tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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 <uapi/linux/mount.h>
20#include <linux/mount.h>
21#include <linux/namei.h>
22#include <linux/uaccess.h>
23#include <linux/mutex.h>
24#include <linux/spinlock.h>
25#include <linux/list.h>
26#include <linux/completion.h>
27#include <linux/file.h>
28#include <linux/magic.h>
29#include <linux/fs_context.h>
30#include <linux/fs_parser.h>
31#include "../mount.h"
32#include <linux/ns_common.h>
33
34
35/* This is the range of ioctl() numbers we claim as ours */
36#define AUTOFS_IOC_FIRST AUTOFS_IOC_READY
37#define AUTOFS_IOC_COUNT 32
38
39#define AUTOFS_DEV_IOCTL_IOC_FIRST (AUTOFS_DEV_IOCTL_VERSION)
40#define AUTOFS_DEV_IOCTL_IOC_COUNT \
41 (AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD)
42
43#ifdef pr_fmt
44#undef pr_fmt
45#endif
46#define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__
47
48extern struct file_system_type autofs_fs_type;
49
50/*
51 * Unified info structure. This is pointed to by both the dentry and
52 * inode structures. Each file in the filesystem has an instance of this
53 * structure. It holds a reference to the dentry, so dentries are never
54 * flushed while the file exists. All name lookups are dealt with at the
55 * dentry level, although the filesystem can interfere in the validation
56 * process. Readdir is implemented by traversing the dentry lists.
57 */
58struct autofs_info {
59 struct dentry *dentry;
60 int flags;
61
62 struct completion expire_complete;
63
64 struct list_head active;
65
66 struct list_head expiring;
67
68 struct autofs_sb_info *sbi;
69 unsigned long exp_timeout;
70 unsigned long last_used;
71 int count;
72
73 kuid_t uid;
74 kgid_t gid;
75 struct rcu_head rcu;
76};
77
78#define AUTOFS_INF_EXPIRING (1<<0) /* dentry in the process of expiring */
79#define AUTOFS_INF_WANT_EXPIRE (1<<1) /* the dentry is being considered
80 * for expiry, so RCU_walk is
81 * not permitted. If it progresses to
82 * actual expiry attempt, the flag is
83 * not cleared when EXPIRING is set -
84 * in that case it gets cleared only
85 * when it comes to clearing EXPIRING.
86 */
87#define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */
88
89#define AUTOFS_INF_EXPIRE_SET (1<<3) /* per-dentry expire timeout set for
90 this mount point.
91 */
92struct autofs_wait_queue {
93 wait_queue_head_t queue;
94 struct autofs_wait_queue *next;
95 autofs_wqt_t wait_queue_token;
96 /* We use the following to see what we are waiting for */
97 struct qstr name;
98 u32 offset;
99 u32 dev;
100 u64 ino;
101 kuid_t uid;
102 kgid_t gid;
103 pid_t pid;
104 pid_t tgid;
105 /* This is for status reporting upon return */
106 int status;
107 unsigned int wait_ctr;
108};
109
110#define AUTOFS_SBI_MAGIC 0x6d4a556d
111
112#define AUTOFS_SBI_CATATONIC 0x0001
113#define AUTOFS_SBI_STRICTEXPIRE 0x0002
114#define AUTOFS_SBI_IGNORE 0x0004
115
116struct autofs_sb_info {
117 u32 magic;
118 int pipefd;
119 struct file *pipe;
120 struct pid *oz_pgrp;
121 u64 mnt_ns_id;
122 int version;
123 int sub_version;
124 int min_proto;
125 int max_proto;
126 unsigned int flags;
127 unsigned long exp_timeout;
128 unsigned int type;
129 struct super_block *sb;
130 struct mutex wq_mutex;
131 struct mutex pipe_mutex;
132 spinlock_t fs_lock;
133 struct autofs_wait_queue *queues; /* Wait queue pointer */
134 spinlock_t lookup_lock;
135 struct list_head active_list;
136 struct list_head expiring_list;
137 struct rcu_head rcu;
138};
139
140static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
141{
142 return (struct autofs_sb_info *)(sb->s_fs_info);
143}
144
145static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry)
146{
147 return (struct autofs_info *)(dentry->d_fsdata);
148}
149
150/* autofs_oz_mode(): do we see the man behind the curtain? (The
151 * processes which do manipulations for us in user space sees the raw
152 * filesystem without "magic".)
153 */
154static inline int autofs_oz_mode(struct autofs_sb_info *sbi)
155{
156 return ((sbi->flags & AUTOFS_SBI_CATATONIC) ||
157 task_pgrp(current) == sbi->oz_pgrp);
158}
159
160static inline bool autofs_empty(struct autofs_info *ino)
161{
162 return ino->count < 2;
163}
164
165struct inode *autofs_get_inode(struct super_block *, umode_t);
166void autofs_free_ino(struct autofs_info *);
167
168/* Expiration */
169int is_autofs_dentry(struct dentry *);
170int autofs_expire_wait(const struct path *path, int rcu_walk);
171int autofs_expire_run(struct super_block *, struct vfsmount *,
172 struct autofs_sb_info *,
173 struct autofs_packet_expire __user *);
174int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
175 struct autofs_sb_info *sbi, unsigned int how);
176int autofs_expire_multi(struct super_block *, struct vfsmount *,
177 struct autofs_sb_info *, int __user *);
178
179/* Device node initialization */
180
181int autofs_dev_ioctl_init(void);
182void autofs_dev_ioctl_exit(void);
183
184/* Operations structures */
185
186extern const struct inode_operations autofs_symlink_inode_operations;
187extern const struct inode_operations autofs_dir_inode_operations;
188extern const struct file_operations autofs_dir_operations;
189extern const struct file_operations autofs_root_operations;
190extern const struct dentry_operations autofs_dentry_operations;
191
192/* VFS automount flags management functions */
193static inline void __managed_dentry_set_managed(struct dentry *dentry)
194{
195 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
196}
197
198static inline void managed_dentry_set_managed(struct dentry *dentry)
199{
200 spin_lock(&dentry->d_lock);
201 __managed_dentry_set_managed(dentry);
202 spin_unlock(&dentry->d_lock);
203}
204
205static inline void __managed_dentry_clear_managed(struct dentry *dentry)
206{
207 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
208}
209
210static inline void managed_dentry_clear_managed(struct dentry *dentry)
211{
212 spin_lock(&dentry->d_lock);
213 __managed_dentry_clear_managed(dentry);
214 spin_unlock(&dentry->d_lock);
215}
216
217/* Initializing function */
218
219extern const struct fs_parameter_spec autofs_param_specs[];
220int autofs_init_fs_context(struct fs_context *fc);
221struct autofs_info *autofs_new_ino(struct autofs_sb_info *);
222void autofs_clean_ino(struct autofs_info *);
223
224static inline int autofs_check_pipe(struct file *pipe)
225{
226 if (pipe->f_mode & FMODE_PATH)
227 return -EINVAL;
228 if (!(pipe->f_mode & FMODE_CAN_WRITE))
229 return -EINVAL;
230 if (!S_ISFIFO(file_inode(pipe)->i_mode))
231 return -EINVAL;
232 return 0;
233}
234
235static inline void autofs_set_packet_pipe_flags(struct file *pipe)
236{
237 /* We want a packet pipe */
238 pipe->f_flags |= O_DIRECT;
239 /* We don't expect -EAGAIN */
240 pipe->f_flags &= ~O_NONBLOCK;
241}
242
243static inline int autofs_prepare_pipe(struct file *pipe)
244{
245 int ret = autofs_check_pipe(pipe);
246 if (ret < 0)
247 return ret;
248 autofs_set_packet_pipe_flags(pipe);
249 return 0;
250}
251
252/* Queue management functions */
253
254int autofs_wait(struct autofs_sb_info *,
255 const struct path *, enum autofs_notify);
256int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
257void autofs_catatonic_mode(struct autofs_sb_info *);
258
259static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)
260{
261 return new_encode_dev(sbi->sb->s_dev);
262}
263
264static inline u64 autofs_get_ino(struct autofs_sb_info *sbi)
265{
266 return d_inode(sbi->sb->s_root)->i_ino;
267}
268
269static inline void __autofs_add_expiring(struct dentry *dentry)
270{
271 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
272 struct autofs_info *ino = autofs_dentry_ino(dentry);
273
274 if (ino) {
275 if (list_empty(&ino->expiring))
276 list_add(&ino->expiring, &sbi->expiring_list);
277 }
278}
279
280static inline void autofs_add_expiring(struct dentry *dentry)
281{
282 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
283 struct autofs_info *ino = autofs_dentry_ino(dentry);
284
285 if (ino) {
286 spin_lock(&sbi->lookup_lock);
287 if (list_empty(&ino->expiring))
288 list_add(&ino->expiring, &sbi->expiring_list);
289 spin_unlock(&sbi->lookup_lock);
290 }
291}
292
293static inline void autofs_del_expiring(struct dentry *dentry)
294{
295 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
296 struct autofs_info *ino = autofs_dentry_ino(dentry);
297
298 if (ino) {
299 spin_lock(&sbi->lookup_lock);
300 if (!list_empty(&ino->expiring))
301 list_del_init(&ino->expiring);
302 spin_unlock(&sbi->lookup_lock);
303 }
304}
305
306void autofs_kill_sb(struct super_block *);