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
pde_is_permanent(const struct proc_dir_entry * pde)78 static inline bool pde_is_permanent(const struct proc_dir_entry *pde)
79 {
80 return pde->flags & PROC_ENTRY_PERMANENT;
81 }
82
pde_make_permanent(struct proc_dir_entry * pde)83 static inline void pde_make_permanent(struct proc_dir_entry *pde)
84 {
85 pde->flags |= PROC_ENTRY_PERMANENT;
86 }
87
pde_has_proc_read_iter(const struct proc_dir_entry * pde)88 static 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
pde_has_proc_compat_ioctl(const struct proc_dir_entry * pde)93 static 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
102 extern struct kmem_cache *proc_dir_entry_cache;
103 void pde_free(struct proc_dir_entry *pde);
104
105 union 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
113 struct 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 */
PROC_I(const struct inode * inode)128 static inline struct proc_inode *PROC_I(const struct inode *inode)
129 {
130 return container_of(inode, struct proc_inode, vfs_inode);
131 }
132
PDE(const struct inode * inode)133 static inline struct proc_dir_entry *PDE(const struct inode *inode)
134 {
135 return PROC_I(inode)->pde;
136 }
137
proc_pid(const struct inode * inode)138 static inline struct pid *proc_pid(const struct inode *inode)
139 {
140 return PROC_I(inode)->pid;
141 }
142
get_proc_task(const struct inode * inode)143 static inline struct task_struct *get_proc_task(const struct inode *inode)
144 {
145 return get_pid_task(proc_pid(inode), PIDTYPE_PID);
146 }
147
148 void task_dump_owner(struct task_struct *task, umode_t mode,
149 kuid_t *ruid, kgid_t *rgid);
150
151 unsigned 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 /**
161 * folio_precise_page_mapcount() - Number of mappings of this folio page.
162 * @folio: The folio.
163 * @page: The page.
164 *
165 * The number of present user page table entries that reference this page
166 * as tracked via the RMAP: either referenced directly (PTE) or as part of
167 * a larger area that covers this page (e.g., PMD).
168 *
169 * Use this function only for the calculation of existing statistics
170 * (USS, PSS, mapcount_max) and for debugging purposes (/proc/kpagecount).
171 *
172 * Do not add new users.
173 *
174 * Returns: The number of mappings of this folio page. 0 for
175 * folios that are not mapped to user space or are not tracked via the RMAP
176 * (e.g., shared zeropage).
177 */
folio_precise_page_mapcount(struct folio * folio,struct page * page)178 static inline int folio_precise_page_mapcount(struct folio *folio,
179 struct page *page)
180 {
181 int mapcount = atomic_read(&page->_mapcount) + 1;
182
183 if (page_mapcount_is_type(mapcount))
184 mapcount = 0;
185 if (folio_test_large(folio))
186 mapcount += folio_entire_mapcount(folio);
187
188 return mapcount;
189 }
190
191 /*
192 * array.c
193 */
194 extern const struct file_operations proc_tid_children_operations;
195
196 extern void proc_task_name(struct seq_file *m, struct task_struct *p,
197 bool escape);
198 extern int proc_tid_stat(struct seq_file *, struct pid_namespace *,
199 struct pid *, struct task_struct *);
200 extern int proc_tgid_stat(struct seq_file *, struct pid_namespace *,
201 struct pid *, struct task_struct *);
202 extern int proc_pid_status(struct seq_file *, struct pid_namespace *,
203 struct pid *, struct task_struct *);
204 extern int proc_pid_statm(struct seq_file *, struct pid_namespace *,
205 struct pid *, struct task_struct *);
206
207 /*
208 * base.c
209 */
210 extern const struct dentry_operations pid_dentry_operations;
211 extern int pid_getattr(struct mnt_idmap *, const struct path *,
212 struct kstat *, u32, unsigned int);
213 extern int proc_setattr(struct mnt_idmap *, struct dentry *,
214 struct iattr *);
215 extern void proc_pid_evict_inode(struct proc_inode *);
216 extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t);
217 extern void pid_update_inode(struct task_struct *, struct inode *);
218 extern int pid_delete_dentry(const struct dentry *);
219 extern int proc_pid_readdir(struct file *, struct dir_context *);
220 struct dentry *proc_pid_lookup(struct dentry *, unsigned int);
221 extern loff_t mem_lseek(struct file *, loff_t, int);
222
223 /* Lookups */
224 typedef struct dentry *instantiate_t(struct dentry *,
225 struct task_struct *, const void *);
226 bool proc_fill_cache(struct file *, struct dir_context *, const char *, unsigned int,
227 instantiate_t, struct task_struct *, const void *);
228
229 /*
230 * generic.c
231 */
232 struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
233 struct proc_dir_entry **parent, void *data);
234 struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
235 struct proc_dir_entry *dp);
236 extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int);
237 struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *);
238 extern int proc_readdir(struct file *, struct dir_context *);
239 int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *);
240
pde_get(struct proc_dir_entry * pde)241 static inline void pde_get(struct proc_dir_entry *pde)
242 {
243 refcount_inc(&pde->refcnt);
244 }
245 extern void pde_put(struct proc_dir_entry *);
246
is_empty_pde(const struct proc_dir_entry * pde)247 static inline bool is_empty_pde(const struct proc_dir_entry *pde)
248 {
249 return S_ISDIR(pde->mode) && !pde->proc_iops;
250 }
251 extern ssize_t proc_simple_write(struct file *, const char __user *, size_t, loff_t *);
252
253 /*
254 * inode.c
255 */
256 struct pde_opener {
257 struct list_head lh;
258 struct file *file;
259 bool closing;
260 struct completion *c;
261 } __randomize_layout;
262 extern const struct inode_operations proc_link_inode_operations;
263 extern const struct inode_operations proc_pid_link_inode_operations;
264 extern const struct super_operations proc_sops;
265
266 void proc_init_kmemcache(void);
267 void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock);
268 void set_proc_pid_nlink(void);
269 extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
270 extern void proc_entry_rundown(struct proc_dir_entry *);
271
272 /*
273 * proc_namespaces.c
274 */
275 extern const struct inode_operations proc_ns_dir_inode_operations;
276 extern const struct file_operations proc_ns_dir_operations;
277
278 /*
279 * proc_net.c
280 */
281 extern const struct file_operations proc_net_operations;
282 extern const struct inode_operations proc_net_inode_operations;
283
284 #ifdef CONFIG_NET
285 extern int proc_net_init(void);
286 #else
proc_net_init(void)287 static inline int proc_net_init(void) { return 0; }
288 #endif
289
290 /*
291 * proc_self.c
292 */
293 extern int proc_setup_self(struct super_block *);
294
295 /*
296 * proc_thread_self.c
297 */
298 extern int proc_setup_thread_self(struct super_block *);
299 extern void proc_thread_self_init(void);
300
301 /*
302 * proc_sysctl.c
303 */
304 #ifdef CONFIG_PROC_SYSCTL
305 extern int proc_sys_init(void);
306 extern void proc_sys_evict_inode(struct inode *inode,
307 struct ctl_table_header *head);
308 #else
proc_sys_init(void)309 static inline void proc_sys_init(void) { }
proc_sys_evict_inode(struct inode * inode,struct ctl_table_header * head)310 static inline void proc_sys_evict_inode(struct inode *inode,
311 struct ctl_table_header *head) { }
312 #endif
313
314 /*
315 * proc_tty.c
316 */
317 #ifdef CONFIG_TTY
318 extern void proc_tty_init(void);
319 #else
proc_tty_init(void)320 static inline void proc_tty_init(void) {}
321 #endif
322
323 /*
324 * root.c
325 */
326 extern struct proc_dir_entry proc_root;
327
328 extern void proc_self_init(void);
329
330 /*
331 * task_[no]mmu.c
332 */
333 struct mem_size_stats;
334 struct proc_maps_private {
335 struct inode *inode;
336 struct task_struct *task;
337 struct mm_struct *mm;
338 struct vma_iterator iter;
339 #ifdef CONFIG_NUMA
340 struct mempolicy *task_mempolicy;
341 #endif
342 } __randomize_layout;
343
344 struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode);
345
346 extern const struct file_operations proc_pid_maps_operations;
347 extern const struct file_operations proc_pid_numa_maps_operations;
348 extern const struct file_operations proc_pid_smaps_operations;
349 extern const struct file_operations proc_pid_smaps_rollup_operations;
350 extern const struct file_operations proc_clear_refs_operations;
351 extern const struct file_operations proc_pagemap_operations;
352
353 extern unsigned long task_vsize(struct mm_struct *);
354 extern unsigned long task_statm(struct mm_struct *,
355 unsigned long *, unsigned long *,
356 unsigned long *, unsigned long *);
357 extern void task_mem(struct seq_file *, struct mm_struct *);
358
359 extern const struct dentry_operations proc_net_dentry_ops;
pde_force_lookup(struct proc_dir_entry * pde)360 static inline void pde_force_lookup(struct proc_dir_entry *pde)
361 {
362 /* /proc/net/ entries can be changed under us by setns(CLONE_NEWNET) */
363 pde->proc_dops = &proc_net_dentry_ops;
364 }
365
366 /*
367 * Add a new procfs dentry that can't serve as a mountpoint. That should
368 * encompass anything that is ephemeral and can just disappear while the
369 * process is still around.
370 */
proc_splice_unmountable(struct inode * inode,struct dentry * dentry,const struct dentry_operations * d_ops)371 static inline struct dentry *proc_splice_unmountable(struct inode *inode,
372 struct dentry *dentry, const struct dentry_operations *d_ops)
373 {
374 d_set_d_op(dentry, d_ops);
375 dont_mount(dentry);
376 return d_splice_alias(inode, dentry);
377 }
378