vmstat_dynix.c

snmp的源代码,已经在我的ubuntu下编译通过

/*
 *  vmstat_dynix.c
 *  UCD SNMP module for systemStats section of UCD-SNMP-MIB for Dynix
 *  Patrick Hess <[e-mail]>
 *
 *  This is just a port of the vmstat_solaris2 code Version 0.7
 *
 */

/*
 * To make lint skip the debug code and stop complaining 
 */
#ifdef __lint
#define SNMP_NO_DEBUGGING 1
#endif

#define __NO_ASM_MACRO 1

/*
 * Includes start here 
 */
#include <net-snmp/net-snmp-config.h>

/*
 * Standard includes 
 */
#include <sys/tmp_ctl.h>
#include <sys/sysperf.h>
#include <sys/vmmeter.h>
#include <unistd.h>
#include <string.h>

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

#include "mibdefs.h"
#include "util_funcs.h"

/*
 * Header file for this module 
 */
#include "vmstat.h"
#include "vmstat_dynix.h"

/*
 * Includes end here 
 */


/*
 * Global structures start here 
 */

/*
 * A structure to save data gathered from the kernel kstat interface to.  
 */
/*
 * We used to have the sys/sysinfo.h cpu_stat_t here but we did not need 
 */
/*
 * all of it, some in a different size and some additional ones so we build 
 */
/*
 * our own 
 */
struct cpu_stat_snapshot {
    time_t          css_time;
    unsigned int    css_cpus;
    unsigned long long css_swapin;
    unsigned long long css_swapout;
    unsigned long long css_blocks_read;
    unsigned long long css_blocks_write;
    unsigned long long css_interrupts;
    unsigned long long css_context_sw;
    unsigned long long css_cpu[V_CPU_STATES];
};

/*
 * Global structures end here 
 */


/*
 * Global variables start here 
 */

/*
 * Variables for the calculated values, filled in update_stats    
 */
/*
 * Need to be global since we need them in more than one function 
 */
static ulong    swapin;
static ulong    swapout;
static ulong    blocks_read;
static ulong    blocks_write;
static ulong    interrupts;
static ulong    context_sw;

/*
 * Since MIB wants V_CPU_SYSTEM, which is V_CPU_KERNEL + V_CPU_STREAM 
 */
static long     cpu_perc[V_CPU_STATES + 1];

/*
 * How many snapshots we have already taken, needed for the first 
 */
/*
 * POLL_INTERVAL * POLL_VALUES seconds of agent running 
 */
static unsigned int number_of_snapshots;

/*
 * The place to store the snapshots of system data in 
 */
static struct cpu_stat_snapshot snapshot[POLL_VALUES + 1];

/*
 * And one for the raw counters, which we fill when the raw values are 
 */
/*
 * requested, as opposed to the absolute values, which are taken every 
 */
/*
 * POLL_INTERVAL seconds and calculated over POLL_INTERVAL * POLL_VALUES time 
 */
static struct cpu_stat_snapshot raw_values;

/*
 * Global variables end here 
 */


/*
 * Functions start here 
 */

/*
 * Function prototype 
 */
static void     update_stats(unsigned int registrationNumber,
                             void *clientarg);
static int      take_snapshot(struct cpu_stat_snapshot *css);

/*
 * init_vmstat_dynix starts here 
 */
/*
 * Init function for this module, from prototype 
 */
/*
 * Defines variables handled by this module, defines root OID for 
 */
/*
 * this module and registers it with the agent 
 */

FindVarMethod var_extensible_vmstat;

void
init_vmstat_dynix(void)
{

    /*
     * Which variables do we service ? 
     */
    struct variable2 extensible_vmstat_variables[] = {
        {MIBINDEX, ASN_INTEGER, RONLY, var_extensible_vmstat, 1,
         {MIBINDEX}},
        {ERRORNAME, ASN_OCTET_STR, RONLY, var_extensible_vmstat, 1,
         {ERRORNAME}},
        {SWAPIN, ASN_INTEGER, RONLY, var_extensible_vmstat, 1, {SWAPIN}},
        {SWAPOUT, ASN_INTEGER, RONLY, var_extensible_vmstat, 1, {SWAPOUT}},
        {IOSENT, ASN_INTEGER, RONLY, var_extensible_vmstat, 1, {IOSENT}},
        {IORECEIVE, ASN_INTEGER, RONLY, var_extensible_vmstat, 1,
         {IORECEIVE}},
        {SYSINTERRUPTS, ASN_INTEGER, RONLY, var_extensible_vmstat, 1,
         {SYSINTERRUPTS}},
        {SYSCONTEXT, ASN_INTEGER, RONLY, var_extensible_vmstat, 1,
         {SYSCONTEXT}},
        {CPUUSER, ASN_INTEGER, RONLY, var_extensible_vmstat, 1, {CPUUSER}},
        {CPUSYSTEM, ASN_INTEGER, RONLY, var_extensible_vmstat, 1,
         {CPUSYSTEM}},
        {CPUIDLE, ASN_INTEGER, RONLY, var_extensible_vmstat, 1, {CPUIDLE}},
        {CPURAWUSER, ASN_COUNTER, RONLY, var_extensible_vmstat, 1,
         {CPURAWUSER}},
        {CPURAWSYSTEM, ASN_COUNTER, RONLY, var_extensible_vmstat, 1,
         {CPURAWSYSTEM}},
        {CPURAWIDLE, ASN_COUNTER, RONLY, var_extensible_vmstat, 1,
         {CPURAWIDLE}},
        {CPURAWWAIT, ASN_COUNTER, RONLY, var_extensible_vmstat, 1,
         {CPURAWWAIT}},
        {CPURAWKERNEL, ASN_COUNTER, RONLY, var_extensible_vmstat, 1,
         {CPURAWKERNEL}},
        {IORAWSENT, ASN_COUNTER, RONLY, var_extensible_vmstat, 1,
         {IORAWSENT}},
        {IORAWRECEIVE, ASN_COUNTER, RONLY, var_extensible_vmstat, 1,
         {IORAWRECEIVE}},
        /*
         * Future use: 
         */
        /*
         * {ERRORFLAG, ASN_INTEGER, RONLY, var_extensible_vmstat, 1, {ERRORFLAG }},
         * {ERRORMSG, ASN_OCTET_STR, RONLY, var_extensible_vmstat, 1, {ERRORMSG }}
         */
    };

    /*
     * Define the OID pointer to the top of the mib tree that we're 
     */
    /*
     * registering underneath 
     */
    oid             vmstat_variables_oid[] = { UCDAVIS_MIB, 11 };

    /*
     * register ourselves with the agent to handle our mib tree 
     */
    /*
     * LINTED Trust me, I know what I'm doing 
     */
    REGISTER_MIB("ucd-snmp/vmstat", extensible_vmstat_variables, variable2,
                 vmstat_variables_oid);

    /*
     * Start with some useful data 
     */
    update_stats(0, NULL);

    /*
     * update_stats is run every POLL_INTERVAL seconds using this routine 
     */
    /*
     * (see 'man snmp_alarm') 
     */
    /*
     * This is only executed once to get some useful data in the beginning 
     */
    if (snmp_alarm_register(5, NULL, update_stats, NULL) == 0) {
        snmp_log(LOG_WARNING,
                 "vmstat_dynix (init): snmp_alarm_register failed.\n");
    }
    /*
     * This is the one that runs update_stats every POLL_INTERVAL seconds 
     */
    if (snmp_alarm_register(POLL_INTERVAL, SA_REPEAT, update_stats, NULL)
        == 0) {
        snmp_log(LOG_ERR,
                 "vmstat_dynix (init): snmp_alarm_register failed, cannot service requests.\n");
    }

}                               /* init_vmstat_dynix ends here */

/*
 * Data collection function take_snapshot starts here 
 */
/*
 * Get data from kernel and save into the snapshot strutcs 
 */
/*
 * Argument is the snapshot struct to save to. Global anyway, but looks nicer 
 */
static int
take_snapshot(struct cpu_stat_snapshot *css)
{
    /*
     * Variables start here 
     */

    /*
     * Counters 
     */
    unsigned int    cpu_num = 0;

    /*
     * Low resolution time counter 
     */
    time_t          current_time;

    /*
     * see sys/sysperf.h, holds CPU data 
     */
    exp_vmmeter_t  *cs, *origcs = 0;

    /*
     * size of the cs struct 
     */
    size_t          vminfo_size;

    /*
     * The usual stuff to count on, err, by 
     */
    int             i;
    int             engnum = 0;

    /*
     * Variables end here 
     */

    /*
     * Function starts here 
     */

    /*
     * Get time 
     */
    current_time = time(0);

    /*
     * If we have just gotten the data, return the values from last run (skip if-clause) 
     */
    /*
     * This happens on a snmpwalk request. 
     */
    /*
     * if we just did it less than 2 seconds ago 
     */
    /*
     * Jumps into if-clause either when snapshot is empty or when too old 
     */

    if ((css->css_time == 0) || (current_time > css->css_time + 2)) {
        /*
         * Make sure we clean up before we put new data into snapshot 
         */
        memset(css, 0, sizeof *css);

        /*
         * Get the number of CPUs we gather data from 
         */
        if ((cpu_num = tmp_ctl(TMP_NENG, 0)) < 0) {
            snmp_log(LOG_ERR,
                     "vmstat_dynix: (take snapshot) bad tmp_ctl return\n");
            return (-1);
        }
        css->css_cpus = cpu_num;

        vminfo_size = cpu_num * sizeof(exp_vmmeter_t);

        if (!(cs = (exp_vmmeter_t *) malloc(vminfo_size))) {
            snmp_log(LOG_ERR,
                     "vmstat_dynix: (take_snapshot) bad malloc return\n");
            return (-1);
        }
        origcs = cs;

        /*
         * Update timer 
         */
        css->css_time = current_time;

        /*
         * Read data from kernel into cs structure 
         */
        /*
         * cs is the buffer we are writing to and 
         */
        /*
         * vminfo_size is the size of the cs struct 
         */
        if ((getkerndata(VMMETER_DATAID, cs, vminfo_size)) < 0) {
            snmp_log(LOG_ERR,
                     "vmstat_dynix (take_snapshot): getkerndata failure.");
            return (-1);
        }

        /*
         * Get the data from each CPU 
         */
        /*
         * We walk through the whole vmmeter struct and sum up all the found stats, 
         */
        /*
         * there's one for every CPU in a machine 
         */
        /*
         * Okay...  you can't laugh at this!  I'm a C-hack, not a C-coder. :)  
         */
        while (engnum < cpu_num) {

            /*
             * Get the data from the cs structure and sum it up in our own structure 
             */
            css->css_swapin += (unsigned long long) cs->v_swpin;
            css->css_swapout += (unsigned long long) cs->v_swpout;
            css->css_blocks_read += (unsigned long long) cs->v_phread;
            css->css_blocks_write += (unsigned long long) cs->v_phwrite;
            css->css_interrupts += (unsigned long long) cs->v_intr;
            css->css_context_sw += (unsigned long long) cs->v_swtch;

            /*
             * We need a for-loop for the CPU STATE values 
             */
            for (i = 0; i < V_CPU_STATES; i++) {
                css->css_cpu[i] += (unsigned long long) cs->v_time[i];
            }                   /* end for */