glib/gio/gkeyfilesettingsbackend.c
2010-09-24 18:24:41 -03:00

666 lines
19 KiB
C

/*
* Copyright © 2010 Codethink Limited
* Copyright © 2010 Novell, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the licence, or (at your option) any later version.
*
* This 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Authors: Vincent Untz <vuntz@gnome.org>
* Ryan Lortie <desrt@desrt.ca>
*/
#include "config.h"
#include <stdio.h>
#include <string.h>
#include "gfile.h"
#include "gfileinfo.h"
#include "gfilemonitor.h"
#include "gsimplepermission.h"
#include "gsettingsbackend.h"
#define G_TYPE_KEYFILE_SETTINGS_BACKEND (g_keyfile_settings_backend_get_type ())
#define G_KEYFILE_SETTINGS_BACKEND(inst) (G_TYPE_CHECK_INSTANCE_CAST ((inst), \
G_TYPE_KEYFILE_SETTINGS_BACKEND, \
GKeyfileSettingsBackend))
#define G_IS_KEYFILE_SETTINGS_BACKEND(inst) (G_TYPE_CHECK_INSTANCE_TYPE ((inst), \
G_TYPE_KEYFILE_SETTINGS_BACKEND))
typedef GSettingsBackendClass GKeyfileSettingsBackendClass;
typedef struct
{
GSettingsBackend parent_instance;
GKeyFile *keyfile;
GPermission *permission;
gboolean writable;
gchar *prefix;
gint prefix_len;
gchar *root_group;
gint root_group_len;
GFile *file;
GFileMonitor *file_monitor;
guint8 digest[32];
GFile *dir;
GFileMonitor *dir_monitor;
} GKeyfileSettingsBackend;
static GType g_keyfile_settings_backend_get_type (void);
G_DEFINE_TYPE (GKeyfileSettingsBackend,
g_keyfile_settings_backend,
G_TYPE_SETTINGS_BACKEND)
static void
compute_checksum (guint8 *digest,
gconstpointer contents,
gsize length)
{
GChecksum *checksum;
gsize len = 32;
checksum = g_checksum_new (G_CHECKSUM_SHA256);
g_checksum_update (checksum, contents, length);
g_checksum_get_digest (checksum, digest, &len);
g_checksum_free (checksum);
g_assert (len == 32);
}
static void
g_keyfile_settings_backend_keyfile_write (GKeyfileSettingsBackend *kfsb)
{
gchar *contents;
gsize length;
contents = g_key_file_to_data (kfsb->keyfile, &length, NULL);
g_file_replace_contents (kfsb->file, contents, length, NULL, FALSE,
G_FILE_CREATE_REPLACE_DESTINATION,
NULL, NULL, NULL);
compute_checksum (kfsb->digest, contents, length);
g_free (contents);
}
static gboolean
group_name_matches (const gchar *group_name,
const gchar *prefix)
{
/* sort of like g_str_has_prefix() except that it must be an exact
* match or the prefix followed by '/'.
*
* for example 'a' is a prefix of 'a' and 'a/b' but not 'ab'.
*/
gint i;
for (i = 0; prefix[i]; i++)
if (prefix[i] != group_name[i])
return FALSE;
return group_name[i] == '\0' || group_name[i] == '/';
}
static gboolean
convert_path (GKeyfileSettingsBackend *kfsb,
const gchar *key,
gchar **group,
gchar **basename)
{
gint key_len = strlen (key);
gint i;
if (key_len < kfsb->prefix_len ||
memcmp (key, kfsb->prefix, kfsb->prefix_len) != 0)
return FALSE;
key_len -= kfsb->prefix_len;
key += kfsb->prefix_len;
for (i = key_len; i >= 0; i--)
if (key[i] == '/')
break;
if (kfsb->root_group)
{
/* if a root_group was specified, make sure the user hasn't given
* a path that ghosts that group name
*/
if (i == kfsb->root_group_len && memcmp (key, kfsb->root_group, i) == 0)
return FALSE;
}
else
{
/* if no root_group was given, ensure that the user gave a path */
if (i == -1)
return FALSE;
}
if (group)
{
if (i >= 0)
{
*group = g_memdup (key, i + 1);
(*group)[i] = '\0';
}
else
*group = g_strdup (kfsb->root_group);
}
if (basename)
*basename = g_memdup (key + i + 1, key_len - i);
return TRUE;
}
gboolean
path_is_valid (GKeyfileSettingsBackend *kfsb,
const gchar *path)
{
return convert_path (kfsb, path, NULL, NULL);
}
static GVariant *
get_from_keyfile (GKeyfileSettingsBackend *kfsb,
const GVariantType *type,
const gchar *key)
{
GVariant *return_value = NULL;
gchar *group, *name;
if (convert_path (kfsb, key, &group, &name))
{
gchar *str;
g_assert (*name);
str = g_key_file_get_value (kfsb->keyfile, group, name, NULL);
if (str)
{
return_value = g_variant_parse (type, str, NULL, NULL, NULL);
g_free (str);
}
g_free (group);
g_free (name);
}
return return_value;
}
static gboolean
set_to_keyfile (GKeyfileSettingsBackend *kfsb,
const gchar *key,
GVariant *value)
{
gchar *group, *name;
if (convert_path (kfsb, key, &group, &name))
{
if (value)
{
gchar *str = g_variant_print (value, FALSE);
g_key_file_set_value (kfsb->keyfile, group, name, str);
g_variant_unref (g_variant_ref_sink (value));
g_free (str);
}
else
{
if (*name == '\0')
{
gchar **groups;
gint i;
groups = g_key_file_get_groups (kfsb->keyfile, NULL);
for (i = 0; groups[i]; i++)
if (group_name_matches (groups[i], group))
g_key_file_remove_group (kfsb->keyfile, groups[i], NULL);
g_strfreev (groups);
}
else
g_key_file_remove_key (kfsb->keyfile, group, name, NULL);
}
g_free (group);
g_free (name);
return TRUE;
}
return FALSE;
}
static GVariant *
g_keyfile_settings_backend_read (GSettingsBackend *backend,
const gchar *key,
const GVariantType *expected_type,
gboolean default_value)
{
GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (backend);
if (default_value)
return NULL;
return get_from_keyfile (kfsb, expected_type, key);
}
typedef struct
{
GKeyfileSettingsBackend *kfsb;
gboolean failed;
} WriteManyData;
static gboolean
g_keyfile_settings_backend_write_one (gpointer key,
gpointer value,
gpointer user_data)
{
WriteManyData *data = user_data;
gboolean success;
success = set_to_keyfile (data->kfsb, key, value);
g_assert (success);
return FALSE;
}
static gboolean
g_keyfile_settings_backend_check_one (gpointer key,
gpointer value,
gpointer user_data)
{
WriteManyData *data = user_data;
return data->failed = !path_is_valid (data->kfsb, key);
}
static gboolean
g_keyfile_settings_backend_write_tree (GSettingsBackend *backend,
GTree *tree,
gpointer origin_tag)
{
WriteManyData data = { G_KEYFILE_SETTINGS_BACKEND (backend) };
if (!data.kfsb->writable)
return FALSE;
g_tree_foreach (tree, g_keyfile_settings_backend_check_one, &data);
if (data.failed)
return FALSE;
g_tree_foreach (tree, g_keyfile_settings_backend_write_one, &data);
g_keyfile_settings_backend_keyfile_write (data.kfsb);
g_settings_backend_changed_tree (backend, tree, origin_tag);
return TRUE;
}
static gboolean
g_keyfile_settings_backend_write (GSettingsBackend *backend,
const gchar *key,
GVariant *value,
gpointer origin_tag)
{
GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (backend);
gboolean success;
if (!kfsb->writable)
return FALSE;
success = set_to_keyfile (kfsb, key, value);
if (success)
{
g_settings_backend_changed (backend, key, origin_tag);
g_keyfile_settings_backend_keyfile_write (kfsb);
}
return success;
}
static void
g_keyfile_settings_backend_reset (GSettingsBackend *backend,
const gchar *key,
gpointer origin_tag)
{
GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (backend);
if (set_to_keyfile (kfsb, key, NULL))
g_keyfile_settings_backend_keyfile_write (kfsb);
g_settings_backend_changed (backend, key, origin_tag);
}
static gboolean
g_keyfile_settings_backend_get_writable (GSettingsBackend *backend,
const gchar *name)
{
GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (backend);
return kfsb->writable && path_is_valid (kfsb, name);
}
static GPermission *
g_keyfile_settings_backend_get_permission (GSettingsBackend *backend,
const gchar *path)
{
GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (backend);
return g_object_ref (kfsb->permission);
}
static void
keyfile_to_tree (GKeyfileSettingsBackend *kfsb,
GTree *tree,
GKeyFile *keyfile,
gboolean dup_check)
{
gchar **groups;
gint i;
groups = g_key_file_get_groups (keyfile, NULL);
for (i = 0; groups[i]; i++)
{
gboolean is_root_group;
gchar **keys;
gint j;
is_root_group = g_strcmp0 (kfsb->root_group, groups[i]) == 0;
/* reject group names that will form invalid key names */
if (!is_root_group &&
(g_str_has_prefix (groups[i], "/") ||
g_str_has_suffix (groups[i], "/") || strstr (groups[i], "//")))
continue;
keys = g_key_file_get_keys (keyfile, groups[i], NULL, NULL);
for (j = 0; keys[j]; j++)
{
gchar *path, *value;
/* reject key names with slashes in them */
if (strchr (keys[j], '/'))
continue;
if (is_root_group)
path = g_strdup_printf ("%s%s", kfsb->prefix, keys[j]);
else
path = g_strdup_printf ("%s%s/%s", kfsb->prefix, groups[i], keys[j]);
value = g_key_file_get_value (keyfile, groups[i], keys[j], NULL);
if (dup_check && g_strcmp0 (g_tree_lookup (tree, path), value) == 0)
{
g_tree_remove (tree, path);
g_free (value);
g_free (path);
}
else
g_tree_insert (tree, path, value);
}
g_strfreev (keys);
}
g_strfreev (groups);
}
static void
g_keyfile_settings_backend_keyfile_reload (GKeyfileSettingsBackend *kfsb)
{
guint8 digest[32];
gchar *contents;
gsize length;
contents = NULL;
length = 0;
g_file_load_contents (kfsb->file, NULL, &contents, &length, NULL, NULL);
compute_checksum (digest, contents, length);
if (memcmp (kfsb->digest, digest, sizeof digest) != 0)
{
GKeyFile *keyfiles[2];
GTree *tree;
tree = g_tree_new_full ((GCompareDataFunc) strcmp, NULL,
g_free, g_free);
keyfiles[0] = kfsb->keyfile;
keyfiles[1] = g_key_file_new ();
if (length > 0)
g_key_file_load_from_data (keyfiles[1], contents, length,
G_KEY_FILE_KEEP_COMMENTS |
G_KEY_FILE_KEEP_TRANSLATIONS, NULL);
keyfile_to_tree (kfsb, tree, keyfiles[0], FALSE);
keyfile_to_tree (kfsb, tree, keyfiles[1], TRUE);
g_key_file_free (keyfiles[0]);
kfsb->keyfile = keyfiles[1];
if (g_tree_nnodes (tree) > 0)
g_settings_backend_changed_tree (&kfsb->parent_instance, tree, NULL);
g_tree_unref (tree);
memcpy (kfsb->digest, digest, sizeof digest);
}
g_free (contents);
}
static void
g_keyfile_settings_backend_keyfile_writable (GKeyfileSettingsBackend *kfsb)
{
GFileInfo *fileinfo;
gboolean writable;
fileinfo = g_file_query_info (kfsb->dir, "access::*", 0, NULL, NULL);
if (fileinfo)
{
writable =
g_file_info_get_attribute_boolean (fileinfo, G_FILE_ATTRIBUTE_ACCESS_CAN_WRITE) &&
g_file_info_get_attribute_boolean (fileinfo, G_FILE_ATTRIBUTE_ACCESS_CAN_EXECUTE);
g_object_unref (fileinfo);
}
else
writable = FALSE;
if (writable != kfsb->writable)
{
kfsb->writable = writable;
g_settings_backend_path_writable_changed (&kfsb->parent_instance, "/");
}
}
static void
g_keyfile_settings_backend_finalize (GObject *object)
{
GKeyfileSettingsBackend *kfsb = G_KEYFILE_SETTINGS_BACKEND (object);
g_key_file_free (kfsb->keyfile);
g_object_unref (kfsb->permission);
g_file_monitor_cancel (kfsb->file_monitor);
g_object_unref (kfsb->file_monitor);
g_object_unref (kfsb->file);
g_file_monitor_cancel (kfsb->dir_monitor);
g_object_unref (kfsb->dir_monitor);
g_object_unref (kfsb->dir);
g_free (kfsb->root_group);
g_free (kfsb->prefix);
G_OBJECT_CLASS (g_keyfile_settings_backend_parent_class)
->finalize (object);
}
static void
g_keyfile_settings_backend_init (GKeyfileSettingsBackend *kfsb)
{
}
static void
g_keyfile_settings_backend_class_init (GKeyfileSettingsBackendClass *class)
{
GObjectClass *object_class = G_OBJECT_CLASS (class);
object_class->finalize = g_keyfile_settings_backend_finalize;
class->read = g_keyfile_settings_backend_read;
class->write = g_keyfile_settings_backend_write;
class->write_tree = g_keyfile_settings_backend_write_tree;
class->reset = g_keyfile_settings_backend_reset;
class->get_writable = g_keyfile_settings_backend_get_writable;
class->get_permission = g_keyfile_settings_backend_get_permission;
/* No need to implement subscribed/unsubscribe: the only point would be to
* stop monitoring the file when there's no GSettings anymore, which is no
* big win. */
}
static void
file_changed (GFileMonitor *monitor,
GFile *file,
GFile *other_file,
GFileMonitorEvent event_type,
gpointer user_data)
{
GKeyfileSettingsBackend *kfsb = user_data;
g_keyfile_settings_backend_keyfile_reload (kfsb);
}
static void
dir_changed (GFileMonitor *monitor,
GFile *file,
GFile *other_file,
GFileMonitorEvent event_type,
gpointer user_data)
{
GKeyfileSettingsBackend *kfsb = user_data;
g_keyfile_settings_backend_keyfile_writable (kfsb);
}
/**
* g_keyfile_settings_backend_new:
* @filename: the filename of the keyfile
* @root_path: the path under which all settings keys appear
* @root_group: (allow-none): the group name corresponding to
* @root_path, or %NULL
* @returns: (transfer full): a keyfile-backed #GSettingsBackend
*
* Creates a keyfile-backed #GSettingsBackend.
*
* The filename of the keyfile to use is given by @filename.
*
* All settings read to or written from the backend must fall under the
* path given in @root_path (which must start and end with a slash and
* not contain two consecutive slashes). @root_path may be "/".
*
* If @root_group is non-%NULL then it specifies the name of the keyfile
* group used for keys that are written directly below @root_path. For
* example, if @root_path is "/apps/example/" and @root_group is
* "toplevel", then settings the key "/apps/example/enabled" to a value
* of %TRUE will cause the following to appear in the keyfile:
*
* |[
* [toplevel]
* enabled=true
* ]|
*
* If @root_group is %NULL then it is not permitted to store keys
* directly below the @root_path.
*
* For keys not stored directly below @root_path (ie: in a sub-path),
* the name of the subpath (with the final slash stripped) is used as
* the name of the keyfile group. To continue the example, if
* "/apps/example/profiles/default/font-size" were set to
* 12 then the following would appear in the keyfile:
*
* |[
* [profiles/default]
* font-size=12
* ]|
*
* The backend will refuse writes (and return writability as being
* %FALSE) for keys outside of @root_path and, in the event that
* @root_group is %NULL, also for keys directly under @root_path.
* Writes will also be refused if the backend detects that it has the
* inability to rewrite the keyfile (ie: the containing directory is not
* writable).
*
* There is no checking done for your key namespace clashing with the
* syntax of the key file format. For example, if you have '[' or ']'
* characters in your path names or '=' in your key names you may be in
* trouble.
**/
GSettingsBackend *
g_keyfile_settings_backend_new (const gchar *filename,
const gchar *root_path,
const gchar *root_group)
{
GKeyfileSettingsBackend *kfsb;
g_return_val_if_fail (filename != NULL, NULL);
g_return_val_if_fail (root_path != NULL, NULL);
g_return_val_if_fail (g_str_has_prefix (root_path, "/"), NULL);
g_return_val_if_fail (g_str_has_suffix (root_path, "/"), NULL);
g_return_val_if_fail (strstr (root_path, "//") == NULL, NULL);
kfsb = g_object_new (G_TYPE_KEYFILE_SETTINGS_BACKEND, NULL);
kfsb->keyfile = g_key_file_new ();
kfsb->permission = g_simple_permission_new (TRUE);
kfsb->file = g_file_new_for_path (filename);
kfsb->dir = g_file_get_parent (kfsb->file);
g_file_make_directory_with_parents (kfsb->dir, NULL, NULL);
kfsb->file_monitor = g_file_monitor_file (kfsb->file, 0, NULL, NULL);
kfsb->dir_monitor = g_file_monitor_file (kfsb->dir, 0, NULL, NULL);
kfsb->prefix_len = strlen (root_path);
kfsb->prefix = g_strdup (root_path);
if (root_group)
{
kfsb->root_group_len = strlen (root_group);
kfsb->root_group = g_strdup (root_group);
}
compute_checksum (kfsb->digest, NULL, 0);
g_signal_connect (kfsb->file_monitor, "changed",
G_CALLBACK (file_changed), kfsb);
g_signal_connect (kfsb->dir_monitor, "changed",
G_CALLBACK (dir_changed), kfsb);
g_keyfile_settings_backend_keyfile_writable (kfsb);
g_keyfile_settings_backend_keyfile_reload (kfsb);
return G_SETTINGS_BACKEND (kfsb);
}