[net-next-2.6.git] / drivers / isdn / capi / capifs.c

/* $Id: capifs.c,v 1.1.2.3 2004/01/16 21:09:26 keil Exp $
 * 
 * Copyright 2000 by Carsten Paeth <calle@calle.de>
 *
 * Heavily based on devpts filesystem from H. Peter Anvin
 * 
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 */

#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/ctype.h>
#include <linux/sched.h>	/* current */

#include "capifs.h"

MODULE_DESCRIPTION("CAPI4Linux: /dev/capi/ filesystem");
MODULE_AUTHOR("Carsten Paeth");
MODULE_LICENSE("GPL");

/* ------------------------------------------------------------------ */

#define CAPIFS_SUPER_MAGIC (('C'<<8)|'N')

static struct vfsmount *capifs_mnt;
static int capifs_mnt_count;

static struct {
	int setuid;
	int setgid;
	uid_t   uid;
	gid_t   gid;
	umode_t mode;
} config = {.mode = 0600};

/* ------------------------------------------------------------------ */

static int capifs_remount(struct super_block *s, int *flags, char *data)
{
	int setuid = 0;
	int setgid = 0;
	uid_t uid = 0;
	gid_t gid = 0;
	umode_t mode = 0600;
	char *this_char;
	char *new_opt = kstrdup(data, GFP_KERNEL);

	this_char = NULL;
	while ((this_char = strsep(&data, ",")) != NULL) {
		int n;
		char dummy;
		if (!*this_char)
			continue;
		if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) {
			setuid = 1;
			uid = n;
		} else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) {
			setgid = 1;
			gid = n;
		} else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1)
			mode = n & ~S_IFMT;
		else {
			kfree(new_opt);
			printk("capifs: called with bogus options\n");
			return -EINVAL;
		}
	}

	mutex_lock(&s->s_root->d_inode->i_mutex);

	replace_mount_options(s, new_opt);
	config.setuid  = setuid;
	config.setgid  = setgid;
	config.uid     = uid;
	config.gid     = gid;
	config.mode    = mode;

	mutex_unlock(&s->s_root->d_inode->i_mutex);

	return 0;
}

static const struct super_operations capifs_sops =
{
	.statfs		= simple_statfs,
	.remount_fs	= capifs_remount,
	.show_options	= generic_show_options,
};


static int
capifs_fill_super(struct super_block *s, void *data, int silent)
{
	struct inode * inode;

	s->s_blocksize = 1024;
	s->s_blocksize_bits = 10;
	s->s_magic = CAPIFS_SUPER_MAGIC;
	s->s_op = &capifs_sops;
	s->s_time_gran = 1;

	inode = new_inode(s);
	if (!inode)
		goto fail;
	inode->i_ino = 1;
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
	inode->i_op = &simple_dir_inode_operations;
	inode->i_fop = &simple_dir_operations;
	inode->i_nlink = 2;

	s->s_root = d_alloc_root(inode);
	if (s->s_root)
		return 0;
	
	printk("capifs: get root dentry failed\n");
	iput(inode);
fail:
	return -ENOMEM;
}

static int capifs_get_sb(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
	return get_sb_single(fs_type, flags, data, capifs_fill_super, mnt);
}

static struct file_system_type capifs_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "capifs",
	.get_sb		= capifs_get_sb,
	.kill_sb	= kill_anon_super,
};

static struct dentry *new_ncci(unsigned int number, dev_t device)
{
	struct super_block *s = capifs_mnt->mnt_sb;
	struct dentry *root = s->s_root;
	struct dentry *dentry;
	struct inode *inode;
	char name[10];
	int namelen;

	mutex_lock(&root->d_inode->i_mutex);

	namelen = sprintf(name, "%d", number);
	dentry = lookup_one_len(name, root, namelen);
	if (IS_ERR(dentry)) {
		dentry = NULL;
		goto unlock_out;
	}

	if (dentry->d_inode) {
		dput(dentry);
		dentry = NULL;
		goto unlock_out;
	}

	inode = new_inode(s);
	if (!inode) {
		dput(dentry);
		dentry = NULL;
		goto unlock_out;
	}

	/* config contents is protected by root's i_mutex */
	inode->i_uid = config.setuid ? config.uid : current_fsuid();
	inode->i_gid = config.setgid ? config.gid : current_fsgid();
	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	inode->i_ino = number + 2;
	init_special_inode(inode, S_IFCHR|config.mode, device);

	d_instantiate(dentry, inode);
	dget(dentry);

unlock_out:
	mutex_unlock(&root->d_inode->i_mutex);

	return dentry;
}

struct dentry *capifs_new_ncci(unsigned int number, dev_t device)
{
	struct dentry *dentry;

	if (simple_pin_fs(&capifs_fs_type, &capifs_mnt, &capifs_mnt_count) < 0)
		return NULL;

	dentry = new_ncci(number, device);
	if (!dentry)
		simple_release_fs(&capifs_mnt, &capifs_mnt_count);

	return dentry;
}

void capifs_free_ncci(struct dentry *dentry)
{
	struct dentry *root = capifs_mnt->mnt_sb->s_root;
	struct inode *inode;

	if (!dentry)
		return;

	mutex_lock(&root->d_inode->i_mutex);

	inode = dentry->d_inode;
	if (inode) {
		drop_nlink(inode);
		d_delete(dentry);
		dput(dentry);
	}
	dput(dentry);

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

	simple_release_fs(&capifs_mnt, &capifs_mnt_count);
}

static int __init capifs_init(void)
{
	return register_filesystem(&capifs_fs_type);
}

static void __exit capifs_exit(void)
{
	unregister_filesystem(&capifs_fs_type);
}

EXPORT_SYMBOL(capifs_new_ncci);
EXPORT_SYMBOL(capifs_free_ncci);

module_init(capifs_init);
module_exit(capifs_exit);
Commit	Line	Data
1da177e4 LT	1	/* $Id: capifs.c,v 1.1.2.3 2004/01/16 21:09:26 keil Exp $
	2	*
	3	* Copyright 2000 by Carsten Paeth <calle@calle.de>
	4	*
	5	* Heavily based on devpts filesystem from H. Peter Anvin
	6	*
	7	* This software may be used and distributed according to the terms
	8	* of the GNU General Public License, incorporated herein by reference.
	9	*
	10	*/
	11
	12	#include <linux/fs.h>
	13	#include <linux/mount.h>
	14	#include <linux/namei.h>
	15	#include <linux/module.h>
	16	#include <linux/init.h>
	17	#include <linux/ctype.h>
4e57b681	18	#include <linux/sched.h> /* current */
1da177e4	19
6e21bd9a AB	20	#include "capifs.h"
6e21bd9a AB	21
1da177e4 LT	22	MODULE_DESCRIPTION("CAPI4Linux: /dev/capi/ filesystem");
	23	MODULE_AUTHOR("Carsten Paeth");
	24	MODULE_LICENSE("GPL");
	25
	26	/* ------------------------------------------------------------------ */
	27
1da177e4 LT	28	#define CAPIFS_SUPER_MAGIC (('C'<<8)\|'N')
	29
	30	static struct vfsmount *capifs_mnt;
e11e7ac1	31	static int capifs_mnt_count;
1da177e4 LT	32
	33	static struct {
	34	int setuid;
	35	int setgid;
	36	uid_t uid;
	37	gid_t gid;
	38	umode_t mode;
	39	} config = {.mode = 0600};
	40
	41	/* ------------------------------------------------------------------ */
	42
	43	static int capifs_remount(struct super_block s, int flags, char *data)
	44	{
	45	int setuid = 0;
	46	int setgid = 0;
	47	uid_t uid = 0;
	48	gid_t gid = 0;
	49	umode_t mode = 0600;
	50	char *this_char;
e55e212c	51	char *new_opt = kstrdup(data, GFP_KERNEL);
1da177e4 LT	52
	53	this_char = NULL;
	54	while ((this_char = strsep(&data, ",")) != NULL) {
	55	int n;
	56	char dummy;
	57	if (!*this_char)
	58	continue;
	59	if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) {
	60	setuid = 1;
	61	uid = n;
	62	} else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) {
	63	setgid = 1;
	64	gid = n;
	65	} else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1)
	66	mode = n & ~S_IFMT;
	67	else {
c24e9b3f	68	kfree(new_opt);
1da177e4 LT	69	printk("capifs: called with bogus options\n");
	70	return -EINVAL;
	71	}
	72	}
e55e212c	73
b0c4f322	74	mutex_lock(&s->s_root->d_inode->i_mutex);
e55e212c	75
b0c4f322	76	replace_mount_options(s, new_opt);
1da177e4 LT	77	config.setuid = setuid;
	78	config.setgid = setgid;
	79	config.uid = uid;
	80	config.gid = gid;
	81	config.mode = mode;
e55e212c	82
b0c4f322 AV	83	mutex_unlock(&s->s_root->d_inode->i_mutex);
b0c4f322 AV	84
1da177e4 LT	85	return 0;
	86	}
	87
b87221de	88	static const struct super_operations capifs_sops =
1da177e4 LT	89	{
	90	.statfs = simple_statfs,
	91	.remount_fs = capifs_remount,
e55e212c	92	.show_options = generic_show_options,
1da177e4 LT	93	};
	94
	95
	96	static int
	97	capifs_fill_super(struct super_block s, void data, int silent)
	98	{
	99	struct inode * inode;
	100
	101	s->s_blocksize = 1024;
	102	s->s_blocksize_bits = 10;
	103	s->s_magic = CAPIFS_SUPER_MAGIC;
	104	s->s_op = &capifs_sops;
	105	s->s_time_gran = 1;
	106
	107	inode = new_inode(s);
	108	if (!inode)
	109	goto fail;
	110	inode->i_ino = 1;
	111	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1da177e4 LT	112	inode->i_mode = S_IFDIR \| S_IRUGO \| S_IXUGO \| S_IWUSR;
	113	inode->i_op = &simple_dir_inode_operations;
	114	inode->i_fop = &simple_dir_operations;
	115	inode->i_nlink = 2;
	116
07ad603a	117	s->s_root = d_alloc_root(inode);
1da177e4 LT	118	if (s->s_root)
	119	return 0;
	120
	121	printk("capifs: get root dentry failed\n");
	122	iput(inode);
	123	fail:
	124	return -ENOMEM;
	125	}
	126
454e2398 DH	127	static int capifs_get_sb(struct file_system_type *fs_type,
454e2398 DH	128	int flags, const char dev_name, void data, struct vfsmount *mnt)
1da177e4	129	{
454e2398	130	return get_sb_single(fs_type, flags, data, capifs_fill_super, mnt);
1da177e4 LT	131	}
	132
	133	static struct file_system_type capifs_fs_type = {
	134	.owner = THIS_MODULE,
	135	.name = "capifs",
	136	.get_sb = capifs_get_sb,
	137	.kill_sb = kill_anon_super,
	138	};
	139
e11e7ac1	140	static struct dentry *new_ncci(unsigned int number, dev_t device)
1da177e4	141	{
07ad603a JK	142	struct super_block *s = capifs_mnt->mnt_sb;
07ad603a JK	143	struct dentry *root = s->s_root;
1da177e4	144	struct dentry *dentry;
c947862f	145	struct inode *inode;
90926f0e JK	146	char name[10];
90926f0e JK	147	int namelen;
b0c4f322	148
07ad603a	149	mutex_lock(&root->d_inode->i_mutex);
90926f0e JK	150
90926f0e JK	151	namelen = sprintf(name, "%d", number);
07ad603a	152	dentry = lookup_one_len(name, root, namelen);
90926f0e JK	153	if (IS_ERR(dentry)) {
90926f0e JK	154	dentry = NULL;
c947862f	155	goto unlock_out;
90926f0e	156	}
c947862f JK	157
	158	if (dentry->d_inode) {
	159	dput(dentry);
90926f0e	160	dentry = NULL;
c947862f JK	161	goto unlock_out;
	162	}
	163
07ad603a	164	inode = new_inode(s);
c947862f JK	165	if (!inode) {
c947862f JK	166	dput(dentry);
90926f0e	167	dentry = NULL;
c947862f JK	168	goto unlock_out;
c947862f JK	169	}
b0c4f322 AV	170
b0c4f322 AV	171	/* config contents is protected by root's i_mutex */
0e164b68 DH	172	inode->i_uid = config.setuid ? config.uid : current_fsuid();
0e164b68 DH	173	inode->i_gid = config.setgid ? config.gid : current_fsgid();
1da177e4	174	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
c947862f	175	inode->i_ino = number + 2;
1da177e4	176	init_special_inode(inode, S_IFCHR\|config.mode, device);
1da177e4	177
c947862f	178	d_instantiate(dentry, inode);
90926f0e	179	dget(dentry);
c947862f JK	180
c947862f JK	181	unlock_out:
07ad603a	182	mutex_unlock(&root->d_inode->i_mutex);
90926f0e JK	183
90926f0e JK	184	return dentry;
1da177e4 LT	185	}
1da177e4 LT	186
e11e7ac1 JK	187	struct dentry *capifs_new_ncci(unsigned int number, dev_t device)
	188	{
	189	struct dentry *dentry;
	190
	191	if (simple_pin_fs(&capifs_fs_type, &capifs_mnt, &capifs_mnt_count) < 0)
	192	return NULL;
	193
	194	dentry = new_ncci(number, device);
	195	if (!dentry)
	196	simple_release_fs(&capifs_mnt, &capifs_mnt_count);
	197
	198	return dentry;
	199	}
	200
90926f0e	201	void capifs_free_ncci(struct dentry *dentry)
1da177e4	202	{
07ad603a	203	struct dentry *root = capifs_mnt->mnt_sb->s_root;
90926f0e JK	204	struct inode *inode;
	205
	206	if (!dentry)
	207	return;
	208
07ad603a	209	mutex_lock(&root->d_inode->i_mutex);
90926f0e JK	210
	211	inode = dentry->d_inode;
	212	if (inode) {
	213	drop_nlink(inode);
	214	d_delete(dentry);
1da177e4 LT	215	dput(dentry);
1da177e4 LT	216	}
90926f0e JK	217	dput(dentry);
90926f0e JK	218
07ad603a	219	mutex_unlock(&root->d_inode->i_mutex);
e11e7ac1 JK	220
e11e7ac1 JK	221	simple_release_fs(&capifs_mnt, &capifs_mnt_count);
1da177e4 LT	222	}
	223
	224	static int __init capifs_init(void)
	225	{
88549d6b	226	return register_filesystem(&capifs_fs_type);
1da177e4 LT	227	}
	228
	229	static void __exit capifs_exit(void)
	230	{
	231	unregister_filesystem(&capifs_fs_type);
1da177e4 LT	232	}
	233
	234	EXPORT_SYMBOL(capifs_new_ncci);
	235	EXPORT_SYMBOL(capifs_free_ncci);
	236
	237	module_init(capifs_init);
	238	module_exit(capifs_exit);