fs/autofs/autofs_i.h

   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 dev;
  91         u64 ino;
  92         kuid_t uid;
  93         kgid_t gid;
  94         pid_t pid;
  95         pid_t tgid;
  96         /* This is for status reporting upon return */
  97         int status;
  98         unsigned int wait_ctr;
  99 };
 100
 101 #define AUTOFS_SBI_MAGIC 0x6d4a556d
 102
 103 #define AUTOFS_SBI_CATATONIC    0x0001
 104 #define AUTOFS_SBI_STRICTEXPIRE 0x0002
 105 #define AUTOFS_SBI_IGNORE       0x0004
 106
 107 struct autofs_sb_info {
 108         u32 magic;
 109         int pipefd;
 110         struct file *pipe;
 111         struct pid *oz_pgrp;
 112         int version;
 113         int sub_version;
 114         int min_proto;
 115         int max_proto;
 116         unsigned int flags;
 117         unsigned long exp_timeout;
 118         unsigned int type;
 119         struct super_block *sb;
 120         struct mutex wq_mutex;
 121         struct mutex pipe_mutex;
 122         spinlock_t fs_lock;
 123         struct autofs_wait_queue *queues; /* Wait queue pointer */
 124         spinlock_t lookup_lock;
 125         struct list_head active_list;
 126         struct list_head expiring_list;
 127         struct rcu_head rcu;
 128 };
 129
 130 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
 131 {
 132         return (struct autofs_sb_info *)(sb->s_fs_info);
 133 }
 134
 135 static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry)
 136 {
 137         return (struct autofs_info *)(dentry->d_fsdata);
 138 }
 139
 140 /* autofs_oz_mode(): do we see the man behind the curtain?  (The
 141  * processes which do manipulations for us in user space sees the raw
 142  * filesystem without "magic".)
 143  */
 144 static inline int autofs_oz_mode(struct autofs_sb_info *sbi)
 145 {
 146         return ((sbi->flags & AUTOFS_SBI_CATATONIC) ||
 147                  task_pgrp(current) == sbi->oz_pgrp);
 148 }
 149
 150 struct inode *autofs_get_inode(struct super_block *, umode_t);
 151 void autofs_free_ino(struct autofs_info *);
 152
 153 /* Expiration */
 154 int is_autofs_dentry(struct dentry *);
 155 int autofs_expire_wait(const struct path *path, int rcu_walk);
 156 int autofs_expire_run(struct super_block *, struct vfsmount *,
 157                       struct autofs_sb_info *,
 158                       struct autofs_packet_expire __user *);
 159 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 160                            struct autofs_sb_info *sbi, unsigned int how);
 161 int autofs_expire_multi(struct super_block *, struct vfsmount *,
 162                         struct autofs_sb_info *, int __user *);
 163
 164 /* Device node initialization */
 165
 166 int autofs_dev_ioctl_init(void);
 167 void autofs_dev_ioctl_exit(void);
 168
 169 /* Operations structures */
 170
 171 extern const struct inode_operations autofs_symlink_inode_operations;
 172 extern const struct inode_operations autofs_dir_inode_operations;
 173 extern const struct file_operations autofs_dir_operations;
 174 extern const struct file_operations autofs_root_operations;
 175 extern const struct dentry_operations autofs_dentry_operations;
 176
 177 /* VFS automount flags management functions */
 178 static inline void __managed_dentry_set_managed(struct dentry *dentry)
 179 {
 180         dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 181 }
 182
 183 static inline void managed_dentry_set_managed(struct dentry *dentry)
 184 {
 185         spin_lock(&dentry->d_lock);
 186         __managed_dentry_set_managed(dentry);
 187         spin_unlock(&dentry->d_lock);
 188 }
 189
 190 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
 191 {
 192         dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 193 }
 194
 195 static inline void managed_dentry_clear_managed(struct dentry *dentry)
 196 {
 197         spin_lock(&dentry->d_lock);
 198         __managed_dentry_clear_managed(dentry);
 199         spin_unlock(&dentry->d_lock);
 200 }
 201
 202 /* Initializing function */
 203
 204 int autofs_fill_super(struct super_block *, void *, int);
 205 struct autofs_info *autofs_new_ino(struct autofs_sb_info *);
 206 void autofs_clean_ino(struct autofs_info *);
 207
 208 static inline int autofs_prepare_pipe(struct file *pipe)
 209 {
 210         if (!(pipe->f_mode & FMODE_CAN_WRITE))
 211                 return -EINVAL;
 212         if (!S_ISFIFO(file_inode(pipe)->i_mode))
 213                 return -EINVAL;
 214         /* We want a packet pipe */
 215         pipe->f_flags |= O_DIRECT;
 216         /* We don't expect -EAGAIN */
 217         pipe->f_flags &= ~O_NONBLOCK;
 218         return 0;
 219 }
 220
 221 /* Queue management functions */
 222
 223 int autofs_wait(struct autofs_sb_info *,
 224                  const struct path *, enum autofs_notify);
 225 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
 226 void autofs_catatonic_mode(struct autofs_sb_info *);
 227
 228 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)
 229 {
 230         return new_encode_dev(sbi->sb->s_dev);
 231 }
 232
 233 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi)
 234 {
 235         return d_inode(sbi->sb->s_root)->i_ino;
 236 }
 237
 238 static inline void __autofs_add_expiring(struct dentry *dentry)
 239 {
 240         struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
 241         struct autofs_info *ino = autofs_dentry_ino(dentry);
 242
 243         if (ino) {
 244                 if (list_empty(&ino->expiring))
 245                         list_add(&ino->expiring, &sbi->expiring_list);
 246         }
 247 }
 248
 249 static inline void autofs_add_expiring(struct dentry *dentry)
 250 {
 251         struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
 252         struct autofs_info *ino = autofs_dentry_ino(dentry);
 253
 254         if (ino) {
 255                 spin_lock(&sbi->lookup_lock);
 256                 if (list_empty(&ino->expiring))
 257                         list_add(&ino->expiring, &sbi->expiring_list);
 258                 spin_unlock(&sbi->lookup_lock);
 259         }
 260 }
 261
 262 static inline void autofs_del_expiring(struct dentry *dentry)
 263 {
 264         struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
 265         struct autofs_info *ino = autofs_dentry_ino(dentry);
 266
 267         if (ino) {
 268                 spin_lock(&sbi->lookup_lock);
 269                 if (!list_empty(&ino->expiring))
 270                         list_del_init(&ino->expiring);
 271                 spin_unlock(&sbi->lookup_lock);
 272         }
 273 }
 274
 275 void autofs_kill_sb(struct super_block *);