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 #ifdef __KERNEL__
  20
  21 #include <linux/types.h>
  22 #include <linux/list.h>
  23 #include <linux/sysfs.h>
  24 #include <linux/compiler.h>
  25 #include <linux/spinlock.h>
  26 #include <linux/kref.h>
  27 #include <linux/kernel.h>
  28 #include <linux/wait.h>
  29 #include <asm/atomic.h>
  30
  31 #define KOBJ_NAME_LEN                   20
  32 #define UEVENT_HELPER_PATH_LEN          256
  33 #define UEVENT_NUM_ENVP                 32      /* number of env pointers */
  34 #define UEVENT_BUFFER_SIZE              2048    /* buffer for the variables */
  35
  36 /* path to the userspace helper executed on an event */
  37 extern char uevent_helper[];
  38
  39 /* counter to tag the uevent, read only except for the kobject core */
  40 extern u64 uevent_seqnum;
  41
  42 /*
  43  * The actions here must match the index to the string array
  44  * in lib/kobject_uevent.c
  45  *
  46  * Do not add new actions here without checking with the driver-core
  47  * maintainers. Action strings are not meant to express subsystem
  48  * or device specific properties. In most cases you want to send a
  49  * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
  50  * specific variables added to the event environment.
  51  */
  52 enum kobject_action {
  53         KOBJ_ADD,
  54         KOBJ_REMOVE,
  55         KOBJ_CHANGE,
  56         KOBJ_MOVE,
  57         KOBJ_ONLINE,
  58         KOBJ_OFFLINE,
  59         KOBJ_MAX
  60 };
  61
  62 struct kobject {
  63         const char              *name;
  64         struct kref             kref;
  65         struct list_head        entry;
  66         struct kobject          *parent;
  67         struct kset             *kset;
  68         struct kobj_type        *ktype;
  69         struct sysfs_dirent     *sd;
  70         unsigned int state_initialized:1;
  71         unsigned int state_in_sysfs:1;
  72         unsigned int state_add_uevent_sent:1;
  73         unsigned int state_remove_uevent_sent:1;
  74 };
  75
  76 extern int kobject_set_name(struct kobject *kobj, const char *name, ...)
  77                             __attribute__((format(printf, 2, 3)));
  78
  79 static inline const char *kobject_name(const struct kobject *kobj)
  80 {
  81         return kobj->name;
  82 }
  83
  84 extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
  85 extern int __must_check kobject_add(struct kobject *kobj,
  86                                     struct kobject *parent,
  87                                     const char *fmt, ...);
  88 extern int __must_check kobject_init_and_add(struct kobject *kobj,
  89                                              struct kobj_type *ktype,
  90                                              struct kobject *parent,
  91                                              const char *fmt, ...);
  92
  93 extern void kobject_del(struct kobject *kobj);
  94
  95 extern struct kobject * __must_check kobject_create(void);
  96 extern struct kobject * __must_check kobject_create_and_add(const char *name,
  97                                                 struct kobject *parent);
  98
  99 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
 100 extern int __must_check kobject_move(struct kobject *, struct kobject *);
 101
 102 extern struct kobject *kobject_get(struct kobject *kobj);
 103 extern void kobject_put(struct kobject *kobj);
 104
 105 extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
 106
 107 struct kobj_type {
 108         void (*release)(struct kobject *kobj);
 109         struct sysfs_ops *sysfs_ops;
 110         struct attribute **default_attrs;
 111 };
 112
 113 struct kobj_uevent_env {
 114         char *envp[UEVENT_NUM_ENVP];
 115         int envp_idx;
 116         char buf[UEVENT_BUFFER_SIZE];
 117         int buflen;
 118 };
 119
 120 struct kset_uevent_ops {
 121         int (*filter)(struct kset *kset, struct kobject *kobj);
 122         const char *(*name)(struct kset *kset, struct kobject *kobj);
 123         int (*uevent)(struct kset *kset, struct kobject *kobj,
 124                       struct kobj_uevent_env *env);
 125 };
 126
 127 struct kobj_attribute {
 128         struct attribute attr;
 129         ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
 130                         char *buf);
 131         ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
 132                          const char *buf, size_t count);
 133 };
 134
 135 extern struct sysfs_ops kobj_sysfs_ops;
 136
 137 /**
 138  * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
 139  *
 140  * A kset defines a group of kobjects.  They can be individually
 141  * different "types" but overall these kobjects all want to be grouped
 142  * together and operated on in the same manner.  ksets are used to
 143  * define the attribute callbacks and other common events that happen to
 144  * a kobject.
 145  *
 146  * @list: the list of all kobjects for this kset
 147  * @list_lock: a lock for iterating over the kobjects
 148  * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 149  * @uevent_ops: the set of uevent operations for this kset.  These are
 150  * called whenever a kobject has something happen to it so that the kset
 151  * can add new environment variables, or filter out the uevents if so
 152  * desired.
 153  */
 154 struct kset {
 155         struct list_head list;
 156         spinlock_t list_lock;
 157         struct kobject kobj;
 158         struct kset_uevent_ops *uevent_ops;
 159 };
 160
 161 extern void kset_init(struct kset *kset);
 162 extern int __must_check kset_register(struct kset *kset);
 163 extern void kset_unregister(struct kset *kset);
 164 extern struct kset * __must_check kset_create_and_add(const char *name,
 165                                                 struct kset_uevent_ops *u,
 166                                                 struct kobject *parent_kobj);
 167
 168 static inline struct kset *to_kset(struct kobject *kobj)
 169 {
 170         return kobj ? container_of(kobj, struct kset, kobj) : NULL;
 171 }
 172
 173 static inline struct kset *kset_get(struct kset *k)
 174 {
 175         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 176 }
 177
 178 static inline void kset_put(struct kset *k)
 179 {
 180         kobject_put(&k->kobj);
 181 }
 182
 183 static inline struct kobj_type *get_ktype(struct kobject *kobj)
 184 {
 185         return kobj->ktype;
 186 }
 187
 188 extern struct kobject *kset_find_obj(struct kset *, const char *);
 189
 190 /* The global /sys/kernel/ kobject for people to chain off of */
 191 extern struct kobject *kernel_kobj;
 192 /* The global /sys/hypervisor/ kobject for people to chain off of */
 193 extern struct kobject *hypervisor_kobj;
 194 /* The global /sys/power/ kobject for people to chain off of */
 195 extern struct kobject *power_kobj;
 196 /* The global /sys/firmware/ kobject for people to chain off of */
 197 extern struct kobject *firmware_kobj;
 198
 199 #if defined(CONFIG_HOTPLUG)
 200 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 201 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 202                         char *envp[]);
 203
 204 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 205         __attribute__((format (printf, 2, 3)));
 206
 207 int kobject_action_type(const char *buf, size_t count,
 208                         enum kobject_action *type);
 209 #else
 210 static inline int kobject_uevent(struct kobject *kobj,
 211                                  enum kobject_action action)
 212 { return 0; }
 213 static inline int kobject_uevent_env(struct kobject *kobj,
 214                                       enum kobject_action action,
 215                                       char *envp[])
 216 { return 0; }
 217
 218 static inline int add_uevent_var(struct kobj_uevent_env *env,
 219                                  const char *format, ...)
 220 { return 0; }
 221
 222 static inline int kobject_action_type(const char *buf, size_t count,
 223                                       enum kobject_action *type)
 224 { return -EINVAL; }
 225 #endif
 226
 227 #endif /* __KERNEL__ */
 228 #endif /* _KOBJECT_H_ */