text: /* SPDX-License-Identifier: GPL-2.0-or-later */
  /* Internal procfs definitions
   *
   * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   */
  
  #include <linux/proc_fs.h>
  #include <linux/proc_ns.h>
  #include <linux/refcount.h>
  #include <linux/spinlock.h>
  #include <linux/atomic.h>
  #include <linux/binfmts.h>
  #include <linux/sched/coredump.h>
  #include <linux/sched/task.h>
  
  struct ctl_table_header;
  struct mempolicy;
  
  /*
   * This is not completely implemented yet. The idea is to
   * create an in-memory tree (like the actual /proc filesystem
   * tree) of these proc_dir_entries, so that we can dynamically
   * add new files to /proc.
   *
   * parent/subdir are used for the directory structure (every /proc file has a
   * parent, but "subdir" is empty for all non-directory entries).
   * subdir_node is used to build the rb tree "subdir" of the parent.
   */
  struct proc_dir_entry {
  	/*
  	 * number of callers into module in progress;
  	 * negative -> it's going away RSN
  	 */
  	atomic_t in_use;
  	refcount_t refcnt;
  	struct list_head pde_openers;	/* who did ->open, but not ->release */
  	/* protects ->pde_openers and all struct pde_opener instances */
  	spinlock_t pde_unload_lock;
  	struct completion *pde_unload_completion;
  	const struct inode_operations *proc_iops;
  	union {
  		const struct proc_ops *proc_ops;
  		const struct file_operations *proc_dir_ops;
  	};
  	const struct dentry_operations *proc_dops;
  	union {
  		const struct seq_operations *seq_ops;
  		int (*single_show)(struct seq_file *, void *);
  	};
  	proc_write_t write;
  	void *data;
  	unsigned int state_size;
  	unsigned int low_ino;
  	nlink_t nlink;
  	kuid_t uid;
  	kgid_t gid;
  	loff_t size;
  	struct proc_dir_entry *parent;
  	struct rb_root subdir;
  	struct rb_node subdir_node;
  	char *name;
  	umode_t mode;
  	u8 flags;
  	u8 namelen;
  	char inline_name[];
  } __randomize_layout;
  
  #define SIZEOF_PDE	(				\
  	sizeof(struct proc_dir_entry) < 128 ? 128 :	\
  	sizeof(struct proc_dir_entry) < 192 ? 192 :	\
  	sizeof(struct proc_dir_entry) < 256 ? 256 :	\
  	sizeof(struct proc_dir_entry) < 512 ? 512 :	\
  	0)
  #define SIZEOF_PDE_INLINE_NAME (SIZEOF_PDE - sizeof(struct proc_dir_entry))
  
  static inline bool pde_is_permanent(const struct proc_dir_entry *pde)
  {
  	return pde->flags & PROC_ENTRY_PERMANENT;
  }
  
  extern struct kmem_cache *proc_dir_entry_cache;
  void pde_free(struct proc_dir_entry *pde);
  
  union proc_op {
  	int (*proc_get_link)(struct dentry *, struct path *);
  	int (*proc_show)(struct seq_file *m,
  		struct pid_namespace *ns, struct pid *pid,
  		struct task_struct *task);
  	const char *lsm;
  };
  
  struct proc_inode {
  	struct pid *pid;
  	unsigned int fd;
  	union proc_op op;
  	struct proc_dir_entry *pde;
  	struct ctl_table_header *sysctl;
  	struct ctl_table *sysctl_entry;
  	struct hlist_node sibling_inodes;
  	const struct proc_ns_operations *ns_ops;
  	struct inode vfs_inode;
  } __randomize_layout;
  
  /*
   * General functions
   */
  static inline struct proc_inode *PROC_I(const struct inode *inode)
  {
  	return container_of(inode, struct proc_inode, vfs_inode);
  }
  
  static inline struct proc_dir_entry *PDE(const struct inode *inode)
  {
  	return PROC_I(inode)->pde;
  }
  
  static inline void *__PDE_DATA(const struct inode *inode)
  {
  	return PDE(inode)->data;
  }
  
  static inline struct pid *proc_pid(const struct inode *inode)
  {
  	return PROC_I(inode)->pid;
  }
  
  static inline struct task_struct *get_proc_task(const struct inode *inode)
  {
  	return get_pid_task(proc_pid(inode), PIDTYPE_PID);
  }
  
  void task_dump_owner(struct task_struct *task, umode_t mode,
  		     kuid_t *ruid, kgid_t *rgid);
  
  unsigned name_to_int(const struct qstr *qstr);
  /*
   * Offset of the first process in the /proc root directory..
   */
  #define FIRST_PROCESS_ENTRY 256
  
  /* Worst case buffer size needed for holding an integer. */
  #define PROC_NUMBUF 13
  
  /*
   * array.c
   */
  extern const struct file_operations proc_tid_children_operations;
  
  extern void proc_task_name(struct seq_file *m, struct task_struct *p,
  			   bool escape);
  extern int proc_tid_stat(struct seq_file *, struct pid_namespace *,
  			 struct pid *, struct task_struct *);
  extern int proc_tgid_stat(struct seq_file *, struct pid_namespace *,
  			  struct pid *, struct task_struct *);
  extern int proc_pid_status(struct seq_file *, struct pid_namespace *,
  			   struct pid *, struct task_struct *);
  extern int proc_pid_statm(struct seq_file *, struct pid_namespace *,
  			  struct pid *, struct task_struct *);
  
  /*
   * base.c
   */
  extern const struct dentry_operations pid_dentry_operations;
  extern int pid_getattr(const struct path *, struct kstat *, u32, unsigned int);
  extern int proc_setattr(struct dentry *, struct iattr *);
  extern void proc_pid_evict_inode(struct proc_inode *);
  extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t);
  extern void pid_update_inode(struct task_struct *, struct inode *);
  extern int pid_delete_dentry(const struct dentry *);
  extern int proc_pid_readdir(struct file *, struct dir_context *);
  struct dentry *proc_pid_lookup(struct dentry *, unsigned int);
  extern loff_t mem_lseek(struct file *, loff_t, int);
  
  /* Lookups */
  typedef struct dentry *instantiate_t(struct dentry *,
  				     struct task_struct *, const void *);
  bool proc_fill_cache(struct file *, struct dir_context *, const char *, unsigned int,
  			   instantiate_t, struct task_struct *, const void *);
  
  /*
   * generic.c
   */
  struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
  		struct proc_dir_entry **parent, void *data);
  struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
  		struct proc_dir_entry *dp);
  extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int);
  struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *);
  extern int proc_readdir(struct file *, struct dir_context *);
  int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *);
  
  static inline struct proc_dir_entry *pde_get(struct proc_dir_entry *pde)
  {
  	refcount_inc(&pde->refcnt);
  	return pde;
  }
  extern void pde_put(struct proc_dir_entry *);
  
  static inline bool is_empty_pde(const struct proc_dir_entry *pde)
  {
  	return S_ISDIR(pde->mode) && !pde->proc_iops;
  }
  extern ssize_t proc_simple_write(struct file *, const char __user *, size_t, loff_t *);
  
  /*
   * inode.c
   */
  struct pde_opener {
  	struct list_head lh;
  	struct file *file;
  	bool closing;
  	struct completion *c;
  } __randomize_layout;
  extern const struct inode_operations proc_link_inode_operations;
  extern const struct inode_operations proc_pid_link_inode_operations;
  extern const struct super_operations proc_sops;
  
  void proc_init_kmemcache(void);
  void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock);
  void set_proc_pid_nlink(void);
  extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
  extern void proc_entry_rundown(struct proc_dir_entry *);
  
  /*
   * proc_namespaces.c
   */
  extern const struct inode_operations proc_ns_dir_inode_operations;
  extern const struct file_operations proc_ns_dir_operations;
  
  /*
   * proc_net.c
   */
  extern const struct file_operations proc_net_operations;
  extern const struct inode_operations proc_net_inode_operations;
  
  #ifdef CONFIG_NET
  extern int proc_net_init(void);
  #else
  static inline int proc_net_init(void) { return 0; }
  #endif
  
  /*
   * proc_self.c
   */
  extern int proc_setup_self(struct super_block *);
  
  /*
   * proc_thread_self.c
   */
  extern int proc_setup_thread_self(struct super_block *);
  extern void proc_thread_self_init(void);
  
  /*
   * proc_sysctl.c
   */
  #ifdef CONFIG_PROC_SYSCTL
  extern int proc_sys_init(void);
  extern void proc_sys_evict_inode(struct inode *inode,
  				 struct ctl_table_header *head);
  #else
  static inline void proc_sys_init(void) { }
  static inline void proc_sys_evict_inode(struct  inode *inode,
  					struct ctl_table_header *head) { }
  #endif
  
  /*
   * proc_tty.c
   */
  #ifdef CONFIG_TTY
  extern void proc_tty_init(void);
  #else
  static inline void proc_tty_init(void) {}
  #endif
  
  /*
   * root.c
   */
  extern struct proc_dir_entry proc_root;
  
  extern void proc_self_init(void);
  
  /*
   * task_[no]mmu.c
   */
  struct mem_size_stats;
  struct proc_maps_private {
  	struct inode *inode;
  	struct task_struct *task;
  	struct mm_struct *mm;
  #ifdef CONFIG_MMU
  	struct vm_area_struct *tail_vma;
  #endif
  #ifdef CONFIG_NUMA
  	struct mempolicy *task_mempolicy;
  #endif
  } __randomize_layout;
  
  struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode);
  
  extern const struct file_operations proc_pid_maps_operations;
  extern const struct file_operations proc_pid_numa_maps_operations;
  extern const struct file_operations proc_pid_smaps_operations;
  extern const struct file_operations proc_pid_smaps_rollup_operations;
  extern const struct file_operations proc_clear_refs_operations;
  extern const struct file_operations proc_pagemap_operations;
  extern const struct file_operations proc_mm_idle_operations;
  extern const struct file_operations proc_mm_swap_operations;
  
  extern unsigned long task_vsize(struct mm_struct *);
  extern unsigned long task_statm(struct mm_struct *,
  				unsigned long *, unsigned long *,
  				unsigned long *, unsigned long *);
  extern void task_mem(struct seq_file *, struct mm_struct *);
  
  extern const struct dentry_operations proc_net_dentry_ops;
  static inline void pde_force_lookup(struct proc_dir_entry *pde)
  {
  	/* /proc/net/ entries can be changed under us by setns(CLONE_NEWNET) */
  	pde->proc_dops = &proc_net_dentry_ops;
  }
  