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 /* 46 * Unified info structure. This is pointed to by both the dentry and 47 * inode structures. Each file in the filesystem has an instance of this 48 * structure. It holds a reference to the dentry, so dentries are never 49 * flushed while the file exists. All name lookups are dealt with at the 50 * dentry level, although the filesystem can interfere in the validation 51 * process. Readdir is implemented by traversing the dentry lists. 52 */ 53 struct autofs_info { 54 struct dentry *dentry; 55 struct inode *inode; 56 57 int flags; 58 59 struct completion expire_complete; 60 61 struct list_head active; 62 int active_count; 63 64 struct list_head expiring; 65 66 struct autofs_sb_info *sbi; 67 unsigned long last_used; 68 atomic_t count; 69 70 kuid_t uid; 71 kgid_t gid; 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 struct autofs_wait_queue { 86 wait_queue_head_t queue; 87 struct autofs_wait_queue *next; 88 autofs_wqt_t wait_queue_token; 89 /* We use the following to see what we are waiting for */ 90 struct qstr name; 91 u32 dev; 92 u64 ino; 93 kuid_t uid; 94 kgid_t gid; 95 pid_t pid; 96 pid_t tgid; 97 /* This is for status reporting upon return */ 98 int status; 99 unsigned int wait_ctr; 100 }; 101 102 #define AUTOFS_SBI_MAGIC 0x6d4a556d 103 104 struct autofs_sb_info { 105 u32 magic; 106 int pipefd; 107 struct file *pipe; 108 struct pid *oz_pgrp; 109 int catatonic; 110 int version; 111 int sub_version; 112 int min_proto; 113 int max_proto; 114 unsigned long exp_timeout; 115 unsigned int type; 116 struct super_block *sb; 117 struct mutex wq_mutex; 118 struct mutex pipe_mutex; 119 spinlock_t fs_lock; 120 struct autofs_wait_queue *queues; /* Wait queue pointer */ 121 spinlock_t lookup_lock; 122 struct list_head active_list; 123 struct list_head expiring_list; 124 struct rcu_head rcu; 125 }; 126 127 static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb) 128 { 129 return sb->s_magic != AUTOFS_SUPER_MAGIC ? 130 NULL : (struct autofs_sb_info *)(sb->s_fs_info); 131 } 132 133 static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry) 134 { 135 return (struct autofs_info *)(dentry->d_fsdata); 136 } 137 138 /* autofs_oz_mode(): do we see the man behind the curtain? (The 139 * processes which do manipulations for us in user space sees the raw 140 * filesystem without "magic".) 141 */ 142 static inline int autofs_oz_mode(struct autofs_sb_info *sbi) 143 { 144 return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp; 145 } 146 147 struct inode *autofs_get_inode(struct super_block *, umode_t); 148 void autofs_free_ino(struct autofs_info *); 149 150 /* Expiration */ 151 int is_autofs_dentry(struct dentry *); 152 int autofs_expire_wait(const struct path *path, int rcu_walk); 153 int autofs_expire_run(struct super_block *, struct vfsmount *, 154 struct autofs_sb_info *, 155 struct autofs_packet_expire __user *); 156 int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, 157 struct autofs_sb_info *sbi, unsigned int how); 158 int autofs_expire_multi(struct super_block *, struct vfsmount *, 159 struct autofs_sb_info *, int __user *); 160 161 /* Device node initialization */ 162 163 int autofs_dev_ioctl_init(void); 164 void autofs_dev_ioctl_exit(void); 165 166 /* Operations structures */ 167 168 extern const struct inode_operations autofs_symlink_inode_operations; 169 extern const struct inode_operations autofs_dir_inode_operations; 170 extern const struct file_operations autofs_dir_operations; 171 extern const struct file_operations autofs_root_operations; 172 extern const struct dentry_operations autofs_dentry_operations; 173 174 /* VFS automount flags management functions */ 175 static inline void __managed_dentry_set_managed(struct dentry *dentry) 176 { 177 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 178 } 179 180 static inline void managed_dentry_set_managed(struct dentry *dentry) 181 { 182 spin_lock(&dentry->d_lock); 183 __managed_dentry_set_managed(dentry); 184 spin_unlock(&dentry->d_lock); 185 } 186 187 static inline void __managed_dentry_clear_managed(struct dentry *dentry) 188 { 189 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT); 190 } 191 192 static inline void managed_dentry_clear_managed(struct dentry *dentry) 193 { 194 spin_lock(&dentry->d_lock); 195 __managed_dentry_clear_managed(dentry); 196 spin_unlock(&dentry->d_lock); 197 } 198 199 /* Initializing function */ 200 201 int autofs_fill_super(struct super_block *, void *, int); 202 struct autofs_info *autofs_new_ino(struct autofs_sb_info *); 203 void autofs_clean_ino(struct autofs_info *); 204 205 static inline int autofs_prepare_pipe(struct file *pipe) 206 { 207 if (!(pipe->f_mode & FMODE_CAN_WRITE)) 208 return -EINVAL; 209 if (!S_ISFIFO(file_inode(pipe)->i_mode)) 210 return -EINVAL; 211 /* We want a packet pipe */ 212 pipe->f_flags |= O_DIRECT; 213 return 0; 214 } 215 216 /* Queue management functions */ 217 218 int autofs_wait(struct autofs_sb_info *, 219 const struct path *, enum autofs_notify); 220 int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int); 221 void autofs_catatonic_mode(struct autofs_sb_info *); 222 223 static inline u32 autofs_get_dev(struct autofs_sb_info *sbi) 224 { 225 return new_encode_dev(sbi->sb->s_dev); 226 } 227 228 static inline u64 autofs_get_ino(struct autofs_sb_info *sbi) 229 { 230 return d_inode(sbi->sb->s_root)->i_ino; 231 } 232 233 static inline void __autofs_add_expiring(struct dentry *dentry) 234 { 235 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 236 struct autofs_info *ino = autofs_dentry_ino(dentry); 237 238 if (ino) { 239 if (list_empty(&ino->expiring)) 240 list_add(&ino->expiring, &sbi->expiring_list); 241 } 242 } 243 244 static inline void autofs_add_expiring(struct dentry *dentry) 245 { 246 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 247 struct autofs_info *ino = autofs_dentry_ino(dentry); 248 249 if (ino) { 250 spin_lock(&sbi->lookup_lock); 251 if (list_empty(&ino->expiring)) 252 list_add(&ino->expiring, &sbi->expiring_list); 253 spin_unlock(&sbi->lookup_lock); 254 } 255 } 256 257 static inline void autofs_del_expiring(struct dentry *dentry) 258 { 259 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb); 260 struct autofs_info *ino = autofs_dentry_ino(dentry); 261 262 if (ino) { 263 spin_lock(&sbi->lookup_lock); 264 if (!list_empty(&ino->expiring)) 265 list_del_init(&ino->expiring); 266 spin_unlock(&sbi->lookup_lock); 267 } 268 } 269 270 void autofs_kill_sb(struct super_block *); 271