#define __USE_MINGW_ANSI_STDIO 0
#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-features.h>
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
#include <net-snmp/agent/hardware/fsys.h>
#include "hw_fsys.h"
#include "hardware/fsys/hw_fsys_private.h"
#ifdef HAVE_INTTYPES_H
#include <inttypes.h>
#endif
#if defined(HAVE_PCRE_H)
#include <pcre.h>
#elif defined(HAVE_REGEX_H)
#include <sys/types.h>
#include <regex.h>
#endif

netsnmp_feature_child_of(hw_fsys_get_container, netsnmp_unused);

static int _fsysAutoUpdate = 0;   /* 0 means on-demand caching */

static netsnmp_cache     *_fsys_cache;
static netsnmp_container *_fsys_container;
static int         _fsys_idx;

static void _parse_mount_config(const char *, char *);
static void _free_mount_config(void);

conf_mount_list *ignoremount_list;

/*
 * Architecture-independent processing of loading filesystem statistics
 */
static int
_fsys_load(void)
{
    netsnmp_fsys_arch_load();
    /* XXX - update cache timestamp */
    return 0;
}

/*
 * Architecture-independent release of filesystem statistics
 */
static void
_fsys_free(void)
{
    netsnmp_fsys_info *sp;

    for (sp = CONTAINER_FIRST(_fsys_container); sp;
         sp = CONTAINER_NEXT(_fsys_container, sp)) {
         sp->flags &= ~NETSNMP_FS_FLAG_ACTIVE;
    }
}

/*
 * Wrapper routine for automatically updating fsys information
 */
void
_fsys_update_stats(unsigned int clientreg, void *data)
{
    _fsys_free();
    _fsys_load();
}

void init_hw_fsys( void ) {

    if ( _fsys_container )
        return;   /* Already initialised */

    DEBUGMSGTL(("fsys", "Initialise Hardware FileSystem module\n"));

    /*
     * Define a container to hold the list of filesystems
     */
    _fsys_container = netsnmp_container_find("fsysTable:table_container");
    if ( NULL == _fsys_container ) {
        snmp_log( LOG_ERR, "failed to create container for fsysTable");
        return;
    }
    netsnmp_fsys_arch_init( );

    /*
     * If we're sampling the file system information automatically,
     *   then arrange for this to be triggered regularly.
     *
     * If we're not sampling these values regularly,
     *   create a suitable cache handler instead.
     */
    if ( _fsysAutoUpdate ) {
        DEBUGMSGTL(("fsys", "Reloading Hardware FileSystems automatically (%d)\n",
                               _fsysAutoUpdate));
        snmp_alarm_register( _fsysAutoUpdate, SA_REPEAT,
                             _fsys_update_stats, NULL );
    }
    else {
        _fsys_cache = netsnmp_cache_create( 5, netsnmp_fsys_load,
                                               netsnmp_fsys_free, NULL, 0 );
        DEBUGMSGTL(("fsys", "Reloading Hardware FileSystems on-demand (%p)\n",
                               _fsys_cache));
    }

    snmpd_register_config_handler("ignoremount", _parse_mount_config,
                                  _free_mount_config, "name");
}

void shutdown_hw_fsys( void ) {
    _fsys_free();
}

#ifndef NETSNMP_FEATURE_REMOVE_HW_FSYS_GET_CONTAINER
/*
 *  Return the main fsys container
 */
netsnmp_container *netsnmp_fsys_get_container( void ) { return _fsys_container; }
#endif /* NETSNMP_FEATURE_REMOVE_HW_FSYS_GET_CONTAINER */

/*
 *  Return the main fsys cache control structure (if defined)
 */
netsnmp_cache *netsnmp_fsys_get_cache( void ) { return _fsys_cache; }


/*
 * Wrapper routine for re-loading filesystem statistics on demand
 */
int
netsnmp_fsys_load( netsnmp_cache *cache, void *data )
{
    /* XXX - check cache timeliness */
    return _fsys_load();
}

/*
 * Wrapper routine for releasing expired filesystem statistics
 */
void
netsnmp_fsys_free( netsnmp_cache *cache, void *data )
{
    _fsys_free();
}


netsnmp_fsys_info *netsnmp_fsys_get_first(void) {
    return CONTAINER_FIRST(_fsys_container);
}

netsnmp_fsys_info *netsnmp_fsys_get_next(const netsnmp_fsys_info *this_ptr) {
    return CONTAINER_NEXT(_fsys_container, this_ptr);
}

netsnmp_fsys_info *
_fsys_create_entry(void)
{
    netsnmp_fsys_info *sp;

    sp = SNMP_MALLOC_TYPEDEF(netsnmp_fsys_info);
    if (!sp)
        return NULL;

    /*
     * Set up the index value.
     *
     * All this trouble, just for a simple integer.
     * Surely there must be a better way?
     */
    sp->idx.len  = 1;
    sp->idx.oids = SNMP_MALLOC_TYPEDEF( oid );
    sp->idx.oids[0] = ++_fsys_idx;

    DEBUGMSGTL(("fsys:new", "Create filesystem entry (index = %d)\n", _fsys_idx));
    CONTAINER_INSERT(_fsys_container, sp);
    return sp;
}

/*
 * Retrieve a filesystem entry based on the path where it is mounted,
 *  or (optionally) insert a new one into the container
 */
netsnmp_fsys_info *
netsnmp_fsys_by_path( char *path, int create_type )
{
    netsnmp_fsys_info *sp;

    DEBUGMSGTL(("fsys:path", "Get filesystem entry (%s)\n", path));

    /*
     *  Look through the list for a matching entry
     */
        /* .. or use a secondary index container ?? */
    for (sp = CONTAINER_FIRST( _fsys_container );
         sp;
         sp = CONTAINER_NEXT(  _fsys_container, sp )) {

        if ( !strcmp( path, sp->path ))
            return sp;
    }

    /*
     * Not found...
     */
    if ( create_type == NETSNMP_FS_FIND_EXIST ) {
        DEBUGMSGTL(("fsys:path", "No such filesystem entry\n"));
        return NULL;
    }

    /*
     * ... so let's create a new one
     */
    sp = _fsys_create_entry();
    if (sp)
        strlcpy(sp->path, path, sizeof(sp->path));
    return sp;
}


/*
 * Retrieve a filesystem entry based on the hardware device,
 *   (or exported path for remote mounts).
 * (Optionally) insert a new one into the container.
 */
netsnmp_fsys_info *
netsnmp_fsys_by_device( char *device, int create_type )
{
    netsnmp_fsys_info *sp;

    DEBUGMSGTL(("fsys:device", "Get filesystem entry (%s)\n", device));

    /*
     *  Look through the list for a matching entry
     */
        /* .. or use a secondary index container ?? */
    for (sp = CONTAINER_FIRST( _fsys_container );
         sp;
         sp = CONTAINER_NEXT(  _fsys_container, sp )) {

        if ( !strcmp( device, sp->device ))
            return sp;
    }

    /*
     * Not found...
     */
    if ( create_type == NETSNMP_FS_FIND_EXIST ) {
        DEBUGMSGTL(("fsys:device", "No such filesystem entry\n"));
        return NULL;
    }

    /*
     * ... so let's create a new one
     */
    sp = _fsys_create_entry();
    if (sp)
        strlcpy(sp->device, device, sizeof(sp->device));
    return sp;
}


/*
 *  Convert fsys size information to 1K units
 *    (attempting to avoid 32-bit overflow!)
 */
unsigned long long
_fsys_to_K( unsigned long long size, unsigned long long units )
{
    int factor = 1;

    if ( units == 0 ) {
        return 0;    /* XXX */
    } else if ( units == 1024 ) {
        return size;
    } else if ( units == 512 ) {      /* To avoid unnecessary division */
        return size/2;
    } else if ( units < 1024 ) {
        factor = 1024 / units;   /* Assuming power of two */
        return (size / factor);
    } else {
        factor = units / 1024;   /* Assuming multiple of 1K */
        return (size * factor);
    }
}

unsigned long long
netsnmp_fsys_size_ull(const netsnmp_fsys_info *f)
{
    if ( !f ) {
        return 0;
    }
    return _fsys_to_K( f->size, f->units );
}

unsigned long long
netsnmp_fsys_used_ull(const netsnmp_fsys_info *f)
{
    if ( !f ) {
        return 0;
    }
    return _fsys_to_K( f->used, f->units );
}

unsigned long long
netsnmp_fsys_avail_ull(const netsnmp_fsys_info *f)
{
    if ( !f ) {
        return 0;
    }
    return _fsys_to_K( f->avail, f->units );
}


int
netsnmp_fsys_size(const netsnmp_fsys_info *f)
{
    unsigned long long v = netsnmp_fsys_size_ull(f);
    return (int)v;
}

int
netsnmp_fsys_used(const netsnmp_fsys_info *f)
{
    unsigned long long v = netsnmp_fsys_used_ull(f);
    return (int)v;
}

int
netsnmp_fsys_avail(const netsnmp_fsys_info *f)
{
    unsigned long long v = netsnmp_fsys_avail_ull(f);
    return (int)v;
}

#ifndef INT32_MAX
#define INT32_MAX 0x7fffffff
#endif

#ifndef PRIu64
#define PRIu64 "llu"
#endif

/* recalculate f->size_32, used_32, avail_32 and units_32 from f->size & comp.*/
void
netsnmp_fsys_calculate32(netsnmp_fsys_info *f)
{
    unsigned long long s = f->size;
    unsigned shift = 0;

    while (s > INT32_MAX) {
        s = s >> 1;
        shift++;
    }

    f->size_32 = s;
    f->units_32 = f->units << shift;
    f->avail_32 = f->avail >> shift;
    f->used_32 = f->used >> shift;

    DEBUGMSGTL(("fsys", "Results of 32-bit conversion: size %" PRIu64 " -> %lu;"
		" units %" PRIu64 " -> %lu; avail %" PRIu64 " -> %lu;"
                " used %" PRIu64 " -> %lu\n",
		(uint64_t)f->size, f->size_32, (uint64_t)f->units, f->units_32,
		(uint64_t)f->avail, f->avail_32, (uint64_t)f->used, f->used_32));
}

static void
_parse_mount_config(const char *token, char *cptr)
{
    conf_mount_list *m_new;
    char            *name, *st = NULL;
#if defined(HAVE_PCRE_H)
    const char      *pcre_error;
    int             pcre_error_offset;
    int             is_regex = 0;
#elif defined(HAVE_REGEX_H)
    int             r = 0;
    int             is_regex = 0;
#endif

    name = strtok_r(cptr, " \t", &st);
    if (strcmp(name, "-r") == 0) {
#if defined(HAVE_PCRE_H) || defined(HAVE_REGEX_H)
        is_regex = 1;
        name = strtok_r(NULL, " \t", &st);
#else
        config_perror("Missing regex support");
        return;
#endif
    }
    m_new = SNMP_MALLOC_TYPEDEF(conf_mount_list);
    if (!m_new) {
        config_perror("Out of memory");
        goto err;
    }
    m_new->name = strdup(name);
    if (!m_new->name) {
        config_perror("Out of memory");
        goto err;
    }
#if defined(HAVE_PCRE_H)
    if (is_regex) {
        m_new->regex_ptr = pcre_compile(m_new->name, 0, &pcre_error,
                                        &pcre_error_offset, NULL);
        if (!m_new->regex_ptr) {
            config_perror(pcre_error);
            goto err;
        }
    }
#elif defined(HAVE_REGEX_H)
    if (is_regex) {
        m_new->regex_ptr = malloc(sizeof(regex_t));
        if (!m_new->regex_ptr) {
            config_perror("Out of memory");
            goto err;
        }
        r = regcomp(m_new->regex_ptr, m_new->name, REG_NOSUB);
        if (r) {
            char buf[BUFSIZ];
            size_t regerror_len = 0;

            regerror_len = regerror(r, m_new->regex_ptr, buf, BUFSIZ);
            if (regerror_len >= BUFSIZ)
                buf[BUFSIZ - 1] = '\0';
            else
                buf[regerror_len] = '\0';
            config_perror(buf);
            goto err;
        }
    }
#endif
    m_new->next = ignoremount_list;
    ignoremount_list = m_new;
    return;

err:
    if (m_new) {
#if defined(HAVE_PCRE_H) || defined(HAVE_REGEX_H)
        free(m_new->regex_ptr);
#endif
        free(m_new->name);
    }
    free (m_new);
}

static void
_free_mount_config(void)
{
    conf_mount_list *m_ptr = ignoremount_list, *m_next;
    while (m_ptr) {
        m_next = m_ptr->next;
#if defined(HAVE_PCRE_H) || defined(HAVE_REGEX_H)
        free(m_ptr->regex_ptr);
#endif
        free(m_ptr->name);
        free(m_ptr);
        m_ptr = m_next;
    }
    ignoremount_list = NULL;
}
