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 #include <linux/fs_context.h> 29 #include <linux/fs_parser.h> 30 31 /* This is the range of ioctl() numbers we claim as ours */ 32 #define AUTOFS_IOC_FIRST AUTOFS_IOC_READY 33 #define AUTOFS_IOC_COUNT 32 34 35 #define AUTOFS_DEV_IOCTL_IOC_FIRST (AUTOFS_DEV_IOCTL_VERSION) 36 #define AUTOFS_DEV_IOCTL_IOC_COUNT \ 37 (AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD) 38 39 #ifdef pr_fmt 40 #undef pr_fmt 41 #endif 42 #define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__ 43 44 extern struct file_system_type autofs_fs_type; 45 46 /* 47 * Unified info structure. This is pointed to by both the dentry and 48 * inode structures. Each file in the filesystem has an instance of this 49 * structure. It holds a reference to the dentry, so dentries are never 50 * flushed while the file exists. All name lookups are dealt with at the 51 * dentry level, although the filesystem can interfere in the validation 52 * process. Readdir is implemented by traversing the dentry lists. 53 */ 54 struct autofs_info { 55 struct dentry *dentry; 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 offset; 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 static inline bool autofs_empty(struct autofs_info *ino) 152 { 153 return ino->count < 2; 154 } 155 156 struct inode *autofs_get_inode(struct super_block *, umode_t); 157 void autofs_free_ino(struct autofs_info *); 158 159 /* Expiration */ 160 int is_autofs_dentry(struct dentry *); 161 int autofs_expire_wait(const struct path *path, int rcu_walk); 162 int autofs_expire_run(struct super_block *, struct vfsmount *, 163 struct autofs_sb_info *, 164 struct autofs_packet_expire __user *); 165 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, 166 struct autofs_sb_info *sbi, unsigned int how); 167 int autofs_expire_multi(struct super_block *, struct vfsmount *, 168 struct autofs_sb_info *, int __user *); 169 170 /* Device node initialization */ 171 172 int autofs_dev_ioctl_init(void); 173 void autofs_dev_ioctl_exit(void); 174 175 /* Operations structures */ 176 177 extern const struct inode_operations autofs_symlink_inode_operations; 178 extern const struct inode_operations autofs_dir_inode_operations; 179 extern const struct file_operations autofs_dir_operations; 180 extern const struct file_operations autofs_root_operations; 181 extern const struct dentry_operations autofs_dentry_operations; 182 183 /* VFS automount flags management functions */ 184 static inline void __managed_dentry_set_managed(struct dentry *dentry) 185 { 186 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 187 } 188 189 static inline void managed_dentry_set_managed(struct dentry *dentry) 190 { 191 spin_lock(&dentry->d_lock); 192 __managed_dentry_set_managed(dentry); 193 spin_unlock(&dentry->d_lock); 194 } 195 196 static inline void __managed_dentry_clear_managed(struct dentry *dentry) 197 { 198 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 199 } 200 201 static inline void managed_dentry_clear_managed(struct dentry *dentry) 202 { 203 spin_lock(&dentry->d_lock); 204 __managed_dentry_clear_managed(dentry); 205 spin_unlock(&dentry->d_lock); 206 } 207 208 /* Initializing function */ 209 210 extern const struct fs_parameter_spec autofs_param_specs[]; 211 int autofs_init_fs_context(struct fs_context *fc); 212 struct autofs_info *autofs_new_ino(struct autofs_sb_info *); 213 void autofs_clean_ino(struct autofs_info *); 214 215 static inline int autofs_check_pipe(struct file *pipe) 216 { 217 if (!(pipe->f_mode & FMODE_CAN_WRITE)) 218 return -EINVAL; 219 if (!S_ISFIFO(file_inode(pipe)->i_mode)) 220 return -EINVAL; 221 return 0; 222 } 223 224 static inline void autofs_set_packet_pipe_flags(struct file *pipe) 225 { 226 /* We want a packet pipe */ 227 pipe->f_flags |= O_DIRECT; 228 /* We don't expect -EAGAIN */ 229 pipe->f_flags &= ~O_NONBLOCK; 230 } 231 232 static inline int autofs_prepare_pipe(struct file *pipe) 233 { 234 int ret = autofs_check_pipe(pipe); 235 if (ret < 0) 236 return ret; 237 autofs_set_packet_pipe_flags(pipe); 238 return 0; 239 } 240 241 /* Queue management functions */ 242 243 int autofs_wait(struct autofs_sb_info *, 244 const struct path *, enum autofs_notify); 245 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int); 246 void autofs_catatonic_mode(struct autofs_sb_info *); 247 248 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi) 249 { 250 return new_encode_dev(sbi->sb->s_dev); 251 } 252 253 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi) 254 { 255 return d_inode(sbi->sb->s_root)->i_ino; 256 } 257 258 static inline void __autofs_add_expiring(struct dentry *dentry) 259 { 260 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 261 struct autofs_info *ino = autofs_dentry_ino(dentry); 262 263 if (ino) { 264 if (list_empty(&ino->expiring)) 265 list_add(&ino->expiring, &sbi->expiring_list); 266 } 267 } 268 269 static 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 spin_lock(&sbi->lookup_lock); 276 if (list_empty(&ino->expiring)) 277 list_add(&ino->expiring, &sbi->expiring_list); 278 spin_unlock(&sbi->lookup_lock); 279 } 280 } 281 282 static inline void autofs_del_expiring(struct dentry *dentry) 283 { 284 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 285 struct autofs_info *ino = autofs_dentry_ino(dentry); 286 287 if (ino) { 288 spin_lock(&sbi->lookup_lock); 289 if (!list_empty(&ino->expiring)) 290 list_del_init(&ino->expiring); 291 spin_unlock(&sbi->lookup_lock); 292 } 293 } 294 295 void autofs_kill_sb(struct super_block *); 296