[yocto] [meta-selinux][PATCHv2 7/8] e2fsprogs: Add stub functions for an xattr cache and struct to hold the header and block data.
Philip Tricca
flihp at twobit.us
Wed Jun 17 15:30:57 PDT 2015
Signed-off-by: Philip Tricca <flihp at twobit.us>
---
.../misc-xattr-create-xattr-block-node.patch | 175 +++++++++++++++++++++
.../e2fsprogs/e2fsprogs_1.42.9.bbappend | 1 +
2 files changed, 176 insertions(+)
create mode 100644 recipes-devtools/e2fsprogs/e2fsprogs/misc-xattr-create-xattr-block-node.patch
diff --git a/recipes-devtools/e2fsprogs/e2fsprogs/misc-xattr-create-xattr-block-node.patch b/recipes-devtools/e2fsprogs/e2fsprogs/misc-xattr-create-xattr-block-node.patch
new file mode 100644
index 0000000..f2e4582
--- /dev/null
+++ b/recipes-devtools/e2fsprogs/e2fsprogs/misc-xattr-create-xattr-block-node.patch
@@ -0,0 +1,175 @@
+Add two new functions to manage a cache of xattr blocks as well as a new struct
+to build a linked list of xattr blocks.
+
+xattr_add_block: Adds a block to the cache. This function is supplied with a
+pointer to the head of a linked list of xattr blocks and an xattr block to add.
+The purpose of this cache is to allow sharing of what would otherwise be
+duplicate xattr blocks and so duplicates are not allowed in this cache. If an
+identical block is already in the cache a pointer to this block will be
+returned.
+
+xattr_rm_block: Removes a block from the cache. This function is supplied with
+a pointer to the cache and a node that shall be removed from the cache. The
+cache is searched for the node and the node is removed if found.
+
+Both functions are integrated into the 'set_inode_xattr'. Here the logic is
+rearranged to cope with associating preexisting xattr blocks with inodes as
+well as creating new blocks when necessary.
+
+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
+@@ -25,6 +25,19 @@
+ #define XATTR_STDERR(fmt, args...) do {} while (0)
+ #endif
+
++/* nodes for simple linked list to track xattr blocks, calling it a cache
++ * would be a stretch ...
++ */
++typedef struct xattr_node xattr_node_t;
++
++struct xattr_node {
++ struct ext2_ext_attr_header *header;
++ blk_t block;
++ struct xattr_node *next;
++};
++
++xattr_node_t *xattr_list_head = NULL;
++
+ /* structure for mapping xattr name prefix data */
+ typedef struct xattr_prefix {
+ int index;
+@@ -48,6 +61,17 @@ xattr_prefix_t xattr_prefixes [] = {
+ { 0 },
+ };
+
++/* free xattr node and the buffer holding the xattr block */
++static void
++xattr_free_node (xattr_node_t *node)
++{
++ if (node) {
++ if (node->header)
++ free (node->header);
++ free (node);
++ }
++}
++
+ /* Free remaining resources after all files have been processed. */
+ void
+ xattr_cleanup ()
+@@ -260,6 +284,28 @@ out:
+ return ret;
+ }
+
++/* 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
++ * function will return a pointer to the pre-existing node.
++ */
++static xattr_node_t*
++xattr_add_block (xattr_node_t **head, xattr_node_t *node)
++{
++ XATTR_STDERR ("Adding xattr to the the node list.\n");
++ return node;
++}
++
++/* Remove xattr node from list. Returns pointer to the node being removed.
++ * NOTE: We're not comparing the xattr blocks, just the nodes.
++ */
++static xattr_node_t*
++xattr_rm_block (xattr_node_t **head, xattr_node_t *node)
++{
++ XATTR_STDERR ("Removing xattr from the node list.\n");
++ return node;
++}
++
+ /* This is the entry point to the xattr module. This function copies the xattrs
+ * from the file at 'path' to the file system object at 'ino'.
+ *
+@@ -274,16 +320,21 @@ set_inode_xattr (ext2_filsys fs, ext2_in
+ errcode_t ret = 0;
+ char *buf = NULL;
+ struct ext2_inode inode = { 0 };
+- blk_t block = 0;
+- struct ext2_ext_attr_header *header = NULL;
++ xattr_node_t *node = NULL, *node_tmp = NULL;
+ uint32_t newcount = 0;
+
+ XATTR_STDERR ("Copying xattrs from %s to inode 0x%x.\n", path, ino);
++ /* Create an xattr_node_t for it and add it to the cache if appropriate */
++ if (!(node = calloc (1, sizeof (xattr_node_t)))) {
++ com_err (__func__, errno, "calloc");
++ ret = errno;
++ goto out;
++ }
+ /* Populate the xattr block for the file at path */
+- if (ret = xattr_build_block (path, &header, fs->blocksize)) {
++ if (ret = xattr_build_block (path, &(node->header), fs->blocksize)) {
+ goto out;
+ }
+- if (header == NULL) {
++ if (node->header == NULL) {
+ XATTR_STDERR ("set_inode_xattrs: no xattrs for %s\n", path);
+ goto out;
+ }
+@@ -291,23 +342,38 @@ 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)) {
+- com_err(__func__, ret, "ext2fs_alloc_block: returned %d", ret);
++ if (!(node_tmp = xattr_add_block (&xattr_list_head, node))) {
++ fprintf (stderr, "Cannot add NULL node to xattr_block list.\n");
+ 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)) {
+- com_err(__func__, ret, "ext2fs_write_ext_attr: returned %d", ret);
+- goto out;
++ if (node == node_tmp) {
++ /* xattr block is new: add to list & write to disk */
++ XATTR_STDERR ("no pre-existing xattr block, creating / adding\n");
++ if (ret = ext2fs_alloc_block (fs, 0, NULL, &node->block)) {
++ com_err(__func__, ret, "ext2fs_alloc_block: returned %d", ret);
++ xattr_rm_block (&xattr_list_head, node);
++ goto out;
++ }
++ 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);
++ xattr_rm_block (&xattr_list_head, node);
++ goto out;
++ }
++ } else {
++ /* already have an identical xattr block, free the one we just made */
++ XATTR_STDERR ("using xattr from existing block: 0x%x\n", node_tmp->block);
++ xattr_free_node (node);
++ node = node_tmp;
+ }
+ /* 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))
+ {
+@@ -321,7 +387,6 @@ 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);
+ out:
+- if (header)
+- free (header);
++ 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 edc94d8..0705ec4 100644
--- a/recipes-devtools/e2fsprogs/e2fsprogs_1.42.9.bbappend
+++ b/recipes-devtools/e2fsprogs/e2fsprogs_1.42.9.bbappend
@@ -5,4 +5,5 @@ SRC_URI += " \
file://mke2fs.c-create_inode.c-copy-xattrs.patch \
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 \
"
--
2.1.4
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