Line data Source code
1 : /* SPDX-License-Identifier: GPL-2.0 */
2 : /*
3 : * sysctl.h: General linux system control interface
4 : *
5 : * Begun 24 March 1995, Stephen Tweedie
6 : *
7 : ****************************************************************
8 : ****************************************************************
9 : **
10 : ** WARNING:
11 : ** The values in this file are exported to user space via
12 : ** the sysctl() binary interface. Do *NOT* change the
13 : ** numbering of any existing values here, and do not change
14 : ** any numbers within any one set of values. If you have to
15 : ** redefine an existing interface, use a new number for it.
16 : ** The kernel will then return -ENOTDIR to any application using
17 : ** the old binary interface.
18 : **
19 : ****************************************************************
20 : ****************************************************************
21 : */
22 : #ifndef _LINUX_SYSCTL_H
23 : #define _LINUX_SYSCTL_H
24 :
25 : #include <linux/list.h>
26 : #include <linux/rcupdate.h>
27 : #include <linux/wait.h>
28 : #include <linux/rbtree.h>
29 : #include <linux/uidgid.h>
30 : #include <uapi/linux/sysctl.h>
31 :
32 : /* For the /proc/sys support */
33 : struct completion;
34 : struct ctl_table;
35 : struct nsproxy;
36 : struct ctl_table_root;
37 : struct ctl_table_header;
38 : struct ctl_dir;
39 :
40 : /* Keep the same order as in fs/proc/proc_sysctl.c */
41 : #define SYSCTL_ZERO ((void *)&sysctl_vals[0])
42 : #define SYSCTL_ONE ((void *)&sysctl_vals[1])
43 : #define SYSCTL_TWO ((void *)&sysctl_vals[2])
44 : #define SYSCTL_THREE ((void *)&sysctl_vals[3])
45 : #define SYSCTL_FOUR ((void *)&sysctl_vals[4])
46 : #define SYSCTL_ONE_HUNDRED ((void *)&sysctl_vals[5])
47 : #define SYSCTL_TWO_HUNDRED ((void *)&sysctl_vals[6])
48 : #define SYSCTL_ONE_THOUSAND ((void *)&sysctl_vals[7])
49 : #define SYSCTL_THREE_THOUSAND ((void *)&sysctl_vals[8])
50 : #define SYSCTL_INT_MAX ((void *)&sysctl_vals[9])
51 :
52 : /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
53 : #define SYSCTL_MAXOLDUID ((void *)&sysctl_vals[10])
54 : #define SYSCTL_NEG_ONE ((void *)&sysctl_vals[11])
55 :
56 : extern const int sysctl_vals[];
57 :
58 : #define SYSCTL_LONG_ZERO ((void *)&sysctl_long_vals[0])
59 : #define SYSCTL_LONG_ONE ((void *)&sysctl_long_vals[1])
60 : #define SYSCTL_LONG_MAX ((void *)&sysctl_long_vals[2])
61 :
62 : extern const unsigned long sysctl_long_vals[];
63 :
64 : typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer,
65 : size_t *lenp, loff_t *ppos);
66 :
67 : int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *);
68 : int proc_dobool(struct ctl_table *table, int write, void *buffer,
69 : size_t *lenp, loff_t *ppos);
70 : int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *);
71 : int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *);
72 : int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
73 : int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer,
74 : size_t *lenp, loff_t *ppos);
75 : int proc_dou8vec_minmax(struct ctl_table *table, int write, void *buffer,
76 : size_t *lenp, loff_t *ppos);
77 : int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *);
78 : int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write,
79 : void *buffer, size_t *lenp, loff_t *ppos);
80 : int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *,
81 : loff_t *);
82 : int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *,
83 : loff_t *);
84 : int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
85 : int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *,
86 : size_t *, loff_t *);
87 : int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *);
88 : int proc_do_static_key(struct ctl_table *table, int write, void *buffer,
89 : size_t *lenp, loff_t *ppos);
90 :
91 : /*
92 : * Register a set of sysctl names by calling register_sysctl_table
93 : * with an initialised array of struct ctl_table's. An entry with
94 : * NULL procname terminates the table. table->de will be
95 : * set up by the registration and need not be initialised in advance.
96 : *
97 : * sysctl names can be mirrored automatically under /proc/sys. The
98 : * procname supplied controls /proc naming.
99 : *
100 : * The table's mode will be honoured for proc-fs access.
101 : *
102 : * Leaf nodes in the sysctl tree will be represented by a single file
103 : * under /proc; non-leaf nodes will be represented by directories. A
104 : * null procname disables /proc mirroring at this node.
105 : *
106 : * The data and maxlen fields of the ctl_table
107 : * struct enable minimal validation of the values being written to be
108 : * performed, and the mode field allows minimal authentication.
109 : *
110 : * There must be a proc_handler routine for any terminal nodes
111 : * mirrored under /proc/sys (non-terminals are handled by a built-in
112 : * directory handler). Several default handlers are available to
113 : * cover common cases.
114 : */
115 :
116 : /* Support for userspace poll() to watch for changes */
117 : struct ctl_table_poll {
118 : atomic_t event;
119 : wait_queue_head_t wait;
120 : };
121 :
122 : static inline void *proc_sys_poll_event(struct ctl_table_poll *poll)
123 : {
124 0 : return (void *)(unsigned long)atomic_read(&poll->event);
125 : }
126 :
127 : #define __CTL_TABLE_POLL_INITIALIZER(name) { \
128 : .event = ATOMIC_INIT(0), \
129 : .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) }
130 :
131 : #define DEFINE_CTL_TABLE_POLL(name) \
132 : struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name)
133 :
134 : /* A sysctl table is an array of struct ctl_table: */
135 : struct ctl_table {
136 : const char *procname; /* Text ID for /proc/sys, or zero */
137 : void *data;
138 : int maxlen;
139 : umode_t mode;
140 : struct ctl_table *child; /* Deprecated */
141 : proc_handler *proc_handler; /* Callback for text formatting */
142 : struct ctl_table_poll *poll;
143 : void *extra1;
144 : void *extra2;
145 : } __randomize_layout;
146 :
147 : struct ctl_node {
148 : struct rb_node node;
149 : struct ctl_table_header *header;
150 : };
151 :
152 : /* struct ctl_table_header is used to maintain dynamic lists of
153 : struct ctl_table trees. */
154 : struct ctl_table_header {
155 : union {
156 : struct {
157 : struct ctl_table *ctl_table;
158 : int used;
159 : int count;
160 : int nreg;
161 : };
162 : struct rcu_head rcu;
163 : };
164 : struct completion *unregistering;
165 : struct ctl_table *ctl_table_arg;
166 : struct ctl_table_root *root;
167 : struct ctl_table_set *set;
168 : struct ctl_dir *parent;
169 : struct ctl_node *node;
170 : struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */
171 : };
172 :
173 : struct ctl_dir {
174 : /* Header must be at the start of ctl_dir */
175 : struct ctl_table_header header;
176 : struct rb_root root;
177 : };
178 :
179 : struct ctl_table_set {
180 : int (*is_seen)(struct ctl_table_set *);
181 : struct ctl_dir dir;
182 : };
183 :
184 : struct ctl_table_root {
185 : struct ctl_table_set default_set;
186 : struct ctl_table_set *(*lookup)(struct ctl_table_root *root);
187 : void (*set_ownership)(struct ctl_table_header *head,
188 : struct ctl_table *table,
189 : kuid_t *uid, kgid_t *gid);
190 : int (*permissions)(struct ctl_table_header *head, struct ctl_table *table);
191 : };
192 :
193 : /* struct ctl_path describes where in the hierarchy a table is added */
194 : struct ctl_path {
195 : const char *procname;
196 : };
197 :
198 : #ifdef CONFIG_SYSCTL
199 :
200 : #define DECLARE_SYSCTL_BASE(_name, _table) \
201 : static struct ctl_table _name##_base_table[] = { \
202 : { \
203 : .procname = #_name, \
204 : .mode = 0555, \
205 : .child = _table, \
206 : }, \
207 : { }, \
208 : }
209 :
210 : extern int __register_sysctl_base(struct ctl_table *base_table);
211 :
212 : #define register_sysctl_base(_name) __register_sysctl_base(_name##_base_table)
213 :
214 : void proc_sys_poll_notify(struct ctl_table_poll *poll);
215 :
216 : extern void setup_sysctl_set(struct ctl_table_set *p,
217 : struct ctl_table_root *root,
218 : int (*is_seen)(struct ctl_table_set *));
219 : extern void retire_sysctl_set(struct ctl_table_set *set);
220 :
221 : struct ctl_table_header *__register_sysctl_table(
222 : struct ctl_table_set *set,
223 : const char *path, struct ctl_table *table);
224 : struct ctl_table_header *__register_sysctl_paths(
225 : struct ctl_table_set *set,
226 : const struct ctl_path *path, struct ctl_table *table);
227 : struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table);
228 : struct ctl_table_header *register_sysctl_table(struct ctl_table * table);
229 : struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
230 : struct ctl_table *table);
231 :
232 : void unregister_sysctl_table(struct ctl_table_header * table);
233 :
234 : extern int sysctl_init_bases(void);
235 : extern void __register_sysctl_init(const char *path, struct ctl_table *table,
236 : const char *table_name);
237 : #define register_sysctl_init(path, table) __register_sysctl_init(path, table, #table)
238 : extern struct ctl_table_header *register_sysctl_mount_point(const char *path);
239 :
240 : void do_sysctl_args(void);
241 : int do_proc_douintvec(struct ctl_table *table, int write,
242 : void *buffer, size_t *lenp, loff_t *ppos,
243 : int (*conv)(unsigned long *lvalp,
244 : unsigned int *valp,
245 : int write, void *data),
246 : void *data);
247 :
248 : extern int pwrsw_enabled;
249 : extern int unaligned_enabled;
250 : extern int unaligned_dump_stack;
251 : extern int no_unaligned_warning;
252 :
253 : extern struct ctl_table sysctl_mount_point[];
254 :
255 : #else /* CONFIG_SYSCTL */
256 :
257 : #define DECLARE_SYSCTL_BASE(_name, _table)
258 :
259 : static inline int __register_sysctl_base(struct ctl_table *base_table)
260 : {
261 : return 0;
262 : }
263 :
264 : #define register_sysctl_base(table) __register_sysctl_base(table)
265 :
266 : static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
267 : {
268 : return NULL;
269 : }
270 :
271 : static inline void register_sysctl_init(const char *path, struct ctl_table *table)
272 : {
273 : }
274 :
275 : static inline struct ctl_table_header *register_sysctl_mount_point(const char *path)
276 : {
277 : return NULL;
278 : }
279 :
280 : static inline struct ctl_table_header *register_sysctl_paths(
281 : const struct ctl_path *path, struct ctl_table *table)
282 : {
283 : return NULL;
284 : }
285 :
286 : static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table)
287 : {
288 : return NULL;
289 : }
290 :
291 : static inline void unregister_sysctl_table(struct ctl_table_header * table)
292 : {
293 : }
294 :
295 : static inline void setup_sysctl_set(struct ctl_table_set *p,
296 : struct ctl_table_root *root,
297 : int (*is_seen)(struct ctl_table_set *))
298 : {
299 : }
300 :
301 : static inline void do_sysctl_args(void)
302 : {
303 : }
304 : #endif /* CONFIG_SYSCTL */
305 :
306 : int sysctl_max_threads(struct ctl_table *table, int write, void *buffer,
307 : size_t *lenp, loff_t *ppos);
308 :
309 : #endif /* _LINUX_SYSCTL_H */
|
