WSL2-Linux-Kernel/fs/hpfs/namei.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/hpfs/namei.c
 *
 *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
 *
 *  adding & removing files & directories
 */
#include <linux/sched.h>
#include "hpfs_fn.h"

static void hpfs_update_directory_times(struct inode *dir)
{
	time64_t t = local_to_gmt(dir->i_sb, local_get_seconds(dir->i_sb));
	if (t == dir->i_mtime.tv_sec &&
	    t == dir->i_ctime.tv_sec)
		return;
	dir->i_mtime.tv_sec = dir->i_ctime.tv_sec = t;
	dir->i_mtime.tv_nsec = dir->i_ctime.tv_nsec = 0;
	hpfs_write_inode_nolock(dir);
}

static int hpfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
		      struct dentry *dentry, umode_t mode)
{
	const unsigned char *name = dentry->d_name.name;
	unsigned len = dentry->d_name.len;
	struct quad_buffer_head qbh0;
	struct buffer_head *bh;
	struct hpfs_dirent *de;
	struct fnode *fnode;
	struct dnode *dnode;
	struct inode *result;
	fnode_secno fno;
	dnode_secno dno;
	int r;
	struct hpfs_dirent dee;
	int err;
	if ((err = hpfs_chk_name(name, &len))) return err==-ENOENT ? -EINVAL : err;
	hpfs_lock(dir->i_sb);
	err = -ENOSPC;
	fnode = hpfs_alloc_fnode(dir->i_sb, hpfs_i(dir)->i_dno, &fno, &bh);
	if (!fnode)
		goto bail;
	dnode = hpfs_alloc_dnode(dir->i_sb, fno, &dno, &qbh0);
	if (!dnode)
		goto bail1;
	memset(&dee, 0, sizeof dee);
	dee.directory = 1;
	if (!(mode & 0222)) dee.read_only = 1;
	/*dee.archive = 0;*/
	dee.hidden = name[0] == '.';
	dee.fnode = cpu_to_le32(fno);
	dee.creation_date = dee.write_date = dee.read_date = cpu_to_le32(local_get_seconds(dir->i_sb));
	result = new_inode(dir->i_sb);
	if (!result)
		goto bail2;
	hpfs_init_inode(result);
	result->i_ino = fno;
	hpfs_i(result)->i_parent_dir = dir->i_ino;
	hpfs_i(result)->i_dno = dno;
	result->i_ctime.tv_sec = result->i_mtime.tv_sec = result->i_atime.tv_sec = local_to_gmt(dir->i_sb, le32_to_cpu(dee.creation_date));
	result->i_ctime.tv_nsec = 0; 
	result->i_mtime.tv_nsec = 0; 
	result->i_atime.tv_nsec = 0; 
	hpfs_i(result)->i_ea_size = 0;
	result->i_mode |= S_IFDIR;
	result->i_op = &hpfs_dir_iops;
	result->i_fop = &hpfs_dir_ops;
	result->i_blocks = 4;
	result->i_size = 2048;
	set_nlink(result, 2);
	if (dee.read_only)
		result->i_mode &= ~0222;

	r = hpfs_add_dirent(dir, name, len, &dee);
	if (r == 1)
		goto bail3;
	if (r == -1) {
		err = -EEXIST;
		goto bail3;
	}
	fnode->len = len;
	memcpy(fnode->name, name, len > 15 ? 15 : len);
	fnode->up = cpu_to_le32(dir->i_ino);
	fnode->flags |= FNODE_dir;
	fnode->btree.n_free_nodes = 7;
	fnode->btree.n_used_nodes = 1;
	fnode->btree.first_free = cpu_to_le16(0x14);
	fnode->u.external[0].disk_secno = cpu_to_le32(dno);
	fnode->u.external[0].file_secno = cpu_to_le32(-1);
	dnode->root_dnode = 1;
	dnode->up = cpu_to_le32(fno);
	de = hpfs_add_de(dir->i_sb, dnode, "\001\001", 2, 0);
	de->creation_date = de->write_date = de->read_date = cpu_to_le32(local_get_seconds(dir->i_sb));
	if (!(mode & 0222)) de->read_only = 1;
	de->first = de->directory = 1;
	/*de->hidden = de->system = 0;*/
	de->fnode = cpu_to_le32(fno);
	mark_buffer_dirty(bh);
	brelse(bh);
	hpfs_mark_4buffers_dirty(&qbh0);
	hpfs_brelse4(&qbh0);
	inc_nlink(dir);
	insert_inode_hash(result);

	if (!uid_eq(result->i_uid, current_fsuid()) ||
	    !gid_eq(result->i_gid, current_fsgid()) ||
	    result->i_mode != (mode | S_IFDIR)) {
		result->i_uid = current_fsuid();
		result->i_gid = current_fsgid();
		result->i_mode = mode | S_IFDIR;
		hpfs_write_inode_nolock(result);
	}
	hpfs_update_directory_times(dir);
	d_instantiate(dentry, result);
	hpfs_unlock(dir->i_sb);
	return 0;
bail3:
	iput(result);
bail2:
	hpfs_brelse4(&qbh0);
	hpfs_free_dnode(dir->i_sb, dno);
bail1:
	brelse(bh);
	hpfs_free_sectors(dir->i_sb, fno, 1);
bail:
	hpfs_unlock(dir->i_sb);
	return err;
}

static int hpfs_create(struct user_namespace *mnt_userns, struct inode *dir,
		       struct dentry *dentry, umode_t mode, bool excl)
{
	const unsigned char *name = dentry->d_name.name;
	unsigned len = dentry->d_name.len;
	struct inode *result = NULL;
	struct buffer_head *bh;
	struct fnode *fnode;
	fnode_secno fno;
	int r;
	struct hpfs_dirent dee;
	int err;
	if ((err = hpfs_chk_name(name, &len)))
		return err==-ENOENT ? -EINVAL : err;
	hpfs_lock(dir->i_sb);
	err = -ENOSPC;
	fnode = hpfs_alloc_fnode(dir->i_sb, hpfs_i(dir)->i_dno, &fno, &bh);
	if (!fnode)
		goto bail;
	memset(&dee, 0, sizeof dee);
	if (!(mode & 0222)) dee.read_only = 1;
	dee.archive = 1;
	dee.hidden = name[0] == '.';
	dee.fnode = cpu_to_le32(fno);
	dee.creation_date = dee.write_date = dee.read_date = cpu_to_le32(local_get_seconds(dir->i_sb));

	result = new_inode(dir->i_sb);
	if (!result)
		goto bail1;
	
	hpfs_init_inode(result);
	result->i_ino = fno;
	result->i_mode |= S_IFREG;
	result->i_mode &= ~0111;
	result->i_op = &hpfs_file_iops;
	result->i_fop = &hpfs_file_ops;
	set_nlink(result, 1);
	hpfs_i(result)->i_parent_dir = dir->i_ino;
	result->i_ctime.tv_sec = result->i_mtime.tv_sec = result->i_atime.tv_sec = local_to_gmt(dir->i_sb, le32_to_cpu(dee.creation_date));
	result->i_ctime.tv_nsec = 0;
	result->i_mtime.tv_nsec = 0;
	result->i_atime.tv_nsec = 0;
	hpfs_i(result)->i_ea_size = 0;
	if (dee.read_only)
		result->i_mode &= ~0222;
	result->i_blocks = 1;
	result->i_size = 0;
	result->i_data.a_ops = &hpfs_aops;
	hpfs_i(result)->mmu_private = 0;

	r = hpfs_add_dirent(dir, name, len, &dee);
	if (r == 1)
		goto bail2;
	if (r == -1) {
		err = -EEXIST;
		goto bail2;
	}
	fnode->len = len;
	memcpy(fnode->name, name, len > 15 ? 15 : len);
	fnode->up = cpu_to_le32(dir->i_ino);
	mark_buffer_dirty(bh);
	brelse(bh);

	insert_inode_hash(result);

	if (!uid_eq(result->i_uid, current_fsuid()) ||
	    !gid_eq(result->i_gid, current_fsgid()) ||
	    result->i_mode != (mode | S_IFREG)) {
		result->i_uid = current_fsuid();
		result->i_gid = current_fsgid();
		result->i_mode = mode | S_IFREG;
		hpfs_write_inode_nolock(result);
	}
	hpfs_update_directory_times(dir);
	d_instantiate(dentry, result);
	hpfs_unlock(dir->i_sb);
	return 0;

bail2:
	iput(result);
bail1:
	brelse(bh);
	hpfs_free_sectors(dir->i_sb, fno, 1);
bail:
	hpfs_unlock(dir->i_sb);
	return err;
}

static int hpfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
		      struct dentry *dentry, umode_t mode, dev_t rdev)
{
	const unsigned char *name = dentry->d_name.name;
	unsigned len = dentry->d_name.len;
	struct buffer_head *bh;
	struct fnode *fnode;
	fnode_secno fno;
	int r;
	struct hpfs_dirent dee;
	struct inode *result = NULL;
	int err;
	if ((err = hpfs_chk_name(name, &len))) return err==-ENOENT ? -EINVAL : err;
	if (hpfs_sb(dir->i_sb)->sb_eas < 2) return -EPERM;
	hpfs_lock(dir->i_sb);
	err = -ENOSPC;
	fnode = hpfs_alloc_fnode(dir->i_sb, hpfs_i(dir)->i_dno, &fno, &bh);
	if (!fnode)
		goto bail;
	memset(&dee, 0, sizeof dee);
	if (!(mode & 0222)) dee.read_only = 1;
	dee.archive = 1;
	dee.hidden = name[0] == '.';
	dee.fnode = cpu_to_le32(fno);
	dee.creation_date = dee.write_date = dee.read_date = cpu_to_le32(local_get_seconds(dir->i_sb));

	result = new_inode(dir->i_sb);
	if (!result)
		goto bail1;

	hpfs_init_inode(result);
	result->i_ino = fno;
	hpfs_i(result)->i_parent_dir = dir->i_ino;
	result->i_ctime.tv_sec = result->i_mtime.tv_sec = result->i_atime.tv_sec = local_to_gmt(dir->i_sb, le32_to_cpu(dee.creation_date));
	result->i_ctime.tv_nsec = 0;
	result->i_mtime.tv_nsec = 0;
	result->i_atime.tv_nsec = 0;
	hpfs_i(result)->i_ea_size = 0;
	result->i_uid = current_fsuid();
	result->i_gid = current_fsgid();
	set_nlink(result, 1);
	result->i_size = 0;
	result->i_blocks = 1;
	init_special_inode(result, mode, rdev);

	r = hpfs_add_dirent(dir, name, len, &dee);
	if (r == 1)
		goto bail2;
	if (r == -1) {
		err = -EEXIST;
		goto bail2;
	}
	fnode->len = len;
	memcpy(fnode->name, name, len > 15 ? 15 : len);
	fnode->up = cpu_to_le32(dir->i_ino);
	mark_buffer_dirty(bh);

	insert_inode_hash(result);

	hpfs_write_inode_nolock(result);
	hpfs_update_directory_times(dir);
	d_instantiate(dentry, result);
	brelse(bh);
	hpfs_unlock(dir->i_sb);
	return 0;
bail2:
	iput(result);
bail1:
	brelse(bh);
	hpfs_free_sectors(dir->i_sb, fno, 1);
bail:
	hpfs_unlock(dir->i_sb);
	return err;
}

static int hpfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
			struct dentry *dentry, const char *symlink)
{
	const unsigned char *name = dentry->d_name.name;
	unsigned len = dentry->d_name.len;
	struct buffer_head *bh;
	struct fnode *fnode;
	fnode_secno fno;
	int r;
	struct hpfs_dirent dee;
	struct inode *result;
	int err;
	if ((err = hpfs_chk_name(name, &len))) return err==-ENOENT ? -EINVAL : err;
	hpfs_lock(dir->i_sb);
	if (hpfs_sb(dir->i_sb)->sb_eas < 2) {
		hpfs_unlock(dir->i_sb);
		return -EPERM;
	}
	err = -ENOSPC;
	fnode = hpfs_alloc_fnode(dir->i_sb, hpfs_i(dir)->i_dno, &fno, &bh);
	if (!fnode)
		goto bail;
	memset(&dee, 0, sizeof dee);
	dee.archive = 1;
	dee.hidden = name[0] == '.';
	dee.fnode = cpu_to_le32(fno);
	dee.creation_date = dee.write_date = dee.read_date = cpu_to_le32(local_get_seconds(dir->i_sb));

	result = new_inode(dir->i_sb);
	if (!result)
		goto bail1;
	result->i_ino = fno;
	hpfs_init_inode(result);
	hpfs_i(result)->i_parent_dir = dir->i_ino;
	result->i_ctime.tv_sec = result->i_mtime.tv_sec = result->i_atime.tv_sec = local_to_gmt(dir->i_sb, le32_to_cpu(dee.creation_date));
	result->i_ctime.tv_nsec = 0;
	result->i_mtime.tv_nsec = 0;
	result->i_atime.tv_nsec = 0;
	hpfs_i(result)->i_ea_size = 0;
	result->i_mode = S_IFLNK | 0777;
	result->i_uid = current_fsuid();
	result->i_gid = current_fsgid();
	result->i_blocks = 1;
	set_nlink(result, 1);
	result->i_size = strlen(symlink);
	inode_nohighmem(result);
	result->i_op = &page_symlink_inode_operations;
	result->i_data.a_ops = &hpfs_symlink_aops;

	r = hpfs_add_dirent(dir, name, len, &dee);
	if (r == 1)
		goto bail2;
	if (r == -1) {
		err = -EEXIST;
		goto bail2;
	}
	fnode->len = len;
	memcpy(fnode->name, name, len > 15 ? 15 : len);
	fnode->up = cpu_to_le32(dir->i_ino);
	hpfs_set_ea(result, fnode, "SYMLINK", symlink, strlen(symlink));
	mark_buffer_dirty(bh);
	brelse(bh);

	insert_inode_hash(result);

	hpfs_write_inode_nolock(result);
	hpfs_update_directory_times(dir);
	d_instantiate(dentry, result);
	hpfs_unlock(dir->i_sb);
	return 0;
bail2:
	iput(result);
bail1:
	brelse(bh);
	hpfs_free_sectors(dir->i_sb, fno, 1);
bail:
	hpfs_unlock(dir->i_sb);
	return err;
}

static int hpfs_unlink(struct inode *dir, struct dentry *dentry)
{
	const unsigned char *name = dentry->d_name.name;
	unsigned len = dentry->d_name.len;
	struct quad_buffer_head qbh;
	struct hpfs_dirent *de;
	struct inode *inode = d_inode(dentry);
	dnode_secno dno;
	int r;
	int err;

	hpfs_lock(dir->i_sb);
	hpfs_adjust_length(name, &len);

	err = -ENOENT;
	de = map_dirent(dir, hpfs_i(dir)->i_dno, name, len, &dno, &qbh);
	if (!de)
		goto out;

	err = -EPERM;
	if (de->first)
		goto out1;

	err = -EISDIR;
	if (de->directory)
		goto out1;

	r = hpfs_remove_dirent(dir, dno, de, &qbh, 1);
	switch (r) {
	case 1:
		hpfs_error(dir->i_sb, "there was error when removing dirent");
		err = -EFSERROR;
		break;
	case 2:		/* no space for deleting */
		err = -ENOSPC;
		break;
	default:
		drop_nlink(inode);
		err = 0;
	}
	goto out;

out1:
	hpfs_brelse4(&qbh);
out:
	if (!err)
		hpfs_update_directory_times(dir);
	hpfs_unlock(dir->i_sb);
	return err;
}

static int hpfs_rmdir(struct inode *dir, struct dentry *dentry)
{
	const unsigned char *name = dentry->d_name.name;
	unsigned len = dentry->d_name.len;
	struct quad_buffer_head qbh;
	struct hpfs_dirent *de;
	struct inode *inode = d_inode(dentry);
	dnode_secno dno;
	int n_items = 0;
	int err;
	int r;

	hpfs_adjust_length(name, &len);
	hpfs_lock(dir->i_sb);
	err = -ENOENT;
	de = map_dirent(dir, hpfs_i(dir)->i_dno, name, len, &dno, &qbh);
	if (!de)
		goto out;

	err = -EPERM;
	if (de->first)
		goto out1;

	err = -ENOTDIR;
	if (!de->directory)
		goto out1;

	hpfs_count_dnodes(dir->i_sb, hpfs_i(inode)->i_dno, NULL, NULL, &n_items);
	err = -ENOTEMPTY;
	if (n_items)
		goto out1;

	r = hpfs_remove_dirent(dir, dno, de, &qbh, 1);
	switch (r) {
	case 1:
		hpfs_error(dir->i_sb, "there was error when removing dirent");
		err = -EFSERROR;
		break;
	case 2:
		err = -ENOSPC;
		break;
	default:
		drop_nlink(dir);
		clear_nlink(inode);
		err = 0;
	}
	goto out;
out1:
	hpfs_brelse4(&qbh);
out:
	if (!err)
		hpfs_update_directory_times(dir);
	hpfs_unlock(dir->i_sb);
	return err;
}

static int hpfs_symlink_read_folio(struct file *file, struct folio *folio)
{
	struct page *page = &folio->page;
	char *link = page_address(page);
	struct inode *i = page->mapping->host;
	struct fnode *fnode;
	struct buffer_head *bh;
	int err;

	err = -EIO;
	hpfs_lock(i->i_sb);
	if (!(fnode = hpfs_map_fnode(i->i_sb, i->i_ino, &bh)))
		goto fail;
	err = hpfs_read_ea(i->i_sb, fnode, "SYMLINK", link, PAGE_SIZE);
	brelse(bh);
	if (err)
		goto fail;
	hpfs_unlock(i->i_sb);
	SetPageUptodate(page);
	unlock_page(page);
	return 0;

fail:
	hpfs_unlock(i->i_sb);
	SetPageError(page);
	unlock_page(page);
	return err;
}

const struct address_space_operations hpfs_symlink_aops = {
	.read_folio	= hpfs_symlink_read_folio
};

static int hpfs_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)
{
	const unsigned char *old_name = old_dentry->d_name.name;
	unsigned old_len = old_dentry->d_name.len;
	const unsigned char *new_name = new_dentry->d_name.name;
	unsigned new_len = new_dentry->d_name.len;
	struct inode *i = d_inode(old_dentry);
	struct inode *new_inode = d_inode(new_dentry);
	struct quad_buffer_head qbh, qbh1;
	struct hpfs_dirent *dep, *nde;
	struct hpfs_dirent de;
	dnode_secno dno;
	int r;
	struct buffer_head *bh;
	struct fnode *fnode;
	int err;

	if (flags & ~RENAME_NOREPLACE)
		return -EINVAL;

	if ((err = hpfs_chk_name(new_name, &new_len))) return err;
	err = 0;
	hpfs_adjust_length(old_name, &old_len);

	hpfs_lock(i->i_sb);
	/* order doesn't matter, due to VFS exclusion */
	
	/* Erm? Moving over the empty non-busy directory is perfectly legal */
	if (new_inode && S_ISDIR(new_inode->i_mode)) {
		err = -EINVAL;
		goto end1;
	}

	if (!(dep = map_dirent(old_dir, hpfs_i(old_dir)->i_dno, old_name, old_len, &dno, &qbh))) {
		hpfs_error(i->i_sb, "lookup succeeded but map dirent failed");
		err = -ENOENT;
		goto end1;
	}
	copy_de(&de, dep);
	de.hidden = new_name[0] == '.';

	if (new_inode) {
		int r;
		if ((r = hpfs_remove_dirent(old_dir, dno, dep, &qbh, 1)) != 2) {
			if ((nde = map_dirent(new_dir, hpfs_i(new_dir)->i_dno, new_name, new_len, NULL, &qbh1))) {
				clear_nlink(new_inode);
				copy_de(nde, &de);
				memcpy(nde->name, new_name, new_len);
				hpfs_mark_4buffers_dirty(&qbh1);
				hpfs_brelse4(&qbh1);
				goto end;
			}
			hpfs_error(new_dir->i_sb, "hpfs_rename: could not find dirent");
			err = -EFSERROR;
			goto end1;
		}
		err = -ENOSPC;
		goto end1;
	}

	if (new_dir == old_dir) hpfs_brelse4(&qbh);

	if ((r = hpfs_add_dirent(new_dir, new_name, new_len, &de))) {
		if (r == -1) hpfs_error(new_dir->i_sb, "hpfs_rename: dirent already exists!");
		err = r == 1 ? -ENOSPC : -EFSERROR;
		if (new_dir != old_dir) hpfs_brelse4(&qbh);
		goto end1;
	}
	
	if (new_dir == old_dir)
		if (!(dep = map_dirent(old_dir, hpfs_i(old_dir)->i_dno, old_name, old_len, &dno, &qbh))) {
			hpfs_error(i->i_sb, "lookup succeeded but map dirent failed at #2");
			err = -ENOENT;
			goto end1;
		}

	if ((r = hpfs_remove_dirent(old_dir, dno, dep, &qbh, 0))) {
		hpfs_error(i->i_sb, "hpfs_rename: could not remove dirent");
		err = r == 2 ? -ENOSPC : -EFSERROR;
		goto end1;
	}

end:
	hpfs_i(i)->i_parent_dir = new_dir->i_ino;
	if (S_ISDIR(i->i_mode)) {
		inc_nlink(new_dir);
		drop_nlink(old_dir);
	}
	if ((fnode = hpfs_map_fnode(i->i_sb, i->i_ino, &bh))) {
		fnode->up = cpu_to_le32(new_dir->i_ino);
		fnode->len = new_len;
		memcpy(fnode->name, new_name, new_len>15?15:new_len);
		if (new_len < 15) memset(&fnode->name[new_len], 0, 15 - new_len);
		mark_buffer_dirty(bh);
		brelse(bh);
	}
end1:
	if (!err) {
		hpfs_update_directory_times(old_dir);
		hpfs_update_directory_times(new_dir);
	}
	hpfs_unlock(i->i_sb);
	return err;
}

const struct inode_operations hpfs_dir_iops =
{
	.create		= hpfs_create,
	.lookup		= hpfs_lookup,
	.unlink		= hpfs_unlink,
	.symlink	= hpfs_symlink,
	.mkdir		= hpfs_mkdir,
	.rmdir		= hpfs_rmdir,
	.mknod		= hpfs_mknod,
	.rename		= hpfs_rename,
	.setattr	= hpfs_setattr,
};