path: root/net/sunrpc/rpc_pipe.c

/*
 * net/sunrpc/rpc_pipe.c
 *
 * Userland/kernel interface for rpcauth_gss.
 * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
 * and fs/sysfs/inode.c
 *
 * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
 *
 */
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/pagemap.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/fsnotify.h>
#include <linux/kernel.h>

#include <asm/ioctls.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/wait.h>
#include <linux/seq_file.h>

#include <linux/sunrpc/clnt.h>
#include <linux/workqueue.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include <linux/sunrpc/cache.h>
#include <linux/nsproxy.h>
#include <linux/notifier.h>

#include "netns.h"
#include "sunrpc.h"

static struct vfsmount *rpc_mnt __read_mostly;
static int rpc_mount_count;

static struct file_system_type rpc_pipe_fs_type;


static struct kmem_cache *rpc_inode_cachep __read_mostly;

#define RPC_UPCALL_TIMEOUT (30*HZ)

static BLOCKING_NOTIFIER_HEAD(rpc_pipefs_notifier_list);

int rpc_pipefs_notifier_register(struct notifier_block *nb)
{
	return blocking_notifier_chain_cond_register(&rpc_pipefs_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_register);

void rpc_pipefs_notifier_unregister(struct notifier_block *nb)
{
	blocking_notifier_chain_unregister(&rpc_pipefs_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_unregister);

static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
		void (*destroy_msg)(struct rpc_pipe_msg *), int err)
{
	struct rpc_pipe_msg *msg;

	if (list_empty(head))
		return;
	do {
		msg = list_entry(head->next, struct rpc_pipe_msg, list);
		list_del_init(&msg->list);
		msg->errno = err;
		destroy_msg(msg);
	} while (!list_empty(head));
	wake_up(&rpci->waitq);
}

static void
rpc_timeout_upcall_queue(struct work_struct *work)
{
	LIST_HEAD(free_list);
	struct rpc_inode *rpci =
		container_of(work, struct rpc_inode, queue_timeout.work);
	struct inode *inode = &rpci->vfs_inode;
	void (*destroy_msg)(struct rpc_pipe_msg *);

	spin_lock(&inode->i_lock);
	if (rpci->ops == NULL) {
		spin_unlock(&inode->i_lock);
		return;
	}
	destroy_msg = rpci->ops->destroy_msg;
	if (rpci->nreaders == 0) {
		list_splice_init(&rpci->pipe, &free_list);
		rpci->pipelen = 0;
	}
	spin_unlock(&inode->i_lock);
	rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
}

ssize_t rpc_pipe_generic_upcall(struct file *filp, struct rpc_pipe_msg *msg,
				char __user *dst, size_t buflen)
{
	char *data = (char *)msg->data + msg->copied;
	size_t mlen = min(msg->len - msg->copied, buflen);
	unsigned long left;

	left = copy_to_user(dst, data, mlen);
	if (left == mlen) {
		msg->errno = -EFAULT;
		return -EFAULT;
	}

	mlen -= left;
	msg->copied += mlen;
	msg->errno = 0;
	return mlen;
}
EXPORT_SYMBOL_GPL(rpc_pipe_generic_upcall);

/**
 * rpc_queue_upcall - queue an upcall message to userspace
 * @inode: inode of upcall pipe on which to queue given message