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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | /* |
3 | * sysctl.h: General linux system control interface | |
4 | * | |
5 | * Begun 24 March 1995, Stephen Tweedie | |
6 | * | |
7 | **************************************************************** | |
8 | **************************************************************** | |
9 | ** | |
7cc13edc | 10 | ** WARNING: |
1da177e4 | 11 | ** The values in this file are exported to user space via |
7cc13edc EB |
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 | |
93aec204 | 15 | ** redefine an existing interface, use a new number for it. |
7cc13edc EB |
16 | ** The kernel will then return -ENOTDIR to any application using |
17 | ** the old binary interface. | |
18 | ** | |
1da177e4 LT |
19 | **************************************************************** |
20 | **************************************************************** | |
21 | */ | |
1da177e4 LT |
22 | #ifndef _LINUX_SYSCTL_H |
23 | #define _LINUX_SYSCTL_H | |
24 | ||
d4ed803c | 25 | #include <linux/list.h> |
684adca4 | 26 | #include <linux/rcupdate.h> |
f1ecf068 | 27 | #include <linux/wait.h> |
ac13ac6f | 28 | #include <linux/rbtree.h> |
e79c6a4f | 29 | #include <linux/uidgid.h> |
607ca46e | 30 | #include <uapi/linux/sysctl.h> |
1da177e4 | 31 | |
805b5d5e | 32 | /* For the /proc/sys support */ |
db3f6001 | 33 | struct completion; |
1ff007eb | 34 | struct ctl_table; |
e51b6ba0 | 35 | struct nsproxy; |
d7321cd6 | 36 | struct ctl_table_root; |
f7e6ced4 | 37 | struct ctl_table_header; |
7ec66d06 | 38 | struct ctl_dir; |
f7e6ced4 | 39 | |
8d65af78 | 40 | typedef int proc_handler (struct ctl_table *ctl, int write, |
1da177e4 LT |
41 | void __user *buffer, size_t *lenp, loff_t *ppos); |
42 | ||
8d65af78 | 43 | extern int proc_dostring(struct ctl_table *, int, |
1da177e4 | 44 | void __user *, size_t *, loff_t *); |
8d65af78 | 45 | extern int proc_dointvec(struct ctl_table *, int, |
1da177e4 | 46 | void __user *, size_t *, loff_t *); |
e7d316a0 SAK |
47 | extern int proc_douintvec(struct ctl_table *, int, |
48 | void __user *, size_t *, loff_t *); | |
8d65af78 | 49 | extern int proc_dointvec_minmax(struct ctl_table *, int, |
1da177e4 | 50 | void __user *, size_t *, loff_t *); |
61d9b56a LR |
51 | extern int proc_douintvec_minmax(struct ctl_table *table, int write, |
52 | void __user *buffer, size_t *lenp, | |
53 | loff_t *ppos); | |
8d65af78 | 54 | extern int proc_dointvec_jiffies(struct ctl_table *, int, |
1da177e4 | 55 | void __user *, size_t *, loff_t *); |
8d65af78 | 56 | extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int, |
1da177e4 | 57 | void __user *, size_t *, loff_t *); |
8d65af78 | 58 | extern int proc_dointvec_ms_jiffies(struct ctl_table *, int, |
1da177e4 | 59 | void __user *, size_t *, loff_t *); |
8d65af78 | 60 | extern int proc_doulongvec_minmax(struct ctl_table *, int, |
1da177e4 | 61 | void __user *, size_t *, loff_t *); |
d8217f07 | 62 | extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, |
8d65af78 | 63 | void __user *, size_t *, loff_t *); |
9f977fb7 OP |
64 | extern int proc_do_large_bitmap(struct ctl_table *, int, |
65 | void __user *, size_t *, loff_t *); | |
1da177e4 | 66 | |
1da177e4 LT |
67 | /* |
68 | * Register a set of sysctl names by calling register_sysctl_table | |
2315ffa0 EB |
69 | * with an initialised array of struct ctl_table's. An entry with |
70 | * NULL procname terminates the table. table->de will be | |
d99f160a | 71 | * set up by the registration and need not be initialised in advance. |
1da177e4 LT |
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. | |
d99f160a | 82 | * |
1da177e4 LT |
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 | * | |
1da177e4 LT |
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 | ||
f1ecf068 LDM |
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 | ||
f1ecf068 LDM |
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 | ||
1da177e4 LT |
112 | /* A sysctl table is an array of struct ctl_table: */ |
113 | struct ctl_table | |
114 | { | |
1da177e4 LT |
115 | const char *procname; /* Text ID for /proc/sys, or zero */ |
116 | void *data; | |
117 | int maxlen; | |
36fcb589 | 118 | umode_t mode; |
f728019b | 119 | struct ctl_table *child; /* Deprecated */ |
1da177e4 | 120 | proc_handler *proc_handler; /* Callback for text formatting */ |
f1ecf068 | 121 | struct ctl_table_poll *poll; |
1da177e4 LT |
122 | void *extra1; |
123 | void *extra2; | |
3859a271 | 124 | } __randomize_layout; |
1da177e4 | 125 | |
ac13ac6f EB |
126 | struct ctl_node { |
127 | struct rb_node node; | |
128 | struct ctl_table_header *header; | |
129 | }; | |
130 | ||
1da177e4 | 131 | /* struct ctl_table_header is used to maintain dynamic lists of |
d8217f07 | 132 | struct ctl_table trees. */ |
1da177e4 LT |
133 | struct ctl_table_header |
134 | { | |
dfef6dcd AV |
135 | union { |
136 | struct { | |
137 | struct ctl_table *ctl_table; | |
dfef6dcd AV |
138 | int used; |
139 | int count; | |
938aaa4f | 140 | int nreg; |
dfef6dcd AV |
141 | }; |
142 | struct rcu_head rcu; | |
143 | }; | |
330d57fb | 144 | struct completion *unregistering; |
23eb06de | 145 | struct ctl_table *ctl_table_arg; |
e51b6ba0 | 146 | struct ctl_table_root *root; |
73455092 | 147 | struct ctl_table_set *set; |
7ec66d06 | 148 | struct ctl_dir *parent; |
ac13ac6f | 149 | struct ctl_node *node; |
2fd1d2c4 | 150 | struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */ |
7ec66d06 EB |
151 | }; |
152 | ||
153 | struct ctl_dir { | |
154 | /* Header must be at the start of ctl_dir */ | |
155 | struct ctl_table_header header; | |
ac13ac6f | 156 | struct rb_root root; |
1da177e4 LT |
157 | }; |
158 | ||
0ce8974d | 159 | struct ctl_table_set { |
0ce8974d | 160 | int (*is_seen)(struct ctl_table_set *); |
0e47c99d | 161 | struct ctl_dir dir; |
0ce8974d EB |
162 | }; |
163 | ||
164 | struct ctl_table_root { | |
0ce8974d | 165 | struct ctl_table_set default_set; |
13bcc6a2 | 166 | struct ctl_table_set *(*lookup)(struct ctl_table_root *root); |
e79c6a4f DT |
167 | void (*set_ownership)(struct ctl_table_header *head, |
168 | struct ctl_table *table, | |
169 | kuid_t *uid, kgid_t *gid); | |
73f7ef43 | 170 | int (*permissions)(struct ctl_table_header *head, struct ctl_table *table); |
0ce8974d EB |
171 | }; |
172 | ||
29e796fd EB |
173 | /* struct ctl_path describes where in the hierarchy a table is added */ |
174 | struct ctl_path { | |
175 | const char *procname; | |
29e796fd EB |
176 | }; |
177 | ||
0ce8974d EB |
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, | |
9eb47c26 | 183 | struct ctl_table_root *root, |
0ce8974d | 184 | int (*is_seen)(struct ctl_table_set *)); |
97324cd8 | 185 | extern void retire_sysctl_set(struct ctl_table_set *set); |
0ce8974d | 186 | |
6e9d5164 | 187 | struct ctl_table_header *__register_sysctl_table( |
60a47a2e | 188 | struct ctl_table_set *set, |
6e9d5164 | 189 | const char *path, struct ctl_table *table); |
e51b6ba0 | 190 | struct ctl_table_header *__register_sysctl_paths( |
60a47a2e | 191 | struct ctl_table_set *set, |
e51b6ba0 | 192 | const struct ctl_path *path, struct ctl_table *table); |
fea478d4 | 193 | struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table); |
d8217f07 | 194 | struct ctl_table_header *register_sysctl_table(struct ctl_table * table); |
29e796fd EB |
195 | struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, |
196 | struct ctl_table *table); | |
0b4d4147 | 197 | |
1da177e4 LT |
198 | void unregister_sysctl_table(struct ctl_table_header * table); |
199 | ||
de4e83bd | 200 | extern int sysctl_init(void); |
f9bd6733 EB |
201 | |
202 | extern struct ctl_table sysctl_mount_point[]; | |
203 | ||
0ce8974d EB |
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 | ||
e609a6b8 AB |
216 | static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) |
217 | { | |
218 | return NULL; | |
219 | } | |
220 | ||
0ce8974d EB |
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, | |
9eb47c26 | 226 | struct ctl_table_root *root, |
0ce8974d EB |
227 | int (*is_seen)(struct ctl_table_set *)) |
228 | { | |
229 | } | |
230 | ||
0ce8974d EB |
231 | #endif /* CONFIG_SYSCTL */ |
232 | ||
16db3d3f HS |
233 | int sysctl_max_threads(struct ctl_table *table, int write, |
234 | void __user *buffer, size_t *lenp, loff_t *ppos); | |
235 | ||
1da177e4 | 236 | #endif /* _LINUX_SYSCTL_H */ |