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