/* -*- linux-c -*- --------------------------------------------------------- * * * linux/fs/devpts/inode.c * *  Copyright 1998-2004 H. Peter Anvin -- All Rights Reserved * * This file is part of the Linux kernel and is made available under * the terms of the GNU General Public License, version 2, or at your * option, any later version, incorporated herein by reference. * * ------------------------------------------------------------------------- */ #include <linux/module.h>#include <linux/init.h>#include <linux/fs.h>#include <linux/sched.h>#include <linux/namei.h>#include <linux/mount.h>#include <linux/tty.h>#include <linux/devpts_fs.h>#include <linux/xattr.h> #define DEVPTS_SUPER_MAGIC 0x1cd1 extern struct xattr_handler devpts_xattr_security_handler; static struct xattr_handler *devpts_xattr_handlers[] = {#ifdef CONFIG_DEVPTS_FS_SECURITY	&devpts_xattr_security_handler,#endif	NULL}; static struct inode_operations devpts_file_inode_operations = {#ifdef CONFIG_DEVPTS_FS_XATTR	.setxattr	= generic_setxattr,	.getxattr	= generic_getxattr,	.listxattr	= generic_listxattr,	.removexattr	= generic_removexattr,#endif}; static struct vfsmount *devpts_mnt;static struct dentry *devpts_root; static struct {	int setuid;	int setgid;	uid_t   uid;	gid_t   gid;	umode_t mode;} config = {.mode = 0600}; static int devpts_remount(struct super_block *sb, 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; 	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 {			printk("devpts: called with bogus options\n");			return -EINVAL;		}	}	config.setuid  = setuid;	config.setgid  = setgid;	config.uid     = uid;	config.gid     = gid;	config.mode    = mode; 	return 0;} static struct super_operations devpts_sops = {	.statfs		= simple_statfs,	.remount_fs	= devpts_remount,}; static intdevpts_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 = DEVPTS_SUPER_MAGIC;	s->s_op = &devpts_sops;	s->s_xattr = devpts_xattr_handlers;	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_blocks = 0;	inode->i_blksize = 1024;	inode->i_uid = inode->i_gid = 0;	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; 	devpts_root = s->s_root = d_alloc_root(inode);	if (s->s_root)		return 0;		printk("devpts: get root dentry failed\n");	iput(inode);fail:	return -ENOMEM;} static struct super_block *devpts_get_sb(struct file_system_type *fs_type,	int flags, const char *dev_name, void *data){	return get_sb_single(fs_type, flags, data, devpts_fill_super);} static struct file_system_type devpts_fs_type = {	.owner		= THIS_MODULE,	.name		= "devpts",	.get_sb		= devpts_get_sb,	.kill_sb	= kill_anon_super,}; /* * The normal naming convention is simply /dev/pts/<number>; this conforms * to the System V naming convention */ static struct dentry *get_node(int num){	char s[12];	struct dentry *root = devpts_root;	down(&root->d_inode->i_sem);	return lookup_one_len(s, root, sprintf(s, "%d", num));} int devpts_pty_new(struct tty_struct *tty){	int number = tty->index;	struct tty_driver *driver = tty->driver;	dev_t device = MKDEV(driver->major, driver->minor_start+number);	struct dentry *dentry;	struct inode *inode = new_inode(devpts_mnt->mnt_sb); 	/* We're supposed to be given the slave end of a pty */	BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY);	BUG_ON(driver->subtype != PTY_TYPE_SLAVE); 	if (!inode)		return -ENOMEM; 	inode->i_ino = number+2;	inode->i_blksize = 1024;	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;	init_special_inode(inode, S_IFCHR|config.mode, device);	inode->i_op = &devpts_file_inode_operations;	inode->u.generic_ip = tty; 	dentry = get_node(number);	if (!IS_ERR(dentry) && !dentry->d_inode)		d_instantiate(dentry, inode); 	up(&devpts_root->d_inode->i_sem); 	return 0;} struct tty_struct *devpts_get_tty(int number){	struct dentry *dentry = get_node(number);	struct tty_struct *tty; 	tty = NULL;	if (!IS_ERR(dentry)) {		if (dentry->d_inode)			tty = dentry->d_inode->u.generic_ip;		dput(dentry);	} 	up(&devpts_root->d_inode->i_sem); 	return tty;} void devpts_pty_kill(int number){	struct dentry *dentry = get_node(number); 	if (!IS_ERR(dentry)) {		struct inode *inode = dentry->d_inode;		if (inode) {			inode->i_nlink--;			d_delete(dentry);			dput(dentry);		}		dput(dentry);	}	up(&devpts_root->d_inode->i_sem);} static int __init init_devpts_fs(void){	int err = register_filesystem(&devpts_fs_type);	if (!err) {		devpts_mnt = kern_mount(&devpts_fs_type);		if (IS_ERR(devpts_mnt))			err = PTR_ERR(devpts_mnt);	}	return err;} static void __exit exit_devpts_fs(void){	unregister_filesystem(&devpts_fs_type);	mntput(devpts_mnt);} module_init(init_devpts_fs)module_exit(exit_devpts_fs)MODULE_LICENSE("GPL");