### RTLD Loader Logic (C)

Source: https://github.com/replit/replit_rtld_loader/blob/main/README.md

Illustrates the core logic of the RTLD loader, specifically how it uses the `la_objsearch` hook from the rtld-audit API. It intercepts library loading failures (when `flag` is `LA_SER_DEFAULT`) and searches `REPLIT_LD_LIBRARY_PATH` for the requested library.

```C
/* Inside the rtld_loader.so library */

/* Function called by the dynamic linker */
unsigned int la_objsearch(const char *name, unsigned int flags, unsigned int version) {
    if (flags == LA_SER_DEFAULT) {
        /* System loader failed, try REPLIT_LD_LIBRARY_PATH */
        /* ... search logic ... */
        /* If found, return full path */
        /* return "/path/to/found/library.so"; */
    }
    /* Fallback to default behavior */
    return 0;
}
```

--------------------------------

### Activating RTLD Loader

Source: https://github.com/replit/replit_rtld_loader/blob/main/README.md

Demonstrates how to activate the Replit RTLD Loader using the LD_AUDIT environment variable when running a Python program. This is the primary method to enable the loader's functionality.

```Shell
LD_AUDIT=rtld_loader.so python main.py
```

--------------------------------

### RTLD Loader Logging Levels

Source: https://github.com/replit/replit_rtld_loader/blob/main/README.md

Explains how to control the verbosity of the Replit RTLD Loader's output using the REPLIT_RTLD_LOG_LEVEL environment variable. Different levels provide varying amounts of diagnostic information.

```Shell
REPLIT_RTLD_LOG_LEVEL=0
REPLIT_RTLD_LOG_LEVEL=1
REPLIT_RTLD_LOG_LEVEL=2
REPLIT_RTLD_LOG_LEVEL=3
```

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