X-Git-Url: https://wimlib.net/git/?a=blobdiff_plain;f=src%2Fhardlink.c;h=6200277713b670216123d16eaedb5222b3705307;hb=68b023ab834029db11ce9bf150dadd9c80e59404;hp=a5d8b9fae05fae57f56dae0fab55262bcb9456ef;hpb=72cc9a31b518ca830fcc7a2ed74a20415d6e13ec;p=wimlib

diff --git a/src/hardlink.c b/src/hardlink.c
index a5d8b9fa..62002777 100644
--- a/src/hardlink.c
+++ b/src/hardlink.c
@@ -1,149 +1,583 @@
+/*
+ * 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 {
+	/* Fields for the hash table */
 	struct link_group **array;
 	u64 num_entries;
 	u64 capacity;
-};
 
-#include <sys/mman.h>
+	/* 
+	 * Linked list of "extra" groups.  These may be:
+	 *
+	 * - Hard link groups of size 1, which are all allowed to have 0 for
+	 *   their hard link group ID, meaning we cannot insert them into the
+	 *   hash table
+	 * - Groups we create ourselves by splitting a nominal hard link group
+	 *   due to inconsistencies in the dentries.  These groups will have a
+	 *   hard link group ID duplicated with some other group until
+	 *   assign_link_group_ids() is called.
+	 */
+	struct link_group *extra_groups;
+};
 
-struct link_group_table *new_link_group_table(u64 capacity)
+/* Returns pointer to a new link group table having the specified capacity */
+struct link_group_table *new_link_group_table(size_t 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->extra_groups = 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) {
+		/* Single group--- Add to the list of extra groups (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->extra_groups;
+		table->extra_groups  = group;
 		INIT_LIST_HEAD(&dentry->link_group_list);
-		return 0;
-	}
+		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;
 }
 
+static void free_link_group_list(struct link_group *group)
+{
+	struct link_group *next_group;
+	while (group) {
+		next_group = group->next;
+		FREE(group);
+		group = next_group;
+	}
+}
+
 /* 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) {
-		for (u64 i = 0; i < table->capacity; i++) {
-			struct link_group *group = table->array[i];
-			struct link_group *next;
-			while (group) {
-				next = group->next;
-				FREE(group);
-				group = next;
-			}
-		}
-		FREE(table->array);
-	}
+	if (table->array)
+		for (size_t i = 0; i < table->capacity; i++)
+			free_link_group_list(table->array[i]);
+	free_link_group_list(table->extra_groups);
+
 	FREE(table);
 }
 
+u64 assign_link_group_ids_to_list(struct link_group *group, u64 id)
+{
+	struct dentry *dentry;
+	struct list_head *cur;
+	while (group) {
+		cur = group->dentry_list;
+		do {
+			dentry = container_of(cur,
+					      struct dentry,
+					      link_group_list);
+			dentry->hard_link = id;
+			cur = cur->next;
+		} while (cur != group->dentry_list);
+		group->link_group_id = id;
+		id++;
+		group = group->next;
+	}
+	return id;
+}
+
+/* Insert the link groups in the `extra_groups' list into the hash table */
+static void insert_extra_groups(struct link_group_table *table)
+{
+	struct link_group *group, *next_group;
+	size_t pos;
+
+	group = table->extra_groups;
+	while (group) {
+		next_group = group->next;
+		pos = group->link_group_id % table->capacity;
+		group->next = table->array[pos];
+		table->array[pos] = group;
+		group = next_group;
+	}
+	table->extra_groups = NULL;
+}
+
 /* Assign the link group IDs to dentries in a link group table, and return the
  * next available link group ID. */
-u64 assign_link_groups(struct link_group_table *table)
+u64 assign_link_group_ids(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 (size_t i = 0; i < table->capacity; i++)
+		id = assign_link_group_ids_to_list(table->array[i], id);
+
+	/* Assign link group IDs to the "extra" link groups and insert them into
+	 * the hash table */
+	id = assign_link_group_ids_to_list(table->extra_groups, id);
+	insert_extra_groups(table);
+	return id;
+}
+
+
+
+static void inconsistent_link_group(const struct dentry *first_dentry)
+{
+	const struct dentry *dentry = first_dentry;
+
+	ERROR("An inconsistent hard link group that we cannot correct has been "
+	      "detected");
+	ERROR("The dentries are located at the following paths:");
+	do {
+		ERROR("`%s'", dentry->full_path_utf8);
+	} while ((dentry = container_of(dentry->link_group_list.next,
+				        struct dentry,
+					link_group_list)) != first_dentry);
+}
+
+static bool ref_dentries_consistent(const struct dentry * restrict ref_dentry_1,
+				    const struct dentry * restrict ref_dentry_2)
+{
+	wimlib_assert(ref_dentry_1 != ref_dentry_2);
+
+	if (ref_dentry_1->num_ads != ref_dentry_2->num_ads)
+		return false;
+	if (ref_dentry_1->security_id != ref_dentry_2->security_id
+	    || ref_dentry_1->attributes != ref_dentry_2->attributes)
+		return false;
+	for (unsigned i = 0; i <= ref_dentry_1->num_ads; i++) {
+		const u8 *ref_1_hash, *ref_2_hash;
+		ref_1_hash = dentry_stream_hash_unresolved(ref_dentry_1, i);
+		ref_2_hash = dentry_stream_hash_unresolved(ref_dentry_2, i);
+		if (!hashes_equal(ref_1_hash, ref_2_hash))
+			return false;
+		if (i && !ads_entries_have_same_name(&ref_dentry_1->ads_entries[i - 1],
+						     &ref_dentry_2->ads_entries[i - 1]))
+			return false;
+
+	}
+	return true;
+}
+
+static bool dentries_consistent(const struct dentry * restrict ref_dentry,
+				const struct dentry * restrict dentry)
+{
+	wimlib_assert(ref_dentry != dentry);
+
+	if (ref_dentry->num_ads != dentry->num_ads && dentry->num_ads != 0)
+		return false;
+	if (ref_dentry->security_id != dentry->security_id
+	    || ref_dentry->attributes != dentry->attributes)
+		return false;
+	for (unsigned i = 0; i <= min(ref_dentry->num_ads, dentry->num_ads); i++) {
+		const u8 *ref_hash, *hash;
+		ref_hash = dentry_stream_hash_unresolved(ref_dentry, i);
+		hash = dentry_stream_hash_unresolved(dentry, i);
+		if (!hashes_equal(ref_hash, hash) && !is_zero_hash(hash))
+			return false;
+		if (i && !ads_entries_have_same_name(&ref_dentry->ads_entries[i - 1],
+						     &dentry->ads_entries[i - 1]))
+			return false;
+	}
+	return true;
+}
+
+static int
+fix_true_link_group(struct dentry *first_dentry)
+{
+	struct dentry *dentry;
+	struct dentry *ref_dentry = NULL;
+	u64 last_ctime = 0;
+	u64 last_mtime = 0;
+	u64 last_atime = 0;
+
+	dentry = first_dentry;
+	do {
+		if (!ref_dentry || ref_dentry->num_ads == 0)
+			ref_dentry = dentry;
+		if (dentry->creation_time > last_ctime)
+			last_ctime = dentry->creation_time;
+		if (dentry->last_write_time > last_mtime)
+			last_mtime = dentry->last_write_time;
+		if (dentry->last_access_time > last_atime)
+			last_atime = dentry->last_access_time;
+	} while ((dentry = container_of(dentry->link_group_list.next,
+					struct dentry,
+					link_group_list)) != first_dentry);
+
+
+	ref_dentry->ads_entries_status = ADS_ENTRIES_OWNER;
+	dentry = first_dentry;
+	do {
+		if (dentry != ref_dentry) {
+			if (!dentries_consistent(ref_dentry, dentry)) {
+				inconsistent_link_group(first_dentry);
+				return WIMLIB_ERR_INVALID_DENTRY;
+			}
+			copy_hash(dentry->hash, ref_dentry->hash);
+			dentry_free_ads_entries(dentry);
+			dentry->num_ads            = ref_dentry->num_ads;
+			dentry->ads_entries        = ref_dentry->ads_entries;
+			dentry->ads_entries_status = ADS_ENTRIES_USER;
+		}
+		dentry->creation_time    = last_ctime;
+		dentry->last_write_time  = last_mtime;
+		dentry->last_access_time = last_atime;
+	} while ((dentry = container_of(dentry->link_group_list.next,
+					struct dentry,
+					link_group_list)) != first_dentry);
+	return 0;
+}
+
+static int
+fix_nominal_link_group(struct link_group *group,
+		       struct link_group **new_groups)
+{
+	struct dentry *tmp, *dentry, *ref_dentry;
+	int ret;
+	size_t num_true_link_groups;
+	struct list_head *head;
+	u64 link_group_id;
+
+	LIST_HEAD(dentries_with_data_streams);
+	LIST_HEAD(dentries_with_no_data_streams);
+	LIST_HEAD(true_link_groups);
+
+	/* Create the lists @dentries_with_data_streams and
+	 * @dentries_with_no_data_streams. */
+	dentry = container_of(group->dentry_list, struct dentry,
+			      link_group_list);
+	do {
+		for (unsigned i = 0; i <= dentry->num_ads; i++) {
+			const u8 *hash;
+			hash = dentry_stream_hash_unresolved(dentry, i);
+			if (!is_zero_hash(hash)) {
+				list_add(&dentry->tmp_list,
+					 &dentries_with_data_streams);
+				goto next_dentry;
+			}
+		}
+		list_add(&dentry->tmp_list,
+			 &dentries_with_no_data_streams);
+	next_dentry:
+		dentry = container_of(dentry->link_group_list.next,
+				      struct dentry,
+				      link_group_list);
+	} while (&dentry->link_group_list != group->dentry_list);
+
+	/* If there are no dentries with data streams, we require the nominal
+	 * link group to be a true link group */
+	if (list_empty(&dentries_with_data_streams))
+		return fix_true_link_group(container_of(group->dentry_list,
+							struct dentry,
+							link_group_list));
+
+	/* One or more dentries had data streams.  We check each of these
+	 * dentries for consistency with the others to form a set of true link
+	 * groups. */
+	num_true_link_groups = 0;
+	list_for_each_entry_safe(dentry, tmp, &dentries_with_data_streams,
+				 tmp_list)
+	{
+		list_del(&dentry->tmp_list);
+
+		/* Look for a true link group that is consistent with
+		 * this dentry and add this dentry to it.  Or, if none
+		 * of the true link groups are consistent with this
+		 * dentry, make a new one. */
+		list_for_each_entry(ref_dentry, &true_link_groups, tmp_list) {
+			if (ref_dentries_consistent(ref_dentry, dentry)) {
+				list_add(&dentry->link_group_list,
+					 &ref_dentry->link_group_list);
+				goto next_dentry_2;
+			}
+		}
+		num_true_link_groups++;
+		list_add(&dentry->tmp_list, &true_link_groups);
+		INIT_LIST_HEAD(&dentry->link_group_list);
+next_dentry_2:
+		;
+	}
+
+	wimlib_assert(num_true_link_groups != 0);
+
+	/* If there were dentries with no data streams, we require there to only
+	 * be one true link group so that we know which link group to assign the
+	 *
+	 * streamless dentries to. */
+	if (!list_empty(&dentries_with_no_data_streams)) {
+		if (num_true_link_groups != 1) {
+			ERROR("Hard link group ambiguity detected!");
+			ERROR("We split up hard link group 0x%"PRIx64" due to "
+			      "inconsistencies,");
+			ERROR("but dentries with no stream information remained. "
+			      "We don't know which true hard link");
+			ERROR("group to assign them to.");
+			return WIMLIB_ERR_INVALID_DENTRY;
+		}
+		ref_dentry = container_of(true_link_groups.next,
+					  struct dentry,
+					  tmp_list);
+		list_for_each_entry(dentry, &dentries_with_no_data_streams,
+				    tmp_list)
+		{
+			list_add(&dentry->link_group_list,
+				 &ref_dentry->link_group_list);
+		}
+	}
+
+	list_for_each_entry(dentry, &true_link_groups, tmp_list) {
+		ret = fix_true_link_group(dentry);
+		if (ret != 0)
+			return ret;
+	}
+
+	/* Make new `struct link_group's for the new link groups */
+	for (head = true_link_groups.next->next;
+	     head != &true_link_groups;
+	     head = head->next)
+	{
+		dentry = container_of(head, struct dentry, tmp_list);
+		group = MALLOC(sizeof(*group));
+		if (!group) {
+			ERROR("Out of memory");
+			return WIMLIB_ERR_NOMEM;
+		}
+		group->link_group_id = link_group_id;
+		group->dentry_list = &dentry->link_group_list;
+		group->next = *new_groups;
+		*new_groups = group;
+	} while ((head = head->next) != &true_link_groups);
+	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 fix_link_groups(struct link_group_table *table)
+{
 	for (u64 i = 0; i < table->capacity; i++) {
 		struct link_group *group = table->array[i];
-		struct link_group *next_group;
-		struct dentry *dentry;
 		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,
-						      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;
+			int ret;
+			ret = fix_nominal_link_group(group, &table->extra_groups);
+			if (ret != 0)
+				return ret;
+			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;
+	return 0;
+}
 
-		table->num_entries++;
-		group->next = table->array[pos];
-		table->array[pos] = group;
-		remaining_groups = remaining_groups->next;
+#if 0
+static bool dentries_have_same_ads(const struct dentry *d1,
+				   const struct dentry *d2)
+{
+	wimlib_assert(d1->num_ads == d2->num_ads);
+	/* 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 id;
+	return true;
 }
 
-#if 0
-/* Load a dentry tree into the link group table */
-int load_link_groups(struct link_group_table *table, struct dentry *root)
+/* 
+ * Share the alternate stream entries between hard-linked dentries.
+ *
+ * Notes:
+ * - If you use 'imagex.exe' (version 6.1.7600.16385) to create a WIM containing
+ *   hard-linked files, only one dentry in the hard link set will refer to data
+ *   streams, including all alternate data streams.  The rest of the dentries in
+ *   the hard link set will be marked as having 0 alternate data streams and
+ *   will not refer to any main file stream (the SHA1 message digest will be all
+ *   0's).
+ *
+ * - However, if you look at the WIM's that Microsoft actually distributes (e.g.
+ *   Windows 7/8 boot.wim, install.wim), it's not the same as above.  The
+ *   dentries in hard link sets will have stream information duplicated.  I
+ *   can't say anything about the alternate data streams because these WIMs do
+ *   not contain alternate data streams.
+ *
+ * - Windows 7 'install.wim' contains hard link sets containing dentries with
+ *   inconsistent streams and other inconsistent information such as security
+ *   ID.  The only way I can think to handle these is to treat the hard link
+ *   grouping as erroneous and split up the hard link group.
+ */
+static int share_dentry_ads(struct dentry *owner, struct dentry *user)
 {
-	int ret = for_dentry_in_tree(dentry, link_group_table_insert, table);
-	if (ret == 0)
-		assign_link_groups(table);
-	return ret;
+	const char *mismatch_type;
+	bool data_streams_shared = true;
+	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)) {
+		if (is_zero_hash(user->hash)) {
+			data_streams_shared = false;
+			copy_hash(user->hash, owner->hash);
+		} else {
+			mismatch_type = "main file resource";
+			goto mismatch;
+		}
+	}
+	if (data_streams_shared) {
+		if (!dentries_have_same_ads(owner, user)) {
+			mismatch_type = "Alternate Stream Entries";
+			goto mismatch;
+		}
+	}
+	if (owner->last_access_time != user->last_access_time
+	    || owner->last_write_time != user->last_write_time
+	    || owner->creation_time != user->creation_time) {
+	}
+	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' are supposedly 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;
 }
 #endif