source/modules/vfs_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 2 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, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  20  */
  21
  22 #include "includes.h"
  23
  24 #include <fam.h>
  25
  26 #if !defined(HAVE_FAM_H_FAMCODES_TYPEDEF)
  27 /* Gamin provides this typedef which means we can't use 'enum FAMCodes' as per
  28  * every other FAM implementation. Phooey.
  29  */
  30 typedef enum FAMCodes FAMCodes;
  31 #endif
  32
  33 /* NOTE: There are multiple versions of FAM floating around the net, each with
  34  * slight differences from the original SGI FAM implementation. In this file,
  35  * we rely only on the SGI features and do not assume any extensions. For
  36  * example, we do not look at FAMErrno, because it is not set by the original
  37  * implementation.
  38  *
  39  * Random FAM links:
  40  *      http://oss.sgi.com/projects/fam/
  41  *      http://savannah.nongnu.org/projects/fam/
  42  *      http://sourceforge.net/projects/bsdfam/
  43  */
  44
  45 /* ------------------------------------------------------------------------- */
  46
  47 struct fam_watch_context {
  48         struct fam_watch_context *prev, *next;
  49         FAMConnection *fam_connection;
  50         struct FAMRequest fr;
  51         struct sys_notify_context *sys_ctx;
  52         void (*callback)(struct sys_notify_context *ctx,
  53                          void *private_data,
  54                          struct notify_event *ev);
  55         void *private_data;
  56         uint32_t mask; /* the inotify mask */
  57         uint32_t filter; /* the windows completion filter */
  58         const char *path;
  59 };
  60
  61
  62 /*
  63  * We want one FAM connection per smbd, not one per tcon.
  64  */
  65 static FAMConnection fam_connection;
  66 static BOOL fam_connection_initialized = False;
  67
  68 static struct fam_watch_context *fam_notify_list;
  69 static void fam_handler(struct event_context *event_ctx,
  70                         struct fd_event *fd_event,
  71                         uint16 flags,
  72                         void *private_data);
  73
  74 static NTSTATUS fam_open_connection(FAMConnection *fam_conn,
  75                                     struct event_context *event_ctx)
  76 {
  77         int res;
  78         char *name;
  79
  80         ZERO_STRUCTP(fam_conn);
  81         FAMCONNECTION_GETFD(fam_conn) = -1;
  82
  83         if (asprintf(&name, "smbd (%lu)", (unsigned long)sys_getpid()) == -1) {
  84                 DEBUG(0, ("No memory\n"));
  85                 return NT_STATUS_NO_MEMORY;
  86         }
  87
  88         res = FAMOpen2(fam_conn, name);
  89         SAFE_FREE(name);
  90
  91         if (res < 0) {
  92                 DEBUG(10, ("FAM file change notifications not available\n"));
  93                 /*
  94                  * No idea how to get NT_STATUS from a FAM result
  95                  */
  96                 FAMCONNECTION_GETFD(fam_conn) = -1;
  97                 return NT_STATUS_UNEXPECTED_IO_ERROR;
  98         }
  99
 100         if (event_add_fd(event_ctx, event_ctx,
 101                          FAMCONNECTION_GETFD(fam_conn),
 102                          EVENT_FD_READ, fam_handler,
 103                          (void *)fam_conn) == NULL) {
 104                 DEBUG(0, ("event_add_fd failed\n"));
 105                 FAMClose(fam_conn);
 106                 FAMCONNECTION_GETFD(fam_conn) = -1;
 107                 return NT_STATUS_NO_MEMORY;
 108         }
 109
 110         return NT_STATUS_OK;
 111 }
 112
 113 static void fam_reopen(FAMConnection *fam_conn,
 114                        struct event_context *event_ctx,
 115                        struct fam_watch_context *notify_list)
 116 {
 117         struct fam_watch_context *ctx;
 118
 119         DEBUG(5, ("Re-opening FAM connection\n"));
 120
 121         FAMClose(fam_conn);
 122
 123         if (!NT_STATUS_IS_OK(fam_open_connection(fam_conn, event_ctx))) {
 124                 DEBUG(5, ("Re-opening fam connection failed\n"));
 125                 return;
 126         }
 127
 128         for (ctx = notify_list; ctx; ctx = ctx->next) {
 129                 FAMMonitorDirectory(fam_conn, ctx->path, &ctx->fr, NULL);
 130         }
 131 }
 132
 133 static void fam_handler(struct event_context *event_ctx,
 134                         struct fd_event *fd_event,
 135                         uint16 flags,
 136                         void *private_data)
 137 {
 138         FAMConnection *fam_conn = (FAMConnection *)private_data;
 139         FAMEvent fam_event;
 140         struct fam_watch_context *ctx;
 141         struct notify_event ne;
 142
 143         if (FAMPending(fam_conn) == 0) {
 144                 DEBUG(10, ("fam_handler called but nothing pending\n"));
 145                 return;
 146         }
 147
 148         if (FAMNextEvent(fam_conn, &fam_event) != 1) {
 149                 DEBUG(5, ("FAMNextEvent returned an error\n"));
 150                 TALLOC_FREE(fd_event);
 151                 fam_reopen(fam_conn, event_ctx, fam_notify_list);
 152                 return;
 153         }
 154
 155         DEBUG(10, ("Got FAMCode %d for %s\n", fam_event.code,
 156                    fam_event.filename));
 157
 158         switch (fam_event.code) {
 159         case FAMChanged:
 160                 ne.action = NOTIFY_ACTION_MODIFIED;
 161                 break;
 162         case FAMCreated:
 163                 ne.action = NOTIFY_ACTION_ADDED;
 164                 break;
 165         case FAMDeleted:
 166                 ne.action = NOTIFY_ACTION_REMOVED;
 167                 break;
 168         default:
 169                 DEBUG(10, ("Ignoring code FAMCode %d for file %s\n",
 170                            (int)fam_event.code, fam_event.filename));
 171                 return;
 172         }
 173
 174         for (ctx = fam_notify_list; ctx; ctx = ctx->next) {
 175                 if (memcmp(&fam_event.fr, &ctx->fr, sizeof(FAMRequest)) == 0) {
 176                         break;
 177                 }
 178         }
 179
 180         if (ctx == NULL) {
 181                 DEBUG(5, ("Discarding event for file %s\n",
 182                           fam_event.filename));
 183                 return;
 184         }
 185
 186         if ((ne.path = strrchr_m(fam_event.filename, '\\')) == NULL) {
 187                 ne.path = fam_event.filename;
 188         }
 189
 190         ctx->callback(ctx->sys_ctx, ctx->private_data, &ne);
 191 }
 192
 193 static int fam_watch_context_destructor(struct fam_watch_context *ctx)
 194 {
 195         if (FAMCONNECTION_GETFD(ctx->fam_connection) != -1) {
 196                 FAMCancelMonitor(&fam_connection, &ctx->fr);
 197         }
 198         DLIST_REMOVE(fam_notify_list, ctx);
 199         return 0;
 200 }
 201
 202 /*
 203   add a watch. The watch is removed when the caller calls
 204   talloc_free() on *handle
 205 */
 206 static NTSTATUS fam_watch(vfs_handle_struct *vfs_handle,
 207                           struct sys_notify_context *ctx,
 208                           struct notify_entry *e,
 209                           void (*callback)(struct sys_notify_context *ctx,
 210                                            void *private_data,
 211                                            struct notify_event *ev),
 212                           void *private_data,
 213                           void *handle_p)
 214 {
 215         const uint32 fam_mask = (FILE_NOTIFY_CHANGE_FILE_NAME|
 216                                  FILE_NOTIFY_CHANGE_DIR_NAME);
 217         struct fam_watch_context *watch;
 218         void **handle = (void **)handle_p;
 219
 220         if ((e->filter & fam_mask) == 0) {
 221                 DEBUG(10, ("filter = %u, ignoring in FAM\n", e->filter));
 222                 return NT_STATUS_OK;
 223         }
 224
 225         if (!fam_connection_initialized) {
 226                 if (!NT_STATUS_IS_OK(fam_open_connection(&fam_connection,
 227                                                          ctx->ev))) {
 228                         /*
 229                          * Just let smbd do all the work itself
 230                          */
 231                         return NT_STATUS_OK;
 232                 }
 233                 fam_connection_initialized = True;
 234         }
 235
 236         if (!(watch = TALLOC_P(ctx, struct fam_watch_context))) {
 237                 return NT_STATUS_NO_MEMORY;
 238         }
 239
 240         watch->fam_connection = &fam_connection;
 241
 242         watch->callback = callback;
 243         watch->private_data = private_data;
 244         watch->sys_ctx = ctx;
 245
 246         if (!(watch->path = talloc_strdup(watch, e->path))) {
 247                 DEBUG(0, ("talloc_asprintf failed\n"));
 248                 TALLOC_FREE(watch);
 249                 return NT_STATUS_NO_MEMORY;
 250         }
 251
 252         /*
 253          * The FAM module in this early state will only take care of
 254          * FAMCreated and FAMDeleted events, Leave the rest to
 255          * notify_internal.c
 256          */
 257
 258         watch->filter = fam_mask;
 259         e->filter &= ~fam_mask;
 260
 261         DLIST_ADD(fam_notify_list, watch);
 262         talloc_set_destructor(watch, fam_watch_context_destructor);
 263
 264         /*
 265          * Only directories monitored so far
 266          */
 267
 268         if (FAMCONNECTION_GETFD(watch->fam_connection) != -1) {
 269                 FAMMonitorDirectory(watch->fam_connection, watch->path,
 270                                     &watch->fr, NULL);
 271         }
 272         else {
 273                 /*
 274                  * If the re-open is successful, this will establish the
 275                  * FAMMonitor from the list
 276                  */
 277                 fam_reopen(watch->fam_connection, ctx->ev, fam_notify_list);
 278         }
 279
 280         *handle = (void *)watch;
 281
 282         return NT_STATUS_OK;
 283 }
 284
 285 /* VFS operations structure */
 286
 287 static vfs_op_tuple notify_fam_op_tuples[] = {
 288
 289         {SMB_VFS_OP(fam_watch),
 290          SMB_VFS_OP_NOTIFY_WATCH,
 291          SMB_VFS_LAYER_OPAQUE},
 292
 293         {SMB_VFS_OP(NULL),
 294          SMB_VFS_OP_NOOP,
 295          SMB_VFS_LAYER_NOOP}
 296
 297 };
 298
 299
 300 NTSTATUS vfs_notify_fam_init(void);
 301 NTSTATUS vfs_notify_fam_init(void)
 302 {
 303         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "notify_fam",
 304                                 notify_fam_op_tuples);
 305 }