2 * sysctl.h: General linux system control interface
4 * Begun 24 March 1995, Stephen Tweedie
6 ****************************************************************
7 ****************************************************************
10 ** The values in this file are exported to user space via
11 ** the sysctl() binary interface. Do *NOT* change the
12 ** numbering of any existing values here, and do not change
13 ** any numbers within any one set of values. If you have to
14 ** redefine an existing interface, use a new number for it.
15 ** The kernel will then return -ENOTDIR to any application using
16 ** the old binary interface.
18 ****************************************************************
19 ****************************************************************
21 #ifndef _LINUX_SYSCTL_H
22 #define _LINUX_SYSCTL_H
24 #include <linux/list.h>
25 #include <linux/rcupdate.h>
26 #include <linux/wait.h>
27 #include <linux/rbtree.h>
28 #include <linux/uidgid.h>
29 #include <uapi/linux/sysctl.h>
31 /* For the /proc/sys support */
35 struct ctl_table_root;
36 struct ctl_table_header;
39 typedef int proc_handler (struct ctl_table *ctl, int write,
40 void __user *buffer, size_t *lenp, loff_t *ppos);
42 extern int proc_dostring(struct ctl_table *, int,
43 void __user *, size_t *, loff_t *);
44 extern int proc_dointvec(struct ctl_table *, int,
45 void __user *, size_t *, loff_t *);
46 extern int proc_douintvec(struct ctl_table *, int,
47 void __user *, size_t *, loff_t *);
48 extern int proc_dointvec_minmax(struct ctl_table *, int,
49 void __user *, size_t *, loff_t *);
50 extern int proc_dointvec_jiffies(struct ctl_table *, int,
51 void __user *, size_t *, loff_t *);
52 extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int,
53 void __user *, size_t *, loff_t *);
54 extern int proc_dointvec_ms_jiffies(struct ctl_table *, int,
55 void __user *, size_t *, loff_t *);
56 extern int proc_doulongvec_minmax(struct ctl_table *, int,
57 void __user *, size_t *, loff_t *);
58 extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int,
59 void __user *, size_t *, loff_t *);
60 extern int proc_do_large_bitmap(struct ctl_table *, int,
61 void __user *, size_t *, loff_t *);
64 * Register a set of sysctl names by calling register_sysctl_table
65 * with an initialised array of struct ctl_table's. An entry with
66 * NULL procname terminates the table. table->de will be
67 * set up by the registration and need not be initialised in advance.
69 * sysctl names can be mirrored automatically under /proc/sys. The
70 * procname supplied controls /proc naming.
72 * The table's mode will be honoured both for sys_sysctl(2) and
75 * Leaf nodes in the sysctl tree will be represented by a single file
76 * under /proc; non-leaf nodes will be represented by directories. A
77 * null procname disables /proc mirroring at this node.
79 * sysctl(2) can automatically manage read and write requests through
80 * the sysctl table. The data and maxlen fields of the ctl_table
81 * struct enable minimal validation of the values being written to be
82 * performed, and the mode field allows minimal authentication.
84 * There must be a proc_handler routine for any terminal nodes
85 * mirrored under /proc/sys (non-terminals are handled by a built-in
86 * directory handler). Several default handlers are available to
90 /* Support for userspace poll() to watch for changes */
91 struct ctl_table_poll {
93 wait_queue_head_t wait;
96 static inline void *proc_sys_poll_event(struct ctl_table_poll *poll)
98 return (void *)(unsigned long)atomic_read(&poll->event);
101 #define __CTL_TABLE_POLL_INITIALIZER(name) { \
102 .event = ATOMIC_INIT(0), \
103 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) }
105 #define DEFINE_CTL_TABLE_POLL(name) \
106 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name)
108 /* A sysctl table is an array of struct ctl_table: */
111 const char *procname; /* Text ID for /proc/sys, or zero */
115 struct ctl_table *child; /* Deprecated */
116 proc_handler *proc_handler; /* Callback for text formatting */
117 struct ctl_table_poll *poll;
124 struct ctl_table_header *header;
127 /* struct ctl_table_header is used to maintain dynamic lists of
128 struct ctl_table trees. */
129 struct ctl_table_header
133 struct ctl_table *ctl_table;
140 struct completion *unregistering;
141 struct ctl_table *ctl_table_arg;
142 struct ctl_table_root *root;
143 struct ctl_table_set *set;
144 struct ctl_dir *parent;
145 struct ctl_node *node;
149 /* Header must be at the start of ctl_dir */
150 struct ctl_table_header header;
154 struct ctl_table_set {
155 int (*is_seen)(struct ctl_table_set *);
159 struct ctl_table_root {
160 struct ctl_table_set default_set;
161 struct ctl_table_set *(*lookup)(struct ctl_table_root *root);
162 void (*set_ownership)(struct ctl_table_header *head,
163 struct ctl_table *table,
164 kuid_t *uid, kgid_t *gid);
165 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table);
168 /* struct ctl_path describes where in the hierarchy a table is added */
170 const char *procname;
175 void proc_sys_poll_notify(struct ctl_table_poll *poll);
177 extern void setup_sysctl_set(struct ctl_table_set *p,
178 struct ctl_table_root *root,
179 int (*is_seen)(struct ctl_table_set *));
180 extern void retire_sysctl_set(struct ctl_table_set *set);
182 void register_sysctl_root(struct ctl_table_root *root);
183 struct ctl_table_header *__register_sysctl_table(
184 struct ctl_table_set *set,
185 const char *path, struct ctl_table *table);
186 struct ctl_table_header *__register_sysctl_paths(
187 struct ctl_table_set *set,
188 const struct ctl_path *path, struct ctl_table *table);
189 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table);
190 struct ctl_table_header *register_sysctl_table(struct ctl_table * table);
191 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
192 struct ctl_table *table);
194 void unregister_sysctl_table(struct ctl_table_header * table);
196 extern int sysctl_init(void);
198 extern struct ctl_table sysctl_mount_point[];
200 #else /* CONFIG_SYSCTL */
201 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
206 static inline struct ctl_table_header *register_sysctl_paths(
207 const struct ctl_path *path, struct ctl_table *table)
212 static inline void unregister_sysctl_table(struct ctl_table_header * table)
216 static inline void setup_sysctl_set(struct ctl_table_set *p,
217 struct ctl_table_root *root,
218 int (*is_seen)(struct ctl_table_set *))
222 #endif /* CONFIG_SYSCTL */
224 int sysctl_max_threads(struct ctl_table *table, int write,
225 void __user *buffer, size_t *lenp, loff_t *ppos);
227 #endif /* _LINUX_SYSCTL_H */