source: trunk-3.0/source/smbd/notify_inotify.c@ 103

Last change on this file since 103 was 39, checked in by Paul Smedley, 18 years ago

Upgrade source to 3.0.25a
File size: 10.8 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 2 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, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19*/
20
21/*
22 notify implementation using inotify
23*/
24
25#include "includes.h"
26
27#ifdef HAVE_INOTIFY
28
29#ifdef HAVE_ASM_TYPES_H
30#include <asm/types.h>
31#endif
32
33#include <linux/inotify.h>
34#include <asm/unistd.h>
35
36#ifndef HAVE_INOTIFY_INIT
37/*
38 glibc doesn't define these functions yet (as of March 2006)
39*/
40static int inotify_init(void)
41{
42 return syscall(__NR_inotify_init);
43}
44
45static int inotify_add_watch(int fd, const char *path, __u32 mask)
46{
47 return syscall(__NR_inotify_add_watch, fd, path, mask);
48}
49
50static int inotify_rm_watch(int fd, int wd)
51{
52 return syscall(__NR_inotify_rm_watch, fd, wd);
53}
54#endif
55
56
57/* older glibc headers don't have these defines either */
58#ifndef IN_ONLYDIR
59#define IN_ONLYDIR 0x01000000
60#endif
61#ifndef IN_MASK_ADD
62#define IN_MASK_ADD 0x20000000
63#endif
64
65struct inotify_private {
66 struct sys_notify_context *ctx;
67 int fd;
68 struct inotify_watch_context *watches;
69};
70
71struct inotify_watch_context {
72 struct inotify_watch_context *next, *prev;
73 struct inotify_private *in;
74 int wd;
75 void (*callback)(struct sys_notify_context *ctx,
76 void *private_data,
77 struct notify_event *ev);
78 void *private_data;
79 uint32_t mask; /* the inotify mask */
80 uint32_t filter; /* the windows completion filter */
81 const char *path;
82};
83
84
85/*
86 destroy the inotify private context
87*/
88static int inotify_destructor(struct inotify_private *in)
89{
90 close(in->fd);
91 return 0;
92}
93
94
95/*
96 see if a particular event from inotify really does match a requested
97 notify event in SMB
98*/
99static BOOL filter_match(struct inotify_watch_context *w,
100 struct inotify_event *e)
101{
102 DEBUG(10, ("filter_match: e->mask=%x, w->mask=%x, w->filter=%x\n",
103 e->mask, w->mask, w->filter));
104
105 if ((e->mask & w->mask) == 0) {
106 /* this happens because inotify_add_watch() coalesces watches on the same
107 path, oring their masks together */
108 return False;
109 }
110
111 /* SMB separates the filters for files and directories */
112 if (e->mask & IN_ISDIR) {
113 if ((w->filter & FILE_NOTIFY_CHANGE_DIR_NAME) == 0) {
114 return False;
115 }
116 } else {
117 if ((e->mask & IN_ATTRIB) &&
118 (w->filter & (FILE_NOTIFY_CHANGE_ATTRIBUTES|
119 FILE_NOTIFY_CHANGE_LAST_WRITE|
120 FILE_NOTIFY_CHANGE_LAST_ACCESS|
121 FILE_NOTIFY_CHANGE_EA|
122 FILE_NOTIFY_CHANGE_SECURITY))) {
123 return True;
124 }
125 if ((e->mask & IN_MODIFY) &&
126 (w->filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)) {
127 return True;
128 }
129 if ((w->filter & FILE_NOTIFY_CHANGE_FILE_NAME) == 0) {
130 return False;
131 }
132 }
133
134 return True;
135}
136
137
138
139/*
140 dispatch one inotify event
141
142 the cookies are used to correctly handle renames
143*/
144static void inotify_dispatch(struct inotify_private *in,
145 struct inotify_event *e,
146 uint32_t prev_cookie,
147 struct inotify_event *e2)
148{
149 struct inotify_watch_context *w, *next;
150 struct notify_event ne;
151
152 DEBUG(10, ("inotify_dispatch called with mask=%x, name=[%s]\n",
153 e->mask, e->len ? e->name : ""));
154
155 /* ignore extraneous events, such as unmount and IN_IGNORED events */
156 if ((e->mask & (IN_ATTRIB|IN_MODIFY|IN_CREATE|IN_DELETE|
157 IN_MOVED_FROM|IN_MOVED_TO)) == 0) {
158 return;
159 }
160
161 /* map the inotify mask to a action. This gets complicated for
162 renames */
163 if (e->mask & IN_CREATE) {
164 ne.action = NOTIFY_ACTION_ADDED;
165 } else if (e->mask & IN_DELETE) {
166 ne.action = NOTIFY_ACTION_REMOVED;
167 } else if (e->mask & IN_MOVED_FROM) {
168 if (e2 != NULL && e2->cookie == e->cookie) {
169 ne.action = NOTIFY_ACTION_OLD_NAME;
170 } else {
171 ne.action = NOTIFY_ACTION_REMOVED;
172 }
173 } else if (e->mask & IN_MOVED_TO) {
174 if (e->cookie == prev_cookie) {
175 ne.action = NOTIFY_ACTION_NEW_NAME;
176 } else {
177 ne.action = NOTIFY_ACTION_ADDED;
178 }
179 } else {
180 ne.action = NOTIFY_ACTION_MODIFIED;
181 }
182 ne.path = e->name;
183
184 DEBUG(10, ("inotify_dispatch: ne.action = %d, ne.path = %s\n",
185 ne.action, ne.path));
186
187 /* find any watches that have this watch descriptor */
188 for (w=in->watches;w;w=next) {
189 next = w->next;
190 if (w->wd == e->wd && filter_match(w, e)) {
191 w->callback(in->ctx, w->private_data, &ne);
192 }
193 }
194
195 /* SMB expects a file rename to generate three events, two for
196 the rename and the other for a modify of the
197 destination. Strange! */
198 if (ne.action != NOTIFY_ACTION_NEW_NAME ||
199 (e->mask & IN_ISDIR) != 0) {
200 return;
201 }
202
203 ne.action = NOTIFY_ACTION_MODIFIED;
204 e->mask = IN_ATTRIB;
205
206 for (w=in->watches;w;w=next) {
207 next = w->next;
208 if (w->wd == e->wd && filter_match(w, e) &&
209 !(w->filter & FILE_NOTIFY_CHANGE_CREATION)) {
210 w->callback(in->ctx, w->private_data, &ne);
211 }
212 }
213}
214
215/*
216 called when the kernel has some events for us
217*/
218static void inotify_handler(struct event_context *ev, struct fd_event *fde,
219 uint16_t flags, void *private_data)
220{
221 struct inotify_private *in = talloc_get_type(private_data,
222 struct inotify_private);
223 int bufsize = 0;
224 struct inotify_event *e0, *e;
225 uint32_t prev_cookie=0;
226
227 /*
228 we must use FIONREAD as we cannot predict the length of the
229 filenames, and thus can't know how much to allocate
230 otherwise
231 */
232 if (ioctl(in->fd, FIONREAD, &bufsize) != 0 ||
233 bufsize == 0) {
234 DEBUG(0,("No data on inotify fd?!\n"));
235 return;
236 }
237
238 e0 = e = (struct inotify_event *)TALLOC_SIZE(in, bufsize);
239 if (e == NULL) return;
240
241 if (read(in->fd, e0, bufsize) != bufsize) {
242 DEBUG(0,("Failed to read all inotify data\n"));
243 talloc_free(e0);
244 return;
245 }
246
247 /* we can get more than one event in the buffer */
248 while (bufsize >= sizeof(*e)) {
249 struct inotify_event *e2 = NULL;
250 bufsize -= e->len + sizeof(*e);
251 if (bufsize >= sizeof(*e)) {
252 e2 = (struct inotify_event *)(e->len + sizeof(*e) + (char *)e);
253 }
254 inotify_dispatch(in, e, prev_cookie, e2);
255 prev_cookie = e->cookie;
256 e = e2;
257 }
258
259 talloc_free(e0);
260}
261
262/*
263 setup the inotify handle - called the first time a watch is added on
264 this context
265*/
266static NTSTATUS inotify_setup(struct sys_notify_context *ctx)
267{
268 struct inotify_private *in;
269
270 if (!lp_parm_bool(-1, "notify", "inotify", True)) {
271 return NT_STATUS_INVALID_SYSTEM_SERVICE;
272 }
273
274 in = talloc(ctx, struct inotify_private);
275 NT_STATUS_HAVE_NO_MEMORY(in);
276 in->fd = inotify_init();
277 if (in->fd == -1) {
278 DEBUG(0,("Failed to init inotify - %s\n", strerror(errno)));
279 talloc_free(in);
280 return map_nt_error_from_unix(errno);
281 }
282 in->ctx = ctx;
283 in->watches = NULL;
284
285 ctx->private_data = in;
286 talloc_set_destructor(in, inotify_destructor);
287
288 /* add a event waiting for the inotify fd to be readable */
289 event_add_fd(ctx->ev, in, in->fd, EVENT_FD_READ, inotify_handler, in);
290
291 return NT_STATUS_OK;
292}
293
294
295/*
296 map from a change notify mask to a inotify mask. Remove any bits
297 which we can handle
298*/
299static const struct {
300 uint32_t notify_mask;
301 uint32_t inotify_mask;
302} inotify_mapping[] = {
303 {FILE_NOTIFY_CHANGE_FILE_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
304 {FILE_NOTIFY_CHANGE_DIR_NAME, IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO},
305 {FILE_NOTIFY_CHANGE_ATTRIBUTES, IN_ATTRIB|IN_MOVED_TO|IN_MOVED_FROM|IN_MODIFY},
306 {FILE_NOTIFY_CHANGE_LAST_WRITE, IN_ATTRIB},
307 {FILE_NOTIFY_CHANGE_LAST_ACCESS, IN_ATTRIB},
308 {FILE_NOTIFY_CHANGE_EA, IN_ATTRIB},
309 {FILE_NOTIFY_CHANGE_SECURITY, IN_ATTRIB}
310};
311
312static uint32_t inotify_map(struct notify_entry *e)
313{
314 int i;
315 uint32_t out=0;
316 for (i=0;i<ARRAY_SIZE(inotify_mapping);i++) {
317 if (inotify_mapping[i].notify_mask & e->filter) {
318 out |= inotify_mapping[i].inotify_mask;
319 e->filter &= ~inotify_mapping[i].notify_mask;
320 }
321 }
322 return out;
323}
324
325/*
326 destroy a watch
327*/
328static int watch_destructor(struct inotify_watch_context *w)
329{
330 struct inotify_private *in = w->in;
331 int wd = w->wd;
332 DLIST_REMOVE(w->in->watches, w);
333
334 /* only rm the watch if its the last one with this wd */
335 for (w=in->watches;w;w=w->next) {
336 if (w->wd == wd) break;
337 }
338 if (w == NULL) {
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",
342 strerror(errno)));
343 }
344
345 }
346 return 0;
347}
348
349
350/*
351 add a watch. The watch is removed when the caller calls
352 talloc_free() on *handle
353*/
354NTSTATUS inotify_watch(struct sys_notify_context *ctx,
355 struct notify_entry *e,
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 int wd;
364 uint32_t mask;
365 struct inotify_watch_context *w;
366 uint32_t filter = e->filter;
367 void **handle = (void **)handle_p;
368
369 /* maybe setup the inotify fd */
370 if (ctx->private_data == NULL) {
371 NTSTATUS status;
372 status = inotify_setup(ctx);
373 NT_STATUS_NOT_OK_RETURN(status);
374 }
375
376 in = talloc_get_type(ctx->private_data, struct inotify_private);
377
378 mask = inotify_map(e);
379 if (mask == 0) {
380 /* this filter can't be handled by inotify */
381 return NT_STATUS_INVALID_PARAMETER;
382 }
383
384 /* using IN_MASK_ADD allows us to cope with inotify() returning the same
385 watch descriptor for muliple watches on the same path */
386 mask |= (IN_MASK_ADD | IN_ONLYDIR);
387
388 /* get a new watch descriptor for this path */
389 wd = inotify_add_watch(in->fd, e->path, mask);
390 if (wd == -1) {
391 e->filter = filter;
392 DEBUG(1, ("inotify_add_watch returned %s\n", strerror(errno)));
393 return map_nt_error_from_unix(errno);
394 }
395
396 DEBUG(10, ("inotify_add_watch for %s mask %x returned wd %d\n",
397 e->path, mask, wd));
398
399 w = talloc(in, struct inotify_watch_context);
400 if (w == NULL) {
401 inotify_rm_watch(in->fd, wd);
402 e->filter = filter;
403 return NT_STATUS_NO_MEMORY;
404 }
405
406 w->in = in;
407 w->wd = wd;
408 w->callback = callback;
409 w->private_data = private_data;
410 w->mask = mask;
411 w->filter = filter;
412 w->path = talloc_strdup(w, e->path);
413 if (w->path == NULL) {
414 inotify_rm_watch(in->fd, wd);
415 e->filter = filter;
416 return NT_STATUS_NO_MEMORY;
417 }
418
419 (*handle) = w;
420
421 DLIST_ADD(in->watches, w);
422
423 /* the caller frees the handle to stop watching */
424 talloc_set_destructor(w, watch_destructor);
425
426 return NT_STATUS_OK;
427}
428
429#endif
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