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         KOBJ_UNDOCK     = (__force kobject_action_t) 0x08,      /* undocking */
  50         KOBJ_DOCK       = (__force kobject_action_t) 0x09,      /* dock */
  51 };
  52
  53 struct kobject {
  54         const char              * k_name;
  55         char                    name[KOBJ_NAME_LEN];
  56         struct kref             kref;
  57         struct list_head        entry;
  58         struct kobject          * parent;
  59         struct kset             * kset;
  60         struct kobj_type        * ktype;
  61         struct dentry           * dentry;
  62         wait_queue_head_t       poll;
  63 };
  64
  65 extern int kobject_set_name(struct kobject *, const char *, ...)
  66         __attribute__((format(printf,2,3)));
  67
  68 static inline const char * kobject_name(const struct kobject * kobj)
  69 {
  70         return kobj->k_name;
  71 }
  72
  73 extern void kobject_init(struct kobject *);
  74 extern void kobject_cleanup(struct kobject *);
  75
  76 extern int kobject_add(struct kobject *);
  77 extern void kobject_del(struct kobject *);
  78
  79 extern int kobject_rename(struct kobject *, const char *new_name);
  80
  81 extern int kobject_register(struct kobject *);
  82 extern void kobject_unregister(struct kobject *);
  83
  84 extern struct kobject * kobject_get(struct kobject *);
  85 extern void kobject_put(struct kobject *);
  86
  87 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
  88
  89 extern char * kobject_get_path(struct kobject *, gfp_t);
  90
  91 struct kobj_type {
  92         void (*release)(struct kobject *);
  93         struct sysfs_ops        * sysfs_ops;
  94         struct attribute        ** default_attrs;
  95 };
  96
  97
  98 /**
  99  *      kset - a set of kobjects of a specific type, belonging
 100  *      to a specific subsystem.
 101  *
 102  *      All kobjects of a kset should be embedded in an identical
 103  *      type. This type may have a descriptor, which the kset points
 104  *      to. This allows there to exist sets of objects of the same
 105  *      type in different subsystems.
 106  *
 107  *      A subsystem does not have to be a list of only one type
 108  *      of object; multiple ksets can belong to one subsystem. All
 109  *      ksets of a subsystem share the subsystem's lock.
 110  *
 111  *      Each kset can support specific event variables; it can
 112  *      supress the event generation or add subsystem specific
 113  *      variables carried with the event.
 114  */
 115 struct kset_uevent_ops {
 116         int (*filter)(struct kset *kset, struct kobject *kobj);
 117         const char *(*name)(struct kset *kset, struct kobject *kobj);
 118         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 119                         int num_envp, char *buffer, int buffer_size);
 120 };
 121
 122 struct kset {
 123         struct subsystem        * subsys;
 124         struct kobj_type        * ktype;
 125         struct list_head        list;
 126         spinlock_t              list_lock;
 127         struct kobject          kobj;
 128         struct kset_uevent_ops  * uevent_ops;
 129 };
 130
 131
 132 extern void kset_init(struct kset * k);
 133 extern int kset_add(struct kset * k);
 134 extern int kset_register(struct kset * k);
 135 extern void kset_unregister(struct kset * k);
 136
 137 static inline struct kset * to_kset(struct kobject * kobj)
 138 {
 139         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 140 }
 141
 142 static inline struct kset * kset_get(struct kset * k)
 143 {
 144         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 145 }
 146
 147 static inline void kset_put(struct kset * k)
 148 {
 149         kobject_put(&k->kobj);
 150 }
 151
 152 static inline struct kobj_type * get_ktype(struct kobject * k)
 153 {
 154         if (k->kset && k->kset->ktype)
 155                 return k->kset->ktype;
 156         else
 157                 return k->ktype;
 158 }
 159
 160 extern struct kobject * kset_find_obj(struct kset *, const char *);
 161
 162
 163 /**
 164  * Use this when initializing an embedded kset with no other
 165  * fields to initialize.
 166  */
 167 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 168
 169
 170
 171 struct subsystem {
 172         struct kset             kset;
 173         struct rw_semaphore     rwsem;
 174 };
 175
 176 #define decl_subsys(_name,_type,_uevent_ops) \
 177 struct subsystem _name##_subsys = { \
 178         .kset = { \
 179                 .kobj = { .name = __stringify(_name) }, \
 180                 .ktype = _type, \
 181                 .uevent_ops =_uevent_ops, \
 182         } \
 183 }
 184 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 185 struct subsystem _varname##_subsys = { \
 186         .kset = { \
 187                 .kobj = { .name = __stringify(_name) }, \
 188                 .ktype = _type, \
 189                 .uevent_ops =_uevent_ops, \
 190         } \
 191 }
 192
 193 /* The global /sys/kernel/ subsystem for people to chain off of */
 194 extern struct subsystem kernel_subsys;
 195 /* The global /sys/hypervisor/ subsystem  */
 196 extern struct subsystem hypervisor_subsys;
 197
 198 /**
 199  * Helpers for setting the kset of registered objects.
 200  * Often, a registered object belongs to a kset embedded in a
 201  * subsystem. These do no magic, just make the resulting code
 202  * easier to follow.
 203  */
 204
 205 /**
 206  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 207  *      @obj:           ptr to some object type.
 208  *      @subsys:        a subsystem object (not a ptr).
 209  *
 210  *      Can be used for any object type with an embedded ->kobj.
 211  */
 212
 213 #define kobj_set_kset_s(obj,subsys) \
 214         (obj)->kobj.kset = &(subsys).kset
 215
 216 /**
 217  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 218  *      @obj:           ptr to some object type.
 219  *      @subsys:        a subsystem object (not a ptr).
 220  *
 221  *      Can be used for any object type with an embedded ->kset.
 222  *      Sets the kset of @obj's  embedded kobject (via its embedded
 223  *      kset) to @subsys.kset. This makes @obj a member of that
 224  *      kset.
 225  */
 226
 227 #define kset_set_kset_s(obj,subsys) \
 228         (obj)->kset.kobj.kset = &(subsys).kset
 229
 230 /**
 231  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 232  *      @obj:           ptr to some object type.
 233  *      @subsys:        a subsystem object (not a ptr).
 234  *
 235  *      Can be used for any object type with an embedded ->subsys.
 236  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 237  *      the object a member of that kset.
 238  */
 239
 240 #define subsys_set_kset(obj,_subsys) \
 241         (obj)->subsys.kset.kobj.kset = &(_subsys).kset
 242
 243 extern void subsystem_init(struct subsystem *);
 244 extern int subsystem_register(struct subsystem *);
 245 extern void subsystem_unregister(struct subsystem *);
 246
 247 static inline struct subsystem * subsys_get(struct subsystem * s)
 248 {
 249         return s ? container_of(kset_get(&s->kset),struct subsystem,kset) : NULL;
 250 }
 251
 252 static inline void subsys_put(struct subsystem * s)
 253 {
 254         kset_put(&s->kset);
 255 }
 256
 257 struct subsys_attribute {
 258         struct attribute attr;
 259         ssize_t (*show)(struct subsystem *, char *);
 260         ssize_t (*store)(struct subsystem *, const char *, size_t);
 261 };
 262
 263 extern int subsys_create_file(struct subsystem * , 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_ */