Re: [gentoo-user] [SOLVED] gcc-6.4.0-r1::gentoo failed (compile phase)

On 03/28/2018 12:08 PM, thelma@×××××××××××.com wrote:
> On 03/28/2018 10:40 AM, Peter Humphrey wrote:
>> On Wednesday, 28 March 2018 16:14:49 BST thelma@×××××××××××.com wrote:
>>> On 03/28/2018 01:32 AM, Peter Humphrey wrote:
>> [...]
>>>> I have a similar system, but Atom N270. I wouldn't want to compile much on
>>>> it, and certainly not GCC. I NFS-export its $PORTDIR to this much more
>>>> powerful box, do the emerging here and then just install packages on the
>>>> Atom. Still not exactly fast, but incomparably better.
>>>
>>> I should have done it as well, it is a bit too late I have only
>>> 45-packages left to compile out of 710.
>>> Is it better use NFS or distcc?
>>> Do you have a good link how to do it with: "NFS-export  $PORTDIR"
>>
>> I think NFS may be simpler to operate, but that may be because I'm more
>> familiar with it. You just need something like this in the Atom's /etc/
>> exports: /usr/portage 192.168.1.5(rw,no_subtree_check,anonuid=250,anongid=250,no_wdelay)
>>
>> That IP address is the big beast host, and of course 250 is the portage user.
>>
>> I don't know of a guide on the web, but basically, the method is to construct
>> a 32-bit chroot on your host system and install a mirror of your Atom system
>> in it. Copy your Atom's /etc/portage directory into the chroot and adjust
>> things like --jobs to suit the chroot host, but make sure all the USE flags
>> are the same as on the Atom. It'll take an hour or two to build the system,
>> but you only have to do it once, and of course it'll be done at the speed of
>> your host machine. You don't need to keep running etc-update or equivalent;
>> just build the binaries.
>>
>> My chroot is /mnt/atom and this script starts it ready to chroot into:
>>
>> $ cat /etc/init.d/atom
>> #!/sbin/openrc-run
>>
>> depend() {
>>    need localmount
>>    need bootmisc
>> }
>>
>> start() {
>>     ebegin "Mounting 32-bit chroot dirs under /mnt/atom"
>>     mount -t proc /proc /mnt/atom/proc
>>     mount --rbind /dev /mnt/atom/dev
>>     mount --rbind /sys /mnt/atom/sys
>>     mount -t tmpfs tmpfs -o noatime,nosuid,nodev,noexec,mode=1777 /mnt/atom/tmp
>>     mount -t tmpfs tmpfs -o noatime,uid=portage,gid=portage,mode=0775 /mnt/atom/var/tmp/portage
>>     mount -t nfs -o vers=3 192.168.1.2:/usr/portage /mnt/atom/usr/portage
>>     rm -f /mnt/atom/etc/mtab
>>     cp /etc/mtab.atom /mnt/atom/etc/mtab
>>     eend $? "Error mounting 32-bit chroot directories"
>> }
>>
>> stop() {
>>     ebegin "Unmounting 32-bit /mnt/atom chroot dirs"
>>     rm /mnt/atom/etc/mtab
>>     ln -s /proc/self/mounts /mnt/atom/etc/mtab
>>     umount -R /mnt/atom
>>     mount /mnt/atom
>> }
>>
>> You may prefer not to bother with tmpfs, but I have 32GB RAM on my host, so
>> it's efficient here. That IP address is the Atom machine.
>>
>> No doubt someone more skilled than me at bash scripting could improve on my
>> script; suggestions welcome.
>>
>> After updating the chroot you can emerge -k or -K on your Atom machine, after
>> syncing which will now be the most time-consuming part of the operation.
>>
>> Let me know if anything isn't clear.
>>
>> Thanks to Neil Bothwick, who showed me how to do this several years ago.
>
> I will try do it but I'm trying to decipher the code your wrote :-)
> My atom-330 is 64-bit.
> I think your approach was discussed in this forum topic:
> https://forums.gentoo.org/viewtopic-p-6817608.html#6817608
>
> -------copy------------
> #!/bin/sh
>
> HOST=${0##*/}
> HOST=${HOST#*-}
>
> mkdir -p --mode=0755 /mnt/${HOST}
>
> mount -t nfs -o rw,intr,noatime,actimeo=60,vers=4,fsc ${HOST}:/ /mnt/${HOST}
> mount --bind /dev /mnt/${HOST}/dev
> mount --bind /dev/shm /mnt/${HOST}/dev/shm
> mount --bind /proc /mnt/${HOST}/proc
> mount --bind /sys /mnt/${HOST}/sys
> mount --bind /usr/portage /mnt/${HOST}/usr/portage
> mount --bind /usr/local/portage /mnt/${HOST}/usr/local/portage
> mount --bind /var/tmp/portage /mnt/${HOST}/var/tmp/portage
>
> env -i - HOME="/root" TERM="$TERM" chroot /mnt/${HOST} /bin/bash -l
>
> umount /mnt/${HOST}/dev/shm
> umount /mnt/${HOST}/dev
> umount /mnt/${HOST}/proc
> umount /mnt/${HOST}/sys
> umount /mnt/${HOST}/usr/portage
> umount /mnt/${HOST}/usr/local/portage
> umount /mnt/${HOST}/var/tmp/portage
> umount /mnt/${HOST}
> ------end copy--------------

Can anybody explain what these two line do in the above script?
HOST=${0##*/}
HOST=${HOST#*-}

--
Thelma