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_NEG_ONE ((void *)&android_gki_sysctl_vals[0])
42 #define SYSCTL_ZERO ((void *)&android_gki_sysctl_vals[1])
43 #define SYSCTL_ONE ((void *)&android_gki_sysctl_vals[2])
44 #define SYSCTL_TWO ((void *)&android_gki_sysctl_vals[3])
45 #define SYSCTL_FOUR ((void *)&android_gki_sysctl_vals[4])
46 #define SYSCTL_ONE_HUNDRED ((void *)&android_gki_sysctl_vals[5])
47 #define SYSCTL_TWO_HUNDRED ((void *)&android_gki_sysctl_vals[6])
48 #define SYSCTL_ONE_THOUSAND ((void *)&android_gki_sysctl_vals[7])
49 #define SYSCTL_THREE_THOUSAND ((void *)&android_gki_sysctl_vals[8])
50 #define SYSCTL_INT_MAX ((void *)&android_gki_sysctl_vals[9])
51
52 extern const int sysctl_vals[];
53 extern const int android_gki_sysctl_vals[];
54
55 typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer,
56 size_t *lenp, loff_t *ppos);
57
58 int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *);
59 int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *);
60 int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *);
61 int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
62 int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer,
63 size_t *lenp, loff_t *ppos);
64 int proc_dou8vec_minmax(struct ctl_table *table, int write, void *buffer,
65 size_t *lenp, loff_t *ppos);
66 int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *);
67 int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *,
68 loff_t *);
69 int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *,
70 loff_t *);
71 int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *);
72 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *,
73 size_t *, loff_t *);
74 int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *);
75 int proc_do_static_key(struct ctl_table *table, int write, void *buffer,
76 size_t *lenp, loff_t *ppos);
77
78 /*
79 * Register a set of sysctl names by calling register_sysctl_table
80 * with an initialised array of struct ctl_table's. An entry with
81 * NULL procname terminates the table. table->de will be
82 * set up by the registration and need not be initialised in advance.
83 *
84 * sysctl names can be mirrored automatically under /proc/sys. The
85 * procname supplied controls /proc naming.
86 *
87 * The table's mode will be honoured for proc-fs access.
88 *
89 * Leaf nodes in the sysctl tree will be represented by a single file
90 * under /proc; non-leaf nodes will be represented by directories. A
91 * null procname disables /proc mirroring at this node.
92 *
93 * The data and maxlen fields of the ctl_table
94 * struct enable minimal validation of the values being written to be
95 * performed, and the mode field allows minimal authentication.
96 *
97 * There must be a proc_handler routine for any terminal nodes
98 * mirrored under /proc/sys (non-terminals are handled by a built-in
99 * directory handler). Several default handlers are available to
100 * cover common cases.
101 */
102
103 /* Support for userspace poll() to watch for changes */
104 struct ctl_table_poll {
105 atomic_t event;
106 wait_queue_head_t wait;
107 };
108
proc_sys_poll_event(struct ctl_table_poll * poll)109 static inline void *proc_sys_poll_event(struct ctl_table_poll *poll)
110 {
111 return (void *)(unsigned long)atomic_read(&poll->event);
112 }
113
114 #define __CTL_TABLE_POLL_INITIALIZER(name) { \
115 .event = ATOMIC_INIT(0), \
116 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) }
117
118 #define DEFINE_CTL_TABLE_POLL(name) \
119 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name)
120
121 /* A sysctl table is an array of struct ctl_table: */
122 struct ctl_table {
123 const char *procname; /* Text ID for /proc/sys, or zero */
124 void *data;
125 int maxlen;
126 umode_t mode;
127 struct ctl_table *child; /* Deprecated */
128 proc_handler *proc_handler; /* Callback for text formatting */
129 struct ctl_table_poll *poll;
130 void *extra1;
131 void *extra2;
132 } __randomize_layout;
133
134 struct ctl_node {
135 struct rb_node node;
136 struct ctl_table_header *header;
137 };
138
139 /* struct ctl_table_header is used to maintain dynamic lists of
140 struct ctl_table trees. */
141 struct ctl_table_header {
142 union {
143 struct {
144 struct ctl_table *ctl_table;
145 int used;
146 int count;
147 int nreg;
148 };
149 struct rcu_head rcu;
150 };
151 struct completion *unregistering;
152 struct ctl_table *ctl_table_arg;
153 struct ctl_table_root *root;
154 struct ctl_table_set *set;
155 struct ctl_dir *parent;
156 struct ctl_node *node;
157 struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */
158 };
159
160 struct ctl_dir {
161 /* Header must be at the start of ctl_dir */
162 struct ctl_table_header header;
163 struct rb_root root;
164 };
165
166 struct ctl_table_set {
167 int (*is_seen)(struct ctl_table_set *);
168 struct ctl_dir dir;
169 };
170
171 struct ctl_table_root {
172 struct ctl_table_set default_set;
173 struct ctl_table_set *(*lookup)(struct ctl_table_root *root);
174 void (*set_ownership)(struct ctl_table_header *head,
175 struct ctl_table *table,
176 kuid_t *uid, kgid_t *gid);
177 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table);
178 };
179
180 /* struct ctl_path describes where in the hierarchy a table is added */
181 struct ctl_path {
182 const char *procname;
183 };
184
185 #ifdef CONFIG_SYSCTL
186
187 void proc_sys_poll_notify(struct ctl_table_poll *poll);
188
189 extern void setup_sysctl_set(struct ctl_table_set *p,
190 struct ctl_table_root *root,
191 int (*is_seen)(struct ctl_table_set *));
192 extern void retire_sysctl_set(struct ctl_table_set *set);
193
194 struct ctl_table_header *__register_sysctl_table(
195 struct ctl_table_set *set,
196 const char *path, struct ctl_table *table);
197 struct ctl_table_header *__register_sysctl_paths(
198 struct ctl_table_set *set,
199 const struct ctl_path *path, struct ctl_table *table);
200 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table);
201 struct ctl_table_header *register_sysctl_table(struct ctl_table * table);
202 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
203 struct ctl_table *table);
204
205 void unregister_sysctl_table(struct ctl_table_header * table);
206
207 extern int sysctl_init(void);
208 extern void __register_sysctl_init(const char *path, struct ctl_table *table,
209 const char *table_name);
210 #define register_sysctl_init(path, table) __register_sysctl_init(path, table, #table)
211 void do_sysctl_args(void);
212
213 extern int pwrsw_enabled;
214 extern int unaligned_enabled;
215 extern int unaligned_dump_stack;
216 extern int no_unaligned_warning;
217
218 extern struct ctl_table sysctl_mount_point[];
219 extern struct ctl_table random_table[];
220 extern struct ctl_table firmware_config_table[];
221 extern struct ctl_table epoll_table[];
222
223 #else /* CONFIG_SYSCTL */
register_sysctl_table(struct ctl_table * table)224 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
225 {
226 return NULL;
227 }
228
register_sysctl_paths(const struct ctl_path * path,struct ctl_table * table)229 static inline struct ctl_table_header *register_sysctl_paths(
230 const struct ctl_path *path, struct ctl_table *table)
231 {
232 return NULL;
233 }
234
register_sysctl(const char * path,struct ctl_table * table)235 static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table)
236 {
237 return NULL;
238 }
239
unregister_sysctl_table(struct ctl_table_header * table)240 static inline void unregister_sysctl_table(struct ctl_table_header * table)
241 {
242 }
243
setup_sysctl_set(struct ctl_table_set * p,struct ctl_table_root * root,int (* is_seen)(struct ctl_table_set *))244 static inline void setup_sysctl_set(struct ctl_table_set *p,
245 struct ctl_table_root *root,
246 int (*is_seen)(struct ctl_table_set *))
247 {
248 }
249
do_sysctl_args(void)250 static inline void do_sysctl_args(void)
251 {
252 }
253 #endif /* CONFIG_SYSCTL */
254
255 int sysctl_max_threads(struct ctl_table *table, int write, void *buffer,
256 size_t *lenp, loff_t *ppos);
257
258 #endif /* _LINUX_SYSCTL_H */
259