1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * event.c - exporting ACPI events via procfs
4 *
5 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
6 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
7 *
8 */
9
10 #define pr_fmt(fmt) "ACPI: " fmt
11
12 #include <linux/spinlock.h>
13 #include <linux/export.h>
14 #include <linux/proc_fs.h>
15 #include <linux/init.h>
16 #include <linux/poll.h>
17 #include <linux/gfp.h>
18 #include <linux/acpi.h>
19 #include <net/netlink.h>
20 #include <net/genetlink.h>
21
22 #include "internal.h"
23
24 /* ACPI notifier chain */
25 static BLOCKING_NOTIFIER_HEAD(acpi_chain_head);
26
acpi_notifier_call_chain(struct acpi_device * dev,u32 type,u32 data)27 int acpi_notifier_call_chain(struct acpi_device *dev, u32 type, u32 data)
28 {
29 struct acpi_bus_event event;
30
31 strcpy(event.device_class, dev->pnp.device_class);
32 strcpy(event.bus_id, dev->pnp.bus_id);
33 event.type = type;
34 event.data = data;
35 return (blocking_notifier_call_chain(&acpi_chain_head, 0, (void *)&event)
36 == NOTIFY_BAD) ? -EINVAL : 0;
37 }
38 EXPORT_SYMBOL(acpi_notifier_call_chain);
39
register_acpi_notifier(struct notifier_block * nb)40 int register_acpi_notifier(struct notifier_block *nb)
41 {
42 return blocking_notifier_chain_register(&acpi_chain_head, nb);
43 }
44 EXPORT_SYMBOL(register_acpi_notifier);
45
unregister_acpi_notifier(struct notifier_block * nb)46 int unregister_acpi_notifier(struct notifier_block *nb)
47 {
48 return blocking_notifier_chain_unregister(&acpi_chain_head, nb);
49 }
50 EXPORT_SYMBOL(unregister_acpi_notifier);
51
52 #ifdef CONFIG_NET
53 static unsigned int acpi_event_seqnum;
54 struct acpi_genl_event {
55 acpi_device_class device_class;
56 char bus_id[15];
57 u32 type;
58 u32 data;
59 };
60
61 /* attributes of acpi_genl_family */
62 enum {
63 ACPI_GENL_ATTR_UNSPEC,
64 ACPI_GENL_ATTR_EVENT, /* ACPI event info needed by user space */
65 __ACPI_GENL_ATTR_MAX,
66 };
67 #define ACPI_GENL_ATTR_MAX (__ACPI_GENL_ATTR_MAX - 1)
68
69 /* commands supported by the acpi_genl_family */
70 enum {
71 ACPI_GENL_CMD_UNSPEC,
72 ACPI_GENL_CMD_EVENT, /* kernel->user notifications for ACPI events */
73 __ACPI_GENL_CMD_MAX,
74 };
75 #define ACPI_GENL_CMD_MAX (__ACPI_GENL_CMD_MAX - 1)
76
77 #define ACPI_GENL_FAMILY_NAME "acpi_event"
78 #define ACPI_GENL_VERSION 0x01
79 #define ACPI_GENL_MCAST_GROUP_NAME "acpi_mc_group"
80
81 static const struct genl_multicast_group acpi_event_mcgrps[] = {
82 { .name = ACPI_GENL_MCAST_GROUP_NAME, },
83 };
84
85 static struct genl_family acpi_event_genl_family __ro_after_init = {
86 .module = THIS_MODULE,
87 .name = ACPI_GENL_FAMILY_NAME,
88 .version = ACPI_GENL_VERSION,
89 .maxattr = ACPI_GENL_ATTR_MAX,
90 .mcgrps = acpi_event_mcgrps,
91 .n_mcgrps = ARRAY_SIZE(acpi_event_mcgrps),
92 };
93
acpi_bus_generate_netlink_event(const char * device_class,const char * bus_id,u8 type,int data)94 int acpi_bus_generate_netlink_event(const char *device_class,
95 const char *bus_id,
96 u8 type, int data)
97 {
98 struct sk_buff *skb;
99 struct nlattr *attr;
100 struct acpi_genl_event *event;
101 void *msg_header;
102 int size;
103
104 /* allocate memory */
105 size = nla_total_size(sizeof(struct acpi_genl_event)) +
106 nla_total_size(0);
107
108 skb = genlmsg_new(size, GFP_ATOMIC);
109 if (!skb)
110 return -ENOMEM;
111
112 /* add the genetlink message header */
113 msg_header = genlmsg_put(skb, 0, acpi_event_seqnum++,
114 &acpi_event_genl_family, 0,
115 ACPI_GENL_CMD_EVENT);
116 if (!msg_header) {
117 nlmsg_free(skb);
118 return -ENOMEM;
119 }
120
121 /* fill the data */
122 attr =
123 nla_reserve(skb, ACPI_GENL_ATTR_EVENT,
124 sizeof(struct acpi_genl_event));
125 if (!attr) {
126 nlmsg_free(skb);
127 return -EINVAL;
128 }
129
130 event = nla_data(attr);
131 memset(event, 0, sizeof(struct acpi_genl_event));
132
133 strscpy(event->device_class, device_class, sizeof(event->device_class));
134 strscpy(event->bus_id, bus_id, sizeof(event->bus_id));
135 event->type = type;
136 event->data = data;
137
138 /* send multicast genetlink message */
139 genlmsg_end(skb, msg_header);
140
141 genlmsg_multicast(&acpi_event_genl_family, skb, 0, 0, GFP_ATOMIC);
142 return 0;
143 }
144
145 EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
146
acpi_event_genetlink_init(void)147 static int __init acpi_event_genetlink_init(void)
148 {
149 return genl_register_family(&acpi_event_genl_family);
150 }
151
152 #else
acpi_bus_generate_netlink_event(const char * device_class,const char * bus_id,u8 type,int data)153 int acpi_bus_generate_netlink_event(const char *device_class,
154 const char *bus_id,
155 u8 type, int data)
156 {
157 return 0;
158 }
159
160 EXPORT_SYMBOL(acpi_bus_generate_netlink_event);
161
acpi_event_genetlink_init(void)162 static int acpi_event_genetlink_init(void)
163 {
164 return -ENODEV;
165 }
166 #endif
167
acpi_event_init(void)168 static int __init acpi_event_init(void)
169 {
170 int error;
171
172 if (acpi_disabled)
173 return 0;
174
175 /* create genetlink for acpi event */
176 error = acpi_event_genetlink_init();
177 if (error)
178 pr_warn("Failed to create genetlink family for ACPI event\n");
179
180 return 0;
181 }
182
183 fs_initcall(acpi_event_init);
184