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_header *head, struct ctl_table *table); 162 }; 163 164 /* struct ctl_path describes where in the hierarchy a table is added */ 165 struct ctl_path { 166 const char *procname; 167 }; 168 169 #ifdef CONFIG_SYSCTL 170 171 void proc_sys_poll_notify(struct ctl_table_poll *poll); 172 173 extern void setup_sysctl_set(struct ctl_table_set *p, 174 struct ctl_table_root *root, 175 int (*is_seen)(struct ctl_table_set *)); 176 extern void retire_sysctl_set(struct ctl_table_set *set); 177 178 void register_sysctl_root(struct ctl_table_root *root); 179 struct ctl_table_header *__register_sysctl_table( 180 struct ctl_table_set *set, 181 const char *path, struct ctl_table *table); 182 struct ctl_table_header *__register_sysctl_paths( 183 struct ctl_table_set *set, 184 const struct ctl_path *path, struct ctl_table *table); 185 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table); 186 struct ctl_table_header *register_sysctl_table(struct ctl_table * table); 187 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 188 struct ctl_table *table); 189 190 void unregister_sysctl_table(struct ctl_table_header * table); 191 192 extern int sysctl_init(void); 193 #else /* CONFIG_SYSCTL */ 194 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table) 195 { 196 return NULL; 197 } 198 199 static inline struct ctl_table_header *register_sysctl_paths( 200 const struct ctl_path *path, struct ctl_table *table) 201 { 202 return NULL; 203 } 204 205 static inline void unregister_sysctl_table(struct ctl_table_header * table) 206 { 207 } 208 209 static 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 */ 218