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_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *); 52 int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *); 53 int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *); 54 int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer, 55 size_t *lenp, loff_t *ppos); 56 int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *); 57 int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *, 58 loff_t *); 59 int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *, 60 loff_t *); 61 int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *); 62 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *, 63 size_t *, loff_t *); 64 int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *); 65 int proc_do_static_key(struct ctl_table *table, int write, void *buffer, 66 size_t *lenp, loff_t *ppos); 67 68 /* 69 * Register a set of sysctl names by calling register_sysctl_table 70 * with an initialised array of struct ctl_table's. An entry with 71 * NULL procname terminates the table. table->de will be 72 * set up by the registration and need not be initialised in advance. 73 * 74 * sysctl names can be mirrored automatically under /proc/sys. The 75 * procname supplied controls /proc naming. 76 * 77 * The table's mode will be honoured for proc-fs access. 78 * 79 * Leaf nodes in the sysctl tree will be represented by a single file 80 * under /proc; non-leaf nodes will be represented by directories. A 81 * null procname disables /proc mirroring at this node. 82 * 83 * 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 const char *procname; /* Text ID for /proc/sys, or zero */ 114 void *data; 115 int maxlen; 116 umode_t mode; 117 struct ctl_table *child; /* Deprecated */ 118 proc_handler *proc_handler; /* Callback for text formatting */ 119 struct ctl_table_poll *poll; 120 void *extra1; 121 void *extra2; 122 } __randomize_layout; 123 124 struct ctl_node { 125 struct rb_node node; 126 struct ctl_table_header *header; 127 }; 128 129 /* struct ctl_table_header is used to maintain dynamic lists of 130 struct ctl_table trees. */ 131 struct ctl_table_header { 132 union { 133 struct { 134 struct ctl_table *ctl_table; 135 int used; 136 int count; 137 int nreg; 138 }; 139 struct rcu_head rcu; 140 }; 141 struct completion *unregistering; 142 struct ctl_table *ctl_table_arg; 143 struct ctl_table_root *root; 144 struct ctl_table_set *set; 145 struct ctl_dir *parent; 146 struct ctl_node *node; 147 struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */ 148 }; 149 150 struct ctl_dir { 151 /* Header must be at the start of ctl_dir */ 152 struct ctl_table_header header; 153 struct rb_root root; 154 }; 155 156 struct ctl_table_set { 157 int (*is_seen)(struct ctl_table_set *); 158 struct ctl_dir dir; 159 }; 160 161 struct ctl_table_root { 162 struct ctl_table_set default_set; 163 struct ctl_table_set *(*lookup)(struct ctl_table_root *root); 164 void (*set_ownership)(struct ctl_table_header *head, 165 struct ctl_table *table, 166 kuid_t *uid, kgid_t *gid); 167 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table); 168 }; 169 170 /* struct ctl_path describes where in the hierarchy a table is added */ 171 struct ctl_path { 172 const char *procname; 173 }; 174 175 #ifdef CONFIG_SYSCTL 176 177 void proc_sys_poll_notify(struct ctl_table_poll *poll); 178 179 extern void setup_sysctl_set(struct ctl_table_set *p, 180 struct ctl_table_root *root, 181 int (*is_seen)(struct ctl_table_set *)); 182 extern void retire_sysctl_set(struct ctl_table_set *set); 183 184 struct ctl_table_header *__register_sysctl_table( 185 struct ctl_table_set *set, 186 const char *path, struct ctl_table *table); 187 struct ctl_table_header *__register_sysctl_paths( 188 struct ctl_table_set *set, 189 const struct ctl_path *path, struct ctl_table *table); 190 struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table); 191 struct ctl_table_header *register_sysctl_table(struct ctl_table * table); 192 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 193 struct ctl_table *table); 194 195 void unregister_sysctl_table(struct ctl_table_header * table); 196 197 extern int sysctl_init(void); 198 void do_sysctl_args(void); 199 200 extern int pwrsw_enabled; 201 extern int unaligned_enabled; 202 extern int unaligned_dump_stack; 203 extern int no_unaligned_warning; 204 205 extern struct ctl_table sysctl_mount_point[]; 206 extern struct ctl_table random_table[]; 207 extern struct ctl_table firmware_config_table[]; 208 extern struct ctl_table epoll_table[]; 209 210 #else /* CONFIG_SYSCTL */ 211 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table) 212 { 213 return NULL; 214 } 215 216 static inline struct ctl_table_header *register_sysctl_paths( 217 const struct ctl_path *path, struct ctl_table *table) 218 { 219 return NULL; 220 } 221 222 static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 223 { 224 return NULL; 225 } 226 227 static inline void unregister_sysctl_table(struct ctl_table_header * table) 228 { 229 } 230 231 static inline void setup_sysctl_set(struct ctl_table_set *p, 232 struct ctl_table_root *root, 233 int (*is_seen)(struct ctl_table_set *)) 234 { 235 } 236 237 static inline void do_sysctl_args(void) 238 { 239 } 240 #endif /* CONFIG_SYSCTL */ 241 242 int sysctl_max_threads(struct ctl_table *table, int write, void *buffer, 243 size_t *lenp, loff_t *ppos); 244 245 #endif /* _LINUX_SYSCTL_H */ 246