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 completion; 32 struct ctl_table; 33 struct nsproxy; 34 struct ctl_table_root; 35 struct ctl_table_header; 36 struct ctl_dir; 37 38 typedef int proc_handler (struct ctl_table *ctl, int write, 39 void __user *buffer, size_t *lenp, loff_t *ppos); 40 41 extern int proc_dostring(struct ctl_table *, int, 42 void __user *, size_t *, loff_t *); 43 extern int proc_dointvec(struct ctl_table *, int, 44 void __user *, size_t *, loff_t *); 45 extern int proc_douintvec(struct ctl_table *, int, 46 void __user *, size_t *, loff_t *); 47 extern int proc_dointvec_minmax(struct ctl_table *, int, 48 void __user *, size_t *, loff_t *); 49 extern int proc_dointvec_jiffies(struct ctl_table *, int, 50 void __user *, size_t *, loff_t *); 51 extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int, 52 void __user *, size_t *, loff_t *); 53 extern int proc_dointvec_ms_jiffies(struct ctl_table *, int, 54 void __user *, size_t *, loff_t *); 55 extern int proc_doulongvec_minmax(struct ctl_table *, int, 56 void __user *, size_t *, loff_t *); 57 extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, 58 void __user *, size_t *, loff_t *); 59 extern int proc_do_large_bitmap(struct ctl_table *, int, 60 void __user *, size_t *, loff_t *); 61 62 /* 63 * Register a set of sysctl names by calling register_sysctl_table 64 * with an initialised array of struct ctl_table's. An entry with 65 * NULL procname terminates the table. table->de will be 66 * set up by the registration and need not be initialised in advance. 67 * 68 * sysctl names can be mirrored automatically under /proc/sys. The 69 * procname supplied controls /proc naming. 70 * 71 * The table's mode will be honoured both for sys_sysctl(2) and 72 * proc-fs access. 73 * 74 * Leaf nodes in the sysctl tree will be represented by a single file 75 * under /proc; non-leaf nodes will be represented by directories. A 76 * null procname disables /proc mirroring at this node. 77 * 78 * sysctl(2) can automatically manage read and write requests through 79 * the sysctl table. The data and maxlen fields of the ctl_table 80 * struct enable minimal validation of the values being written to be 81 * performed, and the mode field allows minimal authentication. 82 * 83 * There must be a proc_handler routine for any terminal nodes 84 * mirrored under /proc/sys (non-terminals are handled by a built-in 85 * directory handler). Several default handlers are available to 86 * cover common cases. 87 */ 88 89 /* Support for userspace poll() to watch for changes */ 90 struct ctl_table_poll { 91 atomic_t event; 92 wait_queue_head_t wait; 93 }; 94 95 static inline void *proc_sys_poll_event(struct ctl_table_poll *poll) 96 { 97 return (void *)(unsigned long)atomic_read(&poll->event); 98 } 99 100 #define __CTL_TABLE_POLL_INITIALIZER(name) { \ 101 .event = ATOMIC_INIT(0), \ 102 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) } 103 104 #define DEFINE_CTL_TABLE_POLL(name) \ 105 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name) 106 107 /* A sysctl table is an array of struct ctl_table: */ 108 struct ctl_table 109 { 110 const char *procname; /* Text ID for /proc/sys, or zero */ 111 void *data; 112 int maxlen; 113 umode_t mode; 114 struct ctl_table *child; /* Deprecated */ 115 proc_handler *proc_handler; /* Callback for text formatting */ 116 struct ctl_table_poll *poll; 117 void *extra1; 118 void *extra2; 119 }; 120 121 struct ctl_node { 122 struct rb_node node; 123 struct ctl_table_header *header; 124 }; 125 126 /* struct ctl_table_header is used to maintain dynamic lists of 127 struct ctl_table trees. */ 128 struct ctl_table_header 129 { 130 union { 131 struct { 132 struct ctl_table *ctl_table; 133 int used; 134 int count; 135 int nreg; 136 }; 137 struct rcu_head rcu; 138 }; 139 struct completion *unregistering; 140 struct ctl_table *ctl_table_arg; 141 struct ctl_table_root *root; 142 struct ctl_table_set *set; 143 struct ctl_dir *parent; 144 struct ctl_node *node; 145 }; 146 147 struct ctl_dir { 148 /* Header must be at the start of ctl_dir */ 149 struct ctl_table_header header; 150 struct rb_root root; 151 }; 152 153 struct ctl_table_set { 154 int (*is_seen)(struct ctl_table_set *); 155 struct ctl_dir dir; 156 }; 157 158 struct ctl_table_root { 159 struct ctl_table_set default_set; 160 struct ctl_table_set *(*lookup)(struct ctl_table_root *root, 161 struct nsproxy *namespaces); 162 int (*permissions)(struct ctl_table_header *head, 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); 194 195 extern struct ctl_table sysctl_mount_point[]; 196 197 #else /* CONFIG_SYSCTL */ 198 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table) 199 { 200 return NULL; 201 } 202 203 static inline struct ctl_table_header *register_sysctl_paths( 204 const struct ctl_path *path, struct ctl_table *table) 205 { 206 return NULL; 207 } 208 209 static inline void unregister_sysctl_table(struct ctl_table_header * table) 210 { 211 } 212 213 static inline void setup_sysctl_set(struct ctl_table_set *p, 214 struct ctl_table_root *root, 215 int (*is_seen)(struct ctl_table_set *)) 216 { 217 } 218 219 #endif /* CONFIG_SYSCTL */ 220 221 int sysctl_max_threads(struct ctl_table *table, int write, 222 void __user *buffer, size_t *lenp, loff_t *ppos); 223 224 #endif /* _LINUX_SYSCTL_H */ 225