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