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