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/compiler.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/rwsem.h>
  26 #include <linux/kref.h>
  27 #include <linux/kernel.h>
  28 #include <linux/wait.h>
  29 #include <asm/atomic.h>
  30
  31 #define KOBJ_NAME_LEN                   20
  32 #define UEVENT_HELPER_PATH_LEN          256
  33
  34 /* path to the userspace helper executed on an event */
  35 extern char uevent_helper[];
  36
  37 /* counter to tag the uevent, read only except for the kobject core */
  38 extern u64 uevent_seqnum;
  39
  40 /* the actions here must match the proper string in lib/kobject_uevent.c */
  41 typedef int __bitwise kobject_action_t;
  42 enum kobject_action {
  43         KOBJ_ADD        = (__force kobject_action_t) 0x01,      /* exclusive to core */
  44         KOBJ_REMOVE     = (__force kobject_action_t) 0x02,      /* exclusive to core */
  45         KOBJ_CHANGE     = (__force kobject_action_t) 0x03,      /* device state change */
  46         KOBJ_MOUNT      = (__force kobject_action_t) 0x04,      /* mount event for block devices (broken) */
  47         KOBJ_UMOUNT     = (__force kobject_action_t) 0x05,      /* umount event for block devices (broken) */
  48         KOBJ_OFFLINE    = (__force kobject_action_t) 0x06,      /* device offline */
  49         KOBJ_ONLINE     = (__force kobject_action_t) 0x07,      /* device online */
  50 };
  51
  52 struct kobject {
  53         const char              * k_name;
  54         char                    name[KOBJ_NAME_LEN];
  55         struct kref             kref;
  56         struct list_head        entry;
  57         struct kobject          * parent;
  58         struct kset             * kset;
  59         struct kobj_type        * ktype;
  60         struct dentry           * dentry;
  61         wait_queue_head_t       poll;
  62 };
  63
  64 extern int kobject_set_name(struct kobject *, const char *, ...)
  65         __attribute__((format(printf,2,3)));
  66
  67 static inline const char * kobject_name(const struct kobject * kobj)
  68 {
  69         return kobj->k_name;
  70 }
  71
  72 extern void kobject_init(struct kobject *);
  73 extern void kobject_cleanup(struct kobject *);
  74
  75 extern int __must_check kobject_add(struct kobject *);
  76 extern void kobject_del(struct kobject *);
  77
  78 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
  79
  80 extern int __must_check kobject_register(struct kobject *);
  81 extern void kobject_unregister(struct kobject *);
  82
  83 extern struct kobject * kobject_get(struct kobject *);
  84 extern void kobject_put(struct kobject *);
  85
  86 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
  87
  88 extern char * kobject_get_path(struct kobject *, gfp_t);
  89
  90 struct kobj_type {
  91         void (*release)(struct kobject *);
  92         struct sysfs_ops        * sysfs_ops;
  93         struct attribute        ** default_attrs;
  94 };
  95
  96
  97 /**
  98  *      kset - a set of kobjects of a specific type, belonging
  99  *      to a specific subsystem.
 100  *
 101  *      All kobjects of a kset should be embedded in an identical
 102  *      type. This type may have a descriptor, which the kset points
 103  *      to. This allows there to exist sets of objects of the same
 104  *      type in different subsystems.
 105  *
 106  *      A subsystem does not have to be a list of only one type
 107  *      of object; multiple ksets can belong to one subsystem. All
 108  *      ksets of a subsystem share the subsystem's lock.
 109  *
 110  *      Each kset can support specific event variables; it can
 111  *      supress the event generation or add subsystem specific
 112  *      variables carried with the event.
 113  */
 114 struct kset_uevent_ops {
 115         int (*filter)(struct kset *kset, struct kobject *kobj);
 116         const char *(*name)(struct kset *kset, struct kobject *kobj);
 117         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 118                         int num_envp, char *buffer, int buffer_size);
 119 };
 120
 121 struct kset {
 122         struct subsystem        * subsys;
 123         struct kobj_type        * ktype;
 124         struct list_head        list;
 125         spinlock_t              list_lock;
 126         struct kobject          kobj;
 127         struct kset_uevent_ops  * uevent_ops;
 128 };
 129
 130
 131 extern void kset_init(struct kset * k);
 132 extern int __must_check kset_add(struct kset * k);
 133 extern int __must_check kset_register(struct kset * k);
 134 extern void kset_unregister(struct kset * k);
 135
 136 static inline struct kset * to_kset(struct kobject * kobj)
 137 {
 138         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 139 }
 140
 141 static inline struct kset * kset_get(struct kset * k)
 142 {
 143         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 144 }
 145
 146 static inline void kset_put(struct kset * k)
 147 {
 148         kobject_put(&k->kobj);
 149 }
 150
 151 static inline struct kobj_type * get_ktype(struct kobject * k)
 152 {
 153         if (k->kset && k->kset->ktype)
 154                 return k->kset->ktype;
 155         else
 156                 return k->ktype;
 157 }
 158
 159 extern struct kobject * kset_find_obj(struct kset *, const char *);
 160
 161
 162 /**
 163  * Use this when initializing an embedded kset with no other
 164  * fields to initialize.
 165  */
 166 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 167
 168
 169
 170 struct subsystem {
 171         struct kset             kset;
 172         struct rw_semaphore     rwsem;
 173 };
 174
 175 #define decl_subsys(_name,_type,_uevent_ops) \
 176 struct subsystem _name##_subsys = { \
 177         .kset = { \
 178                 .kobj = { .name = __stringify(_name) }, \
 179                 .ktype = _type, \
 180                 .uevent_ops =_uevent_ops, \
 181         } \
 182 }
 183 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 184 struct subsystem _varname##_subsys = { \
 185         .kset = { \
 186                 .kobj = { .name = __stringify(_name) }, \
 187                 .ktype = _type, \
 188                 .uevent_ops =_uevent_ops, \
 189         } \
 190 }
 191
 192 /* The global /sys/kernel/ subsystem for people to chain off of */
 193 extern struct subsystem kernel_subsys;
 194 /* The global /sys/hypervisor/ subsystem  */
 195 extern struct subsystem hypervisor_subsys;
 196
 197 /**
 198  * Helpers for setting the kset of registered objects.
 199  * Often, a registered object belongs to a kset embedded in a
 200  * subsystem. These do no magic, just make the resulting code
 201  * easier to follow.
 202  */
 203
 204 /**
 205  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 206  *      @obj:           ptr to some object type.
 207  *      @subsys:        a subsystem object (not a ptr).
 208  *
 209  *      Can be used for any object type with an embedded ->kobj.
 210  */
 211
 212 #define kobj_set_kset_s(obj,subsys) \
 213         (obj)->kobj.kset = &(subsys).kset
 214
 215 /**
 216  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 217  *      @obj:           ptr to some object type.
 218  *      @subsys:        a subsystem object (not a ptr).
 219  *
 220  *      Can be used for any object type with an embedded ->kset.
 221  *      Sets the kset of @obj's  embedded kobject (via its embedded
 222  *      kset) to @subsys.kset. This makes @obj a member of that
 223  *      kset.
 224  */
 225
 226 #define kset_set_kset_s(obj,subsys) \
 227         (obj)->kset.kobj.kset = &(subsys).kset
 228
 229 /**
 230  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 231  *      @obj:           ptr to some object type.
 232  *      @subsys:        a subsystem object (not a ptr).
 233  *
 234  *      Can be used for any object type with an embedded ->subsys.
 235  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 236  *      the object a member of that kset.
 237  */
 238
 239 #define subsys_set_kset(obj,_subsys) \
 240         (obj)->subsys.kset.kobj.kset = &(_subsys).kset
 241
 242 extern void subsystem_init(struct subsystem *);
 243 extern int __must_check subsystem_register(struct subsystem *);
 244 extern void subsystem_unregister(struct subsystem *);
 245
 246 static inline struct subsystem * subsys_get(struct subsystem * s)
 247 {
 248         return s ? container_of(kset_get(&s->kset),struct subsystem,kset) : NULL;
 249 }
 250
 251 static inline void subsys_put(struct subsystem * s)
 252 {
 253         kset_put(&s->kset);
 254 }
 255
 256 struct subsys_attribute {
 257         struct attribute attr;
 258         ssize_t (*show)(struct subsystem *, char *);
 259         ssize_t (*store)(struct subsystem *, const char *, size_t);
 260 };
 261
 262 extern int __must_check subsys_create_file(struct subsystem * ,
 263                                         struct subsys_attribute *);
 264
 265 #if defined(CONFIG_HOTPLUG)
 266 void kobject_uevent(struct kobject *kobj, enum kobject_action action);
 267
 268 int add_uevent_var(char **envp, int num_envp, int *cur_index,
 269                         char *buffer, int buffer_size, int *cur_len,
 270                         const char *format, ...)
 271         __attribute__((format (printf, 7, 8)));
 272 #else
 273 static inline void kobject_uevent(struct kobject *kobj, enum kobject_action action) { }
 274
 275 static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,
 276                                       char *buffer, int buffer_size, int *cur_len,
 277                                       const char *format, ...)
 278 { return 0; }
 279 #endif
 280
 281 #endif /* __KERNEL__ */
 282 #endif /* _KOBJECT_H_ */