Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
18struct ctl_table_header;
19struct 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 */
31struct 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
78static inline bool pde_is_permanent(const struct proc_dir_entry *pde)
79{
80 return pde->flags & PROC_ENTRY_PERMANENT;
81}
82
83static inline void pde_make_permanent(struct proc_dir_entry *pde)
84{
85 pde->flags |= PROC_ENTRY_PERMANENT;
86}
87
88static inline bool pde_has_proc_read_iter(const struct proc_dir_entry *pde)
89{
90 return pde->flags & PROC_ENTRY_proc_read_iter;
91}
92
93static inline bool pde_has_proc_compat_ioctl(const struct proc_dir_entry *pde)
94{
95#ifdef CONFIG_COMPAT
96 return pde->flags & PROC_ENTRY_proc_compat_ioctl;
97#else
98 return false;
99#endif
100}
101
102extern struct kmem_cache *proc_dir_entry_cache;
103void pde_free(struct proc_dir_entry *pde);
104
105union proc_op {
106 int (*proc_get_link)(struct dentry *, struct path *);
107 int (*proc_show)(struct seq_file *m,
108 struct pid_namespace *ns, struct pid *pid,
109 struct task_struct *task);
110 int lsmid;
111};
112
113struct proc_inode {
114 struct pid *pid;
115 unsigned int fd;
116 union proc_op op;
117 struct proc_dir_entry *pde;
118 struct ctl_table_header *sysctl;
119 const struct ctl_table *sysctl_entry;
120 struct hlist_node sibling_inodes;
121 const struct proc_ns_operations *ns_ops;
122 struct inode vfs_inode;
123} __randomize_layout;
124
125/*
126 * General functions
127 */
128static inline struct proc_inode *PROC_I(const struct inode *inode)
129{
130 return container_of(inode, struct proc_inode, vfs_inode);
131}
132
133static inline struct proc_dir_entry *PDE(const struct inode *inode)
134{
135 return PROC_I(inode)->pde;
136}
137
138static inline struct pid *proc_pid(const struct inode *inode)
139{
140 return PROC_I(inode)->pid;
141}
142
143static inline struct task_struct *get_proc_task(const struct inode *inode)
144{
145 return get_pid_task(proc_pid(inode), PIDTYPE_PID);
146}
147
148void task_dump_owner(struct task_struct *task, umode_t mode,
149 kuid_t *ruid, kgid_t *rgid);
150
151unsigned name_to_int(const struct qstr *qstr);
152/*
153 * Offset of the first process in the /proc root directory..
154 */
155#define FIRST_PROCESS_ENTRY 256
156
157/* Worst case buffer size needed for holding an integer. */
158#define PROC_NUMBUF 13
159
160#ifdef CONFIG_PAGE_MAPCOUNT
161/**
162 * folio_precise_page_mapcount() - Number of mappings of this folio page.
163 * @folio: The folio.
164 * @page: The page.
165 *
166 * The number of present user page table entries that reference this page
167 * as tracked via the RMAP: either referenced directly (PTE) or as part of
168 * a larger area that covers this page (e.g., PMD).
169 *
170 * Use this function only for the calculation of existing statistics
171 * (USS, PSS, mapcount_max) and for debugging purposes (/proc/kpagecount).
172 *
173 * Do not add new users.
174 *
175 * Returns: The number of mappings of this folio page. 0 for
176 * folios that are not mapped to user space or are not tracked via the RMAP
177 * (e.g., shared zeropage).
178 */
179static inline int folio_precise_page_mapcount(struct folio *folio,
180 struct page *page)
181{
182 int mapcount = atomic_read(&page->_mapcount) + 1;
183
184 if (page_mapcount_is_type(mapcount))
185 mapcount = 0;
186 if (folio_test_large(folio))
187 mapcount += folio_entire_mapcount(folio);
188
189 return mapcount;
190}
191#else /* !CONFIG_PAGE_MAPCOUNT */
192static inline int folio_precise_page_mapcount(struct folio *folio,
193 struct page *page)
194{
195 BUILD_BUG();
196}
197#endif /* CONFIG_PAGE_MAPCOUNT */
198
199/**
200 * folio_average_page_mapcount() - Average number of mappings per page in this
201 * folio
202 * @folio: The folio.
203 *
204 * The average number of user page table entries that reference each page in
205 * this folio as tracked via the RMAP: either referenced directly (PTE) or
206 * as part of a larger area that covers this page (e.g., PMD).
207 *
208 * The average is calculated by rounding to the nearest integer; however,
209 * to avoid duplicated code in current callers, the average is at least
210 * 1 if any page of the folio is mapped.
211 *
212 * Returns: The average number of mappings per page in this folio.
213 */
214static inline int folio_average_page_mapcount(struct folio *folio)
215{
216 int mapcount, entire_mapcount, avg;
217
218 if (!folio_test_large(folio))
219 return atomic_read(&folio->_mapcount) + 1;
220
221 mapcount = folio_large_mapcount(folio);
222 if (unlikely(mapcount <= 0))
223 return 0;
224 entire_mapcount = folio_entire_mapcount(folio);
225 if (mapcount <= entire_mapcount)
226 return entire_mapcount;
227 mapcount -= entire_mapcount;
228
229 /* Round to closest integer ... */
230 avg = ((unsigned int)mapcount + folio_large_nr_pages(folio) / 2) >> folio_large_order(folio);
231 /* ... but return at least 1. */
232 return max_t(int, avg + entire_mapcount, 1);
233}
234/*
235 * array.c
236 */
237extern const struct file_operations proc_tid_children_operations;
238
239extern void proc_task_name(struct seq_file *m, struct task_struct *p,
240 bool escape);
241extern int proc_tid_stat(struct seq_file *, struct pid_namespace *,
242 struct pid *, struct task_struct *);
243extern int proc_tgid_stat(struct seq_file *, struct pid_namespace *,
244 struct pid *, struct task_struct *);
245extern int proc_pid_status(struct seq_file *, struct pid_namespace *,
246 struct pid *, struct task_struct *);
247extern int proc_pid_statm(struct seq_file *, struct pid_namespace *,
248 struct pid *, struct task_struct *);
249
250/*
251 * base.c
252 */
253extern const struct dentry_operations pid_dentry_operations;
254extern int pid_getattr(struct mnt_idmap *, const struct path *,
255 struct kstat *, u32, unsigned int);
256extern int proc_setattr(struct mnt_idmap *, struct dentry *,
257 struct iattr *);
258extern void proc_pid_evict_inode(struct proc_inode *);
259extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t);
260extern void pid_update_inode(struct task_struct *, struct inode *);
261extern int pid_delete_dentry(const struct dentry *);
262extern int proc_pid_readdir(struct file *, struct dir_context *);
263struct dentry *proc_pid_lookup(struct dentry *, unsigned int);
264extern loff_t mem_lseek(struct file *, loff_t, int);
265
266/* Lookups */
267typedef struct dentry *instantiate_t(struct dentry *,
268 struct task_struct *, const void *);
269bool proc_fill_cache(struct file *, struct dir_context *, const char *, unsigned int,
270 instantiate_t, struct task_struct *, const void *);
271
272/*
273 * generic.c
274 */
275struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
276 struct proc_dir_entry **parent, void *data);
277struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
278 struct proc_dir_entry *dp);
279extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int);
280struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *);
281extern int proc_readdir(struct file *, struct dir_context *);
282int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *);
283
284static inline void pde_get(struct proc_dir_entry *pde)
285{
286 refcount_inc(&pde->refcnt);
287}
288extern void pde_put(struct proc_dir_entry *);
289
290static inline bool is_empty_pde(const struct proc_dir_entry *pde)
291{
292 return S_ISDIR(pde->mode) && !pde->proc_iops;
293}
294extern ssize_t proc_simple_write(struct file *, const char __user *, size_t, loff_t *);
295
296/*
297 * inode.c
298 */
299struct pde_opener {
300 struct list_head lh;
301 struct file *file;
302 bool closing;
303 struct completion *c;
304} __randomize_layout;
305extern const struct inode_operations proc_link_inode_operations;
306extern const struct inode_operations proc_pid_link_inode_operations;
307extern const struct super_operations proc_sops;
308
309void proc_init_kmemcache(void);
310void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock);
311void set_proc_pid_nlink(void);
312extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
313extern void proc_entry_rundown(struct proc_dir_entry *);
314
315/*
316 * proc_namespaces.c
317 */
318extern const struct inode_operations proc_ns_dir_inode_operations;
319extern const struct file_operations proc_ns_dir_operations;
320
321/*
322 * proc_net.c
323 */
324extern const struct file_operations proc_net_operations;
325extern const struct inode_operations proc_net_inode_operations;
326
327#ifdef CONFIG_NET
328extern int proc_net_init(void);
329#else
330static inline int proc_net_init(void) { return 0; }
331#endif
332
333/*
334 * proc_self.c
335 */
336extern int proc_setup_self(struct super_block *);
337
338/*
339 * proc_thread_self.c
340 */
341extern int proc_setup_thread_self(struct super_block *);
342extern void proc_thread_self_init(void);
343
344/*
345 * proc_sysctl.c
346 */
347#ifdef CONFIG_PROC_SYSCTL
348extern int proc_sys_init(void);
349extern void proc_sys_evict_inode(struct inode *inode,
350 struct ctl_table_header *head);
351#else
352static inline void proc_sys_init(void) { }
353static inline void proc_sys_evict_inode(struct inode *inode,
354 struct ctl_table_header *head) { }
355#endif
356
357/*
358 * proc_tty.c
359 */
360#ifdef CONFIG_TTY
361extern void proc_tty_init(void);
362#else
363static inline void proc_tty_init(void) {}
364#endif
365
366/*
367 * root.c
368 */
369extern struct proc_dir_entry proc_root;
370
371extern void proc_self_init(void);
372
373/*
374 * task_[no]mmu.c
375 */
376struct mem_size_stats;
377struct proc_maps_private {
378 struct inode *inode;
379 struct task_struct *task;
380 struct mm_struct *mm;
381 struct vma_iterator iter;
382#ifdef CONFIG_NUMA
383 struct mempolicy *task_mempolicy;
384#endif
385} __randomize_layout;
386
387struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode);
388
389extern const struct file_operations proc_pid_maps_operations;
390extern const struct file_operations proc_pid_numa_maps_operations;
391extern const struct file_operations proc_pid_smaps_operations;
392extern const struct file_operations proc_pid_smaps_rollup_operations;
393extern const struct file_operations proc_clear_refs_operations;
394extern const struct file_operations proc_pagemap_operations;
395
396extern unsigned long task_vsize(struct mm_struct *);
397extern unsigned long task_statm(struct mm_struct *,
398 unsigned long *, unsigned long *,
399 unsigned long *, unsigned long *);
400extern void task_mem(struct seq_file *, struct mm_struct *);
401
402extern const struct dentry_operations proc_net_dentry_ops;
403static inline void pde_force_lookup(struct proc_dir_entry *pde)
404{
405 /* /proc/net/ entries can be changed under us by setns(CLONE_NEWNET) */
406 pde->proc_dops = &proc_net_dentry_ops;
407}
408
409/*
410 * Add a new procfs dentry that can't serve as a mountpoint. That should
411 * encompass anything that is ephemeral and can just disappear while the
412 * process is still around.
413 */
414static inline struct dentry *proc_splice_unmountable(struct inode *inode,
415 struct dentry *dentry, const struct dentry_operations *d_ops)
416{
417 d_set_d_op(dentry, d_ops);
418 dont_mount(dentry);
419 return d_splice_alias(inode, dentry);
420}