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Kevin Thomas
50 lines
2.2 KiB
Markdown
50 lines
2.2 KiB
Markdown
# Embedded Systems Reverse Engineering
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[Repository](https://github.com/mytechnotalent/Embedded-Hacking)
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## Week 1
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Introduction and Overview of Embedded Reverse Engineering: Ethics, Scoping, and Basic Concepts
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### Non-Credit Practice Exercise 1 Solution: Explore in Ghidra
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#### Answers
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##### Question 1: What does the function return?
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`stdio_init_all()` returns `_bool` (displayed as `void` in some Ghidra versions). The function signature shows `_bool stdio_init_all(void)`.
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##### Question 2: What parameters does it take?
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**None** - the function signature shows `(void)` in parentheses, meaning zero parameters.
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##### Question 3: What functions does it call?
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`stdio_init_all()` calls initialization functions for:
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- **USB CDC** initialization (USB serial communication)
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- **UART** initialization (serial pin communication)
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These set up the standard I/O subsystem so that `printf()` can output data.
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##### Question 4: What's the purpose?
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`stdio_init_all()` initializes **Standard Input/Output** for the Pico 2:
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- **std** = Standard
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- **io** = Input/Output
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It sets up both USB CDC and UART communication channels, which allows `printf()` to send output through the serial connection.
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##### Expected Output
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```
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stdio_init_all() returns: void (_bool)
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It takes 0 parameters
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It calls the following functions: USB CDC init, UART init
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Based on these calls, I believe it initializes: Standard I/O for USB and UART serial communication
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```
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#### Reflection Answers
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1. **Why would we need to initialize standard I/O before using `printf()`?**
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Without initialization, there is no communication channel configured. `printf()` needs a destination (USB or UART) to send its output. Without `stdio_init_all()`, output has nowhere to go.
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2. **Can you find other functions in the Symbol Tree that might be related to I/O?**
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Yes - functions like `stdio_usb_init`, `stdio_uart_init`, `__wrap_puts`, and other I/O-related functions appear in the Symbol Tree.
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3. **How does this function support the `printf("hello, world\r\n")` call in main?**
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It configures the USB and UART hardware so that when `printf()` (optimized to `__wrap_puts`) executes, the characters are transmitted over the serial connection to the host computer.
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