[PATCH] ACPI: export acpi events via generic netlink

[Zhang Rui <rui.zhang@intel.com>]

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From: Zhang Rui <rui.zhang@intel.com>

Export ACPI events via Generic Netlink.
An "acpi_event" genetlink family message is sent
when an ACPI event is generated.

Note:	The behavior of how ACPI event works nowadays is not changed.
	Use genetlink to export ACPI event instead of
	/proc/acpi/event someday, but not now.
	This patch only adds the function of sending genetlink messages
	when an ACPI event is generated.
Attachment is a simple user space utility which can be used to receive
acpi event notifications via netlink.

Thanks to Jamal for his great help.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
---
 drivers/acpi/bus.c      |    4 +
 drivers/acpi/event.c    |  166 +++++++++++++++++++++++++++++++++++++++++++++---
 include/acpi/acpi_bus.h |    3 
 3 files changed, 165 insertions(+), 8 deletions(-)

Index: linux-2.6.22-rc5/drivers/acpi/bus.c
===================================================================
--- linux-2.6.22-rc5.orig/drivers/acpi/bus.c	2007-06-18 13:44:18.000000000 +0800
+++ linux-2.6.22-rc5/drivers/acpi/bus.c	2007-06-19 10:02:33.000000000 +0800
@@ -292,6 +292,10 @@
 	if (!device)
 		return -EINVAL;
 
+	if (acpi_bus_generate_genetlink_event(device, type, data))
+		printk(KERN_WARNING PREFIX
+			"Failed to generate an ACPI event via genetlink!\n");
+
 	/* drop event on the floor if no one's listening */
 	if (!event_is_open)
 		return 0;
Index: linux-2.6.22-rc5/drivers/acpi/event.c
===================================================================
--- linux-2.6.22-rc5.orig/drivers/acpi/event.c	2007-06-18 13:42:17.000000000 +0800
+++ linux-2.6.22-rc5/drivers/acpi/event.c	2007-06-19 11:07:15.000000000 +0800
@@ -11,6 +11,8 @@
 #include <linux/init.h>
 #include <linux/poll.h>
 #include <acpi/acpi_drivers.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
 
 #define _COMPONENT		ACPI_SYSTEM_COMPONENT
 ACPI_MODULE_NAME("event");
@@ -48,7 +50,6 @@
 	static int chars_remaining = 0;
 	static char *ptr;
 
-
 	if (!chars_remaining) {
 		memset(&event, 0, sizeof(struct acpi_bus_event));
 
@@ -106,23 +107,174 @@
 	.poll = acpi_system_poll_event,
 };
 
+#ifdef CONFIG_NET
+unsigned int acpi_event_seqnum;
+struct acpi_genl_event {
+	acpi_device_class device_class;
+	char bus_id[15];
+	u32 type;
+	u32 data;
+};
+
+/* attributes of acpi_genl_family */
+enum {
+	ACPI_GENL_ATTR_UNSPEC,
+	ACPI_GENL_ATTR_EVENT,	/* ACPI event info needed by user space */
+	__ACPI_GENL_ATTR_MAX,
+};
+#define ACPI_GENL_ATTR_MAX (__ACPI_GENL_ATTR_MAX - 1)
+
+/* commands supported by the acpi_genl_family */
+enum {
+	ACPI_GENL_CMD_UNSPEC,
+	ACPI_GENL_CMD_EVENT,	/* kernel->user notifications for ACPI events */
+	__ACPI_GENL_CMD_MAX,
+};
+#define ACPI_GENL_CMD_MAX (__ACPI_GENL_CMD_MAX - 1)
+
+#define ACPI_GENL_NAME		"acpi_event"
+#define ACPI_GENL_VERSION	0x01
+
+static struct genl_family acpi_event_genl_family = {
+	.id = GENL_ID_GENERATE,
+	.name = ACPI_GENL_NAME,
+	.version = ACPI_GENL_VERSION,
+	.maxattr = ACPI_GENL_ATTR_MAX,
+};
+
+/* .doit: standard command callback */
+static int acpi_genl_cmd_event(struct sk_buff *skb, struct genl_info *info)
+{
+	struct acpi_genl_event *event = info->userhdr;
+
+	if (!event)
+		ACPI_DEBUG_PRINT((ACPI_DB_WARN, "ACPI event: NULL\n"));
+
+	return 0;
+}
+
+static struct genl_ops acpi_event_genl_ops = {
+	.cmd = ACPI_GENL_CMD_EVENT,
+	.doit = acpi_genl_cmd_event,
+};
+
+int acpi_bus_generate_genetlink_event(struct acpi_device *device,
+				      u8 type, int data)
+{
+	struct sk_buff *skb;
+	struct nlattr *attr;
+	struct acpi_genl_event *event;
+	void *msg_header;
+	int size;
+	int result;
+
+	/* allocate memory */
+	size = nla_total_size(sizeof(struct acpi_genl_event)) +
+	    nla_total_size(0);
+
+	skb = genlmsg_new(size, GFP_ATOMIC);
+	if (!skb)
+		return -ENOMEM;
+
+	/* add the genetlink message header */
+	msg_header = genlmsg_put(skb, 0, acpi_event_seqnum++,
+				 &acpi_event_genl_family, 0,
+				 ACPI_GENL_CMD_EVENT);
+	if (!msg_header) {
+		nlmsg_free(skb);
+		return -ENOMEM;
+	}
+
+	/* fill the data */
+	attr =
+	    nla_reserve(skb, ACPI_GENL_ATTR_EVENT,
+			sizeof(struct acpi_genl_event));
+	if (!attr) {
+		nlmsg_free(skb);
+		return -EINVAL;
+	}
+
+	event = nla_data(attr);
+	if (!event) {
+		nlmsg_free(skb);
+		return -EINVAL;
+	}
+
+	memset(event, 0, sizeof(struct acpi_genl_event));
+
+	strcpy(event->device_class, device->pnp.device_class);
+	strcpy(event->bus_id, device->dev.bus_id);
+	event->type = type;
+	event->data = data;
+
+	/* send multicast genetlink message */
+	result = genlmsg_end(skb, msg_header);
+	if (result < 0) {
+		nlmsg_free(skb);
+		return result;
+	}
+
+	result =
+	    genlmsg_multicast(skb, 0, acpi_event_genl_family.id, GFP_ATOMIC);
+	if (result)
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+				  "Failed to send a Genetlink message!\n"));
+	return 0;
+}
+EXPORT_SYMBOL(acpi_bus_generate_genetlink_event);
+
+static int acpi_event_genetlink_init(void)
+{
+	int result;
+
+	result = genl_register_family(&acpi_event_genl_family);
+	if (result)
+		return result;
+
+	result =
+	    genl_register_ops(&acpi_event_genl_family, &acpi_event_genl_ops);
+	if (result)
+		genl_unregister_family(&acpi_event_genl_family);
+
+	return result;
+}
+
+#else
+int acpi_bus_generate_genetlink_event(struct acpi_device *device, u8 type,
+				      int data)
+{
+	return 0;
+}
+EXPORT_SYMBOL(acpi_bus_generate_genetlink_event);
+
+static int acpi_event_genetlink_init(void)
+{
+	return -ENODEV;
+}
+#endif
+
 static int __init acpi_event_init(void)
 {
 	struct proc_dir_entry *entry;
 	int error = 0;
 
-
 	if (acpi_disabled)
 		return 0;
 
+	/* create genetlink for acpi event */
+	error = acpi_event_genetlink_init();
+	if (error)
+		printk(KERN_WARNING PREFIX
+		       "Failed to create genetlink family for ACPI event\n");
+
 	/* 'event' [R] */
 	entry = create_proc_entry("event", S_IRUSR, acpi_root_dir);
 	if (entry)
 		entry->proc_fops = &acpi_system_event_ops;
-	else {
-		error = -ENODEV;
-	}
-	return error;
+	else
+		return -ENODEV;
+
+	return 0;
 }
 
-subsys_initcall(acpi_event_init);
+fs_initcall(acpi_event_init);
Index: linux-2.6.22-rc5/include/acpi/acpi_bus.h
===================================================================
--- linux-2.6.22-rc5.orig/include/acpi/acpi_bus.h	2007-06-18 13:44:19.000000000 +0800
+++ linux-2.6.22-rc5/include/acpi/acpi_bus.h	2007-06-19 09:18:14.000000000 +0800
@@ -321,7 +321,8 @@
 };
 
 extern struct kset acpi_subsys;
-
+extern int acpi_bus_generate_genetlink_event(struct acpi_device *device,
+						u8 type, int data);
 /*
  * External Functions
  */


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