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/kobject_ns.h>
  26 #include <linux/kernel.h>
  27 #include <linux/wait.h>
  28 #include <asm/atomic.h>
  29
  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 list_head        entry;
  63         struct kobject          *parent;
  64         struct kset             *kset;
  65         struct kobj_type        *ktype;
  66         struct sysfs_dirent     *sd;
  67         struct kref             kref;
  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         unsigned int uevent_suppress:1;
  73 };
  74
  75 extern int kobject_set_name(struct kobject *kobj, const char *name, ...)
  76                             __attribute__((format(printf, 2, 3)));
  77 extern int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
  78                                   va_list vargs);
  79
  80 static inline const char *kobject_name(const struct kobject *kobj)
  81 {
  82         return kobj->name;
  83 }
  84
  85 extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
  86 extern int __must_check kobject_add(struct kobject *kobj,
  87                                     struct kobject *parent,
  88                                     const char *fmt, ...);
  89 extern int __must_check kobject_init_and_add(struct kobject *kobj,
  90                                              struct kobj_type *ktype,
  91                                              struct kobject *parent,
  92                                              const char *fmt, ...);
  93
  94 extern void kobject_del(struct kobject *kobj);
  95
  96 extern struct kobject * __must_check kobject_create(void);
  97 extern struct kobject * __must_check kobject_create_and_add(const char *name,
  98                                                 struct kobject *parent);
  99
 100 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
 101 extern int __must_check kobject_move(struct kobject *, struct kobject *);
 102
 103 extern struct kobject *kobject_get(struct kobject *kobj);
 104 extern void kobject_put(struct kobject *kobj);
 105
 106 extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
 107
 108 struct kobj_type {
 109         void (*release)(struct kobject *kobj);
 110         const struct sysfs_ops *sysfs_ops;
 111         struct attribute **default_attrs;
 112         const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
 113         const void *(*namespace)(struct kobject *kobj);
 114 };
 115
 116 struct kobj_uevent_env {
 117         char *envp[UEVENT_NUM_ENVP];
 118         int envp_idx;
 119         char buf[UEVENT_BUFFER_SIZE];
 120         int buflen;
 121 };
 122
 123 struct kset_uevent_ops {
 124         int (* const filter)(struct kset *kset, struct kobject *kobj);
 125         const char *(* const name)(struct kset *kset, struct kobject *kobj);
 126         int (* const uevent)(struct kset *kset, struct kobject *kobj,
 127                       struct kobj_uevent_env *env);
 128 };
 129
 130 struct kobj_attribute {
 131         struct attribute attr;
 132         ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
 133                         char *buf);
 134         ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
 135                          const char *buf, size_t count);
 136 };
 137
 138 extern const struct sysfs_ops kobj_sysfs_ops;
 139
 140 struct sock;
 141
 142 /**
 143  * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
 144  *
 145  * A kset defines a group of kobjects.  They can be individually
 146  * different "types" but overall these kobjects all want to be grouped
 147  * together and operated on in the same manner.  ksets are used to
 148  * define the attribute callbacks and other common events that happen to
 149  * a kobject.
 150  *
 151  * @list: the list of all kobjects for this kset
 152  * @list_lock: a lock for iterating over the kobjects
 153  * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 154  * @uevent_ops: the set of uevent operations for this kset.  These are
 155  * called whenever a kobject has something happen to it so that the kset
 156  * can add new environment variables, or filter out the uevents if so
 157  * desired.
 158  */
 159 struct kset {
 160         struct list_head list;
 161         spinlock_t list_lock;
 162         struct kobject kobj;
 163         const struct kset_uevent_ops *uevent_ops;
 164 };
 165
 166 extern void kset_init(struct kset *kset);
 167 extern int __must_check kset_register(struct kset *kset);
 168 extern void kset_unregister(struct kset *kset);
 169 extern struct kset * __must_check kset_create_and_add(const char *name,
 170                                                 const struct kset_uevent_ops *u,
 171                                                 struct kobject *parent_kobj);
 172
 173 static inline struct kset *to_kset(struct kobject *kobj)
 174 {
 175         return kobj ? container_of(kobj, struct kset, kobj) : NULL;
 176 }
 177
 178 static inline struct kset *kset_get(struct kset *k)
 179 {
 180         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 181 }
 182
 183 static inline void kset_put(struct kset *k)
 184 {
 185         kobject_put(&k->kobj);
 186 }
 187
 188 static inline struct kobj_type *get_ktype(struct kobject *kobj)
 189 {
 190         return kobj->ktype;
 191 }
 192
 193 extern struct kobject *kset_find_obj(struct kset *, const char *);
 194 extern struct kobject *kset_find_obj_hinted(struct kset *, const char *,
 195                                                 struct kobject *);
 196
 197 /* The global /sys/kernel/ kobject for people to chain off of */
 198 extern struct kobject *kernel_kobj;
 199 /* The global /sys/kernel/mm/ kobject for people to chain off of */
 200 extern struct kobject *mm_kobj;
 201 /* The global /sys/hypervisor/ kobject for people to chain off of */
 202 extern struct kobject *hypervisor_kobj;
 203 /* The global /sys/power/ kobject for people to chain off of */
 204 extern struct kobject *power_kobj;
 205 /* The global /sys/firmware/ kobject for people to chain off of */
 206 extern struct kobject *firmware_kobj;
 207
 208 #if defined(CONFIG_HOTPLUG)
 209 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 210 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 211                         char *envp[]);
 212
 213 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 214         __attribute__((format (printf, 2, 3)));
 215
 216 int kobject_action_type(const char *buf, size_t count,
 217                         enum kobject_action *type);
 218 #else
 219 static inline int kobject_uevent(struct kobject *kobj,
 220                                  enum kobject_action action)
 221 { return 0; }
 222 static inline int kobject_uevent_env(struct kobject *kobj,
 223                                       enum kobject_action action,
 224                                       char *envp[])
 225 { return 0; }
 226
 227 static inline int add_uevent_var(struct kobj_uevent_env *env,
 228                                  const char *format, ...)
 229 { return 0; }
 230
 231 static inline int kobject_action_type(const char *buf, size_t count,
 232                                       enum kobject_action *type)
 233 { return -EINVAL; }
 234 #endif
 235
 236 #endif /* _KOBJECT_H_ */