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_userhz_jiffies(struct ctl_table *, int, void *, size_t *, 79 loff_t *); 80 int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *, 81 loff_t *); 82 int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *); 83 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *, 84 size_t *, loff_t *); 85 int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *); 86 int proc_do_static_key(struct ctl_table *table, int write, void *buffer, 87 size_t *lenp, loff_t *ppos); 88 89 /* 90 * Register a set of sysctl names by calling register_sysctl_table 91 * with an initialised array of struct ctl_table's. An entry with 92 * NULL procname terminates the table. table->de will be 93 * set up by the registration and need not be initialised in advance. 94 * 95 * sysctl names can be mirrored automatically under /proc/sys. The 96 * procname supplied controls /proc naming. 97 * 98 * The table's mode will be honoured for proc-fs access. 99 * 100 * Leaf nodes in the sysctl tree will be represented by a single file 101 * under /proc; non-leaf nodes will be represented by directories. A 102 * null procname disables /proc mirroring at this node. 103 * 104 * The data and maxlen fields of the ctl_table 105 * struct enable minimal validation of the values being written to be 106 * performed, and the mode field allows minimal authentication. 107 * 108 * There must be a proc_handler routine for any terminal nodes 109 * mirrored under /proc/sys (non-terminals are handled by a built-in 110 * directory handler). Several default handlers are available to 111 * cover common cases. 112 */ 113 114 /* Support for userspace poll() to watch for changes */ 115 struct ctl_table_poll { 116 atomic_t event; 117 wait_queue_head_t wait; 118 }; 119 120 static inline void *proc_sys_poll_event(struct ctl_table_poll *poll) 121 { 122 return (void *)(unsigned long)atomic_read(&poll->event); 123 } 124 125 #define __CTL_TABLE_POLL_INITIALIZER(name) { \ 126 .event = ATOMIC_INIT(0), \ 127 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) } 128 129 #define DEFINE_CTL_TABLE_POLL(name) \ 130 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name) 131 132 /* A sysctl table is an array of struct ctl_table: */ 133 struct ctl_table { 134 const char *procname; /* Text ID for /proc/sys, or zero */ 135 void *data; 136 int maxlen; 137 umode_t mode; 138 struct ctl_table *child; /* Deprecated */ 139 proc_handler *proc_handler; /* Callback for text formatting */ 140 struct ctl_table_poll *poll; 141 void *extra1; 142 void *extra2; 143 } __randomize_layout; 144 145 struct ctl_node { 146 struct rb_node node; 147 struct ctl_table_header *header; 148 }; 149 150 /* struct ctl_table_header is used to maintain dynamic lists of 151 struct ctl_table trees. */ 152 struct ctl_table_header { 153 union { 154 struct { 155 struct ctl_table *ctl_table; 156 int used; 157 int count; 158 int nreg; 159 }; 160 struct rcu_head rcu; 161 }; 162 struct completion *unregistering; 163 struct ctl_table *ctl_table_arg; 164 struct ctl_table_root *root; 165 struct ctl_table_set *set; 166 struct ctl_dir *parent; 167 struct ctl_node *node; 168 struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */ 169 }; 170 171 struct ctl_dir { 172 /* Header must be at the start of ctl_dir */ 173 struct ctl_table_header header; 174 struct rb_root root; 175 }; 176 177 struct ctl_table_set { 178 int (*is_seen)(struct ctl_table_set *); 179 struct ctl_dir dir; 180 }; 181 182 struct ctl_table_root { 183 struct ctl_table_set default_set; 184 struct ctl_table_set *(*lookup)(struct ctl_table_root *root); 185 void (*set_ownership)(struct ctl_table_header *head, 186 struct ctl_table *table, 187 kuid_t *uid, kgid_t *gid); 188 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table); 189 }; 190 191 /* struct ctl_path describes where in the hierarchy a table is added */ 192 struct ctl_path { 193 const char *procname; 194 }; 195 196 #ifdef CONFIG_SYSCTL 197 198 #define DECLARE_SYSCTL_BASE(_name, _table) \ 199 static struct ctl_table _name##_base_table[] = { \ 200 { \ 201 .procname = #_name, \ 202 .mode = 0555, \ 203 .child = _table, \ 204 }, \ 205 { }, \ 206 } 207 208 extern int __register_sysctl_base(struct ctl_table *base_table); 209 210 #define register_sysctl_base(_name) __register_sysctl_base(_name##_base_table) 211 212 void proc_sys_poll_notify(struct ctl_table_poll *poll); 213 214 extern void setup_sysctl_set(struct ctl_table_set *p, 215 struct ctl_table_root *root, 216 int (*is_seen)(struct ctl_table_set *)); 217 extern void retire_sysctl_set(struct ctl_table_set *set); 218 219 struct ctl_table_header *__register_sysctl_table( 220 struct ctl_table_set *set, 221 const char *path, struct ctl_table *table); 222 struct ctl_table_header *__register_sysctl_paths( 223 struct ctl_table_set *set, 224 const struct ctl_path *path, struct ctl_table *table); 225 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table); 226 struct ctl_table_header *register_sysctl_table(struct ctl_table * table); 227 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 228 struct ctl_table *table); 229 230 void unregister_sysctl_table(struct ctl_table_header * table); 231 232 extern int sysctl_init_bases(void); 233 extern void __register_sysctl_init(const char *path, struct ctl_table *table, 234 const char *table_name); 235 #define register_sysctl_init(path, table) __register_sysctl_init(path, table, #table) 236 extern struct ctl_table_header *register_sysctl_mount_point(const char *path); 237 238 void do_sysctl_args(void); 239 int do_proc_douintvec(struct ctl_table *table, int write, 240 void *buffer, size_t *lenp, loff_t *ppos, 241 int (*conv)(unsigned long *lvalp, 242 unsigned int *valp, 243 int write, void *data), 244 void *data); 245 246 extern int pwrsw_enabled; 247 extern int unaligned_enabled; 248 extern int unaligned_dump_stack; 249 extern int no_unaligned_warning; 250 251 extern struct ctl_table sysctl_mount_point[]; 252 253 #else /* CONFIG_SYSCTL */ 254 255 #define DECLARE_SYSCTL_BASE(_name, _table) 256 257 static inline int __register_sysctl_base(struct ctl_table *base_table) 258 { 259 return 0; 260 } 261 262 #define register_sysctl_base(table) __register_sysctl_base(table) 263 264 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table) 265 { 266 return NULL; 267 } 268 269 static inline struct ctl_table_header *register_sysctl_mount_point(const char *path) 270 { 271 return NULL; 272 } 273 274 static inline struct ctl_table_header *register_sysctl_paths( 275 const struct ctl_path *path, struct ctl_table *table) 276 { 277 return NULL; 278 } 279 280 static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 281 { 282 return NULL; 283 } 284 285 static inline void unregister_sysctl_table(struct ctl_table_header * table) 286 { 287 } 288 289 static inline void setup_sysctl_set(struct ctl_table_set *p, 290 struct ctl_table_root *root, 291 int (*is_seen)(struct ctl_table_set *)) 292 { 293 } 294 295 static inline void do_sysctl_args(void) 296 { 297 } 298 #endif /* CONFIG_SYSCTL */ 299 300 int sysctl_max_threads(struct ctl_table *table, int write, void *buffer, 301 size_t *lenp, loff_t *ppos); 302 303 #endif /* _LINUX_SYSCTL_H */ 304