projects/linux·blob v3.8-rc2 · refs

217 lines · 6.6 KiB

1/*
2 * sysctl.h: General linux system control interface
3 *
4 * Begun 24 March 1995, Stephen Tweedie
5 *
6 ****************************************************************
7 ****************************************************************
8 **
9 ** WARNING:
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.
17 **
18 ****************************************************************
19 ****************************************************************
20 */
21#ifndef _LINUX_SYSCTL_H
22#define _LINUX_SYSCTL_H
23
24#include <linux/list.h>
25#include <linux/rcupdate.h>
26#include <linux/wait.h>
27#include <linux/rbtree.h>
28#include <uapi/linux/sysctl.h>
29
30/* For the /proc/sys support */
31struct ctl_table;
32struct nsproxy;
33struct ctl_table_root;
34struct ctl_table_header;
35struct ctl_dir;
36
37typedef struct ctl_table ctl_table;
38
39typedef int proc_handler (struct ctl_table *ctl, int write,
40 void __user *buffer, size_t *lenp, loff_t *ppos);
41
42extern int proc_dostring(struct ctl_table *, int,
43 void __user *, size_t *, loff_t *);
44extern int proc_dointvec(struct ctl_table *, int,
45 void __user *, size_t *, loff_t *);
46extern int proc_dointvec_minmax(struct ctl_table *, int,
47 void __user *, size_t *, loff_t *);
48extern int proc_dointvec_jiffies(struct ctl_table *, int,
49 void __user *, size_t *, loff_t *);
50extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int,
51 void __user *, size_t *, loff_t *);
52extern int proc_dointvec_ms_jiffies(struct ctl_table *, int,
53 void __user *, size_t *, loff_t *);
54extern int proc_doulongvec_minmax(struct ctl_table *, int,
55 void __user *, size_t *, loff_t *);
56extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int,
57 void __user *, size_t *, loff_t *);
58extern int proc_do_large_bitmap(struct ctl_table *, int,
59 void __user *, size_t *, loff_t *);
60
61/*
62 * Register a set of sysctl names by calling register_sysctl_table
63 * with an initialised array of struct ctl_table's. An entry with
64 * NULL procname terminates the table. table->de will be
65 * set up by the registration and need not be initialised in advance.
66 *
67 * sysctl names can be mirrored automatically under /proc/sys. The
68 * procname supplied controls /proc naming.
69 *
70 * The table's mode will be honoured both for sys_sysctl(2) and
71 * proc-fs access.
72 *
73 * Leaf nodes in the sysctl tree will be represented by a single file
74 * under /proc; non-leaf nodes will be represented by directories. A
75 * null procname disables /proc mirroring at this node.
76 *
77 * sysctl(2) can automatically manage read and write requests through
78 * the sysctl table. The data and maxlen fields of the ctl_table
79 * struct enable minimal validation of the values being written to be
80 * performed, and the mode field allows minimal authentication.
81 *
82 * There must be a proc_handler routine for any terminal nodes
83 * mirrored under /proc/sys (non-terminals are handled by a built-in
84 * directory handler). Several default handlers are available to
85 * cover common cases.
86 */
87
88/* Support for userspace poll() to watch for changes */
89struct ctl_table_poll {
90 atomic_t event;
91 wait_queue_head_t wait;
92};
93
94static inline void *proc_sys_poll_event(struct ctl_table_poll *poll)
95{
96 return (void *)(unsigned long)atomic_read(&poll->event);
97}
98
99#define __CTL_TABLE_POLL_INITIALIZER(name) { \
100 .event = ATOMIC_INIT(0), \
101 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) }
102
103#define DEFINE_CTL_TABLE_POLL(name) \
104 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name)
105
106/* A sysctl table is an array of struct ctl_table: */
107struct ctl_table
108{
109 const char *procname; /* Text ID for /proc/sys, or zero */
110 void *data;
111 int maxlen;
112 umode_t mode;
113 struct ctl_table *child; /* Deprecated */
114 proc_handler *proc_handler; /* Callback for text formatting */
115 struct ctl_table_poll *poll;
116 void *extra1;
117 void *extra2;
118};
119
120struct ctl_node {
121 struct rb_node node;
122 struct ctl_table_header *header;
123};
124
125/* struct ctl_table_header is used to maintain dynamic lists of
126 struct ctl_table trees. */
127struct ctl_table_header
128{
129 union {
130 struct {
131 struct ctl_table *ctl_table;
132 int used;
133 int count;
134 int nreg;
135 };
136 struct rcu_head rcu;
137 };
138 struct completion *unregistering;
139 struct ctl_table *ctl_table_arg;
140 struct ctl_table_root *root;
141 struct ctl_table_set *set;
142 struct ctl_dir *parent;
143 struct ctl_node *node;
144};
145
146struct ctl_dir {
147 /* Header must be at the start of ctl_dir */
148 struct ctl_table_header header;
149 struct rb_root root;
150};
151
152struct ctl_table_set {
153 int (*is_seen)(struct ctl_table_set *);
154 struct ctl_dir dir;
155};
156
157struct ctl_table_root {
158 struct ctl_table_set default_set;
159 struct ctl_table_set *(*lookup)(struct ctl_table_root *root,
160 struct nsproxy *namespaces);
161 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table);
162};
163
164/* struct ctl_path describes where in the hierarchy a table is added */
165struct ctl_path {
166 const char *procname;
167};
168
169#ifdef CONFIG_SYSCTL
170
171void proc_sys_poll_notify(struct ctl_table_poll *poll);
172
173extern void setup_sysctl_set(struct ctl_table_set *p,
174 struct ctl_table_root *root,
175 int (*is_seen)(struct ctl_table_set *));
176extern void retire_sysctl_set(struct ctl_table_set *set);
177
178void register_sysctl_root(struct ctl_table_root *root);
179struct ctl_table_header *__register_sysctl_table(
180 struct ctl_table_set *set,
181 const char *path, struct ctl_table *table);
182struct ctl_table_header *__register_sysctl_paths(
183 struct ctl_table_set *set,
184 const struct ctl_path *path, struct ctl_table *table);
185struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table);
186struct ctl_table_header *register_sysctl_table(struct ctl_table * table);
187struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
188 struct ctl_table *table);
189
190void unregister_sysctl_table(struct ctl_table_header * table);
191
192extern int sysctl_init(void);
193#else /* CONFIG_SYSCTL */
194static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
195{
196 return NULL;
197}
198
199static inline struct ctl_table_header *register_sysctl_paths(
200 const struct ctl_path *path, struct ctl_table *table)
201{
202 return NULL;
203}
204
205static inline void unregister_sysctl_table(struct ctl_table_header * table)
206{
207}
208
209static inline void setup_sysctl_set(struct ctl_table_set *p,
210 struct ctl_table_root *root,
211 int (*is_seen)(struct ctl_table_set *))
212{
213}
214
215#endif /* CONFIG_SYSCTL */
216
217#endif /* _LINUX_SYSCTL_H */