hello,
On 2017-11-27 10:31, Gerhard Roth wrote:
> On Sat, 25 Nov 2017 11:42:07 -0700 Joel Knight <[email protected]> wrote:
> > On Thu, Mar 9, 2017 at 10:02 PM, Joel Knight <[email protected]> wrote:
> > > Hi.
> > >
> > > snmpd(8) uses unsigned ints internally to represent the size and used
> > > space of a file system. The HOST-RESOURCES-MIB defines the valid
> > > values for those OIDs as 0..2147483647. With sufficiently large file
> > > systems, this can cause negative numbers to be returned for the size
> > > and used space OIDs.
> > >
> > > .1.3.6.1.2.1.25.2.3.1.5.36=-1573167768
> >
> > Hi. Just wanted to bump this again and see if anyone that cares about
> > snmp could take a look? Looking for oks and someone who wouldn't mind
> > committing it.
> >
> >
> > > At sthen's suggestion, do what net-snmp does and fiddle with the
> > > values to prevent wrapping. Yes this mucks with the actual values of
> > > size, used space, and block size, but it allows snmpd to convey the
> > > proper size and used space of the file system which is what most
> > > everybody is really interested in.
> > >
> > > In case gmail hoses this diff, it's also here:
> > > https://www.packetmischief.ca/files/patches/snmpd.hrstorage2.diff
>
>
> Hi Joel,
>
> I think this won't work unless you also change the type of 'size' and
> 'used' to u_int64_t.
I ran into an issue where my snmpd underreported my filesystem size.
$ df -h /ftp
Filesystem Size Used Avail Capacity Mounted on
/dev/sd0a 50.5T 13.7T 34.3T 29% /ftp
However snmp reports something different.
$ snmp walk -v 2c -c public localhost hrStorage
hrStorageDescr.40 = STRING: /ftp
hrStorageAllocationUnits.40 = INTEGER: 8192 Bytes
hrStorageSize.40 = INTEGER: 2487209520
sthen@ pointed me to this thread but suggested 'int_t' as opposed to
'u_int_64_t', making that change and applying it fixes the issue for
me.
hrStorageDescr.40 = STRING: /ftp
hrStorageAllocationUnits.40 = INTEGER: 32768
hrStorageUsed.40 = INTEGER: 459624840
Updated patch attached.
thanks,
.jh
Index: usr.sbin/snmpd/mib.c
===================================================================
RCS file: /cvs/src/usr.sbin/snmpd/mib.c,v
retrieving revision 1.99
diff -u -p -u -p -r1.99 mib.c
--- usr.sbin/snmpd/mib.c 15 May 2020 00:56:03 -0000 1.99
+++ usr.sbin/snmpd/mib.c 1 Jul 2020 14:22:59 -0000
@@ -563,7 +563,7 @@ mib_hrstorage(struct oid *oid, struct be
u_int32_t idx;
struct statfs *mntbuf, *mnt;
int mntsize, maxsize;
- u_int32_t units, size, used, fail = 0;
+ size_t units, size, used, fail = 0;
const char *descr = NULL;
int mib[] = { CTL_HW, 0 };
u_int64_t physmem, realmem;
@@ -643,6 +643,14 @@ mib_hrstorage(struct oid *oid, struct be
units = mnt->f_bsize;
size = mnt->f_blocks;
used = mnt->f_blocks - mnt->f_bfree;
+
+ /* for large filesystems, do not overflow hrStorageSize */
+ while (size > INT32_MAX) {
+ size = size >> 1;
+ units = units << 1;
+ used = used >> 1;
+ }
+
sop = &so[3];
break;
}
