[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/slab.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 struct dentry *capifs_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *data)
{
	return mount_single(fs_type, flags, data, capifs_fill_super);
}

static struct file_system_type capifs_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "capifs",
	.mount		= capifs_mount,
	.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>
5a0e3ad6	14	#include <linux/slab.h>
1da177e4 LT	15	#include <linux/namei.h>
	16	#include <linux/module.h>
	17	#include <linux/init.h>
	18	#include <linux/ctype.h>
4e57b681	19	#include <linux/sched.h> /* current */
1da177e4	20
6e21bd9a AB	21	#include "capifs.h"
6e21bd9a AB	22
1da177e4 LT	23	MODULE_DESCRIPTION("CAPI4Linux: /dev/capi/ filesystem");
	24	MODULE_AUTHOR("Carsten Paeth");
	25	MODULE_LICENSE("GPL");
	26
	27	/* ------------------------------------------------------------------ */
	28
1da177e4 LT	29	#define CAPIFS_SUPER_MAGIC (('C'<<8)\|'N')
	30
	31	static struct vfsmount *capifs_mnt;
e11e7ac1	32	static int capifs_mnt_count;
1da177e4 LT	33
	34	static struct {
	35	int setuid;
	36	int setgid;
	37	uid_t uid;
	38	gid_t gid;
	39	umode_t mode;
	40	} config = {.mode = 0600};
	41
	42	/* ------------------------------------------------------------------ */
	43
	44	static int capifs_remount(struct super_block s, int flags, char *data)
	45	{
	46	int setuid = 0;
	47	int setgid = 0;
	48	uid_t uid = 0;
	49	gid_t gid = 0;
	50	umode_t mode = 0600;
	51	char *this_char;
e55e212c	52	char *new_opt = kstrdup(data, GFP_KERNEL);
1da177e4 LT	53
	54	this_char = NULL;
	55	while ((this_char = strsep(&data, ",")) != NULL) {
	56	int n;
	57	char dummy;
	58	if (!*this_char)
	59	continue;
	60	if (sscanf(this_char, "uid=%i%c", &n, &dummy) == 1) {
	61	setuid = 1;
	62	uid = n;
	63	} else if (sscanf(this_char, "gid=%i%c", &n, &dummy) == 1) {
	64	setgid = 1;
	65	gid = n;
	66	} else if (sscanf(this_char, "mode=%o%c", &n, &dummy) == 1)
	67	mode = n & ~S_IFMT;
	68	else {
c24e9b3f	69	kfree(new_opt);
1da177e4 LT	70	printk("capifs: called with bogus options\n");
	71	return -EINVAL;
	72	}
	73	}
e55e212c	74
b0c4f322	75	mutex_lock(&s->s_root->d_inode->i_mutex);
e55e212c	76
b0c4f322	77	replace_mount_options(s, new_opt);
1da177e4 LT	78	config.setuid = setuid;
	79	config.setgid = setgid;
	80	config.uid = uid;
	81	config.gid = gid;
	82	config.mode = mode;
e55e212c	83
b0c4f322 AV	84	mutex_unlock(&s->s_root->d_inode->i_mutex);
b0c4f322 AV	85
1da177e4 LT	86	return 0;
	87	}
	88
b87221de	89	static const struct super_operations capifs_sops =
1da177e4 LT	90	{
	91	.statfs = simple_statfs,
	92	.remount_fs = capifs_remount,
e55e212c	93	.show_options = generic_show_options,
1da177e4 LT	94	};
	95
	96
	97	static int
	98	capifs_fill_super(struct super_block s, void data, int silent)
	99	{
	100	struct inode * inode;
	101
	102	s->s_blocksize = 1024;
	103	s->s_blocksize_bits = 10;
	104	s->s_magic = CAPIFS_SUPER_MAGIC;
	105	s->s_op = &capifs_sops;
	106	s->s_time_gran = 1;
	107
	108	inode = new_inode(s);
	109	if (!inode)
	110	goto fail;
	111	inode->i_ino = 1;
	112	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1da177e4 LT	113	inode->i_mode = S_IFDIR \| S_IRUGO \| S_IXUGO \| S_IWUSR;
	114	inode->i_op = &simple_dir_inode_operations;
	115	inode->i_fop = &simple_dir_operations;
	116	inode->i_nlink = 2;
	117
07ad603a	118	s->s_root = d_alloc_root(inode);
1da177e4 LT	119	if (s->s_root)
	120	return 0;
	121
	122	printk("capifs: get root dentry failed\n");
	123	iput(inode);
	124	fail:
	125	return -ENOMEM;
	126	}
	127
fc14f2fe AV	128	static struct dentry capifs_mount(struct file_system_type fs_type,
fc14f2fe AV	129	int flags, const char dev_name, void data)
1da177e4	130	{
fc14f2fe	131	return mount_single(fs_type, flags, data, capifs_fill_super);
1da177e4 LT	132	}
	133
	134	static struct file_system_type capifs_fs_type = {
	135	.owner = THIS_MODULE,
	136	.name = "capifs",
fc14f2fe	137	.mount = capifs_mount,
1da177e4 LT	138	.kill_sb = kill_anon_super,
	139	};
	140
e11e7ac1	141	static struct dentry *new_ncci(unsigned int number, dev_t device)
1da177e4	142	{
07ad603a JK	143	struct super_block *s = capifs_mnt->mnt_sb;
07ad603a JK	144	struct dentry *root = s->s_root;
1da177e4	145	struct dentry *dentry;
c947862f	146	struct inode *inode;
90926f0e JK	147	char name[10];
90926f0e JK	148	int namelen;
b0c4f322	149
07ad603a	150	mutex_lock(&root->d_inode->i_mutex);
90926f0e JK	151
90926f0e JK	152	namelen = sprintf(name, "%d", number);
07ad603a	153	dentry = lookup_one_len(name, root, namelen);
90926f0e JK	154	if (IS_ERR(dentry)) {
90926f0e JK	155	dentry = NULL;
c947862f	156	goto unlock_out;
90926f0e	157	}
c947862f JK	158
	159	if (dentry->d_inode) {
	160	dput(dentry);
90926f0e	161	dentry = NULL;
c947862f JK	162	goto unlock_out;
	163	}
	164
07ad603a	165	inode = new_inode(s);
c947862f JK	166	if (!inode) {
c947862f JK	167	dput(dentry);
90926f0e	168	dentry = NULL;
c947862f JK	169	goto unlock_out;
c947862f JK	170	}
b0c4f322 AV	171
b0c4f322 AV	172	/* config contents is protected by root's i_mutex */
0e164b68 DH	173	inode->i_uid = config.setuid ? config.uid : current_fsuid();
0e164b68 DH	174	inode->i_gid = config.setgid ? config.gid : current_fsgid();
1da177e4	175	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
c947862f	176	inode->i_ino = number + 2;
1da177e4	177	init_special_inode(inode, S_IFCHR\|config.mode, device);
1da177e4	178
c947862f	179	d_instantiate(dentry, inode);
90926f0e	180	dget(dentry);
c947862f JK	181
c947862f JK	182	unlock_out:
07ad603a	183	mutex_unlock(&root->d_inode->i_mutex);
90926f0e JK	184
90926f0e JK	185	return dentry;
1da177e4 LT	186	}
1da177e4 LT	187
e11e7ac1 JK	188	struct dentry *capifs_new_ncci(unsigned int number, dev_t device)
	189	{
	190	struct dentry *dentry;
	191
	192	if (simple_pin_fs(&capifs_fs_type, &capifs_mnt, &capifs_mnt_count) < 0)
	193	return NULL;
	194
	195	dentry = new_ncci(number, device);
	196	if (!dentry)
	197	simple_release_fs(&capifs_mnt, &capifs_mnt_count);
	198
	199	return dentry;
	200	}
	201
90926f0e	202	void capifs_free_ncci(struct dentry *dentry)
1da177e4	203	{
07ad603a	204	struct dentry *root = capifs_mnt->mnt_sb->s_root;
90926f0e JK	205	struct inode *inode;
	206
	207	if (!dentry)
	208	return;
	209
07ad603a	210	mutex_lock(&root->d_inode->i_mutex);
90926f0e JK	211
	212	inode = dentry->d_inode;
	213	if (inode) {
	214	drop_nlink(inode);
	215	d_delete(dentry);
1da177e4 LT	216	dput(dentry);
1da177e4 LT	217	}
90926f0e JK	218	dput(dentry);
90926f0e JK	219
07ad603a	220	mutex_unlock(&root->d_inode->i_mutex);
e11e7ac1 JK	221
e11e7ac1 JK	222	simple_release_fs(&capifs_mnt, &capifs_mnt_count);
1da177e4 LT	223	}
	224
	225	static int __init capifs_init(void)
	226	{
88549d6b	227	return register_filesystem(&capifs_fs_type);
1da177e4 LT	228	}
	229
	230	static void __exit capifs_exit(void)
	231	{
	232	unregister_filesystem(&capifs_fs_type);
1da177e4 LT	233	}
	234
	235	EXPORT_SYMBOL(capifs_new_ncci);
	236	EXPORT_SYMBOL(capifs_free_ncci);
	237
	238	module_init(capifs_init);
	239	module_exit(capifs_exit);