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Commit fb1cc555 authored by Al Viro's avatar Al Viro
Browse files

gut do_filp_open() a bit more (do_last separation) 



Brute-force separation of stuff reachable from do_last: with
the exception of do_link:; just take all that crap to a helper
function as-is and have it tell the caller if it has to go
to do_link.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 648fa861

fs/namei.c

+103 −68
Original line number Diff line number Diff line
@@ -1645,6 +1645,104 @@ exit: 
	return ERR_PTR(error);

}



static struct file *do_last(struct nameidata *nd, struct path *path,

			    int open_flag, int flag, int acc_mode,

			    int mode, const char *pathname,

			    struct dentry *dir, int *is_link)

{

	struct file *filp;

	int error;



	*is_link = 0;



	error = PTR_ERR(path->dentry);

	if (IS_ERR(path->dentry)) {

		mutex_unlock(&dir->d_inode->i_mutex);

		goto exit;

	}



	if (IS_ERR(nd->intent.open.file)) {

		error = PTR_ERR(nd->intent.open.file);

		goto exit_mutex_unlock;

	}



	/* Negative dentry, just create the file */

	if (!path->dentry->d_inode) {

		/*

		 * This write is needed to ensure that a

		 * ro->rw transition does not occur between

		 * the time when the file is created and when

		 * a permanent write count is taken through

		 * the 'struct file' in nameidata_to_filp().

		 */

		error = mnt_want_write(nd->path.mnt);

		if (error)

			goto exit_mutex_unlock;

		error = __open_namei_create(nd, path, open_flag, mode);

		if (error) {

			mnt_drop_write(nd->path.mnt);

			goto exit;

		}

		filp = nameidata_to_filp(nd);

		mnt_drop_write(nd->path.mnt);

		if (nd->root.mnt)

			path_put(&nd->root);

		if (!IS_ERR(filp)) {

			error = ima_file_check(filp, acc_mode);

			if (error) {

				fput(filp);

				filp = ERR_PTR(error);

			}

		}

		return filp;

	}



	/*

	 * It already exists.

	 */

	mutex_unlock(&dir->d_inode->i_mutex);

	audit_inode(pathname, path->dentry);



	error = -EEXIST;

	if (flag & O_EXCL)

		goto exit_dput;



	if (__follow_mount(path)) {

		error = -ELOOP;

		if (flag & O_NOFOLLOW)

			goto exit_dput;

	}



	error = -ENOENT;

	if (!path->dentry->d_inode)

		goto exit_dput;

	if (path->dentry->d_inode->i_op->follow_link) {

		*is_link = 1;

		return NULL;

	}



	path_to_nameidata(path, nd);

	error = -EISDIR;

	if (S_ISDIR(path->dentry->d_inode->i_mode))

		goto exit;

	filp = finish_open(nd, open_flag, flag, acc_mode);

	if (nd->root.mnt)

		path_put(&nd->root);

	return filp;



exit_mutex_unlock:

	mutex_unlock(&dir->d_inode->i_mutex);

exit_dput:

	path_put_conditional(path, nd);

exit:

	if (!IS_ERR(nd->intent.open.file))

		release_open_intent(nd);

	if (nd->root.mnt)

		path_put(&nd->root);

	path_put(&nd->path);

	return ERR_PTR(error);

}



/*

 * Note that the low bits of the passed in "open_flag"

 * are not the same as in the local variable "flag". See
@@ -1661,6 +1759,7 @@ struct file *do_filp_open(int dfd, const char *pathname, 
	int count = 0;

	int flag = open_to_namei_flags(open_flag);

	int force_reval = 0;

	int is_link;



	/*

	 * O_SYNC is implemented as __O_SYNC|O_DSYNC.  As many places only
@@ -1754,82 +1853,18 @@ reval: 
	path.mnt = nd.path.mnt;



do_last:

	error = PTR_ERR(path.dentry);

	if (IS_ERR(path.dentry)) {

		mutex_unlock(&dir->d_inode->i_mutex);

		goto exit;

	}



	if (IS_ERR(nd.intent.open.file)) {

		error = PTR_ERR(nd.intent.open.file);

		goto exit_mutex_unlock;

	}



	/* Negative dentry, just create the file */

	if (!path.dentry->d_inode) {

		/*

		 * This write is needed to ensure that a

		 * ro->rw transition does not occur between

		 * the time when the file is created and when

		 * a permanent write count is taken through

		 * the 'struct file' in nameidata_to_filp().

		 */

		error = mnt_want_write(nd.path.mnt);

		if (error)

			goto exit_mutex_unlock;

		error = __open_namei_create(&nd, &path, open_flag, mode);

		if (error) {

			mnt_drop_write(nd.path.mnt);

			goto exit;

		}

		filp = nameidata_to_filp(&nd);

		mnt_drop_write(nd.path.mnt);

		if (nd.root.mnt)

			path_put(&nd.root);

		if (!IS_ERR(filp)) {

			error = ima_file_check(filp, acc_mode);

			if (error) {

				fput(filp);

				filp = ERR_PTR(error);

			}

		}

		return filp;

	}



	/*

	 * It already exists.

	 */

	mutex_unlock(&dir->d_inode->i_mutex);

	audit_inode(pathname, path.dentry);



	error = -EEXIST;

	if (flag & O_EXCL)

		goto exit_dput;



	if (__follow_mount(&path)) {

		error = -ELOOP;

		if (flag & O_NOFOLLOW)

			goto exit_dput;

	}



	error = -ENOENT;

	if (!path.dentry->d_inode)

		goto exit_dput;

	if (path.dentry->d_inode->i_op->follow_link)

	filp = do_last(&nd, &path, open_flag, flag, acc_mode, mode,

		       pathname, dir, &is_link);

	if (is_link)

		goto do_link;

	return filp;



	path_to_nameidata(&path, &nd);

	error = -EISDIR;

	if (S_ISDIR(path.dentry->d_inode->i_mode))

		goto exit;

ok:

	filp = finish_open(&nd, open_flag, flag, acc_mode);

	if (nd.root.mnt)

		path_put(&nd.root);

	return filp;



exit_mutex_unlock:

	mutex_unlock(&dir->d_inode->i_mutex);

exit_dput:

	path_put_conditional(&path, &nd);

exit: