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Parse and Load an ELF Binary from Disk

hard6/8

Get Memory Map via BIOS INT 0x15 E820 Implement a Multiboot-Compliant Bootloader Header

Language

Compiler

2.0s Limit 256MB

Submit and pass all tests to enable saving to GitHub.

Implementation

Implement an ELF binary parser and loader in boot sector code.

Requirements:

Define ELF32 header and program header structures
Read ELF header from disk (simulated with embedded data)
Verify magic bytes (0x7F, 'E', 'L', 'F')
Parse program headers
For each PT_LOAD segment, print offset, physical address, file size, memory size
Calculate total memory required
Print entry point address
Show segment permissions (read/write/execute)
Handle errors for invalid ELF files
Demonstrate with a sample ELF structure

Test:

Show ELF magic verified
Show entry point printed
Show program headers parsed
Show load addresses and sizes
Show error for invalid magic

Why This Matters

This is precisely how the Linux kernel's own bzImage decompression stub and hobby kernels like xv6-derivatives interpret PT_LOAD program headers to place segments at p_paddr before jumping to e_entry. Getting the p_memsz vs p_filesz distinction wrong (forgetting to zero the BSS gap) is a textbook bug that leaves global variables containing stale disk bytes instead of zero.

Hints

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Validation Suite

main.c

Workspace 1.0

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