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 int __must_check kobject_shadow_add(struct kobject *, struct dentry *);
  78 extern void kobject_del(struct kobject *);
  79
  80 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
  81 extern int __must_check kobject_shadow_rename(struct kobject *kobj,
  82                                                 struct dentry *new_parent,
  83                                                 const char *new_name);
  84 extern int __must_check kobject_move(struct kobject *, struct kobject *);
  85
  86 extern int __must_check kobject_register(struct kobject *);
  87 extern void kobject_unregister(struct kobject *);
  88
  89 extern struct kobject * kobject_get(struct kobject *);
  90 extern void kobject_put(struct kobject *);
  91
  92 extern struct kobject *kobject_kset_add_dir(struct kset *kset,
  93                                             struct kobject *, const char *);
  94 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
  95
  96 extern char * kobject_get_path(struct kobject *, gfp_t);
  97
  98 struct kobj_type {
  99         void (*release)(struct kobject *);
 100         struct sysfs_ops        * sysfs_ops;
 101         struct attribute        ** default_attrs;
 102 };
 103
 104
 105 /**
 106  *      kset - a set of kobjects of a specific type, belonging
 107  *      to a specific subsystem.
 108  *
 109  *      All kobjects of a kset should be embedded in an identical
 110  *      type. This type may have a descriptor, which the kset points
 111  *      to. This allows there to exist sets of objects of the same
 112  *      type in different subsystems.
 113  *
 114  *      A subsystem does not have to be a list of only one type
 115  *      of object; multiple ksets can belong to one subsystem. All
 116  *      ksets of a subsystem share the subsystem's lock.
 117  *
 118  *      Each kset can support specific event variables; it can
 119  *      supress the event generation or add subsystem specific
 120  *      variables carried with the event.
 121  */
 122 struct kset_uevent_ops {
 123         int (*filter)(struct kset *kset, struct kobject *kobj);
 124         const char *(*name)(struct kset *kset, struct kobject *kobj);
 125         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 126                         int num_envp, char *buffer, int buffer_size);
 127 };
 128
 129 struct kset {
 130         struct subsystem        * subsys;
 131         struct kobj_type        * ktype;
 132         struct list_head        list;
 133         spinlock_t              list_lock;
 134         struct kobject          kobj;
 135         struct kset_uevent_ops  * uevent_ops;
 136 };
 137
 138
 139 extern void kset_init(struct kset * k);
 140 extern int __must_check kset_add(struct kset * k);
 141 extern int __must_check kset_register(struct kset * k);
 142 extern void kset_unregister(struct kset * k);
 143
 144 static inline struct kset * to_kset(struct kobject * kobj)
 145 {
 146         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 147 }
 148
 149 static inline struct kset * kset_get(struct kset * k)
 150 {
 151         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 152 }
 153
 154 static inline void kset_put(struct kset * k)
 155 {
 156         kobject_put(&k->kobj);
 157 }
 158
 159 static inline struct kobj_type * get_ktype(struct kobject * k)
 160 {
 161         if (k->kset && k->kset->ktype)
 162                 return k->kset->ktype;
 163         else
 164                 return k->ktype;
 165 }
 166
 167 extern struct kobject * kset_find_obj(struct kset *, const char *);
 168
 169
 170 /**
 171  * Use this when initializing an embedded kset with no other
 172  * fields to initialize.
 173  */
 174 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 175
 176
 177
 178 struct subsystem {
 179         struct kset             kset;
 180         struct rw_semaphore     rwsem;
 181 };
 182
 183 #define decl_subsys(_name,_type,_uevent_ops) \
 184 struct subsystem _name##_subsys = { \
 185         .kset = { \
 186                 .kobj = { .name = __stringify(_name) }, \
 187                 .ktype = _type, \
 188                 .uevent_ops =_uevent_ops, \
 189         } \
 190 }
 191 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 192 struct subsystem _varname##_subsys = { \
 193         .kset = { \
 194                 .kobj = { .name = __stringify(_name) }, \
 195                 .ktype = _type, \
 196                 .uevent_ops =_uevent_ops, \
 197         } \
 198 }
 199
 200 /* The global /sys/kernel/ subsystem for people to chain off of */
 201 extern struct subsystem kernel_subsys;
 202 /* The global /sys/hypervisor/ subsystem  */
 203 extern struct subsystem hypervisor_subsys;
 204
 205 /**
 206  * Helpers for setting the kset of registered objects.
 207  * Often, a registered object belongs to a kset embedded in a
 208  * subsystem. These do no magic, just make the resulting code
 209  * easier to follow.
 210  */
 211
 212 /**
 213  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 214  *      @obj:           ptr to some object type.
 215  *      @subsys:        a subsystem object (not a ptr).
 216  *
 217  *      Can be used for any object type with an embedded ->kobj.
 218  */
 219
 220 #define kobj_set_kset_s(obj,subsys) \
 221         (obj)->kobj.kset = &(subsys).kset
 222
 223 /**
 224  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 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 ->kset.
 229  *      Sets the kset of @obj's  embedded kobject (via its embedded
 230  *      kset) to @subsys.kset. This makes @obj a member of that
 231  *      kset.
 232  */
 233
 234 #define kset_set_kset_s(obj,subsys) \
 235         (obj)->kset.kobj.kset = &(subsys).kset
 236
 237 /**
 238  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 239  *      @obj:           ptr to some object type.
 240  *      @subsys:        a subsystem object (not a ptr).
 241  *
 242  *      Can be used for any object type with an embedded ->subsys.
 243  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 244  *      the object a member of that kset.
 245  */
 246
 247 #define subsys_set_kset(obj,_subsys) \
 248         (obj)->subsys.kset.kobj.kset = &(_subsys).kset
 249
 250 extern void subsystem_init(struct subsystem *);
 251 extern int __must_check subsystem_register(struct subsystem *);
 252 extern void subsystem_unregister(struct subsystem *);
 253
 254 static inline struct subsystem * subsys_get(struct subsystem * s)
 255 {
 256         return s ? container_of(kset_get(&s->kset),struct subsystem,kset) : NULL;
 257 }
 258
 259 static inline void subsys_put(struct subsystem * s)
 260 {
 261         kset_put(&s->kset);
 262 }
 263
 264 struct subsys_attribute {
 265         struct attribute attr;
 266         ssize_t (*show)(struct subsystem *, char *);
 267         ssize_t (*store)(struct subsystem *, const char *, size_t);
 268 };
 269
 270 extern int __must_check subsys_create_file(struct subsystem * ,
 271                                         struct subsys_attribute *);
 272
 273 #if defined(CONFIG_HOTPLUG)
 274 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 275 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 276                         char *envp[]);
 277
 278 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         __attribute__((format (printf, 7, 8)));
 282 #else
 283 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 284 { return 0; }
 285 static inline int kobject_uevent_env(struct kobject *kobj,
 286                                       enum kobject_action action,
 287                                       char *envp[])
 288 { return 0; }
 289
 290 static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,
 291                                       char *buffer, int buffer_size, int *cur_len,
 292                                       const char *format, ...)
 293 { return 0; }
 294 #endif
 295
 296 #endif /* __KERNEL__ */
 297 #endif /* _KOBJECT_H_ */