1/*
  2 *  Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
  3 *  Copyright 2005-2006 Ian Kent <raven@themaw.net>
  4 *
  5 * This file is part of the Linux kernel and is made available under
  6 * the terms of the GNU General Public License, version 2, or at your
  7 * option, any later version, incorporated herein by reference.
  8 */
  9
 10/* Internal header file for autofs */
 11
 12#include <linux/auto_fs4.h>
 13#include <linux/auto_dev-ioctl.h>
 14#include <linux/mutex.h>
 15#include <linux/spinlock.h>
 16#include <linux/list.h>
 17
 18/* This is the range of ioctl() numbers we claim as ours */
 19#define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
 20#define AUTOFS_IOC_COUNT     32
 21
 22#define AUTOFS_DEV_IOCTL_IOC_FIRST	(AUTOFS_DEV_IOCTL_VERSION)
 23#define AUTOFS_DEV_IOCTL_IOC_COUNT	(AUTOFS_IOC_COUNT - 11)
 24
 25#include <linux/kernel.h>
 26#include <linux/slab.h>
 27#include <linux/time.h>
 28#include <linux/string.h>
 29#include <linux/wait.h>
 30#include <linux/sched.h>
 31#include <linux/mount.h>
 32#include <linux/namei.h>
 33#include <asm/current.h>
 34#include <linux/uaccess.h>
 35
 36/* #define DEBUG */
 37
 38#ifdef pr_fmt
 39#undef pr_fmt
 40#endif
 41#define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__
 42
 43/*
 44 * Unified info structure.  This is pointed to by both the dentry and
 45 * inode structures.  Each file in the filesystem has an instance of this
 46 * structure.  It holds a reference to the dentry, so dentries are never
 47 * flushed while the file exists.  All name lookups are dealt with at the
 48 * dentry level, although the filesystem can interfere in the validation
 49 * process.  Readdir is implemented by traversing the dentry lists.
 50 */
 51struct autofs_info {
 52	struct dentry	*dentry;
 53	struct inode	*inode;
 54
 55	int		flags;
 56
 57	struct completion expire_complete;
 58
 59	struct list_head active;
 60	int active_count;
 61
 62	struct list_head expiring;
 63
 64	struct autofs_sb_info *sbi;
 65	unsigned long last_used;
 66	atomic_t count;
 67
 68	kuid_t uid;
 69	kgid_t gid;
 70};
 71
 72#define AUTOFS_INF_EXPIRING	(1<<0) /* dentry in the process of expiring */
 73#define AUTOFS_INF_NO_RCU	(1<<1) /* the dentry is being considered
 74					* for expiry, so RCU_walk is
 75					* not permitted
 76					*/
 77#define AUTOFS_INF_PENDING	(1<<2) /* dentry pending mount */
 78
 79struct autofs_wait_queue {
 80	wait_queue_head_t queue;
 81	struct autofs_wait_queue *next;
 82	autofs_wqt_t wait_queue_token;
 83	/* We use the following to see what we are waiting for */
 84	struct qstr name;
 85	u32 dev;
 86	u64 ino;
 87	kuid_t uid;
 88	kgid_t gid;
 89	pid_t pid;
 90	pid_t tgid;
 91	/* This is for status reporting upon return */
 92	int status;
 93	unsigned int wait_ctr;
 94};
 95
 96#define AUTOFS_SBI_MAGIC 0x6d4a556d
 97
 98struct autofs_sb_info {
 99	u32 magic;
100	int pipefd;
101	struct file *pipe;
102	struct pid *oz_pgrp;
103	int catatonic;
104	int version;
105	int sub_version;
106	int min_proto;
107	int max_proto;
108	unsigned long exp_timeout;
109	unsigned int type;
110	int reghost_enabled;
111	int needs_reghost;
112	struct super_block *sb;
113	struct mutex wq_mutex;
114	struct mutex pipe_mutex;
115	spinlock_t fs_lock;
116	struct autofs_wait_queue *queues; /* Wait queue pointer */
117	spinlock_t lookup_lock;
118	struct list_head active_list;
119	struct list_head expiring_list;
120	struct rcu_head rcu;
121};
122
123static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
124{
125	return (struct autofs_sb_info *)(sb->s_fs_info);
126}
127
128static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
129{
130	return (struct autofs_info *)(dentry->d_fsdata);
131}
132
133/* autofs4_oz_mode(): do we see the man behind the curtain?  (The
134 * processes which do manipulations for us in user space sees the raw
135 * filesystem without "magic".)
136 */
137static inline int autofs4_oz_mode(struct autofs_sb_info *sbi)
138{
139	return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
140}
141
142struct inode *autofs4_get_inode(struct super_block *, umode_t);
143void autofs4_free_ino(struct autofs_info *);
144
145/* Expiration */
146int is_autofs4_dentry(struct dentry *);
147int autofs4_expire_wait(struct dentry *dentry, int rcu_walk);
148int autofs4_expire_run(struct super_block *, struct vfsmount *,
149		       struct autofs_sb_info *,
150		       struct autofs_packet_expire __user *);
151int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
152			    struct autofs_sb_info *sbi, int when);
153int autofs4_expire_multi(struct super_block *, struct vfsmount *,
154			 struct autofs_sb_info *, int __user *);
155struct dentry *autofs4_expire_direct(struct super_block *sb,
156				     struct vfsmount *mnt,
157				     struct autofs_sb_info *sbi, int how);
158struct dentry *autofs4_expire_indirect(struct super_block *sb,
159				       struct vfsmount *mnt,
160				       struct autofs_sb_info *sbi, int how);
161
162/* Device node initialization */
163
164int autofs_dev_ioctl_init(void);
165void autofs_dev_ioctl_exit(void);
166
167/* Operations structures */
168
169extern const struct inode_operations autofs4_symlink_inode_operations;
170extern const struct inode_operations autofs4_dir_inode_operations;
171extern const struct file_operations autofs4_dir_operations;
172extern const struct file_operations autofs4_root_operations;
173extern const struct dentry_operations autofs4_dentry_operations;
174
175/* VFS automount flags management functions */
176static inline void __managed_dentry_set_managed(struct dentry *dentry)
177{
178	dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
179}
180
181static inline void managed_dentry_set_managed(struct dentry *dentry)
182{
183	spin_lock(&dentry->d_lock);
184	__managed_dentry_set_managed(dentry);
185	spin_unlock(&dentry->d_lock);
186}
187
188static inline void __managed_dentry_clear_managed(struct dentry *dentry)
189{
190	dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
191}
192
193static inline void managed_dentry_clear_managed(struct dentry *dentry)
194{
195	spin_lock(&dentry->d_lock);
196	__managed_dentry_clear_managed(dentry);
197	spin_unlock(&dentry->d_lock);
198}
199
200/* Initializing function */
201
202int autofs4_fill_super(struct super_block *, void *, int);
203struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
204void autofs4_clean_ino(struct autofs_info *);
205
206static inline int autofs_prepare_pipe(struct file *pipe)
207{
208	if (!(pipe->f_mode & FMODE_CAN_WRITE))
209		return -EINVAL;
210	if (!S_ISFIFO(file_inode(pipe)->i_mode))
211		return -EINVAL;
212	/* We want a packet pipe */
213	pipe->f_flags |= O_DIRECT;
214	return 0;
215}
216
217/* Queue management functions */
218
219int autofs4_wait(struct autofs_sb_info *, struct dentry *, enum autofs_notify);
220int autofs4_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
221void autofs4_catatonic_mode(struct autofs_sb_info *);
222
223static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
224{
225	return new_encode_dev(sbi->sb->s_dev);
226}
227
228static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
229{
230	return d_inode(sbi->sb->s_root)->i_ino;
231}
232
233static inline void __autofs4_add_expiring(struct dentry *dentry)
234{
235	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
236	struct autofs_info *ino = autofs4_dentry_ino(dentry);
237
238	if (ino) {
239		if (list_empty(&ino->expiring))
240			list_add(&ino->expiring, &sbi->expiring_list);
241	}
242}
243
244static inline void autofs4_add_expiring(struct dentry *dentry)
245{
246	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
247	struct autofs_info *ino = autofs4_dentry_ino(dentry);
248
249	if (ino) {
250		spin_lock(&sbi->lookup_lock);
251		if (list_empty(&ino->expiring))
252			list_add(&ino->expiring, &sbi->expiring_list);
253		spin_unlock(&sbi->lookup_lock);
254	}
255}
256
257static inline void autofs4_del_expiring(struct dentry *dentry)
258{
259	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
260	struct autofs_info *ino = autofs4_dentry_ino(dentry);
261
262	if (ino) {
263		spin_lock(&sbi->lookup_lock);
264		if (!list_empty(&ino->expiring))
265			list_del_init(&ino->expiring);
266		spin_unlock(&sbi->lookup_lock);
267	}
268}
269
270extern void autofs4_kill_sb(struct super_block *);