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_add_dir(struct kobject *, const char *);
  93
  94 extern char * kobject_get_path(struct kobject *, gfp_t);
  95
  96 struct kobj_type {
  97         void (*release)(struct kobject *);
  98         struct sysfs_ops        * sysfs_ops;
  99         struct attribute        ** default_attrs;
 100 };
 101
 102
 103 /**
 104  *      kset - a set of kobjects of a specific type, belonging
 105  *      to a specific subsystem.
 106  *
 107  *      All kobjects of a kset should be embedded in an identical
 108  *      type. This type may have a descriptor, which the kset points
 109  *      to. This allows there to exist sets of objects of the same
 110  *      type in different subsystems.
 111  *
 112  *      A subsystem does not have to be a list of only one type
 113  *      of object; multiple ksets can belong to one subsystem. All
 114  *      ksets of a subsystem share the subsystem's lock.
 115  *
 116  *      Each kset can support specific event variables; it can
 117  *      supress the event generation or add subsystem specific
 118  *      variables carried with the event.
 119  */
 120 struct kset_uevent_ops {
 121         int (*filter)(struct kset *kset, struct kobject *kobj);
 122         const char *(*name)(struct kset *kset, struct kobject *kobj);
 123         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 124                         int num_envp, char *buffer, int buffer_size);
 125 };
 126
 127 struct kset {
 128         struct subsystem        * subsys;
 129         struct kobj_type        * ktype;
 130         struct list_head        list;
 131         spinlock_t              list_lock;
 132         struct kobject          kobj;
 133         struct kset_uevent_ops  * uevent_ops;
 134 };
 135
 136
 137 extern void kset_init(struct kset * k);
 138 extern int __must_check kset_add(struct kset * k);
 139 extern int __must_check kset_register(struct kset * k);
 140 extern void kset_unregister(struct kset * k);
 141
 142 static inline struct kset * to_kset(struct kobject * kobj)
 143 {
 144         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 145 }
 146
 147 static inline struct kset * kset_get(struct kset * k)
 148 {
 149         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 150 }
 151
 152 static inline void kset_put(struct kset * k)
 153 {
 154         kobject_put(&k->kobj);
 155 }
 156
 157 static inline struct kobj_type * get_ktype(struct kobject * k)
 158 {
 159         if (k->kset && k->kset->ktype)
 160                 return k->kset->ktype;
 161         else
 162                 return k->ktype;
 163 }
 164
 165 extern struct kobject * kset_find_obj(struct kset *, const char *);
 166
 167
 168 /**
 169  * Use this when initializing an embedded kset with no other
 170  * fields to initialize.
 171  */
 172 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 173
 174
 175
 176 struct subsystem {
 177         struct kset             kset;
 178         struct rw_semaphore     rwsem;
 179 };
 180
 181 #define decl_subsys(_name,_type,_uevent_ops) \
 182 struct subsystem _name##_subsys = { \
 183         .kset = { \
 184                 .kobj = { .name = __stringify(_name) }, \
 185                 .ktype = _type, \
 186                 .uevent_ops =_uevent_ops, \
 187         } \
 188 }
 189 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 190 struct subsystem _varname##_subsys = { \
 191         .kset = { \
 192                 .kobj = { .name = __stringify(_name) }, \
 193                 .ktype = _type, \
 194                 .uevent_ops =_uevent_ops, \
 195         } \
 196 }
 197
 198 /* The global /sys/kernel/ subsystem for people to chain off of */
 199 extern struct subsystem kernel_subsys;
 200 /* The global /sys/hypervisor/ subsystem  */
 201 extern struct subsystem hypervisor_subsys;
 202
 203 /**
 204  * Helpers for setting the kset of registered objects.
 205  * Often, a registered object belongs to a kset embedded in a
 206  * subsystem. These do no magic, just make the resulting code
 207  * easier to follow.
 208  */
 209
 210 /**
 211  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 212  *      @obj:           ptr to some object type.
 213  *      @subsys:        a subsystem object (not a ptr).
 214  *
 215  *      Can be used for any object type with an embedded ->kobj.
 216  */
 217
 218 #define kobj_set_kset_s(obj,subsys) \
 219         (obj)->kobj.kset = &(subsys).kset
 220
 221 /**
 222  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 223  *      @obj:           ptr to some object type.
 224  *      @subsys:        a subsystem object (not a ptr).
 225  *
 226  *      Can be used for any object type with an embedded ->kset.
 227  *      Sets the kset of @obj's  embedded kobject (via its embedded
 228  *      kset) to @subsys.kset. This makes @obj a member of that
 229  *      kset.
 230  */
 231
 232 #define kset_set_kset_s(obj,subsys) \
 233         (obj)->kset.kobj.kset = &(subsys).kset
 234
 235 /**
 236  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 237  *      @obj:           ptr to some object type.
 238  *      @subsys:        a subsystem object (not a ptr).
 239  *
 240  *      Can be used for any object type with an embedded ->subsys.
 241  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 242  *      the object a member of that kset.
 243  */
 244
 245 #define subsys_set_kset(obj,_subsys) \
 246         (obj)->subsys.kset.kobj.kset = &(_subsys).kset
 247
 248 extern void subsystem_init(struct subsystem *);
 249 extern int __must_check subsystem_register(struct subsystem *);
 250 extern void subsystem_unregister(struct subsystem *);
 251
 252 static inline struct subsystem * subsys_get(struct subsystem * s)
 253 {
 254         return s ? container_of(kset_get(&s->kset),struct subsystem,kset) : NULL;
 255 }
 256
 257 static inline void subsys_put(struct subsystem * s)
 258 {
 259         kset_put(&s->kset);
 260 }
 261
 262 struct subsys_attribute {
 263         struct attribute attr;
 264         ssize_t (*show)(struct subsystem *, char *);
 265         ssize_t (*store)(struct subsystem *, const char *, size_t);
 266 };
 267
 268 extern int __must_check subsys_create_file(struct subsystem * ,
 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_ */