/* -*- 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/parser.h> #include <linux/fsnotify.h> #include <linux/seq_file.h> #define DEVPTS_SUPER_MAGIC 0x1cd1 #define DEVPTS_DEFAULT_MODE 0600 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 = DEVPTS_DEFAULT_MODE}; enum { Opt_uid, Opt_gid, Opt_mode, Opt_err }; static match_table_t tokens = { {Opt_uid, "uid=%u"}, {Opt_gid, "gid=%u"}, {Opt_mode, "mode=%o"}, {Opt_err, NULL} }; static int devpts_remount(struct super_block *sb, int *flags, char *data) { char *p; config.setuid = 0; config.setgid = 0; config.uid = 0; config.gid = 0; config.mode = DEVPTS_DEFAULT_MODE; while ((p = strsep(&data, ",")) != NULL) { substring_t args[MAX_OPT_ARGS]; int token; int option; if (!*p) continue; token = match_token(p, tokens, args); switch (token) { case Opt_uid: if (match_int(&args[0], &option)) return -EINVAL; config.uid = option; config.setuid = 1; break; case Opt_gid: if (match_int(&args[0], &option)) return -EINVAL; config.gid = option; config.setgid = 1; break; case Opt_mode: if (match_octal(&args[0], &option)) return -EINVAL; config.mode = option & S_IALLUGO; break; default: printk(KERN_ERR "devpts: called with bogus options\n"); return -EINVAL; } } return 0; } static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs) { if (config.setuid) seq_printf(seq, ",uid=%u", config.uid); if (config.setgid) seq_printf(seq, ",gid=%u", config.gid); seq_printf(seq, ",mode=%03o", config.mode); return 0; } static const struct super_operations devpts_sops = { .statfs = simple_statfs, .remount_fs = devpts_remount, .show_options = devpts_show_options, }; 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_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_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 int devpts_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, devpts_fill_super, mnt); } 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; mutex_lock(&root->d_inode->i_mutex); 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_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_private = tty; dentry = get_node(number); if (!IS_ERR(dentry) && !dentry->d_inode) { d_instantiate(dentry, inode); fsnotify_create(devpts_root->d_inode, dentry); } mutex_unlock(&devpts_root->d_inode->i_mutex); 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->i_private; dput(dentry); } mutex_unlock(&devpts_root->d_inode->i_mutex); 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); } mutex_unlock(&devpts_root->d_inode->i_mutex); } 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");