Merge pull request #1276 from ipfs/debug/perm-fail

trying to debug permissions failure

repo/fsrepo/lock/lock.go

 package lock
 
 import (
+	"fmt"
 	"io"
 	"os"
 	"path"
+	"strings"
+	"syscall"
 
 	lock "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/camlistore/lock"
 	"github.com/ipfs/go-ipfs/util"
@@ -13,6 +16,10 @@ import (
 // TODO rename repo lock and hide name
 const LockFile = "repo.lock"
 
+func errPerm(path string) error {
+	return fmt.Errorf("failed to take lock at %s: permission denied", path)
+}
+
 func Lock(confdir string) (io.Closer, error) {
 	c, err := lock.Lock(path.Join(confdir, LockFile))
 	return c, err
@@ -23,12 +30,28 @@ func Locked(confdir string) (bool, error) {
 		return false, nil
 	}
 	if lk, err := Lock(confdir); err != nil {
+		// EAGAIN == someone else has the lock
+		if err == syscall.EAGAIN {
+			return true, nil
+		}
+
+		// lock fails on permissions error
 		if os.IsPermission(err) {
-			return false, err
+			return false, errPerm(confdir)
 		}
-		return true, nil
+		if isLockCreatePermFail(err) {
+			return false, errPerm(confdir)
+		}
+
+		// otherwise, we cant guarantee anything, error out
+		return false, err
 	} else {
 		lk.Close()
 		return false, nil
 	}
 }
+
+func isLockCreatePermFail(err error) bool {
+	s := err.Error()
+	return strings.Contains(s, "Lock Create of") && strings.Contains(s, "permission denied")
+}

test/sharness/t0020-init.sh

@@ -20,7 +20,7 @@ test_expect_success "ipfs init fails" '
 '
 
 test_expect_success "ipfs init output looks good" '
-	echo "Error: open $IPFS_PATH/repo.lock: permission denied" > init_fail_exp &&
+	echo "Error: failed to take lock at $IPFS_PATH: permission denied" > init_fail_exp &&
 	test_cmp init_fail_out init_fail_exp
 '