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