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/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_OFFLINE    = (__force kobject_action_t) 0x04,      /* device offline */
  46         KOBJ_ONLINE     = (__force kobject_action_t) 0x05,      /* device online */
  47         KOBJ_MOVE       = (__force kobject_action_t) 0x06,      /* device move */
  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         wait_queue_head_t       poll;
  60 };
  61
  62 extern int kobject_set_name(struct kobject *, const char *, ...)
  63         __attribute__((format(printf,2,3)));
  64
  65 static inline const char * kobject_name(const struct kobject * kobj)
  66 {
  67         return kobj->k_name;
  68 }
  69
  70 extern void kobject_init(struct kobject *);
  71 extern void kobject_cleanup(struct kobject *);
  72
  73 extern int __must_check kobject_add(struct kobject *);
  74 extern int __must_check kobject_shadow_add(struct kobject *, struct dentry *);
  75 extern void kobject_del(struct kobject *);
  76
  77 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
  78 extern int __must_check kobject_shadow_rename(struct kobject *kobj,
  79                                                 struct dentry *new_parent,
  80                                                 const char *new_name);
  81 extern int __must_check kobject_move(struct kobject *, struct kobject *);
  82
  83 extern int __must_check kobject_register(struct kobject *);
  84 extern void kobject_unregister(struct kobject *);
  85
  86 extern struct kobject * kobject_get(struct kobject *);
  87 extern void kobject_put(struct kobject *);
  88
  89 extern struct kobject *kobject_kset_add_dir(struct kset *kset,
  90                                             struct kobject *, const char *);
  91 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
  92
  93 extern char * kobject_get_path(struct kobject *, gfp_t);
  94
  95 struct kobj_type {
  96         void (*release)(struct kobject *);
  97         struct sysfs_ops        * sysfs_ops;
  98         struct attribute        ** default_attrs;
  99 };
 100
 101
 102 /**
 103  *      kset - a set of kobjects of a specific type, belonging
 104  *      to a specific subsystem.
 105  *
 106  *      All kobjects of a kset should be embedded in an identical
 107  *      type. This type may have a descriptor, which the kset points
 108  *      to. This allows there to exist sets of objects of the same
 109  *      type in different subsystems.
 110  *
 111  *      A subsystem does not have to be a list of only one type
 112  *      of object; multiple ksets can belong to one subsystem. All
 113  *      ksets of a subsystem share the subsystem's lock.
 114  *
 115  *      Each kset can support specific event variables; it can
 116  *      supress the event generation or add subsystem specific
 117  *      variables carried with the event.
 118  */
 119 struct kset_uevent_ops {
 120         int (*filter)(struct kset *kset, struct kobject *kobj);
 121         const char *(*name)(struct kset *kset, struct kobject *kobj);
 122         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 123                         int num_envp, char *buffer, int buffer_size);
 124 };
 125
 126 struct kset {
 127         struct kobj_type        * ktype;
 128         struct list_head        list;
 129         spinlock_t              list_lock;
 130         struct kobject          kobj;
 131         struct kset_uevent_ops  * uevent_ops;
 132 };
 133
 134
 135 extern void kset_init(struct kset * k);
 136 extern int __must_check kset_add(struct kset * k);
 137 extern int __must_check kset_register(struct kset * k);
 138 extern void kset_unregister(struct kset * k);
 139
 140 static inline struct kset * to_kset(struct kobject * kobj)
 141 {
 142         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 143 }
 144
 145 static inline struct kset * kset_get(struct kset * k)
 146 {
 147         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 148 }
 149
 150 static inline void kset_put(struct kset * k)
 151 {
 152         kobject_put(&k->kobj);
 153 }
 154
 155 static inline struct kobj_type * get_ktype(struct kobject * k)
 156 {
 157         if (k->kset && k->kset->ktype)
 158                 return k->kset->ktype;
 159         else
 160                 return k->ktype;
 161 }
 162
 163 extern struct kobject * kset_find_obj(struct kset *, const char *);
 164
 165
 166 /**
 167  * Use this when initializing an embedded kset with no other
 168  * fields to initialize.
 169  */
 170 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 171
 172
 173 #define decl_subsys(_name,_type,_uevent_ops) \
 174 struct kset _name##_subsys = { \
 175         .kobj = { .name = __stringify(_name) }, \
 176         .ktype = _type, \
 177         .uevent_ops =_uevent_ops, \
 178 }
 179 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 180 struct kset _varname##_subsys = { \
 181         .kobj = { .name = __stringify(_name) }, \
 182         .ktype = _type, \
 183         .uevent_ops =_uevent_ops, \
 184 }
 185
 186 /* The global /sys/kernel/ subsystem for people to chain off of */
 187 extern struct kset kernel_subsys;
 188 /* The global /sys/hypervisor/ subsystem  */
 189 extern struct kset hypervisor_subsys;
 190
 191 /**
 192  * Helpers for setting the kset of registered objects.
 193  * Often, a registered object belongs to a kset embedded in a
 194  * subsystem. These do no magic, just make the resulting code
 195  * easier to follow.
 196  */
 197
 198 /**
 199  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 200  *      @obj:           ptr to some object type.
 201  *      @subsys:        a subsystem object (not a ptr).
 202  *
 203  *      Can be used for any object type with an embedded ->kobj.
 204  */
 205
 206 #define kobj_set_kset_s(obj,subsys) \
 207         (obj)->kobj.kset = &(subsys)
 208
 209 /**
 210  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 211  *      @obj:           ptr to some object type.
 212  *      @subsys:        a subsystem object (not a ptr).
 213  *
 214  *      Can be used for any object type with an embedded ->kset.
 215  *      Sets the kset of @obj's  embedded kobject (via its embedded
 216  *      kset) to @subsys.kset. This makes @obj a member of that
 217  *      kset.
 218  */
 219
 220 #define kset_set_kset_s(obj,subsys) \
 221         (obj)->kset.kobj.kset = &(subsys)
 222
 223 /**
 224  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 225  *      @obj:           ptr to some object type.
 226  *      @subsys:        a subsystem object (not a ptr).
 227  *
 228  *      Can be used for any object type with an embedded ->subsys.
 229  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 230  *      the object a member of that kset.
 231  */
 232
 233 #define subsys_set_kset(obj,_subsys) \
 234         (obj)->subsys.kobj.kset = &(_subsys)
 235
 236 extern void subsystem_init(struct kset *);
 237 extern int __must_check subsystem_register(struct kset *);
 238 extern void subsystem_unregister(struct kset *);
 239
 240 static inline struct kset *subsys_get(struct kset *s)
 241 {
 242         if (s)
 243                 return kset_get(s);
 244         return NULL;
 245 }
 246
 247 static inline void subsys_put(struct kset *s)
 248 {
 249         kset_put(s);
 250 }
 251
 252 struct subsys_attribute {
 253         struct attribute attr;
 254         ssize_t (*show)(struct kset *, char *);
 255         ssize_t (*store)(struct kset *, const char *, size_t);
 256 };
 257
 258 extern int __must_check subsys_create_file(struct kset *,
 259                                         struct subsys_attribute *);
 260
 261 #if defined(CONFIG_HOTPLUG)
 262 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 263 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 264                         char *envp[]);
 265
 266 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         __attribute__((format (printf, 7, 8)));
 270 #else
 271 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 272 { return 0; }
 273 static inline int kobject_uevent_env(struct kobject *kobj,
 274                                       enum kobject_action action,
 275                                       char *envp[])
 276 { return 0; }
 277
 278 static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,
 279                                       char *buffer, int buffer_size, int *cur_len,
 280                                       const char *format, ...)
 281 { return 0; }
 282 #endif
 283
 284 #endif /* __KERNEL__ */
 285 #endif /* _KOBJECT_H_ */