iOS Dynamic Interpose PoC DYLIB
I had a problem I needed to solve which eventually lead me down a road to developing this PoC DYLIB that effectively replaces the implementation of a given C/C++ function at runtime.
Sort of like objective-c method swizzling, but for C/C++!
dynamic library code → ./main.c
sample target binary code → ./target.c
You can inject the dylib however you like, but for simplicity, you could use DYLD_INSERT_LIBRARIES to load the dylib at launch:
DYLD_INSERT_LIBRARIES=/interpose.dylib ./target
For injecting the dylib at runtime, you could try substrate or similar.