1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * sysctl.h: General linux system control interface 4 * 5 * Begun 24 March 1995, Stephen Tweedie 6 * 7 **************************************************************** 8 **************************************************************** 9 ** 10 ** WARNING: 11 ** The values in this file are exported to user space via 12 ** the sysctl() binary interface. Do *NOT* change the 13 ** numbering of any existing values here, and do not change 14 ** any numbers within any one set of values. If you have to 15 ** redefine an existing interface, use a new number for it. 16 ** The kernel will then return -ENOTDIR to any application using 17 ** the old binary interface. 18 ** 19 **************************************************************** 20 **************************************************************** 21 */ 22 #ifndef _LINUX_SYSCTL_H 23 #define _LINUX_SYSCTL_H 24 25 #include <linux/list.h> 26 #include <linux/rcupdate.h> 27 #include <linux/wait.h> 28 #include <linux/rbtree.h> 29 #include <linux/uidgid.h> 30 #include <uapi/linux/sysctl.h> 31 32 /* For the /proc/sys support */ 33 struct completion; 34 struct ctl_table; 35 struct nsproxy; 36 struct ctl_table_root; 37 struct ctl_table_header; 38 struct ctl_dir; 39 40 /* Keep the same order as in fs/proc/proc_sysctl.c */ 41 #define SYSCTL_ZERO ((void *)&sysctl_vals[0]) 42 #define SYSCTL_ONE ((void *)&sysctl_vals[1]) 43 #define SYSCTL_TWO ((void *)&sysctl_vals[2]) 44 #define SYSCTL_THREE ((void *)&sysctl_vals[3]) 45 #define SYSCTL_FOUR ((void *)&sysctl_vals[4]) 46 #define SYSCTL_ONE_HUNDRED ((void *)&sysctl_vals[5]) 47 #define SYSCTL_TWO_HUNDRED ((void *)&sysctl_vals[6]) 48 #define SYSCTL_ONE_THOUSAND ((void *)&sysctl_vals[7]) 49 #define SYSCTL_THREE_THOUSAND ((void *)&sysctl_vals[8]) 50 #define SYSCTL_INT_MAX ((void *)&sysctl_vals[9]) 51 52 /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */ 53 #define SYSCTL_MAXOLDUID ((void *)&sysctl_vals[10]) 54 #define SYSCTL_NEG_ONE ((void *)&sysctl_vals[11]) 55 56 extern const int sysctl_vals[]; 57 58 #define SYSCTL_LONG_ZERO ((void *)&sysctl_long_vals[0]) 59 #define SYSCTL_LONG_ONE ((void *)&sysctl_long_vals[1]) 60 #define SYSCTL_LONG_MAX ((void *)&sysctl_long_vals[2]) 61 62 extern const unsigned long sysctl_long_vals[]; 63 64 typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer, 65 size_t *lenp, loff_t *ppos); 66 67 int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *); 68 int proc_dobool(struct ctl_table *table, int write, void *buffer, 69 size_t *lenp, loff_t *ppos); 70 int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *); 71 int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *); 72 int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *); 73 int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer, 74 size_t *lenp, loff_t *ppos); 75 int proc_dou8vec_minmax(struct ctl_table *table, int write, void *buffer, 76 size_t *lenp, loff_t *ppos); 77 int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *); 78 int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write, 79 void *buffer, size_t *lenp, loff_t *ppos); 80 int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *, 81 loff_t *); 82 int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *, 83 loff_t *); 84 int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *); 85 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *, 86 size_t *, loff_t *); 87 int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *); 88 int proc_do_static_key(struct ctl_table *table, int write, void *buffer, 89 size_t *lenp, loff_t *ppos); 90 91 /* 92 * Register a set of sysctl names by calling register_sysctl_table 93 * with an initialised array of struct ctl_table's. An entry with 94 * NULL procname terminates the table. table->de will be 95 * set up by the registration and need not be initialised in advance. 96 * 97 * sysctl names can be mirrored automatically under /proc/sys. The 98 * procname supplied controls /proc naming. 99 * 100 * The table's mode will be honoured for proc-fs access. 101 * 102 * Leaf nodes in the sysctl tree will be represented by a single file 103 * under /proc; non-leaf nodes will be represented by directories. A 104 * null procname disables /proc mirroring at this node. 105 * 106 * The data and maxlen fields of the ctl_table 107 * struct enable minimal validation of the values being written to be 108 * performed, and the mode field allows minimal authentication. 109 * 110 * There must be a proc_handler routine for any terminal nodes 111 * mirrored under /proc/sys (non-terminals are handled by a built-in 112 * directory handler). Several default handlers are available to 113 * cover common cases. 114 */ 115 116 /* Support for userspace poll() to watch for changes */ 117 struct ctl_table_poll { 118 atomic_t event; 119 wait_queue_head_t wait; 120 }; 121 122 static inline void *proc_sys_poll_event(struct ctl_table_poll *poll) 123 { 124 return (void *)(unsigned long)atomic_read(&poll->event); 125 } 126 127 #define __CTL_TABLE_POLL_INITIALIZER(name) { \ 128 .event = ATOMIC_INIT(0), \ 129 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) } 130 131 #define DEFINE_CTL_TABLE_POLL(name) \ 132 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name) 133 134 /* A sysctl table is an array of struct ctl_table: */ 135 struct ctl_table { 136 const char *procname; /* Text ID for /proc/sys, or zero */ 137 void *data; 138 int maxlen; 139 umode_t mode; 140 struct ctl_table *child; /* Deprecated */ 141 proc_handler *proc_handler; /* Callback for text formatting */ 142 struct ctl_table_poll *poll; 143 void *extra1; 144 void *extra2; 145 } __randomize_layout; 146 147 struct ctl_node { 148 struct rb_node node; 149 struct ctl_table_header *header; 150 }; 151 152 /* struct ctl_table_header is used to maintain dynamic lists of 153 struct ctl_table trees. */ 154 struct ctl_table_header { 155 union { 156 struct { 157 struct ctl_table *ctl_table; 158 int used; 159 int count; 160 int nreg; 161 }; 162 struct rcu_head rcu; 163 }; 164 struct completion *unregistering; 165 struct ctl_table *ctl_table_arg; 166 struct ctl_table_root *root; 167 struct ctl_table_set *set; 168 struct ctl_dir *parent; 169 struct ctl_node *node; 170 struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */ 171 }; 172 173 struct ctl_dir { 174 /* Header must be at the start of ctl_dir */ 175 struct ctl_table_header header; 176 struct rb_root root; 177 }; 178 179 struct ctl_table_set { 180 int (*is_seen)(struct ctl_table_set *); 181 struct ctl_dir dir; 182 }; 183 184 struct ctl_table_root { 185 struct ctl_table_set default_set; 186 struct ctl_table_set *(*lookup)(struct ctl_table_root *root); 187 void (*set_ownership)(struct ctl_table_header *head, 188 struct ctl_table *table, 189 kuid_t *uid, kgid_t *gid); 190 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table); 191 }; 192 193 /* struct ctl_path describes where in the hierarchy a table is added */ 194 struct ctl_path { 195 const char *procname; 196 }; 197 198 #ifdef CONFIG_SYSCTL 199 200 #define DECLARE_SYSCTL_BASE(_name, _table) \ 201 static struct ctl_table _name##_base_table[] = { \ 202 { \ 203 .procname = #_name, \ 204 .mode = 0555, \ 205 .child = _table, \ 206 }, \ 207 { }, \ 208 } 209 210 extern int __register_sysctl_base(struct ctl_table *base_table); 211 212 #define register_sysctl_base(_name) __register_sysctl_base(_name##_base_table) 213 214 void proc_sys_poll_notify(struct ctl_table_poll *poll); 215 216 extern void setup_sysctl_set(struct ctl_table_set *p, 217 struct ctl_table_root *root, 218 int (*is_seen)(struct ctl_table_set *)); 219 extern void retire_sysctl_set(struct ctl_table_set *set); 220 221 struct ctl_table_header *__register_sysctl_table( 222 struct ctl_table_set *set, 223 const char *path, struct ctl_table *table); 224 struct ctl_table_header *__register_sysctl_paths( 225 struct ctl_table_set *set, 226 const struct ctl_path *path, struct ctl_table *table); 227 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table); 228 struct ctl_table_header *register_sysctl_table(struct ctl_table * table); 229 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 230 struct ctl_table *table); 231 232 void unregister_sysctl_table(struct ctl_table_header * table); 233 234 extern int sysctl_init_bases(void); 235 extern void __register_sysctl_init(const char *path, struct ctl_table *table, 236 const char *table_name); 237 #define register_sysctl_init(path, table) __register_sysctl_init(path, table, #table) 238 extern struct ctl_table_header *register_sysctl_mount_point(const char *path); 239 240 void do_sysctl_args(void); 241 int do_proc_douintvec(struct ctl_table *table, int write, 242 void *buffer, size_t *lenp, loff_t *ppos, 243 int (*conv)(unsigned long *lvalp, 244 unsigned int *valp, 245 int write, void *data), 246 void *data); 247 248 extern int pwrsw_enabled; 249 extern int unaligned_enabled; 250 extern int unaligned_dump_stack; 251 extern int no_unaligned_warning; 252 253 extern struct ctl_table sysctl_mount_point[]; 254 255 #else /* CONFIG_SYSCTL */ 256 257 #define DECLARE_SYSCTL_BASE(_name, _table) 258 259 static inline int __register_sysctl_base(struct ctl_table *base_table) 260 { 261 return 0; 262 } 263 264 #define register_sysctl_base(table) __register_sysctl_base(table) 265 266 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table) 267 { 268 return NULL; 269 } 270 271 static inline void register_sysctl_init(const char *path, struct ctl_table *table) 272 { 273 } 274 275 static inline struct ctl_table_header *register_sysctl_mount_point(const char *path) 276 { 277 return NULL; 278 } 279 280 static inline struct ctl_table_header *register_sysctl_paths( 281 const struct ctl_path *path, struct ctl_table *table) 282 { 283 return NULL; 284 } 285 286 static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 287 { 288 return NULL; 289 } 290 291 static inline void unregister_sysctl_table(struct ctl_table_header * table) 292 { 293 } 294 295 static inline void setup_sysctl_set(struct ctl_table_set *p, 296 struct ctl_table_root *root, 297 int (*is_seen)(struct ctl_table_set *)) 298 { 299 } 300 301 static inline void do_sysctl_args(void) 302 { 303 } 304 #endif /* CONFIG_SYSCTL */ 305 306 int sysctl_max_threads(struct ctl_table *table, int write, void *buffer, 307 size_t *lenp, loff_t *ppos); 308 309 #endif /* _LINUX_SYSCTL_H */ 310