[yocto] [meta-selinux][RFC 10/10] e2fsprogs: Add patch to implement simple linked list as cache for existing xattr blocks.
Philip Tricca
flihp at twobit.us
Sat Jun 6 17:37:08 PDT 2015
Signed-off-by: Philip Tricca <flihp at twobit.us>
---
.../e2fsprogs/misc-xattr-create-xattr-cache.patch | 217 +++++++++++++++++++++
.../e2fsprogs/e2fsprogs_1.42.9.bbappend | 1 +
2 files changed, 218 insertions(+)
create mode 100644 recipes-devtools/e2fsprogs/e2fsprogs/misc-xattr-create-xattr-cache.patch
diff --git a/recipes-devtools/e2fsprogs/e2fsprogs/misc-xattr-create-xattr-cache.patch b/recipes-devtools/e2fsprogs/e2fsprogs/misc-xattr-create-xattr-cache.patch
new file mode 100644
index 0000000..ba09e2b
--- /dev/null
+++ b/recipes-devtools/e2fsprogs/e2fsprogs/misc-xattr-create-xattr-cache.patch
@@ -0,0 +1,217 @@
+Implement the xattr block cache as a sorted linked list. This requires the add
+and rm functions be able to compare xattr blocks. This is implemented as two
+functions. The first compares individual entries and the second compares the
+whole xattr block by iterating over and comparing individual entries.
+
+The xattr block cache keeps memory allocated on the heap around across
+invocations of the set_inode_xattr function. To free this memory we implement
+an xattr_cleanup function that iterates over the cache freeing resources
+associated with each node.
+
+Signed-off-by: Philip Tricca <flihp at twobit.us>
+
+Index: e2fsprogs-1.42.9/misc/xattr.c
+===================================================================
+--- e2fsprogs-1.42.9.orig/misc/xattr.c
++++ e2fsprogs-1.42.9/misc/xattr.c
+@@ -76,7 +76,16 @@ xattr_free_node (xattr_node_t *node)
+ void
+ xattr_cleanup ()
+ {
++ xattr_node_t *curr = NULL, *tmp = NULL;
++ size_t count = 0;
++
+ XATTR_STDERR ("Cleaning up resources from xattrs.\n");
++ for (curr = xattr_list_head; curr != NULL; ++count) {
++ tmp = curr;
++ curr = curr->next;
++ xattr_free_node (tmp);
++ }
++ XATTR_STDERR ("Freed %d xattr_node_ts.\n", count);
+ }
+
+ /* Get value for named xattr from file at path.
+@@ -284,6 +293,77 @@ out:
+ return ret;
+ }
+
++/* Compre two extended attribute entries. This includes the entry and the value.
++ * if a < b return -1
++ * if a == b return 0
++ * if a > b return 1
++ */
++static int
++xattr_compare_entry (struct ext2_ext_attr_header *header_a,
++ struct ext2_ext_attr_entry *entry_a,
++ struct ext2_ext_attr_header *header_b,
++ struct ext2_ext_attr_entry *entry_b)
++{
++ int ret = 0;
++
++ if (entry_a->e_hash != entry_b->e_hash ||
++ entry_a->e_name_index != entry_b->e_name_index ||
++ entry_a->e_name_len != entry_b->e_name_len ||
++ entry_a->e_value_size != entry_b->e_value_size)
++ {
++ if (ret = memcmp (EXT2_EXT_ATTR_NAME(entry_a),
++ EXT2_EXT_ATTR_NAME(entry_b),
++ MIN (entry_a->e_name_len, entry_b->e_name_len)))
++ return ret;
++ if (entry_a->e_value_block != 0 || entry_b->e_value_block != 0)
++ return -EIO;
++ return memcmp (VALUE(header_a, entry_a),
++ VALUE(header_b, entry_b),
++ MIN(entry_a->e_value_size, entry_b->e_value_size));
++ }
++}
++
++/* Compare two extended attribute blocks. This includes the header as well as
++ * all entries and values.
++ * Algorithm is almost straight from the ext2 kernel drive with the exception
++ * of adding lt and gt behavior to get sorting.
++ * If a < b return < 0
++ * If a == b return 0
++ * If a > b return > 0
++ */
++static int
++xattr_compare_block (struct ext2_ext_attr_header *header_a,
++ struct ext2_ext_attr_header *header_b)
++{
++ struct ext2_ext_attr_entry *entry_a = NULL, *entry_b = NULL;
++ int ret = 0;
++
++ XATTR_STDERR ("comparing xattr blocks at 0x%x and 0x%x\n", header_a, header_b);
++ for (entry_a = FIRST_ENTRY(header_a), entry_b = FIRST_ENTRY(header_b);
++ !EXT2_EXT_IS_LAST_ENTRY(entry_a) && !EXT2_EXT_IS_LAST_ENTRY(entry_b);
++ entry_a = EXT2_EXT_ATTR_NEXT(entry_a), entry_b = EXT2_EXT_ATTR_NEXT(entry_b))
++ {
++ xattr_pp_value (VALUE(header_a, entry_a), entry_a->e_value_size);
++ xattr_pp_value (VALUE(header_b, entry_b), entry_b->e_value_size);
++ if (ret = xattr_compare_entry (header_a, entry_a, header_b, entry_b)) {
++ XATTR_STDERR ("entries do not match: %d\n", ret);
++ return ret;
++ } else {
++ XATTR_STDERR ("entries match!\n");
++ }
++ }
++ /* All entries checked were equal. Handle edge case where entry_a is a
++ * subset of entry_b: test to see if either block had more entries than the
++ * other. More entries -> block is greater than the other.
++ */
++ if (EXT2_EXT_IS_LAST_ENTRY(entry_a) && !EXT2_EXT_IS_LAST_ENTRY(entry_b))
++ return -1;
++ if (!EXT2_EXT_IS_LAST_ENTRY(entry_a) && EXT2_EXT_IS_LAST_ENTRY(entry_b))
++ return 1;
++ if (EXT2_EXT_IS_LAST_ENTRY(entry_a) && EXT2_EXT_IS_LAST_ENTRY(entry_b))
++ return 0;
++}
++
+ /* Add an xattr node to the list specified by head. This function will update
+ * head as necessary. It will return a pointer to the xattr_node_t added to the
+ * list. In the event that an identical xattr block is already on the list this
+@@ -292,7 +372,37 @@ out:
+ static xattr_node_t*
+ xattr_add_block (xattr_node_t **head, xattr_node_t *node)
+ {
++ xattr_node_t *curr_node = NULL, *prev_node = NULL;
++ int ret = 0;
++
+ XATTR_STDERR ("Adding xattr to the the node list.\n");
++ if (node == NULL)
++ return NULL;
++ /* list is empty, node becomes first node */
++ if (!(*head)) {
++ *head = node;
++ return node;
++ }
++ for (prev_node = NULL, curr_node = *head;
++ curr_node != NULL;
++ prev_node = curr_node, curr_node = curr_node->next)
++ {
++ /* When the supplied node is "less than" the current node we add it to
++ * the list before the current ndoe.
++ */
++ if ((ret = xattr_compare_block (node->header, curr_node->header)) < 0) {
++ node->next = curr_node;
++ if (prev_node)
++ prev_node->next = node;
++ else /* edge case: we added node to the head of the list */
++ *head = node;
++ return node;
++ } else if (ret == 0) { /* found a match */
++ return curr_node;
++ }
++ }
++ /* reached end of list, new node should be last */
++ prev_node->next = node;
+ return node;
+ }
+
+@@ -302,8 +412,27 @@ xattr_add_block (xattr_node_t **head, xa
+ static xattr_node_t*
+ xattr_rm_block (xattr_node_t **head, xattr_node_t *node)
+ {
++ xattr_node_t *curr_node = NULL, *prev_node = NULL;
++
+ XATTR_STDERR ("Removing xattr from the node list.\n");
+- return node;
++ /* no list, or empty list: nothing to search though */
++ if (!head || !(*head))
++ return NULL;
++
++ for (prev_node = NULL, curr_node = *head;
++ curr_node != NULL;
++ prev_node = curr_node, curr_node = curr_node->next)
++ {
++ if (node == curr_node) {
++ if (prev_node)
++ prev_node->next = curr_node->next;
++ else
++ *head = curr_node->next;
++ return curr_node;
++ }
++ }
++ /* reached end of list, no match */
++ return NULL;
+ }
+
+ /* This is the entry point to the xattr module. This function copies the xattrs
+@@ -342,23 +471,23 @@ set_inode_xattr (ext2_filsys fs, ext2_in
+ com_err(__func__, ret, "ext2fs_read_inode");
+ goto out;
+ }
+- if (ret = ext2fs_alloc_block (fs, 0, NULL, &block)) {
++ if (ret = ext2fs_alloc_block (fs, 0, NULL, &(node->block))) {
+ com_err(__func__, ret, "ext2fs_alloc_block: returned %d", ret);
+ goto out;
+ }
+- ext2fs_mark_block_bitmap2 (fs->block_map, block);
+- XATTR_STDERR ("writing xattr block 0x%x to disk:\n", block);
+- if (ret = ext2fs_write_ext_attr (fs, block, header)) {
++ ext2fs_mark_block_bitmap2 (fs->block_map, node->block);
++ XATTR_STDERR ("writing xattr block 0x%x to disk:\n", node->block);
++ if (ret = ext2fs_write_ext_attr (fs, node->block, node->header)) {
+ com_err(__func__, ret, "ext2fs_write_ext_attr: returned %d", ret);
+ goto out;
+ }
+ /* point inode for current file to xattr block, update block count and
+ * write inode to disk
+ */
+- inode.i_file_acl = block;
++ inode.i_file_acl = node->block;
+ if (ret = ext2fs_adjust_ea_refcount2(fs,
+- block,
+- (char*)header,
++ node->block,
++ (char*)(node->header),
+ 1,
+ &newcount))
+ {
+@@ -371,6 +500,7 @@ set_inode_xattr (ext2_filsys fs, ext2_in
+ }
+ if (ret = ext2fs_write_inode (fs, ino, &inode))
+ com_err(__func__, ret, "ext2fs_write_inode: returned %d", ret);
++ return ret;
+ out:
+ xattr_free_node (node);
+ return ret;
diff --git a/recipes-devtools/e2fsprogs/e2fsprogs_1.42.9.bbappend b/recipes-devtools/e2fsprogs/e2fsprogs_1.42.9.bbappend
index 241a9bf..8756d76 100644
--- a/recipes-devtools/e2fsprogs/e2fsprogs_1.42.9.bbappend
+++ b/recipes-devtools/e2fsprogs/e2fsprogs_1.42.9.bbappend
@@ -8,4 +8,5 @@ SRC_URI += " \
file://lib-ext2fs-ext2_ext_attr.h-add-xattr-index.patch \
file://misc-xattr-create-xattr-block.patch \
file://misc-xattr-create-xattr-block-node.patch \
+ file://misc-xattr-create-xattr-cache.patch \
"
--
2.1.4
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