fs/proc/internal.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /* Internal procfs definitions
   3  *
   4  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #include <linux/proc_fs.h>
   9 #include <linux/proc_ns.h>
  10 #include <linux/refcount.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/atomic.h>
  13 #include <linux/binfmts.h>
  14 #include <linux/sched/coredump.h>
  15 #include <linux/sched/task.h>
  16 #include <linux/mm.h>
  17
  18 struct ctl_table_header;
  19 struct mempolicy;
  20
  21 /*
  22  * This is not completely implemented yet. The idea is to
  23  * create an in-memory tree (like the actual /proc filesystem
  24  * tree) of these proc_dir_entries, so that we can dynamically
  25  * add new files to /proc.
  26  *
  27  * parent/subdir are used for the directory structure (every /proc file has a
  28  * parent, but "subdir" is empty for all non-directory entries).
  29  * subdir_node is used to build the rb tree "subdir" of the parent.
  30  */
  31 struct proc_dir_entry {
  32         /*
  33          * number of callers into module in progress;
  34          * negative -> it's going away RSN
  35          */
  36         atomic_t in_use;
  37         refcount_t refcnt;
  38         struct list_head pde_openers;   /* who did ->open, but not ->release */
  39         /* protects ->pde_openers and all struct pde_opener instances */
  40         spinlock_t pde_unload_lock;
  41         struct completion *pde_unload_completion;
  42         const struct inode_operations *proc_iops;
  43         union {
  44                 const struct proc_ops *proc_ops;
  45                 const struct file_operations *proc_dir_ops;
  46         };
  47         const struct dentry_operations *proc_dops;
  48         union {
  49                 const struct seq_operations *seq_ops;
  50                 int (*single_show)(struct seq_file *, void *);
  51         };
  52         proc_write_t write;
  53         void *data;
  54         unsigned int state_size;
  55         unsigned int low_ino;
  56         nlink_t nlink;
  57         kuid_t uid;
  58         kgid_t gid;
  59         loff_t size;
  60         struct proc_dir_entry *parent;
  61         struct rb_root subdir;
  62         struct rb_node subdir_node;
  63         char *name;
  64         umode_t mode;
  65         u8 flags;
  66         u8 namelen;
  67         char inline_name[];
  68 } __randomize_layout;
  69
  70 #define SIZEOF_PDE      (                               \
  71         sizeof(struct proc_dir_entry) < 128 ? 128 :     \
  72         sizeof(struct proc_dir_entry) < 192 ? 192 :     \
  73         sizeof(struct proc_dir_entry) < 256 ? 256 :     \
  74         sizeof(struct proc_dir_entry) < 512 ? 512 :     \
  75         0)
  76 #define SIZEOF_PDE_INLINE_NAME (SIZEOF_PDE - sizeof(struct proc_dir_entry))
  77
  78 static inline bool pde_is_permanent(const struct proc_dir_entry *pde)
  79 {
  80         return pde->flags & PROC_ENTRY_PERMANENT;
  81 }
  82
  83 static inline void pde_make_permanent(struct proc_dir_entry *pde)
  84 {
  85         pde->flags |= PROC_ENTRY_PERMANENT;
  86 }
  87
  88 extern struct kmem_cache *proc_dir_entry_cache;
  89 void pde_free(struct proc_dir_entry *pde);
  90
  91 union proc_op {
  92         int (*proc_get_link)(struct dentry *, struct path *);
  93         int (*proc_show)(struct seq_file *m,
  94                 struct pid_namespace *ns, struct pid *pid,
  95                 struct task_struct *task);
  96         int lsmid;
  97 };
  98
  99 struct proc_inode {
 100         struct pid *pid;
 101         unsigned int fd;
 102         union proc_op op;
 103         struct proc_dir_entry *pde;
 104         struct ctl_table_header *sysctl;
 105         struct ctl_table *sysctl_entry;
 106         struct hlist_node sibling_inodes;
 107         const struct proc_ns_operations *ns_ops;
 108         struct inode vfs_inode;
 109 } __randomize_layout;
 110
 111 /*
 112  * General functions
 113  */
 114 static inline struct proc_inode *PROC_I(const struct inode *inode)
 115 {
 116         return container_of(inode, struct proc_inode, vfs_inode);
 117 }
 118
 119 static inline struct proc_dir_entry *PDE(const struct inode *inode)
 120 {
 121         return PROC_I(inode)->pde;
 122 }
 123
 124 static inline struct pid *proc_pid(const struct inode *inode)
 125 {
 126         return PROC_I(inode)->pid;
 127 }
 128
 129 static inline struct task_struct *get_proc_task(const struct inode *inode)
 130 {
 131         return get_pid_task(proc_pid(inode), PIDTYPE_PID);
 132 }
 133
 134 void task_dump_owner(struct task_struct *task, umode_t mode,
 135                      kuid_t *ruid, kgid_t *rgid);
 136
 137 unsigned name_to_int(const struct qstr *qstr);
 138 /*
 139  * Offset of the first process in the /proc root directory..
 140  */
 141 #define FIRST_PROCESS_ENTRY 256
 142
 143 /* Worst case buffer size needed for holding an integer. */
 144 #define PROC_NUMBUF 13
 145
 146 /**
 147  * folio_precise_page_mapcount() - Number of mappings of this folio page.
 148  * @folio: The folio.
 149  * @page: The page.
 150  *
 151  * The number of present user page table entries that reference this page
 152  * as tracked via the RMAP: either referenced directly (PTE) or as part of
 153  * a larger area that covers this page (e.g., PMD).
 154  *
 155  * Use this function only for the calculation of existing statistics
 156  * (USS, PSS, mapcount_max) and for debugging purposes (/proc/kpagecount).
 157  *
 158  * Do not add new users.
 159  *
 160  * Returns: The number of mappings of this folio page. 0 for
 161  * folios that are not mapped to user space or are not tracked via the RMAP
 162  * (e.g., shared zeropage).
 163  */
 164 static inline int folio_precise_page_mapcount(struct folio *folio,
 165                 struct page *page)
 166 {
 167         int mapcount = atomic_read(&page->_mapcount) + 1;
 168
 169         if (page_mapcount_is_type(mapcount))
 170                 mapcount = 0;
 171         if (folio_test_large(folio))
 172                 mapcount += folio_entire_mapcount(folio);
 173
 174         return mapcount;
 175 }
 176
 177 /*
 178  * array.c
 179  */
 180 extern const struct file_operations proc_tid_children_operations;
 181
 182 extern void proc_task_name(struct seq_file *m, struct task_struct *p,
 183                            bool escape);
 184 extern int proc_tid_stat(struct seq_file *, struct pid_namespace *,
 185                          struct pid *, struct task_struct *);
 186 extern int proc_tgid_stat(struct seq_file *, struct pid_namespace *,
 187                           struct pid *, struct task_struct *);
 188 extern int proc_pid_status(struct seq_file *, struct pid_namespace *,
 189                            struct pid *, struct task_struct *);
 190 extern int proc_pid_statm(struct seq_file *, struct pid_namespace *,
 191                           struct pid *, struct task_struct *);
 192
 193 /*
 194  * base.c
 195  */
 196 extern const struct dentry_operations pid_dentry_operations;
 197 extern int pid_getattr(struct mnt_idmap *, const struct path *,
 198                        struct kstat *, u32, unsigned int);
 199 extern int proc_setattr(struct mnt_idmap *, struct dentry *,
 200                         struct iattr *);
 201 extern void proc_pid_evict_inode(struct proc_inode *);
 202 extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t);
 203 extern void pid_update_inode(struct task_struct *, struct inode *);
 204 extern int pid_delete_dentry(const struct dentry *);
 205 extern int proc_pid_readdir(struct file *, struct dir_context *);
 206 struct dentry *proc_pid_lookup(struct dentry *, unsigned int);
 207 extern loff_t mem_lseek(struct file *, loff_t, int);
 208
 209 /* Lookups */
 210 typedef struct dentry *instantiate_t(struct dentry *,
 211                                      struct task_struct *, const void *);
 212 bool proc_fill_cache(struct file *, struct dir_context *, const char *, unsigned int,
 213                            instantiate_t, struct task_struct *, const void *);
 214
 215 /*
 216  * generic.c
 217  */
 218 struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
 219                 struct proc_dir_entry **parent, void *data);
 220 struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
 221                 struct proc_dir_entry *dp);
 222 extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int);
 223 struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *);
 224 extern int proc_readdir(struct file *, struct dir_context *);
 225 int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *);
 226
 227 static inline void pde_get(struct proc_dir_entry *pde)
 228 {
 229         refcount_inc(&pde->refcnt);
 230 }
 231 extern void pde_put(struct proc_dir_entry *);
 232
 233 static inline bool is_empty_pde(const struct proc_dir_entry *pde)
 234 {
 235         return S_ISDIR(pde->mode) && !pde->proc_iops;
 236 }
 237 extern ssize_t proc_simple_write(struct file *, const char __user *, size_t, loff_t *);
 238
 239 /*
 240  * inode.c
 241  */
 242 struct pde_opener {
 243         struct list_head lh;
 244         struct file *file;
 245         bool closing;
 246         struct completion *c;
 247 } __randomize_layout;
 248 extern const struct inode_operations proc_link_inode_operations;
 249 extern const struct inode_operations proc_pid_link_inode_operations;
 250 extern const struct super_operations proc_sops;
 251
 252 void proc_init_kmemcache(void);
 253 void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock);
 254 void set_proc_pid_nlink(void);
 255 extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
 256 extern void proc_entry_rundown(struct proc_dir_entry *);
 257
 258 /*
 259  * proc_namespaces.c
 260  */
 261 extern const struct inode_operations proc_ns_dir_inode_operations;
 262 extern const struct file_operations proc_ns_dir_operations;
 263
 264 /*
 265  * proc_net.c
 266  */
 267 extern const struct file_operations proc_net_operations;
 268 extern const struct inode_operations proc_net_inode_operations;
 269
 270 #ifdef CONFIG_NET
 271 extern int proc_net_init(void);
 272 #else
 273 static inline int proc_net_init(void) { return 0; }
 274 #endif
 275
 276 /*
 277  * proc_self.c
 278  */
 279 extern int proc_setup_self(struct super_block *);
 280
 281 /*
 282  * proc_thread_self.c
 283  */
 284 extern int proc_setup_thread_self(struct super_block *);
 285 extern void proc_thread_self_init(void);
 286
 287 /*
 288  * proc_sysctl.c
 289  */
 290 #ifdef CONFIG_PROC_SYSCTL
 291 extern int proc_sys_init(void);
 292 extern void proc_sys_evict_inode(struct inode *inode,
 293                                  struct ctl_table_header *head);
 294 #else
 295 static inline void proc_sys_init(void) { }
 296 static inline void proc_sys_evict_inode(struct  inode *inode,
 297                                         struct ctl_table_header *head) { }
 298 #endif
 299
 300 /*
 301  * proc_tty.c
 302  */
 303 #ifdef CONFIG_TTY
 304 extern void proc_tty_init(void);
 305 #else
 306 static inline void proc_tty_init(void) {}
 307 #endif
 308
 309 /*
 310  * root.c
 311  */
 312 extern struct proc_dir_entry proc_root;
 313
 314 extern void proc_self_init(void);
 315
 316 /*
 317  * task_[no]mmu.c
 318  */
 319 struct mem_size_stats;
 320 struct proc_maps_private {
 321         struct inode *inode;
 322         struct task_struct *task;
 323         struct mm_struct *mm;
 324         struct vma_iterator iter;
 325 #ifdef CONFIG_NUMA
 326         struct mempolicy *task_mempolicy;
 327 #endif
 328 } __randomize_layout;
 329
 330 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode);
 331
 332 extern const struct file_operations proc_pid_maps_operations;
 333 extern const struct file_operations proc_pid_numa_maps_operations;
 334 extern const struct file_operations proc_pid_smaps_operations;
 335 extern const struct file_operations proc_pid_smaps_rollup_operations;
 336 extern const struct file_operations proc_clear_refs_operations;
 337 extern const struct file_operations proc_pagemap_operations;
 338
 339 extern unsigned long task_vsize(struct mm_struct *);
 340 extern unsigned long task_statm(struct mm_struct *,
 341                                 unsigned long *, unsigned long *,
 342                                 unsigned long *, unsigned long *);
 343 extern void task_mem(struct seq_file *, struct mm_struct *);
 344
 345 extern const struct dentry_operations proc_net_dentry_ops;
 346 static inline void pde_force_lookup(struct proc_dir_entry *pde)
 347 {
 348         /* /proc/net/ entries can be changed under us by setns(CLONE_NEWNET) */
 349         pde->proc_dops = &proc_net_dentry_ops;
 350 }
 351
 352 /*
 353  * Add a new procfs dentry that can't serve as a mountpoint. That should
 354  * encompass anything that is ephemeral and can just disappear while the
 355  * process is still around.
 356  */
 357 static inline struct dentry *proc_splice_unmountable(struct inode *inode,
 358                 struct dentry *dentry, const struct dentry_operations *d_ops)
 359 {
 360         d_set_d_op(dentry, d_ops);
 361         dont_mount(dentry);
 362         return d_splice_alias(inode, dentry);
 363 }