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 #define UEVENT_NUM_ENVP                 32      /* number of env pointers */
  33 #define UEVENT_BUFFER_SIZE              2048    /* buffer for the variables */
  34
  35 /* path to the userspace helper executed on an event */
  36 extern char uevent_helper[];
  37
  38 /* counter to tag the uevent, read only except for the kobject core */
  39 extern u64 uevent_seqnum;
  40
  41 /*
  42  * The actions here must match the index to the string array
  43  * in lib/kobject_uevent.c
  44  *
  45  * Do not add new actions here without checking with the driver-core
  46  * maintainers. Action strings are not meant to express subsystem
  47  * or device specific properties. In most cases you want to send a
  48  * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
  49  * specific variables added to the event environment.
  50  */
  51 enum kobject_action {
  52         KOBJ_ADD,
  53         KOBJ_REMOVE,
  54         KOBJ_CHANGE,
  55         KOBJ_MOVE,
  56         KOBJ_ONLINE,
  57         KOBJ_OFFLINE,
  58         KOBJ_MAX
  59 };
  60
  61 /* The list of strings defining the valid kobject actions as specified above */
  62 extern const char *kobject_actions[];
  63
  64 struct kobject {
  65         const char              * k_name;
  66         char                    name[KOBJ_NAME_LEN];
  67         struct kref             kref;
  68         struct list_head        entry;
  69         struct kobject          * parent;
  70         struct kset             * kset;
  71         struct kobj_type        * ktype;
  72         struct sysfs_dirent     * sd;
  73         wait_queue_head_t       poll;
  74 };
  75
  76 extern int kobject_set_name(struct kobject *, const char *, ...)
  77         __attribute__((format(printf,2,3)));
  78
  79 static inline const char * kobject_name(const struct kobject * kobj)
  80 {
  81         return kobj->k_name;
  82 }
  83
  84 extern void kobject_init(struct kobject *);
  85 extern void kobject_cleanup(struct kobject *);
  86
  87 extern int __must_check kobject_add(struct kobject *);
  88 extern int __must_check kobject_shadow_add(struct kobject *kobj,
  89                                            struct sysfs_dirent *shadow_parent);
  90 extern void kobject_del(struct kobject *);
  91
  92 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
  93 extern int __must_check kobject_shadow_rename(struct kobject *kobj,
  94                                               struct sysfs_dirent *new_parent,
  95                                               const char *new_name);
  96 extern int __must_check kobject_move(struct kobject *, struct kobject *);
  97
  98 extern int __must_check kobject_register(struct kobject *);
  99 extern void kobject_unregister(struct kobject *);
 100
 101 extern struct kobject * kobject_get(struct kobject *);
 102 extern void kobject_put(struct kobject *);
 103
 104 extern struct kobject *kobject_kset_add_dir(struct kset *kset,
 105                                             struct kobject *, const char *);
 106 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
 107
 108 extern char * kobject_get_path(struct kobject *, gfp_t);
 109
 110 struct kobj_type {
 111         void (*release)(struct kobject *);
 112         struct sysfs_ops        * sysfs_ops;
 113         struct attribute        ** default_attrs;
 114 };
 115
 116 struct kobj_uevent_env {
 117         char *envp[UEVENT_NUM_ENVP];
 118         int envp_idx;
 119         char buf[UEVENT_BUFFER_SIZE];
 120         int buflen;
 121 };
 122
 123 struct kset_uevent_ops {
 124         int (*filter)(struct kset *kset, struct kobject *kobj);
 125         const char *(*name)(struct kset *kset, struct kobject *kobj);
 126         int (*uevent)(struct kset *kset, struct kobject *kobj,
 127                       struct kobj_uevent_env *env);
 128 };
 129
 130 /*
 131  *      struct kset - a set of kobjects of a specific type, belonging
 132  *      to a specific subsystem.
 133  *
 134  *      All kobjects of a kset should be embedded in an identical
 135  *      type. This type may have a descriptor, which the kset points
 136  *      to. This allows there to exist sets of objects of the same
 137  *      type in different subsystems.
 138  *
 139  *      A subsystem does not have to be a list of only one type
 140  *      of object; multiple ksets can belong to one subsystem. All
 141  *      ksets of a subsystem share the subsystem's lock.
 142  *
 143  *      Each kset can support specific event variables; it can
 144  *      supress the event generation or add subsystem specific
 145  *      variables carried with the event.
 146  */
 147 struct kset {
 148         struct kobj_type        * ktype;
 149         struct list_head        list;
 150         spinlock_t              list_lock;
 151         struct kobject          kobj;
 152         struct kset_uevent_ops  * uevent_ops;
 153 };
 154
 155
 156 extern void kset_init(struct kset * k);
 157 extern int __must_check kset_add(struct kset * k);
 158 extern int __must_check kset_register(struct kset * k);
 159 extern void kset_unregister(struct kset * k);
 160
 161 static inline struct kset * to_kset(struct kobject * kobj)
 162 {
 163         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 164 }
 165
 166 static inline struct kset * kset_get(struct kset * k)
 167 {
 168         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 169 }
 170
 171 static inline void kset_put(struct kset * k)
 172 {
 173         kobject_put(&k->kobj);
 174 }
 175
 176 static inline struct kobj_type * get_ktype(struct kobject * k)
 177 {
 178         if (k->kset && k->kset->ktype)
 179                 return k->kset->ktype;
 180         else
 181                 return k->ktype;
 182 }
 183
 184 extern struct kobject * kset_find_obj(struct kset *, const char *);
 185
 186
 187 /*
 188  * Use this when initializing an embedded kset with no other
 189  * fields to initialize.
 190  */
 191 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 192
 193
 194 #define decl_subsys(_name,_type,_uevent_ops) \
 195 struct kset _name##_subsys = { \
 196         .kobj = { .name = __stringify(_name) }, \
 197         .ktype = _type, \
 198         .uevent_ops =_uevent_ops, \
 199 }
 200 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 201 struct kset _varname##_subsys = { \
 202         .kobj = { .name = __stringify(_name) }, \
 203         .ktype = _type, \
 204         .uevent_ops =_uevent_ops, \
 205 }
 206
 207 /* The global /sys/kernel/ subsystem for people to chain off of */
 208 extern struct kset kernel_subsys;
 209 /* The global /sys/hypervisor/ subsystem  */
 210 extern struct kset hypervisor_subsys;
 211
 212 /*
 213  * Helpers for setting the kset of registered objects.
 214  * Often, a registered object belongs to a kset embedded in a
 215  * subsystem. These do no magic, just make the resulting code
 216  * easier to follow.
 217  */
 218
 219 /**
 220  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 221  *      @obj:           ptr to some object type.
 222  *      @subsys:        a subsystem object (not a ptr).
 223  *
 224  *      Can be used for any object type with an embedded ->kobj.
 225  */
 226
 227 #define kobj_set_kset_s(obj,subsys) \
 228         (obj)->kobj.kset = &(subsys)
 229
 230 /**
 231  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 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 ->kset.
 236  *      Sets the kset of @obj's  embedded kobject (via its embedded
 237  *      kset) to @subsys.kset. This makes @obj a member of that
 238  *      kset.
 239  */
 240
 241 #define kset_set_kset_s(obj,subsys) \
 242         (obj)->kset.kobj.kset = &(subsys)
 243
 244 extern void subsystem_init(struct kset *);
 245 extern int __must_check subsystem_register(struct kset *);
 246 extern void subsystem_unregister(struct kset *);
 247
 248 static inline struct kset *subsys_get(struct kset *s)
 249 {
 250         if (s)
 251                 return kset_get(s);
 252         return NULL;
 253 }
 254
 255 static inline void subsys_put(struct kset *s)
 256 {
 257         kset_put(s);
 258 }
 259
 260 struct subsys_attribute {
 261         struct attribute attr;
 262         ssize_t (*show)(struct kset *, char *);
 263         ssize_t (*store)(struct kset *, const char *, size_t);
 264 };
 265
 266 extern int __must_check subsys_create_file(struct kset *,
 267                                         struct subsys_attribute *);
 268
 269 #if defined(CONFIG_HOTPLUG)
 270 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 271 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 272                         char *envp[]);
 273
 274 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 275         __attribute__((format (printf, 2, 3)));
 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(struct kobj_uevent_env *env, const char *format, ...)
 285 { return 0; }
 286 #endif
 287
 288 #endif /* __KERNEL__ */
 289 #endif /* _KOBJECT_H_ */