Step 5 - Using different classes and their predicates about codeql-uboot

[github-learning-lab]

⌨️ Activity: Find all ntoh* macros

1. Edit the file 5_macro_definitions.ql
2. Write a query that finds the definitions of the macros named ntohs, ntohl or ntohll. Use the auto-completion in the Visual Studio Code extension to guide you:
   • Wait a moment after typing from to get a list of available classes in the CodeQL standard library for C/C++. Which class in this list represents macros? Create a variable with this class as its type.
   • In the where section, type <your_variable_name> followed by a dot ., and wait a moment to get the list of predicates available for a value in the variable's type. Hover over each predicate to see the inline documentation.
   • Which predicate will give us the name of a macro?
   • Use the or keyword to combine multiple conditions where you want at least one condition to be met. Here we are interested in three possible macro names.
3. To write a more compact query that searches for all three macros at once, instead of using three cases combined by or you have 2 choices:
   • Use a regular expression. Check out the predicate string::regexpMatch in the built-in predicates for string. CodeQL uses the java.util.Pattern regexp conventions.
   • Use a set literal expression to equate <your_variable_name> to a list of choices <your_variable_name> in ["bar", "baz", "quux"]
4. Once you're happy with the results, submit your solution.

[github-learning-lab]

Congratulations, looks like the query you introduced in 4e14207 finds the correct results!

If you created a pull request, merge it.

Let's continue to the next step.