1  // SPDX-License-Identifier: GPL-2.0-only
2  /*
3   * net/sunrpc/rpc_pipe.c
4   *
5   * Userland/kernel interface for rpcauth_gss.
6   * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
7   * and fs/sysfs/inode.c
8   *
9   * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
10   *
11   */
12  #include <linux/module.h>
13  #include <linux/slab.h>
14  #include <linux/string.h>
15  #include <linux/pagemap.h>
16  #include <linux/mount.h>
17  #include <linux/fs_context.h>
18  #include <linux/namei.h>
19  #include <linux/fsnotify.h>
20  #include <linux/kernel.h>
21  #include <linux/rcupdate.h>
22  #include <linux/utsname.h>
23  
24  #include <asm/ioctls.h>
25  #include <linux/poll.h>
26  #include <linux/wait.h>
27  #include <linux/seq_file.h>
28  
29  #include <linux/sunrpc/clnt.h>
30  #include <linux/workqueue.h>
31  #include <linux/sunrpc/rpc_pipe_fs.h>
32  #include <linux/sunrpc/cache.h>
33  #include <linux/nsproxy.h>
34  #include <linux/notifier.h>
35  
36  #include "netns.h"
37  #include "sunrpc.h"
38  
39  #define RPCDBG_FACILITY RPCDBG_DEBUG
40  
41  #define NET_NAME(net)	((net == &init_net) ? " (init_net)" : "")
42  
43  static struct file_system_type rpc_pipe_fs_type;
44  static const struct rpc_pipe_ops gssd_dummy_pipe_ops;
45  
46  static struct kmem_cache *rpc_inode_cachep __read_mostly;
47  
48  #define RPC_UPCALL_TIMEOUT (30*HZ)
49  
50  static BLOCKING_NOTIFIER_HEAD(rpc_pipefs_notifier_list);
51  
rpc_pipefs_notifier_register(struct notifier_block * nb)52  int rpc_pipefs_notifier_register(struct notifier_block *nb)
53  {
54  	return blocking_notifier_chain_register(&rpc_pipefs_notifier_list, nb);
55  }
56  EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_register);
57  
rpc_pipefs_notifier_unregister(struct notifier_block * nb)58  void rpc_pipefs_notifier_unregister(struct notifier_block *nb)
59  {
60  	blocking_notifier_chain_unregister(&rpc_pipefs_notifier_list, nb);
61  }
62  EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_unregister);
63  
rpc_purge_list(wait_queue_head_t * waitq,struct list_head * head,void (* destroy_msg)(struct rpc_pipe_msg *),int err)64  static void rpc_purge_list(wait_queue_head_t *waitq, struct list_head *head,
65  		void (*destroy_msg)(struct rpc_pipe_msg *), int err)
66  {
67  	struct rpc_pipe_msg *msg;
68  
69  	if (list_empty(head))
70  		return;
71  	do {
72  		msg = list_entry(head->next, struct rpc_pipe_msg, list);
73  		list_del_init(&msg->list);
74  		msg->errno = err;
75  		destroy_msg(msg);
76  	} while (!list_empty(head));
77  
78  	if (waitq)
79  		wake_up(waitq);
80  }
81  
82  static void
rpc_timeout_upcall_queue(struct work_struct * work)83  rpc_timeout_upcall_queue(struct work_struct *work)
84  {
85  	LIST_HEAD(free_list);
86  	struct rpc_pipe *pipe =
87  		container_of(work, struct rpc_pipe, queue_timeout.work);
88  	void (*destroy_msg)(struct rpc_pipe_msg *);
89  	struct dentry *dentry;
90  
91  	spin_lock(&pipe->lock);
92  	destroy_msg = pipe->ops->destroy_msg;
93  	if (pipe->nreaders == 0) {
94  		list_splice_init(&pipe->pipe, &free_list);
95  		pipe->pipelen = 0;
96  	}
97  	dentry = dget(pipe->dentry);
98  	spin_unlock(&pipe->lock);
99  	rpc_purge_list(dentry ? &RPC_I(d_inode(dentry))->waitq : NULL,
100  			&free_list, destroy_msg, -ETIMEDOUT);
101  	dput(dentry);
102  }
103  
rpc_pipe_generic_upcall(struct file * filp,struct rpc_pipe_msg * msg,char __user * dst,size_t buflen)104  ssize_t rpc_pipe_generic_upcall(struct file *filp, struct rpc_pipe_msg *msg,
105  				char __user *dst, size_t buflen)
106  {
107  	char *data = (char *)msg->data + msg->copied;
108  	size_t mlen = min(msg->len - msg->copied, buflen);
109  	unsigned long left;
110  
111  	left = copy_to_user(dst, data, mlen);
112  	if (left == mlen) {
113  		msg->errno = -EFAULT;
114  		return -EFAULT;
115  	}
116  
117  	mlen -= left;
118  	msg->copied += mlen;
119  	msg->errno = 0;
120  	return mlen;
121  }
122  EXPORT_SYMBOL_GPL(rpc_pipe_generic_upcall);
123  
124  /**
125   * rpc_queue_upcall - queue an upcall message to userspace
126   * @pipe: upcall pipe on which to queue given message
127   * @msg: message to queue
128   *
129   * Call with an @inode created by rpc_mkpipe() to queue an upcall.
130   * A userspace process may then later read the upcall by performing a
131   * read on an open file for this inode.  It is up to the caller to
132   * initialize the fields of @msg (other than @msg->list) appropriately.
133   */
134  int
rpc_queue_upcall(struct rpc_pipe * pipe,struct rpc_pipe_msg * msg)135  rpc_queue_upcall(struct rpc_pipe *pipe, struct rpc_pipe_msg *msg)
136  {
137  	int res = -EPIPE;
138  	struct dentry *dentry;
139  
140  	spin_lock(&pipe->lock);
141  	if (pipe->nreaders) {
142  		list_add_tail(&msg->list, &pipe->pipe);
143  		pipe->pipelen += msg->len;
144  		res = 0;
145  	} else if (pipe->flags & RPC_PIPE_WAIT_FOR_OPEN) {
146  		if (list_empty(&pipe->pipe))
147  			queue_delayed_work(rpciod_workqueue,
148  					&pipe->queue_timeout,
149  					RPC_UPCALL_TIMEOUT);
150  		list_add_tail(&msg->list, &pipe->pipe);
151  		pipe->pipelen += msg->len;
152  		res = 0;
153  	}
154  	dentry = dget(pipe->dentry);
155  	spin_unlock(&pipe->lock);
156  	if (dentry) {
157  		wake_up(&RPC_I(d_inode(dentry))->waitq);
158  		dput(dentry);
159  	}
160  	return res;
161  }
162  EXPORT_SYMBOL_GPL(rpc_queue_upcall);
163  
164  static inline void
rpc_inode_setowner(struct inode * inode,void * private)165  rpc_inode_setowner(struct inode *inode, void *private)
166  {
167  	RPC_I(inode)->private = private;
168  }
169  
170  static void
rpc_close_pipes(struct inode * inode)171  rpc_close_pipes(struct inode *inode)
172  {
173  	struct rpc_pipe *pipe = RPC_I(inode)->pipe;
174  	int need_release;
175  	LIST_HEAD(free_list);
176  
177  	inode_lock(inode);
178  	spin_lock(&pipe->lock);
179  	need_release = pipe->nreaders != 0 || pipe->nwriters != 0;
180  	pipe->nreaders = 0;
181  	list_splice_init(&pipe->in_upcall, &free_list);
182  	list_splice_init(&pipe->pipe, &free_list);
183  	pipe->pipelen = 0;
184  	pipe->dentry = NULL;
185  	spin_unlock(&pipe->lock);
186  	rpc_purge_list(&RPC_I(inode)->waitq, &free_list, pipe->ops->destroy_msg, -EPIPE);
187  	pipe->nwriters = 0;
188  	if (need_release && pipe->ops->release_pipe)
189  		pipe->ops->release_pipe(inode);
190  	cancel_delayed_work_sync(&pipe->queue_timeout);
191  	rpc_inode_setowner(inode, NULL);
192  	RPC_I(inode)->pipe = NULL;
193  	inode_unlock(inode);
194  }
195  
196  static struct inode *
rpc_alloc_inode(struct super_block * sb)197  rpc_alloc_inode(struct super_block *sb)
198  {
199  	struct rpc_inode *rpci;
200  	rpci = alloc_inode_sb(sb, rpc_inode_cachep, GFP_KERNEL);
201  	if (!rpci)
202  		return NULL;
203  	return &rpci->vfs_inode;
204  }
205  
206  static void
rpc_free_inode(struct inode * inode)207  rpc_free_inode(struct inode *inode)
208  {
209  	kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
210  }
211  
212  static int
rpc_pipe_open(struct inode * inode,struct file * filp)213  rpc_pipe_open(struct inode *inode, struct file *filp)
214  {
215  	struct rpc_pipe *pipe;
216  	int first_open;
217  	int res = -ENXIO;
218  
219  	inode_lock(inode);
220  	pipe = RPC_I(inode)->pipe;
221  	if (pipe == NULL)
222  		goto out;
223  	first_open = pipe->nreaders == 0 && pipe->nwriters == 0;
224  	if (first_open && pipe->ops->open_pipe) {
225  		res = pipe->ops->open_pipe(inode);
226  		if (res)
227  			goto out;
228  	}
229  	if (filp->f_mode & FMODE_READ)
230  		pipe->nreaders++;
231  	if (filp->f_mode & FMODE_WRITE)
232  		pipe->nwriters++;
233  	res = 0;
234  out:
235  	inode_unlock(inode);
236  	return res;
237  }
238  
239  static int
rpc_pipe_release(struct inode * inode,struct file * filp)240  rpc_pipe_release(struct inode *inode, struct file *filp)
241  {
242  	struct rpc_pipe *pipe;
243  	struct rpc_pipe_msg *msg;
244  	int last_close;
245  
246  	inode_lock(inode);
247  	pipe = RPC_I(inode)->pipe;
248  	if (pipe == NULL)
249  		goto out;
250  	msg = filp->private_data;
251  	if (msg != NULL) {
252  		spin_lock(&pipe->lock);
253  		msg->errno = -EAGAIN;
254  		list_del_init(&msg->list);
255  		spin_unlock(&pipe->lock);
256  		pipe->ops->destroy_msg(msg);
257  	}
258  	if (filp->f_mode & FMODE_WRITE)
259  		pipe->nwriters --;
260  	if (filp->f_mode & FMODE_READ) {
261  		pipe->nreaders --;
262  		if (pipe->nreaders == 0) {
263  			LIST_HEAD(free_list);
264  			spin_lock(&pipe->lock);
265  			list_splice_init(&pipe->pipe, &free_list);
266  			pipe->pipelen = 0;
267  			spin_unlock(&pipe->lock);
268  			rpc_purge_list(&RPC_I(inode)->waitq, &free_list,
269  					pipe->ops->destroy_msg, -EAGAIN);
270  		}
271  	}
272  	last_close = pipe->nwriters == 0 && pipe->nreaders == 0;
273  	if (last_close && pipe->ops->release_pipe)
274  		pipe->ops->release_pipe(inode);
275  out:
276  	inode_unlock(inode);
277  	return 0;
278  }
279  
280  static ssize_t
rpc_pipe_read(struct file * filp,char __user * buf,size_t len,loff_t * offset)281  rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
282  {
283  	struct inode *inode = file_inode(filp);
284  	struct rpc_pipe *pipe;
285  	struct rpc_pipe_msg *msg;
286  	int res = 0;
287  
288  	inode_lock(inode);
289  	pipe = RPC_I(inode)->pipe;
290  	if (pipe == NULL) {
291  		res = -EPIPE;
292  		goto out_unlock;
293  	}
294  	msg = filp->private_data;
295  	if (msg == NULL) {
296  		spin_lock(&pipe->lock);
297  		if (!list_empty(&pipe->pipe)) {
298  			msg = list_entry(pipe->pipe.next,
299  					struct rpc_pipe_msg,
300  					list);
301  			list_move(&msg->list, &pipe->in_upcall);
302  			pipe->pipelen -= msg->len;
303  			filp->private_data = msg;
304  			msg->copied = 0;
305  		}
306  		spin_unlock(&pipe->lock);
307  		if (msg == NULL)
308  			goto out_unlock;
309  	}
310  	/* NOTE: it is up to the callback to update msg->copied */
311  	res = pipe->ops->upcall(filp, msg, buf, len);
312  	if (res < 0 || msg->len == msg->copied) {
313  		filp->private_data = NULL;
314  		spin_lock(&pipe->lock);
315  		list_del_init(&msg->list);
316  		spin_unlock(&pipe->lock);
317  		pipe->ops->destroy_msg(msg);
318  	}
319  out_unlock:
320  	inode_unlock(inode);
321  	return res;
322  }
323  
324  static ssize_t
rpc_pipe_write(struct file * filp,const char __user * buf,size_t len,loff_t * offset)325  rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
326  {
327  	struct inode *inode = file_inode(filp);
328  	int res;
329  
330  	inode_lock(inode);
331  	res = -EPIPE;
332  	if (RPC_I(inode)->pipe != NULL)
333  		res = RPC_I(inode)->pipe->ops->downcall(filp, buf, len);
334  	inode_unlock(inode);
335  	return res;
336  }
337  
338  static __poll_t
rpc_pipe_poll(struct file * filp,struct poll_table_struct * wait)339  rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
340  {
341  	struct inode *inode = file_inode(filp);
342  	struct rpc_inode *rpci = RPC_I(inode);
343  	__poll_t mask = EPOLLOUT | EPOLLWRNORM;
344  
345  	poll_wait(filp, &rpci->waitq, wait);
346  
347  	inode_lock(inode);
348  	if (rpci->pipe == NULL)
349  		mask |= EPOLLERR | EPOLLHUP;
350  	else if (filp->private_data || !list_empty(&rpci->pipe->pipe))
351  		mask |= EPOLLIN | EPOLLRDNORM;
352  	inode_unlock(inode);
353  	return mask;
354  }
355  
356  static long
rpc_pipe_ioctl(struct file * filp,unsigned int cmd,unsigned long arg)357  rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
358  {
359  	struct inode *inode = file_inode(filp);
360  	struct rpc_pipe *pipe;
361  	int len;
362  
363  	switch (cmd) {
364  	case FIONREAD:
365  		inode_lock(inode);
366  		pipe = RPC_I(inode)->pipe;
367  		if (pipe == NULL) {
368  			inode_unlock(inode);
369  			return -EPIPE;
370  		}
371  		spin_lock(&pipe->lock);
372  		len = pipe->pipelen;
373  		if (filp->private_data) {
374  			struct rpc_pipe_msg *msg;
375  			msg = filp->private_data;
376  			len += msg->len - msg->copied;
377  		}
378  		spin_unlock(&pipe->lock);
379  		inode_unlock(inode);
380  		return put_user(len, (int __user *)arg);
381  	default:
382  		return -EINVAL;
383  	}
384  }
385  
386  static const struct file_operations rpc_pipe_fops = {
387  	.owner		= THIS_MODULE,
388  	.read		= rpc_pipe_read,
389  	.write		= rpc_pipe_write,
390  	.poll		= rpc_pipe_poll,
391  	.unlocked_ioctl	= rpc_pipe_ioctl,
392  	.open		= rpc_pipe_open,
393  	.release	= rpc_pipe_release,
394  };
395  
396  static int
rpc_show_info(struct seq_file * m,void * v)397  rpc_show_info(struct seq_file *m, void *v)
398  {
399  	struct rpc_clnt *clnt = m->private;
400  
401  	rcu_read_lock();
402  	seq_printf(m, "RPC server: %s\n",
403  			rcu_dereference(clnt->cl_xprt)->servername);
404  	seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_program->name,
405  			clnt->cl_prog, clnt->cl_vers);
406  	seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
407  	seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
408  	seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
409  	rcu_read_unlock();
410  	return 0;
411  }
412  
413  static int
rpc_info_open(struct inode * inode,struct file * file)414  rpc_info_open(struct inode *inode, struct file *file)
415  {
416  	struct rpc_clnt *clnt = NULL;
417  	int ret = single_open(file, rpc_show_info, NULL);
418  
419  	if (!ret) {
420  		struct seq_file *m = file->private_data;
421  
422  		spin_lock(&file->f_path.dentry->d_lock);
423  		if (!d_unhashed(file->f_path.dentry))
424  			clnt = RPC_I(inode)->private;
425  		if (clnt != NULL && refcount_inc_not_zero(&clnt->cl_count)) {
426  			spin_unlock(&file->f_path.dentry->d_lock);
427  			m->private = clnt;
428  		} else {
429  			spin_unlock(&file->f_path.dentry->d_lock);
430  			single_release(inode, file);
431  			ret = -EINVAL;
432  		}
433  	}
434  	return ret;
435  }
436  
437  static int
rpc_info_release(struct inode * inode,struct file * file)438  rpc_info_release(struct inode *inode, struct file *file)
439  {
440  	struct seq_file *m = file->private_data;
441  	struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
442  
443  	if (clnt)
444  		rpc_release_client(clnt);
445  	return single_release(inode, file);
446  }
447  
448  static const struct file_operations rpc_info_operations = {
449  	.owner		= THIS_MODULE,
450  	.open		= rpc_info_open,
451  	.read		= seq_read,
452  	.llseek		= seq_lseek,
453  	.release	= rpc_info_release,
454  };
455  
456  
457  /*
458   * Description of fs contents.
459   */
460  struct rpc_filelist {
461  	const char *name;
462  	const struct file_operations *i_fop;
463  	umode_t mode;
464  };
465  
466  static struct inode *
rpc_get_inode(struct super_block * sb,umode_t mode)467  rpc_get_inode(struct super_block *sb, umode_t mode)
468  {
469  	struct inode *inode = new_inode(sb);
470  	if (!inode)
471  		return NULL;
472  	inode->i_ino = get_next_ino();
473  	inode->i_mode = mode;
474  	simple_inode_init_ts(inode);
475  	switch (mode & S_IFMT) {
476  	case S_IFDIR:
477  		inode->i_fop = &simple_dir_operations;
478  		inode->i_op = &simple_dir_inode_operations;
479  		inc_nlink(inode);
480  		break;
481  	default:
482  		break;
483  	}
484  	return inode;
485  }
486  
__rpc_create_common(struct inode * dir,struct dentry * dentry,umode_t mode,const struct file_operations * i_fop,void * private)487  static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
488  			       umode_t mode,
489  			       const struct file_operations *i_fop,
490  			       void *private)
491  {
492  	struct inode *inode;
493  
494  	d_drop(dentry);
495  	inode = rpc_get_inode(dir->i_sb, mode);
496  	if (!inode)
497  		goto out_err;
498  	inode->i_ino = iunique(dir->i_sb, 100);
499  	if (i_fop)
500  		inode->i_fop = i_fop;
501  	if (private)
502  		rpc_inode_setowner(inode, private);
503  	d_add(dentry, inode);
504  	return 0;
505  out_err:
506  	printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %pd\n",
507  			__FILE__, __func__, dentry);
508  	dput(dentry);
509  	return -ENOMEM;
510  }
511  
__rpc_create(struct inode * dir,struct dentry * dentry,umode_t mode,const struct file_operations * i_fop,void * private)512  static int __rpc_create(struct inode *dir, struct dentry *dentry,
513  			umode_t mode,
514  			const struct file_operations *i_fop,
515  			void *private)
516  {
517  	int err;
518  
519  	err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
520  	if (err)
521  		return err;
522  	fsnotify_create(dir, dentry);
523  	return 0;
524  }
525  
__rpc_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode,const struct file_operations * i_fop,void * private)526  static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
527  		       umode_t mode,
528  		       const struct file_operations *i_fop,
529  		       void *private)
530  {
531  	int err;
532  
533  	err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
534  	if (err)
535  		return err;
536  	inc_nlink(dir);
537  	fsnotify_mkdir(dir, dentry);
538  	return 0;
539  }
540  
541  static void
init_pipe(struct rpc_pipe * pipe)542  init_pipe(struct rpc_pipe *pipe)
543  {
544  	pipe->nreaders = 0;
545  	pipe->nwriters = 0;
546  	INIT_LIST_HEAD(&pipe->in_upcall);
547  	INIT_LIST_HEAD(&pipe->in_downcall);
548  	INIT_LIST_HEAD(&pipe->pipe);
549  	pipe->pipelen = 0;
550  	INIT_DELAYED_WORK(&pipe->queue_timeout,
551  			    rpc_timeout_upcall_queue);
552  	pipe->ops = NULL;
553  	spin_lock_init(&pipe->lock);
554  	pipe->dentry = NULL;
555  }
556  
rpc_destroy_pipe_data(struct rpc_pipe * pipe)557  void rpc_destroy_pipe_data(struct rpc_pipe *pipe)
558  {
559  	kfree(pipe);
560  }
561  EXPORT_SYMBOL_GPL(rpc_destroy_pipe_data);
562  
rpc_mkpipe_data(const struct rpc_pipe_ops * ops,int flags)563  struct rpc_pipe *rpc_mkpipe_data(const struct rpc_pipe_ops *ops, int flags)
564  {
565  	struct rpc_pipe *pipe;
566  
567  	pipe = kzalloc(sizeof(struct rpc_pipe), GFP_KERNEL);
568  	if (!pipe)
569  		return ERR_PTR(-ENOMEM);
570  	init_pipe(pipe);
571  	pipe->ops = ops;
572  	pipe->flags = flags;
573  	return pipe;
574  }
575  EXPORT_SYMBOL_GPL(rpc_mkpipe_data);
576  
__rpc_mkpipe_dentry(struct inode * dir,struct dentry * dentry,umode_t mode,const struct file_operations * i_fop,void * private,struct rpc_pipe * pipe)577  static int __rpc_mkpipe_dentry(struct inode *dir, struct dentry *dentry,
578  			       umode_t mode,
579  			       const struct file_operations *i_fop,
580  			       void *private,
581  			       struct rpc_pipe *pipe)
582  {
583  	struct rpc_inode *rpci;
584  	int err;
585  
586  	err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
587  	if (err)
588  		return err;
589  	rpci = RPC_I(d_inode(dentry));
590  	rpci->private = private;
591  	rpci->pipe = pipe;
592  	fsnotify_create(dir, dentry);
593  	return 0;
594  }
595  
__rpc_rmdir(struct inode * dir,struct dentry * dentry)596  static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
597  {
598  	int ret;
599  
600  	dget(dentry);
601  	ret = simple_rmdir(dir, dentry);
602  	d_drop(dentry);
603  	if (!ret)
604  		fsnotify_rmdir(dir, dentry);
605  	dput(dentry);
606  	return ret;
607  }
608  
__rpc_unlink(struct inode * dir,struct dentry * dentry)609  static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
610  {
611  	int ret;
612  
613  	dget(dentry);
614  	ret = simple_unlink(dir, dentry);
615  	d_drop(dentry);
616  	if (!ret)
617  		fsnotify_unlink(dir, dentry);
618  	dput(dentry);
619  	return ret;
620  }
621  
__rpc_rmpipe(struct inode * dir,struct dentry * dentry)622  static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
623  {
624  	struct inode *inode = d_inode(dentry);
625  
626  	rpc_close_pipes(inode);
627  	return __rpc_unlink(dir, dentry);
628  }
629  
__rpc_lookup_create_exclusive(struct dentry * parent,const char * name)630  static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
631  					  const char *name)
632  {
633  	struct qstr q = QSTR_INIT(name, strlen(name));
634  	struct dentry *dentry = d_hash_and_lookup(parent, &q);
635  	if (!dentry) {
636  		dentry = d_alloc(parent, &q);
637  		if (!dentry)
638  			return ERR_PTR(-ENOMEM);
639  	}
640  	if (d_really_is_negative(dentry))
641  		return dentry;
642  	dput(dentry);
643  	return ERR_PTR(-EEXIST);
644  }
645  
646  /*
647   * FIXME: This probably has races.
648   */
__rpc_depopulate(struct dentry * parent,const struct rpc_filelist * files,int start,int eof)649  static void __rpc_depopulate(struct dentry *parent,
650  			     const struct rpc_filelist *files,
651  			     int start, int eof)
652  {
653  	struct inode *dir = d_inode(parent);
654  	struct dentry *dentry;
655  	struct qstr name;
656  	int i;
657  
658  	for (i = start; i < eof; i++) {
659  		name.name = files[i].name;
660  		name.len = strlen(files[i].name);
661  		dentry = d_hash_and_lookup(parent, &name);
662  
663  		if (dentry == NULL)
664  			continue;
665  		if (d_really_is_negative(dentry))
666  			goto next;
667  		switch (d_inode(dentry)->i_mode & S_IFMT) {
668  			default:
669  				BUG();
670  			case S_IFREG:
671  				__rpc_unlink(dir, dentry);
672  				break;
673  			case S_IFDIR:
674  				__rpc_rmdir(dir, dentry);
675  		}
676  next:
677  		dput(dentry);
678  	}
679  }
680  
rpc_depopulate(struct dentry * parent,const struct rpc_filelist * files,int start,int eof)681  static void rpc_depopulate(struct dentry *parent,
682  			   const struct rpc_filelist *files,
683  			   int start, int eof)
684  {
685  	struct inode *dir = d_inode(parent);
686  
687  	inode_lock_nested(dir, I_MUTEX_CHILD);
688  	__rpc_depopulate(parent, files, start, eof);
689  	inode_unlock(dir);
690  }
691  
rpc_populate(struct dentry * parent,const struct rpc_filelist * files,int start,int eof,void * private)692  static int rpc_populate(struct dentry *parent,
693  			const struct rpc_filelist *files,
694  			int start, int eof,
695  			void *private)
696  {
697  	struct inode *dir = d_inode(parent);
698  	struct dentry *dentry;
699  	int i, err;
700  
701  	inode_lock(dir);
702  	for (i = start; i < eof; i++) {
703  		dentry = __rpc_lookup_create_exclusive(parent, files[i].name);
704  		err = PTR_ERR(dentry);
705  		if (IS_ERR(dentry))
706  			goto out_bad;
707  		switch (files[i].mode & S_IFMT) {
708  			default:
709  				BUG();
710  			case S_IFREG:
711  				err = __rpc_create(dir, dentry,
712  						files[i].mode,
713  						files[i].i_fop,
714  						private);
715  				break;
716  			case S_IFDIR:
717  				err = __rpc_mkdir(dir, dentry,
718  						files[i].mode,
719  						NULL,
720  						private);
721  		}
722  		if (err != 0)
723  			goto out_bad;
724  	}
725  	inode_unlock(dir);
726  	return 0;
727  out_bad:
728  	__rpc_depopulate(parent, files, start, eof);
729  	inode_unlock(dir);
730  	printk(KERN_WARNING "%s: %s failed to populate directory %pd\n",
731  			__FILE__, __func__, parent);
732  	return err;
733  }
734  
rpc_mkdir_populate(struct dentry * parent,const char * name,umode_t mode,void * private,int (* populate)(struct dentry *,void *),void * args_populate)735  static struct dentry *rpc_mkdir_populate(struct dentry *parent,
736  		const char *name, umode_t mode, void *private,
737  		int (*populate)(struct dentry *, void *), void *args_populate)
738  {
739  	struct dentry *dentry;
740  	struct inode *dir = d_inode(parent);
741  	int error;
742  
743  	inode_lock_nested(dir, I_MUTEX_PARENT);
744  	dentry = __rpc_lookup_create_exclusive(parent, name);
745  	if (IS_ERR(dentry))
746  		goto out;
747  	error = __rpc_mkdir(dir, dentry, mode, NULL, private);
748  	if (error != 0)
749  		goto out_err;
750  	if (populate != NULL) {
751  		error = populate(dentry, args_populate);
752  		if (error)
753  			goto err_rmdir;
754  	}
755  out:
756  	inode_unlock(dir);
757  	return dentry;
758  err_rmdir:
759  	__rpc_rmdir(dir, dentry);
760  out_err:
761  	dentry = ERR_PTR(error);
762  	goto out;
763  }
764  
rpc_rmdir_depopulate(struct dentry * dentry,void (* depopulate)(struct dentry *))765  static int rpc_rmdir_depopulate(struct dentry *dentry,
766  		void (*depopulate)(struct dentry *))
767  {
768  	struct dentry *parent;
769  	struct inode *dir;
770  	int error;
771  
772  	parent = dget_parent(dentry);
773  	dir = d_inode(parent);
774  	inode_lock_nested(dir, I_MUTEX_PARENT);
775  	if (depopulate != NULL)
776  		depopulate(dentry);
777  	error = __rpc_rmdir(dir, dentry);
778  	inode_unlock(dir);
779  	dput(parent);
780  	return error;
781  }
782  
783  /**
784   * rpc_mkpipe_dentry - make an rpc_pipefs file for kernel<->userspace
785   *		       communication
786   * @parent: dentry of directory to create new "pipe" in
787   * @name: name of pipe
788   * @private: private data to associate with the pipe, for the caller's use
789   * @pipe: &rpc_pipe containing input parameters
790   *
791   * Data is made available for userspace to read by calls to
792   * rpc_queue_upcall().  The actual reads will result in calls to
793   * @ops->upcall, which will be called with the file pointer,
794   * message, and userspace buffer to copy to.
795   *
796   * Writes can come at any time, and do not necessarily have to be
797   * responses to upcalls.  They will result in calls to @msg->downcall.
798   *
799   * The @private argument passed here will be available to all these methods
800   * from the file pointer, via RPC_I(file_inode(file))->private.
801   */
rpc_mkpipe_dentry(struct dentry * parent,const char * name,void * private,struct rpc_pipe * pipe)802  struct dentry *rpc_mkpipe_dentry(struct dentry *parent, const char *name,
803  				 void *private, struct rpc_pipe *pipe)
804  {
805  	struct dentry *dentry;
806  	struct inode *dir = d_inode(parent);
807  	umode_t umode = S_IFIFO | 0600;
808  	int err;
809  
810  	if (pipe->ops->upcall == NULL)
811  		umode &= ~0444;
812  	if (pipe->ops->downcall == NULL)
813  		umode &= ~0222;
814  
815  	inode_lock_nested(dir, I_MUTEX_PARENT);
816  	dentry = __rpc_lookup_create_exclusive(parent, name);
817  	if (IS_ERR(dentry))
818  		goto out;
819  	err = __rpc_mkpipe_dentry(dir, dentry, umode, &rpc_pipe_fops,
820  				  private, pipe);
821  	if (err)
822  		goto out_err;
823  out:
824  	inode_unlock(dir);
825  	return dentry;
826  out_err:
827  	dentry = ERR_PTR(err);
828  	printk(KERN_WARNING "%s: %s() failed to create pipe %pd/%s (errno = %d)\n",
829  			__FILE__, __func__, parent, name,
830  			err);
831  	goto out;
832  }
833  EXPORT_SYMBOL_GPL(rpc_mkpipe_dentry);
834  
835  /**
836   * rpc_unlink - remove a pipe
837   * @dentry: dentry for the pipe, as returned from rpc_mkpipe
838   *
839   * After this call, lookups will no longer find the pipe, and any
840   * attempts to read or write using preexisting opens of the pipe will
841   * return -EPIPE.
842   */
843  int
rpc_unlink(struct dentry * dentry)844  rpc_unlink(struct dentry *dentry)
845  {
846  	struct dentry *parent;
847  	struct inode *dir;
848  	int error = 0;
849  
850  	parent = dget_parent(dentry);
851  	dir = d_inode(parent);
852  	inode_lock_nested(dir, I_MUTEX_PARENT);
853  	error = __rpc_rmpipe(dir, dentry);
854  	inode_unlock(dir);
855  	dput(parent);
856  	return error;
857  }
858  EXPORT_SYMBOL_GPL(rpc_unlink);
859  
860  /**
861   * rpc_init_pipe_dir_head - initialise a struct rpc_pipe_dir_head
862   * @pdh: pointer to struct rpc_pipe_dir_head
863   */
rpc_init_pipe_dir_head(struct rpc_pipe_dir_head * pdh)864  void rpc_init_pipe_dir_head(struct rpc_pipe_dir_head *pdh)
865  {
866  	INIT_LIST_HEAD(&pdh->pdh_entries);
867  	pdh->pdh_dentry = NULL;
868  }
869  EXPORT_SYMBOL_GPL(rpc_init_pipe_dir_head);
870  
871  /**
872   * rpc_init_pipe_dir_object - initialise a struct rpc_pipe_dir_object
873   * @pdo: pointer to struct rpc_pipe_dir_object
874   * @pdo_ops: pointer to const struct rpc_pipe_dir_object_ops
875   * @pdo_data: pointer to caller-defined data
876   */
rpc_init_pipe_dir_object(struct rpc_pipe_dir_object * pdo,const struct rpc_pipe_dir_object_ops * pdo_ops,void * pdo_data)877  void rpc_init_pipe_dir_object(struct rpc_pipe_dir_object *pdo,
878  		const struct rpc_pipe_dir_object_ops *pdo_ops,
879  		void *pdo_data)
880  {
881  	INIT_LIST_HEAD(&pdo->pdo_head);
882  	pdo->pdo_ops = pdo_ops;
883  	pdo->pdo_data = pdo_data;
884  }
885  EXPORT_SYMBOL_GPL(rpc_init_pipe_dir_object);
886  
887  static int
rpc_add_pipe_dir_object_locked(struct net * net,struct rpc_pipe_dir_head * pdh,struct rpc_pipe_dir_object * pdo)888  rpc_add_pipe_dir_object_locked(struct net *net,
889  		struct rpc_pipe_dir_head *pdh,
890  		struct rpc_pipe_dir_object *pdo)
891  {
892  	int ret = 0;
893  
894  	if (pdh->pdh_dentry)
895  		ret = pdo->pdo_ops->create(pdh->pdh_dentry, pdo);
896  	if (ret == 0)
897  		list_add_tail(&pdo->pdo_head, &pdh->pdh_entries);
898  	return ret;
899  }
900  
901  static void
rpc_remove_pipe_dir_object_locked(struct net * net,struct rpc_pipe_dir_head * pdh,struct rpc_pipe_dir_object * pdo)902  rpc_remove_pipe_dir_object_locked(struct net *net,
903  		struct rpc_pipe_dir_head *pdh,
904  		struct rpc_pipe_dir_object *pdo)
905  {
906  	if (pdh->pdh_dentry)
907  		pdo->pdo_ops->destroy(pdh->pdh_dentry, pdo);
908  	list_del_init(&pdo->pdo_head);
909  }
910  
911  /**
912   * rpc_add_pipe_dir_object - associate a rpc_pipe_dir_object to a directory
913   * @net: pointer to struct net
914   * @pdh: pointer to struct rpc_pipe_dir_head
915   * @pdo: pointer to struct rpc_pipe_dir_object
916   *
917   */
918  int
rpc_add_pipe_dir_object(struct net * net,struct rpc_pipe_dir_head * pdh,struct rpc_pipe_dir_object * pdo)919  rpc_add_pipe_dir_object(struct net *net,
920  		struct rpc_pipe_dir_head *pdh,
921  		struct rpc_pipe_dir_object *pdo)
922  {
923  	int ret = 0;
924  
925  	if (list_empty(&pdo->pdo_head)) {
926  		struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
927  
928  		mutex_lock(&sn->pipefs_sb_lock);
929  		ret = rpc_add_pipe_dir_object_locked(net, pdh, pdo);
930  		mutex_unlock(&sn->pipefs_sb_lock);
931  	}
932  	return ret;
933  }
934  EXPORT_SYMBOL_GPL(rpc_add_pipe_dir_object);
935  
936  /**
937   * rpc_remove_pipe_dir_object - remove a rpc_pipe_dir_object from a directory
938   * @net: pointer to struct net
939   * @pdh: pointer to struct rpc_pipe_dir_head
940   * @pdo: pointer to struct rpc_pipe_dir_object
941   *
942   */
943  void
rpc_remove_pipe_dir_object(struct net * net,struct rpc_pipe_dir_head * pdh,struct rpc_pipe_dir_object * pdo)944  rpc_remove_pipe_dir_object(struct net *net,
945  		struct rpc_pipe_dir_head *pdh,
946  		struct rpc_pipe_dir_object *pdo)
947  {
948  	if (!list_empty(&pdo->pdo_head)) {
949  		struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
950  
951  		mutex_lock(&sn->pipefs_sb_lock);
952  		rpc_remove_pipe_dir_object_locked(net, pdh, pdo);
953  		mutex_unlock(&sn->pipefs_sb_lock);
954  	}
955  }
956  EXPORT_SYMBOL_GPL(rpc_remove_pipe_dir_object);
957  
958  /**
959   * rpc_find_or_alloc_pipe_dir_object
960   * @net: pointer to struct net
961   * @pdh: pointer to struct rpc_pipe_dir_head
962   * @match: match struct rpc_pipe_dir_object to data
963   * @alloc: allocate a new struct rpc_pipe_dir_object
964   * @data: user defined data for match() and alloc()
965   *
966   */
967  struct rpc_pipe_dir_object *
rpc_find_or_alloc_pipe_dir_object(struct net * net,struct rpc_pipe_dir_head * pdh,int (* match)(struct rpc_pipe_dir_object *,void *),struct rpc_pipe_dir_object * (* alloc)(void *),void * data)968  rpc_find_or_alloc_pipe_dir_object(struct net *net,
969  		struct rpc_pipe_dir_head *pdh,
970  		int (*match)(struct rpc_pipe_dir_object *, void *),
971  		struct rpc_pipe_dir_object *(*alloc)(void *),
972  		void *data)
973  {
974  	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
975  	struct rpc_pipe_dir_object *pdo;
976  
977  	mutex_lock(&sn->pipefs_sb_lock);
978  	list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head) {
979  		if (!match(pdo, data))
980  			continue;
981  		goto out;
982  	}
983  	pdo = alloc(data);
984  	if (!pdo)
985  		goto out;
986  	rpc_add_pipe_dir_object_locked(net, pdh, pdo);
987  out:
988  	mutex_unlock(&sn->pipefs_sb_lock);
989  	return pdo;
990  }
991  EXPORT_SYMBOL_GPL(rpc_find_or_alloc_pipe_dir_object);
992  
993  static void
rpc_create_pipe_dir_objects(struct rpc_pipe_dir_head * pdh)994  rpc_create_pipe_dir_objects(struct rpc_pipe_dir_head *pdh)
995  {
996  	struct rpc_pipe_dir_object *pdo;
997  	struct dentry *dir = pdh->pdh_dentry;
998  
999  	list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head)
1000  		pdo->pdo_ops->create(dir, pdo);
1001  }
1002  
1003  static void
rpc_destroy_pipe_dir_objects(struct rpc_pipe_dir_head * pdh)1004  rpc_destroy_pipe_dir_objects(struct rpc_pipe_dir_head *pdh)
1005  {
1006  	struct rpc_pipe_dir_object *pdo;
1007  	struct dentry *dir = pdh->pdh_dentry;
1008  
1009  	list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head)
1010  		pdo->pdo_ops->destroy(dir, pdo);
1011  }
1012  
1013  enum {
1014  	RPCAUTH_info,
1015  	RPCAUTH_EOF
1016  };
1017  
1018  static const struct rpc_filelist authfiles[] = {
1019  	[RPCAUTH_info] = {
1020  		.name = "info",
1021  		.i_fop = &rpc_info_operations,
1022  		.mode = S_IFREG | 0400,
1023  	},
1024  };
1025  
rpc_clntdir_populate(struct dentry * dentry,void * private)1026  static int rpc_clntdir_populate(struct dentry *dentry, void *private)
1027  {
1028  	return rpc_populate(dentry,
1029  			    authfiles, RPCAUTH_info, RPCAUTH_EOF,
1030  			    private);
1031  }
1032  
rpc_clntdir_depopulate(struct dentry * dentry)1033  static void rpc_clntdir_depopulate(struct dentry *dentry)
1034  {
1035  	rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
1036  }
1037  
1038  /**
1039   * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
1040   * @dentry: the parent of new directory
1041   * @name: the name of new directory
1042   * @rpc_client: rpc client to associate with this directory
1043   *
1044   * This creates a directory at the given @path associated with
1045   * @rpc_clnt, which will contain a file named "info" with some basic
1046   * information about the client, together with any "pipes" that may
1047   * later be created using rpc_mkpipe().
1048   */
rpc_create_client_dir(struct dentry * dentry,const char * name,struct rpc_clnt * rpc_client)1049  struct dentry *rpc_create_client_dir(struct dentry *dentry,
1050  				   const char *name,
1051  				   struct rpc_clnt *rpc_client)
1052  {
1053  	struct dentry *ret;
1054  
1055  	ret = rpc_mkdir_populate(dentry, name, 0555, NULL,
1056  				 rpc_clntdir_populate, rpc_client);
1057  	if (!IS_ERR(ret)) {
1058  		rpc_client->cl_pipedir_objects.pdh_dentry = ret;
1059  		rpc_create_pipe_dir_objects(&rpc_client->cl_pipedir_objects);
1060  	}
1061  	return ret;
1062  }
1063  
1064  /**
1065   * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
1066   * @rpc_client: rpc_client for the pipe
1067   */
rpc_remove_client_dir(struct rpc_clnt * rpc_client)1068  int rpc_remove_client_dir(struct rpc_clnt *rpc_client)
1069  {
1070  	struct dentry *dentry = rpc_client->cl_pipedir_objects.pdh_dentry;
1071  
1072  	if (dentry == NULL)
1073  		return 0;
1074  	rpc_destroy_pipe_dir_objects(&rpc_client->cl_pipedir_objects);
1075  	rpc_client->cl_pipedir_objects.pdh_dentry = NULL;
1076  	return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
1077  }
1078  
1079  static const struct rpc_filelist cache_pipefs_files[3] = {
1080  	[0] = {
1081  		.name = "channel",
1082  		.i_fop = &cache_file_operations_pipefs,
1083  		.mode = S_IFREG | 0600,
1084  	},
1085  	[1] = {
1086  		.name = "content",
1087  		.i_fop = &content_file_operations_pipefs,
1088  		.mode = S_IFREG | 0400,
1089  	},
1090  	[2] = {
1091  		.name = "flush",
1092  		.i_fop = &cache_flush_operations_pipefs,
1093  		.mode = S_IFREG | 0600,
1094  	},
1095  };
1096  
rpc_cachedir_populate(struct dentry * dentry,void * private)1097  static int rpc_cachedir_populate(struct dentry *dentry, void *private)
1098  {
1099  	return rpc_populate(dentry,
1100  			    cache_pipefs_files, 0, 3,
1101  			    private);
1102  }
1103  
rpc_cachedir_depopulate(struct dentry * dentry)1104  static void rpc_cachedir_depopulate(struct dentry *dentry)
1105  {
1106  	rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
1107  }
1108  
rpc_create_cache_dir(struct dentry * parent,const char * name,umode_t umode,struct cache_detail * cd)1109  struct dentry *rpc_create_cache_dir(struct dentry *parent, const char *name,
1110  				    umode_t umode, struct cache_detail *cd)
1111  {
1112  	return rpc_mkdir_populate(parent, name, umode, NULL,
1113  			rpc_cachedir_populate, cd);
1114  }
1115  
rpc_remove_cache_dir(struct dentry * dentry)1116  void rpc_remove_cache_dir(struct dentry *dentry)
1117  {
1118  	rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
1119  }
1120  
1121  /*
1122   * populate the filesystem
1123   */
1124  static const struct super_operations s_ops = {
1125  	.alloc_inode	= rpc_alloc_inode,
1126  	.free_inode	= rpc_free_inode,
1127  	.statfs		= simple_statfs,
1128  };
1129  
1130  #define RPCAUTH_GSSMAGIC 0x67596969
1131  
1132  /*
1133   * We have a single directory with 1 node in it.
1134   */
1135  enum {
1136  	RPCAUTH_lockd,
1137  	RPCAUTH_mount,
1138  	RPCAUTH_nfs,
1139  	RPCAUTH_portmap,
1140  	RPCAUTH_statd,
1141  	RPCAUTH_nfsd4_cb,
1142  	RPCAUTH_cache,
1143  	RPCAUTH_nfsd,
1144  	RPCAUTH_gssd,
1145  	RPCAUTH_RootEOF
1146  };
1147  
1148  static const struct rpc_filelist files[] = {
1149  	[RPCAUTH_lockd] = {
1150  		.name = "lockd",
1151  		.mode = S_IFDIR | 0555,
1152  	},
1153  	[RPCAUTH_mount] = {
1154  		.name = "mount",
1155  		.mode = S_IFDIR | 0555,
1156  	},
1157  	[RPCAUTH_nfs] = {
1158  		.name = "nfs",
1159  		.mode = S_IFDIR | 0555,
1160  	},
1161  	[RPCAUTH_portmap] = {
1162  		.name = "portmap",
1163  		.mode = S_IFDIR | 0555,
1164  	},
1165  	[RPCAUTH_statd] = {
1166  		.name = "statd",
1167  		.mode = S_IFDIR | 0555,
1168  	},
1169  	[RPCAUTH_nfsd4_cb] = {
1170  		.name = "nfsd4_cb",
1171  		.mode = S_IFDIR | 0555,
1172  	},
1173  	[RPCAUTH_cache] = {
1174  		.name = "cache",
1175  		.mode = S_IFDIR | 0555,
1176  	},
1177  	[RPCAUTH_nfsd] = {
1178  		.name = "nfsd",
1179  		.mode = S_IFDIR | 0555,
1180  	},
1181  	[RPCAUTH_gssd] = {
1182  		.name = "gssd",
1183  		.mode = S_IFDIR | 0555,
1184  	},
1185  };
1186  
1187  /*
1188   * This call can be used only in RPC pipefs mount notification hooks.
1189   */
rpc_d_lookup_sb(const struct super_block * sb,const unsigned char * dir_name)1190  struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
1191  			       const unsigned char *dir_name)
1192  {
1193  	struct qstr dir = QSTR_INIT(dir_name, strlen(dir_name));
1194  	return d_hash_and_lookup(sb->s_root, &dir);
1195  }
1196  EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);
1197  
rpc_pipefs_init_net(struct net * net)1198  int rpc_pipefs_init_net(struct net *net)
1199  {
1200  	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1201  
1202  	sn->gssd_dummy = rpc_mkpipe_data(&gssd_dummy_pipe_ops, 0);
1203  	if (IS_ERR(sn->gssd_dummy))
1204  		return PTR_ERR(sn->gssd_dummy);
1205  
1206  	mutex_init(&sn->pipefs_sb_lock);
1207  	sn->pipe_version = -1;
1208  	return 0;
1209  }
1210  
rpc_pipefs_exit_net(struct net * net)1211  void rpc_pipefs_exit_net(struct net *net)
1212  {
1213  	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1214  
1215  	rpc_destroy_pipe_data(sn->gssd_dummy);
1216  }
1217  
1218  /*
1219   * This call will be used for per network namespace operations calls.
1220   * Note: Function will be returned with pipefs_sb_lock taken if superblock was
1221   * found. This lock have to be released by rpc_put_sb_net() when all operations
1222   * will be completed.
1223   */
rpc_get_sb_net(const struct net * net)1224  struct super_block *rpc_get_sb_net(const struct net *net)
1225  {
1226  	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1227  
1228  	mutex_lock(&sn->pipefs_sb_lock);
1229  	if (sn->pipefs_sb)
1230  		return sn->pipefs_sb;
1231  	mutex_unlock(&sn->pipefs_sb_lock);
1232  	return NULL;
1233  }
1234  EXPORT_SYMBOL_GPL(rpc_get_sb_net);
1235  
rpc_put_sb_net(const struct net * net)1236  void rpc_put_sb_net(const struct net *net)
1237  {
1238  	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1239  
1240  	WARN_ON(sn->pipefs_sb == NULL);
1241  	mutex_unlock(&sn->pipefs_sb_lock);
1242  }
1243  EXPORT_SYMBOL_GPL(rpc_put_sb_net);
1244  
1245  static const struct rpc_filelist gssd_dummy_clnt_dir[] = {
1246  	[0] = {
1247  		.name = "clntXX",
1248  		.mode = S_IFDIR | 0555,
1249  	},
1250  };
1251  
1252  static ssize_t
dummy_downcall(struct file * filp,const char __user * src,size_t len)1253  dummy_downcall(struct file *filp, const char __user *src, size_t len)
1254  {
1255  	return -EINVAL;
1256  }
1257  
1258  static const struct rpc_pipe_ops gssd_dummy_pipe_ops = {
1259  	.upcall		= rpc_pipe_generic_upcall,
1260  	.downcall	= dummy_downcall,
1261  };
1262  
1263  /*
1264   * Here we present a bogus "info" file to keep rpc.gssd happy. We don't expect
1265   * that it will ever use this info to handle an upcall, but rpc.gssd expects
1266   * that this file will be there and have a certain format.
1267   */
1268  static int
rpc_dummy_info_show(struct seq_file * m,void * v)1269  rpc_dummy_info_show(struct seq_file *m, void *v)
1270  {
1271  	seq_printf(m, "RPC server: %s\n", utsname()->nodename);
1272  	seq_printf(m, "service: foo (1) version 0\n");
1273  	seq_printf(m, "address: 127.0.0.1\n");
1274  	seq_printf(m, "protocol: tcp\n");
1275  	seq_printf(m, "port: 0\n");
1276  	return 0;
1277  }
1278  DEFINE_SHOW_ATTRIBUTE(rpc_dummy_info);
1279  
1280  static const struct rpc_filelist gssd_dummy_info_file[] = {
1281  	[0] = {
1282  		.name = "info",
1283  		.i_fop = &rpc_dummy_info_fops,
1284  		.mode = S_IFREG | 0400,
1285  	},
1286  };
1287  
1288  /**
1289   * rpc_gssd_dummy_populate - create a dummy gssd pipe
1290   * @root:	root of the rpc_pipefs filesystem
1291   * @pipe_data:	pipe data created when netns is initialized
1292   *
1293   * Create a dummy set of directories and a pipe that gssd can hold open to
1294   * indicate that it is up and running.
1295   */
1296  static struct dentry *
rpc_gssd_dummy_populate(struct dentry * root,struct rpc_pipe * pipe_data)1297  rpc_gssd_dummy_populate(struct dentry *root, struct rpc_pipe *pipe_data)
1298  {
1299  	int ret = 0;
1300  	struct dentry *gssd_dentry;
1301  	struct dentry *clnt_dentry = NULL;
1302  	struct dentry *pipe_dentry = NULL;
1303  	struct qstr q = QSTR_INIT(files[RPCAUTH_gssd].name,
1304  				  strlen(files[RPCAUTH_gssd].name));
1305  
1306  	/* We should never get this far if "gssd" doesn't exist */
1307  	gssd_dentry = d_hash_and_lookup(root, &q);
1308  	if (!gssd_dentry)
1309  		return ERR_PTR(-ENOENT);
1310  
1311  	ret = rpc_populate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1, NULL);
1312  	if (ret) {
1313  		pipe_dentry = ERR_PTR(ret);
1314  		goto out;
1315  	}
1316  
1317  	q.name = gssd_dummy_clnt_dir[0].name;
1318  	q.len = strlen(gssd_dummy_clnt_dir[0].name);
1319  	clnt_dentry = d_hash_and_lookup(gssd_dentry, &q);
1320  	if (!clnt_dentry) {
1321  		__rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1322  		pipe_dentry = ERR_PTR(-ENOENT);
1323  		goto out;
1324  	}
1325  
1326  	ret = rpc_populate(clnt_dentry, gssd_dummy_info_file, 0, 1, NULL);
1327  	if (ret) {
1328  		__rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1329  		pipe_dentry = ERR_PTR(ret);
1330  		goto out;
1331  	}
1332  
1333  	pipe_dentry = rpc_mkpipe_dentry(clnt_dentry, "gssd", NULL, pipe_data);
1334  	if (IS_ERR(pipe_dentry)) {
1335  		__rpc_depopulate(clnt_dentry, gssd_dummy_info_file, 0, 1);
1336  		__rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1337  	}
1338  out:
1339  	dput(clnt_dentry);
1340  	dput(gssd_dentry);
1341  	return pipe_dentry;
1342  }
1343  
1344  static void
rpc_gssd_dummy_depopulate(struct dentry * pipe_dentry)1345  rpc_gssd_dummy_depopulate(struct dentry *pipe_dentry)
1346  {
1347  	struct dentry *clnt_dir = pipe_dentry->d_parent;
1348  	struct dentry *gssd_dir = clnt_dir->d_parent;
1349  
1350  	dget(pipe_dentry);
1351  	__rpc_rmpipe(d_inode(clnt_dir), pipe_dentry);
1352  	__rpc_depopulate(clnt_dir, gssd_dummy_info_file, 0, 1);
1353  	__rpc_depopulate(gssd_dir, gssd_dummy_clnt_dir, 0, 1);
1354  	dput(pipe_dentry);
1355  }
1356  
1357  static int
rpc_fill_super(struct super_block * sb,struct fs_context * fc)1358  rpc_fill_super(struct super_block *sb, struct fs_context *fc)
1359  {
1360  	struct inode *inode;
1361  	struct dentry *root, *gssd_dentry;
1362  	struct net *net = sb->s_fs_info;
1363  	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1364  	int err;
1365  
1366  	sb->s_blocksize = PAGE_SIZE;
1367  	sb->s_blocksize_bits = PAGE_SHIFT;
1368  	sb->s_magic = RPCAUTH_GSSMAGIC;
1369  	sb->s_op = &s_ops;
1370  	sb->s_d_op = &simple_dentry_operations;
1371  	sb->s_time_gran = 1;
1372  
1373  	inode = rpc_get_inode(sb, S_IFDIR | 0555);
1374  	sb->s_root = root = d_make_root(inode);
1375  	if (!root)
1376  		return -ENOMEM;
1377  	if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1378  		return -ENOMEM;
1379  
1380  	gssd_dentry = rpc_gssd_dummy_populate(root, sn->gssd_dummy);
1381  	if (IS_ERR(gssd_dentry)) {
1382  		__rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1383  		return PTR_ERR(gssd_dentry);
1384  	}
1385  
1386  	dprintk("RPC:       sending pipefs MOUNT notification for net %x%s\n",
1387  		net->ns.inum, NET_NAME(net));
1388  	mutex_lock(&sn->pipefs_sb_lock);
1389  	sn->pipefs_sb = sb;
1390  	err = blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1391  					   RPC_PIPEFS_MOUNT,
1392  					   sb);
1393  	if (err)
1394  		goto err_depopulate;
1395  	mutex_unlock(&sn->pipefs_sb_lock);
1396  	return 0;
1397  
1398  err_depopulate:
1399  	rpc_gssd_dummy_depopulate(gssd_dentry);
1400  	blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1401  					   RPC_PIPEFS_UMOUNT,
1402  					   sb);
1403  	sn->pipefs_sb = NULL;
1404  	__rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1405  	mutex_unlock(&sn->pipefs_sb_lock);
1406  	return err;
1407  }
1408  
1409  bool
gssd_running(struct net * net)1410  gssd_running(struct net *net)
1411  {
1412  	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1413  	struct rpc_pipe *pipe = sn->gssd_dummy;
1414  
1415  	return pipe->nreaders || pipe->nwriters;
1416  }
1417  EXPORT_SYMBOL_GPL(gssd_running);
1418  
rpc_fs_get_tree(struct fs_context * fc)1419  static int rpc_fs_get_tree(struct fs_context *fc)
1420  {
1421  	return get_tree_keyed(fc, rpc_fill_super, get_net(fc->net_ns));
1422  }
1423  
rpc_fs_free_fc(struct fs_context * fc)1424  static void rpc_fs_free_fc(struct fs_context *fc)
1425  {
1426  	if (fc->s_fs_info)
1427  		put_net(fc->s_fs_info);
1428  }
1429  
1430  static const struct fs_context_operations rpc_fs_context_ops = {
1431  	.free		= rpc_fs_free_fc,
1432  	.get_tree	= rpc_fs_get_tree,
1433  };
1434  
rpc_init_fs_context(struct fs_context * fc)1435  static int rpc_init_fs_context(struct fs_context *fc)
1436  {
1437  	put_user_ns(fc->user_ns);
1438  	fc->user_ns = get_user_ns(fc->net_ns->user_ns);
1439  	fc->ops = &rpc_fs_context_ops;
1440  	return 0;
1441  }
1442  
rpc_kill_sb(struct super_block * sb)1443  static void rpc_kill_sb(struct super_block *sb)
1444  {
1445  	struct net *net = sb->s_fs_info;
1446  	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1447  
1448  	mutex_lock(&sn->pipefs_sb_lock);
1449  	if (sn->pipefs_sb != sb) {
1450  		mutex_unlock(&sn->pipefs_sb_lock);
1451  		goto out;
1452  	}
1453  	sn->pipefs_sb = NULL;
1454  	dprintk("RPC:       sending pipefs UMOUNT notification for net %x%s\n",
1455  		net->ns.inum, NET_NAME(net));
1456  	blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1457  					   RPC_PIPEFS_UMOUNT,
1458  					   sb);
1459  	mutex_unlock(&sn->pipefs_sb_lock);
1460  out:
1461  	kill_litter_super(sb);
1462  	put_net(net);
1463  }
1464  
1465  static struct file_system_type rpc_pipe_fs_type = {
1466  	.owner		= THIS_MODULE,
1467  	.name		= "rpc_pipefs",
1468  	.init_fs_context = rpc_init_fs_context,
1469  	.kill_sb	= rpc_kill_sb,
1470  };
1471  MODULE_ALIAS_FS("rpc_pipefs");
1472  MODULE_ALIAS("rpc_pipefs");
1473  
1474  static void
init_once(void * foo)1475  init_once(void *foo)
1476  {
1477  	struct rpc_inode *rpci = (struct rpc_inode *) foo;
1478  
1479  	inode_init_once(&rpci->vfs_inode);
1480  	rpci->private = NULL;
1481  	rpci->pipe = NULL;
1482  	init_waitqueue_head(&rpci->waitq);
1483  }
1484  
register_rpc_pipefs(void)1485  int register_rpc_pipefs(void)
1486  {
1487  	int err;
1488  
1489  	rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1490  				sizeof(struct rpc_inode),
1491  				0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1492  						SLAB_ACCOUNT),
1493  				init_once);
1494  	if (!rpc_inode_cachep)
1495  		return -ENOMEM;
1496  	err = rpc_clients_notifier_register();
1497  	if (err)
1498  		goto err_notifier;
1499  	err = register_filesystem(&rpc_pipe_fs_type);
1500  	if (err)
1501  		goto err_register;
1502  	return 0;
1503  
1504  err_register:
1505  	rpc_clients_notifier_unregister();
1506  err_notifier:
1507  	kmem_cache_destroy(rpc_inode_cachep);
1508  	return err;
1509  }
1510  
unregister_rpc_pipefs(void)1511  void unregister_rpc_pipefs(void)
1512  {
1513  	rpc_clients_notifier_unregister();
1514  	unregister_filesystem(&rpc_pipe_fs_type);
1515  	kmem_cache_destroy(rpc_inode_cachep);
1516  }
1517