source3/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 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
  23 #include <fam.h>
  24
  25 #if !defined(HAVE_FAM_H_FAMCODES_TYPEDEF)
  26 /* Gamin provides this typedef which means we can't use 'enum FAMCodes' as per
  27  * every other FAM implementation. Phooey.
  28  */
  29 typedef enum FAMCodes FAMCodes;
  30 #endif
  31
  32 /* NOTE: There are multiple versions of FAM floating around the net, each with
  33  * slight differences from the original SGI FAM implementation. In this file,
  34  * we rely only on the SGI features and do not assume any extensions. For
  35  * example, we do not look at FAMErrno, because it is not set by the original
  36  * implementation.
  37  *
  38  * Random FAM links:
  39  *      http://oss.sgi.com/projects/fam/
  40  *      http://savannah.nongnu.org/projects/fam/
  41  *      http://sourceforge.net/projects/bsdfam/
  42  */
  43
  44 /* ------------------------------------------------------------------------- */
  45
  46 struct fam_watch_context {
  47         struct fam_watch_context *prev, *next;
  48         FAMConnection *fam_connection;
  49         struct FAMRequest fr;
  50         struct sys_notify_context *sys_ctx;
  51         void (*callback)(struct sys_notify_context *ctx,
  52                          void *private_data,
  53                          struct notify_event *ev);
  54         void *private_data;
  55         uint32_t mask; /* the inotify mask */
  56         uint32_t filter; /* the windows completion filter */
  57         const char *path;
  58 };
  59
  60
  61 /*
  62  * We want one FAM connection per smbd, not one per tcon.
  63  */
  64 static FAMConnection fam_connection;
  65 static bool fam_connection_initialized = False;
  66
  67 static struct fam_watch_context *fam_notify_list;
  68 static void fam_handler(struct event_context *event_ctx,
  69                         struct fd_event *fd_event,
  70                         uint16 flags,
  71                         void *private_data);
  72
  73 static NTSTATUS fam_open_connection(FAMConnection *fam_conn,
  74                                     struct event_context *event_ctx)
  75 {
  76         int res;
  77         char *name;
  78
  79         ZERO_STRUCTP(fam_conn);
  80         FAMCONNECTION_GETFD(fam_conn) = -1;
  81
  82
  83 #ifdef HAVE_FAMNOEXISTS
  84         /* We should honor outside setting of the GAM_CLIENT_ID. */
  85         setenv("GAM_CLIENT_ID","SAMBA",0);
  86 #endif
  87
  88         if (asprintf(&name, "smbd (%lu)", (unsigned long)sys_getpid()) == -1) {
  89                 DEBUG(0, ("No memory\n"));
  90                 return NT_STATUS_NO_MEMORY;
  91         }
  92
  93         res = FAMOpen2(fam_conn, name);
  94
  95 #ifdef HAVE_FAMNOEXISTS
  96         /*
  97          * This reduces the chatter between GAMIN and samba making the pair
  98          * much more reliable.
  99          */
 100         FAMNoExists(fam_conn);
 101 #endif
 102
 103         SAFE_FREE(name);
 104
 105         if (res < 0) {
 106                 DEBUG(10, ("FAM file change notifications not available\n"));
 107                 /*
 108                  * No idea how to get NT_STATUS from a FAM result
 109                  */
 110                 FAMCONNECTION_GETFD(fam_conn) = -1;
 111                 return NT_STATUS_UNEXPECTED_IO_ERROR;
 112         }
 113
 114         if (event_add_fd(event_ctx, event_ctx,
 115                          FAMCONNECTION_GETFD(fam_conn),
 116                          EVENT_FD_READ, fam_handler,
 117                          (void *)fam_conn) == NULL) {
 118                 DEBUG(0, ("event_add_fd failed\n"));
 119                 FAMClose(fam_conn);
 120                 FAMCONNECTION_GETFD(fam_conn) = -1;
 121                 return NT_STATUS_NO_MEMORY;
 122         }
 123
 124         return NT_STATUS_OK;
 125 }
 126
 127 static void fam_reopen(FAMConnection *fam_conn,
 128                        struct event_context *event_ctx,
 129                        struct fam_watch_context *notify_list)
 130 {
 131         struct fam_watch_context *ctx;
 132
 133         DEBUG(5, ("Re-opening FAM connection\n"));
 134
 135         FAMClose(fam_conn);
 136
 137         if (!NT_STATUS_IS_OK(fam_open_connection(fam_conn, event_ctx))) {
 138                 DEBUG(5, ("Re-opening fam connection failed\n"));
 139                 return;
 140         }
 141
 142         for (ctx = notify_list; ctx; ctx = ctx->next) {
 143                 FAMMonitorDirectory(fam_conn, ctx->path, &ctx->fr, NULL);
 144         }
 145 }
 146
 147 static void fam_handler(struct event_context *event_ctx,
 148                         struct fd_event *fd_event,
 149                         uint16 flags,
 150                         void *private_data)
 151 {
 152         FAMConnection *fam_conn = (FAMConnection *)private_data;
 153         FAMEvent fam_event;
 154         struct fam_watch_context *ctx;
 155         struct notify_event ne;
 156
 157         if (FAMPending(fam_conn) == 0) {
 158                 DEBUG(10, ("fam_handler called but nothing pending\n"));
 159                 return;
 160         }
 161
 162         if (FAMNextEvent(fam_conn, &fam_event) != 1) {
 163                 DEBUG(5, ("FAMNextEvent returned an error\n"));
 164                 TALLOC_FREE(fd_event);
 165                 fam_reopen(fam_conn, event_ctx, fam_notify_list);
 166                 return;
 167         }
 168
 169         DEBUG(10, ("Got FAMCode %d for %s\n", fam_event.code,
 170                    fam_event.filename));
 171
 172         switch (fam_event.code) {
 173         case FAMChanged:
 174                 ne.action = NOTIFY_ACTION_MODIFIED;
 175                 break;
 176         case FAMCreated:
 177                 ne.action = NOTIFY_ACTION_ADDED;
 178                 break;
 179         case FAMDeleted:
 180                 ne.action = NOTIFY_ACTION_REMOVED;
 181                 break;
 182         default:
 183                 DEBUG(10, ("Ignoring code FAMCode %d for file %s\n",
 184                            (int)fam_event.code, fam_event.filename));
 185                 return;
 186         }
 187
 188         for (ctx = fam_notify_list; ctx; ctx = ctx->next) {
 189                 if (memcmp(&fam_event.fr, &ctx->fr, sizeof(FAMRequest)) == 0) {
 190                         break;
 191                 }
 192         }
 193
 194         if (ctx == NULL) {
 195                 DEBUG(5, ("Discarding event for file %s\n",
 196                           fam_event.filename));
 197                 return;
 198         }
 199
 200         if ((ne.path = strrchr_m(fam_event.filename, '\\')) == NULL) {
 201                 ne.path = fam_event.filename;
 202         }
 203
 204         ctx->callback(ctx->sys_ctx, ctx->private_data, &ne);
 205 }
 206
 207 static int fam_watch_context_destructor(struct fam_watch_context *ctx)
 208 {
 209         if (FAMCONNECTION_GETFD(ctx->fam_connection) != -1) {
 210                 FAMCancelMonitor(&fam_connection, &ctx->fr);
 211         }
 212         DLIST_REMOVE(fam_notify_list, ctx);
 213         return 0;
 214 }
 215
 216 /*
 217   add a watch. The watch is removed when the caller calls
 218   talloc_free() on *handle
 219 */
 220 static NTSTATUS fam_watch(vfs_handle_struct *vfs_handle,
 221                           struct sys_notify_context *ctx,
 222                           struct notify_entry *e,
 223                           void (*callback)(struct sys_notify_context *ctx,
 224                                            void *private_data,
 225                                            struct notify_event *ev),
 226                           void *private_data,
 227                           void *handle_p)
 228 {
 229         const uint32 fam_mask = (FILE_NOTIFY_CHANGE_FILE_NAME|
 230                                  FILE_NOTIFY_CHANGE_DIR_NAME);
 231         struct fam_watch_context *watch;
 232         void **handle = (void **)handle_p;
 233
 234         if ((e->filter & fam_mask) == 0) {
 235                 DEBUG(10, ("filter = %u, ignoring in FAM\n", e->filter));
 236                 return NT_STATUS_OK;
 237         }
 238
 239         if (!fam_connection_initialized) {
 240                 if (!NT_STATUS_IS_OK(fam_open_connection(&fam_connection,
 241                                                          ctx->ev))) {
 242                         /*
 243                          * Just let smbd do all the work itself
 244                          */
 245                         return NT_STATUS_OK;
 246                 }
 247                 fam_connection_initialized = True;
 248         }
 249
 250         if (!(watch = TALLOC_P(ctx, struct fam_watch_context))) {
 251                 return NT_STATUS_NO_MEMORY;
 252         }
 253
 254         watch->fam_connection = &fam_connection;
 255
 256         watch->callback = callback;
 257         watch->private_data = private_data;
 258         watch->sys_ctx = ctx;
 259
 260         if (!(watch->path = talloc_strdup(watch, e->path))) {
 261                 DEBUG(0, ("talloc_asprintf failed\n"));
 262                 TALLOC_FREE(watch);
 263                 return NT_STATUS_NO_MEMORY;
 264         }
 265
 266         /*
 267          * The FAM module in this early state will only take care of
 268          * FAMCreated and FAMDeleted events, Leave the rest to
 269          * notify_internal.c
 270          */
 271
 272         watch->filter = fam_mask;
 273         e->filter &= ~fam_mask;
 274
 275         DLIST_ADD(fam_notify_list, watch);
 276         talloc_set_destructor(watch, fam_watch_context_destructor);
 277
 278         /*
 279          * Only directories monitored so far
 280          */
 281
 282         if (FAMCONNECTION_GETFD(watch->fam_connection) != -1) {
 283                 FAMMonitorDirectory(watch->fam_connection, watch->path,
 284                                     &watch->fr, NULL);
 285         }
 286         else {
 287                 /*
 288                  * If the re-open is successful, this will establish the
 289                  * FAMMonitor from the list
 290                  */
 291                 fam_reopen(watch->fam_connection, ctx->ev, fam_notify_list);
 292         }
 293
 294         *handle = (void *)watch;
 295
 296         return NT_STATUS_OK;
 297 }
 298
 299 /* VFS operations structure */
 300
 301 static struct vfs_fn_pointers notify_fam_fns = {
 302         .notify_watch = fam_watch,
 303 };
 304
 305
 306 NTSTATUS vfs_notify_fam_init(void);
 307 NTSTATUS vfs_notify_fam_init(void)
 308 {
 309         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "notify_fam",
 310                                 &notify_fam_fns);
 311 }