/*
 *  linux/fs/hfs/dir.c
 *
 * Copyright (C) 1995-1997  Paul H. Hargrove
 * (C) 2003 Ardis Technologies <roman@ardistech.com>
 * This file may be distributed under the terms of the GNU General Public License.
 *
 * This file contains directory-related functions independent of which
 * scheme is being used to represent forks.
 *
 * Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
 */

#include "hfs_fs.h"
#include "btree.h"

/*
 * hfs_lookup()
 */
static struct dentry *hfs_lookup(struct inode *dir, struct dentry *dentry,
                                 unsigned int flags)
{
        hfs_cat_rec rec;
        struct hfs_find_data fd;
        struct inode *inode = NULL;
        int res;

        res = hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
        if (res)
                return ERR_PTR(res);
        hfs_cat_build_key(dir->i_sb, fd.search_key, dir->i_ino, &dentry->d_name);
        res = hfs_brec_read(&fd, &rec, sizeof(rec));
        if (res) {
                if (res != -ENOENT)
                        inode = ERR_PTR(res);
        } else {
                inode = hfs_iget(dir->i_sb, &fd.search_key->cat, &rec);
                if (!inode)
                        inode = ERR_PTR(-EACCES);
        }
        hfs_find_exit(&fd);
        return d_splice_alias(inode, dentry);
}

/*
 * hfs_readdir
 */
static int hfs_readdir(struct file *file, struct dir_context *ctx)
{
        struct inode *inode = file_inode(file);
        struct super_block *sb = inode->i_sb;
        int len, err;
        char strbuf[HFS_MAX_NAMELEN];
        union hfs_cat_rec entry;
        struct hfs_find_data fd;
        struct hfs_readdir_data *rd;
        u16 type;

        if (ctx->pos >= inode->i_size)
                return 0;

        err = hfs_find_init(HFS_SB(sb)->cat_tree, &fd);
        if (err)
                return err;
        hfs_cat_build_key(sb, fd.search_key, inode->i_ino, NULL);
        err = hfs_brec_find(&fd);
        if (err)
                goto out;

        if (ctx->pos == 0) {
                /* This is completely artificial... */
                if (!dir_emit_dot(file, ctx))
                        goto out;
                ctx->pos = 1;
        }
        if (ctx->pos == 1) {
                if (fd.entrylength > sizeof(entry) || fd.entrylength < 0) {
                        err = -EIO;
                        goto out;
                }

                hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength);
                if (entry.type != HFS_CDR_THD) {
                        pr_err("bad catalog folder thread\n");
                        err = -EIO;
                        goto out;
                }
                //if (fd.entrylength < HFS_MIN_THREAD_SZ) {
                //      pr_err("truncated catalog thread\n");
                //      err = -EIO;
                //      goto out;
                //}
                if (!dir_emit(ctx, "..", 2,
                            be32_to_cpu(entry.thread.ParID), DT_DIR))
                        goto out;
                ctx->pos = 2;
        }
        if (ctx->pos >= inode->i_size)
                goto out;
        err = hfs_brec_goto(&fd, ctx->pos - 1);
        if (err)
                goto out;

        for (;;) {
                if (be32_to_cpu(fd.key->cat.ParID) != inode->i_ino) {
                        pr_err("walked past end of dir\n");
                        err = -EIO;
                        goto out;
                }

                if (fd.entrylength > sizeof(entry) || fd.entrylength < 0) {
                        err = -EIO;
                        goto out;
                }

                hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength);
                type = entry.type;
                len = hfs_mac2asc(sb, strbuf, &fd.key->cat.CName);
                if (type == HFS_CDR_DIR) {
                        if (fd.entrylength < sizeof(struct hfs_cat_dir)) {
                                pr_err("small dir entry\n");
                                err = -EIO;
                                goto out;
                        }
                        if (!dir_emit(ctx, strbuf, len,
                                    be32_to_cpu(entry.dir.DirID), DT_DIR))
                                break;
                } else if (type == HFS_CDR_FIL) {
                        if (fd.entrylength < sizeof(struct hfs_cat_file)) {
                                pr_err("small file entry\n");
                                err = -EIO;
                                goto out;
                        }
                        if (!dir_emit(ctx, strbuf, len,
                                    be32_to_cpu(entry.file.FlNum), DT_REG))
                                break;
                } else {
                        pr_err("bad catalog entry type %d\n", type);
                        err = -EIO;
                        goto out;
                }
                ctx->pos++;
                if (ctx->pos >= inode->i_size)
                        goto out;
                err = hfs_brec_goto(&fd, 1);
                if (err)
                        goto out;
        }
        rd = file->private_data;
        if (!rd) {
                rd = kmalloc(sizeof(struct hfs_readdir_data), GFP_KERNEL);
                if (!rd) {
                        err = -ENOMEM;
                        goto out;
                }
                file->private_data = rd;
                rd->file = file;
                spin_lock(&HFS_I(inode)->open_dir_lock);
                list_add(&rd->list, &HFS_I(inode)->open_dir_list);
                spin_unlock(&HFS_I(inode)->open_dir_lock);
        }
        /*
         * Can be done after the list insertion; exclusion with
         * hfs_delete_cat() is provided by directory lock.
         */
        memcpy(&rd->key, &fd.key->cat, sizeof(struct hfs_cat_key));
out:
        hfs_find_exit(&fd);
        return err;
}

static int hfs_dir_release(struct inode *inode, struct file *file)
{
        struct hfs_readdir_data *rd = file->private_data;
        if (rd) {
                spin_lock(&HFS_I(inode)->open_dir_lock);
                list_del(&rd->list);
                spin_unlock(&HFS_I(inode)->open_dir_lock);
                kfree(rd);
        }
        return 0;
}

/*
 * hfs_create()
 *
 * This is the create() entry in the inode_operations structure for
 * regular HFS directories.  The purpose is to create a new file in
 * a directory and return a corresponding inode, given the inode for
 * the directory and the name (and its length) of the new file.
 */
static int hfs_create(struct user_namespace *mnt_userns, struct inode *dir,
                      struct dentry *dentry, umode_t mode, bool excl)
{
        struct inode *inode;
        int res;

        inode = hfs_new_inode(dir, &dentry->d_name, mode);
        if (!inode)
                return -ENOMEM;

        res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode);
        if (res) {
                clear_nlink(inode);
                hfs_delete_inode(inode);
                iput(inode);
                return res;
        }
        d_instantiate(dentry, inode);
        mark_inode_dirty(inode);
        return 0;
}

/*
 * hfs_mkdir()
 *
 * This is the mkdir() entry in the inode_operations structure for
 * regular HFS directories.  The purpose is to create a new directory
 * in a directory, given the inode for the parent directory and the
 * name (and its length) of the new directory.
 */
static int hfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
                     struct dentry *dentry, umode_t mode)
{
        struct inode *inode;
        int res;

        inode = hfs_new_inode(dir, &dentry->d_name, S_IFDIR | mode);
        if (!inode)
                return -ENOMEM;

        res = hfs_cat_create(inode->i_ino, dir, &dentry->d_name, inode);
        if (res) {
                clear_nlink(inode);
                hfs_delete_inode(inode);
                iput(inode);
                return res;
        }
        d_instantiate(dentry, inode);
        mark_inode_dirty(inode);
        return 0;
}

/*
 * hfs_remove()
 *
 * This serves as both unlink() and rmdir() in the inode_operations
 * structure for regular HFS directories.  The purpose is to delete
 * an existing child, given the inode for the parent directory and
 * the name (and its length) of the existing directory.
 *
 * HFS does not have hardlinks, so both rmdir and unlink set the
 * link count to 0.  The only difference is the emptiness check.
 */
static int hfs_remove(struct inode *dir, struct dentry *dentry)
{
        struct inode *inode = d_inode(dentry);
        int res;

        if (S_ISDIR(inode->i_mode) && inode->i_size != 2)
                return -ENOTEMPTY;
        res = hfs_cat_delete(inode->i_ino, dir, &dentry->d_name);
        if (res)
                return res;
        clear_nlink(inode);
        inode->i_ctime = current_time(inode);
        hfs_delete_inode(inode);
        mark_inode_dirty(inode);
        return 0;
}

/*
 * hfs_rename()
 *
 * This is the rename() entry in the inode_operations structure for
 * regular HFS directories.  The purpose is to rename an existing
 * file or directory, given the inode for the current directory and
 * the name (and its length) of the existing file/directory and the
 * inode for the new directory and the name (and its length) of the
 * new file/directory.
 * XXX: how do you handle must_be dir?
 */
static int hfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
                      struct dentry *old_dentry, struct inode *new_dir,
                      struct dentry *new_dentry, unsigned int flags)
{
        int res;

        if (flags & ~RENAME_NOREPLACE)
                return -EINVAL;

        /* Unlink destination if it already exists */
        if (d_really_is_positive(new_dentry)) {
                res = hfs_remove(new_dir, new_dentry);
                if (res)
                        return res;
        }

        res = hfs_cat_move(d_inode(old_dentry)->i_ino,
                           old_dir, &old_dentry->d_name,
                           new_dir, &new_dentry->d_name);
        if (!res)
                hfs_cat_build_key(old_dir->i_sb,
                                  (btree_key *)&HFS_I(d_inode(old_dentry))->cat_key,
                                  new_dir->i_ino, &new_dentry->d_name);
        return res;
}

const struct file_operations hfs_dir_operations = {
        .read           = generic_read_dir,
        .iterate_shared = hfs_readdir,
        .llseek         = generic_file_llseek,
        .release        = hfs_dir_release,
};

const struct inode_operations hfs_dir_inode_operations = {
        .create         = hfs_create,
        .lookup         = hfs_lookup,
        .unlink         = hfs_remove,
        .mkdir          = hfs_mkdir,
        .rmdir          = hfs_remove,
        .rename         = hfs_rename,
        .setattr        = hfs_inode_setattr,
};