1 /* 2 * Copyright 1997-1998 Transmeta Corporation - All Rights Reserved 3 * Copyright 2005-2006 Ian Kent <raven@themaw.net> 4 * 5 * This file is part of the Linux kernel and is made available under 6 * the terms of the GNU General Public License, version 2, or at your 7 * option, any later version, incorporated herein by reference. 8 */ 9 10 /* Internal header file for autofs */ 11 12 #include <linux/auto_fs.h> 13 #include <linux/auto_dev-ioctl.h> 14 15 #include <linux/kernel.h> 16 #include <linux/slab.h> 17 #include <linux/time.h> 18 #include <linux/string.h> 19 #include <linux/wait.h> 20 #include <linux/sched.h> 21 #include <linux/sched/signal.h> 22 #include <linux/mount.h> 23 #include <linux/namei.h> 24 #include <linux/uaccess.h> 25 #include <linux/mutex.h> 26 #include <linux/spinlock.h> 27 #include <linux/list.h> 28 #include <linux/completion.h> 29 #include <linux/file.h> 30 #include <linux/magic.h> 31 32 /* This is the range of ioctl() numbers we claim as ours */ 33 #define AUTOFS_IOC_FIRST AUTOFS_IOC_READY 34 #define AUTOFS_IOC_COUNT 32 35 36 #define AUTOFS_DEV_IOCTL_IOC_FIRST (AUTOFS_DEV_IOCTL_VERSION) 37 #define AUTOFS_DEV_IOCTL_IOC_COUNT \ 38 (AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD) 39 40 #ifdef pr_fmt 41 #undef pr_fmt 42 #endif 43 #define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__ 44 45 extern struct file_system_type autofs_fs_type; 46 47 /* 48 * Unified info structure. This is pointed to by both the dentry and 49 * inode structures. Each file in the filesystem has an instance of this 50 * structure. It holds a reference to the dentry, so dentries are never 51 * flushed while the file exists. All name lookups are dealt with at the 52 * dentry level, although the filesystem can interfere in the validation 53 * process. Readdir is implemented by traversing the dentry lists. 54 */ 55 struct autofs_info { 56 struct dentry *dentry; 57 struct inode *inode; 58 59 int flags; 60 61 struct completion expire_complete; 62 63 struct list_head active; 64 int active_count; 65 66 struct list_head expiring; 67 68 struct autofs_sb_info *sbi; 69 unsigned long last_used; 70 atomic_t count; 71 72 kuid_t uid; 73 kgid_t gid; 74 }; 75 76 #define AUTOFS_INF_EXPIRING (1<<0) /* dentry in the process of expiring */ 77 #define AUTOFS_INF_WANT_EXPIRE (1<<1) /* the dentry is being considered 78 * for expiry, so RCU_walk is 79 * not permitted. If it progresses to 80 * actual expiry attempt, the flag is 81 * not cleared when EXPIRING is set - 82 * in that case it gets cleared only 83 * when it comes to clearing EXPIRING. 84 */ 85 #define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */ 86 87 struct autofs_wait_queue { 88 wait_queue_head_t queue; 89 struct autofs_wait_queue *next; 90 autofs_wqt_t wait_queue_token; 91 /* We use the following to see what we are waiting for */ 92 struct qstr name; 93 u32 dev; 94 u64 ino; 95 kuid_t uid; 96 kgid_t gid; 97 pid_t pid; 98 pid_t tgid; 99 /* This is for status reporting upon return */ 100 int status; 101 unsigned int wait_ctr; 102 }; 103 104 #define AUTOFS_SBI_MAGIC 0x6d4a556d 105 106 #define AUTOFS_SBI_CATATONIC 0x0001 107 #define AUTOFS_SBI_STRICTEXPIRE 0x0002 108 #define AUTOFS_SBI_IGNORE 0x0004 109 110 struct autofs_sb_info { 111 u32 magic; 112 int pipefd; 113 struct file *pipe; 114 struct pid *oz_pgrp; 115 int version; 116 int sub_version; 117 int min_proto; 118 int max_proto; 119 unsigned int flags; 120 unsigned long exp_timeout; 121 unsigned int type; 122 struct super_block *sb; 123 struct mutex wq_mutex; 124 struct mutex pipe_mutex; 125 spinlock_t fs_lock; 126 struct autofs_wait_queue *queues; /* Wait queue pointer */ 127 spinlock_t lookup_lock; 128 struct list_head active_list; 129 struct list_head expiring_list; 130 struct rcu_head rcu; 131 }; 132 133 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb) 134 { 135 return (struct autofs_sb_info *)(sb->s_fs_info); 136 } 137 138 static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry) 139 { 140 return (struct autofs_info *)(dentry->d_fsdata); 141 } 142 143 /* autofs_oz_mode(): do we see the man behind the curtain? (The 144 * processes which do manipulations for us in user space sees the raw 145 * filesystem without "magic".) 146 */ 147 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) 148 { 149 return ((sbi->flags & AUTOFS_SBI_CATATONIC) || 150 task_pgrp(current) == sbi->oz_pgrp); 151 } 152 153 struct inode *autofs_get_inode(struct super_block *, umode_t); 154 void autofs_free_ino(struct autofs_info *); 155 156 /* Expiration */ 157 int is_autofs_dentry(struct dentry *); 158 int autofs_expire_wait(const struct path *path, int rcu_walk); 159 int autofs_expire_run(struct super_block *, struct vfsmount *, 160 struct autofs_sb_info *, 161 struct autofs_packet_expire __user *); 162 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, 163 struct autofs_sb_info *sbi, unsigned int how); 164 int autofs_expire_multi(struct super_block *, struct vfsmount *, 165 struct autofs_sb_info *, int __user *); 166 167 /* Device node initialization */ 168 169 int autofs_dev_ioctl_init(void); 170 void autofs_dev_ioctl_exit(void); 171 172 /* Operations structures */ 173 174 extern const struct inode_operations autofs_symlink_inode_operations; 175 extern const struct inode_operations autofs_dir_inode_operations; 176 extern const struct file_operations autofs_dir_operations; 177 extern const struct file_operations autofs_root_operations; 178 extern const struct dentry_operations autofs_dentry_operations; 179 180 /* VFS automount flags management functions */ 181 static inline void __managed_dentry_set_managed(struct dentry *dentry) 182 { 183 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 184 } 185 186 static inline void managed_dentry_set_managed(struct dentry *dentry) 187 { 188 spin_lock(&dentry->d_lock); 189 __managed_dentry_set_managed(dentry); 190 spin_unlock(&dentry->d_lock); 191 } 192 193 static inline void __managed_dentry_clear_managed(struct dentry *dentry) 194 { 195 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 196 } 197 198 static inline void managed_dentry_clear_managed(struct dentry *dentry) 199 { 200 spin_lock(&dentry->d_lock); 201 __managed_dentry_clear_managed(dentry); 202 spin_unlock(&dentry->d_lock); 203 } 204 205 /* Initializing function */ 206 207 int autofs_fill_super(struct super_block *, void *, int); 208 struct autofs_info *autofs_new_ino(struct autofs_sb_info *); 209 void autofs_clean_ino(struct autofs_info *); 210 211 static inline int autofs_prepare_pipe(struct file *pipe) 212 { 213 if (!(pipe->f_mode & FMODE_CAN_WRITE)) 214 return -EINVAL; 215 if (!S_ISFIFO(file_inode(pipe)->i_mode)) 216 return -EINVAL; 217 /* We want a packet pipe */ 218 pipe->f_flags |= O_DIRECT; 219 /* We don't expect -EAGAIN */ 220 pipe->f_flags &= ~O_NONBLOCK; 221 return 0; 222 } 223 224 /* Queue management functions */ 225 226 int autofs_wait(struct autofs_sb_info *, 227 const struct path *, enum autofs_notify); 228 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int); 229 void autofs_catatonic_mode(struct autofs_sb_info *); 230 231 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi) 232 { 233 return new_encode_dev(sbi->sb->s_dev); 234 } 235 236 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi) 237 { 238 return d_inode(sbi->sb->s_root)->i_ino; 239 } 240 241 static inline void __autofs_add_expiring(struct dentry *dentry) 242 { 243 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 244 struct autofs_info *ino = autofs_dentry_ino(dentry); 245 246 if (ino) { 247 if (list_empty(&ino->expiring)) 248 list_add(&ino->expiring, &sbi->expiring_list); 249 } 250 } 251 252 static inline void autofs_add_expiring(struct dentry *dentry) 253 { 254 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 255 struct autofs_info *ino = autofs_dentry_ino(dentry); 256 257 if (ino) { 258 spin_lock(&sbi->lookup_lock); 259 if (list_empty(&ino->expiring)) 260 list_add(&ino->expiring, &sbi->expiring_list); 261 spin_unlock(&sbi->lookup_lock); 262 } 263 } 264 265 static inline void autofs_del_expiring(struct dentry *dentry) 266 { 267 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 268 struct autofs_info *ino = autofs_dentry_ino(dentry); 269 270 if (ino) { 271 spin_lock(&sbi->lookup_lock); 272 if (!list_empty(&ino->expiring)) 273 list_del_init(&ino->expiring); 274 spin_unlock(&sbi->lookup_lock); 275 } 276 } 277 278 void autofs_kill_sb(struct super_block *); 279