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 exp_timeout; 66 unsigned long last_used; 67 int 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 #define AUTOFS_INF_EXPIRE_SET (1<<3) /* per-dentry expire timeout set for 86 this mount point. 87 */ 88 struct autofs_wait_queue { 89 wait_queue_head_t queue; 90 struct autofs_wait_queue *next; 91 autofs_wqt_t wait_queue_token; 92 /* We use the following to see what we are waiting for */ 93 struct qstr name; 94 u32 offset; 95 u32 dev; 96 u64 ino; 97 kuid_t uid; 98 kgid_t gid; 99 pid_t pid; 100 pid_t tgid; 101 /* This is for status reporting upon return */ 102 int status; 103 unsigned int wait_ctr; 104 }; 105 106 #define AUTOFS_SBI_MAGIC 0x6d4a556d 107 108 #define AUTOFS_SBI_CATATONIC 0x0001 109 #define AUTOFS_SBI_STRICTEXPIRE 0x0002 110 #define AUTOFS_SBI_IGNORE 0x0004 111 112 struct autofs_sb_info { 113 u32 magic; 114 int pipefd; 115 struct file *pipe; 116 struct pid *oz_pgrp; 117 int version; 118 int sub_version; 119 int min_proto; 120 int max_proto; 121 unsigned int flags; 122 unsigned long exp_timeout; 123 unsigned int type; 124 struct super_block *sb; 125 struct mutex wq_mutex; 126 struct mutex pipe_mutex; 127 spinlock_t fs_lock; 128 struct autofs_wait_queue *queues; /* Wait queue pointer */ 129 spinlock_t lookup_lock; 130 struct list_head active_list; 131 struct list_head expiring_list; 132 struct rcu_head rcu; 133 }; 134 135 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb) 136 { 137 return (struct autofs_sb_info *)(sb->s_fs_info); 138 } 139 140 static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry) 141 { 142 return (struct autofs_info *)(dentry->d_fsdata); 143 } 144 145 /* autofs_oz_mode(): do we see the man behind the curtain? (The 146 * processes which do manipulations for us in user space sees the raw 147 * filesystem without "magic".) 148 */ 149 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) 150 { 151 return ((sbi->flags & AUTOFS_SBI_CATATONIC) || 152 task_pgrp(current) == sbi->oz_pgrp); 153 } 154 155 static inline bool autofs_empty(struct autofs_info *ino) 156 { 157 return ino->count < 2; 158 } 159 160 struct inode *autofs_get_inode(struct super_block *, umode_t); 161 void autofs_free_ino(struct autofs_info *); 162 163 /* Expiration */ 164 int is_autofs_dentry(struct dentry *); 165 int autofs_expire_wait(const struct path *path, int rcu_walk); 166 int autofs_expire_run(struct super_block *, struct vfsmount *, 167 struct autofs_sb_info *, 168 struct autofs_packet_expire __user *); 169 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, 170 struct autofs_sb_info *sbi, unsigned int how); 171 int autofs_expire_multi(struct super_block *, struct vfsmount *, 172 struct autofs_sb_info *, int __user *); 173 174 /* Device node initialization */ 175 176 int autofs_dev_ioctl_init(void); 177 void autofs_dev_ioctl_exit(void); 178 179 /* Operations structures */ 180 181 extern const struct inode_operations autofs_symlink_inode_operations; 182 extern const struct inode_operations autofs_dir_inode_operations; 183 extern const struct file_operations autofs_dir_operations; 184 extern const struct file_operations autofs_root_operations; 185 extern const struct dentry_operations autofs_dentry_operations; 186 187 /* VFS automount flags management functions */ 188 static inline void __managed_dentry_set_managed(struct dentry *dentry) 189 { 190 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 191 } 192 193 static inline void managed_dentry_set_managed(struct dentry *dentry) 194 { 195 spin_lock(&dentry->d_lock); 196 __managed_dentry_set_managed(dentry); 197 spin_unlock(&dentry->d_lock); 198 } 199 200 static inline void __managed_dentry_clear_managed(struct dentry *dentry) 201 { 202 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 203 } 204 205 static inline void managed_dentry_clear_managed(struct dentry *dentry) 206 { 207 spin_lock(&dentry->d_lock); 208 __managed_dentry_clear_managed(dentry); 209 spin_unlock(&dentry->d_lock); 210 } 211 212 /* Initializing function */ 213 214 extern const struct fs_parameter_spec autofs_param_specs[]; 215 int autofs_init_fs_context(struct fs_context *fc); 216 struct autofs_info *autofs_new_ino(struct autofs_sb_info *); 217 void autofs_clean_ino(struct autofs_info *); 218 219 static inline int autofs_check_pipe(struct file *pipe) 220 { 221 if (!(pipe->f_mode & FMODE_CAN_WRITE)) 222 return -EINVAL; 223 if (!S_ISFIFO(file_inode(pipe)->i_mode)) 224 return -EINVAL; 225 return 0; 226 } 227 228 static inline void autofs_set_packet_pipe_flags(struct file *pipe) 229 { 230 /* We want a packet pipe */ 231 pipe->f_flags |= O_DIRECT; 232 /* We don't expect -EAGAIN */ 233 pipe->f_flags &= ~O_NONBLOCK; 234 } 235 236 static inline int autofs_prepare_pipe(struct file *pipe) 237 { 238 int ret = autofs_check_pipe(pipe); 239 if (ret < 0) 240 return ret; 241 autofs_set_packet_pipe_flags(pipe); 242 return 0; 243 } 244 245 /* Queue management functions */ 246 247 int autofs_wait(struct autofs_sb_info *, 248 const struct path *, enum autofs_notify); 249 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int); 250 void autofs_catatonic_mode(struct autofs_sb_info *); 251 252 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi) 253 { 254 return new_encode_dev(sbi->sb->s_dev); 255 } 256 257 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi) 258 { 259 return d_inode(sbi->sb->s_root)->i_ino; 260 } 261 262 static inline void __autofs_add_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 if (list_empty(&ino->expiring)) 269 list_add(&ino->expiring, &sbi->expiring_list); 270 } 271 } 272 273 static inline void autofs_add_expiring(struct dentry *dentry) 274 { 275 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 276 struct autofs_info *ino = autofs_dentry_ino(dentry); 277 278 if (ino) { 279 spin_lock(&sbi->lookup_lock); 280 if (list_empty(&ino->expiring)) 281 list_add(&ino->expiring, &sbi->expiring_list); 282 spin_unlock(&sbi->lookup_lock); 283 } 284 } 285 286 static inline void autofs_del_expiring(struct dentry *dentry) 287 { 288 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 289 struct autofs_info *ino = autofs_dentry_ino(dentry); 290 291 if (ino) { 292 spin_lock(&sbi->lookup_lock); 293 if (!list_empty(&ino->expiring)) 294 list_del_init(&ino->expiring); 295 spin_unlock(&sbi->lookup_lock); 296 } 297 } 298 299 void autofs_kill_sb(struct super_block *); 300