// SPDX-License-Identifier: GPL-2.0
/*
 * event.c - exporting ACPI events via procfs
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *
 */

#define pr_fmt(fmt) "ACPI: " fmt

#include <linux/spinlock.h>
#include <linux/export.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/gfp.h>
#include <linux/acpi.h>
#include <net/netlink.h>
#include <net/genetlink.h>

#include "internal.h"

/* ACPI notifier chain */
static BLOCKING_NOTIFIER_HEAD(acpi_chain_head);

int acpi_notifier_call_chain(struct acpi_device *dev, u32 type, u32 data)
{
        struct acpi_bus_event event;

        strscpy(event.device_class, dev->pnp.device_class);
        strscpy(event.bus_id, dev->pnp.bus_id);
        event.type = type;
        event.data = data;
        return (blocking_notifier_call_chain(&acpi_chain_head, 0, (void *)&event)
                        == NOTIFY_BAD) ? -EINVAL : 0;
}
EXPORT_SYMBOL(acpi_notifier_call_chain);

int register_acpi_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&acpi_chain_head, nb);
}
EXPORT_SYMBOL(register_acpi_notifier);

int unregister_acpi_notifier(struct notifier_block *nb)
{
        return blocking_notifier_chain_unregister(&acpi_chain_head, nb);
}
EXPORT_SYMBOL(unregister_acpi_notifier);

#ifdef CONFIG_NET
static 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_FAMILY_NAME           "acpi_event"
#define ACPI_GENL_VERSION               0x01
#define ACPI_GENL_MCAST_GROUP_NAME      "acpi_mc_group"

static const struct genl_multicast_group acpi_event_mcgrps[] = {
        { .name = ACPI_GENL_MCAST_GROUP_NAME, },
};

static struct genl_family acpi_event_genl_family __ro_after_init = {
        .module = THIS_MODULE,
        .name = ACPI_GENL_FAMILY_NAME,
        .version = ACPI_GENL_VERSION,
        .maxattr = ACPI_GENL_ATTR_MAX,
        .mcgrps = acpi_event_mcgrps,
        .n_mcgrps = ARRAY_SIZE(acpi_event_mcgrps),
};

int acpi_bus_generate_netlink_event(const char *device_class,
                                      const char *bus_id,
                                      u8 type, int data)
{
        struct sk_buff *skb;
        struct nlattr *attr;
        struct acpi_genl_event *event;
        void *msg_header;
        int size;

        /* 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);
        memset(event, 0, sizeof(struct acpi_genl_event));

        strscpy(event->device_class, device_class, sizeof(event->device_class));
        strscpy(event->bus_id, bus_id, sizeof(event->bus_id));
        event->type = type;
        event->data = data;

        /* send multicast genetlink message */
        genlmsg_end(skb, msg_header);

        genlmsg_multicast(&acpi_event_genl_family, skb, 0, 0, GFP_ATOMIC);
        return 0;
}

EXPORT_SYMBOL(acpi_bus_generate_netlink_event);

static int __init acpi_event_genetlink_init(void)
{
        return genl_register_family(&acpi_event_genl_family);
}

#else
int acpi_bus_generate_netlink_event(const char *device_class,
                                      const char *bus_id,
                                      u8 type, int data)
{
        return 0;
}

EXPORT_SYMBOL(acpi_bus_generate_netlink_event);

static int acpi_event_genetlink_init(void)
{
        return -ENODEV;
}
#endif

static int __init acpi_event_init(void)
{
        int error;

        if (acpi_disabled)
                return 0;

        /* create genetlink for acpi event */
        error = acpi_event_genetlink_init();
        if (error)
                pr_warn("Failed to create genetlink family for ACPI event\n");

        return 0;
}

fs_initcall(acpi_event_init);