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Commit 2ad94ae6 authored by Al Viro's avatar Al Viro
Browse files

[PATCH] new (local) helper: user_path_parent() 



Preparation to untangling intents mess: reduce the number of do_path_lookup()
callers.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 2d8f3038

fs/namei.c

+57 −80
Original line number Diff line number Diff line
@@ -1352,6 +1352,24 @@ int user_path_at(int dfd, const char __user *name, unsigned flags, 
	return err;

}



static int user_path_parent(int dfd, const char __user *path,

			struct nameidata *nd, char **name)

{

	char *s = getname(path);

	int error;



	if (IS_ERR(s))

		return PTR_ERR(s);



	error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd);

	if (error)

		putname(s);

	else

		*name = s;



	return error;

}



/*

 * It's inline, so penalty for filesystems that don't use sticky bit is

 * minimal.
@@ -1989,20 +2007,18 @@ static int may_mknod(mode_t mode) 
asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode,

				unsigned dev)

{

	int error = 0;

	int error;

	char *tmp;

	struct dentry *dentry;

	struct nameidata nd;



	if (S_ISDIR(mode))

		return -EPERM;

	tmp = getname(filename);

	if (IS_ERR(tmp))

		return PTR_ERR(tmp);



	error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd);

	error = user_path_parent(dfd, filename, &nd, &tmp);

	if (error)

		goto out;

		return error;



	dentry = lookup_create(&nd, 0);

	if (IS_ERR(dentry)) {

		error = PTR_ERR(dentry);
@@ -2034,7 +2050,6 @@ asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, 
out_unlock:

	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

	path_put(&nd.path);

out:

	putname(tmp);



	return error;
@@ -2074,14 +2089,10 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode) 
	struct dentry *dentry;

	struct nameidata nd;



	tmp = getname(pathname);

	error = PTR_ERR(tmp);

	if (IS_ERR(tmp))

	error = user_path_parent(dfd, pathname, &nd, &tmp);

	if (error)

		goto out_err;



	error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd);

	if (error)

		goto out;

	dentry = lookup_create(&nd, 1);

	error = PTR_ERR(dentry);

	if (IS_ERR(dentry))
@@ -2099,7 +2110,6 @@ asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode) 
out_unlock:

	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

	path_put(&nd.path);

out:

	putname(tmp);

out_err:

	return error;
@@ -2177,13 +2187,9 @@ static long do_rmdir(int dfd, const char __user *pathname) 
	struct dentry *dentry;

	struct nameidata nd;



	name = getname(pathname);

	if(IS_ERR(name))

		return PTR_ERR(name);



	error = do_path_lookup(dfd, name, LOOKUP_PARENT, &nd);

	error = user_path_parent(dfd, pathname, &nd, &name);

	if (error)

		goto exit;

		return error;



	switch(nd.last_type) {

		case LAST_DOTDOT:
@@ -2212,7 +2218,6 @@ static long do_rmdir(int dfd, const char __user *pathname) 
	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

exit1:

	path_put(&nd.path);

exit:

	putname(name);

	return error;

}
@@ -2261,19 +2266,16 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry) 
 */

static long do_unlinkat(int dfd, const char __user *pathname)

{

	int error = 0;

	int error;

	char *name;

	struct dentry *dentry;

	struct nameidata nd;

	struct inode *inode = NULL;



	name = getname(pathname);

	if(IS_ERR(name))

		return PTR_ERR(name);



	error = do_path_lookup(dfd, name, LOOKUP_PARENT, &nd);

	error = user_path_parent(dfd, pathname, &nd, &name);

	if (error)

		goto exit;

		return error;



	error = -EISDIR;

	if (nd.last_type != LAST_NORM)

		goto exit1;
@@ -2300,7 +2302,6 @@ static long do_unlinkat(int dfd, const char __user *pathname) 
		iput(inode);	/* truncate the inode here */

exit1:

	path_put(&nd.path);

exit:

	putname(name);

	return error;
@@ -2350,7 +2351,7 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) 
asmlinkage long sys_symlinkat(const char __user *oldname,

			      int newdfd, const char __user *newname)

{

	int error = 0;

	int error;

	char *from;

	char *to;

	struct dentry *dentry;
@@ -2359,14 +2360,11 @@ asmlinkage long sys_symlinkat(const char __user *oldname, 
	from = getname(oldname);

	if (IS_ERR(from))

		return PTR_ERR(from);

	to = getname(newname);

	error = PTR_ERR(to);

	if (IS_ERR(to))

		goto out_putname;



	error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd);

	error = user_path_parent(newdfd, newname, &nd, &to);

	if (error)

		goto out;

		goto out_putname;



	dentry = lookup_create(&nd, 0);

	error = PTR_ERR(dentry);

	if (IS_ERR(dentry))
@@ -2382,7 +2380,6 @@ asmlinkage long sys_symlinkat(const char __user *oldname, 
out_unlock:

	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

	path_put(&nd.path);

out:

	putname(to);

out_putname:

	putname(from);
@@ -2454,16 +2451,13 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname, 
	if ((flags & ~AT_SYMLINK_FOLLOW) != 0)

		return -EINVAL;



	to = getname(newname);

	if (IS_ERR(to))

		return PTR_ERR(to);



	error = user_path_at(olddfd, oldname,

			     flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0,

			     &old_path);

	if (error)

		goto exit;

	error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd);

		return error;



	error = user_path_parent(newdfd, newname, &nd, &to);

	if (error)

		goto out;

	error = -EXDEV;
@@ -2484,10 +2478,9 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname, 
	mutex_unlock(&nd.path.dentry->d_inode->i_mutex);

out_release:

	path_put(&nd.path);

	putname(to);

out:

	path_put(&old_path);

exit:

	putname(to);



	return error;

}
@@ -2643,20 +2636,22 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, 
	return error;

}



static int do_rename(int olddfd, const char *oldname,

			int newdfd, const char *newname)

asmlinkage long sys_renameat(int olddfd, const char __user *oldname,

			     int newdfd, const char __user *newname)

{

	int error = 0;

	struct dentry *old_dir, *new_dir;

	struct dentry *old_dentry, *new_dentry;

	struct dentry *trap;

	struct nameidata oldnd, newnd;

	char *from;

	char *to;

	int error;



	error = do_path_lookup(olddfd, oldname, LOOKUP_PARENT, &oldnd);

	error = user_path_parent(olddfd, oldname, &oldnd, &from);

	if (error)

		goto exit;



	error = do_path_lookup(newdfd, newname, LOOKUP_PARENT, &newnd);

	error = user_path_parent(newdfd, newname, &newnd, &to);

	if (error)

		goto exit1;
@@ -2718,29 +2713,11 @@ static int do_rename(int olddfd, const char *oldname, 
	unlock_rename(new_dir, old_dir);

exit2:

	path_put(&newnd.path);

	putname(to);

exit1:

	path_put(&oldnd.path);

exit:

	return error;

}



asmlinkage long sys_renameat(int olddfd, const char __user *oldname,

			     int newdfd, const char __user *newname)

{

	int error;

	char * from;

	char * to;



	from = getname(oldname);

	if(IS_ERR(from))

		return PTR_ERR(from);

	to = getname(newname);

	error = PTR_ERR(to);

	if (!IS_ERR(to)) {

		error = do_rename(olddfd, from, newdfd, to);

		putname(to);

	}

	putname(from);

exit:

	return error;

}