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         struct kref             kref;
  67         struct list_head        entry;
  68         struct kobject          * parent;
  69         struct kset             * kset;
  70         struct kobj_type        * ktype;
  71         struct sysfs_dirent     * sd;
  72         wait_queue_head_t       poll;
  73 };
  74
  75 extern int kobject_set_name(struct kobject *, const char *, ...)
  76         __attribute__((format(printf,2,3)));
  77
  78 static inline const char * kobject_name(const struct kobject * kobj)
  79 {
  80         return kobj->k_name;
  81 }
  82
  83 extern void kobject_init(struct kobject *);
  84 extern void kobject_cleanup(struct kobject *);
  85
  86 extern int __must_check kobject_add(struct kobject *);
  87 extern int __must_check kobject_shadow_add(struct kobject *kobj,
  88                                            struct sysfs_dirent *shadow_parent);
  89 extern void kobject_del(struct kobject *);
  90
  91 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
  92 extern int __must_check kobject_shadow_rename(struct kobject *kobj,
  93                                               struct sysfs_dirent *new_parent,
  94                                               const char *new_name);
  95 extern int __must_check kobject_move(struct kobject *, struct kobject *);
  96
  97 extern int __must_check kobject_register(struct kobject *);
  98 extern void kobject_unregister(struct kobject *);
  99
 100 extern struct kobject * kobject_get(struct kobject *);
 101 extern void kobject_put(struct kobject *);
 102
 103 extern struct kobject *kobject_kset_add_dir(struct kset *kset,
 104                                             struct kobject *, const char *);
 105 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
 106
 107 extern char * kobject_get_path(struct kobject *, gfp_t);
 108
 109 struct kobj_type {
 110         void (*release)(struct kobject *);
 111         struct sysfs_ops        * sysfs_ops;
 112         struct attribute        ** default_attrs;
 113 };
 114
 115 struct kobj_uevent_env {
 116         char *envp[UEVENT_NUM_ENVP];
 117         int envp_idx;
 118         char buf[UEVENT_BUFFER_SIZE];
 119         int buflen;
 120 };
 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,
 126                       struct kobj_uevent_env *env);
 127 };
 128
 129 /*
 130  *      struct kset - a set of kobjects of a specific type, belonging
 131  *      to a specific subsystem.
 132  *
 133  *      All kobjects of a kset should be embedded in an identical
 134  *      type. This type may have a descriptor, which the kset points
 135  *      to. This allows there to exist sets of objects of the same
 136  *      type in different subsystems.
 137  *
 138  *      A subsystem does not have to be a list of only one type
 139  *      of object; multiple ksets can belong to one subsystem. All
 140  *      ksets of a subsystem share the subsystem's lock.
 141  *
 142  *      Each kset can support specific event variables; it can
 143  *      supress the event generation or add subsystem specific
 144  *      variables carried with the event.
 145  */
 146 struct kset {
 147         struct kobj_type        * ktype;
 148         struct list_head        list;
 149         spinlock_t              list_lock;
 150         struct kobject          kobj;
 151         struct kset_uevent_ops  * uevent_ops;
 152 };
 153
 154
 155 extern void kset_init(struct kset * k);
 156 extern int __must_check kset_add(struct kset * k);
 157 extern int __must_check kset_register(struct kset * k);
 158 extern void kset_unregister(struct kset * k);
 159
 160 static inline struct kset * to_kset(struct kobject * kobj)
 161 {
 162         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 163 }
 164
 165 static inline struct kset * kset_get(struct kset * k)
 166 {
 167         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 168 }
 169
 170 static inline void kset_put(struct kset * k)
 171 {
 172         kobject_put(&k->kobj);
 173 }
 174
 175 static inline struct kobj_type * get_ktype(struct kobject * k)
 176 {
 177         if (k->kset && k->kset->ktype)
 178                 return k->kset->ktype;
 179         else
 180                 return k->ktype;
 181 }
 182
 183 extern struct kobject * kset_find_obj(struct kset *, const char *);
 184
 185
 186 /*
 187  * Use this when initializing an embedded kset with no other
 188  * fields to initialize.
 189  */
 190 #define set_kset_name(str)      .kset = { .kobj = { .k_name = str } }
 191
 192
 193 #define decl_subsys(_name,_type,_uevent_ops) \
 194 struct kset _name##_subsys = { \
 195         .kobj = { .k_name = __stringify(_name) }, \
 196         .ktype = _type, \
 197         .uevent_ops =_uevent_ops, \
 198 }
 199 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 200 struct kset _varname##_subsys = { \
 201         .kobj = { .k_name = __stringify(_name) }, \
 202         .ktype = _type, \
 203         .uevent_ops =_uevent_ops, \
 204 }
 205
 206 /* The global /sys/kernel/ subsystem for people to chain off of */
 207 extern struct kset kernel_subsys;
 208 /* The global /sys/hypervisor/ subsystem  */
 209 extern struct kset hypervisor_subsys;
 210
 211 /*
 212  * Helpers for setting the kset of registered objects.
 213  * Often, a registered object belongs to a kset embedded in a
 214  * subsystem. These do no magic, just make the resulting code
 215  * easier to follow.
 216  */
 217
 218 /**
 219  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 220  *      @obj:           ptr to some object type.
 221  *      @subsys:        a subsystem object (not a ptr).
 222  *
 223  *      Can be used for any object type with an embedded ->kobj.
 224  */
 225
 226 #define kobj_set_kset_s(obj,subsys) \
 227         (obj)->kobj.kset = &(subsys)
 228
 229 extern void subsystem_init(struct kset *);
 230 extern int __must_check subsystem_register(struct kset *);
 231 extern void subsystem_unregister(struct kset *);
 232
 233 struct subsys_attribute {
 234         struct attribute attr;
 235         ssize_t (*show)(struct kset *, char *);
 236         ssize_t (*store)(struct kset *, const char *, size_t);
 237 };
 238
 239 extern int __must_check subsys_create_file(struct kset *,
 240                                         struct subsys_attribute *);
 241
 242 #if defined(CONFIG_HOTPLUG)
 243 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 244 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 245                         char *envp[]);
 246
 247 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 248         __attribute__((format (printf, 2, 3)));
 249 #else
 250 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 251 { return 0; }
 252 static inline int kobject_uevent_env(struct kobject *kobj,
 253                                       enum kobject_action action,
 254                                       char *envp[])
 255 { return 0; }
 256
 257 static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 258 { return 0; }
 259 #endif
 260
 261 #endif /* __KERNEL__ */
 262 #endif /* _KOBJECT_H_ */