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_NEG_ONE ((void *)&sysctl_vals[0]) 42 #define SYSCTL_ZERO ((void *)&sysctl_vals[1]) 43 #define SYSCTL_ONE ((void *)&sysctl_vals[2]) 44 #define SYSCTL_TWO ((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 55 extern const int sysctl_vals[]; 56 57 #define SYSCTL_LONG_ZERO ((void *)&sysctl_long_vals[0]) 58 #define SYSCTL_LONG_ONE ((void *)&sysctl_long_vals[1]) 59 #define SYSCTL_LONG_MAX ((void *)&sysctl_long_vals[2]) 60 61 extern const unsigned long sysctl_long_vals[]; 62 63 typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer, 64 size_t *lenp, loff_t *ppos); 65 66 int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *); 67 int proc_dobool(struct ctl_table *table, int write, void *buffer, 68 size_t *lenp, loff_t *ppos); 69 int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *); 70 int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *); 71 int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *); 72 int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer, 73 size_t *lenp, loff_t *ppos); 74 int proc_dou8vec_minmax(struct ctl_table *table, int write, void *buffer, 75 size_t *lenp, loff_t *ppos); 76 int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *); 77 int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *, 78 loff_t *); 79 int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *, 80 loff_t *); 81 int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *); 82 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *, 83 size_t *, loff_t *); 84 int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *); 85 int proc_do_static_key(struct ctl_table *table, int write, void *buffer, 86 size_t *lenp, loff_t *ppos); 87 88 /* 89 * Register a set of sysctl names by calling register_sysctl_table 90 * with an initialised array of struct ctl_table's. An entry with 91 * NULL procname terminates the table. table->de will be 92 * set up by the registration and need not be initialised in advance. 93 * 94 * sysctl names can be mirrored automatically under /proc/sys. The 95 * procname supplied controls /proc naming. 96 * 97 * The table's mode will be honoured for proc-fs access. 98 * 99 * Leaf nodes in the sysctl tree will be represented by a single file 100 * under /proc; non-leaf nodes will be represented by directories. A 101 * null procname disables /proc mirroring at this node. 102 * 103 * The data and maxlen fields of the ctl_table 104 * struct enable minimal validation of the values being written to be 105 * performed, and the mode field allows minimal authentication. 106 * 107 * There must be a proc_handler routine for any terminal nodes 108 * mirrored under /proc/sys (non-terminals are handled by a built-in 109 * directory handler). Several default handlers are available to 110 * cover common cases. 111 */ 112 113 /* Support for userspace poll() to watch for changes */ 114 struct ctl_table_poll { 115 atomic_t event; 116 wait_queue_head_t wait; 117 }; 118 119 static inline void *proc_sys_poll_event(struct ctl_table_poll *poll) 120 { 121 return (void *)(unsigned long)atomic_read(&poll->event); 122 } 123 124 #define __CTL_TABLE_POLL_INITIALIZER(name) { \ 125 .event = ATOMIC_INIT(0), \ 126 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) } 127 128 #define DEFINE_CTL_TABLE_POLL(name) \ 129 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name) 130 131 /* A sysctl table is an array of struct ctl_table: */ 132 struct ctl_table { 133 const char *procname; /* Text ID for /proc/sys, or zero */ 134 void *data; 135 int maxlen; 136 umode_t mode; 137 struct ctl_table *child; /* Deprecated */ 138 proc_handler *proc_handler; /* Callback for text formatting */ 139 struct ctl_table_poll *poll; 140 void *extra1; 141 void *extra2; 142 } __randomize_layout; 143 144 struct ctl_node { 145 struct rb_node node; 146 struct ctl_table_header *header; 147 }; 148 149 /* struct ctl_table_header is used to maintain dynamic lists of 150 struct ctl_table trees. */ 151 struct ctl_table_header { 152 union { 153 struct { 154 struct ctl_table *ctl_table; 155 int used; 156 int count; 157 int nreg; 158 }; 159 struct rcu_head rcu; 160 }; 161 struct completion *unregistering; 162 struct ctl_table *ctl_table_arg; 163 struct ctl_table_root *root; 164 struct ctl_table_set *set; 165 struct ctl_dir *parent; 166 struct ctl_node *node; 167 struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */ 168 }; 169 170 struct ctl_dir { 171 /* Header must be at the start of ctl_dir */ 172 struct ctl_table_header header; 173 struct rb_root root; 174 }; 175 176 struct ctl_table_set { 177 int (*is_seen)(struct ctl_table_set *); 178 struct ctl_dir dir; 179 }; 180 181 struct ctl_table_root { 182 struct ctl_table_set default_set; 183 struct ctl_table_set *(*lookup)(struct ctl_table_root *root); 184 void (*set_ownership)(struct ctl_table_header *head, 185 struct ctl_table *table, 186 kuid_t *uid, kgid_t *gid); 187 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table); 188 }; 189 190 /* struct ctl_path describes where in the hierarchy a table is added */ 191 struct ctl_path { 192 const char *procname; 193 }; 194 195 #ifdef CONFIG_SYSCTL 196 197 #define DECLARE_SYSCTL_BASE(_name, _table) \ 198 static struct ctl_table _name##_base_table[] = { \ 199 { \ 200 .procname = #_name, \ 201 .mode = 0555, \ 202 .child = _table, \ 203 }, \ 204 { }, \ 205 } 206 207 extern int __register_sysctl_base(struct ctl_table *base_table); 208 209 #define register_sysctl_base(_name) __register_sysctl_base(_name##_base_table) 210 211 void proc_sys_poll_notify(struct ctl_table_poll *poll); 212 213 extern void setup_sysctl_set(struct ctl_table_set *p, 214 struct ctl_table_root *root, 215 int (*is_seen)(struct ctl_table_set *)); 216 extern void retire_sysctl_set(struct ctl_table_set *set); 217 218 struct ctl_table_header *__register_sysctl_table( 219 struct ctl_table_set *set, 220 const char *path, struct ctl_table *table); 221 struct ctl_table_header *__register_sysctl_paths( 222 struct ctl_table_set *set, 223 const struct ctl_path *path, struct ctl_table *table); 224 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table); 225 struct ctl_table_header *register_sysctl_table(struct ctl_table * table); 226 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 227 struct ctl_table *table); 228 229 void unregister_sysctl_table(struct ctl_table_header * table); 230 231 extern int sysctl_init_bases(void); 232 extern void __register_sysctl_init(const char *path, struct ctl_table *table, 233 const char *table_name); 234 #define register_sysctl_init(path, table) __register_sysctl_init(path, table, #table) 235 extern struct ctl_table_header *register_sysctl_mount_point(const char *path); 236 237 void do_sysctl_args(void); 238 int do_proc_douintvec(struct ctl_table *table, int write, 239 void *buffer, size_t *lenp, loff_t *ppos, 240 int (*conv)(unsigned long *lvalp, 241 unsigned int *valp, 242 int write, void *data), 243 void *data); 244 245 extern int pwrsw_enabled; 246 extern int unaligned_enabled; 247 extern int unaligned_dump_stack; 248 extern int no_unaligned_warning; 249 250 extern struct ctl_table sysctl_mount_point[]; 251 252 #else /* CONFIG_SYSCTL */ 253 254 #define DECLARE_SYSCTL_BASE(_name, _table) 255 256 static inline int __register_sysctl_base(struct ctl_table *base_table) 257 { 258 return 0; 259 } 260 261 #define register_sysctl_base(table) __register_sysctl_base(table) 262 263 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table) 264 { 265 return NULL; 266 } 267 268 static inline struct ctl_table_header *register_sysctl_mount_point(const char *path) 269 { 270 return NULL; 271 } 272 273 static inline struct ctl_table_header *register_sysctl_paths( 274 const struct ctl_path *path, struct ctl_table *table) 275 { 276 return NULL; 277 } 278 279 static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 280 { 281 return NULL; 282 } 283 284 static inline void unregister_sysctl_table(struct ctl_table_header * table) 285 { 286 } 287 288 static inline void setup_sysctl_set(struct ctl_table_set *p, 289 struct ctl_table_root *root, 290 int (*is_seen)(struct ctl_table_set *)) 291 { 292 } 293 294 static inline void do_sysctl_args(void) 295 { 296 } 297 #endif /* CONFIG_SYSCTL */ 298 299 int sysctl_max_threads(struct ctl_table *table, int write, void *buffer, 300 size_t *lenp, loff_t *ppos); 301 302 #endif /* _LINUX_SYSCTL_H */ 303