1 files changed, 278 insertions, 0 deletions
diff --git a/fs/sysv/namei.c b/fs/sysv/namei.c
new file mode 100644
index 000000000..b2e6abc06
--- /dev/null
+++ b/fs/sysv/namei.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/sysv/namei.c
+ *
+ *  minix/namei.c
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  coh/namei.c
+ *  Copyright (C) 1993  Pascal Haible, Bruno Haible
+ *
+ *  sysv/namei.c
+ *  Copyright (C) 1993  Bruno Haible
+ *  Copyright (C) 1997, 1998  Krzysztof G. Baranowski
+ */
+
+#include <linux/pagemap.h>
+#include "sysv.h"
+
+static int add_nondir(struct dentry *dentry, struct inode *inode)
+{
+	int err = sysv_add_link(dentry, inode);
+	if (!err) {
+		d_instantiate(dentry, inode);
+		return 0;
+	}
+	inode_dec_link_count(inode);
+	iput(inode);
+	return err;
+}
+
+static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
+{
+	struct inode * inode = NULL;
+	ino_t ino;
+
+	if (dentry->d_name.len > SYSV_NAMELEN)
+		return ERR_PTR(-ENAMETOOLONG);
+	ino = sysv_inode_by_name(dentry);
+	if (ino)
+		inode = sysv_iget(dir->i_sb, ino);
+	return d_splice_alias(inode, dentry);
+}
+
+static int sysv_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+		      struct dentry *dentry, umode_t mode, dev_t rdev)
+{
+	struct inode * inode;
+	int err;
+
+	if (!old_valid_dev(rdev))
+		return -EINVAL;
+
+	inode = sysv_new_inode(dir, mode);
+	err = PTR_ERR(inode);
+
+	if (!IS_ERR(inode)) {
+		sysv_set_inode(inode, rdev);
+		mark_inode_dirty(inode);
+		err = add_nondir(dentry, inode);
+	}
+	return err;
+}
+
+static int sysv_create(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, umode_t mode, bool excl)
+{
+	return sysv_mknod(&init_user_ns, dir, dentry, mode, 0);
+}
+
+static int sysv_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+			struct dentry *dentry, const char *symname)
+{
+	int err = -ENAMETOOLONG;
+	int l = strlen(symname)+1;
+	struct inode * inode;
+
+	if (l > dir->i_sb->s_blocksize)
+		goto out;
+
+	inode = sysv_new_inode(dir, S_IFLNK|0777);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out;
+	
+	sysv_set_inode(inode, 0);
+	err = page_symlink(inode, symname, l);
+	if (err)
+		goto out_fail;
+
+	mark_inode_dirty(inode);
+	err = add_nondir(dentry, inode);
+out:
+	return err;
+
+out_fail:
+	inode_dec_link_count(inode);
+	iput(inode);
+	goto out;
+}
+
+static int sysv_link(struct dentry * old_dentry, struct inode * dir, 
+	struct dentry * dentry)
+{
+	struct inode *inode = d_inode(old_dentry);
+
+	inode->i_ctime = current_time(inode);
+	inode_inc_link_count(inode);
+	ihold(inode);
+
+	return add_nondir(dentry, inode);
+}
+
+static int sysv_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+		      struct dentry *dentry, umode_t mode)
+{
+	struct inode * inode;
+	int err;
+
+	inode_inc_link_count(dir);
+
+	inode = sysv_new_inode(dir, S_IFDIR|mode);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_dir;
+
+	sysv_set_inode(inode, 0);
+
+	inode_inc_link_count(inode);
+
+	err = sysv_make_empty(inode, dir);
+	if (err)
+		goto out_fail;
+
+	err = sysv_add_link(dentry, inode);
+	if (err)
+		goto out_fail;
+
+        d_instantiate(dentry, inode);
+out:
+	return err;
+
+out_fail:
+	inode_dec_link_count(inode);
+	inode_dec_link_count(inode);
+	iput(inode);
+out_dir:
+	inode_dec_link_count(dir);
+	goto out;
+}
+
+static int sysv_unlink(struct inode * dir, struct dentry * dentry)
+{
+	struct inode * inode = d_inode(dentry);
+	struct page * page;
+	struct sysv_dir_entry * de;
+	int err = -ENOENT;
+
+	de = sysv_find_entry(dentry, &page);
+	if (!de)
+		goto out;
+
+	err = sysv_delete_entry (de, page);
+	if (err)
+		goto out;
+
+	inode->i_ctime = dir->i_ctime;
+	inode_dec_link_count(inode);
+out:
+	return err;
+}
+
+static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
+{
+	struct inode *inode = d_inode(dentry);
+	int err = -ENOTEMPTY;
+
+	if (sysv_empty_dir(inode)) {
+		err = sysv_unlink(dir, dentry);
+		if (!err) {
+			inode->i_size = 0;
+			inode_dec_link_count(inode);
+			inode_dec_link_count(dir);
+		}
+	}
+	return err;
+}
+
+/*
+ * Anybody can rename anything with this: the permission checks are left to the
+ * higher-level routines.
+ */
+static int sysv_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)
+{
+	struct inode * old_inode = d_inode(old_dentry);
+	struct inode * new_inode = d_inode(new_dentry);
+	struct page * dir_page = NULL;
+	struct sysv_dir_entry * dir_de = NULL;
+	struct page * old_page;
+	struct sysv_dir_entry * old_de;
+	int err = -ENOENT;
+
+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+
+	old_de = sysv_find_entry(old_dentry, &old_page);
+	if (!old_de)
+		goto out;
+
+	if (S_ISDIR(old_inode->i_mode)) {
+		err = -EIO;
+		dir_de = sysv_dotdot(old_inode, &dir_page);
+		if (!dir_de)
+			goto out_old;
+	}
+
+	if (new_inode) {
+		struct page * new_page;
+		struct sysv_dir_entry * new_de;
+
+		err = -ENOTEMPTY;
+		if (dir_de && !sysv_empty_dir(new_inode))
+			goto out_dir;
+
+		err = -ENOENT;
+		new_de = sysv_find_entry(new_dentry, &new_page);
+		if (!new_de)
+			goto out_dir;
+		sysv_set_link(new_de, new_page, old_inode);
+		new_inode->i_ctime = current_time(new_inode);
+		if (dir_de)
+			drop_nlink(new_inode);
+		inode_dec_link_count(new_inode);
+	} else {
+		err = sysv_add_link(new_dentry, old_inode);
+		if (err)
+			goto out_dir;
+		if (dir_de)
+			inode_inc_link_count(new_dir);
+	}
+
+	sysv_delete_entry(old_de, old_page);
+	mark_inode_dirty(old_inode);
+
+	if (dir_de) {
+		sysv_set_link(dir_de, dir_page, new_dir);
+		inode_dec_link_count(old_dir);
+	}
+	return 0;
+
+out_dir:
+	if (dir_de) {
+		kunmap(dir_page);
+		put_page(dir_page);
+	}
+out_old:
+	kunmap(old_page);
+	put_page(old_page);
+out:
+	return err;
+}
+
+/*
+ * directories can handle most operations...
+ */
+const struct inode_operations sysv_dir_inode_operations = {
+	.create		= sysv_create,
+	.lookup		= sysv_lookup,
+	.link		= sysv_link,
+	.unlink		= sysv_unlink,
+	.symlink	= sysv_symlink,
+	.mkdir		= sysv_mkdir,
+	.rmdir		= sysv_rmdir,
+	.mknod		= sysv_mknod,
+	.rename		= sysv_rename,
+	.getattr	= sysv_getattr,
+};