glib/gio/inotify/inotify-path.c
Ryan Lortie 707bc4a40f gio + inotify support for hard links
Add a new GFileMonitorFlag: G_FILE_MONITOR_WATCH_HARD_LINKS.  When set,
changes made to the file via another hard link will be detected.

Implement the new flag for the inotify backend.

https://bugzilla.gnome.org/show_bug.cgi?id=532815
2012-12-19 08:19:18 -05:00

664 lines
16 KiB
C

/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 2; tab-width: 8 -*- */
/* inotify-path.c - GVFS Directory Monitor based on inotify.
Copyright (C) 2006 John McCutchan
Copyright (C) 2009 Codethink Limited
The Gnome Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The Gnome Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the Gnome Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
Authors:
John McCutchan <john@johnmccutchan.com>
Ryan Lortie <desrt@desrt.ca>
*/
#include "config.h"
/* Don't put conflicting kernel types in the global namespace: */
#define __KERNEL_STRICT_NAMES
#include <sys/inotify.h>
#include <string.h>
#include <glib.h>
#include "inotify-kernel.h"
#include "inotify-path.h"
#include "inotify-missing.h"
#define IP_INOTIFY_DIR_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)
#define IP_INOTIFY_FILE_MASK (IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE)
/* Older libcs don't have this */
#ifndef IN_ONLYDIR
#define IN_ONLYDIR 0
#endif
typedef struct ip_watched_file_s {
gchar *filename;
gchar *path;
gint32 wd;
GList *subs;
} ip_watched_file_t;
typedef struct ip_watched_dir_s {
char *path;
/* TODO: We need to maintain a tree of watched directories
* so that we can deliver move/delete events to sub folders.
* Or the application could do it...
*/
struct ip_watched_dir_s* parent;
GList* children;
/* basename -> ip_watched_file_t
* Maps basename to a ip_watched_file_t if the file is currently
* being directly watched for changes (ie: 'hardlinks' mode).
*/
GHashTable *files_hash;
/* Inotify state */
gint32 wd;
/* List of inotify subscriptions */
GList *subs;
} ip_watched_dir_t;
static gboolean ip_debug_enabled = FALSE;
#define IP_W if (ip_debug_enabled) g_warning
/* path -> ip_watched_dir */
static GHashTable * path_dir_hash = NULL;
/* inotify_sub * -> ip_watched_dir *
*
* Each subscription is attached to a watched directory or it is on
* the missing list
*/
static GHashTable * sub_dir_hash = NULL;
/* This hash holds GLists of ip_watched_dir_t *'s
* We need to hold a list because symbolic links can share
* the same wd
*/
static GHashTable * wd_dir_hash = NULL;
/* This hash holds GLists of ip_watched_file_t *'s
* We need to hold a list because links can share
* the same wd
*/
static GHashTable * wd_file_hash = NULL;
static ip_watched_dir_t *ip_watched_dir_new (const char *path,
int wd);
static void ip_watched_dir_free (ip_watched_dir_t *dir);
static void ip_event_callback (ik_event_t *event);
static void (*event_callback)(ik_event_t *event, inotify_sub *sub, gboolean file_event);
gboolean
_ip_startup (void (*cb)(ik_event_t *event, inotify_sub *sub, gboolean file_event))
{
static gboolean initialized = FALSE;
static gboolean result = FALSE;
if (initialized == TRUE)
return result;
event_callback = cb;
result = _ik_startup (ip_event_callback);
if (!result)
return FALSE;
path_dir_hash = g_hash_table_new (g_str_hash, g_str_equal);
sub_dir_hash = g_hash_table_new (g_direct_hash, g_direct_equal);
wd_dir_hash = g_hash_table_new (g_direct_hash, g_direct_equal);
wd_file_hash = g_hash_table_new (g_direct_hash, g_direct_equal);
initialized = TRUE;
return TRUE;
}
static void
ip_map_path_dir (const char *path,
ip_watched_dir_t *dir)
{
g_assert (path && dir);
g_hash_table_insert (path_dir_hash, dir->path, dir);
}
static void
ip_map_sub_dir (inotify_sub *sub,
ip_watched_dir_t *dir)
{
/* Associate subscription and directory */
g_assert (dir && sub);
g_hash_table_insert (sub_dir_hash, sub, dir);
dir->subs = g_list_prepend (dir->subs, sub);
}
static void
ip_map_wd_dir (gint32 wd,
ip_watched_dir_t *dir)
{
GList *dir_list;
g_assert (wd >= 0 && dir);
dir_list = g_hash_table_lookup (wd_dir_hash, GINT_TO_POINTER (wd));
dir_list = g_list_prepend (dir_list, dir);
g_hash_table_replace (wd_dir_hash, GINT_TO_POINTER (dir->wd), dir_list);
}
static void
ip_map_wd_file (gint32 wd,
ip_watched_file_t *file)
{
GList *file_list;
g_assert (wd >= 0 && file);
file_list = g_hash_table_lookup (wd_file_hash, GINT_TO_POINTER (wd));
file_list = g_list_prepend (file_list, file);
g_hash_table_replace (wd_file_hash, GINT_TO_POINTER (wd), file_list);
}
static void
ip_unmap_wd_file (gint32 wd,
ip_watched_file_t *file)
{
GList *file_list = g_hash_table_lookup (wd_file_hash, GINT_TO_POINTER (wd));
if (!file_list)
return;
g_assert (wd >= 0 && file);
file_list = g_list_remove (file_list, file);
if (file_list == NULL)
g_hash_table_remove (wd_file_hash, GINT_TO_POINTER (wd));
else
g_hash_table_replace (wd_file_hash, GINT_TO_POINTER (wd), file_list);
}
static ip_watched_file_t *
ip_watched_file_new (const gchar *dirname,
const gchar *filename)
{
ip_watched_file_t *file;
file = g_new0 (ip_watched_file_t, 1);
file->path = g_strjoin ("/", dirname, filename, NULL);
file->filename = g_strdup (filename);
file->wd = -1;
return file;
}
static void
ip_watched_file_free (ip_watched_file_t *file)
{
g_assert (file->subs == NULL);
g_free (file->filename);
g_free (file->path);
}
static void
ip_watched_file_add_sub (ip_watched_file_t *file,
inotify_sub *sub)
{
file->subs = g_list_prepend (file->subs, sub);
}
static void
ip_watched_file_start (ip_watched_file_t *file)
{
if (file->wd < 0)
{
gint err;
file->wd = _ik_watch (file->path,
IP_INOTIFY_FILE_MASK,
&err);
if (file->wd >= 0)
ip_map_wd_file (file->wd, file);
}
}
static void
ip_watched_file_stop (ip_watched_file_t *file)
{
if (file->wd >= 0)
{
_ik_ignore (file->path, file->wd);
ip_unmap_wd_file (file->wd, file);
file->wd = -1;
}
}
gboolean
_ip_start_watching (inotify_sub *sub)
{
gint32 wd;
int err;
ip_watched_dir_t *dir;
g_assert (sub);
g_assert (!sub->cancelled);
g_assert (sub->dirname);
IP_W ("Starting to watch %s\n", sub->dirname);
dir = g_hash_table_lookup (path_dir_hash, sub->dirname);
if (dir == NULL)
{
IP_W ("Trying to add inotify watch ");
wd = _ik_watch (sub->dirname, IP_INOTIFY_DIR_MASK|IN_ONLYDIR, &err);
if (wd < 0)
{
IP_W ("Failed\n");
return FALSE;
}
else
{
/* Create new watched directory and associate it with the
* wd hash and path hash
*/
IP_W ("Success\n");
dir = ip_watched_dir_new (sub->dirname, wd);
ip_map_wd_dir (wd, dir);
ip_map_path_dir (sub->dirname, dir);
}
}
else
IP_W ("Already watching\n");
if (sub->hardlinks)
{
ip_watched_file_t *file;
file = g_hash_table_lookup (dir->files_hash, sub->filename);
if (file == NULL)
{
file = ip_watched_file_new (sub->dirname, sub->filename);
g_hash_table_insert (dir->files_hash, file->filename, file);
}
ip_watched_file_add_sub (file, sub);
ip_watched_file_start (file);
}
ip_map_sub_dir (sub, dir);
return TRUE;
}
static void
ip_unmap_path_dir (const char *path,
ip_watched_dir_t *dir)
{
g_assert (path && dir);
g_hash_table_remove (path_dir_hash, dir->path);
}
static void
ip_unmap_wd_dir (gint32 wd,
ip_watched_dir_t *dir)
{
GList *dir_list = g_hash_table_lookup (wd_dir_hash, GINT_TO_POINTER (wd));
if (!dir_list)
return;
g_assert (wd >= 0 && dir);
dir_list = g_list_remove (dir_list, dir);
if (dir_list == NULL)
g_hash_table_remove (wd_dir_hash, GINT_TO_POINTER (dir->wd));
else
g_hash_table_replace (wd_dir_hash, GINT_TO_POINTER (dir->wd), dir_list);
}
static void
ip_unmap_wd (gint32 wd)
{
GList *dir_list = g_hash_table_lookup (wd_dir_hash, GINT_TO_POINTER (wd));
if (!dir_list)
return;
g_assert (wd >= 0);
g_hash_table_remove (wd_dir_hash, GINT_TO_POINTER (wd));
g_list_free (dir_list);
}
static void
ip_unmap_sub_dir (inotify_sub *sub,
ip_watched_dir_t *dir)
{
g_assert (sub && dir);
g_hash_table_remove (sub_dir_hash, sub);
dir->subs = g_list_remove (dir->subs, sub);
if (sub->hardlinks)
{
ip_watched_file_t *file;
file = g_hash_table_lookup (dir->files_hash, sub->filename);
file->subs = g_list_remove (file->subs, sub);
if (file->subs == NULL)
{
g_hash_table_remove (dir->files_hash, sub->filename);
ip_watched_file_stop (file);
ip_watched_file_free (file);
}
}
}
static void
ip_unmap_all_subs (ip_watched_dir_t *dir)
{
while (dir->subs != NULL)
ip_unmap_sub_dir (dir->subs->data, dir);
}
gboolean
_ip_stop_watching (inotify_sub *sub)
{
ip_watched_dir_t *dir = NULL;
dir = g_hash_table_lookup (sub_dir_hash, sub);
if (!dir)
return TRUE;
ip_unmap_sub_dir (sub, dir);
/* No one is subscribing to this directory any more */
if (dir->subs == NULL)
{
_ik_ignore (dir->path, dir->wd);
ip_unmap_wd_dir (dir->wd, dir);
ip_unmap_path_dir (dir->path, dir);
ip_watched_dir_free (dir);
}
return TRUE;
}
static ip_watched_dir_t *
ip_watched_dir_new (const char *path,
gint32 wd)
{
ip_watched_dir_t *dir = g_new0 (ip_watched_dir_t, 1);
dir->path = g_strdup (path);
dir->files_hash = g_hash_table_new (g_str_hash, g_str_equal);
dir->wd = wd;
return dir;
}
static void
ip_watched_dir_free (ip_watched_dir_t *dir)
{
g_assert_cmpint (g_hash_table_size (dir->files_hash), ==, 0);
g_assert (dir->subs == NULL);
g_free (dir->path);
g_free (dir);
}
static void
ip_wd_delete (gpointer data,
gpointer user_data)
{
ip_watched_dir_t *dir = data;
GList *l = NULL;
for (l = dir->subs; l; l = l->next)
{
inotify_sub *sub = l->data;
/* Add subscription to missing list */
_im_add (sub);
}
ip_unmap_all_subs (dir);
/* Unassociate the path and the directory */
ip_unmap_path_dir (dir->path, dir);
ip_watched_dir_free (dir);
}
static void
ip_event_dispatch (GList *dir_list,
GList *pair_dir_list,
GList *file_list,
GList *pair_file_list,
ik_event_t *event)
{
GList *l;
if (!event)
return;
for (l = dir_list; l; l = l->next)
{
GList *subl;
ip_watched_dir_t *dir = l->data;
for (subl = dir->subs; subl; subl = subl->next)
{
inotify_sub *sub = subl->data;
/* If the subscription and the event
* contain a filename and they don't
* match, we don't deliver this event.
*/
if (sub->filename &&
event->name &&
strcmp (sub->filename, event->name))
continue;
/* If the subscription has a filename
* but this event doesn't, we don't
* deliver this event.
*/
if (sub->filename && !event->name)
continue;
/* If we're also watching the file directly
* don't report events that will also be
* reported on the file itself.
*/
if (sub->hardlinks)
{
event->mask &= ~IP_INOTIFY_FILE_MASK;
if (!event->mask)
continue;
}
/* FIXME: We might need to synthesize
* DELETE/UNMOUNT events when
* the filename doesn't match
*/
event_callback (event, sub, FALSE);
if (sub->hardlinks)
{
ip_watched_file_t *file;
file = g_hash_table_lookup (dir->files_hash, sub->filename);
if (file != NULL)
{
if (event->mask & (IN_MOVED_FROM | IN_DELETE))
ip_watched_file_stop (file);
if (event->mask & (IN_MOVED_TO | IN_CREATE))
ip_watched_file_start (file);
}
}
}
}
for (l = file_list; l; l = l->next)
{
ip_watched_file_t *file = l->data;
GList *subl;
for (subl = file->subs; subl; subl = subl->next)
{
inotify_sub *sub = subl->data;
event_callback (event, sub, TRUE);
}
}
if (!event->pair)
return;
for (l = pair_dir_list; l; l = l->next)
{
GList *subl;
ip_watched_dir_t *dir = l->data;
for (subl = dir->subs; subl; subl = subl->next)
{
inotify_sub *sub = subl->data;
/* If the subscription and the event
* contain a filename and they don't
* match, we don't deliver this event.
*/
if (sub->filename &&
event->pair->name &&
strcmp (sub->filename, event->pair->name))
continue;
/* If the subscription has a filename
* but this event doesn't, we don't
* deliver this event.
*/
if (sub->filename && !event->pair->name)
continue;
/* If we're also watching the file directly
* don't report events that will also be
* reported on the file itself.
*/
if (sub->hardlinks)
{
event->mask &= ~IP_INOTIFY_FILE_MASK;
if (!event->mask)
continue;
}
/* FIXME: We might need to synthesize
* DELETE/UNMOUNT events when
* the filename doesn't match
*/
event_callback (event->pair, sub, FALSE);
if (sub->hardlinks)
{
ip_watched_file_t *file;
file = g_hash_table_lookup (dir->files_hash, sub->filename);
if (file != NULL)
{
if (event->pair->mask & (IN_MOVED_FROM | IN_DELETE))
ip_watched_file_stop (file);
if (event->pair->mask & (IN_MOVED_TO | IN_CREATE))
ip_watched_file_start (file);
}
}
}
}
for (l = pair_file_list; l; l = l->next)
{
ip_watched_file_t *file = l->data;
GList *subl;
for (subl = file->subs; subl; subl = subl->next)
{
inotify_sub *sub = subl->data;
event_callback (event->pair, sub, TRUE);
}
}
}
static void
ip_event_callback (ik_event_t *event)
{
GList* dir_list = NULL;
GList* pair_dir_list = NULL;
GList *file_list = NULL;
GList *pair_file_list = NULL;
/* We can ignore the IGNORED events */
if (event->mask & IN_IGNORED)
{
_ik_event_free (event);
return;
}
dir_list = g_hash_table_lookup (wd_dir_hash, GINT_TO_POINTER (event->wd));
file_list = g_hash_table_lookup (wd_file_hash, GINT_TO_POINTER (event->wd));
if (event->pair)
{
pair_dir_list = g_hash_table_lookup (wd_dir_hash, GINT_TO_POINTER (event->pair->wd));
pair_file_list = g_hash_table_lookup (wd_file_hash, GINT_TO_POINTER (event->pair->wd));
}
if (event->mask & IP_INOTIFY_DIR_MASK)
ip_event_dispatch (dir_list, pair_dir_list, file_list, pair_file_list, event);
/* We have to manage the missing list
* when we get an event that means the
* file has been deleted/moved/unmounted.
*/
if (event->mask & IN_DELETE_SELF ||
event->mask & IN_MOVE_SELF ||
event->mask & IN_UNMOUNT)
{
/* Add all subscriptions to missing list */
g_list_foreach (dir_list, ip_wd_delete, NULL);
/* Unmap all directories attached to this wd */
ip_unmap_wd (event->wd);
}
_ik_event_free (event);
}
const char *
_ip_get_path_for_wd (gint32 wd)
{
GList *dir_list;
ip_watched_dir_t *dir;
g_assert (wd >= 0);
dir_list = g_hash_table_lookup (wd_dir_hash, GINT_TO_POINTER (wd));
if (dir_list)
{
dir = dir_list->data;
if (dir)
return dir->path;
}
return NULL;
}