/*-
 * 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 for SNMPd. Implementation for hrStorageTable
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/vmmeter.h>
#include <sys/mount.h>

#include <vm/vm_param.h>

#include <assert.h>
#include <err.h>
#include <limits.h>
#include <memstat.h>
#include <paths.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h> /* for getpagesize() */
#include <sysexits.h>

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

/* maximum length for description string according to MIB */
#define SE_DESC_MLEN    (255 + 1)

/*
 * This structure is used to hold a SNMP table entry
 * for HOST-RESOURCES-MIB's hrStorageTable
 */
struct storage_entry {
        int32_t         index;
        const struct asn_oid *type;
        u_char          *descr;
        int32_t         allocationUnits;
        int32_t         size;
        int32_t         used;
        uint32_t        allocationFailures;
#define HR_STORAGE_FOUND 0x001
        uint32_t        flags;  /* to be used internally*/
        TAILQ_ENTRY(storage_entry) link;
};
TAILQ_HEAD(storage_tbl, storage_entry);

/*
 * Next structure is used to keep o list of mappings from a specific name
 * (a_name) to an entry in the hrStorageTblEntry. We are trying to keep the
 * same index for a specific name at least for the duration of one SNMP agent
 * run.
 */
struct storage_map_entry {
        int32_t         hrIndex; /* used for storage_entry::index */

        /* map key, also used for storage_entry::descr */
        u_char          *a_name;

        /*
         * next may be NULL if the respective storage_entry
         * is (temporally) gone
         */
        struct storage_entry *entry;
        STAILQ_ENTRY(storage_map_entry) link;
};
STAILQ_HEAD(storage_map, storage_map_entry);

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

/*for consistent table indexing*/
static struct storage_map storage_map =
    STAILQ_HEAD_INITIALIZER(storage_map);

/* last (agent) tick when hrStorageTable was updated */
static uint64_t storage_tick;

/* maximum number of ticks between two refreshs */
uint32_t storage_tbl_refresh = HR_STORAGE_TBL_REFRESH * 100;

/* for kvm_getswapinfo, malloc'd */
static struct kvm_swap *swap_devs;
static size_t swap_devs_len;            /* item count for swap_devs */

/* for getfsstat, malloc'd */
static struct statfs *fs_buf;
static size_t fs_buf_count;             /* item count for fs_buf */

static struct vmtotal mem_stats;

/* next int available for indexing the hrStorageTable */
static uint32_t next_storage_index = 1;

/* start of list for memory detailed stats */
static struct memory_type_list *mt_list;

/* Constants */
static const struct asn_oid OIDX_hrStorageRam_c = OIDX_hrStorageRam;
static const struct asn_oid OIDX_hrStorageVirtualMemory_c =
    OIDX_hrStorageVirtualMemory;

/**
 * Create a new entry into the storage table and, if necessary, an
 * entry into the storage map.
 */
static struct storage_entry *
storage_entry_create(const char *name)
{
        struct storage_entry *entry;
        struct storage_map_entry *map;
        size_t name_len;

        assert(name != NULL);
        assert(strlen(name) > 0);

        STAILQ_FOREACH(map, &storage_map, link)
                if (strcmp(map->a_name, name) == 0)
                        break;

        if (map == NULL) {
                /* new object - get a new index */
                if (next_storage_index > INT_MAX) {
                        syslog(LOG_ERR,
                            "%s: hrStorageTable index wrap", __func__);
                        errx(EX_SOFTWARE, "hrStorageTable index wrap");
                }

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

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

                if ((map->a_name = malloc(name_len)) == NULL) {
                        free(map);
                        return (NULL);
                }

                strlcpy(map->a_name, name, name_len);
                map->hrIndex = next_storage_index++;

                STAILQ_INSERT_TAIL(&storage_map, map, link);

                HRDBG("%s added into hrStorageMap at index=%d",
                    name, map->hrIndex);
        } else {
                HRDBG("%s exists in hrStorageMap index=%d\n",
                    name, map->hrIndex);
        }

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

        entry->index = map->hrIndex;

        if ((entry->descr = strdup(map->a_name)) == NULL) {
                free(entry);
                return (NULL);
        }

        map->entry = entry;

        INSERT_OBJECT_INT(entry, &storage_tbl);

        return (entry);
}

/**
 * Delete an entry from the storage table.
 */
static void
storage_entry_delete(struct storage_entry *entry)
{
        struct storage_map_entry *map;

        assert(entry != NULL);

        TAILQ_REMOVE(&storage_tbl, entry, link);
        STAILQ_FOREACH(map, &storage_map, link)
                if (map->entry == entry) {
                        map->entry = NULL;
                        break;
                }
        free(entry->descr);
        free(entry);
}

/**
 * Find a table entry by its name.
 */
static struct storage_entry *
storage_find_by_name(const char *name)
{
        struct storage_entry *entry;

        TAILQ_FOREACH(entry, &storage_tbl, link)
                if (strcmp(entry->descr, name) == 0)
                        return (entry);

        return (NULL);
}

/*
 * VM info.
 */
static void
storage_OS_get_vm(void)
{
        int mib[2] = { CTL_VM, VM_TOTAL };
        size_t len = sizeof(mem_stats);
        int page_size_bytes;
        struct storage_entry *entry;

        if (sysctl(mib, 2, &mem_stats, &len, NULL, 0) < 0) {
                syslog(LOG_ERR,
                    "hrStoragetable: %s: sysctl({CTL_VM, VM_METER}) "
                    "failed: %m", __func__);
                assert(0);
                return;
        }

        page_size_bytes = getpagesize();

        /* Real Memory Metrics */
        if ((entry = storage_find_by_name("Real Memory Metrics")) == NULL &&
            (entry = storage_entry_create("Real Memory Metrics")) == NULL)
                return; /* I'm out of luck now, maybe next time */

        entry->flags |= HR_STORAGE_FOUND;
        entry->type = &OIDX_hrStorageRam_c;
        entry->allocationUnits = page_size_bytes;
        entry->size = mem_stats.t_rm;
        entry->used = mem_stats.t_arm; /* ACTIVE is not USED - FIXME */
        entry->allocationFailures = 0;

        /* Shared Real Memory Metrics */
        if ((entry = storage_find_by_name("Shared Real Memory Metrics")) ==
            NULL &&
            (entry = storage_entry_create("Shared Real Memory Metrics")) ==
            NULL)
                return;

        entry->flags |= HR_STORAGE_FOUND;
        entry->type = &OIDX_hrStorageRam_c;
        entry->allocationUnits = page_size_bytes;
        entry->size = mem_stats.t_rmshr;
        /* ACTIVE is not USED - FIXME */
        entry->used = mem_stats.t_armshr;
        entry->allocationFailures = 0;
}

static void
storage_OS_get_memstat(void)
{
        struct memory_type *mt_item;
        struct storage_entry *entry;

        if (mt_list == NULL) {
                if ((mt_list = memstat_mtl_alloc()) == NULL)
                        /* again? we have a serious problem */
                return;
        }

        if (memstat_sysctl_all(mt_list, 0) < 0) {
                syslog(LOG_ERR, "memstat_sysctl_all failed: %s",
                    memstat_strerror(memstat_mtl_geterror(mt_list)) );
                return;
        }

        if ((mt_item = memstat_mtl_first(mt_list)) == NULL) {
                /* usually this is not an error, no errno for this failure*/
                HRDBG("memstat_mtl_first failed");
                return;
        }

        do {
                const char *memstat_name;
                uint64_t tmp_size;
                int allocator;
                char alloc_descr[SE_DESC_MLEN];

                memstat_name = memstat_get_name(mt_item);

                if (memstat_name == NULL || strlen(memstat_name) == 0)
                        continue;

                switch (allocator = memstat_get_allocator(mt_item)) {

                  case ALLOCATOR_MALLOC:
                        snprintf(alloc_descr, sizeof(alloc_descr),
                            "MALLOC: %s", memstat_name);
                        break;

                  case ALLOCATOR_UMA:
                        snprintf(alloc_descr, sizeof(alloc_descr),
                            "UMA: %s", memstat_name);
                        break;

                  default:
                        snprintf(alloc_descr, sizeof(alloc_descr),
                            "UNKNOWN%d: %s", allocator, memstat_name);
                        break;
                }

                if ((entry = storage_find_by_name(alloc_descr)) == NULL &&
                    (entry = storage_entry_create(alloc_descr)) == NULL)
                        return;

                entry->flags |= HR_STORAGE_FOUND;
                entry->type = &OIDX_hrStorageRam_c;

                if ((tmp_size = memstat_get_size(mt_item)) == 0)
                        tmp_size = memstat_get_sizemask(mt_item);
                entry->allocationUnits =
                    (tmp_size  > INT_MAX ? INT_MAX : (int32_t)tmp_size);

                tmp_size  = memstat_get_countlimit(mt_item);
                entry->size =
                    (tmp_size  > INT_MAX ? INT_MAX : (int32_t)tmp_size);

                tmp_size = memstat_get_count(mt_item);
                entry->used =
                    (tmp_size  > INT_MAX ? INT_MAX : (int32_t)tmp_size);

                tmp_size = memstat_get_failures(mt_item);
                entry->allocationFailures =
                    (tmp_size  > INT_MAX ? INT_MAX : (int32_t)tmp_size);

        } while((mt_item = memstat_mtl_next(mt_item)) != NULL);
}

/**
 * Get swap info
 */
static void
storage_OS_get_swap(void)
{
        struct storage_entry *entry;
        char swap_w_prefix[SE_DESC_MLEN];
        size_t len;
        int nswapdev;

        len = sizeof(nswapdev);
        nswapdev = 0;

        if (sysctlbyname("vm.nswapdev", &nswapdev, &len, NULL,0 ) < 0) {
                syslog(LOG_ERR,
                    "hrStorageTable: sysctlbyname(\"vm.nswapdev\") "
                    "failed. %m");
                assert(0);
                return;
        }

        if (nswapdev <= 0) {
                HRDBG("vm.nswapdev is %d", nswapdev);
                return;
        }

        if (nswapdev + 1 != (int)swap_devs_len || swap_devs == NULL) {
                swap_devs_len = nswapdev + 1;
                swap_devs = reallocf(swap_devs,
                    swap_devs_len * sizeof(struct kvm_swap));

                assert(swap_devs != NULL);
                if (swap_devs == NULL) {
                        swap_devs_len = 0;
                        return;
                }
        }

        nswapdev = kvm_getswapinfo(hr_kd, swap_devs, swap_devs_len, 0);
        if (nswapdev < 0) {
                syslog(LOG_ERR,
                    "hrStorageTable: kvm_getswapinfo failed. %m\n");
                assert(0);
                return;
        }

        for (len = 0; len < (size_t)nswapdev; len++) {
                memset(&swap_w_prefix[0], '\0', sizeof(swap_w_prefix));
                snprintf(swap_w_prefix, sizeof(swap_w_prefix) - 1,
                    "Swap:%s%s", _PATH_DEV, swap_devs[len].ksw_devname);

                entry = storage_find_by_name(swap_w_prefix);
                if (entry == NULL)
                        entry = storage_entry_create(swap_w_prefix);

                assert (entry != NULL);
                if (entry == NULL)
                        return; /* Out of luck */

                entry->flags |= HR_STORAGE_FOUND;
                entry->type = &OIDX_hrStorageVirtualMemory_c;
                entry->allocationUnits = getpagesize();
                entry->size = swap_devs[len].ksw_total;
                entry->used = swap_devs[len].ksw_used;
                entry->allocationFailures = 0;
        }
}

/**
 * Query the underlaying OS for the mounted file systems
 * anf fill in the respective lists (for hrStorageTable and for hrFSTable)
 */
static void
storage_OS_get_fs(void)
{
        struct storage_entry *entry;
        uint64_t size, used;
        int i, mounted_fs_count, units;
        char fs_string[SE_DESC_MLEN];

        if ((mounted_fs_count = getfsstat(NULL, 0, MNT_NOWAIT)) < 0) {
                syslog(LOG_ERR, "hrStorageTable: getfsstat() failed: %m");
                return; /* out of luck this time */
        }

        if (mounted_fs_count != (int)fs_buf_count || fs_buf == NULL) {
                fs_buf_count = mounted_fs_count;
                fs_buf = reallocf(fs_buf, fs_buf_count * sizeof(struct statfs));
                if (fs_buf == NULL) {
                        fs_buf_count = 0;
                        assert(0);
                        return;
                }
        }

        if ((mounted_fs_count = getfsstat(fs_buf,
            fs_buf_count * sizeof(struct statfs), MNT_NOWAIT)) < 0) {
                syslog(LOG_ERR, "hrStorageTable: getfsstat() failed: %m");
                return; /* out of luck this time */
        }

        HRDBG("got %d mounted FS", mounted_fs_count);

        fs_tbl_pre_refresh();

        for (i = 0; i < mounted_fs_count; i++) {
                snprintf(fs_string, sizeof(fs_string),
                    "%s, type: %s, dev: %s", fs_buf[i].f_mntonname,
                    fs_buf[i].f_fstypename, fs_buf[i].f_mntfromname);

                entry = storage_find_by_name(fs_string);
                if (entry == NULL)
                        entry = storage_entry_create(fs_string);

                assert (entry != NULL);
                if (entry == NULL)
                        return; /* Out of luck */

                entry->flags |= HR_STORAGE_FOUND;
                entry->type = fs_get_type(&fs_buf[i]); /*XXX - This is wrong*/

                units = fs_buf[i].f_bsize;
                size = fs_buf[i].f_blocks;
                used = fs_buf[i].f_blocks - fs_buf[i].f_bfree;
                while (size > INT_MAX) {
                        units <<= 1;
                        size >>= 1;
                        used >>= 1;
                }
                entry->allocationUnits = units;
                entry->size = size;
                entry->used = used;

                entry->allocationFailures = 0;

                /* take care of hrFSTable */
                fs_tbl_process_statfs_entry(&fs_buf[i], entry->index);
        }

        fs_tbl_post_refresh();
}

/**
 * Initialize storage table and populate it.
 */
void
init_storage_tbl(void)
{
        if ((mt_list = memstat_mtl_alloc()) == NULL)
                syslog(LOG_ERR,
                    "hrStorageTable: memstat_mtl_alloc() failed: %m");

        refresh_storage_tbl(1);
}

void
fini_storage_tbl(void)
{
        struct storage_map_entry *n1;

        if (swap_devs != NULL) {
                free(swap_devs);
                swap_devs = NULL;
        }
        swap_devs_len = 0;

        if (fs_buf != NULL) {
                free(fs_buf);
                fs_buf = NULL;
        }
        fs_buf_count = 0;

        while ((n1 = STAILQ_FIRST(&storage_map)) != NULL) {
                STAILQ_REMOVE_HEAD(&storage_map, link);
                if (n1->entry != NULL) {
                        TAILQ_REMOVE(&storage_tbl, n1->entry, link);
                        free(n1->entry->descr);
                        free(n1->entry);
                }
                free(n1->a_name);
                free(n1);
        }
        assert(TAILQ_EMPTY(&storage_tbl));
}

void
refresh_storage_tbl(int force)
{
        struct storage_entry *entry, *entry_tmp;

        if (!force && storage_tick != 0 &&
            this_tick - storage_tick < storage_tbl_refresh) {
                HRDBG("no refresh needed");
                return;
        }

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

        storage_OS_get_vm();
        storage_OS_get_swap();
        storage_OS_get_fs();
        storage_OS_get_memstat();

        /*
         * Purge items that disappeared
         */
        TAILQ_FOREACH_SAFE(entry, &storage_tbl, link, entry_tmp)
                if (!(entry->flags & HR_STORAGE_FOUND))
                        storage_entry_delete(entry);

        storage_tick = this_tick;

        HRDBG("refresh DONE");
}

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

        refresh_storage_tbl(0);

        switch (curr_op) {

        case SNMP_OP_GETNEXT:
                if ((entry = NEXT_OBJECT_INT(&storage_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(&storage_tbl,
                    &value->var, sub)) == NULL)
                        return (SNMP_ERR_NOSUCHNAME);
                goto get;

        case SNMP_OP_SET:
                if ((entry = FIND_OBJECT_INT(&storage_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_hrStorageIndex:
                value->v.integer = entry->index;
                return (SNMP_ERR_NOERROR);

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

        case LEAF_hrStorageDescr:
                assert(entry->descr != NULL);
                return (string_get(value, entry->descr, -1));
                break;

        case LEAF_hrStorageAllocationUnits:
                value->v.integer = entry->allocationUnits;
                return (SNMP_ERR_NOERROR);

        case LEAF_hrStorageSize:
                value->v.integer = entry->size;
                return (SNMP_ERR_NOERROR);

        case LEAF_hrStorageUsed:
                value->v.integer = entry->used;
                return (SNMP_ERR_NOERROR);

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