Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
sysctl.h
Go to the documentation of this file.
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 */
31 struct ctl_table;
32 struct nsproxy;
33 struct ctl_table_root;
34 struct ctl_table_header;
35 struct ctl_dir;
36 
37 typedef struct ctl_table ctl_table;
38 
39 typedef int proc_handler (struct ctl_table *ctl, int write,
40  void __user *buffer, size_t *lenp, loff_t *ppos);
41 
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_dointvec_minmax(struct ctl_table *, int,
47  void __user *, size_t *, loff_t *);
48 extern int proc_dointvec_jiffies(struct ctl_table *, int,
49  void __user *, size_t *, loff_t *);
50 extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int,
51  void __user *, size_t *, loff_t *);
52 extern int proc_dointvec_ms_jiffies(struct ctl_table *, int,
53  void __user *, size_t *, loff_t *);
54 extern int proc_doulongvec_minmax(struct ctl_table *, int,
55  void __user *, size_t *, loff_t *);
56 extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int,
57  void __user *, size_t *, loff_t *);
58 extern 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 */
89 struct ctl_table_poll {
90  atomic_t event;
91  wait_queue_head_t wait;
92 };
93 
94 static 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: */
107 struct 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 
120 struct 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. */
127 struct 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 
146 struct 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 
152 struct ctl_table_set {
153  int (*is_seen)(struct ctl_table_set *);
154  struct ctl_dir dir;
155 };
156 
157 struct 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_root *root,
162  struct nsproxy *namespaces, struct ctl_table *table);
163 };
164 
165 /* struct ctl_path describes where in the hierarchy a table is added */
166 struct ctl_path {
167  const char *procname;
168 };
169 
170 #ifdef CONFIG_SYSCTL
171 
172 void proc_sys_poll_notify(struct ctl_table_poll *poll);
173 
174 extern void setup_sysctl_set(struct ctl_table_set *p,
175  struct ctl_table_root *root,
176  int (*is_seen)(struct ctl_table_set *));
177 extern void retire_sysctl_set(struct ctl_table_set *set);
178 
179 void register_sysctl_root(struct ctl_table_root *root);
180 struct ctl_table_header *__register_sysctl_table(
181  struct ctl_table_set *set,
182  const char *path, struct ctl_table *table);
183 struct ctl_table_header *__register_sysctl_paths(
184  struct ctl_table_set *set,
185  const struct ctl_path *path, struct ctl_table *table);
186 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table);
187 struct ctl_table_header *register_sysctl_table(struct ctl_table * table);
188 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
189  struct ctl_table *table);
190 
191 void unregister_sysctl_table(struct ctl_table_header * table);
192 
193 extern int sysctl_init(void);
194 #else /* CONFIG_SYSCTL */
195 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
196 {
197  return NULL;
198 }
199 
200 static inline struct ctl_table_header *register_sysctl_paths(
201  const struct ctl_path *path, struct ctl_table *table)
202 {
203  return NULL;
204 }
205 
206 static inline void unregister_sysctl_table(struct ctl_table_header * table)
207 {
208 }
209 
210 static inline void setup_sysctl_set(struct ctl_table_set *p,
211  struct ctl_table_root *root,
212  int (*is_seen)(struct ctl_table_set *))
213 {
214 }
215 
216 #endif /* CONFIG_SYSCTL */
217 
218 #endif /* _LINUX_SYSCTL_H */
Generated on Thu Jan 10 2013 14:49:19 for Linux Kernel by   doxygen 1.8.2