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 <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 */
  34 extern char hotplug_path[];
  35
  36 /* counter to tag the hotplug event, read only except for the kobject core */
  37 extern u64 hotplug_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,      /* add event, for hotplug */
  43         KOBJ_REMOVE     = (__force kobject_action_t) 0x02,      /* remove event, for hotplug */
  44         KOBJ_CHANGE     = (__force kobject_action_t) 0x03,      /* a sysfs attribute file has changed */
  45         KOBJ_MOUNT      = (__force kobject_action_t) 0x04,      /* mount event for block devices */
  46         KOBJ_UMOUNT     = (__force kobject_action_t) 0x05,      /* umount event for block devices */
  47         KOBJ_OFFLINE    = (__force kobject_action_t) 0x06,      /* offline event for hotplug devices */
  48         KOBJ_ONLINE     = (__force kobject_action_t) 0x07,      /* online event for hotplug devices */
  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 };
  61
  62 extern int kobject_set_name(struct kobject *, const char *, ...)
  63         __attribute__((format(printf,2,3)));
  64
  65 static inline const char * kobject_name(const struct kobject * kobj)
  66 {
  67         return kobj->k_name;
  68 }
  69
  70 extern void kobject_init(struct kobject *);
  71 extern void kobject_cleanup(struct kobject *);
  72
  73 extern int kobject_add(struct kobject *);
  74 extern void kobject_del(struct kobject *);
  75
  76 extern int kobject_rename(struct kobject *, const char *new_name);
  77
  78 extern int kobject_register(struct kobject *);
  79 extern void kobject_unregister(struct kobject *);
  80
  81 extern struct kobject * kobject_get(struct kobject *);
  82 extern void kobject_put(struct kobject *);
  83
  84 extern char * kobject_get_path(struct kobject *, gfp_t);
  85
  86 struct kobj_type {
  87         void (*release)(struct kobject *);
  88         struct sysfs_ops        * sysfs_ops;
  89         struct attribute        ** default_attrs;
  90 };
  91
  92
  93 /**
  94  *      kset - a set of kobjects of a specific type, belonging
  95  *      to a specific subsystem.
  96  *
  97  *      All kobjects of a kset should be embedded in an identical
  98  *      type. This type may have a descriptor, which the kset points
  99  *      to. This allows there to exist sets of objects of the same
 100  *      type in different subsystems.
 101  *
 102  *      A subsystem does not have to be a list of only one type
 103  *      of object; multiple ksets can belong to one subsystem. All
 104  *      ksets of a subsystem share the subsystem's lock.
 105  *
 106  *      Each kset can support hotplugging; if it does, it will be given
 107  *      the opportunity to filter out specific kobjects from being
 108  *      reported, as well as to add its own "data" elements to the
 109  *      environment being passed to the hotplug helper.
 110  */
 111 struct kset_hotplug_ops {
 112         int (*filter)(struct kset *kset, struct kobject *kobj);
 113         const char *(*name)(struct kset *kset, struct kobject *kobj);
 114         int (*hotplug)(struct kset *kset, struct kobject *kobj, char **envp,
 115                         int num_envp, char *buffer, int buffer_size);
 116 };
 117
 118 struct kset {
 119         struct subsystem        * subsys;
 120         struct kobj_type        * ktype;
 121         struct list_head        list;
 122         spinlock_t              list_lock;
 123         struct kobject          kobj;
 124         struct kset_hotplug_ops * hotplug_ops;
 125 };
 126
 127
 128 extern void kset_init(struct kset * k);
 129 extern int kset_add(struct kset * k);
 130 extern int kset_register(struct kset * k);
 131 extern void kset_unregister(struct kset * k);
 132
 133 static inline struct kset * to_kset(struct kobject * kobj)
 134 {
 135         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 136 }
 137
 138 static inline struct kset * kset_get(struct kset * k)
 139 {
 140         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 141 }
 142
 143 static inline void kset_put(struct kset * k)
 144 {
 145         kobject_put(&k->kobj);
 146 }
 147
 148 static inline struct kobj_type * get_ktype(struct kobject * k)
 149 {
 150         if (k->kset && k->kset->ktype)
 151                 return k->kset->ktype;
 152         else
 153                 return k->ktype;
 154 }
 155
 156 extern struct kobject * kset_find_obj(struct kset *, const char *);
 157
 158
 159 /**
 160  * Use this when initializing an embedded kset with no other
 161  * fields to initialize.
 162  */
 163 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 164
 165
 166
 167 struct subsystem {
 168         struct kset             kset;
 169         struct rw_semaphore     rwsem;
 170 };
 171
 172 #define decl_subsys(_name,_type,_hotplug_ops) \
 173 struct subsystem _name##_subsys = { \
 174         .kset = { \
 175                 .kobj = { .name = __stringify(_name) }, \
 176                 .ktype = _type, \
 177                 .hotplug_ops =_hotplug_ops, \
 178         } \
 179 }
 180 #define decl_subsys_name(_varname,_name,_type,_hotplug_ops) \
 181 struct subsystem _varname##_subsys = { \
 182         .kset = { \
 183                 .kobj = { .name = __stringify(_name) }, \
 184                 .ktype = _type, \
 185                 .hotplug_ops =_hotplug_ops, \
 186         } \
 187 }
 188
 189 /* The global /sys/kernel/ subsystem for people to chain off of */
 190 extern struct subsystem kernel_subsys;
 191
 192 /**
 193  * Helpers for setting the kset of registered objects.
 194  * Often, a registered object belongs to a kset embedded in a
 195  * subsystem. These do no magic, just make the resulting code
 196  * easier to follow.
 197  */
 198
 199 /**
 200  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 201  *      @obj:           ptr to some object type.
 202  *      @subsys:        a subsystem object (not a ptr).
 203  *
 204  *      Can be used for any object type with an embedded ->kobj.
 205  */
 206
 207 #define kobj_set_kset_s(obj,subsys) \
 208         (obj)->kobj.kset = &(subsys).kset
 209
 210 /**
 211  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 212  *      @obj:           ptr to some object type.
 213  *      @subsys:        a subsystem object (not a ptr).
 214  *
 215  *      Can be used for any object type with an embedded ->kset.
 216  *      Sets the kset of @obj's  embedded kobject (via its embedded
 217  *      kset) to @subsys.kset. This makes @obj a member of that
 218  *      kset.
 219  */
 220
 221 #define kset_set_kset_s(obj,subsys) \
 222         (obj)->kset.kobj.kset = &(subsys).kset
 223
 224 /**
 225  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 226  *      @obj:           ptr to some object type.
 227  *      @subsys:        a subsystem object (not a ptr).
 228  *
 229  *      Can be used for any object type with an embedded ->subsys.
 230  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 231  *      the object a member of that kset.
 232  */
 233
 234 #define subsys_set_kset(obj,_subsys) \
 235         (obj)->subsys.kset.kobj.kset = &(_subsys).kset
 236
 237 extern void subsystem_init(struct subsystem *);
 238 extern int subsystem_register(struct subsystem *);
 239 extern void subsystem_unregister(struct subsystem *);
 240
 241 static inline struct subsystem * subsys_get(struct subsystem * s)
 242 {
 243         return s ? container_of(kset_get(&s->kset),struct subsystem,kset) : NULL;
 244 }
 245
 246 static inline void subsys_put(struct subsystem * s)
 247 {
 248         kset_put(&s->kset);
 249 }
 250
 251 struct subsys_attribute {
 252         struct attribute attr;
 253         ssize_t (*show)(struct subsystem *, char *);
 254         ssize_t (*store)(struct subsystem *, const char *, size_t);
 255 };
 256
 257 extern int subsys_create_file(struct subsystem * , struct subsys_attribute *);
 258 extern void subsys_remove_file(struct subsystem * , struct subsys_attribute *);
 259
 260 #ifdef CONFIG_HOTPLUG
 261 void kobject_hotplug(struct kobject *kobj, enum kobject_action action);
 262
 263 int add_hotplug_env_var(char **envp, int num_envp, int *cur_index,
 264                         char *buffer, int buffer_size, int *cur_len,
 265                         const char *format, ...)
 266         __attribute__((format (printf, 7, 8)));
 267
 268 int kobject_uevent(struct kobject *kobj,
 269                    enum kobject_action action,
 270                    struct attribute *attr);
 271 int kobject_uevent_atomic(struct kobject *kobj,
 272                           enum kobject_action action,
 273                           struct attribute *attr);
 274
 275 #else
 276 static inline void kobject_hotplug(struct kobject *kobj, enum kobject_action action) { }
 277 static inline int add_hotplug_env_var(char **envp, int num_envp, int *cur_index,
 278                                       char *buffer, int buffer_size, int *cur_len,
 279                                       const char *format, ...)
 280 { return 0; }
 281 int kobject_uevent(struct kobject *kobj,
 282                    enum kobject_action action,
 283                    struct attribute *attr)
 284 { return 0; }
 285 int kobject_uevent_atomic(struct kobject *kobj,
 286                           enum kobject_action action,
 287                           struct attribute *attr)
 288 { return 0; }
 289 #endif
 290
 291 #endif /* __KERNEL__ */
 292 #endif /* _KOBJECT_H_ */