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_init_ng(struct kobject *kobj, struct kobj_type *ktype);
  83 extern int __must_check kobject_add(struct kobject *);
  84 extern int __must_check kobject_add_ng(struct kobject *kobj,
  85                                        struct kobject *parent,
  86                                        const char *fmt, ...);
  87 extern int __must_check kobject_init_and_add(struct kobject *kobj,
  88                                              struct kobj_type *ktype,
  89                                              struct kobject *parent,
  90                                              const char *fmt, ...);
  91
  92 extern void kobject_del(struct kobject *);
  93
  94 extern int __must_check kobject_rename(struct kobject *, 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 to a specific subsystem.
 131  *
 132  * A kset defines a group of kobjects.  They can be individually
 133  * different "types" but overall these kobjects all want to be grouped
 134  * together and operated on in the same manner.  ksets are used to
 135  * define the attribute callbacks and other common events that happen to
 136  * a kobject.
 137  *
 138  * @list: the list of all kobjects for this kset
 139  * @list_lock: a lock for iterating over the kobjects
 140  * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 141  * @uevent_ops: the set of uevent operations for this kset.  These are
 142  * called whenever a kobject has something happen to it so that the kset
 143  * can add new environment variables, or filter out the uevents if so
 144  * desired.
 145  */
 146 struct kset {
 147         struct list_head        list;
 148         spinlock_t              list_lock;
 149         struct kobject          kobj;
 150         struct kset_uevent_ops  *uevent_ops;
 151 };
 152
 153 extern void kset_init(struct kset * k);
 154 extern int __must_check kset_add(struct kset * k);
 155 extern int __must_check kset_register(struct kset * k);
 156 extern void kset_unregister(struct kset * k);
 157 extern struct kset * __must_check kset_create_and_add(const char *name,
 158                                                 struct kset_uevent_ops *u,
 159                                                 struct kobject *parent_kobj);
 160
 161 static inline struct kset * to_kset(struct kobject * kobj)
 162 {
 163         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 164 }
 165
 166 static inline struct kset * kset_get(struct kset * k)
 167 {
 168         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 169 }
 170
 171 static inline void kset_put(struct kset * k)
 172 {
 173         kobject_put(&k->kobj);
 174 }
 175
 176 static inline struct kobj_type *get_ktype(struct kobject *kobj)
 177 {
 178         return kobj->ktype;
 179 }
 180
 181 extern struct kobject * kset_find_obj(struct kset *, const char *);
 182
 183
 184 /*
 185  * Use this when initializing an embedded kset with no other
 186  * fields to initialize.
 187  */
 188 #define set_kset_name(str)      .kset = { .kobj = { .k_name = str } }
 189
 190
 191 #define decl_subsys(_name,_uevent_ops) \
 192 struct kset _name##_subsys = { \
 193         .kobj = { .k_name = __stringify(_name) }, \
 194         .uevent_ops =_uevent_ops, \
 195 }
 196 #define decl_subsys_name(_varname,_name,_uevent_ops) \
 197 struct kset _varname##_subsys = { \
 198         .kobj = { .k_name = __stringify(_name) }, \
 199         .uevent_ops =_uevent_ops, \
 200 }
 201
 202 /* The global /sys/kernel/ subsystem for people to chain off of */
 203 extern struct kset kernel_subsys;
 204 /* The global /sys/hypervisor/ subsystem  */
 205 extern struct kset hypervisor_subsys;
 206
 207 extern int __must_check subsystem_register(struct kset *);
 208 extern void subsystem_unregister(struct kset *);
 209
 210 struct subsys_attribute {
 211         struct attribute attr;
 212         ssize_t (*show)(struct kset *, char *);
 213         ssize_t (*store)(struct kset *, const char *, size_t);
 214 };
 215
 216 extern int __must_check subsys_create_file(struct kset *,
 217                                         struct subsys_attribute *);
 218
 219 #if defined(CONFIG_HOTPLUG)
 220 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 221 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 222                         char *envp[]);
 223
 224 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 225         __attribute__((format (printf, 2, 3)));
 226
 227 int kobject_action_type(const char *buf, size_t count,
 228                         enum kobject_action *type);
 229 #else
 230 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 231 { return 0; }
 232 static inline int kobject_uevent_env(struct kobject *kobj,
 233                                       enum kobject_action action,
 234                                       char *envp[])
 235 { return 0; }
 236
 237 static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 238 { return 0; }
 239
 240 static inline int kobject_action_type(const char *buf, size_t count,
 241                         enum kobject_action *type)
 242 { return -EINVAL; }
 243 #endif
 244
 245 #endif /* __KERNEL__ */
 246 #endif /* _KOBJECT_H_ */