MCQs on Customizing Lua Behavior | Lua
1. Customizing the Lua Interpreter
- Which function is used to modify the behavior of Lua’s garbage collector?
- A)
collectgarbage() - B)
setgarbage() - C)
gcmodify() - D)
garbagecontrol()
- A)
- In Lua, what is the purpose of the
load()function?- A) Load external libraries
- B) Compile Lua code from a string
- C) Execute a file
- D) Load a Lua module
- What is the primary purpose of modifying the Lua interpreter?
- A) Increase speed
- B) Debug Lua scripts
- C) Customize runtime behavior
- D) Modify the Lua syntax
- Which of the following can be modified in the Lua interpreter to change Lua’s execution environment?
- A) Global environment
- B) Error handling
- C) Garbage collection
- D) All of the above
- What is the effect of setting
package.loadedto a custom value in Lua?- A) It changes the location of Lua libraries
- B) It affects the module loading behavior
- C) It deletes loaded modules
- D) It prevents the execution of external files
2. Using Hooks with the Debug Library
- Which function in the
debuglibrary sets a hook for Lua’s execution?- A)
debug.sethook() - B)
debug.settrace() - C)
debug.setcallback() - D)
debug.execute()
- A)
- What does the
debug.sethook()function allow you to do?- A) Set breakpoints during execution
- B) Set the number of iterations for a loop
- C) Monitor function calls, returns, and line changes
- D) Prevent the execution of functions
- What are the four hook types available in Lua’s
debuglibrary?- A) Line, call, return, and closure
- B) Line, call, return, and count
- C) Call, exit, return, and callback
- D) Break, return, entry, and exit
- How does Lua’s
debuglibrary help in debugging scripts?- A) By logging execution flow and state
- B) By modifying Lua’s core behavior
- C) By allowing execution without modification
- D) By halting the script automatically
- Which of the following is true when using the
debuglibrary’s hook functionality?- A) Hooks are automatically cleared after execution
- B) Hooks run before the Lua interpreter is modified
- C) Hooks monitor program flow but cannot stop execution
- D) Hooks do not provide information on function arguments
3. Lua’s Sandboxing for Secure Execution
- What is Lua sandboxing primarily used for?
- A) Improving performance in high-load systems
- B) Isolating potentially dangerous code execution
- C) Enabling multithreading in Lua
- D) Securing Lua syntax errors
- Which function is commonly used to prevent access to dangerous operations in Lua?
- A)
os.exit() - B)
debug.getupvalue() - C)
loadstring() - D)
setfenv()
- A)
- How does Lua’s
setfenv()function contribute to sandboxing?- A) Modifies the global environment for a function
- B) Disables access to specific modules
- C) Encrypts Lua bytecode
- D) Optimizes the performance of Lua code
- In a Lua sandbox, which of the following is typically restricted?
- A) Reading from external files
- B) Modifying global variables
- C) Accessing the network
- D) All of the above
- Which Lua function allows you to safely execute a string of code within a controlled environment?
- A)
load() - B)
dofile() - C)
require() - D)
loadstring()
- A)
- What is the purpose of Lua’s
package.loadedin a sandbox environment?- A) Prevent libraries from being loaded into memory
- B) Manage external library installation
- C) Track function calls
- D) Secure user input
- Which of the following is NOT a common use case for sandboxing Lua?
- A) Running untrusted code safely
- B) Allowing code to access global resources
- C) Isolating execution from the host environment
- D) Preventing system resource exhaustion
- Which of the following best describes the
loadfile()function in a sandboxed environment?- A) It loads Lua code from a file, but restricts access to sensitive system resources
- B) It executes Lua code directly from a string
- C) It imports an external module
- D) It is a deprecated function in sandboxing
- In a Lua sandbox, which of the following would you likely disable for security reasons?
- A)
io.read() - B)
os.execute() - C)
debug.traceback() - D) All of the above
- A)
- Which approach is commonly used to prevent Lua code from accessing certain libraries in a sandbox?
- A) Modifying the
requirefunction - B) Adding new global variables
- C) Restricting access to
tablemethods - D) Blocking
loadstring()
- A) Modifying the
General Lua Customization
- Which command allows you to print the current environment of a Lua function?
- A)
debug.getinfo() - B)
debug.printenv() - C)
getfenv() - D)
env.print()
- A)
- What is the primary benefit of using Lua’s
debug.getlocal()function?- A) Returns local variables of a function
- B) Returns global variables
- C) Modifies local variables
- D) Sets breakpoints in the function
- Which of the following can be done using Lua’s
debug.traceback()function?- A) Trace the call stack of function calls
- B) Output the Lua interpreter’s configuration
- C) Print error messages
- D) List loaded modules
- How can Lua’s
setfenv()function be used to limit global access in a sandboxed environment?- A) By restricting the global environment of functions
- B) By controlling the flow of function execution
- C) By removing access to the
iolibrary - D) By disallowing the use of
require()
- Which security feature in Lua restricts access to certain APIs or system functions in a sandboxed environment?
- A) Lua’s garbage collector
- B) Modified global environment
- C) The debug library
- D) User-defined functions
- What function would you use to safely execute a Lua function in a restricted environment?
- A)
load() - B)
pcall() - C)
dofile() - D)
require()
- A)
- Which Lua function is typically used to simulate a “safe” environment during the execution of untrusted code?
- A)
setmetatable() - B)
loadstring() - C)
setfenv() - D)
debug.sethook()
- A)
- Which of the following is an important consideration when creating a Lua sandbox?
- A) Ensuring the environment is fully isolated from the system
- B) Allowing direct access to system resources for flexibility
- C) Ignoring the performance of sandboxed execution
- D) Disabling debug information completely
- What would happen if you attempt to call the
oslibrary in a properly configured Lua sandbox?- A) It executes normally without restriction
- B) The function will fail due to sandbox restrictions
- C) It will automatically optimize execution
- D) It will request permission from the user
- Which Lua function allows you to manage and alter the global environment in a script?
- A)
setfenv() - B)
getfenv() - C)
load() - D)
dofile()
- A)
Answer Table
| Qno | Answer (Option with the text) |
|---|---|
| 1 | A) collectgarbage() |
| 2 | B) Compile Lua code from a string |
| 3 | C) Customize runtime behavior |
| 4 | D) All of the above |
| 5 | B) It affects the module loading behavior |
| 6 | A) debug.sethook() |
| 7 | C) Monitor function calls, returns, and line changes |
| 8 | B) Line, call, return, and count |
| 9 | A) By logging execution flow and state |
| 10 | C) Hooks do not provide information on function arguments |
| 11 | B) Isolating potentially dangerous code execution |
| 12 | D) setfenv() |
| 13 | A) Modifies the global environment for a function |
| 14 | D) All of the above |
| 15 | A) load() |
| 16 | A) Prevent libraries from being loaded into memory |
| 17 | B) Allowing code to access global resources |
| 18 | A) It loads Lua code from a file, but restricts access to sensitive system resources |
| 19 | D) All of the above |
| 20 | A) Modifying the require function |
| 21 | C) getfenv() |
| 22 | A) Returns local variables of a function |
| 23 | A) Trace the call stack of function calls |
| 24 | A) By restricting the global environment of functions |
| 25 | B) Modified global environment |
| 26 | B) pcall() |
| 27 | C) setfenv() |
| 28 | A) Ensuring the environment is fully isolated from the system |
| 29 | B) The function will fail due to sandbox restrictions |
| 30 | A) setfenv() |