include/linux/kobject.h

   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 <linux/wait.h>
  28 #include <asm/atomic.h>
  29
  30 #define KOBJ_NAME_LEN                   20
  31 #define UEVENT_HELPER_PATH_LEN          256
  32
  33 /* path to the userspace helper executed on an event */
  34 extern char uevent_helper[];
  35
  36 /* counter to tag the uevent, read only except for the kobject core */
  37 extern u64 uevent_seqnum;
  38
  39 /* the actions here must match the proper string in lib/kobject_uevent.c */
  40 typedef int __bitwise kobject_action_t;
  41 enum 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_MOUNT      = (__force kobject_action_t) 0x04,      /* mount event for block devices (broken) */
  46         KOBJ_UMOUNT     = (__force kobject_action_t) 0x05,      /* umount event for block devices (broken) */
  47         KOBJ_OFFLINE    = (__force kobject_action_t) 0x06,      /* device offline */
  48         KOBJ_ONLINE     = (__force kobject_action_t) 0x07,      /* device online */
  49 };
  50
  51 struct kobject {
  52         const char              * k_name;
  53         char                    name[KOBJ_NAME_LEN];
  54         struct kref             kref;
  55         struct list_head        entry;
  56         struct kobject          * parent;
  57         struct kset             * kset;
  58         struct kobj_type        * ktype;
  59         struct dentry           * dentry;
  60         wait_queue_head_t       poll;
  61 };
  62
  63 extern int kobject_set_name(struct kobject *, const char *, ...)
  64         __attribute__((format(printf,2,3)));
  65
  66 static inline const char * kobject_name(const struct kobject * kobj)
  67 {
  68         return kobj->k_name;
  69 }
  70
  71 extern void kobject_init(struct kobject *);
  72 extern void kobject_cleanup(struct kobject *);
  73
  74 extern int kobject_add(struct kobject *);
  75 extern void kobject_del(struct kobject *);
  76
  77 extern int kobject_rename(struct kobject *, const char *new_name);
  78
  79 extern int kobject_register(struct kobject *);
  80 extern void kobject_unregister(struct kobject *);
  81
  82 extern struct kobject * kobject_get(struct kobject *);
  83 extern void kobject_put(struct kobject *);
  84
  85 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
  86
  87 extern char * kobject_get_path(struct kobject *, gfp_t);
  88
  89 struct kobj_type {
  90         void (*release)(struct kobject *);
  91         struct sysfs_ops        * sysfs_ops;
  92         struct attribute        ** default_attrs;
  93 };
  94
  95
  96 /**
  97  *      kset - a set of kobjects of a specific type, belonging
  98  *      to a specific subsystem.
  99  *
 100  *      All kobjects of a kset should be embedded in an identical
 101  *      type. This type may have a descriptor, which the kset points
 102  *      to. This allows there to exist sets of objects of the same
 103  *      type in different subsystems.
 104  *
 105  *      A subsystem does not have to be a list of only one type
 106  *      of object; multiple ksets can belong to one subsystem. All
 107  *      ksets of a subsystem share the subsystem's lock.
 108  *
 109  *      Each kset can support specific event variables; it can
 110  *      supress the event generation or add subsystem specific
 111  *      variables carried with the event.
 112  */
 113 struct kset_uevent_ops {
 114         int (*filter)(struct kset *kset, struct kobject *kobj);
 115         const char *(*name)(struct kset *kset, struct kobject *kobj);
 116         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 117                         int num_envp, char *buffer, int buffer_size);
 118 };
 119
 120 struct kset {
 121         struct subsystem        * subsys;
 122         struct kobj_type        * ktype;
 123         struct list_head        list;
 124         spinlock_t              list_lock;
 125         struct kobject          kobj;
 126         struct kset_uevent_ops  * uevent_ops;
 127 };
 128
 129
 130 extern void kset_init(struct kset * k);
 131 extern int kset_add(struct kset * k);
 132 extern int kset_register(struct kset * k);
 133 extern void kset_unregister(struct kset * k);
 134
 135 static inline struct kset * to_kset(struct kobject * kobj)
 136 {
 137         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 138 }
 139
 140 static inline struct kset * kset_get(struct kset * k)
 141 {
 142         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 143 }
 144
 145 static inline void kset_put(struct kset * k)
 146 {
 147         kobject_put(&k->kobj);
 148 }
 149
 150 static inline struct kobj_type * get_ktype(struct kobject * k)
 151 {
 152         if (k->kset && k->kset->ktype)
 153                 return k->kset->ktype;
 154         else
 155                 return k->ktype;
 156 }
 157
 158 extern struct kobject * kset_find_obj(struct kset *, const char *);
 159
 160
 161 /**
 162  * Use this when initializing an embedded kset with no other
 163  * fields to initialize.
 164  */
 165 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 166
 167
 168
 169 struct subsystem {
 170         struct kset             kset;
 171         struct rw_semaphore     rwsem;
 172 };
 173
 174 #define decl_subsys(_name,_type,_uevent_ops) \
 175 struct subsystem _name##_subsys = { \
 176         .kset = { \
 177                 .kobj = { .name = __stringify(_name) }, \
 178                 .ktype = _type, \
 179                 .uevent_ops =_uevent_ops, \
 180         } \
 181 }
 182 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 183 struct subsystem _varname##_subsys = { \
 184         .kset = { \
 185                 .kobj = { .name = __stringify(_name) }, \
 186                 .ktype = _type, \
 187                 .uevent_ops =_uevent_ops, \
 188         } \
 189 }
 190
 191 /* The global /sys/kernel/ subsystem for people to chain off of */
 192 extern struct subsystem kernel_subsys;
 193 /* The global /sys/hypervisor/ subsystem  */
 194 extern struct subsystem hypervisor_subsys;
 195
 196 /**
 197  * Helpers for setting the kset of registered objects.
 198  * Often, a registered object belongs to a kset embedded in a
 199  * subsystem. These do no magic, just make the resulting code
 200  * easier to follow.
 201  */
 202
 203 /**
 204  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 205  *      @obj:           ptr to some object type.
 206  *      @subsys:        a subsystem object (not a ptr).
 207  *
 208  *      Can be used for any object type with an embedded ->kobj.
 209  */
 210
 211 #define kobj_set_kset_s(obj,subsys) \
 212         (obj)->kobj.kset = &(subsys).kset
 213
 214 /**
 215  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 216  *      @obj:           ptr to some object type.
 217  *      @subsys:        a subsystem object (not a ptr).
 218  *
 219  *      Can be used for any object type with an embedded ->kset.
 220  *      Sets the kset of @obj's  embedded kobject (via its embedded
 221  *      kset) to @subsys.kset. This makes @obj a member of that
 222  *      kset.
 223  */
 224
 225 #define kset_set_kset_s(obj,subsys) \
 226         (obj)->kset.kobj.kset = &(subsys).kset
 227
 228 /**
 229  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 230  *      @obj:           ptr to some object type.
 231  *      @subsys:        a subsystem object (not a ptr).
 232  *
 233  *      Can be used for any object type with an embedded ->subsys.
 234  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 235  *      the object a member of that kset.
 236  */
 237
 238 #define subsys_set_kset(obj,_subsys) \
 239         (obj)->subsys.kset.kobj.kset = &(_subsys).kset
 240
 241 extern void subsystem_init(struct subsystem *);
 242 extern int subsystem_register(struct subsystem *);
 243 extern void subsystem_unregister(struct subsystem *);
 244
 245 static inline struct subsystem * subsys_get(struct subsystem * s)
 246 {
 247         return s ? container_of(kset_get(&s->kset),struct subsystem,kset) : NULL;
 248 }
 249
 250 static inline void subsys_put(struct subsystem * s)
 251 {
 252         kset_put(&s->kset);
 253 }
 254
 255 struct subsys_attribute {
 256         struct attribute attr;
 257         ssize_t (*show)(struct subsystem *, char *);
 258         ssize_t (*store)(struct subsystem *, const char *, size_t);
 259 };
 260
 261 extern int subsys_create_file(struct subsystem * , struct subsys_attribute *);
 262
 263 #if defined(CONFIG_HOTPLUG)
 264 void kobject_uevent(struct kobject *kobj, enum kobject_action action);
 265
 266 int add_uevent_var(char **envp, int num_envp, int *cur_index,
 267                         char *buffer, int buffer_size, int *cur_len,
 268                         const char *format, ...)
 269         __attribute__((format (printf, 7, 8)));
 270 #else
 271 static inline void kobject_uevent(struct kobject *kobj, enum kobject_action action) { }
 272
 273 static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,
 274                                       char *buffer, int buffer_size, int *cur_len,
 275                                       const char *format, ...)
 276 { return 0; }
 277 #endif
 278
 279 #endif /* __KERNEL__ */
 280 #endif /* _KOBJECT_H_ */