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
44 extern 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 */
54 struct 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 */
88 struct 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
112 struct 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
autofs_sbi(struct super_block * sb)135 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
136 {
137 return (struct autofs_sb_info *)(sb->s_fs_info);
138 }
139
autofs_dentry_ino(struct dentry * dentry)140 static 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 */
autofs_oz_mode(struct autofs_sb_info * sbi)149 static 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
autofs_empty(struct autofs_info * ino)155 static inline bool autofs_empty(struct autofs_info *ino)
156 {
157 return ino->count < 2;
158 }
159
160 struct inode *autofs_get_inode(struct super_block *, umode_t);
161 void autofs_free_ino(struct autofs_info *);
162
163 /* Expiration */
164 int is_autofs_dentry(struct dentry *);
165 int autofs_expire_wait(const struct path *path, int rcu_walk);
166 int autofs_expire_run(struct super_block *, struct vfsmount *,
167 struct autofs_sb_info *,
168 struct autofs_packet_expire __user *);
169 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
170 struct autofs_sb_info *sbi, unsigned int how);
171 int autofs_expire_multi(struct super_block *, struct vfsmount *,
172 struct autofs_sb_info *, int __user *);
173
174 /* Device node initialization */
175
176 int autofs_dev_ioctl_init(void);
177 void autofs_dev_ioctl_exit(void);
178
179 /* Operations structures */
180
181 extern const struct inode_operations autofs_symlink_inode_operations;
182 extern const struct inode_operations autofs_dir_inode_operations;
183 extern const struct file_operations autofs_dir_operations;
184 extern const struct file_operations autofs_root_operations;
185 extern const struct dentry_operations autofs_dentry_operations;
186
187 /* VFS automount flags management functions */
__managed_dentry_set_managed(struct dentry * dentry)188 static inline void __managed_dentry_set_managed(struct dentry *dentry)
189 {
190 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
191 }
192
managed_dentry_set_managed(struct dentry * dentry)193 static inline void managed_dentry_set_managed(struct dentry *dentry)
194 {
195 spin_lock(&dentry->d_lock);
196 __managed_dentry_set_managed(dentry);
197 spin_unlock(&dentry->d_lock);
198 }
199
__managed_dentry_clear_managed(struct dentry * dentry)200 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
201 {
202 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
203 }
204
managed_dentry_clear_managed(struct dentry * dentry)205 static inline void managed_dentry_clear_managed(struct dentry *dentry)
206 {
207 spin_lock(&dentry->d_lock);
208 __managed_dentry_clear_managed(dentry);
209 spin_unlock(&dentry->d_lock);
210 }
211
212 /* Initializing function */
213
214 extern const struct fs_parameter_spec autofs_param_specs[];
215 int autofs_init_fs_context(struct fs_context *fc);
216 struct autofs_info *autofs_new_ino(struct autofs_sb_info *);
217 void autofs_clean_ino(struct autofs_info *);
218
autofs_check_pipe(struct file * pipe)219 static 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
autofs_set_packet_pipe_flags(struct file * pipe)230 static 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
autofs_prepare_pipe(struct file * pipe)238 static 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
249 int autofs_wait(struct autofs_sb_info *,
250 const struct path *, enum autofs_notify);
251 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
252 void autofs_catatonic_mode(struct autofs_sb_info *);
253
autofs_get_dev(struct autofs_sb_info * sbi)254 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)
255 {
256 return new_encode_dev(sbi->sb->s_dev);
257 }
258
autofs_get_ino(struct autofs_sb_info * sbi)259 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi)
260 {
261 return d_inode(sbi->sb->s_root)->i_ino;
262 }
263
__autofs_add_expiring(struct dentry * dentry)264 static inline void __autofs_add_expiring(struct dentry *dentry)
265 {
266 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
267 struct autofs_info *ino = autofs_dentry_ino(dentry);
268
269 if (ino) {
270 if (list_empty(&ino->expiring))
271 list_add(&ino->expiring, &sbi->expiring_list);
272 }
273 }
274
autofs_add_expiring(struct dentry * dentry)275 static inline void autofs_add_expiring(struct dentry *dentry)
276 {
277 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
278 struct autofs_info *ino = autofs_dentry_ino(dentry);
279
280 if (ino) {
281 spin_lock(&sbi->lookup_lock);
282 if (list_empty(&ino->expiring))
283 list_add(&ino->expiring, &sbi->expiring_list);
284 spin_unlock(&sbi->lookup_lock);
285 }
286 }
287
autofs_del_expiring(struct dentry * dentry)288 static inline void autofs_del_expiring(struct dentry *dentry)
289 {
290 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
291 struct autofs_info *ino = autofs_dentry_ino(dentry);
292
293 if (ino) {
294 spin_lock(&sbi->lookup_lock);
295 if (!list_empty(&ino->expiring))
296 list_del_init(&ino->expiring);
297 spin_unlock(&sbi->lookup_lock);
298 }
299 }
300
301 void autofs_kill_sb(struct super_block *);
302