CODEWITHSUNDEEP
windbg
Kizaru
Kizaru

Reputation: 2513

Changing current directory and command line arguments to CDB debugging process

I've used gdb for a lot of my work in university and at my current job, but I need to learn how to use CDB and WinDBG for development on Windows. I'd prefer to use CDB because there is a nice mode for it in Emacs.

  1. How can I change the current directory after starting CDB? This is useful because the current directory defaults to the executable directory (cdb C:/dev/myexe.exe would give a current dir=c:/dev, although I launched cdb from C:/testdir), but I may have a testing directory on a different drive which I'd prefer to use as the working directory. Or I may have multiple testing directories and I'd like to switch between them easily without losing breakpoints for the process. Changing the working directory can be done in GDB using cd. How can this be done in CDB?

  2. Suppose I start debugging a new process using cdb my.exe arg1 arg2 and after a few minutes of setting breakpoints and code stepping, I realize I should specify an additional argument. In GDB, I can set the command line arguments whenever I run the process (r arg1 arg2 newarg3 ...). My breakpoints and everything in the workspace stay the same. Is it possible to do this in CDB? It looks like I need to save the workspace, restart CDB with the new arguments for the debugging process, and then load the workspace to get the breakpoints, which is significantly more work than just issuing a run command.

I haven't found answers for these after searching on and off the past few weeks, and I'd really like to get away from Visual Studio debugging.

Edit: Clarified #1 and #2

Upvotes: 2

Views: 4589

Answers (1)

jcopenha
jcopenha

Reputation: 3975

Well, it isn't as easy as in GDB but it is possible in CDB.

To change the working directory and maintain the breakpoints you have to .kill the process, tell it where to startup using .creatdir, and restart the process with .create.

For example:

 0:000> bp CreateFileW 
 0:000> bl  0 e 750316af     
 0001 (0001)  0:**** kernel32!CreateFileW 
 0:000> .kill 
 Terminated.  Exit thread and process events will occur.     
 0:000> .createdir d:\dev 
 Process creation dir: d:\dev 
 Process will inherit handles   
 0:000> .create c:\windows\system32\notepad.exe 
 CommandLine: c:\windows\system32\notepad.exe 
 Starting directory: d:\dev 
 Create will proceed with next execution 
 0:000> g 
 Symbol search path is: SRV*d:\symbols*http://msdl.microsoft.com/download/symbols 
 Executable search path is:  ModLoad: 00880000 008b0000   notepad.exe eax=00000000   
 ebx=00000000 ecx=25c50000 edx=0009dc08 esi=fffffffe edi=00000000 eip=774d0fac 
 esp=000df398 ebp=000df3c4 iopl=0         nv up ei pl zr na pe nc cs=0023  ss=002b  
 ds=002b  es=002b  fs=0053  gs=002b          efl=00000244 
 ntdll!LdrpDoDebuggerBreak+0x2d: 774d0fac 8975fc          mov     dword ptr [ebp-4],esi ss:002b:000df3c0=00000000 
 0:000> bl  0 e 750316af     
 0001 (0001)  0:**** kernel32!CreateFileW 
 0:000> g

To restart with different arguments you do the same .kill and then pass new arguments to the .create command.

If you are going to be doing this a lot then I would invest some time in writing a script that made this multi-step process easier.

Upvotes: 6

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