Merge branch 'cuse' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

source "fs/autofs4/Kconfig"

source "fs/fuse/Kconfig"

config CUSE

	tristate "Character device in Userpace support"

	depends on FUSE_FS

	help

	  This FUSE extension allows character devices to be

	  implemented in userspace.

	  If you want to develop or use userspace character device

	  based on CUSE, answer Y or M.

config GENERIC_ACL

	bool

	select FS_POSIX_ACL

#

obj-$(CONFIG_FUSE_FS) += fuse.o

obj-$(CONFIG_CUSE) += cuse.o

fuse-objs := dev.o dir.o file.o inode.o control.o

/*

 * CUSE: Character device in Userspace

 *

 * Copyright (C) 2008-2009  SUSE Linux Products GmbH

 * Copyright (C) 2008-2009  Tejun Heo <tj@kernel.org>

 *

 * This file is released under the GPLv2.

 *

 * CUSE enables character devices to be implemented from userland much

 * like FUSE allows filesystems.  On initialization /dev/cuse is

 * created.  By opening the file and replying to the CUSE_INIT request

 * userland CUSE server can create a character device.  After that the

 * operation is very similar to FUSE.

 *

 * A CUSE instance involves the following objects.

 *

 * cuse_conn	: contains fuse_conn and serves as bonding structure

 * channel	: file handle connected to the userland CUSE server

 * cdev		: the implemented character device

 * dev		: generic device for cdev

 *

 * Note that 'channel' is what 'dev' is in FUSE.  As CUSE deals with

 * devices, it's called 'channel' to reduce confusion.

 *

 * channel determines when the character device dies.  When channel is

 * closed, everything begins to destruct.  The cuse_conn is taken off

 * the lookup table preventing further access from cdev, cdev and

 * generic device are removed and the base reference of cuse_conn is

 * put.

 *

 * On each open, the matching cuse_conn is looked up and if found an

 * additional reference is taken which is released when the file is

 * closed.

 */

#include <linux/fuse.h>

#include <linux/cdev.h>

#include <linux/device.h>

#include <linux/file.h>

#include <linux/fs.h>

#include <linux/kdev_t.h>

#include <linux/kthread.h>

#include <linux/list.h>

#include <linux/magic.h>

#include <linux/miscdevice.h>

#include <linux/mutex.h>

#include <linux/spinlock.h>

#include <linux/stat.h>

#include "fuse_i.h"

#define CUSE_CONNTBL_LEN	64

struct cuse_conn {

	struct list_head	list;	/* linked on cuse_conntbl */

	struct fuse_conn	fc;	/* fuse connection */

	struct cdev		*cdev;	/* associated character device */

	struct device		*dev;	/* device representing @cdev */

	/* init parameters, set once during initialization */

	bool			unrestricted_ioctl;

};

static DEFINE_SPINLOCK(cuse_lock);		/* protects cuse_conntbl */

static struct list_head cuse_conntbl[CUSE_CONNTBL_LEN];

static struct class *cuse_class;

static struct cuse_conn *fc_to_cc(struct fuse_conn *fc)

{

	return container_of(fc, struct cuse_conn, fc);

}

static struct list_head *cuse_conntbl_head(dev_t devt)

{

	return &cuse_conntbl[(MAJOR(devt) + MINOR(devt)) % CUSE_CONNTBL_LEN];

}

/**************************************************************************

 * CUSE frontend operations

 *

 * These are file operations for the character device.

 *

 * On open, CUSE opens a file from the FUSE mnt and stores it to

 * private_data of the open file.  All other ops call FUSE ops on the

 * FUSE file.

 */

static ssize_t cuse_read(struct file *file, char __user *buf, size_t count,

			 loff_t *ppos)

{

	loff_t pos = 0;

	return fuse_direct_io(file, buf, count, &pos, 0);

}

static ssize_t cuse_write(struct file *file, const char __user *buf,

			  size_t count, loff_t *ppos)

{

	loff_t pos = 0;

	/*

	 * No locking or generic_write_checks(), the server is

	 * responsible for locking and sanity checks.

	 */

	return fuse_direct_io(file, buf, count, &pos, 1);

}

static int cuse_open(struct inode *inode, struct file *file)

{

	dev_t devt = inode->i_cdev->dev;

	struct cuse_conn *cc = NULL, *pos;

	int rc;

	/* look up and get the connection */

	spin_lock(&cuse_lock);

	list_for_each_entry(pos, cuse_conntbl_head(devt), list)

		if (pos->dev->devt == devt) {

			fuse_conn_get(&pos->fc);

			cc = pos;

			break;

		}

	spin_unlock(&cuse_lock);

	/* dead? */

	if (!cc)

		return -ENODEV;

	/*

	 * Generic permission check is already done against the chrdev

	 * file, proceed to open.

	 */

	rc = fuse_do_open(&cc->fc, 0, file, 0);

	if (rc)

		fuse_conn_put(&cc->fc);

	return rc;

}

static int cuse_release(struct inode *inode, struct file *file)

{

	struct fuse_file *ff = file->private_data;

	struct fuse_conn *fc = ff->fc;

	fuse_sync_release(ff, file->f_flags);

	fuse_conn_put(fc);

	return 0;

}

static long cuse_file_ioctl(struct file *file, unsigned int cmd,

			    unsigned long arg)

{

	struct fuse_file *ff = file->private_data;

	struct cuse_conn *cc = fc_to_cc(ff->fc);

	unsigned int flags = 0;

	if (cc->unrestricted_ioctl)

		flags |= FUSE_IOCTL_UNRESTRICTED;

	return fuse_do_ioctl(file, cmd, arg, flags);

}

static long cuse_file_compat_ioctl(struct file *file, unsigned int cmd,

				   unsigned long arg)

{

	struct fuse_file *ff = file->private_data;

	struct cuse_conn *cc = fc_to_cc(ff->fc);

	unsigned int flags = FUSE_IOCTL_COMPAT;

	if (cc->unrestricted_ioctl)

		flags |= FUSE_IOCTL_UNRESTRICTED;

	return fuse_do_ioctl(file, cmd, arg, flags);

}

static const struct file_operations cuse_frontend_fops = {

	.owner			= THIS_MODULE,

	.read			= cuse_read,

	.write			= cuse_write,

	.open			= cuse_open,

	.release		= cuse_release,

	.unlocked_ioctl		= cuse_file_ioctl,

	.compat_ioctl		= cuse_file_compat_ioctl,

	.poll			= fuse_file_poll,

};

/**************************************************************************

 * CUSE channel initialization and destruction

 */

struct cuse_devinfo {

	const char		*name;

};

/**

 * cuse_parse_one - parse one key=value pair

 * @pp: i/o parameter for the current position

 * @end: points to one past the end of the packed string

 * @keyp: out parameter for key

 * @valp: out parameter for value

 *

 * *@pp points to packed strings - "key0=val0\0key1=val1\0" which ends

 * at @end - 1.  This function parses one pair and set *@keyp to the

 * start of the key and *@valp to the start of the value.  Note that

 * the original string is modified such that the key string is

 * terminated with '\0'.  *@pp is updated to point to the next string.

 *

 * RETURNS:

 * 1 on successful parse, 0 on EOF, -errno on failure.

 */

static int cuse_parse_one(char **pp, char *end, char **keyp, char **valp)

{

	char *p = *pp;

	char *key, *val;

	while (p < end && *p == '\0')

		p++;

	if (p == end)

		return 0;

	if (end[-1] != '\0') {

		printk(KERN_ERR "CUSE: info not properly terminated\n");

		return -EINVAL;

	}

	key = val = p;

	p += strlen(p);

	if (valp) {

		strsep(&val, "=");

		if (!val)

			val = key + strlen(key);

		key = strstrip(key);

		val = strstrip(val);

	} else

		key = strstrip(key);

	if (!strlen(key)) {

		printk(KERN_ERR "CUSE: zero length info key specified\n");

		return -EINVAL;

	}

	*pp = p;

	*keyp = key;

	if (valp)

		*valp = val;

	return 1;

}

/**

 * cuse_parse_dev_info - parse device info

 * @p: device info string

 * @len: length of device info string

 * @devinfo: out parameter for parsed device info

 *

 * Parse @p to extract device info and store it into @devinfo.  String

 * pointed to by @p is modified by parsing and @devinfo points into

 * them, so @p shouldn't be freed while @devinfo is in use.

 *

 * RETURNS:

 * 0 on success, -errno on failure.

 */

static int cuse_parse_devinfo(char *p, size_t len, struct cuse_devinfo *devinfo)

{

	char *end = p + len;

	char *key, *val;

	int rc;

	while (true) {

		rc = cuse_parse_one(&p, end, &key, &val);

		if (rc < 0)

			return rc;

		if (!rc)

			break;

		if (strcmp(key, "DEVNAME") == 0)

			devinfo->name = val;

		else

			printk(KERN_WARNING "CUSE: unknown device info \"%s\"\n",

			       key);

	}

	if (!devinfo->name || !strlen(devinfo->name)) {

		printk(KERN_ERR "CUSE: DEVNAME unspecified\n");

		return -EINVAL;

	}

	return 0;

}

static void cuse_gendev_release(struct device *dev)

{

	kfree(dev);

}

/**

 * cuse_process_init_reply - finish initializing CUSE channel

 *

 * This function creates the character device and sets up all the

 * required data structures for it.  Please read the comment at the

 * top of this file for high level overview.

 */

static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)

{

	struct cuse_conn *cc = fc_to_cc(fc);

	struct cuse_init_out *arg = &req->misc.cuse_init_out;

	struct page *page = req->pages[0];

	struct cuse_devinfo devinfo = { };

	struct device *dev;

	struct cdev *cdev;

	dev_t devt;

	int rc;

	if (req->out.h.error ||

	    arg->major != FUSE_KERNEL_VERSION || arg->minor < 11) {

		goto err;

	}

	fc->minor = arg->minor;

	fc->max_read = max_t(unsigned, arg->max_read, 4096);

	fc->max_write = max_t(unsigned, arg->max_write, 4096);

	/* parse init reply */

	cc->unrestricted_ioctl = arg->flags & CUSE_UNRESTRICTED_IOCTL;

	rc = cuse_parse_devinfo(page_address(page), req->out.args[1].size,

				&devinfo);

	if (rc)

		goto err;

	/* determine and reserve devt */

	devt = MKDEV(arg->dev_major, arg->dev_minor);

	if (!MAJOR(devt))

		rc = alloc_chrdev_region(&devt, MINOR(devt), 1, devinfo.name);

	else

		rc = register_chrdev_region(devt, 1, devinfo.name);

	if (rc) {

		printk(KERN_ERR "CUSE: failed to register chrdev region\n");

		goto err;

	}

	/* devt determined, create device */

	rc = -ENOMEM;

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);

	if (!dev)

		goto err_region;

	device_initialize(dev);

	dev_set_uevent_suppress(dev, 1);

	dev->class = cuse_class;

	dev->devt = devt;

	dev->release = cuse_gendev_release;

	dev_set_drvdata(dev, cc);

	dev_set_name(dev, "%s", devinfo.name);

	rc = device_add(dev);

	if (rc)

		goto err_device;

	/* register cdev */

	rc = -ENOMEM;

	cdev = cdev_alloc();

	if (!cdev)

		goto err_device;

	cdev->owner = THIS_MODULE;

	cdev->ops = &cuse_frontend_fops;

	rc = cdev_add(cdev, devt, 1);

	if (rc)

		goto err_cdev;

	cc->dev = dev;

	cc->cdev = cdev;

	/* make the device available */

	spin_lock(&cuse_lock);

	list_add(&cc->list, cuse_conntbl_head(devt));

	spin_unlock(&cuse_lock);

	/* announce device availability */

	dev_set_uevent_suppress(dev, 0);

	kobject_uevent(&dev->kobj, KOBJ_ADD);

out:

	__free_page(page);

	return;

err_cdev:

	cdev_del(cdev);

err_device:

	put_device(dev);

err_region:

	unregister_chrdev_region(devt, 1);

err:

	fc->conn_error = 1;

	goto out;

}

static int cuse_send_init(struct cuse_conn *cc)

{

	int rc;

	struct fuse_req *req;

	struct page *page;

	struct fuse_conn *fc = &cc->fc;

	struct cuse_init_in *arg;

	BUILD_BUG_ON(CUSE_INIT_INFO_MAX > PAGE_SIZE);

	req = fuse_get_req(fc);

	if (IS_ERR(req)) {

		rc = PTR_ERR(req);

		goto err;

	}

	rc = -ENOMEM;

	page = alloc_page(GFP_KERNEL | __GFP_ZERO);

	if (!page)

		goto err_put_req;

	arg = &req->misc.cuse_init_in;

	arg->major = FUSE_KERNEL_VERSION;

	arg->minor = FUSE_KERNEL_MINOR_VERSION;

	arg->flags |= CUSE_UNRESTRICTED_IOCTL;

	req->in.h.opcode = CUSE_INIT;

	req->in.numargs = 1;

	req->in.args[0].size = sizeof(struct cuse_init_in);

	req->in.args[0].value = arg;

	req->out.numargs = 2;

	req->out.args[0].size = sizeof(struct cuse_init_out);

	req->out.args[0].value = &req->misc.cuse_init_out;

	req->out.args[1].size = CUSE_INIT_INFO_MAX;

	req->out.argvar = 1;

	req->out.argpages = 1;

	req->pages[0] = page;

	req->num_pages = 1;

	req->end = cuse_process_init_reply;

	fuse_request_send_background(fc, req);

	return 0;

err_put_req:

	fuse_put_request(fc, req);

err:

	return rc;

}

static void cuse_fc_release(struct fuse_conn *fc)

{

	struct cuse_conn *cc = fc_to_cc(fc);

	kfree(cc);

}

/**

 * cuse_channel_open - open method for /dev/cuse

 * @inode: inode for /dev/cuse

 * @file: file struct being opened

 *

 * Userland CUSE server can create a CUSE device by opening /dev/cuse

 * and replying to the initilaization request kernel sends.  This

 * function is responsible for handling CUSE device initialization.

 * Because the fd opened by this function is used during

 * initialization, this function only creates cuse_conn and sends

 * init.  The rest is delegated to a kthread.

 *

 * RETURNS:

 * 0 on success, -errno on failure.

 */

static int cuse_channel_open(struct inode *inode, struct file *file)

{

	struct cuse_conn *cc;

	int rc;

	/* set up cuse_conn */

	cc = kzalloc(sizeof(*cc), GFP_KERNEL);

	if (!cc)

		return -ENOMEM;

	fuse_conn_init(&cc->fc);

	INIT_LIST_HEAD(&cc->list);

	cc->fc.release = cuse_fc_release;

	cc->fc.connected = 1;

	cc->fc.blocked = 0;

	rc = cuse_send_init(cc);

	if (rc) {

		fuse_conn_put(&cc->fc);

		return rc;

	}

	file->private_data = &cc->fc;	/* channel owns base reference to cc */

	return 0;

}

/**

 * cuse_channel_release - release method for /dev/cuse

 * @inode: inode for /dev/cuse

 * @file: file struct being closed

 *

 * Disconnect the channel, deregister CUSE device and initiate

 * destruction by putting the default reference.

 *

 * RETURNS:

 * 0 on success, -errno on failure.

 */

static int cuse_channel_release(struct inode *inode, struct file *file)

{

	struct cuse_conn *cc = fc_to_cc(file->private_data);

	int rc;

	/* remove from the conntbl, no more access from this point on */

	spin_lock(&cuse_lock);

	list_del_init(&cc->list);

	spin_unlock(&cuse_lock);

	/* remove device */

	if (cc->dev)

		device_unregister(cc->dev);

	if (cc->cdev) {

		unregister_chrdev_region(cc->cdev->dev, 1);

		cdev_del(cc->cdev);

	}

	/* kill connection and shutdown channel */

	fuse_conn_kill(&cc->fc);

	rc = fuse_dev_release(inode, file);	/* puts the base reference */

	return rc;

}

static struct file_operations cuse_channel_fops; /* initialized during init */

/**************************************************************************

 * Misc stuff and module initializatiion

 *

 * CUSE exports the same set of attributes to sysfs as fusectl.

 */

static ssize_t cuse_class_waiting_show(struct device *dev,

				       struct device_attribute *attr, char *buf)

{

	struct cuse_conn *cc = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", atomic_read(&cc->fc.num_waiting));

}

static ssize_t cuse_class_abort_store(struct device *dev,

				      struct device_attribute *attr,

				      const char *buf, size_t count)

{

	struct cuse_conn *cc = dev_get_drvdata(dev);

	fuse_abort_conn(&cc->fc);

	return count;

}

static struct device_attribute cuse_class_dev_attrs[] = {

	__ATTR(waiting, S_IFREG | 0400, cuse_class_waiting_show, NULL),

	__ATTR(abort, S_IFREG | 0200, NULL, cuse_class_abort_store),

	{ }

};

static struct miscdevice cuse_miscdev = {

	.minor		= MISC_DYNAMIC_MINOR,

	.name		= "cuse",

	.fops		= &cuse_channel_fops,

};

static int __init cuse_init(void)

{

	int i, rc;

	/* init conntbl */

	for (i = 0; i < CUSE_CONNTBL_LEN; i++)

		INIT_LIST_HEAD(&cuse_conntbl[i]);

	/* inherit and extend fuse_dev_operations */

	cuse_channel_fops		= fuse_dev_operations;

	cuse_channel_fops.owner		= THIS_MODULE;

	cuse_channel_fops.open		= cuse_channel_open;

	cuse_channel_fops.release	= cuse_channel_release;

	cuse_class = class_create(THIS_MODULE, "cuse");

	if (IS_ERR(cuse_class))

		return PTR_ERR(cuse_class);

	cuse_class->dev_attrs = cuse_class_dev_attrs;

	rc = misc_register(&cuse_miscdev);

	if (rc) {

		class_destroy(cuse_class);

		return rc;

	}

	return 0;

}

static void __exit cuse_exit(void)

{

	misc_deregister(&cuse_miscdev);

	class_destroy(cuse_class);

}

module_init(cuse_init);

module_exit(cuse_exit);

MODULE_AUTHOR("Tejun Heo <tj@kernel.org>");

MODULE_DESCRIPTION("Character device in Userspace");

MODULE_LICENSE("GPL");

		fuse_request_init(req);

	return req;

}

EXPORT_SYMBOL_GPL(fuse_request_alloc);

struct fuse_req *fuse_request_alloc_nofs(void)

{

	atomic_dec(&fc->num_waiting);

	return ERR_PTR(err);

}

EXPORT_SYMBOL_GPL(fuse_get_req);

/*

 * Return request in fuse_file->reserved_req.  However that may

			fuse_request_free(req);

	}

}

EXPORT_SYMBOL_GPL(fuse_put_request);

static unsigned len_args(unsigned numargs, struct fuse_arg *args)

{

			wake_up_all(&fc->blocked_waitq);

		}

		if (fc->num_background == FUSE_CONGESTION_THRESHOLD &&

		    fc->connected) {

		    fc->connected && fc->bdi_initialized) {

			clear_bdi_congested(&fc->bdi, READ);

			clear_bdi_congested(&fc->bdi, WRITE);

		}

	}

	spin_unlock(&fc->lock);

}

EXPORT_SYMBOL_GPL(fuse_request_send);

static void fuse_request_send_nowait_locked(struct fuse_conn *fc,

					    struct fuse_req *req)

	fc->num_background++;

	if (fc->num_background == FUSE_MAX_BACKGROUND)

		fc->blocked = 1;

	if (fc->num_background == FUSE_CONGESTION_THRESHOLD) {

	if (fc->num_background == FUSE_CONGESTION_THRESHOLD &&

	    fc->bdi_initialized) {

		set_bdi_congested(&fc->bdi, READ);

		set_bdi_congested(&fc->bdi, WRITE);

	}

	req->isreply = 1;

	fuse_request_send_nowait(fc, req);

}

EXPORT_SYMBOL_GPL(fuse_request_send_background);

/*

 * Called under fc->lock

	}

	spin_unlock(&fc->lock);

}

EXPORT_SYMBOL_GPL(fuse_abort_conn);

static int fuse_dev_release(struct inode *inode, struct file *file)

int fuse_dev_release(struct inode *inode, struct file *file)

{

	struct fuse_conn *fc = fuse_get_conn(file);

	if (fc) {

	return 0;

}

EXPORT_SYMBOL_GPL(fuse_dev_release);

static int fuse_dev_fasync(int fd, struct file *file, int on)

{