source: vendor/current/source3/smbd/notify_inotify.c

Last change on this file was 988, checked in by Silvan Scherrer, 9 years ago

Samba Server: update vendor to version 4.4.3
File size: 10.3 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#include "lib/util/sys_rw_data.h"
28
29#include <sys/inotify.h>
30
31/* glibc < 2.5 headers don't have these defines */
32#ifndef IN_ONLYDIR
33#define IN_ONLYDIR 0x01000000
34#endif
35#ifndef IN_MASK_ADD
36#define IN_MASK_ADD 0x20000000
37#endif
38
39struct inotify_private {
40 struct sys_notify_context *ctx;
41 int fd;
42 struct inotify_watch_context *watches;
43};
44
45struct inotify_watch_context {
46 struct inotify_watch_context *next, *prev;
47 struct inotify_private *in;
48 int wd;
49 void (*callback)(struct sys_notify_context *ctx,
50 void *private_data,
51 struct notify_event *ev);
52 void *private_data;
53 uint32_t mask; /* the inotify mask */
54 uint32_t filter; /* the windows completion filter */
55 const char *path;
56};
57
58
59/*
60 destroy the inotify private context
61*/
62static int inotify_destructor(struct inotify_private *in)
63{
64 close(in->fd);
65 return 0;
66}
67
68
69/*
70 see if a particular event from inotify really does match a requested
71 notify event in SMB
72*/
73static bool filter_match(struct inotify_watch_context *w,
74 struct inotify_event *e)
75{
76 bool ok;
77
78 DEBUG(10, ("filter_match: e->mask=%x, w->mask=%x, w->filter=%x\n",
79 e->mask, w->mask, w->filter));
80
81 if ((e->mask & w->mask) == 0) {
82 /* this happens because inotify_add_watch() coalesces watches on the same
83 path, oring their masks together */
84 return False;
85 }
86
87 /* SMB separates the filters for files and directories */
88 if (e->mask & IN_ISDIR) {
89 ok = ((w->filter & FILE_NOTIFY_CHANGE_DIR_NAME) != 0);
90 return ok;
91 }
92
93 if ((e->mask & IN_ATTRIB) &&
94 (w->filter & (FILE_NOTIFY_CHANGE_ATTRIBUTES|
95 FILE_NOTIFY_CHANGE_LAST_WRITE|
96 FILE_NOTIFY_CHANGE_LAST_ACCESS|
97 FILE_NOTIFY_CHANGE_EA|
98 FILE_NOTIFY_CHANGE_SECURITY))) {
99 return True;
100 }
101 if ((e->mask & IN_MODIFY) &&
102 (w->filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)) {
103 return True;
104 }
105
106 ok = ((w->filter & FILE_NOTIFY_CHANGE_FILE_NAME) != 0);
107 return ok;
108}
109
110
111
112/*
113 dispatch one inotify event
114
115 the cookies are used to correctly handle renames
116*/
117static void inotify_dispatch(struct inotify_private *in,
118 struct inotify_event *e,
119 int prev_wd,
120 uint32_t prev_cookie,
121 struct inotify_event *e2)
122{
123 struct inotify_watch_context *w, *next;
124 struct notify_event ne;
125
126 DEBUG(10, ("inotify_dispatch called with mask=%x, name=[%s]\n",
127 e->mask, e->len ? e->name : ""));
128
129 /* ignore extraneous events, such as unmount and IN_IGNORED events */
130 if ((e->mask & (IN_ATTRIB|IN_MODIFY|IN_CREATE|IN_DELETE|
131 IN_MOVED_FROM|IN_MOVED_TO)) == 0) {
132 return;
133 }
134
135 /* map the inotify mask to a action. This gets complicated for
136 renames */
137 if (e->mask & IN_CREATE) {
138 ne.action = NOTIFY_ACTION_ADDED;
139 } else if (e->mask & IN_DELETE) {
140 ne.action = NOTIFY_ACTION_REMOVED;
141 } else if (e->mask & IN_MOVED_FROM) {
142 if (e2 != NULL && e2->cookie == e->cookie &&
143 e2->wd == e->wd) {
144 ne.action = NOTIFY_ACTION_OLD_NAME;
145 } else {
146 ne.action = NOTIFY_ACTION_REMOVED;
147 }
148 } else if (e->mask & IN_MOVED_TO) {
149 if ((e->cookie == prev_cookie) && (e->wd == prev_wd)) {
150 ne.action = NOTIFY_ACTION_NEW_NAME;
151 } else {
152 ne.action = NOTIFY_ACTION_ADDED;
153 }
154 } else {
155 ne.action = NOTIFY_ACTION_MODIFIED;
156 }
157 ne.path = e->name;
158
159 DEBUG(10, ("inotify_dispatch: ne.action = %d, ne.path = %s\n",
160 ne.action, ne.path));
161
162 /* find any watches that have this watch descriptor */
163 for (w=in->watches;w;w=next) {
164 next = w->next;
165 if (w->wd == e->wd && filter_match(w, e)) {
166 ne.dir = w->path;
167 w->callback(in->ctx, w->private_data, &ne);
168 }
169 }
170
171 if ((ne.action == NOTIFY_ACTION_NEW_NAME) &&
172 ((e->mask & IN_ISDIR) == 0)) {
173
174 /*
175 * SMB expects a file rename to generate three events, two for
176 * the rename and the other for a modify of the
177 * destination. Strange!
178 */
179
180 ne.action = NOTIFY_ACTION_MODIFIED;
181 e->mask = IN_ATTRIB;
182
183 for (w=in->watches;w;w=next) {
184 next = w->next;
185 if (w->wd == e->wd && filter_match(w, e) &&
186 !(w->filter & FILE_NOTIFY_CHANGE_CREATION)) {
187 ne.dir = w->path;
188 w->callback(in->ctx, w->private_data, &ne);
189 }
190 }
191 }
192}
193
194/*
195 called when the kernel has some events for us
196*/
197static void inotify_handler(struct tevent_context *ev, struct tevent_fd *fde,
198 uint16_t flags, void *private_data)
199{
200 struct inotify_private *in = talloc_get_type(private_data,
201 struct inotify_private);
202 int bufsize = 0;
203 struct inotify_event *e0, *e;
204 uint32_t prev_cookie=0;
205 int prev_wd = -1;
206 ssize_t ret;
207
208 /*
209 we must use FIONREAD as we cannot predict the length of the
210 filenames, and thus can't know how much to allocate
211 otherwise
212 */
213 if (ioctl(in->fd, FIONREAD, &bufsize) != 0 ||
214 bufsize == 0) {
215 DEBUG(0,("No data on inotify fd?!\n"));
216 TALLOC_FREE(fde);
217 return;
218 }
219
220 e0 = e = (struct inotify_event *)TALLOC_SIZE(in, bufsize + 1);
221 if (e == NULL) return;
222 ((uint8_t *)e)[bufsize] = '\0';
223
224 ret = read_data(in->fd, e0, bufsize);
225 if (ret != bufsize) {
226 DEBUG(0, ("Failed to read all inotify data - %s\n",
227 strerror(errno)));
228 talloc_free(e0);
229 /* the inotify fd will now be out of sync,
230 * can't keep reading data off it */
231 TALLOC_FREE(fde);
232 return;
233 }
234
235 /* we can get more than one event in the buffer */
236 while (e && (bufsize >= sizeof(*e))) {
237 struct inotify_event *e2 = NULL;
238 bufsize -= e->len + sizeof(*e);
239 if (bufsize >= sizeof(*e)) {
240 e2 = (struct inotify_event *)(e->len + sizeof(*e) + (char *)e);
241 }
242 inotify_dispatch(in, e, prev_wd, prev_cookie, e2);
243 prev_wd = e->wd;
244 prev_cookie = e->cookie;
245 e = e2;
246 }
247
248 talloc_free(e0);
249}
250
251/*
252 setup the inotify handle - called the first time a watch is added on
253 this context
254*/
255static int inotify_setup(struct sys_notify_context *ctx)
256{
257 struct inotify_private *in;
258 struct tevent_fd *fde;
259
260 in = talloc(ctx, struct inotify_private);
261 if (in == NULL) {
262 return ENOMEM;
263 }
264
265 in->fd = inotify_init();
266 if (in->fd == -1) {
267 int ret = errno;
268 DEBUG(0, ("Failed to init inotify - %s\n", strerror(ret)));
269 talloc_free(in);
270 return ret;
271 }
272 in->ctx = ctx;
273 in->watches = NULL;
274
275 ctx->private_data = in;
276 talloc_set_destructor(in, inotify_destructor);
277
278 /* add a event waiting for the inotify fd to be readable */
279 fde = tevent_add_fd(ctx->ev, in, in->fd, TEVENT_FD_READ,
280 inotify_handler, in);
281 if (fde == NULL) {
282 ctx->private_data = NULL;
283 TALLOC_FREE(in);
284 return ENOMEM;
285 }
286 return 0;
287}
288
289
290/*
291 map from a change notify mask to a inotify mask. Remove any bits
292 which we can handle
293*/
294static const struct {
295 uint32_t notify_mask;
296 uint32_t inotify_mask;
297} inotify_mapping[] = {
298 {FILE_NOTIFY_CHANGE_FILE_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
299 {FILE_NOTIFY_CHANGE_DIR_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
300 {FILE_NOTIFY_CHANGE_ATTRIBUTES, IN_ATTRIB|IN_MOVED_TO|IN_MOVED_FROM|IN_MODIFY},
301 {FILE_NOTIFY_CHANGE_LAST_WRITE, IN_ATTRIB},
302 {FILE_NOTIFY_CHANGE_LAST_ACCESS, IN_ATTRIB},
303 {FILE_NOTIFY_CHANGE_EA, IN_ATTRIB},
304 {FILE_NOTIFY_CHANGE_SECURITY, IN_ATTRIB}
305};
306
307static uint32_t inotify_map(uint32_t *filter)
308{
309 int i;
310 uint32_t out=0;
311 for (i=0;i<ARRAY_SIZE(inotify_mapping);i++) {
312 if (inotify_mapping[i].notify_mask & *filter) {
313 out |= inotify_mapping[i].inotify_mask;
314 *filter &= ~inotify_mapping[i].notify_mask;
315 }
316 }
317 return out;
318}
319
320/*
321 destroy a watch
322*/
323static int watch_destructor(struct inotify_watch_context *w)
324{
325 struct inotify_private *in = w->in;
326 int wd = w->wd;
327 DLIST_REMOVE(w->in->watches, w);
328
329 for (w=in->watches;w;w=w->next) {
330 if (w->wd == wd) {
331 /*
332 * Another inotify_watch_context listens on this path,
333 * leave the kernel level watch in place
334 */
335 return 0;
336 }
337 }
338
339 DEBUG(10, ("Deleting inotify watch %d\n", wd));
340 if (inotify_rm_watch(in->fd, wd) == -1) {
341 DEBUG(1, ("inotify_rm_watch returned %s\n", strerror(errno)));
342 }
343 return 0;
344}
345
346
347/*
348 add a watch. The watch is removed when the caller calls
349 talloc_free() on *handle
350*/
351int inotify_watch(TALLOC_CTX *mem_ctx,
352 struct sys_notify_context *ctx,
353 const char *path,
354 uint32_t *filter,
355 uint32_t *subdir_filter,
356 void (*callback)(struct sys_notify_context *ctx,
357 void *private_data,
358 struct notify_event *ev),
359 void *private_data,
360 void *handle_p)
361{
362 struct inotify_private *in;
363 uint32_t mask;
364 struct inotify_watch_context *w;
365 uint32_t orig_filter = *filter;
366 void **handle = (void **)handle_p;
367
368 /* maybe setup the inotify fd */
369 if (ctx->private_data == NULL) {
370 int ret;
371 ret = inotify_setup(ctx);
372 if (ret != 0) {
373 return ret;
374 }
375 }
376
377 in = talloc_get_type(ctx->private_data, struct inotify_private);
378
379 mask = inotify_map(filter);
380 if (mask == 0) {
381 /* this filter can't be handled by inotify */
382 return EINVAL;
383 }
384
385 /* using IN_MASK_ADD allows us to cope with inotify() returning the same
386 watch descriptor for multiple watches on the same path */
387 mask |= (IN_MASK_ADD | IN_ONLYDIR);
388
389 w = talloc(mem_ctx, struct inotify_watch_context);
390 if (w == NULL) {
391 *filter = orig_filter;
392 return ENOMEM;
393 }
394
395 w->in = in;
396 w->callback = callback;
397 w->private_data = private_data;
398 w->mask = mask;
399 w->filter = orig_filter;
400 w->path = talloc_strdup(w, path);
401 if (w->path == NULL) {
402 *filter = orig_filter;
403 TALLOC_FREE(w);
404 return ENOMEM;
405 }
406
407 /* get a new watch descriptor for this path */
408 w->wd = inotify_add_watch(in->fd, path, mask);
409 if (w->wd == -1) {
410 int err = errno;
411 *filter = orig_filter;
412 TALLOC_FREE(w);
413 DEBUG(1, ("inotify_add_watch returned %s\n", strerror(err)));
414 return err;
415 }
416
417 DEBUG(10, ("inotify_add_watch for %s mask %x returned wd %d\n",
418 path, mask, w->wd));
419
420 (*handle) = w;
421
422 DLIST_ADD(in->watches, w);
423
424 /* the caller frees the handle to stop watching */
425 talloc_set_destructor(w, watch_destructor);
426
427 return 0;
428}
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