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      1 /* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 2; tab-width: 8 -*- */
      2 
      3 /* inotify-path.c - GVFS Directory Monitor based on inotify.
      4 
      5    Copyright (C) 2006 John McCutchan
      6 
      7    The Gnome Library is free software; you can redistribute it and/or
      8    modify it under the terms of the GNU Library General Public License as
      9    published by the Free Software Foundation; either version 2 of the
     10    License, or (at your option) any later version.
     11 
     12    The Gnome Library 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 GNU
     15    Library General Public License for more details.
     16 
     17    You should have received a copy of the GNU Library General Public
     18    License along with the Gnome Library; see the file COPYING.LIB.  If not,
     19    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     20    Boston, MA 02111-1307, USA.
     21 
     22    Authors:
     23 		 John McCutchan <john (at) johnmccutchan.com>
     24 */
     25 
     26 #include "config.h"
     27 
     28 /* Don't put conflicting kernel types in the global namespace: */
     29 #define __KERNEL_STRICT_NAMES
     30 
     31 #include <sys/inotify.h>
     32 #include <string.h>
     33 #include <glib.h>
     34 #include "inotify-kernel.h"
     35 #include "inotify-path.h"
     36 #include "inotify-missing.h"
     37 
     38 #define IP_INOTIFY_MASK (IN_MODIFY|IN_ATTRIB|IN_MOVED_FROM|IN_MOVED_TO|IN_DELETE|IN_CREATE|IN_DELETE_SELF|IN_UNMOUNT|IN_MOVE_SELF|IN_CLOSE_WRITE)
     39 
     40 /* Older libcs don't have this */
     41 #ifndef IN_ONLYDIR
     42 #define IN_ONLYDIR 0
     43 #endif
     44 
     45 typedef struct ip_watched_dir_s {
     46   char *path;
     47   /* TODO: We need to maintain a tree of watched directories
     48    * so that we can deliver move/delete events to sub folders.
     49    * Or the application could do it...
     50    */
     51   struct ip_watched_dir_s* parent;
     52   GList*	 children;
     53 
     54   /* Inotify state */
     55   gint32 wd;
     56 
     57   /* List of inotify subscriptions */
     58   GList *subs;
     59 } ip_watched_dir_t;
     60 
     61 static gboolean     ip_debug_enabled = FALSE;
     62 #define IP_W if (ip_debug_enabled) g_warning
     63 
     64 /* path -> ip_watched_dir */
     65 static GHashTable * path_dir_hash = NULL;
     66 /* inotify_sub * -> ip_watched_dir *
     67  *
     68  * Each subscription is attached to a watched directory or it is on
     69  * the missing list
     70  */
     71 static GHashTable * sub_dir_hash = NULL;
     72 /* This hash holds GLists of ip_watched_dir_t *'s
     73  * We need to hold a list because symbolic links can share
     74  * the same wd
     75  */
     76 static GHashTable * wd_dir_hash = NULL;
     77 
     78 static ip_watched_dir_t *ip_watched_dir_new  (const char       *path,
     79 					      int               wd);
     80 static void              ip_watched_dir_free (ip_watched_dir_t *dir);
     81 static void              ip_event_callback   (ik_event_t       *event);
     82 
     83 
     84 static void (*event_callback)(ik_event_t *event, inotify_sub *sub);
     85 
     86 gboolean
     87 _ip_startup (void (*cb)(ik_event_t *event, inotify_sub *sub))
     88 {
     89   static gboolean initialized = FALSE;
     90   static gboolean result = FALSE;
     91 
     92   if (initialized == TRUE)
     93     return result;
     94 
     95   event_callback = cb;
     96   result = _ik_startup (ip_event_callback);
     97 
     98   if (!result)
     99     return FALSE;
    100 
    101   path_dir_hash = g_hash_table_new (g_str_hash, g_str_equal);
    102   sub_dir_hash = g_hash_table_new (g_direct_hash, g_direct_equal);
    103   wd_dir_hash = g_hash_table_new (g_direct_hash, g_direct_equal);
    104 
    105   initialized = TRUE;
    106   return TRUE;
    107 }
    108 
    109 static void
    110 ip_map_path_dir (const char       *path,
    111                  ip_watched_dir_t *dir)
    112 {
    113   g_assert (path && dir);
    114   g_hash_table_insert (path_dir_hash, dir->path, dir);
    115 }
    116 
    117 static void
    118 ip_map_sub_dir (inotify_sub      *sub,
    119                 ip_watched_dir_t *dir)
    120 {
    121   /* Associate subscription and directory */
    122   g_assert (dir && sub);
    123   g_hash_table_insert (sub_dir_hash, sub, dir);
    124   dir->subs = g_list_prepend (dir->subs, sub);
    125 }
    126 
    127 static void
    128 ip_map_wd_dir (gint32            wd,
    129                ip_watched_dir_t *dir)
    130 {
    131   GList *dir_list;
    132 
    133   g_assert (wd >= 0 && dir);
    134   dir_list = g_hash_table_lookup (wd_dir_hash, GINT_TO_POINTER (wd));
    135   dir_list = g_list_prepend (dir_list, dir);
    136   g_hash_table_replace (wd_dir_hash, GINT_TO_POINTER (dir->wd), dir_list);
    137 }
    138 
    139 gboolean
    140 _ip_start_watching (inotify_sub *sub)
    141 {
    142   gint32 wd;
    143   int err;
    144   ip_watched_dir_t *dir;
    145 
    146   g_assert (sub);
    147   g_assert (!sub->cancelled);
    148   g_assert (sub->dirname);
    149 
    150   IP_W ("Starting to watch %s\n", sub->dirname);
    151   dir = g_hash_table_lookup (path_dir_hash, sub->dirname);
    152   if (dir)
    153     {
    154       IP_W ("Already watching\n");
    155       goto out;
    156     }
    157 
    158   IP_W ("Trying to add inotify watch ");
    159   wd = _ik_watch (sub->dirname, IP_INOTIFY_MASK|IN_ONLYDIR, &err);
    160   if (wd < 0)
    161     {
    162       IP_W ("Failed\n");
    163       return FALSE;
    164     }
    165   else
    166     {
    167       /* Create new watched directory and associate it with the
    168        * wd hash and path hash
    169        */
    170       IP_W ("Success\n");
    171       dir = ip_watched_dir_new (sub->dirname, wd);
    172       ip_map_wd_dir (wd, dir);
    173       ip_map_path_dir (sub->dirname, dir);
    174     }
    175 
    176  out:
    177   ip_map_sub_dir (sub, dir);
    178 
    179   return TRUE;
    180 }
    181 
    182 static void
    183 ip_unmap_path_dir (const char       *path,
    184                    ip_watched_dir_t *dir)
    185 {
    186   g_assert (path && dir);
    187   g_hash_table_remove (path_dir_hash, dir->path);
    188 }
    189 
    190 static void
    191 ip_unmap_wd_dir (gint32            wd,
    192                  ip_watched_dir_t *dir)
    193 {
    194   GList *dir_list = g_hash_table_lookup (wd_dir_hash, GINT_TO_POINTER (wd));
    195 
    196   if (!dir_list)
    197     return;
    198 
    199   g_assert (wd >= 0 && dir);
    200   dir_list = g_list_remove (dir_list, dir);
    201   if (dir_list == NULL)
    202     g_hash_table_remove (wd_dir_hash, GINT_TO_POINTER (dir->wd));
    203   else
    204     g_hash_table_replace (wd_dir_hash, GINT_TO_POINTER (dir->wd), dir_list);
    205 }
    206 
    207 static void
    208 ip_unmap_wd (gint32 wd)
    209 {
    210   GList *dir_list = g_hash_table_lookup (wd_dir_hash, GINT_TO_POINTER (wd));
    211   if (!dir_list)
    212     return;
    213   g_assert (wd >= 0);
    214   g_hash_table_remove (wd_dir_hash, GINT_TO_POINTER (wd));
    215   g_list_free (dir_list);
    216 }
    217 
    218 static void
    219 ip_unmap_sub_dir (inotify_sub       *sub,
    220                   ip_watched_dir_t *dir)
    221 {
    222   g_assert (sub && dir);
    223   g_hash_table_remove (sub_dir_hash, sub);
    224   dir->subs = g_list_remove (dir->subs, sub);
    225 }
    226 
    227 static void
    228 ip_unmap_all_subs (ip_watched_dir_t *dir)
    229 {
    230   GList *l = NULL;
    231 
    232   for (l = dir->subs; l; l = l->next)
    233     {
    234       inotify_sub *sub = l->data;
    235       g_hash_table_remove (sub_dir_hash, sub);
    236     }
    237   g_list_free (dir->subs);
    238   dir->subs = NULL;
    239 }
    240 
    241 gboolean
    242 _ip_stop_watching (inotify_sub *sub)
    243 {
    244   ip_watched_dir_t *dir = NULL;
    245 
    246   dir = g_hash_table_lookup (sub_dir_hash, sub);
    247   if (!dir)
    248     return TRUE;
    249 
    250   ip_unmap_sub_dir (sub, dir);
    251 
    252   /* No one is subscribing to this directory any more */
    253   if (dir->subs == NULL)
    254     {
    255       _ik_ignore (dir->path, dir->wd);
    256       ip_unmap_wd_dir (dir->wd, dir);
    257       ip_unmap_path_dir (dir->path, dir);
    258       ip_watched_dir_free (dir);
    259     }
    260 
    261   return TRUE;
    262 }
    263 
    264 
    265 static ip_watched_dir_t *
    266 ip_watched_dir_new (const char *path,
    267                     gint32      wd)
    268 {
    269   ip_watched_dir_t *dir = g_new0 (ip_watched_dir_t, 1);
    270 
    271   dir->path = g_strdup (path);
    272   dir->wd = wd;
    273 
    274   return dir;
    275 }
    276 
    277 static void
    278 ip_watched_dir_free (ip_watched_dir_t *dir)
    279 {
    280   g_assert (dir->subs == NULL);
    281   g_free (dir->path);
    282   g_free (dir);
    283 }
    284 
    285 static void
    286 ip_wd_delete (gpointer data,
    287               gpointer user_data)
    288 {
    289   ip_watched_dir_t *dir = data;
    290   GList *l = NULL;
    291 
    292   for (l = dir->subs; l; l = l->next)
    293     {
    294       inotify_sub *sub = l->data;
    295       /* Add subscription to missing list */
    296       _im_add (sub);
    297     }
    298   ip_unmap_all_subs (dir);
    299   /* Unassociate the path and the directory */
    300   ip_unmap_path_dir (dir->path, dir);
    301   ip_watched_dir_free (dir);
    302 }
    303 
    304 static void
    305 ip_event_dispatch (GList      *dir_list,
    306                    GList      *pair_dir_list,
    307                    ik_event_t *event)
    308 {
    309   GList *dirl;
    310 
    311   if (!event)
    312     return;
    313 
    314   for (dirl = dir_list; dirl; dirl = dirl->next)
    315     {
    316       GList *subl;
    317       ip_watched_dir_t *dir = dirl->data;
    318 
    319       for (subl = dir->subs; subl; subl = subl->next)
    320 	{
    321 	  inotify_sub *sub = subl->data;
    322 
    323 	  /* If the subscription and the event
    324 	   * contain a filename and they don't
    325 	   * match, we don't deliver this event.
    326 	   */
    327 	  if (sub->filename &&
    328 	      event->name &&
    329 	      strcmp (sub->filename, event->name))
    330 	    continue;
    331 
    332 	  /* If the subscription has a filename
    333 	   * but this event doesn't, we don't
    334 	   * deliever this event.
    335 	   */
    336 	  if (sub->filename && !event->name)
    337 	    continue;
    338 
    339 	  /* FIXME: We might need to synthesize
    340 	   * DELETE/UNMOUNT events when
    341 	   * the filename doesn't match
    342 	   */
    343 
    344 	  event_callback (event, sub);
    345 	}
    346     }
    347 
    348   if (!event->pair)
    349     return;
    350 
    351   for (dirl = pair_dir_list; dirl; dirl = dirl->next)
    352     {
    353       GList *subl;
    354       ip_watched_dir_t *dir = dirl->data;
    355 
    356       for (subl = dir->subs; subl; subl = subl->next)
    357 	{
    358 	  inotify_sub *sub = subl->data;
    359 
    360 	  /* If the subscription and the event
    361 	   * contain a filename and they don't
    362 	   * match, we don't deliver this event.
    363 	   */
    364 	  if (sub->filename &&
    365 	      event->pair->name &&
    366 	      strcmp (sub->filename, event->pair->name))
    367 	    continue;
    368 
    369 	  /* If the subscription has a filename
    370 	   * but this event doesn't, we don't
    371 	   * deliever this event.
    372 	   */
    373 	  if (sub->filename && !event->pair->name)
    374 	    continue;
    375 
    376 	  /* FIXME: We might need to synthesize
    377 	   * DELETE/UNMOUNT events when
    378 	   * the filename doesn't match
    379 	   */
    380 
    381 	  event_callback (event->pair, sub);
    382 	}
    383     }
    384 }
    385 
    386 static void
    387 ip_event_callback (ik_event_t *event)
    388 {
    389   GList* dir_list = NULL;
    390   GList* pair_dir_list = NULL;
    391 
    392   dir_list = g_hash_table_lookup (wd_dir_hash, GINT_TO_POINTER (event->wd));
    393 
    394   /* We can ignore the IGNORED events */
    395   if (event->mask & IN_IGNORED)
    396     {
    397       _ik_event_free (event);
    398       return;
    399     }
    400 
    401   if (event->pair)
    402     pair_dir_list = g_hash_table_lookup (wd_dir_hash, GINT_TO_POINTER (event->pair->wd));
    403 
    404   if (event->mask & IP_INOTIFY_MASK)
    405     ip_event_dispatch (dir_list, pair_dir_list, event);
    406 
    407   /* We have to manage the missing list
    408    * when we get an event that means the
    409    * file has been deleted/moved/unmounted.
    410    */
    411   if (event->mask & IN_DELETE_SELF ||
    412       event->mask & IN_MOVE_SELF ||
    413       event->mask & IN_UNMOUNT)
    414     {
    415       /* Add all subscriptions to missing list */
    416       g_list_foreach (dir_list, ip_wd_delete, NULL);
    417       /* Unmap all directories attached to this wd */
    418       ip_unmap_wd (event->wd);
    419     }
    420 
    421   _ik_event_free (event);
    422 }
    423