source: trunk/server/source3/smbd/notify_inotify.c

Last change on this file was 745, checked in by Silvan Scherrer, 13 years ago

Samba Server: updated trunk to 3.6.0
File size: 11.2 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#include "../librpc/gen_ndr/notify.h"
26#include "smbd/smbd.h"
27
28#ifdef HAVE_INOTIFY
29
30#if HAVE_SYS_INOTIFY_H
31#include <sys/inotify.h>
32#else
33
34#ifdef HAVE_ASM_TYPES_H
35#include <asm/types.h>
36#endif
37
38#ifndef HAVE_INOTIFY_INIT
39
40#include <linux/inotify.h>
41#include <asm/unistd.h>
42
43
44/*
45 glibc doesn't define these functions yet (as of March 2006)
46*/
47static int inotify_init(void)
48{
49 return syscall(__NR_inotify_init);
50}
51
52static int inotify_add_watch(int fd, const char *path, __u32 mask)
53{
54 return syscall(__NR_inotify_add_watch, fd, path, mask);
55}
56
57static int inotify_rm_watch(int fd, int wd)
58{
59 return syscall(__NR_inotify_rm_watch, fd, wd);
60}
61#else
62
63#include <sys/inotify.h>
64
65#endif
66#endif
67
68/* older glibc headers don't have these defines either */
69#ifndef IN_ONLYDIR
70#define IN_ONLYDIR 0x01000000
71#endif
72#ifndef IN_MASK_ADD
73#define IN_MASK_ADD 0x20000000
74#endif
75
76struct inotify_private {
77 struct sys_notify_context *ctx;
78 int fd;
79 struct inotify_watch_context *watches;
80};
81
82struct inotify_watch_context {
83 struct inotify_watch_context *next, *prev;
84 struct inotify_private *in;
85 int wd;
86 void (*callback)(struct sys_notify_context *ctx,
87 void *private_data,
88 struct notify_event *ev);
89 void *private_data;
90 uint32_t mask; /* the inotify mask */
91 uint32_t filter; /* the windows completion filter */
92 const char *path;
93};
94
95
96/*
97 destroy the inotify private context
98*/
99static int inotify_destructor(struct inotify_private *in)
100{
101 close(in->fd);
102 return 0;
103}
104
105
106/*
107 see if a particular event from inotify really does match a requested
108 notify event in SMB
109*/
110static bool filter_match(struct inotify_watch_context *w,
111 struct inotify_event *e)
112{
113 DEBUG(10, ("filter_match: e->mask=%x, w->mask=%x, w->filter=%x\n",
114 e->mask, w->mask, w->filter));
115
116 if ((e->mask & w->mask) == 0) {
117 /* this happens because inotify_add_watch() coalesces watches on the same
118 path, oring their masks together */
119 return False;
120 }
121
122 /* SMB separates the filters for files and directories */
123 if (e->mask & IN_ISDIR) {
124 if ((w->filter & FILE_NOTIFY_CHANGE_DIR_NAME) == 0) {
125 return False;
126 }
127 } else {
128 if ((e->mask & IN_ATTRIB) &&
129 (w->filter & (FILE_NOTIFY_CHANGE_ATTRIBUTES|
130 FILE_NOTIFY_CHANGE_LAST_WRITE|
131 FILE_NOTIFY_CHANGE_LAST_ACCESS|
132 FILE_NOTIFY_CHANGE_EA|
133 FILE_NOTIFY_CHANGE_SECURITY))) {
134 return True;
135 }
136 if ((e->mask & IN_MODIFY) &&
137 (w->filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)) {
138 return True;
139 }
140 if ((w->filter & FILE_NOTIFY_CHANGE_FILE_NAME) == 0) {
141 return False;
142 }
143 }
144
145 return True;
146}
147
148
149
150/*
151 dispatch one inotify event
152
153 the cookies are used to correctly handle renames
154*/
155static void inotify_dispatch(struct inotify_private *in,
156 struct inotify_event *e,
157 uint32_t prev_cookie,
158 struct inotify_event *e2)
159{
160 struct inotify_watch_context *w, *next;
161 struct notify_event ne;
162
163 DEBUG(10, ("inotify_dispatch called with mask=%x, name=[%s]\n",
164 e->mask, e->len ? e->name : ""));
165
166 /* ignore extraneous events, such as unmount and IN_IGNORED events */
167 if ((e->mask & (IN_ATTRIB|IN_MODIFY|IN_CREATE|IN_DELETE|
168 IN_MOVED_FROM|IN_MOVED_TO)) == 0) {
169 return;
170 }
171
172 /* map the inotify mask to a action. This gets complicated for
173 renames */
174 if (e->mask & IN_CREATE) {
175 ne.action = NOTIFY_ACTION_ADDED;
176 } else if (e->mask & IN_DELETE) {
177 ne.action = NOTIFY_ACTION_REMOVED;
178 } else if (e->mask & IN_MOVED_FROM) {
179 if (e2 != NULL && e2->cookie == e->cookie) {
180 ne.action = NOTIFY_ACTION_OLD_NAME;
181 } else {
182 ne.action = NOTIFY_ACTION_REMOVED;
183 }
184 } else if (e->mask & IN_MOVED_TO) {
185 if (e->cookie == prev_cookie) {
186 ne.action = NOTIFY_ACTION_NEW_NAME;
187 } else {
188 ne.action = NOTIFY_ACTION_ADDED;
189 }
190 } else {
191 ne.action = NOTIFY_ACTION_MODIFIED;
192 }
193 ne.path = e->name;
194
195 DEBUG(10, ("inotify_dispatch: ne.action = %d, ne.path = %s\n",
196 ne.action, ne.path));
197
198 /* find any watches that have this watch descriptor */
199 for (w=in->watches;w;w=next) {
200 next = w->next;
201 if (w->wd == e->wd && filter_match(w, e)) {
202 w->callback(in->ctx, w->private_data, &ne);
203 }
204 }
205
206 /* SMB expects a file rename to generate three events, two for
207 the rename and the other for a modify of the
208 destination. Strange! */
209 if (ne.action != NOTIFY_ACTION_NEW_NAME ||
210 (e->mask & IN_ISDIR) != 0) {
211 return;
212 }
213
214 ne.action = NOTIFY_ACTION_MODIFIED;
215 e->mask = IN_ATTRIB;
216
217 for (w=in->watches;w;w=next) {
218 next = w->next;
219 if (w->wd == e->wd && filter_match(w, e) &&
220 !(w->filter & FILE_NOTIFY_CHANGE_CREATION)) {
221 w->callback(in->ctx, w->private_data, &ne);
222 }
223 }
224}
225
226/*
227 called when the kernel has some events for us
228*/
229static void inotify_handler(struct event_context *ev, struct fd_event *fde,
230 uint16_t flags, void *private_data)
231{
232 struct inotify_private *in = talloc_get_type(private_data,
233 struct inotify_private);
234 int bufsize = 0;
235 struct inotify_event *e0, *e;
236 uint32_t prev_cookie=0;
237 NTSTATUS status;
238
239 /*
240 we must use FIONREAD as we cannot predict the length of the
241 filenames, and thus can't know how much to allocate
242 otherwise
243 */
244 if (ioctl(in->fd, FIONREAD, &bufsize) != 0 ||
245 bufsize == 0) {
246 DEBUG(0,("No data on inotify fd?!\n"));
247 TALLOC_FREE(fde);
248 return;
249 }
250
251 e0 = e = (struct inotify_event *)TALLOC_SIZE(in, bufsize + 1);
252 if (e == NULL) return;
253 ((uint8_t *)e)[bufsize] = '\0';
254
255 status = read_data(in->fd, (char *)e0, bufsize);
256 if (!NT_STATUS_IS_OK(status)) {
257 DEBUG(0,("Failed to read all inotify data - %s\n",
258 nt_errstr(status)));
259 talloc_free(e0);
260 /* the inotify fd will now be out of sync,
261 * can't keep reading data off it */
262 TALLOC_FREE(fde);
263 return;
264 }
265
266 /* we can get more than one event in the buffer */
267 while (e && (bufsize >= sizeof(*e))) {
268 struct inotify_event *e2 = NULL;
269 bufsize -= e->len + sizeof(*e);
270 if (bufsize >= sizeof(*e)) {
271 e2 = (struct inotify_event *)(e->len + sizeof(*e) + (char *)e);
272 }
273 inotify_dispatch(in, e, prev_cookie, e2);
274 prev_cookie = e->cookie;
275 e = e2;
276 }
277
278 talloc_free(e0);
279}
280
281/*
282 setup the inotify handle - called the first time a watch is added on
283 this context
284*/
285static NTSTATUS inotify_setup(struct sys_notify_context *ctx)
286{
287 struct inotify_private *in;
288
289 if (!lp_parm_bool(-1, "notify", "inotify", True)) {
290 return NT_STATUS_INVALID_SYSTEM_SERVICE;
291 }
292
293 in = talloc(ctx, struct inotify_private);
294 NT_STATUS_HAVE_NO_MEMORY(in);
295 in->fd = inotify_init();
296 if (in->fd == -1) {
297 DEBUG(0,("Failed to init inotify - %s\n", strerror(errno)));
298 talloc_free(in);
299 return map_nt_error_from_unix(errno);
300 }
301 in->ctx = ctx;
302 in->watches = NULL;
303
304 ctx->private_data = in;
305 talloc_set_destructor(in, inotify_destructor);
306
307 /* add a event waiting for the inotify fd to be readable */
308 event_add_fd(ctx->ev, in, in->fd, EVENT_FD_READ, inotify_handler, in);
309
310 return NT_STATUS_OK;
311}
312
313
314/*
315 map from a change notify mask to a inotify mask. Remove any bits
316 which we can handle
317*/
318static const struct {
319 uint32_t notify_mask;
320 uint32_t inotify_mask;
321} inotify_mapping[] = {
322 {FILE_NOTIFY_CHANGE_FILE_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
323 {FILE_NOTIFY_CHANGE_DIR_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
324 {FILE_NOTIFY_CHANGE_ATTRIBUTES, IN_ATTRIB|IN_MOVED_TO|IN_MOVED_FROM|IN_MODIFY},
325 {FILE_NOTIFY_CHANGE_LAST_WRITE, IN_ATTRIB},
326 {FILE_NOTIFY_CHANGE_LAST_ACCESS, IN_ATTRIB},
327 {FILE_NOTIFY_CHANGE_EA, IN_ATTRIB},
328 {FILE_NOTIFY_CHANGE_SECURITY, IN_ATTRIB}
329};
330
331static uint32_t inotify_map(struct notify_entry *e)
332{
333 int i;
334 uint32_t out=0;
335 for (i=0;i<ARRAY_SIZE(inotify_mapping);i++) {
336 if (inotify_mapping[i].notify_mask & e->filter) {
337 out |= inotify_mapping[i].inotify_mask;
338 e->filter &= ~inotify_mapping[i].notify_mask;
339 }
340 }
341 return out;
342}
343
344/*
345 destroy a watch
346*/
347static int watch_destructor(struct inotify_watch_context *w)
348{
349 struct inotify_private *in = w->in;
350 int wd = w->wd;
351 DLIST_REMOVE(w->in->watches, w);
352
353 /* only rm the watch if its the last one with this wd */
354 for (w=in->watches;w;w=w->next) {
355 if (w->wd == wd) break;
356 }
357 if (w == NULL) {
358 DEBUG(10, ("Deleting inotify watch %d\n", wd));
359 if (inotify_rm_watch(in->fd, wd) == -1) {
360 DEBUG(1, ("inotify_rm_watch returned %s\n",
361 strerror(errno)));
362 }
363
364 }
365 return 0;
366}
367
368
369/*
370 add a watch. The watch is removed when the caller calls
371 talloc_free() on *handle
372*/
373NTSTATUS inotify_watch(struct sys_notify_context *ctx,
374 struct notify_entry *e,
375 void (*callback)(struct sys_notify_context *ctx,
376 void *private_data,
377 struct notify_event *ev),
378 void *private_data,
379 void *handle_p)
380{
381 struct inotify_private *in;
382 int wd;
383 uint32_t mask;
384 struct inotify_watch_context *w;
385 uint32_t filter = e->filter;
386 void **handle = (void **)handle_p;
387
388 /* maybe setup the inotify fd */
389 if (ctx->private_data == NULL) {
390 NTSTATUS status;
391 status = inotify_setup(ctx);
392 NT_STATUS_NOT_OK_RETURN(status);
393 }
394
395 in = talloc_get_type(ctx->private_data, struct inotify_private);
396
397 mask = inotify_map(e);
398 if (mask == 0) {
399 /* this filter can't be handled by inotify */
400 return NT_STATUS_INVALID_PARAMETER;
401 }
402
403 /* using IN_MASK_ADD allows us to cope with inotify() returning the same
404 watch descriptor for muliple watches on the same path */
405 mask |= (IN_MASK_ADD | IN_ONLYDIR);
406
407 /* get a new watch descriptor for this path */
408 wd = inotify_add_watch(in->fd, e->path, mask);
409 if (wd == -1) {
410 e->filter = filter;
411 DEBUG(1, ("inotify_add_watch returned %s\n", strerror(errno)));
412 return map_nt_error_from_unix(errno);
413 }
414
415 DEBUG(10, ("inotify_add_watch for %s mask %x returned wd %d\n",
416 e->path, mask, wd));
417
418 w = talloc(in, struct inotify_watch_context);
419 if (w == NULL) {
420 inotify_rm_watch(in->fd, wd);
421 e->filter = filter;
422 return NT_STATUS_NO_MEMORY;
423 }
424
425 w->in = in;
426 w->wd = wd;
427 w->callback = callback;
428 w->private_data = private_data;
429 w->mask = mask;
430 w->filter = filter;
431 w->path = talloc_strdup(w, e->path);
432 if (w->path == NULL) {
433 inotify_rm_watch(in->fd, wd);
434 e->filter = filter;
435 return NT_STATUS_NO_MEMORY;
436 }
437
438 (*handle) = w;
439
440 DLIST_ADD(in->watches, w);
441
442 /* the caller frees the handle to stop watching */
443 talloc_set_destructor(w, watch_destructor);
444
445 return NT_STATUS_OK;
446}
447
448#endif
Note: See TracBrowser for help on using the repository browser.