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  * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
   7  * Copyright (c) 2006-2007 Novell Inc.
   8  *
   9  * This file is released under the GPLv2.
  10  *
  11  *
  12  * Please read Documentation/kobject.txt before using the kobject
  13  * interface, ESPECIALLY the parts about reference counts and object
  14  * destructors.
  15  */
  16
  17 #ifndef _KOBJECT_H_
  18 #define _KOBJECT_H_
  19
  20 #ifdef __KERNEL__
  21
  22 #include <linux/types.h>
  23 #include <linux/list.h>
  24 #include <linux/sysfs.h>
  25 #include <linux/compiler.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/kref.h>
  28 #include <linux/kernel.h>
  29 #include <linux/wait.h>
  30 #include <asm/atomic.h>
  31
  32 #define KOBJ_NAME_LEN                   20
  33 #define UEVENT_HELPER_PATH_LEN          256
  34 #define UEVENT_NUM_ENVP                 32      /* number of env pointers */
  35 #define UEVENT_BUFFER_SIZE              2048    /* buffer for the variables */
  36
  37 /* path to the userspace helper executed on an event */
  38 extern char uevent_helper[];
  39
  40 /* counter to tag the uevent, read only except for the kobject core */
  41 extern u64 uevent_seqnum;
  42
  43 /*
  44  * The actions here must match the index to the string array
  45  * in lib/kobject_uevent.c
  46  *
  47  * Do not add new actions here without checking with the driver-core
  48  * maintainers. Action strings are not meant to express subsystem
  49  * or device specific properties. In most cases you want to send a
  50  * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
  51  * specific variables added to the event environment.
  52  */
  53 enum kobject_action {
  54         KOBJ_ADD,
  55         KOBJ_REMOVE,
  56         KOBJ_CHANGE,
  57         KOBJ_MOVE,
  58         KOBJ_ONLINE,
  59         KOBJ_OFFLINE,
  60         KOBJ_MAX
  61 };
  62
  63 struct kobject {
  64         const char              * k_name;
  65         struct kref             kref;
  66         struct list_head        entry;
  67         struct kobject          * parent;
  68         struct kset             * kset;
  69         struct kobj_type        * ktype;
  70         struct sysfs_dirent     * sd;
  71 };
  72
  73 extern int kobject_set_name(struct kobject *, const char *, ...)
  74         __attribute__((format(printf,2,3)));
  75
  76 static inline const char * kobject_name(const struct kobject * kobj)
  77 {
  78         return kobj->k_name;
  79 }
  80
  81 extern void kobject_init(struct kobject *);
  82 extern void kobject_cleanup(struct kobject *);
  83
  84 extern int __must_check kobject_add(struct kobject *);
  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_move(struct kobject *, struct kobject *);
  89
  90 extern int __must_check kobject_register(struct kobject *);
  91 extern void kobject_unregister(struct kobject *);
  92
  93 extern struct kobject * kobject_get(struct kobject *);
  94 extern void kobject_put(struct kobject *);
  95
  96 extern struct kobject *kobject_kset_add_dir(struct kset *kset,
  97                                             struct kobject *, const char *);
  98 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
  99
 100 extern char * kobject_get_path(struct kobject *, gfp_t);
 101
 102 struct kobj_type {
 103         void (*release)(struct kobject *);
 104         struct sysfs_ops        * sysfs_ops;
 105         struct attribute        ** default_attrs;
 106 };
 107
 108 struct kobj_uevent_env {
 109         char *envp[UEVENT_NUM_ENVP];
 110         int envp_idx;
 111         char buf[UEVENT_BUFFER_SIZE];
 112         int buflen;
 113 };
 114
 115 struct kset_uevent_ops {
 116         int (*filter)(struct kset *kset, struct kobject *kobj);
 117         const char *(*name)(struct kset *kset, struct kobject *kobj);
 118         int (*uevent)(struct kset *kset, struct kobject *kobj,
 119                       struct kobj_uevent_env *env);
 120 };
 121
 122 /**
 123  * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
 124  *
 125  * A kset defines a group of kobjects.  They can be individually
 126  * different "types" but overall these kobjects all want to be grouped
 127  * together and operated on in the same manner.  ksets are used to
 128  * define the attribute callbacks and other common events that happen to
 129  * a kobject.
 130  *
 131  * @ktype: the struct kobj_type for this specific kset
 132  * @list: the list of all kobjects for this kset
 133  * @list_lock: a lock for iterating over the kobjects
 134  * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 135  * @uevent_ops: the set of uevent operations for this kset.  These are
 136  * called whenever a kobject has something happen to it so that the kset
 137  * can add new environment variables, or filter out the uevents if so
 138  * desired.
 139  */
 140 struct kset {
 141         struct kobj_type        *ktype;
 142         struct list_head        list;
 143         spinlock_t              list_lock;
 144         struct kobject          kobj;
 145         struct kset_uevent_ops  *uevent_ops;
 146 };
 147
 148
 149 extern void kset_init(struct kset * k);
 150 extern int __must_check kset_add(struct kset * k);
 151 extern int __must_check kset_register(struct kset * k);
 152 extern void kset_unregister(struct kset * k);
 153
 154 static inline struct kset * to_kset(struct kobject * kobj)
 155 {
 156         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 157 }
 158
 159 static inline struct kset * kset_get(struct kset * k)
 160 {
 161         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 162 }
 163
 164 static inline void kset_put(struct kset * k)
 165 {
 166         kobject_put(&k->kobj);
 167 }
 168
 169 static inline struct kobj_type * get_ktype(struct kobject * k)
 170 {
 171         if (k->kset && k->kset->ktype)
 172                 return k->kset->ktype;
 173         else
 174                 return k->ktype;
 175 }
 176
 177 extern struct kobject * kset_find_obj(struct kset *, const char *);
 178
 179
 180 /*
 181  * Use this when initializing an embedded kset with no other
 182  * fields to initialize.
 183  */
 184 #define set_kset_name(str)      .kset = { .kobj = { .k_name = str } }
 185
 186
 187 #define decl_subsys(_name,_type,_uevent_ops) \
 188 struct kset _name##_subsys = { \
 189         .kobj = { .k_name = __stringify(_name) }, \
 190         .ktype = _type, \
 191         .uevent_ops =_uevent_ops, \
 192 }
 193 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 194 struct kset _varname##_subsys = { \
 195         .kobj = { .k_name = __stringify(_name) }, \
 196         .ktype = _type, \
 197         .uevent_ops =_uevent_ops, \
 198 }
 199
 200 /* The global /sys/kernel/ subsystem for people to chain off of */
 201 extern struct kset kernel_subsys;
 202 /* The global /sys/hypervisor/ subsystem  */
 203 extern struct kset 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)
 222
 223 extern int __must_check subsystem_register(struct kset *);
 224 extern void subsystem_unregister(struct kset *);
 225
 226 struct subsys_attribute {
 227         struct attribute attr;
 228         ssize_t (*show)(struct kset *, char *);
 229         ssize_t (*store)(struct kset *, const char *, size_t);
 230 };
 231
 232 extern int __must_check subsys_create_file(struct kset *,
 233                                         struct subsys_attribute *);
 234
 235 #if defined(CONFIG_HOTPLUG)
 236 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 237 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 238                         char *envp[]);
 239
 240 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 241         __attribute__((format (printf, 2, 3)));
 242
 243 int kobject_action_type(const char *buf, size_t count,
 244                         enum kobject_action *type);
 245 #else
 246 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 247 { return 0; }
 248 static inline int kobject_uevent_env(struct kobject *kobj,
 249                                       enum kobject_action action,
 250                                       char *envp[])
 251 { return 0; }
 252
 253 static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 254 { return 0; }
 255
 256 static inline int kobject_action_type(const char *buf, size_t count,
 257                         enum kobject_action *type)
 258 { return -EINVAL; }
 259 #endif
 260
 261 #endif /* __KERNEL__ */
 262 #endif /* _KOBJECT_H_ */