/*-
 * Copyright (c) 2005-2006 The FreeBSD Project
 * All rights reserved.
 *
 * Author: Victor Cruceru <soc-victor@freebsd.org>
 *
 * Redistribution of this software and documentation and use in source and
 * binary forms, with or without modification, are permitted provided that
 * the following conditions are met:
 *
 * 1. Redistributions of source code or documentation must retain the above
 *    copyright notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Host Resources MIB: hrDeviceTable implementation for SNMPd.
 */

#include <sys/un.h>
#include <sys/limits.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <sysexits.h>

#include "hostres_snmp.h"
#include "hostres_oid.h"
#include "hostres_tree.h"

#define FREE_DEV_STRUCT(entry_p) do {           \
        free(entry_p->name);                    \
        free(entry_p->location);                \
        free(entry_p->descr);                   \
        free(entry_p);                          \
} while (0)

/*
 * Status of a device
 */
enum DeviceStatus {
        DS_UNKNOWN      = 1,
        DS_RUNNING      = 2,
        DS_WARNING      = 3,
        DS_TESTING      = 4,
        DS_DOWN         = 5
};

TAILQ_HEAD(device_tbl, device_entry);

/* the head of the list with hrDeviceTable's entries */
static struct device_tbl device_tbl = TAILQ_HEAD_INITIALIZER(device_tbl);

/* Table used for consistent device table indexing. */
struct device_map device_map = STAILQ_HEAD_INITIALIZER(device_map);

/* next int available for indexing the hrDeviceTable */
static uint32_t next_device_index = 1;

/* last (agent) tick when hrDeviceTable was updated */
static uint64_t device_tick = 0;

/* maximum number of ticks between updates of device table */
uint32_t device_tbl_refresh = 10 * 100;

/* socket for /var/run/devd.pipe */
static int devd_sock = -1;

/* used to wait notifications from /var/run/devd.pipe */
static void *devd_fd;

/* some constants */
static const struct asn_oid OIDX_hrDeviceProcessor_c = OIDX_hrDeviceProcessor;
static const struct asn_oid OIDX_hrDeviceOther_c = OIDX_hrDeviceOther;

/**
 * Create a new entry out of thin air.
 */
struct device_entry *
device_entry_create(const char *name, const char *location, const char *descr)
{
        struct device_entry *entry = NULL;
        struct device_map_entry *map = NULL;
        size_t name_len;
        size_t location_len;

        assert((name[0] != 0) || (location[0] != 0));

        if (name[0] == 0 && location[0] == 0)
                return (NULL);

        STAILQ_FOREACH(map, &device_map, link) {
                assert(map->name_key != NULL);
                assert(map->location_key != NULL);

                if (strcmp(map->name_key, name) == 0 &&
                    strcmp(map->location_key, location) == 0) {
                        break;
                }
        }

        if (map == NULL) {
                /* new object - get a new index */
                if (next_device_index > INT_MAX) {
                        syslog(LOG_ERR,
                            "%s: hrDeviceTable index wrap", __func__);
                        /* There isn't much we can do here.
                         * If the next_swins_index is consumed
                         * then we can't add entries to this table
                         * So it is better to exit - if the table is sparsed
                         * at the next agent run we can fill it fully.
                         */
                        errx(EX_SOFTWARE, "hrDeviceTable index wrap");
                        /* not reachable */
                }

                if ((map = malloc(sizeof(*map))) == NULL) {
                        syslog(LOG_ERR, "hrDeviceTable: %s: %m", __func__ );
                        return (NULL);
                }

                map->entry_p = NULL;

                name_len = strlen(name) + 1;
                if (name_len > DEV_NAME_MLEN)
                        name_len = DEV_NAME_MLEN;

                if ((map->name_key = malloc(name_len)) == NULL) {
                        syslog(LOG_ERR, "hrDeviceTable: %s: %m", __func__ );
                        free(map);
                        return (NULL);
                }

                location_len = strlen(location) + 1;
                if (location_len > DEV_LOC_MLEN)
                        location_len = DEV_LOC_MLEN;

                if ((map->location_key = malloc(location_len )) == NULL) {
                        syslog(LOG_ERR, "hrDeviceTable: %s: %m", __func__ );
                        free(map->name_key);
                        free(map);
                        return (NULL);
                }

                map->hrIndex = next_device_index++;

                strlcpy(map->name_key, name, name_len);
                strlcpy(map->location_key, location, location_len);

                STAILQ_INSERT_TAIL(&device_map, map, link);
                HRDBG("%s at %s added into hrDeviceMap at index=%d",
                    name, location, map->hrIndex);
        } else {
                HRDBG("%s at %s exists in hrDeviceMap index=%d",
                    name, location, map->hrIndex);
        }

        if ((entry = malloc(sizeof(*entry))) == NULL) {
                syslog(LOG_WARNING, "hrDeviceTable: %s: %m", __func__);
                return (NULL);
        }
        memset(entry, 0, sizeof(*entry));

        entry->index = map->hrIndex;
        map->entry_p = entry;

        if ((entry->name = strdup(map->name_key)) == NULL) {
                syslog(LOG_ERR, "hrDeviceTable: %s: %m", __func__ );
                free(entry);
                return (NULL);
        }

        if ((entry->location = strdup(map->location_key)) == NULL) {
                syslog(LOG_ERR, "hrDeviceTable: %s: %m", __func__ );
                free(entry->name);
                free(entry);
                return (NULL);
        }

        /*
         * From here till the end of this function we reuse name_len
         * for a different purpose - for device_entry::descr
         */
        if (name[0] != '\0')
                name_len = strlen(name) + strlen(descr) +
                    strlen(": ") + 1;
        else
                name_len = strlen(location) + strlen(descr) +
                    strlen("unknown at : ") + 1;

        if (name_len > DEV_DESCR_MLEN)
                name_len = DEV_DESCR_MLEN;

        if ((entry->descr = malloc(name_len )) == NULL) {
                syslog(LOG_ERR, "hrDeviceTable: %s: %m", __func__ );
                free(entry->name);
                free(entry->location);
                free(entry);
                return (NULL);
        }

        memset(&entry->descr[0], '\0', name_len);

        if (name[0] != '\0')
                snprintf(entry->descr, name_len,
                    "%s: %s", name, descr);
        else
                snprintf(entry->descr, name_len,
                    "unknown at %s: %s", location, descr);

        entry->id = &oid_zeroDotZero;   /* unknown id - FIXME */
        entry->status = (u_int)DS_UNKNOWN;
        entry->errors = 0;
        entry->type = &OIDX_hrDeviceOther_c;

        INSERT_OBJECT_INT(entry, &device_tbl);

        return (entry);
}

/**
 * Create a new entry into the device table.
 */
static struct device_entry *
device_entry_create_devinfo(const struct devinfo_dev *dev_p)
{

        assert(dev_p->dd_name != NULL);
        assert(dev_p->dd_location != NULL);

        return (device_entry_create(dev_p->dd_name, dev_p->dd_location,
            dev_p->dd_desc));
}

/**
 * Delete an entry from the device table.
 */
void
device_entry_delete(struct device_entry *entry)
{
        struct device_map_entry *map;

        assert(entry != NULL);

        TAILQ_REMOVE(&device_tbl, entry, link);

        STAILQ_FOREACH(map, &device_map, link)
                if (map->entry_p == entry) {
                        map->entry_p = NULL;
                        break;
                }

        FREE_DEV_STRUCT(entry);
}

/**
 * Find an entry given its name and location
 */
static struct device_entry *
device_find_by_dev(const struct devinfo_dev *dev_p)
{
        struct device_map_entry  *map;

        assert(dev_p != NULL);

        STAILQ_FOREACH(map, &device_map, link)
                if (strcmp(map->name_key, dev_p->dd_name) == 0 &&
                    strcmp(map->location_key, dev_p->dd_location) == 0)
                        return (map->entry_p);
        return (NULL);
}

/**
 * Find an entry given its index.
 */
struct device_entry *
device_find_by_index(int32_t idx)
{
        struct device_entry *entry;

        TAILQ_FOREACH(entry, &device_tbl, link)
                if (entry->index == idx)
                        return (entry);
        return (NULL);
}

/**
 * Find an device entry given its name.
 */
struct device_entry *
device_find_by_name(const char *dev_name)
{
        struct device_map_entry *map;

        assert(dev_name != NULL);

        STAILQ_FOREACH(map, &device_map, link)
                if (strcmp(map->name_key, dev_name) == 0)
                        return (map->entry_p);

        return (NULL);
}

/**
 * Find out the type of device. CPU only currently.
 */
static void
device_get_type(struct devinfo_dev *dev_p, const struct asn_oid **out_type_p)
{

        assert(dev_p != NULL);
        assert(out_type_p != NULL);

        if (dev_p == NULL)
                return;

        if (strncmp(dev_p->dd_name, "cpu", strlen("cpu")) == 0 &&
            strstr(dev_p->dd_location, ".CPU") != NULL) {
                *out_type_p = &OIDX_hrDeviceProcessor_c;
                return;
        }
}

/**
 * Get the status of a device
 */
static enum DeviceStatus
device_get_status(struct devinfo_dev *dev)
{

        assert(dev != NULL);

        switch (dev->dd_state) {
        case DS_ALIVE:                  /* probe succeeded */
        case DS_NOTPRESENT:             /* not probed or probe failed */
                return (DS_DOWN);
        case DS_ATTACHED:               /* attach method called */
                return (DS_RUNNING);
        default:
                return (DS_UNKNOWN);
        }
}

/**
 * Get the info for the given device and then recursively process all
 * child devices.
 */
static int
device_collector(struct devinfo_dev *dev, void *arg)
{
        struct device_entry *entry;

        HRDBG("%llu/%llu name='%s' desc='%s' drivername='%s' location='%s'",
            (unsigned long long)dev->dd_handle,
            (unsigned long long)dev->dd_parent, dev->dd_name, dev->dd_desc,
            dev->dd_drivername, dev->dd_location);

        if (dev->dd_name[0] != '\0' || dev->dd_location[0] != '\0') {
                HRDBG("ANALYZING dev %s at %s",
                    dev->dd_name, dev->dd_location);

                if ((entry = device_find_by_dev(dev)) != NULL) {
                        entry->flags |= HR_DEVICE_FOUND;
                        entry->status = (u_int)device_get_status(dev);
                } else if ((entry = device_entry_create_devinfo(dev)) != NULL) {
                        device_get_type(dev, &entry->type);

                        entry->flags |= HR_DEVICE_FOUND;
                        entry->status = (u_int)device_get_status(dev);
                }
        } else {
                HRDBG("SKIPPED unknown device at location '%s'",
                    dev->dd_location );
        }

        return (devinfo_foreach_device_child(dev, device_collector, arg));
}

/**
 * Create the socket to the device daemon.
 */
static int
create_devd_socket(void)
{
        int d_sock;
        struct sockaddr_un devd_addr;

        bzero(&devd_addr, sizeof(struct sockaddr_un));

        if ((d_sock = socket(PF_LOCAL, SOCK_STREAM, 0)) < 0) {
                syslog(LOG_ERR, "Failed to create the socket for %s: %m",
                    PATH_DEVD_PIPE);
                return (-1);
        }

        devd_addr.sun_family = PF_LOCAL;
        devd_addr.sun_len = sizeof(devd_addr);
        strlcpy(devd_addr.sun_path, PATH_DEVD_PIPE,
            sizeof(devd_addr.sun_path) - 1);

        if (connect(d_sock, (struct sockaddr *)&devd_addr,
            sizeof(devd_addr)) == -1) {
                syslog(LOG_ERR,"Failed to connect socket for %s: %m",
                    PATH_DEVD_PIPE);
                if (close(d_sock) < 0 )
                        syslog(LOG_ERR,"Failed to close socket for %s: %m",
                            PATH_DEVD_PIPE);
                return (-1);
        }

        return (d_sock);
}

/*
 * Event on the devd socket.
 *
 * We should probably directly process entries here. For simplicity just
 * call the refresh routine with the force flag for now.
 */
static void
devd_socket_callback(int fd, void *arg __unused)
{
        char buf[512];
        int read_len = -1;

        assert(fd == devd_sock);

        HRDBG("called");

again:
        read_len = read(fd, buf, sizeof(buf));
        if (read_len < 0) {
                if (errno == EBADF) {
                        devd_sock = -1;
                        if (devd_fd != NULL) {
                                fd_deselect(devd_fd);
                                devd_fd = NULL;
                        }
                        syslog(LOG_ERR, "Closing devd_fd, revert to "
                            "devinfo polling");
                }

        } else if (read_len == 0) {
                syslog(LOG_ERR, "zero bytes read from devd pipe... "
                    "closing socket!");

                if (close(devd_sock) < 0 )
                        syslog(LOG_ERR, "Failed to close devd socket: %m");

                devd_sock = -1;
                if (devd_fd != NULL) {
                        fd_deselect(devd_fd);
                        devd_fd = NULL;
                }
                syslog(LOG_ERR, "Closing devd_fd, revert to devinfo polling");

        } else {
                if (read_len == sizeof(buf))
                        goto again;
                /* Only refresh device table on a device add or remove event. */
                if (buf[0] == '+' || buf[0] == '-')
                        refresh_device_tbl(1);
        }
}

/**
 * Initialize and populate the device table.
 */
void
init_device_tbl(void)
{

        /* initially populate table for the other tables */
        refresh_device_tbl(1);

        /* no problem if that fails - just use polling mode */
        devd_sock = create_devd_socket();
}

/**
 * Start devd(8) monitoring.
 */
void
start_device_tbl(struct lmodule *mod)
{

        if (devd_sock > 0) {
                devd_fd = fd_select(devd_sock, devd_socket_callback, NULL, mod);
                if (devd_fd == NULL)
                        syslog(LOG_ERR, "fd_select failed on devd socket: %m");
        }
}

/**
 * Finalization routine for hrDeviceTable
 * It destroys the lists and frees any allocated heap memory
 */
void
fini_device_tbl(void)
{
        struct device_map_entry *n1;

        if (devd_fd != NULL)
                fd_deselect(devd_fd);

        if (devd_sock != -1)
                (void)close(devd_sock);

        devinfo_free();

        while ((n1 = STAILQ_FIRST(&device_map)) != NULL) {
                STAILQ_REMOVE_HEAD(&device_map, link);
                if (n1->entry_p != NULL) {
                        TAILQ_REMOVE(&device_tbl, n1->entry_p, link);
                        FREE_DEV_STRUCT(n1->entry_p);
                }
                free(n1->name_key);
                free(n1->location_key);
                free(n1);
        }
        assert(TAILQ_EMPTY(&device_tbl));
}

/**
 * Refresh routine for hrDeviceTable. We don't refresh here if the devd socket
 * is open, because in this case we have the actual information always. We
 * also don't refresh when the table is new enough (if we don't have a devd
 * socket). In either case a refresh can be forced by passing a non-zero value.
 */
void
refresh_device_tbl(int force)
{
        struct device_entry *entry, *entry_tmp;
        struct devinfo_dev *dev_root;
        static int act = 0;

        if (!force && (devd_sock >= 0 ||
           (device_tick != 0 && this_tick - device_tick < device_tbl_refresh))){
                HRDBG("no refresh needed");
                return;
        }

        if (act) {
                syslog(LOG_ERR, "%s: recursive call", __func__);
                return;
        }

        if (devinfo_init() != 0) {
                syslog(LOG_ERR,"%s: devinfo_init failed: %m", __func__);
                return;
        }

        act = 1;
        if ((dev_root = devinfo_handle_to_device(DEVINFO_ROOT_DEVICE)) == NULL){
                syslog(LOG_ERR, "%s: can't get the root device: %m", __func__);
                goto out;
        }

        /* mark each entry as missing */
        TAILQ_FOREACH(entry, &device_tbl, link)
                entry->flags &= ~HR_DEVICE_FOUND;

        if (devinfo_foreach_device_child(dev_root, device_collector, NULL))
                syslog(LOG_ERR, "%s: devinfo_foreach_device_child failed",
                    __func__);

        /*
         * Purge items that disappeared
         */
        TAILQ_FOREACH_SAFE(entry, &device_tbl, link, entry_tmp) {
                /*
                 * If HR_DEVICE_IMMUTABLE bit is set then this means that
                 * this entry was not detected by the above
                 * devinfo_foreach_device() call. So we are not deleting
                 * it there.
                 */
                if (!(entry->flags & HR_DEVICE_FOUND) &&
                    !(entry->flags & HR_DEVICE_IMMUTABLE))
                        device_entry_delete(entry);
        }

        device_tick = this_tick;

        /*
         * Force a refresh for the hrDiskStorageTable
         * XXX Why not the other dependen tables?
         */
        refresh_disk_storage_tbl(1);

  out:
        devinfo_free();
        act = 0;
}

/**
 * This is the implementation for a generated (by a SNMP tool)
 * function prototype, see hostres_tree.h
 * It handles the SNMP operations for hrDeviceTable
 */
int
op_hrDeviceTable(struct snmp_context *ctx __unused, struct snmp_value *value,
    u_int sub, u_int iidx __unused, enum snmp_op curr_op)
{
        struct device_entry *entry;

        refresh_device_tbl(0);

        switch (curr_op) {

        case SNMP_OP_GETNEXT:
                if ((entry = NEXT_OBJECT_INT(&device_tbl,
                    &value->var, sub)) == NULL)
                        return (SNMP_ERR_NOSUCHNAME);
                value->var.len = sub + 1;
                value->var.subs[sub] = entry->index;
                goto get;

        case SNMP_OP_GET:
                if ((entry = FIND_OBJECT_INT(&device_tbl,
                    &value->var, sub)) == NULL)
                        return (SNMP_ERR_NOSUCHNAME);
                goto get;

        case SNMP_OP_SET:
                if ((entry = FIND_OBJECT_INT(&device_tbl,
                    &value->var, sub)) == NULL)
                        return (SNMP_ERR_NO_CREATION);
                return (SNMP_ERR_NOT_WRITEABLE);

        case SNMP_OP_ROLLBACK:
        case SNMP_OP_COMMIT:
                abort();
        }
        abort();

  get:
        switch (value->var.subs[sub - 1]) {

        case LEAF_hrDeviceIndex:
                value->v.integer = entry->index;
                return (SNMP_ERR_NOERROR);

        case LEAF_hrDeviceType:
                assert(entry->type != NULL);
                value->v.oid = *(entry->type);
                return (SNMP_ERR_NOERROR);

        case LEAF_hrDeviceDescr:
                return (string_get(value, entry->descr, -1));

        case LEAF_hrDeviceID:
                value->v.oid = *(entry->id);
                return (SNMP_ERR_NOERROR);

        case LEAF_hrDeviceStatus:
                value->v.integer = entry->status;
                return (SNMP_ERR_NOERROR);

        case LEAF_hrDeviceErrors:
                value->v.uint32 = entry->errors;
                return (SNMP_ERR_NOERROR);
        }
        abort();
}