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1/* SPDX-License-Identifier: GPL-2.0-or-later */2/*3 * Copyright 1997-1998 Transmeta Corporation - All Rights Reserved4 * 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#include <linux/fs_context.h>29#include <linux/fs_parser.h>30 31/* This is the range of ioctl() numbers we claim as ours */32#define AUTOFS_IOC_FIRST AUTOFS_IOC_READY33#define AUTOFS_IOC_COUNT 3234 35#define AUTOFS_DEV_IOCTL_IOC_FIRST (AUTOFS_DEV_IOCTL_VERSION)36#define AUTOFS_DEV_IOCTL_IOC_COUNT \37 (AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD)38 39#ifdef pr_fmt40#undef pr_fmt41#endif42#define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__43 44extern struct file_system_type autofs_fs_type;45 46/*47 * Unified info structure. This is pointed to by both the dentry and48 * inode structures. Each file in the filesystem has an instance of this49 * structure. It holds a reference to the dentry, so dentries are never50 * flushed while the file exists. All name lookups are dealt with at the51 * dentry level, although the filesystem can interfere in the validation52 * process. Readdir is implemented by traversing the dentry lists.53 */54struct autofs_info {55 struct dentry *dentry;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 exp_timeout;66 unsigned long last_used;67 int count;68 69 kuid_t uid;70 kgid_t gid;71 struct rcu_head rcu;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 considered76 * for expiry, so RCU_walk is77 * not permitted. If it progresses to78 * actual expiry attempt, the flag is79 * not cleared when EXPIRING is set -80 * in that case it gets cleared only81 * when it comes to clearing EXPIRING.82 */83#define AUTOFS_INF_PENDING (1<<2) /* dentry pending mount */84 85#define AUTOFS_INF_EXPIRE_SET (1<<3) /* per-dentry expire timeout set for86 this mount point.87 */88struct autofs_wait_queue {89 wait_queue_head_t queue;90 struct autofs_wait_queue *next;91 autofs_wqt_t wait_queue_token;92 /* We use the following to see what we are waiting for */93 struct qstr name;94 u32 offset;95 u32 dev;96 u64 ino;97 kuid_t uid;98 kgid_t gid;99 pid_t pid;100 pid_t tgid;101 /* This is for status reporting upon return */102 int status;103 unsigned int wait_ctr;104};105 106#define AUTOFS_SBI_MAGIC 0x6d4a556d107 108#define AUTOFS_SBI_CATATONIC 0x0001109#define AUTOFS_SBI_STRICTEXPIRE 0x0002110#define AUTOFS_SBI_IGNORE 0x0004111 112struct autofs_sb_info {113 u32 magic;114 int pipefd;115 struct file *pipe;116 struct pid *oz_pgrp;117 int version;118 int sub_version;119 int min_proto;120 int max_proto;121 unsigned int flags;122 unsigned long exp_timeout;123 unsigned int type;124 struct super_block *sb;125 struct mutex wq_mutex;126 struct mutex pipe_mutex;127 spinlock_t fs_lock;128 struct autofs_wait_queue *queues; /* Wait queue pointer */129 spinlock_t lookup_lock;130 struct list_head active_list;131 struct list_head expiring_list;132 struct rcu_head rcu;133};134 135static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)136{137 return (struct autofs_sb_info *)(sb->s_fs_info);138}139 140static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry)141{142 return (struct autofs_info *)(dentry->d_fsdata);143}144 145/* autofs_oz_mode(): do we see the man behind the curtain? (The146 * processes which do manipulations for us in user space sees the raw147 * filesystem without "magic".)148 */149static inline int autofs_oz_mode(struct autofs_sb_info *sbi)150{151 return ((sbi->flags & AUTOFS_SBI_CATATONIC) ||152 task_pgrp(current) == sbi->oz_pgrp);153}154 155static inline bool autofs_empty(struct autofs_info *ino)156{157 return ino->count < 2;158}159 160struct inode *autofs_get_inode(struct super_block *, umode_t);161void autofs_free_ino(struct autofs_info *);162 163/* Expiration */164int is_autofs_dentry(struct dentry *);165int autofs_expire_wait(const struct path *path, int rcu_walk);166int autofs_expire_run(struct super_block *, struct vfsmount *,167 struct autofs_sb_info *,168 struct autofs_packet_expire __user *);169int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,170 struct autofs_sb_info *sbi, unsigned int how);171int autofs_expire_multi(struct super_block *, struct vfsmount *,172 struct autofs_sb_info *, int __user *);173 174/* Device node initialization */175 176int autofs_dev_ioctl_init(void);177void autofs_dev_ioctl_exit(void);178 179/* Operations structures */180 181extern const struct inode_operations autofs_symlink_inode_operations;182extern const struct inode_operations autofs_dir_inode_operations;183extern const struct file_operations autofs_dir_operations;184extern const struct file_operations autofs_root_operations;185extern const struct dentry_operations autofs_dentry_operations;186 187/* VFS automount flags management functions */188static inline void __managed_dentry_set_managed(struct dentry *dentry)189{190 dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);191}192 193static inline void managed_dentry_set_managed(struct dentry *dentry)194{195 spin_lock(&dentry->d_lock);196 __managed_dentry_set_managed(dentry);197 spin_unlock(&dentry->d_lock);198}199 200static inline void __managed_dentry_clear_managed(struct dentry *dentry)201{202 dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);203}204 205static inline void managed_dentry_clear_managed(struct dentry *dentry)206{207 spin_lock(&dentry->d_lock);208 __managed_dentry_clear_managed(dentry);209 spin_unlock(&dentry->d_lock);210}211 212/* Initializing function */213 214extern const struct fs_parameter_spec autofs_param_specs[];215int autofs_init_fs_context(struct fs_context *fc);216struct autofs_info *autofs_new_ino(struct autofs_sb_info *);217void autofs_clean_ino(struct autofs_info *);218 219static inline int autofs_check_pipe(struct file *pipe)220{221 if (!(pipe->f_mode & FMODE_CAN_WRITE))222 return -EINVAL;223 if (!S_ISFIFO(file_inode(pipe)->i_mode))224 return -EINVAL;225 return 0;226}227 228static inline void autofs_set_packet_pipe_flags(struct file *pipe)229{230 /* We want a packet pipe */231 pipe->f_flags |= O_DIRECT;232 /* We don't expect -EAGAIN */233 pipe->f_flags &= ~O_NONBLOCK;234}235 236static inline int autofs_prepare_pipe(struct file *pipe)237{238 int ret = autofs_check_pipe(pipe);239 if (ret < 0)240 return ret;241 autofs_set_packet_pipe_flags(pipe);242 return 0;243}244 245/* Queue management functions */246 247int autofs_wait(struct autofs_sb_info *,248 const struct path *, enum autofs_notify);249int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);250void autofs_catatonic_mode(struct autofs_sb_info *);251 252static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)253{254 return new_encode_dev(sbi->sb->s_dev);255}256 257static inline u64 autofs_get_ino(struct autofs_sb_info *sbi)258{259 return d_inode(sbi->sb->s_root)->i_ino;260}261 262static inline void __autofs_add_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 if (list_empty(&ino->expiring))269 list_add(&ino->expiring, &sbi->expiring_list);270 }271}272 273static inline void autofs_add_expiring(struct dentry *dentry)274{275 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);276 struct autofs_info *ino = autofs_dentry_ino(dentry);277 278 if (ino) {279 spin_lock(&sbi->lookup_lock);280 if (list_empty(&ino->expiring))281 list_add(&ino->expiring, &sbi->expiring_list);282 spin_unlock(&sbi->lookup_lock);283 }284}285 286static inline void autofs_del_expiring(struct dentry *dentry)287{288 struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);289 struct autofs_info *ino = autofs_dentry_ino(dentry);290 291 if (ino) {292 spin_lock(&sbi->lookup_lock);293 if (!list_empty(&ino->expiring))294 list_del_init(&ino->expiring);295 spin_unlock(&sbi->lookup_lock);296 }297}298 299void autofs_kill_sb(struct super_block *);300