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         unsigned int uevent_suppress:1;
  72 };
  73
  74 extern int kobject_set_name(struct kobject *kobj, const char *name, ...)
  75                             __attribute__((format(printf, 2, 3)));
  76 extern int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
  77                                   va_list vargs);
  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         const struct sysfs_ops *sysfs_ops;
 110         struct attribute **default_attrs;
 111         const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
 112         const void *(*namespace)(struct kobject *kobj);
 113 };
 114
 115 struct kobj_uevent_env {
 116         char *envp[UEVENT_NUM_ENVP];
 117         int envp_idx;
 118         char buf[UEVENT_BUFFER_SIZE];
 119         int buflen;
 120 };
 121
 122 struct kset_uevent_ops {
 123         int (* const filter)(struct kset *kset, struct kobject *kobj);
 124         const char *(* const name)(struct kset *kset, struct kobject *kobj);
 125         int (* const uevent)(struct kset *kset, struct kobject *kobj,
 126                       struct kobj_uevent_env *env);
 127 };
 128
 129 struct kobj_attribute {
 130         struct attribute attr;
 131         ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
 132                         char *buf);
 133         ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
 134                          const char *buf, size_t count);
 135 };
 136
 137 extern const struct sysfs_ops kobj_sysfs_ops;
 138
 139 /*
 140  * Namespace types which are used to tag kobjects and sysfs entries.
 141  * Network namespace will likely be the first.
 142  */
 143 enum kobj_ns_type {
 144         KOBJ_NS_TYPE_NONE = 0,
 145         KOBJ_NS_TYPE_NET,
 146         KOBJ_NS_TYPES
 147 };
 148
 149 struct sock;
 150
 151 /*
 152  * Callbacks so sysfs can determine namespaces
 153  *   @current_ns: return calling task's namespace
 154  *   @netlink_ns: return namespace to which a sock belongs (right?)
 155  *   @initial_ns: return the initial namespace (i.e. init_net_ns)
 156  */
 157 struct kobj_ns_type_operations {
 158         enum kobj_ns_type type;
 159         const void *(*current_ns)(void);
 160         const void *(*netlink_ns)(struct sock *sk);
 161         const void *(*initial_ns)(void);
 162 };
 163
 164 int kobj_ns_type_register(const struct kobj_ns_type_operations *ops);
 165 int kobj_ns_type_registered(enum kobj_ns_type type);
 166 const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent);
 167 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj);
 168
 169 const void *kobj_ns_current(enum kobj_ns_type type);
 170 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk);
 171 const void *kobj_ns_initial(enum kobj_ns_type type);
 172 void kobj_ns_exit(enum kobj_ns_type type, const void *ns);
 173
 174
 175 /**
 176  * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
 177  *
 178  * A kset defines a group of kobjects.  They can be individually
 179  * different "types" but overall these kobjects all want to be grouped
 180  * together and operated on in the same manner.  ksets are used to
 181  * define the attribute callbacks and other common events that happen to
 182  * a kobject.
 183  *
 184  * @list: the list of all kobjects for this kset
 185  * @list_lock: a lock for iterating over the kobjects
 186  * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 187  * @uevent_ops: the set of uevent operations for this kset.  These are
 188  * called whenever a kobject has something happen to it so that the kset
 189  * can add new environment variables, or filter out the uevents if so
 190  * desired.
 191  */
 192 struct kset {
 193         struct list_head list;
 194         spinlock_t list_lock;
 195         struct kobject kobj;
 196         const struct kset_uevent_ops *uevent_ops;
 197 };
 198
 199 extern void kset_init(struct kset *kset);
 200 extern int __must_check kset_register(struct kset *kset);
 201 extern void kset_unregister(struct kset *kset);
 202 extern struct kset * __must_check kset_create_and_add(const char *name,
 203                                                 const struct kset_uevent_ops *u,
 204                                                 struct kobject *parent_kobj);
 205
 206 static inline struct kset *to_kset(struct kobject *kobj)
 207 {
 208         return kobj ? container_of(kobj, struct kset, kobj) : NULL;
 209 }
 210
 211 static inline struct kset *kset_get(struct kset *k)
 212 {
 213         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 214 }
 215
 216 static inline void kset_put(struct kset *k)
 217 {
 218         kobject_put(&k->kobj);
 219 }
 220
 221 static inline struct kobj_type *get_ktype(struct kobject *kobj)
 222 {
 223         return kobj->ktype;
 224 }
 225
 226 extern struct kobject *kset_find_obj(struct kset *, const char *);
 227
 228 /* The global /sys/kernel/ kobject for people to chain off of */
 229 extern struct kobject *kernel_kobj;
 230 /* The global /sys/kernel/mm/ kobject for people to chain off of */
 231 extern struct kobject *mm_kobj;
 232 /* The global /sys/hypervisor/ kobject for people to chain off of */
 233 extern struct kobject *hypervisor_kobj;
 234 /* The global /sys/power/ kobject for people to chain off of */
 235 extern struct kobject *power_kobj;
 236 /* The global /sys/firmware/ kobject for people to chain off of */
 237 extern struct kobject *firmware_kobj;
 238
 239 #if defined(CONFIG_HOTPLUG)
 240 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 241 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 242                         char *envp[]);
 243
 244 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
 245         __attribute__((format (printf, 2, 3)));
 246
 247 int kobject_action_type(const char *buf, size_t count,
 248                         enum kobject_action *type);
 249 #else
 250 static inline int kobject_uevent(struct kobject *kobj,
 251                                  enum kobject_action action)
 252 { return 0; }
 253 static inline int kobject_uevent_env(struct kobject *kobj,
 254                                       enum kobject_action action,
 255                                       char *envp[])
 256 { return 0; }
 257
 258 static inline int add_uevent_var(struct kobj_uevent_env *env,
 259                                  const char *format, ...)
 260 { return 0; }
 261
 262 static inline int kobject_action_type(const char *buf, size_t count,
 263                                       enum kobject_action *type)
 264 { return -EINVAL; }
 265 #endif
 266
 267 #endif /* _KOBJECT_H_ */