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 <uapi/linux/mount.h> 20 #include <linux/mount.h> 21 #include <linux/namei.h> 22 #include <linux/uaccess.h> 23 #include <linux/mutex.h> 24 #include <linux/spinlock.h> 25 #include <linux/list.h> 26 #include <linux/completion.h> 27 #include <linux/file.h> 28 #include <linux/magic.h> 29 #include <linux/fs_context.h> 30 #include <linux/fs_parser.h> 31 #include "../mount.h" 32 #include <linux/ns_common.h> 33 34 35 /* This is the range of ioctl() numbers we claim as ours */ 36 #define AUTOFS_IOC_FIRST AUTOFS_IOC_READY 37 #define AUTOFS_IOC_COUNT 32 38 39 #define AUTOFS_DEV_IOCTL_IOC_FIRST (AUTOFS_DEV_IOCTL_VERSION) 40 #define AUTOFS_DEV_IOCTL_IOC_COUNT \ 41 (AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD) 42 43 #ifdef pr_fmt 44 #undef pr_fmt 45 #endif 46 #define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__ 47 48 extern struct file_system_type autofs_fs_type; 49 50 /* 51 * Unified info structure. This is pointed to by both the dentry and 52 * inode structures. Each file in the filesystem has an instance of this 53 * structure. It holds a reference to the dentry, so dentries are never 54 * flushed while the file exists. All name lookups are dealt with at the 55 * dentry level, although the filesystem can interfere in the validation 56 * process. Readdir is implemented by traversing the dentry lists. 57 */ 58 struct autofs_info { 59 struct dentry *dentry; 60 int flags; 61 62 struct completion expire_complete; 63 64 struct list_head active; 65 66 struct list_head expiring; 67 68 struct autofs_sb_info *sbi; 69 unsigned long exp_timeout; 70 unsigned long last_used; 71 int count; 72 73 kuid_t uid; 74 kgid_t gid; 75 struct rcu_head rcu; 76 }; 77 78 #define AUTOFS_INF_EXPIRING (1<<0) /* dentry in the process of expiring */ 79 #define AUTOFS_INF_WANT_EXPIRE (1<<1) /* the dentry is being considered 80 * for expiry, so RCU_walk is 81 * not permitted. If it progresses to 82 * actual expiry attempt, the flag is 83 * not cleared when EXPIRING is set - 84 * in that case it gets cleared only 85 * when it comes to clearing EXPIRING. 86 */ 87 #define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */ 88 89 #define AUTOFS_INF_EXPIRE_SET (1<<3) /* per-dentry expire timeout set for 90 this mount point. 91 */ 92 struct autofs_wait_queue { 93 wait_queue_head_t queue; 94 struct autofs_wait_queue *next; 95 autofs_wqt_t wait_queue_token; 96 /* We use the following to see what we are waiting for */ 97 struct qstr name; 98 u32 offset; 99 u32 dev; 100 u64 ino; 101 kuid_t uid; 102 kgid_t gid; 103 pid_t pid; 104 pid_t tgid; 105 /* This is for status reporting upon return */ 106 int status; 107 unsigned int wait_ctr; 108 }; 109 110 #define AUTOFS_SBI_MAGIC 0x6d4a556d 111 112 #define AUTOFS_SBI_CATATONIC 0x0001 113 #define AUTOFS_SBI_STRICTEXPIRE 0x0002 114 #define AUTOFS_SBI_IGNORE 0x0004 115 116 struct autofs_sb_info { 117 u32 magic; 118 int pipefd; 119 struct file *pipe; 120 struct pid *oz_pgrp; 121 u64 mnt_ns_id; 122 int version; 123 int sub_version; 124 int min_proto; 125 int max_proto; 126 unsigned int flags; 127 unsigned long exp_timeout; 128 unsigned int type; 129 struct super_block *sb; 130 struct mutex wq_mutex; 131 struct mutex pipe_mutex; 132 spinlock_t fs_lock; 133 struct autofs_wait_queue *queues; /* Wait queue pointer */ 134 spinlock_t lookup_lock; 135 struct list_head active_list; 136 struct list_head expiring_list; 137 struct rcu_head rcu; 138 }; 139 140 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb) 141 { 142 return (struct autofs_sb_info *)(sb->s_fs_info); 143 } 144 145 static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry) 146 { 147 return (struct autofs_info *)(dentry->d_fsdata); 148 } 149 150 /* autofs_oz_mode(): do we see the man behind the curtain? (The 151 * processes which do manipulations for us in user space sees the raw 152 * filesystem without "magic".) 153 */ 154 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) 155 { 156 return ((sbi->flags & AUTOFS_SBI_CATATONIC) || 157 task_pgrp(current) == sbi->oz_pgrp); 158 } 159 160 static inline bool autofs_empty(struct autofs_info *ino) 161 { 162 return ino->count < 2; 163 } 164 165 struct inode *autofs_get_inode(struct super_block *, umode_t); 166 void autofs_free_ino(struct autofs_info *); 167 168 /* Expiration */ 169 int is_autofs_dentry(struct dentry *); 170 int autofs_expire_wait(const struct path *path, int rcu_walk); 171 int autofs_expire_run(struct super_block *, struct vfsmount *, 172 struct autofs_sb_info *, 173 struct autofs_packet_expire __user *); 174 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, 175 struct autofs_sb_info *sbi, unsigned int how); 176 int autofs_expire_multi(struct super_block *, struct vfsmount *, 177 struct autofs_sb_info *, int __user *); 178 179 /* Device node initialization */ 180 181 int autofs_dev_ioctl_init(void); 182 void autofs_dev_ioctl_exit(void); 183 184 /* Operations structures */ 185 186 extern const struct inode_operations autofs_symlink_inode_operations; 187 extern const struct inode_operations autofs_dir_inode_operations; 188 extern const struct file_operations autofs_dir_operations; 189 extern const struct file_operations autofs_root_operations; 190 extern const struct dentry_operations autofs_dentry_operations; 191 192 /* VFS automount flags management functions */ 193 static inline void __managed_dentry_set_managed(struct dentry *dentry) 194 { 195 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 196 } 197 198 static inline void managed_dentry_set_managed(struct dentry *dentry) 199 { 200 spin_lock(&dentry->d_lock); 201 __managed_dentry_set_managed(dentry); 202 spin_unlock(&dentry->d_lock); 203 } 204 205 static inline void __managed_dentry_clear_managed(struct dentry *dentry) 206 { 207 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 208 } 209 210 static inline void managed_dentry_clear_managed(struct dentry *dentry) 211 { 212 spin_lock(&dentry->d_lock); 213 __managed_dentry_clear_managed(dentry); 214 spin_unlock(&dentry->d_lock); 215 } 216 217 /* Initializing function */ 218 219 extern const struct fs_parameter_spec autofs_param_specs[]; 220 int autofs_init_fs_context(struct fs_context *fc); 221 struct autofs_info *autofs_new_ino(struct autofs_sb_info *); 222 void autofs_clean_ino(struct autofs_info *); 223 224 static inline int autofs_check_pipe(struct file *pipe) 225 { 226 if (pipe->f_mode & FMODE_PATH) 227 return -EINVAL; 228 if (!(pipe->f_mode & FMODE_CAN_WRITE)) 229 return -EINVAL; 230 if (!S_ISFIFO(file_inode(pipe)->i_mode)) 231 return -EINVAL; 232 return 0; 233 } 234 235 static inline void autofs_set_packet_pipe_flags(struct file *pipe) 236 { 237 /* We want a packet pipe */ 238 pipe->f_flags |= O_DIRECT; 239 /* We don't expect -EAGAIN */ 240 pipe->f_flags &= ~O_NONBLOCK; 241 } 242 243 static inline int autofs_prepare_pipe(struct file *pipe) 244 { 245 int ret = autofs_check_pipe(pipe); 246 if (ret < 0) 247 return ret; 248 autofs_set_packet_pipe_flags(pipe); 249 return 0; 250 } 251 252 /* Queue management functions */ 253 254 int autofs_wait(struct autofs_sb_info *, 255 const struct path *, enum autofs_notify); 256 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int); 257 void autofs_catatonic_mode(struct autofs_sb_info *); 258 259 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi) 260 { 261 return new_encode_dev(sbi->sb->s_dev); 262 } 263 264 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi) 265 { 266 return d_inode(sbi->sb->s_root)->i_ino; 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 if (list_empty(&ino->expiring)) 276 list_add(&ino->expiring, &sbi->expiring_list); 277 } 278 } 279 280 static inline void autofs_add_expiring(struct dentry *dentry) 281 { 282 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 283 struct autofs_info *ino = autofs_dentry_ino(dentry); 284 285 if (ino) { 286 spin_lock(&sbi->lookup_lock); 287 if (list_empty(&ino->expiring)) 288 list_add(&ino->expiring, &sbi->expiring_list); 289 spin_unlock(&sbi->lookup_lock); 290 } 291 } 292 293 static inline void autofs_del_expiring(struct dentry *dentry) 294 { 295 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 296 struct autofs_info *ino = autofs_dentry_ino(dentry); 297 298 if (ino) { 299 spin_lock(&sbi->lookup_lock); 300 if (!list_empty(&ino->expiring)) 301 list_del_init(&ino->expiring); 302 spin_unlock(&sbi->lookup_lock); 303 } 304 } 305 306 void autofs_kill_sb(struct super_block *); 307