2 Unix SMB/CIFS implementation.
4 Copyright (C) Andrew Tridgell 2006
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 notify implementation using inotify
26 #include "system/filesys.h"
27 #include "ntvfs/sysdep/sys_notify.h"
28 #include "lib/events/events.h"
30 #include "dlinklist.h"
32 #include <linux/inotify.h>
33 #include <asm/unistd.h>
35 #ifndef HAVE_INOTIFY_INIT
37 glibc doesn't define these functions yet (as of March 2006)
39 static int inotify_init(void)
41 return syscall(__NR_inotify_init);
44 static int inotify_add_watch(int fd, const char *path, __u32 mask)
46 return syscall(__NR_inotify_add_watch, fd, path, mask);
49 static int inotify_rm_watch(int fd, int wd)
51 return syscall(__NR_inotify_rm_watch, fd, wd);
56 /* older glibc headers don't have these defines either */
58 #define IN_ONLYDIR 0x01000000
61 #define IN_MASK_ADD 0x20000000
64 struct inotify_private {
65 struct sys_notify_context *ctx;
67 struct watch_context *watches;
70 struct watch_context {
71 struct watch_context *next, *prev;
72 struct inotify_private *in;
74 sys_notify_callback_t callback;
81 destroy the inotify private context
83 static int inotify_destructor(void *ptr)
85 struct inotify_private *in = talloc_get_type(ptr, struct inotify_private);
92 dispatch one inotify event
94 the cookies are used to correctly handle renames
96 static void inotify_dispatch(struct inotify_private *in,
97 struct inotify_event *e,
101 struct watch_context *w;
102 struct notify_event ne;
104 /* ignore extraneous events, such as unmount and IN_IGNORED events */
105 if ((e->mask & (IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO)) == 0) {
109 /* map the inotify mask to a action. This gets complicated for
111 if (e->mask & IN_CREATE) {
112 ne.action = NOTIFY_ACTION_ADDED;
113 } else if (e->mask & IN_DELETE) {
114 ne.action = NOTIFY_ACTION_REMOVED;
115 } else if (e->mask & IN_MOVED_FROM) {
116 if (e->cookie == next_cookie) {
117 ne.action = NOTIFY_ACTION_OLD_NAME;
119 ne.action = NOTIFY_ACTION_REMOVED;
121 } else if (e->mask & IN_MOVED_TO) {
122 if (e->cookie == prev_cookie) {
123 ne.action = NOTIFY_ACTION_NEW_NAME;
125 ne.action = NOTIFY_ACTION_ADDED;
128 ne.action = NOTIFY_ACTION_MODIFIED;
132 /* find any watches that have this watch descriptor */
133 for (w=in->watches;w;w=w->next) {
134 /* checking the mask copes with multiple watches */
135 if (w->wd == e->wd && (e->mask & w->mask) != 0) {
136 w->callback(in->ctx, w->private, &ne);
142 called when the kernel has some events for us
144 static void inotify_handler(struct event_context *ev, struct fd_event *fde,
145 uint16_t flags, void *private)
147 struct inotify_private *in = talloc_get_type(private, struct inotify_private);
149 struct inotify_event *e0, *e;
150 uint32_t prev_cookie=0;
153 we must use FIONREAD as we cannot predict the length of the
154 filenames, and thus can't know how much to allocate
157 if (ioctl(in->fd, FIONREAD, &bufsize) != 0 ||
159 DEBUG(0,("No data on inotify fd?!\n"));
163 e0 = e = talloc_size(in, bufsize);
164 if (e == NULL) return;
166 if (read(in->fd, e0, bufsize) != bufsize) {
167 DEBUG(0,("Failed to read all inotify data\n"));
172 /* we can get more than one event in the buffer */
173 while (bufsize >= sizeof(*e)) {
174 struct inotify_event *e2 = NULL;
175 bufsize -= e->len + sizeof(*e);
176 if (bufsize >= sizeof(*e)) {
177 e2 = (struct inotify_event *)(e->len + sizeof(*e) + (char *)e);
179 inotify_dispatch(in, e, prev_cookie, e2?e2->cookie:0);
180 prev_cookie = e->cookie;
188 setup the inotify handle - called the first time a watch is added on
191 static NTSTATUS inotify_setup(struct sys_notify_context *ctx)
193 struct inotify_private *in;
195 in = talloc(ctx, struct inotify_private);
196 NT_STATUS_HAVE_NO_MEMORY(in);
197 in->fd = inotify_init();
199 DEBUG(0,("Failed to init inotify - %s\n", strerror(errno)));
201 return map_nt_error_from_unix(errno);
207 talloc_set_destructor(in, inotify_destructor);
209 /* add a event waiting for the inotify fd to be readable */
210 event_add_fd(ctx->ev, in, in->fd, EVENT_FD_READ, inotify_handler, in);
217 map from a change notify mask to a inotify mask. Remove any bits
220 static const struct {
221 uint32_t notify_mask;
222 uint32_t inotify_mask;
223 } inotify_mapping[] = {
224 {FILE_NOTIFY_CHANGE_FILE_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
225 {FILE_NOTIFY_CHANGE_DIR_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
226 {FILE_NOTIFY_CHANGE_ATTRIBUTES, IN_ATTRIB},
227 {FILE_NOTIFY_CHANGE_SIZE, IN_MODIFY},
228 {FILE_NOTIFY_CHANGE_LAST_WRITE, IN_ATTRIB},
229 {FILE_NOTIFY_CHANGE_EA, IN_ATTRIB},
230 {FILE_NOTIFY_CHANGE_SECURITY, IN_ATTRIB}
233 static uint32_t inotify_map(struct notify_entry *e)
237 for (i=0;i<ARRAY_SIZE(inotify_mapping);i++) {
238 if (inotify_mapping[i].notify_mask & e->filter) {
239 out |= inotify_mapping[i].inotify_mask;
240 e->filter &= ~inotify_mapping[i].notify_mask;
249 static int watch_destructor(void *ptr)
251 struct watch_context *w = talloc_get_type(ptr, struct watch_context);
252 struct inotify_private *in = w->in;
254 DLIST_REMOVE(w->in->watches, w);
256 /* only rm the watch if its the last one with this wd */
257 for (w=in->watches;w;w=w->next) {
258 if (w->wd == wd) break;
261 inotify_rm_watch(in->fd, wd);
268 add a watch. The watch is removed when the caller calls
269 talloc_free() on *handle
271 static NTSTATUS inotify_watch(struct sys_notify_context *ctx, struct notify_entry *e,
272 sys_notify_callback_t callback, void *private,
275 struct inotify_private *in;
278 struct watch_context *w;
279 uint32_t filter = e->filter;
281 /* maybe setup the inotify fd */
282 if (ctx->private == NULL) {
284 status = inotify_setup(ctx);
285 NT_STATUS_NOT_OK_RETURN(status);
288 in = talloc_get_type(ctx->private, struct inotify_private);
290 mask = inotify_map(e);
292 /* this filter can't be handled by inotify */
293 return NT_STATUS_INVALID_PARAMETER;
296 /* using IN_MASK_ADD allows us to cope with inotify() returning the same
297 watch descriptor for muliple watches on the same path */
298 mask |= (IN_MASK_ADD | IN_ONLYDIR);
300 /* get a new watch descriptor for this path */
301 wd = inotify_add_watch(in->fd, e->path, mask);
304 return map_nt_error_from_unix(errno);
307 w = talloc(in, struct watch_context);
309 inotify_rm_watch(in->fd, wd);
311 return NT_STATUS_NO_MEMORY;
316 w->callback = callback;
317 w->private = private;
322 DLIST_ADD(in->watches, w);
324 /* the caller frees the handle to stop watching */
325 talloc_set_destructor(w, watch_destructor);
331 static struct sys_notify_backend inotify = {
333 .notify_watch = inotify_watch
337 initialialise the inotify module
339 NTSTATUS ntvfs_inotify_init(void)
341 /* register ourselves as a system inotify module */
342 return sys_notify_register(&inotify);