Merge pull request #837 from devlights/add-unix-fork-forkexec-example

Author: devlights

examples/singleapp/unix/forkjoin/03.exec/.gitignore

@@ -0,0 +1 @@
+app

examples/singleapp/unix/forkjoin/03.exec/Taskfile.yml

@@ -0,0 +1,18 @@
+# https://taskfile.dev
+
+version: '3'
+
+vars:
+  APP_NAME: app
+
+tasks:
+  default:
+    cmds:
+      - task: run
+  build:
+    cmds:
+      - go build -o {{.APP_NAME}}{{.exeExt}} .
+  run:
+    deps: [ build ]
+    cmds:
+      - ./{{.APP_NAME}}{{.exeExt}}

examples/singleapp/unix/forkjoin/03.exec/main.go

@@ -0,0 +1,56 @@
+//go:build linux
+
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+func init() {
+	log.SetFlags(0)
+}
+
+func main() {
+	if err := run(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func run() error {
+	var (
+		abs, _ = filepath.Abs(".")
+		bin    = "/bin/ls"
+		args   = []string{bin, "-lh", abs}
+		envs   = []string{"PATH=/usr/bin:/bin"}
+		attr   = syscall.ProcAttr{
+			Dir:   abs,
+			Env:   envs,
+			Files: []uintptr{os.Stdin.Fd(), os.Stdout.Fd(), os.Stderr.Fd()},
+		}
+
+		pid    int
+		err    error
+		status syscall.WaitStatus
+	)
+	if pid, err = syscall.ForkExec(bin, args, &attr); err != nil {
+		return fmt.Errorf("ForkExec() failed: %w", err)
+	}
+
+	log.Printf("[%5d] Child process started", pid)
+
+	if _, err = syscall.Wait4(pid, &status, 0, nil); err != nil {
+		return fmt.Errorf("Wait4() failed: %w", err)
+	}
+
+	if status.Exited() {
+		log.Printf("[%5d] Child process exited with status: %d", pid, status.ExitStatus())
+	} else {
+		log.Printf("[%5d] Child process did not exit normally: %d", pid, status.ExitStatus())
+	}
+
+	return nil
+}