Re: [gentoo-user] To mount or not to Mount proc, that is the question

["Canek Peláez Valdés" <caneko@gmail.com>]

On Fri, Mar 16, 2012 at 3:18 PM, Mark Knecht <markknecht@gmail.com> wrote:
> On Fri, Mar 16, 2012 at 12:47 PM, Canek Peláez Valdés <caneko@gmail.com> wrote:
>> On Fri, Mar 16, 2012 at 1:40 PM, Mark Knecht <markknecht@gmail.com> wrote:
> <SNIP>
>>> Looking at the Gentoo amd64 install guide here:
>>>
>>> http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?part=1&chap=8
>>>
>>> it appears that the recommendation is to mount proc.
>>>
>>> [QUOTE]
>>>
>>> /dev/sda1   /boot        ext2    defaults,noatime     1 2
>>> /dev/sda2   none         swap    sw                   0 0
>>> /dev/sda3   /            ext3    noatime              0 1
>>>
>>> /dev/cdrom  /mnt/cdrom   auto    noauto,user          0 0
>>>
>>> proc        /proc        proc    defaults             0 0
>>> shm         /dev/shm     tmpfs   nodev,nosuid,noexec  0 0
>>>
>>> [QUOTE]
> <SNIP>
>>
>> I haven't put /proc explicitly on my /etc/fstab since a long time ago,
>> and everything seems to be working. However, I use systemd, which
>> always mounts /proc with the default options, and only uses the entry
>> in /etc/fstab (if present) to override the default options. In other
>> words, systemd always mounts /proc, no matter if it's listed in
>> /etc/fstab or not.
>>
>> I don't know what OpenRC does, but it would not surprise me that it's
>> something similar.
>>
>> Regards.
>> --
>> Canek Peláez Valdés
>> Posgrado en Ciencia e Ingeniería de la Computación
>> Universidad Nacional Autónoma de México
>>
>
> Thanks Canek. I appreciate your response.
>
> It seems when rereading the link above the authors do put the work
> 'example' in italics, implying that possibly I should know what I'm
> doing and not depend on the text on that page. I'm fine with the not
> depending part. I'm not so sure about the 'know what I'm doing' part.
> ;-)
>
> I'm going to take a wild guess that it's somehow mounted in an init
> script these days but I have no reason to know that's actually how it
> gets done. I did read the kernel docs and it doesn't seem to be done
> automatically by the kernel AFAICT.

No, it's the init system; look at /lib/rc/sh/init.sh:66:

# By default VServer already has /proc mounted, but OpenVZ does not!
# However, some of our users have an old proc image in /proc
# NFC how they managed that, but the end result means we have to test if
# /proc actually works or not. We do this by comparing two reads of
# /proc/self/environ for which we have set the variable VAR to two
# different values. If the comparison comes back equal, we know that
# /proc is not working.
mountproc=true
f=/proc/self/environ
if [ -e $f ]; then
        if [ "$(VAR=a cat $f)" = "$(VAR=b cat $f)" ]; then
                eerror "You have cruft in /proc that should be deleted"
        else
                einfo "/proc is already mounted, skipping"
                mountproc=false
        fi
fi
unset f

if $mountproc; then
        procfs="proc"
        [ "$RC_UNAME" = "GNU/kFreeBSD" ] && proc="linprocfs"
        ebegin "Mounting /proc"
        if ! fstabinfo --mount /proc; then
                mount -n -t "$procfs" -o noexec,nosuid,nodev proc /proc
        fi
        eend $?
fi

Mistery solved :D

Regards.
-- 
Canek Peláez Valdés
Posgrado en Ciencia e Ingeniería de la Computación
Universidad Nacional Autónoma de México