/*
 * snmpdf.c - display disk space usage on a network entity via SNMP.
 *
 */

/* Portions of this file are subject to the following copyright(s).  See
 * the Net-SNMP's COPYING file for more details and other copyrights
 * that may apply:
 */
/***********************************************************************
	Copyright 1988, 1989, 1991, 1992 by Carnegie Mellon University

                      All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in 
supporting documentation, and that the name of CMU not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.  

CMU DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
CMU BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.
******************************************************************/
/*
 * Portions of this file are copyrighted by:
 * Copyright  2003 Sun Microsystems, Inc. All rights reserved.
 * Use is subject to license terms specified in the COPYING file
 * distributed with the Net-SNMP package.
 */
#include <net-snmp/net-snmp-config.h>

#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#include <sys/types.h>
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#include <stdio.h>
#include <ctype.h>
#if TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif

#include <net-snmp/net-snmp-includes.h>

void
usage(void)
{
    fprintf(stderr, "Usage: snmpdf [-Cu] ");
    snmp_parse_args_usage(stderr);
    fprintf(stderr, "\n\n");
    snmp_parse_args_descriptions(stderr);
    fprintf(stderr, "\nsnmpdf options:\n");
    fprintf(stderr,
            "\t-Cu\tUse UCD-SNMP dskTable to do the calculations.\n");
    fprintf(stderr,
            "\t\t[Normally the HOST-RESOURCES-MIB is consulted first.]\n");
    fprintf(stderr,
            "\t-Ch\tPrint using human readable format (MiB, GiB, TiB)\n");
    fprintf(stderr,
            "\t-CH\tPrint using human readable SI format (MB, GB, TB)\n");
}

int             ucd_mib = 0;
int             human_units = 0;

static void
optProc(int argc, char *const *argv, int opt)
{
    switch (opt) {
    case 'C':
        while (*optarg) {
            switch (*optarg++) {
            case 'u':
                ucd_mib = 1;
                break;
            case 'h':
                human_units = 1024;
                break;
            case 'H':
                human_units = 1000;
                break;
            default:
                fprintf(stderr,
                        "Unknown flag passed to -C: %c\n", optarg[-1]);
                exit(1);
            }
        }
    }
}

struct hrStorageTable {
    u_long          hrStorageIndex;
    oid            *hrStorageType;
    char           *hrStorageDescr;
    u_long          hrStorageAllocationUnits;
    u_long          hrStorageSize;
    u_long          hrStorageUsed;
};

int
add(netsnmp_pdu *pdu, const char *mibnodename,
    oid * index, size_t indexlen)
{
    oid             base[MAX_OID_LEN];
    size_t          base_length = MAX_OID_LEN;

    memset(base, 0, MAX_OID_LEN * sizeof(oid));

    if (!snmp_parse_oid(mibnodename, base, &base_length)) {
        snmp_perror(mibnodename);
        fprintf(stderr, "couldn't find mib node %s, giving up\n",
                mibnodename);
        exit(1);
    }

    if (base_length + indexlen > sizeof(base) / sizeof(base[0])) {
        fprintf(stderr, "internal error for %s, giving up\n", mibnodename);
        exit(1);
    }

    if (index && indexlen) {
        memcpy(&(base[base_length]), index, indexlen * sizeof(oid));
        base_length += indexlen;
    }
    DEBUGMSGTL(("add", "created: "));
    DEBUGMSGOID(("add", base, base_length));
    DEBUGMSG(("add", "\n"));
    snmp_add_null_var(pdu, base, base_length);

    return base_length;
}

netsnmp_variable_list *
collect(netsnmp_session * ss, netsnmp_pdu *pdu,
        oid * base, size_t base_length)
{
    netsnmp_pdu    *response;
    int             running = 1;
    netsnmp_variable_list *saved = NULL, **vlpp = &saved;
    int             status;

    while (running) {
        /*
         * gotta catch em all, gotta catch em all! 
         */
        status = snmp_synch_response(ss, pdu, &response);
        if (status != STAT_SUCCESS || !response) {
            snmp_sess_perror("snmpdf", ss);
            exit(1);
        }
        if (response->errstat != SNMP_ERR_NOERROR) {
            fprintf(stderr, "snmpdf: Error in packet: %s\n",
                    snmp_errstring(response->errstat));
            exit(1);
        }
        if (snmp_oid_compare(response->variables->name,
                             SNMP_MIN(base_length,
                                      response->variables->name_length),
                             base, base_length) != 0)
            running = 0;
        else if (response->variables->type == SNMP_NOSUCHINSTANCE ||
                 response->variables->type == SNMP_NOSUCHOBJECT ||
                 response->variables->type == SNMP_ENDOFMIBVIEW)
            running = 0;
        else {
            /*
             * get response 
             */
            *vlpp = response->variables;
            (*vlpp)->next_variable = NULL;      /* shouldn't be any, but just in case */

            /*
             * create the next request 
             */
            pdu = snmp_pdu_create(SNMP_MSG_GETNEXT);
            snmp_add_null_var(pdu, (*vlpp)->name, (*vlpp)->name_length);

            /*
             * finish loop setup 
             */
            vlpp = &((*vlpp)->next_variable);
            response->variables = NULL; /* ahh, forget about it */
        }
        snmp_free_pdu(response);
    }
    return saved;
}



char *format_human(char *buf, size_t len, unsigned long mem, unsigned long scale)
{
    if (mem >= scale*scale*scale*scale)
        snprintf(buf, len, "%4.2fP%sB", (float)mem/(scale*scale*scale*scale),
		scale == 1024 ? "i" : "");
    else if (mem >= scale*scale*scale)
        snprintf(buf, len, "%4.2fT%sB", (float)mem/(scale*scale*scale),
		scale == 1024 ? "i" : "");
    else if (mem >= scale*scale)
        snprintf(buf, len, "%4.2fG%sB", (float)mem/(scale*scale),
		scale == 1024 ? "i" : "");
    else if (mem >= scale)
        snprintf(buf, len, "%4.2fM%sB", (float)mem/scale,
		scale == 1024 ? "i" : "");
    else
        snprintf(buf, len, "%4.2fkB", (float)mem);
    return buf;
}

/* Computes value*units/divisor in an overflow-proof way.
 */
unsigned long
convert_units(unsigned long value, size_t units, size_t divisor)
{
    return (unsigned long)((double)value * units / (double)divisor);
}


int
main(int argc, char *argv[])
{
    netsnmp_session session, *ss;
    netsnmp_pdu    *pdu;
    netsnmp_pdu    *response;
    int             arg;
    oid             base[MAX_OID_LEN];
    size_t          base_length;
    int             status;
    netsnmp_variable_list *saved = NULL, *vlp = saved, *vlp2;
    int             count = 0, exit_code = 1;

    SOCK_STARTUP;

    /*
     * get the common command line arguments 
     */
    switch (arg = snmp_parse_args(argc, argv, &session, "C:", optProc)) {
    case NETSNMP_PARSE_ARGS_ERROR:
        goto out;
    case NETSNMP_PARSE_ARGS_SUCCESS_EXIT:
        exit_code = 0;
        goto out;
    case NETSNMP_PARSE_ARGS_ERROR_USAGE:
        usage();
        goto out;
    default:
        break;
    }

    if (arg != argc) {
	fprintf(stderr, "snmpdf: extra argument: %s\n", argv[arg]);
	goto out;
    }

    /*
     * Open an SNMP session.
     */
    ss = snmp_open(&session);
    if (ss == NULL) {
        /*
         * diagnose snmp_open errors with the input netsnmp_session pointer 
         */
        snmp_sess_perror("snmpdf", &session);
        goto out;
    }

    if (human_units) {
        printf("%-18s %10s %10s %10s %5s\n", "Description", "Size",
           "Used", "Available", "Used%");
    }
    else {
        printf("%-18s %15s %15s %15s %5s\n", "Description", "Size (kB)",
           "Used", "Available", "Used%");
    }
    if (ucd_mib == 0) {
        /*
         * * Begin by finding all the storage pieces that are of
         * * type hrStorageFixedDisk, which is a standard disk.
         */
        pdu = snmp_pdu_create(SNMP_MSG_GETNEXT);
        base_length =
            add(pdu, "HOST-RESOURCES-MIB:hrStorageIndex", NULL, 0);
        memcpy(base, pdu->variables->name, base_length * sizeof(oid));

        vlp = collect(ss, pdu, base, base_length);

        while (vlp) {
            size_t          units;
            unsigned long   hssize, hsused;
            char            descr[SPRINT_MAX_LEN];
            int             len;

            pdu = snmp_pdu_create(SNMP_MSG_GET);

            add(pdu, "HOST-RESOURCES-MIB:hrStorageDescr",
                &(vlp->name[base_length]), vlp->name_length - base_length);
            add(pdu, "HOST-RESOURCES-MIB:hrStorageAllocationUnits",
                &(vlp->name[base_length]), vlp->name_length - base_length);
            add(pdu, "HOST-RESOURCES-MIB:hrStorageSize",
                &(vlp->name[base_length]), vlp->name_length - base_length);
            add(pdu, "HOST-RESOURCES-MIB:hrStorageUsed",
                &(vlp->name[base_length]), vlp->name_length - base_length);

            status = snmp_synch_response(ss, pdu, &response);
            if (status != STAT_SUCCESS || !response) {
                snmp_sess_perror("snmpdf", ss);
                goto close_session;
            }

            vlp2 = response->variables;
            if (vlp2->type == SNMP_NOSUCHINSTANCE) goto next;
            len = vlp2->val_len;
            if (len >= SPRINT_MAX_LEN) len = SPRINT_MAX_LEN-1;
            memcpy(descr, vlp2->val.string, len);
            descr[len] = '\0';

            vlp2 = vlp2->next_variable;
            if (vlp2->type == SNMP_NOSUCHINSTANCE) goto next;
            units = vlp2->val.integer ? *(vlp2->val.integer) : 0;

            vlp2 = vlp2->next_variable;
            if (vlp2->type == SNMP_NOSUCHINSTANCE) goto next;
            hssize = vlp2->val.integer ? *(vlp2->val.integer) : 0;

            vlp2 = vlp2->next_variable;
            if (vlp2->type == SNMP_NOSUCHINSTANCE) goto next;
            hsused = vlp2->val.integer ? *(vlp2->val.integer) : 0;

            if (human_units) {
                char size[10], used[10], avail[10];
                printf("%-18s %10s %10s %10s %4lu%%\n", descr,
                    format_human(size, sizeof size,
                        units ? convert_units(hssize, units, 1024) : hssize, human_units),
                    format_human(used, sizeof used,
                        units ? convert_units(hsused, units, 1024) : hsused, human_units),
                    format_human(avail, sizeof avail,
                        units ? convert_units(hssize-hsused, units, 1024) : hssize -
                    hsused, human_units),
                    hssize ? convert_units(hsused, 100, hssize) : hsused);
            }
            else {
                printf("%-18s %15lu %15lu %15lu %4lu%%\n", descr,
                    units ? convert_units(hssize, units, 1024) : hssize,
                    units ? convert_units(hsused, units, 1024) : hsused,
                    units ? convert_units(hssize-hsused, units, 1024) : hssize -
                    hsused,
                    hssize ? convert_units(hsused, 100, hssize) : hsused);
            }

        next:
            vlp = vlp->next_variable;
            snmp_free_pdu(response);
            count++;
        }
    }

    if (count == 0) {
        /*
         * the host resources mib must not be supported.  Lets try the
         * UCD-SNMP-MIB and its dskTable 
         */

        pdu = snmp_pdu_create(SNMP_MSG_GETNEXT);
        base_length = add(pdu, "UCD-SNMP-MIB:dskIndex", NULL, 0);
        memcpy(base, pdu->variables->name, base_length * sizeof(oid));

        vlp = collect(ss, pdu, base, base_length);

        while (vlp) {
            unsigned long   hssize, hsused;
            char            descr[SPRINT_MAX_LEN];
            int             len;

            pdu = snmp_pdu_create(SNMP_MSG_GET);

            add(pdu, "UCD-SNMP-MIB:dskPath",
                &(vlp->name[base_length]), vlp->name_length - base_length);
            add(pdu, "UCD-SNMP-MIB:dskTotal",
                &(vlp->name[base_length]), vlp->name_length - base_length);
            add(pdu, "UCD-SNMP-MIB:dskUsed",
                &(vlp->name[base_length]), vlp->name_length - base_length);

            status = snmp_synch_response(ss, pdu, &response);
            if (status != STAT_SUCCESS || !response) {
                snmp_sess_perror("snmpdf", ss);
                goto close_session;
            }

            vlp2 = response->variables;
            if (vlp2->type == SNMP_NOSUCHINSTANCE) goto next2;
            len = vlp2->val_len;
            if (len >= SPRINT_MAX_LEN) len = SPRINT_MAX_LEN-1;
            memcpy(descr, vlp2->val.string, len);
            descr[len] = '\0';

            vlp2 = vlp2->next_variable;
            if (vlp2->type == SNMP_NOSUCHINSTANCE) goto next2;
            hssize = *(vlp2->val.integer);

            vlp2 = vlp2->next_variable;
            if (vlp2->type == SNMP_NOSUCHINSTANCE) goto next2;
            hsused = *(vlp2->val.integer);

            if (human_units) {
                char size[10], used[10], avail[10];
                printf("%-18s %10s %10s %10s %4lu%%\n", descr,
                    format_human(size, sizeof size, hssize, human_units),
                    format_human(used, sizeof used, hsused, human_units),
                    format_human(avail, sizeof avail, hssize - hsused, human_units),
                    hssize ? convert_units(hsused, 100, hssize) : hsused);
            }
            else {
                printf("%-18s %15lu %15lu %15lu %4lu%%\n", descr,
                     hssize, hsused, hssize - hsused,
                     hssize ? convert_units(hsused, 100, hssize) : hsused);
            }

        next2:
            vlp = vlp->next_variable;
            snmp_free_pdu(response);
            count++;
        }
    }

    if (count == 0) {
        fprintf(stderr, "Failed to locate any partitions.\n");
        goto close_session;
    }

    exit_code = 0;

close_session:
    snmp_close(ss);

out:
    SOCK_CLEANUP;
    return exit_code;
}                               /* end main() */