root/fs/hfsplus/xattr.c
// SPDX-License-Identifier: GPL-2.0
/*
 * linux/fs/hfsplus/xattr.c
 *
 * Vyacheslav Dubeyko <slava@dubeyko.com>
 *
 * Logic of processing extended attributes
 */

#include "hfsplus_fs.h"
#include <linux/nls.h>
#include "xattr.h"

static int hfsplus_removexattr(struct inode *inode, const char *name);

const struct xattr_handler * const hfsplus_xattr_handlers[] = {
        &hfsplus_xattr_osx_handler,
        &hfsplus_xattr_user_handler,
        &hfsplus_xattr_trusted_handler,
        &hfsplus_xattr_security_handler,
        NULL
};

static int strcmp_xattr_finder_info(const char *name)
{
        if (name) {
                return strncmp(name, HFSPLUS_XATTR_FINDER_INFO_NAME,
                                sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME));
        }
        return -1;
}

static int strcmp_xattr_acl(const char *name)
{
        if (name) {
                return strncmp(name, HFSPLUS_XATTR_ACL_NAME,
                                sizeof(HFSPLUS_XATTR_ACL_NAME));
        }
        return -1;
}

static bool is_known_namespace(const char *name)
{
        if (strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) &&
            strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) &&
            strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
            strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
                return false;

        return true;
}

static void hfsplus_init_header_node(struct inode *attr_file,
                                        u32 clump_size,
                                        char *buf, u16 node_size)
{
        struct hfs_bnode_desc *desc;
        struct hfs_btree_header_rec *head;
        u16 offset;
        __be16 *rec_offsets;
        u32 hdr_node_map_rec_bits;
        char *bmp;
        u32 used_nodes;
        u32 used_bmp_bytes;
        u64 tmp;

        hfs_dbg("clump %u, node_size %u\n",
                clump_size, node_size);

        /* The end of the node contains list of record offsets */
        rec_offsets = (__be16 *)(buf + node_size);

        desc = (struct hfs_bnode_desc *)buf;
        desc->type = HFS_NODE_HEADER;
        desc->num_recs = cpu_to_be16(HFSPLUS_BTREE_HDR_NODE_RECS_COUNT);
        offset = sizeof(struct hfs_bnode_desc);
        *--rec_offsets = cpu_to_be16(offset);

        head = (struct hfs_btree_header_rec *)(buf + offset);
        head->node_size = cpu_to_be16(node_size);
        tmp = i_size_read(attr_file);
        do_div(tmp, node_size);
        head->node_count = cpu_to_be32(tmp);
        head->free_nodes = cpu_to_be32(be32_to_cpu(head->node_count) - 1);
        head->clump_size = cpu_to_be32(clump_size);
        head->attributes |= cpu_to_be32(HFS_TREE_BIGKEYS | HFS_TREE_VARIDXKEYS);
        head->max_key_len = cpu_to_be16(HFSPLUS_ATTR_KEYLEN - sizeof(u16));
        offset += sizeof(struct hfs_btree_header_rec);
        *--rec_offsets = cpu_to_be16(offset);
        offset += HFSPLUS_BTREE_HDR_USER_BYTES;
        *--rec_offsets = cpu_to_be16(offset);

        hdr_node_map_rec_bits = 8 * (node_size - offset - (4 * sizeof(u16)));
        if (be32_to_cpu(head->node_count) > hdr_node_map_rec_bits) {
                u32 map_node_bits;
                u32 map_nodes;

                desc->next = cpu_to_be32(be32_to_cpu(head->leaf_tail) + 1);
                map_node_bits = 8 * (node_size - sizeof(struct hfs_bnode_desc) -
                                        (2 * sizeof(u16)) - 2);
                map_nodes = (be32_to_cpu(head->node_count) -
                                hdr_node_map_rec_bits +
                                (map_node_bits - 1)) / map_node_bits;
                be32_add_cpu(&head->free_nodes, 0 - map_nodes);
        }

        bmp = buf + offset;
        used_nodes =
                be32_to_cpu(head->node_count) - be32_to_cpu(head->free_nodes);
        used_bmp_bytes = used_nodes / 8;
        if (used_bmp_bytes) {
                memset(bmp, 0xFF, used_bmp_bytes);
                bmp += used_bmp_bytes;
                used_nodes %= 8;
        }
        *bmp = ~(0xFF >> used_nodes);
        offset += hdr_node_map_rec_bits / 8;
        *--rec_offsets = cpu_to_be16(offset);
}

static int hfsplus_create_attributes_file(struct super_block *sb)
{
        int err = 0;
        struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
        struct inode *attr_file;
        struct hfsplus_inode_info *hip;
        u32 clump_size;
        u16 node_size = HFSPLUS_ATTR_TREE_NODE_SIZE;
        char *buf;
        int index, written;
        struct address_space *mapping;
        struct page *page;
        int old_state = HFSPLUS_EMPTY_ATTR_TREE;

        hfs_dbg("ino %d\n", HFSPLUS_ATTR_CNID);

check_attr_tree_state_again:
        switch (atomic_read(&sbi->attr_tree_state)) {
        case HFSPLUS_EMPTY_ATTR_TREE:
                if (old_state != atomic_cmpxchg(&sbi->attr_tree_state,
                                                old_state,
                                                HFSPLUS_CREATING_ATTR_TREE))
                        goto check_attr_tree_state_again;
                break;
        case HFSPLUS_CREATING_ATTR_TREE:
                /*
                 * This state means that another thread is in process
                 * of AttributesFile creation. Theoretically, it is
                 * possible to be here. But really __setxattr() method
                 * first of all calls hfs_find_init() for lookup in
                 * B-tree of CatalogFile. This method locks mutex of
                 * CatalogFile's B-tree. As a result, if some thread
                 * is inside AttributedFile creation operation then
                 * another threads will be waiting unlocking of
                 * CatalogFile's B-tree's mutex. However, if code will
                 * change then we will return error code (-EAGAIN) from
                 * here. Really, it means that first try to set of xattr
                 * fails with error but second attempt will have success.
                 */
                return -EAGAIN;
        case HFSPLUS_VALID_ATTR_TREE:
                return 0;
        case HFSPLUS_FAILED_ATTR_TREE:
                return -EOPNOTSUPP;
        default:
                BUG();
        }

        attr_file = hfsplus_iget(sb, HFSPLUS_ATTR_CNID);
        if (IS_ERR(attr_file)) {
                pr_err("failed to load attributes file\n");
                return PTR_ERR(attr_file);
        }

        if (i_size_read(attr_file) != 0) {
                err = -EIO;
                pr_err("detected inconsistent attributes file, running fsck.hfsplus is recommended.\n");
                goto end_attr_file_creation;
        }

        hip = HFSPLUS_I(attr_file);

        clump_size = hfsplus_calc_btree_clump_size(sb->s_blocksize,
                                                    node_size,
                                                    sbi->sect_count,
                                                    HFSPLUS_ATTR_CNID);

        mutex_lock(&hip->extents_lock);
        hip->clump_blocks = clump_size >> sbi->alloc_blksz_shift;
        mutex_unlock(&hip->extents_lock);

        if (sbi->free_blocks <= (hip->clump_blocks << 1)) {
                err = -ENOSPC;
                goto end_attr_file_creation;
        }

        while (hip->alloc_blocks < hip->clump_blocks) {
                err = hfsplus_file_extend(attr_file, false);
                if (unlikely(err)) {
                        pr_err("failed to extend attributes file\n");
                        goto end_attr_file_creation;
                }
                hip->phys_size = attr_file->i_size =
                        (loff_t)hip->alloc_blocks << sbi->alloc_blksz_shift;
                hip->fs_blocks = hip->alloc_blocks << sbi->fs_shift;
                inode_set_bytes(attr_file, attr_file->i_size);
        }

        buf = kzalloc(node_size, GFP_NOFS);
        if (!buf) {
                err = -ENOMEM;
                goto end_attr_file_creation;
        }

        hfsplus_init_header_node(attr_file, clump_size, buf, node_size);

        mapping = attr_file->i_mapping;

        index = 0;
        written = 0;
        for (; written < node_size; index++, written += PAGE_SIZE) {
                void *kaddr;

                page = read_mapping_page(mapping, index, NULL);
                if (IS_ERR(page)) {
                        err = PTR_ERR(page);
                        goto failed_header_node_init;
                }

                kaddr = kmap_atomic(page);
                memcpy(kaddr, buf + written,
                        min_t(size_t, PAGE_SIZE, node_size - written));
                kunmap_atomic(kaddr);

                set_page_dirty(page);
                put_page(page);
        }

        hfsplus_mark_inode_dirty(attr_file, HFSPLUS_I_ATTR_DIRTY);

        sbi->attr_tree = hfs_btree_open(sb, HFSPLUS_ATTR_CNID);
        if (!sbi->attr_tree)
                pr_err("failed to load attributes file\n");

failed_header_node_init:
        kfree(buf);

end_attr_file_creation:
        iput(attr_file);

        if (!err)
                atomic_set(&sbi->attr_tree_state, HFSPLUS_VALID_ATTR_TREE);
        else if (err == -ENOSPC)
                atomic_set(&sbi->attr_tree_state, HFSPLUS_EMPTY_ATTR_TREE);
        else
                atomic_set(&sbi->attr_tree_state, HFSPLUS_FAILED_ATTR_TREE);

        return err;
}

static inline
bool is_xattr_operation_supported(struct inode *inode)
{
        if (HFSPLUS_IS_RSRC(inode))
                return false;

        return true;
}

int __hfsplus_setxattr(struct inode *inode, const char *name,
                        const void *value, size_t size, int flags)
{
        int err;
        struct hfs_find_data cat_fd;
        hfsplus_cat_entry entry;
        u16 cat_entry_flags, cat_entry_type;
        u16 folder_finderinfo_len = sizeof(DInfo) + sizeof(DXInfo);
        u16 file_finderinfo_len = sizeof(FInfo) + sizeof(FXInfo);

        hfs_dbg("ino %lu, name %s, value %p, size %zu\n",
                inode->i_ino, name ? name : NULL,
                value, size);

        if (!is_xattr_operation_supported(inode))
                return -EOPNOTSUPP;

        if (value == NULL)
                return hfsplus_removexattr(inode, name);

        err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
        if (err) {
                pr_err("can't init xattr find struct\n");
                return err;
        }

        err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
        if (err) {
                pr_err("catalog searching failed\n");
                goto end_setxattr;
        }

        if (!strcmp_xattr_finder_info(name)) {
                if (flags & XATTR_CREATE) {
                        pr_err("xattr exists yet\n");
                        err = -EOPNOTSUPP;
                        goto end_setxattr;
                }
                hfs_bnode_read(cat_fd.bnode, &entry, cat_fd.entryoffset,
                                        sizeof(hfsplus_cat_entry));
                if (be16_to_cpu(entry.type) == HFSPLUS_FOLDER) {
                        if (size == folder_finderinfo_len) {
                                memcpy(&entry.folder.info, value,
                                                folder_finderinfo_len);
                                hfs_bnode_write(cat_fd.bnode, &entry,
                                        cat_fd.entryoffset,
                                        sizeof(struct hfsplus_cat_folder));
                                hfsplus_mark_inode_dirty(inode,
                                                HFSPLUS_I_CAT_DIRTY);
                        } else {
                                err = -ERANGE;
                                goto end_setxattr;
                        }
                } else if (be16_to_cpu(entry.type) == HFSPLUS_FILE) {
                        if (size == file_finderinfo_len) {
                                memcpy(&entry.file.info, value,
                                                file_finderinfo_len);
                                hfs_bnode_write(cat_fd.bnode, &entry,
                                        cat_fd.entryoffset,
                                        sizeof(struct hfsplus_cat_file));
                                hfsplus_mark_inode_dirty(inode,
                                                HFSPLUS_I_CAT_DIRTY);
                        } else {
                                err = -ERANGE;
                                goto end_setxattr;
                        }
                } else {
                        err = -EOPNOTSUPP;
                        goto end_setxattr;
                }
                goto end_setxattr;
        }

        if (!HFSPLUS_SB(inode->i_sb)->attr_tree) {
                err = hfsplus_create_attributes_file(inode->i_sb);
                if (unlikely(err))
                        goto end_setxattr;
        }

        if (hfsplus_attr_exists(inode, name)) {
                if (flags & XATTR_CREATE) {
                        pr_err("xattr exists yet\n");
                        err = -EOPNOTSUPP;
                        goto end_setxattr;
                }
                err = hfsplus_replace_attr(inode, name, value, size);
                if (err) {
                        hfs_dbg("unable to replace xattr: err %d\n", err);
                        goto end_setxattr;
                }
        } else {
                if (flags & XATTR_REPLACE) {
                        pr_err("cannot replace xattr\n");
                        err = -EOPNOTSUPP;
                        goto end_setxattr;
                }
                err = hfsplus_create_attr(inode, name, value, size);
                if (err) {
                        hfs_dbg("unable to store value: err %d\n", err);
                        goto end_setxattr;
                }
        }

        cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);
        if (cat_entry_type == HFSPLUS_FOLDER) {
                cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
                                    cat_fd.entryoffset +
                                    offsetof(struct hfsplus_cat_folder, flags));
                cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
                if (!strcmp_xattr_acl(name))
                        cat_entry_flags |= HFSPLUS_ACL_EXISTS;
                hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
                                offsetof(struct hfsplus_cat_folder, flags),
                                cat_entry_flags);
                hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
        } else if (cat_entry_type == HFSPLUS_FILE) {
                cat_entry_flags = hfs_bnode_read_u16(cat_fd.bnode,
                                    cat_fd.entryoffset +
                                    offsetof(struct hfsplus_cat_file, flags));
                cat_entry_flags |= HFSPLUS_XATTR_EXISTS;
                if (!strcmp_xattr_acl(name))
                        cat_entry_flags |= HFSPLUS_ACL_EXISTS;
                hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
                                    offsetof(struct hfsplus_cat_file, flags),
                                    cat_entry_flags);
                hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
        } else {
                pr_err("invalid catalog entry type\n");
                err = -EIO;
                goto end_setxattr;
        }

end_setxattr:
        hfs_find_exit(&cat_fd);
        hfs_dbg("finished: res %d\n", err);
        return err;
}

static size_t name_len(const char *xattr_name, size_t xattr_name_len)
{
        size_t len = xattr_name_len + 1;

        if (!is_known_namespace(xattr_name))
                len += XATTR_MAC_OSX_PREFIX_LEN;

        return len;
}

static ssize_t copy_name(char *buffer, const char *xattr_name, size_t name_len)
{
        ssize_t len;

        memset(buffer, 0, name_len);

        if (!is_known_namespace(xattr_name)) {
                len = scnprintf(buffer, name_len + XATTR_MAC_OSX_PREFIX_LEN,
                                 "%s%s", XATTR_MAC_OSX_PREFIX, xattr_name);
        } else {
                len = strscpy(buffer, xattr_name, name_len + 1);
                if (len < 0) {
                        pr_err("fail to copy name: err %zd\n", len);
                        len = 0;
                }
        }

        /* include NUL-byte in length for non-empty name */
        if (len >= 0)
                len++;
        return len;
}

int hfsplus_setxattr(struct inode *inode, const char *name,
                     const void *value, size_t size, int flags,
                     const char *prefix, size_t prefixlen)
{
        char *xattr_name;
        size_t xattr_name_len =
                NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1;
        int res;

        hfs_dbg("ino %lu, name %s, prefix %s, prefixlen %zu, "
                "value %p, size %zu\n",
                inode->i_ino, name ? name : NULL,
                prefix ? prefix : NULL, prefixlen,
                value, size);

        xattr_name = kmalloc(xattr_name_len, GFP_KERNEL);
        if (!xattr_name)
                return -ENOMEM;
        strcpy(xattr_name, prefix);
        strcpy(xattr_name + prefixlen, name);
        res = __hfsplus_setxattr(inode, xattr_name, value, size, flags);
        kfree(xattr_name);

        hfs_dbg("finished: res %d\n", res);

        return res;
}

static ssize_t hfsplus_getxattr_finder_info(struct inode *inode,
                                                void *value, size_t size)
{
        ssize_t res = 0;
        struct hfs_find_data fd;
        u16 entry_type;
        u16 folder_rec_len = sizeof(DInfo) + sizeof(DXInfo);
        u16 file_rec_len = sizeof(FInfo) + sizeof(FXInfo);
        u16 record_len = max(folder_rec_len, file_rec_len);
        u8 folder_finder_info[sizeof(DInfo) + sizeof(DXInfo)];
        u8 file_finder_info[sizeof(FInfo) + sizeof(FXInfo)];

        if (size >= record_len) {
                res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
                if (res) {
                        pr_err("can't init xattr find struct\n");
                        return res;
                }
                res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
                if (res)
                        goto end_getxattr_finder_info;
                entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);

                if (entry_type == HFSPLUS_FOLDER) {
                        hfs_bnode_read(fd.bnode, folder_finder_info,
                                fd.entryoffset +
                                offsetof(struct hfsplus_cat_folder, user_info),
                                folder_rec_len);
                        memcpy(value, folder_finder_info, folder_rec_len);
                        res = folder_rec_len;
                } else if (entry_type == HFSPLUS_FILE) {
                        hfs_bnode_read(fd.bnode, file_finder_info,
                                fd.entryoffset +
                                offsetof(struct hfsplus_cat_file, user_info),
                                file_rec_len);
                        memcpy(value, file_finder_info, file_rec_len);
                        res = file_rec_len;
                } else {
                        res = -EOPNOTSUPP;
                        goto end_getxattr_finder_info;
                }
        } else
                res = size ? -ERANGE : record_len;

end_getxattr_finder_info:
        if (size >= record_len)
                hfs_find_exit(&fd);
        return res;
}

ssize_t __hfsplus_getxattr(struct inode *inode, const char *name,
                         void *value, size_t size)
{
        struct hfs_find_data fd;
        hfsplus_attr_entry *entry;
        __be32 xattr_record_type;
        u32 record_type;
        u16 record_length = 0;
        ssize_t res;

        if (!is_xattr_operation_supported(inode))
                return -EOPNOTSUPP;

        if (!strcmp_xattr_finder_info(name))
                return hfsplus_getxattr_finder_info(inode, value, size);

        if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
                return -EOPNOTSUPP;

        entry = hfsplus_alloc_attr_entry();
        if (!entry) {
                pr_err("can't allocate xattr entry\n");
                return -ENOMEM;
        }

        res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
        if (res) {
                pr_err("can't init xattr find struct\n");
                goto failed_getxattr_init;
        }

        res = hfsplus_find_attr(inode->i_sb, inode->i_ino, name, &fd);
        if (res) {
                if (res == -ENOENT)
                        res = -ENODATA;
                else
                        pr_err("xattr searching failed\n");
                goto out;
        }

        hfs_bnode_read(fd.bnode, &xattr_record_type,
                        fd.entryoffset, sizeof(xattr_record_type));
        record_type = be32_to_cpu(xattr_record_type);
        if (record_type == HFSPLUS_ATTR_INLINE_DATA) {
                record_length = hfs_bnode_read_u16(fd.bnode,
                                fd.entryoffset +
                                offsetof(struct hfsplus_attr_inline_data,
                                length));
                if (record_length > HFSPLUS_MAX_INLINE_DATA_SIZE) {
                        pr_err("invalid xattr record size\n");
                        res = -EIO;
                        goto out;
                }
        } else if (record_type == HFSPLUS_ATTR_FORK_DATA ||
                        record_type == HFSPLUS_ATTR_EXTENTS) {
                pr_err("only inline data xattr are supported\n");
                res = -EOPNOTSUPP;
                goto out;
        } else {
                pr_err("invalid xattr record\n");
                res = -EIO;
                goto out;
        }

        if (size) {
                hfs_bnode_read(fd.bnode, entry, fd.entryoffset,
                                offsetof(struct hfsplus_attr_inline_data,
                                        raw_bytes) + record_length);
        }

        if (size >= record_length) {
                memcpy(value, entry->inline_data.raw_bytes, record_length);
                res = record_length;
        } else
                res = size ? -ERANGE : record_length;

out:
        hfs_find_exit(&fd);

failed_getxattr_init:
        hfsplus_destroy_attr_entry(entry);
        return res;
}

ssize_t hfsplus_getxattr(struct inode *inode, const char *name,
                         void *value, size_t size,
                         const char *prefix, size_t prefixlen)
{
        int res;
        char *xattr_name;

        hfs_dbg("ino %lu, name %s, prefix %s\n",
                inode->i_ino, name ? name : NULL,
                prefix ? prefix : NULL);

        xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
                             GFP_KERNEL);
        if (!xattr_name)
                return -ENOMEM;

        strcpy(xattr_name, prefix);
        strcpy(xattr_name + prefixlen, name);

        res = __hfsplus_getxattr(inode, xattr_name, value, size);
        kfree(xattr_name);

        hfs_dbg("finished: res %d\n", res);

        return res;

}

static inline int can_list(const char *xattr_name)
{
        if (!xattr_name)
                return 0;

        return strncmp(xattr_name, XATTR_TRUSTED_PREFIX,
                        XATTR_TRUSTED_PREFIX_LEN) ||
                                capable(CAP_SYS_ADMIN);
}

static ssize_t hfsplus_listxattr_finder_info(struct dentry *dentry,
                                                char *buffer, size_t size)
{
        ssize_t res;
        struct inode *inode = d_inode(dentry);
        struct hfs_find_data fd;
        u16 entry_type;
        u8 folder_finder_info[sizeof(DInfo) + sizeof(DXInfo)];
        u8 file_finder_info[sizeof(FInfo) + sizeof(FXInfo)];
        unsigned long len, found_bit;
        int xattr_name_len, symbols_count;

        res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
        if (res) {
                pr_err("can't init xattr find struct\n");
                return res;
        }

        res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
        if (res)
                goto end_listxattr_finder_info;

        entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
        if (entry_type == HFSPLUS_FOLDER) {
                len = sizeof(DInfo) + sizeof(DXInfo);
                hfs_bnode_read(fd.bnode, folder_finder_info,
                                fd.entryoffset +
                                offsetof(struct hfsplus_cat_folder, user_info),
                                len);
                found_bit = find_first_bit((void *)folder_finder_info, len*8);
        } else if (entry_type == HFSPLUS_FILE) {
                len = sizeof(FInfo) + sizeof(FXInfo);
                hfs_bnode_read(fd.bnode, file_finder_info,
                                fd.entryoffset +
                                offsetof(struct hfsplus_cat_file, user_info),
                                len);
                found_bit = find_first_bit((void *)file_finder_info, len*8);
        } else {
                res = -EOPNOTSUPP;
                goto end_listxattr_finder_info;
        }

        if (found_bit >= (len*8))
                res = 0;
        else {
                symbols_count = sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME) - 1;
                xattr_name_len =
                        name_len(HFSPLUS_XATTR_FINDER_INFO_NAME, symbols_count);
                if (!buffer || !size) {
                        if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME))
                                res = xattr_name_len;
                } else if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME)) {
                        if (size < xattr_name_len)
                                res = -ERANGE;
                        else {
                                res = copy_name(buffer,
                                                HFSPLUS_XATTR_FINDER_INFO_NAME,
                                                symbols_count);
                        }
                }
        }

end_listxattr_finder_info:
        hfs_find_exit(&fd);

        return res;
}

ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
        ssize_t err;
        ssize_t res;
        struct inode *inode = d_inode(dentry);
        struct hfs_find_data fd;
        struct hfsplus_attr_key attr_key;
        char *strbuf;
        size_t strbuf_size;
        int xattr_name_len;

        hfs_dbg("ino %lu\n", inode->i_ino);

        if (!is_xattr_operation_supported(inode))
                return -EOPNOTSUPP;

        res = hfsplus_listxattr_finder_info(dentry, buffer, size);
        if (res < 0)
                return res;
        else if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
                return (res == 0) ? -EOPNOTSUPP : res;

        err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->attr_tree, &fd);
        if (err) {
                pr_err("can't init xattr find struct\n");
                return err;
        }

        strbuf_size = NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN +
                        XATTR_MAC_OSX_PREFIX_LEN + 1;
        strbuf = kzalloc(strbuf_size, GFP_KERNEL);
        if (!strbuf) {
                res = -ENOMEM;
                goto out;
        }

        err = hfsplus_find_attr(inode->i_sb, inode->i_ino, NULL, &fd);
        if (err) {
                if (err == -ENOENT) {
                        res = 0;
                        goto end_listxattr;
                } else {
                        res = err;
                        goto end_listxattr;
                }
        }

        for (;;) {
                u16 key_len = hfs_bnode_read_u16(fd.bnode, fd.keyoffset);

                if (key_len == 0 || key_len > fd.tree->max_key_len) {
                        pr_err("invalid xattr key length: %d\n", key_len);
                        res = -EIO;
                        goto end_listxattr;
                }

                hfs_bnode_read(fd.bnode, &attr_key,
                                fd.keyoffset, key_len + sizeof(key_len));

                if (be32_to_cpu(attr_key.cnid) != inode->i_ino)
                        goto end_listxattr;

                xattr_name_len = NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN;
                if (hfsplus_uni2asc_xattr_str(inode->i_sb,
                                              &fd.key->attr.key_name, strbuf,
                                              &xattr_name_len)) {
                        pr_err("unicode conversion failed\n");
                        res = -EIO;
                        goto end_listxattr;
                }

                if (!buffer || !size) {
                        if (can_list(strbuf))
                                res += name_len(strbuf, xattr_name_len);
                } else if (can_list(strbuf)) {
                        if (size < (res + name_len(strbuf, xattr_name_len))) {
                                pr_err("size %zu, res %zd, name_len %zu\n",
                                        size, res,
                                        name_len(strbuf, xattr_name_len));
                                res = -ERANGE;
                                goto end_listxattr;
                        } else
                                res += copy_name(buffer + res,
                                                strbuf, xattr_name_len);
                }

                memset(fd.key->attr.key_name.unicode, 0,
                        sizeof(fd.key->attr.key_name.unicode));
                memset(strbuf, 0, strbuf_size);

                if (hfs_brec_goto(&fd, 1))
                        goto end_listxattr;
        }

end_listxattr:
        kfree(strbuf);
out:
        hfs_find_exit(&fd);

        hfs_dbg("finished: res %zd\n", res);

        return res;
}

static int hfsplus_removexattr(struct inode *inode, const char *name)
{
        int err;
        struct hfs_find_data cat_fd;
        u16 flags;
        u16 cat_entry_type;
        int is_xattr_acl_deleted;
        int is_all_xattrs_deleted;

        hfs_dbg("ino %lu, name %s\n",
                inode->i_ino, name ? name : NULL);

        if (!HFSPLUS_SB(inode->i_sb)->attr_tree)
                return -EOPNOTSUPP;

        if (!strcmp_xattr_finder_info(name))
                return -EOPNOTSUPP;

        err = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &cat_fd);
        if (err) {
                pr_err("can't init xattr find struct\n");
                return err;
        }

        err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &cat_fd);
        if (err) {
                pr_err("catalog searching failed\n");
                goto end_removexattr;
        }

        err = hfsplus_delete_attr(inode, name);
        if (err)
                goto end_removexattr;

        is_xattr_acl_deleted = !strcmp_xattr_acl(name);
        is_all_xattrs_deleted = !hfsplus_attr_exists(inode, NULL);

        if (!is_xattr_acl_deleted && !is_all_xattrs_deleted)
                goto end_removexattr;

        cat_entry_type = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset);

        if (cat_entry_type == HFSPLUS_FOLDER) {
                flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
                                offsetof(struct hfsplus_cat_folder, flags));
                if (is_xattr_acl_deleted)
                        flags &= ~HFSPLUS_ACL_EXISTS;
                if (is_all_xattrs_deleted)
                        flags &= ~HFSPLUS_XATTR_EXISTS;
                hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
                                offsetof(struct hfsplus_cat_folder, flags),
                                flags);
                hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
        } else if (cat_entry_type == HFSPLUS_FILE) {
                flags = hfs_bnode_read_u16(cat_fd.bnode, cat_fd.entryoffset +
                                offsetof(struct hfsplus_cat_file, flags));
                if (is_xattr_acl_deleted)
                        flags &= ~HFSPLUS_ACL_EXISTS;
                if (is_all_xattrs_deleted)
                        flags &= ~HFSPLUS_XATTR_EXISTS;
                hfs_bnode_write_u16(cat_fd.bnode, cat_fd.entryoffset +
                                offsetof(struct hfsplus_cat_file, flags),
                                flags);
                hfsplus_mark_inode_dirty(inode, HFSPLUS_I_CAT_DIRTY);
        } else {
                pr_err("invalid catalog entry type\n");
                err = -EIO;
                goto end_removexattr;
        }

end_removexattr:
        hfs_find_exit(&cat_fd);

        hfs_dbg("finished: err %d\n", err);

        return err;
}

static int hfsplus_osx_getxattr(const struct xattr_handler *handler,
                                struct dentry *unused, struct inode *inode,
                                const char *name, void *buffer, size_t size)
{
        /*
         * Don't allow retrieving properly prefixed attributes
         * by prepending them with "osx."
         */
        if (is_known_namespace(name))
                return -EOPNOTSUPP;

        /*
         * osx is the namespace we use to indicate an unprefixed
         * attribute on the filesystem (like the ones that OS X
         * creates), so we pass the name through unmodified (after
         * ensuring it doesn't conflict with another namespace).
         */
        return __hfsplus_getxattr(inode, name, buffer, size);
}

static int hfsplus_osx_setxattr(const struct xattr_handler *handler,
                                struct mnt_idmap *idmap,
                                struct dentry *unused, struct inode *inode,
                                const char *name, const void *buffer,
                                size_t size, int flags)
{
        /*
         * Don't allow setting properly prefixed attributes
         * by prepending them with "osx."
         */
        if (is_known_namespace(name))
                return -EOPNOTSUPP;

        /*
         * osx is the namespace we use to indicate an unprefixed
         * attribute on the filesystem (like the ones that OS X
         * creates), so we pass the name through unmodified (after
         * ensuring it doesn't conflict with another namespace).
         */
        return __hfsplus_setxattr(inode, name, buffer, size, flags);
}

const struct xattr_handler hfsplus_xattr_osx_handler = {
        .prefix = XATTR_MAC_OSX_PREFIX,
        .get    = hfsplus_osx_getxattr,
        .set    = hfsplus_osx_setxattr,
};