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
29 /* This is the range of ioctl() numbers we claim as ours */
30 #define AUTOFS_IOC_FIRST AUTOFS_IOC_READY
31 #define AUTOFS_IOC_COUNT 32
32
33 #define AUTOFS_DEV_IOCTL_IOC_FIRST (AUTOFS_DEV_IOCTL_VERSION)
34 #define AUTOFS_DEV_IOCTL_IOC_COUNT \
35 (AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD)
36
37 #ifdef pr_fmt
38 #undef pr_fmt
39 #endif
40 #define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__
41
42 extern struct file_system_type autofs_fs_type;
43
44 /*
45 * Unified info structure. This is pointed to by both the dentry and
46 * inode structures. Each file in the filesystem has an instance of this
47 * structure. It holds a reference to the dentry, so dentries are never
48 * flushed while the file exists. All name lookups are dealt with at the
49 * dentry level, although the filesystem can interfere in the validation
50 * process. Readdir is implemented by traversing the dentry lists.
51 */
52 struct autofs_info {
53 struct dentry *dentry;
54 struct inode *inode;
55
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
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 */
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
108 struct 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
autofs_sbi(struct super_block * sb)131 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
132 {
133 return (struct autofs_sb_info *)(sb->s_fs_info);
134 }
135
autofs_dentry_ino(struct dentry * dentry)136 static 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 */
autofs_oz_mode(struct autofs_sb_info * sbi)145 static 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
151 struct inode *autofs_get_inode(struct super_block *, umode_t);
152 void autofs_free_ino(struct autofs_info *);
153
154 /* Expiration */
155 int is_autofs_dentry(struct dentry *);
156 int autofs_expire_wait(const struct path *path, int rcu_walk);
157 int autofs_expire_run(struct super_block *, struct vfsmount *,
158 struct autofs_sb_info *,
159 struct autofs_packet_expire __user *);
160 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
161 struct autofs_sb_info *sbi, unsigned int how);
162 int autofs_expire_multi(struct super_block *, struct vfsmount *,
163 struct autofs_sb_info *, int __user *);
164
165 /* Device node initialization */
166
167 int autofs_dev_ioctl_init(void);
168 void autofs_dev_ioctl_exit(void);
169
170 /* Operations structures */
171
172 extern const struct inode_operations autofs_symlink_inode_operations;
173 extern const struct inode_operations autofs_dir_inode_operations;
174 extern const struct file_operations autofs_dir_operations;
175 extern const struct file_operations autofs_root_operations;
176 extern const struct dentry_operations autofs_dentry_operations;
177
178 /* VFS automount flags management functions */
__managed_dentry_set_managed(struct dentry * dentry)179 static inline void __managed_dentry_set_managed(struct dentry *dentry)
180 {
181 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
182 }
183
managed_dentry_set_managed(struct dentry * dentry)184 static inline void managed_dentry_set_managed(struct dentry *dentry)
185 {
186 spin_lock(&dentry->d_lock);
187 __managed_dentry_set_managed(dentry);
188 spin_unlock(&dentry->d_lock);
189 }
190
__managed_dentry_clear_managed(struct dentry * dentry)191 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
192 {
193 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
194 }
195
managed_dentry_clear_managed(struct dentry * dentry)196 static inline void managed_dentry_clear_managed(struct dentry *dentry)
197 {
198 spin_lock(&dentry->d_lock);
199 __managed_dentry_clear_managed(dentry);
200 spin_unlock(&dentry->d_lock);
201 }
202
203 /* Initializing function */
204
205 int autofs_fill_super(struct super_block *, void *, int);
206 struct autofs_info *autofs_new_ino(struct autofs_sb_info *);
207 void autofs_clean_ino(struct autofs_info *);
208
autofs_prepare_pipe(struct file * pipe)209 static inline int autofs_prepare_pipe(struct file *pipe)
210 {
211 if (!(pipe->f_mode & FMODE_CAN_WRITE))
212 return -EINVAL;
213 if (!S_ISFIFO(file_inode(pipe)->i_mode))
214 return -EINVAL;
215 /* We want a packet pipe */
216 pipe->f_flags |= O_DIRECT;
217 /* We don't expect -EAGAIN */
218 pipe->f_flags &= ~O_NONBLOCK;
219 return 0;
220 }
221
222 /* Queue management functions */
223
224 int autofs_wait(struct autofs_sb_info *,
225 const struct path *, enum autofs_notify);
226 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
227 void autofs_catatonic_mode(struct autofs_sb_info *);
228
autofs_get_dev(struct autofs_sb_info * sbi)229 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)
230 {
231 return new_encode_dev(sbi->sb->s_dev);
232 }
233
autofs_get_ino(struct autofs_sb_info * sbi)234 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi)
235 {
236 return d_inode(sbi->sb->s_root)->i_ino;
237 }
238
__autofs_add_expiring(struct dentry * dentry)239 static inline void __autofs_add_expiring(struct dentry *dentry)
240 {
241 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
242 struct autofs_info *ino = autofs_dentry_ino(dentry);
243
244 if (ino) {
245 if (list_empty(&ino->expiring))
246 list_add(&ino->expiring, &sbi->expiring_list);
247 }
248 }
249
autofs_add_expiring(struct dentry * dentry)250 static inline void autofs_add_expiring(struct dentry *dentry)
251 {
252 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
253 struct autofs_info *ino = autofs_dentry_ino(dentry);
254
255 if (ino) {
256 spin_lock(&sbi->lookup_lock);
257 if (list_empty(&ino->expiring))
258 list_add(&ino->expiring, &sbi->expiring_list);
259 spin_unlock(&sbi->lookup_lock);
260 }
261 }
262
autofs_del_expiring(struct dentry * dentry)263 static inline void autofs_del_expiring(struct dentry *dentry)
264 {
265 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
266 struct autofs_info *ino = autofs_dentry_ino(dentry);
267
268 if (ino) {
269 spin_lock(&sbi->lookup_lock);
270 if (!list_empty(&ino->expiring))
271 list_del_init(&ino->expiring);
272 spin_unlock(&sbi->lookup_lock);
273 }
274 }
275
276 void autofs_kill_sb(struct super_block *);
277