Setting a function signature from script

[james-tate]

For the life of me I cannot fine a script API call for setting a functions signature. I have found, FunctionUtility.updateFunction​(dst,src), and how the GUI does it in EditFunctionSignatureDialog.java. I have been able to setVarArgs(). Does script API call exist for setting a function's arguments? If so can someone point me to it?

[dragonmacher]

I was a bit surprised at just how unobvious this actually was (I would have expected more related methods in the scripting API).

The 'Ghidra Way' of modifying items that are stored in the database, such as a function, involves using an existing Command (or creating one as needed). In this case, you should be using the ghidra.app.cmd.function.ApplyFunctionSignatureCmd class. It has multiple constructors, with the base constructor taking an Address and a FunctionSignature. So, in you script, build a FunctionSignature to you liking and use that to create the above command. Then, use the script API runCommand(command) method to have the new signature applied.

Command objects represent capsules/units of work that get performed together. Further, when a command is run, it is wrapped in a database transaction, which means the entire operation is atomic. Finally, this atomicity allows the undo/redo feature to work correctly.

[james-tate]

Perfect! I found the ApplyFunctionSignatureCmd class, but could not figure out how to run the command after it was constructed. I was looking for an execute(cmd) and totally missed the runCommand(cmd). Thanks!

[astrelsky]

Perfect! I found the ApplyFunctionSignatureCmd class, but could not figure out how to run the command after it was constructed. I was looking for an execute(cmd) and totally missed the runCommand(cmd). Thanks!

Can also use cmd.applyTo(currentProgram)

[crashingstatic]

I wrote a Ghidra script which does the correction automatically.

https://gist.github.com/crashingstatic/71f9ca586e43178fbea3317a93e1df59