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 /*
  40  * The actions here must match the index to the string array
  41  * in lib/kobject_uevent.c
  42  *
  43  * Do not add new actions here without checking with the driver-core
  44  * maintainers. Action strings are not meant to express subsystem
  45  * or device specific properties. In most cases you want to send a
  46  * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
  47  * specific variables added to the event environment.
  48  */
  49 enum kobject_action {
  50         KOBJ_ADD,
  51         KOBJ_REMOVE,
  52         KOBJ_CHANGE,
  53         KOBJ_MOVE,
  54         KOBJ_ONLINE,
  55         KOBJ_OFFLINE,
  56         KOBJ_MAX
  57 };
  58
  59 struct kobject {
  60         const char              * k_name;
  61         char                    name[KOBJ_NAME_LEN];
  62         struct kref             kref;
  63         struct list_head        entry;
  64         struct kobject          * parent;
  65         struct kset             * kset;
  66         struct kobj_type        * ktype;
  67         struct sysfs_dirent     * sd;
  68         wait_queue_head_t       poll;
  69 };
  70
  71 extern int kobject_set_name(struct kobject *, const char *, ...)
  72         __attribute__((format(printf,2,3)));
  73
  74 static inline const char * kobject_name(const struct kobject * kobj)
  75 {
  76         return kobj->k_name;
  77 }
  78
  79 extern void kobject_init(struct kobject *);
  80 extern void kobject_cleanup(struct kobject *);
  81
  82 extern int __must_check kobject_add(struct kobject *);
  83 extern int __must_check kobject_shadow_add(struct kobject *kobj,
  84                                            struct sysfs_dirent *shadow_parent);
  85 extern void kobject_del(struct kobject *);
  86
  87 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
  88 extern int __must_check kobject_shadow_rename(struct kobject *kobj,
  89                                               struct sysfs_dirent *new_parent,
  90                                               const char *new_name);
  91 extern int __must_check kobject_move(struct kobject *, struct kobject *);
  92
  93 extern int __must_check kobject_register(struct kobject *);
  94 extern void kobject_unregister(struct kobject *);
  95
  96 extern struct kobject * kobject_get(struct kobject *);
  97 extern void kobject_put(struct kobject *);
  98
  99 extern struct kobject *kobject_kset_add_dir(struct kset *kset,
 100                                             struct kobject *, const char *);
 101 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
 102
 103 extern char * kobject_get_path(struct kobject *, gfp_t);
 104
 105 struct kobj_type {
 106         void (*release)(struct kobject *);
 107         struct sysfs_ops        * sysfs_ops;
 108         struct attribute        ** default_attrs;
 109 };
 110
 111
 112 /**
 113  *      kset - a set of kobjects of a specific type, belonging
 114  *      to a specific subsystem.
 115  *
 116  *      All kobjects of a kset should be embedded in an identical
 117  *      type. This type may have a descriptor, which the kset points
 118  *      to. This allows there to exist sets of objects of the same
 119  *      type in different subsystems.
 120  *
 121  *      A subsystem does not have to be a list of only one type
 122  *      of object; multiple ksets can belong to one subsystem. All
 123  *      ksets of a subsystem share the subsystem's lock.
 124  *
 125  *      Each kset can support specific event variables; it can
 126  *      supress the event generation or add subsystem specific
 127  *      variables carried with the event.
 128  */
 129 struct kset_uevent_ops {
 130         int (*filter)(struct kset *kset, struct kobject *kobj);
 131         const char *(*name)(struct kset *kset, struct kobject *kobj);
 132         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 133                         int num_envp, char *buffer, int buffer_size);
 134 };
 135
 136 struct kset {
 137         struct kobj_type        * ktype;
 138         struct list_head        list;
 139         spinlock_t              list_lock;
 140         struct kobject          kobj;
 141         struct kset_uevent_ops  * uevent_ops;
 142 };
 143
 144
 145 extern void kset_init(struct kset * k);
 146 extern int __must_check kset_add(struct kset * k);
 147 extern int __must_check kset_register(struct kset * k);
 148 extern void kset_unregister(struct kset * k);
 149
 150 static inline struct kset * to_kset(struct kobject * kobj)
 151 {
 152         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 153 }
 154
 155 static inline struct kset * kset_get(struct kset * k)
 156 {
 157         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 158 }
 159
 160 static inline void kset_put(struct kset * k)
 161 {
 162         kobject_put(&k->kobj);
 163 }
 164
 165 static inline struct kobj_type * get_ktype(struct kobject * k)
 166 {
 167         if (k->kset && k->kset->ktype)
 168                 return k->kset->ktype;
 169         else
 170                 return k->ktype;
 171 }
 172
 173 extern struct kobject * kset_find_obj(struct kset *, const char *);
 174
 175
 176 /**
 177  * Use this when initializing an embedded kset with no other
 178  * fields to initialize.
 179  */
 180 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 181
 182
 183 #define decl_subsys(_name,_type,_uevent_ops) \
 184 struct kset _name##_subsys = { \
 185         .kobj = { .name = __stringify(_name) }, \
 186         .ktype = _type, \
 187         .uevent_ops =_uevent_ops, \
 188 }
 189 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 190 struct kset _varname##_subsys = { \
 191         .kobj = { .name = __stringify(_name) }, \
 192         .ktype = _type, \
 193         .uevent_ops =_uevent_ops, \
 194 }
 195
 196 /* The global /sys/kernel/ subsystem for people to chain off of */
 197 extern struct kset kernel_subsys;
 198 /* The global /sys/hypervisor/ subsystem  */
 199 extern struct kset hypervisor_subsys;
 200
 201 /**
 202  * Helpers for setting the kset of registered objects.
 203  * Often, a registered object belongs to a kset embedded in a
 204  * subsystem. These do no magic, just make the resulting code
 205  * easier to follow.
 206  */
 207
 208 /**
 209  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 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 ->kobj.
 214  */
 215
 216 #define kobj_set_kset_s(obj,subsys) \
 217         (obj)->kobj.kset = &(subsys)
 218
 219 /**
 220  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 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 ->kset.
 225  *      Sets the kset of @obj's  embedded kobject (via its embedded
 226  *      kset) to @subsys.kset. This makes @obj a member of that
 227  *      kset.
 228  */
 229
 230 #define kset_set_kset_s(obj,subsys) \
 231         (obj)->kset.kobj.kset = &(subsys)
 232
 233 /**
 234  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 235  *      @obj:           ptr to some object type.
 236  *      @subsys:        a subsystem object (not a ptr).
 237  *
 238  *      Can be used for any object type with an embedded ->subsys.
 239  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 240  *      the object a member of that kset.
 241  */
 242
 243 #define subsys_set_kset(obj,_subsys) \
 244         (obj)->subsys.kobj.kset = &(_subsys)
 245
 246 extern void subsystem_init(struct kset *);
 247 extern int __must_check subsystem_register(struct kset *);
 248 extern void subsystem_unregister(struct kset *);
 249
 250 static inline struct kset *subsys_get(struct kset *s)
 251 {
 252         if (s)
 253                 return kset_get(s);
 254         return NULL;
 255 }
 256
 257 static inline void subsys_put(struct kset *s)
 258 {
 259         kset_put(s);
 260 }
 261
 262 struct subsys_attribute {
 263         struct attribute attr;
 264         ssize_t (*show)(struct kset *, char *);
 265         ssize_t (*store)(struct kset *, const char *, size_t);
 266 };
 267
 268 extern int __must_check subsys_create_file(struct kset *,
 269                                         struct subsys_attribute *);
 270
 271 #if defined(CONFIG_HOTPLUG)
 272 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 273 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 274                         char *envp[]);
 275
 276 int add_uevent_var(char **envp, int num_envp, int *cur_index,
 277                         char *buffer, int buffer_size, int *cur_len,
 278                         const char *format, ...)
 279         __attribute__((format (printf, 7, 8)));
 280 #else
 281 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 282 { return 0; }
 283 static inline int kobject_uevent_env(struct kobject *kobj,
 284                                       enum kobject_action action,
 285                                       char *envp[])
 286 { return 0; }
 287
 288 static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,
 289                                       char *buffer, int buffer_size, int *cur_len,
 290                                       const char *format, ...)
 291 { return 0; }
 292 #endif
 293
 294 #endif /* __KERNEL__ */
 295 #endif /* _KOBJECT_H_ */