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 struct kobject {
  62         const char              * k_name;
  63         struct kref             kref;
  64         struct list_head        entry;
  65         struct kobject          * parent;
  66         struct kset             * kset;
  67         struct kobj_type        * ktype;
  68         struct sysfs_dirent     * sd;
  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 void kobject_del(struct kobject *);
  84
  85 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
  86 extern int __must_check kobject_move(struct kobject *, struct kobject *);
  87
  88 extern int __must_check kobject_register(struct kobject *);
  89 extern void kobject_unregister(struct kobject *);
  90
  91 extern struct kobject * kobject_get(struct kobject *);
  92 extern void kobject_put(struct kobject *);
  93
  94 extern struct kobject *kobject_kset_add_dir(struct kset *kset,
  95                                             struct kobject *, const char *);
  96 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
  97
  98 extern char * kobject_get_path(struct kobject *, gfp_t);
  99
 100 struct kobj_type {
 101         void (*release)(struct kobject *);
 102         struct sysfs_ops        * sysfs_ops;
 103         struct attribute        ** default_attrs;
 104 };
 105
 106 struct kobj_uevent_env {
 107         char *envp[UEVENT_NUM_ENVP];
 108         int envp_idx;
 109         char buf[UEVENT_BUFFER_SIZE];
 110         int buflen;
 111 };
 112
 113 struct kset_uevent_ops {
 114         int (*filter)(struct kset *kset, struct kobject *kobj);
 115         const char *(*name)(struct kset *kset, struct kobject *kobj);
 116         int (*uevent)(struct kset *kset, struct kobject *kobj,
 117                       struct kobj_uevent_env *env);
 118 };
 119
 120 /**
 121  * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
 122  *
 123  * A kset defines a group of kobjects.  They can be individually
 124  * different "types" but overall these kobjects all want to be grouped
 125  * together and operated on in the same manner.  ksets are used to
 126  * define the attribute callbacks and other common events that happen to
 127  * a kobject.
 128  *
 129  * @ktype: the struct kobj_type for this specific kset
 130  * @list: the list of all kobjects for this kset
 131  * @list_lock: a lock for iterating over the kobjects
 132  * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 133  * @uevent_ops: the set of uevent operations for this kset.  These are
 134  * called whenever a kobject has something happen to it so that the kset
 135  * can add new environment variables, or filter out the uevents if so
 136  * desired.
 137  */
 138 struct kset {
 139         struct kobj_type        *ktype;
 140         struct list_head        list;
 141         spinlock_t              list_lock;
 142         struct kobject          kobj;
 143         struct kset_uevent_ops  *uevent_ops;
 144 };
 145
 146
 147 extern void kset_init(struct kset * k);
 148 extern int __must_check kset_add(struct kset * k);
 149 extern int __must_check kset_register(struct kset * k);
 150 extern void kset_unregister(struct kset * k);
 151
 152 static inline struct kset * to_kset(struct kobject * kobj)
 153 {
 154         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 155 }
 156
 157 static inline struct kset * kset_get(struct kset * k)
 158 {
 159         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 160 }
 161
 162 static inline void kset_put(struct kset * k)
 163 {
 164         kobject_put(&k->kobj);
 165 }
 166
 167 static inline struct kobj_type * get_ktype(struct kobject * k)
 168 {
 169         if (k->kset && k->kset->ktype)
 170                 return k->kset->ktype;
 171         else
 172                 return k->ktype;
 173 }
 174
 175 extern struct kobject * kset_find_obj(struct kset *, const char *);
 176
 177
 178 /*
 179  * Use this when initializing an embedded kset with no other
 180  * fields to initialize.
 181  */
 182 #define set_kset_name(str)      .kset = { .kobj = { .k_name = str } }
 183
 184
 185 #define decl_subsys(_name,_type,_uevent_ops) \
 186 struct kset _name##_subsys = { \
 187         .kobj = { .k_name = __stringify(_name) }, \
 188         .ktype = _type, \
 189         .uevent_ops =_uevent_ops, \
 190 }
 191 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 192 struct kset _varname##_subsys = { \
 193         .kobj = { .k_name = __stringify(_name) }, \
 194         .ktype = _type, \
 195         .uevent_ops =_uevent_ops, \
 196 }
 197
 198 /* The global /sys/kernel/ subsystem for people to chain off of */
 199 extern struct kset kernel_subsys;
 200 /* The global /sys/hypervisor/ subsystem  */
 201 extern struct kset 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)
 220
 221 extern int __must_check subsystem_register(struct kset *);
 222 extern void subsystem_unregister(struct kset *);
 223
 224 struct subsys_attribute {
 225         struct attribute attr;
 226         ssize_t (*show)(struct kset *, char *);
 227         ssize_t (*store)(struct kset *, const char *, size_t);
 228 };
 229
 230 extern int __must_check subsys_create_file(struct kset *,
 231                                         struct subsys_attribute *);
 232
 233 #if defined(CONFIG_HOTPLUG)
 234 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 235 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 236                         char *envp[]);
 237
 238 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 239         __attribute__((format (printf, 2, 3)));
 240
 241 int kobject_action_type(const char *buf, size_t count,
 242                         enum kobject_action *type);
 243 #else
 244 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 245 { return 0; }
 246 static inline int kobject_uevent_env(struct kobject *kobj,
 247                                       enum kobject_action action,
 248                                       char *envp[])
 249 { return 0; }
 250
 251 static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 252 { return 0; }
 253
 254 static inline int kobject_action_type(const char *buf, size_t count,
 255                         enum kobject_action *type)
 256 { return -EINVAL; }
 257 #endif
 258
 259 #endif /* __KERNEL__ */
 260 #endif /* _KOBJECT_H_ */