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 108 109 struct autofs_sb_info { 110 u32 magic; 111 int pipefd; 112 struct file *pipe; 113 struct pid *oz_pgrp; 114 int version; 115 int sub_version; 116 int min_proto; 117 int max_proto; 118 unsigned int flags; 119 unsigned long exp_timeout; 120 unsigned int type; 121 struct super_block *sb; 122 struct mutex wq_mutex; 123 struct mutex pipe_mutex; 124 spinlock_t fs_lock; 125 struct autofs_wait_queue *queues; /* Wait queue pointer */ 126 spinlock_t lookup_lock; 127 struct list_head active_list; 128 struct list_head expiring_list; 129 struct rcu_head rcu; 130 }; 131 132 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb) 133 { 134 return (struct autofs_sb_info *)(sb->s_fs_info); 135 } 136 137 static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry) 138 { 139 return (struct autofs_info *)(dentry->d_fsdata); 140 } 141 142 /* autofs_oz_mode(): do we see the man behind the curtain? (The 143 * processes which do manipulations for us in user space sees the raw 144 * filesystem without "magic".) 145 */ 146 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) 147 { 148 return ((sbi->flags & AUTOFS_SBI_CATATONIC) || 149 task_pgrp(current) == sbi->oz_pgrp); 150 } 151 152 struct inode *autofs_get_inode(struct super_block *, umode_t); 153 void autofs_free_ino(struct autofs_info *); 154 155 /* Expiration */ 156 int is_autofs_dentry(struct dentry *); 157 int autofs_expire_wait(const struct path *path, int rcu_walk); 158 int autofs_expire_run(struct super_block *, struct vfsmount *, 159 struct autofs_sb_info *, 160 struct autofs_packet_expire __user *); 161 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, 162 struct autofs_sb_info *sbi, unsigned int how); 163 int autofs_expire_multi(struct super_block *, struct vfsmount *, 164 struct autofs_sb_info *, int __user *); 165 166 /* Device node initialization */ 167 168 int autofs_dev_ioctl_init(void); 169 void autofs_dev_ioctl_exit(void); 170 171 /* Operations structures */ 172 173 extern const struct inode_operations autofs_symlink_inode_operations; 174 extern const struct inode_operations autofs_dir_inode_operations; 175 extern const struct file_operations autofs_dir_operations; 176 extern const struct file_operations autofs_root_operations; 177 extern const struct dentry_operations autofs_dentry_operations; 178 179 /* VFS automount flags management functions */ 180 static inline void __managed_dentry_set_managed(struct dentry *dentry) 181 { 182 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 183 } 184 185 static inline void managed_dentry_set_managed(struct dentry *dentry) 186 { 187 spin_lock(&dentry->d_lock); 188 __managed_dentry_set_managed(dentry); 189 spin_unlock(&dentry->d_lock); 190 } 191 192 static inline void __managed_dentry_clear_managed(struct dentry *dentry) 193 { 194 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 195 } 196 197 static inline void managed_dentry_clear_managed(struct dentry *dentry) 198 { 199 spin_lock(&dentry->d_lock); 200 __managed_dentry_clear_managed(dentry); 201 spin_unlock(&dentry->d_lock); 202 } 203 204 /* Initializing function */ 205 206 int autofs_fill_super(struct super_block *, void *, int); 207 struct autofs_info *autofs_new_ino(struct autofs_sb_info *); 208 void autofs_clean_ino(struct autofs_info *); 209 210 static inline int autofs_prepare_pipe(struct file *pipe) 211 { 212 if (!(pipe->f_mode & FMODE_CAN_WRITE)) 213 return -EINVAL; 214 if (!S_ISFIFO(file_inode(pipe)->i_mode)) 215 return -EINVAL; 216 /* We want a packet pipe */ 217 pipe->f_flags |= O_DIRECT; 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