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 int flags; 55 56 struct completion expire_complete; 57 58 struct list_head active; 59 60 struct list_head expiring; 61 62 struct autofs_sb_info *sbi; 63 unsigned long last_used; 64 int count; 65 66 kuid_t uid; 67 kgid_t gid; 68 struct rcu_head rcu; 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 offset; 89 u32 dev; 90 u64 ino; 91 kuid_t uid; 92 kgid_t gid; 93 pid_t pid; 94 pid_t tgid; 95 /* This is for status reporting upon return */ 96 int status; 97 unsigned int wait_ctr; 98 }; 99 100 #define AUTOFS_SBI_MAGIC 0x6d4a556d 101 102 #define AUTOFS_SBI_CATATONIC 0x0001 103 #define AUTOFS_SBI_STRICTEXPIRE 0x0002 104 #define AUTOFS_SBI_IGNORE 0x0004 105 106 struct autofs_sb_info { 107 u32 magic; 108 int pipefd; 109 struct file *pipe; 110 struct pid *oz_pgrp; 111 int version; 112 int sub_version; 113 int min_proto; 114 int max_proto; 115 unsigned int flags; 116 unsigned long exp_timeout; 117 unsigned int type; 118 struct super_block *sb; 119 struct mutex wq_mutex; 120 struct mutex pipe_mutex; 121 spinlock_t fs_lock; 122 struct autofs_wait_queue *queues; /* Wait queue pointer */ 123 spinlock_t lookup_lock; 124 struct list_head active_list; 125 struct list_head expiring_list; 126 struct rcu_head rcu; 127 }; 128 129 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb) 130 { 131 return (struct autofs_sb_info *)(sb->s_fs_info); 132 } 133 134 static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry) 135 { 136 return (struct autofs_info *)(dentry->d_fsdata); 137 } 138 139 /* autofs_oz_mode(): do we see the man behind the curtain? (The 140 * processes which do manipulations for us in user space sees the raw 141 * filesystem without "magic".) 142 */ 143 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) 144 { 145 return ((sbi->flags & AUTOFS_SBI_CATATONIC) || 146 task_pgrp(current) == sbi->oz_pgrp); 147 } 148 149 static inline bool autofs_empty(struct autofs_info *ino) 150 { 151 return ino->count < 2; 152 } 153 154 struct inode *autofs_get_inode(struct super_block *, umode_t); 155 void autofs_free_ino(struct autofs_info *); 156 157 /* Expiration */ 158 int is_autofs_dentry(struct dentry *); 159 int autofs_expire_wait(const struct path *path, int rcu_walk); 160 int autofs_expire_run(struct super_block *, struct vfsmount *, 161 struct autofs_sb_info *, 162 struct autofs_packet_expire __user *); 163 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, 164 struct autofs_sb_info *sbi, unsigned int how); 165 int autofs_expire_multi(struct super_block *, struct vfsmount *, 166 struct autofs_sb_info *, int __user *); 167 168 /* Device node initialization */ 169 170 int autofs_dev_ioctl_init(void); 171 void autofs_dev_ioctl_exit(void); 172 173 /* Operations structures */ 174 175 extern const struct inode_operations autofs_symlink_inode_operations; 176 extern const struct inode_operations autofs_dir_inode_operations; 177 extern const struct file_operations autofs_dir_operations; 178 extern const struct file_operations autofs_root_operations; 179 extern const struct dentry_operations autofs_dentry_operations; 180 181 /* VFS automount flags management functions */ 182 static inline void __managed_dentry_set_managed(struct dentry *dentry) 183 { 184 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 185 } 186 187 static inline void managed_dentry_set_managed(struct dentry *dentry) 188 { 189 spin_lock(&dentry->d_lock); 190 __managed_dentry_set_managed(dentry); 191 spin_unlock(&dentry->d_lock); 192 } 193 194 static inline void __managed_dentry_clear_managed(struct dentry *dentry) 195 { 196 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 197 } 198 199 static inline void managed_dentry_clear_managed(struct dentry *dentry) 200 { 201 spin_lock(&dentry->d_lock); 202 __managed_dentry_clear_managed(dentry); 203 spin_unlock(&dentry->d_lock); 204 } 205 206 /* Initializing function */ 207 208 int autofs_fill_super(struct super_block *, void *, int); 209 struct autofs_info *autofs_new_ino(struct autofs_sb_info *); 210 void autofs_clean_ino(struct autofs_info *); 211 212 static inline int autofs_prepare_pipe(struct file *pipe) 213 { 214 if (!(pipe->f_mode & FMODE_CAN_WRITE)) 215 return -EINVAL; 216 if (!S_ISFIFO(file_inode(pipe)->i_mode)) 217 return -EINVAL; 218 /* We want a packet pipe */ 219 pipe->f_flags |= O_DIRECT; 220 /* We don't expect -EAGAIN */ 221 pipe->f_flags &= ~O_NONBLOCK; 222 return 0; 223 } 224 225 /* Queue management functions */ 226 227 int autofs_wait(struct autofs_sb_info *, 228 const struct path *, enum autofs_notify); 229 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int); 230 void autofs_catatonic_mode(struct autofs_sb_info *); 231 232 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi) 233 { 234 return new_encode_dev(sbi->sb->s_dev); 235 } 236 237 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi) 238 { 239 return d_inode(sbi->sb->s_root)->i_ino; 240 } 241 242 static inline void __autofs_add_expiring(struct dentry *dentry) 243 { 244 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 245 struct autofs_info *ino = autofs_dentry_ino(dentry); 246 247 if (ino) { 248 if (list_empty(&ino->expiring)) 249 list_add(&ino->expiring, &sbi->expiring_list); 250 } 251 } 252 253 static inline void autofs_add_expiring(struct dentry *dentry) 254 { 255 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 256 struct autofs_info *ino = autofs_dentry_ino(dentry); 257 258 if (ino) { 259 spin_lock(&sbi->lookup_lock); 260 if (list_empty(&ino->expiring)) 261 list_add(&ino->expiring, &sbi->expiring_list); 262 spin_unlock(&sbi->lookup_lock); 263 } 264 } 265 266 static inline void autofs_del_expiring(struct dentry *dentry) 267 { 268 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 269 struct autofs_info *ino = autofs_dentry_ino(dentry); 270 271 if (ino) { 272 spin_lock(&sbi->lookup_lock); 273 if (!list_empty(&ino->expiring)) 274 list_del_init(&ino->expiring); 275 spin_unlock(&sbi->lookup_lock); 276 } 277 } 278 279 void autofs_kill_sb(struct super_block *); 280