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