add basic support of the system calls 'fork' and 'spawn_process'

Cargo.toml

@@ -7,8 +7,13 @@ members = [
     "benches/mutex",
     "benches/startup",
     "benches/multithreaded",
+    "benches/getpid",
     "examples/axum",
     "examples/demo",
+    "examples/fork",
+    "examples/pipe",
+    "examples/true",
+    "examples/false",
     "examples/fuse_test",
     "examples/hello_world",
     "examples/httpd",
@@ -17,6 +22,7 @@ members = [
     "examples/mioudp",
     "examples/polling",
     "examples/rftrace-example",
+    "examples/spawn",
     "examples/stdin",
     "examples/testtcp",
     "examples/testudp",

benches/getpid/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "getpid"
+authors = ["Stefan Lankes <slankes@eonerc.rwth-aachen.de>"]
+edition = "2021"
+
+[dependencies]
+hermit-abi = { path = "../../hermit-abi" }
+
+[target.'cfg(target_os = "hermit")'.dependencies]
+hermit = { path = "../../hermit", default-features = false }
+
+[features]
+default = ["hermit/acpi", "hermit/pci"]

benches/getpid/src/main.rs

@@ -0,0 +1,28 @@
+use std::hint::black_box;
+use std::time::{Duration, Instant};
+
+#[cfg(target_os = "hermit")]
+use hermit as _;
+use hermit_abi::getpid;
+
+fn getpid_bench(count: usize) -> Duration {
+	let start = Instant::now();
+	for _ in 0..count {
+		let _pid = black_box(unsafe { getpid() });
+	}
+	start.elapsed()
+}
+
+fn main() {
+	println!("Determine overhead of getpid...");
+
+	// warmup cache
+	let _ = getpid_bench(2);
+
+	let count = 10_0000_0000;
+	let result = black_box(getpid_bench(count));
+
+	println!("Number of iterations: {count}");
+	println!("Total time: {result:?}");
+	println!("Time per getpid: {:?}", result / count.try_into().unwrap());
+}

examples/false/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "false"
+authors = ["Stefan Lankes <slankes@eonerc.rwth-aachen.de>"]
+edition = "2021"
+
+[target.'cfg(target_os = "hermit")'.dependencies]
+hermit = { path = "../../hermit", default-features = false }
+
+[features]
+default = ["hermit/acpi", "hermit/pci"]

examples/false/src/main.rs

@@ -0,0 +1,6 @@
+#[cfg(target_os = "hermit")]
+use hermit as _;
+
+fn main() {
+	std::process::exit(1);
+}

examples/fork/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "fork"
+authors = ["Stefan Lankes <slankes@eonerc.rwth-aachen.de>"]
+edition = "2021"
+
+[dependencies]
+hermit-abi = { path = "../../hermit-abi" }
+
+[target.'cfg(target_os = "hermit")'.dependencies]
+hermit = { path = "../../hermit", default-features = false }
+
+[features]
+default = ["hermit/acpi", "hermit/pci"]

examples/fork/src/main.rs

@@ -0,0 +1,75 @@
+use std::time::{Duration, Instant};
+
+#[cfg(target_os = "hermit")]
+use hermit as _;
+use hermit_abi::{exec, fork, getpid, waitpid, Pid};
+
+fn fork_bench(count: usize) -> Duration {
+	let mut pids = vec![Pid::default(); count]; // Pre-allocate with zeros
+	let app = c"/bin/true";
+
+	let start = Instant::now();
+	for pid in pids.iter_mut().take(count) {
+		*pid = unsafe { fork() };
+
+		if *pid == 0 {
+			//std::process::exit(0);
+			unsafe {
+				let _ = exec(app.as_ptr(), std::ptr::null(), std::ptr::null());
+			}
+		}
+	}
+
+	for pid in &pids {
+		unsafe {
+			waitpid(*pid);
+		}
+	}
+
+	start.elapsed()
+}
+
+fn main() {
+	println!("Try to fork a process...");
+
+	let pid = unsafe { fork() };
+	if pid == 0 {
+		println!("Hello from child process with id {}!", unsafe { getpid() });
+
+		let app = c"/bin/hello_world";
+		// Pass an argument vector and an environment to the new
+		// process image; both arrays are NULL-terminated.
+		let argv = [app.as_ptr(), c"--from-exec".as_ptr(), std::ptr::null()];
+		let envp = [c"GREETING=Hello from exec!".as_ptr(), std::ptr::null()];
+		unsafe {
+			let _ = exec(app.as_ptr(), argv.as_ptr(), envp.as_ptr());
+		}
+
+		println!("ERROR: Exec failed!!!");
+	} else if pid > 0 {
+		println!(
+			"Hello from parent process with id {}! Child has the id {}!",
+			unsafe { getpid() },
+			pid
+		);
+
+		unsafe {
+			waitpid(pid);
+		}
+
+		println!("Measure overhead of the system call fork.");
+
+		// warmup cache
+		let _ = fork_bench(2);
+
+		for i in 0..14 {
+			let count = 1 << i;
+			let result = fork_bench(count);
+			println!("Time to fork/join {count} processes: {result:?}");
+		}
+	} else {
+		println!("Unable to fork a process!");
+	}
+
+	println!("Leave program");
+}

examples/hello_world/src/main.rs

@@ -3,4 +3,11 @@ use hermit as _;
 
 fn main() {
 	println!("Hello, world!");
+
+	for (i, arg) in std::env::args().enumerate() {
+		println!("arg[{i}]: {arg}");
+	}
+	for (key, value) in std::env::vars() {
+		println!("env: {key}={value}");
+	}
 }

examples/pipe/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "pipe"
+authors = ["Stefan Lankes <slankes@eonerc.rwth-aachen.de>"]
+edition = "2021"
+
+[dependencies]
+hermit-abi = { path = "../../hermit-abi" }
+
+[target.'cfg(target_os = "hermit")'.dependencies]
+hermit = { path = "../../hermit", default-features = false }
+
+[features]
+default = ["hermit/acpi", "hermit/pci"]