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         unsigned int state_initialized:1;
  72         unsigned int state_name_set:1;
  73         unsigned int state_in_sysfs:1;
  74         unsigned int state_add_uevent_sent:1;
  75         unsigned int state_remove_uevent_sent:1;
  76 };
  77
  78 extern int kobject_set_name(struct kobject *, const char *, ...)
  79         __attribute__((format(printf,2,3)));
  80
  81 static inline const char * kobject_name(const struct kobject * kobj)
  82 {
  83         return kobj->k_name;
  84 }
  85
  86 extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
  87 extern int __must_check kobject_add(struct kobject *kobj,
  88                                     struct kobject *parent,
  89                                     const char *fmt, ...);
  90 extern int __must_check kobject_init_and_add(struct kobject *kobj,
  91                                              struct kobj_type *ktype,
  92                                              struct kobject *parent,
  93                                              const char *fmt, ...);
  94
  95 extern void kobject_del(struct kobject *);
  96
  97 extern struct kobject * __must_check kobject_create(void);
  98 extern struct kobject * __must_check kobject_create_and_add(const char *name,
  99                                                 struct kobject *parent);
 100
 101 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
 102 extern int __must_check kobject_move(struct kobject *, struct kobject *);
 103
 104 extern void kobject_unregister(struct kobject *);
 105
 106 extern struct kobject * kobject_get(struct kobject *);
 107 extern void kobject_put(struct kobject *);
 108
 109 extern char * kobject_get_path(struct kobject *, gfp_t);
 110
 111 struct kobj_type {
 112         void (*release)(struct kobject *);
 113         struct sysfs_ops        * sysfs_ops;
 114         struct attribute        ** default_attrs;
 115 };
 116
 117 struct kobj_uevent_env {
 118         char *envp[UEVENT_NUM_ENVP];
 119         int envp_idx;
 120         char buf[UEVENT_BUFFER_SIZE];
 121         int buflen;
 122 };
 123
 124 struct kset_uevent_ops {
 125         int (*filter)(struct kset *kset, struct kobject *kobj);
 126         const char *(*name)(struct kset *kset, struct kobject *kobj);
 127         int (*uevent)(struct kset *kset, struct kobject *kobj,
 128                       struct kobj_uevent_env *env);
 129 };
 130
 131 struct kobj_attribute {
 132         struct attribute attr;
 133         ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
 134                         char *buf);
 135         ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
 136                          const char *buf, size_t count);
 137 };
 138
 139 extern struct sysfs_ops kobj_sysfs_ops;
 140
 141 /**
 142  * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
 143  *
 144  * A kset defines a group of kobjects.  They can be individually
 145  * different "types" but overall these kobjects all want to be grouped
 146  * together and operated on in the same manner.  ksets are used to
 147  * define the attribute callbacks and other common events that happen to
 148  * a kobject.
 149  *
 150  * @list: the list of all kobjects for this kset
 151  * @list_lock: a lock for iterating over the kobjects
 152  * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 153  * @uevent_ops: the set of uevent operations for this kset.  These are
 154  * called whenever a kobject has something happen to it so that the kset
 155  * can add new environment variables, or filter out the uevents if so
 156  * desired.
 157  */
 158 struct kset {
 159         struct list_head        list;
 160         spinlock_t              list_lock;
 161         struct kobject          kobj;
 162         struct kset_uevent_ops  *uevent_ops;
 163 };
 164
 165 extern void kset_init(struct kset * k);
 166 extern int __must_check kset_register(struct kset * k);
 167 extern void kset_unregister(struct kset * k);
 168 extern struct kset * __must_check kset_create_and_add(const char *name,
 169                                                 struct kset_uevent_ops *u,
 170                                                 struct kobject *parent_kobj);
 171
 172 static inline struct kset * to_kset(struct kobject * kobj)
 173 {
 174         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 175 }
 176
 177 static inline struct kset * kset_get(struct kset * k)
 178 {
 179         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 180 }
 181
 182 static inline void kset_put(struct kset * k)
 183 {
 184         kobject_put(&k->kobj);
 185 }
 186
 187 static inline struct kobj_type *get_ktype(struct kobject *kobj)
 188 {
 189         return kobj->ktype;
 190 }
 191
 192 extern struct kobject * kset_find_obj(struct kset *, const char *);
 193
 194
 195 /*
 196  * Use this when initializing an embedded kset with no other
 197  * fields to initialize.
 198  */
 199 #define set_kset_name(str)      .kset = { .kobj = { .k_name = str } }
 200
 201
 202 /* The global /sys/kernel/ kobject for people to chain off of */
 203 extern struct kobject *kernel_kobj;
 204 /* The global /sys/hypervisor/ kobject for people to chain off of */
 205 extern struct kobject *hypervisor_kobj;
 206 /* The global /sys/power/ kobject for people to chain off of */
 207 extern struct kobject *power_kobj;
 208 /* The global /sys/firmware/ kobject for people to chain off of */
 209 extern struct kobject *firmware_kobj;
 210
 211 #if defined(CONFIG_HOTPLUG)
 212 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 213 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 214                         char *envp[]);
 215
 216 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 217         __attribute__((format (printf, 2, 3)));
 218
 219 int kobject_action_type(const char *buf, size_t count,
 220                         enum kobject_action *type);
 221 #else
 222 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 223 { return 0; }
 224 static inline int kobject_uevent_env(struct kobject *kobj,
 225                                       enum kobject_action action,
 226                                       char *envp[])
 227 { return 0; }
 228
 229 static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 230 { return 0; }
 231
 232 static inline int kobject_action_type(const char *buf, size_t count,
 233                         enum kobject_action *type)
 234 { return -EINVAL; }
 235 #endif
 236
 237 #endif /* __KERNEL__ */
 238 #endif /* _KOBJECT_H_ */