 00 00 00-00 00 00 00 00 00 00 00  $...............
7ffdb070  00 80 9b 07 6d e8 ff ff-00 00 10 00 00 20 00 00  ....m........ ..
0:000> eb @$peb+2
7ffdb002 01 0
0
7ffdb003 08 

0:000> db @$peb
7ffdb000  00 00 00 08 ff ff ff ff-00 00 2e 01 00 00 00 00  ................
7ffdb010  00 00 01 00 00 00 00 00-00 00 00 00 00 00 00 00  ................

这样，windbg就不会中断到初始断点了！