Unsafe in Rust

Use case with sysinfo

by Guillaume Gomez

Who am I?

Rust language reviewer and contributor. Member of:

rustdoc team (team leader)
docs.rs team
tools team

I am a Huawei engineer.

### What is "FFI"? "FFI" stands for "Foreign Function Interface". In short: declaring items from a C library in your Rust code to use them.

### NonNull doesn't solve all issues! * You can still have concurrent access to the data pointed by the pointer. * You still have to free the memory yourself. * You still need to initialize the memory you allocated to the pointer. * You can still have dangling pointers.

### Wrapping pointers is the key

### Unifying different low-level APIs Traits are the key!

### Example with system CPU usage 1. Get diff time 2. Get maximum CPU time 2. Get CPU time

### On Linux Read and parse content from `/proc/stat`... That's it!

### On macOS 1. Use __sysctl__ to get number of processors 2. Get the processors' info with __host_processor_info__

### On Windows Very "opaque". 1. Open connection to "query engine" 2. Create a query (looks like "% Processor time") 3. Translate the query 4. Run the query

### And it was just for one information This is why it's very important to handle it with traits to ensure each platform provides the same information the same way.

### Limitations Unfortunately, not all information can be retrieved on all systems. Components are a good example.

### Going around some limitations Study case: getting a process environment on mac.

Thank you for listening!

More advanced explanations on
< blog.guillaume-gomez.fr >

< guillaume1.gomez@gmail.com >

@GuillaumeGomez

@imperioworld_