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 last_used;
66 int count;
67
68 kuid_t uid;
69 kgid_t gid;
70 struct rcu_head rcu;
71};
72
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.
81 */
82#define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */
83
84struct 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 */
89 struct qstr name;
90 u32 offset;
91 u32 dev;
92 u64 ino;
93 kuid_t uid;
94 kgid_t gid;
95 pid_t pid;
96 pid_t tgid;
97 /* This is for status reporting upon return */
98 int status;
99 unsigned int wait_ctr;
100};
101
102#define AUTOFS_SBI_MAGIC 0x6d4a556d
103
104#define AUTOFS_SBI_CATATONIC 0x0001
105#define AUTOFS_SBI_STRICTEXPIRE 0x0002
106#define AUTOFS_SBI_IGNORE 0x0004
107
108struct autofs_sb_info {
109 u32 magic;
110 int pipefd;
111 struct file *pipe;
112 struct pid *oz_pgrp;
113 int version;
114 int sub_version;
115 int min_proto;
116 int max_proto;
117 unsigned int flags;
118 unsigned long exp_timeout;
119 unsigned int type;
120 struct super_block *sb;
121 struct mutex wq_mutex;
122 struct mutex pipe_mutex;
123 spinlock_t fs_lock;
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;
128 struct rcu_head rcu;
129};
130
131static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
132{
133 return (struct autofs_sb_info *)(sb->s_fs_info);
134}
135
136static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry)
137{
138 return (struct autofs_info *)(dentry->d_fsdata);
139}
140
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".)
144 */
145static inline int autofs_oz_mode(struct autofs_sb_info *sbi)
146{
147 return ((sbi->flags & AUTOFS_SBI_CATATONIC) ||
148 task_pgrp(current) == sbi->oz_pgrp);
149}
150
151static inline bool autofs_empty(struct autofs_info *ino)
152{
153 return ino->count < 2;
154}
155
156struct inode *autofs_get_inode(struct super_block *, umode_t);
157void autofs_free_ino(struct autofs_info *);
158
159/* Expiration */
160int is_autofs_dentry(struct dentry *);
161int autofs_expire_wait(const struct path *path, int rcu_walk);
162int autofs_expire_run(struct super_block *, struct vfsmount *,
163 struct autofs_sb_info *,
164 struct autofs_packet_expire __user *);
165int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
166 struct autofs_sb_info *sbi, unsigned int how);
167int autofs_expire_multi(struct super_block *, struct vfsmount *,
168 struct autofs_sb_info *, int __user *);
169
170/* Device node initialization */
171
172int autofs_dev_ioctl_init(void);
173void autofs_dev_ioctl_exit(void);
174
175/* Operations structures */
176
177extern const struct inode_operations autofs_symlink_inode_operations;
178extern const struct inode_operations autofs_dir_inode_operations;
179extern const struct file_operations autofs_dir_operations;
180extern const struct file_operations autofs_root_operations;
181extern const struct dentry_operations autofs_dentry_operations;
182
183/* VFS automount flags management functions */
184static inline void __managed_dentry_set_managed(struct dentry *dentry)
185{
186 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
187}
188
189static inline void managed_dentry_set_managed(struct dentry *dentry)
190{
191 spin_lock(lock: &dentry->d_lock);
192 __managed_dentry_set_managed(dentry);
193 spin_unlock(lock: &dentry->d_lock);
194}
195
196static inline void __managed_dentry_clear_managed(struct dentry *dentry)
197{
198 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
199}
200
201static inline void managed_dentry_clear_managed(struct dentry *dentry)
202{
203 spin_lock(lock: &dentry->d_lock);
204 __managed_dentry_clear_managed(dentry);
205 spin_unlock(lock: &dentry->d_lock);
206}
207
208/* Initializing function */
209
210extern const struct fs_parameter_spec autofs_param_specs[];
211int autofs_init_fs_context(struct fs_context *fc);
212struct autofs_info *autofs_new_ino(struct autofs_sb_info *);
213void autofs_clean_ino(struct autofs_info *);
214
215static inline int autofs_check_pipe(struct file *pipe)
216{
217 if (!(pipe->f_mode & FMODE_CAN_WRITE))
218 return -EINVAL;
219 if (!S_ISFIFO(file_inode(pipe)->i_mode))
220 return -EINVAL;
221 return 0;
222}
223
224static inline void autofs_set_packet_pipe_flags(struct file *pipe)
225{
226 /* We want a packet pipe */
227 pipe->f_flags |= O_DIRECT;
228 /* We don't expect -EAGAIN */
229 pipe->f_flags &= ~O_NONBLOCK;
230}
231
232static inline int autofs_prepare_pipe(struct file *pipe)
233{
234 int ret = autofs_check_pipe(pipe);
235 if (ret < 0)
236 return ret;
237 autofs_set_packet_pipe_flags(pipe);
238 return 0;
239}
240
241/* Queue management functions */
242
243int autofs_wait(struct autofs_sb_info *,
244 const struct path *, enum autofs_notify);
245int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
246void autofs_catatonic_mode(struct autofs_sb_info *);
247
248static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)
249{
250 return new_encode_dev(dev: sbi->sb->s_dev);
251}
252
253static inline u64 autofs_get_ino(struct autofs_sb_info *sbi)
254{
255 return d_inode(dentry: sbi->sb->s_root)->i_ino;
256}
257
258static inline void __autofs_add_expiring(struct dentry *dentry)
259{
260 struct autofs_sb_info *sbi = autofs_sbi(sb: dentry->d_sb);
261 struct autofs_info *ino = autofs_dentry_ino(dentry);
262
263 if (ino) {
264 if (list_empty(head: &ino->expiring))
265 list_add(new: &ino->expiring, head: &sbi->expiring_list);
266 }
267}
268
269static inline void autofs_add_expiring(struct dentry *dentry)
270{
271 struct autofs_sb_info *sbi = autofs_sbi(sb: dentry->d_sb);
272 struct autofs_info *ino = autofs_dentry_ino(dentry);
273
274 if (ino) {
275 spin_lock(lock: &sbi->lookup_lock);
276 if (list_empty(head: &ino->expiring))
277 list_add(new: &ino->expiring, head: &sbi->expiring_list);
278 spin_unlock(lock: &sbi->lookup_lock);
279 }
280}
281
282static inline void autofs_del_expiring(struct dentry *dentry)
283{
284 struct autofs_sb_info *sbi = autofs_sbi(sb: dentry->d_sb);
285 struct autofs_info *ino = autofs_dentry_ino(dentry);
286
287 if (ino) {
288 spin_lock(lock: &sbi->lookup_lock);
289 if (!list_empty(head: &ino->expiring))
290 list_del_init(entry: &ino->expiring);
291 spin_unlock(lock: &sbi->lookup_lock);
292 }
293}
294
295void autofs_kill_sb(struct super_block *);
296

source code of linux/fs/autofs/autofs_i.h