diff options
Diffstat (limited to 'fs/devpts/inode.c')
| -rw-r--r-- | fs/devpts/inode.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c new file mode 100644 index 00000000000..1571c8d6c23 --- /dev/null +++ b/fs/devpts/inode.c @@ -0,0 +1,242 @@ +/* -*- 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 int +devpts_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"); |