Enforces a path format for storage drivers (#819)

Requires all paths in the inmemory and filesystem drivers to begin with
a slash, and then contain only valid path components (2+ alphanumeric
characters with optional period, hyphen, and underscore separators)
delimited by slashes.

Also updates the storage driver test suites to construct paths of this
format, and causes the suite to abort if files are not cleaned up after
the test run.

storagedriver/inmemory/driver.go

@@ -46,6 +46,10 @@ func New() *Driver {
 
 // GetContent retrieves the content stored at "path" as a []byte.
 func (d *Driver) GetContent(path string) ([]byte, error) {
+	if !storagedriver.PathRegexp.MatchString(path) {
+		return nil, storagedriver.InvalidPathError{Path: path}
+	}
+
 	d.mutex.RLock()
 	defer d.mutex.RUnlock()
 
@@ -60,6 +64,10 @@ func (d *Driver) GetContent(path string) ([]byte, error) {
 
 // PutContent stores the []byte content at a location designated by "path".
 func (d *Driver) PutContent(p string, contents []byte) error {
+	if !storagedriver.PathRegexp.MatchString(p) {
+		return storagedriver.InvalidPathError{Path: p}
+	}
+
 	d.mutex.Lock()
 	defer d.mutex.Unlock()
 
@@ -79,6 +87,10 @@ func (d *Driver) PutContent(p string, contents []byte) error {
 // ReadStream retrieves an io.ReadCloser for the content stored at "path" with a
 // given byte offset.
 func (d *Driver) ReadStream(path string, offset int64) (io.ReadCloser, error) {
+	if !storagedriver.PathRegexp.MatchString(path) {
+		return nil, storagedriver.InvalidPathError{Path: path}
+	}
+
 	d.mutex.RLock()
 	defer d.mutex.RUnlock()
 
@@ -103,6 +115,10 @@ func (d *Driver) ReadStream(path string, offset int64) (io.ReadCloser, error) {
 // WriteStream stores the contents of the provided io.ReadCloser at a location
 // designated by the given path.
 func (d *Driver) WriteStream(path string, offset int64, reader io.Reader) (nn int64, err error) {
+	if !storagedriver.PathRegexp.MatchString(path) {
+		return 0, storagedriver.InvalidPathError{Path: path}
+	}
+
 	d.mutex.Lock()
 	defer d.mutex.Unlock()
 
@@ -135,6 +151,10 @@ func (d *Driver) WriteStream(path string, offset int64, reader io.Reader) (nn in
 
 // Stat returns info about the provided path.
 func (d *Driver) Stat(path string) (storagedriver.FileInfo, error) {
+	if !storagedriver.PathRegexp.MatchString(path) {
+		return nil, storagedriver.InvalidPathError{Path: path}
+	}
+
 	d.mutex.RLock()
 	defer d.mutex.RUnlock()
 
@@ -161,6 +181,10 @@ func (d *Driver) Stat(path string) (storagedriver.FileInfo, error) {
 // List returns a list of the objects that are direct descendants of the given
 // path.
 func (d *Driver) List(path string) ([]string, error) {
+	if !storagedriver.PathRegexp.MatchString(path) && path != "/" {
+		return nil, storagedriver.InvalidPathError{Path: path}
+	}
+
 	normalized := normalize(path)
 
 	found := d.root.find(normalized)
@@ -188,6 +212,12 @@ func (d *Driver) List(path string) ([]string, error) {
 // Move moves an object stored at sourcePath to destPath, removing the original
 // object.
 func (d *Driver) Move(sourcePath string, destPath string) error {
+	if !storagedriver.PathRegexp.MatchString(sourcePath) {
+		return storagedriver.InvalidPathError{Path: sourcePath}
+	} else if !storagedriver.PathRegexp.MatchString(destPath) {
+		return storagedriver.InvalidPathError{Path: destPath}
+	}
+
 	d.mutex.Lock()
 	defer d.mutex.Unlock()
 
@@ -204,6 +234,10 @@ func (d *Driver) Move(sourcePath string, destPath string) error {
 
 // Delete recursively deletes all objects stored at "path" and its subpaths.
 func (d *Driver) Delete(path string) error {
+	if !storagedriver.PathRegexp.MatchString(path) {
+		return storagedriver.InvalidPathError{Path: path}
+	}
+
 	d.mutex.Lock()
 	defer d.mutex.Unlock()