kobject.h revision 5f123fbd80f4f788554636f02bf73e40f914e0d6
1/* 2 * kobject.h - generic kernel object infrastructure. 3 * 4 * Copyright (c) 2002-2003 Patrick Mochel 5 * Copyright (c) 2002-2003 Open Source Development Labs 6 * 7 * This file is released under the GPLv2. 8 * 9 * 10 * Please read Documentation/kobject.txt before using the kobject 11 * interface, ESPECIALLY the parts about reference counts and object 12 * destructors. 13 */ 14 15#ifndef _KOBJECT_H_ 16#define _KOBJECT_H_ 17 18#ifdef __KERNEL__ 19 20#include <linux/types.h> 21#include <linux/list.h> 22#include <linux/sysfs.h> 23#include <linux/spinlock.h> 24#include <linux/rwsem.h> 25#include <linux/kref.h> 26#include <linux/kernel.h> 27#include <asm/atomic.h> 28 29#define KOBJ_NAME_LEN 20 30 31#define HOTPLUG_PATH_LEN 256 32 33/* path to the userspace helper executed on an event */ 34extern char hotplug_path[]; 35 36/* counter to tag the hotplug event, read only except for the kobject core */ 37extern u64 hotplug_seqnum; 38 39/* the actions here must match the proper string in lib/kobject_uevent.c */ 40typedef int __bitwise kobject_action_t; 41enum kobject_action { 42 KOBJ_ADD = (__force kobject_action_t) 0x01, /* exclusive to core */ 43 KOBJ_REMOVE = (__force kobject_action_t) 0x02, /* exclusive to core */ 44 KOBJ_CHANGE = (__force kobject_action_t) 0x03, /* device state change */ 45 KOBJ_OFFLINE = (__force kobject_action_t) 0x04, /* device offline */ 46 KOBJ_ONLINE = (__force kobject_action_t) 0x05, /* device online */ 47}; 48 49struct kobject { 50 const char * k_name; 51 char name[KOBJ_NAME_LEN]; 52 struct kref kref; 53 struct list_head entry; 54 struct kobject * parent; 55 struct kset * kset; 56 struct kobj_type * ktype; 57 struct dentry * dentry; 58}; 59 60extern int kobject_set_name(struct kobject *, const char *, ...) 61 __attribute__((format(printf,2,3))); 62 63static inline const char * kobject_name(const struct kobject * kobj) 64{ 65 return kobj->k_name; 66} 67 68extern void kobject_init(struct kobject *); 69extern void kobject_cleanup(struct kobject *); 70 71extern int kobject_add(struct kobject *); 72extern void kobject_del(struct kobject *); 73 74extern int kobject_rename(struct kobject *, const char *new_name); 75 76extern int kobject_register(struct kobject *); 77extern void kobject_unregister(struct kobject *); 78 79extern struct kobject * kobject_get(struct kobject *); 80extern void kobject_put(struct kobject *); 81 82extern char * kobject_get_path(struct kobject *, gfp_t); 83 84struct kobj_type { 85 void (*release)(struct kobject *); 86 struct sysfs_ops * sysfs_ops; 87 struct attribute ** default_attrs; 88}; 89 90 91/** 92 * kset - a set of kobjects of a specific type, belonging 93 * to a specific subsystem. 94 * 95 * All kobjects of a kset should be embedded in an identical 96 * type. This type may have a descriptor, which the kset points 97 * to. This allows there to exist sets of objects of the same 98 * type in different subsystems. 99 * 100 * A subsystem does not have to be a list of only one type 101 * of object; multiple ksets can belong to one subsystem. All 102 * ksets of a subsystem share the subsystem's lock. 103 * 104 * Each kset can support hotplugging; if it does, it will be given 105 * the opportunity to filter out specific kobjects from being 106 * reported, as well as to add its own "data" elements to the 107 * environment being passed to the hotplug helper. 108 */ 109struct kset_hotplug_ops { 110 int (*filter)(struct kset *kset, struct kobject *kobj); 111 const char *(*name)(struct kset *kset, struct kobject *kobj); 112 int (*hotplug)(struct kset *kset, struct kobject *kobj, char **envp, 113 int num_envp, char *buffer, int buffer_size); 114}; 115 116struct kset { 117 struct subsystem * subsys; 118 struct kobj_type * ktype; 119 struct list_head list; 120 spinlock_t list_lock; 121 struct kobject kobj; 122 struct kset_hotplug_ops * hotplug_ops; 123}; 124 125 126extern void kset_init(struct kset * k); 127extern int kset_add(struct kset * k); 128extern int kset_register(struct kset * k); 129extern void kset_unregister(struct kset * k); 130 131static inline struct kset * to_kset(struct kobject * kobj) 132{ 133 return kobj ? container_of(kobj,struct kset,kobj) : NULL; 134} 135 136static inline struct kset * kset_get(struct kset * k) 137{ 138 return k ? to_kset(kobject_get(&k->kobj)) : NULL; 139} 140 141static inline void kset_put(struct kset * k) 142{ 143 kobject_put(&k->kobj); 144} 145 146static inline struct kobj_type * get_ktype(struct kobject * k) 147{ 148 if (k->kset && k->kset->ktype) 149 return k->kset->ktype; 150 else 151 return k->ktype; 152} 153 154extern struct kobject * kset_find_obj(struct kset *, const char *); 155 156 157/** 158 * Use this when initializing an embedded kset with no other 159 * fields to initialize. 160 */ 161#define set_kset_name(str) .kset = { .kobj = { .name = str } } 162 163 164 165struct subsystem { 166 struct kset kset; 167 struct rw_semaphore rwsem; 168}; 169 170#define decl_subsys(_name,_type,_hotplug_ops) \ 171struct subsystem _name##_subsys = { \ 172 .kset = { \ 173 .kobj = { .name = __stringify(_name) }, \ 174 .ktype = _type, \ 175 .hotplug_ops =_hotplug_ops, \ 176 } \ 177} 178#define decl_subsys_name(_varname,_name,_type,_hotplug_ops) \ 179struct subsystem _varname##_subsys = { \ 180 .kset = { \ 181 .kobj = { .name = __stringify(_name) }, \ 182 .ktype = _type, \ 183 .hotplug_ops =_hotplug_ops, \ 184 } \ 185} 186 187/* The global /sys/kernel/ subsystem for people to chain off of */ 188extern struct subsystem kernel_subsys; 189 190/** 191 * Helpers for setting the kset of registered objects. 192 * Often, a registered object belongs to a kset embedded in a 193 * subsystem. These do no magic, just make the resulting code 194 * easier to follow. 195 */ 196 197/** 198 * kobj_set_kset_s(obj,subsys) - set kset for embedded kobject. 199 * @obj: ptr to some object type. 200 * @subsys: a subsystem object (not a ptr). 201 * 202 * Can be used for any object type with an embedded ->kobj. 203 */ 204 205#define kobj_set_kset_s(obj,subsys) \ 206 (obj)->kobj.kset = &(subsys).kset 207 208/** 209 * kset_set_kset_s(obj,subsys) - set kset for embedded kset. 210 * @obj: ptr to some object type. 211 * @subsys: a subsystem object (not a ptr). 212 * 213 * Can be used for any object type with an embedded ->kset. 214 * Sets the kset of @obj's embedded kobject (via its embedded 215 * kset) to @subsys.kset. This makes @obj a member of that 216 * kset. 217 */ 218 219#define kset_set_kset_s(obj,subsys) \ 220 (obj)->kset.kobj.kset = &(subsys).kset 221 222/** 223 * subsys_set_kset(obj,subsys) - set kset for subsystem 224 * @obj: ptr to some object type. 225 * @subsys: a subsystem object (not a ptr). 226 * 227 * Can be used for any object type with an embedded ->subsys. 228 * Sets the kset of @obj's kobject to @subsys.kset. This makes 229 * the object a member of that kset. 230 */ 231 232#define subsys_set_kset(obj,_subsys) \ 233 (obj)->subsys.kset.kobj.kset = &(_subsys).kset 234 235extern void subsystem_init(struct subsystem *); 236extern int subsystem_register(struct subsystem *); 237extern void subsystem_unregister(struct subsystem *); 238 239static inline struct subsystem * subsys_get(struct subsystem * s) 240{ 241 return s ? container_of(kset_get(&s->kset),struct subsystem,kset) : NULL; 242} 243 244static inline void subsys_put(struct subsystem * s) 245{ 246 kset_put(&s->kset); 247} 248 249struct subsys_attribute { 250 struct attribute attr; 251 ssize_t (*show)(struct subsystem *, char *); 252 ssize_t (*store)(struct subsystem *, const char *, size_t); 253}; 254 255extern int subsys_create_file(struct subsystem * , struct subsys_attribute *); 256extern void subsys_remove_file(struct subsystem * , struct subsys_attribute *); 257 258#ifdef CONFIG_HOTPLUG 259void kobject_hotplug(struct kobject *kobj, enum kobject_action action); 260 261int add_hotplug_env_var(char **envp, int num_envp, int *cur_index, 262 char *buffer, int buffer_size, int *cur_len, 263 const char *format, ...) 264 __attribute__((format (printf, 7, 8))); 265#else 266static inline void kobject_hotplug(struct kobject *kobj, enum kobject_action action) { } 267 268static inline int add_hotplug_env_var(char **envp, int num_envp, int *cur_index, 269 char *buffer, int buffer_size, int *cur_len, 270 const char *format, ...) 271{ return 0; } 272#endif 273 274#endif /* __KERNEL__ */ 275#endif /* _KOBJECT_H_ */ 276