+/*
+ * hardlink.c
+ *
+ * Code to deal with hard links in WIMs. Essentially, the WIM dentries are put
+ * into a hash table indexed by the hard link group ID field, then for each hard
+ * link group, a linked list is made to connect the dentries.
+ */
+
+/*
+ * Copyright (C) 2012 Eric Biggers
+ *
+ * This file is part of wimlib, a library for working with WIM files.
+ *
+ * wimlib 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 2.1 of the License, or (at your option)
+ * any later version.
+ *
+ * wimlib 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 wimlib; if not, see http://www.gnu.org/licenses/.
+ */
+
#include "wimlib_internal.h"
#include "dentry.h"
#include "list.h"
#include "lookup_table.h"
+/* Hard link group; it's identified by its hard link group ID and consists of a
+ * circularly linked list of dentries. */
struct link_group {
u64 link_group_id;
struct link_group *next;
- struct list_head dentry_list;
+ struct list_head *dentry_list;
};
+/* Hash table to find hard link groups, identified by their hard link group ID.
+ * */
struct link_group_table {
struct link_group **array;
u64 num_entries;
u64 capacity;
+ struct link_group *singles;
};
-#include <sys/mman.h>
-
+/* Returns pointer to a new link group table having the specified capacity */
struct link_group_table *new_link_group_table(u64 capacity)
{
- return (struct link_group_table*)new_lookup_table(capacity);
+ struct link_group_table *table;
+ struct link_group **array;
+
+ table = MALLOC(sizeof(struct link_group_table));
+ if (!table)
+ goto err;
+ array = CALLOC(capacity, sizeof(array[0]));
+ if (!array) {
+ FREE(table);
+ goto err;
+ }
+ table->num_entries = 0;
+ table->capacity = capacity;
+ table->array = array;
+ table->singles = NULL;
+ return table;
+err:
+ ERROR("Failed to allocate memory for link group table with capacity %zu",
+ capacity);
+ return NULL;
}
-/* Insert a dentry into the hard link group table based on its hard link group
+/*
+ * Insert a dentry into the hard link group table based on its hard link group
* ID.
*
* If there is already a dentry in the table having the same hard link group ID,
* we link the dentries together in a circular list.
*
- * If the hard link group ID is 0, this is a no-op and the dentry is not
- * inserted.
+ * If the hard link group ID is 0, this indicates a dentry that's in a hard link
+ * group by itself (has a link count of 1). We can't insert it into the hash
+ * table itself because we don't know what hard link group IDs are available to
+ * give it (this could be kept track of but would be more difficult). Instead
+ * we keep a linked list of the single dentries, and assign them hard link group
+ * IDs later.
*/
-int link_group_table_insert(struct dentry *dentry, struct link_group_table *table)
+int link_group_table_insert(struct dentry *dentry, void *__table)
{
+ struct link_group_table *table = __table;
size_t pos;
struct link_group *group;
- if (dentry->hard_link == 0)
- return 0;
+ if (dentry->hard_link == 0) {
+ /* Single group--- Add to the singles list (we can't put it in
+ * the table itself because all the singles have a link group ID
+ * of 0) */
+ group = MALLOC(sizeof(struct link_group));
+ if (!group)
+ return WIMLIB_ERR_NOMEM;
+ group->link_group_id = 0;
+ group->next = table->singles;
+ table->singles = group;
+ INIT_LIST_HEAD(&dentry->link_group_list);
+ group->dentry_list = &dentry->link_group_list;
+ } else {
+ /* Hard link group that may should multiple dentries (the code
+ * will work even if the group actually contains only 1 dentry
+ * though) */
- /* Try adding to existing hard link group */
- pos = dentry->hard_link % table->capacity;
- group = table->array[pos];
- while (group) {
- if (group->link_group_id == dentry->hard_link) {
- list_add(&dentry->link_group_list, &group->dentry_list);
- return 0;
+ /* Try adding to existing hard link group */
+ pos = dentry->hard_link % table->capacity;
+ group = table->array[pos];
+ while (group) {
+ if (group->link_group_id == dentry->hard_link) {
+ list_add(&dentry->link_group_list,
+ group->dentry_list);
+ return 0;
+ }
+ group = group->next;
}
- group = group->next;
- }
- /* Add new hard link group to the table */
+ /* Add new hard link group to the table */
- group = MALLOC(sizeof(struct link_group));
- if (!group)
- return WIMLIB_ERR_NOMEM;
- group->link_group_id = dentry->hard_link;
- group->next = table->array[pos];
- INIT_LIST_HEAD(&group->dentry_list);
- list_add(&dentry->link_group_list, &group->dentry_list);
- table->array[pos] = group;
+ group = MALLOC(sizeof(struct link_group));
+ if (!group)
+ return WIMLIB_ERR_NOMEM;
+ group->link_group_id = dentry->hard_link;
+ group->next = table->array[pos];
+ INIT_LIST_HEAD(&dentry->link_group_list);
+ group->dentry_list = &dentry->link_group_list;
+ table->array[pos] = group;
- /* XXX Make the table grow when too many entries have been inserted. */
- table->num_entries++;
+ /* XXX Make the table grow when too many entries have been
+ * inserted. */
+ table->num_entries++;
+ }
return 0;
}
/* Frees a link group table. */
void free_link_group_table(struct link_group_table *table)
{
+ struct link_group *single, *next;
+
if (!table)
return;
if (table->array) {
}
FREE(table->array);
}
+ single = table->singles;
+ while (single) {
+ next = single->next;
+ FREE(single);
+ single = next;
+ }
+
FREE(table);
}
* next available link group ID. */
u64 assign_link_groups(struct link_group_table *table)
{
- struct link_group *remaining_groups = NULL;
+ DEBUG("Assigning link groups");
+
+ /* Assign consecutive link group IDs to each link group in the hash
+ * table */
u64 id = 1;
for (u64 i = 0; i < table->capacity; i++) {
struct link_group *group = table->array[i];
struct link_group *next_group;
struct dentry *dentry;
+ struct list_head *cur;
while (group) {
- next_group = group->next;
- if (list_is_singular(&group->dentry_list)) {
- /* Hard link group of size 1. Change the hard
- * link ID to 0 and discard the link_group */
- dentry = container_of(group->dentry_list.next,
+ cur = group->dentry_list;
+ do {
+ dentry = container_of(cur,
struct dentry,
link_group_list);
- dentry->hard_link = 0;
- FREE(group);
- } else {
- /* Hard link group of size > 1. Assign the
- * dentries in the group the next available hard
- * link IDs and queue the group to be
- * re-inserted into the table. */
- list_for_each_entry(dentry, &group->dentry_list,
- link_group_list)
- dentry->hard_link = id;
- group->next = remaining_groups;
- remaining_groups = group;
- id++;
- }
- group = next_group;
+ dentry->hard_link = id;
+ cur = cur->next;
+ } while (cur != group->dentry_list);
+ id++;
+ group = group->next;
}
}
- memset(table->array, 0, table->capacity * sizeof(table->array[0]));
- table->num_entries = 0;
- while (remaining_groups) {
- struct link_group *group = remaining_groups;
- size_t pos = group->link_group_id % table->capacity;
+ /* Assign link group IDs to the link groups that previously had link
+ * group IDs of 0, and insert them into the hash table */
+ struct link_group *single = table->singles;
+ while (single) {
+ struct dentry *dentry;
+ struct link_group *next_single;
+ size_t pos;
- table->num_entries++;
- group->next = table->array[pos];
- table->array[pos] = group;
- remaining_groups = remaining_groups->next;
+ next_single = single->next;
+
+ dentry = container_of(single->dentry_list, struct dentry,
+ link_group_list);
+ dentry->hard_link = id;
+
+ pos = id % table->capacity;
+ single->next = table->array[pos];
+ table->array[pos] = single;
+
+ single = next_single;
+ id++;
}
+ table->singles = NULL;
return id;
}
-#if 0
-/* Load a dentry tree into the link group table */
-int load_link_groups(struct link_group_table *table, struct dentry *root)
+static bool dentries_have_same_ads(const struct dentry *d1,
+ const struct dentry *d2)
+{
+ /* Verify stream names and hashes are the same */
+ for (u16 i = 0; i < d1->num_ads; i++) {
+ if (strcmp(d1->ads_entries[i].stream_name_utf8,
+ d2->ads_entries[i].stream_name_utf8) != 0)
+ return false;
+ if (!hashes_equal(d1->ads_entries[i].hash,
+ d2->ads_entries[i].hash))
+ return false;
+ }
+ return true;
+}
+
+/* Share the alternate stream entries between hard-linked dentries. */
+static int share_dentry_ads(struct dentry *owner, struct dentry *user)
+{
+ const char *mismatch_type;
+ wimlib_assert(owner->num_ads == 0 ||
+ owner->ads_entries != user->ads_entries);
+ if (owner->attributes != user->attributes) {
+ mismatch_type = "attributes";
+ goto mismatch;
+ }
+ if (owner->attributes & FILE_ATTRIBUTE_DIRECTORY) {
+ WARNING("`%s' is hard-linked to `%s', which is a directory ",
+ user->full_path_utf8, owner->full_path_utf8);
+ return WIMLIB_ERR_INVALID_DENTRY;
+ }
+ if (owner->security_id != user->security_id) {
+ mismatch_type = "security ID";
+ goto mismatch;
+ }
+ if (!hashes_equal(owner->hash, user->hash)) {
+ mismatch_type = "main file resource";
+ goto mismatch;
+ }
+ if (!dentries_have_same_ads(owner, user)) {
+ mismatch_type = "Alternate Stream Entries";
+ goto mismatch;
+ }
+ dentry_free_ads_entries(user);
+ user->ads_entries = owner->ads_entries;
+ user->ads_entries_status = ADS_ENTRIES_USER;
+ return 0;
+mismatch:
+ WARNING("Dentries `%s' and `%s' in the same hard-link group but "
+ "do not share the same %s",
+ owner->full_path_utf8, user->full_path_utf8,
+ mismatch_type);
+ return WIMLIB_ERR_INVALID_DENTRY;
+}
+
+static int link_group_free_duplicate_data(struct link_group *group,
+ struct link_group **bad_links)
{
- int ret = for_dentry_in_tree(dentry, link_group_table_insert, table);
- if (ret == 0)
- assign_link_groups(table);
- return ret;
+ struct dentry *owner, *user, *tmp;
+
+ owner = container_of(group->dentry_list, struct dentry,
+ link_group_list);
+ owner->ads_entries_status = ADS_ENTRIES_OWNER;
+
+ list_for_each_entry_safe(user, tmp, group->dentry_list,
+ link_group_list)
+ {
+ /* I would like it to be an error if two dentries are in the
+ * same hard link group but have irreconcilable differences such
+ * as different file permissions, but unfortunately some of M$'s
+ * WIMs contain many instances of this error. This problem is
+ * worked around here by splitting each offending dentry off
+ * into its own hard link group. */
+ if (share_dentry_ads(owner, user) != 0) {
+ struct link_group *single;
+ single = MALLOC(sizeof(struct link_group));
+ if (!single)
+ return WIMLIB_ERR_NOMEM;
+ list_del(&user->link_group_list);
+ INIT_LIST_HEAD(&user->link_group_list);
+ single->link_group_id = 0;
+ single->next = *bad_links;
+ single->dentry_list = &user->link_group_list;
+ *bad_links = single;
+ user->ads_entries_status = ADS_ENTRIES_OWNER;
+ }
+ }
+ return 0;
+}
+
+/*
+ * Goes through each link group and shares the ads_entries (Alternate Data
+ * Stream entries) field of each dentry between members of a hard link group.
+ *
+ * In the process, the dentries in each link group are checked for consistency.
+ * If they contain data features that indicate they cannot really be in the same
+ * hard link group, this should be an error, but in reality this case needs to
+ * be handled, so we split the dentries into different hard link groups.
+ *
+ * One of the dentries in the group is arbitrarily assigned the role of "owner"
+ * (ADS_ENTRIES_OWNER), while the others are "users" (ADS_ENTRIES_USER).
+ */
+int link_groups_free_duplicate_data(struct link_group_table *table)
+{
+ for (u64 i = 0; i < table->capacity; i++) {
+ struct link_group *group = table->array[i];
+ while (group) {
+ int ret;
+ ret = link_group_free_duplicate_data(group,
+ &table->singles);
+ if (ret != 0)
+ return ret;
+ group = group->next;
+ }
+ }
+ return 0;
}
-#endif
git://wimlib.net / wimlib / blobdiff