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_INT_MAX ((void *)&sysctl_vals[2]) 44 45 extern const int sysctl_vals[]; 46 47 typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer, 48 size_t *lenp, loff_t *ppos); 49 50 int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *); 51 int proc_dobool(struct ctl_table *table, int write, void *buffer, 52 size_t *lenp, loff_t *ppos); 53 int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *); 54 int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *); 55 int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *); 56 int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer, 57 size_t *lenp, loff_t *ppos); 58 int proc_dou8vec_minmax(struct ctl_table *table, int write, void *buffer, 59 size_t *lenp, loff_t *ppos); 60 int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *); 61 int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *, 62 loff_t *); 63 int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *, 64 loff_t *); 65 int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *); 66 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *, 67 size_t *, loff_t *); 68 int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *); 69 int proc_do_static_key(struct ctl_table *table, int write, void *buffer, 70 size_t *lenp, loff_t *ppos); 71 72 /* 73 * Register a set of sysctl names by calling register_sysctl_table 74 * with an initialised array of struct ctl_table's. An entry with 75 * NULL procname terminates the table. table->de will be 76 * set up by the registration and need not be initialised in advance. 77 * 78 * sysctl names can be mirrored automatically under /proc/sys. The 79 * procname supplied controls /proc naming. 80 * 81 * The table's mode will be honoured for proc-fs access. 82 * 83 * Leaf nodes in the sysctl tree will be represented by a single file 84 * under /proc; non-leaf nodes will be represented by directories. A 85 * null procname disables /proc mirroring at this node. 86 * 87 * The data and maxlen fields of the ctl_table 88 * struct enable minimal validation of the values being written to be 89 * performed, and the mode field allows minimal authentication. 90 * 91 * There must be a proc_handler routine for any terminal nodes 92 * mirrored under /proc/sys (non-terminals are handled by a built-in 93 * directory handler). Several default handlers are available to 94 * cover common cases. 95 */ 96 97 /* Support for userspace poll() to watch for changes */ 98 struct ctl_table_poll { 99 atomic_t event; 100 wait_queue_head_t wait; 101 }; 102 103 static inline void *proc_sys_poll_event(struct ctl_table_poll *poll) 104 { 105 return (void *)(unsigned long)atomic_read(&poll->event); 106 } 107 108 #define __CTL_TABLE_POLL_INITIALIZER(name) { \ 109 .event = ATOMIC_INIT(0), \ 110 .wait = __WAIT_QUEUE_HEAD_INITIALIZER(name.wait) } 111 112 #define DEFINE_CTL_TABLE_POLL(name) \ 113 struct ctl_table_poll name = __CTL_TABLE_POLL_INITIALIZER(name) 114 115 /* A sysctl table is an array of struct ctl_table: */ 116 struct ctl_table { 117 const char *procname; /* Text ID for /proc/sys, or zero */ 118 void *data; 119 int maxlen; 120 umode_t mode; 121 struct ctl_table *child; /* Deprecated */ 122 proc_handler *proc_handler; /* Callback for text formatting */ 123 struct ctl_table_poll *poll; 124 void *extra1; 125 void *extra2; 126 } __randomize_layout; 127 128 struct ctl_node { 129 struct rb_node node; 130 struct ctl_table_header *header; 131 }; 132 133 /* struct ctl_table_header is used to maintain dynamic lists of 134 struct ctl_table trees. */ 135 struct ctl_table_header { 136 union { 137 struct { 138 struct ctl_table *ctl_table; 139 int used; 140 int count; 141 int nreg; 142 }; 143 struct rcu_head rcu; 144 }; 145 struct completion *unregistering; 146 struct ctl_table *ctl_table_arg; 147 struct ctl_table_root *root; 148 struct ctl_table_set *set; 149 struct ctl_dir *parent; 150 struct ctl_node *node; 151 struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */ 152 }; 153 154 struct ctl_dir { 155 /* Header must be at the start of ctl_dir */ 156 struct ctl_table_header header; 157 struct rb_root root; 158 }; 159 160 struct ctl_table_set { 161 int (*is_seen)(struct ctl_table_set *); 162 struct ctl_dir dir; 163 }; 164 165 struct ctl_table_root { 166 struct ctl_table_set default_set; 167 struct ctl_table_set *(*lookup)(struct ctl_table_root *root); 168 void (*set_ownership)(struct ctl_table_header *head, 169 struct ctl_table *table, 170 kuid_t *uid, kgid_t *gid); 171 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table); 172 }; 173 174 /* struct ctl_path describes where in the hierarchy a table is added */ 175 struct ctl_path { 176 const char *procname; 177 }; 178 179 #ifdef CONFIG_SYSCTL 180 181 void proc_sys_poll_notify(struct ctl_table_poll *poll); 182 183 extern void setup_sysctl_set(struct ctl_table_set *p, 184 struct ctl_table_root *root, 185 int (*is_seen)(struct ctl_table_set *)); 186 extern void retire_sysctl_set(struct ctl_table_set *set); 187 188 struct ctl_table_header *__register_sysctl_table( 189 struct ctl_table_set *set, 190 const char *path, struct ctl_table *table); 191 struct ctl_table_header *__register_sysctl_paths( 192 struct ctl_table_set *set, 193 const struct ctl_path *path, struct ctl_table *table); 194 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table); 195 struct ctl_table_header *register_sysctl_table(struct ctl_table * table); 196 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 197 struct ctl_table *table); 198 199 void unregister_sysctl_table(struct ctl_table_header * table); 200 201 extern int sysctl_init(void); 202 void do_sysctl_args(void); 203 204 extern int pwrsw_enabled; 205 extern int unaligned_enabled; 206 extern int unaligned_dump_stack; 207 extern int no_unaligned_warning; 208 209 extern struct ctl_table sysctl_mount_point[]; 210 extern struct ctl_table random_table[]; 211 extern struct ctl_table firmware_config_table[]; 212 extern struct ctl_table epoll_table[]; 213 214 #else /* CONFIG_SYSCTL */ 215 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table) 216 { 217 return NULL; 218 } 219 220 static inline struct ctl_table_header *register_sysctl_paths( 221 const struct ctl_path *path, struct ctl_table *table) 222 { 223 return NULL; 224 } 225 226 static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 227 { 228 return NULL; 229 } 230 231 static inline void unregister_sysctl_table(struct ctl_table_header * table) 232 { 233 } 234 235 static inline void setup_sysctl_set(struct ctl_table_set *p, 236 struct ctl_table_root *root, 237 int (*is_seen)(struct ctl_table_set *)) 238 { 239 } 240 241 static inline void do_sysctl_args(void) 242 { 243 } 244 #endif /* CONFIG_SYSCTL */ 245 246 int sysctl_max_threads(struct ctl_table *table, int write, void *buffer, 247 size_t *lenp, loff_t *ppos); 248 249 #endif /* _LINUX_SYSCTL_H */ 250