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A container in less than 60 lines of Go
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package main | |
import ( | |
"fmt" | |
"os" | |
"os/exec" | |
"syscall" | |
) | |
func main() { | |
switch os.Args[1] { | |
case "run": | |
parent() | |
case "child": | |
child() | |
default: | |
panic("wat should I do") | |
} | |
} | |
func parent() { | |
cmd := exec.Command("/proc/self/exe", append([]string{"child"}, os.Args[2:]...)...) | |
cmd.SysProcAttr = &syscall.SysProcAttr{ | |
Cloneflags: syscall.CLONE_NEWUTS | syscall.CLONE_NEWPID | syscall.CLONE_NEWNS, | |
} | |
cmd.Stdin = os.Stdin | |
cmd.Stdout = os.Stdout | |
cmd.Stderr = os.Stderr | |
if err := cmd.Run(); err != nil { | |
fmt.Println("ERROR", err) | |
os.Exit(1) | |
} | |
} | |
func child() { | |
must(syscall.Mount("rootfs", "rootfs", "", syscall.MS_BIND, "")) | |
must(os.MkdirAll("rootfs/oldrootfs", 0700)) | |
must(syscall.PivotRoot("rootfs", "rootfs/oldrootfs")) | |
must(os.Chdir("/")) | |
cmd := exec.Command(os.Args[2], os.Args[3:]...) | |
cmd.Stdin = os.Stdin | |
cmd.Stdout = os.Stdout | |
cmd.Stderr = os.Stderr | |
if err := cmd.Run(); err != nil { | |
fmt.Println("ERROR", err) | |
os.Exit(1) | |
} | |
} | |
func must(err error) { | |
if err != nil { | |
panic(err) | |
} | |
} |
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