Tweak

cmds/cpu/cpu.go

@@ -31,7 +31,8 @@ const defaultPort = "17010"
 
 var (
 	defaultKeyFile = filepath.Join(os.Getenv("HOME"), ".ssh/cpu_rsa")
-	// For the ssh server part
+	// cpuns might not be in the limited search path of sshd. Allow users to set it.
+	cpuns       = flag.String("cpuns", "cpuns", "command to run to build cpu namespace")
 	debug       = flag.Bool("d", false, "enable debug prints")
 	dbg9p       = flag.Bool("dbg9p", false, "show 9p io")
 	dump        = flag.Bool("dump", false, "Dump copious output, including a 9p trace, to a temp file at exit")
@@ -49,7 +50,7 @@ var (
 	srvnfs   = flag.Bool("nfs", false, "start nfs")
 	cpioRoot = flag.String("cpio", "", "cpio initrd")
 
-	ssh = flag.Bool("ssh", false, "ssh only, no internal 9p, nfs, or mounts")
+	ssh  = flag.Bool("ssh", false, "ssh only, no internal 9p, nfs, or mounts")
 	sshd = flag.Bool("sshd", false, "server is sshd, not cpud")
 
 	// v allows debug printing.
@@ -153,7 +154,7 @@ func newCPU(host string, args ...string) (retErr error) {
 	if *sshd && *srvnfs {
 		env := append(os.Environ(), "CPU_PWD="+os.Getenv("PWD"))
 		envargs := "-env=" + strings.Join(env, "\n")
-		args = append([]string{"cpuns", envargs}, args...)
+		args = append([]string{*cpuns, envargs}, args...)
 	}
 	c := client.Command(host, args...)
 	defer func() {
@@ -215,9 +216,9 @@ func newCPU(host string, args ...string) (retErr error) {
 			log.Printf("nfs: %v", err)
 			// wg.Done()
 		}()
-		verbose("nfsmount %q fstab %q join %q", nfsmount, fstab, client.JoinFSTab(nfsmount, fstab))
-		fstab = client.JoinFSTab(nfsmount, fstab)
-		c.Env = append(c.Env, "CPU_FSTAB="+fstab, "LC_GLENDA_CPU_FSTAB="+fstab)
+		jfstab := client.JoinFSTab(nfsmount, fstab)
+		c.Env = append(c.Env, "CPU_FSTAB="+jfstab, "LC_GLENDA_CPU_FSTAB="+jfstab)
+		verbose("nfsmount %q fstab %q join %q env %q", nfsmount, fstab, jfstab, c.Env)
 	}
 
 	go func() {

cmds/cpuns/main_linux.go

@@ -65,34 +65,33 @@ func checkprivate() error {
 // sudo will get us into a root process, with correct environment
 // set up.
 func sudo(env string, args ...string) {
-	log.Printf("sudo: os.Env %v\nenv %v\nargs %v", os.Environ(), env, args)
 	n, err := os.Executable()
 	if err != nil {
 		log.Fatal(err)
 	}
 
-	v("Executable: %q", n)
+	verbose("Executable: %q", n)
 	// sshd filters most environment variables save LC_*.
 	// sudo strips most LC_* variables.
 	// the cpu command sets LC_GLENDA_CPU_FSTAB to the fstab;
 	// we need to transform it here.
 
-	c := exec.Command("sudo", append([]string{"-E", n, "-env=" + env}, args...)...)
-	v("exec.Cmd args %q", c.Args)
+	c := exec.Command("sudo", append([]string{"--preserve-env=CPU_FSTAB", n, "-env=" + env}, args...)...)
+	verbose("exec.Cmd args %q", c.Args)
 
 	// Find the environment variable, and transform it.
 	// sudo seems to strip many LC_* variables.
 	fstab, ok := os.LookupEnv("LC_GLENDA_CPU_FSTAB")
-	v("fstab set? %v value %q", ok, fstab)
+	verbose("fstab set? %v value %q", ok, fstab)
 	if ok {
 		c.Env = append(c.Env, "CPU_FSTAB="+fstab)
-		v("extended c.Env: %v", c.Env)
+		verbose("extended c.Env: %v", c.Env)
 	}
 	if s := strings.Split(env, "\n"); len(s) > 0 {
 		c.Env = append(c.Env, s...)
 	}
 	c.Stdin, c.Stdout, c.Stderr = os.Stdin, os.Stdout, os.Stderr
-	v("Run %q", c)
+	verbose("Run %q", c)
 
 	// The return is carefully done here to avoid the caller
 	// making a mistake and fork-bomb.
@@ -107,7 +106,6 @@ func sudo(env string, args ...string) {
 // Be very careful in modifying this; it is designed to be
 // simple and avoid fork bombs.
 func unshare(env string, args ...string) {
-	log.Printf("unshare: os.Env %v\nenv %v\n args %v", os.Environ(), env, args)
 	n, err := os.Executable()
 	if err != nil {
 		log.Fatal(err)
@@ -119,21 +117,24 @@ func unshare(env string, args ...string) {
 	// we need to transform it here.
 	// Since we can get here direct from sshd, not sudo,
 	// we have to this twice.
-	v("Executable: %q", n)
+	verbose("Executable: %q", n)
 	c := exec.Command(n, args...)
-	v("exec.Cmd args %q", c.Args)
+	verbose("exec.Cmd args %q", c.Args)
+
+	c.Env = os.Environ()
+	if s := strings.Split(env, "\n"); len(s) > 0 {
+		c.Env = append(c.Env, s...)
+	}
 
 	fstab, ok := os.LookupEnv("LC_GLENDA_CPU_FSTAB")
-	v("fstab set? %v value %q", ok, fstab)
+	verbose("fstab set? %v value %q", ok, fstab)
 	if ok {
 		c.Env = append(c.Env, "CPU_FSTAB="+fstab)
-		v("extended c.Env: %v", c.Env)
-		if s := strings.Split(env, "\n"); len(s) > 0 {
-			c.Env = append(c.Env, s...)
-		}
+		verbose("extended c.Env: %v", c.Env)
 	}
+
 	c.Stdin, c.Stdout, c.Stderr, c.Dir = os.Stdin, os.Stdout, os.Stderr, os.Getenv("PWD")
-	v("Run %q", c)
+	verbose("Run %q", c)
 
 	c.SysProcAttr = &syscall.SysProcAttr{Unshareflags: syscall.CLONE_NEWNS}
 	// The return is carefully done here to avoid the caller
@@ -154,21 +155,23 @@ func main() {
 	flag.Parse()
 	if *debug {
 		v = log.Printf
-		verbose("cpuns: os.Args %q", os.Args)
 		session.SetVerbose(v)
+		verbose("cpuns: os.Args %q env %q", os.Args, os.Environ())
 	}
 	args := flag.Args()
-	v("LC_GLENDA_CPU_FSTAB %s", os.Getenv("LC_GLENDA_CPU_FSTAB"))
-	v("CPU_FSTAB %s", os.Getenv("CPU_FSTAB"))
+	verbose("LC_GLENDA_CPU_FSTAB %s", os.Getenv("LC_GLENDA_CPU_FSTAB"))
+	verbose("CPU_FSTAB %s", os.Getenv("CPU_FSTAB"))
+	verbose("env\n\n%q\n\n", *env)
 	if os.Getuid() != 0 {
+		verbose("sudo %q %q", *env, args)
 		sudo(*env, args...)
 	}
 
 	if err := checkprivate(); err != nil {
+		verbose("unshare %q %q", *env, args)
 		unshare(*env, args...)
 	}
 
-	log.Printf("mount and run: os.Env %v\n*env %v\n args %v", os.Environ(), *env, args)
 	shell := "/bin/sh"
 	if len(args) == 0 {
 		sh, ok := os.LookupEnv("SHELL")
@@ -191,8 +194,8 @@ func main() {
 	}
 
 	// the default value of uid, gid is 0
-	uid := uint32(os.Getuid())
-	gid := uint32(os.Getgid())
+	uid := uint32(syscall.Getuid())
+	gid := uint32(syscall.Getgid())
 	if u, ok := os.LookupEnv("SUDO_UID"); ok {
 		i, err := strconv.ParseUint(u, 0, 32)
 		if err != nil {
@@ -209,10 +212,10 @@ func main() {
 	}
 
 	c := s.Command()
+	c.Env = os.Environ()
 	if s := strings.Split(*env, "\n"); len(s) > 0 {
 		c.Env = append(c.Env, s...)
 	}
-	verbose("cpuns: Command is %q, with args %q", c, args)
 	pwd := os.Getenv("CPU_PWD")
 	if _, err := os.Stat(pwd); err != nil {
 		log.Printf("%v:setting pwd to /", err)
@@ -221,6 +224,7 @@ func main() {
 	c.Stdin, c.Stdout, c.Stderr, c.Dir = s.Stdin, s.Stdout, s.Stderr, pwd
 	c.SysProcAttr = &syscall.SysProcAttr{}
 	c.SysProcAttr.Credential = &syscall.Credential{Uid: uint32(uid), Gid: uint32(gid)}
+	verbose("Run %q %q %q", c, c.Args, c.Env)
 	if err := c.Run(); err != nil {
 		log.Fatalf("Run %v returns %v", c, err)
 	}