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 <linux/atomic.h>
  29 #include <linux/workqueue.h>
  30
  31 #define UEVENT_HELPER_PATH_LEN          256
  32 #define UEVENT_NUM_ENVP                 32      /* number of env pointers */
  33 #define UEVENT_BUFFER_SIZE              2048    /* buffer for the variables */
  34
  35 #ifdef CONFIG_UEVENT_HELPER
  36 /* path to the userspace helper executed on an event */
  37 extern char uevent_helper[];
  38 #endif
  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              *name;
  65         struct list_head        entry;
  66         struct kobject          *parent;
  67         struct kset             *kset;
  68         struct kobj_type        *ktype;
  69         struct kernfs_node      *sd; /* sysfs directory entry */
  70         struct kref             kref;
  71 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
  72         struct delayed_work     release;
  73 #endif
  74         unsigned int state_initialized:1;
  75         unsigned int state_in_sysfs:1;
  76         unsigned int state_add_uevent_sent:1;
  77         unsigned int state_remove_uevent_sent:1;
  78         unsigned int uevent_suppress:1;
  79 };
  80
  81 extern __printf(2, 3)
  82 int kobject_set_name(struct kobject *kobj, const char *name, ...);
  83 extern __printf(2, 0)
  84 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
  85                            va_list vargs);
  86
  87 static inline const char *kobject_name(const struct kobject *kobj)
  88 {
  89         return kobj->name;
  90 }
  91
  92 extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
  93 extern __printf(3, 4) __must_check
  94 int kobject_add(struct kobject *kobj, struct kobject *parent,
  95                 const char *fmt, ...);
  96 extern __printf(4, 5) __must_check
  97 int kobject_init_and_add(struct kobject *kobj,
  98                          struct kobj_type *ktype, struct kobject *parent,
  99                          const char *fmt, ...);
 100
 101 extern void kobject_del(struct kobject *kobj);
 102
 103 extern struct kobject * __must_check kobject_create(void);
 104 extern struct kobject * __must_check kobject_create_and_add(const char *name,
 105                                                 struct kobject *parent);
 106
 107 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
 108 extern int __must_check kobject_move(struct kobject *, struct kobject *);
 109
 110 extern struct kobject *kobject_get(struct kobject *kobj);
 111 extern struct kobject * __must_check kobject_get_unless_zero(
 112                                                 struct kobject *kobj);
 113 extern void kobject_put(struct kobject *kobj);
 114
 115 extern const void *kobject_namespace(struct kobject *kobj);
 116 extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
 117
 118 struct kobj_type {
 119         void (*release)(struct kobject *kobj);
 120         const struct sysfs_ops *sysfs_ops;
 121         struct attribute **default_attrs;
 122         const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
 123         const void *(*namespace)(struct kobject *kobj);
 124 };
 125
 126 struct kobj_uevent_env {
 127         char *argv[3];
 128         char *envp[UEVENT_NUM_ENVP];
 129         int envp_idx;
 130         char buf[UEVENT_BUFFER_SIZE];
 131         int buflen;
 132 };
 133
 134 struct kset_uevent_ops {
 135         int (* const filter)(struct kset *kset, struct kobject *kobj);
 136         const char *(* const name)(struct kset *kset, struct kobject *kobj);
 137         int (* const uevent)(struct kset *kset, struct kobject *kobj,
 138                       struct kobj_uevent_env *env);
 139 };
 140
 141 struct kobj_attribute {
 142         struct attribute attr;
 143         ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
 144                         char *buf);
 145         ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
 146                          const char *buf, size_t count);
 147 };
 148
 149 extern const struct sysfs_ops kobj_sysfs_ops;
 150
 151 struct sock;
 152
 153 /**
 154  * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
 155  *
 156  * A kset defines a group of kobjects.  They can be individually
 157  * different "types" but overall these kobjects all want to be grouped
 158  * together and operated on in the same manner.  ksets are used to
 159  * define the attribute callbacks and other common events that happen to
 160  * a kobject.
 161  *
 162  * @list: the list of all kobjects for this kset
 163  * @list_lock: a lock for iterating over the kobjects
 164  * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 165  * @uevent_ops: the set of uevent operations for this kset.  These are
 166  * called whenever a kobject has something happen to it so that the kset
 167  * can add new environment variables, or filter out the uevents if so
 168  * desired.
 169  */
 170 struct kset {
 171         struct list_head list;
 172         spinlock_t list_lock;
 173         struct kobject kobj;
 174         const struct kset_uevent_ops *uevent_ops;
 175 } __randomize_layout;
 176
 177 extern void kset_init(struct kset *kset);
 178 extern int __must_check kset_register(struct kset *kset);
 179 extern void kset_unregister(struct kset *kset);
 180 extern struct kset * __must_check kset_create_and_add(const char *name,
 181                                                 const struct kset_uevent_ops *u,
 182                                                 struct kobject *parent_kobj);
 183
 184 static inline struct kset *to_kset(struct kobject *kobj)
 185 {
 186         return kobj ? container_of(kobj, struct kset, kobj) : NULL;
 187 }
 188
 189 static inline struct kset *kset_get(struct kset *k)
 190 {
 191         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 192 }
 193
 194 static inline void kset_put(struct kset *k)
 195 {
 196         kobject_put(&k->kobj);
 197 }
 198
 199 static inline struct kobj_type *get_ktype(struct kobject *kobj)
 200 {
 201         return kobj->ktype;
 202 }
 203
 204 extern struct kobject *kset_find_obj(struct kset *, const char *);
 205
 206 /* The global /sys/kernel/ kobject for people to chain off of */
 207 extern struct kobject *kernel_kobj;
 208 /* The global /sys/kernel/mm/ kobject for people to chain off of */
 209 extern struct kobject *mm_kobj;
 210 /* The global /sys/hypervisor/ kobject for people to chain off of */
 211 extern struct kobject *hypervisor_kobj;
 212 /* The global /sys/power/ kobject for people to chain off of */
 213 extern struct kobject *power_kobj;
 214 /* The global /sys/firmware/ kobject for people to chain off of */
 215 extern struct kobject *firmware_kobj;
 216
 217 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 218 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 219                         char *envp[]);
 220 int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
 221
 222 __printf(2, 3)
 223 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
 224
 225 #endif /* _KOBJECT_H_ */