Initial checkin from CRI-O repo

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

1 files changed, 325 insertions, 0 deletions

diff --git a/vendor/gopkg.in/fsnotify.v1/inotify.go b/vendor/gopkg.in/fsnotify.v1/inotify.go
new file mode 100644
index 000000000..f3b74c51f
--- /dev/null
+++ b/vendor/gopkg.in/fsnotify.v1/inotify.go
@@ -0,0 +1,325 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux
+
+package fsnotify
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+// Watcher watches a set of files, delivering events to a channel.
+type Watcher struct {
+	Events   chan Event
+	Errors   chan error
+	mu       sync.Mutex // Map access
+	cv       *sync.Cond // sync removing on rm_watch with IN_IGNORE
+	fd       int
+	poller   *fdPoller
+	watches  map[string]*watch // Map of inotify watches (key: path)
+	paths    map[int]string    // Map of watched paths (key: watch descriptor)
+	done     chan struct{}     // Channel for sending a "quit message" to the reader goroutine
+	doneResp chan struct{}     // Channel to respond to Close
+}
+
+// NewWatcher establishes a new watcher with the underlying OS and begins waiting for events.
+func NewWatcher() (*Watcher, error) {
+	// Create inotify fd
+	fd, errno := unix.InotifyInit1(unix.IN_CLOEXEC)
+	if fd == -1 {
+		return nil, errno
+	}
+	// Create epoll
+	poller, err := newFdPoller(fd)
+	if err != nil {
+		unix.Close(fd)
+		return nil, err
+	}
+	w := &Watcher{
+		fd:       fd,
+		poller:   poller,
+		watches:  make(map[string]*watch),
+		paths:    make(map[int]string),
+		Events:   make(chan Event),
+		Errors:   make(chan error),
+		done:     make(chan struct{}),
+		doneResp: make(chan struct{}),
+	}
+	w.cv = sync.NewCond(&w.mu)
+
+	go w.readEvents()
+	return w, nil
+}
+
+func (w *Watcher) isClosed() bool {
+	select {
+	case <-w.done:
+		return true
+	default:
+		return false
+	}
+}
+
+// Close removes all watches and closes the events channel.
+func (w *Watcher) Close() error {
+	if w.isClosed() {
+		return nil
+	}
+
+	// Send 'close' signal to goroutine, and set the Watcher to closed.
+	close(w.done)
+
+	// Wake up goroutine
+	w.poller.wake()
+
+	// Wait for goroutine to close
+	<-w.doneResp
+
+	return nil
+}
+
+// Add starts watching the named file or directory (non-recursively).
+func (w *Watcher) Add(name string) error {
+	name = filepath.Clean(name)
+	if w.isClosed() {
+		return errors.New("inotify instance already closed")
+	}
+
+	const agnosticEvents = unix.IN_MOVED_TO | unix.IN_MOVED_FROM |
+		unix.IN_CREATE | unix.IN_ATTRIB | unix.IN_MODIFY |
+		unix.IN_MOVE_SELF | unix.IN_DELETE | unix.IN_DELETE_SELF
+
+	var flags uint32 = agnosticEvents
+
+	w.mu.Lock()
+	watchEntry, found := w.watches[name]
+	w.mu.Unlock()
+	if found {
+		watchEntry.flags |= flags
+		flags |= unix.IN_MASK_ADD
+	}
+	wd, errno := unix.InotifyAddWatch(w.fd, name, flags)
+	if wd == -1 {
+		return errno
+	}
+
+	w.mu.Lock()
+	w.watches[name] = &watch{wd: uint32(wd), flags: flags}
+	w.paths[wd] = name
+	w.mu.Unlock()
+
+	return nil
+}
+
+// Remove stops watching the named file or directory (non-recursively).
+func (w *Watcher) Remove(name string) error {
+	name = filepath.Clean(name)
+
+	// Fetch the watch.
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	watch, ok := w.watches[name]
+
+	// Remove it from inotify.
+	if !ok {
+		return fmt.Errorf("can't remove non-existent inotify watch for: %s", name)
+	}
+	// inotify_rm_watch will return EINVAL if the file has been deleted;
+	// the inotify will already have been removed.
+	// watches and pathes are deleted in ignoreLinux() implicitly and asynchronously
+	// by calling inotify_rm_watch() below. e.g. readEvents() goroutine receives IN_IGNORE
+	// so that EINVAL means that the wd is being rm_watch()ed or its file removed
+	// by another thread and we have not received IN_IGNORE event.
+	success, errno := unix.InotifyRmWatch(w.fd, watch.wd)
+	if success == -1 {
+		// TODO: Perhaps it's not helpful to return an error here in every case.
+		// the only two possible errors are:
+		// EBADF, which happens when w.fd is not a valid file descriptor of any kind.
+		// EINVAL, which is when fd is not an inotify descriptor or wd is not a valid watch descriptor.
+		// Watch descriptors are invalidated when they are removed explicitly or implicitly;
+		// explicitly by inotify_rm_watch, implicitly when the file they are watching is deleted.
+		return errno
+	}
+
+	// wait until ignoreLinux() deleting maps
+	exists := true
+	for exists {
+		w.cv.Wait()
+		_, exists = w.watches[name]
+	}
+
+	return nil
+}
+
+type watch struct {
+	wd    uint32 // Watch descriptor (as returned by the inotify_add_watch() syscall)
+	flags uint32 // inotify flags of this watch (see inotify(7) for the list of valid flags)
+}
+
+// readEvents reads from the inotify file descriptor, converts the
+// received events into Event objects and sends them via the Events channel
+func (w *Watcher) readEvents() {
+	var (
+		buf   [unix.SizeofInotifyEvent * 4096]byte // Buffer for a maximum of 4096 raw events
+		n     int                                  // Number of bytes read with read()
+		errno error                                // Syscall errno
+		ok    bool                                 // For poller.wait
+	)
+
+	defer close(w.doneResp)
+	defer close(w.Errors)
+	defer close(w.Events)
+	defer unix.Close(w.fd)
+	defer w.poller.close()
+
+	for {
+		// See if we have been closed.
+		if w.isClosed() {
+			return
+		}
+
+		ok, errno = w.poller.wait()
+		if errno != nil {
+			select {
+			case w.Errors <- errno:
+			case <-w.done:
+				return
+			}
+			continue
+		}
+
+		if !ok {
+			continue
+		}
+
+		n, errno = unix.Read(w.fd, buf[:])
+		// If a signal interrupted execution, see if we've been asked to close, and try again.
+		// http://man7.org/linux/man-pages/man7/signal.7.html :
+		// "Before Linux 3.8, reads from an inotify(7) file descriptor were not restartable"
+		if errno == unix.EINTR {
+			continue
+		}
+
+		// unix.Read might have been woken up by Close. If so, we're done.
+		if w.isClosed() {
+			return
+		}
+
+		if n < unix.SizeofInotifyEvent {
+			var err error
+			if n == 0 {
+				// If EOF is received. This should really never happen.
+				err = io.EOF
+			} else if n < 0 {
+				// If an error occurred while reading.
+				err = errno
+			} else {
+				// Read was too short.
+				err = errors.New("notify: short read in readEvents()")
+			}
+			select {
+			case w.Errors <- err:
+			case <-w.done:
+				return
+			}
+			continue
+		}
+
+		var offset uint32
+		// We don't know how many events we just read into the buffer
+		// While the offset points to at least one whole event...
+		for offset <= uint32(n-unix.SizeofInotifyEvent) {
+			// Point "raw" to the event in the buffer
+			raw := (*unix.InotifyEvent)(unsafe.Pointer(&buf[offset]))
+
+			mask := uint32(raw.Mask)
+			nameLen := uint32(raw.Len)
+			// If the event happened to the watched directory or the watched file, the kernel
+			// doesn't append the filename to the event, but we would like to always fill the
+			// the "Name" field with a valid filename. We retrieve the path of the watch from
+			// the "paths" map.
+			w.mu.Lock()
+			name := w.paths[int(raw.Wd)]
+			w.mu.Unlock()
+			if nameLen > 0 {
+				// Point "bytes" at the first byte of the filename
+				bytes := (*[unix.PathMax]byte)(unsafe.Pointer(&buf[offset+unix.SizeofInotifyEvent]))
+				// The filename is padded with NULL bytes. TrimRight() gets rid of those.
+				name += "/" + strings.TrimRight(string(bytes[0:nameLen]), "\000")
+			}
+
+			event := newEvent(name, mask)
+
+			// Send the events that are not ignored on the events channel
+			if !event.ignoreLinux(w, raw.Wd, mask) {
+				select {
+				case w.Events <- event:
+				case <-w.done:
+					return
+				}
+			}
+
+			// Move to the next event in the buffer
+			offset += unix.SizeofInotifyEvent + nameLen
+		}
+	}
+}
+
+// Certain types of events can be "ignored" and not sent over the Events
+// channel. Such as events marked ignore by the kernel, or MODIFY events
+// against files that do not exist.
+func (e *Event) ignoreLinux(w *Watcher, wd int32, mask uint32) bool {
+	// Ignore anything the inotify API says to ignore
+	if mask&unix.IN_IGNORED == unix.IN_IGNORED {
+		w.mu.Lock()
+		defer w.mu.Unlock()
+		name := w.paths[int(wd)]
+		delete(w.paths, int(wd))
+		delete(w.watches, name)
+		w.cv.Broadcast()
+		return true
+	}
+
+	// If the event is not a DELETE or RENAME, the file must exist.
+	// Otherwise the event is ignored.
+	// *Note*: this was put in place because it was seen that a MODIFY
+	// event was sent after the DELETE. This ignores that MODIFY and
+	// assumes a DELETE will come or has come if the file doesn't exist.
+	if !(e.Op&Remove == Remove || e.Op&Rename == Rename) {
+		_, statErr := os.Lstat(e.Name)
+		return os.IsNotExist(statErr)
+	}
+	return false
+}
+
+// newEvent returns an platform-independent Event based on an inotify mask.
+func newEvent(name string, mask uint32) Event {
+	e := Event{Name: name}
+	if mask&unix.IN_CREATE == unix.IN_CREATE || mask&unix.IN_MOVED_TO == unix.IN_MOVED_TO {
+		e.Op |= Create
+	}
+	if mask&unix.IN_DELETE_SELF == unix.IN_DELETE_SELF || mask&unix.IN_DELETE == unix.IN_DELETE {
+		e.Op |= Remove
+	}
+	if mask&unix.IN_MODIFY == unix.IN_MODIFY {
+		e.Op |= Write
+	}
+	if mask&unix.IN_MOVE_SELF == unix.IN_MOVE_SELF || mask&unix.IN_MOVED_FROM == unix.IN_MOVED_FROM {
+		e.Op |= Rename
+	}
+	if mask&unix.IN_ATTRIB == unix.IN_ATTRIB {
+		e.Op |= Chmod
+	}
+	return e
+}