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         int active_count;
  62
  63         struct list_head expiring;
  64
  65         struct autofs_sb_info *sbi;
  66         unsigned long last_used;
  67         atomic_t 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 struct autofs_wait_queue {
  86         wait_queue_head_t queue;
  87         struct autofs_wait_queue *next;
  88         autofs_wqt_t wait_queue_token;
  89         /* We use the following to see what we are waiting for */
  90         struct qstr name;
  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
 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
 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  */
 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 */
 179 static inline void __managed_dentry_set_managed(struct dentry *dentry)
 180 {
 181         dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 182 }
 183
 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
 191 static inline void __managed_dentry_clear_managed(struct dentry *dentry)
 192 {
 193         dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
 194 }
 195
 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
 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
 229 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)
 230 {
 231         return new_encode_dev(sbi->sb->s_dev);
 232 }
 233
 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
 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
 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
 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 *);