Mastering Signal Handling in Rust

Understanding Signals and Signal Handling

Signals are software interrupts sent to a process by the operating system or another process to notify it of an event. When a process receives a signal, it can take a specific action depending on the type of signal.

Types of Signals

• SIGINT: Interrupt signal, triggered when the user presses Control+C
• SIGTERM: Termination signal, triggered when the operating system wants to terminate the process
• SIGKILL: Kill signal, triggered when the operating system wants to forcibly terminate the process

Signal Dispositions

Signal disposition refers to the default action that the OS takes when a process receives a particular signal. The three possible signal dispositions are:

1. Terminate: The process is terminated immediately without any chance to clean up or save state
2. Ignore: The process does nothing in response to the signal
3. Catch: The process runs a user-defined signal handler function to handle the signal

Handling Signals in Rust

Rust provides several libraries that enable developers to handle signals with ease. In this article, we’ll use the tokio crate to handle signals.

Example: Handling SIGINT with Tokio

First, create a Rust project with Cargo and install tokio by running the following command:

cargo add tokio

Then, update the Cargo.toml file to include the tokio dependency:

[dependencies]
tokio = { version = "1", features = ["full"] }

Next, create a new file called main.rs and add the following code:

use tokio::signal;

#[tokio::main]
async fn main() {
    let mut sigint = signal::ctrl_c();
    println!("Press Control+C to trigger SIGINT");
    sigint.recv().await;
    println!("SIGINT received!");
}

Run the code using cargo run and press Control+C to trigger the SIGINT signal.

Signal Masking in Rust

Signal masking is the process of temporarily blocking the delivery of certain signals to a process or a thread. When masked, a signal