feat: Add spawning processes

.gitignore

@@ -0,0 +1 @@
+init

main.go

@@ -7,12 +7,52 @@ import (
 
 func main() {
 	inittab := DefaultInitTab
-	if file, err := os.OpenFile("/etc/inittab", os.O_RDONLY, 0644); err != nil {
+	if file, err := os.OpenFile("/etc/inittab", os.O_RDONLY, 0644); err == nil {
 		inittab = ParseInitTab(file)
 		err := file.Close()
 		if err != nil {
-			fmt.Println("close inittab:", err)
+			fmt.Printf("error closing inittab: %s\n", err)
+		}
+	} else {
+		fmt.Printf("error reading inittab: %s\n", err)
+	}
+
+	for _, entry := range inittab.Entries(SysInit) {
+		err := Exec(entry)
+		if err != nil {
+			fmt.Printf("error running sysinit \"%s\": %s\n", entry.Process, err)
 		}
 	}
 
+	for _, entry := range inittab.Entries(Wait) {
+		err := Exec(entry)
+		if err != nil {
+			fmt.Printf("error running wait \"%s\": %s\n", entry.Process, err)
+		}
+	}
+
+	for _, entry := range inittab.Entries(Once) {
+		_, err := Spawn(entry)
+		if err != nil {
+			fmt.Printf("error running once \"%s\": %s\n", entry.Process, err)
+		}
+	}
+
+	// TODO implement AskFirst handling
+
+	for _, entry := range inittab.Entries(Respawn) {
+		go func(entry InitTabEntry) {
+			for {
+				err := Exec(entry)
+				if err != nil {
+					fmt.Printf("error running respawn \"%s\": %s\n", entry.Process, err)
+					break
+				}
+			}
+		}(entry)
+	}
+
+	// TODO implement Shutdown, Restart and CtrlAltDel handling
+
+	select {}
 }

process.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+func Spawn(entry InitTabEntry) (*exec.Cmd, error) {
+	cmdline := strings.Split(entry.Process, " ")
+	cmd := exec.Command(cmdline[0], cmdline[1:]...)
+
+	// TODO: add stdio handling
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	err := cmd.Start()
+	if err != nil {
+		return nil, err
+	}
+
+	return cmd, nil
+}
+
+func Exec(entry InitTabEntry) error {
+	cmd, err := Spawn(entry)
+	if err != nil {
+		return fmt.Errorf("spawn: %w", err)
+	}
+
+	err = cmd.Wait()
+	if err != nil {
+		return fmt.Errorf("wait: %w", err)
+	}
+
+	return nil
+}