/* SPDX-License-Identifier: GPL-2.0-or-later */

  /*
   *  Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
   *  Copyright 2005-2006 Ian Kent <raven@themaw.net>

   */
  
  /* Internal header file for autofs */
  
  #include <linux/auto_fs.h>
  #include <linux/auto_dev-ioctl.h>
  
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/time.h>
  #include <linux/string.h>
  #include <linux/wait.h>
  #include <linux/sched.h>

  #include <linux/sched/signal.h>

  #include <linux/mount.h>
  #include <linux/namei.h>
  #include <linux/uaccess.h>
  #include <linux/mutex.h>
  #include <linux/spinlock.h>
  #include <linux/list.h>
  #include <linux/completion.h>

  #include <linux/file.h>

  #include <linux/magic.h>

  
  /* This is the range of ioctl() numbers we claim as ours */
  #define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
  #define AUTOFS_IOC_COUNT     32
  
  #define AUTOFS_DEV_IOCTL_IOC_FIRST	(AUTOFS_DEV_IOCTL_VERSION)
  #define AUTOFS_DEV_IOCTL_IOC_COUNT \
  	(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD)
  
  #ifdef pr_fmt
  #undef pr_fmt
  #endif
  #define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__

  extern struct file_system_type autofs_fs_type;

  /*
   * Unified info structure.  This is pointed to by both the dentry and
   * inode structures.  Each file in the filesystem has an instance of this
   * structure.  It holds a reference to the dentry, so dentries are never
   * flushed while the file exists.  All name lookups are dealt with at the
   * dentry level, although the filesystem can interfere in the validation
   * process.  Readdir is implemented by traversing the dentry lists.
   */
  struct autofs_info {
  	struct dentry	*dentry;
  	struct inode	*inode;
  
  	int		flags;
  
  	struct completion expire_complete;
  
  	struct list_head active;

  
  	struct list_head expiring;
  
  	struct autofs_sb_info *sbi;
  	unsigned long last_used;

  	int count;

  
  	kuid_t uid;
  	kgid_t gid;

  	struct rcu_head rcu;

  };
  
  #define AUTOFS_INF_EXPIRING	(1<<0) /* dentry in the process of expiring */
  #define AUTOFS_INF_WANT_EXPIRE	(1<<1) /* the dentry is being considered
  					* for expiry, so RCU_walk is
  					* not permitted.  If it progresses to
  					* actual expiry attempt, the flag is
  					* not cleared when EXPIRING is set -
  					* in that case it gets cleared only
  					* when it comes to clearing EXPIRING.
  					*/
  #define AUTOFS_INF_PENDING	(1<<2) /* dentry pending mount */
  
  struct autofs_wait_queue {
  	wait_queue_head_t queue;
  	struct autofs_wait_queue *next;
  	autofs_wqt_t wait_queue_token;
  	/* We use the following to see what we are waiting for */
  	struct qstr name;
  	u32 dev;
  	u64 ino;
  	kuid_t uid;
  	kgid_t gid;
  	pid_t pid;
  	pid_t tgid;
  	/* This is for status reporting upon return */
  	int status;
  	unsigned int wait_ctr;
  };
  
  #define AUTOFS_SBI_MAGIC 0x6d4a556d

  #define AUTOFS_SBI_CATATONIC	0x0001

  #define AUTOFS_SBI_STRICTEXPIRE 0x0002

  #define AUTOFS_SBI_IGNORE	0x0004

  struct autofs_sb_info {
  	u32 magic;
  	int pipefd;
  	struct file *pipe;
  	struct pid *oz_pgrp;

  	int version;
  	int sub_version;
  	int min_proto;
  	int max_proto;

  	unsigned int flags;

  	unsigned long exp_timeout;
  	unsigned int type;
  	struct super_block *sb;
  	struct mutex wq_mutex;
  	struct mutex pipe_mutex;
  	spinlock_t fs_lock;
  	struct autofs_wait_queue *queues; /* Wait queue pointer */
  	spinlock_t lookup_lock;
  	struct list_head active_list;
  	struct list_head expiring_list;
  	struct rcu_head rcu;
  };
  
  static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
  {

  	return (struct autofs_sb_info *)(sb->s_fs_info);

  }
  
  static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry)
  {
  	return (struct autofs_info *)(dentry->d_fsdata);
  }
  
  /* autofs_oz_mode(): do we see the man behind the curtain?  (The
   * processes which do manipulations for us in user space sees the raw
   * filesystem without "magic".)
   */
  static inline int autofs_oz_mode(struct autofs_sb_info *sbi)
  {

  	return ((sbi->flags & AUTOFS_SBI_CATATONIC) ||
  		 task_pgrp(current) == sbi->oz_pgrp);

  }
  
  struct inode *autofs_get_inode(struct super_block *, umode_t);
  void autofs_free_ino(struct autofs_info *);
  
  /* Expiration */
  int is_autofs_dentry(struct dentry *);
  int autofs_expire_wait(const struct path *path, int rcu_walk);
  int autofs_expire_run(struct super_block *, struct vfsmount *,
  		      struct autofs_sb_info *,
  		      struct autofs_packet_expire __user *);
  int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,

  			   struct autofs_sb_info *sbi, unsigned int how);

  int autofs_expire_multi(struct super_block *, struct vfsmount *,
  			struct autofs_sb_info *, int __user *);

  
  /* Device node initialization */
  
  int autofs_dev_ioctl_init(void);
  void autofs_dev_ioctl_exit(void);
  
  /* Operations structures */
  
  extern const struct inode_operations autofs_symlink_inode_operations;
  extern const struct inode_operations autofs_dir_inode_operations;
  extern const struct file_operations autofs_dir_operations;
  extern const struct file_operations autofs_root_operations;
  extern const struct dentry_operations autofs_dentry_operations;
  
  /* VFS automount flags management functions */
  static inline void __managed_dentry_set_managed(struct dentry *dentry)
  {
  	dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
  }
  
  static inline void managed_dentry_set_managed(struct dentry *dentry)
  {
  	spin_lock(&dentry->d_lock);
  	__managed_dentry_set_managed(dentry);
  	spin_unlock(&dentry->d_lock);
  }
  
  static inline void __managed_dentry_clear_managed(struct dentry *dentry)
  {
  	dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
  }
  
  static inline void managed_dentry_clear_managed(struct dentry *dentry)
  {
  	spin_lock(&dentry->d_lock);
  	__managed_dentry_clear_managed(dentry);
  	spin_unlock(&dentry->d_lock);
  }
  
  /* Initializing function */
  
  int autofs_fill_super(struct super_block *, void *, int);
  struct autofs_info *autofs_new_ino(struct autofs_sb_info *);
  void autofs_clean_ino(struct autofs_info *);
  
  static inline int autofs_prepare_pipe(struct file *pipe)
  {
  	if (!(pipe->f_mode & FMODE_CAN_WRITE))
  		return -EINVAL;
  	if (!S_ISFIFO(file_inode(pipe)->i_mode))
  		return -EINVAL;
  	/* We want a packet pipe */
  	pipe->f_flags |= O_DIRECT;

  	/* We don't expect -EAGAIN */
  	pipe->f_flags &= ~O_NONBLOCK;

  	return 0;
  }
  
  /* Queue management functions */
  
  int autofs_wait(struct autofs_sb_info *,
  		 const struct path *, enum autofs_notify);
  int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
  void autofs_catatonic_mode(struct autofs_sb_info *);
  
  static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)
  {
  	return new_encode_dev(sbi->sb->s_dev);
  }
  
  static inline u64 autofs_get_ino(struct autofs_sb_info *sbi)
  {
  	return d_inode(sbi->sb->s_root)->i_ino;
  }
  
  static inline void __autofs_add_expiring(struct dentry *dentry)
  {
  	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
  	struct autofs_info *ino = autofs_dentry_ino(dentry);
  
  	if (ino) {
  		if (list_empty(&ino->expiring))
  			list_add(&ino->expiring, &sbi->expiring_list);
  	}
  }
  
  static inline void autofs_add_expiring(struct dentry *dentry)
  {
  	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
  	struct autofs_info *ino = autofs_dentry_ino(dentry);
  
  	if (ino) {
  		spin_lock(&sbi->lookup_lock);
  		if (list_empty(&ino->expiring))
  			list_add(&ino->expiring, &sbi->expiring_list);
  		spin_unlock(&sbi->lookup_lock);
  	}
  }
  
  static inline void autofs_del_expiring(struct dentry *dentry)
  {
  	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
  	struct autofs_info *ino = autofs_dentry_ino(dentry);
  
  	if (ino) {
  		spin_lock(&sbi->lookup_lock);
  		if (!list_empty(&ino->expiring))
  			list_del_init(&ino->expiring);
  		spin_unlock(&sbi->lookup_lock);
  	}
  }
  
  void autofs_kill_sb(struct super_block *);