summaryrefslogtreecommitdiff
path: root/include/linux/sysctl.h
blob: 180adf7da785c8c0a2ec2c595fd21f99c1d35b6c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * sysctl.h: General linux system control interface
 *
 * Begun 24 March 1995, Stephen Tweedie
 *
 ****************************************************************
 ****************************************************************
 **
 **  WARNING:
 **  The values in this file are exported to user space via 
 **  the sysctl() binary interface.  Do *NOT* change the
 **  numbering of any existing values here, and do not change
 **  any numbers within any one set of values.  If you have to
 **  redefine an existing interface, use a new number for it.
 **  The kernel will then return -ENOTDIR to any application using
 **  the old binary interface.
 **
 ****************************************************************
 ****************************************************************
 */
#ifndef _LINUX_SYSCTL_H
#define _LINUX_SYSCTL_H

#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/wait.h>
#include <linux/rbtree.h>
#include <linux/uidgid.h>
#include <uapi/linux/sysctl.h>

/* For the /proc/sys support */
struct completion;
struct ctl_table;
struct nsproxy;
struct ctl_table_root;
struct ctl_table_header;
struct ctl_dir;

/* Keep the same order as in fs/proc/proc_sysctl.c */
#define SYSCTL_NEG_ONE			((void *)&sysctl_vals[0])
#define SYSCTL_ZERO			((void *)&sysctl_vals[1])
#define SYSCTL_ONE			((void *)&sysctl_vals[2])
#define SYSCTL_TWO			((void *)&sysctl_vals[3])
#define SYSCTL_FOUR			((void *)&sysctl_vals[4])
#define SYSCTL_ONE_HUNDRED		((void *)&sysctl_vals[5])
#define SYSCTL_TWO_HUNDRED		((void *)&sysctl_vals[6])
#define SYSCTL_ONE_THOUSAND		((void *)&sysctl_vals[7])
#define SYSCTL_THREE_THOUSAND		((void *)&sysctl_vals[8])
#define SYSCTL_INT_MAX			((void *)&sysctl_vals[9])

/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
#define SYSCTL_MAXOLDUID		((void *)&sysctl_vals[10])

extern const int sysctl_vals[];

#define SYSCTL_LONG_ZERO	((void *)&sysctl_long_vals[0])
#define SYSCTL_LONG_ONE		((void *)&sysctl_long_vals[1])
#define SYSCTL_LONG_MAX		((void *)&sysctl_long_vals[2])

extern const unsigned long sysctl_long_vals[];

typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer,
		size_t *lenp, loff_t *ppos);

int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_dobool(struct ctl_table *table, int write, void *buffer,
		size_t *lenp, loff_t *ppos);
int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer,
		size_t *lenp, loff_t *ppos);
int proc_dou8vec_minmax(struct ctl_table *table, int write, void *buffer,
			size_t *lenp, loff_t *ppos);
int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *,
		loff_t *);
int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *,
		loff_t *);
int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *,
		size_t *, loff_t *);
int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_do_static_key(struct ctl_table *table, int write, void *buffer,
		size_t *lenp, loff_t *ppos);

/*
 * Register a set of sysctl names by calling register_sysctl_table
 * with an initialised array of struct ctl_table's.  An entry with 
 * NULL procname terminates the table.  table->de will be
 * set up by the registration and need not be initialised in advance.
 *
 * sysctl names can be mirrored automatically under /proc/sys.  The
 * procname supplied controls /proc naming.
 *
 * The table's mode will be honoured for proc-fs access.
 *
 * Leaf nodes in the sysctl tree will be represented by a single file
 * under /proc; non-leaf nodes will be represented by directories.  A
 * null procname disables /proc mirroring at this node.
 *
 * The data and maxlen fields of the ctl_table
 * struct enable minimal validation of the values being written to be
 * performed, and the mode field allows minimal authentication.
 * 
 * There must be a proc_handler routine for any terminal nodes
 * mirrored under /proc/sys (non-terminals are handled by a built-in
 * directory handler).  Several default handlers are available to
 * cover common cases.
 */

/* Support for userspace poll() to watch for changes */
struct ctl_table_poll {
	atomic_t event;
	wait_queue_head_t wait;
};

static inline void *proc_sys_poll_event(struct ctl_table_poll *poll)
{
	return (void *)(unsigned long)atomic_read(&poll->event);
}

#define __CTL_TABLE_POLL_INITIALIZER(name) {				\
	.event = ATOMIC_INIT(0),					\
	.wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) }

#define DEFINE_CTL_TABLE_POLL(name)					\
	struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name)

/* A sysctl table is an array of struct ctl_table: */
struct ctl_table {
	const char *procname;		/* Text ID for /proc/sys, or zero */
	void *data;
	int maxlen;
	umode_t mode;
	struct ctl_table *child;	/* Deprecated */
	proc_handler *proc_handler;	/* Callback for text formatting */
	struct ctl_table_poll *poll;
	void *extra1;
	void *extra2;
} __randomize_layout;

struct ctl_node {
	struct rb_node node;
	struct ctl_table_header *header;
};

/* struct ctl_table_header is used to maintain dynamic lists of
   struct ctl_table trees. */
struct ctl_table_header {
	union {
		struct {
			struct ctl_table *ctl_table;
			int used;
			int count;
			int nreg;
		};
		struct rcu_head rcu;
	};
	struct completion *unregistering;
	struct ctl_table *ctl_table_arg;
	struct ctl_table_root *root;
	struct ctl_table_set *set;
	struct ctl_dir *parent;
	struct ctl_node *node;
	struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */
};

struct ctl_dir {
	/* Header must be at the start of ctl_dir */
	struct ctl_table_header header;
	struct rb_root root;
};

struct ctl_table_set {
	int (*is_seen)(struct ctl_table_set *);
	struct ctl_dir dir;
};

struct ctl_table_root {
	struct ctl_table_set default_set;
	struct ctl_table_set *(*lookup)(struct ctl_table_root *root);
	void (*set_ownership)(struct ctl_table_header *head,
			      struct ctl_table *table,
			      kuid_t *uid, kgid_t *gid);
	int (*permissions)(struct ctl_table_header *head, struct ctl_table *table);
};

/* struct ctl_path describes where in the hierarchy a table is added */
struct ctl_path {
	const char *procname;
};

#ifdef CONFIG_SYSCTL

#define DECLARE_SYSCTL_BASE(_name, _table)				\
static struct ctl_table _name##_base_table[] = {			\
	{								\
		.procname	= #_name,				\
		.mode		= 0555,					\
		.child		= _table,				\
	},								\
	{ },								\
}

extern int __register_sysctl_base(struct ctl_table *base_table);

#define register_sysctl_base(_name) __register_sysctl_base(_name##_base_table)

void proc_sys_poll_notify(struct ctl_table_poll *poll);

extern void setup_sysctl_set(struct ctl_table_set *p,
	struct ctl_table_root *root,
	int (*is_seen)(struct ctl_table_set *));
extern void retire_sysctl_set(struct ctl_table_set *set);

struct ctl_table_header *__register_sysctl_table(
	struct ctl_table_set *set,
	const char *path, struct ctl_table *table);
struct ctl_table_header *__register_sysctl_paths(
	struct ctl_table_set *set,
	const struct ctl_path *path, struct ctl_table *table);
struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table);
struct ctl_table_header *register_sysctl_table(struct ctl_table * table);
struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
						struct ctl_table *table);

void unregister_sysctl_table(struct ctl_table_header * table);

extern int sysctl_init_bases(void);
extern void __register_sysctl_init(const char *path, struct ctl_table *table,
				 const char *table_name);
#define register_sysctl_init(path, table) __register_sysctl_init(path, table, #table)
extern struct ctl_table_header *register_sysctl_mount_point(const char *path);

void do_sysctl_args(void);
int do_proc_douintvec(struct ctl_table *table, int write,
		      void *buffer, size_t *lenp, loff_t *ppos,
		      int (*conv)(unsigned long *lvalp,
				  unsigned int *valp,
				  int write, void *data),
		      void *data);

extern int pwrsw_enabled;
extern int unaligned_enabled;
extern int unaligned_dump_stack;
extern int no_unaligned_warning;

extern struct ctl_table sysctl_mount_point[];

#else /* CONFIG_SYSCTL */

#define DECLARE_SYSCTL_BASE(_name, _table)

static inline int __register_sysctl_base(struct ctl_table *base_table)
{
	return 0;
}

#define register_sysctl_base(table) __register_sysctl_base(table)

static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
{
	return NULL;
}

static inline struct sysctl_header *register_sysctl_mount_point(const char *path)
{
	return NULL;
}

static inline struct ctl_table_header *register_sysctl_paths(
			const struct ctl_path *path, struct ctl_table *table)
{
	return NULL;
}

static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table)
{
	return NULL;
}

static inline void unregister_sysctl_table(struct ctl_table_header * table)
{
}

static inline void setup_sysctl_set(struct ctl_table_set *p,
	struct ctl_table_root *root,
	int (*is_seen)(struct ctl_table_set *))
{
}

static inline void do_sysctl_args(void)
{
}
#endif /* CONFIG_SYSCTL */

int sysctl_max_threads(struct ctl_table *table, int write, void *buffer,
		size_t *lenp, loff_t *ppos);

#endif /* _LINUX_SYSCTL_H */