/*
 * disk.c
 */

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

#include <stdio.h>

#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
#include <signal.h>
#if HAVE_MACHINE_PARAM_H
#include <machine/param.h>
#endif
#if HAVE_SYS_VMMETER_H
#if !(defined(bsdi2) || defined(netbsd1))
#include <sys/vmmeter.h>
#endif
#endif
#if HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#if HAVE_SYS_CONF_H
#include <sys/conf.h>
#endif
#if HAVE_ASM_PAGE_H
#include <asm/page.h>
#endif
#if HAVE_SYS_SWAP_H
#include <sys/swap.h>
#endif
#if HAVE_SYS_FS_H
#include <sys/fs.h>
#else
#if HAVE_UFS_FS_H
#include <ufs/fs.h>
#else
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_SYS_VNODE_H
#include <sys/vnode.h>
#endif
#ifdef HAVE_UFS_UFS_QUOTA_H
#include <ufs/ufs/quota.h>
#endif
#ifdef HAVE_UFS_UFS_INODE_H
#include <ufs/ufs/inode.h>
#endif
#if HAVE_UFS_FFS_FS_H
#include <ufs/ffs/fs.h>
#endif
#endif
#endif
#if HAVE_MTAB_H
#include <mtab.h>
#endif
#include <sys/stat.h>
#include <errno.h>
#if HAVE_SYS_STATFS_H
#include <sys/statfs.h>
#endif
#if HAVE_SYS_STATVFS_H
#include <sys/statvfs.h>
#endif
#if HAVE_SYS_VFS_H
#include <sys/vfs.h>
#endif
#if defined(HAVE_STATFS)
#if HAVE_SYS_MOUNT_H
#include <sys/mount.h>
#endif
#if HAVE_SYS_SYSCTL_H
#include <sys/sysctl.h>
#endif
#if !defined(HAVE_STATVFS)
#define statvfs statfs
#endif
#endif
#if HAVE_VM_VM_H
#include <vm/vm.h>
#endif
#if HAVE_VM_SWAP_PAGER_H
#include <vm/swap_pager.h>
#endif
#if HAVE_SYS_FIXPOINT_H
#include <sys/fixpoint.h>
#endif
#if HAVE_MALLOC_H
#include <malloc.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#endif
#if HAVE_FSTAB_H
#include <fstab.h>
#endif
#if HAVE_MNTENT_H
#include <mntent.h>
#endif
#if HAVE_SYS_MNTTAB_H
#include <sys/mnttab.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if TIME_WITH_SYS_TIME
# ifdef WIN32
#  include <sys/timeb.h>
# else
#  include <sys/time.h>
# endif
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#if HAVE_WINSOCK_H
#include <winsock.h>
#endif

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

#include "struct.h"
#include "disk.h"
#include "util_funcs.h"
#if USING_UCD_SNMP_ERRORMIB_MODULE
#include "errormib.h"
#else
#define setPerrorstatus(x) snmp_log_perror(x)
#endif

/*
 *  * config file parsing routines
 *   */
static void       disk_free_config(void);
static void       disk_parse_config(const char *, char *);
static void       disk_parse_config_all(const char *, char *);
static void       find_and_add_allDisks(int minpercent);
static void       add_device(char *path, char *device,
	                     int minspace, int minpercent, int override);
static void       modify_disk_parameters(int index, int minspace,
	                                 int minpercent);
static int        disk_exists(char *path);
static char      *find_device(char *path);

struct diskpart {
    char            device[STRMAX];
    char            path[STRMAX];
    int             minimumspace;
    int             minpercent;
};

int             numdisks;
int             allDisksIncluded = 0;
int             maxdisks = 0;
struct diskpart *disks;

struct variable2 extensible_disk_variables[] = {
  {MIBINDEX, ASN_INTEGER, RONLY, var_extensible_disk, 1, {MIBINDEX}},
  {ERRORNAME, ASN_OCTET_STR, RONLY, var_extensible_disk, 1, {ERRORNAME}},
  {DISKDEVICE, ASN_OCTET_STR, RONLY, var_extensible_disk, 1,
   {DISKDEVICE}},
  {DISKMINIMUM, ASN_INTEGER, RONLY, var_extensible_disk, 1,
   {DISKMINIMUM}},
  {DISKMINPERCENT, ASN_INTEGER, RONLY, var_extensible_disk, 1,
   {DISKMINPERCENT}},
  {DISKTOTAL, ASN_INTEGER, RONLY, var_extensible_disk, 1, {DISKTOTAL}},
  {DISKAVAIL, ASN_INTEGER, RONLY, var_extensible_disk, 1, {DISKAVAIL}},
  {DISKUSED, ASN_INTEGER, RONLY, var_extensible_disk, 1, {DISKUSED}},
  {DISKPERCENT, ASN_INTEGER, RONLY, var_extensible_disk, 1,
   {DISKPERCENT}},
  {DISKPERCENTNODE, ASN_INTEGER, RONLY, var_extensible_disk, 1,
   {DISKPERCENTNODE}},
  {ERRORFLAG, ASN_INTEGER, RONLY, var_extensible_disk, 1, {ERRORFLAG}},
  {ERRORMSG, ASN_OCTET_STR, RONLY, var_extensible_disk, 1, {ERRORMSG}}
};

/*
 * Define the OID pointer to the top of the mib tree that we're
 * registering underneath 
 */
oid             disk_variables_oid[] = { NETSNMP_UCDAVIS_MIB, NETSNMP_DISKMIBNUM, 1 };

void
init_disk(void)
{
  /*
   * register ourselves with the agent to handle our mib tree 
   */
  REGISTER_MIB("ucd-snmp/disk", extensible_disk_variables, variable2,
	       disk_variables_oid);

  snmpd_register_config_handler("disk", disk_parse_config,
				disk_free_config,
				"path [ minspace | minpercent% ]");
  snmpd_register_config_handler("includeAllDisks", disk_parse_config_all,
				disk_free_config,
				"minpercent%");
  allDisksIncluded = 0;
}

static void
disk_free_config(void)
{
  int             i;

  numdisks = 0;
  for (i = 0; i < maxdisks; i++) {    /* init/erase disk db */
    disks[i].device[0] = 0;
    disks[i].path[0] = 0;
    disks[i].minimumspace = -1;
    disks[i].minpercent = -1;
  }
  allDisksIncluded = 0;
}

static void 
disk_parse_config(const char *token, char *cptr)
{
#if HAVE_FSTAB_H || HAVE_GETMNTENT || HAVE_STATFS
  char            tmpbuf[1024];
  char            path[STRMAX];
  int             minpercent;
  int             minspace;

  if (numdisks == maxdisks) {
      if (maxdisks == 0) {
          maxdisks = 50;
          disks = malloc(maxdisks * sizeof(struct diskpart));
          if (!disks) {
              config_perror("malloc failed for new disk allocation.");
              sprintf(tmpbuf, "\tignoring:  %s", cptr);
              tmpbuf[ sizeof(tmpbuf)-1 ] = 0;
              config_perror(tmpbuf);
              return;
          }
          memset(disks, 0, maxdisks * sizeof(struct diskpart));
      } else {
          maxdisks *= 2;
          disks = realloc(disks, maxdisks * sizeof(struct diskpart));
          if (!disks) {
              config_perror("malloc failed for new disk allocation.");
              sprintf(tmpbuf, "\tignoring:  %s", cptr);
              tmpbuf[ sizeof(tmpbuf)-1 ] = 0;
              config_perror(tmpbuf);
              return;
          }
          memset(disks + maxdisks/2, 0, maxdisks/2 * sizeof(struct diskpart));
      }
  }

  /*
   * read disk path (eg, /1 or /usr) 
   */
  copy_nword(cptr, path, sizeof(path));
  cptr = skip_not_white(cptr);
  cptr = skip_white(cptr);
	
  /*
   * read optional minimum disk usage spec 
   */
  if(cptr != NULL) {
      if(strchr(cptr, '%') == 0) {
          minspace = atoi(cptr);
          minpercent = -1;
      }
      else {
          minspace = -1;
          minpercent = atoi(cptr);
      }
  } else {
      minspace = NETSNMP_DEFDISKMINIMUMSPACE;
      minpercent = -1;
  }

  /*
   * check if the disk already exists, if so then modify its
   * parameters. if it does not exist then add it
   */
  add_device(path, find_device(path), minspace, minpercent, 1);
#endif /* HAVE_FSTAB_H || HAVE_GETMNTENT || HAVE_STATFS */
}

static void 
disk_parse_config_all(const char *token, char *cptr)
{
#if HAVE_FSTAB_H || HAVE_GETMNTENT || HAVE_STATFS
  char            tmpbuf[1024];
  int             minpercent = DISKMINPERCENT;
    
  if (numdisks == maxdisks) {
      if (maxdisks == 0) {
          maxdisks = 50;
          disks = malloc(maxdisks * sizeof(struct diskpart));
          if (!disks) {
              config_perror("malloc failed for new disk allocation.");
              sprintf(tmpbuf, "\tignoring:  %s", cptr);
              config_perror(tmpbuf);
              return;
          }
          memset(disks, 0, maxdisks * sizeof(struct diskpart));
      } else {
          maxdisks *= 2;
          disks = realloc(disks, maxdisks * sizeof(struct diskpart));
          if (!disks) {
              config_perror("malloc failed for new disk allocation.");
              sprintf(tmpbuf, "\tignoring:  %s", cptr);
              config_perror(tmpbuf);
              return;
          }
          memset(disks + maxdisks/2, 0, maxdisks/2 * sizeof(struct diskpart));
      }
  }
  /*
   * read the minimum disk usage percent
   */
  if(cptr != NULL) {
      if(strchr(cptr, '%') != 0) {
          minpercent = atoi(cptr);
      }
  }
  /*
   * if we have already seen the "includeAllDisks" directive
   * then search for the disk in the "disks" array and modify
   * the values. if we havent seen the "includeAllDisks"
   * directive then include this disk
   */
  if(allDisksIncluded) {
      config_perror("includeAllDisks already specified.");
      sprintf(tmpbuf, "\tignoring: includeAllDisks %s", cptr);
      config_perror(tmpbuf);
  }
  else {
      allDisksIncluded = 1;
      find_and_add_allDisks(minpercent);
  }
#endif /* HAVE_FSTAB_H || HAVE_GETMNTENT || HAVE_STATFS */
}


static void
add_device(char *path, char *device, int minspace, int minpercent, int override) 
{
  int index;

  if (!path || !strcmp(path, "none")) {
    DEBUGMSGTL(("ucd-snmp/disk", "Skipping null path device (%s)\n", device));
    return;
  }
  if (numdisks == maxdisks) {
      if (maxdisks == 0) {
          maxdisks = 50;
          disks = malloc(maxdisks * sizeof(struct diskpart));
          if (!disks) {
              char tmpbuf[1024];
              snprintf(tmpbuf, sizeof(tmpbuf), "\tignoring:  %s", device);
              tmpbuf[ sizeof(tmpbuf)-1 ] = 0;
              config_perror(tmpbuf);
              return;
          }
          memset(disks, 0, maxdisks * sizeof(struct diskpart));
      } else {
          maxdisks *= 2;
          disks = realloc(disks, maxdisks * sizeof(struct diskpart));
          if (!disks) {
              char tmpbuf[1024];
              config_perror("malloc failed for new disk allocation.");
              snprintf(tmpbuf, sizeof(tmpbuf), "\tignoring:  %s", device);
              tmpbuf[ sizeof(tmpbuf)-1 ] = 0;
              config_perror(tmpbuf);
              return;
          }
          memset(disks + maxdisks/2, 0, maxdisks/2 * sizeof(struct diskpart));
      }
  }

  index = disk_exists(path);
  if((index != -1) && (index < maxdisks) && (override==1)) {
    modify_disk_parameters(index, minspace, minpercent);
  }
  else if(index == -1){
    /* add if and only if the device was found */
    if(device[0] != 0) {
      copy_nword(path, disks[numdisks].path, 
		 sizeof(disks[numdisks].path));
      copy_nword(device, disks[numdisks].device, 
		 sizeof(disks[numdisks].device));
      disks[numdisks].minimumspace = minspace;
      disks[numdisks].minpercent   = minpercent;
      numdisks++;  
    }
    else {
      disks[numdisks].minimumspace = -1;
      disks[numdisks].minpercent = -1;
      disks[numdisks].path[0] = 0;
      disks[numdisks].device[0] = 0;
    }
  }
}

void
modify_disk_parameters(int index, int minspace, int minpercent)
{
  disks[index].minimumspace = minspace;
  disks[index].minpercent   = minpercent;
}

int disk_exists(char *path) 
{
  int index;
  for(index = 0; index < numdisks; index++) {
    DEBUGMSGTL(("ucd-snmp/disk", "Checking for %s. Found %s at %d\n", path, disks[index].path, index));
    if(strcmp(path, disks[index].path) == 0) {
      return index;
    }
  }
  return -1;
}

static void 
find_and_add_allDisks(int minpercent)
{
#if HAVE_GETMNTENT
#if HAVE_SYS_MNTTAB_H
  struct mnttab   mnttab;
#else
  struct mntent  *mntent;
#endif
  FILE           *mntfp;
#elif HAVE_FSTAB_H
  struct fstab   *fstab1;
#elif HAVE_STATFS
  struct statfs   statf;
#endif
#if defined(HAVE_GETMNTENT) && !defined(HAVE_SETMNTENT)
  int             i;
#endif

  int dummy = 0;
  char            tmpbuf[1024];
  /* 
   * find the device for the path and copy the device into the
   * string declared above and at the end of the routine return it
   * to the caller 
   */
#if HAVE_FSTAB_H || HAVE_GETMNTENT || HAVE_STATFS   
#if HAVE_GETMNTENT
#if HAVE_SETMNTENT
  mntfp = setmntent(ETC_MNTTAB, "r");
  while (NULL != (mntent = getmntent(mntfp))) {
    add_device(mntent->mnt_dir, mntent->mnt_fsname, -1, minpercent, 0);
    dummy = 1;
  }
  if (mntfp)
    endmntent(mntfp);
  if(dummy != 0) {
    /*
     * dummy clause for else below
     */
  }
#else                           /* getmentent but not setmntent */
  mntfp = fopen(ETC_MNTTAB, "r");
  while ((i = getmntent(mntfp, &mnttab)) == 0) {
    add_device(mnttab.mnt_mountp, mnttab.mnt_special, -1, minpercent, 0);
    dummy = 1;
  }
  fclose(mntfp);
  if(dummy != 0) {
    /*
     * dummy clause for else below
     */
  }
#endif /* HAVE_SETMNTENT */
#elif HAVE_FSTAB_H
  setfsent();			/* open /etc/fstab */
  while((fstab1 = getfsent()) != NULL) {
    add_device(fstab1->fs_file, fstab1->fs_spec, -1, minpercent, 0);
    dummy = 1;
  }
  endfsent();			/* close /etc/fstab */
  if(dummy != 0) {
    /*
     * dummy clause for else below
     */
  }
#elif HAVE_STATFS
  /*
   * since there is no way to get all the mounted systems with just
   * statfs we default to the root partition "/"
   */
  if (statfs("/", &statf) == 0) {
    add_device("/", statf.f_mntfromname, -1, minpercent, 0);
  }
#endif
  else {
    if (numdisks == maxdisks) {
      return;
    }
    snprintf(tmpbuf, sizeof(tmpbuf),
             "Couldn't find device for disk %s",
             disks[numdisks].path);
    tmpbuf[ sizeof(tmpbuf)-1 ] = 0;
    config_pwarn(tmpbuf);
    disks[numdisks].minimumspace = -1;
    disks[numdisks].minpercent = -1;
    disks[numdisks].path[0] = 0;
  }
#else
  config_perror("'disk' checks not supported on this architecture.");
#endif                   /* HAVE_FSTAB_H || HAVE_GETMNTENT || HAVE_STATFS */  
 
}

static char *
find_device(char *path)
{
#if HAVE_GETMNTENT
#if HAVE_SYS_MNTTAB_H
  struct mnttab   mnttab;
#else
  struct mntent  *mntent;
#endif
  FILE           *mntfp;
#elif HAVE_FSTAB_H
  struct fstab   *fstab;
  struct stat     stat1;
#elif HAVE_STATFS
  struct statfs   statf;
#endif
  char            tmpbuf[1024];
  static char     device[STRMAX];
#if defined(HAVE_GETMNTENT) && !defined(HAVE_SETMNTENT)
  int             i;
#endif

  device[0] = '\0';		/* null terminate the device */


  /* find the device for the path and copy the device into the
   * string declared above and at the end of the routine return it
   * to the caller 
   */
#if HAVE_FSTAB_H || HAVE_GETMNTENT || HAVE_STATFS   
#if HAVE_GETMNTENT
#if HAVE_SETMNTENT
  mntfp = setmntent(ETC_MNTTAB, "r");
  while (NULL != (mntent = getmntent(mntfp)))
    if (strcmp(path, mntent->mnt_dir) == 0) {
      copy_nword(mntent->mnt_fsname, device,
		 sizeof(device));
      DEBUGMSGTL(("ucd-snmp/disk", "Disk:  %s\n",
		  mntent->mnt_fsname));
      break;
    } else {
      DEBUGMSGTL(("ucd-snmp/disk", "  %s != %s\n",
		  path, mntent->mnt_dir));
    }
  if (mntfp)
    endmntent(mntfp);
#else                           /* getmentent but not setmntent */
  mntfp = fopen(ETC_MNTTAB, "r");
  while ((i = getmntent(mntfp, &mnttab)) == 0)
    if (strcmp(path, mnttab.mnt_mountp) == 0)
      break;
    else {
      DEBUGMSGTL(("ucd-snmp/disk", "  %s != %s\n",
		  path, mnttab.mnt_mountp));
    }
  fclose(mntfp);
  if (i == 0) {
    copy_nword(mnttab.mnt_special, device,
	       sizeof(device));
  }
#endif /* HAVE_SETMNTENT */
#elif HAVE_FSTAB_H
  stat(path, &stat1);
  setfsent();
  if ((fstab = getfsfile(path))) {
    copy_nword(fstab->fs_spec, device,
	       sizeof(device));
  }
  endfsent();
  if (device[0] != '\0') {
     /*
      * dummy clause for else below
      */
   }

#elif HAVE_STATFS
  if (statfs(path, &statf) == 0) {
    copy_nword(statf.f_mntfromname, device, sizeof(device));
    DEBUGMSGTL(("ucd-snmp/disk", "Disk:  %s\n",
		statf.f_mntfromname));
  }
#endif
  else {
    sprintf(tmpbuf, "Couldn't find device for disk %s",
	    path);
    config_pwarn(tmpbuf);
  }
#else
  config_perror("'disk' checks not supported on this architecture.");
#endif                   /* HAVE_FSTAB_H || HAVE_GETMNTENT || HAVE_STATFS */  
  return device;
}


/*
 * var_extensible_disk(...
 * Arguments:
 * vp     IN      - pointer to variable entry that points here
 * name    IN/OUT  - IN/name requested, OUT/name found
 * length  IN/OUT  - length of IN/OUT oid's 
 * exact   IN      - TRUE if an exact match was requested
 * var_len OUT     - length of variable or 0 if function returned
 * write_method
 * 
 */
u_char         *
var_extensible_disk(struct variable *vp,
                    oid * name,
                    size_t * length,
                    int exact,
                    size_t * var_len, WriteMethod ** write_method)
{

    int             percent, iserror, disknum = 0;
#if !defined(HAVE_SYS_STATVFS_H) && !defined(HAVE_STATFS)
    double          totalblks, free, used, avail, availblks;
#else
    static long     avail;
#if defined(STRUCT_STATVFS_HAS_F_FILES) || defined(STRUCT_STATFS_HAS_F_FILES)
    int             percent_inode;
#endif
#endif
    static long     long_ret;
    static char     errmsg[300];
    float           multiplier;

#if defined(HAVE_STATVFS) || defined(HAVE_STATFS)
#ifdef STAT_STATFS_FS_DATA
    struct fs_data  fsd;
    struct {
        u_int           f_blocks, f_bfree, f_bavail, f_bsize;
    } vfs;
#else
    struct statvfs  vfs;
#endif
#else
#if HAVE_FSTAB_H
    int             file;
    union {
        struct fs       iu_fs;
        char            dummy[SBSIZE];
    } sb;
#define filesys sb.iu_fs
#endif
#endif

tryAgain:
    if (header_simple_table
        (vp, name, length, exact, var_len, write_method, numdisks))
        return (NULL);
    disknum = name[*length - 1] - 1;
    switch (vp->magic) {
    case MIBINDEX:
        long_ret = disknum + 1;
        return ((u_char *) (&long_ret));
    case ERRORNAME:            /* DISKPATH */
        *var_len = strlen(disks[disknum].path);
        return ((u_char *) disks[disknum].path);
    case DISKDEVICE:
        *var_len = strlen(disks[disknum].device);
        return ((u_char *) disks[disknum].device);
    case DISKMINIMUM:
        long_ret = disks[disknum].minimumspace;
        return ((u_char *) (&long_ret));
    case DISKMINPERCENT:
        long_ret = disks[disknum].minpercent;
        return ((u_char *) (&long_ret));
    }
#if defined(HAVE_STATVFS) || defined(HAVE_STATFS)
#ifdef STAT_STATFS_FS_DATA
    if (statvfs(disks[disknum].path, &fsd) == -1)
#else
    if (statvfs(disks[disknum].path, &vfs) == -1)
#endif
    {
        snmp_log(LOG_ERR, "Couldn't open device %s\n",
                 disks[disknum].device);
        setPerrorstatus("statvfs dev/disk");
        if (!exact)
            goto tryAgain;
        return NULL;
    }
#ifdef STAT_STATFS_FS_DATA
    vfs.f_blocks = fsd.fd_btot;
    vfs.f_bfree = fsd.fd_bfree;
    vfs.f_bavail = fsd.fd_bfreen;
    vfs.f_bsize = 1024;         /*  Ultrix f_bsize is a VM parameter apparently.  */
#endif
#if defined(HAVE_ODS)
    vfs.f_blocks = vfs.f_spare[0];
    vfs.f_bfree = vfs.f_spare[1];
    vfs.f_bavail = vfs.f_spare[2];
#endif
    percent =
        vfs.f_blocks == 0 ? 0 :
        vfs.f_bavail <= 0 ? 100 :
        (int) ((double) (vfs.f_blocks - vfs.f_bfree) /
               (double) (vfs.f_blocks -
                         (vfs.f_bfree - vfs.f_bavail)) * 100.0 + 0.5);
    multiplier = (float)vfs.f_bsize / (float)1024.0;
#ifdef STRUCT_STATVFS_HAS_F_FRSIZE
    if (vfs.f_frsize > 255)
        multiplier = (float)vfs.f_frsize / (float)1024.0;
#endif
    avail = (long)(vfs.f_bavail * multiplier);
    iserror = (disks[disknum].minimumspace >= 0 ?
               avail < disks[disknum].minimumspace :
               100 - percent <= disks[disknum].minpercent) ? 1 : 0;
#if defined(STRUCT_STATVFS_HAS_F_FILES) || defined STRUCT_STATFS_HAS_F_FAVAIL
    percent_inode = vfs.f_favail <= 0 ? 100 :
        (int) ((double) (vfs.f_files - vfs.f_ffree) /
               (double) (vfs.f_files -
                         (vfs.f_ffree - vfs.f_favail)) * 100.0 + 0.5);
#else
#if defined(STRUCT_STATFS_HAS_F_FILES) && defined(STRUCT_STATFS_HAS_F_FFREE)
   percent_inode = vfs.f_files == 0 ? 100.0 :
      (int) ((double) (vfs.f_files - vfs.f_ffree) /
	          (double) (vfs.f_files) * 100.0 + 0.5);
#endif 
#endif /* defined(STRUCT_STATVFS_HAS_F_FILES) */ 
    switch (vp->magic) {
    case DISKTOTAL:
        long_ret = (long)(vfs.f_blocks * multiplier);
        return ((u_char *) (&long_ret));
    case DISKAVAIL:
        return ((u_char *) (&avail));
    case DISKUSED:
        long_ret = (long)((vfs.f_blocks - vfs.f_bfree) * multiplier);
        return ((u_char *) (&long_ret));
    case DISKPERCENT:
        long_ret = percent;
        return ((u_char *) (&long_ret));
#if defined(STRUCT_STATVFS_HAS_F_FILES) || defined (STRUCT_STATFS_HAS_F_FILES)
    case DISKPERCENTNODE:
        long_ret = percent_inode;
        return ((u_char *) (&long_ret));
#endif
    case ERRORFLAG:
        long_ret = iserror;
        return ((u_char *) (&long_ret));
    case ERRORMSG:
        if (iserror) {
            if (disks[disknum].minimumspace >= 0)
                snprintf(errmsg, sizeof(errmsg),
                        "%s: less than %d free (= %d)",
                        disks[disknum].path, disks[disknum].minimumspace,
                        (int) avail);
            else
                snprintf(errmsg, sizeof(errmsg),
                        "%s: less than %d%% free (= %d%%)",
                        disks[disknum].path, disks[disknum].minpercent,
                        percent);
            errmsg[ sizeof(errmsg)-1 ] = 0;
        } else
            errmsg[0] = 0;
        *var_len = strlen(errmsg);
        return ((u_char *) (errmsg));
    }
#else
#if HAVE_FSTAB_H
    /*
     * read the disk information 
     */
    if ((file = open(disks[disknum].device, 0)) < 0) {
        snmp_log(LOG_ERR, "Couldn't open device %s\n",
                 disks[disknum].device);
        setPerrorstatus("open dev/disk");
        if (!exact)
            goto tryAgain;
        return (NULL);
    }
    lseek(file, (long) (SBLOCK * DEV_BSIZE), 0);
    if (read(file, (char *) &filesys, SBSIZE) != SBSIZE) {
        setPerrorstatus("open dev/disk");
        snmp_log(LOG_ERR, "Error reading device %s\n",
                 disks[disknum].device);
        close(file);
        if (!exact)
            goto tryAgain;
        return (NULL);
    }
    close(file);
    totalblks = filesys.fs_dsize;
    free = filesys.fs_cstotal.cs_nbfree * filesys.fs_frag +
        filesys.fs_cstotal.cs_nffree;
    used = totalblks - free;
    availblks = totalblks * (100 - filesys.fs_minfree) / 100;
    avail = availblks > used ? availblks - used : 0;
    percent =
        totalblks == 0 ? 0 :
        availblks == 0 ? 100 :
        (int) ((double) used / (double) totalblks * 100.0 + 0.5);
    multiplier = (float)filesys.fs_fsize / (float)1024.0;
    iserror =
        (disks[disknum].minimumspace >= 0
            ? avail * multiplier < disks[disknum].minimumspace
            : 100 - percent <= disks[disknum].minpercent) ? 1 : 0;
    switch (vp->magic) {
    case DISKTOTAL:
        long_ret = (long)(totalblks * multiplier);
        return ((u_char *) (&long_ret));
    case DISKAVAIL:
        long_ret = (long)(avail * multiplier);
        return ((u_char *) (&long_ret));
    case DISKUSED:
        long_ret = (long)(used * multiplier);
        return ((u_char *) (&long_ret));
    case DISKPERCENT:
        long_ret = percent;
        return ((u_char *) (&long_ret));
    case ERRORFLAG:
        long_ret = iserror;
        return ((u_char *) (&long_ret));
    case ERRORMSG:
        if (iserror) {
            if (disks[disknum].minimumspace >= 0)
                snprintf(errmsg, sizeof(errmsg),
                        "%s: less than %d free (= %d)",
                        disks[disknum].path, disks[disknum].minimumspace,
                        avail * filesys.fs_fsize / 1024);
            else
                snprintf(errmsg, sizeof(errmsg),
                        "%s: less than %d%% free (= %d%%)",
                        disks[disknum].path, disks[disknum].minpercent,
                        percent);
            errmsg[ sizeof(errmsg)-1 ] = 0;
        } else
            errmsg[0] = 0;
        *var_len = strlen(errmsg);
        return ((u_char *) (errmsg));
    }
#endif
#endif
    return NULL;
}
