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         KOBJ_MOVE       = (__force kobject_action_t) 0x08,      /* device move */
  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 __must_check kobject_add(struct kobject *);
  77 extern void kobject_del(struct kobject *);
  78
  79 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
  80 extern int __must_check kobject_move(struct kobject *, struct kobject *);
  81
  82 extern int __must_check kobject_register(struct kobject *);
  83 extern void kobject_unregister(struct kobject *);
  84
  85 extern struct kobject * kobject_get(struct kobject *);
  86 extern void kobject_put(struct kobject *);
  87
  88 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
  89
  90 extern char * kobject_get_path(struct kobject *, gfp_t);
  91
  92 struct kobj_type {
  93         void (*release)(struct kobject *);
  94         struct sysfs_ops        * sysfs_ops;
  95         struct attribute        ** default_attrs;
  96 };
  97
  98
  99 /**
 100  *      kset - a set of kobjects of a specific type, belonging
 101  *      to a specific subsystem.
 102  *
 103  *      All kobjects of a kset should be embedded in an identical
 104  *      type. This type may have a descriptor, which the kset points
 105  *      to. This allows there to exist sets of objects of the same
 106  *      type in different subsystems.
 107  *
 108  *      A subsystem does not have to be a list of only one type
 109  *      of object; multiple ksets can belong to one subsystem. All
 110  *      ksets of a subsystem share the subsystem's lock.
 111  *
 112  *      Each kset can support specific event variables; it can
 113  *      supress the event generation or add subsystem specific
 114  *      variables carried with the event.
 115  */
 116 struct kset_uevent_ops {
 117         int (*filter)(struct kset *kset, struct kobject *kobj);
 118         const char *(*name)(struct kset *kset, struct kobject *kobj);
 119         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 120                         int num_envp, char *buffer, int buffer_size);
 121 };
 122
 123 struct kset {
 124         struct subsystem        * subsys;
 125         struct kobj_type        * ktype;
 126         struct list_head        list;
 127         spinlock_t              list_lock;
 128         struct kobject          kobj;
 129         struct kset_uevent_ops  * uevent_ops;
 130 };
 131
 132
 133 extern void kset_init(struct kset * k);
 134 extern int __must_check kset_add(struct kset * k);
 135 extern int __must_check kset_register(struct kset * k);
 136 extern void kset_unregister(struct kset * k);
 137
 138 static inline struct kset * to_kset(struct kobject * kobj)
 139 {
 140         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 141 }
 142
 143 static inline struct kset * kset_get(struct kset * k)
 144 {
 145         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 146 }
 147
 148 static inline void kset_put(struct kset * k)
 149 {
 150         kobject_put(&k->kobj);
 151 }
 152
 153 static inline struct kobj_type * get_ktype(struct kobject * k)
 154 {
 155         if (k->kset && k->kset->ktype)
 156                 return k->kset->ktype;
 157         else
 158                 return k->ktype;
 159 }
 160
 161 extern struct kobject * kset_find_obj(struct kset *, const char *);
 162
 163
 164 /**
 165  * Use this when initializing an embedded kset with no other
 166  * fields to initialize.
 167  */
 168 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 169
 170
 171
 172 struct subsystem {
 173         struct kset             kset;
 174         struct rw_semaphore     rwsem;
 175 };
 176
 177 #define decl_subsys(_name,_type,_uevent_ops) \
 178 struct subsystem _name##_subsys = { \
 179         .kset = { \
 180                 .kobj = { .name = __stringify(_name) }, \
 181                 .ktype = _type, \
 182                 .uevent_ops =_uevent_ops, \
 183         } \
 184 }
 185 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 186 struct subsystem _varname##_subsys = { \
 187         .kset = { \
 188                 .kobj = { .name = __stringify(_name) }, \
 189                 .ktype = _type, \
 190                 .uevent_ops =_uevent_ops, \
 191         } \
 192 }
 193
 194 /* The global /sys/kernel/ subsystem for people to chain off of */
 195 extern struct subsystem kernel_subsys;
 196 /* The global /sys/hypervisor/ subsystem  */
 197 extern struct subsystem hypervisor_subsys;
 198
 199 /**
 200  * Helpers for setting the kset of registered objects.
 201  * Often, a registered object belongs to a kset embedded in a
 202  * subsystem. These do no magic, just make the resulting code
 203  * easier to follow.
 204  */
 205
 206 /**
 207  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 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 ->kobj.
 212  */
 213
 214 #define kobj_set_kset_s(obj,subsys) \
 215         (obj)->kobj.kset = &(subsys).kset
 216
 217 /**
 218  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 219  *      @obj:           ptr to some object type.
 220  *      @subsys:        a subsystem object (not a ptr).
 221  *
 222  *      Can be used for any object type with an embedded ->kset.
 223  *      Sets the kset of @obj's  embedded kobject (via its embedded
 224  *      kset) to @subsys.kset. This makes @obj a member of that
 225  *      kset.
 226  */
 227
 228 #define kset_set_kset_s(obj,subsys) \
 229         (obj)->kset.kobj.kset = &(subsys).kset
 230
 231 /**
 232  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 233  *      @obj:           ptr to some object type.
 234  *      @subsys:        a subsystem object (not a ptr).
 235  *
 236  *      Can be used for any object type with an embedded ->subsys.
 237  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 238  *      the object a member of that kset.
 239  */
 240
 241 #define subsys_set_kset(obj,_subsys) \
 242         (obj)->subsys.kset.kobj.kset = &(_subsys).kset
 243
 244 extern void subsystem_init(struct subsystem *);
 245 extern int __must_check subsystem_register(struct subsystem *);
 246 extern void subsystem_unregister(struct subsystem *);
 247
 248 static inline struct subsystem * subsys_get(struct subsystem * s)
 249 {
 250         return s ? container_of(kset_get(&s->kset),struct subsystem,kset) : NULL;
 251 }
 252
 253 static inline void subsys_put(struct subsystem * s)
 254 {
 255         kset_put(&s->kset);
 256 }
 257
 258 struct subsys_attribute {
 259         struct attribute attr;
 260         ssize_t (*show)(struct subsystem *, char *);
 261         ssize_t (*store)(struct subsystem *, const char *, size_t);
 262 };
 263
 264 extern int __must_check subsys_create_file(struct subsystem * ,
 265                                         struct subsys_attribute *);
 266
 267 #if defined(CONFIG_HOTPLUG)
 268 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 269 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 270                         char *envp[]);
 271
 272 int add_uevent_var(char **envp, int num_envp, int *cur_index,
 273                         char *buffer, int buffer_size, int *cur_len,
 274                         const char *format, ...)
 275         __attribute__((format (printf, 7, 8)));
 276 #else
 277 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 278 { return 0; }
 279 static inline int kobject_uevent_env(struct kobject *kobj,
 280                                       enum kobject_action action,
 281                                       char *envp[])
 282 { return 0; }
 283
 284 static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,
 285                                       char *buffer, int buffer_size, int *cur_len,
 286                                       const char *format, ...)
 287 { return 0; }
 288 #endif
 289
 290 #endif /* __KERNEL__ */
 291 #endif /* _KOBJECT_H_ */