1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
4 * Copyright 2005-2006 Ian Kent <raven@themaw.net>
7 /* Internal header file for autofs */
9 #include <linux/auto_fs.h>
10 #include <linux/auto_dev-ioctl.h>
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/time.h>
15 #include <linux/string.h>
16 #include <linux/wait.h>
17 #include <linux/sched.h>
18 #include <linux/sched/signal.h>
19 #include <linux/mount.h>
20 #include <linux/namei.h>
21 #include <linux/uaccess.h>
22 #include <linux/mutex.h>
23 #include <linux/spinlock.h>
24 #include <linux/list.h>
25 #include <linux/completion.h>
26 #include <linux/file.h>
27 #include <linux/magic.h>
28 #include <linux/fs_context.h>
29 #include <linux/fs_parser.h>
31 /* This is the range of ioctl() numbers we claim as ours */
32 #define AUTOFS_IOC_FIRST AUTOFS_IOC_READY
33 #define AUTOFS_IOC_COUNT 32
35 #define AUTOFS_DEV_IOCTL_IOC_FIRST (AUTOFS_DEV_IOCTL_VERSION)
36 #define AUTOFS_DEV_IOCTL_IOC_COUNT \
37 (AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD)
42 #define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__
44 extern struct file_system_type autofs_fs_type;
47 * Unified info structure. This is pointed to by both the dentry and
48 * inode structures. Each file in the filesystem has an instance of this
49 * structure. It holds a reference to the dentry, so dentries are never
50 * flushed while the file exists. All name lookups are dealt with at the
51 * dentry level, although the filesystem can interfere in the validation
52 * process. Readdir is implemented by traversing the dentry lists.
55 struct dentry *dentry;
58 struct completion expire_complete;
60 struct list_head active;
62 struct list_head expiring;
64 struct autofs_sb_info *sbi;
65 unsigned long last_used;
73 #define AUTOFS_INF_EXPIRING (1<<0) /* dentry in the process of expiring */
74 #define AUTOFS_INF_WANT_EXPIRE (1<<1) /* the dentry is being considered
75 * for expiry, so RCU_walk is
76 * not permitted. If it progresses to
77 * actual expiry attempt, the flag is
78 * not cleared when EXPIRING is set -
79 * in that case it gets cleared only
80 * when it comes to clearing EXPIRING.
82 #define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */
84 struct autofs_wait_queue {
85 wait_queue_head_t queue;
86 struct autofs_wait_queue *next;
87 autofs_wqt_t wait_queue_token;
88 /* We use the following to see what we are waiting for */
97 /* This is for status reporting upon return */
99 unsigned int wait_ctr;
102 #define AUTOFS_SBI_MAGIC 0x6d4a556d
104 #define AUTOFS_SBI_CATATONIC 0x0001
105 #define AUTOFS_SBI_STRICTEXPIRE 0x0002
106 #define AUTOFS_SBI_IGNORE 0x0004
108 struct autofs_sb_info {
118 unsigned long exp_timeout;
120 struct super_block *sb;
121 struct mutex wq_mutex;
122 struct mutex pipe_mutex;
124 struct autofs_wait_queue *queues; /* Wait queue pointer */
125 spinlock_t lookup_lock;
126 struct list_head active_list;
127 struct list_head expiring_list;
131 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
133 return (struct autofs_sb_info *)(sb->s_fs_info);
136 static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry)
138 return (struct autofs_info *)(dentry->d_fsdata);
141 /* autofs_oz_mode(): do we see the man behind the curtain? (The
142 * processes which do manipulations for us in user space sees the raw
143 * filesystem without "magic".)
145 static inline int autofs_oz_mode(struct autofs_sb_info *sbi)
147 return ((sbi->flags & AUTOFS_SBI_CATATONIC) ||
148 task_pgrp(current) == sbi->oz_pgrp);
151 static inline bool autofs_empty(struct autofs_info *ino)
153 return ino->count < 2;
156 struct inode *autofs_get_inode(struct super_block *, umode_t);
157 void autofs_free_ino(struct autofs_info *);
160 int is_autofs_dentry(struct dentry *);
161 int autofs_expire_wait(const struct path *path, int rcu_walk);
162 int autofs_expire_run(struct super_block *, struct vfsmount *,
163 struct autofs_sb_info *,
164 struct autofs_packet_expire __user *);
165 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
166 struct autofs_sb_info *sbi, unsigned int how);
167 int autofs_expire_multi(struct super_block *, struct vfsmount *,
168 struct autofs_sb_info *, int __user *);
170 /* Device node initialization */
172 int autofs_dev_ioctl_init(void);
173 void autofs_dev_ioctl_exit(void);
175 /* Operations structures */
177 extern const struct inode_operations autofs_symlink_inode_operations;
178 extern const struct inode_operations autofs_dir_inode_operations;
179 extern const struct file_operations autofs_dir_operations;
180 extern const struct file_operations autofs_root_operations;
181 extern const struct dentry_operations autofs_dentry_operations;
183 /* VFS automount flags management functions */
184 static inline void __managed_dentry_set_managed(struct dentry *dentry)
186 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
189 static inline void managed_dentry_set_managed(struct dentry *dentry)
191 spin_lock(&dentry->d_lock);
192 __managed_dentry_set_managed(dentry);
193 spin_unlock(&dentry->d_lock);
196 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
198 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
201 static inline void managed_dentry_clear_managed(struct dentry *dentry)
203 spin_lock(&dentry->d_lock);
204 __managed_dentry_clear_managed(dentry);
205 spin_unlock(&dentry->d_lock);
208 /* Initializing function */
210 extern const struct fs_parameter_spec autofs_param_specs[];
211 int autofs_init_fs_context(struct fs_context *fc);
212 struct autofs_info *autofs_new_ino(struct autofs_sb_info *);
213 void autofs_clean_ino(struct autofs_info *);
215 static inline int autofs_check_pipe(struct file *pipe)
217 if (!(pipe->f_mode & FMODE_CAN_WRITE))
219 if (!S_ISFIFO(file_inode(pipe)->i_mode))
224 static inline void autofs_set_packet_pipe_flags(struct file *pipe)
226 /* We want a packet pipe */
227 pipe->f_flags |= O_DIRECT;
228 /* We don't expect -EAGAIN */
229 pipe->f_flags &= ~O_NONBLOCK;
232 static inline int autofs_prepare_pipe(struct file *pipe)
234 int ret = autofs_check_pipe(pipe);
237 autofs_set_packet_pipe_flags(pipe);
241 /* Queue management functions */
243 int autofs_wait(struct autofs_sb_info *,
244 const struct path *, enum autofs_notify);
245 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
246 void autofs_catatonic_mode(struct autofs_sb_info *);
248 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)
250 return new_encode_dev(sbi->sb->s_dev);
253 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi)
255 return d_inode(sbi->sb->s_root)->i_ino;
258 static inline void __autofs_add_expiring(struct dentry *dentry)
260 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
261 struct autofs_info *ino = autofs_dentry_ino(dentry);
264 if (list_empty(&ino->expiring))
265 list_add(&ino->expiring, &sbi->expiring_list);
269 static inline void autofs_add_expiring(struct dentry *dentry)
271 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
272 struct autofs_info *ino = autofs_dentry_ino(dentry);
275 spin_lock(&sbi->lookup_lock);
276 if (list_empty(&ino->expiring))
277 list_add(&ino->expiring, &sbi->expiring_list);
278 spin_unlock(&sbi->lookup_lock);
282 static inline void autofs_del_expiring(struct dentry *dentry)
284 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
285 struct autofs_info *ino = autofs_dentry_ino(dentry);
288 spin_lock(&sbi->lookup_lock);
289 if (!list_empty(&ino->expiring))
290 list_del_init(&ino->expiring);
291 spin_unlock(&sbi->lookup_lock);
295 void autofs_kill_sb(struct super_block *);