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