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_douintvec_minmax(struct ctl_table *table, int write, 51 void __user *buffer, size_t *lenp, 52 loff_t *ppos); 53 extern int proc_dointvec_jiffies(struct ctl_table *, int, 54 void __user *, size_t *, loff_t *); 55 extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int, 56 void __user *, size_t *, loff_t *); 57 extern int proc_dointvec_ms_jiffies(struct ctl_table *, int, 58 void __user *, size_t *, loff_t *); 59 extern int proc_doulongvec_minmax(struct ctl_table *, int, 60 void __user *, size_t *, loff_t *); 61 extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, 62 void __user *, size_t *, loff_t *); 63 extern int proc_do_large_bitmap(struct ctl_table *, int, 64 void __user *, size_t *, loff_t *); 65 66 /* 67 * Register a set of sysctl names by calling register_sysctl_table 68 * with an initialised array of struct ctl_table's. An entry with 69 * NULL procname terminates the table. table->de will be 70 * set up by the registration and need not be initialised in advance. 71 * 72 * sysctl names can be mirrored automatically under /proc/sys. The 73 * procname supplied controls /proc naming. 74 * 75 * The table's mode will be honoured both for sys_sysctl(2) and 76 * proc-fs access. 77 * 78 * Leaf nodes in the sysctl tree will be represented by a single file 79 * under /proc; non-leaf nodes will be represented by directories. A 80 * null procname disables /proc mirroring at this node. 81 * 82 * sysctl(2) can automatically manage read and write requests through 83 * the sysctl table. The data and maxlen fields of the ctl_table 84 * struct enable minimal validation of the values being written to be 85 * performed, and the mode field allows minimal authentication. 86 * 87 * There must be a proc_handler routine for any terminal nodes 88 * mirrored under /proc/sys (non-terminals are handled by a built-in 89 * directory handler). Several default handlers are available to 90 * cover common cases. 91 */ 92 93 /* Support for userspace poll() to watch for changes */ 94 struct ctl_table_poll { 95 atomic_t event; 96 wait_queue_head_t wait; 97 }; 98 99 static inline void *proc_sys_poll_event(struct ctl_table_poll *poll) 100 { 101 return (void *)(unsigned long)atomic_read(&poll->event); 102 } 103 104 #define __CTL_TABLE_POLL_INITIALIZER(name) { \ 105 .event = ATOMIC_INIT(0), \ 106 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) } 107 108 #define DEFINE_CTL_TABLE_POLL(name) \ 109 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name) 110 111 /* A sysctl table is an array of struct ctl_table: */ 112 struct ctl_table 113 { 114 const char *procname; /* Text ID for /proc/sys, or zero */ 115 void *data; 116 int maxlen; 117 umode_t mode; 118 struct ctl_table *child; /* Deprecated */ 119 proc_handler *proc_handler; /* Callback for text formatting */ 120 struct ctl_table_poll *poll; 121 void *extra1; 122 void *extra2; 123 } __randomize_layout; 124 125 struct ctl_node { 126 struct rb_node node; 127 struct ctl_table_header *header; 128 }; 129 130 /* struct ctl_table_header is used to maintain dynamic lists of 131 struct ctl_table trees. */ 132 struct ctl_table_header 133 { 134 union { 135 struct { 136 struct ctl_table *ctl_table; 137 int used; 138 int count; 139 int nreg; 140 }; 141 struct rcu_head rcu; 142 }; 143 struct completion *unregistering; 144 struct ctl_table *ctl_table_arg; 145 struct ctl_table_root *root; 146 struct ctl_table_set *set; 147 struct ctl_dir *parent; 148 struct ctl_node *node; 149 struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */ 150 }; 151 152 struct ctl_dir { 153 /* Header must be at the start of ctl_dir */ 154 struct ctl_table_header header; 155 struct rb_root root; 156 }; 157 158 struct ctl_table_set { 159 int (*is_seen)(struct ctl_table_set *); 160 struct ctl_dir dir; 161 }; 162 163 struct ctl_table_root { 164 struct ctl_table_set default_set; 165 struct ctl_table_set *(*lookup)(struct ctl_table_root *root); 166 void (*set_ownership)(struct ctl_table_header *head, 167 struct ctl_table *table, 168 kuid_t *uid, kgid_t *gid); 169 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table); 170 }; 171 172 /* struct ctl_path describes where in the hierarchy a table is added */ 173 struct ctl_path { 174 const char *procname; 175 }; 176 177 #ifdef CONFIG_SYSCTL 178 179 void proc_sys_poll_notify(struct ctl_table_poll *poll); 180 181 extern void setup_sysctl_set(struct ctl_table_set *p, 182 struct ctl_table_root *root, 183 int (*is_seen)(struct ctl_table_set *)); 184 extern void retire_sysctl_set(struct ctl_table_set *set); 185 186 struct ctl_table_header *__register_sysctl_table( 187 struct ctl_table_set *set, 188 const char *path, struct ctl_table *table); 189 struct ctl_table_header *__register_sysctl_paths( 190 struct ctl_table_set *set, 191 const struct ctl_path *path, struct ctl_table *table); 192 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table); 193 struct ctl_table_header *register_sysctl_table(struct ctl_table * table); 194 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 195 struct ctl_table *table); 196 197 void unregister_sysctl_table(struct ctl_table_header * table); 198 199 extern int sysctl_init(void); 200 201 extern struct ctl_table sysctl_mount_point[]; 202 203 #else /* CONFIG_SYSCTL */ 204 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table) 205 { 206 return NULL; 207 } 208 209 static inline struct ctl_table_header *register_sysctl_paths( 210 const struct ctl_path *path, struct ctl_table *table) 211 { 212 return NULL; 213 } 214 215 static inline void unregister_sysctl_table(struct ctl_table_header * table) 216 { 217 } 218 219 static inline void setup_sysctl_set(struct ctl_table_set *p, 220 struct ctl_table_root *root, 221 int (*is_seen)(struct ctl_table_set *)) 222 { 223 } 224 225 #endif /* CONFIG_SYSCTL */ 226 227 int sysctl_max_threads(struct ctl_table *table, int write, 228 void __user *buffer, size_t *lenp, loff_t *ppos); 229 230 #endif /* _LINUX_SYSCTL_H */ 231