fork

Library for creating a new process detached from the controling terminal (daemon).

Why?

• Minimal library to daemonize, fork, double-fork a process.
• daemon(3) has been deprecated in MacOSX 10.5, by using fork and setsid syscalls, new methods can be created to achieve the same goal.

Example:

Create a new test project:

$ cargo new --bin fork

To install cargo use: curl https://sh.rustup.rs -sSf | sh

Edit fork/Cargo.toml and add to [dependecies]:

fork = "0.1"

Add the following code to fork/main.rs

```rs use fork::{daemon, Fork}; use std::process::Command;

fn main() { if let Ok(Fork::Child) = daemon(false, false) { Command::new("sleep") .arg("300") .output() .expect("failed to execute process"); } } ```

If using daemon(false, false),it will chdir to / and close the standard input, standard output, and standard error file descriptors.

Test running:

$ cargo run

Use ps to check the process, for example:

$ ps -axo ppid,pid,pgid,sess,tty,tpgid,stat,uid,%mem,%cpu,command, | egrep "fork|sleep|PID"

egrep is used to show the ps headers

Output should be something like:

pre PPID PID PGID SESS TTY TPGID STAT UID %MEM %CPU COMMAND 1 48738 48737 0 ?? 0 S 501 0.0 0.0 target/debug/fork 48738 48753 48737 0 ?? 0 S 501 0.0 0.0 sleep 300

• PPID == 1 that's the parent process
• TTY = ?? no controlling terminal

• new PGID = 48737

  1 - root (init/launchd) -- 48738 fork PGID - 48737 --- 48753 sleep PGID - 48737