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) 2006-2008 Greg Kroah-Hartman <greg@kroah.com>
   7  * Copyright (c) 2006-2008 Novell Inc.
   8  *
   9  * This file is released under the GPLv2.
  10  *
  11  * Please read Documentation/kobject.txt before using the kobject
  12  * interface, ESPECIALLY the parts about reference counts and object
  13  * destructors.
  14  */
  15
  16 #ifndef _KOBJECT_H_
  17 #define _KOBJECT_H_
  18
  19 #include <linux/types.h>
  20 #include <linux/list.h>
  21 #include <linux/sysfs.h>
  22 #include <linux/compiler.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/kref.h>
  25 #include <linux/kernel.h>
  26 #include <linux/wait.h>
  27 #include <asm/atomic.h>
  28
  29 #define KOBJ_NAME_LEN                   20
  30 #define UEVENT_HELPER_PATH_LEN          256
  31 #define UEVENT_NUM_ENVP                 32      /* number of env pointers */
  32 #define UEVENT_BUFFER_SIZE              2048    /* buffer for the variables */
  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 /*
  41  * The actions here must match the index to the string array
  42  * in lib/kobject_uevent.c
  43  *
  44  * Do not add new actions here without checking with the driver-core
  45  * maintainers. Action strings are not meant to express subsystem
  46  * or device specific properties. In most cases you want to send a
  47  * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
  48  * specific variables added to the event environment.
  49  */
  50 enum kobject_action {
  51         KOBJ_ADD,
  52         KOBJ_REMOVE,
  53         KOBJ_CHANGE,
  54         KOBJ_MOVE,
  55         KOBJ_ONLINE,
  56         KOBJ_OFFLINE,
  57         KOBJ_MAX
  58 };
  59
  60 struct kobject {
  61         const char              *name;
  62         struct kref             kref;
  63         struct list_head        entry;
  64         struct kobject          *parent;
  65         struct kset             *kset;
  66         struct kobj_type        *ktype;
  67         struct sysfs_dirent     *sd;
  68         unsigned int state_initialized:1;
  69         unsigned int state_in_sysfs:1;
  70         unsigned int state_add_uevent_sent:1;
  71         unsigned int state_remove_uevent_sent:1;
  72 };
  73
  74 extern int kobject_set_name(struct kobject *kobj, const char *name, ...)
  75                             __attribute__((format(printf, 2, 3)));
  76
  77 static inline const char *kobject_name(const struct kobject *kobj)
  78 {
  79         return kobj->name;
  80 }
  81
  82 extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
  83 extern int __must_check kobject_add(struct kobject *kobj,
  84                                     struct kobject *parent,
  85                                     const char *fmt, ...);
  86 extern int __must_check kobject_init_and_add(struct kobject *kobj,
  87                                              struct kobj_type *ktype,
  88                                              struct kobject *parent,
  89                                              const char *fmt, ...);
  90
  91 extern void kobject_del(struct kobject *kobj);
  92
  93 extern struct kobject * __must_check kobject_create(void);
  94 extern struct kobject * __must_check kobject_create_and_add(const char *name,
  95                                                 struct kobject *parent);
  96
  97 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
  98 extern int __must_check kobject_move(struct kobject *, struct kobject *);
  99
 100 extern struct kobject *kobject_get(struct kobject *kobj);
 101 extern void kobject_put(struct kobject *kobj);
 102
 103 extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
 104
 105 struct kobj_type {
 106         void (*release)(struct kobject *kobj);
 107         struct sysfs_ops *sysfs_ops;
 108         struct attribute **default_attrs;
 109 };
 110
 111 struct kobj_uevent_env {
 112         char *envp[UEVENT_NUM_ENVP];
 113         int envp_idx;
 114         char buf[UEVENT_BUFFER_SIZE];
 115         int buflen;
 116 };
 117
 118 struct kset_uevent_ops {
 119         int (*filter)(struct kset *kset, struct kobject *kobj);
 120         const char *(*name)(struct kset *kset, struct kobject *kobj);
 121         int (*uevent)(struct kset *kset, struct kobject *kobj,
 122                       struct kobj_uevent_env *env);
 123 };
 124
 125 struct kobj_attribute {
 126         struct attribute attr;
 127         ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
 128                         char *buf);
 129         ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
 130                          const char *buf, size_t count);
 131 };
 132
 133 extern struct sysfs_ops kobj_sysfs_ops;
 134
 135 /**
 136  * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
 137  *
 138  * A kset defines a group of kobjects.  They can be individually
 139  * different "types" but overall these kobjects all want to be grouped
 140  * together and operated on in the same manner.  ksets are used to
 141  * define the attribute callbacks and other common events that happen to
 142  * a kobject.
 143  *
 144  * @list: the list of all kobjects for this kset
 145  * @list_lock: a lock for iterating over the kobjects
 146  * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 147  * @uevent_ops: the set of uevent operations for this kset.  These are
 148  * called whenever a kobject has something happen to it so that the kset
 149  * can add new environment variables, or filter out the uevents if so
 150  * desired.
 151  */
 152 struct kset {
 153         struct list_head list;
 154         spinlock_t list_lock;
 155         struct kobject kobj;
 156         struct kset_uevent_ops *uevent_ops;
 157 };
 158
 159 extern void kset_init(struct kset *kset);
 160 extern int __must_check kset_register(struct kset *kset);
 161 extern void kset_unregister(struct kset *kset);
 162 extern struct kset * __must_check kset_create_and_add(const char *name,
 163                                                 struct kset_uevent_ops *u,
 164                                                 struct kobject *parent_kobj);
 165
 166 static inline struct kset *to_kset(struct kobject *kobj)
 167 {
 168         return kobj ? container_of(kobj, struct kset, kobj) : NULL;
 169 }
 170
 171 static inline struct kset *kset_get(struct kset *k)
 172 {
 173         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 174 }
 175
 176 static inline void kset_put(struct kset *k)
 177 {
 178         kobject_put(&k->kobj);
 179 }
 180
 181 static inline struct kobj_type *get_ktype(struct kobject *kobj)
 182 {
 183         return kobj->ktype;
 184 }
 185
 186 extern struct kobject *kset_find_obj(struct kset *, const char *);
 187
 188 /* The global /sys/kernel/ kobject for people to chain off of */
 189 extern struct kobject *kernel_kobj;
 190 /* The global /sys/hypervisor/ kobject for people to chain off of */
 191 extern struct kobject *hypervisor_kobj;
 192 /* The global /sys/power/ kobject for people to chain off of */
 193 extern struct kobject *power_kobj;
 194 /* The global /sys/firmware/ kobject for people to chain off of */
 195 extern struct kobject *firmware_kobj;
 196
 197 #if defined(CONFIG_HOTPLUG)
 198 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 199 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 200                         char *envp[]);
 201
 202 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 203         __attribute__((format (printf, 2, 3)));
 204
 205 int kobject_action_type(const char *buf, size_t count,
 206                         enum kobject_action *type);
 207 #else
 208 static inline int kobject_uevent(struct kobject *kobj,
 209                                  enum kobject_action action)
 210 { return 0; }
 211 static inline int kobject_uevent_env(struct kobject *kobj,
 212                                       enum kobject_action action,
 213                                       char *envp[])
 214 { return 0; }
 215
 216 static inline int add_uevent_var(struct kobj_uevent_env *env,
 217                                  const char *format, ...)
 218 { return 0; }
 219
 220 static inline int kobject_action_type(const char *buf, size_t count,
 221                                       enum kobject_action *type)
 222 { return -EINVAL; }
 223 #endif
 224
 225 #endif /* _KOBJECT_H_ */