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