[deliverable/linux.git] / drivers / base / devtmpfs.c

/*
 * devtmpfs - kernel-maintained tmpfs-based /dev
 *
 * Copyright (C) 2009, Kay Sievers <kay.sievers@vrfy.org>
 *
 * During bootup, before any driver core device is registered,
 * devtmpfs, a tmpfs-based filesystem is created. Every driver-core
 * device which requests a device node, will add a node in this
 * filesystem.
 * By default, all devices are named after the name of the device,
 * owned by root and have a default mode of 0600. Subsystems can
 * overwrite the default setting if needed.
 */

#include <linux/kernel.h>
#include <linux/syscalls.h>
#include <linux/mount.h>
#include <linux/device.h>
#include <linux/genhd.h>
#include <linux/namei.h>
#include <linux/fs.h>
#include <linux/shmem_fs.h>
#include <linux/ramfs.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include "base.h"

static struct task_struct *thread;

#if defined CONFIG_DEVTMPFS_MOUNT
static int mount_dev = 1;
#else
static int mount_dev;
#endif

static DEFINE_SPINLOCK(req_lock);

static struct req {
	struct req *next;
	struct completion done;
	int err;
	const char *name;
	umode_t mode;	/* 0 => delete */
	kuid_t uid;
	kgid_t gid;
	struct device *dev;
} *requests;

static int __init mount_param(char *str)
{
	mount_dev = simple_strtoul(str, NULL, 0);
	return 1;
}
__setup("devtmpfs.mount=", mount_param);

static struct dentry *dev_mount(struct file_system_type *fs_type, int flags,
		      const char *dev_name, void *data)
{
#ifdef CONFIG_TMPFS
	return mount_single(fs_type, flags, data, shmem_fill_super);
#else
	return mount_single(fs_type, flags, data, ramfs_fill_super);
#endif
}

static struct file_system_type dev_fs_type = {
	.name = "devtmpfs",
	.mount = dev_mount,
	.kill_sb = kill_litter_super,
};

#ifdef CONFIG_BLOCK
static inline int is_blockdev(struct device *dev)
{
	return dev->class == &block_class;
}
#else
static inline int is_blockdev(struct device *dev) { return 0; }
#endif

int devtmpfs_create_node(struct device *dev)
{
	const char *tmp = NULL;
	struct req req;

	if (!thread)
		return 0;

	req.mode = 0;
	req.uid = GLOBAL_ROOT_UID;
	req.gid = GLOBAL_ROOT_GID;
	req.name = device_get_devnode(dev, &req.mode, &req.uid, &req.gid, &tmp);
	if (!req.name)
		return -ENOMEM;

	if (req.mode == 0)
		req.mode = 0600;
	if (is_blockdev(dev))
		req.mode |= S_IFBLK;
	else
		req.mode |= S_IFCHR;

	req.dev = dev;

	init_completion(&req.done);

	spin_lock(&req_lock);
	req.next = requests;
	requests = &req;
	spin_unlock(&req_lock);

	wake_up_process(thread);
	wait_for_completion(&req.done);

	kfree(tmp);

	return req.err;
}

int devtmpfs_delete_node(struct device *dev)
{
	const char *tmp = NULL;
	struct req req;

	if (!thread)
		return 0;

	req.name = device_get_devnode(dev, NULL, NULL, NULL, &tmp);
	if (!req.name)
		return -ENOMEM;

	req.mode = 0;
	req.dev = dev;

	init_completion(&req.done);

	spin_lock(&req_lock);
	req.next = requests;
	requests = &req;
	spin_unlock(&req_lock);

	wake_up_process(thread);
	wait_for_completion(&req.done);

	kfree(tmp);
	return req.err;
}

static int dev_mkdir(const char *name, umode_t mode)
{
	struct dentry *dentry;
	struct path path;
	int err;

	dentry = kern_path_create(AT_FDCWD, name, &path, LOOKUP_DIRECTORY);
	if (IS_ERR(dentry))
		return PTR_ERR(dentry);

	err = vfs_mkdir(d_inode(path.dentry), dentry, mode);
	if (!err)
		/* mark as kernel-created inode */
		d_inode(dentry)->i_private = &thread;
	done_path_create(&path, dentry);
	return err;
}

static int create_path(const char *nodepath)
{
	char *path;
	char *s;
	int err = 0;

	/* parent directories do not exist, create them */
	path = kstrdup(nodepath, GFP_KERNEL);
	if (!path)
		return -ENOMEM;

	s = path;
	for (;;) {
		s = strchr(s, '/');
		if (!s)
			break;
		s[0] = '\0';
		err = dev_mkdir(path, 0755);
		if (err && err != -EEXIST)
			break;
		s[0] = '/';
		s++;
	}
	kfree(path);
	return err;
}

static int handle_create(const char *nodename, umode_t mode, kuid_t uid,
			 kgid_t gid, struct device *dev)
{
	struct dentry *dentry;
	struct path path;
	int err;

	dentry = kern_path_create(AT_FDCWD, nodename, &path, 0);
	if (dentry == ERR_PTR(-ENOENT)) {
		create_path(nodename);
		dentry = kern_path_create(AT_FDCWD, nodename, &path, 0);
	}
	if (IS_ERR(dentry))
		return PTR_ERR(dentry);

	err = vfs_mknod(d_inode(path.dentry), dentry, mode, dev->devt);
	if (!err) {
		struct iattr newattrs;

		newattrs.ia_mode = mode;
		newattrs.ia_uid = uid;
		newattrs.ia_gid = gid;
		newattrs.ia_valid = ATTR_MODE|ATTR_UID|ATTR_GID;
		inode_lock(d_inode(dentry));
		notify_change(dentry, &newattrs, NULL);
		inode_unlock(d_inode(dentry));

		/* mark as kernel-created inode */
		d_inode(dentry)->i_private = &thread;
	}
	done_path_create(&path, dentry);
	return err;
}

static int dev_rmdir(const char *name)
{
	struct path parent;
	struct dentry *dentry;
	int err;

	dentry = kern_path_locked(name, &parent);
	if (IS_ERR(dentry))
		return PTR_ERR(dentry);
	if (d_really_is_positive(dentry)) {
		if (d_inode(dentry)->i_private == &thread)
			err = vfs_rmdir(d_inode(parent.dentry), dentry);
		else
			err = -EPERM;
	} else {
		err = -ENOENT;
	}
	dput(dentry);
	inode_unlock(d_inode(parent.dentry));
	path_put(&parent);
	return err;
}

static int delete_path(const char *nodepath)
{
	const char *path;
	int err = 0;

	path = kstrdup(nodepath, GFP_KERNEL);
	if (!path)
		return -ENOMEM;

	for (;;) {
		char *base;

		base = strrchr(path, '/');
		if (!base)
			break;
		base[0] = '\0';
		err = dev_rmdir(path);
		if (err)
			break;
	}

	kfree(path);
	return err;
}

static int dev_mynode(struct device *dev, struct inode *inode, struct kstat *stat)
{
	/* did we create it */
	if (inode->i_private != &thread)
		return 0;

	/* does the dev_t match */
	if (is_blockdev(dev)) {
		if (!S_ISBLK(stat->mode))
			return 0;
	} else {
		if (!S_ISCHR(stat->mode))
			return 0;
	}
	if (stat->rdev != dev->devt)
		return 0;

	/* ours */
	return 1;
}

static int handle_remove(const char *nodename, struct device *dev)
{
	struct path parent;
	struct dentry *dentry;
	int deleted = 0;
	int err;

	dentry = kern_path_locked(nodename, &parent);
	if (IS_ERR(dentry))
		return PTR_ERR(dentry);

	if (d_really_is_positive(dentry)) {
		struct kstat stat;
		struct path p = {.mnt = parent.mnt, .dentry = dentry};
		err = vfs_getattr(&p, &stat);
		if (!err && dev_mynode(dev, d_inode(dentry), &stat)) {
			struct iattr newattrs;
			/*
			 * before unlinking this node, reset permissions
			 * of possible references like hardlinks
			 */
			newattrs.ia_uid = GLOBAL_ROOT_UID;
			newattrs.ia_gid = GLOBAL_ROOT_GID;
			newattrs.ia_mode = stat.mode & ~0777;
			newattrs.ia_valid =
				ATTR_UID|ATTR_GID|ATTR_MODE;
			inode_lock(d_inode(dentry));
			notify_change(dentry, &newattrs, NULL);
			inode_unlock(d_inode(dentry));
			err = vfs_unlink(d_inode(parent.dentry), dentry, NULL);
			if (!err || err == -ENOENT)
				deleted = 1;
		}
	} else {
		err = -ENOENT;
	}
	dput(dentry);
	inode_unlock(d_inode(parent.dentry));

	path_put(&parent);
	if (deleted && strchr(nodename, '/'))
		delete_path(nodename);
	return err;
}

/*
 * If configured, or requested by the commandline, devtmpfs will be
 * auto-mounted after the kernel mounted the root filesystem.
 */
int devtmpfs_mount(const char *mntdir)
{
	int err;

	if (!mount_dev)
		return 0;

	if (!thread)
		return 0;

	err = sys_mount("devtmpfs", (char *)mntdir, "devtmpfs", MS_SILENT, NULL);
	if (err)
		printk(KERN_INFO "devtmpfs: error mounting %i\n", err);
	else
		printk(KERN_INFO "devtmpfs: mounted\n");
	return err;
}

static DECLARE_COMPLETION(setup_done);

static int handle(const char *name, umode_t mode, kuid_t uid, kgid_t gid,
		  struct device *dev)
{
	if (mode)
		return handle_create(name, mode, uid, gid, dev);
	else
		return handle_remove(name, dev);
}

static int devtmpfsd(void *p)
{
	char options[] = "mode=0755";
	int *err = p;
	*err = sys_unshare(CLONE_NEWNS);
	if (*err)
		goto out;
	*err = sys_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, options);
	if (*err)
		goto out;
	sys_chdir("/.."); /* will traverse into overmounted root */
	sys_chroot(".");
	complete(&setup_done);
	while (1) {
		spin_lock(&req_lock);
		while (requests) {
			struct req *req = requests;
			requests = NULL;
			spin_unlock(&req_lock);
			while (req) {
				struct req *next = req->next;
				req->err = handle(req->name, req->mode,
						  req->uid, req->gid, req->dev);
				complete(&req->done);
				req = next;
			}
			spin_lock(&req_lock);
		}
		__set_current_state(TASK_INTERRUPTIBLE);
		spin_unlock(&req_lock);
		schedule();
	}
	return 0;
out:
	complete(&setup_done);
	return *err;
}

/*
 * Create devtmpfs instance, driver-core devices will add their device
 * nodes here.
 */
int __init devtmpfs_init(void)
{
	int err = register_filesystem(&dev_fs_type);
	if (err) {
		printk(KERN_ERR "devtmpfs: unable to register devtmpfs "
		       "type %i\n", err);
		return err;
	}

	thread = kthread_run(devtmpfsd, &err, "kdevtmpfs");
	if (!IS_ERR(thread)) {
		wait_for_completion(&setup_done);
	} else {
		err = PTR_ERR(thread);
		thread = NULL;
	}

	if (err) {
		printk(KERN_ERR "devtmpfs: unable to create devtmpfs %i\n", err);
		unregister_filesystem(&dev_fs_type);
		return err;
	}

	printk(KERN_INFO "devtmpfs: initialized\n");
	return 0;
}
Commit	Line	Data
2b2af54a KS	1	/*
	2	* devtmpfs - kernel-maintained tmpfs-based /dev
	3	*
	4	* Copyright (C) 2009, Kay Sievers <kay.sievers@vrfy.org>
	5	*
	6	* During bootup, before any driver core device is registered,
	7	* devtmpfs, a tmpfs-based filesystem is created. Every driver-core
	8	* device which requests a device node, will add a node in this
e454cea2	9	* filesystem.
02fbe5e6 PK	10	* By default, all devices are named after the name of the device,
	11	* owned by root and have a default mode of 0600. Subsystems can
	12	* overwrite the default setting if needed.
2b2af54a KS	13	*/
	14
	15	#include <linux/kernel.h>
	16	#include <linux/syscalls.h>
	17	#include <linux/mount.h>
	18	#include <linux/device.h>
	19	#include <linux/genhd.h>
	20	#include <linux/namei.h>
	21	#include <linux/fs.h>
	22	#include <linux/shmem_fs.h>
da5e4ef7	23	#include <linux/ramfs.h>
e454cea2	24	#include <linux/sched.h>
5a0e3ad6	25	#include <linux/slab.h>
2780f1ff	26	#include <linux/kthread.h>
c3a30420	27	#include "base.h"
2b2af54a	28
2780f1ff	29	static struct task_struct *thread;
2b2af54a KS	30
2b2af54a KS	31	#if defined CONFIG_DEVTMPFS_MOUNT
fc14f2fe	32	static int mount_dev = 1;
2b2af54a	33	#else
fc14f2fe	34	static int mount_dev;
2b2af54a KS	35	#endif
2b2af54a KS	36
2780f1ff AV	37	static DEFINE_SPINLOCK(req_lock);
	38
	39	static struct req {
	40	struct req *next;
	41	struct completion done;
	42	int err;
	43	const char *name;
2c9ede55	44	umode_t mode; /* 0 => delete */
4e4098a3 GKH	45	kuid_t uid;
4e4098a3 GKH	46	kgid_t gid;
2780f1ff AV	47	struct device *dev;
2780f1ff AV	48	} *requests;
ed413ae6	49
2b2af54a KS	50	static int __init mount_param(char *str)
2b2af54a KS	51	{
fc14f2fe	52	mount_dev = simple_strtoul(str, NULL, 0);
2b2af54a KS	53	return 1;
	54	}
	55	__setup("devtmpfs.mount=", mount_param);
	56
fc14f2fe AV	57	static struct dentry dev_mount(struct file_system_type fs_type, int flags,
fc14f2fe AV	58	const char dev_name, void data)
2b2af54a	59	{
da5e4ef7	60	#ifdef CONFIG_TMPFS
fc14f2fe	61	return mount_single(fs_type, flags, data, shmem_fill_super);
da5e4ef7	62	#else
fc14f2fe	63	return mount_single(fs_type, flags, data, ramfs_fill_super);
da5e4ef7	64	#endif
2b2af54a KS	65	}
	66
	67	static struct file_system_type dev_fs_type = {
	68	.name = "devtmpfs",
fc14f2fe	69	.mount = dev_mount,
2b2af54a KS	70	.kill_sb = kill_litter_super,
	71	};
	72
	73	#ifdef CONFIG_BLOCK
	74	static inline int is_blockdev(struct device *dev)
	75	{
	76	return dev->class == &block_class;
	77	}
	78	#else
	79	static inline int is_blockdev(struct device *dev) { return 0; }
	80	#endif
	81
2780f1ff AV	82	int devtmpfs_create_node(struct device *dev)
	83	{
	84	const char *tmp = NULL;
	85	struct req req;
	86
	87	if (!thread)
	88	return 0;
	89
	90	req.mode = 0;
4e4098a3 GKH	91	req.uid = GLOBAL_ROOT_UID;
4e4098a3 GKH	92	req.gid = GLOBAL_ROOT_GID;
3c2670e6	93	req.name = device_get_devnode(dev, &req.mode, &req.uid, &req.gid, &tmp);
2780f1ff AV	94	if (!req.name)
	95	return -ENOMEM;
	96
	97	if (req.mode == 0)
	98	req.mode = 0600;
	99	if (is_blockdev(dev))
	100	req.mode \|= S_IFBLK;
	101	else
	102	req.mode \|= S_IFCHR;
	103
	104	req.dev = dev;
	105
	106	init_completion(&req.done);
	107
	108	spin_lock(&req_lock);
	109	req.next = requests;
	110	requests = &req;
	111	spin_unlock(&req_lock);
	112
	113	wake_up_process(thread);
	114	wait_for_completion(&req.done);
	115
	116	kfree(tmp);
	117
	118	return req.err;
	119	}
	120
	121	int devtmpfs_delete_node(struct device *dev)
	122	{
	123	const char *tmp = NULL;
	124	struct req req;
	125
	126	if (!thread)
	127	return 0;
	128
3c2670e6	129	req.name = device_get_devnode(dev, NULL, NULL, NULL, &tmp);
2780f1ff AV	130	if (!req.name)
	131	return -ENOMEM;
	132
	133	req.mode = 0;
	134	req.dev = dev;
	135
	136	init_completion(&req.done);
	137
	138	spin_lock(&req_lock);
	139	req.next = requests;
	140	requests = &req;
	141	spin_unlock(&req_lock);
	142
	143	wake_up_process(thread);
	144	wait_for_completion(&req.done);
	145
	146	kfree(tmp);
	147	return req.err;
	148	}
	149
fbd48a69	150	static int dev_mkdir(const char *name, umode_t mode)
2b2af54a	151	{
2b2af54a	152	struct dentry *dentry;
69753a0f	153	struct path path;
2b2af54a KS	154	int err;
2b2af54a KS	155
1ac12b4b	156	dentry = kern_path_create(AT_FDCWD, name, &path, LOOKUP_DIRECTORY);
69753a0f AV	157	if (IS_ERR(dentry))
	158	return PTR_ERR(dentry);
	159
75c3cfa8	160	err = vfs_mkdir(d_inode(path.dentry), dentry, mode);
69753a0f AV	161	if (!err)
69753a0f AV	162	/* mark as kernel-created inode */
75c3cfa8	163	d_inode(dentry)->i_private = &thread;
921a1650	164	done_path_create(&path, dentry);
2b2af54a KS	165	return err;
	166	}
	167
	168	static int create_path(const char *nodepath)
	169	{
5da4e689 AV	170	char *path;
5da4e689 AV	171	char *s;
9d108d25	172	int err = 0;
2b2af54a	173
5da4e689 AV	174	/* parent directories do not exist, create them */
	175	path = kstrdup(nodepath, GFP_KERNEL);
	176	if (!path)
	177	return -ENOMEM;
	178
	179	s = path;
	180	for (;;) {
	181	s = strchr(s, '/');
	182	if (!s)
	183	break;
	184	s[0] = '\0';
	185	err = dev_mkdir(path, 0755);
	186	if (err && err != -EEXIST)
	187	break;
	188	s[0] = '/';
	189	s++;
2b2af54a	190	}
5da4e689	191	kfree(path);
2b2af54a KS	192	return err;
	193	}
	194
4e4098a3 GKH	195	static int handle_create(const char *nodename, umode_t mode, kuid_t uid,
4e4098a3 GKH	196	kgid_t gid, struct device *dev)
2b2af54a	197	{
2b2af54a	198	struct dentry *dentry;
69753a0f	199	struct path path;
2b2af54a KS	200	int err;
2b2af54a KS	201
69753a0f AV	202	dentry = kern_path_create(AT_FDCWD, nodename, &path, 0);
69753a0f AV	203	if (dentry == ERR_PTR(-ENOENT)) {
2b2af54a	204	create_path(nodename);
69753a0f	205	dentry = kern_path_create(AT_FDCWD, nodename, &path, 0);
2b2af54a	206	}
69753a0f AV	207	if (IS_ERR(dentry))
	208	return PTR_ERR(dentry);
	209
75c3cfa8	210	err = vfs_mknod(d_inode(path.dentry), dentry, mode, dev->devt);
69753a0f AV	211	if (!err) {
	212	struct iattr newattrs;
	213
69753a0f	214	newattrs.ia_mode = mode;
4e4098a3 GKH	215	newattrs.ia_uid = uid;
4e4098a3 GKH	216	newattrs.ia_gid = gid;
3c2670e6	217	newattrs.ia_valid = ATTR_MODE\|ATTR_UID\|ATTR_GID;
5955102c	218	inode_lock(d_inode(dentry));
27ac0ffe	219	notify_change(dentry, &newattrs, NULL);
5955102c	220	inode_unlock(d_inode(dentry));
69753a0f AV	221
69753a0f AV	222	/* mark as kernel-created inode */
75c3cfa8	223	d_inode(dentry)->i_private = &thread;
2b2af54a	224	}
921a1650	225	done_path_create(&path, dentry);
2b2af54a KS	226	return err;
	227	}
	228
	229	static int dev_rmdir(const char *name)
	230	{
79714f72	231	struct path parent;
2b2af54a KS	232	struct dentry *dentry;
	233	int err;
	234
79714f72 AV	235	dentry = kern_path_locked(name, &parent);
	236	if (IS_ERR(dentry))
	237	return PTR_ERR(dentry);
75c3cfa8 DH	238	if (d_really_is_positive(dentry)) {
	239	if (d_inode(dentry)->i_private == &thread)
	240	err = vfs_rmdir(d_inode(parent.dentry), dentry);
79714f72 AV	241	else
79714f72 AV	242	err = -EPERM;
2b2af54a	243	} else {
79714f72	244	err = -ENOENT;
2b2af54a	245	}
79714f72	246	dput(dentry);
5955102c	247	inode_unlock(d_inode(parent.dentry));
79714f72	248	path_put(&parent);
2b2af54a KS	249	return err;
	250	}
	251
	252	static int delete_path(const char *nodepath)
	253	{
	254	const char *path;
	255	int err = 0;
	256
	257	path = kstrdup(nodepath, GFP_KERNEL);
	258	if (!path)
	259	return -ENOMEM;
	260
ed413ae6	261	for (;;) {
2b2af54a KS	262	char *base;
	263
	264	base = strrchr(path, '/');
	265	if (!base)
	266	break;
	267	base[0] = '\0';
	268	err = dev_rmdir(path);
	269	if (err)
	270	break;
	271	}
	272
	273	kfree(path);
	274	return err;
	275	}
	276
	277	static int dev_mynode(struct device dev, struct inode inode, struct kstat *stat)
	278	{
	279	/* did we create it */
2780f1ff	280	if (inode->i_private != &thread)
2b2af54a KS	281	return 0;
	282
	283	/* does the dev_t match */
	284	if (is_blockdev(dev)) {
	285	if (!S_ISBLK(stat->mode))
	286	return 0;
	287	} else {
	288	if (!S_ISCHR(stat->mode))
	289	return 0;
	290	}
	291	if (stat->rdev != dev->devt)
	292	return 0;
	293
	294	/* ours */
	295	return 1;
	296	}
	297
2780f1ff	298	static int handle_remove(const char nodename, struct device dev)
2b2af54a	299	{
79714f72	300	struct path parent;
2b2af54a	301	struct dentry *dentry;
fbde7c61	302	int deleted = 0;
2b2af54a KS	303	int err;
2b2af54a KS	304
79714f72 AV	305	dentry = kern_path_locked(nodename, &parent);
	306	if (IS_ERR(dentry))
	307	return PTR_ERR(dentry);
	308
75c3cfa8	309	if (d_really_is_positive(dentry)) {
79714f72	310	struct kstat stat;
3dadecce AV	311	struct path p = {.mnt = parent.mnt, .dentry = dentry};
3dadecce AV	312	err = vfs_getattr(&p, &stat);
75c3cfa8	313	if (!err && dev_mynode(dev, d_inode(dentry), &stat)) {
79714f72 AV	314	struct iattr newattrs;
	315	/*
	316	* before unlinking this node, reset permissions
	317	* of possible references like hardlinks
	318	*/
91fa2cca EB	319	newattrs.ia_uid = GLOBAL_ROOT_UID;
91fa2cca EB	320	newattrs.ia_gid = GLOBAL_ROOT_GID;
79714f72 AV	321	newattrs.ia_mode = stat.mode & ~0777;
	322	newattrs.ia_valid =
	323	ATTR_UID\|ATTR_GID\|ATTR_MODE;
5955102c	324	inode_lock(d_inode(dentry));
27ac0ffe	325	notify_change(dentry, &newattrs, NULL);
5955102c	326	inode_unlock(d_inode(dentry));
75c3cfa8	327	err = vfs_unlink(d_inode(parent.dentry), dentry, NULL);
79714f72 AV	328	if (!err \|\| err == -ENOENT)
79714f72 AV	329	deleted = 1;
2b2af54a	330	}
2b2af54a	331	} else {
79714f72	332	err = -ENOENT;
2b2af54a	333	}
79714f72	334	dput(dentry);
5955102c	335	inode_unlock(d_inode(parent.dentry));
2b2af54a	336
79714f72	337	path_put(&parent);
2b2af54a KS	338	if (deleted && strchr(nodename, '/'))
2b2af54a KS	339	delete_path(nodename);
2b2af54a KS	340	return err;
	341	}
	342
	343	/*
	344	* If configured, or requested by the commandline, devtmpfs will be
	345	* auto-mounted after the kernel mounted the root filesystem.
	346	*/
073120cc	347	int devtmpfs_mount(const char *mntdir)
2b2af54a	348	{
2b2af54a KS	349	int err;
2b2af54a KS	350
fc14f2fe	351	if (!mount_dev)
2b2af54a KS	352	return 0;
2b2af54a KS	353
2780f1ff	354	if (!thread)
2b2af54a KS	355	return 0;
2b2af54a KS	356
073120cc	357	err = sys_mount("devtmpfs", (char *)mntdir, "devtmpfs", MS_SILENT, NULL);
2b2af54a KS	358	if (err)
	359	printk(KERN_INFO "devtmpfs: error mounting %i\n", err);
	360	else
	361	printk(KERN_INFO "devtmpfs: mounted\n");
2b2af54a KS	362	return err;
	363	}
	364
f9e0b159	365	static DECLARE_COMPLETION(setup_done);
2780f1ff	366
4e4098a3	367	static int handle(const char *name, umode_t mode, kuid_t uid, kgid_t gid,
3c2670e6	368	struct device *dev)
2780f1ff AV	369	{
2780f1ff AV	370	if (mode)
3c2670e6	371	return handle_create(name, mode, uid, gid, dev);
2780f1ff AV	372	else
	373	return handle_remove(name, dev);
	374	}
	375
	376	static int devtmpfsd(void *p)
	377	{
	378	char options[] = "mode=0755";
	379	int *err = p;
	380	*err = sys_unshare(CLONE_NEWNS);
	381	if (*err)
	382	goto out;
	383	*err = sys_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, options);
	384	if (*err)
	385	goto out;
	386	sys_chdir("/.."); /* will traverse into overmounted root */
	387	sys_chroot(".");
	388	complete(&setup_done);
	389	while (1) {
	390	spin_lock(&req_lock);
	391	while (requests) {
	392	struct req *req = requests;
	393	requests = NULL;
	394	spin_unlock(&req_lock);
	395	while (req) {
e13889ba	396	struct req *next = req->next;
3c2670e6 KS	397	req->err = handle(req->name, req->mode,
3c2670e6 KS	398	req->uid, req->gid, req->dev);
2780f1ff	399	complete(&req->done);
e13889ba	400	req = next;
2780f1ff AV	401	}
	402	spin_lock(&req_lock);
	403	}
65e6757b	404	__set_current_state(TASK_INTERRUPTIBLE);
2780f1ff AV	405	spin_unlock(&req_lock);
2780f1ff AV	406	schedule();
2780f1ff AV	407	}
	408	return 0;
	409	out:
	410	complete(&setup_done);
	411	return *err;
	412	}
	413
2b2af54a KS	414	/*
	415	* Create devtmpfs instance, driver-core devices will add their device
	416	* nodes here.
	417	*/
	418	int __init devtmpfs_init(void)
	419	{
2780f1ff	420	int err = register_filesystem(&dev_fs_type);
2b2af54a KS	421	if (err) {
	422	printk(KERN_ERR "devtmpfs: unable to register devtmpfs "
	423	"type %i\n", err);
	424	return err;
	425	}
	426
2780f1ff AV	427	thread = kthread_run(devtmpfsd, &err, "kdevtmpfs");
	428	if (!IS_ERR(thread)) {
	429	wait_for_completion(&setup_done);
	430	} else {
	431	err = PTR_ERR(thread);
	432	thread = NULL;
	433	}
	434
	435	if (err) {
2b2af54a KS	436	printk(KERN_ERR "devtmpfs: unable to create devtmpfs %i\n", err);
	437	unregister_filesystem(&dev_fs_type);
	438	return err;
	439	}
2b2af54a KS	440
	441	printk(KERN_INFO "devtmpfs: initialized\n");
	442	return 0;
	443	}