mountrun.go

package main

import (
        "flag"
        "log"
        "os"
        "path/filepath"
        "syscall"
)

func main() {
        var rootFs string
        flag.StringVar(&rootFs, "rootfs", "", "path to rootfs")
        flag.Parse()

        if rootFs == "" {
                log.Fatalf("Rootfs value not specified")
        }

        runDir := filepath.Join(rootFs, "/run")

        if _, err := os.Stat(runDir); os.IsNotExist(err) {
                if err := os.Mkdir("/run", 0755); err != nil {
                        log.Fatalf("Failed to create /run directory: %q", err)
                }
        }

        flags := syscall.MS_NOSUID | syscall.MS_NODEV | syscall.MS_NOEXEC
        if err := syscall.Mount("tmpfs", runDir, "tmpfs", uintptr(flags), "mode=755,size=65000k"); err != nil {
                log.Fatalf("Failed to mount tmpfs at %s: %q", runDir, err)
        }
}