testing unshare CLONE_FS in go routines

test.go

package main

import "fmt"
import "os"

import "time"
import "syscall"
import "runtime"

func thr() {
        runtime.LockOSThread()
        runtime.Gosched()

        err := syscall.Unshare(int(0x00000200)) // CLONE_FS
        if err != nil {
                fmt.Printf("error unsharing CLONE_FS: %v", err)
        }

        dir := fmt.Sprintf("/tmp/go-clone-test/thr-%d-%d", syscall.Getpid(), syscall.Gettid())

        os.MkdirAll(dir, 0755)
        if err != nil {
                fmt.Printf("error mkdir: %v", err)
                return
        }
        err = os.Chdir(dir)
        if err != nil {
                fmt.Printf("error chdir: %v", err)
                return
        }

        cwd, _ := os.Getwd()
        fmt.Printf("in go routine: pid=%d tid=%d cwd=%s\n", syscall.Getpid(), syscall.Gettid(), cwd)
}

func main() {
        cwd, _ := os.Getwd()
        fmt.Printf("BEFORE: in main(): pid=%d tid=%d cwd=%s\n", syscall.Getpid(), syscall.Gettid(), cwd)

        var i int
        for i = 0; i < 3; i++ {
                go thr()
                time.Sleep(10 * time.Millisecond)
        }
        time.Sleep(1000 * time.Millisecond)

        cwd, _ = os.Getwd()
        fmt.Printf("AFTER: in main(): pid=%d tid=%d cwd=%s\n", syscall.Getpid(), syscall.Gettid(), cwd)

        // The output is:
        //
        //BEFORE: in main(): pid=12777 tid=12777 cwd=/home/alban/tmp/test
        //in go routine: pid=12777 tid=12777 cwd=/tmp/go-clone-test/thr-12777-12777
        //in go routine: pid=12777 tid=12779 cwd=/tmp/go-clone-test/thr-12777-12779
        //in go routine: pid=12777 tid=12777 cwd=/tmp/go-clone-test/thr-12777-12777
        //AFTER: in main(): pid=12777 tid=12779 cwd=/tmp/go-clone-test/thr-12777-12779

}