1 ;; Copyright (C) 2009 Olof-Joachim Frahm
3 ;; This program is free software; you can redistribute it and/or modify it
4 ;; under the terms of the GNU General Public License as published by the
5 ;; Free Software Foundation; either version 3 of the License, or (at your
6 ;; option) any later version.
8 ;; This program is distributed in the hope that it will be useful, but
9 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
10 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
11 ;; Public License for more details.
13 ;; You should have received a copy of the GNU General Public License along
14 ;; with this program; if not, see <http://www.gnu.org/licenses/>.
16 (in-package #:cl-notify)
18 (defbitfield (inotify-flag :uint32)
22 (:close-write #.in-close-write)
23 (:close-nowrite #.in-close-nowrite)
26 (:moved-from #.in-moved-from)
27 (:moved-to #.in-moved-to)
31 (:delete-self #.in-delete-self)
32 (:move-self #.in-move-self)
33 (:unmount #.in-unmount)
34 (:q-overflow #.in-q-overflow)
35 (:ignored #.in-ignored)
36 (:onlydir #.in-onlydir)
37 (:dont-follow #.in-dont-follow)
38 (:mask-add #.in-mask-add)
40 (:oneshot #.in-oneshot)
41 (:all-events #.in-all-events))
43 (deftype inotify-add/read-flag ()
44 "Shared valid flags for the WATCH and READ-EVENT functions."
47 :close-write :close-nowrite :close
48 :create :delete :delete-self
50 :move-self :moved-from :moved-to :move
53 (deftype inotify-add-flag ()
54 "Valid flags for the WATCH function."
55 '(or inotify-add/read-flag
56 (member :dont-follow :mask-add :oneshot :onlydir)))
58 (deftype inotify-read-flag ()
59 "Valid flags which are returned from READ-EVENT."
60 '(or inotify-add/read-flag
61 (member :ignored :isdir :q-overflow :unmount)))
63 (defcfun ("inotify_init" c-inotify-init) :int
64 "Initialises a new inotify event queue.")
66 (defcfun ("inotify_add_watch" c-inotify-add-watch) :int
67 "Watches a path on a event queue."
72 (defcfun ("inotify_rm_watch" c-inotify-rm-watch) :int
73 "Removes a watched path from a event queue."
77 (binary-types:define-signed int #.(cffi:foreign-type-size :int))
79 (binary-types:define-binary-struct inotify-event ()
80 "An inotify native event structure.
81 WD is the watch/file descriptor,
82 MASK is the (parsed) combination of events,
83 COOKIE is a unique integer which connects related events,
84 NAME optionally identifies a file relative to a watched directory."
85 (wd 0 :binary-type int)
86 (mask 0 :binary-type binary-types:u32)
87 (cookie 0 :binary-type binary-types:u32)
90 (defstruct (inotify-instance
91 (:constructor make-inotify-instance ())
92 (:conc-name inotify-))
93 "Contains the stream and file descriptor for a inotify instance."
98 ;;;; initialisation and stuff
100 (defun read-new-value (&optional (stream *query-io*))
101 "READs a value from the STREAM and returns it (wrapped in a list)."
102 (format stream "Enter a new value: ~%")
103 (list (read *query-io*)))
105 (defun init-endian ()
106 "Initialises the endianess for the BINARY-TYPES library. Is automatically
107 called when the library is loaded."
108 (setf binary-types:*endian*
109 (restart-case #+little-endian :little-endian
110 #+big-endian :big-endian
111 #-(or little-endian big-endian) (error "unknown endianess")
113 :report "Enter a correct value (either :LITTLE-ENDIAN or :BIG-ENDIAN)."
114 :interactive read-new-value
115 ;; TODO: better way to test for correct value/retry values?
117 ((:little-endian :big-endian) value)
118 (T (error "wrong value supplied (not :LITTLE-ENDIAN or :BIG-ENDIAN)")))))))
120 ;; initialise the endianess
121 (eval-when (:compile-toplevel :load-toplevel :execute)
124 ;;;; basic wrapping of the API
126 (defun read-raw-event-from-stream (stream)
127 "Reads a raw event from the inotify stream."
128 (let* ((event (binary-types:read-binary 'inotify-event stream))
129 (len (binary-types:read-binary 'binary-types:u32 stream)))
131 (with-slots (name) event
132 (setf name (binary-types:read-binary-string stream
134 :terminators '(0)))))
137 (defun read-event-from-stream (stream)
138 "Reads a event from the inotify stream and converts bitmasks on reading."
139 (let ((event (read-raw-event-from-stream stream)))
140 (with-slots (mask) event
141 (setf mask (foreign-bitfield-symbols 'inotify-flag mask)))
144 (defun set-nonblocking (fd nonblocking)
145 "Enables or disables NONBLOCKING mode on a file descriptor FD."
146 (let ((flags (sb-posix:fcntl fd sb-posix:f-getfl)))
147 ;; an error is raised if this fails, so we don't have to do it ourselves
148 (sb-posix:fcntl fd sb-posix:f-setfl
149 (funcall (if nonblocking #'logior #'logxor)
150 flags sb-posix:o-nonblock)))
153 (defun init-unregistered-notify (notify &optional (nonblocking T))
154 "Creates a new inotify event queue. If NONBLOCKING is set (default),
155 the file descriptor is set to non-blocking I/O."
156 (let ((result (c-inotify-init)))
157 (when (minusp result)
158 (error "inotify_init failed: ~A" result))
159 (with-slots (fd stream (non-block nonblocking)) notify
161 ;; file descriptor is collected with auto-close
165 (set-nonblocking fd T)
166 (setf non-block nonblocking))
168 (sb-sys:make-fd-stream
171 :element-type '(unsigned-byte 8)
172 :name (format NIL "inotify event queue ~A" fd)
174 :buffering (if nonblocking :none :full))))
175 ;; if stream is constructed, gc'ing it will cleanup the file descriptor
177 (sb-posix:close fd)))))
180 (defun make-unregistered-notify ()
181 "Creates a new unregistered NOTIFY instance."
182 (init-unregistered-notify (make-inotify-instance)))
184 (defun close-notify (notify)
185 "Closes the inotify event queue."
186 (close (inotify-stream notify))
189 (defun watch-raw (notify pathname flags)
190 "Adds PATHNAME (either pathname or string) to be watched. FLAGS
191 determines how exactly (see inotify(7) for detailed information).
192 Returns a handle which can be used with UNWATCH-RAW."
193 (let ((path (princ-to-string pathname))
195 (setf result (c-inotify-add-watch
199 (list (foreign-bitfield-value 'inotify-flag flags))
200 (keyword (foreign-bitfield-value 'inotify-flag
203 (when (minusp result)
204 (error "inotify_add_watch failed: ~A" result))
207 (defun unwatch-raw (notify handle)
208 "Disables watching the path associated with HANDLE."
209 (let ((result (c-inotify-rm-watch (inotify-fd notify) handle)))
210 (when (minusp result)
211 (error "inotify_rm_watch failed: ~A" result)))
214 ;;;; support functions, making life easier
216 (defstruct (registered-inotify-instance
217 (:include inotify-instance)
218 (:constructor make-registered-inotify-instance ())
219 (:conc-name inotify-))
220 "Additionally to the information in INOTIFY-INSTANCE, records watched
221 paths in a dictionary."
224 (defun make-notify (&optional (nonblocking T))
225 "Creates a new registered NOTIFY instance. In NONBLOCKING mode, the file
226 descriptor is set to non-blocking mode."
227 (let ((result (make-registered-inotify-instance)))
228 (init-unregistered-notify result nonblocking)
229 (with-slots (watched) result
230 (setf watched (make-hash-table :test 'equal)))
233 (defun watchedp (notify pathname)
234 "Returns the tuple (HANDLE . FLAGS) if PATHNAME is being watched by NOTIFY,
236 (awhen (gethash pathname (inotify-watched notify))
237 (values (car it) (cdr it))))
239 ;; TODO: handle additional flags, save only list of flags
240 (defun watch (notify pathname flags)
241 "Adds PATHNAME (either pathname or string) to be watched and records the
242 watched paths. FLAGS determines how exactly (see inotify(7) for detailed
243 information). Returns a handle which can be used with UNWATCH."
244 (let ((handle (watch-raw notify pathname flags)))
245 (with-slots (watched) notify
246 (setf (gethash pathname watched) (cons handle flags)))
249 (defun unwatch (notify &key pathname handle)
250 "Disables watching the path associated with the supplied HANDLE or PATHNAME."
251 (unless (or pathname handle)
252 (error "either PATHNAME or HANDLE has to be specified"))
254 (unwatch-raw notify handle)
255 (let ((handle (watchedp notify pathname)))
257 (error "PATHNAME ~S isn't being watched" pathname))
258 (unwatch-raw notify handle)
259 (remhash pathname (inotify-watched notify))))
262 (defun list-watched (notify)
263 "Returns a list of all watched pathnames in particular order."
265 (maphash (lambda (k v)
268 (inotify-watched notify))
271 (defun unix-eagainp (fd-stream)
272 "Returns T on a FD-STREAM if trying to read from the stream raised a EAGAIN
274 (multiple-value-bind (result error)
275 (sb-unix:unix-read (sb-sys:fd-stream-fd fd-stream) NIL 0)
276 (declare (ignore result))
277 (= error sb-unix:eagain)))
279 (defun event-availablep (notify)
280 "Returns T if an event is available on the queue."
281 (if (inotify-nonblocking notify)
282 (not (unix-eagainp (inotify-stream notify)))
283 (listen (inotify-stream notify))))
285 (defun read-event (notify)
286 "Reads an event from the queue. Blocks if no event is available."
287 (read-event-from-stream (inotify-stream notify)))
289 (defun next-event (notify)
290 "Reads an event from the queue. Returns NIL if none is available."
291 (when (event-availablep notify)
292 (read-event notify)))
294 (defmacro! do-events ((var o!notify) &body body)
295 "Loops BODY with VAR bound to the events retrieved from NOTIFY. The macro
296 uses NEXT-EVENT, so that reading an event won't block."
297 `(loop as ,var = (next-event ,g!notify)
301 (defun next-events (notify)
302 "Reads all available events from the queue. Returns a list of events."
304 (do-events (event notify)