1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
4 * Copyright 2005-2006 Ian Kent <raven@themaw.net>
5 */
6
7/* Internal header file for autofs */
8
9#include <linux/auto_fs.h>
10#include <linux/auto_dev-ioctl.h>
11
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>
30
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
34
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)
38
39#ifdef pr_fmt
40#undef pr_fmt
41#endif
42#define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__
43
44extern struct file_system_type autofs_fs_type;
45
46/*
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.
53 */
54struct autofs_info {
55 struct dentry *dentry;
56 int flags;
57
58 struct completion expire_complete;
59
60 struct list_head active;
61
62 struct list_head expiring;
63
64 struct autofs_sb_info *sbi;
65 unsigned long exp_timeout;
66 unsigned long last_used;
67 int count;
68
69 kuid_t uid;
70 kgid_t gid;
71 struct rcu_head rcu;
72};
73
74#define AUTOFS_INF_EXPIRING (1<<0) /* dentry in the process of expiring */
75#define AUTOFS_INF_WANT_EXPIRE (1<<1) /* the dentry is being considered
76 * for expiry, so RCU_walk is
77 * not permitted. If it progresses to
78 * actual expiry attempt, the flag is
79 * not cleared when EXPIRING is set -
80 * in that case it gets cleared only
81 * when it comes to clearing EXPIRING.
82 */
83#define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */
84
85#define AUTOFS_INF_EXPIRE_SET (1<<3) /* per-dentry expire timeout set for
86 this mount point.
87 */
88struct autofs_wait_queue {
89 wait_queue_head_t queue;
90 struct autofs_wait_queue *next;
91 autofs_wqt_t wait_queue_token;
92 /* We use the following to see what we are waiting for */
93 struct qstr name;
94 u32 offset;
95 u32 dev;
96 u64 ino;
97 kuid_t uid;
98 kgid_t gid;
99 pid_t pid;
100 pid_t tgid;
101 /* This is for status reporting upon return */
102 int status;
103 unsigned int wait_ctr;
104};
105
106#define AUTOFS_SBI_MAGIC 0x6d4a556d
107
108#define AUTOFS_SBI_CATATONIC 0x0001
109#define AUTOFS_SBI_STRICTEXPIRE 0x0002
110#define AUTOFS_SBI_IGNORE 0x0004
111
112struct autofs_sb_info {
113 u32 magic;
114 int pipefd;
115 struct file *pipe;
116 struct pid *oz_pgrp;
117 int version;
118 int sub_version;
119 int min_proto;
120 int max_proto;
121 unsigned int flags;
122 unsigned long exp_timeout;
123 unsigned int type;
124 struct super_block *sb;
125 struct mutex wq_mutex;
126 struct mutex pipe_mutex;
127 spinlock_t fs_lock;
128 struct autofs_wait_queue *queues; /* Wait queue pointer */
129 spinlock_t lookup_lock;
130 struct list_head active_list;
131 struct list_head expiring_list;
132 struct rcu_head rcu;
133};
134
135static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
136{
137 return (struct autofs_sb_info *)(sb->s_fs_info);
138}
139
140static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry)
141{
142 return (struct autofs_info *)(dentry->d_fsdata);
143}
144
145/* autofs_oz_mode(): do we see the man behind the curtain? (The
146 * processes which do manipulations for us in user space sees the raw
147 * filesystem without "magic".)
148 */
149static inline int autofs_oz_mode(struct autofs_sb_info *sbi)
150{
151 return ((sbi->flags & AUTOFS_SBI_CATATONIC) ||
152 task_pgrp(current) == sbi->oz_pgrp);
153}
154
155static inline bool autofs_empty(struct autofs_info *ino)
156{
157 return ino->count < 2;
158}
159
160struct inode *autofs_get_inode(struct super_block *, umode_t);
161void autofs_free_ino(struct autofs_info *);
162
163/* Expiration */
164int is_autofs_dentry(struct dentry *);
165int autofs_expire_wait(const struct path *path, int rcu_walk);
166int autofs_expire_run(struct super_block *, struct vfsmount *,
167 struct autofs_sb_info *,
168 struct autofs_packet_expire __user *);
169int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
170 struct autofs_sb_info *sbi, unsigned int how);
171int autofs_expire_multi(struct super_block *, struct vfsmount *,
172 struct autofs_sb_info *, int __user *);
173
174/* Device node initialization */
175
176int autofs_dev_ioctl_init(void);
177void autofs_dev_ioctl_exit(void);
178
179/* Operations structures */
180
181extern const struct inode_operations autofs_symlink_inode_operations;
182extern const struct inode_operations autofs_dir_inode_operations;
183extern const struct file_operations autofs_dir_operations;
184extern const struct file_operations autofs_root_operations;
185extern const struct dentry_operations autofs_dentry_operations;
186
187/* VFS automount flags management functions */
188static inline void __managed_dentry_set_managed(struct dentry *dentry)
189{
190 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
191}
192
193static inline void managed_dentry_set_managed(struct dentry *dentry)
194{
195 spin_lock(lock: &dentry->d_lock);
196 __managed_dentry_set_managed(dentry);
197 spin_unlock(lock: &dentry->d_lock);
198}
199
200static inline void __managed_dentry_clear_managed(struct dentry *dentry)
201{
202 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
203}
204
205static inline void managed_dentry_clear_managed(struct dentry *dentry)
206{
207 spin_lock(lock: &dentry->d_lock);
208 __managed_dentry_clear_managed(dentry);
209 spin_unlock(lock: &dentry->d_lock);
210}
211
212/* Initializing function */
213
214extern const struct fs_parameter_spec autofs_param_specs[];
215int autofs_init_fs_context(struct fs_context *fc);
216struct autofs_info *autofs_new_ino(struct autofs_sb_info *);
217void autofs_clean_ino(struct autofs_info *);
218
219static inline int autofs_check_pipe(struct file *pipe)
220{
221 if (pipe->f_mode & FMODE_PATH)
222 return -EINVAL;
223 if (!(pipe->f_mode & FMODE_CAN_WRITE))
224 return -EINVAL;
225 if (!S_ISFIFO(file_inode(pipe)->i_mode))
226 return -EINVAL;
227 return 0;
228}
229
230static inline void autofs_set_packet_pipe_flags(struct file *pipe)
231{
232 /* We want a packet pipe */
233 pipe->f_flags |= O_DIRECT;
234 /* We don't expect -EAGAIN */
235 pipe->f_flags &= ~O_NONBLOCK;
236}
237
238static inline int autofs_prepare_pipe(struct file *pipe)
239{
240 int ret = autofs_check_pipe(pipe);
241 if (ret < 0)
242 return ret;
243 autofs_set_packet_pipe_flags(pipe);
244 return 0;
245}
246
247/* Queue management functions */
248
249int autofs_wait(struct autofs_sb_info *,
250 const struct path *, enum autofs_notify);
251int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
252void autofs_catatonic_mode(struct autofs_sb_info *);
253
254static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)
255{
256 return new_encode_dev(dev: sbi->sb->s_dev);
257}
258
259static inline u64 autofs_get_ino(struct autofs_sb_info *sbi)
260{
261 return d_inode(dentry: sbi->sb->s_root)->i_ino;
262}
263
264static inline void __autofs_add_expiring(struct dentry *dentry)
265{
266 struct autofs_sb_info *sbi = autofs_sbi(sb: dentry->d_sb);
267 struct autofs_info *ino = autofs_dentry_ino(dentry);
268
269 if (ino) {
270 if (list_empty(head: &ino->expiring))
271 list_add(new: &ino->expiring, head: &sbi->expiring_list);
272 }
273}
274
275static inline void autofs_add_expiring(struct dentry *dentry)
276{
277 struct autofs_sb_info *sbi = autofs_sbi(sb: dentry->d_sb);
278 struct autofs_info *ino = autofs_dentry_ino(dentry);
279
280 if (ino) {
281 spin_lock(lock: &sbi->lookup_lock);
282 if (list_empty(head: &ino->expiring))
283 list_add(new: &ino->expiring, head: &sbi->expiring_list);
284 spin_unlock(lock: &sbi->lookup_lock);
285 }
286}
287
288static inline void autofs_del_expiring(struct dentry *dentry)
289{
290 struct autofs_sb_info *sbi = autofs_sbi(sb: dentry->d_sb);
291 struct autofs_info *ino = autofs_dentry_ino(dentry);
292
293 if (ino) {
294 spin_lock(lock: &sbi->lookup_lock);
295 if (!list_empty(head: &ino->expiring))
296 list_del_init(entry: &ino->expiring);
297 spin_unlock(lock: &sbi->lookup_lock);
298 }
299}
300
301void autofs_kill_sb(struct super_block *);
302