root/fs/hfsplus/dir.c
// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/hfsplus/dir.c
 *
 * Copyright (C) 2001
 * Brad Boyer (flar@allandria.com)
 * (C) 2003 Ardis Technologies <roman@ardistech.com>
 *
 * Handling of directories
 */

#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/nls.h>

#include "hfsplus_fs.h"
#include "hfsplus_raw.h"
#include "xattr.h"

static inline void hfsplus_instantiate(struct dentry *dentry,
                                       struct inode *inode, u32 cnid)
{
        dentry->d_fsdata = (void *)(unsigned long)cnid;
        d_instantiate(dentry, inode);
}

/* Find the entry inside dir named dentry->d_name */
static struct dentry *hfsplus_lookup(struct inode *dir, struct dentry *dentry,
                                     unsigned int flags)
{
        struct inode *inode = NULL;
        struct hfs_find_data fd;
        struct super_block *sb;
        hfsplus_cat_entry entry;
        int err;
        u32 cnid, linkid = 0;
        u16 type;

        sb = dir->i_sb;

        dentry->d_fsdata = NULL;
        err = hfs_find_init(HFSPLUS_SB(sb)->cat_tree, &fd);
        if (err)
                return ERR_PTR(err);
        err = hfsplus_cat_build_key(sb, fd.search_key, dir->i_ino,
                        &dentry->d_name);
        if (unlikely(err < 0))
                goto fail;
again:
        err = hfs_brec_read(&fd, &entry, sizeof(entry));
        if (err) {
                if (err == -ENOENT) {
                        hfs_find_exit(&fd);
                        /* No such entry */
                        inode = NULL;
                        goto out;
                }
                goto fail;
        }
        type = be16_to_cpu(entry.type);
        if (type == HFSPLUS_FOLDER) {
                if (fd.entrylength < sizeof(struct hfsplus_cat_folder)) {
                        err = -EIO;
                        goto fail;
                }
                cnid = be32_to_cpu(entry.folder.id);
                dentry->d_fsdata = (void *)(unsigned long)cnid;
        } else if (type == HFSPLUS_FILE) {
                if (fd.entrylength < sizeof(struct hfsplus_cat_file)) {
                        err = -EIO;
                        goto fail;
                }
                cnid = be32_to_cpu(entry.file.id);
                if (entry.file.user_info.fdType ==
                                cpu_to_be32(HFSP_HARDLINK_TYPE) &&
                                entry.file.user_info.fdCreator ==
                                cpu_to_be32(HFSP_HFSPLUS_CREATOR) &&
                                HFSPLUS_SB(sb)->hidden_dir &&
                                (entry.file.create_date ==
                                        HFSPLUS_I(HFSPLUS_SB(sb)->hidden_dir)->
                                                create_date ||
                                entry.file.create_date ==
                                        HFSPLUS_I(d_inode(sb->s_root))->
                                                create_date)) {
                        struct qstr str;
                        char name[32];

                        if (dentry->d_fsdata) {
                                /*
                                 * We found a link pointing to another link,
                                 * so ignore it and treat it as regular file.
                                 */
                                cnid = (unsigned long)dentry->d_fsdata;
                                linkid = 0;
                        } else {
                                dentry->d_fsdata = (void *)(unsigned long)cnid;
                                linkid =
                                        be32_to_cpu(entry.file.permissions.dev);
                                str.len = sprintf(name, "iNode%d", linkid);
                                str.name = name;
                                err = hfsplus_cat_build_key(sb, fd.search_key,
                                        HFSPLUS_SB(sb)->hidden_dir->i_ino,
                                        &str);
                                if (unlikely(err < 0))
                                        goto fail;
                                goto again;
                        }
                } else if (!dentry->d_fsdata)
                        dentry->d_fsdata = (void *)(unsigned long)cnid;
        } else {
                pr_err("invalid catalog entry type in lookup\n");
                err = -EIO;
                goto fail;
        }
        hfs_find_exit(&fd);
        inode = hfsplus_iget(dir->i_sb, cnid);
        if (IS_ERR(inode))
                return ERR_CAST(inode);
        if (S_ISREG(inode->i_mode))
                HFSPLUS_I(inode)->linkid = linkid;
out:
        return d_splice_alias(inode, dentry);
fail:
        hfs_find_exit(&fd);
        return ERR_PTR(err);
}

static int hfsplus_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;
        hfsplus_cat_entry entry;
        struct hfs_find_data fd;
        struct hfsplus_readdir_data *rd;
        u16 type;

        if (file->f_pos >= inode->i_size)
                return 0;

        err = hfs_find_init(HFSPLUS_SB(sb)->cat_tree, &fd);
        if (err)
                return err;
        strbuf = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_MAX_STRLEN + 1, GFP_KERNEL);
        if (!strbuf) {
                err = -ENOMEM;
                goto out;
        }
        hfsplus_cat_build_key_with_cnid(sb, fd.search_key, inode->i_ino);
        err = hfs_brec_find(&fd, hfs_find_rec_by_key);
        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 (be16_to_cpu(entry.type) != HFSPLUS_FOLDER_THREAD) {
                        pr_err("bad catalog folder thread\n");
                        err = -EIO;
                        goto out;
                }
                if (fd.entrylength < HFSPLUS_MIN_THREAD_SZ) {
                        pr_err("truncated catalog thread\n");
                        err = -EIO;
                        goto out;
                }
                if (!dir_emit(ctx, "..", 2,
                            be32_to_cpu(entry.thread.parentID), 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.parent) != 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 = be16_to_cpu(entry.type);
                len = NLS_MAX_CHARSET_SIZE * HFSPLUS_MAX_STRLEN;
                err = hfsplus_uni2asc_str(sb, &fd.key->cat.name, strbuf, &len);
                if (err)
                        goto out;
                if (type == HFSPLUS_FOLDER) {
                        if (fd.entrylength <
                                        sizeof(struct hfsplus_cat_folder)) {
                                pr_err("small dir entry\n");
                                err = -EIO;
                                goto out;
                        }
                        if (HFSPLUS_SB(sb)->hidden_dir &&
                            HFSPLUS_SB(sb)->hidden_dir->i_ino ==
                                        be32_to_cpu(entry.folder.id))
                                goto next;
                        if (!dir_emit(ctx, strbuf, len,
                                    be32_to_cpu(entry.folder.id), DT_DIR))
                                break;
                } else if (type == HFSPLUS_FILE) {
                        u16 mode;
                        unsigned type = DT_UNKNOWN;

                        if (fd.entrylength < sizeof(struct hfsplus_cat_file)) {
                                pr_err("small file entry\n");
                                err = -EIO;
                                goto out;
                        }

                        mode = be16_to_cpu(entry.file.permissions.mode);
                        if (S_ISREG(mode))
                                type = DT_REG;
                        else if (S_ISLNK(mode))
                                type = DT_LNK;
                        else if (S_ISFIFO(mode))
                                type = DT_FIFO;
                        else if (S_ISCHR(mode))
                                type = DT_CHR;
                        else if (S_ISBLK(mode))
                                type = DT_BLK;
                        else if (S_ISSOCK(mode))
                                type = DT_SOCK;

                        if (!dir_emit(ctx, strbuf, len,
                                      be32_to_cpu(entry.file.id), type))
                                break;
                } else {
                        pr_err("bad catalog entry type\n");
                        err = -EIO;
                        goto out;
                }
next:
                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_obj(struct hfsplus_readdir_data);
                if (!rd) {
                        err = -ENOMEM;
                        goto out;
                }
                file->private_data = rd;
                rd->file = file;
                spin_lock(&HFSPLUS_I(inode)->open_dir_lock);
                list_add(&rd->list, &HFSPLUS_I(inode)->open_dir_list);
                spin_unlock(&HFSPLUS_I(inode)->open_dir_lock);
        }
        /*
         * Can be done after the list insertion; exclusion with
         * hfsplus_delete_cat() is provided by directory lock.
         */
        memcpy(&rd->key, fd.key, sizeof(struct hfsplus_cat_key));
out:
        kfree(strbuf);
        hfs_find_exit(&fd);
        return err;
}

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

static int hfsplus_link(struct dentry *src_dentry, struct inode *dst_dir,
                        struct dentry *dst_dentry)
{
        struct hfsplus_sb_info *sbi = HFSPLUS_SB(dst_dir->i_sb);
        struct inode *inode = d_inode(src_dentry);
        struct inode *src_dir = d_inode(src_dentry->d_parent);
        struct qstr str;
        char name[32];
        u32 cnid, id;
        int res;

        if (HFSPLUS_IS_RSRC(inode))
                return -EPERM;
        if (!S_ISREG(inode->i_mode))
                return -EPERM;

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

        mutex_lock(&sbi->vh_mutex);
        if (inode->i_ino == (u32)(unsigned long)src_dentry->d_fsdata) {
                for (;;) {
                        get_random_bytes(&id, sizeof(cnid));
                        id &= 0x3fffffff;
                        str.name = name;
                        str.len = sprintf(name, "iNode%d", id);
                        res = hfsplus_rename_cat(inode->i_ino,
                                                 src_dir, &src_dentry->d_name,
                                                 sbi->hidden_dir, &str);
                        if (!res)
                                break;
                        if (res != -EEXIST)
                                goto out;
                }
                HFSPLUS_I(inode)->linkid = id;
                cnid = sbi->next_cnid++;
                src_dentry->d_fsdata = (void *)(unsigned long)cnid;
                res = hfsplus_create_cat(cnid, src_dir,
                                         &src_dentry->d_name, inode);
                if (res)
                        /* panic? */
                        goto out;
                sbi->file_count++;
        }
        cnid = sbi->next_cnid++;
        res = hfsplus_create_cat(cnid, dst_dir, &dst_dentry->d_name, inode);
        if (res)
                goto out;

        inc_nlink(inode);
        hfsplus_instantiate(dst_dentry, inode, cnid);
        ihold(inode);
        inode_set_ctime_current(inode);
        mark_inode_dirty(inode);
        sbi->file_count++;
        hfsplus_mark_mdb_dirty(dst_dir->i_sb);

        res = hfsplus_cat_write_inode(src_dir);
        if (res)
                goto out;

        res = hfsplus_cat_write_inode(dst_dir);
        if (res)
                goto out;

        res = hfsplus_cat_write_inode(sbi->hidden_dir);
        if (res)
                goto out;

        res = hfsplus_cat_write_inode(inode);

out:
        mutex_unlock(&sbi->vh_mutex);
        return res;
}

static int hfsplus_unlink(struct inode *dir, struct dentry *dentry)
{
        struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
        struct inode *inode = d_inode(dentry);
        struct qstr str;
        char name[32];
        u32 cnid;
        int res;

        if (HFSPLUS_IS_RSRC(inode))
                return -EPERM;

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

        mutex_lock(&sbi->vh_mutex);
        cnid = (u32)(unsigned long)dentry->d_fsdata;
        if (inode->i_ino == cnid &&
            atomic_read(&HFSPLUS_I(inode)->opencnt)) {
                str.name = name;
                str.len = sprintf(name, "temp%lu", inode->i_ino);
                res = hfsplus_rename_cat(inode->i_ino,
                                         dir, &dentry->d_name,
                                         sbi->hidden_dir, &str);
                if (!res) {
                        inode->i_flags |= S_DEAD;
                        drop_nlink(inode);
                }
                goto out;
        }
        res = hfsplus_delete_cat(cnid, dir, &dentry->d_name);
        if (res)
                goto out;

        if (inode->i_nlink > 0)
                drop_nlink(inode);
        if (inode->i_ino == cnid)
                clear_nlink(inode);
        if (!inode->i_nlink) {
                if (inode->i_ino != cnid) {
                        sbi->file_count--;
                        if (!atomic_read(&HFSPLUS_I(inode)->opencnt)) {
                                res = hfsplus_delete_cat(inode->i_ino,
                                                         sbi->hidden_dir,
                                                         NULL);
                                if (!res)
                                        hfsplus_delete_inode(inode);
                        } else
                                inode->i_flags |= S_DEAD;
                } else
                        hfsplus_delete_inode(inode);
        } else
                sbi->file_count--;
        inode_set_ctime_current(inode);
        mark_inode_dirty(inode);
out:
        if (!res) {
                res = hfsplus_cat_write_inode(dir);
                if (!res) {
                        res = hfsplus_cat_write_inode(sbi->hidden_dir);
                        if (!res)
                                res = hfsplus_cat_write_inode(inode);
                }
        }

        mutex_unlock(&sbi->vh_mutex);
        return res;
}

static int hfsplus_rmdir(struct inode *dir, struct dentry *dentry)
{
        struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
        struct inode *inode = d_inode(dentry);
        int res;

        if (inode->i_size != 2)
                return -ENOTEMPTY;

        mutex_lock(&sbi->vh_mutex);
        res = hfsplus_delete_cat(inode->i_ino, dir, &dentry->d_name);
        if (res)
                goto out;
        clear_nlink(inode);
        inode_set_ctime_current(inode);
        hfsplus_delete_inode(inode);
        mark_inode_dirty(inode);

        res = hfsplus_cat_write_inode(dir);
out:
        mutex_unlock(&sbi->vh_mutex);
        return res;
}

static int hfsplus_symlink(struct mnt_idmap *idmap, struct inode *dir,
                           struct dentry *dentry, const char *symname)
{
        struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
        struct inode *inode;
        int res = -ENOMEM;

        mutex_lock(&sbi->vh_mutex);
        inode = hfsplus_new_inode(dir->i_sb, dir, S_IFLNK | S_IRWXUGO);
        if (!inode)
                goto out;

        res = page_symlink(inode, symname, strlen(symname) + 1);
        if (res)
                goto out_err;

        res = hfsplus_create_cat(inode->i_ino, dir, &dentry->d_name, inode);
        if (res)
                goto out_err;

        res = hfsplus_init_security(inode, dir, &dentry->d_name);
        if (res == -EOPNOTSUPP)
                res = 0; /* Operation is not supported. */
        else if (res) {
                /* Try to delete anyway without error analysis. */
                hfsplus_delete_cat(inode->i_ino, dir, &dentry->d_name);
                goto out_err;
        }

        hfsplus_instantiate(dentry, inode, inode->i_ino);
        mark_inode_dirty(inode);

        res = hfsplus_cat_write_inode(dir);
        if (res)
                goto out;

        res = hfsplus_cat_write_inode(inode);
        goto out;

out_err:
        clear_nlink(inode);
        hfsplus_delete_inode(inode);
        iput(inode);
out:
        mutex_unlock(&sbi->vh_mutex);
        return res;
}

static int hfsplus_mknod(struct mnt_idmap *idmap, struct inode *dir,
                         struct dentry *dentry, umode_t mode, dev_t rdev)
{
        struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
        struct inode *inode;
        int res = -ENOMEM;

        mutex_lock(&sbi->vh_mutex);
        inode = hfsplus_new_inode(dir->i_sb, dir, mode);
        if (!inode)
                goto out;

        if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode))
                init_special_inode(inode, mode, rdev);

        res = hfsplus_create_cat(inode->i_ino, dir, &dentry->d_name, inode);
        if (res)
                goto failed_mknod;

        res = hfsplus_init_security(inode, dir, &dentry->d_name);
        if (res == -EOPNOTSUPP)
                res = 0; /* Operation is not supported. */
        else if (res) {
                /* Try to delete anyway without error analysis. */
                hfsplus_delete_cat(inode->i_ino, dir, &dentry->d_name);
                goto failed_mknod;
        }

        hfsplus_instantiate(dentry, inode, inode->i_ino);
        mark_inode_dirty(inode);

        res = hfsplus_cat_write_inode(dir);
        if (res)
                goto out;

        res = hfsplus_cat_write_inode(inode);
        goto out;

failed_mknod:
        clear_nlink(inode);
        hfsplus_delete_inode(inode);
        iput(inode);
out:
        mutex_unlock(&sbi->vh_mutex);
        return res;
}

static int hfsplus_create(struct mnt_idmap *idmap, struct inode *dir,
                          struct dentry *dentry, umode_t mode, bool excl)
{
        return hfsplus_mknod(&nop_mnt_idmap, dir, dentry, mode, 0);
}

static struct dentry *hfsplus_mkdir(struct mnt_idmap *idmap, struct inode *dir,
                                    struct dentry *dentry, umode_t mode)
{
        return ERR_PTR(hfsplus_mknod(&nop_mnt_idmap, dir, dentry, mode | S_IFDIR, 0));
}

static int hfsplus_rename(struct mnt_idmap *idmap,
                          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)) {
                if (d_is_dir(new_dentry))
                        res = hfsplus_rmdir(new_dir, new_dentry);
                else
                        res = hfsplus_unlink(new_dir, new_dentry);
                if (res)
                        return res;
        }

        res = hfsplus_rename_cat((u32)(unsigned long)old_dentry->d_fsdata,
                                 old_dir, &old_dentry->d_name,
                                 new_dir, &new_dentry->d_name);
        if (!res) {
                new_dentry->d_fsdata = old_dentry->d_fsdata;

                res = hfsplus_cat_write_inode(old_dir);
                if (!res)
                        res = hfsplus_cat_write_inode(new_dir);
        }
        return res;
}

const struct inode_operations hfsplus_dir_inode_operations = {
        .lookup                 = hfsplus_lookup,
        .create                 = hfsplus_create,
        .link                   = hfsplus_link,
        .unlink                 = hfsplus_unlink,
        .mkdir                  = hfsplus_mkdir,
        .rmdir                  = hfsplus_rmdir,
        .symlink                = hfsplus_symlink,
        .mknod                  = hfsplus_mknod,
        .rename                 = hfsplus_rename,
        .getattr                = hfsplus_getattr,
        .listxattr              = hfsplus_listxattr,
        .fileattr_get           = hfsplus_fileattr_get,
        .fileattr_set           = hfsplus_fileattr_set,
};

const struct file_operations hfsplus_dir_operations = {
        .fsync          = hfsplus_file_fsync,
        .read           = generic_read_dir,
        .iterate_shared = hfsplus_readdir,
        .unlocked_ioctl = hfsplus_ioctl,
        .llseek         = generic_file_llseek,
        .release        = hfsplus_dir_release,
};