Invalid signal being trapped

Docs > Code Analysis > Static Analysis Rules > Invalid signal being trapped

Metadata

ID: go-best-practices/signal-trapped

Language: Go

Severity: Info

Category: Best Practices

Description

Using signal.Ignore(syscall.SIGKILL) or signal.Reset(os.Kill) to handle the SIGKILL signal is not considered good practice because the SIGKILL signal is designed to be uncatchable and unignorable.

In most operating systems, including Unix-based systems, the SIGKILL signal is a special signal that cannot be caught, ignored, or handled by any process. It is intended as a forceful termination signal that immediately terminates a process without allowing it to perform any cleanup or additional operations.

Therefore, attempting to ignore or reset the SIGKILL signal using signal.Ignore(syscall.SIGKILL) or signal.Reset(os.Kill) will have no effect. The process will still be forcefully terminated when a SIGKILL signal is sent to it.

It is generally not recommended to handle the SIGKILL signal programmatically because it defeats the purpose of the signal itself, which is to guarantee the immediate termination of a process if needed.

Handling other signals, such as SIGINT or SIGTERM, can be useful to gracefully shut down a process and perform necessary cleanup operations before termination. However, SIGKILL signals should not be caught or ignored as they are meant to forcefully terminate processes without any chance of intervention.

In conclusion, it is not good coding practice to use signal.Ignore(syscall.SIGKILL) or signal.Reset(os.Kill) to handle the SIGKILL signal, as it is not catchable or ignorable by design.

Non-Compliant Code Examples

func main () {
    signal.Ignore(os.Signal(signal.SIGKILL))
    signal.Ignore(os.Kill)
    signal.Reset(os.Kill)
    signal.Ignore(syscall.SIGKILL)
    signal.Notify(p, syscall.SIGKILL)
    signal.Notify(p, os.SIGKILL)
}

Compliant Code Examples

func main () {
    signal.Notify(p, os.SIGUSR1)
}