libgocryptfs/tests/test_helpers/mount_unmount.go

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package test_helpers
import (
"fmt"
"io"
"log"
"os"
"os/exec"
"os/signal"
"runtime"
"strings"
"syscall"
"testing"
"time"
)
// gocryptfs may hold up to maxCacheFds open for caching
// Keep in sync with fusefrontend.dirCacheSize
// TODO: How to share this constant without causing an import cycle?!
const maxCacheFds = 20
// Indexed by mountpoint. Initialized in doInit().
var MountInfo map[string]mountInfo
type mountInfo struct {
// PID of the running gocryptfs process. Set by Mount().
Pid int
// List of open FDs of the running gocrypts process. Set by Mount().
Fds []string
}
// Mount CIPHERDIR "c" on PLAINDIR "p"
// Creates "p" if it does not exist.
//
// Contrary to InitFS(), you MUST passt "-extpass=echo test" (or another way for
// getting the master key) explicitly.
func Mount(c string, p string, showOutput bool, extraArgs ...string) error {
args := []string{"-q", "-wpanic", "-nosyslog", "-fg", fmt.Sprintf("-notifypid=%d", os.Getpid())}
args = append(args, extraArgs...)
//args = append(args, "-fusedebug")
//args = append(args, "-d")
args = append(args, c, p)
if _, err := os.Stat(p); err != nil {
err = os.Mkdir(p, 0777)
if err != nil {
return err
}
}
cmd := exec.Command(GocryptfsBinary, args...)
if showOutput {
// The Go test logic waits for our stdout to close, and when we share
// it with the subprocess, it will wait for it to close it as well.
// Use an intermediate pipe so the tests do not hang when unmouting
// fails.
pr, pw, err := os.Pipe()
if err != nil {
return err
}
// We can close the fd after cmd.Run() has executed
defer pw.Close()
cmd.Stderr = pw
cmd.Stdout = pw
go func() {
io.Copy(os.Stdout, pr)
pr.Close()
}()
}
// Two things can happen:
// 1) The mount fails and the process exits
// 2) The mount succeeds and the process sends us USR1
chanExit := make(chan error, 1)
chanUsr1 := make(chan os.Signal, 1)
signal.Notify(chanUsr1, syscall.SIGUSR1)
// Start the process and save the PID
err := cmd.Start()
if err != nil {
return err
}
pid := cmd.Process.Pid
// Wait for exit or usr1
go func() {
chanExit <- cmd.Wait()
}()
select {
case err := <-chanExit:
return err
case <-chanUsr1:
// noop
case <-time.After(2 * time.Second):
log.Panicf("Timeout waiting for process %d", pid)
}
// Save PID and open FDs
MountInfo[p] = mountInfo{pid, ListFds(pid, "")}
return nil
}
// MountOrExit calls Mount() and exits on failure.
//
// Contrary to InitFS(), you MUST passt "-extpass=echo test" (or another way for
// getting the master key) explicitly.
func MountOrExit(c string, p string, extraArgs ...string) {
err := Mount(c, p, true, extraArgs...)
if err != nil {
fmt.Printf("mount failed: %v\n", err)
os.Exit(1)
}
}
// MountOrFatal calls Mount() and calls t.Fatal() on failure.
//
// Contrary to InitFS(), you MUST passt "-extpass=echo test" (or another way for
// getting the master key) explicitly.
func MountOrFatal(t *testing.T, c string, p string, extraArgs ...string) {
err := Mount(c, p, true, extraArgs...)
if err != nil {
t.Fatal(fmt.Errorf("mount failed: %v", err))
}
}
// UnmountPanic tries to umount "dir" and panics on error.
func UnmountPanic(dir string) {
err := UnmountErr(dir)
if err != nil {
fmt.Printf("UnmountPanic: %v. Running lsof %s\n", err, dir)
cmd := exec.Command("lsof", dir)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
cmd.Start()
timer := time.AfterFunc(1*time.Second, func() {
fmt.Printf("timeout!")
cmd.Process.Kill()
})
cmd.Wait()
timer.Stop()
panic("UnmountPanic: unmount failed: " + err.Error())
}
}
// UnmountErr tries to unmount "dir", retrying 10 times, and returns the
// resulting error.
func UnmountErr(dir string) (err error) {
var fdsNow []string
pid := MountInfo[dir].Pid
fds := MountInfo[dir].Fds
if pid <= 0 && runtime.GOOS == "linux" {
// The FD leak check only works on Linux.
fmt.Printf("UnmountErr: %q was not found in MountInfo, cannot check for FD leaks\n", dir)
}
max := 10
// When a new filesystem is mounted, Gnome tries to read files like
// .xdg-volume-info, autorun.inf, .Trash.
// If we try to unmount before Gnome is done, the unmount fails with
// "Device or resource busy", causing spurious test failures.
// Retry a few times to hide that problem.
for i := 1; i <= max; i++ {
if pid > 0 {
for j := 1; j <= max; j++ {
// File close on FUSE is asynchronous, closing a socket
// when testing "-ctlsock" is as well. Wait a little and
// hope that all close commands get through to the gocryptfs
// process.
fdsNow = ListFds(pid, "")
if len(fdsNow) <= len(fds)+maxCacheFds {
break
}
fmt.Printf("UnmountErr: fdsOld=%d fdsNow=%d, retrying\n", len(fds), len(fdsNow))
time.Sleep(10 * time.Millisecond)
fdsNow = ListFds(pid, "")
}
}
cmd := exec.Command(UnmountScript, "-u", dir)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err = cmd.Run()
if err == nil {
if len(fdsNow) > len(fds)+maxCacheFds {
return fmt.Errorf("fd leak in gocryptfs process? pid=%d dir=%q, fds:\nold=%v \nnew=%v\n", pid, dir, fds, fdsNow)
}
return nil
}
code := ExtractCmdExitCode(err)
fmt.Printf("UnmountErr: got exit code %d, retrying (%d/%d)\n", code, i, max)
time.Sleep(100 * time.Millisecond)
}
return err
}
// ListFds lists the open file descriptors for process "pid". Pass pid=0 for
// ourselves. Pass a prefix to ignore all paths that do not start with "prefix".
func ListFds(pid int, prefix string) []string {
// We need /proc to get the list of fds for other processes. Only exists
// on Linux.
if runtime.GOOS != "linux" && pid > 0 {
return nil
}
// Both Linux and MacOS have /dev/fd
dir := "/dev/fd"
if pid > 0 {
dir = fmt.Sprintf("/proc/%d/fd", pid)
}
f, err := os.Open(dir)
if err != nil {
fmt.Printf("ListFds: %v\n", err)
return nil
}
defer f.Close()
// Note: Readdirnames filters "." and ".."
names, err := f.Readdirnames(0)
if err != nil {
log.Panic(err)
}
var out []string
var filtered []string
for _, n := range names {
fdPath := dir + "/" + n
fi, err := os.Lstat(fdPath)
if err != nil {
// fd was closed in the meantime
continue
}
if fi.Mode()&0400 > 0 {
n += "r"
}
if fi.Mode()&0200 > 0 {
n += "w"
}
target, err := os.Readlink(fdPath)
if err != nil {
// fd was closed in the meantime
continue
}
if strings.HasPrefix(target, "pipe:") || strings.HasPrefix(target, "anon_inode:[eventpoll]") {
// The Go runtime creates pipes on demand for splice(), which
// creates spurious test failures. Ignore all pipes.
// Also get rid of the "eventpoll" fd that is always there and not
// interesting.
filtered = append(filtered, target)
continue
}
if prefix != "" && !strings.HasPrefix(target, prefix) {
filtered = append(filtered, target)
continue
}
out = append(out, n+"="+target)
}
out = append(out, fmt.Sprintf("(filtered: %s)", strings.Join(filtered, ", ")))
return out
}