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 */ 33struct completion; 34struct ctl_table; 35struct nsproxy; 36struct ctl_table_root; 37struct ctl_table_header; 38struct 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 56extern 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 62extern const unsigned long sysctl_long_vals[]; 63 64typedef int proc_handler(struct ctl_table *ctl, int write, void *buffer, 65 size_t *lenp, loff_t *ppos); 66 67int proc_dostring(struct ctl_table *, int, void *, size_t *, loff_t *); 68int proc_dobool(struct ctl_table *table, int write, void *buffer, 69 size_t *lenp, loff_t *ppos); 70int proc_dointvec(struct ctl_table *, int, void *, size_t *, loff_t *); 71int proc_douintvec(struct ctl_table *, int, void *, size_t *, loff_t *); 72int proc_dointvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *); 73int proc_douintvec_minmax(struct ctl_table *table, int write, void *buffer, 74 size_t *lenp, loff_t *ppos); 75int proc_dou8vec_minmax(struct ctl_table *table, int write, void *buffer, 76 size_t *lenp, loff_t *ppos); 77int proc_dointvec_jiffies(struct ctl_table *, int, void *, size_t *, loff_t *); 78int proc_dointvec_ms_jiffies_minmax(struct ctl_table *table, int write, 79 void *buffer, size_t *lenp, loff_t *ppos); 80int proc_dointvec_userhz_jiffies(struct ctl_table *, int, void *, size_t *, 81 loff_t *); 82int proc_dointvec_ms_jiffies(struct ctl_table *, int, void *, size_t *, 83 loff_t *); 84int proc_doulongvec_minmax(struct ctl_table *, int, void *, size_t *, loff_t *); 85int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, void *, 86 size_t *, loff_t *); 87int proc_do_large_bitmap(struct ctl_table *, int, void *, size_t *, loff_t *); 88int 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 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 */ 117struct ctl_table_poll { 118 atomic_t event; 119 wait_queue_head_t wait; 120}; 121 122static 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: */ 135struct ctl_table { 136 const char *procname; /* Text ID for /proc/sys, or zero */ 137 void *data; 138 int maxlen; 139 umode_t mode; 140 /** 141 * enum type - Enumeration to differentiate between ctl target types 142 * @SYSCTL_TABLE_TYPE_DEFAULT: ctl target with no special considerations 143 * @SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY: Used to identify a permanently 144 * empty directory target to serve 145 * as mount point. 146 */ 147 enum { 148 SYSCTL_TABLE_TYPE_DEFAULT, 149 SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY 150 } type; 151 proc_handler *proc_handler; /* Callback for text formatting */ 152 struct ctl_table_poll *poll; 153 void *extra1; 154 void *extra2; 155} __randomize_layout; 156 157struct ctl_node { 158 struct rb_node node; 159 struct ctl_table_header *header; 160}; 161 162/** 163 * struct ctl_table_header - maintains dynamic lists of struct ctl_table trees 164 * @ctl_table: pointer to the first element in ctl_table array 165 * @ctl_table_size: number of elements pointed by @ctl_table 166 * @used: The entry will never be touched when equal to 0. 167 * @count: Upped every time something is added to @inodes and downed every time 168 * something is removed from inodes 169 * @nreg: When nreg drops to 0 the ctl_table_header will be unregistered. 170 * @rcu: Delays the freeing of the inode. Introduced with "unfuck proc_sysctl ->d_compare()" 171 * 172 */ 173struct ctl_table_header { 174 union { 175 struct { 176 struct ctl_table *ctl_table; 177 int ctl_table_size; 178 int used; 179 int count; 180 int nreg; 181 }; 182 struct rcu_head rcu; 183 }; 184 struct completion *unregistering; 185 struct ctl_table *ctl_table_arg; 186 struct ctl_table_root *root; 187 struct ctl_table_set *set; 188 struct ctl_dir *parent; 189 struct ctl_node *node; 190 struct hlist_head inodes; /* head for proc_inode->sysctl_inodes */ 191}; 192 193struct ctl_dir { 194 /* Header must be at the start of ctl_dir */ 195 struct ctl_table_header header; 196 struct rb_root root; 197}; 198 199struct ctl_table_set { 200 int (*is_seen)(struct ctl_table_set *); 201 struct ctl_dir dir; 202}; 203 204struct ctl_table_root { 205 struct ctl_table_set default_set; 206 struct ctl_table_set *(*lookup)(struct ctl_table_root *root); 207 void (*set_ownership)(struct ctl_table_header *head, 208 struct ctl_table *table, 209 kuid_t *uid, kgid_t *gid); 210 int (*permissions)(struct ctl_table_header *head, struct ctl_table *table); 211}; 212 213#define register_sysctl(path, table) \ 214 register_sysctl_sz(path, table, ARRAY_SIZE(table)) 215 216#ifdef CONFIG_SYSCTL 217 218void proc_sys_poll_notify(struct ctl_table_poll *poll); 219 220extern void setup_sysctl_set(struct ctl_table_set *p, 221 struct ctl_table_root *root, 222 int (*is_seen)(struct ctl_table_set *)); 223extern void retire_sysctl_set(struct ctl_table_set *set); 224 225struct ctl_table_header *__register_sysctl_table( 226 struct ctl_table_set *set, 227 const char *path, struct ctl_table *table, size_t table_size); 228struct ctl_table_header *register_sysctl_sz(const char *path, struct ctl_table *table, 229 size_t table_size); 230void unregister_sysctl_table(struct ctl_table_header * table); 231 232extern int sysctl_init_bases(void); 233extern void __register_sysctl_init(const char *path, struct ctl_table *table, 234 const char *table_name, size_t table_size); 235#define register_sysctl_init(path, table) \ 236 __register_sysctl_init(path, table, #table, ARRAY_SIZE(table)) 237extern struct ctl_table_header *register_sysctl_mount_point(const char *path); 238 239void do_sysctl_args(void); 240bool sysctl_is_alias(char *param); 241int 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 248extern int pwrsw_enabled; 249extern int unaligned_enabled; 250extern int unaligned_dump_stack; 251extern int no_unaligned_warning; 252 253#else /* CONFIG_SYSCTL */ 254 255static inline void register_sysctl_init(const char *path, struct ctl_table *table) 256{ 257} 258 259static inline struct ctl_table_header *register_sysctl_mount_point(const char *path) 260{ 261 return NULL; 262} 263 264static inline struct ctl_table_header *register_sysctl_sz(const char *path, 265 struct ctl_table *table, 266 size_t table_size) 267{ 268 return NULL; 269} 270 271static inline void unregister_sysctl_table(struct ctl_table_header * table) 272{ 273} 274 275static inline void setup_sysctl_set(struct ctl_table_set *p, 276 struct ctl_table_root *root, 277 int (*is_seen)(struct ctl_table_set *)) 278{ 279} 280 281static inline void do_sysctl_args(void) 282{ 283} 284 285static inline bool sysctl_is_alias(char *param) 286{ 287 return false; 288} 289#endif /* CONFIG_SYSCTL */ 290 291int sysctl_max_threads(struct ctl_table *table, int write, void *buffer, 292 size_t *lenp, loff_t *ppos); 293 294#endif /* _LINUX_SYSCTL_H */ 295