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Intercept malloc and free with LD_PRELOAD

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Implement a Simple Debugger with ptraceNext

Language

Compiler

2.0s Limit 256MB

Implementation

Write a C program that documents and demonstrates how LD_PRELOAD can intercept malloc and free calls to add logging.

Requirements:

Print the LD_PRELOAD environment variable usage
Show the interceptor code that wraps malloc and free
Explain dlsym(RTLD_NEXT, ...) for calling the original function
Output must mention LD_PRELOAD, malloc, and intercept
Demonstrate logging of allocation size and address

Why This Matters

Memory-debugging tools like Electric Fence, and lightweight leak-detection scripts, are built entirely on the LD_PRELOAD + dlsym(RTLD_NEXT, ...) pattern you write here, letting engineers instrument a program's malloc/free calls with zero source changes. The same mechanism is also a classic Linux rootkit persistence and syscall-hooking technique, which is why security-hardened systems restrict or audit LD_PRELOAD usage.

Hints

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Validation Suite

main.c

Workspace 1.0