svn commit: r313450 - in stable/11: lib/libc/gen lib/libc/sys sys/compat/freebsd32 sys/kern sys/sys

[Slawa Olhovchenkov]

On Tue, Mar 21, 2017 at 08:05:31PM -0700, John Baldwin wrote:

> On Wednesday, March 15, 2017 05:30:53 PM Slawa Olhovchenkov wrote:
> > On Wed, Feb 08, 2017 at 06:32:35PM +0000, John Baldwin wrote:
> > 
> > > Author: jhb
> > > Date: Wed Feb  8 18:32:35 2017
> > > New Revision: 313450
> > > URL: https://svnweb.freebsd.org/changeset/base/313450
> > > 
> > > Log:
> > >   MFC 310638:
> > >   Rename the 'flags' argument to getfsstat() to 'mode' and validate it.
> > >   
> > >   This argument is not a bitmask of flags, but only accepts a single value.
> > >   Fail with EINVAL if an invalid value is passed to 'flag'.  Rename the
> > >   'flags' argument to getmntinfo(3) to 'mode' as well to match.
> > >   
> > >   This is a followup to r308088.
> > 
> > >  kern_getfsstat(struct thread *td, struct statfs **buf, size_t bufsize,
> > > -    size_t *countp, enum uio_seg bufseg, int flags)
> > > +    size_t *countp, enum uio_seg bufseg, int mode)
> > >  {
> > >  	struct mount *mp, *nmp;
> > >  	struct statfs *sfsp, *sp, *sptmp, *tofree;
> > >  	size_t count, maxcount;
> > >  	int error;
> > >  
> > > +	switch (mode) {
> > > +	case MNT_WAIT:
> > > +	case MNT_NOWAIT:
> > > +		break;
> > > +	default:
> > > +		return (EINVAL);
> > > +	}
> > >  restart:
> > 
> > This is break net-snmp UCD-SNMP-MIB::dskTable oid:
> > 
> >  82434 snmpd    CALL  getfsstat(0,0,<invalid=0>)
> >  82434 snmpd    RET   getfsstat -1 errno 22 Invalid argument
> >  82434 snmpd    CALL  getfsstat(0,0xfffffffffffffe28,MNT_NOWAIT)
> >  82434 snmpd    RET   getfsstat -1 errno 22 Invalid argument
> >  82434 snmpd    CALL  write(0x9,0x800f162ea,0x1)
> 
> This doesn't seem to match the code in the port:
> 
> void
> Init_HR_FileSys(void)
> {
> #if HAVE_GETFSSTAT
> #if defined(HAVE_STATVFS) && defined(__NetBSD__)
>     fscount = getvfsstat(NULL, 0, ST_NOWAIT);
> #else
>     fscount = getfsstat(NULL, 0, MNT_NOWAIT);
> #endif
>     if (fsstats)
>         free((char *) fsstats);
>     fsstats = NULL;
>     fsstats = malloc(fscount * sizeof(*fsstats));
> #if defined(HAVE_STATVFS) && defined(__NetBSD__)
>     getvfsstat(fsstats, fscount * sizeof(*fsstats), ST_NOWAIT);
> #else
>     getfsstat(fsstats, fscount * sizeof(*fsstats), MNT_NOWAIT);
> #endif
>     HRFS_index = 0;
> 
> (Here it always calls with MNT_NOWAIT)  This is for net-snmp 5.7.3,
> but it seems like that code hasn't changed in quite a while.

I see, strange. I am also use net-snmp 5.7.3 (net-snmp-5.7.3_12).

# dtrace -n 'syscall:freebsd:getfsstat:entry { printf("%s %p %d %d\n", execname, args[0], args[1], args[2]); stack(); ustack();}'
dtrace: description 'syscall:freebsd:getfsstat:entry ' matched 1 probe
CPU     ID                    FUNCTION:NAME
 22  43059                  getfsstat:entry snmpd 0 0 0

              kernel`amd64_syscall+0x36b
              kernel`0xffffffff8071c84b

              libc.so.7`getfsstat+0xa
              libnetsnmpmibs.so.30.0.3`netsnmp_fsys_load+0x9
              libnetsnmpagent.so.30.0.3`0x80083dfbf
              libnetsnmpmibs.so.30.0.3`var_extensible_disk+0x38
              libnetsnmpagent.so.30.0.3`netsnmp_old_api_helper+0x18f
              libnetsnmpagent.so.30.0.3`netsnmp_call_handler+0x134
              libnetsnmpagent.so.30.0.3`netsnmp_bulk_to_next_helper+0x1a1
              libnetsnmpagent.so.30.0.3`netsnmp_call_handler+0x134
              libnetsnmpagent.so.30.0.3`handle_var_requests+0x67
              libnetsnmpagent.so.30.0.3`handle_getnext_loop+0x244
              libnetsnmpagent.so.30.0.3`netsnmp_handle_request+0x186
              libnetsnmpagent.so.30.0.3`handle_snmp_packet+0x140
              libnetsnmp.so.30.0.3`0x800ece6c6
              libnetsnmp.so.30.0.3`_sess_read+0x5b9
              libnetsnmp.so.30.0.3`snmp_read2+0x3b
              snmpd`0x404cab
              snmpd`0x40317f
              ld-elf.so.1`0x800629000

Ok, what is it:

/*
 * Wrapper routine for re-loading filesystem statistics on demand
 */
int
netsnmp_fsys_load( netsnmp_cache *cache, void *data )
{
    /* XXX - check cache timeliness */
    return _fsys_load();
}

/*
 * Architecture-independent processing of loading filesystem
 statistics
 */
static int
_fsys_load( void )
{
    netsnmp_fsys_arch_load();
    /* XXX - update cache timestamp */
    return 0;
}

agent/mibgroup/hardware/fsys/fsys_getfsstats.c:

void
netsnmp_fsys_arch_load( void )
{   
    int n, i;
    struct NSFS_STATFS *stats;
    netsnmp_fsys_info *entry;

    /*
     * Retrieve information about the currently mounted filesystems...
     */
    n = NSFS_GETFSSTAT( NULL, 0, 0 );
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^