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 <linux/uidgid.h> 29 #include <uapi/linux/sysctl.h> 30 31 /* For the /proc/sys support */ 32 struct completion; 33 struct ctl_table; 34 struct nsproxy; 35 struct ctl_table_root; 36 struct ctl_table_header; 37 struct ctl_dir; 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_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 *); 62 63 /* 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. 68 * 69 * sysctl names can be mirrored automatically under /proc/sys. The 70 * procname supplied controls /proc naming. 71 * 72 * The table's mode will be honoured both for sys_sysctl(2) and 73 * proc-fs access. 74 * 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. 78 * 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. 83 * 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 87 * cover common cases. 88 */ 89 90 /* Support for userspace poll() to watch for changes */ 91 struct ctl_table_poll { 92 atomic_t event; 93 wait_queue_head_t wait; 94 }; 95 96 static inline void *proc_sys_poll_event(struct ctl_table_poll *poll) 97 { 98 return (void *)(unsigned long)atomic_read(&poll->event); 99 } 100 101 #define __CTL_TABLE_POLL_INITIALIZER(name) { \ 102 .event = ATOMIC_INIT(0), \ 103 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) } 104 105 #define DEFINE_CTL_TABLE_POLL(name) \ 106 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name) 107 108 /* A sysctl table is an array of struct ctl_table: */ 109 struct ctl_table 110 { 111 const char *procname; /* Text ID for /proc/sys, or zero */ 112 void *data; 113 int maxlen; 114 umode_t mode; 115 struct ctl_table *child; /* Deprecated */ 116 proc_handler *proc_handler; /* Callback for text formatting */ 117 struct ctl_table_poll *poll; 118 void *extra1; 119 void *extra2; 120 }; 121 122 struct ctl_node { 123 struct rb_node node; 124 struct ctl_table_header *header; 125 }; 126 127 /* struct ctl_table_header is used to maintain dynamic lists of 128 struct ctl_table trees. */ 129 struct ctl_table_header 130 { 131 union { 132 struct { 133 struct ctl_table *ctl_table; 134 int used; 135 int count; 136 int nreg; 137 }; 138 struct rcu_head rcu; 139 }; 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; 146 struct list_head inodes; /* head for proc_inode->sysctl_inodes */ 147 }; 148 149 struct ctl_dir { 150 /* Header must be at the start of ctl_dir */ 151 struct ctl_table_header header; 152 struct rb_root root; 153 }; 154 155 struct ctl_table_set { 156 int (*is_seen)(struct ctl_table_set *); 157 struct ctl_dir dir; 158 }; 159 160 struct ctl_table_root { 161 struct ctl_table_set default_set; 162 struct ctl_table_set *(*lookup)(struct ctl_table_root *root); 163 void (*set_ownership)(struct ctl_table_header *head, 164 struct ctl_table *table, 165 kuid_t *uid, kgid_t *gid); 166 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table); 167 }; 168 169 /* struct ctl_path describes where in the hierarchy a table is added */ 170 struct ctl_path { 171 const char *procname; 172 }; 173 174 #ifdef CONFIG_SYSCTL 175 176 void proc_sys_poll_notify(struct ctl_table_poll *poll); 177 178 extern void setup_sysctl_set(struct ctl_table_set *p, 179 struct ctl_table_root *root, 180 int (*is_seen)(struct ctl_table_set *)); 181 extern void retire_sysctl_set(struct ctl_table_set *set); 182 183 void register_sysctl_root(struct ctl_table_root *root); 184 struct ctl_table_header *__register_sysctl_table( 185 struct ctl_table_set *set, 186 const char *path, struct ctl_table *table); 187 struct ctl_table_header *__register_sysctl_paths( 188 struct ctl_table_set *set, 189 const struct ctl_path *path, struct ctl_table *table); 190 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table); 191 struct ctl_table_header *register_sysctl_table(struct ctl_table * table); 192 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 193 struct ctl_table *table); 194 195 void unregister_sysctl_table(struct ctl_table_header * table); 196 197 extern int sysctl_init(void); 198 199 extern struct ctl_table sysctl_mount_point[]; 200 201 #else /* CONFIG_SYSCTL */ 202 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table) 203 { 204 return NULL; 205 } 206 207 static inline struct ctl_table_header *register_sysctl_paths( 208 const struct ctl_path *path, struct ctl_table *table) 209 { 210 return NULL; 211 } 212 213 static inline void unregister_sysctl_table(struct ctl_table_header * table) 214 { 215 } 216 217 static inline void setup_sysctl_set(struct ctl_table_set *p, 218 struct ctl_table_root *root, 219 int (*is_seen)(struct ctl_table_set *)) 220 { 221 } 222 223 #endif /* CONFIG_SYSCTL */ 224 225 int sysctl_max_threads(struct ctl_table *table, int write, 226 void __user *buffer, size_t *lenp, loff_t *ppos); 227 228 #endif /* _LINUX_SYSCTL_H */ 229