source: branches/samba-3.5.x/source3/smbd/notify_inotify.c

Last change on this file was 414, checked in by Herwig Bauernfeind, 15 years ago

Samba 3.5.0: Initial import
File size: 10.6 KB
Line 
1/*
2 Unix SMB/CIFS implementation.
3
4 Copyright (C) Andrew Tridgell 2006
5
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 3 of the License, or
9 (at your option) any later version.
10
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.
15
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
18*/
19
20/*
21 notify implementation using inotify
22*/
23
24#include "includes.h"
25
26#ifdef HAVE_INOTIFY
27
28#if HAVE_SYS_INOTIFY_H
29#include <sys/inotify.h>
30#else
31
32#ifdef HAVE_ASM_TYPES_H
33#include <asm/types.h>
34#endif
35
36#ifndef HAVE_INOTIFY_INIT
37
38#include <linux/inotify.h>
39#include <asm/unistd.h>
40
41
42/*
43 glibc doesn't define these functions yet (as of March 2006)
44*/
45static int inotify_init(void)
46{
47 return syscall(__NR_inotify_init);
48}
49
50static int inotify_add_watch(int fd, const char *path, __u32 mask)
51{
52 return syscall(__NR_inotify_add_watch, fd, path, mask);
53}
54
55static int inotify_rm_watch(int fd, int wd)
56{
57 return syscall(__NR_inotify_rm_watch, fd, wd);
58}
59#else
60
61#include <sys/inotify.h>
62
63#endif
64#endif
65
66/* older glibc headers don't have these defines either */
67#ifndef IN_ONLYDIR
68#define IN_ONLYDIR 0x01000000
69#endif
70#ifndef IN_MASK_ADD
71#define IN_MASK_ADD 0x20000000
72#endif
73
74struct inotify_private {
75 struct sys_notify_context *ctx;
76 int fd;
77 struct inotify_watch_context *watches;
78};
79
80struct inotify_watch_context {
81 struct inotify_watch_context *next, *prev;
82 struct inotify_private *in;
83 int wd;
84 void (*callback)(struct sys_notify_context *ctx,
85 void *private_data,
86 struct notify_event *ev);
87 void *private_data;
88 uint32_t mask; /* the inotify mask */
89 uint32_t filter; /* the windows completion filter */
90 const char *path;
91};
92
93
94/*
95 destroy the inotify private context
96*/
97static int inotify_destructor(struct inotify_private *in)
98{
99 close(in->fd);
100 return 0;
101}
102
103
104/*
105 see if a particular event from inotify really does match a requested
106 notify event in SMB
107*/
108static bool filter_match(struct inotify_watch_context *w,
109 struct inotify_event *e)
110{
111 DEBUG(10, ("filter_match: e->mask=%x, w->mask=%x, w->filter=%x\n",
112 e->mask, w->mask, w->filter));
113
114 if ((e->mask & w->mask) == 0) {
115 /* this happens because inotify_add_watch() coalesces watches on the same
116 path, oring their masks together */
117 return False;
118 }
119
120 /* SMB separates the filters for files and directories */
121 if (e->mask & IN_ISDIR) {
122 if ((w->filter & FILE_NOTIFY_CHANGE_DIR_NAME) == 0) {
123 return False;
124 }
125 } else {
126 if ((e->mask & IN_ATTRIB) &&
127 (w->filter & (FILE_NOTIFY_CHANGE_ATTRIBUTES|
128 FILE_NOTIFY_CHANGE_LAST_WRITE|
129 FILE_NOTIFY_CHANGE_LAST_ACCESS|
130 FILE_NOTIFY_CHANGE_EA|
131 FILE_NOTIFY_CHANGE_SECURITY))) {
132 return True;
133 }
134 if ((e->mask & IN_MODIFY) &&
135 (w->filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)) {
136 return True;
137 }
138 if ((w->filter & FILE_NOTIFY_CHANGE_FILE_NAME) == 0) {
139 return False;
140 }
141 }
142
143 return True;
144}
145
146
147
148/*
149 dispatch one inotify event
150
151 the cookies are used to correctly handle renames
152*/
153static void inotify_dispatch(struct inotify_private *in,
154 struct inotify_event *e,
155 uint32_t prev_cookie,
156 struct inotify_event *e2)
157{
158 struct inotify_watch_context *w, *next;
159 struct notify_event ne;
160
161 DEBUG(10, ("inotify_dispatch called with mask=%x, name=[%s]\n",
162 e->mask, e->len ? e->name : ""));
163
164 /* ignore extraneous events, such as unmount and IN_IGNORED events */
165 if ((e->mask & (IN_ATTRIB|IN_MODIFY|IN_CREATE|IN_DELETE|
166 IN_MOVED_FROM|IN_MOVED_TO)) == 0) {
167 return;
168 }
169
170 /* map the inotify mask to a action. This gets complicated for
171 renames */
172 if (e->mask & IN_CREATE) {
173 ne.action = NOTIFY_ACTION_ADDED;
174 } else if (e->mask & IN_DELETE) {
175 ne.action = NOTIFY_ACTION_REMOVED;
176 } else if (e->mask & IN_MOVED_FROM) {
177 if (e2 != NULL && e2->cookie == e->cookie) {
178 ne.action = NOTIFY_ACTION_OLD_NAME;
179 } else {
180 ne.action = NOTIFY_ACTION_REMOVED;
181 }
182 } else if (e->mask & IN_MOVED_TO) {
183 if (e->cookie == prev_cookie) {
184 ne.action = NOTIFY_ACTION_NEW_NAME;
185 } else {
186 ne.action = NOTIFY_ACTION_ADDED;
187 }
188 } else {
189 ne.action = NOTIFY_ACTION_MODIFIED;
190 }
191 ne.path = e->name;
192
193 DEBUG(10, ("inotify_dispatch: ne.action = %d, ne.path = %s\n",
194 ne.action, ne.path));
195
196 /* find any watches that have this watch descriptor */
197 for (w=in->watches;w;w=next) {
198 next = w->next;
199 if (w->wd == e->wd && filter_match(w, e)) {
200 w->callback(in->ctx, w->private_data, &ne);
201 }
202 }
203
204 /* SMB expects a file rename to generate three events, two for
205 the rename and the other for a modify of the
206 destination. Strange! */
207 if (ne.action != NOTIFY_ACTION_NEW_NAME ||
208 (e->mask & IN_ISDIR) != 0) {
209 return;
210 }
211
212 ne.action = NOTIFY_ACTION_MODIFIED;
213 e->mask = IN_ATTRIB;
214
215 for (w=in->watches;w;w=next) {
216 next = w->next;
217 if (w->wd == e->wd && filter_match(w, e) &&
218 !(w->filter & FILE_NOTIFY_CHANGE_CREATION)) {
219 w->callback(in->ctx, w->private_data, &ne);
220 }
221 }
222}
223
224/*
225 called when the kernel has some events for us
226*/
227static void inotify_handler(struct event_context *ev, struct fd_event *fde,
228 uint16_t flags, void *private_data)
229{
230 struct inotify_private *in = talloc_get_type(private_data,
231 struct inotify_private);
232 int bufsize = 0;
233 struct inotify_event *e0, *e;
234 uint32_t prev_cookie=0;
235 NTSTATUS status;
236
237 /*
238 we must use FIONREAD as we cannot predict the length of the
239 filenames, and thus can't know how much to allocate
240 otherwise
241 */
242 if (ioctl(in->fd, FIONREAD, &bufsize) != 0 ||
243 bufsize == 0) {
244 DEBUG(0,("No data on inotify fd?!\n"));
245 TALLOC_FREE(fde);
246 return;
247 }
248
249 e0 = e = (struct inotify_event *)TALLOC_SIZE(in, bufsize);
250 if (e == NULL) return;
251
252 status = read_data(in->fd, (char *)e0, bufsize);
253 if (!NT_STATUS_IS_OK(status)) {
254 DEBUG(0,("Failed to read all inotify data - %s\n",
255 nt_errstr(status)));
256 talloc_free(e0);
257 /* the inotify fd will now be out of sync,
258 * can't keep reading data off it */
259 TALLOC_FREE(fde);
260 return;
261 }
262
263 /* we can get more than one event in the buffer */
264 while (e && (bufsize >= sizeof(*e))) {
265 struct inotify_event *e2 = NULL;
266 bufsize -= e->len + sizeof(*e);
267 if (bufsize >= sizeof(*e)) {
268 e2 = (struct inotify_event *)(e->len + sizeof(*e) + (char *)e);
269 }
270 inotify_dispatch(in, e, prev_cookie, e2);
271 prev_cookie = e->cookie;
272 e = e2;
273 }
274
275 talloc_free(e0);
276}
277
278/*
279 setup the inotify handle - called the first time a watch is added on
280 this context
281*/
282static NTSTATUS inotify_setup(struct sys_notify_context *ctx)
283{
284 struct inotify_private *in;
285
286 if (!lp_parm_bool(-1, "notify", "inotify", True)) {
287 return NT_STATUS_INVALID_SYSTEM_SERVICE;
288 }
289
290 in = talloc(ctx, struct inotify_private);
291 NT_STATUS_HAVE_NO_MEMORY(in);
292 in->fd = inotify_init();
293 if (in->fd == -1) {
294 DEBUG(0,("Failed to init inotify - %s\n", strerror(errno)));
295 talloc_free(in);
296 return map_nt_error_from_unix(errno);
297 }
298 in->ctx = ctx;
299 in->watches = NULL;
300
301 ctx->private_data = in;
302 talloc_set_destructor(in, inotify_destructor);
303
304 /* add a event waiting for the inotify fd to be readable */
305 event_add_fd(ctx->ev, in, in->fd, EVENT_FD_READ, inotify_handler, in);
306
307 return NT_STATUS_OK;
308}
309
310
311/*
312 map from a change notify mask to a inotify mask. Remove any bits
313 which we can handle
314*/
315static const struct {
316 uint32_t notify_mask;
317 uint32_t inotify_mask;
318} inotify_mapping[] = {
319 {FILE_NOTIFY_CHANGE_FILE_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
320 {FILE_NOTIFY_CHANGE_DIR_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
321 {FILE_NOTIFY_CHANGE_ATTRIBUTES, IN_ATTRIB|IN_MOVED_TO|IN_MOVED_FROM|IN_MODIFY},
322 {FILE_NOTIFY_CHANGE_LAST_WRITE, IN_ATTRIB},
323 {FILE_NOTIFY_CHANGE_LAST_ACCESS, IN_ATTRIB},
324 {FILE_NOTIFY_CHANGE_EA, IN_ATTRIB},
325 {FILE_NOTIFY_CHANGE_SECURITY, IN_ATTRIB}
326};
327
328static uint32_t inotify_map(struct notify_entry *e)
329{
330 int i;
331 uint32_t out=0;
332 for (i=0;i<ARRAY_SIZE(inotify_mapping);i++) {
333 if (inotify_mapping[i].notify_mask & e->filter) {
334 out |= inotify_mapping[i].inotify_mask;
335 e->filter &= ~inotify_mapping[i].notify_mask;
336 }
337 }
338 return out;
339}
340
341/*
342 destroy a watch
343*/
344static int watch_destructor(struct inotify_watch_context *w)
345{
346 struct inotify_private *in = w->in;
347 int wd = w->wd;
348 DLIST_REMOVE(w->in->watches, w);
349
350 /* only rm the watch if its the last one with this wd */
351 for (w=in->watches;w;w=w->next) {
352 if (w->wd == wd) break;
353 }
354 if (w == NULL) {
355 DEBUG(10, ("Deleting inotify watch %d\n", wd));
356 if (inotify_rm_watch(in->fd, wd) == -1) {
357 DEBUG(1, ("inotify_rm_watch returned %s\n",
358 strerror(errno)));
359 }
360
361 }
362 return 0;
363}
364
365
366/*
367 add a watch. The watch is removed when the caller calls
368 talloc_free() on *handle
369*/
370NTSTATUS inotify_watch(struct sys_notify_context *ctx,
371 struct notify_entry *e,
372 void (*callback)(struct sys_notify_context *ctx,
373 void *private_data,
374 struct notify_event *ev),
375 void *private_data,
376 void *handle_p)
377{
378 struct inotify_private *in;
379 int wd;
380 uint32_t mask;
381 struct inotify_watch_context *w;
382 uint32_t filter = e->filter;
383 void **handle = (void **)handle_p;
384
385 /* maybe setup the inotify fd */
386 if (ctx->private_data == NULL) {
387 NTSTATUS status;
388 status = inotify_setup(ctx);
389 NT_STATUS_NOT_OK_RETURN(status);
390 }
391
392 in = talloc_get_type(ctx->private_data, struct inotify_private);
393
394 mask = inotify_map(e);
395 if (mask == 0) {
396 /* this filter can't be handled by inotify */
397 return NT_STATUS_INVALID_PARAMETER;
398 }
399
400 /* using IN_MASK_ADD allows us to cope with inotify() returning the same
401 watch descriptor for muliple watches on the same path */
402 mask |= (IN_MASK_ADD | IN_ONLYDIR);
403
404 /* get a new watch descriptor for this path */
405 wd = inotify_add_watch(in->fd, e->path, mask);
406 if (wd == -1) {
407 e->filter = filter;
408 DEBUG(1, ("inotify_add_watch returned %s\n", strerror(errno)));
409 return map_nt_error_from_unix(errno);
410 }
411
412 DEBUG(10, ("inotify_add_watch for %s mask %x returned wd %d\n",
413 e->path, mask, wd));
414
415 w = talloc(in, struct inotify_watch_context);
416 if (w == NULL) {
417 inotify_rm_watch(in->fd, wd);
418 e->filter = filter;
419 return NT_STATUS_NO_MEMORY;
420 }
421
422 w->in = in;
423 w->wd = wd;
424 w->callback = callback;
425 w->private_data = private_data;
426 w->mask = mask;
427 w->filter = filter;
428 w->path = talloc_strdup(w, e->path);
429 if (w->path == NULL) {
430 inotify_rm_watch(in->fd, wd);
431 e->filter = filter;
432 return NT_STATUS_NO_MEMORY;
433 }
434
435 (*handle) = w;
436
437 DLIST_ADD(in->watches, w);
438
439 /* the caller frees the handle to stop watching */
440 talloc_set_destructor(w, watch_destructor);
441
442 return NT_STATUS_OK;
443}
444
445#endif
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