linux/fs/hfs/dir.c
Christian Brauner 549c729771
fs: make helpers idmap mount aware
Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-01-24 14:27:20 +01:00

325 lines
8.0 KiB
C

/*
* 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,
};