1 /*
2 * Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
3 * Copyright 2005-2006 Ian Kent <raven@themaw.net>
4 *
5 * This file is part of the Linux kernel and is made available under
6 * the terms of the GNU General Public License, version 2, or at your
7 * option, any later version, incorporated herein by reference.
8 */
9
10 /* Internal header file for autofs */
11
12 #include <linux/auto_fs4.h>
13 #include <linux/auto_dev-ioctl.h>
14 #include <linux/mutex.h>
15 #include <linux/spinlock.h>
16 #include <linux/list.h>
17
18 /* This is the range of ioctl() numbers we claim as ours */
19 #define AUTOFS_IOC_FIRST AUTOFS_IOC_READY
20 #define AUTOFS_IOC_COUNT 32
21
22 #define AUTOFS_DEV_IOCTL_IOC_FIRST (AUTOFS_DEV_IOCTL_VERSION)
23 #define AUTOFS_DEV_IOCTL_IOC_COUNT \
24 (AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD)
25
26 #include <linux/kernel.h>
27 #include <linux/slab.h>
28 #include <linux/time.h>
29 #include <linux/string.h>
30 #include <linux/wait.h>
31 #include <linux/sched.h>
32 #include <linux/mount.h>
33 #include <linux/namei.h>
34 #include <asm/current.h>
35 #include <linux/uaccess.h>
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 /*
43 * Unified info structure. This is pointed to by both the dentry and
44 * inode structures. Each file in the filesystem has an instance of this
45 * structure. It holds a reference to the dentry, so dentries are never
46 * flushed while the file exists. All name lookups are dealt with at the
47 * dentry level, although the filesystem can interfere in the validation
48 * process. Readdir is implemented by traversing the dentry lists.
49 */
50 struct autofs_info {
51 struct dentry *dentry;
52 struct inode *inode;
53
54 int flags;
55
56 struct completion expire_complete;
57
58 struct list_head active;
59 int active_count;
60
61 struct list_head expiring;
62
63 struct autofs_sb_info *sbi;
64 unsigned long last_used;
65 atomic_t count;
66
67 kuid_t uid;
68 kgid_t gid;
69 };
70
71 #define AUTOFS_INF_EXPIRING (1<<0) /* dentry in the process of expiring */
72 #define AUTOFS_INF_WANT_EXPIRE (1<<1) /* the dentry is being considered
73 * for expiry, so RCU_walk is
74 * not permitted. If it progresses to
75 * actual expiry attempt, the flag is
76 * not cleared when EXPIRING is set -
77 * in that case it gets cleared only
78 * when it comes to clearing EXPIRING.
79 */
80 #define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */
81
82 struct autofs_wait_queue {
83 wait_queue_head_t queue;
84 struct autofs_wait_queue *next;
85 autofs_wqt_t wait_queue_token;
86 /* We use the following to see what we are waiting for */
87 struct qstr name;
88 u32 dev;
89 u64 ino;
90 kuid_t uid;
91 kgid_t gid;
92 pid_t pid;
93 pid_t tgid;
94 /* This is for status reporting upon return */
95 int status;
96 unsigned int wait_ctr;
97 };
98
99 #define AUTOFS_SBI_MAGIC 0x6d4a556d
100
101 struct autofs_sb_info {
102 u32 magic;
103 int pipefd;
104 struct file *pipe;
105 struct pid *oz_pgrp;
106 int catatonic;
107 int version;
108 int sub_version;
109 int min_proto;
110 int max_proto;
111 unsigned long exp_timeout;
112 unsigned int type;
113 struct super_block *sb;
114 struct mutex wq_mutex;
115 struct mutex pipe_mutex;
116 spinlock_t fs_lock;
117 struct autofs_wait_queue *queues; /* Wait queue pointer */
118 spinlock_t lookup_lock;
119 struct list_head active_list;
120 struct list_head expiring_list;
121 struct rcu_head rcu;
122 };
123
autofs4_sbi(struct super_block * sb)124 static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
125 {
126 return (struct autofs_sb_info *)(sb->s_fs_info);
127 }
128
autofs4_dentry_ino(struct dentry * dentry)129 static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
130 {
131 return (struct autofs_info *)(dentry->d_fsdata);
132 }
133
134 /* autofs4_oz_mode(): do we see the man behind the curtain? (The
135 * processes which do manipulations for us in user space sees the raw
136 * filesystem without "magic".)
137 */
autofs4_oz_mode(struct autofs_sb_info * sbi)138 static inline int autofs4_oz_mode(struct autofs_sb_info *sbi)
139 {
140 return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
141 }
142
143 struct inode *autofs4_get_inode(struct super_block *, umode_t);
144 void autofs4_free_ino(struct autofs_info *);
145
146 /* Expiration */
147 int is_autofs4_dentry(struct dentry *);
148 int autofs4_expire_wait(struct dentry *dentry, int rcu_walk);
149 int autofs4_expire_run(struct super_block *, struct vfsmount *,
150 struct autofs_sb_info *,
151 struct autofs_packet_expire __user *);
152 int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
153 struct autofs_sb_info *sbi, int when);
154 int autofs4_expire_multi(struct super_block *, struct vfsmount *,
155 struct autofs_sb_info *, int __user *);
156 struct dentry *autofs4_expire_direct(struct super_block *sb,
157 struct vfsmount *mnt,
158 struct autofs_sb_info *sbi, int how);
159 struct dentry *autofs4_expire_indirect(struct super_block *sb,
160 struct vfsmount *mnt,
161 struct autofs_sb_info *sbi, int how);
162
163 /* Device node initialization */
164
165 int autofs_dev_ioctl_init(void);
166 void autofs_dev_ioctl_exit(void);
167
168 /* Operations structures */
169
170 extern const struct inode_operations autofs4_symlink_inode_operations;
171 extern const struct inode_operations autofs4_dir_inode_operations;
172 extern const struct file_operations autofs4_dir_operations;
173 extern const struct file_operations autofs4_root_operations;
174 extern const struct dentry_operations autofs4_dentry_operations;
175
176 /* VFS automount flags management functions */
__managed_dentry_set_managed(struct dentry * dentry)177 static inline void __managed_dentry_set_managed(struct dentry *dentry)
178 {
179 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
180 }
181
managed_dentry_set_managed(struct dentry * dentry)182 static inline void managed_dentry_set_managed(struct dentry *dentry)
183 {
184 spin_lock(&dentry->d_lock);
185 __managed_dentry_set_managed(dentry);
186 spin_unlock(&dentry->d_lock);
187 }
188
__managed_dentry_clear_managed(struct dentry * dentry)189 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
190 {
191 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
192 }
193
managed_dentry_clear_managed(struct dentry * dentry)194 static inline void managed_dentry_clear_managed(struct dentry *dentry)
195 {
196 spin_lock(&dentry->d_lock);
197 __managed_dentry_clear_managed(dentry);
198 spin_unlock(&dentry->d_lock);
199 }
200
201 /* Initializing function */
202
203 int autofs4_fill_super(struct super_block *, void *, int);
204 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *);
205 void autofs4_clean_ino(struct autofs_info *);
206
autofs_prepare_pipe(struct file * pipe)207 static inline int autofs_prepare_pipe(struct file *pipe)
208 {
209 if (!(pipe->f_mode & FMODE_CAN_WRITE))
210 return -EINVAL;
211 if (!S_ISFIFO(file_inode(pipe)->i_mode))
212 return -EINVAL;
213 /* We want a packet pipe */
214 pipe->f_flags |= O_DIRECT;
215 return 0;
216 }
217
218 /* Queue management functions */
219
220 int autofs4_wait(struct autofs_sb_info *, struct dentry *, enum autofs_notify);
221 int autofs4_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
222 void autofs4_catatonic_mode(struct autofs_sb_info *);
223
autofs4_get_dev(struct autofs_sb_info * sbi)224 static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
225 {
226 return new_encode_dev(sbi->sb->s_dev);
227 }
228
autofs4_get_ino(struct autofs_sb_info * sbi)229 static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
230 {
231 return d_inode(sbi->sb->s_root)->i_ino;
232 }
233
__autofs4_add_expiring(struct dentry * dentry)234 static inline void __autofs4_add_expiring(struct dentry *dentry)
235 {
236 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
237 struct autofs_info *ino = autofs4_dentry_ino(dentry);
238
239 if (ino) {
240 if (list_empty(&ino->expiring))
241 list_add(&ino->expiring, &sbi->expiring_list);
242 }
243 }
244
autofs4_add_expiring(struct dentry * dentry)245 static inline void autofs4_add_expiring(struct dentry *dentry)
246 {
247 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
248 struct autofs_info *ino = autofs4_dentry_ino(dentry);
249
250 if (ino) {
251 spin_lock(&sbi->lookup_lock);
252 if (list_empty(&ino->expiring))
253 list_add(&ino->expiring, &sbi->expiring_list);
254 spin_unlock(&sbi->lookup_lock);
255 }
256 }
257
autofs4_del_expiring(struct dentry * dentry)258 static inline void autofs4_del_expiring(struct dentry *dentry)
259 {
260 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
261 struct autofs_info *ino = autofs4_dentry_ino(dentry);
262
263 if (ino) {
264 spin_lock(&sbi->lookup_lock);
265 if (!list_empty(&ino->expiring))
266 list_del_init(&ino->expiring);
267 spin_unlock(&sbi->lookup_lock);
268 }
269 }
270
271 void autofs4_kill_sb(struct super_block *);
272