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Message-ID: <4D0A5412.1040600@gmail.com>
Date: Thu, 16 Dec 2010 19:01:54 +0100
From: Marco Stornelli <marco.stornelli@...il.com>
To: Linux Kernel <linux-kernel@...r.kernel.org>
CC: Linux Embedded <linux-embedded@...r.kernel.org>,
Linux FS Devel <linux-fsdevel@...r.kernel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Tim Bird <tim.bird@...sony.com>
Subject: [PATCH 12/16 v5] pramfs: extended attributes management
From: Marco Stornelli <marco.stornelli@...il.com>
Extended attributes operations.
Signed-off-by: Marco Stornelli <marco.stornelli@...il.com>
---
diff -Nurp linux-2.6.36-orig/fs/pramfs/xattr.c linux-2.6.36/fs/pramfs/xattr.c
--- linux-2.6.36-orig/fs/pramfs/xattr.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.36/fs/pramfs/xattr.c 2010-11-28 17:51:11.000000000 +0100
@@ -0,0 +1,1104 @@
+/*
+ * BRIEF DESCRIPTION
+ *
+ * Extended attributes operations.
+ *
+ * Copyright 2010 Marco Stornelli <marco.stornelli@...il.com>
+ *
+ * based on fs/ext2/xattr.c with the following copyright:
+ *
+ * Fix by Harrison Xing <harrison@...ntainviewdata.com>.
+ * Extended attributes for symlinks and special files added per
+ * suggestion of Luka Renko <luka.renko@...mes.si>.
+ * xattr consolidation Copyright (c) 2004 James Morris <jmorris@...hat.com>,
+ * Red Hat Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+/*
+ * Extended attributes are stored in blocks allocated outside of
+ * any inode. The i_xattr field is then made to point to this allocated
+ * block. If all extended attributes of an inode are identical, these
+ * inodes may share the same extended attribute block. Such situations
+ * are automatically detected by keeping a cache of recent attribute block
+ * numbers and hashes over the block's contents in memory.
+ *
+ *
+ * Extended attribute block layout:
+ *
+ * +------------------+
+ * | header |
+ * | entry 1 | |
+ * | entry 2 | | growing downwards
+ * | entry 3 | v
+ * | four null bytes |
+ * | . . . |
+ * | value 1 | ^
+ * | value 3 | | growing upwards
+ * | value 2 | |
+ * +------------------+
+ *
+ * The block header is followed by multiple entry descriptors. These entry
+ * descriptors are variable in size, and alligned to PRAM_XATTR_PAD
+ * byte boundaries. The entry descriptors are sorted by attribute name,
+ * so that two extended attribute blocks can be compared efficiently.
+ *
+ * Attribute values are aligned to the end of the block, stored in
+ * no specific order. They are also padded to PRAM_XATTR_PAD byte
+ * boundaries. No additional gaps are left between them.
+ *
+ * Locking strategy
+ * ----------------
+ * pi->i_xattr is protected by PRAM_I(inode)->xattr_sem.
+ * EA blocks are only changed if they are exclusive to an inode, so
+ * holding xattr_sem also means that nothing but the EA block's reference
+ * count will change. Multiple writers to an EA block are synchronized
+ * by the mutex in each block descriptor. Block descriptors are kept in a
+ * red black tree and the key is the absolute block number.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/mbcache.h>
+#include <linux/rwsem.h>
+#include <linux/security.h>
+#include "pram.h"
+#include "xattr.h"
+#include "acl.h"
+#include "desctree.h"
+
+#define HDR(bp) ((struct pram_xattr_header *)(bp))
+#define ENTRY(ptr) ((struct pram_xattr_entry *)(ptr))
+#define FIRST_ENTRY(bh) ENTRY(HDR(bh)+1)
+#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
+#define GET_DESC(sbi, blocknr) lookup_xblock_desc(sbi, blocknr, pram_xblock_desc_cache, 1)
+#define LOOKUP_DESC(sbi, blocknr) lookup_xblock_desc(sbi, blocknr, NULL, 0)
+
+#ifdef PRAM_XATTR_DEBUG
+# define ea_idebug(inode, f...) do { \
+ printk(KERN_DEBUG "inode %ld: ", inode->i_ino); \
+ printk(f); \
+ printk("\n"); \
+ } while (0)
+# define ea_bdebug(blocknr, f...) do { \
+ printk(KERN_DEBUG "block %lu: ", blocknr); \
+ printk(f); \
+ printk("\n"); \
+ } while (0)
+#else
+# define ea_idebug(f...)
+# define ea_bdebug(f...)
+#endif
+
+static int pram_xattr_set2(struct inode *, char *, struct pram_xblock_desc *, struct pram_xattr_header *);
+
+static int pram_xattr_cache_insert(struct super_block *sb, unsigned long blocknr, u32 xhash);
+static struct pram_xblock_desc *pram_xattr_cache_find(struct inode *,
+ struct pram_xattr_header *);
+static void pram_xattr_rehash(struct pram_xattr_header *,
+ struct pram_xattr_entry *);
+
+static struct mb_cache *pram_xattr_cache;
+static struct kmem_cache *pram_xblock_desc_cache;
+
+static const struct xattr_handler *pram_xattr_handler_map[] = {
+ [PRAM_XATTR_INDEX_USER] = &pram_xattr_user_handler,
+#ifdef CONFIG_PRAMFS_POSIX_ACL
+ [PRAM_XATTR_INDEX_POSIX_ACL_ACCESS] = &pram_xattr_acl_access_handler,
+ [PRAM_XATTR_INDEX_POSIX_ACL_DEFAULT] = &pram_xattr_acl_default_handler,
+#endif
+ [PRAM_XATTR_INDEX_TRUSTED] = &pram_xattr_trusted_handler,
+#ifdef CONFIG_PRAMFS_SECURITY
+ [PRAM_XATTR_INDEX_SECURITY] = &pram_xattr_security_handler,
+#endif
+};
+
+const struct xattr_handler *pram_xattr_handlers[] = {
+ &pram_xattr_user_handler,
+ &pram_xattr_trusted_handler,
+#ifdef CONFIG_PRAMFS_POSIX_ACL
+ &pram_xattr_acl_access_handler,
+ &pram_xattr_acl_default_handler,
+#endif
+#ifdef CONFIG_PRAMFS_SECURITY
+ &pram_xattr_security_handler,
+#endif
+ NULL
+};
+
+static void desc_put(struct super_block *sb, struct pram_xblock_desc *desc)
+{
+ struct pram_sb_info *sbi = (struct pram_sb_info *)sb->s_fs_info;
+ if (!put_xblock_desc(sbi, desc)) {
+ /* Ok we can free the block and its descriptor */
+ pram_dbg("freeing block %lu and its descriptor", desc->blocknr);
+ pram_free_block(sb, desc->blocknr);
+ kmem_cache_free(pram_xblock_desc_cache, desc);
+ }
+}
+
+static inline const struct xattr_handler *pram_xattr_handler(int name_index)
+{
+ const struct xattr_handler *handler = NULL;
+
+ if (name_index > 0 && name_index < ARRAY_SIZE(pram_xattr_handler_map))
+ handler = pram_xattr_handler_map[name_index];
+ return handler;
+}
+
+/*
+ * pram_xattr_get()
+ *
+ * Copy an extended attribute into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+int pram_xattr_get(struct inode *inode, int name_index, const char *name,
+ void *buffer, size_t buffer_size)
+{
+ char *bp = NULL;
+ struct pram_xattr_entry *entry;
+ struct pram_xblock_desc *desc;
+ struct pram_inode *pi;
+ size_t name_len, size;
+ char *end;
+ int error = 0;
+ unsigned long blocknr;
+ struct super_block *sb = inode->i_sb;
+ struct pram_sb_info *sbi = (struct pram_sb_info *)sb->s_fs_info;
+
+ ea_idebug(inode, "name=%d<%s>, buffer=%p, buffer_size=%ld",
+ name_index, name, buffer, (long)buffer_size);
+
+ pi = pram_get_inode(sb, inode->i_ino);
+ if (!pi)
+ return -EINVAL;
+ if (name == NULL)
+ return -EINVAL;
+ down_read(&PRAM_I(inode)->xattr_sem);
+ error = -ENODATA;
+ if (!pi->i_xattr)
+ goto cleanup;
+ ea_idebug(inode, "reading block %llu", be64_to_cpu(pi->i_xattr));
+ bp = pram_get_block(sb, be64_to_cpu(pi->i_xattr));
+ error = -EIO;
+ if (!bp)
+ goto cleanup;
+ end = bp + sb->s_blocksize;
+ blocknr = pram_get_blocknr(sb, be64_to_cpu(pi->i_xattr));
+ ea_bdebug(blocknr, "refcount=%d", be32_to_cpu(HDR(bp)->h_refcount));
+ if (HDR(bp)->h_magic != cpu_to_be32(PRAM_XATTR_MAGIC)) {
+bad_block: pram_err(sb, "inode %ld: bad block %llu", inode->i_ino,
+ be64_to_cpu(pi->i_xattr));
+ error = -EIO;
+ goto cleanup;
+ }
+ /* find named attribute */
+ name_len = strlen(name);
+
+ error = -ERANGE;
+ if (name_len > 255)
+ goto cleanup;
+ entry = FIRST_ENTRY(bp);
+ while (!IS_LAST_ENTRY(entry)) {
+ struct pram_xattr_entry *next =
+ PRAM_XATTR_NEXT(entry);
+ if ((char *)next >= end)
+ goto bad_block;
+ if (name_index == entry->e_name_index &&
+ name_len == entry->e_name_len &&
+ memcmp(name, entry->e_name, name_len) == 0)
+ goto found;
+ entry = next;
+ }
+ /* Check the remaining name entries */
+ while (!IS_LAST_ENTRY(entry)) {
+ struct pram_xattr_entry *next =
+ PRAM_XATTR_NEXT(entry);
+ if ((char *)next >= end)
+ goto bad_block;
+ entry = next;
+ }
+
+ desc = GET_DESC(sbi, blocknr);
+ if (IS_ERR(desc)) {
+ error = -ENOMEM;
+ goto cleanup;
+ }
+ desc_put(sb, desc);
+ if (pram_xattr_cache_insert(sb, blocknr,
+ be32_to_cpu(HDR(bp)->h_hash)))
+ ea_idebug(inode, "cache insert failed");
+ error = -ENODATA;
+ goto cleanup;
+found:
+ /* check the buffer size */
+ if (entry->e_value_block != 0)
+ goto bad_block;
+ size = be32_to_cpu(entry->e_value_size);
+ if (size > inode->i_sb->s_blocksize ||
+ be16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize)
+ goto bad_block;
+
+ desc = GET_DESC(sbi, blocknr);
+ if (IS_ERR(desc)) {
+ error = -ENOMEM;
+ goto cleanup;
+ }
+ desc_put(sb, desc);
+ if (pram_xattr_cache_insert(sb, blocknr,
+ be32_to_cpu(HDR(bp)->h_hash)))
+ ea_idebug(inode, "cache insert failed");
+ if (buffer) {
+ error = -ERANGE;
+ if (size > buffer_size)
+ goto cleanup;
+ /* return value of attribute */
+ memcpy(buffer, bp + be16_to_cpu(entry->e_value_offs),
+ size);
+ }
+ error = size;
+
+cleanup:
+ up_read(&PRAM_I(inode)->xattr_sem);
+
+ return error;
+}
+
+/*
+ * pram_xattr_list()
+ *
+ * Copy a list of attribute names into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+static int pram_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+ struct inode *inode = dentry->d_inode;
+ char *bp = NULL;
+ struct pram_xattr_entry *entry;
+ struct pram_xblock_desc *desc;
+ struct pram_inode *pi;
+ char *end;
+ size_t rest = buffer_size;
+ int error = 0;
+ unsigned long blocknr;
+ struct super_block *sb = inode->i_sb;
+ struct pram_sb_info *sbi = (struct pram_sb_info *)sb->s_fs_info;
+
+ ea_idebug(inode, "buffer=%p, buffer_size=%ld",
+ buffer, (long)buffer_size);
+
+ pi = pram_get_inode(sb, inode->i_ino);
+ if (!pi)
+ return error;
+ down_read(&PRAM_I(inode)->xattr_sem);
+ error = 0;
+ if (!pi->i_xattr)
+ goto cleanup;
+ ea_idebug(inode, "reading block %llu", be64_to_cpu(pi->i_xattr));
+ bp = pram_get_block(sb, be64_to_cpu(pi->i_xattr));
+ blocknr = pram_get_blocknr(sb, be64_to_cpu(pi->i_xattr));
+ error = -EIO;
+ if (!bp)
+ goto cleanup;
+ ea_bdebug(blocknr, "refcount=%d", be32_to_cpu(HDR(bp)->h_refcount));
+ end = bp + sb->s_blocksize;
+ if (HDR(bp)->h_magic != cpu_to_be32(PRAM_XATTR_MAGIC)) {
+bad_block: pram_err(sb, "inode %ld: bad block %llu", inode->i_ino,
+ be64_to_cpu(pi->i_xattr));
+ error = -EIO;
+ goto cleanup;
+ }
+
+ /* check the on-disk data structure */
+ entry = FIRST_ENTRY(bp);
+ while (!IS_LAST_ENTRY(entry)) {
+ struct pram_xattr_entry *next = PRAM_XATTR_NEXT(entry);
+
+ if ((char *)next >= end)
+ goto bad_block;
+ entry = next;
+ }
+
+ desc = GET_DESC(sbi, blocknr);
+ if (IS_ERR(desc)) {
+ error = -ENOMEM;
+ goto cleanup;
+ }
+ desc_put(sb, desc);
+ if (pram_xattr_cache_insert(sb, blocknr,
+ be32_to_cpu(HDR(bp)->h_hash)))
+ ea_idebug(inode, "cache insert failed");
+
+ /* list the attribute names */
+ for (entry = FIRST_ENTRY(bp); !IS_LAST_ENTRY(entry);
+ entry = PRAM_XATTR_NEXT(entry)) {
+ const struct xattr_handler *handler =
+ pram_xattr_handler(entry->e_name_index);
+
+ if (handler) {
+ size_t size = handler->list(dentry, buffer, rest,
+ entry->e_name,
+ entry->e_name_len,
+ handler->flags);
+ if (buffer) {
+ if (size > rest) {
+ error = -ERANGE;
+ goto cleanup;
+ }
+ buffer += size;
+ }
+ rest -= size;
+ }
+ }
+ error = buffer_size - rest; /* total size */
+
+cleanup:
+ up_read(&PRAM_I(inode)->xattr_sem);
+
+ return error;
+}
+
+/*
+ * Inode operation listxattr()
+ *
+ * dentry->d_inode->i_mutex: don't care
+ */
+ssize_t pram_listxattr(struct dentry *dentry, char *buffer, size_t size)
+{
+ return pram_xattr_list(dentry, buffer, size);
+}
+
+/*
+ * pram_xattr_set()
+ *
+ * Create, replace or remove an extended attribute for this inode. Buffer
+ * is NULL to remove an existing extended attribute, and non-NULL to
+ * either replace an existing extended attribute, or create a new extended
+ * attribute. The flags XATTR_REPLACE and XATTR_CREATE
+ * specify that an extended attribute must exist and must not exist
+ * previous to the call, respectively.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int pram_xattr_set(struct inode *inode, int name_index, const char *name,
+ const void *value, size_t value_len, int flags)
+{
+ struct super_block *sb = inode->i_sb;
+ struct pram_sb_info *sbi = (struct pram_sb_info *)sb->s_fs_info;
+ struct pram_xattr_header *header = NULL;
+ struct pram_xattr_entry *here, *last;
+ struct pram_inode *pi;
+ struct pram_xblock_desc *desc = NULL;
+ size_t name_len, free, min_offs = sb->s_blocksize;
+ int not_found = 1, error;
+ char *end;
+ char *bp = NULL;
+ unsigned long blocknr = 0;
+
+ /*
+ * header -- Points either into bp, or to a temporarily
+ * allocated buffer.
+ * here -- The named entry found, or the place for inserting, within
+ * the block pointed to by header.
+ * last -- Points right after the last named entry within the block
+ * pointed to by header.
+ * min_offs -- The offset of the first value (values are aligned
+ * towards the end of the block).
+ * end -- Points right after the block pointed to by header.
+ */
+
+ ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
+ name_index, name, value, (long)value_len);
+
+ if (value == NULL)
+ value_len = 0;
+ if (name == NULL)
+ return -EINVAL;
+ name_len = strlen(name);
+ if (name_len > 255 || value_len > sb->s_blocksize)
+ return -ERANGE;
+ pi = pram_get_inode(sb, inode->i_ino);
+ if (!pi)
+ return -EINVAL;
+ down_write(&PRAM_I(inode)->xattr_sem);
+ if (pi->i_xattr) {
+ /* The inode already has an extended attribute block. */
+ bp = pram_get_block(sb, be64_to_cpu(pi->i_xattr));
+ error = -EIO;
+ if (!bp)
+ goto cleanup;
+ blocknr = pram_get_blocknr(sb, be64_to_cpu(pi->i_xattr));
+ ea_bdebug(blocknr, "refcount=%d", be32_to_cpu(HDR(bp)->h_refcount));
+ header = HDR(bp);
+ end = bp + sb->s_blocksize;
+ if (header->h_magic != cpu_to_be32(PRAM_XATTR_MAGIC)) {
+bad_block: pram_err(sb, "inode %ld: bad block %llu", inode->i_ino,
+ be64_to_cpu(pi->i_xattr));
+ error = -EIO;
+ goto cleanup;
+ }
+ /* Find the named attribute. */
+ here = FIRST_ENTRY(bp);
+ while (!IS_LAST_ENTRY(here)) {
+ struct pram_xattr_entry *next = PRAM_XATTR_NEXT(here);
+ if ((char *)next >= end)
+ goto bad_block;
+ if (!here->e_value_block && here->e_value_size) {
+ size_t offs = be16_to_cpu(here->e_value_offs);
+ if (offs < min_offs)
+ min_offs = offs;
+ }
+ not_found = name_index - here->e_name_index;
+ if (!not_found)
+ not_found = name_len - here->e_name_len;
+ if (!not_found)
+ not_found = memcmp(name, here->e_name, name_len);
+ if (not_found <= 0)
+ break;
+ here = next;
+ }
+ last = here;
+ /* We still need to compute min_offs and last. */
+ while (!IS_LAST_ENTRY(last)) {
+ struct pram_xattr_entry *next = PRAM_XATTR_NEXT(last);
+ if ((char *)next >= end)
+ goto bad_block;
+ if (!last->e_value_block && last->e_value_size) {
+ size_t offs = be16_to_cpu(last->e_value_offs);
+ if (offs < min_offs)
+ min_offs = offs;
+ }
+ last = next;
+ }
+
+ /* Check whether we have enough space left. */
+ free = min_offs - ((char *)last - (char *)header) - sizeof(__u32);
+ } else {
+ /* We will use a new extended attribute block. */
+ free = sb->s_blocksize -
+ sizeof(struct pram_xattr_header) - sizeof(__u32);
+ here = last = NULL; /* avoid gcc uninitialized warning. */
+ }
+
+ if (not_found) {
+ /* Request to remove a nonexistent attribute? */
+ error = -ENODATA;
+ if (flags & XATTR_REPLACE)
+ goto cleanup;
+ error = 0;
+ if (value == NULL)
+ goto cleanup;
+ } else {
+ /* Request to create an existing attribute? */
+ error = -EEXIST;
+ if (flags & XATTR_CREATE)
+ goto cleanup;
+ if (!here->e_value_block && here->e_value_size) {
+ size_t size = be32_to_cpu(here->e_value_size);
+
+ if (be16_to_cpu(here->e_value_offs) + size >
+ sb->s_blocksize || size > sb->s_blocksize)
+ goto bad_block;
+ free += PRAM_XATTR_SIZE(size);
+ }
+ free += PRAM_XATTR_LEN(name_len);
+ }
+ error = -ENOSPC;
+ if (free < PRAM_XATTR_LEN(name_len) + PRAM_XATTR_SIZE(value_len))
+ goto cleanup;
+
+ /* Here we know that we can set the new attribute. */
+
+ if (header) {
+ struct mb_cache_entry *ce;
+
+ desc = GET_DESC(sbi, blocknr);
+ if (IS_ERR(desc)) {
+ error = -ENOMEM;
+ goto cleanup;
+ }
+
+ /* assert(header == HDR(bp)); */
+ ce = mb_cache_entry_get(pram_xattr_cache, (struct block_device *)sbi,
+ blocknr);
+ mutex_lock(&desc->lock);
+ pram_memunlock_block(sb, bp);
+ if (header->h_refcount == cpu_to_be32(1)) {
+ ea_bdebug(blocknr, "modifying in-place");
+ if (ce)
+ mb_cache_entry_free(ce);
+ /* keep it locked while modifying it. */
+ } else {
+ int offset;
+
+ if (ce)
+ mb_cache_entry_release(ce);
+ pram_memlock_block(sb, bp);
+ mutex_unlock(&desc->lock);
+ ea_bdebug(desc->blocknr, "cloning");
+ header = kmalloc(inode->i_sb->s_blocksize, GFP_KERNEL);
+ error = -ENOMEM;
+ if (header == NULL)
+ goto cleanup;
+ memcpy(header, HDR(bp), inode->i_sb->s_blocksize);
+ header->h_refcount = cpu_to_be32(1);
+
+ offset = (char *)here - bp;
+ here = ENTRY((char *)header + offset);
+ offset = (char *)last - bp;
+ last = ENTRY((char *)header + offset);
+ }
+ } else {
+ /* Allocate a buffer where we construct the new block. */
+ header = kzalloc(sb->s_blocksize, GFP_KERNEL);
+ error = -ENOMEM;
+ if (header == NULL)
+ goto cleanup;
+ end = (char *)header + sb->s_blocksize;
+ header->h_magic = cpu_to_be32(PRAM_XATTR_MAGIC);
+ header->h_refcount = cpu_to_be32(1);
+ last = here = ENTRY(header+1);
+ }
+
+ /* Iff we are modifying the block in-place, the block is locked here. */
+
+ if (not_found) {
+ /* Insert the new name. */
+ size_t size = PRAM_XATTR_LEN(name_len);
+ size_t rest = (char *)last - (char *)here;
+ memmove((char *)here + size, here, rest);
+ memset(here, 0, size);
+ here->e_name_index = name_index;
+ here->e_name_len = name_len;
+ memcpy(here->e_name, name, name_len);
+ } else {
+ if (!here->e_value_block && here->e_value_size) {
+ char *first_val = (char *)header + min_offs;
+ size_t offs = be16_to_cpu(here->e_value_offs);
+ char *val = (char *)header + offs;
+ size_t size = PRAM_XATTR_SIZE(
+ be32_to_cpu(here->e_value_size));
+
+ if (size == PRAM_XATTR_SIZE(value_len)) {
+ /* The old and the new value have the same
+ size. Just replace. */
+ here->e_value_size = cpu_to_be32(value_len);
+ memset(val + size - PRAM_XATTR_PAD, 0,
+ PRAM_XATTR_PAD); /* Clear pad bytes. */
+ memcpy(val, value, value_len);
+ goto skip_replace;
+ }
+
+ /* Remove the old value. */
+ memmove(first_val + size, first_val, val - first_val);
+ memset(first_val, 0, size);
+ here->e_value_offs = 0;
+ min_offs += size;
+
+ /* Adjust all value offsets. */
+ last = ENTRY(header+1);
+ while (!IS_LAST_ENTRY(last)) {
+ size_t o = be16_to_cpu(last->e_value_offs);
+ if (!last->e_value_block && o < offs)
+ last->e_value_offs =
+ cpu_to_be16(o + size);
+ last = PRAM_XATTR_NEXT(last);
+ }
+ }
+ if (value == NULL) {
+ /* Remove the old name. */
+ size_t size = PRAM_XATTR_LEN(name_len);
+ last = ENTRY((char *)last - size);
+ memmove(here, (char *)here + size,
+ (char *)last - (char *)here);
+ memset(last, 0, size);
+ }
+ }
+
+ if (value != NULL) {
+ /* Insert the new value. */
+ here->e_value_size = cpu_to_be32(value_len);
+ if (value_len) {
+ size_t size = PRAM_XATTR_SIZE(value_len);
+ char *val = (char *)header + min_offs - size;
+ here->e_value_offs =
+ cpu_to_be16((char *)val - (char *)header);
+ memset(val + size - PRAM_XATTR_PAD, 0,
+ PRAM_XATTR_PAD); /* Clear the pad bytes. */
+ memcpy(val, value, value_len);
+ }
+ }
+
+skip_replace:
+ if (IS_LAST_ENTRY(ENTRY(header+1))) {
+ /* This block is now empty. */
+ if (bp && header == HDR(bp)) {
+ /* we were modifying in-place. */
+ pram_memlock_block(sb, bp);
+ mutex_unlock(&desc->lock);
+ }
+ error = pram_xattr_set2(inode, bp, desc, NULL);
+ } else {
+ pram_xattr_rehash(header, here);
+ if (bp && header == HDR(bp)) {
+ /* we were modifying in-place. */
+ pram_memlock_block(sb, bp);
+ mutex_unlock(&desc->lock);
+ }
+ error = pram_xattr_set2(inode, bp, desc, header);
+ }
+
+cleanup:
+ desc_put(sb, desc);
+ if (!(bp && header == HDR(bp)))
+ kfree(header);
+ up_write(&PRAM_I(inode)->xattr_sem);
+
+ return error;
+}
+
+/*
+ * Second half of pram_xattr_set(): Update the file system.
+ */
+static int pram_xattr_set2(struct inode *inode, char *old_bp,
+ struct pram_xblock_desc *old_desc,
+ struct pram_xattr_header *header)
+{
+ struct super_block *sb = inode->i_sb;
+ struct pram_sb_info *sbi = (struct pram_sb_info *)sb->s_fs_info;
+ struct pram_xblock_desc *new_desc = NULL;
+ unsigned long blocknr;
+ struct pram_inode *pi;
+ int error;
+ char *new_bp = NULL;
+
+ if (header) {
+ new_desc = pram_xattr_cache_find(inode, header);
+ if (new_desc) {
+ new_bp = pram_get_block(sb, pram_get_block_off(sb, new_desc->blocknr));
+ /* We found an identical block in the cache. */
+ if (new_bp == old_bp) {
+ ea_bdebug(new_desc->blocknr, "keeping this block");
+ } else {
+ /* The old block is released after updating
+ the inode. */
+ ea_bdebug(new_desc->blocknr, "reusing block");
+ pram_memunlock_block(sb, new_bp);
+ be32_add_cpu(&HDR(new_bp)->h_refcount, 1);
+ pram_memlock_block(sb, new_bp);
+ ea_bdebug(new_desc->blocknr, "refcount now=%d",
+ be32_to_cpu(HDR(new_bp)->h_refcount));
+ }
+ blocknr = new_desc->blocknr;
+ mutex_unlock(&new_desc->lock);
+ desc_put(sb, new_desc);
+ } else if (old_bp && header == HDR(old_bp)) {
+ /* Keep this block. No need to lock the block as we
+ don't need to change the reference count. */
+ new_bp = old_bp;
+ pram_xattr_cache_insert(sb, old_desc->blocknr, HDR(new_bp)->h_hash);
+ blocknr = old_desc->blocknr;
+ } else {
+ /* We need to allocate a new block */
+ struct pram_xblock_desc *new_desc;
+
+ error = pram_new_block(sb, &blocknr, 1);
+ if (error)
+ goto out;
+ ea_idebug(inode, "creating block %lu", blocknr);
+ new_desc = kmem_cache_alloc(pram_xblock_desc_cache, GFP_KERNEL);
+ if (!new_desc) {
+ pram_free_block(sb, blocknr);
+ error = -EIO;
+ goto out;
+ }
+ xblock_desc_init_always(new_desc);
+ new_desc->blocknr = blocknr;
+ new_bp = pram_get_block(sb, pram_get_block_off(sb, blocknr));
+ if (!new_bp) {
+ pram_free_block(sb, blocknr);
+ kmem_cache_free(pram_xblock_desc_cache, new_desc);
+ error = -EIO;
+ goto out;
+ }
+ pram_memunlock_block(sb, new_bp);
+ memcpy(new_bp, header, sb->s_blocksize);
+ pram_memlock_block(sb, new_bp);
+ insert_xblock_desc(sbi, new_desc);
+ pram_xattr_cache_insert(sb, new_desc->blocknr, HDR(new_bp)->h_hash);
+ }
+ }
+
+ /* Update the inode. */
+ pi = pram_get_inode(sb, inode->i_ino);
+ pram_memunlock_inode(sb, pi);
+ pi->i_xattr = new_bp ? be64_to_cpu(pram_get_block_off(sb, blocknr)) : 0;
+ inode->i_ctime = CURRENT_TIME_SEC;
+ pi->i_ctime = cpu_to_be32(inode->i_ctime.tv_sec);
+ pram_memlock_inode(sb, pi);
+
+ error = 0;
+ if (old_bp && old_bp != new_bp) {
+ struct mb_cache_entry *ce;
+
+ /* Here old_desc MUST be valid or we have a bug */
+ BUG_ON(!old_desc);
+
+ /*
+ * If there was an old block and we are no longer using it,
+ * release the old block.
+ */
+ ce = mb_cache_entry_get(pram_xattr_cache, (struct block_device *)sbi,
+ old_desc->blocknr);
+ mutex_lock(&old_desc->lock);
+ if (HDR(old_bp)->h_refcount == cpu_to_be32(1)) {
+ /* Free the old block. */
+ if (ce)
+ mb_cache_entry_free(ce);
+ ea_bdebug(old_desc->blocknr, "freeing");
+ mutex_unlock(&old_desc->lock);
+ /* Caller will call desc_put later */
+ mark_free_desc(old_desc);
+ } else {
+ /* Decrement the refcount only. */
+ pram_memunlock_block(sb, old_bp);
+ be32_add_cpu(&HDR(old_bp)->h_refcount, -1);
+ pram_memlock_block(sb, old_bp);
+ if (ce)
+ mb_cache_entry_release(ce);
+ ea_bdebug(old_desc->blocknr, "refcount now=%d",
+ be32_to_cpu(HDR(old_bp)->h_refcount));
+ mutex_unlock(&old_desc->lock);
+ }
+ }
+
+out:
+ return error;
+}
+
+/*
+ * pram_xattr_delete_inode()
+ *
+ * Free extended attribute resources associated with this inode. This
+ * is called immediately before an inode is freed.
+ */
+void pram_xattr_delete_inode(struct inode *inode)
+{
+ char *bp = NULL;
+ struct mb_cache_entry *ce;
+ struct pram_inode *pi;
+ struct pram_xblock_desc *desc;
+ struct super_block *sb = inode->i_sb;
+ struct pram_sb_info *sbi = (struct pram_sb_info *)sb->s_fs_info;
+ unsigned long blocknr;
+
+ pi = pram_get_inode(sb, inode->i_ino);
+ if (!pi)
+ goto cleanup;
+ down_write(&PRAM_I(inode)->xattr_sem);
+ if (!pi->i_xattr)
+ goto cleanup;
+ bp = pram_get_block(sb, be64_to_cpu(pi->i_xattr));
+ if (!bp) {
+ pram_err(sb, "inode %ld: block %llu read error", inode->i_ino,
+ be64_to_cpu(pi->i_xattr));
+ goto cleanup;
+ }
+ blocknr = pram_get_blocknr(sb, be64_to_cpu(pi->i_xattr));
+ if (HDR(bp)->h_magic != cpu_to_be32(PRAM_XATTR_MAGIC)) {
+ pram_err(sb, "inode %ld: bad block %llu", inode->i_ino,
+ be64_to_cpu(pi->i_xattr));
+ goto cleanup;
+ }
+ ce = mb_cache_entry_get(pram_xattr_cache, (struct block_device *)sbi, blocknr);
+ desc = GET_DESC(sbi, blocknr);
+ if (IS_ERR(desc))
+ goto cleanup;
+ mutex_lock(&desc->lock);
+ if (HDR(bp)->h_refcount == cpu_to_be32(1)) {
+ if (ce)
+ mb_cache_entry_free(ce);
+ mark_free_desc(desc);
+ } else {
+ be32_add_cpu(&HDR(bp)->h_refcount, -1);
+ if (ce)
+ mb_cache_entry_release(ce);
+ ea_bdebug(blocknr, "refcount now=%d",
+ be32_to_cpu(HDR(bp)->h_refcount));
+ mutex_unlock(&desc->lock);
+ }
+ desc_put(sb, desc);
+
+cleanup:
+ up_write(&PRAM_I(inode)->xattr_sem);
+}
+
+/*
+ * pram_xattr_put_super()
+ *
+ * This is called when a file system is unmounted.
+ */
+void pram_xattr_put_super(struct super_block *sb)
+{
+ struct pram_sb_info *sbi = (struct pram_sb_info *)sb->s_fs_info;
+ /*
+ * NOTE: we haven't got any block device to use with mb. Mb code
+ * doesn't use the pointer but it uses only the address as unique
+ * key so it's safe to use a "general purpose" address. We use
+ * super block info data as unique key. Maybe it'd be better to
+ * change mb code in order to use a generic void pointer to a
+ * generic id.
+ */
+ mb_cache_shrink((struct block_device *)sbi);
+ erase_tree(sbi, pram_xblock_desc_cache);
+ kmem_cache_shrink(pram_xblock_desc_cache);
+}
+
+
+/*
+ * pram_xattr_cache_insert()
+ *
+ * Create a new entry in the extended attribute cache, and insert
+ * it unless such an entry is already in the cache.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+static int pram_xattr_cache_insert(struct super_block *sb, unsigned long blocknr, u32 xhash)
+{
+ struct pram_sb_info *sbi = (struct pram_sb_info *)sb->s_fs_info;
+ __u32 hash = be32_to_cpu(xhash);
+ struct mb_cache_entry *ce;
+ int error;
+
+ ce = mb_cache_entry_alloc(pram_xattr_cache, GFP_NOFS);
+ if (!ce)
+ return -ENOMEM;
+ error = mb_cache_entry_insert(ce, (struct block_device *)sbi, blocknr, hash);
+ if (error) {
+ mb_cache_entry_free(ce);
+ if (error == -EBUSY) {
+ ea_bdebug(blocknr, "already in cache");
+ error = 0;
+ }
+ } else {
+ ea_bdebug(blocknr, "inserting [%x]", (int)hash);
+ mb_cache_entry_release(ce);
+ }
+ return error;
+}
+
+/*
+ * pram_xattr_cmp()
+ *
+ * Compare two extended attribute blocks for equality.
+ *
+ * Returns 0 if the blocks are equal, 1 if they differ, and
+ * a negative error number on errors.
+ */
+static int pram_xattr_cmp(struct pram_xattr_header *header1,
+ struct pram_xattr_header *header2)
+{
+ struct pram_xattr_entry *entry1, *entry2;
+
+ entry1 = ENTRY(header1+1);
+ entry2 = ENTRY(header2+1);
+ while (!IS_LAST_ENTRY(entry1)) {
+ if (IS_LAST_ENTRY(entry2))
+ return 1;
+ if (entry1->e_hash != entry2->e_hash ||
+ entry1->e_name_index != entry2->e_name_index ||
+ entry1->e_name_len != entry2->e_name_len ||
+ entry1->e_value_size != entry2->e_value_size ||
+ memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
+ return 1;
+ if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
+ return -EIO;
+ if (memcmp((char *)header1 + be16_to_cpu(entry1->e_value_offs),
+ (char *)header2 + be16_to_cpu(entry2->e_value_offs),
+ be32_to_cpu(entry1->e_value_size)))
+ return 1;
+
+ entry1 = PRAM_XATTR_NEXT(entry1);
+ entry2 = PRAM_XATTR_NEXT(entry2);
+ }
+ if (!IS_LAST_ENTRY(entry2))
+ return 1;
+ return 0;
+}
+
+/*
+ * pram_xattr_cache_find()
+ *
+ * Find an identical extended attribute block.
+ *
+ * Returns a locked extended block descriptor for the block found, or
+ * NULL if such a block was not found or an error occurred.
+ * The block, however, is not memory unlocked.
+ */
+static struct pram_xblock_desc *pram_xattr_cache_find(struct inode *inode, struct pram_xattr_header *header)
+{
+ __u32 hash = be32_to_cpu(header->h_hash);
+ struct mb_cache_entry *ce;
+ struct pram_xblock_desc *desc;
+ struct super_block *sb = inode->i_sb;
+ struct pram_sb_info *sbi = (struct pram_sb_info *)sb->s_fs_info;
+
+ if (!header->h_hash)
+ return NULL; /* never share */
+ ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
+again:
+ ce = mb_cache_entry_find_first(pram_xattr_cache, (struct block_device *)sbi, hash);
+ while (ce) {
+ char *bp;
+
+ if (IS_ERR(ce)) {
+ if (PTR_ERR(ce) == -EAGAIN)
+ goto again;
+ break;
+ }
+
+ bp = pram_get_block(sb, pram_get_block_off(sb, (unsigned long)ce->e_block));
+ if (!bp) {
+ pram_err(sb, "inode %ld: block %ld read error",
+ inode->i_ino, (unsigned long) ce->e_block);
+ } else {
+ desc = LOOKUP_DESC(sbi, ce->e_block);
+ if (!desc) {
+ mb_cache_entry_release(ce);
+ return NULL;
+ }
+ mutex_lock(&desc->lock);
+ if (be32_to_cpu(HDR(bp)->h_refcount) >
+ PRAM_XATTR_REFCOUNT_MAX) {
+ ea_idebug(inode, "block %ld refcount %d>%d",
+ (unsigned long) ce->e_block,
+ be32_to_cpu(HDR(bp)->h_refcount),
+ PRAM_XATTR_REFCOUNT_MAX);
+ } else if (!pram_xattr_cmp(header, HDR(bp))) {
+ mb_cache_entry_release(ce);
+ return desc;
+ }
+ mutex_unlock(&desc->lock);
+ }
+ ce = mb_cache_entry_find_next(ce, (struct block_device *)sbi, hash);
+ }
+ return NULL;
+}
+
+#define NAME_HASH_SHIFT 5
+#define VALUE_HASH_SHIFT 16
+
+/*
+ * pram_xattr_hash_entry()
+ *
+ * Compute the hash of an extended attribute.
+ */
+static inline void pram_xattr_hash_entry(struct pram_xattr_header *header,
+ struct pram_xattr_entry *entry)
+{
+ __u32 hash = 0;
+ char *name = entry->e_name;
+ int n;
+
+ for (n = 0; n < entry->e_name_len; n++) {
+ hash = (hash << NAME_HASH_SHIFT) ^
+ (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
+ *name++;
+ }
+
+ if (entry->e_value_block == 0 && entry->e_value_size != 0) {
+ __be32 *value = (__be32 *)((char *)header +
+ be16_to_cpu(entry->e_value_offs));
+ for (n = (be32_to_cpu(entry->e_value_size) +
+ PRAM_XATTR_ROUND) >> PRAM_XATTR_PAD_BITS; n; n--) {
+ hash = (hash << VALUE_HASH_SHIFT) ^
+ (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
+ be32_to_cpu(*value++);
+ }
+ }
+ entry->e_hash = cpu_to_be32(hash);
+}
+
+#undef NAME_HASH_SHIFT
+#undef VALUE_HASH_SHIFT
+
+#define BLOCK_HASH_SHIFT 16
+
+/*
+ * pram_xattr_rehash()
+ *
+ * Re-compute the extended attribute hash value after an entry has changed.
+ */
+static void pram_xattr_rehash(struct pram_xattr_header *header,
+ struct pram_xattr_entry *entry)
+{
+ struct pram_xattr_entry *here;
+ __u32 hash = 0;
+
+ pram_xattr_hash_entry(header, entry);
+ here = ENTRY(header+1);
+ while (!IS_LAST_ENTRY(here)) {
+ if (!here->e_hash) {
+ /* Block is not shared if an entry's hash value == 0 */
+ hash = 0;
+ break;
+ }
+ hash = (hash << BLOCK_HASH_SHIFT) ^
+ (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
+ be32_to_cpu(here->e_hash);
+ here = PRAM_XATTR_NEXT(here);
+ }
+ header->h_hash = cpu_to_be32(hash);
+}
+
+#undef BLOCK_HASH_SHIFT
+
+static void init_xblock_desc_once(void *foo)
+{
+ struct pram_xblock_desc *desc = (struct pram_xblock_desc *) foo;
+
+ xblock_desc_init_once(desc);
+}
+
+int __init init_pram_xattr(void)
+{
+ int ret = 0;
+ pram_xattr_cache = mb_cache_create("pram_xattr", 6);
+ if (!pram_xattr_cache) {
+ ret = -ENOMEM;
+ goto fail1;
+ }
+
+ pram_xblock_desc_cache = kmem_cache_create("pram_xblock_desc",
+ sizeof(struct pram_xblock_desc),
+ 0, (SLAB_RECLAIM_ACCOUNT|
+ SLAB_MEM_SPREAD),
+ init_xblock_desc_once);
+ if (!pram_xblock_desc_cache) {
+ ret = -ENOMEM;
+ goto fail2;
+ }
+
+ return 0;
+fail2:
+ mb_cache_destroy(pram_xattr_cache);
+fail1:
+ return ret;
+}
+
+void exit_pram_xattr(void)
+{
+ mb_cache_destroy(pram_xattr_cache);
+ kmem_cache_destroy(pram_xblock_desc_cache);
+}
diff -Nurp linux-2.6.36-orig/fs/pramfs/xattr.h linux-2.6.36/fs/pramfs/xattr.h
--- linux-2.6.36-orig/fs/pramfs/xattr.h 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.36/fs/pramfs/xattr.h 2010-11-27 11:13:37.000000000 +0100
@@ -0,0 +1,131 @@
+/*
+ * BRIEF DESCRIPTION
+ *
+ * Extended attributes for the pram filesystem.
+ *
+ * Copyright 2010 Marco Stornelli <marco.stornelli@...il.com>
+ *
+ * based on fs/ext2/xattr.h with the following copyright:
+ *
+ *(C) 2001 Andreas Gruenbacher, <a.gruenbacher@...puter.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/init.h>
+#include <linux/xattr.h>
+
+/* Magic value in attribute blocks */
+#define PRAM_XATTR_MAGIC 0x6d617270
+
+/* Maximum number of references to one attribute block */
+#define PRAM_XATTR_REFCOUNT_MAX 1024
+
+/* Name indexes */
+#define PRAM_XATTR_INDEX_USER 1
+#define PRAM_XATTR_INDEX_POSIX_ACL_ACCESS 2
+#define PRAM_XATTR_INDEX_POSIX_ACL_DEFAULT 3
+#define PRAM_XATTR_INDEX_TRUSTED 4
+#define PRAM_XATTR_INDEX_SECURITY 5
+
+struct pram_xattr_header {
+ __be32 h_magic; /* magic number for identification */
+ __be32 h_refcount; /* reference count */
+ __be32 h_hash; /* hash value of all attributes */
+ __u32 h_reserved[4]; /* zero right now */
+};
+
+struct pram_xattr_entry {
+ __u8 e_name_len; /* length of name */
+ __u8 e_name_index; /* attribute name index */
+ __be16 e_value_offs; /* offset in disk block of value */
+ __be32 e_value_block; /* disk block attribute is stored on (n/i) */
+ __be32 e_value_size; /* size of attribute value */
+ __be32 e_hash; /* hash value of name and value */
+ char e_name[0]; /* attribute name */
+};
+
+#define PRAM_XATTR_PAD_BITS 2
+#define PRAM_XATTR_PAD (1<<PRAM_XATTR_PAD_BITS)
+#define PRAM_XATTR_ROUND (PRAM_XATTR_PAD-1)
+#define PRAM_XATTR_LEN(name_len) \
+ (((name_len) + PRAM_XATTR_ROUND + \
+ sizeof(struct pram_xattr_entry)) & ~PRAM_XATTR_ROUND)
+#define PRAM_XATTR_NEXT(entry) \
+ ((struct pram_xattr_entry *)( \
+ (char *)(entry) + PRAM_XATTR_LEN((entry)->e_name_len)))
+#define PRAM_XATTR_SIZE(size) \
+ (((size) + PRAM_XATTR_ROUND) & ~PRAM_XATTR_ROUND)
+
+#ifdef CONFIG_PRAMFS_XATTR
+
+extern const struct xattr_handler pram_xattr_user_handler;
+extern const struct xattr_handler pram_xattr_trusted_handler;
+extern const struct xattr_handler pram_xattr_acl_access_handler;
+extern const struct xattr_handler pram_xattr_acl_default_handler;
+extern const struct xattr_handler pram_xattr_security_handler;
+
+extern ssize_t pram_listxattr(struct dentry *, char *, size_t);
+
+extern int pram_xattr_get(struct inode *, int, const char *, void *, size_t);
+extern int pram_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
+
+extern void pram_xattr_delete_inode(struct inode *);
+extern void pram_xattr_put_super(struct super_block *);
+
+extern int init_pram_xattr(void) __init;
+extern void exit_pram_xattr(void);
+
+extern const struct xattr_handler *pram_xattr_handlers[];
+
+# else /* CONFIG_PRAMFS_XATTR */
+
+static inline int
+pram_xattr_get(struct inode *inode, int name_index,
+ const char *name, void *buffer, size_t size)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int
+pram_xattr_set(struct inode *inode, int name_index, const char *name,
+ const void *value, size_t size, int flags)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline void
+pram_xattr_delete_inode(struct inode *inode)
+{
+}
+
+static inline void
+pram_xattr_put_super(struct super_block *sb)
+{
+}
+
+static inline int
+init_pram_xattr(void)
+{
+ return 0;
+}
+
+static inline void
+exit_pram_xattr(void)
+{
+}
+
+#define pram_xattr_handlers NULL
+
+# endif /* CONFIG_PRAMFS_XATTR */
+
+#ifdef CONFIG_PRAMFS_SECURITY
+extern int pram_init_security(struct inode *inode, struct inode *dir);
+#else
+static inline int pram_init_security(struct inode *inode, struct inode *dir)
+{
+ return 0;
+}
+#endif
diff -Nurp linux-2.6.36-orig/fs/pramfs/xattr_security.c linux-2.6.36/fs/pramfs/xattr_security.c
--- linux-2.6.36-orig/fs/pramfs/xattr_security.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.36/fs/pramfs/xattr_security.c 2010-11-27 11:13:46.000000000 +0100
@@ -0,0 +1,78 @@
+/*
+ * BRIEF DESCRIPTION
+ *
+ * Handler for storing security labels as extended attributes.
+ *
+ * Copyright 2010 Marco Stornelli <marco.stornelli@...il.com>
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/pram_fs.h>
+#include <linux/security.h>
+#include "xattr.h"
+
+static size_t pram_xattr_security_list(struct dentry *dentry, char *list,
+ size_t list_size, const char *name,
+ size_t name_len, int type)
+{
+ const int prefix_len = XATTR_SECURITY_PREFIX_LEN;
+ const size_t total_len = prefix_len + name_len + 1;
+
+ if (list && total_len <= list_size) {
+ memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
+ memcpy(list+prefix_len, name, name_len);
+ list[prefix_len + name_len] = '\0';
+ }
+ return total_len;
+}
+
+static int pram_xattr_security_get(struct dentry *dentry, const char *name,
+ void *buffer, size_t size, int type)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ return pram_xattr_get(dentry->d_inode, PRAM_XATTR_INDEX_SECURITY, name,
+ buffer, size);
+}
+
+static int pram_xattr_security_set(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags, int type)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ return pram_xattr_set(dentry->d_inode, PRAM_XATTR_INDEX_SECURITY, name,
+ value, size, flags);
+}
+
+int pram_init_security(struct inode *inode, struct inode *dir)
+{
+ int err;
+ size_t len;
+ void *value;
+ char *name;
+
+ err = security_inode_init_security(inode, dir, &name, &value, &len);
+ if (err) {
+ if (err == -EOPNOTSUPP)
+ return 0;
+ return err;
+ }
+ err = pram_xattr_set(inode, PRAM_XATTR_INDEX_SECURITY,
+ name, value, len, 0);
+ kfree(name);
+ kfree(value);
+ return err;
+}
+
+const struct xattr_handler pram_xattr_security_handler = {
+ .prefix = XATTR_SECURITY_PREFIX,
+ .list = pram_xattr_security_list,
+ .get = pram_xattr_security_get,
+ .set = pram_xattr_security_set,
+};
diff -Nurp linux-2.6.36-orig/fs/pramfs/xattr_trusted.c linux-2.6.36/fs/pramfs/xattr_trusted.c
--- linux-2.6.36-orig/fs/pramfs/xattr_trusted.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.36/fs/pramfs/xattr_trusted.c 2010-11-27 11:13:51.000000000 +0100
@@ -0,0 +1,65 @@
+/*
+ * BRIEF DESCRIPTION
+ *
+ * Handler for trusted extended attributes.
+ *
+ * Copyright 2010 Marco Stornelli <marco.stornelli@...il.com>
+ *
+ * based on fs/ext2/xattr_trusted.c with the following copyright:
+ *
+ * Copyright (C) 2003 by Andreas Gruenbacher, <a.gruenbacher@...puter.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include <linux/pram_fs.h>
+#include "xattr.h"
+
+static size_t pram_xattr_trusted_list(struct dentry *dentry, char *list,
+ size_t list_size, const char *name,
+ size_t name_len, int type)
+{
+ const int prefix_len = XATTR_TRUSTED_PREFIX_LEN;
+ const size_t total_len = prefix_len + name_len + 1;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return 0;
+
+ if (list && total_len <= list_size) {
+ memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
+ memcpy(list+prefix_len, name, name_len);
+ list[prefix_len + name_len] = '\0';
+ }
+ return total_len;
+}
+
+static int pram_xattr_trusted_get(struct dentry *dentry, const char *name,
+ void *buffer, size_t size, int type)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ return pram_xattr_get(dentry->d_inode, PRAM_XATTR_INDEX_TRUSTED, name,
+ buffer, size);
+}
+
+static int pram_xattr_trusted_set(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags, int type)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ return pram_xattr_set(dentry->d_inode, PRAM_XATTR_INDEX_TRUSTED, name,
+ value, size, flags);
+}
+
+const struct xattr_handler pram_xattr_trusted_handler = {
+ .prefix = XATTR_TRUSTED_PREFIX,
+ .list = pram_xattr_trusted_list,
+ .get = pram_xattr_trusted_get,
+ .set = pram_xattr_trusted_set,
+};
diff -Nurp linux-2.6.36-orig/fs/pramfs/xattr_user.c linux-2.6.36/fs/pramfs/xattr_user.c
--- linux-2.6.36-orig/fs/pramfs/xattr_user.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.36/fs/pramfs/xattr_user.c 2010-11-27 14:31:00.000000000 +0100
@@ -0,0 +1,68 @@
+/*
+ * BRIEF DESCRIPTION
+ *
+ * Handler for extended user attributes.
+ *
+ * Copyright 2010 Marco Stornelli <marco.stornelli@...il.com>
+ *
+ * based on fs/ext2/xattr_user.c with the following copyright:
+ *
+ * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@...puter.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include "pram.h"
+#include "xattr.h"
+
+static size_t pram_xattr_user_list(struct dentry *dentry, char *list, size_t list_size,
+ const char *name, size_t name_len, int type)
+{
+ const size_t prefix_len = XATTR_USER_PREFIX_LEN;
+ const size_t total_len = prefix_len + name_len + 1;
+
+ if (!test_opt(dentry->d_sb, XATTR_USER))
+ return 0;
+
+ if (list && total_len <= list_size) {
+ memcpy(list, XATTR_USER_PREFIX, prefix_len);
+ memcpy(list+prefix_len, name, name_len);
+ list[prefix_len + name_len] = '\0';
+ }
+ return total_len;
+}
+
+static int pram_xattr_user_get(struct dentry *dentry, const char *name,
+ void *buffer, size_t size, int type)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ if (!test_opt(dentry->d_sb, XATTR_USER))
+ return -EOPNOTSUPP;
+ return pram_xattr_get(dentry->d_inode, PRAM_XATTR_INDEX_USER,
+ name, buffer, size);
+}
+
+static int pram_xattr_user_set(struct dentry *dentry, const char *name,
+ const void *value, size_t size, int flags, int type)
+{
+ if (strcmp(name, "") == 0)
+ return -EINVAL;
+ if (!test_opt(dentry->d_sb, XATTR_USER))
+ return -EOPNOTSUPP;
+
+ return pram_xattr_set(dentry->d_inode, PRAM_XATTR_INDEX_USER,
+ name, value, size, flags);
+}
+
+const struct xattr_handler pram_xattr_user_handler = {
+ .prefix = XATTR_USER_PREFIX,
+ .list = pram_xattr_user_list,
+ .get = pram_xattr_user_get,
+ .set = pram_xattr_user_set,
+};
--
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