memory.c

snmp的源代码,已经在我的ubuntu下编译通过

        case memtotal:
            return *(mem_total);
        case memfree:
            return *(mem_free);
        case memshared:
            return *(mem_shared);
        case buffers:
            return *(mem_buffers);
        case cached:
            return *(mem_cached);
        case swaptotal:
            return *(swap_total);
        case swapfree:
            return *(swap_free);
        default:
            return -1;
    }
}

#else
#define pagetok(size) ((size) << pageshift)
#endif

#define SWAPGETLEFT 0
#define SWAPGETTOTAL 1

static long
getswap(int rettype)
{
    long            spaceleft = 0, spacetotal = 0;

#if defined(linux)
    spaceleft = memory(swapfree);
    spacetotal = memory(swaptotal);
#elif defined(bsdi2)
    struct swapstats swapst;
    size_t          size = sizeof(swapst);
    static int      mib[] = { CTL_VM, VM_SWAPSTATS };
    if (sysctl(mib, 2, &swapst, &size, NULL, 0) < 0)
        return (0);
    spaceleft = swapst.swap_free / 2;
    spacetotal = swapst.swap_total / 2;
#elif defined (hpux10) || defined(hpux11)
    struct pst_swapinfo pst_buf;
    int ndx = 0;
    long pgs, pgs_free;
  
    while (pstat_getswap(&pst_buf, sizeof(struct pst_swapinfo), 1, ndx) > 0) {
        if (pst_buf.pss_flags & SW_BLOCK) {
            pgs = pst_buf.pss_nblksenabled;
            pgs_free = pst_buf.pss_nblksavail;
        }
        else if (pst_buf.pss_flags & SW_FS) {
            pgs = pst_buf.pss_limit;
            pgs_free = pgs - pst_buf.pss_allocated - pst_buf.pss_reserve;
            /*
             * the following calculation is done this way to avoid integer overflow!
             * pss_swapchunk is either 512 or a multiple of 1024!
             */
            if (pst_buf.pss_swapchunk == 512) {
                pgs_free /= 2;
                pgs /= 2;
            } else {
                pgs_free *= (pst_buf.pss_swapchunk / 1024);
                pgs *= (pst_buf.pss_swapchunk / 1024);
            }
        }
        else {
            pgs = pgs_free = 0;
        }
        spaceleft += pgs_free;
        spacetotal += pgs;
        ndx = pst_buf.pss_idx + 1;
    }
#else /* !linux && !bsdi2 && !hpux10 && !hpux11 */
    struct swdevt   swdevt[100];
    struct fswdevt  fswdevt[100];
    FILE           *file;
    struct extensible ex;
    int             i, fd;
    char           *cp;

    if (auto_nlist
        (SWDEVT_SYMBOL, (char *) swdevt, sizeof(struct swdevt) * nswapdev)
        == 0)
        return (0);
    DEBUGMSGTL(("ucd-snmp/memory", "%d block swap devices: \n", nswapdev));
    for (i = 0; i < nswapdev; i++) {
        DEBUGMSGTL(("ucd-snmp/memory", "swdevt[%d]: %d\n", i,
                    swdevt[i].sw_enable));
        if (swdevt[i].sw_enable)
        {
#ifdef STRUCT_SWDEVT_HAS_SW_NBLKSENABLED
            DEBUGMSGTL(("ucd-snmp/memory",
                        "  swdevt.sw_nblksenabled:     %d\n",
                        swdevt[i].sw_nblksenabled));
            spacetotal += swdevt[i].sw_nblksenabled;
#else
            DEBUGMSGTL(("ucd-snmp/memory", "  swdevt.sw_nblks:     %d\n",
                        swdevt[i].sw_nblks));
            spacetotal += swdevt[i].sw_nblks;
#endif
            DEBUGMSGTL(("ucd-snmp/memory", "  swdevt.sw_nfpgs:     %d\n",
                        swdevt[i].sw_nfpgs));
            spaceleft += (swdevt[i].sw_nfpgs * 4);
        }
    }
    if (auto_nlist
        (FSWDEVT_SYMBOL, (char *) fswdevt,
         sizeof(struct fswdevt) * nswapfs)
        == 0)
        return (0);
    DEBUGMSGTL(("ucd-snmp/memory", "%d fs swap devices: \n", nswapfs));
    for (i = 0; i < nswapfs; i++) {
        DEBUGMSGTL(("ucd-snmp/memory", "fswdevt[%d]: %d\n", i,
                    fswdevt[i].fsw_enable));
        if (fswdevt[i].fsw_enable)
        {
            spacetotal += (fswdevt[i].fsw_limit * 2048);        /* 2048=bytes per page? */
            spaceleft += (fswdevt[i].fsw_limit * 2048 -
                          ((fswdevt[i].fsw_allocated -
                            fswdevt[i].fsw_min) * 37));
            DEBUGMSGTL(("ucd-snmp/memory",
                        "  fswdevt[i].fsw_limit:     %d\n",
                        fswdevt[i].fsw_limit));
            DEBUGMSGTL(("ucd-snmp/memory",
                        "  fswdevt[i].fsw_allocated: %d\n",
                        fswdevt[i].fsw_allocated));
            DEBUGMSGTL(("ucd-snmp/memory",
                        "  fswdevt[i].fsw_min:       %d\n",
                        fswdevt[i].fsw_min));
            DEBUGMSGTL(("ucd-snmp/memory",
                        "  fswdevt[i].fsw_reserve:   %d\n",
                        fswdevt[i].fsw_reserve));
            /*
             * 37 = calculated value I know it makes no sense, nor is it accurate 
             */
        }
    }
    /*
     * this is a real hack.  I need to get the hold info from swapinfo, but
     * I can't figure out how to read it out of the kernel directly
     * -- Wes 
     */
    strcpy(ex.command, "/etc/swapinfo -h");
    if ((fd = get_exec_output(&ex)) != -1) {
        file = fdopen(fd, "r");
        for (i = 1;
             i <= 2 && fgets(ex.output, sizeof(ex.output), file) != NULL;
             i++);
        if (fgets(ex.output, sizeof(ex.output), file) != NULL) {
            cp = skip_white(ex.output); /* not there should be any */
            cp = skip_not_white(cp);    /* skip over "reserve" */
            cp = skip_white(cp);
            cp = skip_not_white(cp);    /* avail swap, a '-' in most cases */
            cp = skip_white(cp);
            spaceleft -= atoi(cp);      /* reserved swap */
        }
        fclose(file);
        wait_on_exec(&ex);
    } else {
        return (0);
    }
#endif                          /* !linux && !bsdi2 && !hpux10 && !hpux11 */

    switch (rettype) {
    case SWAPGETLEFT:
        return (spaceleft);
    case SWAPGETTOTAL:
        return (spacetotal);
    }
    return 0;
}

static
unsigned char  *
var_extensible_mem(struct variable *vp,
                   oid * name,
                   size_t * length,
                   int exact,
                   size_t * var_len, WriteMethod ** write_method)
{

    static long     long_ret;
    static char     errmsg[1024];
#if !defined(linux)
#if defined(hpux10) || defined(hpux11)
    struct pst_dynamic pst_buf;
#elif defined(TOTAL_MEMORY_SYMBOL) || defined(USE_SYSCTL_VM)
    struct vmtotal total;
#endif
#endif

    long_ret = 0;               /* set to 0 as default */

    if (header_generic(vp, name, length, exact, var_len, write_method))
        return (NULL);

#if !defined(linux)
#if defined(hpux10) || defined(hpux11)
    if (pstat_getdynamic(&pst_buf, sizeof(struct pst_dynamic), 1, 0) < 0)
        return NULL;
#elif defined(USE_SYSCTL_VM)
    /*
     * sum memory statistics 
     */
    {
        size_t          size = sizeof(total);
        static int      mib[] = { CTL_VM, VM_TOTAL };
        if (sysctl(mib, 2, &total, &size, NULL, 0) < 0)
            return NULL;
    }
#elif defined(TOTAL_MEMORY_SYMBOL)
    if (auto_nlist(TOTAL_MEMORY_SYMBOL, (char *) &total, sizeof(total)) ==
        0)
        return NULL;
#endif
#endif                          /* !linux */

    switch (vp->magic) {
    case MIBINDEX:
        long_ret = 0;
        return ((u_char *) (&long_ret));
    case ERRORNAME:            /* dummy name */
        sprintf(errmsg, "swap");
        *var_len = strlen(errmsg);
        return ((u_char *) (errmsg));
    case MEMTOTALSWAP:
        long_ret = getswap(SWAPGETTOTAL);
        return ((u_char *) (&long_ret));
    case MEMAVAILSWAP:
        long_ret = getswap(SWAPGETLEFT);
        return ((u_char *) (&long_ret));
    case MEMSWAPMINIMUM:
        long_ret = minimumswap;
        return ((u_char *) (&long_ret));
    case MEMTOTALREAL:
#if defined(USE_SYSCTL)
        {
            size_t          size = sizeof(long_ret);
            static int      mib[] = { CTL_HW, HW_PHYSMEM };
            if (sysctl(mib, 2, &long_ret, &size, NULL, 0) < 0)
                return NULL;
            long_ret = long_ret / 1024;
        }
#elif defined(hpux10) || defined(hpux11)
        {
            struct pst_static pst_buf;
            if (pstat_getstatic(&pst_buf, sizeof(struct pst_static), 1, 0)
                < 0)
                return NULL;
            long_ret =
                pst_buf.physical_memory * (pst_buf.page_size / 1024);
        }
#elif defined(linux)
        long_ret = memory(memtotal);
#elif defined(_SC_PHYS_PAGES) && defined(_SC_PAGESIZE)
        long_ret =
            sysconf(_SC_PHYS_PAGES) * (sysconf(_SC_PAGESIZE) / 1024);
#elif defined(PHYSMEM_SYMBOL)
        {
            int             result;
            if (auto_nlist
                (PHYSMEM_SYMBOL, (char *) &result, sizeof(result)) == 0)
                return NULL;
            long_ret = result * 1000;   /* ??? */
        }
#else
        return NULL;            /* no dummy values */
#endif
        return ((u_char *) (&long_ret));
    case MEMAVAILREAL:
#ifdef linux
        long_ret = memory(memfree);
#elif defined(hpux10) || defined(hpux11)
        long_ret = pagetok((int) pst_buf.psd_arm);
#elif defined(TOTAL_MEMORY_SYMBOL) || defined(USE_SYSCTL_VM)
        long_ret = pagetok((int) total.t_arm);
#else
        return NULL;            /* no dummy values */
#endif
        return ((u_char *) (&long_ret));
#ifndef linux
    case MEMTOTALSWAPTXT:
#if defined(hpux10) || defined(hpux11)
        long_ret = pagetok((int) pst_buf.psd_vmtxt);
#elif !defined(bsdi2)
        long_ret = pagetok(total.t_vmtxt);
#else
        return NULL;            /* no dummy values */
#endif
        return ((u_char *) (&long_ret));
    case MEMUSEDSWAPTXT:
#if defined(hpux10) || defined(hpux11)
        long_ret = pagetok((int) pst_buf.psd_avmtxt);
#elif !defined(bsdi2)
        long_ret = pagetok(total.t_avmtxt);
#else
        return NULL;            /* no dummy values */
#endif
        return ((u_char *) (&long_ret));
    case MEMTOTALREALTXT:
#if defined(hpux10) || defined(hpux11)
        long_ret = pagetok((int) pst_buf.psd_rmtxt);
#elif !defined(bsdi2)
        long_ret = pagetok(total.t_rmtxt);
#else
        return NULL;            /* no dummy values */
#endif
        return ((u_char *) (&long_ret));
    case MEMUSEDREALTXT:
#if defined(hpux10) || defined(hpux11)
        long_ret = pagetok((int) pst_buf.psd_armtxt);
#elif !defined(bsdi2)
        long_ret = pagetok(total.t_armtxt);
#else
        return NULL;            /* no dummy values */
#endif
        return ((u_char *) (&long_ret));
#endif                          /* linux */
    case MEMTOTALFREE:
#ifdef linux
        long_ret = memory(memfree) + memory(swapfree);
#elif defined(hpux10) || defined(hpux11)
        long_ret = pagetok((int) pst_buf.psd_free);
#else
        long_ret = pagetok(total.t_free);
#endif
        return ((u_char *) (&long_ret));
    case MEMCACHED:
#ifdef linux
        long_ret = memory(cached);
#else
        return NULL;            /* no dummy values */
#endif
        return ((u_char *) (&long_ret));
    case MEMBUFFER:
#ifdef linux
        long_ret = memory(buffers);
#else
        return NULL;            /* no dummy values */
#endif
        return ((u_char *) (&long_ret));
    case MEMSHARED:
#ifdef linux
        long_ret = memory(memshared);
#else
        return NULL;            /* no dummy values */
#endif
        return ((u_char *) (&long_ret));
    case ERRORFLAG:
        long_ret = getswap(SWAPGETLEFT);
        long_ret = (long_ret > minimumswap) ? 0 : 1;
        return ((u_char *) (&long_ret));
    case ERRORMSG:
        long_ret = getswap(SWAPGETLEFT);
        if ((long_ret > minimumswap) ? 0 : 1)
            sprintf(errmsg, "Running out of swap space (%ld)",
                    getswap(SWAPGETLEFT));
        else
            errmsg[0] = 0;
        *var_len = strlen(errmsg);
        return ((u_char *) (errmsg));
    }
    return NULL;
}