source3/smbd/notify_fam.c

   1 /*
   2  * FAM file notification support.
   3  *
   4  * Copyright (c) James Peach 2005
   5  * Copyright (c) Volker Lendecke 2007
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include "includes.h"
  22 #include "smbd/smbd.h"
  23 #include "librpc/gen_ndr/notify.h"
  24
  25 #include <fam.h>
  26
  27 #if !defined(HAVE_FAM_H_FAMCODES_TYPEDEF)
  28 /* Gamin provides this typedef which means we can't use 'enum FAMCodes' as per
  29  * every other FAM implementation. Phooey.
  30  */
  31 typedef enum FAMCodes FAMCodes;
  32 #endif
  33
  34 /* NOTE: There are multiple versions of FAM floating around the net, each with
  35  * slight differences from the original SGI FAM implementation. In this file,
  36  * we rely only on the SGI features and do not assume any extensions. For
  37  * example, we do not look at FAMErrno, because it is not set by the original
  38  * implementation.
  39  *
  40  * Random FAM links:
  41  *      http://oss.sgi.com/projects/fam/
  42  *      http://savannah.nongnu.org/projects/fam/
  43  *      http://sourceforge.net/projects/bsdfam/
  44  */
  45
  46 /* ------------------------------------------------------------------------- */
  47
  48 struct fam_watch_context {
  49         struct fam_watch_context *prev, *next;
  50         FAMConnection *fam_connection;
  51         struct FAMRequest fr;
  52         struct sys_notify_context *sys_ctx;
  53         void (*callback)(struct sys_notify_context *ctx,
  54                          void *private_data,
  55                          struct notify_event *ev);
  56         void *private_data;
  57         uint32_t mask; /* the inotify mask */
  58         uint32_t filter; /* the windows completion filter */
  59         const char *path;
  60 };
  61
  62
  63 /*
  64  * We want one FAM connection per smbd, not one per tcon.
  65  */
  66 static FAMConnection fam_connection;
  67 static bool fam_connection_initialized = False;
  68
  69 static struct fam_watch_context *fam_notify_list;
  70 static void fam_handler(struct tevent_context *event_ctx,
  71                         struct tevent_fd *fd_event,
  72                         uint16_t flags,
  73                         void *private_data);
  74
  75 static NTSTATUS fam_open_connection(FAMConnection *fam_conn,
  76                                     struct tevent_context *event_ctx)
  77 {
  78         int res;
  79         char *name;
  80
  81         ZERO_STRUCTP(fam_conn);
  82         FAMCONNECTION_GETFD(fam_conn) = -1;
  83
  84
  85 #ifdef HAVE_FAMNOEXISTS
  86         /* We should honor outside setting of the GAM_CLIENT_ID. */
  87         setenv("GAM_CLIENT_ID","SAMBA",0);
  88 #endif
  89
  90         if (asprintf(&name, "smbd (%lu)", (unsigned long)getpid()) == -1) {
  91                 DEBUG(0, ("No memory\n"));
  92                 return NT_STATUS_NO_MEMORY;
  93         }
  94
  95         res = FAMOpen2(fam_conn, name);
  96
  97 #ifdef HAVE_FAMNOEXISTS
  98         /*
  99          * This reduces the chatter between GAMIN and samba making the pair
 100          * much more reliable.
 101          */
 102         FAMNoExists(fam_conn);
 103 #endif
 104
 105         SAFE_FREE(name);
 106
 107         if (res < 0) {
 108                 DEBUG(10, ("FAM file change notifications not available: %s\n",
 109                            FamErrlist[-res]));
 110                 /*
 111                  * No idea how to get NT_STATUS from a FAM result
 112                  */
 113                 FAMCONNECTION_GETFD(fam_conn) = -1;
 114                 return NT_STATUS_UNEXPECTED_IO_ERROR;
 115         }
 116
 117         if (tevent_add_fd(event_ctx, event_ctx,
 118                          FAMCONNECTION_GETFD(fam_conn),
 119                          TEVENT_FD_READ, fam_handler,
 120                          (void *)fam_conn) == NULL) {
 121                 DEBUG(0, ("event_add_fd failed\n"));
 122                 FAMClose(fam_conn);
 123                 FAMCONNECTION_GETFD(fam_conn) = -1;
 124                 return NT_STATUS_NO_MEMORY;
 125         }
 126
 127         return NT_STATUS_OK;
 128 }
 129
 130 static void fam_reopen(FAMConnection *fam_conn,
 131                        struct tevent_context *event_ctx,
 132                        struct fam_watch_context *notify_list)
 133 {
 134         struct fam_watch_context *ctx;
 135
 136         DEBUG(5, ("Re-opening FAM connection\n"));
 137
 138         FAMClose(fam_conn);
 139
 140         if (!NT_STATUS_IS_OK(fam_open_connection(fam_conn, event_ctx))) {
 141                 DEBUG(5, ("Re-opening fam connection failed\n"));
 142                 return;
 143         }
 144
 145         for (ctx = notify_list; ctx; ctx = ctx->next) {
 146                 FAMMonitorDirectory(fam_conn, ctx->path, &ctx->fr, NULL);
 147         }
 148 }
 149
 150 static void fam_handler(struct tevent_context *event_ctx,
 151                         struct tevent_fd *fd_event,
 152                         uint16_t flags,
 153                         void *private_data)
 154 {
 155         FAMConnection *fam_conn = (FAMConnection *)private_data;
 156         FAMEvent fam_event;
 157         struct fam_watch_context *ctx;
 158         struct notify_event ne;
 159
 160         if (FAMPending(fam_conn) == 0) {
 161                 DEBUG(10, ("fam_handler called but nothing pending\n"));
 162                 return;
 163         }
 164
 165         if (FAMNextEvent(fam_conn, &fam_event) != 1) {
 166                 DEBUG(5, ("FAMNextEvent returned an error\n"));
 167                 TALLOC_FREE(fd_event);
 168                 fam_reopen(fam_conn, event_ctx, fam_notify_list);
 169                 return;
 170         }
 171
 172         DEBUG(10, ("Got FAMCode %d for %s\n", fam_event.code,
 173                    fam_event.filename));
 174
 175         switch (fam_event.code) {
 176         case FAMChanged:
 177                 ne.action = NOTIFY_ACTION_MODIFIED;
 178                 break;
 179         case FAMCreated:
 180                 ne.action = NOTIFY_ACTION_ADDED;
 181                 break;
 182         case FAMDeleted:
 183                 ne.action = NOTIFY_ACTION_REMOVED;
 184                 break;
 185         default:
 186                 DEBUG(10, ("Ignoring code FAMCode %d for file %s\n",
 187                            (int)fam_event.code, fam_event.filename));
 188                 return;
 189         }
 190
 191         for (ctx = fam_notify_list; ctx; ctx = ctx->next) {
 192                 if (memcmp(&fam_event.fr, &ctx->fr, sizeof(FAMRequest)) == 0) {
 193                         break;
 194                 }
 195         }
 196
 197         if (ctx == NULL) {
 198                 DEBUG(5, ("Discarding event for file %s\n",
 199                           fam_event.filename));
 200                 return;
 201         }
 202
 203         if ((ne.path = strrchr_m(fam_event.filename, '\\')) == NULL) {
 204                 ne.path = fam_event.filename;
 205         }
 206         ne.dir = ctx->path;
 207
 208         ctx->callback(ctx->sys_ctx, ctx->private_data, &ne);
 209 }
 210
 211 static int fam_watch_context_destructor(struct fam_watch_context *ctx)
 212 {
 213         if (FAMCONNECTION_GETFD(ctx->fam_connection) != -1) {
 214                 FAMCancelMonitor(&fam_connection, &ctx->fr);
 215         }
 216         DLIST_REMOVE(fam_notify_list, ctx);
 217         return 0;
 218 }
 219
 220 /*
 221   add a watch. The watch is removed when the caller calls
 222   talloc_free() on *handle
 223 */
 224 int _fam_watch(TALLOC_CTX *mem_ctx,
 225               struct sys_notify_context *ctx,
 226               const char *path,
 227               uint32_t *filter,
 228               uint32_t *subdir_filter,
 229               void (*callback)(struct sys_notify_context *ctx,
 230                                void *private_data,
 231                                struct notify_event *ev),
 232               void *private_data,
 233               void *handle_p)
 234 {
 235         const uint32_t fam_mask = (FILE_NOTIFY_CHANGE_FILE_NAME|
 236                                    FILE_NOTIFY_CHANGE_DIR_NAME);
 237         struct fam_watch_context *watch;
 238         void **handle = (void **)handle_p;
 239
 240         *handle = NULL;
 241
 242         if ((*filter & fam_mask) == 0) {
 243                 DEBUG(10, ("filter = %u, ignoring in FAM\n", *filter));
 244                 return 0;
 245         }
 246
 247         if (!fam_connection_initialized) {
 248                 if (!NT_STATUS_IS_OK(fam_open_connection(&fam_connection,
 249                                                          ctx->ev))) {
 250                         /*
 251                          * Just let smbd do all the work itself
 252                          */
 253                         return 0;
 254                 }
 255                 fam_connection_initialized = True;
 256         }
 257
 258         if (!(watch = talloc(mem_ctx, struct fam_watch_context))) {
 259                 return ENOMEM;
 260         }
 261
 262         watch->fam_connection = &fam_connection;
 263
 264         watch->callback = callback;
 265         watch->private_data = private_data;
 266         watch->sys_ctx = ctx;
 267
 268         watch->path = talloc_strdup(watch, path);
 269         if (watch->path == NULL) {
 270                 DEBUG(0, ("talloc_asprintf failed\n"));
 271                 TALLOC_FREE(watch);
 272                 return ENOMEM;
 273         }
 274
 275         /*
 276          * The FAM module in this early state will only take care of
 277          * FAMCreated and FAMDeleted events, Leave the rest to notifyd
 278          */
 279
 280         watch->filter = fam_mask;
 281         *filter &= ~fam_mask;
 282
 283         DLIST_ADD(fam_notify_list, watch);
 284         talloc_set_destructor(watch, fam_watch_context_destructor);
 285
 286         /*
 287          * Only directories monitored so far
 288          */
 289
 290         if (FAMCONNECTION_GETFD(watch->fam_connection) != -1) {
 291                 FAMMonitorDirectory(watch->fam_connection, watch->path,
 292                                     &watch->fr, NULL);
 293         }
 294         else {
 295                 /*
 296                  * If the re-open is successful, this will establish the
 297                  * FAMMonitor from the list
 298                  */
 299                 fam_reopen(watch->fam_connection, ctx->ev, fam_notify_list);
 300         }
 301
 302         *handle = watch;
 303
 304         return 0;
 305 }