Can I automate Windbg to attach to a process and set breakpoints?

Question

I am debugging a windows process that crashes if the execution stops for even a few milliseconds. (I don't know how many exactly, but it is definitely less than the time taken by my reflexes to resume the process.)

I know I can launch a windbg session via the command prompt by typing in windbg -p PID which brings up the GUI. But can I then further pass it windbg commands via the command prompt, such as bm *foo!bar* ".frame;gc";g".

Because If I can pass it these commands I can write these down in a .bat file and just run it. There would at least be no delay due to entering (or even copy-pasting) the commands.

score 6 · Accepted Answer · edited May 23 '17 at 12:09

6

Use the -c parameter to pass them:

windbg -p PID -c "bm *foo!bar* .frame;gc;g"

According to the help (found by running windbg /?):

-c "command"

Specifies the initial debugger command to run at start-up. This command must be enclosed in quotation marks. Multiple commands can be separated with semicolons. (If you have a long command list, it may be easier to put them in a script and then use the -c option with the $<, $><, $><, $$>< (Run Script File) command.)

If you are starting a debugging client, this command must be intended for the debugging server. Client-specific commands, such as .lsrcpath, are not allowed.

You may need to play around with the quotes...

Edit: Based on this answer, you might be better off putting the commands into a script file to deal with the quotes:

script.txt (I think this is what you want):

bm *foo!bar* ".frame;gc"
g

Then in your batch file:

windbg -p PID -c "$<full_path_to_script_txt"

edited May 23 '17 at 12:09

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answered Oct 15 '14 at 14:18

Patrick Quirk

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where to put the script.txt file because the error says that windbg is unable to find it. – tmj Oct 15 '14 at 16:34
Anywhere, as long as the directory it is in is the working directory when you start Windbg. – Patrick Quirk Oct 15 '14 at 16:53
Keeping it in the same directory as windbg.exe would do it then? – tmj Oct 15 '14 at 16:55
The command I am typing in is: `windbg -p 19684 -c "$$ – tmj Oct 15 '14 at 17:01
And for a single `$`, that is, `windbg -p 19684 -c "$ – tmj Oct 15 '14 at 17:05
Use a single `$`, and put `script.txt` in the [working directory](http://en.wikipedia.org/wiki/Working_directory). – Patrick Quirk Oct 15 '14 at 17:10
See edits, I don't know how to be clearer without completely describing what a working directory is. – Patrick Quirk Oct 15 '14 at 17:13
Got it to work. Needed to provide it the full directory to the script.txt file, no quotes, no escaping the backward slash. – tmj Oct 15 '14 at 17:17

Can I automate Windbg to attach to a process and set breakpoints?

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