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_MOUNT      = (__force kobject_action_t) 0x04,      /* mount event for block devices (broken) */
  45         KOBJ_UMOUNT     = (__force kobject_action_t) 0x05,      /* umount event for block devices (broken) */
  46         KOBJ_OFFLINE    = (__force kobject_action_t) 0x06,      /* device offline */
  47         KOBJ_ONLINE     = (__force kobject_action_t) 0x07,      /* device online */
  48 };
  49
  50 struct kobject {
  51         const char              * k_name;
  52         char                    name[KOBJ_NAME_LEN];
  53         struct kref             kref;
  54         struct list_head        entry;
  55         struct kobject          * parent;
  56         struct kset             * kset;
  57         struct kobj_type        * ktype;
  58         struct dentry           * dentry;
  59 };
  60
  61 extern int kobject_set_name(struct kobject *, const char *, ...)
  62         __attribute__((format(printf,2,3)));
  63
  64 static inline const char * kobject_name(const struct kobject * kobj)
  65 {
  66         return kobj->k_name;
  67 }
  68
  69 extern void kobject_init(struct kobject *);
  70 extern void kobject_cleanup(struct kobject *);
  71
  72 extern int kobject_add(struct kobject *);
  73 extern void kobject_del(struct kobject *);
  74
  75 extern int kobject_rename(struct kobject *, const char *new_name);
  76
  77 extern int kobject_register(struct kobject *);
  78 extern void kobject_unregister(struct kobject *);
  79
  80 extern struct kobject * kobject_get(struct kobject *);
  81 extern void kobject_put(struct kobject *);
  82
  83 extern char * kobject_get_path(struct kobject *, gfp_t);
  84
  85 struct kobj_type {
  86         void (*release)(struct kobject *);
  87         struct sysfs_ops        * sysfs_ops;
  88         struct attribute        ** default_attrs;
  89 };
  90
  91
  92 /**
  93  *      kset - a set of kobjects of a specific type, belonging
  94  *      to a specific subsystem.
  95  *
  96  *      All kobjects of a kset should be embedded in an identical
  97  *      type. This type may have a descriptor, which the kset points
  98  *      to. This allows there to exist sets of objects of the same
  99  *      type in different subsystems.
 100  *
 101  *      A subsystem does not have to be a list of only one type
 102  *      of object; multiple ksets can belong to one subsystem. All
 103  *      ksets of a subsystem share the subsystem's lock.
 104  *
 105  *      Each kset can support specific event variables; it can
 106  *      supress the event generation or add subsystem specific
 107  *      variables carried with the event.
 108  */
 109 struct kset_uevent_ops {
 110         int (*filter)(struct kset *kset, struct kobject *kobj);
 111         const char *(*name)(struct kset *kset, struct kobject *kobj);
 112         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 113                         int num_envp, char *buffer, int buffer_size);
 114 };
 115
 116 struct 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_uevent_ops  * uevent_ops;
 123 };
 124
 125
 126 extern void kset_init(struct kset * k);
 127 extern int kset_add(struct kset * k);
 128 extern int kset_register(struct kset * k);
 129 extern void kset_unregister(struct kset * k);
 130
 131 static inline struct kset * to_kset(struct kobject * kobj)
 132 {
 133         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 134 }
 135
 136 static inline struct kset * kset_get(struct kset * k)
 137 {
 138         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 139 }
 140
 141 static inline void kset_put(struct kset * k)
 142 {
 143         kobject_put(&k->kobj);
 144 }
 145
 146 static 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
 154 extern 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
 165 struct subsystem {
 166         struct kset             kset;
 167         struct rw_semaphore     rwsem;
 168 };
 169
 170 #define decl_subsys(_name,_type,_uevent_ops) \
 171 struct subsystem _name##_subsys = { \
 172         .kset = { \
 173                 .kobj = { .name = __stringify(_name) }, \
 174                 .ktype = _type, \
 175                 .uevent_ops =_uevent_ops, \
 176         } \
 177 }
 178 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 179 struct subsystem _varname##_subsys = { \
 180         .kset = { \
 181                 .kobj = { .name = __stringify(_name) }, \
 182                 .ktype = _type, \
 183                 .uevent_ops =_uevent_ops, \
 184         } \
 185 }
 186
 187 /* The global /sys/kernel/ subsystem for people to chain off of */
 188 extern 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
 235 extern void subsystem_init(struct subsystem *);
 236 extern int subsystem_register(struct subsystem *);
 237 extern void subsystem_unregister(struct subsystem *);
 238
 239 static inline struct subsystem * subsys_get(struct subsystem * s)
 240 {
 241         return s ? container_of(kset_get(&s->kset),struct subsystem,kset) : NULL;
 242 }
 243
 244 static inline void subsys_put(struct subsystem * s)
 245 {
 246         kset_put(&s->kset);
 247 }
 248
 249 struct 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
 255 extern int subsys_create_file(struct subsystem * , struct subsys_attribute *);
 256 extern void subsys_remove_file(struct subsystem * , struct subsys_attribute *);
 257
 258 #if defined(CONFIG_HOTPLUG) & defined(CONFIG_NET)
 259 void kobject_uevent(struct kobject *kobj, enum kobject_action action);
 260
 261 int add_uevent_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
 266 static inline void kobject_uevent(struct kobject *kobj, enum kobject_action action) { }
 267
 268 static inline 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 { return 0; }
 272 #endif
 273
 274 #endif /* __KERNEL__ */
 275 #endif /* _KOBJECT_H_ */