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